Diabetes is associated with increased mortality from Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2).
Given literature suggesting a potential association between SARS-CoV-2 infection and diabetes induction, it was examined pancreatic expression of angiotensin-converting enzyme-2 (ACE2), the key entry factor for SARS-CoV-2 infection.
Specifically, in this paper published on Cell Metabolism, were analyzed five public scRNA-seq pancreas datasets and performed fluorescence in situ hybridization, Western blotting and immunolocalization for ACE2 with extensive reagent validation on normal human pancreatic tissues across the lifespan, as well as those from coronavirus disease 2019 (COVID-19) cases.
These in silico and ex vivo analyses demonstrated prominent expression of ACE2 in pancreatic ductal epithelium and microvasculature, but we found rare endocrine cell expression at the mRNA-level.
Pancreata from individuals with COVID-19 demonstrated multiple thrombotic lesions with SARS-CoV-2 nucleocapsid protein expression that was primarily limited to ducts.
These results suggest SARS-CoV-2 infection of pancreatic endocrine cells, via ACE2, is an unlikely central pathogenic feature of COVID-19-related diabetes.
The same observations have been published in another paper on Cell Metabolism entitled: SARS-CoV-2 Cell Entry Factors ACE2 and TMPRSS2 are Expressed in the Microvasculature and Ducts of Human Pancreas but are Not Enriched in β Cells.
In this paper were analyzed six transcriptional datasets of primary human islet cells and found that ACE2 and TMPRSS2 were not co-expressed in single β cells.
In pancreatic sections, ACE2 and TMPRSS2 protein was not detected in β cells from donors with and without diabetes. Instead, ACE2 protein was expressed in islet and exocrine tissue microvasculature and in a subset of pancreatic ducts, whereas TMPRSS2 protein was restricted to ductal cells. These findings reduce the likelihood that SARS-CoV-2 directly infects β cells in vivo through ACE2 and TMPRSS2.