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[Expression of the heat shock protein 70 in inflammatory myopathies]
Abstract:
Heat shock protein 70 (HSP 70) expression was immunohistochemically observed in diseased muscle fibers of 35 patients with dermatomyositis (DM) and 7 with polymyositis (PM). In DM, HSP 70 was localized in the sarcoplasm of type 1 fibers adjacent to the small vessels showing deposits of complement components in 13 patients and in the atrophic fibers at perifascicular regions in 7. HSP 70 was also expressed more preferentially in the small vessels rather than in the sarcoplasm in 13 DM patients. In PM, the expression of HSP 70 was blurred in all fibers including non-necrotic fibers invaded by T cells. In conclusion, HSP 70 is likely more frequently to be expressed in the sarcoplasm of DM than PM due to probable ischemic insults.
Insights
Heat shock protein 70 (HSP 70) is more commonly found in muscle fibers of dermatomyositis (DM) patients than polymyositis (PM) patients. This suggests HSP 70 may indicate ischemic damage in DM.
Area of Science:
- Immunology
- Neurology
- Pathology
Context:
- Dermatomyositis (DM) and polymyositis (PM) are inflammatory myopathies.
- Heat shock protein 70 (HSP 70) is a cellular stress marker.
- Understanding HSP 70 expression can elucidate disease mechanisms.
Purpose:
- To investigate and compare the expression patterns of HSP 70 in muscle biopsies from patients with DM and PM.
- To correlate HSP 70 localization with specific pathological features in these myopathies.
Summary:
- HSP 70 was immunohistochemically assessed in 35 DM and 7 PM patients.
- In DM, HSP 70 localized to sarcoplasm of type 1 fibers, atrophic fibers, and small vessels, particularly those with complement deposits.
- In PM, HSP 70 expression was diffuse across muscle fibers, including those infiltrated by T cells.
Impact:
- HSP 70 expression is more frequent in the sarcoplasm of DM muscle fibers compared to PM.
- Preferential HSP 70 expression in DM suggests a role in response to ischemic insults.
- Findings may aid in differentiating DM from PM and understanding disease pathogenesis.