Therapeutic potentials of mesenchymal stem cells derived from human umbilical cord

Low oxygen atmosphere facilitates proliferation and maintains undifferentiated state of umbilical cord mesenchymal stem cells in an hypoxia inducible factor-dependent manner

BACKGROUND AIMS

As we approach the era of mesenchymal stem cell (MSC) application in the medical clinic, the standarization of their culture conditions are of the particular importance. We re-evaluated the influences of oxygens concentration on proliferation, stemness and differentiation of human umbilical cord Wharton Jelly-derived MSCs (WJ-MSCs).

METHODS

Primary cultures growing in 21% oxygen were either transferred into 5% O2 or continued to grow under standard 21% oxygen conditions. Cell expansion was estimated by WST1/enzyme-linked immunosorbent assay or cell counting. After 2 or 4 weeks of culture, cell phenotypes were evaluated using microscopic, immunocytochemical, fluorescence-activated cell-sorting and molecular methods. Genes and proteins typical of mesenchymal cells, committed neural cells or more primitive stem/progenitors (Oct4A, Nanog, Rex1, Sox2) and hypoxia inducible factor (HIF)-1α-3α were evaluated.

RESULTS

Lowering O2 concentration from 21% to the physiologically relevant 5% level substantially affected cell characteristics, with induction of stemness-related-transcription-factor and stimulation of cell proliferative capacity, with increased colony-forming unit fibroblasts (CFU-F) centers exerting OCT4A, NANOG and HIF-1α and HIF-2α immunoreactivity. Moreover, the spontaneous and time-dependent ability of WJ-MSCs to differentiate into neural lineage under 21% O2 culture was blocked in the reduced oxygen condition. Importantly, treatment with trichostatin A (TSA, a histone deacetylase inhibitor) suppressed HIF-1α and HIF-2α expression, in addition to blockading the cellular effects of reduced oxygen concentration.

CONCLUSIONS

A physiologically relevant microenvironment of 5% O2 rejuvenates WJ-MSC culture toward less-differentiated, more primitive and faster-growing phenotypes with involvement of HIF-1α and HIF-2α-mediated and TSA-sensitive chromatin modification mechanisms. These observations add to the understanding of MSC responses to defined culture conditions, which is the most critical issue for adult stem cells translational applications.

Infusion of human umbilical cord‑derived mesenchymal stem cells effectively relieves liver cirrhosis in DEN‑induced rats

Cirrhosis is the long‑term outcome of chronic hepatic injury and no effective therapy is currently available for this disease. Mesenchymal stromal cells (MSCs) are multipotent cells that are easily acquired and amplified, and may be potential candidates for cell therapy against cirrhosis. This study aimed to determine the therapeutic effects of human umbilical cord‑derived MSCs (hUCMSCs) for the treatment of liver cirrhosis and identify an effective method for engrafting MSCs. The model of liver cirrhosis was established by induction of diethylnitrosamine (DEN) in rats. The isolated hUCMSCs were identified by morphology, flow cytometry and multilineage differentiation; they were injected into the vein of DEN‑induced rats at varied cell doses and infusion times. Biochemical analyses of the serum and histopathological analysis of the liver tissues were performed to evaluate the therapeutic effects of hUCMSCs in all treatment groups. The results indicated that isolated hUCMSCs were capable of self‑replication and differentiated into multiple lineages, including osteoblast‑, adipocyte‑ and hepatocyte‑like cells. Compared with the control group, administration of hUCMSCs at different cell doses and infusion times relieved DEN‑induced cirrhosis to varying degrees. The therapeutic effects of hUCMSCs on liver cirrhosis gradually improved with increased cell dose and infusion times. The improvement of cirrhosis was due to the capacity of hUCMSCs to breakdown collagen fibers in the liver. It was demonstrated that infusion of hUCMSCs effectively relieved liver cirrhosis by facilitating the breakdown of collagen fibers in a dose‑dependent manner and multiple infusions caused a relatively greater improvement in cirrhosis compared with a single infusion of hUCMSCs.

Engineering of pre-vascularized urethral patch with muscle flaps and hypoxia-activated hUCMSCs improves its therapeutic outcome

