The Relationship between Extracellular Matrix Change and Left Ventricular Systolic and Diastolic Function in Cardiomyopathic Hamsters

The time course of the development of cardiomyopathic hamster has been examined, but the relationship between the extracellular matrix change, especially, hydroxyproline content and the left ventricular (LV) systolic and diastolic function has been poorly understood. Therefore this study was designed to clarify the time course of the change in the extracellular matrix and the hemodynamic parameters in cardiomyopathic hamsters. Cardiomyopachic hamsters (UM-X7.1) were examined at the age of 12,16,20,24 and 28 weeks. The hamsters were anesthetized and ventilated, and left ventricular echocardiograhic assessment was performed with 7.5MHz echo probe. Left ventricular pressure was measured through a neede punctured through the LV apex. Left ventricular end-iastolic (LVDd) and end-systolic dimensions (LVDs), and fractional shortening (FS) were calculated. LV peak systolic pressure (LVPSP), LV end-diastolic pressure(LVEDP) and heart rate (HR) , (+)dP/dt and (-)dP/dt of LVP and the time constant of LVP decay (T) were obtained. LV hydoxyproline content (HYP) was measured by the Kivirikko method. HYP increased in accordance with age. HYP positively correlated with LVDd and T, and inversely correlated with FS, but no significant correlation was observed with (+)dP/dt. In UM-X7.1, the systolic function and diastilic function both correlated with the hydroxyproline content in the left ventricule, and the hydroxyproline content increased in accordance with the progression of the myopathic disease.

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