Reversal of bleomycin-induced rat pulmonary fibrosis by a xenograft of human umbilical mesenchymal stem cells from Wharton's jelly.

Pulmonary fibrosis (PF) is a progressive and irreversible condition with various causes, and no effective treatment has been found to rescue fibrotic lungs. Successful recovery from PF requires inhibiting inflammation, promoting collagen degradation and stimulating alveolar regeneration. Human umbilical mesenchymal stem cells (HUMSCs) not only regulate immune responses but also synthesize and release hyaluronan to improve lung regeneration. This study investigated the feasibility of HUMSC engraftment into rats with bleomycin (BLM)-induced PF to explore HUMSC therapeutic effects/outcomes. Methods: A unique BLM-induced left-lung-dominated PF animal model was established. Rats were transplanted with low-dose (5×106) or high-dose (2.5×107) HUMSCs on Day 21 after BLM injection. Combinations in co-culture of pulmonary macrophages, fibroblasts, HUMSCs treated with BLM and the same conditions on alveolar epithelia versus HUMSCs were evaluated. Results: Rats with high-dose HUMSC engraftment displayed significant recovery, including improved blood oxygen saturation levels and respiratory rates. High-dose HUMSC transplantation reversed alveolar injury, reduced cell infiltration and ameliorated collagen deposition. One month posttransplantation, HUMSCs in the rats' lungs remained viable and secreted cytokines without differentiating into alveolar or vascular epithelial cells. Moreover, HUMSCs decreased epithelial-mesenchymal transition in pulmonary inflammation, enhanced macrophage matrix-metallopeptidase-9 (MMP-9) expression for collagen degradation, and promoted toll-like receptor-4 (TLR-4) expression in the lung for alveolar regeneration. In coculture studies, HUMSCs elevated the MMP-9 level in pulmonary macrophages, released hyaluronan into the medium and stimulated the TLR-4 quantity in the alveolar epithelium. Principal Conclusions: Transplanted HUMSCs exhibit long-term viability in rat lungs and can effectively reverse rat PF.

The Therapeutic Potential of Human Umbilical Mesenchymal Stem Cells From Wharton's Jelly in the Treatment of Rat Peritoneal Dialysis-Induced Fibrosis.

A major complication in continuous, ambulatory peritoneal dialysis in patients with end-stage renal disease who are undergoing long-term peritoneal dialysis (PD) is peritoneal fibrosis, which can result in peritoneal structural changes and functional ultrafiltration failure. Human umbilical mesenchymal stem cells (HUMSCs) in Wharton's jelly possess stem cell properties and are easily obtained and processed. This study focuses on the effects of HUMSCs on peritoneal fibrosis in in vitro and in vivo experiments. After 24-hour treatment with mixture of Dulbecco's modified Eagle's medium and PD solution at a 1:3 ratio, primary human peritoneal mesothelial cells became susceptible to PD-induced cell death. Such cytotoxic effects were prevented by coculturing with primary HUMSCs. In a rat model, intraperitoneal injections of 20 mM methylglyoxal (MGO) in PD solution for 3 weeks (the PD/MGO 3W group) markedly induced abdominal cocoon formation, peritoneal thickening, and collagen accumulation. Immunohistochemical analyses indicated neoangiogenesis and significant increase in the numbers of ED-1- and α-smooth muscle actin (α-SMA)-positive cells in the thickened peritoneum in the PD/MGO 3W group, suggesting that PD/MGO induced an inflammatory response. Furthermore, PD/MGO treatment for 3 weeks caused functional impairments in the peritoneal membrane. However, in comparison with the PD/MGO group, intraperitoneal administration of HUMSCs into the rats significantly ameliorated the PD/MGO-induced abdominal cocoon formation, peritoneal fibrosis, inflammation, neoangiogenesis, and ultrafiltration failure. After 3 weeks of transplantation, surviving HUMSCs were found in the peritoneum in the HUMSC-grafted rats. Thus, xenografts of HUMSCs might provide a potential therapeutic strategy in the prevention of peritoneal fibrosis. Significance: This study demonstrated that direct intraperitoneal transplantation of human umbilical mesenchymal stem cells into the rat effectively prevented peritoneal dialysis/methylglyoxal-induced abdominal cocoon formation, ultrafiltration failure, and peritoneal membrane alterations such as peritoneal thickening, fibrosis, and inflammation. These findings provide a basis for a novel approach for therapeutic benefits in the treatment of encapsulating peritoneal sclerosis.

