Distinct differentiation potential of "MSC" derived from cord blood and umbilical cord: are cord-derived cells true mesenchymal stromal cells?

Methylglyoxal-induced neurotoxic effects in primary neuronal-like cells transdifferentiated from human mesenchymal stem cells: Impact of low concentrations

In the last decades, advanced glycation end-products (AGEs) have aroused the interest of the scientific community due to the increasing evidence of their involvement in many pathophysiological processes including various neurological disorders and cognitive decline age related. Methylglyoxal (MG) is one of the reactive dicarbonyl precursors of AGEs, mainly generated as a by-product of glycolysis, whose accumulation induces neurotoxicity. In our study, MG cytotoxicity was evaluated employing a human stem cell-derived model, namely, neuron-like cells (hNLCs) transdifferentiated from mesenchymal stem/stromal cells, which served as a source of human based species-specific "healthy" cells. MG increased ROS production and induced the first characteristic apoptotic hallmarks already at low concentrations (≥10 μM), decreased the cell growth (≥5-10 μM) and viability (≥25 μM), altered Glo-1 and Glo-2 enzymes (≥25 μM), and markedly affected the neuronal markers MAP-2 and NSE causing their loss at low MG concentrations (≥10 μM). Morphological alterations started at 100 μM, followed by even more marked effects and cell death after few hours (5 h) from 200 μM MG addition. Substantially, most effects occurred as low as 10 μM, concentration much lower than that reported from previous observations using different in vitro cell-based models (e.g., human neuroblastoma cell lines, primary animal cells, and human iPSCs). Remarkably, this low effective concentration approaches the level range measured in biological samples of pathological subjects. The use of a suitable cellular model, that is, human primary neurons, can provide an additional valuable tool, mimicking better the physiological and biochemical properties of brain cells, in order to evaluate the mechanistic basis of molecular and cellular alterations in CNS.

Mechanisms and Optimization Strategies of Paracrine Exosomes from Mesenchymal Stem Cells in Ischemic Heart Disease

The morbidity and mortality of myocardial infarction (MI) are increasing worldwide. Mesenchymal stem cells (MSCs) are multipotent stem cells with self-renewal and differentiation capabilities that are essential in tissue healing and regenerative medicine. However, the low implantation and survival rates of transplanted cells hinder the widespread clinical use of stem cells. Exosomes are naturally occurring nanovesicles that are secreted by cells and promote the repair of cardiac function by transporting noncoding RNA and protein. In recent years, MSC-derived exosomes have been promising cell-free treatment tools for improving cardiac function and reversing cardiac remodeling. This review describes the biological properties and therapeutic potential of exosomes and summarizes some engineering approaches for exosomes optimization to enhance the targeting and therapeutic efficacy of exosomes in MI.

A robust and standardized method to isolate and expand mesenchymal stromal cells from human umbilical cord

BACKGROUND AIMS

Human umbilical cord-derived mesenchymal stromal cells (hUC-MSCs) are increasingly used in research and therapy. To obtain hUC-MSCs, a diversity of isolation and expansion methods are applied. Here, we report on a robust and standardized method for hUC-MSC isolation and expansion.

METHODS

Using 90 hUC donors, we compared and optimized critical variables during each phase of the multi-step procedure involving UC collection, processing, MSC isolation, expansion and characterization. Furthermore, we assessed the effect of donor-to-donor variability regarding UC morphology and donor attributes on hUC-MSC characteristics.

RESULTS

We demonstrated robustness of our method across 90 UC donors at each step of the procedure. With our method, UCs can be collected up to 6 h after birth, and UC-processing can be initiated up to 48 h after collection without impacting on hUC-MSC characteristics. The removal of blood vessels before explant cultures improved hUC-MSC purity. Expansion in Minimum essential medium α supplemented with human platelet lysate increased reproducibility of the expansion rate and MSC characteristics as compared with Dulbecco's Modified Eagle's Medium supplemented with fetal bovine serum. The isolated hUC-MSCs showed a purity of ∼98.9%, a viability of >97% and a high proliferative capacity. Trilineage differentiation capacity of hUC-MSCs was reduced as compared with bone marrow-derived MSCs. Functional assays indicated that the hUC-MSCs were able to inhibit T-cell proliferation demonstrating their immune-modulatory capacity.

CONCLUSIONS

We present a robust and standardized method to isolate and expand hUC-MSCs, minimizing technical variability and thereby lay a foundation to advance reliability and comparability of results obtained from different donors and different studies.

TMT-Based Quantitative Proteomics Analysis Reveals Differentially Expressed Proteins between Different Sources of hMSCs

Mesenchymal stem cells (MSCs) are an attractive therapeutic tool for tissue engineering and regenerative medicine owing to their regenerative and trophic properties. The best-known and most widely used are bone marrow MSCs, which are currently being harvested and developed from a wide range of adult and perinatal tissues. MSCs from different sources are believed to have different secretion potentials and production, which may influence their therapeutic effects. To confirm this, we performed a quantitative proteomic analysis based on the TMT technique of MSCs from three different sources: Wharton's jelly (WJ), dental pulp (DP), and bone marrow (BM). Our analysis focused on MSC biological properties of interest for tissue engineering. We identified a total of 611 differentially expressed human proteins. WJ-MSCs showed the greatest variation compared with the other sources. WJ produced more extracellular matrix (ECM) proteins and ECM-affiliated proteins and proteins related to the inflammatory and immune response processes. BM-MSCs expressed more proteins involved in osteogenic, adipogenic, neuronal, or muscular differentiation and proteins involved in paracrine communication. Compared to the other sources, DP-MSCs overexpressed proteins involved in the exocytosis process. The results obtained confirm the existence of differences between WJ, DP, and BM-MSCs and the need to select the MSC origin according to the therapeutic objective sought.

Mesenchymal Stromal Cells: Heterogeneity and Therapeutical Applications

Mesenchymal stromal cells nowadays emerge as a major player in the field of regenerative medicine and translational research. They constitute, with their derived products, the most frequently used cell type in different therapies. However, their heterogeneity, including different subpopulations, the anatomic source of isolation, and high donor-to-donor variability, constitutes a major controversial issue that affects their use in clinical applications. Furthermore, the intrinsic and extrinsic molecular mechanisms underlying their self-renewal and fate specification are still not completely elucidated. This review dissects the different heterogeneity aspects of the tissue source associated with a distinct developmental origin that need to be considered when generating homogenous products before their usage for clinical applications.