Tissue engineering has brought new hopes for urethral reconstruction. However, the absence of pre-vascularization and the subsequent degradation of materials often lead to the failure of in vivo application. In this study, with the assistance of hypoxia-activated human umbilical cord mesenchymal stem cells (hUCMSCs), pedicled muscle flaps were used as materials and pre-incubated in ventral penile subcutaneous cavity of rabbit for 3 weeks to prepare a pre-vascularized urethral construct. We found that small vessels and muscle fibres were scattered in the construct after 3 weeks' pre-incubation. The construct presented a fibrous reticular structure, which was similar to that of the corpus spongiosum under microscope examination. The produced constructs were then used as a patch graft for reconstruction of the defective rabbit urethra (experimental group), natural muscular patch was used as control (control group). Twelve weeks after the reconstructive surgery, urethrography and urethroscope inspections showed wide calibres of the reconstructed urethra in the experimental group. Histopathological studies revealed that fibrous connective tissues and abundant muscle fibres constituted the main body of the patch-grafted urethra. In contrast, in the control group, only adipose tissue was found in the stenosis-reconstructed urethra, replacing the originally grafted muscular tissue. To our knowledge, this is the first report that successfully constructed a pre-vascularized urethral construct by using hypoxia-activated hUCMSC and pedicled muscle flaps. More importantly, the pre-vascularized construct showed a good performance in urethral reconstruction when applied in vivo. The study provided a novel strategy for tissue engineering of pre-vascularized urethral construct for the defective urethra, representing a further advancement in urethral reconstruction.

Umbilical cord mesenchymal stem cells labeled with multimodal iron oxide nanoparticles with fluorescent and magnetic properties: application for in vivo cell tracking

Here we describe multimodal iron oxide nanoparticles conjugated to Rhodamine-B (MION-Rh), their stability in culture medium, and subsequent validation of an in vitro protocol to label mesenchymal stem cells from umbilical cord blood (UC-MSC) with MION-Rh. These cells showed robust labeling in vitro without impairment of their functional properties, the viability of which were evaluated by proliferation kinetic and ultrastructural analyzes. Thus, labeled cells were infused into striatum of adult male rats of animal model that mimic late onset of Parkinson’s disease and, after 15 days, it was observed that cells migrated along the medial forebrain bundle to the substantia nigra as hypointense spots in T2 magnetic resonance imaging. These data were supported by short-term magnetic resonance imaging. Studies were performed in vivo, which showed that about 5 × 10⁵ cells could be efficiently detected in the short term following infusion. Our results indicate that these labeled cells can be efficiently tracked in a neurodegenerative disease model.

Mesenchymal stem cells and their subpopulation, pluripotent muse cells, in basic research and regenerative medicine

Mesenchymal stem cells (MSCs) have gained a great deal of attention for regenerative medicine because they can be obtained from easy accessible mesenchymal tissues, such as bone marrow, adipose tissue, and the umbilical cord, and have trophic and immunosuppressive effects to protect tissues. The most outstanding property of MSCs is their potential for differentiation into cells of all three germ layers. MSCs belong to the mesodermal lineage, but they are known to cross boundaries from mesodermal to ectodermal and endodermal lineages, and differentiate into a variety of cell types both in vitro and in vivo. Such behavior is exceptional for tissue stem cells. As observed with hematopoietic and neural stem cells, tissue stem cells usually generate cells that belong to the tissue in which they reside, and do not show triploblastic differentiation. However, the scientific basis for the broad multipotent differentiation of MSCs still remains an enigma. This review summarizes the properties of MSCs from representative mesenchymal tissues, including bone marrow, adipose tissue, and the umbilical cord, to demonstrate their similarities and differences. Finally, we introduce a novel type of pluripotent stem cell, multilineage-differentiating stress-enduring (Muse) cells, a small subpopulation of MSCs, which can explain the broad spectrum of differentiation ability in MSCs.

Human umbilical mesenchymal stem cells-seeded bladder acellular matrix grafts for reconstruction of bladder defects in a canine model

Background

The goal of this study was to explore the feasibility of utilizing human umbilical mesenchymal stem cells (HUMSCs)-seeded Bladder acellular matrix graft (BAMG) for bladder reconstruction in a canine model.

Methodology/Principal Findings

HUMSCs were isolated from newborn umbilical cords and identified by flow cytometry. Partial cystectomy was performed in the experimental and control group. Bladder defects were repaired with HUMSCs-BAMG in the experimental group and repaired with unseeded-BAMG in control group. The implanted grafts were harvested after surgery. H&E and immunohistochemistry staining were performed to evaluate the regeneration of the bladder defect. Primary cultured HUMSCs displayed typical fibroblast morphology with spindle-shaped. Flow cytometry indicated that these cells were positive for CD105 (97.3%) and CD44 (99%), but negative for CD34 (2.8%), CD31 (2.1%), and CD45 (1.7%). Immunohistochemistry staining showed that a multilayered urothelium and well-developed smooth muscle were observed at 12 weeks in experiment group. In contrast, multilayered urothelial tissues were also observed at 12 weeks in group B, but well-developed smooth muscle bundles were observed.

Conclusions/Significance

Our preliminary results demonstrate that UMSC-seeded BAMGs are superior to unseeded BAMGs to promote the regeneration of bladder defects. Our findings indicated that HUMSCs may be a potential cell source for bladder tissue engineering.

