Assessment of the Neuroprotective and Stemness Properties of Human Wharton's Jelly-Derived Mesenchymal Stem Cells under Variable (5% vs. 21%) Aerobic Conditions.

To optimise the culture conditions for human Wharton's jelly-derived mesenchymal stem cells (hWJ-MSCs) intended for clinical use, we investigated ten different properties of these cells cultured under 21% (atmospheric) and 5% (physiological normoxia) oxygen concentrations. The obtained results indicate that 5% O2 has beneficial effects on the proliferation rate, clonogenicity, and slowdown of senescence of hWJ-MSCs; however, the oxygen level did not have an influence on the cell morphology, immunophenotype, or neuroprotective effect of the hWJ-MSCs. Nonetheless, the potential to differentiate into adipocytes, osteocytes, and chondrocytes was comparable under both oxygen conditions. However, spontaneous differentiation of hWJ-MSCs into neuronal lineages was observed and enhanced under atmospheric oxygen conditions. The cells relied more on mitochondrial respiration than glycolysis, regardless of the oxygen conditions. Based on these results, we can conclude that hWJ-MSCs could be effectively cultured and prepared under both oxygen conditions for cell-based therapy. However, the 5% oxygen level seemed to create a more balanced and appropriate environment for hWJ-MSCs.

Biomimetic microenvironmental preconditioning enhance neuroprotective properties of human mesenchymal stem cells derived from Wharton's Jelly (WJ-MSCs).

Tuning stem cells microenvironment in vitro may influence their regenerative properties. In this study Wharton's Jelly-derived mesenchymal stem cells (WJ-MSCs) were encapsulated in 3D hydrogels derived from human fibrin (FB) or platelet lysate (PL) and the oxygen level was adjusted to physiological normoxia (5% O2). The influence of the type of the scaffold and physiological normoxia conditions was tested on the WJ-MSCs' survivability, proliferation, migratory potential, the level of expression of selected trophic factors, cytokines, and neural markers. Encapsulated WJ-MSCs revealed high survivability, stable proliferation rate, and ability to migrate out of the hydrogel and the up-regulated expression of all tested factors, as well as the increased expression of neural differentiation markers. Physiological normoxia stimulated proliferation of encapsulated WJ-MSCs and significantly enhanced their neuronal, but not glial, differentiation. Ex vivo studies with indirect co-culture of organotypic hippocampal slices and cell-hydrogel bio-constructs revealed strong neuroprotective effect of WJ-MSCs against neuronal death in the CA1 region of the rat hippocampus. This effect was potentiated further by FB scaffolds under 5% O2 conditions. Our results indicating significant effect of oxygen and 3D cytoarchitecture suggest the urgent need for further optimization of the microenvironmental conditions to improve therapeutical competence of the WJ-MSCs population.

Bone Defect Repair Using a Bone Substitute Supported by Mesenchymal Stem Cells Derived from the Umbilical Cord.

OBJECTIVE: Bone defects or atrophy may arise as a consequence of injury, inflammation of various etiologies, and neoplastic or traumatic processes or as a result of surgical procedures. Sometimes the regeneration process of bone loss is impaired, significantly slowed down, or does not occur, e.g., in congenital defects. For the bone defect reconstruction, a piece of the removed bone from ala of ilium or bone transplantation from a decedent is used. Replacement of the autologous or allogenic source of the bone-by-bone substitute could reduce the number of surgeries and time in the pharmacological coma during the reconstruction of the bone defect. Application of mesenchymal stem cells in the reconstruction surgery may have positive influence on tissue regeneration by secretion of angiogenic factors, recruitment of other MSCs, or differentiation into osteoblasts. Materials and Methods. Mesenchymal stem cells derived from the umbilical cord (Wharton's jelly (WJ-MSC)) were cultured in GMP-grade DMEM low glucose supplemented with heparin, 10% platelet lysate, glucose, and antibiotics. In vitro WJ-MSCs were seeded on the bone substitute Bio-Oss Collagen® and cultured in the StemPro® Osteogenesis Differentiation Kit. During the culture on the 1st, 7th, 14th, and 21st day (day in vitro (DIV)), we analyzed viability (confocal microscopy) and adhesion capability (electron microscopy) of WJ-MSC on Bio-Oss scaffolds, gene expression (qPCR), and secretion of proteins (Luminex). In vivo Bio-Oss® scaffolds with WJ-MSC were transplanted to trepanation holes in the cranium to obtain their overgrowth. The computed tomography was performed 7, 14, and 21 days after surgery to assess the regeneration. RESULTS: The Bio-Oss® scaffold provides a favourable environment for WJ-MSC survival. WJ-MSCs in osteodifferentiation medium are able to attach and proliferate on Bio-Oss® scaffolds. Results obtained from qPCR and Luminex® indicate that WJ-MSCs possess the ability to differentiate into osteoblast-like cells and may induce osteoclastogenesis, angiogenesis, and mobilization of host MSCs. In animal studies, WJ-MSCs seeded on Bio-Oss® increased the scaffold integration with host bone and changed their morphology to osteoblast-like cells. CONCLUSIONS: The presented construct consisted of Bio-Oss®, the scaffold with high flexibility and plasticity, approved for clinical use with seeded immunologically privileged WJ-MSC which may be considered reconstructive therapy in bone defects.

