Indirect and Direct Effects of SARS-CoV-2 on Human Pancreatic Islets

Area of Science:

• Endocrinology
• Virology
• Immunology

Background:

• Emerging evidence links SARS-CoV-2 infection to metabolic complications, including hyperglycemia.
• COVID-19 patients exhibit altered glucose metabolism, suggesting pancreatic islet dysfunction.

Purpose of the Study:

• To investigate the direct and indirect effects of SARS-CoV-2 on human pancreatic islets in hyperglycemic COVID-19 patients.
• To elucidate the mechanisms underlying COVID-19-associated hyperglycemia.

Main Methods:

• Analysis of serum from 10 hyperglycemic COVID-19 patients for islet toxicity.
• Assessment of cytokine receptor expression on human pancreatic islets.
• Detection of unmethylated INS DNA as a marker of cell death.
• Postmortem pancreatic tissue pathology in deceased COVID-19 patients.

Main Results:

• Patient serum showed toxicity to human islets, reduced by anti-cytokine therapies (anti-IL-1β, anti-IL-6, anti-TNFα).
• Pancreatic islets express receptors for these upregulated cytokines.
• Increased unmethylated INS DNA indicated beta-cell death.
• Postmortem analysis revealed SARS-CoV-2 RNA, altered insulin processing, and beta-cell damage in hyperglycemic COVID-19 patients.

Conclusions:

• SARS-CoV-2 negatively impacts human pancreatic islet function and survival through inflammatory pathways and potential direct viral tropism.
• These effects contribute to the metabolic abnormalities, specifically hyperglycemia, observed in COVID-19 patients.