Light-controlled astrocytes promote human mesenchymal stem cells toward neuronal differentiation and improve the neurological deficit in stroke rats

Astrocytes are key components of the central nervous system (CNS) and release factors to support neural stem cell proliferation, differentiation, and migration. Adenosine 5'-triphosphate (ATP) is one of the key factors released upon activation of astrocytes that regulates the neural stem cell's function. However, it is not clear whether ATP derived from the depolarized astrocytes plays a vital role in promoting the neuronal differentiation of mesenchymal stem cells (MSCs) in vitro and in vivo. Herein, for the first time, we co-cultured MSCs with light-stimulated-channelrhodopsin-2 (ChR2)-astrocytes, and observed that the neuronal differentiation of MSCs was enhanced by expressing more neuronal markers, Tuj1 and NeuN. The ChR2-astrocyte-conditioned medium also stimulated MSCs differentiating into neuronal lineage cells by expressing more Tuj1 and Pax6, which was blocked by the P2X receptor antagonist, TNP-ATP. Then we found that light-depolarization of astrocytes significantly increased ATP accumulation in their bathing medium without impairing the cell membrane. We further found that ATP up-regulated the Tuj1, Pax6, FZD8 and β-catenin mRNA levels of MSCs, which could be reversed by application of TNP-ATP. Together these in vitro data provided convergent evidence that ATP from light-depolarized-astrocytes activated the wnt/β-catenin signaling of MSCs through binding to the P2X receptors, and promoted the neuronal differentiation of MSCs. Finally but importantly, our study also demonstrated in stroke rats that light-controlled astrocytes stimulated endogenous ATP release into the ischemic area to influence the transplanted MSCs, resulting in promoting the MSCs towards neuronal differentiation and improvements of neurological deficit.

Umbilical cord mesenchymal stem cell transplantation significantly improves neurological function in patients with sequelae of traumatic brain injury

The aim of this study was to investigate the effects of transplantation with umbilical cord mesenchymal stem cells in patients with sequelae of traumatic brain injury (TBI). The study hypothesis was that umbilical cord mesenchymal stem cell transplantation could safely and effectively improve neurological function in patients with sequelae of traumatic brain injury. Forty patients with sequelae of TBI were randomly assigned to the stem cell treatment group or the control group. The patients in the stem cell treatment group underwent 4 stem cell transplantations via lumbar puncture. All patients of the group were also evaluated using Fugl-Meyer Assessments (FMA) and Functional Independence Measures (FIM) before and at 6 months after the stem cell transplantation. The patients in the control group did not receive any medical treatment (i.e., neither surgery nor medical intervention), and their FMA and FIM scores were determined on the day of the visit to the clinic and at 6 months after that clinical observation. The FMA results demonstrated an improvement in upper extremity motor sub-score, lower extremity motor sub-score, sensation sub-score and balance sub-score in the stem cell transplantation group at 6 months after the transplantation (P<0.05). The FIM results also exhibited significant improvement (P<0.05) in the patient self-care sub-score, sphincter control sub-score, mobility sub-score, locomotion sub-score, communication sub-score and social cognition sub-score. The control group exhibited no improvements after 6 months (P>0.05). All in all, the study results confirmed that the umbilical cord mesenchymal stem cell transplantation improved the neurological function and self-care in patients with TBI sequels. Umbilical cord mesenchymal stem cell transplantation may be a potential treatment for patients with sequelae of TBI. Further research, including a multicenter and large sample size prospective randomized clinical trial, will be required to define definitively the role of umbilical cord mesenchymal stem cell transplantation on sequelae of TBI.

Alternative xeno-free biomaterials derived from human umbilical cord for the self-renewal ex-vivo expansion of mesenchymal stem cells

Mesenchymal stem cells (MSCs) are attractive candidates for novel cell-therapy applications. However, the in vitro expansion of MSCs typically depends on the presence of fetal bovine serum (FBS) and coating materials derived from animal sources, which may cause contamination in clinical applications. In this study, we investigated whether human umbilical cord extract (UCE) could serve as a serum replacement and whether collagen purified from umbilical cord (UC-collagen) could act as an extracellular matrix (ECM) for the in vitro culture of MSCs derived from human UC (UC-MSCs). A total of 5.61 ± 0.54 mg UCE and 18.41 ± 2.42 mg collagen were extracted, and 1.3 ± 0.2 × 10⁵ cells were isolated from 1 g of UC, as determined by the expression of typical MSC surface markers. Importantly, the proliferation and stemness of the UC-MSCs cultured with the UCE media were similar to those cultured under FBS conditions on UC-collagen-treated plates for eight passages. Based on these results, we suggest that UCs, which are discarded as medical waste, represent a viable alternative source of xeno-free biomaterials to replace animal-derived serum and ECM materials for the cultivation of various cell types, including UC-MSCs, adipose tissue-derived MSCs, bone marrow-derived MSCs, and fibroblasts. This innovative xeno-free MSCs culture system can overcome many of the problems associated with immunogenicity, and it will further contribute to the enhancement of treatment efficiency.

