Gut Butyrate and Blood Pressure in African Americans

African Americans have the greatest burden of hypertension. Recently, the short-chain fatty acid, butyrate, has been reported to have some effect on blood pressure. Butyrate is not normally ingested since it is made by bacteria in the gut as a byproduct of fiber fermentation. In this proof of concept study, the investigators will investigate the effect of butyrate absorbed in the gut (via the participant self-administering an enema with butyrate) has on blood pressure.

Description: African Americans (AA) have the greatest burden of hypertension. Recently, gut microbial dysbiosis (a term that describes a poorly diverse gut microbial profile and lower short-chain fatty acid (SCFA) production) has been linked to hypertension and may be involved in the pathogenesis of hypertension in African Americans. African Americans have been reported to have lower gut SCFA and SCFA can reduce blood pressure. This is a proof of concept pilot study to determine the relationship between gut SCFA and blood pressure (BP). Delivery of butyrate to the gut will be via enema. Objectives: The objectives of this research are to 1. Identify gut microbial taxa (SCFA butyrate-producing microbes) and circulating butyrate levels associated with hypertension via a cross-sectional design in AA without and with hypertension. 2. Quantify the relationship between SCFA (butyrate) absorption into the bloodstream and subsequent changes in blood pressure in a 24-hour period after delivering butyrate into the gut via enema. Participants: African Americans males and females ages of 30-50 without hypertension (normal BP/healthy control; systolic BP: 90-129/ diastolic BP: 60-89mmHg) and with hypertension (systolic BP: 130-159 mmHg/ diastolic BP: 80-99 mmHg) that do not take anti-hypertension medication will be recruited. Description of Study: There are 2 groups; control (without hypertension; BP: 90-129/60-89mmHg; 5 male/5 female, n=10) and experimental (with hypertension; BP 130-159/80-99 mmHg; 5 male/5 female, n=10). Normotensive participants (control group) will be age (±1 year) and sex-matched to hypertensive group participants. All participants (control and experimental groups; 5 male/5 female) will provide stool and blood samples, and complete 24-hour (hr) ambulatory blood pressure (ABP) monitoring to compare the abundance of fecal butyrate-producing microbes, circulating (blood) butyrate concentrations, and average blood pressure responses during the day and overnight. Individuals in the control group will only participate in donating stool (1-time) and a blood sample (1-time) and wearing a 24-hr ABP monitor (1-day). In a crossover blinded randomized controlled pilot study, the 10 hypertensive AA subjects (5 male/5 female) will be randomized to self-administer a sodium butyrate (80mmol butyrate in 0.9% saline, 60 ml total) or control (low dose) butyrate (5mmol butyrate 0.9%, 60 ml total) enema 1 week apart (7 days). Subjects will provide a stool sample before each study day (2 total), have their BP measured via ABP monitor, submit to a blood draws (pre-enema-baseline), self-administer the randomized enema, submit to a 30 min \& 60 min post-enema blood draw, and wear the 24-hour ABP monitor for the remainder of that day. Subjects will be provided with written and verbal instructions on how to self-administer the enema. The dietary supplement (sodium butyrate) will be compounded by a local pharmacy (Custom Care Pharmacy - 109 Pisgah Church Rd. Greensboro, NC) into an enema at the concentrations listed above.