Phenotypic, Functional, and Safety Control at Preimplantation Phase of MSC-Based Therapy.

Mesenchymal stem cells (MSC) exhibit enormous heterogeneity which can modify their regenerative properties and therefore influence therapeutic effectiveness as well as safety of these cells transplantation. In addition the high phenotypic plasticity of MSC population makes it enormously sensitive to any changes in environmental properties including fluctuation in oxygen concentration. We have shown here that lowering oxygen level far below air atmosphere has a beneficial impact on various parameters characteristic for umbilical cord Wharton Jelly- (WJ-) MSC and adipose tissue- (AD-) derived MSC cultures. This includes their cellular composition, rate of proliferation, and maintenance of stemness properties together with commitment to cell differentiation toward mesodermal and neural lineages. In addition, the culture genomic stability increased significantly during long-term cell passaging and eventually protected cells against spontaneous transformation. Also by comparing of two routinely used methods of MSCs isolation (mechanical versus enzymatic) we have found substantial divergence arising between cell culture properties increasing along the time of cultivation in vitro. Thus, in this paper we highlight the urgent necessity to develop the more sensitive and selective methods for prediction and control cells fate and functioning during the time of growth in vitro.

Enhanced neuro-therapeutic potential of Wharton's Jelly-derived mesenchymal stem cells in comparison with bone marrow mesenchymal stem cells culture.

Substantial inconsistencies in mesenchymal stem (stromal) cell (MSC) therapy reported in early translational and clinical studies may indicate need for selection of the proper cell population for any particular therapeutic purpose. In the present study we have examined stromal stem cells derived either from umbilical cord Wharton's Jelly (WJ-MSC) or bone marrow (BM-MSC) of adult, healthy donors. The cells characterized in accordance with the International Society for Cellular Therapy (ISCT) indications as well as other phenotypic and functional parameters have been compared under strictly controlled culture conditions. WJ-MSC, in comparison with BM-MSC, exhibited a higher proliferation rate, a greater expansion capability being additionally stimulated under low-oxygen atmosphere, enhanced neurotrophic factors gene expression and spontaneous tendency toward a neural lineage differentiation commitment confirmed by protein and gene marker induction. Our data suggest that WJ-MSC may represent an example of immature-type "pre-MSC," where a substantial cellular component is embryonic-like, pluripotent derivatives with the default neural-like differentiation. These cells may contribute in different extents to nearly all classical MSC populations adversely correlated with the age of cell donors. Our data suggest that neuro-epithelial markers, like nestin, stage specific embryonic antigens-4 or α-smooth muscle actin expressions, may serve as useful indicators of MSC culture neuro-regeneration-associated potency.

Induction of Endothelial Phenotype From Wharton's Jelly-Derived MSCs and Comparison of Their Vasoprotective and Neuroprotective Potential With Primary WJ-MSCs in CA1 Hippocampal Region Ex Vivo.

Ischemic stroke results in violent impairment of tissue homeostasis leading to severe perturbation within the neurovascular unit (NVU) during the recovery period. The aim of this study was to assess the potential of mesenchymal stem cells (MSCs) originating from Wharton's jelly (WJ) to differentiate into functionally competent cells of endothelial lineage (WJ-EPCs). The protective effect(s) of either primary WJ-MSCs or induced WJ-EPCs was investigated and compared after oxygen-glucose deprivation (OGD) of hippocampal organotypic slices (OHC) in the indirect coculture model. WJ-MSCs, primed in EGM-2 (Lonza commercial medium) under 5% O2, acquired cobblestone endothelial-like morphology, formed capillary-like structures and actively took up DiI-Ac-LDL. Both cell types (WJ-MSCs and WJ-EPCs) were positive for CD73, CD90, CD105, VEGFR-2, and VEGF, but only endothelial-like culture expressed vWF and PECAM-1 markers at significant levels. In the presence of either WJ-MSCs or WJ-EPCs in the compartment below OGD-injured slices, cell death and vascular atrophy in the hypoxia-sensitive CA1 region were substantially decreased. This suggests that a paracrine mechanism may mediate WJ-MSC- and WJ-EPC-dependent protection. Thus, finally, we estimated secretion of the neuro/angio/immunomodulatory molecules IL-6, TGF-ß1, and VEGF by these cell cultures. We have found that release of TGF-ß1 and IL-6 was TLR ligand [LPS and Poly(I:C)] concentration dependent and stronger in WJ-EPC than WJ-MSC cultures. Simultaneously, the uneven pattern of TLR receptors and modulatory cytokine gene expression was confirmed also on qRT-PCR level, but no significant differences were noticed between WJ-EPC and primary WJ-MSC cultures.