AURORA, Colo. Researchers studying why arteries stiffen in postmenopausal women have found a specific chemical cofactor that dramatically improves vascular function.
Kerrie Moreau, Ph.D., Associate Professor of Medicine at the University of Colorado School of Medicine, discovered that BH4 or tetrahydrobiopterin plays a key role in arterial health of women. BH4 is a critical cofactor of the enzyme endothelial nitric oxide synthase or eNOS. The two combine to create nitric oxide which is highly beneficial to arterial health.
"Nitric oxide causes arteries to dilate, without it they are more constricted which can lead to arterial stiffening. That stiffening can cause high blood pressure, thickening of the left ventricle and increase the risk for stroke, heart disease and dementia" said Moreau, who works in the Division of Geriatrics at CU School of Medicine. "If there is not enough BH4, the eNOS enzymatic function does not work as well and less nitric oxide is produced. That leads to an increase in free radical formation or oxidative stress. Increased oxidative stress can decrease the amount of nitric oxide and BH4, creating a vicious cycle."
The study will be published in the American Journal of Physiology Heart and Circulatory Physiology.
Moreau, the lead researcher in the study, gave BH4 to estrogen-deficient, postmenopausal women and assessed them three hours later. She found that dilation of the arteries increased while stiffness decreased. When premenopausal women were given BH4, nothing happened.
Researchers also took two groups of postmenopausal women and gave one group a placebo and the other estrogen patches. They examined the results 48 hours later and discovered those who took estrogen experienced similar effects to those given BH4 while the women who received placebos experienced no changes. When the women who were taking estrogen were also given BH4 there was no further benefit.
|Contact: David Kelly|
University of Colorado Denver