Using canonical molecular indicators of macrophage phenotype, recent studies have identified M1 and M2 macrophages in the pathological brain and spinal cord (Kigerl et al., 2009; Mandrekar-Colucci and Landreth, 2010; Kumar et al., 2013). In many models of neurologic disease, the magnitude of pathology or functional loss correlates with a robust M1 macrophage response, and blocking inflammatory signaling often confers neuroprotection (Colton and Wilcock, 2010; David and Kroner, 2011; Shechter and Schwartz, 2013). Similarly, functional inhibition or acute depletion of macrophages in rats and mice after traumatic SCI is neuroprotective and promotes functional recovery (Giulian and Robertson, 1990; Blight, 1994; Popovich et al., 1999; Gris et al., 2004)
