Expression of spliceosome assembly factor SC-35 in TUNEL-positive atrial cardiomyocytes in mitral and tricuspid regurgitation: Viability of atrial cardiomyocytes

Mien Cheng Chen*, Jen Ping Chang, Wan Chun Ho, Wen Hao Liu, Chien Jen Chen, Cheng Hsu Yang, Yung Lung Chen, Tzu Hsien Tsai

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

4 Scopus citations

Abstract

Background: Most of the atrial cardiomyocytes with positive terminal deoxynucleotidyl transferase (TdT)-mediated dUTP in situ nick end-labelling (TUNEL) reaction are not apoptotic in patients with mitral and tricuspid valve diseases. The TUNEL-positive myocytes with expression of spliceosome assembly factor SC-35, an indicator of increased RNA synthesis, should be living cardiomyocytes. Methods: This study analyzed twenty-three patients with significant mitral and tricuspid regurgitation. Fifteen patients had persistent atrial fibrillation, and eight had sinus rhythm. Atrial appendageal tissues were obtained during surgery. Immunohistochemical study was performed. Results: Immunohistochemical study of fibrillating right atrial myocardium demonstrated that 44.8 ± 24.6% of myocytes had TUNEL-positive nuclei whereas 39.4 ± 21.4% of myocytes had TUNEL-positive nuclei in sinus right atrial myocardium (p = 0.682). However, most (81.6%) nuclei of TUNEL-positive myocytes in the fibrillating right atria also expressed proliferating cell nuclear antigen (PCNA), an indicator of DNA replication and repair, and most nuclei (91.8%) of TUNEL-positive myocytes also expressed SC-35. In fibrillating left atria, most (88.1%) nuclei of TUNEL-positive myocytes also expressed SC-35. Similarly, in sinus right atrial myocardium, most (78.0%) nuclei of TUNEL-positive myocytes expressed PCNA, and most (91.4%) nuclei of TUNEL-positive myocytes also expressed SC-35, but none expressed Ki-67, a replication-associated antigen. Additionally, the percentage of TUNEL-positive myocytes in the right atria significantly and positively correlated with the percentage of PCNA-positive myocytes (r = 0.826, p < 0.001) and SC-35 positive myocytes (r = 0.713, p < 0.001). Conclusions: Most TUNEL-positive atrial cardiomyocytes in patients with mitral and tricuspid regurgitation are living cardiomyocytes.

Original languageEnglish
Pages (from-to)323-327
Number of pages5
JournalInternational Journal of Cardiology
Volume151
Issue number3
DOIs
StatePublished - 15 09 2011

Keywords

  • Apoptosis
  • Atrial fibrillation
  • Cardiac muscle cells
  • Heart atrium
  • Mitral valve insufficiency

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