Human mesenchymal stem cells: a bank perspective on the isolation, characterization and potential of alternative sources for the regeneration of musculoskeletal tissues

The continuous discovery of human mesenchymal stem cells (hMSCs) in different tissues is stirring up a tremendous interest as a cell source for regenerative medicine therapies. Historically, hMSCs have been always considered a sub-population of mononuclear cells present in the bone marrow (BM). Although BM-hMSCs are still nowadays considered as the most promising mesenchymal stem cell population to reach the clinics due to their capacity to differentiate into multiple tissues, hMSCs derived from other adult and fetal tissues have also demonstrated to possess similar differentiation capacities. Furthermore, different reports have highlighted a higher recurrence of hMSCs in some of these tissues as compared to BM. This offer a fascinating panorama for cell banking, since the creation of a stem cell factory could be envisioned where hMSCs are stocked and used for ad hoc clinical applications. In this review, we summarize the main findings and state of the art in hMSCs isolation, characterization, and differentiation from alternative tissue sources and we attempt to compare their potency for musculoskeletal regeneration.

Immune-related antigens, surface molecules and regulatory factors in human-derived mesenchymal stromal cells: the expression and impact of inflammatory priming

Based on their ability to regulate immune responses, MSCs are considered to be potential candidates for managing immune-mediated diseases in the context of immune therapy. AT and WJ are considered valuable alternatives for BM as a source of MSCs. A detailed and comparative characterization of the immunological profile of MSCs derived from different sources, as well as an understanding of their responsiveness under certain circumstances, such as inflammation, is required to facilitate efficient and well-designed clinical studies. Flow cytometric analyses revealed clear differences among MSC types concerning the expression of the endothelial (e.g., CD31, CD34, CD144 and CD309) and stromal (e.g., CD90 and CD105) associated markers. Regardless of their source, MSCs did not express any of the known hematopoietic markers. All MSCs were uniformly positive for HLA-ABC and lacked the expression of HLA-DR and the co-stimulatory molecules (e.g., CD40, CD80, CD86, CD134 and CD252) required for full T-cell activation. Tissue-specific MSCs presented a modulated expression of cell adhesion molecules that is important for their cellular interactions. MSCs exhibited several surface (e.g., CD73, HLA-G, HO-1 and CD274) and soluble (e.g., HGF, PGE2 and IGFBP-3) immunoregulatory molecules. According to these immunological profiles, the present work provides evidence that the source from which MSCs are derived is important for the design of MSC-based immunointervention approaches. In light of these observations, we may suggest that WJ-MSCs appear to be the most attractive cell population to use in immune cellular therapy when immunosuppressive action is required.

Stem cell therapy to cure type 1 diabetes: from hype to hope

Type 1 diabetes mellitus (T1D) is a chronic, multifactorial autoimmune disease that involves the progressive destruction of pancreatic β-cells, ultimately resulting in the loss of insulin production and secretion. The goal of clinical intervention is to prevent or arrest the onset and progression of autoimmunity, reverse β-cell destruction, and restore glycometabolic and immune homeostasis. Despite promising outcomes observed with islet transplantation and advancements in immunomodulatory therapies, the need for an effective cell replacement strategy for curing T1D still persists. Stem cell therapy offers a solution to the cited challenges of islet transplantation. While the regenerative potential of stem cells can be harnessed to make available a self-replenishing supply of glucose-responsive insulin-producing cells, their immunomodulatory properties may potentially be used to prevent, arrest, or reverse autoimmunity, ameliorate innate/alloimmune graft rejection, and prevent recurrence of the disease. Herein, we discuss the therapeutic potential of stem cells derived from a variety of sources for the cure of T1D, for example, embryonic stem cells, induced pluripotent stem cells, bone marrow-derived hematopoietic stem cells, and multipotent mesenchymal stromal cells derived from bone marrow, umbilical cord blood, and adipose tissue. The benefits of combinatorial approaches designed to ensure the successful clinical translation of stem cell therapeutic strategies, such as approaches combining effective stem cell strategies with islet transplantation, immunomodulatory drug regimens, and/or novel bioengineering techniques, are also discussed. To conclude, the application of stem cell therapy in the cure for T1D appears extremely promising.

Human mesenchymal stem cells from the umbilical cord matrix: successful isolation and ex vivo expansion using serum-/xeno-free culture media

