Published September 4, 2024, 05:58
Medicine: An important discovery for the treatment of diabetes
According to the University of Geneva, we could force the cells of the pancreas to secrete insulin to balance our sugar levels.
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Diabetes is characterized by a high blood sugar level, often detected when the disease is already well advanced.
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To keep our blood sugar levels at an adequate level, everything relies on the ability of the beta cells of the pancreas to detect glucose and secrete insulin. If these cells malfunction, the balance is upset and diabetes appears.
Until now, the scientific community agreed that beta cells needed the other hormone-producing cells present in the pancreas to function properly. A team from the University of Geneva (UNIGE) has demonstrated the opposite: in adult mice whose pancreas only has beta cells, blood sugar regulation and insulin sensitivity are even better than in standard animals, we can read in the journal «Nature Metabolism».
Cells that change function
In 2010, the team of Pedro Herrera, professor at the Department of Genetic Medicine and Development and at the Diabetes Center of the Faculty of Medicine of UNIGE, discovered this astonishing capacity of pancreatic cells to change function. In the event of premature death of beta cells, endocrine cells usually responsible for producing other hormones, such as glucagon or somatostatin, can start producing insulin.
“Until now, it was thought that the differentiated adult cells of an organism could not regenerate and reorient themselves functionally. Triggering this cellular plasticity pharmacologically could thus be the basis of an entirely new therapy against diabetes. But what happens if all the cells of the endocrine pancreas abandon their initial function to produce insulin? This is what we wanted to know in our new study,” explains Pedro Herrera.
Better with only beta cells
It was commonly accepted that beta cells could only function properly in the presence of other hormone-producing cells, alpha, delta and gamma cells, grouped together in islets in the pancreas. “To test this, we used mice in which, once they reached adulthood, it is possible to selectively eliminate all non-beta cells from the pancreas in order to observe how beta cells manage to regulate blood sugar,” explains Marta Perez Frances, a researcher in Pedro Herrera’s laboratory and first author of this work. “But, surprisingly, not only were our mice perfectly capable of managing their blood sugar effectively, but they were even healthier than the mice in the control group!”
Even when fed a high-fat diet or tested for insulin resistance, one of the main markers of diabetes, these mice showed better insulin sensitivity in all target tissues, including adipose tissue. Why? “There is an adaptation process in which the body recruits other hormonal cells outside the pancreas to cope with the sudden decrease in glucagon and other pancreatic hormones,” notes Pedro Herrera.
“But this clearly shows that non-beta cells in the islets of the pancreas are not essential for maintaining glycemic balance.” These results are surprising and go against the conception that has prevailed until now.
New therapies are emerging
Naturally, about 2% of pancreatic cells change jobs when insulin is deficient. The challenge is to identify a molecule that can force and amplify this conversion. Another strategy is to differentiate stem cells in vitro to produce new beta cells before transplanting them into diabetic people.
“Our results provide evidence that strategies focusing on insulin cells could really pay off,” says Pedro Herrera. “The next step in our work will therefore be to establish the molecular and epigenetic profile of non-beta cells from diabetic and non-diabetic people, in the hope of identifying elements that could induce the conversion of these cells in the pathological context of diabetes.”
