key: cord-0035965-w647vw8o
authors: Gross, David R.
title: Other Transgenic Animal Models Used in Cardiovascular Studies
date: 2009-04-18
journal: Animal Models in Cardiovascular Research
DOI: 10.1007/978-0-387-95962-7_14
sha: bc691c27f2d51a710231042be76b27ac0a7b847a
doc_id: 35965
cord_uid: w647vw8o

Previous chapters have described a large number of transgenic animal models used to study specific cardiovascular syndromes. This chapter will fill in some gaps. Many of these transgenic animals were developed to study normal and/or abnormal physiological responses in other organ systems, or to study basic biochemical and molecular reactions or pathways. These models were then discovered to also have effects on the cardiovascular system, some of them unanticipated. A word of caution, particularly when highly inbred mouse strains are used to develop transgenic models - not all strains of a particular species are created equal. When cardiovascular parameters of age- and sex-matched A/J and C57BL/6J inbred mice were compared the C57BL/6J mice demonstrated eccentric physiologic ventricular hypertrophy, increased ventricular function, lower heart rates, and increased exercise endurance.(1)

lacZ gene was used in two transgenic models (cGATA6/lacZ and cardiac conduction system/lacZ) and two targeted gene knock-in models (minK/lacZ and Hop/lacZ) in an attempt to mark portions of the proximal and distal atrioventricular conduction system (AVCS) in mice. Beta-gal expression was consistently observed in the proximal and distal AVCS but it was also observed in the working myocardium outside the AVCS. The reporter system was not expressed in the SA node, and thus it limits the technique. 6

Studies using estrogen deletion, 7 phytoestrogen feeding, 8 genetic models, and estrogen receptor antagonists and agonists have demonstrated that both estrogen receptor subtypes ( a and b ) protect against various forms of cardiovascular disease including ischemia-reperfusion injury, hypertension, ventricular hypertrophy, and chronic heart failure. 9 When low-density lipoprotein LDL −/− female mice were treated with estrogen (E2) there was a delay in atherosclerotic plaque formation. This delay was associated with an increase in DNA strand breaks in the arterial wall. When the same mouse model was fed a high-cholesterol diet and ovarioectomized there was an increase in atherogenesis. 10 Aromatase knockout mice, both males and females, suffer from a variety of abnormalities including loss of fertility and libido, bone loss, cardiovascular and cerebrovascular problems, and development of metabolic syndrome. 11 Treating arteries from male estrogen receptor-a knockout (ERKO) mice with specific aromatase short-interfering RNA for 72 h knocked down the aromatase mRNA and protein associated with elimination of epoxyeicosatrienoic acid (EET) mediation of flowinduced dilation. This indicates that flow-induced dilation in male ERKO mice arteries is maintained by an EDHF/EET-mediated mechanism compensating for reduced NO because of reduced estrogen aromatized from testosterone. 12 We were able to demonstrate the important role of estrogen receptor-a in cardiac ischemia-reperfusion injury. 13 Nuclear ER-a −/− (ERKO) mice were used to show that ER-a target genes involved in energy substrate oxidation, ATP synthesis, and phosphate transfer are downregulated at baseline and following pressure overload.

The results indicate that ER-a is required for the adaptive bioenergetic response to pressure overload heart failure. 14 During acute lipopolysaccharide (LPS)-induced inflammatory responses ER-a mediates NO synthesis and the vascular responses to NO involving soluble guanylate cyclase. 15 ER-b −/− (BERKO) mice were used to show that ER-b -mediated mechanisms protect against left ventricular hypertrophy. 16 E2 (estrogen) mitigates Angio-II signaling that produces hypertrophy and fibrosis in female BERKO mice. 17 BERKO mice are protected against high-fat diet-induced insulin resistance and glucose intolerance. The protection involves augmented PPAR-g signaling in adipose tissue and overexpression of nuclear coactivators such as SRC1 and TIF2. 18 ER-b also plays a role in the cardioprotective effects of estrogen following global, warm ischemia-reperfusion injury. 19 Myocardial infarction-induced heart failure in female BERKO mice resulted in increased mortality, increased levels of clinical and biochemical markers of heart failure, and impaired expression of Ca 2+ -handling proteins. 20 Estrogenic effects on Ca 2+ currents in isolated ventricular cardiomyocytes from WT, ERKO, and BERKO mice show that the inhibition of Ca 2+ currents and decreased contractility are not dependent upon ER-a or b . 21 ERKO and BERKO mice were used to reveal that ER-a -and ER-b -dependent pathways regulate distinct, and mostly nonoverlapping, sets of genes that function as an estrogen-regulatory transcriptional network in the vasculature. 22 ER-b seems to modify adrenergic control of small artery tone in males but not in females. This is demonstrated by a gender-specific (male) enhanced response to phenylephrine 23 and reduced endothelium-derived hyperpolarizing factor (EDHF)-mediated relaxation via gap junction communication. 24 NO appears to contribute to the vasodilation response to E2 in femoral arteries from BERKO but not WT mice. 25 ERs play a sex-specific role in small mesenteric arterial estrogen-mediated flow responses and distensibility. Deletion of ER-b affects arterial structure only in male BERKO. 26 In vascular smooth muscle cells (VSMC) human-inducible nitric oxide synthase (iNOS) transcription is positively regulated by ER-b and negatively regulated by ER-a . 27 Knocking out the gene encoding the catabolic enzyme CYP7B1 decreased estrogen-dependent expression of NOS and repressed carotid artery reendothelialization following endothelial injury. 28 Female follitropin-receptor knockout (FORKO) mice have an impaired natriuretic peptide system. This could contribute to the susceptibility to develop age-related hypertension in female FORKO mice. This model shows a relationship between estrogen, adipose tissue, and ANP, and it is used as a model for menopause. 29 Aged FORKO mice developed higher levels of Angio-II-induced hypertension, ventricular hypertrophy, and myocardial fibrosis than age-matched WT controls. The Angio-IIinduced ventricular hypertrophy and myocardial fibrosis are associated with downregulation of the endogenous antioxidant thioredoxin (Trx) and upregulation of apoptosis-signal-regulated kinase-1 (ASK-1)/caspase signaling in the FORKO mice. 30 

Transgenic mice overexpressing cardiac-specific Lats2, a serine/threonine kinase, have significantly reduced left and right ventricular mass whereas transgenic mice overexpressing dominant-negative Lats2 demonstrate biventricular hypertrophy. 31 G-protein-coupled receptor (GPCR) kinase 2 (GRK-2) is also a serine/threonine kinase. It phosphorylates and desensitizes agonist-bound GPCRs. GRK-2 levels in VSMC are increased in animal models of hypertension. In GRK-2 knockout mice b -adrenergic receptor-mediated dilation was increased while a -adrenergic-mediated vasoconstriction was also increased. 32 Confocal studies of cardiac tissue from transgenic mice overexpressing GRK-2 show a clear increase in relative fluorescence intensity of GRK-2 in the arrhythmia-prone subepicardial border zone following coronary artery ligation. 33 Myocardial thrombin signaling, as assessed by p42/p44 mitogen-activated protein kinase activation, was significantly attenuated in transgenic mice with cardiac specific overexpression of GRK-3. 34 Transgenic mice overexpressing cardiac-specific dominant-negative glycogen synthase kinase-b (GSK-3-b DN) were produced. Persistent inhibition of GSK-3-b induced compensatory hypertrophy, inhibited apoptosis and fibrosis, and increased cardiac contractility. The antiapoptosis effects of GSK-3-b inhibition are mediated by myeloid cell leukemia-1. 35 When GSK-3-b was used to create a double-transgenic mouse by breeding with a mouse model of hypertrophic cardiomyopathy (HCM) the male animals had reduced contractility, reduced sarcoplasmic (endo) reticulum Ca 2+ -ATPase expression, elevated ANF expression, and premature death. Female HCM/GSK-3-b doubletransgenic mice demonstrated cardiac histology, function, and survival the same as their female HCM littermates. 36 Hypertension was induced using uninephrectomy and DOCA-salt in Axl (a receptor tyrosine kinase) knockout (Axl −/− ) mice. The results indicate a likely mechanism for Axl-dependent effects on hypertension. 37 Studies conducted in serum-and glucocorticoid-inducible kinase-1 knockout mice (SGK-1 −/− ) indicate that this kinase may play a decisive role in fetal programming of hypertension induced by prenatal protein restriction. 38 Reactive oxygen species (ROS) generated during ischemic preconditioning could be responsible for altering mitochondrial metabolism by oxidizing key mitochondrial enzymes in the hearts of protein kinase C-delta knockout (PKC-delta −/− ) mice. Metabolic adaptation to preconditioning is also impaired in this animal model. 39 In transgenic mice that overexpress specific cardiomyocyte Ca 2+ /calmodulindependent myosin light chain kinase-increased regulatory light chain phosphorylation was not responsible for cardiac hypertrophy. It apparently inhibits hypertrophy by contributing to enhanced contractility and myocardial efficiency. 40 The hearts of transgenic mice overexpressing the regulatory g -subunit of AMPactivated protein kinase (PPKAG2) resist low-flow ischemic injury better than controls. This resistance was associated with increased consumption of glycogen but this was unrelated to AMP-activated protein kinase activation. 41 The intimal thicknessrelated receptor (ITR) is expressed in rabbit aortic smooth muscle cells following injury. The sequence contains a motif common to the Rhodopsin-like GPCR superfamily. ITR seems to be a novel receptor that could play a role in vascular remodeling. 42 Cardiac-specific transgenic mice with increased or decreased phosphoinositide 3-kinase (PI3K) activity were crossed with a transgenic mouse model of dilated cardiomyopathy (DCM). Exercise training and increased PI3K activity prolonged survival in the DCM model by 15-20%. Reduced PI3K activity shortened survival by about 50%. 43

Transgenic mice deficient in gp91phox, an NADPH oxidase subunit protein, designated gp91 −/− mice were used to define mechanisms involved in DOCA-salt-induced hypertension. The findings indicated that vascular superoxide ion overproduction via gp91phox-containing NADPH oxidase is involved in the development of hypertension in this model. 44 Using mice lacking the p47phox subunit of the NADPH oxidase (p47phox −/− ) Salguero et al. 45 show that in WT mice 2K1C hypertension was associated with a fourfold increase in endothelial progenitor cells (EPCs). In p47phox −/− mice there was a significantly less increase in arterial pressures and no change in EPCs.

