(PTFS22-05-24) Daily Supplementation With Blackberries and Raspberries Favorably Modulates Blood Pressure and Gut Microbiota in Ang II-Treated Male Rats

Objectives: High blood pressure is a major modifiable risk factor for cardiovascular disease, the leading cause of death worldwide, and has been associated with gut dysbiosis. Berries are rich in nutrients and phytonutrients and have been reported to exert anti-hypertensive effects as well as to modulate the intestinal microbiota. Therefore, the objective of this study was to determine the impact of daily consumption of blackberries (BL) and raspberries (RB) on the intestinal microbiota of angiotensin (Ang) II-treated rats.

Methods: Eight-week-old male Sprague-Dawley rats were fed an AIN-93M diet (control, Ang II, and Losartan (LOS; 20 mg/kg/BW) groups) or AIN-93M diet supplemented with 10% (w/w) freeze-dried BL, RB, or a combination of BL + RB (5% (w/w) each) for 7 weeks. Rats were implanted with subcutaneous osmotic minipumps delivering 0.9% saline (CON) or Ang II (270 ng/kg/BW/min; Ang II, LOS, BL, RB, BL + RB) at week 5. Blood pressure (BP) was measured using tail-cuff plethysmography weekly. Feces were collected every other week. Microbiota composition was analyzed through Illumina-based 16S rRNA gene sequencing. Data were analyzed using ANOVA or Kruskal-Wallis based on normality test results.

Results: Systolic BP at week 7 was lower in CON (p < 0.0001), LOS (p < 0.0001), RB (p = 0.0001), and BL + RB (p = 0.004) compared to Ang II group. Principal coordinate analysis of the Bray Curtis distance revealed a strong impact of berry supplementation on the microbiota community structure. More specifically, berry supplementation significantly increased microbiota’s richness, as revealed by computing of the Shannon alpha diversity index. Firmicutes (F)/Bacteroidetes (B) ratio was lower at week 4 in RB (p = 0.03) and BL + RB (p = 0.02) groups compared to Ang II. At week 7, only RB supplementation reduced F compared to Ang II (p = 0.01); however, there was a significant increase in B in RB (p = 0.03) and BL + RB (p = 0.007) groups.

Conclusions: We report that a diet rich in BL and RB protects against increases in systolic BP induced by Ang II and favorably modifies the gut microbiota in male rats. Further studies are warranted to confirm these findings in humans.

Funding Sources: The Agriculture and Food Research Initiative (grant no. 2019-67017-29257/project accession no. 1018642) from the USDA National Institute of Food and Agriculture.