(P26-017-25) Impact of Daily Berry Supplementation on Blood Pressure and Intestinal Health in Angiotensin II-Treated Rats

Objectives: High blood pressure (BP) is associated with intestinal barrier dysfunction. Widely consumed fruits such as blackberries (BL), blueberries (BB), raspberries (RB), and strawberries (SB) are known for their antioxidant effects. Thus, the objective of this study was to evaluate the impact of a mixed-berry diet on cardiovascular and intestinal health in angiotensin (Ang) II-treated rats.

Methods: Male Sprague-Dawley rats were fed an AIN-93M diet alone (control (CON), Ang, and Losartan (LOS; 20 mg/kg/BW) groups) or supplemented with 10% w/w freeze-dried berries (equal parts BL, RB, BB, and SB; Berry) for 8 weeks. Subcutaneous osmotic minipumps delivering 0.9% saline (CON) or Ang II (270 ng/kg/BW/min; Ang, LOS, and Berry) were implanted at week 4. BP, serum nitric oxide (NO), and intestinal permeability (IP) were assessed starting at week 4. Protein markers of inflammation and oxidative stress in the distal colon were assessed by Western Blot. Trichrome staining was performed in the proximal colon.

Results: Berry supplementation significantly attenuated increases in systolic BP compared to Ang II alone (162 ± 15 vs 202 ± 11 mmHg, p < 0.0001) after 8 weeks. Serum NO was higher in Ang (0.21 ± 0.1 μM, p = 0.03) and Berry (0.52 ± 0.3 μM, p = 0.01) at week 8 compared to CON (0.05 ± 0.03 μM); however, Berry was higher compared to all groups at week 5. IP was higher in Ang at week 8, albeit not significantly. Phosphorylation of p38, a redox-sensitive mitogen activated protein kinase, was increased by Ang compared to CON (p = 0.01). LOS prevented this increase (p = 0.03) while Berry did not (p = 0.7). Ang (p = 0.08) and Berry (p = 0.004) had higher expression of heme oxygenase 1, an antioxidant enzyme, compared to LOS with non-significant increase compared to CON (p = 0.7 and p = 0.1, respectively). The antioxidant, glutathione peroxidase 1, was decreased in LOS (p = 0.04) and Ang (p = 0.1) compared to CON, but not Berry (p = 0.4). Lastly, an increase in fibrosis was observed in Ang compared to the other groups.

Conclusions: Our data support a potential role for mixed berries to mitigate the onset of hypertension and blunt the associated alterations to the intestinal barrier by increasing antioxidant enzyme expression. Further investigation is warranted.

Funding Sources: The Agriculture and Food Research from the USDA National Institute of Food and Agriculture.