1. Colonic Epithelial Angiotensin-Converting Enzyme 2 (ACE2) Expression in Blacks and Whites: Potential Implications for Pathogenesis Covid-19 Racial Disparities
- Author
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De La Cruz, Mart, Nunes, David P., Bhardwaj, Vaishali, Subramanyan, Deepika, Zaworski, Caroline, Roy, Priya, and Roy, Hemant K.
- Abstract
Background: Covid-19 toll is disproportionate in Blacks although the mechanisms remain incompletely understood. From a biological perspective, several host proteins have received most attention as logical susceptibility targets. Specifically, angiotensin-converting enzyme 2 (ACE2) serves as the epithelial cell receptor and acts in concert with transmembrane protease serine 2 (TMPRSS2). Intriguingly, ACE2 can also suppress the inflammatory response and therefore may impact the severity of Covid-19 infections (from the exuberant immune response a.k.a. “cytokine storm”). We, therefore, assessed expression of ACE2 and TMPRSS2 in Blacks versus Whites. Methods: Archived mucosal biopsies from colonoscopic biopsies of visually normal rectal mucosa without concurrent neoplasia or inflammation were used for this study. Total mRNA was isolated and subjected to real-time polymerase chain reaction for ACE2, and TMPRSS2 was assessed from non-Hispanic Blacks (n= 45) and non-Hispanic Whites (n= 38). GAPDH and beta-actin were used for normalization. Multivariable analysis was performed using Analyse-IT software. Results: ACE2 and TMPRSS2 levels were not altered by gender, BMI, or age. ACE2 levels were lower in Blacks than Whites achieving statistical significance in multivariable (0.51-fold, p= 0.03) but not quite in univariable (p= 0.07) analysis. This downregulation was mirrored in TMRPSS2 in both univariable (p= 0.03) and multivariable analyses (0.41-fold, p= 0.02). Moreover, there was a strong correlation between ACE2 and TMPRSS2 levels (r-squared = 0.78). Conclusions: To our knowledge, this is the first report on racial differences inACE2 and TMPRSS2 mucosal expression. This may provide potential biological underpinnings for the disproportionately higher mortality of Covid-19 in Blacks and should spur future studies.
- Published
- 2022
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