Scientists at research center (CIMA) and the University Clinic of the University of Navarra have analyzed the role of leptin, a hormone secreted by fat cells, in order to delve into the causes of hypertension associated with obesity.

The Journal of Hypertension has published in its latest issue issue this work, developed by Amaia Rodríguez, Gema Frühbeck, Javier Gómez-Ambrosi, Victoria Catalán, Neira Sáinz, Javier Díez, Guillermo Zalba and Ana Fortuño. This is a joint research directed by the area of Cardiovascular Sciences of the CIMA and the laboratory of research Metabolic of the University Clinic.

As Amaia Rodríguez explains, leptin offers a double benefit: it acts on the brain, reducing appetite and body weight, and contributes to regulating blood pressure. "However, it does not exert its function in obese and hypertensive individuals. Although they have high levels of the hormone in the blood, it does not work properly," he adds.

Metabolic syndrome

The study concludes that this resistance to leptin originates when it loses its ability to relax blood vessels and counteract the effects of angiotensin II in the aorta, a potent vessel constrictor involved in the development of hypertension. "This increases the sympathetic activity exerted by the hormone in the brain, favoring the onset of the disease," explains the biologist.

At research it was found that in spontaneously hypertensive rats, leptin lost its ability to dilate the vessels, despite the fact that these animals have a greater number of receptors for the hormone in the aorta. The rats showed alterations known as metabolic syndrome: hypertension, increased body weight and insulin resistance (related to diabetes). "The high levels of leptin found could favor the development of hypertension, which confirms the data of other authors," emphasizes Amaia Rodríguez.