key: cord-0852223-dlycz6vv authors: Gu, Jie‐Chao; Wu, Yue‐Guan; Huang, Wei‐Gang; Fan, Xiu‐Jing; Chen, Xin‐Hao; Zhou, Biao; Lin, Zhi‐Jun; Feng, Xiu‐Lan title: Effect of vitamin D on oxidative stress and serum inflammatory factors in the patients with type 2 diabetes date: 2022-04-11 journal: J Clin Lab Anal DOI: 10.1002/jcla.24430 sha: 655f395d599244566f0b33d2743424354da4b8d9 doc_id: 852223 cord_uid: dlycz6vv The type 2 diabetes mellitus (T2DM) is an urgent global health problem. T2DM patients are in a state of high oxidative stress and inflammation. Vitamin D and glutathione (GSH) play crucial roles in antioxidation and anti‐inflammation. However, T2DM patients have lower vitamin D and GSH levels than healthy persons. A randomized controlled trial was conducted to see the effect of the vitamin D supplementation on oxidative stress and inflammatory factors in T2DM patients. In this study, a total of 178 T2DM patients were randomly enrolled, 92 patients received regular treatment (T2DM group) and 86 patients in Vitamin D group received extra vitamin D 400 IU per day in addition to regular treatment. Serum vitamin D, GSH, GSH metabolic enzyme GCLC and GR, inflammatory factor MCP‐1, and IL‐8 levels were investigated. We found that the T2DM group has significantly higher concentrations of MCP‐1 and IL‐8 than those in the healthy donor group. After vitamin D supplementation for 90 days, T2DM patients had a 2‐fold increase of GSH levels, from 2.72 ± 0.84 to 5.76 ± 3.19 μmol/ml, the concentration of MCP‐1 decreased from 51.11 ± 20.86 to 25.42 ± 13.06 pg/ml, and IL‐8 also decreased from 38.21 ± 21.76 to 16.05 ± 8.99 pg/ml. In conclusion, our study demonstrated that vitamin D could regulate the production of GSH, thereby reducing the serum levels of MCP‐1 and IL‐8, alleviating oxidative stress and inflammation, providing evidence of the necessity and feasibility of adjuvant vitamin D treatment among patients with T2DM. On the other hand, vitamin D and GSH levels have important diagnostic and prognostic values in T2DM patients. The type 2 diabetes mellitus (T2DM) is an urgent global health problem. It is suggested that hyperglycemia increases oxidative stress; however, the antioxidant function in diabetic patients is diminished, resulting in the augment of oxidative stress. 3, 4 High concentrations of glucose induce the secretion of inflammatory cytokine MCP-1 and leukocyte interleukin-8 (IL-8) by activating the reactive oxygen species (ROS) and NF-κB pathways. 5, 6 High serum levels of MCP-1 and IL-8 accelerate the progression of diabetes and increase the incidence of complications. [7] [8] [9] As a result, therapeutic agents against ROS have also been widely studied in the treatments of diabetes mellitus. 10 There is convincing evidence of the benefit of vitamin D on antioxidation. [11] [12] [13] Vitamin D is a fat-soluble vitamin responsible for building and maintaining bones by regulating calcium homeostasis. 14 The active hormone derived from vitamin D is 1,25(OH) 2 D3, which mediates numerous biological processes. The active vitamin D is associated with many other cellular functions like anti-inflammatory and antioxidant properties to support physiological function and activity. [15] [16] [17] It can be used to treat rickets, osteoporosis, hypothyroidism, psoriasis, and diseases caused by a lack of calcium or vitamin D. Vitamin D has also been reported to prevent the development of cancers. The deficiency of active vitamin D is related to the incidence of complications in T2DM patients. 18 Vitamin D possesses high antioxidant and anti-inflammatory properties by increasing the formation of glutathione (GSH). 19 ,20 GSH helps to reduce the reactive oxygen level in the blood. 21 Meanwhile, long-lasting hyperglycemia results in a low level of GSH. 22 In addition, GSH deficiency leads to the progression of diabetes and the development of complications. 23, 24 Vitamin D is critical for maintaining homeostasis in T2DM patients. However, the effects of vitamin D in the treatment of T2DM in Southern Chinese people remain to be further investigated. This study focuses on the effect of the supplementation of vitamin D on oxidative stress and inflammatory factors in patients with type 2 diabetes in a southern city of China. We conducted a randomized This study is a randomized controlled trial (RCT) and was approved by the Committee of Ethics and Research of the People's Hospital of Jiangmen (Approval No.:20200220-8). We have followed the CONSORT guideline 25 to perform the research. A total of 200 adult patients diagnosed with type 2 diabetes were included and divided into two groups randomly. Patients with the following criteria were excluded: a history of cardiovascular disease, chronic liver or kidney disorders, endocrinology disorders, insulin treatment, cancer, and women in pregnancy or lactation. After Then, after adding the substrate of the enzyme, the substrate was catalyzed by the enzyme into colored products. The amount of the indicated molecules was positively linearly related to the amount of the colored products, so the concentrations of the tested molecules could be calculated. The plasma concentrations of GR were tested using the U.V. spectrophotometric method (Zhongtuo biomedical Co., Ltd #ZF2110F). GR catalyzes the reduction of GSSG to GSH using NADPH, measuring the decrease in the rate of NADPH absorption peak at 340nm to calculate the activity of GR. All appropriate