Osteogenic Differentiation of Human Wharton's Jelly Stem Cells on Nanofibrous Substrates In Vitro

Electroconductive gelatin/hyaluronic acid/hydroxyapatite scaffolds for enhanced cell proliferation and osteogenic differentiation in bone tissue engineering

Addressing the challenge of bone tissue regeneration requires creating an optimal microenvironment that promotes both osteogenesis and angiogenesis. Electroconductive scaffolds have emerged as promising solutions for bone regeneration; however, existing conductive polymers often lack biofunctionality and biocompatibility. In this study, we synthesized poly(3,4-ethylenedioxythiophene) nanoparticles (PEDOT NPs) using chemical oxidation polymerization and incorporated them into gelatin/hyaluronic acid/hydroxyapatite (Gel:HA:HAp) scaffolds to develop Gel:HA:HAp:PEDOT-NP scaffolds. Morphological analysis by scanning electron microscopy (SEM) showed a honeycomb-like structure with pores of 228-250 μm in diameter. The addition of the synthesized PEDOT NPs increased the conductive capabilities of the scaffolds to 1 × 10-6 ± 1.3 × 10-7 S/cm. Biological assessment of PEDOT NP scaffolds using human foetal osteoblastic 1.19 cells (hFOB), and human bone marrow-derived mesenchymal stem cells (hBMSCs) revealed enhanced cell proliferation and viability compared to control scaffold without NPs, along with increased osteogenic differentiation, evidenced by higher levels of alkaline phosphatase activity, osteopontin (OPN), alkaline phosphatase (ALP), and osteocalcin (OCN) expression, as observed through immunofluorescence, and enhanced expression of osteogenic-related genes. The conductive scaffold shows interesting mineralization capacity, as shown by Alizarin red and Osteoimage staining. Furthermore, PEDOT-NP scaffolds promoted angiogenesis, as indicated by improved tube formation abilities of human umbilical vein endothelial cells (HUVECs), especially at the higher concentrations of NPs. Overall, our findings demonstrate that the integration of PEDOT NPs scaffold enhances their conductive properties and promotes cell proliferation, osteogenic differentiation, and angiogenesis. Gel:HA:HAp:PEDOT-NP scaffolds exhibit promising potential as efficient biomaterials for bone tissue regeneration, offering a potential engineered platform for clinical applications.

Mesenchymal Stem Cell-Derived Exosomes Mitigate Acute Murine Liver Injury via Ets-1 and Heme Oxygenase-1 Up-regulation

BACKGROUND

Mesenchymal stem cells (MSCs)-derived exosomes have been previously demonstrated to promote tissue regeneration in various animal disease models. This study investigated the protective effect of exosome treatment in carbon tetrachloride (CCl4)-induced acute liver injury and delineated possible underlying mechanism.

METHODS

Exosomes collected from conditioned media of previously characterized human umbilical cord-derived MSCs were intravenously administered into male CD-1 mice with CCl4-induced acute liver injury. Biochemical, histological and molecular parameters were used to evaluate the severity of liver injury. A rat hepatocyte cell line, Clone-9, was used to validate the molecular changes by exosome treatment.

RESULTS

Exosome treatment significantly suppressed plasma levels of AST, ALT, and pro-inflammatory cytokines, including IL-6 and TNF-α, in the mice with CCl4-induced acute liver injury. Histological morphometry revealed a significant reduction in the necropoptic area in the injured livers following exosome therapy. Consistently, western blot analysis indicated marked elevations in hepatic expression of PCNA, c-Met, Ets-1, and HO-1 proteins after exosome treatment. Besides, the phosphorylation level of signaling mediator JNK was significantly increased, and that of p38 was restored by exosome therapy. Immunohistochemistry double staining confirmed nuclear Ets-1 expression and cytoplasmic localization of c-Met and HO-1 proteins. In vitro studies demonstrated that exosome treatment increased the proliferation of Clone-9 hepatocytes and protected them from CCl4-induced cytotoxicity. Kinase inhibition experiment indicated that the exosome-driven hepatoprotection might be mediated through the JNK pathway.

CONCLUSION

Exosome therapy activates the JNK signaling activation pathway as well as up-regulates Ets-1 and HO-1 expression, thereby protecting hepatocytes against hepatotoxin-induced cell death.