Mesenchymal stem cells (MSC) could potentially be applied in therapeutic settings due to their multilineage differentiation ability, immunomodulatory properties, as well as their trophic activity. The umbilical cord matrix (UCM) represents a promising source of MSC for biomedical applications. The number of cells isloated per umbilical cord (UC) unit is limited and ex vivo expansion is imperative in order to reach clinically meaningful cell numbers. The limitations of poorly defined reagents (e.g. fetal bovine serum, which is commonly used as a supplement for human MSC expansion) make the use of serum-/xeno-free conditions mandatory. We demonstrated the feasibility of isolating UCM-MSC by plastic adherence using serum-/xeno-free culture medium following enzymatic digestion of UCs, with a 100% success rate. 2.6 ± 0.21 × 10(5) cells were isolated per UC unit, of which 1.9 ± 0.21 × 10(5) were MSC-like cells expressing CD73, CD90, and CD105. When compared to adult sources (bone marrow-derived MSC and adipose-derived stem/stromal cells), UCM-MSC displayed a similar immunophenotype and similar multilineage differentiation ability, while demonstrating a higher expansion potential (average fold increase of 7.4 for serum-containing culture medium and 11.0 for xeno-free culture medium (P3-P6)). The isolation and expansion of UCM-MSC under defined serum-/xeno-free conditions contributes to safer and more effective MSC cellular products, boosting the usefulness of MSC in cellular therapy and tissue engineering.

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.

Tracking of In-111-labeled human umbilical tissue-derived cells (hUTC) in a rat model of cerebral ischemia using SPECT imaging

BACKGROUND

In order to increase understanding of how infused cells work, it becomes important to track their initial movement, localization, and engraftment efficiency following transplantation. However, the available in vivo cell tracking techniques are suboptimal. The study objective was to determine the biodistribution of intravenously administered Indium-111 (In-111) oxine labeled human umbilical tissue-derived cells (hUTC) in a rat model of transient middle cerebral occlusion (tMCAo) using single photon emission computed tomography (SPECT).

METHODS

Rats received 3 million In-111 labeled hUTC (i.v.) 48 hrs after tMCAo. Following the administration of either hUTC or equivalent dose of In-111-oxine (18.5 MBq), animals underwent SPECT imaging on days 0, 1, and 3. Radioactivity in various organs as well as in the stroke area and contralateral hemisphere was determined, decay corrected and normalized to the total (whole body including head) radioactivity on day 0. Immunohistochemical analysis was also performed to confirm the beneficial effects of hUTC on vascular and synaptic density, and apoptosis.

RESULTS

Most of the radioactivity (43.36±23.07% on day 0) trafficked to the lungs immediately following IV administration of In-111 labeled hUTC (day 0) and decreased drastically to 8.81±7.75 and 4.01±4.52% on days 1 and 3 post-injection, respectively. In contrast, radioactivity measured in the lung of animals that received In-111-oxine alone remained relatively unchanged from day 0 to day 1 (18.38±5.45% at day 0 to 12.59±5.94%) and decreased to 8.34±4.25% on day 3. Significantly higher radioactivity was observed in stroke areas of animals that received In-111 labeled hUTC indicating the presence of cells at the site of injury representing approximately 1% of total administered dose. In addition, there was significant increase in vascular and synaptophysin immunoreactivity in stroke areas of rats that received In-111 labeled hUTC.

CONCLUSIONS

The present studies showed the tracking of In-111 labeled hUTC to the sites of stroke in a rat model of tMCAo using SPECT. Animals treated with In-111 labeled hUTC showed histological improvements, with higher vascular and synaptic densities observed in the ischemic boundary zone (IBZ).

Intravenous administration of human umbilical tissue-derived cells improves neurological function in aged rats after embolic stroke

Intravenous administration of human umbilical tissue-derived cells (hUTC) improves neurological function in young adult rats after stroke. However, stroke is a major cause of death and disability in the aged population, with the majority of stroke patients 65 years and older. The present study investigated the effect of hUTC on aged rats after embolic stroke. Rats at the age of 18-20 months were subjected to embolic middle cerebral artery (MCA) occlusion. Two groups of eight animals each were compared. The investigational group was injected intravenously with 1×10(7) cells/kg in serum-free culture medium (vehicle) 24 h after stroke onset, and the control group was treated with vehicle only at the same time poststroke. Intravenous administration of hUTC significantly improved neurological functional recovery without reducing infarct volume compared to vehicle-treated aged rats. Additionally, hUTC treatment significantly enhanced synaptogenesis and vessel density in the ischemic boundary zone (IBZ). Moreover, hUTC treatment resulted in a trend toward increased progenitor cell proliferation in the subventricular zone (SVZ) compared to vehicle-treated aged rats. Intravenous administration of hUTC improved functional recovery in aged rats after stroke. The enhancement of synaptogenesis and vessel density may contribute to the beneficial effects of hUTC in the treatment of stroke in the aged animal.

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.

