Polymorphonuclear leukocyte behavior in a nonhuman primate focal ischemia model

Area of Science:

• Neuroscience
• Immunology
• Vascular Biology

Background:

• Polymorphonuclear (PMN) leukocytes play a role in focal cerebral infarction.
• Surgical preparation for ischemia models may affect leukocyte reactivity, complicating research interpretation.

Purpose of the Study:

• To prospectively examine the effects of surgical preparation and ischemia/reperfusion on granulocyte function in a baboon model.
• To determine if surgical procedures alter PMN leukocyte responses relevant to stroke research.

Main Methods:

• Baboons underwent surgical preparation for middle cerebral artery occlusion/reperfusion.
• Leukocyte function assays (polarization, O2.- production, beta-glucuronidase release, chemotaxis) were performed pre- and post-procedure.
• Comparison between nonsurgical controls, surgically prepared animals, and those undergoing occlusion/reperfusion.

Main Results:

• Surgical preparation caused a stress-related increase in circulating PMN leukocytes (p < 0.001).
• Surgical preparation alone did not impair PMN leukocyte function (polarization, O2.- production, beta-glucuronidase release) 24h post-op (p >= 0.4).
• Middle cerebral artery occlusion/reperfusion significantly reduced C5a-induced PMN leukocyte polarization.

Conclusions:

• Surgical preparation in baboons does not significantly alter key PMN leukocyte functions relevant to ischemia/reperfusion studies.
• Ischemia/reperfusion itself, however, does impact PMN leukocyte function, specifically polarization.
• Findings suggest careful consideration of the ischemia/reperfusion model's direct effects on leukocytes is necessary for accurate stroke research.