Mesenchymal Stem Cells: Generalities and Clinical Significance in Feline and Canine Medicine

Mesenchymal stem cells (MSCs) are multipotent cells: they can proliferate like undifferentiated cells and have the ability to differentiate into different types of cells. A considerable amount of research focuses on the potential therapeutic benefits of MSCs, such as cell therapy or tissue regeneration, and MSCs are considered powerful tools in veterinary regenerative medicine. They are the leading type of adult stem cells in clinical trials owing to their immunosuppressive, immunomodulatory, and anti-inflammatory properties, as well as their low teratogenic risk compared with pluripotent stem cells. The present review details the current understanding of the fundamental biology of MSCs. We focus on MSCs' properties and their characteristics with the goal of providing an overview of therapeutic innovations based on MSCs in canines and felines.

Role of Epicardial Adipose Tissue Secretome on Cardiovascular Diseases

Obesity and insulin resistance are associated with the inflamed and defective adipose tissue (AT) phenotype, and are established risk factors for cardiovascular diseases (CVDs). Extracellular vesicles (EVs) are a heterogeneous group of cell-derived lipid membrane vesicles involved in the onset and development of many pathologies, including insulin resistance, diabetes, and CVDs. The inflammation associated with overweight and obesity triggers the transition of the AT secretome from healthy to pathological, with a consequent increased expression of pro-inflammatory mediators. Epicardial adipose tissue (EAT) is a specialized fat depot that surrounds the heart, in direct contact with the myocardium. Recently, the role of EAT in regulating the physiopathology of many heart diseases has been increasingly explored. In particular, the EAT phenotype and derived EVs have been associated with the onset and exacerbation of CVDs. In this review, we will focus on the role of the AT secretome in the case of CVDs, and will discuss the beneficial effects of EVs released by AT as promising therapeutic candidates.

Mesenchymal stromal cells as a tool to unravel the developmental origins of disease

The intrauterine environment can induce alterations of the epigenome that have a lasting impact on disease risk. Current human studies in the field focus on a single epigenetic mark, DNA methylation, measured in blood. For in-depth mechanistic insight into the developmental origins of disease, it will be crucial to consider innovative tissue types. Mesenchymal stromal cells (MSCs) may serve as a novel tool to investigate the full epigenome beyond DNA methylation, to explore other omics levels, and to perform functional assays. Moreover, MSCs can be differentiated into multiple cell types and thereby mimic otherwise inaccessible cell types. A first wave of studies supports the potential of MSCs and illustrates how the innovative use of this cell type may be incorporated in birth cohorts.

Mesenchymal stem cells derived from different perinatal tissues donated by same donors manifest variant performance on the acute liver failure model in mouse

Background

Mesenchymal stem cells (MSCs) derived from different tissues have variant biological characteristics, which may induce different performances in the treatment of diseases. At present, it is difficult to know which type of MSC is most suitable for acute liver failure (ALF), and there is no parallel study to compare MSCs from different tissues of the same donor.

Methods

In this study, we derived MSCs from three different perinatal tissues of the same donor: cord lining (CL), cord–placenta junction (CPJ) and fetal placenta (FP), respectively, for compared gene expression profiles by transcriptome sequencing, and ability of proliferation and immune regulation in vitro. In addition, the therapeutic effects (e.g., survival rate, histological evaluation, biochemical analysis) of CL-MSCs, FP-MSCs and CPJ-MSCs on ALF mouse model were compared.

Results

The transcriptome analysis showed that FP-MSCs have significantly high expression of chemokines compared to CPJ-MSCs and CL-MSCs, similar to the q-PCR result. Of note, we found that CPJ-MSCs and FP-MSCs could improve the survival rate of mice with ALF induced by carbon tetrachloride, but CL-MSCs had no difference with Sham group. Moreover, we also found that biomarkers of ALF (e.g., MDA, SOD and GSH-px) significantly improved post-CPJ-MSCs and FP-MSCs treatment, but not CL-MSCs and Sham group. However, CL-MSCs treatment leads to inflammatory reaction in the early stage (day 3) of ALF treatment but not found with other groups.

Conclusions

It is important to select the MSCs derived from different tissues with variant performance for therapeutic purpose, and the CPJ-MSCs and FP-MSCs cells can significantly improve the syndrome of ALF which is highly recommended for a potential therapeutic options for ALF.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02909-w.

Human Umbilical Cord Mesenchymal Stem Cell-Based in vitro Model for Neurotoxicity Testing

Neurotoxicity (NT) testing for regulatory purposes is based on in vivo animal testing. There is general consensus, however, about the need for the development of alternative methodologies to allow researchers to more rapidly and cost effectively screen large numbers of chemicals for their potential to cause NT, or to investigate their mode of action. In vitro assays are considered an important source of information for making regulatory decisions, and human cell-based systems are recommended as one of the most relevant models in toxicity testing, to reduce uncertainty in the extrapolation of results from animal-based models. Human neuronal models range from various neuroblastoma cell lines to stem cell-derived systems, including those derived from mesenchymal stem/stromal cells (hMSC). hMSCs exhibit numerous advantages, including the fact that they can be obtained in high yield from healthy human adult tissues, can be cultured with a minimal laboratory setup and without genetic manipulations, are able of continuous and repeated self-renewal, are nontumorigenic, and can form large populations of stably differentiated cells representative of different tissues, including neuronal cells. hMSCs derived from human umbilical cord (hUC) in particular possess several prominent advantages, including a painless, non-invasive, and ethically acceptable collection procedure, simple and convenient preparation, and high proliferation capacity. In addition, hMSCs can be efficiently differentiated into neuron-like cells (hNLCs), which can then be used for the assessment of neuronal toxicity of potential neurotoxic compounds in humans. Here, we describe a step-by-step procedure to use hMSCs from the umbilical cord for in vitro neurotoxicity testing. First, we describe how to isolate, amplify, and store hMSCs derived from the umbilical cord. We then outline the steps to transdifferentiate these cells into hNLCs, and then use the hNLCs for neurotoxicity testing by employing multiple common cytotoxicity assays after treatment with test compounds. The approach follows the most updated guidance on using human cell-based systems. These protocols will allow investigators to implement an alternative system for obtaining primary NLCs of human origin, and support advancement in neurotoxicity research. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Isolation and maintenance of human mesenchymal stem/stromal cells (hMSCs) obtained from the umbilical cord lining membrane Basic Protocol 2: Transdifferentiation of hMSCs into neuron-like cells (hNLCs) and basic neurotoxicity assessment.

