Although evidence of damage-directed neural stem cell (NSC) migration has been well-documented in the rodent, to our knowledge it has by no means been confirmed or quantified using human NSC (hNSC) in an adult non-human primate modeling a human neurodegenerative disease state. models of PD, most studies to date have focused on cells implanted directly into the striatum, recapitulating earlier studies using dopaminergic fetal tissue transplant techniques. They statement mainly on NSC which remained in the striatum (the site of lost dopaminergic input) (Burnstein et al., 2004; Wu et al., 2006; Ourednik et al., 2002; VX-950 Zhou et al., 2003). When migration from the implant site was noted, the authors explained NSC that migrated occasionally a short distance from the striatum via the corpus callosum, but a detailed description of their destination was not reported (Dziewczapolski et al., VX-950 2004; Liker et al., 2003; Wang et al., 2004). NSCs designed to over express glial produced neurotrophic factor (GDNF) or nurturin also did not substantially migrate beyond the striatum but nevertheless improved motor function through retrograde transport of these trophic factors to the substantia nigra (SN) (Liu et al., 2006; Behrstock et al., 2006). So, unlike studies of other neurodegenerative disorders (i.at the. ischemia, multiple sclerosis), a detailed description of NSC migration in models of PD is usually lacking. Building on prior rodent studies, we implanted human NSCs (hNSCs) into MPTP-lesioned, dopamine-depleted, non-human primates. We previously detailed the phenotypical fate of those donor cells, their impact upon host dopaminergic neurons, and functional benefits (Bjugstad et al., 2005; Redmond et al., 2007). In some IKBKB antibody monkeys, the fate of transplanted hNSCs after >8 months in vivo was analyzed (Redmond et al., 2007). We found common migration of hNSCs throughout the brain, particularly to regions impaired directly or indirectly by MPTP with neuronal differentiation of a small proportion of NSCs appropriate to the site of migration (Redmond et al., 2007). In another set of MPTP-treated monkeys implanted with fewer hNSC and shorter survival occasions (4 months or 7 months) we found no neuronal differentiation, but there were reversals of MPTP-induced changes in the caudate and putamen and a specific NSC migration pattern (Bjugstad et al., 2005). Hypothesizing that NSC migration in this model is usually not a random event, but rather a strategic self-positioning, we pursued a detailed quantitative analysis of hNSC migration patterns in the MPTP-lesioned monkey model of PD from the two shorter time points following transplantation. This analysis provided us with an opportunity to learn more about the hNSC migratory process in general. In so doing, we hoped to help advance stem cell concepts toward clinical relevance by providing the needed confirmation that the damage-directed NSC migration documented in the rodent does, indeed, apply to human neural stem cells in an adult non-human primate with neuropathology comparable to Parkinsons disease in patients. Methods Cell Isolation and Preparation Human neural stem cells (hNSC) were used for transplantation into MPTP-exposed monkeys. hNSC were isolated, expanded, cultured, and VX-950 prepared for transplantation as previously explained (Flax et al., 1998; Lee et al, 2007; Redmond et al, 2007). Briefly, a main dissociated neural cell suspension was cultured from the periventricular region of the telencephalon from a 13 week human fetal cadaver. Cells were produced in the beginning in serum and then were switched to serum-free conditions made up of basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF). These growth factors can substitute for serum in maintaining proliferation of hNSC and mimic the developmental sequence of growth factor dependence for hNSC (Kitchens et al., 1994; Teng et al., 2001). Once a populace of hNSCs was expanded, suspensions were plated on uncoated tissue culture dishes in growth media (Dulbeccos Modified Eagles Medium (DMEM) + F12 (1:1) supplemented with N2 medium.