tests, controls, and standards were measured according to the manufacturer's instructions. The results are expressed as mean ± standard error. The statistical difference between groups was analyzed using Student's t-test. Pearson's correlation analysis was performed to determine the relationships between variables. The results were considered significant at p < 0.05. The statistical calculations were done using GraphPad Prism 8.0. On the other hand, we also tested the serum vitamin D levels of patients with T2DM and healthy donors. It is shown that serum vitamin D levels of T2DM patients (20.04 ± 6.85 ng/ml) are significantly lower than that of healthy donors (32.71 ± 13.83 ng/ml; Figure 1C ). These results suggested that T2DM patients generally lack vitamin D and are in a high oxidative and inflammatory condition. We also found that the concentrations of blood inflammatory markers are significantly negatively correlated with the vitamin D levels ( Figure 1D-G) , irrespective of healthy donor group or T2DM group, indicating that vitamin D may reduce the oxidative and inflammatory levels, which are consistent with previous studies. 15, 16, 26, 27 In the vitamin D group, after the supplementation of vitamin D for 90 days, the serum vitamin D levels significantly increased and were back to normal levels (36.57654321 ± 12.66437866 vs. 17.21851852 ± 7.950170603 ng/ml; Figure 2A) . These results showed that the supplementation of vitamin D besides regular treatment could recover the deficiency of vitamin D in the blood of these patients. In the meanwhile, the MCP-1 and IL-8 levels were significantly lower in the blood of T2DM patients after adjuvant treatment of vitamin D. MCP-1 levels decreased from 51.11 ± 20.86 pg/ml to 25.42 ± 13.06 pg/ml, and the concentrations of IL-8 also reduced from 38.21 ± 21.76 to 16.05 ± 8.99 pg/ml ( Figure 2B, C) . The result showed that active vitamin D3 could effectively lower the oxidative stress in T2DM patients. With the evidence that vitamin D participates in the metabolism of GSH, 28 On the other hand, we found that the concentrations of MCP-1 and IL-8 are also significantly negatively correlated with the GSH levels ( Figure 5A, B) , irrespective of healthy donor group or T2DM group, indicating that GSH is upregulated by vitamin D and thereby alleviates the oxidative stress and inflammatory conditions. In conclusion, the results above indicate that the supplemen- Under the induction of obesity, unhealthy lifestyle, aging, and other risk factors, the diabetic-susceptible population will develop pancreatic β-cell dysfunction and insulin resistance, leading to hyperglycemia. Oxidative stress is involved in the occurrence and development of T2DM and its complications; therefore, related research on the prevention and control of T2DM is urgent. Previous studies have shown that the high glucose and free fatty acids level in plasma increases oxidative stress by enhancing the production of free radicals. 30 High glucose levels in the blood could boost the production of oxidative radicals, leading to insulin resistance, impaired insulin secretion, and diabetic vascular lesions, 31 44 GSH participates in many physiological and pathological processes, such as detoxification, regulates cell viability, and participates in the progression of chronic diseases like cardiovascular diseases, immune diseases, and diabetes. 23 Biosynthesis of GSH is tightly regulated by GCL activity, the catalytic component of which is GCLC. GR is responsible for maintaining the reduced form of GSH, which is responsible for eliminating radical oxidants. properties. It can effectively modulate the levels of GSH by affecting the activity and the expression levels of critical enzymes like GSH peroxidase superoxide dismutase (GPx1) and GR in GSH metabolism. 19 It is reported that the supplementation of vitamin D could significantly reduce the incidence of gestational diabetes and decrease the prevalence of kidney or cardiovascular complications in T2DM patients. 45 Some studies indicated that supplementation with vitamin D could modulate the inflammation symptoms and improve the defense against some chronic infections. 26, 27, 46 However, the prevalence of vitamin D deficiency is surprisingly high and widespread among all ages and worldwide, and it may be associated with several chronic diseases, 47, 48 including type 2 diabetes. Studies on the relationship between hyperglycemia, oxidative stress, and GSH implied that reductive glutathione could lower the oxidative stress, helping to control the circular glucose level and its complications. 49 Oxidative stress and diabetes, these two processes are likely to reinforce each other. However, the relationships between GSH, oxidative stress, and inflammatory cytokines remain to be investigated in T2DM patients. This study is a single-center study with several potential limitations, our study only includes patients in our hospital, and continuous measurements need to be further investigated. At the same time, racial and ethnic differences and biorhythm differences exist. But our study demonstrated the ability of vitamin D to improve circulating GSH levels and reduce inflammatory factors. These findings could provide evidence of the beneficial effects of vitamin D supplementation in patients with T2DM. In addition, the regular inspection of vitamin D and GSH concentrations in the blood of T2DM patients is a promising way to monitor the progression