Figure 1.

Schematic of the macrophage and Schwann cell response in peripheral nerve injury.

(A) Neutrophils and monocytes infiltrate the injury site within hours post-injury. This process is initiated by chemokines being released from local cells, including dedifferentiating Schwann cells. (B) Recruited monocytes differentiate into phagocytic macrophages whereby, among other things, they play a well-established and indispensable role in engulfing debris. We hypothesize that the dedifferentiated Schwann cell plays a substantial role in regulating macrophage function, via the secretion of cytokines/factors, although the mechanisms that underlie this regulation remain undetermined. (C) The macrophage's pro-regenerative role involves direct regulation of several cellular events via the secretion of anti-inflammatory/growth supportive cytokines. We hypothesize this includes the regulation of Schwann cell differentiation, the promotion of Schwann cell remyelination, axonal support and angiogenesis.