Thymus Monitors Healthy Pregnancy

Highlights :

• Tregs are specialized cells of the immune organ – thymus
• Tregs are responsible for a healthy pregnancy and deal with physiological changes that arise during pregnancy
• The cells also help in preventing gestational diabetes through a thymus receptor, RANK
• This draws the view of the thymus as an active and dynamic organ required to safeguard pregnancies

The female sex hormones instruct the thymus to produce "Tregs", the specialized cells to deal with psychological changes that arise during pregnancy. The study was carried out by scientists from IMBA, the University of British Columbia, the Karolinska Institute and the Medical University of Vienna.

In this study, it was also found that RANK, a receptor expressed in a part of the thymus called the epithelium, is the key molecule behind this mechanism.

Thymus in Pregnancy

The thymus is the key organ of the immune system where specialized immune cells called T lymphocytes mature. The T cells help to combat pathogens and cancer. Regulatory T cell or Treg is a vital T cell subset produced in the thymus.

The primary role of Treg is to regulate other immune cells to fight pathogens.

"The absence of RANK prevented the production of Tregs in the thymus during pregnancy. That resulted in fewer Tregs in the placentas, leading to elevated rates of miscarriage," says the study's lead author Magdalena Paolino, a former postdoctoral fellow at IMBA, who now heads, since 2017, her laboratory at the renowned Karolinska Institutet in Sweden.

The study has discovered that the Tregs are responsible for preventing inflammation and controlling glucose levels in the body.

Pregnant mice lacking RANK had high levels of glucose and insulin in their blood and many other indicators of gestational diabetes including, larger-than-average young ones.

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To add surprise, administering thymus-derived Tregs isolated from normal pregnancies to the RANK-deficient mice reversed all the mice's health issues, including miscarriage and maternal glucose levels, and also normalized the body weights of the pups.

“The thymus changes massively during pregnancy and how such rewiring of an entire tissue contributes to a healthy pregnancy has been one of the remaining mysteries of immunology. Our work over many years has now not only solved this puzzle - pregnancy hormones rewire the thymus via RANK - but uncovered a new paradigm for its function: the thymus not only changes the immune system of the mother so it does not reject the fetus, but the thymus also controls metabolic health of the mother. This research changes our view of the thymus as an active and dynamic organ required to safeguard pregnancies," says the study's senior author Josef Penninger, IMBA group leader and founding director, who is now director of the Life Sciences Institute of the University of British Columbia.

Tips for a Healthy Pregnancy

• Eat foods rich in folate, iron, fiber, protein, and calcium
• Track your weight gain
• Drink fluids, mainly water, to avoid constipation
• Avoid alcohol, raw or undercooked fish, meat, and poultry
• Avoid consumption of soft cheeses
• Limit caffeine intake
• Practice moderate-intensity aerobic activity

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References:

1. Health Tips for Pregnant Women - (https://www.niddk.nih.gov/health-information/weight-management/healthy-eating-physical-activity-for-life/health-tips-for-pregnant-women)
2. 36 Tips for a Healthy Pregnancy - (https://health.ucsd.edu/news/features/pages/2016-01-05-36-pregnancy-tips-listicle.aspx)
3. "RANK links thymic Tregs to fetal loss and gestational diabetes in pregnancy", Pinto et al, Nature, 2020

Source-Medindia