Diabetes makes blood vessels hard to relax

AUGUSTA, Ga., Feb. 1 (UPI) -- One way diabetes is bad for your blood vessels is by creating too much competition for an amino acid that helps blood vessels relax, U.S. researchers found.

Lead author Dr. Maritza Romero, a post-doctoral fellow at the Medical College of Georgia, said the enzyme arginase breaks down the amino acid L-arginine to urea, which helps the body eliminate toxins resulting from the proteins eaten. Diabetics have a lot of arginase activity, which means they use a lot more L-arginine.

It also means too little L-arginine is available to help nitric oxide synthase make nitric oxide, the powerful vasodilator that helps blood vessels relax, Romero said.

The researchers also found the amino acid, L-citrulline, as well as statins -- compounds known to lower cholesterol -- prevent elevation of arginase activity.

Their findings, published in Circulation Research, help explain why L-arginine supplement, marketed to treat hypertension, chest pain, heart failure and more, may not work long-term.