This study will assess if telmisartan, an FDA approved blood pressure medication, may also have beneficial effects on Alzheimer's disease (AD) prevention in African Americans, who are at high risk for Alzheimer's disease. Blood pressure medications known as angiotensin-receptor blockers have been associated with reduced risk of Alzheimer's in Caucasians because they act on the renin-angiotensin system (RAS), a key regulator of blood pressure in the body and the brain. The drugs appear to slow the progression of the disease by affecting flow of blood and the amount of plaque in the brain, but these benefits have not been tested in African Americans. The investigator will evaluate if telmisartan is able to influence the renin-angiotensin system in the brain and produce favorable effects on brain blood flow and enzymes that cause the brain plaques in Alzheimer's disease.The investigator will assess the mechanism by which telmisartan modifies the brain renin angiotensin system, cerebrospinal fluid amyloid-β, cerebral blood flow (CBF) and inflammatory markers in hypertensive African Americans.