Stem Cell Transplantation Therapy and Neurological Disorders: Current Status and Future Perspectives

Neurodegenerative diseases are a global health issue with inadequate therapeutic options and an inability to restore the damaged nervous system. With advances in technology, health scientists continue to identify new approaches to the treatment of neurodegenerative diseases. Lost or injured neurons and glial cells can lead to the development of several neurological diseases, including Parkinson's disease, stroke, and multiple sclerosis. In recent years, neurons and glial cells have successfully been generated from stem cells in the laboratory utilizing cell culture technologies, fueling efforts to develop stem cell-based transplantation therapies for human patients. When a stem cell divides, each new cell has the potential to either remain a stem cell or differentiate into a germ cell with specialized characteristics, such as muscle cells, red blood cells, or brain cells. Although several obstacles remain before stem cells can be used for clinical applications, including some potential disadvantages that must be overcome, this cellular development represents a potential pathway through which patients may eventually achieve the ability to live more normal lives. In this review, we summarize the stem cell-based therapies that have been explored for various neurological disorders, discuss the potential advantages and drawbacks of these therapies, and examine future directions for this field.

Novel cell sources for bone regeneration

A plethora of both acute and chronic conditions, including traumatic, degenerative, malignant, or congenital disorders, commonly induce bone disorders often associated with severe persisting pain and limited mobility. Over 1 million surgical procedures involving bone excision, bone grafting, and fracture repair are performed each year in the U.S. alone, resulting in immense levels of public health challenges and corresponding financial burdens. Unfortunately, the innate self-healing capacity of bone is often inadequate for larger defects over a critical size. Moreover, as direct transplantation of committed osteoblasts is hindered by deficient cell availability, limited cell spreading, and poor survivability, an urgent need for novel cell sources for bone regeneration is concurrent. Thanks to the development in stem cell biology and cell reprogramming technology, many multipotent and pluripotent cells that manifest promising osteogenic potential are considered the regenerative remedy for bone defects. Considering these cells' investigation is still in its relative infancy, each of them offers their own particular challenges that must be conquered before the large-scale clinical application.

Umbilical Mesenchymal Stem Cell-Derived Exosome-Encapsulated Hydrogels Accelerate Bone Repair by Enhancing Angiogenesis

Repair of large bone defects represents a major challenge for orthopedic surgeons. The newly formed microvessels inside grafts play a crucial role in successful bone tissue engineering. Previously, an active role for mesenchymal stem cell (MSC)-derived exosomes in blood vessel development and progression was suggested in the repair of multiple tissues. However, the reports on the application of MSC-derived exosomes in the repair of large bone defects are sparse. In this study, we encapsulated umbilical MSC-derived exosomes (^uMSCEXOs) in hyaluronic acid hydrogel (HA-Gel) and combined them with customized nanohydroxyapatite/poly-ε-caprolactone (nHP) scaffolds to repair cranial defects in rats. Imaging and histological evaluation indicated that the ^uMSCEXOs/Gel/nHP composites markedly enhanced bone regeneration in vivo, and the ^uMSCEXOs might play a key role in this process. Moreover, the in vitro results demonstrated that ^uMSCEXOs promoted the proliferation, migration, and angiogenic differentiation of endothelial progenitor cells (EPCs) but did not significantly affect the osteogenic differentiation of BMSCs. Importantly, mechanistic studies revealed that exosomal miR-21 was the potential intercellular messenger that promoted angiogenesis by upregulating the NOTCH1/DLL4 pathway. In conclusion, our findings exhibit a promising exosome-based strategy in repairing large bone defects through enhanced angiogenesis, which potentially regulated by the miR-21/NOTCH1/DLL4 signaling axis.

Cell culture media notably influence properties of human mesenchymal stroma/stem-like cells from different tissues

BACKGROUND AIMS

Mesenchymal stroma/stem-like cells (MSCs) are a popular cell source and hold huge therapeutic promise for a broad range of possible clinical applications. However, to harness their full potential, current limitations in harvesting, expansion and characterization have to be overcome. These limitations are related to the heterogeneity of MSCs in general as well as to inconsistent experimental protocols. Here we aim to compare in vitro methods to facilitate comparison of MSCs generated from various tissues.

METHODS

MSCs from 3 different tissues (bone marrow, dental pulp, adipose tissue), exemplified by cells from 3 randomly chosen donors per tissue, were systematically compared with respect to their in vitro properties after propagation in specific in-house standard media, as established in the individual laboratories, or in the same commercially available medium.

RESULTS

Large differences were documented with respect to the expression of cell surface antigens, population doubling times, basal expression levels of 5 selected genes and osteogenic differentiation. The commercial medium reduced differences in these parameters with respect to individual human donors within tissue and between tissues. The extent, size and tetraspanin composition of extracellular vesicles were also affected.

CONCLUSIONS

The results clearly demonstrate the extreme heterogeneity of MSCs, which confirms the problem of reproducibility of results, even when harmonizing experimental conditions, and questions the significance of common parameters for MSCs from different tissues in vitro.

Heparin Anticoagulant for Human Bone Marrow Does Not Influence In Vitro Performance of Human Mesenchymal Stromal Cells

Mesenchymal stromal cells (MSCs) are a promising cell source for tissue engineering and regenerative medicine. In our lab, we found that MSC preparations from bone marrow of many different donors had a limited capacity of in vitro differentiation into osteogenic and chondrogenic lineages-a capacity claimed to be inherent to MSCs. The current study was designed to test the hypothesis that the amount of heparin used as anticoagulant during bone marrow harvest had an inhibitory influence on the in vitro differentiation capacity of isolated MSCs. Bone marrow was obtained from the femoral cavity of twelve donors during total hip arthroplasty in the absence or presence of heparin. No coagulation was observed in the absence of heparin. The number of mononuclear cells was independent of heparin addition. Isolated MSCs were characterized by morphology, population doubling times, expression of cell surface antigens and in vitro differentiation. Results of these analyses were independent of the amount of heparin. Transcriptome analyses of cells from three randomly chosen donors and quantitative realtime PCR (qRT-PCR) analysis from cells of all donors demonstrated no clear effect of heparin on the transcriptome of the cells. This excludes heparin as a potential source of disparate results.

Umbilical Cord MSCs and Their Secretome in the Therapy of Arthritic Diseases: A Research and Industrial Perspective

The prevalence of arthritic diseases is increasing in developed countries, but effective treatments are currently lacking. The injection of mesenchymal stem cells (MSCs) represents a promising approach to counteract the degenerative and inflammatory environment characterizing those pathologies, such as osteoarthritis (OA). However, the majority of clinical approaches based on MSCs are used within an autologous paradigm, with important limitations. For this reason, allogeneic MSCs isolated from cord blood (cbMSCs) and Wharton’s jelly (wjMSCs) gained increasing interest, demonstrating promising results in this field. Moreover, recent evidences shows that MSCs beneficial effects can be related to their secretome rather than to the presence of cells themselves. Among the trophic factors secreted by MSCs, extracellular vesicles (EVs) are emerging as a promising candidate for the treatment of arthritic joints. In the present review, the application of umbilical cord MSCs and their secretome as innovative therapeutic approaches in the treatment of arthritic joints will be examined. With the prospective of routine clinical applications, umbilical cord MSCs and EVs will be discussed also within an industrial and regulatory perspective.

