Wharton's Jelly Stem Cells Research Articles

Human umbilical cord Wharton's jelly stem cells and its conditioned medium support hematopoietic stem cell expansion ex vivo

Bone marrow mesenchymal stromal cells (BMMSCs) have been used as feeder support for the ex vivo expansion of hematopoietic stem cells (HSCs) but have the limitations of painful harvest, morbidity, and risk of infection to the patient. This prompted us to explore the use of human umbilical cord Wharton's jelly MSCs (hWJSCs) and its conditioned medium (hWJSC-CM) for ex vivo expansion of HSCs in allogeneic and autologous settings because hWJSCs can be harvested in abundance painlessly, are proliferative, hypoimmunogenic, and secrete a variety of unique proteins. In the presence of hWJSCs and hWJSC-CM, HSCs put out pseudopodia-like outgrowths and became highly motile. Time lapse imaging showed that the outgrowths helped them to migrate towards and attach to the upper surfaces of hWJSCs and undergo proliferation. After 9 days of culture in the presence of hWJSCs and hWJSC-CM, MTT, and Trypan blue assays showed significant increases in HSC numbers, and FACS analysis generated significantly greater numbers of CD34(+) cells compared to controls. hWJSC-CM produced the highest number of colonies (CFU assay) and all six classifications of colony morphology typical of hematopoiesis were observed. Proteomic analysis of hWJSC-CM showed significantly greater levels of interleukins (IL-1a, IL-6, IL-7, and IL-8), SCF, HGF, and ICAM-1 compared to controls suggesting that they may be involved in the HSC multiplication. We propose that cord blood banks freeze autologous hWJSCs and umbilical cord blood (UCB) from the same umbilical cord at the same time for the patient for future ex vivo HSC expansion and cell-based therapies.

Wharton's Jelly Stem Cells as Agents for Cancer Therapy

Stem cell based therapy has significant potential to treat various diseases including primary and metastatic cancers. The umbilical cord matrix stem cells (UCMSC) derived from human umbilical cord Wharton's jelly (also termed WJMSC) have been shown to exhibit low immunogenicity, which potentially negates immune consequences after cytotherapy. The homing ability of human and rat UCMSC to inflammatory tissues, including cancer tissues, further confers upon these cells the potential for targeted cancer therapy. Our previous studies demonstrated that un-engineered human and rat UCMSC significantly attenuated the growth of multiple cancer cell lines in vivo and in vitro through multiple mechanisms. We have also demonstrated that these cells can be engineered to express cytotoxic cytokines before being delivered to the tumor and can be preloaded with nanoparticle payloads and attenuate tumors after homing to them. In this review, intrinsic stem cell-dependent regulation of cancer growth, potential mechanisms involved in this unique biological function, delivery of exogenous anti-cancer agents, and the potential for clinical applications will be discussed.

Cardiac Differentiation of Human Wharton's Jelly Stem Cells – Experimental Comparison of Protocols

Cardiomyoplasty represents a promising approach for the repair of the injured heart, but is hampered by the availability of appropriate cells. Mesenchymal stem cells derived from the human umbilical cord tissue (UCMSC) can be obtained in large amounts without medical intervention, exhibit self renewal and immunological naivity as well as multipotency. In the present study, different published protocols of cardiac differentiation designed for different stem cell types were compared to differentiate UCMSC into cardiomyocyte-like cells (cUCMSC). Cardiac differentiation of UCMSC was driven by cell treatment with 5-azacytidine, oxytocin as well as by forming of embryoid bodies. The morphological and immunocytochemical analysis of cUCMSC with an extensive panel of cardiac markers showed that oxytocin is a more potent inducer of cardiac differentiation than 5-azacytidine and the forming of embryoid bodies. cUCMSC reveal a cardiomyocyte-like structure and the expression of cardiomyocyte associated proteins. The easy accessibility and the ability of UCMSC to differentiate into cells with characteristics of cardiomyocytes render UCMSC an attractive candidate for cell based therapies and cardiac tissue engineering.

