AUGUSTA, Ga. - Some of the first information about how fat causes hypertension have been identified by researchers who say the findings should one day help identify which obese people and maybe some thin ones too are at risk for hypertension and which drugs would work best for them.
Medical College of Georgia researchers have found that deleting or mutating the gene PTP1B puts mice at risk for hypertension by interfering with an endogenous mechanism that should help prevent it. The findings are published in the Sept. 1 issue of the American Heart Association journal Circulation.
"In a normal individual gaining weight, PTP1B should increase and they would be protected in theory from hypertension," says Dr. David Stepp, vascular biologist at the MCG Vascular Biology Center, co-director of the Diabetes & Obesity Discovery Institute and the study's corresponding author.
"But if you don't have a good copy of PTP1B and you become obese, then you are going to have a problem. So in theory this gene can segregate the obese people who will become hypertensive and those who won't."
Knowing the gene's status could also one day help physicians better select an antihypertensive medication for those who do.
A key player is the hormone leptin, produced by fat cells. Overweight individuals generally produce more of the hormone that essentially revs up the body, suppressing appetite and increasing metabolism so you won't get fatter. But leptin also increases blood pressure by activating the sympathetic nervous system, the so-called fight-or-flight response. Mutated or missing PTP1B dramatically increases leptin's negative effects.
MCG scientists studying how blood pressure got the message to increase found leptin also provides protection against high pressures by turning off the signaling pathway that squeezes blood vessels and drive pressures up in a process called adrenergic desensitization.
|Contact: Toni Baker|
Medical College of Georgia