Scaffolds from Self-Assembling Tetrapeptides Support 3D Spreading, Osteogenic Differentiation, and Angiogenesis of Mesenchymal Stem Cells

The apparent rise of bone disorders demands advanced treatment protocols involving tissue engineering. Here, we describe self-assembling tetrapeptide scaffolds for the growth and osteogenic differentiation of human mesenchymal stem cells (hMSCs). The rationally designed peptides are synthetic amphiphilic self-assembling peptides composed of four amino acids that are nontoxic. These tetrapeptides can quickly solidify to nanofibrous hydrogels that resemble the extracellular matrix and provide a three-dimensional (3D) environment for cells with suitable mechanical properties. Furthermore, we can easily tune the stiffness of these peptide hydrogels by just increasing the peptide concentration, thus providing a wide range of peptide hydrogels with different stiffnesses for 3D cell culture applications. Since successful bone regeneration requires both osteogenesis and vascularization, our scaffold was found to be able to promote angiogenesis of human umbilical vein endothelial cells (HUVECs) in vitro. The results presented suggest that ultrashort peptide hydrogels are promising candidates for applications in bone tissue engineering.

Expanded Differentiation Capability of Human Wharton's Jelly Stem Cells Toward Pluripotency: A Systematic Review

Human Wharton's jelly stem cells (HWJSC) can be efficiently isolated from the umbilical cord, and numerous reports have demonstrated that these cells can differentiate into several cell lineages. This fact, coupled with the high proliferation potential of HWJSC, makes them a promising source of stem cells for use in tissue engineering and regenerative medicine. However, their real potentiality has not been established to date. In the present study, we carried out a systematic review to determine the multilineage differentiation potential of HWJSC. After a systematic literature search, we selected 32 publications focused on the differentiation potential of these cells. Analysis of these studies showed that HWJSC display expanded differentiation potential toward some cell types corresponding to all three embryonic cell layers (ectodermal, mesodermal, and endodermal), which is consistent with their constitutive expression of key pluripotency markers such as OCT4, SOX2, and NANOG, and the embryonic marker SSEA4. We conclude that HWJSC can be considered cells in an intermediate state between multipotentiality and pluripotentiality, since their proliferation capability is not unlimited and differentiation to all cell types has not been demonstrated thus far. These findings support the clinical use of HWJSC for the treatment of diseases affecting not only mesoderm-type tissues but also other cell lineages. Impact statement Human Wharton's jelly stem cells (HWJSC) are mesenchymal stem cells that are easy to isolate and handle, and that readily proliferate. Their wide range of differentiation capabilities supports the view that these cells can be considered pluripotent. Accordingly, HWJSC are one of the most promising cell sources for clinical applications in advanced therapies.

Histological, immunohistochemical, and genomic evaluation of excisional and diabetic wounds treated with human Wharton's jelly stem cells with and without a nanocarrier

We showed in previous studies that human umbilical cord Wharton's jelly stem cells (hWJSCs) improved the healing rates of excisional and diabetic wounds in the mouse model. As an extension of those studies, we report here the more detailed quantitative histological, immunohistochemical, and genomic evaluation of biopsies from those excisional and diabetic wounds in an attempt to understand the mechanisms of the enhanced wound healing aided by hWJSCs. Bright-field microscopic observations and ImageJ software analysis on histological sections of the excisional and diabetic wound biopsies collected at different time points showed that the thickness of the epidermis and dermis, and positive picrosirius-red stained areas for collagen, were significantly greater in the presence of hWJSCs compared with controls (P < 0.05). Immunohistochemistry of the diabetic wound biopsies showed increased positive staining for the vascular endothelial marker CD31 and cell proliferation marker Ki67 in the presence of hWJSCs and its conditioned medium (hWJSC-CM). Quantitative real-time polymerase chain reaction showed upregulation of groups of genes involved in extracellular matrix regulation, collagen biosynthesis, angiogenesis, antifibrosis, granulation, and immunomodulation in the presence of hWJSCs. Taken together, the results demonstrated that hWJSCs and hWJSC-CM that contains the paracrine secretions of hWJSCs, enhance the healing of excisional and diabetic wounds via re-epithelialization, collagen deposition, angiogenesis, and immunomodulation. The inclusion of an Aloe vera-polycaprolactone (AV/PCL) nanocarrier did not significantly change the effect of the hWJSCs. However, the topical application of an AV/PCL nanocarrier impregnated with hWJSCs is convenient and less invasive than the administration of hWJSC injections into wounds.