Limited Potential or Unfavorable Manipulations? Strategies Toward Efficient Mesenchymal Stem/Stromal Cell Applications

Despite almost 50 years of research and over 20 years of preclinical and clinical studies, the question of curative potential of mesenchymal stem/stromal cells (MSCs) is still widely discussed in the scientific community. Non-reproducible treatment outcomes or even absence of treatment effects in comparison to control groups challenges the potential of these cells for routine application both in tissue engineering and in regenerative medicine. One of the reasons of such outcomes is non-standardized and often disadvantageous ex vivo manipulation of MSCs prior therapy. In most cases, clinically relevant cell numbers for MSC-based therapies can be only obtained by in vitro expansion of isolated cells. In this mini review, we will discuss point by point possible pitfalls in the production of human MSCs for cell therapies, without consideration of material-based applications. Starting with cell source, choice of donor and recipient, as well as isolation methods, we will then discuss existing expansion protocols (two-/three-dimensional cultivation, basal medium, medium supplements, static/dynamic conditions, and hypoxic/normoxic conditions) and influence of these strategies on the cell functionality after implantation. The role of potency assays will also be addressed. The final aim of this mini review is to illustrate the heterogeneity of current strategies for gaining MSCs for clinical applications with their strengths and weaknesses. Only a careful consideration and standardization of all pretreatment processes/methods for the different applications of MSCs will ensure robust and reproducible performance of these cell populations in the different experimental and clinical settings.

Neuron-Like Cells Generated from Human Umbilical Cord Lining-Derived Mesenchymal Stem Cells as a New In Vitro Model for Neuronal Toxicity Screening: Using Magnetite Nanoparticles as an Example

The wide employment of iron nanoparticles in environmental and occupational settings underlines their potential to enter the brain. Human cell-based systems are recommended as relevant models to reduce uncertainty and to improve prediction of human toxicity. This study aimed at demonstrating the in vitro differentiation of the human umbilical cord lining-derived-mesenchymal stem cells (hCL-MSCs) into neuron-like cells (hNLCs) and the benefit of using them as an ideal primary cell source of human origin for the neuronal toxicity of Fe3O4NPs (magnetite-nanoparticles). Neuron-like phenotype was confirmed by: live morphology; Nissl body staining; protein expression of different neuronal-specific markers (immunofluorescent staining), at different maturation stages (i.e., day-3-early and day-8-full differentiated), namely β-tubulin III, MAP-2, enolase (NSE), glial protein, and almost no nestin and SOX-2 expression. Synaptic makers (SYN, GAP43, and PSD95) were also expressed. Fe3O4NPs determined a concentration- and time-dependent reduction of hNLCs viability (by ATP and the Trypan Blue test). Cell density decreased (20-50%) and apoptotic effects were detected at ≥10 μg/mL in both types of differentiated hNLCs. Three-day-differentiated hNLCs were more susceptible (toxicity appeared early and lasted for up to 48 h) than 8-day-differentiated cells (delayed effects). The study demonstrated that (i) hCL-MSCs easily differentiated into neuronal-like cells; (ii) the hNCLs susceptibility to Fe3O4NPs; and (iii) human primary cultures of neurons are new in vitro model for NP evaluation.

Identification of differentially expressed genes by single-cell transcriptional profiling of umbilical cord and synovial fluid mesenchymal stem cells

The purpose of this study was to measure the heterogeneity in human umbilical cord–derived mesenchymal stem cells (hUC‐MSCs) and human synovial fluid–derived mesenchymal stem cells (hSF‐MSCs) by single‐cell RNA‐sequencing (scRNA‐seq). Using Chromium™ technology, scRNA‐seq was performed on hUC‐MSCs and hSF‐MSCs from samples that passed our quality control checks. In order to identify subgroups and activated pathways, several bioinformatics tools were used to analyse the transcriptomic profiles, including clustering, principle components analysis (PCA), t‐Distributed Stochastic Neighbor Embedding (t‐SNE), gene set enrichment analysis, as well as Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. scRNA‐seq was performed on the two sample sets. In total, there were 104 761 163 reads for the hUC‐MSCs and 6 577 715 for the hSF‐MSCs, with >60% mapping rate. Based on PCA and t‐SNE analyses, we identified 11 subsets within hUC‐MSCs and seven subsets within hSF‐MSCs. Gene set enrichment analysis determined that there were 533, 57, 32, 44, 10, 319, 731, 1037, 90, 25 and 230 differentially expressed genes (DEGs) in the 11 subsets of hUC‐MSCs and 204, 577, 30, 577, 16, 57 and 35 DEGs in the seven subsets of hSF‐MSCs. scRNA‐seq was not only able to identify subpopulations of hUC‐MSCs and hSF‐MSCs within the sample sets, but also provided a digital transcript count of hUC‐MSCs and hSF‐MSCs within a single patient. scRNA‐seq analysis may elucidate some of the biological characteristics of MSCs and allow for a better understanding of the multi‐directional differentiation, immunomodulatory properties and tissue repair capabilities of MSCs.

Exosomes derived from adipose tissue, bone marrow, and umbilical cord blood for cardioprotection after myocardial infarction

Human mesenchymal stem cells (MSCs) have the potential for improving cardiac function following myocardial infarction (MI). This study was performed to explore the cardioprotection of bone marrow mesenchymal stem cells (BMMSCs), adipose tissue-derived mesenchymal stem cells (ADMSCs), and umbilical cord blood-derived mesenchymal stem cells (UCBMSCs) for myocardium in rats after MI. MI models were established in rats, which were injected with PBS, BMMSCs, ADMSCs, and UCMSCs. Cardiac function was detected by ultrasonic cardiogram. TTC staining, TUNEL staining, and immunohistochemistry were adopted to determine infarction area, cardiomyocyte apoptosis, and microvascular density (MVD), respectively. Exosomes were derived from BMMSCs, ADMSCs, and UCBMSCs, and identified by morphological observation and CD63 expression detection. Neonatal rat cardiomyocytes (NRCMs) were isolated and cultured with hypoxia, subjected to PBS and exosomes derived from BMMSCs, ADMSCs, and UCMSCs. Flow cytometry and enzyme-linked immunosorbent assay were used to determine NRCM apoptosis and the levels of angiogenesis-related markers (VEGF, bFGF, and HGF). According to ultrasonic cardiogram, BMMSCs, ADMSCs, and UCMSCs facilitated the cardiac function of MI rats. Furthermore, three kinds of MSCs inhibited cardiomyocyte apoptosis, infarction area, and increased MVD. NRCMs treated with exosomes derived from BMMSCs, ADMSCs, and UCMSCs reduced the NRCM apoptosis and promoted angiogenesis by increasing levels of VEGF, bFGF, and HGF. Notably, exosomes from ADMSCs had the most significant effect. On the basis of the results obtained from this study, exosomes derived from BMMSCs, ADMSCs, and UCBMSCs inhibited the cardiomyocyte apoptosis and promoted angiogenesis, thereby improving cardiac function and protecting myocardium. Notably, exosomes from ADMSCs stimulated most of the cardioprotection factors.

