Hypertensive cardiomyopathy. Myocyte nuclei hyperplasia in the mammalian rat heart.
To determine whether long-term hypertension leads to hyperplasia of myocyte nuclei in the heart, a phenomenon suspected to occur in humans, renal hypertension was produced in rats and the animals were killed 8 mo later. Arterial blood pressure remained elevated for approximately 5 mo, but decreased progressively in the last 3 mo so that at 8 mo this parameter was practically identical to that found in controls. Moreover, left ventricular end diastolic pressure was markedly increased in experimental animals in association with a substantial decrease in left ventricular dP/dt. The alteration of these physiological measurements was indicative of severe ventricular dysfunction. Quantitative analysis of the transmural distribution of myocyte nuclei in the left ventricle showed 36 and 23% increases in myocyte nuclei concentration in the epimyocardium and endomyocardium, respectively. These changes in nuclei were accompanied by 25 and 16% reductions in myocyte cell volume per nucleus in the outer and inner layers of the wall. In conclusion, long-term hypertension leads to impairment of ventricular function and proliferation of nuclei in myocytes.
Anversa
P
P
Department of Pathology, New York Medical College, Valhalla 10595.
Palackal
T
T
Sonnenblick
E H
EH
Olivetti
G
G
Capasso
J M
JM
D000818:Animals; D006332:Cardiomegaly / Q000209:etiology; D009202:Cardiomyopathies / Q000209:etiology / Q000473:pathology*; D002467:Cell Nucleus / Q000473:pathology*; D006965:Hyperplasia; D006977:Hypertension, Renal / Q000150:complications*; D008297:Male; D009206:Myocardium / Q000473:pathology*; D051381:Rats; D011916:Rats, Inbred F344