Exercise, Hypertension, and Gut Dysbiosis in African Americans

African Americans (AA) have the greatest burden of hypertension and elucidating the pathogenesis of this racial disparity is important for amending treatment strategies. Gut microbial dysbiosis has been linked to hypertension and has been characterized as low microbial composition of short chain fatty acid (SCFA) producing microbes. Reduced gut SCFA production has been observed in AA with disease, such as glucose intolerance and vitamin deficiency, and may be related to the pathogenesis of hypertension in this group. Preliminary data show that aerobic exercise improves the gut microbial profile and increases SCFA production in animal models and humans. Additional preliminary data show that the SCFA butyrate attenuates dysfunction in AA endothelial cells suggesting a role for SCFA in endothelial/vascular function. The proposed studies have been constructed to fill a critical void in our understanding of the pathogenesis of hypertension in AA involving the gut microbiome. The investigators hypothesize that lower SCFA production is associated with blood pressure in AA and exercise will be effective in reducing blood pressure by coupling improvements in gut microbial health (↑SCFA production) and vascular health. The proposed research will: 1) quantify the relationship between gut dysbiosis (reduced gut and circulating SCFA) and blood pressure in AA with hypertension and 2) quantify the impact of aerobic exercise training on gut microbial community structure, identify adaptable SCFA microbes related to blood pressure, blood concentrations of SCFA, and blood pressure in AA. The research will provide novel insight into the pathogenesis of hypertension, particularly in the health disparate AA population, and will facilitate the development of future mechanistic studies to advance the clinical communities understanding of the "gut-vascular axis" concerning endothelial function and vascular disease in AA.

Inclusion criteria

• Sedentary (regular aerobic exercise frequency ≤2 times per week and duration ≤20 minutes per session; sedentary profession);
• 30-50 years of age;
• Control normotensive (systolic BP: 90-120 mmHg/diastolic BP: 60-80 mmHg)
• Elevated to Stage 1 Hypertension (systolic BP: 120-129 mmHg/diastolic BP: 80-89 mmHg) and/or stage 1 hypertension (systolic BP: 130-159 mmHg/diastolic BP: 90-99 mmHg).

Exclusion criteria

Diagnosed with any of the following:

• Uncontrolled hypertension, stroke, history of heart attack, heart disease;
• Metabolic disease (diabetes mellitus);
• Inflammatory diseases (inflammatory bowel disease(s), rheumatoid arthritis, and systemic lupus erythematosus);
• Kidney stones or gallbladder problems;
• Kidney disease;
• Liver disease;
• Lung disease;
• Cancer within the previous 6 months; (11) pregnant females;
• Peripheral vascular disease;
• Taking hypertension medications or those known to affect inflammation or metabolic function (anti-inflammatories, statins, thyroid medication) in the past 1 month;
• Currently smoking;
• Other conditions that would exclude vigorous exercise (>2mV ST-segment depression or CVD signs and symptoms during the screening graded exercise test).