Mesenchymal Stem Cells in the Adult Human Liver: Hype or Hope?

Chronic liver diseases constitute a significant economic, social, and biomedical burden. Among commonly adopted approaches, only organ transplantation can radically help patients with end-stage liver pathologies. Cell therapy with hepatocytes as a treatment for chronic liver disease has demonstrated promising results. However, quality human hepatocytes are in short supply. Stem/progenitor cells capable of differentiating into functionally active hepatocytes provide an attractive alternative approach to cell therapy for liver diseases, as well as to liver-tissue engineering, drug screening, and basic research. The application of methods generally used to isolate mesenchymal stem cells (MSCs) and maintain them in culture to human liver tissue provides cells, designated here as liver MSCs. They have much in common with MSCs from other tissues, but differ in two aspects-expression of a range of hepatocyte-specific genes and, possibly, inherent commitment to hepatogenic differentiation. The aim of this review is to analyze data regarding liver MSCs, probably another type of liver stem/progenitor cells different from hepatic stellate cells or so-called hepatic progenitor cells. The review presents an analysis of the phenotypic characteristics of liver MSCs, their differentiation and therapeutic potential, methods for isolating these cells from human liver, and discusses issues of their origin and heterogeneity. Human liver MSCs are a fascinating object of fundamental research with a potential for important practical applications.

In vitro evaluation of magnetite nanoparticles in human mesenchymal stem cells: comparison of different cytotoxicity assays

This work was aimed at defining the suitable test for evaluating Fe₃O₄ NPs cytotoxicity after short-term exposure in human mesenchymal stem cells (hMSCs) using different viability tests, namely NRU, MTT and TB assays, paralleled by cell morphology analyses for cross checking. MTT and NRU data (culture medium with/without hMSCs plus Fe₃O₄NPs) indicated artificial/false increments in cell viability after Fe₃O₄NPs. These observations did not fit with the morphological analyses showing reduced cell density, loss of monolayer features, and morphological alterations at Fe₃O₄NPs ≥50 μg/ml. Fe₃O₄NPs alone induced a substantial increased absorbance at the wavelength required for MTT and NRU. A significant death (25%) of hMSC at Fe₃O₄NPs ≥10 μg/ml, with a maximum effect (45%) at 300 μg/ml after 24 h, exacerbated after 48 h, was observed when applying TB test. These results paralleled the effects on cell morphology. The optical properties and stability of Fe₃O₄NP suspension (tendency to agglomerate in a specific culture medium) represent factors that limit in vitro result interpretation. These findings suggest the non applicability of the spectrophotometric assays for hMSC culture conditions, while TB is an accurate method for determining cell viability after Fe₃O₄NP exposure in this model. In relation to NPs safety assessment: cell-based assays must be considered on case-by-case basis; selection of relevant cell models is also important for predictive toxicological studies; application of a testing strategy is fundamental for understanding the toxicity pathways driving cellular responses.

In vitro toxicity screening of magnetite nanoparticles by applying mesenchymal stem cells derived from human umbilical cord lining

Despite the growing interest in nanoparticles (NPs), their toxicity has not yet been defined and the development of new strategies and predictive models are required. Human stem cells (SCs) offer a promising and innovative cell-based model. Among SCs, mesenchymal SCs (MSCs) derived from cord lining membrane (CL) may represent a new species-specific tool for establishing efficient platforms for primary screening and toxicity/safety testing of NPs. Superparamagnetic iron oxide NPs, including magnetite (Fe₃ O₄ NPs), have aroused great public health and scientific concerns despite their extensive uses. In this study, CL-MSCs were characterized and applied for in vitro toxicity screening of Fe₃ O₄ NPs. Cytotoxicity, internalization/uptake, differentiation and proliferative capacity were evaluated after exposure to different Fe₃ O₄ NP concentrations. Data were compared with those obtained from bone marrow (BM)-MSCs. We observed, at early passages (P3), that: (1) cytotoxicity occurred at 10 μg/mL in CL-MSCs and 100 μg/mL in BM-MSCs (no differences in toxicity, between CL- and BM-MSCs, were observed at higher dosage, 100-300 μg/mL); (2) cell density decrease and monolayer features loss were affected at ≥50 μg/mL in CL-MSCs only; and (3) NP uptake was concentration-dependent in both MSCs. After 100 μg/mL Fe₃ O₄ NP exposures, the capacity of proliferation was decreased (P5-P9) in CL-MSCs without morphology alteration. Moreover, a progressive decrease of intracellular Fe₃ O₄ NPs was observed over culture time. Antigen surface expression and multilineage differentiation were not influenced. These findings suggest that CL-MSCs could be used as a reliable cell-based model for Fe₃ O₄ NP toxicity screening evaluation and support the use of this approach for improving the confidence degree on the safety of NPs to predict health outcomes.

Accumulating Transcriptome Drift Precedes Cell Aging in Human Umbilical Cord-Derived Mesenchymal Stromal Cells Serially Cultured to Replicative Senescence

In preclinical studies, mesenchymal stromal cells (MSCs) exhibit robust potential for numerous applications. To capitalize on these benefits, cell manufacturing and delivery protocols have been scaled up to facilitate clinical trials without adequately addressing the impact of these processes on cell utility nor inevitable regulatory requirements for consistency. Growing evidence indicates that culture-aged MSCs, expanded to the limits of replicative exhaustion to generate human doses, are not equivalent to early passage cells, and their use may underpin reportedly underwhelming or inconsistent clinical outcomes. Here, we sought to define the maximum expansion boundaries for human umbilical cord-derived MSCs, cultured in chemically defined xeno- and serum-free media, that yield consistent cell batches comparable to early passage cells. Two male and two female donor populations, recovered from cryostorage at mean population doubling level (mPDL) 10, were serially cultivated until replicative exhaustion (senescence). At each passage, growth kinetics, cell morphology, and transcriptome profiles were analyzed. All MSC populations displayed comparable growth trajectories through passage 9 (P9; mPDL 45) and variably approached senescence after P10 (mPDL 49). Transcription profiles of 14,500 human genes, generated by microarray, revealed a nonlinear evolution of culture-adapted MSCs. Significant expression changes occurred only after P5 (mPDL 27) and accumulated rapidly after P9 (mPDL 45), preceding other cell aging metrics. We report that cryobanked umbilical cord-derived MSCs can be reliably expanded to clinical human doses by P4 (mPDL 23), before significant transcriptome drift, and thus represent a mesenchymal cell source suited for clinical translation of cellular therapies. Stem Cells Translational Medicine 2019;8:945&958.

