Radiolabeling of umbilical cord-derived mesenchymal stem cells for in vivo tracking.

Non-invasive methods for the assessment of distribution, homing, and retention of stem cells are desired for the successful demonstration of stem cell therapy. Cells labeled with (99m)Tc, (18)F, and (111)In have been reported for tracking the cells in vivo. However, they can be tracked only for a limited time due to the short half lives of these isotopes. In this context, stem cells labeled with (51)Cr would be appropriate for tracking cells for a longer period of time owing to their half life of 27.7 days. Here, we have isolated mesenchymal stem cells (MSCs) from umbilical cord tissue, characterized them, and attempted to radiolabel them with (51)Cr for mapping the fate of transplanted MSC cells after an intravenous injection via the tail vein in small animals.

Tansplantation of autologous bone marrow derived mesenchymal stem cells trans-epicardially in patients undergoing coronary bypass surgery.

BACKGROUND: Myocardial Infarction (MI) hampers cardiac performance by ventricular remodeling which is a major cause of heart failure or death. Conventional drug therapies like beta blockers, angiotensin-converting enzyme may delay remodeling but there is no single therapeutic regimen available that can prevent or reverse the process of myocardial injury. Interventional therapies and surgical procedures improve or normalize coronary blood flow greatly. Experimental data suggests that bone marrow derived Mesenchymal Stem Cells (MSCs) may contribute to the healing of Myocardial infarction. We present our findings on the use of bone marrow derived MSCs for Myocardial Infarction wherein the cells were injected in and around the infarct region epicardially during coronary bypass surgery. METHODS & MATERIALS: 31 patients selected to undergo Coronary Artery Bypass Graft (CABG) as a treatment option for myocardial infarction formed the subject matter of our study. One patient withdrew consent before receiving our therapy and was excluded from the study. 15 patients (all men, average age 57) formed the test arm who underwent CABG plus Bone Marrow Mesenchymal Stem Cells (BMMSCs) transplantation whereas another 15 patients underwent conventional CABG only (14 men and 1 woman, mean age 57) served as the control arm. The cell transplantation consisted of injecting BMMSCs in the border zone of the clearly visible infarcted area transepicardially. The absolute number of MSCs injected ranged between 3 million and 26 million cells. RESULTS: The data for change from baseline in the area of infarct was collected at 3 months and 6 months during the study and analyzed using paired t-tests. The mean percentage perfusion improvement from baseline in the area of infarct supplied by the Left Anterior Descending Artery (LAD) was higher in the cases (35.8%) as compared to the controls (11.3%) at 3 months post treatment (p value < 0.05). There were three cases of arrhythmia, and none of the adverse events recorded were due to the investigational product. Improvement in the ejection fraction was similar in the cases and controls. CONCLUSIONS: This study demonstrates that trans-epicardial uses of mesenchymal stem cells are very safe and feasible. Correction of perfusion defect is very encouraging. Larger studies using higher doses of mesenchymal stem cells may bring about better understanding.

Immunologic properties of human dermal fibroblasts.

Human dermal fibroblasts are known not to express human leukocyte antigen (HLA)-DR message or protein in the absence of interferon (IFN)-γ. To use allogeneic dermal fibroblasts for cell therapy, as a revalidation, the cells at passage 12 were analyzed for HLA-DR mRNA and surface protein. Although no significant HLA-DR surface protein was found, HLA-DR mRNA expression was observed, without interferon-γ. At an early passage, although HLA-DR surface protein was not found, prominent expression of HLA-DR mRNA was observed without IFN-γ stimulation, which was not typical of dermal fibroblasts studied so far. Intracytoplasmic HLA-DR protein was also not detected, which suggests that the mRNA was not translated. There was no marked stimulation of T-cell proliferation by the fibroblasts in the absence or presence of IFN-γ. Interestingly, indoleamine dioxygenase, a molecule involved in immunosuppression, was also expressed in dermal fibroblasts in the absence of IFN-γ.

Immunosuppressive properties of human umbilical cord-derived mesenchymal stem cells: role of B7-H1 and IDO.