Coronary ligation was performed in gp91phox −/− and WT mice. Mortality was significantly higher in the gp91phox −/− mice but the progression of left ventricular remodeling was not affected by phenotype. Systemic oxidative stress was not reduced in gp91phox −/− mice since there was a significant increase in lipid peroxides probably mediated by the observed increase of the NADPH subunit nox-1 in gp91phox −/− mice. 46 Heme oxygenase is a cytoprotective enzyme that degrades heme to generate carbon monoxide, bilirubin, and iron. Two rodent models, Gunn rats (hyperbilirubinemic) and heme oxygenase-1 knock out (HO-1 −/− ) mice, were used to evaluate DOCA-salt hypertension. Uninephrectomized WT rats treated with DOCA-salt had significantly increased arterial pressures but the response was attenuated in Gunn rats. The response in the Gunn rats was not due to a greater induction of HO-1 in the vasculature or due to an increase in renal Na + excretion. Using HO-1 −/− mice Wiesel et al. 47 reported that chronic deficiency of HO-1 does not alter basal blood pressure, but when the HO-1 −/− mice were exposed to 1K1C there was more severe renovascular hypertension and cardiac hypertrophy, an increase in ischemic damage, and higher mortality rates. DOCA-salt induced HO-1 protein in HO-1 +/+ mice but there was no increase in arterial pressures. The same DOCA-salt regimen in HO-1 −/− mice produced significant increases in arterial pressures. 48

Adenosine receptors belong to a large family of GPCRs containing four receptor subtypes. In keeping with the physiological model of yin and yang (accelerator and brake), receptor subtypes designated A1R and A3R mediate inhibition of adenylyl cyclase and subtypes A2aR and A2bR mediate stimulation of adenylyl cyclase. All of the identified receptor subtypes have now been used to create knockout mouse models and some have been used in overexpression models. Various activities related to normal cardiovascular function and to CNS regulation of CV function have been identified using these transgenic models. Some responses are reduced and others enhanced depending upon the specific receptor that has been deleted or overexpressed. 49 Some examples are as follows: in the mouse heart, A1R inhibits b -adrenergic-induced myocardial contractility whereas A2aR opposes the action of A1R and enhances myocardial contractility. During low-flow myocardial ischemia A2aR supports myocardial contractility. 50 Mice with deletion of adenylyl cyclase type V (AC-V −/− ) demonstrate enhanced basal left ventricular function than WT controls, but there is a reduced response to b -adrenergic stimulation. 51 In the subcommissural bed nucleus of the stria terminalis norepinephrine (NE)induced decreases in synaptic transmission are markedly reduced in a 2-adrenergic receptor knockout ( a 2-AR −/− ) mice. 52 a 2-ARs directly regulate the release of NE, but not dopamine, at the terminal level in the nucleus accumbens in mice. a 2-AR −/− mice have been used to show that these receptors regulate dopamine indirectly via their effects on dopamine neurons in the ventral tegmental area. The mechanism(s) for this indirect regulation were yet to be described in 2004. 53 In WT mice rilmenidine, moxonidine, and clonidine all produce dose-dependent decreases in blood pressure and heart rate. In D79N a 2-AR −/− mice there were no responses to these agents indicating that a 2-ARs are responsible for the cardiovascular effects of these drugs. 54 a 2c-AR overexpression increased the development of behavioral despair and associated cardiovascular responses associated with increased corticosterone levels following stress. a -2c −/− mice demonstrated attenuated corticosterone levels and cardiovascular responses when exposed to equal levels of stress. 55 The effects of alterations in the level of myocardial b -adrenergic receptor kinase ( b -ARK-1) were studied in b -ARK-1 +/− (heterozygous) mice and a mouse model heterozygous for b -ARK-1 and transgenic for cardiac-specific overexpression of b -ARK-1 COOH-terminal inhibitor peptide ( b -ARK-1 +/− / b -ARK-1ct). These studies suggest that the level of b -ARK-1 activity can modulate contractile function. Even partial inhibition of b -ARK-1 activity enhances b -adrenergic receptor signaling and results in improved catecholamine responsiveness. 56 Dopamine (D2)-receptor knockout (D2R −/− ) mice were used to demonstrate that pituitary vascular endothelial growth factor (VEGF) expression is under dopaminergic control and may be critical for pituitary angiogenesis via paracrine actions in female D2R −/− mice. 57 "Beta-less" mice are triple adrenoreceptor knockouts ( b -1/ b -2/ b -3 AR −/− ). In these animals the lipolytic response to NE and b -AR agonists is blunted, but a residual low-affinity lipolytic effect is observed in the presence of catecholamines and b -3-AR agonists but not b -1-or b -2-AR agonists. The residual lipolytic effect is attributed to an unknown GPCR with low affinity for catecholamines. 58

In eNOS −/− mice, chronically treated with l -NAME, blood pressure decreased while eNOS +/− and eNOS +/+ mice both developed hypertension. 59 eNOS −/− mice also develop fasting hyperinsulinemia, hyperlipidemia, and decreased insulin-stimulated glucose uptake. 60 Pulmonary endothelial cells were isolated from eNOS −/− mice and grown without E2. In control WT cells E2 significantly increased telomerase activity but in the eNOS −/− cells exogenous eNOS or an NO donor were needed to normalize the level of telomerase activity. 61 Billon et al. 62 used eNOS −/− mice to document that the presence, but not the enzymatic activity, of eNOS is necessary for estrogen signaling in the endothelium.

Transgenic mice that overexpress eNOS were used to discover that ventilatorinduced lung injury could be reduced significantly by excess eNOS. The mechanism for this protection seems to be inhibition of the production of inflammatory chemokines and cytokines associated with neutrophilic infiltration. 63 eNOS overexpression is also able to prevent the development of 2K1C renovascular hypertension in mice. 64 At the University of Missouri-Columbia transgenic pigs carrying an endogenous eNOS gene driven by a Tie-2 promoter and tagged with a V5 His tag have been developed. 65

Obesity and obesity-linked insulin resistance are significant causes of the metabolic syndrome characterized by adipocyte hypertrophy. Adipose tissue is an important regulator of energy homeostasis. It functions as an endocrine organ secreting adipokines including adiponectin (APN). Studies using adiponectin transgenic (overexpression) and knockout mice demonstrate that adiponectin is an insulinsensitizing adipokine and that obesity can result in insulin resistance and diabetes. At least two different adiponectin receptors have been cloned (AdipoR1 and ApipoR2) comprising a novel cell-surface receptor family acting as receptors for globular and full-length adiponectin. These receptors mediate increased activity of AMP-activated protein kinase, and PPAR-a , as well as glucose uptake and fattyacid oxidation by adiponectin. 66 , 67 Intraglomerular macrophage infiltration and mRNA levels of VCAM-1, MCP-1, TNF-a , TGF-b , collagen type I/III, and NADPH oxidase are all increased in adiponectin knockout (APN −/− ) mice than in WT, when subjected to subtotal nephrectomy and the resulting hypertension. Changes in the APN −/− mice resulted in glomerular and tubulointerstitial injury from increased inflammation and oxidative stress. 68 Studies conducted on transgenic mice overexpressing native full-length APN, targeted to white adipose tissue, revealed that adipose mass and adipocyte size were reduced while caloric intake was maintained constant. APN −/− mice also show decreases in preadipocyte factor-1 mRNA and increased CCAAT/enhancer binding protein-a in white adipose tissue. 69 Shinmura et al. 70 compared adiponectin antisense transgenic mice with WT to demonstrate that the cardioprotective effects of short-term caloric restriction are mediated by increased production of adiponectin and the resulting activation of AMP-activated protein kinase.

The insulin receptor knockout (IR −/− ) mouse is a genetic model of resistance to insulin's indirect effects on hepatic glucose production. This model demonstrates high levels of adiponectin in the blood with normal adiponectin receptor levels and was used to provide evidence that adiponectin potentiates hepatic insulin sensitivity. 71 Carvalho et al. 72 crossed glucose transporter-4 knockout (GLUT-4 −/− ) mice with mice overexpressing GLUT-4 only in adipose tissue (AG-4-TG). Overexpression of GLUT-4 reduces fasting hyperglycemia and glucose intolerance in GLUT-4 −/− mice to subnormal levels and reduces whole body insulin resistance without restoring glucose transport in muscle.

Adipose fatty acid binding protein knockout (A-FABP −/− ) mice have increased fat mass, decreased lipolysis, increased muscle glucose oxidation, and attenuated insulin resistance. Mice overexpressing epithelial FABP in adipose tissue have the exact opposite phenotype. These observations suggest that the balance between adipocyte lipolysis and lipogenesis is remodeled in animal models that reprogram adipokine expression in fat cells and plasma adipokine homeostasis. 73 Transgenic mice that overexpress protein phosphatase-1 (PP-1) glycogentargeting subunit (PTG), driven by the adipocyte fatty acid binding protein promoter (PTG-TG), were found to have exogenous PTG in gonadal, perirenal, and brown fat depots, but not in any of the other tissues studied. PTG overexpression was associated with a modest redistribution of PP-1 to glycogen particles. The results of these experiments suggest that in vivo mechanisms may exist to maintain adipocyte glycogen storage at physiological set points. 74 Regucalcin is a multifunctional regulatory protein in intracellular signaling pathways. Female regucalcin transgenic (RC-TG) rats were compared at 7 and 50 weeks of age. As these animals age disorders of lipid metabolism in adipose tissue and liver are observed and levels of gene expression of leptin and adiponectin are reduced. 75 Hemochromatosis gene knockout (Hfe −/− ) mice have increased plasma adiponectin levels and increased activation of AMP-dependent kinase. Following glucose challenge these animals have decreased glucose excursions compared with WT controls. The decreased glucose excursions are mediated by insulin-independent increased glucose disposal. 76 Feeding a high-fat diet to low-density lipoprotein receptor knockout (LDL-R −/− ) mice results in obesity, hyperglycemia, hyperlipidemia, and upregulation of serum TNF-a . Mice with augmented vascular TNF-a , produced by a transgene (SM22-TNF-a -TG) driven by the SM22 promoter, had upregulated aortic Msx2, Wnt3a, and Wnt7a transcription proteins that contribute to the aortic calcification seen in type-II diabetic mouse models. 77 Infusion of a large number of CD4+ helper T (Th) cells overcomes ovalbumin (OVA)-specific immune tolerance in transgenic rat insulin promoter (RIP)-mOVA mice. This results in CD+ cytotoxic T lymphocyte-mediated destruction of pancreatic islet cells and diabetes. Major histocompatibility complex (MHC) gene knockout (MHC-II −/− ) mice lack CD4+ T cells. When CD4+ Th cells are injected into MHC-II −/− mice the OVA-specific CD8+ T-cell response is stimulated. These findings could have significant implications in autoimmunity, antitumor immunity, and regulatory T-celldependent immune suppression, important in xenotransplantation studies. 78