Differences in the intrinsic chondrogenic potential of equine umbilical cord matrix and cord blood mesenchymal stromal/stem cells for cartilage regeneration

Umbilical cord blood mesenchymal stromal/stem cells (UCB-MSCs) and umbilical cord matrix MSCs (UCM-MSCs) have chondrogenic potential and are alternative sources to standard surgically derived bone marrow or adipose tissue collection for cartilage engineering. However, the majority of comparative studies explore neonatal MSCs potential only on ISCT benchmark assays accounting for some bias in the reproducibility between in vitro and in clinical studies. Therefore, we characterized equine UCB-MSCs and UCM-MSCs and investigated with particular attention their chondrogenesis potential in 3D culture with BMP-2 + TGF-ß1 in normoxia or hypoxia. We carried out an exhaustive characterization of the extracellular matrix generated by both these two types of MSCs after the induction of chondrogenesis through evaluation of hyaline cartilage, hypertrophic and osteogenic markers (mRNA, protein and histology levels). Some differences in hypoxia sensitivity and chondrogenesis were observed. UCB-MSCs differentiated into chondrocytes express an abundant, dense and a hyaline-like cartilage matrix. By contrast, despite their expression of cartilage markers, UCM-MSCs failed to express a relevant cartilage matrix after chondrogenic induction. Both MSCs types also displayed intrinsic differences at their undifferentiated basal status, UCB-MSCs expressing higher levels of chondrogenic markers whereas UCM-MSCs synthesizing higher amounts of osteogenic markers. Our results suggest that UCB-MSCs should be preferred for ex-vivo horse cartilage engineering. How those results should be translated to in vivo direct cartilage regeneration remains to be determined through dedicated study.

Mesenchymal Stem Cell Therapy for Bone Regeneration

Mesenchymal stem cells (MSCs) have been used in clinic for approximately 20 years. During this period, various new populations of MSCs have been found or manipulated. However, their characters and relative strength for bone regeneration have not been well known. For a comprehensive understanding of MSCs, we reviewed the literature on the multipotent cells ranging from the definition to the current research progress for bone regeneration. Based on our literature review, bone marrow MSCs have been most widely studied and utilized in clinical settings. Among other populations of MSCs, adipose-derived MSCs and perivascular MSCs might be potential candidates for bone regeneration, whose efficacy and safety still require further investigation.

Current Status of Canine Umbilical Cord Blood-Derived Mesenchymal Stem Cells in Veterinary Medicine

Stem cell therapy has prompted the expansion of veterinary medicine both experimentally and clinically, with the potential to contribute to contemporary treatment strategies for various diseases and conditions for which limited or no therapeutic options are presently available. Although the application of various types of stem cells, such as bone marrow-derived mesenchymal stem cells (BM-MSCs), adipose tissue-derived mesenchymal stem cells (AT-MSCs), and umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs), has promising potential to improve the health of different species, it is crucial that the benefits and drawbacks are completely evaluated before use. Umbilical cord blood (UCB) is a rich source of stem cells; nonetheless, isolation of mesenchymal stem cells (MSCs) from UCB presents technical challenges. Although MSCs have been isolated from UCB of diverse species such as human, equine, sheep, goat, and canine, there are inherent limitations of using UCB from these species for the expansion of MSCs. In this review, we investigated canine UCB (cUCB) and compared it with UCB from other species by reviewing recent articles published from February 2003 to June 2017 to gain an understanding of the limitations of cUCB in the acquisition of MSCs and to determine other suitable sources for the isolation of MSCs from canine. Our review indicates that cUCB is not an ideal source of MSCs because of insufficient volume and ethical issues. However, canine reproductive organs discarded during neutering may help broaden our understanding of effective isolation of MSCs. We recommend exploring canine reproductive and adipose tissue rather than UCB to fulfill the current need in veterinary medicine for the well-designed and ethically approved source of MSCs.

Lower Senescence of Adipose-Derived Stem Cells than Donor-Matched Bone Marrow Stem Cells for Surgical Ventricular Restoration

Surgical ventricular reconstruction (SVR) can restore cardiac function for left ventricular aneurysm to some extent. However, the patches used in this treatment have some limitations such as stiffness and calcification. Engineering heart tissues (EHTs) have emerged as a promising biomaterial to repair damaged heart. Nevertheless, selecting optimal candidate cells for EHTs has been controversial. Aging is a major consideration for seed cells derived from elderly patients. Hence, this study was aimed to assess the proliferation of, antiapoptosis potential of, and expression of senescence-associated factors (eg, SA-β-Gal, cyclin-dependent kinase inhibitor 2A (P16), cyclin-dependent kinase inhibitor 1 (P21) in adipose-derived stem cells (ADSCs), and bone marrow stem cells (BMSCs) in vitro. In addition, cardiac function, cell survival, and angiogenesis of ADSCs and BMSCs after SVR were assessed in vivo. The in vitro results showed that old ADSCs (OAs) grew faster; expressed lower levels of SA-β-Gal, P16, and P21; and possessed more pronounced antiapoptosis activity than old BMSCs (OBs). The in vivo results demonstrated that 28 days after patch implantation, animals that received OAs patches showed better restoration of cardiac function than animals that received OBs patches. Meanwhile, old ADSCs possessed more potential regarding cell survival and angiogenesis. These results suggest that ADSCs may be superior to BMSCs with regard to autologous cell transplantation in elderly patients.

Isolation of human mesenchymal stem cells from amnion, chorion, placental decidua and umbilical cord: comparison of four enzymatic protocols

OBJECTIVE

To compare four enzymatic protocols for mesenchymal stem cells (MSCs) isolation from amniotic (A-MSC) and chorionic (C-MSC) membranes, umbilical cord (UC-MSC) and placental decidua (D-MSC) in order to define a robust, practical and low-cost protocol for each tissue.

RESULTS

A-MSCs and UC-MSCs could be isolated from all samples using trypsin/collagenase-based protocols; C-MSCs could be isolated from all samples with collagenase- and trypsin/collagenase-based protocols; D-MSCs were isolated from all samples exclusively with a collagenase-based protocol.

CONCLUSIONS

The trypsin-only protocol was least efficient; the collagenase-only protocol was best for C-MSCs and D-MSCs; the combination of trypsin and collagenase was best for UC-MSCs and none of tested protocols was adequate for A-MSCs isolation.