A high-efficiency induction of dopaminergic cells from human umbilical mesenchymal stem cells for the treatment of hemiparkinsonian rats.

The success rate in previous attempts at transforming human umbilical mesenchymal stem cells (HUMSCs) isolated from Wharton's jelly of the umbilical cord into dopaminergic cells was a mere 12.7%. The present study was therefore initiated to establish a more effective procedure for better yield of dopaminergic cells in such transformation for more effective HUMSC-based therapy for parkinsonism. To examine, in vitro, the effects of enhanced Nurr1 expression in HUMSCs on their differentiation, cells were processed through the three-stage differentiation protocol. The capacity of such cells to synthesize and release dopamine was measured by HPLC. The therapeutic effects of Nurr1-overexppressed HUMSCs were examined in 6-hydroxydopamine-lesioned rats by quantification of rotations in response to amphetamine. Enhanced Nurr1 expression in HUMSCs promoted the transformation into dopaminergic cells in vitro through stepwise culturing in sonic hedgehog, fibroblast growth factor-8, and neuron-conditioned medium. The success rate was about 71%, as determined by immunostaining for tyrosine hydroxylase and around 94 nM dopamine synthesis (intracellular and released into the culture medium), as measured by HPLC. Additionally, transplantation of such cells into the striatum of hemiparkinsonian rats resulted in improvement of their behavioral deficits, as indicated by amphetamine-evoked rotation scores. Viability of the transplanted cells lasted for at least 3 months as verified by positive staining for tyrosine hydroxylase. Nurr1, FGF8, Shh, and NCM can synergistically enhance the differentiation of HUMSCs into dopaminergic cells and may pave the way for HUMSC-based treatments for Parkinson's disease.

Human umbilical mesenchymal stem cells promote recovery after ischemic stroke.

BACKGROUND AND PURPOSE: Stroke is a cerebrovascular defect that leads to many adverse neurological complications. Current pharmacological treatments for stroke remain unclear in their effectiveness, whereas stem cell transplantation shows considerable promise. Previously, we have shown that human umbilical mesenchymal stem cells (HUMSCs) can differentiate into neurons in neuronal-conditioned medium. Here we evaluate the therapeutic potential of HUMSC transplantation for ischemic stroke in rats. METHODS: Focal cerebral ischemia was produced by middle cerebral artery occlusion and reperfusion. The HUMSCs treated with neuronal-conditioned medium or not treated were transplanted into the ischemic cortex 24 hours after surgery. RESULTS: Histology and MRI revealed that rats implanted with HUMSCs treated with neuronal-conditioned medium or not treated exhibited a trend toward less infarct volume and significantly less atrophy compared with the control group, which received no HUMSCs. Moreover, rats receiving HUMSCs showed significant improvements in motor function, greater metabolic activity of cortical neurons, and better revascularization in the infarct cortex. Implanted HUMSCs, treated or not treated, survived in the infarct cortex for at least 36 days and released neuroprotective and growth-associated cytokines, including brain-derived neurotrophic factor, platelet-derived growth factor-AA, basic fibroblast growth factor, angiopoietin-2, CXCL-16, neutrophil-activating protein-2, and vascular endothelial growth factor receptor-3. CONCLUSIONS: Our results demonstrate the therapeutic benefits of HUMSC transplantation for ischemic stroke, likely due to the ability of the cells to produce growth-promoting factors. Thus, HUMSC transplantation may be an effective therapy in the future.

The therapeutic potential of human umbilical mesenchymal stem cells from Wharton's jelly in the treatment of rat liver fibrosis.

We investigated the effect of human umbilical mesenchymal stem cells (HUMSCs) from Wharton's jelly on carbon tetrachloride (CCl4)-induced liver fibrosis in rats. Rats were treated with CCl4 for 4 weeks, and this was followed by a direct injection of HUMSCs into their livers. After 4 more weeks of CCl4 treatment (8 weeks in all), rats with HUMSC transplants [CCl4 (8W)+HUMSC 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 CCl4 for 8 weeks without HUMSC transplants [CCl4 (8W)]. Moreover, rats in the CCl4 (8W)+HUMSC (liver) group had significantly lower levels of serum glutamic oxaloacetic transaminase, glutamic pyruvate transaminase, alpha-smooth muscle actin, and transforming growth factor-beta1 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 CCl4 (8W) group. Notably, engrafted HUMSCs scattered mostly in the hepatic connective tissue but did not differentiate into hepatocytes expressing human albumin or alpha-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 CCl4 (8W)+HUMSC (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.