Effects of immunosuppressive treatment on microsomal prostaglandin E synthase 1 and cyclooxygenases expression in muscle tissue of patients with polymyositis or dermatomyositis
2008

Effects of Immunosuppressive Treatment on Muscle Tissue in Myositis

Sample size: 22 publication 10 minutes Evidence: moderate

Author Information

Author(s): Korotkova M, Helmers S Barbasso, Loell I, Alexanderson H, Grundtman C, Dorph C, Lundberg I E, Jakobsson P-J

Primary Institution: Karolinska Institutet

Hypothesis

The study investigates the expression of microsomal prostaglandin E synthase 1 and cyclooxygenases in muscle biopsies from patients with polymyositis or dermatomyositis before and after immunosuppressive treatment.

Conclusion

Conventional immunosuppressive treatment led to a significant downregulation of COX-2 in myositis muscle tissue, while the expression of mPGES-1 and COX-1 remained unchanged.

Supporting Evidence

  • Increased expression of mPGES-1, COX-1, and COX-2 was observed in muscle tissue from patients with myositis compared to healthy individuals.
  • Conventional immunosuppressive treatment resulted in improved muscle function but still lower than normal.
  • A decreased number of CD68-positive macrophages and reduced COX-2 expression in muscle tissue was also seen after treatment.

Takeaway

Doctors looked at muscle samples from people with a disease that makes muscles weak to see how treatment affects certain proteins. They found that while one protein decreased with treatment, others stayed the same.

Methodology

Muscle biopsies were taken from patients and healthy individuals, and the expression of mPGES-1 and COX was evaluated using immunohistochemistry.

Limitations

The study had a small sample size and did not correlate enzyme expression with clinical outcomes effectively.

Participant Demographics

Patients included 9 with recently diagnosed myositis and 3 with treatment-resistant myositis, median age 54 years.

Statistical Information

P-Value

p<0.01

Statistical Significance

p<0.01

Digital Object Identifier (DOI)

10.1136/ard.2007.079525

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