Modification of platelet aggregation by leukocytes in acute ischemic stroke

Area of Science:

• Hematology
• Neurology
• Immunology

Background:

• Platelet aggregation is crucial in thromboembolic cerebrovascular disease pathogenesis.
• Leukocytes can modulate platelet aggregability, either stimulating or inhibiting it.

Purpose of the Study:

• To investigate the influence of leukocytes on collagen-induced platelet aggregation in acute ischemic stroke patients.
• To compare platelet aggregation in stroke patients versus healthy controls.

Main Methods:

• Studied 23 acute ischemic stroke patients and 23 age/sex-matched healthy controls.
• Measured collagen-induced platelet aggregation in platelet-rich plasma.
• Assessed the effect of adding polymorphonuclear or mononuclear leukocytes.

Main Results:

• Platelet aggregation without leukocytes was slightly lower in patients (P=.06).
• Mononuclear leukocytes significantly reduced (P=.018) and polymorphonuclear leukocytes tended to reduce (P=.06) platelet aggregation in patients.
• Leukocyte presence significantly lowered platelet aggregation in patients compared to controls (P=.004 for mononuclear, P=.008 for polymorphonuclear).
• The ratio of polymorphonuclear leukocytes to platelets was higher in patients (P<.001).

Conclusions:

• Mononuclear and, to a lesser extent, polymorphonuclear leukocytes exhibit platelet aggregation-inhibiting potential in early ischemic stroke.
• This leukocyte-mediated inhibition may represent an antithrombotic mechanism in acute stroke.