Bioceramic-mediated trophic factor secretion by mesenchymal stem cells enhances in vitro endothelial cell persistence and in vivo angiogenesis

Mesenchymal stem cells (MSCs) seeded in composite implants formed of hydroxyapatite (HA) and poly (lactide-co-glycolide) (PLG) exhibit increased osteogenesis and enhanced angiogenic potential. Endothelial colony-forming cells (ECFCs) can participate in de novo vessel formation when implanted in vivo. The aim of this study was to determine the capacity of HA-PLG composites to cotransplant MSCs and ECFCs, with the goal of accelerating vascularization and resultant bone formation. The incorporation of HA into PLG scaffolds improved the efficiency of cell seeding and ECFC survival in vitro. We observed increases in mRNA expression and secretion of potent angiogenic factors by MSCs when cultured on HA-PLG scaffolds compared to PLG controls. Upon implantation into an orthotopic calvarial defect, ECFC survival on composite scaffolds was not increased in the presence of MSCs, nor did the addition of ECFCs enhance vascularization beyond increases observed with MSCs alone. Microcomputed tomography (micro-CT) performed on explanted calvarial tissues after 12 weeks revealed no significant differences between treatment groups for bone volume fraction (BVF) or bone mineral density (BMD). Taken together, these results provide evidence that HA-containing composite scaffolds seeded with MSCs can enhance neovascularization, yet MSC-secreted trophic factors do not consistently increase the persistence of co-transplanted ECFCs.

Human umbilical cord matrix stem cells efficiently rescue acute liver failure through paracrine effects rather than hepatic differentiation

There is increasing evidence that mesenchymal stem cells (MSCs) derived from different tissues could act as an alternative source of mature hepatocytes for treatment of acute liver failure (ALF). Human umbilical cord matrix stem cells (hUCMSCs) represent a novel source of MSCs. We examined the therapeutic potential and the different mechanisms of hUCMSCs by their transplantation into nonobese diabetic severe combined-immunodeficient (NOD-SCID) mice with carbon tetrachloride (CCl(4))-induced ALF in comparison to adult human hepatocytes (AHHs). The characteristics of isolated hUCMSCs were determined from MSCs and hepatocyte marker expression, hepatic function, and differentiation. Native hUCMSCs constitutively expressed some hepatic markers, though weaker hepatocyte-specific functions were observed when compared to AHHs. When native hUCMSCs or AHHs were transplanted into livers of NOD-SCID mice with ALF induced by CCl(4), both hUCMSCs and AHHs provided a significant survival benefit and prevented the release of liver injury biomarkers. hUCMSCs were found to engraft within the recipient liver and differentiated into functional hepatocytes, whereas the HepPar1-/albumin (ALB)-positive cells of the hUCMSC group were less than the AHH group in the recipient liver. Higher values of human ALB in the serum of mice-transplanted AHHs were determined in comparison with levels in mice-transplanted hUCMSCs. The analysis of mouse serum cytokine levels showed that hUCMSC transplantation was even more effective than treatment with AHHs and successfully downregulated the systemic inflammatory cytokines such as interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6, IL-10, and IL-1 receptor antagonist (IL-1RA). Furthermore, paracrine effects produced by hUCMSCs were identified by indirect coculture with damaged mouse hepatocytes (MHs) induced by CCl(4). Coculture with hUCMSCs significantly increased the viability, ALB secretion of damaged MHs, and greatly enhanced the regeneration of MHs in vitro when compared with AHHs. These data suggest that direct transplantation of native hUCMSCs can rescue ALF and repopulate livers of mice through paracrine effects to stimulate endogenous liver regeneration rather than hepatic differentiation for compensated liver function, which is the primary effect of AHHs. Thus, hUCMSCs can be a potential alternative source of AHHs for cell therapy of ALF and eliminate the shortage of hepatocytes.

The secretome of stem cells isolated from the adipose tissue and Wharton jelly acts differently on central nervous system derived cell populations

Introduction

It is hypothesized that administration of stromal/stem cells isolated from the adipose tissue (ASCs) and umbilical cord (HUCPVCs) can ameliorate the injured central nervous system (CNS). It is still not clear, however, whether they have similar or opposite effects on primary cultures of neuronal populations. The objective of the present work was to determine if ASCs and HUCPVCs preferentially act, or not, on specific cell populations within the CNS.

Methods

Primary cultures of hippocampal neurons were exposed to ASCs and HUCPVCs conditioned media (CM) (obtained 24, 48, 72 and 96 hours after three days of culture) for one week.

Results

Cell viability experiments (MTS (3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2(4-sulfophenyl)-2H tetrazolium) test) revealed that CM obtained from both cell populations at all time points did not cause any deleterious effects on neuronal cells. In fact, it was determined that whenever the ASCs CM were supplemented with basic fibroblast growth factor (bFGF) and B27, there was a significant increase in the metabolic viability and neuronal cell density of the cultures. On the other hand, in the absence of CM supplementation, it was the HUCPVCs secretome that had the highest impact on the metabolic viability and cell density. In an attempt to unveil which factors could be involved in the observed effects, a screening for the presence of bFGF, nerve growth factor (NGF), stem cell factor (SCF), hepatocyte growth factors (HGF) and vascular endothelial growth factor (VEGF) in the CM was performed. Results revealed the presence of all these factors in ASCs CM, except bFGF; in contrast, in HUCPVCs CM it was only possible to detect robust NGF expression.

