Diabetes-like symptoms in COVID-19.
The coronavirus SARS-CoV-2 can affect many organs, especially the lungs, respiratory tract, digestive tract, cardiovascular system as well as the nervous system. A German research team has now demonstrated that the metabolism can also be affected by COVID-19. The reason for this is that SARS-CoV-2 can infect the insulin-producing beta cells of the pancreas.
In a recent study, researchers at the University of Ulm show that SARS-CoV-2 is able to infect the pancreas. They say this may explain diabetes-like disease symptoms in severe COVID-19 courses, as well as the deterioration in sugar metabolism that some affected individuals experience after infection. The research findings were presented in the prestigious journal Nature Metabolism.
Impaired blood glucose levels in COVID-19 sufferers.
“In patients with COVID-19 disease, there are always courses in which the regulation of blood glucose levels is also disturbed,” explains senior physician Professor Martin Wagner from the research team. Typically, such complaints occur in patients suffering from type 1 diabetes.
Consequences of a pancreas infection
As the physicians report, the symptoms range from hyperglycemia, a serious form of hyperglycemia, to ketoacidosis, i.e. hyperacidity of the blood. “In this regard, current studies report exacerbations of known diabetes mellitus diseases, but also cases of new-onset diabetes after having undergone COVID-19,” adds Professor Alexander Kleger.
What was studied?
In a joint project of Internal Medicine 1, the Institute of Molecular Virology and the Institute of Pathology, the research group investigated how these diabetes-like symptoms can occur in COVID-19 sufferers. For this purpose, the scientists brought tissue from the pancreas into contact with SARS-CoV-2.
SARS-CoV-2 attacks pancreatic beta cells
The team discovered that the coronavirus can also attack the so-called islets of Langerhans in the pancreas. These are hormone-producing structures that contain, among other things, beta cells in which the production of insulin takes place. “These beta cells express certain protein molecules, without which SARS-CoV-2 cannot infect the cells,” explains virologist Professor Jan Münch. The protein molecules produced there include the proteins TMPRSS2 and ACE2, via which SARS-CoV-2 can enter the cells.
Metabolic disorders due to infection of the pancreas
“As a result, the viral building blocks multiply, and many new infectious viral particles are released – which is exactly what we observed in Langerhans’ islets,” Münch said. In addition, the team found that infected insulin-producing tissue undergoes crucial changes in form and function. According to Professor Münch, infection of the pancreas led to a reduced number of insulin granules, where beta cells store insulin. “No wonder, then, that in these cases the secretion of this vital hormone that regulates blood sugar levels was disturbed,” add Dr. Janis Müller and Dr. Sandra Heller from the research group.
Autopsies confirmed the findings
As the study progressed, the researchers were able to clearly demonstrate SARS-CoV-2 involvement of the pancreas in autopsies of deceased COVID-19 sufferers. “The amazing thing about this is that even after no more viral proteins were found in the lungs, they could still be detected in the pancreas, and this was the case with disease courses of varying lengths,” emphasizes pathologist Professor Thomas Barth.
Inflammation of the pancreas
According to the researchers, the pancreas not only produces the hormone insulin, but the organ also releases digestive juices in the duodenum that break down fats, carbohydrates and proteins from food. As the team found, the digestive enzyme-producing pancreatic tissue was also infected with SARS-CoV-2.
The significance of this for the clinical course of COVID-19 is currently unclear. Professor Kleger, who heads the pancreas outpatient clinic at the University Hospital of Ulm, emphasizes that inflammation of the pancreas has already been observed in the context of COVID-19.
Can COVID-19 cause diabetes?
One of the most important questions in this context is whether the acutely occurring impairments in insulin production in COVID-19 sufferers can lead to diabetes in the long term. According to the research team, further studies are needed to clarify this issue.