Transplantation of Human Wharton's Jelly-Derived Stem Cells Alleviates Chemically Induced Liver Fibrosis in Rats

There is currently no effective treatment method available for liver fibrosis. We therefore evaluated the use of Wharton's jelly stem cells (WJSCs; the major umbilical cord stem cell population) to treat chemically induced liver fibrosis via intraperitoneal injection of thioacetamide. WJSCs were transplanted into liver-damaged rats via the portal vein and the treatment was evaluated by assessing serum biochemistry and histopathology. Transplanted WJSCs were distributed in the fibrotic area and around blood vessels, and hepatic recovery was accelerated. Serum prothrombin time significantly recovered, and serum albumin also improved at 21 days posttransplantation; collagen accumulation also decreased at 14 days. Thus, human WJSCs promoted recovery after chronic liver damage. Using immunohistochemical analyses, we determined that transplanted WJSCs produce albumin, hepatocyte growth factor (HGF), and metalloproteinase (MMP) after transplantation to chemically injured liver, indicating that WJSC may help to decrease liver collagen and thus may be useful for treating liver fibrosis.

ROCK Inhibitor Y-27632 Increases Thaw-Survival Rates and Preserves Stemness and Differentiation Potential of Human Wharton’s Jelly Stem Cells After Cryopreservation

The ROCK inhibitor Y-27632 inhibits apoptosis and increases proliferation of frozen-thawed cells. We examined the role of Y-27632 on human umbilical cord Wharton's jelly stem cells (hWJSCs) for (1) thaw-survival (2) proliferation and (3) preservation of stemness and differentiation potential after cryopreservation. hWJSCs were allotted to 4 groups [Gp I: Untreated hWJSC controls; Gp II: Pretreatment with Y-27632 (10 μM) for 24 h before freezing; Gp III: Y-27632 (10 μM) in freezing medium and Gp IV: Pretreatment with Y-27632 (10 μM) for 24 h and inclusion in freezing medium]. All groups were frozen using a rapid freezing method and stored at -196°C in liquid nitrogen for 90 days before evaluation for apoptosis, cell proliferation, stemness and differentiation. After thawing, Groups II, III and IV showed improved cell attachment, increased thaw-survival (live/dead cell counts) and increased cell proliferation (Trypan blue and MTT assay) compared to controls. CD marker stemness profiles, morphology and normal karyotypes were maintained in the treatment groups after thawing and there was no obvious evidence of apoptosis (Annexin V-FITC and TUNEL assays). After thawing, qRT-PCR demonstrated up-regulation of the anti-apoptotic BCL2 gene and down-regulation of the pro-apoptotic BAX gene and cell cycle regulators (P53 and P21) in the treatment groups. Treated frozen-thawed hWJSCs from all groups differentiated into a neuronal phenotype (neuronal morphology and expression of GFAP, β-3 tubulin and SOX2). Increased thaw-survival and retention of stemness and differentiation potential in hWJSCs following cryopreservation is useful for their storage in cord blood banks for future regenerative medicine purposes.

Derivation efficiency, cell proliferation, freeze–thaw survival, stem-cell properties and differentiation of human Wharton’s jelly stem cells

Human mesenchymal stem cells (MSC) are non-controversial multipotent stem cells. Their presence in umbilical cord blood (UCB) has been debated in some studies and others report low counts per cord blood unit and poor proliferation rates. On the other hand, Wharton's jelly of human umbilical cords appears to be a rich source of human MSC. This study derived 13 human Wharton's jelly stem cell (WJSC) lines from 13 human umbilical cords (100%) and recovered 4.7 +/- 0.2 x 10(6) live WJSC/cm of cord before culture. Complex culture medium produced greater proliferation rates of the WJSC in culture compared with simple medium. The mean population doubling times were 24.47 +/- 0.33 to 26.25 +/- 0.50 h in complex medium. The stem-cell markers of the WJSC were retained for at least 10 passages in both media. After programmed machine freezing, the thaw-survival rates of WJSC were 85-90% and they could be differentiated into neurons. Given the high derivation efficiency, availability of large numbers of fresh live cells, high expansion capabilities, prolonged maintenance of stem-cell properties and differentiation potential, it is proposed that human WJSC may be frozen at the same time as UCB in cord blood banks for regenerative medicine purposes.

