Effects of Grape Supplementation on Age‐Related Vascular Changes in Mice

Abstract

Chronological aging leads to changes in several physiological process, including vascular function. All blood vessels, including conduit and resistance arteries, develop age‐related impairment in vascular relaxation that is possibly due to endothelium dysfunction and less bioavailability of endothelium‐derived factors such as nitric oxide (NO). We studied vascular responses using aorta from aged female mice that were maintained on four different diets from weaning until 30 months: normal chow (NC), high‐fat diet (HFD), NC + grape supplement (NCG) and HFD + grape supplement (HFDG). Ex‐vivo experiments with aorta using an organ bath showed that HFD had the lowest relaxation when exposed to 10 μM acetylcholine (27.12 ± 7.53%), followed by NC (45.45 ± 5.61%; p = 0.098 NC vs. HFD). The grape supplemented group NCG had higher relaxation than nonsupplement NC (70 ± 24.25%; p >0.05). HFDG also had improved acetylcholine‐mediated relaxation (60 ± 12.8%; p = 0.0642 HFD vs. HFDG). L‐NAME (eNOS inhibitor; 10−4 M) changed the acetylcholine response to contraction in all groups, with the HFD having the highest contraction (80.45 ± 12.23% vs. 35.87 ± 9.43% in HFDG; p <0.05) compared to other groups which had similar contraction. However, indomethacin [prostaglandin (PG) inhibitor] produced the highest contraction in the HFDG group. These data suggest that grape supplementation may preserve PG‐mediated relaxation in vascular tissue in HFDG mice with NO and PG both contributing to relaxation, while in nonsupplemented HFD mice, the vasorelaxation occurred primarily through nitric oxide that was inhibited by the use of L‐NAME. (Supported in part by the California Table Grape Commission)Support or Funding InformationCalifornia Table Grape Commission (JP)