This method for derivation of DA neurons was then further refined to about. 80% DA differentiation through transgenic expression of Nurr-1 in combination with FG.F2, SHH, FGF8, and ascorbic acid treatment.47 Using a similar Nurr-1 transgenic approach, the McKay

group later showed functional effects of such in vitro ES cell-derived DA neurons in a rat. model of PD.48 By differentiating the ES cells from DA neurons prctransplantation, these authors this website claimed that, they could avoid the teratoma issue seen using undifferentiated ES cells.45 Unfortunately, teratomas can still develop even when cells are prediffercntiated in vitro,49 probably due to contamination of remaining undifferentiated Inhibitors,research,lifescience,medical ES cells within the cultures. Other protocols for the in vitro derivation of DA neurons from ES cells have been established. Kawasaki et al showed that, yet unknown soluble factors (named stromal cell-derived inducing activity [SDIA]) from the PA6 stromal cell line could facilitate DA differentiation in approximately Inhibitors,research,lifescience,medical 30% to 35% of the neurons derived from ES cells; unfortunately, these DA neurons survived very poorly after grafting into the brain.50 Barbieri et al used

Inhibitors,research,lifescience,medical MS5 stromal feeder cells in combination with SHH, FGF8, ascorbic acid, and brain-derived neurotrophic factor (BDNF) treatment to obtain approximately 50% DA differentiation from normal mouse ES cells41; similar results have also been obtained from nuclear transfer-derived ES cells.41,51 Furthermore, Ying et al described “significant.” DA differentiation using monolayer ES cell cultures in combination with SHH, FGF8, and FGF2 treatment.52 Thus, many recent, Inhibitors,research,lifescience,medical reports have now made it

clear that Inhibitors,research,lifescience,medical efficient generation (30% -80%) of DA neurons can be achieved from mouse ES cells and that such cells can survive, integrate, and show functional effects in rodent, models of PD.45,48 Primate (nonhuman and human) ES cells On the basis of the encouraging results from mouse ES cells and Thomson’s successful generation of nonhuman primate53,54 and human ES cell Adenosine lines,55 several labs started to investigate the possibilities of making DA neurons from primate ES cells. Kawasaki et al created DA neurons from nonhuman primate ES cells using PA6 cells and SDIA,56 and Vrana et al showed DA differentiation from nonhuman primate parthenogenetic stem cells (Cyno-1 cells).57 The in vitro derivation of a smaller number of DA neurons from human ES cells was described by three different groups in 2001.58-60 We are now eagerly awaiting the first convincing demonstration of human ES cell-derived functional DA neurons in rodent, or primate models of PD. EG cells Embryonic germ (EG) cell lines are pluripotent, selfrenewing stem cells with many similarities to ES cells.