Medium-chain specific acyl-CoA dehydrogenase, mitochondrial precursor (EC 1.3.8.7) (MCAD) (Medium chain acyl-CoA dehydrogenase) (MCADH)
Left ventricular hypertrophy is a major cause of heart failure in aging population. This study is to determine whether an excess dietary fat is lipotoxic or lipoprotein to the hypertrophic aging heart. At 44-week-old, a normal chow (12% fat) was replaced a high-fat diet (HFD; 45% fat) for randomly selective spontaneously hypertensive rats (SHR HFD, n = 6) and Wistar-Kyoto rats (WKY HFD, n = 6, normotensive control). Others (SHR, n = 11; WKY, n = 10) were continuously fed with normal diets. After 27 weeks, electrocardiogram, echocardiography, and femoral arterial catheterization were performed before rats being sacrificed for molecular biology analyses. HFD aggravated cardiac atrial, ventricular dilation and hypertrophy in SHR (LV mass: SHR HFD 2026.0 ± 424.9 vs SHR 1449 ± 461.1 mg, unpaired t test P < 0.05). HFD caused significant atrial dilatation in both WKY (LA diameter, 5.38 ± 0.36 vs 4.11 ± 0.42 mm, P < 0.001) and SHR (6.13 ± 0.79 vs 4.69 ± 1.00, P < 0.01). Only in SHR, HFD induced significant left ventricular dilatation (LV diameter, 8.87 ± 1.25 vs 7.08 ± 1.00 mm, P < 0.01) and reduced ejection fraction (LVEF, 62.8 ± 11.6 vs 75.1 ± 9.2 mm, P < 0.05). The α-myosin heavy chain was significantly upregulated in atria and ventricles of HFD groups. HFD induced significant upregulation of PPARα, ACADM, and TNFα transcripts in atrial tissues (P < 0.05). Hypertensive heart disease in aging rats was aggravated by HFD with worse atrial, ventricular remodeling and associated with left ventricular systolic function impairment.
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