Research in xenotransplantation is directed at solving the ever-increasing shortage of organs for human transplantation. It also offers new information related to the development of cell-and tissue-based therapies. Real progress in xenotransplantation has been delayed by the presence of xenoreactive natural antibodies that bind to the foreign cell surface and activate complement resulting in graft rejection. Genetic engineering of donor cells and animals to express human complement inhibitors such as hCD59 has significantly prolonged graft survival. Expression of human a , 2-fucosyltransferase (HT) in pigs modifies the cell-surface carbohydrate phenotype and results in reduced G-a -1, 3-Gal expression and decreased antibody binding. Hearts from transgenic pigs that coexpress hCD59 and HT were perfused with human blood. These hearts demonstrated increased resistance to human serummediated lysis. 79 Targeting xenograft rejection using single genetic modifications has proven to be ineffective. This led to development of pigs that express human decay accelerating factor (hDAF). Hearts from hDAF transgenic pigs seem to be protected during perfusion with human blood or blood components. They are metabolically stable and maintain acceptable hemodynamic function longer than previous models. 80 -83 Expression of human complement regulating factor (hCRF) in pig organs seems to prevent hyperacute rejection of these organs after xenotransplantation to nonhuman primates. Arteries from pigs transgenic for human CD46 expression demonstrate augmented endothelium-dependent relaxation responses to bradykinin mediated by the release of endothelium-derived relaxing factors other than NO. 84 Pigs transgenic for human membrane cofactor protein (hMCP) were crossed with pigs heterozygous for hDAF. Endothelial cells from this cross were exposed to complement-mediated damage. Cells expressing both hMCP and hDAF were not better protected than cells expressing only hDAF. 85 Transgenic CMy-mOVA mice were subjected to adoptive transfer of OVA-specific CD8+ effector T cells expressing OVA in cardiac myocytes. The studies conducted on these animals indicate that granulocytic inflammation sustains CD8+ T-cell-mediated myocarditis. This is important knowledge related to allograft rejection. 86 Hearts from transgenic mice expressing viral interleukin (vIL-10), encoded in the Epstein-Barr virus genome, were transplanted as vascularized allografts into unmodified MHC full-mismatched or MHC class II-disparate mice. Results from these studies indicate that a high level of expression of vIL-10 in grafts can exacerbate immunological rejection. 87 Liver sinusoidal endothelial cells are capable of selectively suppressing the expansion of IFN-g -producing cells but are also capable of promoting the outgrowth of IL-4-expression in T helper (Th) cells thus creating an immune suppressive milieu in the liver. 88 Donor hearts from B6.C-H2 mice were transplanted into WT and IL-10 transgenic recipients. In IL-10 TG recipients murine IL-10 is produced under control of the human IL-2 promoter. IL-10 expression inhibited the development of allograft vasculopathy. 89 Hearts from IL-4 transgenic mice, under the control of a cardiac a -myosin heavy chain promoter, were transferred into unmodified recipients. Although the investigators were able to establish that Th-2 bias may contribute to allograft acceptance in this model, probably by inducing the down-regulation of Th-1-cytokine mRNAs, they were not able to conclude that those reactions were able to confer long-term graft survival. 90 Two lines of transgenic mice express b -galactosidase ( b -gal) exclusively in endothelial cells (EC). TIE2-lacZ mice express b -gal in all EC and VWF-lacZ mice express b -gal only in the microvascular EC of the heart and brain. Using these animal models Rothermel et al. 91 found that EC express intracellular "self" proteins to the immune system but this antigen expression does not delete or stimulate a large population of specific lymphocytes that respond to the same protein following conventional immunization with protein or expression vector DNA. The results of these experiments indicate that context sensitivity in the immune recognition of EC exists and that this phenomena needs to be considered in the context of xenotransplantation.

Studies on transgenic mice overexpressing canine cardiac Na + /Ca 2+ exchanger (cNCX) indicate that this exchanger could be an important Ca 2+ transport mechanism in myocardial dysfunction. During ischemia-reperfusion injury increased [Ca 2+ ] in the sarcoplasmic reticulum, the result of increased Na + /Ca 2+ exchange activity, can compromise contractile performance and result in cardiac hypertrophy and heart failure. 92 The NCX gene contains at least three promoters, H1, K1, and Br1, resulting in multiple tissue-specific variants of the NCX. The H1 promoter directs cardiacspecific expression of NCX in both the embryo and adult and is probably responsible for upregulation of cNCX in response to pressure overload. 93 Postrest potentiation was compared in transgenic mice overexpressing cNCX and mice with a deletion mutant of cNCX (Delta680-685). The Delta680-685 mice are devoid of intracellular Na + -and Ca 2+ -dependent regulatory properties. Postrest potentiation was greater in Delta680-685 mice than in the cNCX animals indicating that ionic regulation of sodium/calcium exchange plays a significant functional role in myocardial contractility. 94 Other studies using isolated myocytes from the same models suggest that beat-to-beat changes in cNCX function can occur in vivo. 95 Overexpression of cNCX in isolated myocytes from transgenic mice appears to accelerate the decline of [Ca 2+ ]i during relaxation. Increased Ca 2+ influx also appears to occur. 96 Null mutation of the cNCX gene is lethal resulting in embryonic death (9.0-9.5 days). When transgenic mice expressing canine cNCX were bred to cNCX +/− mice this did not prevent the lethal results. 97 Isolated thoracic aortic rings from transgenic mice that specifically overexpress NCX in smooth muscle were used to show that NCX was involved in the forskolin-induced reduction of tension resulting from decreased [Ca 2+ ]i. 98 The reverse NCX current was measured in isolated ventricular myocytes from WT and transgenic mice overexpressing NCX. Currents were significantly higher (>twofold) in the transgenic myocytes. 99 Transgenic mice that overexpress the human sarcolemmal Na + /H + exchanger (hNHX), with high cardiac activity, develop hypertrophy, contractile dysfunction, and heart failure. These changes are mainly the result of activation of calmodulindependent protein kinase-II (CaMK-II)-dependent phorphorylation of phospholamban (PLB ). 100

Several laboratories have reported the results of experiments using transgenic mice overexpressing cardiac-specific TNF-a or b using a variety of different strategies and/or promoters. 101 -107 These animals develop concentric ventricular hypertrophy, 101 , 102 modify desmin so that it loses its intercalated disk localization and forms aggregates that colocalize with heat shock protein 25 and ubiquitin, 106 and demonstrate atrial structural remodeling, downregulation of connexin-40, and an increased incidence of atrial arrhythmias. 104 Sekiguchi et al. 105 were able to demonstrate that overexpression of TNF-b signaling pathways suppresses PPAR-a activity and reduces cardiac fatty acid b -oxidation in cardiac myocytes. Increased matrix metalloproteinase (MMP)-3 in male TNF-a transgenic mice might regulate activation of MMP-9/gelatinase initiating the progression of cardiac remodeling and the development of heart failure. 103 Sustained proinflammatory signaling in the hearts of adult transgenic mice overexpressing TNF-b is associated with a profibrotic phenotype that activates Smad 2/3 leading to increased myocardial fibrosis and loss of compliance in the left ventricle. 107 Transgenic mice with murine IL-10 under the control of the human IL-2 promoter fed a high-fat diet demonstrate decreased atherosclerotic lesions compared with WT controls. 108 Overexpression of IL-10 by T cells inhibits atherogenesis in LDLR −/− mice fed a high-fat diet. 109 Willuweit et al. 110 generated transgenic mice expressing a noncleavable transmembrane form of TNF under control of the endothelial-specific tie2 promoter. These mice develop chronic inflammatory disease in kidney and liver but were protected from immune-mediated liver injury following Con A-induced acute hepatitis. Interferon-g transgenic mice constitutively express IFN-g in their livers and therefore have high circulating serum levels and develop chronic active myocarditis. 111 LPS-induced toxicosis is characterized by hypermetabolism and anorexia in mice. TNF-a −/− mice show a reduction in the amount of LPS-induced hypermetabolism but no change in anorexia. Lymphotoxin-a −/− mice show the same responses to LPS as the TNF-a −/− mice. Results from experiments using soluble tumor necrosis factor receptor-1 fusion protein (TNFR1-IgG −/− ) transgenic mice indicate that the hypermetabolic and anorexic responses are independently regulated. Interferon-g receptor knockout mice showed the strongest anorexic response following LPS exposure. 112 TNF-a −/− mice show a reduction in reactive stenosis following endothelial injury. 113 Intercellular adhesion molecule-1 knockout (ICAM-1 −/− ) mice were subjected to myocardial ischemia and reperfusion at 2 h, 1 week, and 3 weeks. The absence of ICAM-1 expression was associated with less myocardial damage following early reperfusion but the size of the infarction or scar formation was not changed. 114 b -1integrin knockout ( b -1 −/− ) mice subjected to myocardial ischemia-reperfusion injury demonstrated reduced neutrophil infiltration in the ischemic regions but there was no effect on the severity of myocardial damage. 115

Peroxisome proliferator-activated receptor (PPAR) alpha (PPAR-a ) is a key driver of diabetes-related lipid metabolic dysregulation. Transgenic mice overexpressing PPAR-a (PPAR-a -TG) have decreased GLUT-4 mRNA levels and decreased glucose uptake. 116 PPAR-a -TG mice also demonstrate reduced b -adrenergic responses in contractility and chronotropy compared with WT controls. 117 Electrophysiological experiments conducted on myocytes from both the left and right ventricles of PPAR-a -TG and WT control mice reveal marked K + current remodeling in the mice overexpressing PPAR-a . 118 DOCA-salt hypertension was induced in WT controls and PPAR-a −/− mice. These studies reveal that the PPAR-a pathway induces renal tubular 20-hydroxyeicosatetranenoic acid (20-HETE) production regulating Na + retention and blood pressure. 119 The Na + and blood pressure regulation in PPAR-a −/− mice is also affected via amiloride-and thiazide-sensitive mechanisms, so this model is not hypertensive but develops salt-sensitive hypertension despite defective fatty acid oxidation. 120 Transgenic mice expressing PPAR-g 1 in the heart, via the cardiac a -myosin heavy chain promoter, have increased cardiac expression of fatty acid oxidation genes and increased lipoprotein triglyceride uptake. Heart glucose gransporter-4 (GLUT-4) mRNA expression and glucose uptake are not decreased. These animals develop DCM associated with increased lipid and glycogen stores, and abnormal ultrastructural changes in the mitochondria and cristae. Loss of PPAR-g in myeloid cells impairs alternative macrophage activation and predisposes PPAR-g −/− mice to the development of diet-induced obesity, insulin resistance, and glucose intolerance. 121

Transgenic mice overexpressing angiotensinogen have decreased caspase recruitment domain (ARC), catalase expression, and protein kinase-2 (CK-2) levels. Catalase, CK-2, and ARC are an antihypertrophic pathway in the heart. 122 Transgenic mice that overexpress rat angiotensinogen in their proximal tubule cells were used to demonstrate that the intrarenal renin-angiotensin system (RAS) stimulates proximal tubule cell apoptosis and tubulointerstitial fibrosis, at least in part, by enhanced NADPH oxidase activity and ROS generation independent of hypertension. 123 Double-transgenic rats harboring both human renin and human angiotensinogen genes were compared with Sprague-Dawley normal controls in experiments with and without a p38 inhibitor. The p38 mitogen-activated protein kinase inhibitor improved survival, target organ damage, and arrhythmogenic potential in these double-transgenic rats. 124 Angio-II subtype 1A receptor (ATR-1A) −/− and WT mice were subjected to 2K1C renovascular hypertension and were compared. Arterial blood pressures were significantly lower in the ATR-1A −/− mice. Clip placement, ATR-2 blockade, and NOS activity did not alter the hypertension in this knockout model. 125 , 126 

Myocardial eNOS and mitogen-activated protein kinases (MAPK), including ERK, p38, and JNK, protein expression were measured in bradykinin-2 receptor (BR-2) knockout (BR-2 −/− ) mice. Disruption of BR-2 resulted in maladaptive cardiac hypertrophy with downregulation of eNOS and upregulation of MAPK. These results were reversed by treatment with a NOS inhibitor. 127 BR-2 −/− and their normal 129/SvEvTac WT controls were compared to evaluate the hypertensive effects of DOCA-salt and aortic coarctation. In this model kinins, acting via B-2 receptors, do not participate in the maintenance of normal arterial pressures or the establishment and maintenance of hypertension resulting from either treatment. Both BR-2 −/− and WT mice reacted similarly to DOCA-salt and aortic coarctation when treated with angiotensin-converting enzyme inhibition, i.e., hypertension and ventricular hypertrophy were prevented. 128 However, Madeddu et al. 129 used BR-2 −/− and WT to conclude that kinins, acting on the BR-2, exert protection against excessive hypertension in the early phases of 2K1C.