Transdifferentiation potentiality of human Wharton's jelly stem cells towards vascular endothelial cells

Human Wharton's jelly stem cells (HWJSC) emerged as a potential source of viable cells for use in tissue engineering. In this work, we have analyzed the transdifferentiation capabilities of HWJSC towards transdifferentiated endothelial-like cells (Tr-ELC) in order to establish the potential usefulness of these cells in vascular tissue engineering. Our results show that Tr-ELC became more polygonal and less proliferative than HWJSC, resembling the structure and proliferation rate of the endothelial cells. In addition, the markers of mesenchymal undifferentiation CD9, E-cad, PODXL, and SSEA-4 are downregulated in Tr-ELC, suggesting that these cells can be in the process of adult differentiation. Besides, RT-PCR and microarray analyses revealed that some genes with a role in defining the endothelial phenotype and structure are upregulated (VEGF-R1, EDF1, AAMP, CD31, CD34, CDH5, and ICAM2) or downregulated (VEGF) in Tr-ELC, although a number of genes related to relevant endothelial cell functions (CD36, ECE2, VWF, THBD, PGI2, ECE1, and ACE) did not change or were only partially induced. All this implies that HWJSC are able to efficiently transdifferentiate towards Tr-ELC at the phenotypical level following a hierarchical pattern of gene activation, with an earlier induction of morphological and phenotypical genes.

Taking stem cells to the clinic: Major challenges

Stem cell therapy offers tremendous promise in the treatment of many incurable diseases. A variety of stem cell types are being studied but human embryonic stem cells (hESCs) appear to be the most versatile as they are pluripotent and can theoretically differentiate into all the tissues of the human body via the three primordial germ layers and the male and female germ lines. Currently, hESCs have been successfully converted in vitro into functional insulin secreting islets, cardiomyocytes, and neuronal cells and transfer of such cells into diabetic, ischaemic, and parkinsonian animal models respectively have shown successful engraftment. However, hESC-derived tissue application in the human is fraught with the problems of ethics, immunorejection, tumorigenesis from rogue undifferentiated hESCs, and inadequate cell numbers because of long population doubling times in hESCs. Human mesenchymal stem cells (hMSC) though not tumorigenic, also have their limitations of multipotency, immunorejection, and are currently confined to autologous transplantation with the genuine benefits in allogeneic settings not conclusively shown in large controlled human trials. Human Wharton's jelly stem cells (WJSC) from the umbilical cord matrix which are of epiblast origin and containing both hESC and hMSC markers appear to be less troublesome in not being an ethically controversial source, widely multipotent, not tumorigenic, maintain "stemness" for several serial passages and because of short population doubling time can be scaled up in large numbers. This report describes in detail the hurdles all these stem cell types have to overcome before stem cell-based therapy becomes a genuine reality.

Comparative growth behaviour and characterization of stem cells from human Wharton's jelly

Human embryonic stem cells (hESC) face ethical sensitivities and the problem of teratoma formation. Although Wharton's jelly stem cells (WJSC), also of embryonic origin, may not face such ethical concerns, it is not definitely known whether under hESC culture conditions they would be as pluripotent as hESC. WJSC grown on plastic showed two types of morphology (epithelioid and short fibroblastic) in primary culture depending on the culture medium used, and only fibroblastic morphology when passaged. When grown in the presence of hESC medium on mouse feeder cells, they produced atypical colonies containing hESC-like cells with high-nuclear cytoplasmic ratios and prominent nucleoli. They were positive for the hESC markers Tra-1–60, Tra-1–81, SSEA-1, SSEA-4, Oct-4 and alkaline phosphatase, negative for SSEA-3, showed normal karyotypes, developed embryoid body (EB)-like structures, did not produce teratomas in SCID mice and differentiated into neuronal derivatives. They were also positive for the mesenchymal CD markers (CD105, CD90, CD44), negative for CD34 and HLA, and although nine out of 10 embryonic stem cell genomic markers were detectable, these were expressed at low levels. WJSC are thus not as pluripotent as hESC but widely multipotent, and have the advantages of being able to be scaled up easily and not inducing teratomas.