As per the media reports in April 2020, a study published in Nature, conducted by Ajith Vasanthakumar, Department of Microbiology and Immunology and Peter Doherty, Institute for Infection and Immunity, University of Melbourne, Australia, finds crucial differences in the way the immune system acts in the body fat of male and female mice. The researchers studied the visceral adipose tissue (VAT) and found key differences.
Key Findings of the Study
Key finding of the study are as follows:
(i) The perigondal VAT taken from male mice had many more regulatory T cells (Treg) than that of female mice.
(ii) These cells play a role in controlling immune response to the self and external cells to protect body from autoimmune diseases like rheumatoid arthritis or lupus.
(iii) The treg cells in the male VAT showed a distinct phenotype, functional parameters and gene expression pattern, compared to Treg cells in female VAT.
(iv) Elevated expression of inflammatory genes in male VAT was found, especially in stromal cells that made the cytokine IL-33, exclusive to male VAT.
(v) Like male mice, men are more susceptible to metabolic diseases, such as type 2 diabetes, which is linked to the presence of comparatively higher adipose tissue inflammation in men.
(vi) Human adipose tissue (omental) harbours Treg cells of a phenotype similar to the one found in mice. Thus, the difference found in Treg cell distribution in the visceral adipose tissue of male and female mice may also be there in humans.
About Visceral Adipose Tissue
Visceral adipose tissue (VAT) is fat tissue that is found in the abdominal region, surrounding various organs, including perigonadal VAT which surrounds the ovaries in females and testes in males. It was simply regarded as an energy storage (organ) but its endocrine functions have also been highlighted, i.e., it secretes adipokines and hormones that play key roles in energy balance and metabolism.
Implications of the Study
Generally, male mice are used when studying metabolic disease. Now, it becomes clear that findings of tests on males will not hold equally good for males and females. Similarly, it would also change the practice of recruiting men only and would pave the way for tailoring drugs to gender in the future.