Calcium phosphate scaffolds with defined interconnecting channel structure provide a mimetic 3D niche for bone marrow metastasized tumor cell growth

Metastasis of tumor cells in the bone marrow (BM) is a multi-step and highly dynamic process during which cells succumb important phenotypic changes. Behavior of disseminated tumor cells in BM is strictly regulated by three-dimensional (3D) cell-cell and cell-matrix interactions. In this study, we explored whether the β-tricalcium-phosphate (β-TCP) scaffolds with a tailored interconnecting channel structure could enable appropriate 3D mimetic BM microenvironment for the growth of metastatic neuroblastoma cells. The scaffolds provided the mechanical support for human mesenchymal stromal cells (hMSC) allowing them to proliferate, differentiate towards osteoblasts, and produce the deposits of extracellular matrix inside the interconnected channels. The in vitro microenvironment shaped by stromal cells was then tailored by neuroblastoma tumor cells. Immunohistological analyses confirmed the organization of tumor cells into the forms of spheres only when co-cultured with hMSC-derived osteoblasts. The growing rate of tumor cells in 3D conditions was less marked comparing to the one of the cells grown as 2D monolayer as confirmed by decreased Ki-67 expression. Instead, the 3D culturing of neuroblastoma cells inside supportive stroma promoted cell quiescence as sustained by increased p27 level. A balance between cell proliferation, survival, and differentiation was more evident for tumor cells grown inside the 3D scaffolds, thus mirroring better the situation that occurs in vivo where the cells do not follow the exponential growth rate. We conclude that the proposed 3D β-TCP scaffold type provides a mimetic 3D in vitro niche suitable for studying behavior of BM metastasized tumor cells. STATEMENT OF SIGNIFICANCE: Bone marrow (BM) niche is a favorite target of metastatic neuroblastoma cells. To better address the molecular mechanisms that sustain spatiotemporal organization of neuroblastoma cells in the marrow we mimicked the three-dimensional (3D) assembly of stromal and tumor cells inside β-tricalcium-phosphate (β-TCP) scaffolds. β-TCP scaffolds with a tailored interconnecting channel structure provided mechanical support to mesenchymal stromal cells allowing them to differentiate towards osteoblasts and to produce extracellular matrix. A dynamic cell-matrix interplay favored the characteristic rosette-like growth of metastatic neuroblastoma cells and triggered their quiescence. With our study, we confirmed the potential of β-TCP scaffolds with reproduced BM niche as a cost-effective in vitro model for the growth of disseminated tumor cells, and for related biological and pharmacological surveys.

Pelleted Bone Marrow Derived Mesenchymal Stem Cells Are Better Protected from the Deleterious Effects of Arthroscopic Heat Shock

Introduction: The impact of arthroscopic temperature on joint tissues is poorly understood and it is not known how mesenchymal stem cells (MSCs) respond to the effects of heat generated by the device during the process of arthroscopy assisted experimental cell-based therapy. In the present study, we isolated and phenotypically characterized human bone marrow mesenchymal stem cells (hBMMSCs) from osteoarthritis (OA) patients, and evaluated the effect of arthroscopic heat on cells in suspension and pellet cultures.

Methods: Primary cultures of hBMMSCs were isolated from bone marrow aspirates of OA patients and cultured using DMEM supplemented with 10% FBS and characterized for their stemness. hBMMSCs (1 × 10⁶ cells) cultured as single cell suspensions or cell pellets were exposed to an illuminated arthroscope for 10, 20, or 30 min. This was followed by analysis of cellular proliferation and heat shock related gene expression.

