Researchers have identified the enzyme responsible for
obesity-related hypertension that can lead to severe health issues such
as heart attacks, kidney failure, organ damage, and weakened or ruptured
blood vessels.
Obese individuals have an increased risk of diabetes and cardiovascular
disease, including hypertension and the findings show promise of new
treatment options.
"By comparing genetically obese rats to lean rats, we discovered that
obese animals were deficient in the amino acid arginine due to elevated
activity of the enzyme arginase, which breaks down this molecule," said
lead study author William Durante, professor at University of Missouri
School of Medicine.
Although arginase is present throughout the body, it is primarily found
in the liver. Its role is to assist in the breakdown of ammonia, which
is eventually flushed out during urination.
However, Durante's team found significantly increased arginase activity
within blood vessels and in the blood of obese rats compared to lean
animals.
"The problem with this development is that arginase depletes arteries
and blood of arginine, which is needed to generate nitric oxide,"
Durante said.
"Nitric oxide is a gas formed from arginine that relaxes blood vessels
and lowers arterial blood pressure. The destruction of arginine by
arginase reduces nitric oxide levels, leading to the constriction of
blood vessels and high blood pressure," he pointed out.
Using two methods to correct the arginine deficiency, Durante's team
first supplemented the diet of obese animals with the amino acid
L-arginine which is commonly found in red meat, poultry, fish and dairy
products.
The second method involved using drugs that block the activity of
arginase. Although both approaches restored nitric oxide production and
reversed hypertension in obese rats, the use of arginase-inhibiting
drugs may be a better solution.
"Blocking arginase activity offers a more specific approach in treating
hypertension, because you are directly targeting the underlying
biochemical defect in obesity," Durante said.
The study appeared in the journal Obesity.
