Aerobic Exercise Training Partially Reverses Inward Hypertrophic Coronary Arteriole Remodeling in Type 2 Diabetic db/db Mice

The aim of this study was to determine whether aerobic exercise training improves impaired coronary arteriole remodeling in type 2 diabetic db/db mice. Eight wk old male mice were divided into: control sedentary (Db/db), diabetic sedentary (db/db), and diabetic trained (db/db‐TR). Exercise training (ET) was performed on a mouse treadmill for 5 days/wk, 60 min/day, at a speed of 9–10 m/min, 0% grade without electric stimulation for 8 wks. Coronary arterioles were mounted on a pressure myograph to measure wall thickness and diameters over a range of pressures (0–125 mmHg). Coronary arterioles isolated from db/db mice exhibited decreased luminal diameter (Db/db: 119 ± 6 μm vs. db/db: 102 ± 5 μm p < 0.05) with thicker microvascular walls (Db/db: 7.0 ± 0.2 μm vs. db/db: 9.1 ± 0.6 μm p < 0.01), which significantly increased the wall:lumen ratio (Db/db: 6.2 ± 0.4 vs. db/db: 8.8 ± 0.6, p < 0.01). Compared to db/db mice, coronary arterioles isolated from db/db‐ TR mice had similar internal diameter (109 ± 6 μm, p > 0.05) and wall thickness (7.5 ± 0.5 μm, p = 0.14), while wall:lumen ratio (6.8 ± 0.2 μm, p < 0.05) and growth index (db/db: 22.8 vs. db/db‐TR: 5.8, % of Db/db) were reduced. External diameters were not different among groups. These data suggest that aerobic exercise training can mitigate inward hypertrophic remodeling observed in coronary arterioles of type 2 diabetic mice. Support: NIH T32HL098039 to AJT; NIH HL056046 and NCH to PAL.