Conclusions

Overall, the results confirm important differences on the secretome of ASCs and HUCPVCs, which lead to distinct effects on the metabolic viability and neuronal cell densities in primary cultures of hippocampal neurons; however, the factor(s) that promote the stronger effect of the HUCPVCs CM in neuronal survival is(are) still to be identified.

Characterization and functionality of the CD200-CD200R system during mesenchymal stromal cell interactions with T-lymphocytes

Mesenchymal stromal cells (MSCs) possess a specific immunological profile that makes them potentially useful for immune-based therapies. Adipose tissue (AT) and Wharton's jelly (WJ) are considered to be valuable alternatives to bone marrow (BM) as sources of MSCs. These MSCs exhibit strong immunomodulatory properties that affect lymphocyte responses. The CD200/CD200R axis has been reported to be important in regulating the immune responses. Engagement of CD200R by CD200 initiates an inhibitory pathway that displays immunosuppressive effects. Because the CD200/CD200R axis is involved in immunoregulation, we investigated the expression and role of this ligand/receptor pair in MSCs and T-lymphocytes during co-culture. CD200 is differently expressed and modulated on MSCs depending on the tissue of origin and the culture conditions. Among the different MSC sources, WJ-MSCs express CD200 in the greatest proportion. This high constitutive CD200 expression may represent a distinctive marker for WJ-MSCs. A pro-inflammatory environment and IFN-γ in particular induce an increase in CD200 expression by BM-MSCs. In T-lymphocytes, CD200R and CD200 are differently distributed between the CD4(+) and CD8(+) T-cell subsets. During co-culture, blocking CD200-CD200R interactions does not prevent MSC-mediated inhibition of lymphocyte proliferation. However, depending on their origin, MSCs are able to modulate the expression of both CD200 and CD200R on some T-cells. Further study is required to understand the function of CD200 expression by nonmyeloid cells such MSCs and the significance of CD200 and C200R expression by T-cells. The findings presented here support bidirectional communication between MSCs and T-lymphocytes. Understanding the role of this ligand-receptor pair during co-culture will improve and increase the clinical use of MSCs.

Influence of nanomaterials on stem cell differentiation: designing an appropriate nanobiointerface

During the last decade, due to advances in functionalization chemistry, novel nanobiomaterials with applications in tissue engineering and regenerative medicine have been developed. These novel materials with their unique physical and chemical properties are bioactive hierarchical structures that hold great promise for future development of human tissues. Thus, various nanomaterials are currently being intensively explored in the directed differentiation of stem cells, the design of novel bioactive scaffolds, and new research avenues towards tissue regeneration. This paper illustrates the latest achievements in the applications of nanotechnology in tissue engineering in the field of regenerative medicine.

Therapeutic effect of transplantation of human amniotic membrane- and umbilical cord-derived mesenchymal stem cells on hepatic cirrhosis in rats

AIM: To evaluate the therapeutic effect of transplantation of human amniotic membrane-derived mesenchymal stem cells (hAM-MSCs) and human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) on carbon tetrachloride (CCl₄)-induced hepatic cirrhosis in rats.

METHODS: hAM-MSCs and hUC-MSCs were isolated and analyzed by flow cytometry for detection of expression of CD44, CD29 and CD34. Hepatic cirrhosis was induced in rats with CCl₄. At week 8, five rats were killed to conduct pathological examination to confirm successful induction of hepatic cirrhosis, and 30 rats with hepatic cirrhosis were randomly and equally divided into three groups: hAM-MSCs group, hUC-MSCs group and control group. The hAM-MSCs and hUC-MSCs groups were infused wit 2×10⁶ MSCs in 2 mL of saline via the tail vein, while the control group was given equal volume of saline. Liver function was examined before cell transplantation and 4 wk after cell transplantation. HE staining and Masson dyeing were performed to observe pathological changes in the liver. The expression of alpha-smooth muscle actin (α-SMA) in the liver was determined by immunohistochemistry.

RESULTS: Both isolated hAM-MSCs and hUC-MSCs expressed CD29 and CD44, but did not express CD34. After cell transplantation, liver function parameters were markedly improved (all P < 0.05) and the expression of α-SMA was reduced in the hAM-MSCs and hUC-MSCs groups compared to the control group (130.6 ± 3.0, 127.0 ± 2.6 vs 152.2 ± 5.4, both P < 0.05). There were no statistically significant differences in liver function parameters and α-SMA expression between the hAM-MSCs and hUC-MSCs groups.

CONCLUSION: Transplantation of hAM-MSCs and hUC-MSCs could efficiently improve liver functions and inhibit liver fibrosis in rats.