Results: hBMMSCs were viable and exhibited population doubling, short spindle morphology, MSC related CD surface markers expression and tri-lineage differentiation into adipocytes, chondrocytes and osteoblasts. Chondrogenic and osteogenic differentiation increased collagen production and alkaline phosphatase activity. Exposure of hBMMSCs to an illuminated arthroscope for 10, 20, or 30 min for 72 h decreased metabolic activity of the cells in suspensions (63.27% at 30 min) and increased metabolic activity in cell pellets (62.86% at 10 min and 68.57% at 20 min). hBMMSCs exposed to 37, 45, and 55°C for 120 s demonstrated significant upregulation of BAX, P53, Cyclin A2, Cyclin E1, TNF-α, and HSP70 in cell suspensions compared to cell pellets.

Conclusions: hBMMSC cell pellets are better protected from temperature alterations compared to cell suspensions. Transplantation of hBMMSCs as pellets rather than as cell suspensions to the cartilage defect site would therefore support their viability and may aid enhanced cartilage regeneration.

Current View on Osteogenic Differentiation Potential of Mesenchymal Stromal Cells Derived from Placental Tissues

Mesenchymal stromal cells (MSC) isolated from human term placental tissues possess unique characteristics, including their peculiar immunomodulatory properties and their multilineage differentiation potential. The osteogenic differentiation capacity of placental MSC has been widely disputed, and continues to be an issue of debate. This review will briefly discuss the different MSC populations which can be obtained from different regions of human term placenta, along with their unique properties, focusing specifically on their osteogenic differentiation potential. We will present the strategies used to enhance osteogenic differentiation potential in vitro, such as through the selection of subpopulations more prone to differentiate, the modification of the components of osteo-inductive medium, and even mechanical stimulation. Accordingly, the applications of three-dimensional environments in vitro and in vivo, such as non-synthetic, polymer-based, and ceramic scaffolds, will also be discussed, along with results obtained from pre-clinical studies of placental MSC for the regeneration of bone defects and treatment of bone-related diseases.

Mesenchymal stem cells in regenerative medicine: Focus on articular cartilage and intervertebral disc regeneration

Musculoskeletal disorders represent a major cause of disability and morbidity globally and result in enormous costs for health and social care systems. Development of cell-based therapies is rapidly proliferating in a number of disease areas, including musculoskeletal disorders. Novel biological therapies that can effectively treat joint and spine degeneration are high priorities in regenerative medicine. Mesenchymal stem cells (MSCs) isolated from bone marrow (BM-MSCs), adipose tissue (AD-MSCs) and umbilical cord (UC-MSCs) show considerable promise for use in cartilage and intervertebral disc (IVD) repair. This review article focuses on stem cell-based therapeutics for cartilage and IVD repair in the context of the rising global burden of musculoskeletal disorders. We discuss the biology MSCs and chondroprogenitor cells and specifically focus on umbilical cord/Wharton's jelly derived MSCs and examine their potential for regenerative applications. We also summarize key components of the molecular machinery and signaling pathways responsible for the control of chondrogenesis and explore biomimetic scaffolds and biomaterials for articular cartilage and IVD regeneration. This review explores the exciting opportunities afforded by MSCs and discusses the challenges associated with cartilage and IVD repair and regeneration. There are still many technical challenges associated with isolating, expanding, differentiating, and pre-conditioning MSCs for subsequent implantation into degenerate joints and the spine. However, the prospect of combining biomaterials and cell-based therapies that incorporate chondrocytes, chondroprogenitors and MSCs leads to the optimistic view that interdisciplinary approaches will lead to significant breakthroughs in regenerating musculoskeletal tissues, such as the joint and the spine in the near future.

Skeletal tissue engineering using mesenchymal or embryonic stem cells: clinical and experimental data

INTRODUCTION

Mesenchymal stem cells (MSCs) can be obtained from a wide variety of tissues for bone tissue engineering such as bone marrow, adipose, birth-associated, peripheral blood, periosteum, dental and muscle. MSCs from human fetal bone marrow and embryonic stem cells (ESCs) are also promising cell sources.

AREAS COVERED

In vitro, in vivo and clinical evidence was collected using MEDLINE® (1950 to January 2014), EMBASE (1980 to January 2014) and Google Scholar (1980 to January 2014) databases.