Differential Expression of Cholinergic System Components in Human Induced Pluripotent Stem Cells, Bone Marrow-Derived Multipotent Stromal Cells, and Induced Pluripotent Stem Cell-Derived Multipotent Stromal Cells

The components of the cholinergic system are evolutionary very old and conserved molecules that are expressed in typical spatiotemporal patterns. They are involved in signaling in the nervous system, whereas their functions in nonneuronal tissues are hardly understood. Stem cells present an attractive cellular system to address functional issues. This study therefore compared human induced pluripotent stem cells (iPSCs; from cord blood endothelial cells), mesenchymal stromal cells derived from iPSCs (iPSC-MSCs), and bone marrow-derived MSCs (BM-MSCs) from up to 33 different human donors with respect to gene expressions of components of the cholinergic system. The status of cells was identified and characterized by the detection of cell surface antigens using flow cytometry. Acetylcholinesterase expression in iPSCs declined during their differentiation into MSCs and was comparably low in BM-MSCs. Butyrylcholinesterase was present in iPSCs, increased upon transition from the three-dimensional embryoid body phase into monolayer culture, and declined upon further differentiation into iPSC-MSCs. In BM-MSCs a notable butyrylcholinesterase expression could be detected in only four donors, but was elusive in other patient-derived samples. Different nicotinic acetylcholine receptor subunits were preferentially expressed in iPSCs and during early differentiation into iPSC-MSCs, low expression was detected in iPS-MSCs and in BM-MSCs. The m2 and m3 variants of muscarinic acetylcholine receptors were detected in all stem cell populations. In BM-MSCs, these gene expressions varied between donors. Together, these data reveal the differential expression of cholinergic signaling system components in stem cells from specific sources and suggest the utility of our approach to establish informative biomarkers.

No Identical "Mesenchymal Stem Cells" at Different Times and Sites: Human Committed Progenitors of Distinct Origin and Differentiation Potential Are Incorporated as Adventitial Cells in Microvessels

A widely shared view reads that mesenchymal stem/stromal cells (“MSCs”) are ubiquitous in human connective tissues, can be defined by a common in vitro phenotype, share a skeletogenic potential as assessed by in vitro differentiation assays, and coincide with ubiquitous pericytes. Using stringent in vivo differentiation assays and transcriptome analysis, we show that human cell populations from different anatomical sources, regarded as “MSCs” based on these criteria and assumptions, actually differ widely in their transcriptomic signature and in vivo differentiation potential. In contrast, they share the capacity to guide the assembly of functional microvessels in vivo, regardless of their anatomical source, or in situ identity as perivascular or circulating cells. This analysis reveals that muscle pericytes, which are not spontaneously osteochondrogenic as previously claimed, may indeed coincide with an ectopic perivascular subset of committed myogenic cells similar to satellite cells. Cord blood-derived stromal cells, on the other hand, display the unique capacity to form cartilage in vivo spontaneously, in addition to an assayable osteogenic capacity. These data suggest the need to revise current misconceptions on the origin and function of so-called “MSCs,” with important applicative implications. The data also support the view that rather than a uniform class of “MSCs,” different mesoderm derivatives include distinct classes of tissue-specific committed progenitors, possibly of different developmental origin.

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CD146⁺ “MSCs” from different tissues exhibit different transcriptional profiles

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CD146⁺ “MSCs” from different tissues have different differentiation capacities

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CD146⁺ “MSCs” from different tissues organize blood vessels and become pericytes

Coculture of mesenchymal stem cells and endothelial cells enhances host tissue integration and epidermis maturation through AKT activation in gelatin methacryloyl hydrogel-based skin model

A major challenge for clinical use of skin substitutes is insufficient host tissue integration leading to loosening and partial necrosis of the implant. In this present study, a three-dimensional (3D) coculture system constructed using human umbilical cord mesenchymal stem cells (uc-MSCs) and umbilical vein endothelial cells (HUVECs) encapsulated in gelatin methacryloyl (GelMA) hydrogels was evaluated to determine the outcomes of cell-cell interactions in vitro and in vivo. The results revealed that GelMA hydrogels displayed minor cytotoxicity on both cell types. An uc-MSC:HUVEC ratio of 50:50 demonstrated the highest cell proliferation and expression of angiogenic markers. The supplement of basic fibroblast growth factors (bFGF) in coculture system further induced cell proliferation and gene expression in vitro. In vivo transplantation of this cocultured constructs efficiently enhanced the implant and host tissue integration. Additionally, the proliferation of keratinocytes was well maintained on GelMA hydrogels and the gene expression related to cell proliferation and differentiation was significantly increased in coculture system comparing to monoculture. Mechanistically, AKT signaling pathways were activated in cocultures. Our findings suggest that coculturing MSC and EC in GelMA hydrogels could be a promising approach to substantially improve the integration of exogenous skin substitutes and host tissues.

STATEMENT OF SIGNIFICANCE

In this study, the co-culture of uc-MSCs and HUVECs in photocrosslinkable GelMA hydrogels significantly enhanced host tissue integration. Cell proliferation, ECM deposition and angiogenic genes expression were all substantially improved in vitro and the excellent host tissue integration into the implanted tissue was observed in vivo. When served as a dermal layer, the scaffold with co-cultured cells enhanced the proliferation and differentiation of keratinocytes. AKT signaling was proved to be involved in the regulation of cell survival and fate determination. This work demonstrated the importance of 3D cell co-culture to facilitate host tissue integration that can be a promising approach for long-term survival of skin substitutes.

Hox genes in the adult skeleton: Novel functions beyond embryonic development

Hox genes encode evolutionarily conserved transcription factors that control skeletal patterning in the developing embryo. They are expressed in regionally restricted domains and function to regulate the morphology of specific vertebral and long bone elements. Recent work has provided evidence that Hox genes continue to be regionally expressed in adult tissues. Fibroblasts cultured from adult tissues show broadly maintained Hox gene expression patterns. In the adult skeleton, Hox genes are expressed in progenitor-enriched populations of mesenchymal stem/stromal cells (MSCs), and genetic loss-of-function analyses have provided evidence that Hox genes function during the fracture healing process. This review will highlight our current understanding of Hox expression in the adult animal and its function in skeletal regeneration. Developmental Dynamics 246:310-317, 2017. © 2016 Wiley Periodicals, Inc.

