After years of type 2 diabetes, red blood cells may quietly turn against the heart—offering a new clue for spotting danger early.
People who live with type 2 diabetes for many years face a steadily increasing risk of cardiovascular disease. New research from Karolinska Institutet, published in the journal Diabetes, suggests that changes inside red blood cells may help explain why this risk grows over time. The study also highlights a specific molecule that could serve as an early warning signal for future heart problems.
How Diabetes Affects Blood Vessels Over Time
Type 2 diabetes is already known to raise the chances of heart attacks and strokes, and that danger rises the longer the condition lasts. Earlier studies have shown that red blood cells can influence how blood vessels function in people with diabetes. This new research adds an important detail by showing that the length of time a person has diabetes strongly affects when these blood cell changes appear and how severe they become. After many years, red blood cells may begin to actively damage blood vessels rather than simply reflect existing disease.
Evidence From Patients and Animal Studies
The research team examined both animal models and people with type 2 diabetes. They found that red blood cells taken from mice and from patients with long-standing diabetes interfered with normal blood vessel function. In contrast, red blood cells from newly diagnosed patients did not cause this problem. However, after seven years of follow-up, those same patients showed similar harmful changes in their blood cells. When scientists restored levels of microRNA-210 in the red blood cells, blood vessel function improved.
“What really stands out in our study is that it is not only the presence of type 2 diabetes that matters, but how long you have had the disease. It is only after several years that red blood cells develop a harmful effect on blood vessels,” says Zhichao Zhou, associate professor at the Department of Medicine, Solna, Karolinska Institutet, and lead author of the study.
A Potential Biomarker for Early Risk Detection
The findings point to microRNA-210 in red blood cells as a possible biomarker that could help identify patients at higher risk for cardiovascular complications. Researchers are now exploring whether this marker can be reliably used in larger population studies.
“If we can identify which patients are at greatest risk before vascular damage has already occurred, we can also become better at preventing complications,” says Eftychia Kontidou, doctoral student from the same group and the first author of the study.
Reference: “Long Duration of Type 2 Diabetes Drives Erythrocyte-Induced Vascular Endothelial Dysfunction: A Link to microRNA-210-3p” by Eftychia Kontidou, Aida Collado, Rawan Humoud, Kesavan Manickam, John Tengbom, Tong Jiao, Michael Alvarsson, Jiangning Yang, Linda Mellbin, Ali Mahdi, John Pernow and Zhichao Zhou, 9 January 2026, Diabetes.
DOI: 10.2337/db25-0463
The study is funded by, among others, the EFSD/Novo Nordisk Foundation Future Leaders Award, the Swedish Heart-Lung Foundation, and the Swedish Research Council. The researchers report no conflicts of interest.
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