Apolipoprotein-E (ApoE −/− ), C57BL/6 WT, and sham-operated mice were compared following 2K1C renovascular hypertension. ApoE −/− mice developed less of an increase in aortic wall area than that seen early in the WT controls but the aortic lumen area was increased to a similar magnitude in both 2K1C models. 130 The effects of 1K1C and 2K1C renovascular hypertension were compared in ApoE −/− mice. 2K1C animals developed significantly more atherosclerotic lesion area and enhanced accumulation of macrophages, accompanied by a parallel increase in scavenger receptor-A expression in the macrophages, in the aortic sinus than did the 1K1C mice. This suggests that increased generation of Angio-II in the 2K1C model may initiate and promote atherosclerosis via activation of VSMC. 131 When ApoE −/− mice were fed a high-fat diet and subjected to 2K1C renovascular hypertension they were unable to increase renin secretion and blood pressure in response to diminished renal perfusion compared with ApoE −/− mice fed a regular diet. 132 ABCG1 is a member of the G subfamily of ATP-binding cassette (ABC) transporters. Overexpression of ABCG1 alone can induce cholesterol efflux to HDL. When bone marrow from ABCG1 −/− mice is transplanted into ApoE −/− or LDL −/− mice the amount of atherosclerotic lesion developed is reduced. ABCG1 −/− mice were crossed with LDL −/− mice and the offspring (ABCG1/LDL −/− ) were compared with LDL −/− mice after both were placed on a high-fat diet. No major differences were observed in total plasma lipids but IDL-LDL cholesterol was significantly increased in the double-knockout mice as was the amount of atherosclerotic lesions. Plasma levels of MCP-1 and TNF-a were also increased in the double-knockout mice. 133 BACH-1 is a nuclear protein that directly interacts with the highly conserved C-terminal BRCT repeats of the tumor suppressor BRCA-1. BACH-1/ApoE −/− (double knockout) mice were generated by crossing BACH-1 −/− and ApoE −/− mice. These mice were fed a high-fat diet for 8 weeks. The double-knockout mice had significantly less atherosclerotic lesion formation, a result of upregulation of heme oxygenase-1 in the endothelium and, to a lesser extent, in the vascular smooth muscle. 134 Mice transgenic for lysozyme (LZ-TG) are resistant to both acute and chronic oxidative stress. They display decreased circulating levels of pro-oxidant advanced glycation end products (AGEs). The degree of atherosclerosis was evaluated in LZ-TG mice crossed with ApoE −/− mice (LZ/ApoE −/− ). Serum levels of LZ were increased, levels of AGE and 8-isoprostanes were decreased, but hyperlipidemia was similar to ApoE −/− controls. The LZ/ApoE −/− transgenic mice had significantly less atherosclerotic plaque, neointimal lesions, and inflammatory infiltrates than the controls, and femoral arterial lesions following injury were also reduced. 135

Two strains of toll-like receptor TLR-4 −/− mice (C57/BL10 ScCr and C3H/HeJ) were compared with control strains (C57/BL10 ScSn and C3H/OuJ). All four groups were subjected to 1 h of coronary ligation followed by 24 h of reperfusion. The TLR-4 −/− animals had less infarcted area, less neutrophilic infiltration, less myeloperoxidase activity, and fewer lipid peroxides and complement deposition than controls. 136 TLR-4 −/− mice demonstrate improved left ventricular function and reduced LV remodeling following coronary ischemia-reperfusion injury than WT controls. 137 When TLR-2 −/− mice were compared with WT controls, following coronary ischemia-reperfusion injury, survival rates were significantly higher in the TLR-2 −/− mice but infarct size and degree of inflammatory cell infiltration were similar. There were significantly less myocardial fibrosis, TGF-b , and collagen type-I mRNA expressions in the noninfarct area of the knockout mice. 138 The same laboratory found that inflammatory responses and neointimal hyperplasia were reduced in TLR-2 −/− mice following the placement of an external cuff around the femoral artery. 139

Ectonucleoside triphosphate diphosphohydrolase-1 (CD39) is a plasma membrane ectoenzyme that regulates purinergic receptor signaling by controlling the levels of extracellular nucleotides. Using Cav-1 −/− mice Papanikolaou et al. 140 demonstrated that caveolae are not essential for the enzymatic activity of CD39 or for its targeting to plasma membrane. Cav-1 TG mice that overexpress Cav-1 show that endothelialspecific expression of Cav-1 impairs endothelial NOS activation, endothelial barrier function, and the angiogenic response to exogenous VEGF and ischemia. VEGF-mediated phosphorylation of Akt and eNOS were significantly reduced in Cav-1 TG mice compared WT littermates. 141

Transgenic rabbits that lack slowly activating delayed rectifier K + currents (IKs), designated LQT-1 (long QT-1), and another rabbit model that generates repolarizing K + currents (IKr) (long QT-2) 142 have been generated. These TG rabbits were produced by expression of pore mutants of the human genes designated KCNQ1 (KvLQT1-Y315S) and KCNH2 (HERG-G628S) in the heart. Both TG rabbits demonstrate prolongation of the QT interval and prolonged action potentials associated with the elimination of IKs and IKr currents. In these animals the elimination of one repolarizing current was associated with downregulation of the reciprocal repolarizing current. This is different from the compensatory upregulation that has been observed in long QT syndrome (LQTS) mouse models. 143 -145 

Mice expressing a luciferase reporter, whose transcription is dependent upon nuclear factor kappa-B (NF-k B) activation, were studied after myocardial infarction. A significant increase in NF-k B activity was observed with the maximum response 3 days following infarction. 146 Mice with NF-k B subunit p50 knocked out (p50/ NF-k B −/− ) were compared with WT controls following coronary artery ligation and ischemia-reperfusion injury. Ventricular dilation, early mortality, and ischemiareperfusion injury were significantly reduced in the p50/NF-k B −/− animals compared WT controls. 46 , 147 , 148 Pharmacological inhibition of aldose reductase, or knockdown of the enzyme by small interfering RNA, prevents the activation of NF-k B and the release of TNF-a and increased survival in mice injected with lethal doses of LPS. 149 Transgenic Cre/lox mice with endothelial cell-restricted NF-k B super-repressor IkappaBalphaDeltaN (Tie-1-DeltaN) overexpression were subjected to hypertension by feeding a high-salt diet and l -NAME plus infusion of Angio-II. Both Tie-1-DeltaN and control mice demonstrated equal levels of hypertension. Tie-1-DeltaN mice developed less renal injury, reduced inflammatory responses, and less albuminuria than controls. There was also a significantly reduced expression of ICAM-1 and VCAM-1, targets of NF-k B. The investigators concluded that in vivo NF-k B suppression in endothelial cells blocks a signaling cascade leading to reduced hypertension-induced renal damage in the face of hypertension. 150 A20 was first described as a TNF-inducible gene in human umbilical vein endothelial cells that inhibits NF-k B signaling and protects against apoptosis, inflammation, and cardiac hypertrophy. Transgenic mice containing the human A20 gene, under the control of the a -myosin heavy chain promoter, exhibit cardiacspecific overexpression of A20. Following acute coronary artery ligation these mice have improved cardiac function and less cardiac remodeling, apoptosis, inflammation, and fibrosis than controls. 151

Orphan nuclear receptors, ERR-a and ERR-g , act as nonobligatory heterodimers and target a common set of promoters involved in energy substrate uptake, the production and transport of ATP across mitochondrial membranes, intracellular fuel sensing, Ca 2+ handling, and myocardial contractility. 152 Disruption of the ERR-g gene, highly expressed in fetal and postnatal hearts of mice, results in lactatemia, cardiac arrhythmias, and mortality during the first week of life. 153 Steroid receptor coactivator-1 (SRC-1) is a transcriptional coactivator for nuclear receptors including estrogen receptors (ER). SRC-1 −/− mice were used in studies to demonstrate that SRC-1 is expressed in endothelial cells, VSMC, and neointimal cells. Neointimal growth, induced by injury to the common carotid artery, was almost completely inhibited by estrogen in WT mice but only partially inhibited in the SRC-1 −/− mice.

Troponin T (TnT) is essential to the Ca 2+ regulatory system of striated muscle. Three specific fiber-type TnT genetic isoforms encoding cardiac, slow-and fasttwitch skeletal muscle have been identified. Intact cardiac muscle strips from transgenic mice overexpressing fast-twitch skeletal muscle TnT show decreased contractility at acidic pH than the same preparations from WT control mice. 154 Transgenic mice that overexpress cardiac troponin-I (TnI) have serine residues normally targeted by protein kinase A (PKA) that are mutated to aspartic acid and mimic constitutive phorphorylation. These animals have slightly enhanced basal systolic and diastolic left ventricular function but display a marked increase in frequency-dependent inotropy and relaxation compared with control mice. 155 Hemodynamic studies were conducted in mice that express normal levels of PLB and express either cardiac troponin-I (PBL/cTnI) or the slow skeletal isoform of TnI (PBL/ssTnI). The latter cannot be phosphorylated by PKA. Another construct of mice that do not express PBL and express either cTnI (PBL −/− /cTnI) or ssTnI (PBL −/− /ssTnI) was also studied. PBL/ssTnI hearts demonstrated a significant reduction in -dP/dt compared with PLB/cTnI hearts. b -adrenergic stimulation increased HR similarly in both groups but at the highest levels of stimulation -dP/ dt was significantly less in PLB/ssTnI than in PLB/cTnI hearts. The authors concluded that phosphorylation of cTnI significantly contributes to the enhanced rate of left ventricular relaxation during b -adrenergic stimulation. 156

Genetic ablation of the chromogranin A ( Chga −/− ) gene in mice results in hypertension, reduced myocardial function, and reduced responses to b -adrenergic and ET-1 stimulation. Pretreatment of Chga −/− mice with catestatin (human chromogranin A352-372) prevents the adverse effects of removing this gene. 157 , 158 

ATR-1 activation upregulates the expression of lectin-like oxidized low-density lipoprotein receptor LOX-1. LOX-1 activation upregulates ATR-1 expression. Angio-II-induced hypertension, but not NE-induced hypertension, was attenuated in LOX-1 −/− mice. This indicates that LOX-1 is a key modulator of Angio-IIinduced hypertension and cardiac remodeling. 159 LOX-5 −/− mice were used to demonstrate that the loss of this receptor has no effect on cardiac ischemia-reperfusion injury, but neutrophil infiltration and TNF-a expression were greater in the LOX-5 −/− animals. 160 Junctin Junctin (JCN) is a transmembrane protein located in the cardiac junctional sarcoplasmic reticulum (SR). It binds to the ryanodine receptor [calsequestrin (CSQ)] and to triadin-1. Atria from 3-week-old transgenic mice that overexpress junctin (JCN-TG) demonstrate reduced expression of triadin-1. This results in a higher SR Ca 2+ load but no changes in contractility or HR. Atria from 6-week-old JCN-TG show a compensatory downregulation of the ryanodine receptor that seems to offset the effects of junctin overexpression. In 18-week-old JCN-TG the progressive decrease in ryanodine receptor density seems to contribute to decreases in atrial contractility and HR during stress. 161 JCN-TG mice demonstrate impaired myocardial relaxation possibly as a result of reduced NCX expression and/or increased leak of SR Ca 2+ . Altered shortening-frequency excitation-contraction coupling in these animals may be a consequence of impaired excitation-contraction coupling with depressed SR Ca 2+ release at higher stimulation rates. 162 Transgenic mice overexpressing canine junctin also show changes in the packing of CSQ in the junctional SR and a facilitation of the association of SR and T tubules. 163 Crossbreeding of mice with heart-specific overexpression of both triadin and junctin resulted in offspring (JxT-TG) with a stable threefold expression of total triadin but normal levels of junctin. These animals display cardiac hypertrophy, prolonged basal relaxation, depressed responses to b -adrenergic stimulation, and altered Ca 2+ transients. 164 

