key: cord-0933462-xc35lk9t
authors: Fondevila, Marcos F.; Mercado-Gómez, Maria; Rodríguez, Amaia; Gonzalez-Rellan, Maria J.; Iruzubieta, Paula; Valentí, Víctor; Escalada, Javier; Schwaninger, Markus; Prevot, Vincent; Dieguez, Carlos; Crespo, Javier; Frühbeck, Gema; Martinez- Chantar, Maria L.; Nogueiras, Ruben
title: Obese patients with NASH have increased hepatic expression of SARS-CoV-2 critical entry points
date: 2020-10-20
journal: J Hepatol
DOI: 10.1016/j.jhep.2020.09.027
sha: e74de590a2ff5df3a27b9a2e84bb652fc415fbf9
doc_id: 933462
cord_uid: xc35lk9t

nan

We read with great interest the article published by Biquard and colleagues showing that, according to public transcriptomic data, the hepatic expression of angiotensin converting enzyme 2 (ACE2) and the cellular transmembrane protease serine 2 (TMPRSS2) remains unchanged in patients with metabolic-associated fatty liver disease (MAFLD) [1] . SARS-CoV-2 attaches to cells via binding to its receptor ACE2 and, TMPRSS2 cleaves the SARS-CoV-2 spike protein, allowing fusion of cellular and viral membranes [2] . Despite this retrospective study, there is growing evidence that patients with MAFLD have a higher risk of COVID-19 disease progression [3] [4] [5] .

Given the ongoing discussion, we have assessed the expression of SARS-CoV-2 cell entry molecules in the liver of obese patients with NAFLD and/or T2D (See Supplementary table 1 for detailed characteristics) , since this information seems crucial to understand and prevent cell infection. Taking into consideration that T2D has been associated with a worse prognosis in patients with COVID-19 and well-controlled glycemia was associated with a markedly improved outcome in these patients and the pre-existing T2D [6] , we first focused on patients with T2D. Liver mRNA expression of ACE2 was significantly lower in T2D patients while TMPRSS2 also tended to decrease but was not statistically significant ( Figure 1A ). Then, we analysed separately men and women. In men, hepatic ACE2 and TMPRSS2 expression remained unchanged between the two groups ( Figure 1B ). However, in women with T2D, ACE2 was significantly lower while TMPRSS2 gene expression tended to decrease compared to women without T2D ( Figure 1B) . These results indicate that while the machinery of cellular entrance of SARS-CoV-2 does not suffer major alterations in the liver of obese men with T2D, its downregulation in women might indicate a lower susceptibility to liver injury. These J o u r n a l P r e -p r o o f findings are in consonance with the well-established protective role of estrogens in dysmetabolism [7] .

Next, we measured the expression of these genes in the liver according to the presence of NAFLD. Liver mRNA expression of both ACE2 and TMPRSS2 did not show differences between subjects without liver injury and patients with only steatosis, but these genes were upregulated in obese patients with NASH ( Figure 1C ). Moreover, ACE2 and TMPRSS2, were positively correlated with NAS score ( Figure 1D ). Of note, TMPRSS2 was also positively correlated with weight, BMI and cholesterol (data not shown). These results are apparently different to the ones described in a previous study performing transcriptomics in individuals without and with MAFLD [1, 8] and also animal models of diet-induced NASH [8] , where no changes were detected for either ACE2 or TMPRSS2. However, it is important to highlight that there are important differences in the characteristics of the cohorts. In contrast to the previous report that analyzed lean and obese patients with MAFLD or NASH [1] , our cohort is exclusively composed of obese patients. Moreover, whereas in the previous analysis T2D is not mentioned, in our cohort a significant percentage of patients had T2D, which commonly coexists with MAFLD [9] . Lastly, methodological differences might also explain the discrepant results, since we used real-time PCR to specifically measure gene expression of ACE2 and TMPRSS2, while in the previous reports [8] results were obtained by less quantitative techniques namely microarray or RNAseq. Further studies using larger cohorts of patients with liver damage need to be meticulously evaluated to understand whether the SARS-CoV-2 receptor ACE2 and the serine protease TMPRSS2 are indeed affected in advanced stages of NAFLD and to which extent their expression affects the incidence of complications, severity and mortality. 

No evidence for an increased liver uptake of SARS-CoV-2 in metabolic-associated fatty liver disease

SARS-CoV-2 Cell Entry Depends on ACE2 and TMPRSS2 and Is Blocked by a Clinically Proven Protease Inhibitor

Non-alcoholic fatty liver diseases in patients with COVID-19: A retrospective study

Younger patients with MAFLD are at increased risk of severe COVID-19 illness: A multicenter preliminary analysis

Metabolicassociated fatty liver disease is associated with severity of COVID-19

Association of Blood Glucose Control and Outcomes in Patients with COVID-19 and Pre-existing Type 2 Diabetes

The role of estrogens in control of energy balance and glucose homeostasis

DNA methylation analysis in nonalcoholic fatty liver disease suggests distinct diseasespecific and remodeling signatures after bariatric surgery

NAFLD: a multisystem disease