Several studies have examined the enhanced efficacy of neurotrophic factor - transfected mesenchymal stem cells (MSCs) in ischemic rat models. However, gene therapy, i.e., the application of MSCs transfected with neurotrophic factors, is not feasible in clinical practice for safety issue. Thus, these hypothesized that besides genetic manipulation, ex vivo cultivation with specific trophic factors per se might also enhance the efficacy of human MSCs (hMSCs) in an animal model of ischemic stroke. The stroke rat model was performed from 2 hrs transient middle cerebral artery occlusion (tMCAo). The intravenous application of ex vivo - cultured hMSCs was performed at 24 hrs after tMCAo. The ischemic brains were extracted from the injured hemisphere at one day after tMCAo. The ischemic brain-extracts were treated after 2 days of hMSCs culture, and media of cultured hMSCs with ischemic brain-extracts was collected for 7 days. The trophic factors, such as BDNF, NGF, VEGF, HGF, and bFGF, levels were analyzed using ELISA. The each trophic factor was pretreated in ex vivo culture conditions of hMSCs. Trophic factor treated hMSCs were re-seeded and cultured with ischemic brain extracts. Concentrations of each trophic factor were measured and compared between the trophic factor - treated and the non - treated hMSCs. Tissue
levels of trophic factor, in all case, were higher in hMSCs - received ischemic brain than in non - received ischemic brain. In addition, hMSCs cultured with ischemic rat brain extract increased production of BDNF, VEGF, and HGF. When the BDNF, VEGF, and HGF - treated hMSCs received ischemic brain -extracts, the released levels of trophic factor were significantly high than those that trophic factor non - treated hMSCs. These data suggested that hMSCs provide the trophic support to ischemic brain and it can be enhanced by ex vivo treatment of trophic factor. These results indicate that hMSCs transplantation may be clinically useful as a potential therapy for stroke.