of this disease. Not applicable. The authors declare that they have no competing interests. Not applicable. All data generated or analyzed during this study are included in this article. Xiu-Lan Feng https://orcid.org/0000-0003-3458-1635 Prevalence and ethnic pattern of diabetes and prediabetes in China in 2013 Global aetiology and epidemiology of type 2 diabetes mellitus and its complications Diabetic Complications and oxidative stress: a 20-year voyage back in time and back to the future Oxidative stress in diabetes mellitus and the role of vitamins with antioxidant actions High glucose stimulates TNFalpha and MCP-1 expression in rat microglia via ROS and NF-kappaB pathways Effects of ROS-relative NF-kappaB signaling on high glucose-induced TLR4 and MCP-1 expression in podocyte injury Chemokines in prediabetes and type 2 diabetes: a meta-analysis Monocyte chemoattractant protein-1 predicts the development of diabetic nephropathy The IL-8-CXCR1/2 axis contributes to diabetic kidney disease Oxidative stress and diabetes: antioxidative strategies The effects of vitamin D supplementation on metabolic and oxidative stress markers in patients with type 2 diabetes: a 6-month follow up randomized controlled study The role of vitamin D deficiency and elevated inflammatory biomarkers as risk factors for the progression of diabetic nephropathy in patients with type 2 diabetes mellitus The effects of vitamin D on Immune system and inflammatory diseases Overview of general physiologic features and functions of vitamin D Effects of vitamin D on inflammatory and oxidative stress responses of human bronchial epithelial cells exposed to particulate matter Vitamin D (VD3) antioxidative and anti-inflammatory activities: Peripheral and central effects Vitamin D receptor agonists' anti-inflammatory properties Diminished 25-OH vitamin D3 levels and vitamin D receptor variants are associated with susceptibility to type 2 diabetes with coronary artery diseases Vitamin D supplementation is associated with increased glutathione peroxidase-1 levels in Arab adults with prediabetes Low serum vitamin D concentration is correlated with anemia, microinflammation, and oxidative stress in patients with peritoneal dialysis The prognostic role of glutathione and its related antioxidant enzymes in the recurrence of hepatocellular carcinoma Hyperglycemia (highglucose) decreases L-cysteine and glutathione levels in cultured monocytes and blood of Zucker diabetic rats The relationship between the level of glutathione, impairment of glucose metabolism and complications of diabetes mellitus Glutathione participation in the prevention of cardiovascular diseases Statement: updated guidelines for reporting parallel group randomised trials Inflammation and vitamin D: the infection connection Vitamin D as an antimicrobial and anti-inflammatory therapy for Cystic Fibrosis Vitamin D upregulates glutamate cysteine ligase and glutathione reductase, and GSH formation, and decreases ROS and MCP-1 and IL-8 secretion in high-glucose exposed U937 monocytes Vitamin D and L-cysteine levels correlate positively with GSH and negatively with insulin resistance levels in the blood of type 2 diabetic patients Oxidative stress and glycemic regulation The etiology of oxidative stress in insulin resistance Oxidative stress, insulin resistance, dyslipidemia and type 2 diabetes mellitus Diabetes mellitus and oxidative stress-A concise review High-glucose stimulation increases reactive oxygen species production through the calcium and mitogenactivated protein kinase-mediated activation of mitochondrial fission High glucose-induced ROS production stimulates proliferation of pancreatic cancer via inactivating the JNK pathway Oxidative stress and diabetic complications The role of inflammation in diabetes: current concepts and future perspectives Reactive oxygen species-mediated signaling pathways in angiotensin II-induced MCP-1 expression of proximal tubular cells Reactive oxygen species mediate IL-8 expression in Down syndrome candidate region-1-overexpressed cells Reactive oxygen species mediate Jak2/Stat3 activation and IL-8 expression in pulmonary epithelial cells stimulated with lipid-associated membrane proteins from Mycoplasma pneumoniae Glutathione as a marker for human disease Glutathione induced immunestimulatory activity by promoting M1-like macrophages polarization via potential ROS scavenging capacity Reactive oxygen species and endothelial function in diabetes ROS and hypoxia signaling regulate periodic metabolic arousal during insect dormancy to coordinate glucose, amino acid, and lipid metabolism Role of vitamin Dcalcium supplementation on metabolic profile and oxidative stress in gestational diabetes mellitus: A randomized controlled trial Evidence that vitamin D supplementation could reduce risk of influenza and COVID-19 infections and deaths Association of Vitamin D status with chronic disease risk factors and cognitive dysfunction in 50(-)70 year old adults Vitamin D and chronic diseases Glutathione synthesis is diminished in patients with uncontrolled diabetes and restored by dietary supplementation with cysteine and glycine Anti-inflammatory agents in the treatment of diabetes and its vascular complications Anti-inflammatory phytochemicals for the treatment of diabetes and its complications: Lessons learned and future promise Diabetic retinopathy: role of inflammation and potential therapies for anti-inflammation