Peripheral Vascular Effects of Sulfhydryl-containing Antihypertensive Pharmacotherapy on Microvessels in Humans

Study Summary

High blood pressure can cause physical changes to the blood vessels of the body (remodeling). If a person who has high blood pressure also has a lot of blood vessel remodeling with their condition, they are more likely to have poor results with medical treatment for hypertension. The researchers examine the impact of different classes of drugs that doctors use to treat high blood pressure (hypertension) on blood vessel remodeling. Some drugs that doctors prescribe for their patients contain a "sulfhydryl group" (a sulfur atom bonded to a hydrogen atom). Drugs that have the sulfhydryl group may reduce blood vessel remodeling more that drugs that do not. For this study, participants who have high blood pressure perform the experiments, take a drug for 16-weeks to lower blood pressure, and repeat the experiments. The researchers randomly assign one of three drugs to participants who have high blood pressure: a diuretic ("water pill"), a drug containing a sulfhydryl (SH) group, or a drug that does not contain a sulfhydryl group. Participants who do not have high blood pressure perform the experiments, but do not take any of the drugs. In some of our experiments, the researchers use a technique called "microdialysis" (MD). With MD, the researchers perfuse some research drugs into the skin on the forearm through tiny tubing that mimics capillaries. These MD drugs mimic or block substances the body naturally makes to control the small blood vessels in the skin. The drugs remain in nickel-sized areas around the tubing and do not go into the rest of the body. The researchers also analyze very small skin samples (skin biopsy) obtained from the forearm. Lastly, the researchers use a standard technique called "flow mediated dilation" (FMD) that uses blood pressure cuffs and ultrasound to look at the health of larger blood vessels in the body. FMD includes placing a small tablet of nitroglycerin under the tongue during part of the test.

Primary Outcome

This measurement is performed using a laser Doppler flow meter. The flow meter produces a non-invasive qualitative and dimensionless index of blood flow in blood vessels during the localized perfusion of the endothelium-dependent vasodilatory acetycholine in a dose response fashion. The results are the differences in the area under the curve units=(laser Doppler flux/MAP)\*logAch concentration

Interventions

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