Connexins (Cx) are labeled with a number that represents the molecular mass of the amino acid sequences, in kDa. When identical connexin isotypes form both Connexins of a gap junction a homomeric gap junction channel is formed. When different connexin isotypes combine a heteromeric channel is produced. In the mammalian heart seven connexins have been identified: Cx37, Cx40, Cx43, Cx45, Cx46, Cx50, and Cx57. The Cx40 −/− mouse has been used to study mechanisms of arrhythmogenesis. 165 , 166 Aside from being components of gap junctions, connexins can also comprise large, nonselective pores known as hemi channels. The Cx30.3/lacZ transgenic approach was used to identify Cx30.3 in the renal medulla in mice, rats, and rabbits. 167 Cx45 expression has been found in the juxtaglomerular apparatus (JGA), as well as in the heart. Transgenic mice that express lacZ coding DNA under the control of the Cx45 promoter were used to discover that Cx45 is involved in the propagation of JGA vascular signals and thus in the regulation of renin release and the control of blood pressure. 168 Cx40 −/− mice have a misdirection of renin-expressing cells from the medial layer of afferent arterioles to the perivascular tissue, extraglomerular mesangium, and periglomerulular and peritubular interstitium. The aberrant renin-producing cells in these animals also express significant amounts of COX-2 mRNA and this, apparently, contributes to the renin secretion. 169 Cx40 −/− mice were also used to show that renin-secreting cells are coupled to each other and to endothelial cells by Cx40containing channels. 170 Transgenic mice were produced in which the coding region for Cx43 was replaced by Cx26. Both neonatal and adult Cx43 knock-in Cx26 mice demonstrated slowed ventricular conduction patterns, and both males and females were infertile from impaired gametogenesis. 171 Calrectin is a Ca 2+ -binding protein of the endoplasmic reticulum and plays an essential role in cardiac development. Cre-loxP transgenic mice with spatiotemporal overexpression of calrectin were created. Protein levels of Cx40, Cx43, and myocyte-enhancer factor-2C were lower than the level of these proteins in control hearts. 172 The overexpression of calrectin and decreased levels of Cx were associated with arrhythmias, ventricular dilatation, and sudden death in 6-10-week-old offspring, and marked edema at 7 weeks of age. The expression of hyperpolarization-activated cyclic nucleotide-gated channel-1, an essential component for cardiac pacemaker activity, was also decreased in the hearts of these mice.

Mouse studies have shown that PLB is a key regulator of SR Ca 2+ cycling and cardiac function but mice differ significantly from humans in how they regulate calcium. Rabbits have proven to be a better model for the study of calcium handling. Transgenic rabbits that overexpress PLB die early from severe skeletal muscle wasting and myocardial dysfunction. A viable transgenic line exhibiting only a 30% increase in cardiac PLB shows isolated foci of cardiac pathology but cardiac function and response to b -adrenergic stimulation are normal. 173 PLB phosphorylation is a CaMKII-dependent process. Mice with transgenic overexpression of CaMKII-delta-C (chronic overexpression) develop heart failure with impaired SR Ca 2+ loading during late acidosis compared with WT controls. This response may be associated with decreased SR Ca-ATPase and decreased PLB expression. However, adenovirus-mediated gene transfer of CaMKII-delta-C in isolated mouse and rabbit cardiomyocytes (acute overexpression) actually slightly improves recovery following increased SR Ca 2+ loading during late acidosis. 174

Fas ligand (FasL) is a potent proapoptotic type-II transmembrane protein. Its forced expression can induce a dramatic inflammatory response. 175 Transgenic mice with cardiac-specific expression of soluble Fas (sFas), a competitive inhibitor of FasL, were injected with either LPS or control vehicle. Neutralization of FasL by expression of sFas significantly preserved cardiac function and reduced inflammatory responses to LPS in the heart. 176 Mice with cardiac-specific expression of sFas and double homozygous TG mice that express both monocyte chemoattractant protein-1 (MCP-1) and sFas were used to show that FasL released from infiltrating monocytes plays a critical role in the adverse effects of MCP-1 expression. The results suggest that Fas/FasL signaling could be a novel therapeutic target for certain types of heart failure. 177 , 178 

A novel class of protease-activated receptors (PARs) characterized by seven transmembrane G-protein-coupled domains are activated by serine proteases such as thrombin, trypsin, and tryptase. PAR-1, PAR-2, and PAR-4 have been implicated in vascular development via studies using transgenic mice and synthetically tethered ligand domains. 179 PAR-4 −/− mice have prolonged bleeding times because of the lack of PAR-4 function in platelets and are thereby protected against thrombosis. 180 Male PAR-2 −/− mice have a moderate elevation of systolic arterial and pulse pressures, but no change in diastolic pressures along with a lack of hypertensive response to high-salt diet. This model displays only a subtle difference in the time course of hypertension in response to Angio-II infusion. 181 Extravascular inflammation was induced by injection of recombinant soluble murine tissue factor (TF) in the hind paw of PAR-1 −/− , PAR-2 −/− , PAR-3 −/− , and PAR-4 −/− mice. There was no effect on the inflammatory response in PAR-1 −/− , PAR-2 −/− , or PAR-3 −/− mice but the PAR-4 −/− mice demonstrated significantly less soluble TF (sTF)-induced swelling of the injected paw. These results indicate that sTF induces inflammation via a thrombin-dependent pathway, and both fibrin deposition and platelet activation are essential steps with the activation of PAR-4 essential to the process. 182 Corin is a transmembrane serine protease that has been isolated from the heart. It is responsible for converting proatrial natriuretic peptide (pro-ANP) to active ANP. Corin −/− mice do not convert pro-ANP to ANP resulting in salt-sensitive hypertension. Interestingly the hypertension is exacerbated in pregnant corin −/− mice. 183 Matrix metalloproteases (MMPs) are enzymes that regulate matrix remodeling in response to hypertension. Transgenic mice that overexpress cardiac MMP-1 and matched WT were subjected to hypertension induced by suprarenal banding of the aorta. Overexpression of MMP-1 attenuated the development of myocardial fibrosis, prevented left ventricular dilatation, and preserved myocardial function. 184 Transgenic rabbits that overexpress human matrix metalloproteinase-12 (hMMP-12-TG) were fed a 1% cholesterol diet for 6 weeks. They developed larger atherosclerotic plaques, more significant degradation of the aortic internal elastic layer, and increased numbers of infiltrating macrophages and smooth muscle cells into the atherosclerotic lesions than WT control rabbits. 185 Tissue inhibitor of metalloprotease-3 (TIMP-3) inhibits MMP and regulates angiogenesis. TIMP-3 −/− mice demonstrate enhanced MMP activity in the retinal choroids and develop abnormal vessels with dilated capillaries. 186 Strain differences are demonstrated between FVB and B6 mice where disintegrin and metalloproteinase-17 (ADAM-17) mRNA expression is higher in the liver, macrophages, and aorta in FVB.LDLR −/− mice than in B6.LDLR −/− mice. Macrophages from FVB.LDLR −/− mice demonstrate fivefold increases in PMAinduced shedding of TNF-a and 32% increases in release of TNF-receptor-I than B6.LDLR −/− animals. 187 The copper transporter Menkes ATPase (MNK) is overexpressed in MNKmutant mice. This model was used to demonstrate that MNK plays an important role in modulating Angio-II-induced hypertension and endothelial function by regulating extracellular superoxide dismutase (SOD-3) activity and vascular superoxide production. 188

P2X4R is a ligand-gated ion channel. When activated by extracellular ATP it allows Ca 2+ influx. Transgenic cardiac overexpression of human P2X4R results in increased ventricular contractility. Transgenic mice with cardiac overexpression of canine CSQ have ventricular hypertrophy, heart failure, and early mortality. Crossing P2X4R-TG with CSQ-TG produced CSQ/P2X4R-TG offspring with prolonged survival, less ventricular hypertrophy, and restored b -adrenergic responsiveness. 189

ANP −/− mice received either vehicle or an Angio-II type-2 receptor (ATR-2) antagonist. Both groups were placed on a high-salt diet. The studies indicate that ATR-2 blockade in salt-sensitive hypertensive/ventricular hypertrophic ANP −/− mice results in changes in myocardial extracellular matrix components that translate into decreased ventricular hypertrophy. 190

Homozygous osteopetrotic mice (Op/Op) are deficient in macrophage colonystimulating factor (M-CSF). Adult Op/Op, heterozygous (Op/ + ), and WT mice were subjected to 14 days of Angio-II (1,000 ng/kg/min) or vehicle infusion. Op/Op mice demonstrated less endothelial dysfunction, less vascular remodeling, and less oxidative stress than WT. 191 M-CSF has also been shown to stimulate differentiation and proliferation of monocyte/macrophage lineage and is involved in neointimal formation following vascular injury. Recombinant human M-CSF (500 m g/kg/day) or vehicle was administered for 10 consecutive days, starting 4 days prior to mechanical injury to the femoral artery, in C57BL/6 mice. M-CSF accelerated early neointimal formation after vascular injury suggesting that inhibition of this system might have therapeutic potential in the treatment of a number of cardiovascular diseases. 192

Endothelin-1 (ET-1) is a potent endogenous vasoconstrictor that contributes to vascular remodeling in hypertension and other cardiovascular diseases. Amiri et al. 193 targeted expression of the human pre-pro-ET-1 gene to the endothelium using the Tie-2 promoter in C57BL/6 mice. Compared with WT littermates the TG mice exhibited threefold higher vascular tissue ET-1 mRNA and sevenfold higher ET-1 plasma levels, but there was no significant difference in blood pressures between the two groups. Higher ET-1 levels resulted in structural remodeling and endothelial dysfunction in resistance vessels. The experiments conducted suggest a direct, nonhemodynamic, effect of ET-1 on the vasculature involving activation of vascular NADPH-oxidase.

