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Altered distribution of desmin filaments in hypertrophic cardiomyopathy: an immunohistochemical study
Insights
Altered desmin filament arrangement in hypertrophic cardiomyopathy (HCM) myofibers may impact heart contractility. This study reveals new patterns of desmin distribution in HCM cardiac muscle.
Area of Science:
- Cardiovascular Pathology
- Cell Biology
- Biochemistry
Background:
- Hypertrophic cardiomyopathy (HCM) involves myofiber hypertrophy and disarray.
- Intermediate filaments, like desmin, are crucial for cardiomyocyte structure.
- The distribution of intermediate filaments in HCM is not well understood.
Purpose of the Study:
- To investigate the arrangement of intermediate filaments, specifically desmin, vimentin, and keratins, in the disarrayed myofibers of hypertrophic cardiomyopathy (HCM) hearts.
- To compare intermediate filament distribution in HCM with control tissues from ischemic heart disease.
Main Methods:
- Immunohistochemical analysis of formalin-fixed cardiac tissue sections from 10 HCM patients and ischemic heart disease controls.
- Utilized antibodies against desmin, vimentin, and high/low molecular weight keratins.
- Examined desmin localization in Z bands, intercalated disks, and cytoplasmic regions.
Main Results:
- In ischemic controls, desmin localized to Z bands and intercalated disks.
- HCM hearts exhibited three desmin staining patterns: parallel along Z bands, focal loss at Z bands, and intense granular cytoplasmic staining, particularly in disarrayed myofibers.
- No vimentin or keratin staining was observed in cardiomyocytes of either HCM or control groups.
Conclusions:
- The altered arrangement of desmin filaments in hypertrophic cardiomyopathy (HCM) cardiac muscle fibers is a significant finding.
- These changes in desmin distribution may contribute to the altered contractility observed in HCM patients.
- Further research into desmin's role in HCM pathophysiology is warranted.
Abstract:
Hypertrophic cardiomyopathy (HCM) is characterized by myofiber hypertrophy and disarray. Intermediate filaments play an important role in maintaining of normal cell shape. Desmin filaments have been detected in adult cardiomyocytes, and vimentin and keratin filaments in cardiomyocytes during embryonic development. The pattern of arrangement of intermediate filaments in HCM has not been reported. We examined the distribution of intermediate filaments in formalin-fixed tissue sections of the disarrayed myofibers from 10 hearts with HCM using an immunohistochemical technique and antibodies to desmin, vimentin, and high and low molecular weight keratins. The controls consisted of subaortic tissue from surgically explanted hearts of patients with ischemic heart disease. In the ischemic hearts, desmin was detected in the Z bands and intercalated disks. In all HCM cases, three patterns of staining for desmin were noted: (a) individual myocytes showing a parallel arrangement along Z bands; (b) focal myofibers with decreased or complete loss of labeling of Z bands; and (c) individual myocytes with intense granular cytoplasmic staining especially in disarrayed myofibers. No staining for vimentin or keratins was noted in the cardiomyocytes from either the HCM or ischemic cases. The altered arrangement of desmin filaments in the disarrayed cardiac muscle fibers may play a role in the altered contractility that occurs in patients with HCM.