Wrong diet leads to fatal activation of immune cells

16-Mar-2022 - Germany

Overweight and obesity are one of the greatest health challenges of the 21st century, writes the World Health Organization (WHO). Almost 60 percent of Germans are overweight, and 25 percent are obese. Obesity is often the trigger for serious secondary diseases such as diabetes, arteriosclerosis or heart attacks.

Medical experts are concerned about the fatty tissue in the abdominal cavity, the so-called visceral fatty tissue, whose strong increase is associated with an inflammatory response affecting the entire body and thus increases the risk of secondary diseases. The visceral adipose tissue plays a significant role in these processes, as immune cells can arrange themselves here in lymphoid structures and initiate immune responses that derail the metabolism.

DonnaSenzaFiato / Pixabay

After just three weeks of a high-fat, high-calorie diet, the molecular processes in the organism that control the immune system and metabolism change. Susanne Stutte

Nutrition is decisive

A team of researchers at LMU has now investigated the molecular processes that influence this so-called immune metabolism. Nutrition plays a decisive role: "After just three weeks of a high-fat, high-calorie diet, the molecular processes in the organism that control the immune system and metabolism change," explains Dr. Susanne Stutte of the Biomedical Center and lead author of the study. Excess food energy is stored in white adipose tissue, known as visceral fat, and accumulates throughout the body and between internal organs. While everyone has this, it can grow significantly due to a particularly high-calorie or high-fat diet, making it hazardous to health.

With the constant growth of visceral fat, immunological processes also become unbalanced, as the researchers were able to show: Certain immune cells, so-called plasmacytoid dendritic cells (pDCs) now accumulate in the fatty tissue. "A tertiary lymphoid tissue forms here, in which the pDCs now drive the immune system and metabolism in a fatal way," explains Stutte.

Chronic inflammation

The more fat is formed, the more of these structures are created. They acutely interfere with the metabolism, resulting in a metabolic syndrome. This means that the pDCs in visceral fat are on constant alert.

"The pDCs normally represent the first barrier in a viral infection, where they react and release a messenger substance (the type-1 interferon) that regulates the immune system," explains Professor Barbara Walzog from the Walter Brendel Center for Experimental Medicine at LMU and head of the SFB 914 "Trafficking of Immune Cells in Inflammation, Development and Disease." If metabolic syndrome occurs, metabolism derails and inflammation levels rise. "After only three weeks of high-calorie diets, we were able to detect the development of type 2 diabetes, induced by the growing visceral fat," Stutte reports.

Molecular maps

The results were obtained in cooperation with Harvard Medical School and, according to the scientists, may help to develop new starting points for therapeutic intervention.

The immigration of cells into adipose tissue follows precise molecular patterns that can be thought of as maps. "If you could prevent pDCs from entering fat, for example, you might also be able to prevent the resulting secondary diseases," Walzog explains.

Note: This article has been translated using a computer system without human intervention. LUMITOS offers these automatic translations to present a wider range of current news. Since this article has been translated with automatic translation, it is possible that it contains errors in vocabulary, syntax or grammar. The original article in German can be found here.

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