salt and immune system

Recent research reveals the extent of an important relationship between salt and the immune system.

Excessive salt intake, common in many Western societies, is not only detrimental to blood pressure and the cardiovascular system, but can also negatively affect the immune system.

This is indicated by the results of a study carried out by the international team of Dominik Müller, from the Max Delbrück Center for Molecular Medicine, dependent on the Helmholtz Association in Germany, as well as Beatriz Côrte-Real and Ibrahim Hamad, both from the University of Hasselt in Belgium.

Müller and his colleagues have found that too much salt can disrupt key immune regulators, called regulatory T cells, by impairing their energy metabolism. The finding could provide new clues about the development of autoimmune and cardiovascular diseases.

In a previous study, it was revealed that too much salt in our diet can negatively affect the metabolism and energy balance of certain types of innate immune cells called monocytes and macrophages, preventing them from functioning properly. It was also shown that salt triggers dysfunctions in mitochondria, the powerhouses of our cells. That led the authors of the new study to wonder whether excessive salt intake might also create a similar problem in adaptive immune cells, such as regulatory T cells.

Regulatory T cells are an essential part of the adaptive immune system. They are responsible for maintaining the balance between normal functioning and unwanted excessive inflammation. Regulatory T cells are sometimes referred to as the “immune police” because they keep the bad guys at bay, and also ensure that immune responses occur in a controlled manner without harming the host organism, such as when police prevent a crowd from enraged and out of control lynch innocent people whom she mistakenly believes guilty of something.

It is believed that this malfunction of regulatory T cells is related to the development of autoimmune diseases, for example multiple sclerosis. Recent research has identified problems in the mitochondrial function of regulatory T cells from patients with autoimmunity, but the contributing factors remain unclear.

In the new study, excess sodium has been found to sabotage the work of regulatory T cells by altering cell metabolism by interfering with mitochondrial energy generation. This mitochondrial problem appears to be the initial step in how salt alters regulatory T cell behavior, leading to changes in gene expression that showed similarities to those seen in dysfunctional regulatory T cells in autoimmune diseases.

Salt alters the function of the immune system’s regulatory T cells: their mitochondria temporarily produce less energy, thus altering cellular metabolism. (Image: Felix Petermann, Max Delbrück Center)

Even a short-term disturbance of mitochondrial function had lasting consequences on the fitness and immunoregulatory capacity of regulatory T cells in several experimental models. The new findings suggest that sodium may be a contributing factor to regulatory T cell dysfunction, thus potentially playing a role in the development of several diseases, although this needs to be confirmed in further studies.

The new study is titled “Sodium perturbs mitochondrial respiration and induces dysfunctional Tregs.” And it has been published in the academic journal Cell Metabolism. (Fountain: NCYT by Amazings)