Time Restricted Feeding Reduces Vascular Damage and Oxidative Stress in Male Mice on a Chronic High Fat Diet

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Irregular timing of food intake is known to influence risk for cardiometabolic disease. Studies in humans and animals demonstrate that a chronic high fat diet (HFD) leads to endothelial dysfunction and cardiovascular disease. We hypothesized that restricting food availability to the active period with a HFD leads to reduced vascular damage, increased nitric oxide synthase (NOS3) activation, and reduced oxidative stress. Mice (male 8‐week old, C57BL/6J) were given a normal diet (ND; 10% fat) or HFD (45% fat) for 20 weeks ad libitum. Time restricted feeding (TRF; food availability only during the active phase between ZT12 to ZT0 or 7 PM to 7 AM) was enforced in half of the HFD mice during the final 2 weeks of feeding. At the end of the study, aortae and plasma were collected at ZT5 and ZT17 in the middle of the inactive and active periods, respectively. 24 hour food intake was similar between ad lib and TRF mice. Aortic wall thickness was significantly increased in mice on HFD compared to ND (HFD: 76±5.1 μm; ND: 59±4.6 μm; n=6, p=0.03). Interestingly, aortic fibrosis was reduced by TRF in HFD mice (HFD: 18±2.3%; HFD+TRF: 11±1.9%; n=6, p=0.04). To assess NOS3 activation, Western blotting was used to measure pNOS3(S1177) and NOS3 abundance in aortae. At ZT5 pNOS3(S1177) abundance was not affected by TRF in HFD mice (HFD: 0.5±0.3 rdu, HFD+TRF: 0.7±0.1 rdu, n=4). TRF significantly increased pNOS3(S1177) abundance in HFD mice at ZT17 (HFD: 0.5±0.2 rdu, HFD+TRF: 2.1±0.6 rdu, n=4, p=0.06). Total NOS3 expression was unaffected by TRF at both time points. During the inactive period, endothelial‐dependent relaxation to acetylcholine was significantly impaired in HFD mice and improved by TRF (ND: 93±1.4%; HFD: 57±14%; HFD+TRF: 79±4.0%, n=5–11, ND vs HFD: p=0.01). Endothelial function was not different between groups in the active period. Endothelial‐independent relaxation was similar in all groups in both inactive and active periods. Plasma nitrite, a metabolite of NO, at ZT5 was unchanged between all groups. At ZT17 plasma nitrite was significantly decreased in HFD mice compared to ND mice and unaffected by TRF (HFD: 0.6±0.06 μM; HFD+TRF: 0.7±0.03 μM; ND: 1.1±0.2 μM; n=10–11, p=0.03). 8‐isoprostane, an indirect measure of oxidative stress, was significantly reduced by TRF in HFD mice at ZT5 (HFD: 159±31 ng/mL; HFD+TRF: 60±12 ng/mL, n=4–6, p=0.01), but not different between groups at ZT17. In conclusion, these results demonstrate that restricting timing of food intake improves vascular damage and decreases oxidative stress following diet‐induced obesity in a time‐dependent manner.Support or Funding InformationSupported by T32 DK007545, an AHA Postdoctoral Fellowship (18POST34070051) to PP, an AHA Predoctoral Fellowship (18PRE33990345) to DZ, P01 HL069999 to JSP and DMP, and P01 HL136267 to JSP, EWI, and DMP.