Abusing salt is harmful to health and different scientific studies have shown its negative effects on the body, including the brain. The problem is that many foods contain hidden salt and it is common for us to exceed the amount recommended by the World Health Organization (WHO) in our usual diet, which is a maximum of 5 g per day. Excess sodium can raise blood pressure levels and increase cardiovascular risk, but a new study has also shown that it can impair the immune system.
An international team of researchers, coordinated by scientists from the VIB Center for Inflammation Research and Hasselt University in Belgium and the Max Delbrück Center for Molecular Medicine in Germany, has discovered that salt can influence energy metabolism in T cells. regulators and alter these important immune regulators. The results of this work have been published in Cell Metabolism and can serve as a basis for studying how cardiovascular and autoimmune diseases originate and develop.
A few years ago, research conducted by teams of scientists led by Professor Dominik Müller at the Max Delbrück Center and Center for Clinical and Experimental Research, a joint institution of the Charité—Universitätsmedizin Berlin and Max Delbrück Center (ECRC) in Berlin, and Professor Markus Kleinewietfeld at the VIB Center and Hasselt University found that eating too much salt can negatively influence metabolism and energy balance in some types of innate immune cells called monocytes and macrophages and prevent them from functioning properly.
These scientists also showed that salt alters the functions of mitochondria, which are the powerhouses of our cells. These findings made the research groups wonder if excessive salt intake could cause a similar problem in adaptive immune cells such as regulatory T cells.
Excess salt alters the adaptive immune system
Regulatory T cells, also known as Tregs, are a key part of the adaptive immune system, maintaining the balance between normal function and excessive inflammation that can lead to health problems. Tregs are sometimes referred to as the ‘immune police’ because they keep enemies such as autoreactive immune cells at bay and ensure that immune responses occur in a controlled manner and do not harm the host organism.
Salt can influence energy metabolism in regulatory T cells and disrupt these important immune regulators
Scientists believe that dysregulation of Tregs is related to the development of autoimmune diseases such as multiple sclerosis. Recent studies have identified problems in the mitochondrial function of Tregs in patients with autoimmunity, but the risk factors are not well understood.
“Considering our previous findings that salt affects monocyte and macrophage mitochondrial function, as well as new observations on mitochondria in Tregs from autoimmune patients, we wondered if sodium might cause similar problems in Tregs from healthy volunteers,” he said. Müller, who is co-director of the Hypertension-Mediated End Organ Damage Laboratory at the Max Delbrück Center and ECRC.
Previous research results had also shown that excess salt could affect Treg function by inducing an autoimmune-like phenotype; that is, too much salt makes Treg cells resemble those implicated in autoimmune conditions, but exactly how sodium affected Treg function had not yet been discovered.
The new international study has now found that sodium disrupts Treg function because it alters cellular metabolism through interference with mitochondrial energy generation. This mitochondrial problem appears to be the first step in the way that salt modifies Treg function, leading to changes in gene expression that have similarities to those of dysfunctional Tregs in autoimmune conditions.
Even a short-term disruption of mitochondrial function had long-lasting consequences for the fitness and immune regulation capacity of Treg cells in several experimental models. These findings suggest that sodium may contribute to Treg dysfunction and may play a role in several diseases, although further studies are needed to confirm this.
“Better understanding of the underlying molecular mechanisms and factors that contribute to Treg dysfunction in autoimmunity is an important issue in this field. Since Tregs also play a role in diseases such as cancer or cardiovascular disease, further exploration Such sodium-induced effects may offer novel strategies to alter Treg function in different types of diseases,” says Kleinewietfeld, who heads the VIB Laboratory for Translational Immunomodulation. “However, future studies are needed to understand the molecular mechanisms in more detail and to clarify their possible relationship with the disease.”
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