There is an new connection between obesity and hypertension, between the cardiovascular system and the immune response: immune cells called eosinophils. Recent discoveries revealed that these cells help regulate blood vessel function but become mysteriously sparse in obese individuals.
Eosinophils, which Dr. Sheena Cruickshank said are ““traditionally overlooked,” are white blood cells specifically designed to fight parasites, and they are also linked to some allergies, autoimmune diseases, and cancer subtypes. From the University of Manchester, Cruickshank is the lead researcher of a new Scientific Reports study on a new role for eosinophils.
According to Cruickshank’s findings, fighting parasites is simply an eosinophil’s day job; by night the cells are plentiful in the fatty layer of tissue surrounding blood vessels, a space called the perivascular adipose tissue (PVAT). The PVAT regulates blood vessel function by reducing artery contraction.
"This type of immune cell is present in many parts of the body and was once thought to just act in parasitic infections and allergies, but it's fast becoming clear that they have a significant effect on lots of aspects of health and immunity,” Cruickshank said.
While examining obese mice, researchers found that eosinophil levels were significantly reduced in their PVAT, causing regulatory dysfunction and ultimately leading to obesity-related conditions like type 2 diabetes and hypertension.
Apparently the connection between drooping eosinophil levels and complications from obesity is due to these immune cells releasing of nitric oxide and adiponectin, a collagen-like protein involved in glucose and lipid metabolism in insulin-sensitive tissues. These secretions are important for healthy blood vessel function, explaining, at least in part, the connection between obesity and its complications.
The new discovery offers a new solution for drugs to target obesity, hypertension, and type 2 diabetes. Replenishing the PVAT with eosinophils could potentially relieve some of the effects caused by excessive weight gain.