Minced umbilical cord fragments as a source of cells for orthopaedic tissue engineering: an in vitro study

A promising approach for musculoskeletal repair and regeneration is mesenchymal-stem-cell- (MSC-)based tissue engineering. The aim of the study was to apply a simple protocol based on mincing the umbilical cord (UC), without removing any blood vessels or using any enzymatic digestion, to rapidly obtain an adequate number of multipotent UC-MSCs. We obtained, at passage 1 (P1), a mean value of 4, 2 × 10⁶ cells (SD 0,4) from each UC. At immunophenotypic characterization, cells were positive for CD73, CD90, CD105, CD44, CD29, and HLA-I and negative for CD34 and HLA-class II, with a subpopulation negative for both HLA-I and HLA-II. Newborn origin and multilineage potential toward bone, fat, cartilage, and muscle was demonstrated. Telomere length was similar to that of bone-marrow (BM) MSCs from young donors. The results suggest that simply collecting UC-MSCs at P1 from minced umbilical cord fragments allows to achieve a valuable population of cells suitable for orthopaedic tissue engineering.

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.

Bone marrow mesenchymal cells: how do they contribute to tissue repair and are they really stem cells?

Adult stem cells typically generate the cell types of the tissue in which they reside, and thus the range of their differentiation is considered limited. Bone marrow mesenchymal stem cells (MSCs) are different from other somatic stem cells in that they differentiate not only into the same mesodermal-lineage such as bone, cartilage, and adipocytes but also into other lineages of ectodermal and endodermal cells. Thus, MSCs are a unique type of adult stem cells. In addition, MSCs home to damaged sites, differentiate into cells specific to the tissue and contribute to tissue repair. Therefore, application of MSCs in the treatment of various diseases, including liver dysfunction, myocardial infarction, and central nervous system repair, has been initiated. Because MSCs are generally harvested as adherent cells from bone marrow aspirates, however, they comprise heterogeneous cell populations and their wide-ranging differentiation ability and repair functions are not yet clear. Recent evidence suggests that a very small subpopulation of cells that assume a repair function with the ability to differentiate into trilineage cells resides among human MSCs and effective utilization of such cells is expected to improve the repair effect of MSCs. This review summarizes recent advances in the clarification of MSC properties and discusses future perspectives.

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.

Minimally manipulated whole human umbilical cord is a rich source of clinical-grade human mesenchymal stromal cells expanded in human platelet lysate

BACKGROUND AIMS

Mesenchymal stromal cells (MSC) have recently been identified as a therapeutic option in several clinical conditions. Whereas bone marrow (BM) is considered the main source of MSC (BM-MSC), the invasive technique required for collection and the decline in allogeneic donations call for alternative sources. Human umbilical cord (UC) represents an easily available source of MSC (UC-MSC).

METHODS

Sections of full-term UC were transferred to cell culture flasks and cultured in 5% human platelet lysate (PL)-enriched medium. Neither enzymatic digestion nor blood vessel removal was performed. After 2 weeks, the adherent cells were harvested (P1), replated at low density and expanded for two consecutive rounds (P2 and P3).

RESULTS

We isolated and expanded MSC from 9/9 UC. UC-MSC expanded with a mean fold increase (FI) of 42 735 ± 16 195 from P1 to P3 in a mean of 29 ± 2 days. By processing the entire cord unit, we theoretically could have reached a median of 9.5 × 10(10) cells (ranging from 1.0 × 10(10) to 29.0 × 10(10)). UC-MSC expressed standard surface markers; they contained more colony-forming unit (CFU)-fibroblast (F) and seemed less committed towards osteogenic, chondrogenic and adipogenic lineages than BM-MSC. They showed immunosuppressive properties both in vitro and in an in vivo chronic Graft versus Host disease (cGvHD) mouse model. Both array-Comparative Genomic Hybridization (CGH) analysis and karyotyping revealed no chromosome alterations at the end of the expansion. Animal studies revealed no tumorigenicity in vivo.

CONCLUSIONS

UC constitute a convenient and very rich source of MSC for the production of third-party 'clinical doses' of cells under good manufacturing practice (GMP) conditions.

NT-3-secreting human umbilical cord mesenchymal stromal cell transplantation for the treatment of acute spinal cord injury in rats

An animal model for clip spinal cord injury (SCI) was used to determine whether Neurotrophin-3 (NT-3) genetically modified human umbilical mesenchymal stem cells (NT-3-HUMSCs) could promote the morphologic and functional recovery of injured spinal cords. Using the Basso, Beattie, and Bresnahan scores and a grid test, the rats in the HUMSC-treated and NT-3-HUMSCs groups had significantly improved locomotor functional recovery more than the control group. In comparison, the NT-3-HUMSCs group achieved better functional recovery than the HUMSCs group at the end of 12 weeks after SCI. The functional recovery was accompanied by increased intensity of 5-HT fibers, increased volume of spared myelination, and decreased area of the cystic cavity in the NT-3-HUMSCs group compared with the HUMSCs group. Moreover, transplanted NT-3-HUMSCs survived and produced larger amounts of NT-3 than the HUMSCs in the host spinal cord. These results show that NT-3 enhanced the therapeutic effects of HUMSCs after clip injury of the spinal cord.