Human mesenchymal stem cells isolated from Wharton's jelly of the umbilical cord were induced to transform into dopaminergic neurons in vitro through stepwise culturing in neuron-conditioned medium, sonic hedgehog, and FGF8. The success rate was 12.7%, as characterized by positive staining for tyrosine hydroxylase (TH), the rate-limiting catecholaminergic synthesizing enzyme, and dopamine being released into the culture medium. Transplantation of such cells into the striatum of rats previously made Parkinsonian by unilateral striatal lesioning with the dopaminergic neurotoxin 6-hydroxydopamine partially corrected the lesion-induced amphetamine-evoked rotation. Viability of the transplanted cells at least 4 months after transplantation was identified by positive TH staining and migration of 1.4 mm both rostrally and caudally. These results suggest that human umbilical mesenchymal stem cells have the potential for treatment of Parkinson's disease. STEM CELLS 2006; 24:115-124

BackgroundHuman umbilical mesenchymal stem cells (HUMSCs) isolated from Wharton's jelly of the umbilical cord can be easily obtained and processed compared with embryonic or bone marrow stem cells. These cells may be a valuable source in the repair of spinal cord injury.Methodology/Principal FindingsWe examine the effects of HUMSC transplantation after complete spinal cord transection in rats. Approximately 5×105 HUMSCs were transplanted into the lesion site. Three groups of rats were implanted with either untreated HUMSCs (referred to as the stem cell group), or HUMSCs treated with neuronal conditioned medium (NCM) for either three days or six days (referred to as NCM-3 and NCM-6 days, respectively). The control group received no HUMSCs in the transected spinal cord. Three weeks after transplantation, significant improvements in locomotion were observed in all the three groups receiving HUMSCs (stem cell, NCM-3 and NCM-6 days groups). This recovery was accompanied by increased numbers of regenerated axons in the corticospinal tract and neurofilament-positive fibers around the lesion site. There were fewer microglia and reactive astrocytes in both the rostral and caudal stumps of the spinal cord in the stem cell group than in the control group. Transplanted HUMSCs survived for 16 weeks and produced large amounts of human neutrophil-activating protein-2, neurotrophin-3, basic fibroblast growth factor, glucocorticoid induced tumor necrosis factor receptor, and vascular endothelial growth factor receptor 3 in the host spinal cord, which may help spinal cord repair.Conclusions/SignificanceTransplantation of HUMSCs is beneficial to wound healing after spinal cord injury in rats.

We investigated the effect of human umbilical mesenchymal stem cells (HUMSCs) from Wharton's jelly on carbon tetrachloride (CCl 4 )-induced liver fibrosis in rats. Rats were treated with CCl 4 for 4 weeks, and this was followed by a direct injection of HUMSCs into their livers. After 4 more weeks of CCl 4 treatment (8 weeks in all), rats with HUMSC transplants [CCl 4 (8W)ϩHUMSC liver] exhibited a significant reduction in liver fibrosis, as evidenced by Sirius red staining and a collagen content assay, in comparison with rats treated with CCl 4 for 8 weeks without HUMSC transplants [CCl 4 (8W)]. Moreover, rats in the CCl 4 (8W)ϩHUMSC (liver) group had significantly lower levels of serum glutamic oxaloacetic transaminase, glutamic pyruvate transaminase, ␣-smooth muscle actin, and transforming growth factor-␤1 in the liver, whereas the expression of hepatic mesenchymal epithelial transition factor-phosphorylated type (Met-P) and hepatocyte growth factor was up-regulated, in comparison with the CCl 4 (8W) group. Notably, engrafted HUMSCs scattered mostly in the hepatic connective tissue but did not differentiate into hepatocytes expressing human albumin or ␣-fetoprotein. Instead, these engrafted, undifferentiated HUMSCs secreted a variety of bioactive cytokines that may restore liver function and promote regeneration. Human cytokine assay revealed that the amounts of human cutaneous T cell-attracting chemokine, leukemia inhibitory factor, and prolactin were substantially greater in the livers of the CCl 4 (8W)ϩHUMSC (liver) group, with considerably reduced hepatic inflammation manifested by a micro positron emission tomography scan. Our findings suggest that xenogeneic transplantation of HUMSCs is a novel approach for treating liver fibrosis and may be a promising therapeutic intervention in the future. Liver Transpl 15: 484-495, 2009.