EXPERT OPINION

Enhanced results have been found when combining bone marrow-derived mesenchymal stem cells (BMMSCs) with recently developed scaffolds such as glass ceramics and starch-based polymeric scaffolds. Preclinical studies investigating adipose tissue-derived stem cells and umbilical cord tissue-derived stem cells suggest that they are likely to become promising alternatives. Stem cells derived from periosteum and dental tissues such as the periodontal ligament have an osteogenic potential similar to BMMSCs. Stem cells from human fetal bone marrow have demonstrated superior proliferation and osteogenic differentiation than perinatal and postnatal tissues. Despite ethical concerns and potential for teratoma formation, developments have also been made for the use of ESCs in terms of culture and ideal scaffold.

Bone and cartilage regeneration with the use of umbilical cord mesenchymal stem cells

INTRODUCTION

The production of functional alternatives to bone autografts and the development new treatment strategies for cartilage defects are great challenges that could be addressed by the field of tissue engineering. Umbilical cord mesenchymal stem cells (MSCs) can be used to produce cost-effective, atraumatic and possibly autologous bone and cartilage grafts.

AREAS COVERED

MSCs can be isolated from umbilical cord Wharton's jelly, perivascular tissue and blood using various techniques. Those cells have been characterized and phenotypic similarities with bone marrow-derived MSCs (BM-MSCs) and embryonic stem cells have been found. Findings on their differentiation into the osteogenic and chondrogenic lineage differ between studies and are not as consistent as for BM-MSCs.

EXPERT OPINION

MSCs from umbilical cords have to be more extensively studied and the mechanisms underlying their differentiation have to be clarified. To date, they seem to be an attractive alternative to BM-MSCs. However, further research with suitable scaffolds and growth factors as well as with novel scaffold fabrication and culture technology should be conducted before they are introduced to clinical practice and replace BM-MSCs.

Positive selection of Wharton's jelly-derived CD105(+) cells by MACS technique and their subsequent cultivation under suspension culture condition: A simple, versatile culturing method to enhance the multipotentiality of mesenchymal stem cells

OBJECTIVE

Wharton's jelly (WJ), an appropriate source of mesenchymal stem cells (MSCs), has been shown to have a wide array of therapeutic applications. However, the WJ-derived MSCs are very heterogeneous and have limited expression of pluripotency markers. Hence, improvement of their culture condition would promote the efficiency of WJ-MSCs. This study aims to employ a simple method of cultivation to obtain WJ-MSCs which express more pluripotency markers.

METHODS

CD105(+) cells were separated by magnetic-associated (activated) cell sorting from umbilical cord mucous tissue. CD105(+) cells were added to Methocult medium diluted in α-minimum essential medium (α-MEM) and seeded in poly(2-hydroxyethyl methacrylate) (poly-HEMA)-coated plates for suspension culture preparation. Differentiation capacity of isolated cells was evaluated in the presence of differentiation-inducing media. The expression of pluripotency markers such as Oct3/4, Nanog, and Sox2 was also analyzed by RT-PCR and western blot techniques. Moreover, immunocytochemistry was performed to detect alpha-smooth muscle actin (antigene) (α-SMA) protein.

RESULTS

WJ-MSCs grew homogeneously and formed colonies when cultured under suspension culture conditions (Non-adhesive WJ-MSCs). They maintained their growth ability in both adherent and suspension cultures for several passages. Non-adhesive WJ-MSCs expressed Oct3/4, Nanog, and Sox2 both at transcriptional and translational levels in comparison to those cultured in conventional adherent cultures. They also expressed α-SMA protein.

DISCUSSION

In this study, we isolated WJ-MSCs using a slightly modified culture condition. Our simple non-genetic method resulted in a homogeneous population of WJ-MSCs, which highly expressed pluripotency markers.

CONCLUSION

In the future, more multipotent WJ-MSCs can be harnessed as a non-embryonic source of MSCs in MSC-based cell therapy.

