β-carotene supplementation results in adverse ventricular remodeling after acute myocardial infarction

Objective: We studied the effects of beta-carotene (BC) on ventricular remodeling after myocardial infarction. Methods: Myocardial infarction was induced in Wistar rats that were then treated with a BC diet (500 mg/kg of diet per day; MI-BC; n = 27) or a regular diet (MI; n = 27). Hearts were analyzed in vivo and in vitro after 6 mo. Results: BC caused decreased left ventricular wall thickness (MI = 1.49 +/- 0.3 mm, MI-BC = 1.23 +/- 0.2 mm, P = 0.027) and increased diastolic (MI = 0.83 +/- 0.15 cm(2), MI-BC = 0.98 +/- 0.14 cm(2), P = 0.020) and systolic (MI = 0.56 +/- 0.12 cm(2), MI-BC = 0.75 +/- 0.13 cm(2), p = 0.002) left ventricular chamber areas. With respect to systolic function, the BC group presented less change in fractional area than did controls (MI = 32.35 +/- 6.67, MI-BC = 23.77 +/- 6.06, P = 0.004). There was no difference in transmitral diastolic flow velocities between groups. In vitro results showed decreased maximal isovolumetric systolic pressure (MI = 125.5 +/- 24.1 mmHg, MI-BC = 95.2 +/- 28.4 mmHg, P = 0.019) and increased interstitial myocardial collagen concentration (MI = 3.3 +/- 1.2%, MI-BC = 5.8 +/- 1.7%, P = 0.004) in BC-treated animals. Infarct sizes were similar between groups (MI = 45.0 +/- 6.6%, MI-BC = 48.0 +/- 5.8%, P = 0.246). Conclusion: Taken together, these data suggest that BC has adverse effects on ventricular remodeling after myocardial infarction. (c) 2006 Elsevier Inc. All rights reserved.