Within the next twenty years, 50% of all individuals in this country will be 50 years old or older, an aging time point that has been characterized in cross sectional data by the onset of cognitive decline. This shifting of the population to a proportionately greater number of older individuals has fueled concerns about the effects of aging and age-related diseases and their relationship to cognitive decline. One of the most common conditions affecting individuals as they age is hypertension, the incidence of which is 25% among all adults in the US., and greater than 50% among all adults over the age of 65. At present, this condition affects over 60 million people in the U S alone, of whom it is estimated 50% may be untreated. Moreover, evidence has accumulated to show convincingly that hypertension, in addition to aging, produces impairment in multiple domains of cognitive function, even at mildly elevated levels of blood pressure. In addition, hypertension is a major risk factor for cerebrovascular dementia which alone accounts for approximately 20% of all dementia and likely contributes to another 15% to 20% of the dementia cases. However, the mechanism by which hypertension induces neuropathological changes is poorly understood, in part because only limited animal models exist for studying these processes. The purpose of this project is to test a novel device for inducing hypertension in the non-human primate. The device is surgically implanted into the chest of the monkey surrounding the thoratic arota. The device can be adjusted externally to narrow the diameter of the arota (but not fully constricting it) resulting in increased blood flow and hypertension to the upper limbs and head. By adjusting the device gradually over a period of time, the blood pressure can be raised gradually until hypertension is induced. We will test this device in non-survival and short-term survival situations in five monkeys. They will be continuously monitored for blood pressure, body temperature, EKG and activity using radiotelemetry devices and values compare from pre-implant to post-implant levels. Finally, as part of a preliminary effort to understand the mechanism by which neuropatholoigical processes are induced in the brain, we will survey the brain and aorta for signs of pathology.
