Abstract P140: The Role of Pumpkin Flesh in Reducing Mean Arterial Pressure in a Genetic Rat Model for Hypertension

Abstract

Objective: ACE inhibitors (ACEi) remain the most commonly prescribed medication; lowering blood pressure, increasing bradykinin levels and decreasing cardiac hypertrophy. A demographic-specific bradykinin sensitivity renders African-American patients on ACEi with elevated risk of angioedema. This increased risk has led a search for natural ACEi from functional foods or natural resources, one of which being pumpkin. In Sprague Dawley rats with L-NAME induced hypertension, pumpkin seed oil significantly reduced systolic blood pressure. As a promising source of β-carotene, phenolics and a beneficial fatty acid profile, this study aimed to examine the potential of pumpkin flesh and seed in regulating blood pressure management in a genetic model for hypertension. Methods: Spontaneously Hypertensive Rats (SHR) and Wistar-Kyoto rats (WKY), aged 6 weeks, were fed one of the following diets for 8 weeks: 4% pumpkin flesh (PF), 4% pumpkin seed (PS), control diet (Ctrl), and an SHR-Captopril treated group (Cap). Non-invasive blood pressure monitoring was employed for weekly measuring of mean arterial pressure (MAP). Upon 8 weeks of treatment, animals were euthanized for structural analysis of cardiac hypertrophy (Heart weight to tibial length ratio). Left ventricular mRNA expression of ANP and BNP was quantified using quantitative RT-PCR techniques. Results: At 8 weeks, MAP in SHR-PF and SHR-PS groups was significantly reduced by 23% (p=0.0135) and 27% (p=0.0018) respectively, compared to SHR-Ctrl. Heart weight ratios showed no significant difference between SHR-Ctrl and SHR-PF or SHR-PS, while SHR-Cap heart weight significantly decreased by 15% (p=0.0028) in comparison to SHR-Ctrl. Additionally, increased mRNA expression of both ANP and BNP was observed in the SHR-PF group in comparison to WKY-Ctrl. Conclusions: The reduction of blood pressure observed in response to pumpkin-based diets suggests an alternative pathway of blood pressure control independent of ACE inhibition. This potential new pathway elucidates the health promoting capabilities of pumpkin as an alternative blood pressure treatment for all demographics.