Introduction:Low exercise capacity is a strong predictor of cardiovascular disease and overall mortality. Previously we have shown that rats artificially selected for low intrinsic exercise capacity (LCR) have reduced longevity and develop features consistent with metabolic syndrome (MetS) compared to high intrinsic exercise capacity rats (HCR). Current knowledge suggests that gut microbiota is an important contributor for host fitness. Thus, we hypothesized that transferring gut microbiota from LCR rats into inbred high capacity runner (HCR /Tol) rats would increase risk factors for MetS, including high blood pressure (BP), gain in body weight (BW), and altered resting energy metabolism. Methods:Gut microbiota was depleted in male HCR/ Tolrats (4 mo.) by an antibiotic cocktail given orally (50mg/kg of BW/day) for 5 days, followed by weekly fecal microbiota transfer (FMT) from male LCR or HCR rats (13 mo.) to generate HCR/ Tol-LCR FMT (n = 5) or HCR/ Tol-HCR FMT (n = 6) groups. BW was measured every 4 weeks. At week 11, whole body metabolism was measured by indirect calorimetry (Oxymax, Columbus Instruments). Respiratory Exchange Ratio (RER), Energy Expenditure (EE), glucose and fat oxidation were calculated from oxygen consumption and carbon dioxide release (VO 2 and VCO 2 ). At week 12, BP was measured by tail-cuff method (Kent Scientific) and treadmill exercise test was done at week 13. Results:Compared to HCR/ Tol-HCR FMT , HCR/ Tol-LCR FMT showed a significant gain in BW (7.2% vs 1.9%, P<0.05), elevated systolic BP (147 vs 120 mmHg, P<0.0001), diastolic BP (112 vs 91 mmHg, P<0.01), and mean BP (123 vs 100 mmHg, P<0.001). BP changes in HCR/ Tol-LCR FMT associated with 1) increased VO 2 (355 vs 320 ml/hr, P<0.05), 2) elevated VCO 2 (350 vs 298 ml/hr, P<0.01), 3) increased EE (1.8 vs 1.6 kcal/hr, P<0.01), 4) higher RER (0.96 vs 0.91, P<0.001), 5) higher glucose oxidation (1.36 vs 1.12 g/kg/hr, P<0.001) and 6) reduced fatty acid oxidation (0.09 vs 0.15 g/kg/hr, P<0.01) and a 23% lower exercise capacity. Conclusions:Gut microbiota from LCR rats strongly associated with poor health outcomes, notably elevated BP and impaired energy metabolism. These findings suggest that altered energy homeostasis by microbiota is mechanistically linked to host BP regulation within MetS.
- HYPERTENSION Journal
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