Comparing the osteogenic potential of canine mesenchymal stem cells derived from adipose tissues, bone marrow, umbilical cord blood, and Wharton's jelly for treating bone defects

Alternative sources of mesenchymal stem cells (MSCs) for replacing bone marrow (BM) have been extensively investigated in the field of bone tissue engineering. The purpose of this study was to compare the osteogenic potential of canine MSCs derived from adipose tissue (AT), BM, umbilical cord blood (UCB), and Wharton's jelly (WJ) using in vitro culture techniques and in vivo orthotopic implantation assays. After canine MSCs were isolated from various tissues, the proliferation and osteogenic potential along with vascular endothelial growth factor (VEGF) production were measured and compared in vitro. For the in vivo assay, MSCs derived from each type of tissue were mixed with β-tricalcium phosphate and implanted into segmental bone defects in dogs. Among the different types of MSCs, AT-MSCs had a higher proliferation potential and BM-MSCs produced the most VEGF. AT-MSCs and UCB-MSCs showed greater in vitro osteogenic potential compared to the other cells. Radiographic and histological analyses showed that all tested MSCs had similar osteogenic capacities, and the level of new bone formation was much higher with implants containing MSCs than cell-free implants. These results indicate that AT-MSCs, UCB-MSCs, and WJ-MSCs can potentially be used in place of BM-MSCs for clinical bone engineering procedures.

Propagation and differentiation of human Wharton's jelly stem cells on three-dimensional nanofibrous scaffolds

Stem cells isolated from the Wharton's jelly of the human umbilical cord (hWJSCs) are unique compared to other stem cell types as they lie in between embryonic stem cells (ESCs) and adult mesenchymal stem cells (MSCs) on the developmental map and share stemness markers of ESCs and MSCs. Yet, they do not induce tumorigenesis and are hypoimmunogenic and proliferative and fresh cell numbers can be harvested painlessly in abundance from discarded umbilical cords. Additionally, they secrete important soluble bioactive molecules from the interleukin and cell adhesion family, hyaluronic acid, collagen, glycosoaminoglycans, and chondroitin sulfate. Many of these molecules are involved in bone, cartilage, and joint repair. It has also been shown that hWJSCs attach, proliferate, and differentiate efficiently in the stem cell niches of three-dimensional matrices, particularly nanofibrous scaffolds. Thus, tissue constructs made up of hWJSCs and biodegradable nanofibrous scaffolds will facilitate clinical translation and improved functional outcome for arthritis, bone, and cartilage diseases. When applied in vivo, the hWJSCs from the tissue construct may improve repair either by differentiating into new chondrocytes or osteocytes and/or release of important factors that favor repair through paracrine functions. The nanofibrous scaffold is expected to provide the architecture and niches for the hWJSCs to perform and will later biodegrade encouraging engraftment. This chapter provides a step-by-step protocol for the preparation of such tissue constructs involving hWJSCs and nanofibrous scaffolds. The methodology also includes the targeted in vitro differentiation of the hWJSCs to osteogenic and chondrogenic lineages when attached to the nanofibrous scaffolds.

Human umbilical cord Wharton's jelly mesenchymal stem cells do not transform to tumor-associated fibroblasts in the presence of breast and ovarian cancer cells unlike bone marrow mesenchymal stem cells

Human bone marrow mesenchymal stem cells (hBMMSCs) were shown to transform into tumor-associated fibroblasts (TAFs) when in the vicinity of breast cancer tumors and played an important role in tumor enhancement and metastasis. In early human development MSCs migrating from the yolk sac and aorta-gonad-mesonephros (AGM) via the umbilical cord to the placenta and back to the fetal bone marrow were shown to get trapped in the gelatinous Wharton's jelly of the umbilical cord. The common origin of the Wharton's jelly MSCs and the finally homed hBMMSCs prompted us to evaluate whether hWJSCs are also involved in TAF transformation. hWJSCs and hBMMSCs were grown in the presence of breast and ovarian cancer cell conditioned medium (MDA-TCM, TOV-TCM) for 30 days. No changes were observed in the hWJSCs but the hBMMSCs transformed from short to thin long fibroblasts, their proliferation rates increased and CD marker expression decreased. The transformed hBMMSCs showed positive staining for the tumor-associated markers FSP, VEGF, EGF, and Tn-C. Real-time PCR and multiplex luminex bead analysis showed upregulation of TAF-related genes (FSP, FAP, Tn-C, Tsp-1, EGF, bFGF, IL-6, α-SMA, VEGF, and TGF-β) for hBMMSCs with low expression for hWJSCs. The luciferase assay showed that hWJSCs previously exposed to MDA-TCM or TOV-TCM had no stimulatory growth effect on luciferase-tagged MDA or TOV cells unlike hBMMSCs. The results confirmed that hWJSCs do not transform to the TAF phenotype and may therefore not be associated with enhanced growth of solid tumors making them a safe MSC for cell based therapies.

