Obesity is a major risk for hypertension or high blood pressure, which in turn increases the risk of cardiovascular diseases. But until now, there has been no precise explanation for the hypertension that follows weight gain.
Researchers found that the hormone leptin links obesity and high blood pressure – but some people who lack or cannot process the hormone do not have high blood pressure, despite being obese.
In a new study published in the journal Cell, researchers from Monash University in Melbourne, Australia, and the University of Cambridge in UK, describe how they found the hormone leptin is the link between obesity and increased blood pressure.
Leptin is a hormone that regulates the amount of fat that is stored in the body. It is released by fat cells and circulates in the bloodstream to reach the brain, where it controls signals that trigger storage of energy in fat reserves and also the release of energy from those reserves.
As well as controlling energy expenditure, leptin also adjusts the sensation of hunger, which is why it is referred to as the “satiety” hormone.
For their study, the team – led by Professor Michael Cowley of Monash University and Professor Sadaf Farooqi of the University of Cambridge – compared healthy mice and humans with counterparts who have problems producing or processing leptin.
They found that an increase in leptin in diet-induced obese mice drove an increase in their blood pressure – but not if they were deficient in leptin, or could not process it because their brains lacked leptin receptors.
The team found a similar effect in humans. Some people, who lacked leptin or leptin receptors because of a genetic disorder, had low blood pressure, despite being obese.