Aryl hydrocarbon receptor (AHR) knockout (AHR −/− ) mice develop cardiac hypertrophy of unknown origin. When AHR −/− mice were exposed to a modest decrease in inspired pO 2 they became hypoxic and hypertensive and plasma ET-1 levels were significantly increased. The hypertension was not associated with increased pulmonary pre-pro-ET-1 mRNA expression. 194

Mice harboring targeted deletion of the elastin ( ELN ) gene (ELN +/− ) show many of the same features of supravalvular aortic stenosis (SVAS) seen in humans, including changes in cardiovascular hemodynamics and arterial wall structure. ELN +/− mice are hypertensive at birth compared with WT counterparts. The inner diameters of arteries from ELN +/− mice are smaller at any given intravascular pressure than that of WT mice. 195 , 196 Exact modeling of SVAS and other elastin gene abnormality diseases in mice is difficult because of structural differences between the human and mouse genes. A humanized elastin mouse with elastin production controlled by the human elastin gene has been developed. The human elastin protein appears to interact with the mouse elastin to form functional elastic fibers. When the h-ELN is expressed in the elastin haploinsufficient background (ELN +/− ) the hypertension and cardiovascular changes are reversed. 197 a -2-Antiplasmin a -2-Antiplasmin ( a -2-AP) is the major circulating inhibitor of plasmin. Plasmin plays a significant role in the regulation of intravascular fibrinolysis. Angio-IIinduced arterial wall thickening, vascular cell proliferation, apoptosis, c-Myc, and collagen-I expression are all significantly decreased, along with perivascular fibrosis, in a -2-AP −/− mice compared to WT mice. 198 cAMP Response Element Binding Protein cAMP response element binding protein (CREB), at serine-133, regulates gene expression in the heart. The functional significance of CREB-S133 phosphorylation was studied by comparing TG mice in which a phosphorylation-resistant (CREB-S133A) mutant, containing either an intact or a mutated leucine zipper domain (CREB-S133A-LZ), was expressed in the heart. The 1-year survival of mice from two CREB-S133A-LZ (TG) lines was equivalent to non-TG littermate controls. TG CREB-S133A mice died from heart failure at about 30 weeks of age. CREB-S133A mice demonstrate altered gene expression characteristic of heart failure whereas the CREB-S133A-LZ mice did not. 199

Hearts from otherwise normal aged mice show intramyocardial lipid accumulation, reduced fatty acid and glucose oxidation, and deterioration in supplies of cardiac ATP. These changes accompany myocardial remodeling and impaired myocardial function.

Hearts from CD36 −/− mice have lower levels of intramyocardial lipids, improved mitochondrial-derived ATP production, improved myocardial function, and a blunted hypertrophic response compared with age-matched WT. This indicates CD36 is a potential mediator of these aging-associated functional, structural, and metabolic changes. 200 

Clotting factor XIII (FXIII) is a transglutaminase involved in wound healing. FXIII −/− and FXIII +/− mice suffer left ventricular rupture and die within 5 days following ligation of the left coronary artery. FXIII −/− mice receiving intravenous FXIII replacement therapy for 5 days have normal survival rates but still have adverse ventricular remodeling compared with WT controls. 201

Apelin describes a novel endogenous peptide system thought to be involved in a number of physiological processes, including cardiovascular development and function, control of fluid homeostasis, and obesity. It is also a catalytic substrate for ACE (angiotensin-converting enzyme)-2. Endogenous Apelin is essential for the maintenance of cardiac contractility during pressure overload and aging. Apelin −/− mice develop a progressive loss of cardiac contractility associated with systolic dysfunction, but without histological abnormalities, or heart failure. Pressure overload normally induces upregulation of Apelin expression in the heart, but when Apelin −/− mice were exposed to pressure-overload-induced heart failure there was no significant difference in the LV hypertrophy response compared with WT. 202

Mutations in human TBX-5, a member of the T-box transcription factor gene family, are associated with congenital cardiac septal defects and isomerism in the autosomal dominant Holt-Oram syndrome. Overexpression of TBX-5 in embryonic chick hearts inhibits myocardial growth and trabeculation and suppresses embryonic cardiomyocyte proliferation. 203

Thrombospondin-1 is a key regulator of NO signaling. It limits the angiogenic activity of NO in EC, its vasodilator activity in VSMC, and its antithrombotic activity in platelets. Thrombospondin-1 −/− or CD47 −/− mice have hyperdynamic responses to NO and improved ability to respond to ischemic stress. 204

The pronuclear microinjection method was used to introduce purified polyomavirus middle T antigen (PyMT) transgene into the chromosomes of fertilized mice ova. The transgenic positive animals were used to develop future generations by hybridization. PyMT expression in the F1 generation produced mice with venous malformations. 205 

Mice that express a full-length thrombopoietin receptor (Mpl) transgene, in the absence of other Mpl isoforms, were generated under the control of a 2-kb Mpl promoter in Mpl −/− background animals. Transgene expression was decreased during late megakaryocyte maturation. This resulted in diminished Mpl expression in platelets. Platelets exert a negative feedback on thrombopoiesis by binding and consuming thrombopoietin in the circulation via the action of Mpl. The significant reduction of Mpl protein in platelets from Mpl-TG mice results in a marked elevation of the numbers of megakaryocytes and platelets during the steady state. 206

A VEGF transgenic mouse, rhodopsin promoter, model (tro29VEGF) that mimics nonproliferative diabetic retinopathy and mild proliferative diabetic retinopathy was used to characterize early stages of concomitant vascular and neural retinal damage. Rhodopsin was detected at postnatal day (P)-5 and reached mature levels by P-15. VEGF protein expression was transient but peaked at P-10 to P-15. In tro29VEGF mice the formation of capillary beds was accelerated compared with that in WT controls. Vascular lesions were more numerous by P-28 in the TG mice. Retinal layer thinning tracked abnormal vessel growth. 207 Osteopontin Osteopontin (OPN) is a noncollagenous adhesion molecule protein identified in atherosclerotic lesions. OPN-TG and OPN-WT mice fed a 1.25% cholesterol diet for 16 weeks develop atherosclerotic lesion but the lesions in the OPN-TG mice were significantly larger. This study also showed that OPN induces fatty-streak lesion formation and inhibits IL-10 production by macrophages. 208

Atherosclerotic disease involves a host of processes including reverse cholesterol transport (RCT). RCT is a pathway for transport of cholesterol that has accumulated in the vessel wall to the liver where it can be excreted. Major constituents of RCT include HDL and apolipoprotein A-I (ApoA-I), considered acceptors, and enzymes including cholesterol acyltransferase (LCAT), phospholipid transfer protein (PLTP), hepatic lipase (HL), and cholesterol ester transfer protein (CETP). A critical portion of this process is cholesterol efflux. Accumulated cholesterol is removed from macrophages in the subintima of the vessel wall by ATP-binding membrane cassette transporter-A1 (ABC-A1), or by other mechanisms including passive diffusion, scavenger receptor-B1, caveolins, and sterol 27-hydroxylase. The cholesterol is then available to be collected by HDL and/or ApoA-I. Studies in ABC-A1 −/− mice demonstrate that disruption of ABC-A1 genes induces atherosclerosis and that proinflammatory cytokines exert atherosclerotic effects, at least partially, by impairing RCT and cholesterol efflux. 209

Mice with a targeted disruption of the KCC3 gene (KCC3 −/− ) develop neurodegeneration of the peripheral and CNS and develop hypertension similar to Andermann syndrome in humans. Data from these animals indicate that local control of vascular myogenic tone does not require KCC3. The hypertension that develops is, apparently, dependent upon increased sympathetic tone. 210

TG mice overexpressing the terminal enzyme of aldosterone biosynthesis, aldosterone synthase (AS), in cardiac tissue were developed by gene targeting with the a -myosin heavy chain promoter. When compared with WT, TG AS mRNA was increased 100fold and aldosterone concentrations were increased 1.7-fold. This increased cardiac production of aldosterone-induced major dysfunction in coronary arteries, independent of the endothelium but there were no changes in myocardial function or structure. 211

A gene disruption cassette was cloned into exon 4, and a mouse strain lacking functional cysteine and glycine-rich protein-2 (CSRP-2) (CSRP-2 −/− ) was created. CSRP-2 −/− mice have subtle alterations in cardiac ultrastructure including changes in myocardiocyte thickness and hypertrophy. 212

Transgenic mice that overexpress parathyroid hormone type-1 receptor (PTH1R) in smooth muscle have been used to demonstrate that the PTH/PTH-related protein (PTHrP)/PTH1R system is an important regulator of cardiovascular function. Unfortunately, PTHrP/TTH1R −/− mice are not viable, so this model is unavailable for study. Three weeks after the intravenous administration of either human-PTH1R or hPTH1R tagged with green-fluorescence protein there was generalized expression of both hPTH1R mRNA and protein, particularly in blood vessels, liver, heart, kidney, and CNS. PTH1R overexpression decreased blood pressure and renal tone but also decreased HR. The TG mice demonstrated marked reductions in the production of angiotensinogen in the liver and in circulating levels of both renin activity and angiotensinogen. 213

Absence of a functional vitamin D receptor (VDR), or the key activating enzyme, 25-OHD-1-a -hydroxylase (CYP27B1), in mice results in a bone and growth plate phenotype that mimics humans with congenital CYP27B1 mutations or severe vitamin D deficiency. VDR −/− mice also develop increased renin activity resulting in hypertension, myocardial hypertrophy, and increased thrombogenicity. 214

Tp −/− and WT control mice were exposed to 21 weeks of l -NAME and a 6% salt diet. Hypertension and myocardial hypertrophy were attenuated in the Tp −/− mice but renal hypertrophy and the severity of glomerulosclerosis, tubule vacuolization, and chronic inflammation of the interstitium were enhanced. 215

Mice lacking T and B cells (RAG-1 −/− ) exposed to Angio-II infusion-or DOCA-saltinduced hypertension exhibit a blunted hypertensive response and do not develop functional abnormalities of the vascular system. This result is, apparently, due to the lack of T cells. 216

Hypertension was produced by uninephrectomy and DOCA-salt in WT and TRPV-1 −/− mice. There was no difference in the level of hypertension produced between the two groups but there were significant increases in the urinary excretion of albumin and 8-isoprostane, glomerulosclerosis, renal cortical tubulointerstitial injury, nuclear antigen-positive cells, and renal monocyte/macrophage infiltration in the TRPV-1 −/− animals. 217

Negative results are also important. SERT −/− mice and rats have the same basal arterial pressures as WT controls and the same response to DOCA-salt hypertension. SERT does not seem to be involved in the regulation of arterial blood pressure. 218

CCR-2 −/− and age-matched WT control mice were infused continuously with either Angio-II (5.2 ng/10 g/min) or vehicle for 2 or 4 weeks. Angio-II infusion resulted in similar degrees of hypertension and LV hypertrophy in both strains. CCR-2 −/− mice with Angio-II-induced hypertension had significant decreases in oxidative stress, macrophage infiltration, albuminuria, and renal damage. GFR was significantly greater in CCR-2 −/− than in the WT controls. 219

Hinkel et al. 220 have shown that the retrograde infusion of embryonic eEPCs into zones of myocardial ischemia provides rapid paracrine protection against ischemiareperfusion injury. Intact pigs were subjected to 60 min of ischemia via percutaneous occlusion of the LAD. After 55 min of ischemia control eEPCs or cells transfected with thymosin b -4 (T-b -4) shRNA or T-b -4 alone were infused retrograde into the anterior interventricular vein. These studies demonstrate that the short-term cardioprotection resulting from retrograde infusion of eEPCs is, at least partially, due to T-b -4.

