Abstract

RATIONALE: The mechanisms leading to an expanded neutrophil and monocyte supply after stroke are incompletely understood.
OBJECTIVE: To test the hypothesis that transient middle cerebral artery occlusion (tMCAO) in mice leads to activation of hematopoietic bone marrow stem cells.
METHODS AND RESULTS: Serial in vivo bioluminescence reporter gene imaging in mice with tMCAO revealed that bone marrow cell cycling peaked 4 days after stroke (P CONCLUSIONS: Ischemic stroke activates hematopoietic stem cells via increased sympathetic tone, leading to a myeloid bias of hematopoiesis and higher bone marrow output of inflammatory Ly6C(high) monocytes and neutrophils.