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Session: Bioactives in Health and Disease (Oral 2)

(OR02-07-24) A Plant-Based Diet Prevented Coronary Microvascular Dysfunction (CMD) Independent of Hypertension in a Similar Manner to Gut Microbiota Depletion

Saturday, June 29, 2024
4:12 PM – 4:24 PM CT
Location:  W375C

    Presenting Author(s)

  • Rami S. Najjar, PhD

    Postdoctoral Fellow
    Georgia State University
    Atlanta, Georgia, United States

    Disclosure(s): No relevant financial relationship(s) with ineligible companies to disclose.

    • Co-Author(s)

  • PM

    Puja K. Mehta, M.D

    Emory University School of Medicine
    Atlanta, Georgia, United States

  • AG

    Andrew T. Gewirtz, PhD

    Professor
    Georgia State University
    Atlanta, Georgia, United States

Objectives: Hypertension is a risk factor for coronary microvascular dysfunction (CMD), the underlying cause of ischemia with non-obstructive coronary artery disease. CMD is associated with major adverse cardiovascular outcomes and improved therapeutics are needed. Plant-based diets (PBD)s are associated with a lower cardiovascular disease risk. Polyphenols likely mediate these protective effects, and polyphenol metabolism is regulated by the gut microbiota. Nonetheless, the therapeutic efficacy of diet has never been investigated in CMD. We investigated whether a plant-based diet (PBD) could improve CMD in a gut microbiota-dependent manner in an animal model of hypertension.

Methods: Four-week-old, female spontaneously hypertensive rats (SHRs) consumed a nutrient/fiber-matched control diet or a PBD comprising 4% each (w/w) of walnuts, black beans, red bell pepper, sweet potato, blueberries, Brussels sprouts, and lemon. Separately, animals on both diets consumed antibiotics (ABX) in drinking water to deplete the gut microbiota. Female Wistar-Kyoto (WKY) rats served as normotensive controls and consumed the control diet. Blood pressure was monitored every other week. After 12 weeks, coronary flow reserve (CFR) was assessed with echocardiograms utilizing intravenous adenosine infusion to measure microvascular function. Data were analyzed with one-way ANOVA followed by Dunnett’s post-hoc analysis.

Results: As expected, systolic blood pressure (SBP) was significantly higher in SHRs consuming the control diet (159 ± 12 mmHg) compared to WKY (117 ± 6 mmHg; P < 0.0001). Further, CFR was lower (1.8 ± 0.1) compared to WKY (2.3 ± 0.1; P < 0.003). Consumption of PBD or ABX in either diet did not significantly reduce SBP compared to control diet SHRs; however, CFR significantly improved in treatment groups (P ≤ 0.01) and was similar to WKY rats (P ≥ 0.78). Improved CFR occurred despite a significant reduction in ejection fraction, a measure of heart function, in all SHRs irrespective of treatment (P ≤ 0.001).

Conclusions: A PBD improved CMD despite the persistence of hypertension. A clear role for the gut microbiota exists in CMD considering improved CFR with ABX. Clinical trials testing the impact of PBD on cardiovascular outcomes in patients with CMD are warranted.

Funding Sources: This study was funded by USDA-NIFA.