Naturally occurring variation in cardiovascular traits among inbred mouse strains

Targeting gene expression to endothelium in transgenic animals: A comparison of the human ICAM-2, PECAM-1 and endoglin promoters

A CD2-green fluorescence protein-transgenic mouse reveals very late antigen-4-dependent CD8+ lymphocyte rolling in inflamed venules

Reversal of renal lesions following interruption of nitric oxide synthesis inhibition in transgenic mice

Generation of a highly inducible Gal4®Fluc universal reporter mouse for in vivo bioluminescence imaging

Characterization of sinoatrial node in four conduction system marker mice

Effect of estrogen on global myocardial ischemia-reperfusion injury in female rats

Effects of dietary phytoestrogen on global myocardial ischemia-reperfusion injury in isolated female rat hearts

Genetic and pharmacologic strategies to determine the function of estrogen receptor alpha and estrogen receptor beta in cardiovascular system

Estrogen increases apoptosis in the arterial wall in a murine atherosclerosis model

Of mice and men: The many guises of estrogens

Contribution of epoxyeicosatrienoic acids to flow-induced dilation in arteries of male ERalpha knockout mice: Role of aromatase

Myocardial ischemia-reperfusion injury in estrogen receptor-alpha knockout and wild-type mice

The nuclear receptor ERR a is required for the bioenergetic and functional adaptation to cardiac pressure overload

Compromised aortic vasoreactivity in male estrogen receptor-alpha-deficient mice during acute lipopolysaccharideinduced inflammation

Estrogen receptor beta protects the murine heart against left ventricular hypertrophy

Estrogen inhibits cardiac hypertrophy: Role of estrogen receptor-beta to inhibit calcineurin

Metabolic actions of estrogen receptor beta (ERbeta) are mediated by a negative cross-talk with PPARgamma

Estrogen receptor beta mediates acute myocardial protection following ischemia

Increased mortality and aggravation of heart failure in estrogen receptor-beta knockout mice after myocardial infarction

Genomic deletion of estrogen receptors ERalpha and ERbeta does not alter estrogen-mediated inhibition of Ca 2+ influx and contraction in murine cardiomyocytes

Estrogen receptors alpha and beta mediate distinct pathways of vascular gene expression, including genes involved in mitochondrial electron transport and generation of reactive oxygen species

Gender-specific alteration of adrenergic responses in small femoral arteries from estrogen receptor-beta knockout mice

The oestrogen receptor beta contributes to sex related differences in endothelial function of murine small arteries via EDHF

Dilatory responses to estrogenic compounds in small femoral arteries of male and female estrogen receptor-beta knockout mice

Functional characterization and sex differences in small mesenteric arteries of the estrogen receptor-beta knockout mouse

Differential regulation of the inducible nitric oxide synthase geneby estrogen receptors {alpha}and {beta}

27-Hydroxycholesterol is an endogenous SERM that inhibits the cardiovascular effects of estrogen

Dos Reis AM . Impairment of the natriuretic peptide system in follitropin receptor knockout mice and reversal by estradiol: Implications for obesity-associated hypertension in menopause

Cardiac hypertrophy is associated with altered thioredoxin and ASK1 signaling in a mouse model of menopause

Lats2 is a negative regulator of myocyte size in the heart

Inhibition of vascular smooth muscle G protein-coupled receptor kinase 2 enhances {alpha}1DAR constriction

Proteasome degradation of GRK2 during ischemia and ventricular tachyarrhythmias in a canine model of myocardial infarction

Myocardial overexpression of GRK3 in transgenic mice: Evidence for in vivo selectivity of GRKs

Inhibition of glycogen synthase kinase 3 b during heart failure is protective

Blocking cardiac growth in hypertrophic cardiomyopathy induces cardiac dysfunction and decreased survival only in males

Axl mediates vascular remodeling induced by deoxycorticosterone acetate-salt hypertension

Role of maternal glucocorticoid inducible kinase SGK1 in fetal programming of blood pressure in response to prenatal diet

Ischemic preconditioning exaggerates cardiac damage in PKC-delta null mice

Myosin regulatory light chain phosphorylation attenuates cardiac hypertrophy

Increased glycogen stores due to gamma-AMPK overexpression protects against ischemia and reperfusion damage

Inhibition of experimental intimal thickening in mice lacking a novel G-protein-coupled receptor

Protective effects of exercise and phosphoinositide 3-kinase(p110alpha) signaling in dilated and hypertrophic cardiomyopathy

Role of gp91phox-containing NADPH oxidase in the deoxycorticosterone acetate-salt-induced hypertension

Renovascular hypertension by two-kidney one-clip enhances endothelial progenitor cell mobilization in a p47phox-dependent manner

Left ventricular remodeling after myocardial infarction in mice with targeted deletion of the NADPH oxidase subunit gp91PHOX

Exacerbation of chronic renovascular hypertension and acute renal failure in heme oxygenase-1-deficient mice

An analysis of the DOCA-salt model of hypertension in HO-1−/− mice and the Gunn rat

Animal models for the study of adenosine receptor function

Contractile effects of adenosine A1 and A2A receptors in isolated murine hearts

Adenylyl cyclase type V deletion increases basal left ventricular function and reduces left ventricular contractile responsiveness to beta-adrenergic stimulation

Norepinephrine modulates glutamatergic transmission in the bed nucleus of the stria terminalis

In vivo regulation of dopamine and noradrenaline release by alpha2A-adrenoceptors in the mouse nucleus accumbens

Cardiovascular effects of rilmenidine, moxonidine and clonidine in conscious wild-type and D79N alpha2A-adrenoceptor transgenic mice

Genetic alteration of the alpha2-adrenoceptor subtype c in mice affects the development of behavioral despair and stress-induced increases in plasma corticosterone levels

Control of myocardial contractile function by the level of beta-adrenergic receptor kinase 1 in gene-targeted mice

Increased pituitary vascular endothelial growth factor-a in dopaminergic D2 receptor knockout female mice

Norepinephrine induces lipolysis in beta1/beta2/ beta3-adrenoceptor knockout mice

Role of nNOS in blood pressure regulation in eNOS null mutant mice

Insulin resistance, hyperlipidemia, and hypertension in mice lacking endothelial nitric oxide synthase

Estrogen receptor-alpha and endothelial nitric oxide synthase nuclear complex regulates transcription of human telomerase

The estrogen effects on endothelial repair and mitogen-activated protein kinase activation are abolished in endothelial nitric-oxide (NO) synthase knockout mice, but not by NO synthase inhibition by N -nitro-l -arginine methyl ester

Ventilator-induced lung injury is reduced in transgenic mice that overexpress endothelial nitric oxide synthase

Overexpression of eNOS prevents the development of renovascular hypertension in mice

Production of endothelial nitric oxide synthase (eNOS) over-expressing piglets

Adiponectin and adiponectin receptors

Overexpression of human adiponectin in transgenic mice results in suppression of fat accumulation and prevention of premature death by high-calorie diet

Exacerbation of albuminuria and renal fibrosis in subtotal renal ablation model of adiponectin-knockout mice

Overexpression of adiponectin targeted to adipose tissue in transgenic mice: Impaired adipocyte differentiation

Cardioprotective effects of shortterm caloric restriction are mediated by adiponectin via activation of AMP-activated protein kinase

Adiponectin resistance exacerbates insulin resistance in insulin receptor transgenic/knockout mice

Adipose-specific overexpression of GLUT4 reverses insulin resistance and diabetes in mice lacking GLUT4 selectively in muscle

Lipid metabolism and adipokine levels in fatty acid-binding protein null and transgenic mice

Transgenic overexpression of protein targeting to glycogen markedly increases adipocytic glycogen storage in mice

Change in lipid components in the adipose and liver tissues of regucalcin transgenic rats with increasing age: Suppression of leptin and adiponectin gene expression

Increased glucose disposal and AMP-dependent kinase signaling in a mouse model of hemochromatosis

Aortic Msx2-wnt calcification cascade is regulated by TNF-alphadependent signals in diabetic ldlr−/− mice

Active CD4+ helper T cells directly stimulate CD8+ cytotoxic T lymphocyte responses in wild-type and MHC II gene knockout C57BL/6 mice and transgenic RIP-mOVA mice expressing islet beta-cell ovalbumin antigen leading to diabetes

Transgenic pigs designed to express human CD59 and H-transferase to avoid humoral xenograft rejection

Reduction of hyperacute rejection and protection of metabolism and function in hearts of human decay accelerating factor (hDAF)-expressing pigs

The hDAF exogene protects swine endothelial and peripheral blood mononuclear cells from xenoreactive antibody mediated cytotoxicity in hDAF transgenic pigs

Soluble galalpha(1,3)gal conjugate combined with hDAF preserves morphology and improves function of cardiac xenografts

Reduced fibrin deposition and intravascular thrombosis in hDAF transgenic pig hearts perfused with tirofiban

Endothelial function in pigs transgenic for human complement regulating factor

Production and characterization of a pig line transgenic for human membrane cofactor protein

Neutrophils sustain pathogenic CD8+ T cell responses in the heart

High-level expression of viral interleukin-10 in cardiac allografts fails to prolong graft survival

Immunomodulatory effects of the liver: Deletion of activated CD4+ effector cells and suppression of IFN-gamma-producing cells after intravenous protein immunization

Regulated interleukin-10 expression prevents chronic rejection of transplanted hearts

Murine interleukin 4 transgenic heart allograft survival prolonged with down-regulation of the Th1 cytokine mRNA in grafts

Endothelial cells present antigens in vivo

Sodium-calcium exchanger overexpression in the heart -Insights from a transgenic mouse model

Cardiac-specific expression and hypertrophic upregulation of the feline Na(+)-Ca(2+) exchanger gene H1-promoter in a transgenic mouse model

Functional role of ionic regulation of Na + /Ca 2+ exchange assessed in transgenic mouse hearts

Allosteric regulation of Na/Ca exchange current by cytosolic Ca in intact cardiac myocytes

Effects of overexpression of the Na+-Ca 2+ exchanger on [Ca 2+ ]i transients in murine ventricular myocytes

Partial rescue of the Na+-Ca 2+ exchanger (NCX1) knock-out mouse by transgenic expression of NCX1

Involvement of Na+-Ca 2+ exchanger in cAMPmediated relaxation in mice aorta: Evaluation using transgenic mice

Quantitation of Na/Ca exchanger function in single ventricular myocytes

Activation of Na + /H + exchanger 1 is sufficient to generate Ca 2+ signals that induce cardiac hypertrophy and heart failure

Targeted overexpression of transmembrane tumor necrosis factor provokes a concentric cardiac hypertrophic phenotype

Coxsackievirus B3 induces T regulatory cells, which inhibit cardiomyopathy in tumor necrosis factor-alpha transgenic mice

Differential expression of MMPs and TIMPs in moderate and severe heart failure in a transgenic model

Downregulation of connexin40 and increased prevalence of atrial arrhythmias in transgenic mice with cardiac-restricted overexpression of tumor necrosis factor

Inhibition of PPAR-alpha activity in mice with cardiac-restricted expression of tumor necrosis factor: Potential role of TGF-beta/Smad3

Desmin mediates TNF-alpha-induced aggregate formation and intercalated disk reorganization in heart failure

Transforming growth factor-beta receptor antagonism attenuates myocardial fibrosis in mice with cardiac-restricted overexpression of tumor necrosis factor

Interleukin-10 blocks atherosclerotic events in vitro and in vivo

Overexpression of interleukin-10 by activated T lymphocytes inhibits atherosclerosis in LDL receptor-deficient mice by altering lymphocyte and macrophage phenotypes

Chronic inflammation and protection from acute hepatitis in transgenic mice expressing TNF in endothelial cells