Human umbilical cord Wharton's jelly stem cells undergo enhanced chondrogenic differentiation when grown on nanofibrous scaffolds and in a sequential two-stage culture medium environment

The current treatments used for osteoarthritis from cartilage damage have their disadvantages of donor site morbidity, complicated surgical interventions and risks of infection and graft rejection. Recent advances in tissue engineering have offered much promise in cartilage repair but the best cell source and in vitro system have not as yet been optimised. Human bone marrow mesenchymal stem cells (hBMSCs) have thus far been the cell of choice. However, we derived a unique stem cell from the human umbilical cord Wharton's jelly (hWJSC) that has properties superior to hBMSCs in terms of ready availability, prolonged stemness characteristics in vitro, high proliferation rates, wide multipotency, non-tumorigenicity and tolerance in allogeneic transplantation. We observed enhanced cell attachment, cell proliferation and chondrogenesis of hWJSCs over hBMSCs when grown on PCL/Collagen nanoscaffolds in the presence of a two-stage sequential complex/chondrogenic medium for 21 days. Improvement of these three parameters were confirmed via inverted optics, field emission scanning electron microscopy (FESEM), MTT assay, pellet diameters, Alcian blue histology and staining, glycosaminglycans (GAG) and hyaluronic acid production and expression of key chondrogenic genes (SOX9, Collagen type II, COMP, FMOD) using immunohistochemistry and real-time polymerase chain reaction (qRT-PCR). In separate experiments we demonstrated that the 16 ng/ml of basic fibroblast growth factor (bFGF) present in the complex medium may have contributed to driving chondrogenesis. We conclude that hWJSCs are an attractive stem cell source for inducing chondrogenesis in vitro when grown on nanoscaffolds and exposed sequentially first to complex medium and then followed by chondrogenic medium.

Human umbilical cord Wharton's jelly stem cell (hWJSC) extracts inhibit cancer cell growth in vitro

Umbilical cord mesenchymal stem cells (MSCs) have been shown to inhibit breast cancer cell growth but it is not known whether this effect is specific to only breast cancer cells. We compared the effects of human Wharton's jelly stem cell (hWJSC) extracts [conditioned medium (hWJSC-CM) and cell lysate (hWJSC-CL)] on breast adenocarcinoma (MDA-MB-231), ovarian carcinoma (TOV-112D), and osteosarcoma (MG-63) cells. The cells were treated with either hWJSC-CM (50%) or hWJSC-CL (15 µg/ml) for 48-72 h and changes in cell morphology, proliferation, cycle, gene expression, migration, and cell death studied. All three cancer cell lines showed cell shrinkage, blebbing, and vacuolations with hWJSC-CL and hWJSC-CM compared to controls. MTT and BrdU assays showed inhibition of cell growth by 2-6% and 30-60%, while Transwell migration assay showed inhibition by 20-26% and 31-46% for hWJSC-CM and hWJSC-CL, respectively, for all three cancer cell lines. Cell cycle assays showed increases in sub-G1 and G2/M phases for all three cancer cell lines suggestive of apoptosis and metaphase arrest. AnnexinV-FITC and TUNEL positive cells seen in TOV-112D and MDA-MB-231 suggested that inhibition was via apoptosis while the presence of anti-BECLIN1 and anti-LC3B antibodies seen with MG-63 indicated autophagy. Upregulation of pro-apoptotic BAX and downregulation of anti-apoptotic BCL2 and SURVIVIN genes were observed in all three cancer cell lines and additionally the autophagy genes (ATG5, ATG7, and BECLIN1) were upregulated in MG-63 cells. hWJSCs possess tumor inhibitory properties that are not specific to breast cancer cells alone and these effects are mediated via agents in its extracts.

