Induced pluripotent stem cells in rat models of Parkinson's disease: A systematic review and meta‑analysis

The effects of induced pluripotent stem cells (iPSCs) in 6-hydroxydopamine-lesioned rat models of Parkinson's disease (PD) have been evaluated in multiple studies. However, the results evaluating the effectiveness of iPSCs in animal models of PD are mixed, primarily due to their low statistical power. In the current study, a meta-analysis was performed to describe the treatment effect of unsorted iPSCs on behavioral testing in experimental rat models of PD. Databases searched included PubMed, EMBASE, MEDLINE and the Cochrane Library from inception to March 2017. Data were extracted for rotation behavior tests (induced by amphetamine and apomorphine) and limb function tests. A total of eight studies were included in the current meta-analysis, and iPSCs were identified to be efficacious according to the pooled standardized mean differences (SMDs) for improving amphetamine-induced rotational behavior [SMD, -2.16; 95% confidence interval (95% CI), -2.93, -1.40; P<0.00001] and apomorphine-induced rotational test (SMD, -1.45; 95% CI, -2.16, -0.73; P<0.0001). The pooled evidence indicated that iPSCs improve rotational behavior in rat models of PD. It was concluded that iPSCs provide a potential approach for developing novel treatment strategies for PD, and the results of this meta-analysis may guide future preclinical and clinical studies.