Increased cardiomyocyte apoptosis during the transition to heart failure in the spontaneously hypertensive rat

Zhihe Li, Oscar H.L. Bing, Xilin Long, Kathleen G. Robinson, Edward G. Lakatta

Research output: Contribution to journalArticle

Abstract

The transition from compensated hypertrophy to failure in spontaneously hypertensive rats (SHR) of advanced age is associated with a marked increase in collagen, a reduction in myocyte mass, and a reduction in maximum Ca2+- activated myofibrillar force. We hypothesized that the reduction in myocyte mass and associated functional loss may be due to increased cell death by apoptosis. To test this hypothesis, we studied hearts from failing (SHR-F) and nonfailing SHR (SHR-NF) and age-matched Wistar-Kyoto rats (WKY). In addition, hearts from SHR-F that had been treated with an angiotensin- converting enzyme inhibitor (captopril) for an average of 27 days were also studied. Apoptotic cells were quantified in cross sections of myocardium by the terminal deoxynucleotidyltransferase-mediated 2'-deoxyuridine 5'- triphosphate nick end labeling technique. To identify the type of the cells undergoing apoptosis, sections were also stained for α-sarcomeric actin. Apoptotic cells were significantly increased in the SHR-F (38.92 ± 12.79 vs. 8.05 ± 3.98 cells/100,000 nuclei in SHR-NF; P < 0.05 and vs. 2.21 ± 1.4 cells/100,000 nuclei in WKY; P < 0.01). Captopril treatment of SHR-F reduced the number of apoptotic cells to the level in SHR-NF (9.17 ± 1.53 cells/100,000 nuclei; P < 0.01 vs. SHR-F). Most apoptotic cells were of cardiac myocyte origin. There was no significant difference in Bcl-2 protein expressed by hearts among the three groups. WAF-1 mRNA levels were increased in both SHR groups vs. WKY; in SHR-F, the density of WAF-1 mRNA was higher than in SHR-NF. Thus increased numbers of apoptotic cells are present in failing SHR hearts, suggesting that apoptosis might be a mechanism involved in the reduction of myocyte mass that accompanies the transition from stable compensation to heart failure in this model. Administration of the angiotensin-converting enzyme inhibitor captopril, which ameliorates heart failure in this model, is associated with a reduction in the exaggerated apoptosis that accompanies heart failure.

Original languageEnglish (US)
Pages (from-to)H2313-H2319
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume272
Issue number5 41-5
StatePublished - Jun 17 1997
Externally publishedYes

Keywords

  • DNA fragmentation
  • aging
  • terminal deoxynucleotidyltransferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Fingerprint Dive into the research topics of 'Increased cardiomyocyte apoptosis during the transition to heart failure in the spontaneously hypertensive rat'. Together they form a unique fingerprint.

  • Cite this