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Saito T, Sato NS, Mozawa K, Adachi A, Sasaki Y, Nakamura K, Oka E, Otsuka T, Kodani E, Asai K, Mizuno K, Shimizu W, Gottlieb RA. Myocardial ultrastructure can augment genetic testing for sporadic dilated cardiomyopathy with initial heart failure. ESC Heart Fail 2021; 8:5178-5191. [PMID: 34486814 PMCID: PMC8712817 DOI: 10.1002/ehf2.13596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 07/06/2021] [Accepted: 08/23/2021] [Indexed: 11/30/2022] Open
Abstract
Aims The aim of the present study was to consider whether the ultrastructural features of cardiomyocytes in dilated cardiomyopathy can be used to guide genetic testing. Methods and results Endomyocardial biopsy and whole‐exome sequencing were performed in 32 consecutive sporadic dilated cardiomyopathy patients [51.0 (40.0–64.0) years, 75% men] in initial phases of decompensated heart failure. The predicted pathogenicity of ultrarare (minor allele frequency ≤0.0005), non‐synonymous variants was determined using the American College of Medical Genetics guidelines. Focusing on 75 cardiomyopathy‐susceptibility and 41 arrhythmia‐susceptibility genes, we identified 404 gene variants, of which 15 were considered pathogenic or likely pathogenic in 14 patients (44% of 32). There were five sarcomeric gene variants (29% of 17 variants) found in five patients (16% of 32), involving a variant of MYBPC3 and four variants of TTN. A patient with an MYBPC3 variant showed disorganized sarcomeres, three patients with TTN variants located in the region encoding the A‐band domain showed sparse sarcomeres, and a patient with a TTN variant in encoding the I‐band domain showed disrupted sarcomeres. The distribution of diffuse myofilament lysis depended on the causal genes; three patients with the same TMEM43 variant had diffuse myofilament lysis near nuclei (P = 0.011), while two patients with different DSP variants had lysis in the peripheral areas of cardiomyocytes (P = 0.033). Conclusions Derangement patterns of myofilament and subcellular distribution of myofilament lysis might implicate causal genes. Large‐scale studies are required to confirm whether these ultrastructural findings are related to the causative genes.
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Affiliation(s)
- Tsunenori Saito
- Smidt Heart Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA.,Department of Cardiovascular Medicine, Nippon Medical School Graduate School, Tokyo, Japan
| | - Naoko Saito Sato
- Department of Neurology, Japanese Red Cross Medical Center, Tokyo, Japan
| | - Kosuke Mozawa
- Department of Cardiovascular Medicine, Nippon Medical School Graduate School, Tokyo, Japan
| | - Akiko Adachi
- Division of Morphological and Biomolecular Research, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Yoshihiro Sasaki
- Division of Morphological and Biomolecular Research, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Kotoka Nakamura
- Smidt Heart Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Eiichiro Oka
- Department of Cardiovascular Medicine, Nippon Medical School Graduate School, Tokyo, Japan
| | - Toshiaki Otsuka
- Department of Hygiene and Public Health, Nippon Medical School Graduate School, Tokyo, Japan
| | - Eitaro Kodani
- Department of Internal Medicine and Cardiology, Nippon Medical School Tama Nagayama Hospital, Tokyo, Japan
| | - Kuniya Asai
- Intensive Care Unit, Nippon Medical School Chiba Hokusoh Hospital, Chiba, Japan
| | - Kyoichi Mizuno
- Department of Cardiovascular Medicine, Nippon Medical School Graduate School, Tokyo, Japan
| | - Wataru Shimizu
- Department of Cardiovascular Medicine, Nippon Medical School Graduate School, Tokyo, Japan
| | - Roberta A Gottlieb
- Smidt Heart Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
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Takemura G, Onoue K, Nakano T, Nakamura T, Sakaguchi Y, Tsujimoto A, Miyazaki N, Watanabe T, Kanamori H, Okada H, Kawasaki M, Fujiwara T, Fujiwara H, Saito Y. Possible mechanism for disposal of degenerative cardiomyocytes in human failing hearts: phagocytosis by a neighbour. ESC Heart Fail 2018; 6:208-216. [PMID: 30478956 PMCID: PMC6351884 DOI: 10.1002/ehf2.12383] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 10/23/2018] [Indexed: 11/20/2022] Open
Abstract
The index case was a 51‐year‐old woman suffering from doxorubicin cardiomyopathy. In her endomyocardial biopsy specimen, we observed under electron microscopy six scenes in which degenerative cardiomyocytes were engulfed by neighbouring cardiomyocytes. The enclosed cardiomyocytes appeared more degenerative than the enclosing ones in every pair: the myofibrils were more severely damaged. At more degenerative stages, some desmosomes of the intercalated discs on the enclosed cardiomyocyte had disappeared. The membranes between the cardiomyocytes were occasionally disrupted, and there appeared to be sharing of cellular contents between the cells. One pair of such a phagocytosis‐like figure was observed in one case with 5‐fluorouracil cardiomyopathy (a 68‐year‐old man) among eight other chemotherapy‐induced cardiomyopathies but none among 30 non‐drug‐induced dilated cardiomyopathies. The findings suggest a mechanism for disposal of degenerative cardiomyocytes in human failing hearts: phagocytosis by a neighbour, although alternative interpretations remain (e.g. giant autophagic vacuoles or two cardiomyocytes with degenerative intercalated discs).
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Affiliation(s)
- Genzou Takemura
- Department of Internal Medicine, Asahi University School of Dentistry, Mizuho, Japan
| | - Kenji Onoue
- Department of Cardiovascular Medicine, Nara Medical University, Kashihara, Japan
| | - Tomoya Nakano
- Department of Cardiovascular Medicine, Nara Medical University, Kashihara, Japan
| | - Takuya Nakamura
- Department of Cardiovascular Medicine, Nara Medical University, Kashihara, Japan
| | - Yasuhiro Sakaguchi
- Department of Cardiovascular Medicine, Nara Medical University, Kashihara, Japan
| | - Akiko Tsujimoto
- Department of Cardiology, Gifu University School of Medicine, Gifu, Japan
| | - Nagisa Miyazaki
- Department of Internal Medicine, Asahi University School of Dentistry, Mizuho, Japan
| | - Takatomo Watanabe
- Department of Cardiology, Gifu University School of Medicine, Gifu, Japan
| | - Hiromitsu Kanamori
- Department of Cardiology, Gifu University School of Medicine, Gifu, Japan
| | - Hideshi Okada
- Department of Emergency and Disaster Medicine, Gifu University School of Medicine, Gifu, Japan
| | - Masanori Kawasaki
- Department of Cardiology, Gifu University School of Medicine, Gifu, Japan
| | - Takako Fujiwara
- Hyogo Prefectural Amagasaki General Medical Center, Amagasaki, Japan
| | | | - Yoshihiko Saito
- Department of Cardiovascular Medicine, Nara Medical University, Kashihara, Japan
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