Myocardial hypertrophy of normotensive Wistar-Kyoto rats

AIELLO EA, VILLA-ABRILLE MC, ESCUDERO EM, PORTIANSKY EL, PEREZ NG, CAMILION DE HURTADO MC, CINGOLANI HE.

AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY

AMER PHYSIOLOGICAL SOC

Año: 2004 vol. 286 p. 1229 - 1235

0363-6135

Aiello, Ernesto A., Marý´a C. Villa-Abrille, Eduardo M. Escudero, Enrique L. Portiansky, Néstor G. Pérez, María C. Camilión de Hurtado, and Horacio E. Cingolani. Myocardial hypertrophy of normotensive Wistar-Kyoto rats. Am J Physiol Heart Circ Physiol 286: H1229?H1235, 2004. First published November 20, 2003; 10.1152/ajpheart.00779.2003.?In our studies with spontaneously hypertensive (SHR), Wistar-Kyoto (WKY), and Wistar rats, we observed normotensive WKY rats with cardiac hypertrophy determined by a greater left ventricular (LV) mass (LVM)-to-body weight (BW) ratio (LVM/BW) than that of normotensive Wistar rats. Thus we compared the following parameters in SHR, WKY, and Wistar rats: LVM/BW, cell capacitance as index of total surface area of the myocytes, length, width, and cross-sectional area of cardiac myocytes, LV collagen volume fraction, and myocardial stiffness. The LVM/BW of WKY (2.41  0.03 mg/g, n [1] 41) was intermediate between SHR (2.82  0.04 mg/g, n [1] 47) and Wistar rats (1.98  0.04 mg/g, n [1] 28). A positive correlation between blood pressure and LVM was found in SHR, whereas no such relationship was observed in WKY or Wistar rats. Cell capacitance and cross-sectional area were not significantly different in SHR and WKY rats; these values were significantly higher than those of Wistar rats. The cell length was smaller but the width was similar in WKY compared with SHR. Papillary muscles isolated from the LV of WKY and SHR were stiffer than those from Wistar rats. Consistently, a greater level of myocardial fibrosis was detected in WKY and SHR compared with Wistar rats. These findings demonstrate blood pressure-independent cardiac hypertrophy in normotensive WKY rats.