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Changes in extracellular matrix components in cardiomyopathic Syrian hamster, BIO 14.6
1First Department of Internal Medicine, Okayama University Medical School, Japan.
Insights
In cardiomyopathic hamsters, extracellular matrix components like fibronectin and collagen increased with disease progression. These changes indicate continuous fibrotic development throughout all stages of cardiomyopathy.
Area of Science:
- Cardiovascular Biology
- Extracellular Matrix Research
- Animal Models of Disease
Background:
- Cardiomyopathy involves complex changes in the heart's extracellular matrix.
- Understanding these matrix alterations is crucial for disease progression insights.
Purpose of the Study:
- To investigate the distribution of key extracellular matrix components during the progression of cardiomyopathy in Syrian hamsters (BIO 14.6).
- To determine the role of fibronectin, laminin, and collagen types I, III, and IV in fibrotic changes associated with this model.
Main Methods:
- Immunohistochemical staining using the avidin-biotin-peroxidase complex method.
- Analysis of heart tissues from four distinct stages of BIO 14.6 cardiomyopathy.
- Assessment of fibronectin, laminin, type IV collagen, and type I and III collagens distribution.
Main Results:
- Peri- and endomysial fibrosis significantly increased with disease progression.
- Replacement and meshwork fibrotic lesions were evident from the second stage onwards.
- All examined extracellular matrix components were present in fibrotic lesions, playing a significant role.
- Increased fibronectin distribution was observed early in the necrotic stage, with further increases as the disease advanced.
- Laminin and type IV collagen were found beyond the myocyte membrane in fibrotic areas.
- Type III collagen distribution correlated with type I collagen in fibrotic lesions.
Conclusions:
- Extracellular matrix components are integral to the fibrotic process in this cardiomyopathy model.
- No primary deficit of these matrix components was identified.
- Continuous increases in fibronectin, laminin, and type III collagen suggest ongoing fibrotic changes throughout cardiomyopathy progression.
Abstract:
We examined changes in the distribution of extracellular matrix components in the myocardium of cardiomyopathic Syrian hamsters (BIO 14.6). Fibronectin, laminin, and type IV collagen, and type I and III collagens were immunohistochemically stained by the avidin-biotin-peroxidase complex method, using a polyclonal antibody for each component. Hearts obtained from 4 stages of BIO 14.6 cardiomyopathy were examined. Peri- and endomysial fibrosis increased as the disease progressed. Replacement and meshwork (perimysial fibrosis penetrating the intercellular space) fibrotic lesions appeared beginning in the 2nd stage, ie, the fibrotic and healing stage. All of the components examined, ie, fibronectin, laminin and type IV collagen, and type I and III collagens, were present in various fibrotic lesions and played a significant role in fibrotic changes throughout all of the stages of the disease. No primary deficit of any of these components was seen. An increased distribution of fibronectin was observed in both the enlarged peri-and endomysial spaces beginning in the initial stage, ie, the necrotic stage, when myocyte hypertrophy was inconspicuous, and distribution throughout the myocardium increased further as the disease progressed. Laminin and type IV collagen in the fibrotic lesions were not restricted to the myocyte membrane. Type III collagen was distributed in replacement and meshwork fibrotic lesions, and the extent of its distribution increased in proportion to that of type I collagen. The continuous increases in the distribution of fibronectin, laminin and type III collagen indicate that fibrotic changes occurred continuously in this model.(ABSTRACT TRUNCATED AT 250 WORDS)