Oxides and apoptosis in inflammatory myopathies

Area of Science:

• Muscle Inflammation
• Autoimmune Diseases
• Cellular Pathology

Background:

• Reactive oxygen intermediates (ROI) and nitric oxide (NO) are elevated in polymyositis (PM), dermatomyositis (DM), and inclusion body myositis (IBM).
• The precise role of ROI and NO in the pathogenesis of these autoimmune muscle diseases remains undetermined.
• Unlike demyelinating neuropathies, evidence for oxide-induced apoptosis in inflammatory myopathies is lacking.

Purpose of the Study:

• To investigate the role of reactive oxygen intermediates and nitric oxide in the pathogenesis of inflammatory myopathies.
• To explore the potential protective effects of nitric oxide at low concentrations.
• To identify mechanisms of apoptosis resistance in affected cells.

Main Methods:

• Analysis of reactive oxygen intermediate and nitric oxide production in inflammatory myopathies.
• Assessment of apoptosis in myocytes and inflammatory cells.
• Evaluation of anti-apoptotic protein expression, such as Bcl-2.

Main Results:

• No clear evidence for oxide-induced apoptosis in myocytes or inflammatory cells in PM, DM, and IBM.
• Low concentrations of nitric oxide may exert cell-protective effects.
• Upregulation of anti-apoptotic proteins like Bcl-2 appears to be a key survival mechanism.

Conclusions:

• The pathogenic role of reactive oxygen intermediates and nitric oxide in inflammatory myopathies requires further elucidation.
• Antioxidative and anti-apoptotic therapies should be used cautiously until the specific roles of oxides and apoptosis are resolved in individual cases.
• Bcl-2 upregulation is a significant factor in protecting myocytes and inflammatory cells from apoptosis.