Interferon-gamma induces chronic active myocarditis and cardiomyopathy in transgenic mice

Differential roles of tumor necrosis factor-alpha and interferon-gamma in mouse hypermetabolic and anorectic responses induced by LPS

Tumor necrosis factor-alpha plays an important role in restenosis development

Mouse model of myocardial remodelling after ischemia: Role of intercellular adhesion molecule-1

Myocardial ischaemia-reperfusion injury in haematopoietic cell-restricted {beta}1 integrin knockout mice

Cardiomyocyte expression of PPARgamma leads to cardiac dysfunction in mice

Interaction between PPARA genotype and betablocker treatment influences clinical outcomes following acute coronary syndromes

PPARalpha-mediated remodeling of repolarizing voltage-gated K + (kv) channels in a mouse model of metabolic cardiomyopathy

Colfibrate attenuates blood pressure and sodium retention in DOCA-salt hypertension

Regulation of blood pressure, natriuresis and renal thiazide/amiloride sensitivity in PPARalpha null mice

Macrophage-specific PPARgamma controls alternative activation and improves insulin resistance

Down-regulation of catalase and oxidative modification of protein kinase CK2 lead to the failure of apoptosis repressor with caspase recruitment domain to inhibit cardiomyocyte hypertrophy

Apocynin attenuates tubular apoptosis and tubulointerstitial fibrosis in transgenic mice independent of hypertension

p38 Mitogen-activated protein kinase inhibition ameliorates angiotensin II-induced target organ damage

Essential role of AT1A receptor in the development of 2K1C hypertension

Pivotal role of angiotensin II receptor subtype 1A in the development of two-kidney, one-clip hypertension: Study in angiotensin II receptor subtype 1A knockout mice

Simvastatin reverses cardiac hypertrophy caused by disruption of the bradykinin 2 receptor

Effect of ACE inhibitor on DOCA-salt-and aortic coarctation-induced hypertension in mice: Do kinin B2 receptors play a role?

Renovascular hypertension in bradykinin B2-receptor knockout mice

Evaluation of aortic remodeling in apolipoprotein E-deficient mice and renovascular hypertensive mice

Endogenous angiotensin II enhances atherogenesis in apoprotein E-deficient mice with renovascular hypertension through activation of vascular smooth muscle cells

Severe hyperlipidemia causes impaired reninangiotensin system function in apolipoprotein E deficient mice

Enhanced ABCG1 expression increases atherosclerosis in LDLr-KO mice on a western diet

Ablation of the bach1 gene leads to the suppression of atherosclerosis in bach1 and apolipoprotein E double knockout mice

Reduced acute vascular injury and atherosclerosis in hyperlipidemic mice transgenic for lysozyme

Reduced myocardial ischemia-reperfusion injury in tolllike receptor 4-deficient mice

Toll-like receptor-4 modulates survival by induction of left ventricular remodeling after myocardial infarction in mice

Toll-like receptor-2 modulates ventricular remodeling after myocardial infarction

Central role of endogenous toll-like receptor-2 activation in regulating inflammation, reactive oxygen species production, and subsequent neointimal formation after vascular injury

Cholesterol-dependent lipid assemblies regulate the activity of the ecto-nucleotidase CD39

Endothelial-specific expression of caveolin-1 impairs microvascular permeability and angiogenesis

Pharmacogenomics of anesthetic drugs in transgenic LQT1 and LQT2 rabbits reveal genotype-specific differential effects on cardiac repolarization

Mechanisms of cardiac arrhythmias and sudden death in transgenic rabbits with long QT syndrome

Electrical remodeling and arrhythmias in long-QT syndrome: Lessons from genetic models in mice

Mouse models of human arrhythmia syndromes

Caught in the act: In vivo molecular imaging of the transcription factor NF-kappaB after myocardial infarction

Absence of NF-kappaB subunit p50 improves heart failure after myocardial infarction

Tissue-specific effects of the nuclear factor kappaB subunit p50 on myocardial ischemia-reperfusion injury

Endotoxin-induced cardiomyopathy and systemic inflammation in mice is prevented by aldose reductase inhibition

Vascular endothelial cell-specific NF-kappaB suppression attenuates hypertension-induced renal damage

Targeted cardiac overexpression of A20 improves left ventricular performance and reduces compensatory hypertrophy after myocardial infarction

Genome-wide orchestration of cardiac functions by the orphan nuclear receptors ERRalpha and gamma

ERRgamma directs and maintains the transition to oxidative metabolism in the postnatal heart

Troponin T isoforms alter the tolerance of transgenic mouse cardiac muscle to acidosis

Frequency-and afterload-dependent cardiac modulation in vivo by troponin I with constitutively active protein kinase A phosphorylation sites

Troponin I phosphorylation plays an important role in the relaxant effect of beta-adrenergic stimulation in mouse hearts

The antihypertensive chromogranin A-derived peptide catestatin as a novel endocrine/paracrine modulator of cardiac function: Inotropic and lusitropic actions on the rat heart

Catestatin is a novel endogenous peptide that regulates cardiac function and blood pressure

Modulation of angiotensin II-mediated hypertension and cardiac remodeling by lectin-like oxidized low-density lipoprotein receptor-1 deletion

Role of 5-lipoxygenase in myocardial ischemiareperfusion injury in mice

Age-dependent biochemical and contractile properties in atrium of transgenic mice overexpressing junctin

Overexpression of junctin causes adaptive changes in cardiac myocyte Ca(2+) signaling

Structural alterations in cardiac calcium release units resulting from overexpression of junctin

Triadin is a critical determinant of cellular Ca cycling and contractility in the heart

Conduction disturbances and increased atrial vulnerability in Connexin40-deficient mice analyzed by transesophageal stimulation

Electrophysiological characterization of connexin 40 deficient hearts -In vivo studies in mice

Connexin 30.3 is expressed in the kidney but not regulated by dietary salt or high blood pressure

Connexin45 is expressed in the juxtaglomerular apparatus and is involved in the regulation of renin secretion and blood pressure

Increased expression of cyclooxygenase 2 contributes to aberrant renin production in connexin 40-deficient kidneys

Connexin40 regulates renin production and blood pressure

Replacement of connexin43 by connexin26 in transgenic mice leads to dysfunctional reproductive organs and slowed ventricular conduction in the heart

Arrhythmia induced by spatiotemporal overexpression of calreticulin in the heart

Phospholamban overexpression in transgenic rabbits

Effects on recovery during acidosis in cardiac myocytes overexpressing CaMKII

Myocardial fas ligand expression increases susceptibility to AZT-induced cardiomyopathy

Protection against lipopolysaccharide-induced myocardial dysfunction in mice by cardiac-specific expression of soluble fas

Monocyte-specific bcl-2 expression attenuates inflammation and heart failure in monocyte chemoattractant protein-1 (MCP-1)-induced cardiomyopathy

Targeted cardiac expression of soluble fas prevents the development of heart failure in mice with cardiacspecific expression of MCP-1

Protease activated receptors in cardiovascular function and disease

Impaired hemostasis and protection against thrombosis in protease-activated receptor 4-deficient mice is due to lack of thrombin signaling in platelets

Blood pressures, heart rate and locomotor activity during salt loading and angiotensin II infusion in protease-activated receptor 2 (PAR2) knockout mice

Essential role of platelet activation via protease activated receptor 4 in tissue factor-initiated inflammation

New insights into the natriuretic peptide system

Transgenic expression of matrix metalloproteinase-1 inhibits myocardial fibrosis and prevents the transition to heart failure in a pressure overload mouse model

Matrix metalloproteinase 12 accelerates the initiation of atherosclerosis and stimulates the progression of fatty streaks to fibrous plaques in transgenic rabbits

Abnormal vessel formation in the choroid of mice lacking tissue inhibitor of metalloprotease-3

Increased ADAM17 mRNA expression and activity is associated with atherosclerosis resistance in LDL-receptor deficient mice

Role of menkes ATPase in angiotensin II-induced hypertension. A key modulator for extracellular superoxide dismutase function

A beneficial role of cardiac P2X4 receptors in heart failure: Rescue of the calsequestrin overexpression model of cardiomyopathy

Effect of AT2 blockade on cardiac hypertrophy as induced by high dietary salt in the proatrial natriuretic peptide (ANP) gene-disrupted mouse

Reduced vascular remodeling, endothelial dysfunction, and oxidative stress in resistance arteries of angiotensin II-infused macrophage colony-stimulating factor-deficient mice: Evidence for a role in inflammation in angiotensin-induced vascular injury

M-CSF accelerates neointimal formation in the early phase after vascular injury in mice: The critical role of the SDF-1-CXCR4 system

Endothelium-restricted overexpression of human endothelin-1 causes vascular remodeling and endothelial dysfunction

Loss of the aryl hydrocarbon receptor induces hypoxemia, endothelin-1, and systemic hypertension at modest altitude

Mouse models of genetic diseases resulting from mutations in elastic fiber proteins

Developmental adaptation of the mouse cardiovascular system to elastin haploinsufficiency

Functional rescue of elastin insufficiency in mice by the human elastin gene: Implications for mouse models of human disease

Alpha2-antiplasmin is a critical regulator of angiotensin II-mediated vascular remodeling

The CREB leucine zipper regulates CREB phosphorylation, cardiomyopathy, and lethality in a transgenic model of heart failure

CD36 expression contributes to age-induced cardiomyopathy in mice

Factor XIII deficiency causes cardiac rupture, impairs wound healing, and aggravates cardiac remodeling in mice with myocardial infarction

Impaired heart contractility in apelin gene-deficient mice associated with aging and pressure overload

TBX5 transcription factor regulates cell proliferation during cardiogenesis

Enhancing cardiovascular dynamics by inhibition of thrombospondin-1/CD47 signaling

A novel transgenic mice model for venous malformation

Pronounced thrombocytosis in transgenic mice expressing reduced levels of mpl in platelets and terminally differentiated megakaryocytes

Early vascular and neuronal changes in a VEGF transgenic mouse model of retinal neovascularization

Osteopontin transgenic mice fed a high-cholesterol diet develop early fatty-streak lesions

Reverse cholesterol transport and cholesterol efflux in atherosclerosis

Neurogenic mechanisms contribute to hypertension in mice with disruption of the K-cl cotransporter KCC3

Cardiac specific increase in aldosterone production induces coronary dysfunction in aldosterone synthase-transgenic mice

Targeted disruption of the mouse Csrp2 gene encoding the cysteine-and glycine-rich LIM domain protein CRP2 result in subtle alteration of cardiac ultrastructure

Intravenous delivery of PTH/PTHrP type 1 receptor cDNA to rats decreases heart rate, blood pressure, renal tone, renin angiotensin system, and stress-induced cardiovascular responses

Vitamin D and human health: Lessons from vitamin D receptor null mice

A role for the thromboxane (tp) receptor in l -NAME hypertension

Role of the T cell in the genesis of angiotensin II induced hypertension and vascular dysfunction

Deletion of transient receptor potential vanilloid type 1 receptors exaggerates renal damage in deoxycorticosterone acetate-salt hypertension

Lack of the serotonin transporter does not prevent mineralocorticoid hypertension in rat and mouse

Role of inflammation in the development of renal damage and dysfunction in angiotensin II-induced hypertension

Thymosin beta4 is an essential paracrine factor of embryonic endothelial progenitor cell-mediated cardioprotection