In severe COVID-19 patients, metabolism produces insufficient amounts of certain energy-rich compounds called ketone bodies. However, these energy carriers require two important types of cells in the immune system to effectively fight viruses. Perhaps this finding explains why some people fall more seriously ill than others. A study led by the University of Bonn and the University Hospital Bonn at least points in this direction. The results have now been published in the journal Nature, They also offer hope for new treatments.
When we fall ill, we often lose our appetite. It also has an effect on our metabolism: since it is no longer supplied with carbohydrates, it turns into burning fat. This creates energy-rich molecules called ketone bodies. And these can help our body deal with the virus better.
At least that is what the results of the current study suggest. “We found that patients with influenza infection produce significant amounts of ketone bodies, which are also members of the Immunosensation 2 Cluster of Excellence,” explains Professor Dr Christoph Wilhelm from the Institute of Clinical Chemistry and Clinical Pharmacology at the University Hospital Bonn. University of Bonn. “In contrast, we saw hardly any increase in COVID-19 patients, at least in those with a moderate or severe course.”
Furthermore, it was surprising that people infected with the coronavirus had lower levels of inflammatory messengers in their blood. This was especially true for interferon-gamma. It is a cytokine secreted by a specific group of immune cells, T-helper cells. These cells use it to summon the help of phagocytes and other defense troops of the immune system to fight the virus. For efficient production of IFN-gamma, however, helper T cells clearly require an adequate supply of ketone bodies. If it is lacking, they produce less interferon-gamma. In addition, helper T cells then die first.
Ketone bodies make the immune system more powerful
The researchers observed similar effects in another important group of immune cells, killer T cells. “They also need ketone bodies to function well and kill viruses effectively,” says Dr. Christian Bode, lecturer in the Department of Anesthesiology and Surgical Intensive Care Medicine at the University Hospital Bonn. Promotes the function of ketone bodies mitochondria, metabolic power house immune cells. This not only ensures better energy production, but also provides essential molecules for interferon production.
“Without an adequate supply of ketone bodies, on the other hand, killer T cells and helper T cells show signs of exhaustion,” Bode explains. “In this emaciated state, they can no longer perform their function adequately.” However, the researchers were able to regenerate immune cells to diseased mice on a ketogenic diet (a diet low in carbohydrates and protein) or by administering ketone bodies directly. The animals then had better success eliminating the virus and developed significantly less lung damage.
Hope for new treatment options
The results therefore raise hope for new treatment options as well. “It may be possible to increase the body’s power of its own defenses through targeted changes in diet,” Wilhelm says. “Whether it actually works now needs to be shown by further studies.” The researchers explicitly advise against self-use with dietary supplements or anorexia – these could potentially do more harm than good.
The new findings may be relevant for other infections as well. In the medium term, they may also contribute to new strategies to help the body fight tumors.
Participating Institutions and Funding:
In addition to the University Hospital and the University of Bonn, TU Braunschweig and the University Hospitals of Hanover, Zurich, Nijmegen and Essen were involved in the study. The study was funded by the German Research Foundation (DFG), the German Federal Ministry of Education and Research (BMBF), the European Research Council (ERC) and the Netherlands Organization for Scientific Research (NWO).
material provided by Bono University, Note: Content can be edited for style and length.