Umbilical cord is a rich source of mesenchymal stromal or stem cells (MSCs) that can be used for developing allogeneic cell therapy to treat intractable diseases. In this report, we present evidence that umbilical cord-derived MSCs (UCMSCs) possess important immunomodulatory properties that may enable them to survive in an allogeneic environment. UCMSCs do not express human leukocyte antigen (HLA)-DR and co-stimulatory molecules CD80 and CD86 that are required for T-cell activation. More importantly, UCMSCs constitutively express a negative regulator of T-cell activation, B7-H1, and its expression is increased after interferon-γ (IFN-γ) treatment. In addition, IFN-γ treatment induced indoleamine 2,3-dioxygenase (IDO) and HLA-DR expression in UCMSCs. Neither control nor IFN-γ-treated UCMSCs stimulated allogeneic T-cell proliferation, and both cell populations inhibited third-party dendritic cell (DC)-mediated allostimulatory activity. Addition of a B7-H1-specific blocking antibody or an IDO inhibitor, 1 methyl tryptophan (1-MT) abrogated the T-cell immunosuppressive activity of these cells. Furthermore, UCMSCs prevented the differentiation and maturation of peripheral blood monocyte-derived DCs, and augmented the generation of regulatory T cells (Tregs) in culture. The immunosuppressive effects of UCMSCs are largely mediated by cell-to-cell contact, although some inhibitory activity was observed with cell-free supernatant. Our study suggests that these immunomodulatory properties of UCMSCs could potentially improve the outcome of allogeneic stem cell therapy.

Umbilical cord matrix derived mesenchymal stem cells can change the cord blood transplant scenario.

BACKGROUND AND OBJECTIVES: The field of Umbilical cord blood (UCB) hematopoietic stem cell transplantation has had an amazing run since 1988. UCB is being increasing used in related and unrelated transplant settings. A major hurdle, however, in the use of UCB is its low cell dose, which is largely responsible for an elevated risk of graft failure and significantly delayed neutrophils and platelet engraftment. Strategies to increase CD34(+) HSC/HPC dose are under development as a direct correlation has been shown between these counts and time for engraftment. One strategy includes the ex vivo expansion of UCB derived CD34(+) cells. METHODS AND RESULTS: We show that the umbilical cord derived mesenchymal stem cells (UCMSCs) can be used as supporting cells for ex vivo expansion of CD34(+) cells using low concentrations of cytokine cocktail. The UCMSCs release the cytokines required for maintenance and proliferation of CD34(+) cells in the ex vivo culture conditions. More than 25 fold increase in total nucleated cell count (TNC) and more than 20 fold increase in CD34(+) cell count has been obtained using this co-culture system. CONCLUSIONS: UCMSCs from both, autologous and allogeneic origin can be used for expansion of UCB derived CD34(+) cells. The ease of availability and immunoprivileged nature of UCMSCs further holds promise in their use in an allogeneic transplant setting.

Characterization and in vitro differentiation potential of a new human embryonic stem cell line, ReliCellhES1.

Human embryonic stem cells (hESCs) are an exceptionally useful tool for studies of human development and represent a potential source for transplantation therapies. At present, only a limited number of hESCs lines representing a very small sample of genetic diversity of the human populations are available. Here, we report the derivation and characterization of a new hESC line, ReliCellhES1. These cells, established from the inner cell mass (ICM) on mouse embryonic feeder (MEF) layer, satisfy the criteria that characterize pluripotent hESCs: The cell line expresses high levels of cell surface markers (such as SSEA-3, SSAEA-4, TRA-1-60 and TRA-1-81), transcription factor Oct-4, alkaline phosphatase (AP) and telomerase. The cell line retains normal karyotype in long-term culture and has a distinct identity as revealed by DNA fingerprinting by short tandem repeat (STR) analysis. Further, upon examination of the in vitro differentiation potential, ReliCellhES1 was found to be capable of giving rise to dopaminergic neurons, cardiomyocytes, pancreatic islets, and hepatocyte-like cells belonging to ectoderm, mesoderm, and endoderm lineages, respectively. To our knowledge, this is the first report of a well-characterized hES cell line from the Indian subcontinent.

The transdifferentiation potential of limbal fibroblast-like cells.

We report the identification and isolation of limbal fibroblast-like cells from adult corneo-limbal tissue possessing self-renewing capacity and multilineage differentiation potential. The cells form cell aggregates or clusters, which express molecular markers, specific for ectoderm, mesoderm and endoderm lineages in vitro. Further, these cells mature into a myriad of cell types including neurons, corneal cells, osteoblasts, chondrocytes, adipocytes, cardiomyocytes, hepatocytes and pancreatic islet cells. Despite originating from a non-embryonic source, they express ESC and other stem cell markers important for maintaining an undifferentiated state. This multipotential capability, relatively easy isolation and high rate of ex vivo proliferation capacity make these cells a promising therapeutic tool.