A negative correlation was observed between the left ventricular collagen III/I ratio and diastolic function (-dP/dt/MAP) (r = -0.91; P < 0.05) in rat models of exercise and hypertension.
Effect estimate: r = -0.91
p-value: p=< 0.05
Chronic hypertension, known to affect the collagen profile of the heart, and exercise result in impaired or improved heart function, respectively. Collagen types I alpha 1(I)2 and alpha 2(I) and III alpha 1(III)3 are the predominant interstitial collagens thought to influence cardiac function, and the ratio of type III to I (collagen III/I) is thought to be a significant factor in the altered relaxation observed in hypertrophy. The present study tested the hypothesis that the myocardial structure and function are different in chronically exercise-trained vs. hypertensive rat hearts. Male rats were either chronically exercised (XTr) or submitted to experimental hypertension by coarctation of the abdominal aorta (Hyp) for 10 wks. Heart rate, blood pressure, and maximal rate of fall of the left ventricular pressure (-dp/dt) were recorded during isoproterenol stimulation. Results showed that both Hyp and XTr had higher heart weight and left ventricular weight-to-body weight ratios (P < 0.05). Mean arterial pressure (MAP) was higher in Hyp and lower in XTr (P < 0.05), whereas (-dP/dt)/MAP was diminished in Hyp but enhanced in XTr. Left ventricular collagen was higher in Hyp than XTr, whereas collagen III/I was reduced in Hyp compared with XTr (P < 0.05). Scanning and transmission electron microscopy also supported an accumulation of left ventricular collagen in Hyp compared with XTr. A negative correlation was observed between collagen III/I and (-dP/dt)/ MAP (r = -0.91; P < 0.05). These results suggest an important relationship between adaptations in left ventricular collagen and the changes in diastolic function observed in both chronic hypertension and exercise cardiac stress.
Burgess et al. (Mon,) conducted a other in Chronic hypertension and exercise cardiac stress. Chronic exercise or experimental hypertension vs. Each other was evaluated on Correlation between collagen III/I and (-dP/dt)/MAP (r = -0.91, p=< 0.05). A negative correlation was observed between the left ventricular collagen III/I ratio and diastolic function (-dP/dt/MAP) (r = -0.91; P < 0.05) in rat models of exercise and hypertension.