Autophagy as a mechanism for myolysis of cardiomyocytes in mitral regurgitation

Mien Cheng Chen*, Jen Ping Chang, Ya Hui Wang, Wen Hao Liu, Wan Chun Ho, Hsueh Wen Chang

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

26 Scopus citations

Abstract

Background Myolysis of atrial cardiomyocytes occurs in patients with severe mitral and tricuspid regurgitation. This morphological remodelling may involve autophagy. Methods This study comprised 20 patients (10 with long-standing persistent atrial fibrillation and 10 with sinus rhythm) with severe mitral and tricuspid regurgitation. Atrial appendageal tissues were obtained during surgery. The appearance of autophagosomes (LC3B) in myocytes can reflect autophagy induction. Complement 9 is used as a reliable marker of oncosis. Results In the fibrillating right atria, 68·4±18·9% of total myocytes showed moderate-to-severe myolysis, while 64·2±15·8% of total myocytes comprised these cells in right atrial myocardium with sinus rhythm. Immunohistochemical study revealed LC3B-positive myocytes in 8·0% of myocytes without myolysis, 11·9% of myocytes with mild myolysis and 49·4% of myocytes with moderate-to-severe myolysis in right atrial myocardium with sinus rhythm (P<0·0001). Similarly, in the fibrillating right atria, LC3B-positive myocytes were observed in 5·9% of myocytes without myolysis, 12·2% of myocytes with mild myolysis and 50·7% of myocytes with moderate-to-severe myolysis (P<0·0001). Moreover, in the fibrillating left atria, LC3B-positive myocytes were observed in 4·9% of myocytes without myolysis, 12·6% of myocytes with mild myolysis and 52·0% of myocytes with moderate-to-severe myolysis (P<0·0001). None of the atrial myocytes displayed intracellular deposition of complement 9. Conclusions Induction of autophagy, but not oncosis, occurs in most cases of atrial cardiomyocytes with severe mitral and tricuspid regurgitation, even those without atrial fibrillation, and is closely associated with the development of myolysis in this disease.

Original languageEnglish
Pages (from-to)299-307
Number of pages9
JournalEuropean Journal of Clinical Investigation
Volume41
Issue number3
DOIs
StatePublished - 03 2011

Keywords

  • Atrial fibrillation
  • Atrium
  • Autophagy
  • Mitral valve insufficiency
  • Myolysis

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