INSULIN RESISTANCE AND CARDIOVASCULAR RISK FACTORS

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This K-24 application includes a mentoring plan and two research components which are linked together by the common theme of insulin resistance and cardiovascular risk factor clustering. In part 1 of the research plan, we plan to continue work under the current R01 and a subsequent competitive renewal to test the hypothesis that fatty acids and angiotensin induce a synergistic enhancement of oxidative stress in humans. The three specific aims are to determine (1) the effects of raising fatty acids and angiotensin singly and in combination on markers of platelet PKC activity and oxidative stress (2) the effects of a low NaCl diet, which raises plasma angiotensin II, on markers of oxidative stress in obese hypertensive patients during treatment, with an AT1 receptor antagonist compared to placebo 3) which protein kinase C (PKC) isoform isoform(s) are stimulated by oleic acid and lead to the generation of reactive oxygen species and activation of extracellular signal-regulated kinases in human aortic smooth muscle cells by using antisense oligonucleotides to specific PKCs. Each of these specific aims will be addressed using methods which are well established in our patient-oriented clinical and bench research. In part 2, with the support of this K-24 Award, we plan to extend the generalizability of our findings to the wider community and by addressing important gaps in the literature on low birth weight and cardiovascular risk. We will test the hypothesis that low birth weight contributes to cardiovascular risk and salt sensitivity in a biracial sample of young adults at two college campuses in South Carolina. Three specific aims will be addressed to determine the relationships of low birth weight (<2500 grams) to (1) metabolic components of insulin resistance (oral glucose tolerance test and dyslipidemia (NMR lipid profile) (2) hemodynamic components of the insulin resistance syndrome including laboratory and 24-hour ambulatory blood pressure (BP), baroreflex sensitivity (cross spectral analysis of systolic BP and heart rate), proximal and distal arterial compliance (HDI pulse-wave) and post-ischemic forearm vascular resistance (venous occlusion plethysmography). (3) Salt sensitivity defined by the differences in BP on 180 vs. 80 mmol/d NaCl diets. All of the mentoring activities, which would be supported by the K-24 Award, also relate to various facets of the insulin resistance syndrome. "Access to excess" calories and labor saving devices has produced an epidemic of obesity and cardiovascular risk factors related to insulin resistance. While lifestyle changes are important and the PI and his colleagues work diligently in this area most people are unable to normalize their risk through lifestyle changes alone. We believe that a better definition of the pathophysiological common denominators and key intracellular signaling events mediating these effects will provide the basis for novel therapeutic approaches to cardiovascular disease prevention.