Extra-embryonic human Wharton's jelly stem cells do not induce tumorigenesis, unlike human embryonic stem cells

Tumorigenesis is the major obstacle of tissues derived from human embryonic stem cells (ESC) and human induced pluripotent stem cell (IPSC) for transplantation therapy. This prompted a search for other sources of ESC. This study isolated and characterized stem cells from the extra-embryonic human umbilical cord Wharton's jelly (WJSC). These cells are non-controversial, available in abundance, proliferative, multipotent and hypoimmunogenic. However, their tumorigenic potential has not been properly addressed. Their tumour-producing capabilities were compared with human ESC using the immunodeficient mouse model. Unlabelled human ESC+matrigel (2×10(6)cells/site), labelled human WJSC (red fluorescent protein; 5×10(6)cells/site) and unlabelled human WJSC+matrigel (5×10(6)cells/site) were injected via three routes (s.c., i.m. and i.p.). Animals that received human ESC+matrigel developed teratomas in 6 weeks (s.c. 85%; i.m. 75%; i.p. 100%) that contained tissues of ectoderm, mesoderm and endoderm. No animal that received human WJSC developed tumours or inflammatory reactions at the injection sites when maintained for a prolonged period (20 weeks). Human WJSC produced increases in anti-inflammatory cytokines in contrast to human ESC, which increased pro-inflammatory cytokines. Human WJSC, being hypoimmunogenic and non-tumorigenic, have the potential for safe cell-based therapies.

Collagen-calcium phosphate cement scaffolds seeded with umbilical cord stem cells for bone tissue engineering

Human umbilical cord mesenchymal stem cells (hUCMSCs) avoid the invasive procedure required to harvest bone marrow MSCs. The addition of collagen fibers into self-setting calcium phosphate cement (CPC) may increase the scaffold strength, and enhance cell attachment and differentiation. The objectives of this study were to develop a novel class of collagen-CPC composite scaffolds, and to investigate hUCMSC attachment, proliferation, and osteogenic differentiation on collagen-CPC scaffolds for the first time. Collagen fibers in CPC improved the load-bearing capability. Flow cytometry showed that the hUCMSCs expressed cell surface markers characteristic of MSCs, and were negative for hematopoietic and endothelial cell markers. hUCMSCs proliferated rapidly in all CPC composite scaffolds, with cell number increasing by sevenfold in 8 days. Cellular function was enhanced with collagen fibers in CPC scaffolds. Cell density increased from (645±60) cells/mm(2) on CPC with 0% collagen, to (1056±65) cells/mm(2) on CPC with 8% collagen (p<0.05). The actin stress fibers inside the hUCMSCs were stained, and the fluorescence intensity was doubled when the collagen in CPC was increased by 0% to 8%. RT-PCR showed that hUCMSCs on CPC with collagen had higher osteogenic expression than those on CPC without collagen. Alizarin Red S staining revealed a great increase in mineralization by hUCMSCs on CPC with collagen than that without collagen. In conclusion, hUCMSCs showed excellent proliferation, differentiation, and synthesis of bone minerals in collagen-CPC composite scaffolds for the first time. The novel hUCMSC-seeded collagen-CPC construct with superior cell function and load-bearing capability is promising to enhance bone regeneration in a wide range of orthopedic and craniofacial applications.

Musculoskeletal tissue engineering with human umbilical cord mesenchymal stromal cells

Multipotent mesenchymal stromal cells (MSCs) hold tremendous promise for tissue engineering and regenerative medicine, yet with so many sources of MSCs, what are the primary criteria for selecting leading candidates? Ideally, the cells will be multipotent, inexpensive, lack donor site morbidity, donor materials should be readily available in large numbers, immunocompatible, politically benign and expandable in vitro for several passages. Bone marrow MSCs do not meet all of these criteria and neither do embryonic stem cells. However, a promising new cell source is emerging in tissue engineering that appears to meet these criteria: MSCs derived from Wharton's jelly of umbilical cord MSCs. Exposed to appropriate conditions, umbilical cord MSCs can differentiate in vitro along several cell lineages such as the chondrocyte, osteoblast, adipocyte, myocyte, neuronal, pancreatic or hepatocyte lineages. In animal models, umbilical cord MSCs have demonstrated in vivo differentiation ability and promising immunocompatibility with host organs/tissues, even in xenotransplantation. In this article, we address their cellular characteristics, multipotent differentiation ability and potential for tissue engineering with an emphasis on musculoskeletal tissue engineering.