A Muraishi1, H Kai, K Adachi, H Nishi, T Imaizumi. 1. The Third Department of Internal Medicine, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka 830-0011, Japan.
Abstract
OBJECTIVE: To investigate changes in the alignment of the sarcomeric filaments in hypertrophic cardiomyopathy and the effects of cardiac beta myosin heavy chain (beta-MHC) mutation on the sarcomeric ultrastructure. DESIGN: A retrospective analysis. PATIENTS: Endomyocardial biopsy samples were examined by transmission electron microscopy in seven patients with hypertrophic cardiomyopathy and beta-MHC mutation, six with hypertrophic cardiomyopathy but without the mutation, and five controls (with chest pain syndromes). MAIN OUTCOME MEASURE: Alignment of the sarcomeric filaments and the distance between neighbouring thick myosin filaments. RESULTS: In controls, cross sections of the sarcomere at the A band showed a highly organised orthohexagonal array with 6 thin actin filaments surrounding one thick myosin filament, whereas in hypertrophic cardiomyopathy the alignment of the sarcomeric filaments was sparse and disrupted. In hypertrophic cardiomyopathy with a mutation, the distance between neighbouring thick myosin filaments was greater than in controls (mean (SD) 45.3 (4.7) v 38.5 (3.5) nm, p < 0.05), and the variance of the distance was greater than in controls (8.0 (0.7) v 4.8 (1.0) nm, p < 0.001) or in patients with hypertrophic cardiomyopathy without a mutation (6.7 (0.6) nm, p < 0.05). In the latter, the variance of the distance was also greater than in the controls (p < 0.01). A significant correlation was found between the grade of the myocyte hypertrophy and the variance of the distance (r = 0.654; p < 0.01). CONCLUSIONS: The alignment of the sarcomeric filaments is disrupted in hypertrophic cardiomyopathy, particularly when there is beta-MHC mutation.
OBJECTIVE: To investigate changes in the alignment of the sarcomeric filaments in hypertrophic cardiomyopathy and the effects of cardiac beta myosin heavy chain (beta-MHC) mutation on the sarcomeric ultrastructure. DESIGN: A retrospective analysis. PATIENTS: Endomyocardial biopsy samples were examined by transmission electron microscopy in seven patients with hypertrophic cardiomyopathy and beta-MHC mutation, six with hypertrophic cardiomyopathy but without the mutation, and five controls (with chest pain syndromes). MAIN OUTCOME MEASURE: Alignment of the sarcomeric filaments and the distance between neighbouring thick myosin filaments. RESULTS: In controls, cross sections of the sarcomere at the A band showed a highly organised orthohexagonal array with 6 thin actin filaments surrounding one thick myosin filament, whereas in hypertrophic cardiomyopathy the alignment of the sarcomeric filaments was sparse and disrupted. In hypertrophic cardiomyopathy with a mutation, the distance between neighbouring thick myosin filaments was greater than in controls (mean (SD) 45.3 (4.7) v 38.5 (3.5) nm, p < 0.05), and the variance of the distance was greater than in controls (8.0 (0.7) v 4.8 (1.0) nm, p < 0.001) or in patients with hypertrophic cardiomyopathy without a mutation (6.7 (0.6) nm, p < 0.05). In the latter, the variance of the distance was also greater than in the controls (p < 0.01). A significant correlation was found between the grade of the myocyte hypertrophy and the variance of the distance (r = 0.654; p < 0.01). CONCLUSIONS: The alignment of the sarcomeric filaments is disrupted in hypertrophic cardiomyopathy, particularly when there is beta-MHC mutation.
Authors: H Kai; A Muraishi; Y Sugiu; H Nishi; Y Seki; F Kuwahara; A Kimura; H Kato; T Imaizumi Journal: Circ Res Date: 1998-09-21 Impact factor: 17.367
Authors: L Thierfelder; H Watkins; C MacRae; R Lamas; W McKenna; H P Vosberg; J G Seidman; C E Seidman Journal: Cell Date: 1994-06-03 Impact factor: 41.582
Authors: H Nishi; A Kimura; H Harada; K Adachi; Y Koga; T Sasazuki; H Toshima Journal: Biochem Biophys Res Commun Date: 1994-04-15 Impact factor: 3.575