Reducing myeloperoxidase activity decreases inflammation and increases cellular protection in ischemic stroke

Area of Science:

• Neuroscience
• Immunology
• Pharmacology

Background:

• Myeloperoxidase (MPO) is a pro-inflammatory enzyme released by myeloid cells during stroke.
• Elevated MPO activity contributes to brain damage post-stroke.

Purpose of the Study:

• To investigate the therapeutic potential of MPO inhibition in a mouse model of stroke.
• To determine the effects of MPO inhibition on cell survival, inflammation, and neurological outcomes.

Main Methods:

• Utilized wildtype (WT) mice treated with MPO inhibitor 4-aminobenzoic acid hydrazide (ABAH) and MPO-deficient (MPO-/-) mice.
• Administered ABAH during and after induced ischemic stroke.
• Assessed cell loss (neurons, oligodendrocytes), myeloid cell activation, and expression of key proteins (Hsp70, p-Akt, p53).
• Evaluated neurological deficits and infarct size.

Main Results:

• MPO inhibition or deficiency significantly decreased neuronal and oligodendrocyte loss in ischemic brains.
• Reduced myeloid cell activation was observed with MPO inhibition.
• Increased levels of cytoprotective Hsp70 and p-Akt, with decreased p53, were noted.
• Significant improvements in neurological function and reduced infarct size were achieved with MPO inhibition, even with delayed treatment.

Conclusions:

• MPO inhibition confers neuroprotection by reducing inflammation and enhancing survival pathways.
• Delayed MPO inhibition demonstrates efficacy, suggesting a therapeutic window extending beyond the acute stroke phase.
• MPO inhibition represents a promising therapeutic strategy for stroke, potentially applicable days after the event.