Cardiovascular disease is a major cause of morbidity and mortality in patients with Type 1 diabetes (T1D). In addition, cerebrovascular dysfunction contributes to the pathogenesis of stroke and cognitive impairment observed in humans with T1D. These consequences of T1D may be related to alterations in cellular networks that increase oxidative stress, and impair nitric oxide synthase (NOS) and potassium (K+) channel- dependent reactivity of cerebral vessels. We suggest that T1D impairs reactivity of cerebral vessels by altering the balance between key cellular networks responsible for governing oxidative stress, and thus reducing nitric oxide (NO) bioavailability and produce K+ channel dysfunction. We also have evidence suggesting that exercise training (ExT) may restore this balance. Our central hypothesis is that T1D alters the contribution of oxidative cellular networks governing cerebrovascular reactivity, and that ExT will alleviate cerebrovascular dysfunction during T1D via effects on these cellular networks. To test this hypothesis, the following aims are proposed.
In Specific Aim #1, we will test the hypothesis that the contribution of NOS and K+ channels in the regulation of cerebrovascular function is impaired in T1D and that ExT will alleviate/prevent this impairment.
In Specific Aim #2, we will test the hypothesis that T1D impairs NOS- and K+ channel-dependent responses of cerebral vessels via activation of cellular networks that lead to an increase in oxidative stress and that ExT can alleviate cerebrovascular dysfunction by influencing these critical networks.
In Specific Aim #3, we will test the hypothesis that alterations/manipulations in antioxidant pathways may contribute to impaired responses of cerebral vessels during T1D and that ExT can alleviate this impairment by influencing these antioxidant pathways.
In Specific Aim #4, we will test the hypothesis that ExT can reduce cerebral ischemic brain damage during T1D mainly via its influence on oxidative stress. Our studies will be the first comprehensive and integrative attempt to examine mechanisms that contribute to impaired reactivity of cerebral vessels during T1D and the therapeutic benefits of ExT on cerebral vessels and brain damage during T1D. We will use established techniques to examine in vivo reactivity of cerebral vessels coupled with new innovative molecular and biochemical approaches to determine the effects of T1D and ExT on the brain.
While T1D contributes to many disorders of the brain, including stroke, cellular mechanisms that account for the effects of T1D on the brain remain virtually unknown. ExT may be a valid therapeutic approach for the treatment of brain dysfunction during T1D, however, no studies have examined this approach for the treatment of cerebrovascular dysfunction during T1D. Our studies will be the first to examine the potential therapeutic benefits of ExT on brain function during T1D.
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