Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2899158 | Cardiovascular Pathology | 2010 | 10 Pages |
IntroductionDiabetes in human subjects is often associated with hypertension. The aim of this study was to examine the development of cardiac fibrosis following induction of type 1 diabetes in genetically hypertensive rats.MethodsDiabetes was induced by streptozotocin (STZ) injection in 8-week-old normotensive Wistar–Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs) for a duration of 16 or 24 weeks. Aged-matched, nondiabetic WKY and SHRs were used as controls. At termination of treatment, the rats were anaesthetized, hearts arrested in diastole and perfusion fixed. A comprehensive examination of cardiac fibrosis throughout the right and left ventricles was undertaken in picrosirius red-stained sections, using image analysis and by undertaking collagen type I and type III immunohistochemistry.ResultsInduction of diabetes in the SHRs led to a marked increase in the levels of interstitial fibrosis in the left ventricle plus septum (LV+S) at both 16 and 24 weeks duration (59% and 43% increase, respectively) and also in the right ventricle after 24 weeks duration of diabetes (35% increase compared to the nondiabetic SHR). Exacerbated perivascular fibrosis was also observed in the LV+S in the diabetic-hypertensive rats at the later time point. These effects of induction of diabetes were not observed in the normotensive strain.Conclusions/InterpretationOur findings clearly demonstrate elevations in cardiac fibrosis when type 1 diabetes is combined with hypertension. Our findings thus stress the importance of closely monitoring both blood pressure and glucose levels in type 1 diabetic patients in order to prevent myocardial collagen deposition.