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Streptozotocin-induced hyperglycemia exacerbates left ventricular remodeling and failure after experimental
Tetsuya Shiomi1, Hiroyuki Tsutsui, Masaki Ikeuchi
1Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, 812-8582 Fukuoka, Japan.
Objectives:
The aim of the present study was to determine whether streptozotocin (STZ)-induced hyperglycemia exacerbates progressive left ventricular (LV) dilation and dysfunction after myocardial infarction (MI).
Background:
Diabetes mellitus (DM) adversely affects the outcomes in patients with MI. However, it is unknown whether DM can directly affect the development of post-MI LV remodeling and failure.
Methods:
Male mice were injected intraperitoneally with STZ (200 mg/kg; DM group) or vehicle only. At two weeks, MI was created in the STZ-injected (DM+MI group) or vehicle-injected mice (MI group) by left coronary artery ligation, and they were followed up for another four weeks.
Results:
Survival during six weeks was significantly lower in the DM+MI versus MI group (25% vs. 71%; p < 0.01), despite a similar infarct size (60 +/- 2% vs. 61 +/- 2%; p = NS). Echocardiography after two weeks of ligation showed LV dilation and dysfunction with MI, both of which were exaggerated in the DM+MI group. Likewise, LV end-diastolic pressure and lung weight were increased in mice with MI, and this increase was enhanced in the DM+MI group. The myocyte cross-sectional area in the non-infarcted LV increased to a similar degree in the DM+MI and MI groups, whereas the collagen volume fraction was greater in the DM+MI group. Deoxyribonucleic acid laddering was greater in the DM+MI group.
Conclusions:
Hyperglycemia decreased survival and exaggerated LV remodeling and failure after MI by increasing interstitial fibrosis and myocyte apoptosis. Diabetes mellitus could be a risk factor for heart failure, independent of coronary artery lesions.