If appetite-promoting AgRP neurons are chronically suppressed, resulting in less appetite and a lighter body weight, T-cells tend to promote inflammation-like processes resulting in autoimmune responses that may lead to multiple sclerosis and other autoimmune diseases, scientists at Yale School of Medicine discovered.
In the peer-reviewed journal, Proceedings of the National Academy of Sciences (PNAS), the authors explained that neurons that regulate hunger in the CNS (central nervous system) also control the functions of immune cells, suggesting that eating behavior is a defense mechanism against infections and the development of autoimmune disease.
Over the last few years, there has been a steady increase in the number of Americans with autoimmune diseases. These illnesses occur when the person’s own immune system attacks healthy tissue and cells is if they were harmful pathogens.
How different types of T-cells interact are at the heart of fighting off infections as well as the development of autoimmune disorders.
Lead author Tamas Horvath, the Jean and David W. Wallace Professor of Biomedical Research and chair of comparative medicine at Yale School of Medicine, said:
“We’ve found that if appetite-promoting AgRP neurons are chronically suppressed, leading to decreased appetite and a leaner body weight, T cells are more likely to promote inflammation-like processes enabling autoimmune responses that could lead to diseases like multiple sclerosis.
If we can control this mechanism by adjusting eating behavior and the kinds of food consumed, it could lead to new avenues for treating autoimmune diseases.”
Horvath and team carried out an animal experiment in which mice had Sirt1 – a signaling molecule that controls the hunger-promoting neuron AgRP in the hypothalamus – knocked out. These mice, referred to as “Sirt1-deficient mice”, had reduced regulatory T-cell function and greater effector T-cell activity, making them more vulnerable to developing an animal-equivalent of multiple sclerosis.
Horvath said:
“This study highlights the important regulatory role of the neurons that control appetite in peripheral immune functions. AgRP neurons represent an important site of action for the body’s immune responses.”
The authors believe that losing weight after using medications that give the patient a sensation of fullness may have unexpected effects on the spread of autoimmune disorders.
There is a fine balance between to little and too much activity in our immune system. Too little and we become susceptible to infections and cancer, too much and our risk of developing autoimmune diseases and allergies increase.
The journal Nature published three studies online in March 2013 which suggest that how much salt we consume may influence this balance by indirectly encouraging the overproduction of immune cells.
The three studies focused on T cells.
The researchers said further studies need to be carried out to determine what the link is between high salt intake and autoimmune diseases.
Written by Christian Nordqvist