Immunophenotyping Reveals the Diversity of Human Dental Pulp Mesenchymal Stromal Cells In vivo and Their Evolution upon In vitro Amplification

Mesenchymal stromal/stem cells (MSCs) from human dental pulp (DP) can be expanded in vitro for cell-based and regenerative dentistry therapeutic purposes. However, their heterogeneity may be a hurdle to the achievement of reproducible and predictable therapeutic outcomes. To get a better knowledge about this heterogeneity, we designed a flow cytometric strategy to analyze the phenotype of DP cells in vivo and upon in vitro expansion with stem cell markers. We focused on the CD31⁻ cell population to exclude endothelial and leukocytic cells. Results showed that the in vivo CD31⁻ DP cell population contained 1.4% of CD56⁺, 1.5% of CD146⁺, 2.4% of CD271⁺ and 6.3% of MSCA-1⁺ cells but very few Stro-1⁺ cells (≤ 1%). CD56⁺, CD146⁺, CD271⁺, and MSCA-1⁺ cell subpopulations expressed various levels of these markers. CD146⁺MSCA-1⁺, CD271⁺MSCA-1⁺, and CD146⁺CD271⁺ cells were the most abundant DP-MSC populations. Analysis of DP-MSCs expanded in vitro with a medicinal manufacturing approach showed that CD146 was expressed by about 50% of CD56⁺, CD271⁺, MSCA-1⁺, and Stro-1⁺ cells, and MSCA-1 by 15–30% of CD56⁺, CD146⁺, CD271⁺, and Stro-1⁺ cells. These ratios remained stable with passages. CD271 and Stro-1 were expressed by <1% of the expanded cell populations. Interestingly, the percentage of CD56⁺ cells strongly increased from P1 (25%) to P4 (80%) both in all sub-populations studied. CD146⁺CD56⁺, MSCA-1⁺CD56⁺, and CD146⁺MSCA-1⁺ cells were the most abundant DP-MSCs at the end of P4. These results established that DP-MSCs constitute a heterogeneous mixture of cells in pulp tissue in vivo and in culture, and that their phenotype is modified upon in vitro expansion. Further studies are needed to determine whether co-expression of specific MSC markers confers DP cells specific properties that could be used for the regeneration of human tissues, including the dental pulp, with standardized cell-based medicinal products.

Comparative study of allogenic and xenogeneic mesenchymal stem cells on cisplatin-induced acute kidney injury in Sprague-Dawley rats

Background

The paracrine and regenerative activities of mesenchymal stem cells (MSCs) may vary with different stem cell sources. The aim of the present study is to compare the effects of MSCs from different sources on acute kidney injury (AKI) induced by cisplatin and their influence on renal regeneration.

Methods

A single intraperitoneal injection of cisplatin (5 mg/kg) was used to induce AKI in 120 Sprague-Dawley rats. Rats were treated with either rat bone marrow stem cells (rBMSCs), human adipose tissue-derived stem cells (hADSCs), or human amniotic fluid-derived stem cells (hAFSCs). 5 × 10⁶ MSCs of different sources were administered through rat tail vein in a single dose, 24 hours after cisplatin injection. Within each group, rats were sacrificed at the 4th, 7th, 11th, and 30th day after cisplatin injection. Serum creatinine, BUN, and renal tissue oxidative stress parameters were measured. Renal tissue was scored histopathologically for evidence of injury, regeneration, and chronicity. Immunohistochemistry was also done using Ki67 for renal proliferative activity evaluation.

Results

MSCs of the three sources were able to ameliorate cisplatin-induced renal function deterioration and tissue damage. The rat BMSCs-treated group had the lowest serum creatinine by day 30 (0.52 ± 0.06) compared to hADSCs and hAFSCs. All MSC-treated groups had nearly equal antioxidant activity as indicated by the decreased renal tissue malondialdehyde (MDA) and increased reduced glutathione (GSH) level and superoxide dismutase (SOD) activity at different time intervals. Additionally, all MSCs improved injury and regenerative scores. Rat BMSCs had the highest count and earliest proliferative activity in the renal cortex by day 7 as identified by Ki67; while, hAFSCs seem to have the greatest improvement in the regenerative and proliferative activities with a higher count of renal cortex Ki67-positive cells at day 11 and with the least necrotic lesions.

Conclusions

Rat BMSCs, hADSCs, and hAFSCs, in early single IV dose, had a renoprotective effect against cisplatin-induced AKI, and were able to reduce oxidative stress markers. Rat BMSCs had the earliest proliferative activity by day 7; however, hAFSCs seemed to have the greatest improvement in the regenerative activities. Human ADSCs were the least effective in the terms of proliferative and regenerative activities.

Expression of neural cell adhesion molecule and polysialic acid in human bone marrow-derived mesenchymal stromal cells

BACKGROUND

In order to develop novel clinical applications and to gain insights into possible therapeutic mechanisms, detailed molecular characterization of human bone marrow-derived mesenchymal stromal cells (hBM-MSCs) is needed. Neural cell adhesion molecule (NCAM, CD56) is a transmembrane glycoprotein modulating cell-cell and cell-matrix interactions. An additional post-translational modification of NCAM is the α2,8-linked polysialic acid (polySia). Because of its background, NCAM is often considered a marker of neural lineage commitment. Generally, hBM-MSCs are considered to be devoid of NCAM expression, but more rigorous characterization is needed.

METHODS

We have studied NCAM and polySia expression in five hBM-MSC lines at mRNA and protein levels. Cell surface localization was confirmed by immunofluorescence staining and expression frequency in the donor-specific lines by flow cytometry. For the detection of poorly immunogenic polySia, a fluorochrome-tagged catalytically defective enzyme was employed.

RESULTS

All five known NCAM isoforms are expressed in these cells at mRNA level and the three main isoforms are present at protein level. Both polysialyltransferases, generally responsible for NCAM polysialylation, are expressed at mRNA level, but only very few cells express polySia at the cell surface.

CONCLUSIONS

Our results underline the need for a careful control of methods and conditions in the characterization of MSCs. This study shows that, against the generally held view, clinical-grade hBM-MSCs do express NCAM. In contrast, although both polysialyltransferase genes are transcribed in these cells, very few express polySia at the cell surface. NCAM and polySia represent new candidate molecules for influencing MSC interactions.

The effect of fibroblast growth factor on distinct differentiation potential of cord blood-derived unrestricted somatic stem cells and Wharton's jelly-derived mesenchymal stem/stromal cells

BACKGROUND AIMS

Perinatal tissues are considered an attractive source of mesenchymal stem/stromal cells (MSCs) and have unique characteristics depending on their origin. In this study, we compared the basic characteristics of unrestricted somatic stem cells isolated from cord blood (CB-USSCs) and MSCs isolated from Wharton's jelly of umbilical cords (WJ-MSCs). We also evaluated the effect of basic fibroblast growth factor (bFGF) supplementation on the growth and differentiation of these cells.

METHODS

CB-USSCs and WJ-MSCs were isolated from the same individual (n = 6), and their morphology, cell surface antigens, proliferation, expression of stemness markers and adipogenic, osteogenic and chondrogenic differentiation potentials were evaluated. Their morphology, proliferation and differentiation potentials were then also compared in the presence of bFGF supplementation (10 ng/mL).

RESULTS

Overall, CB-USSCs expressed DLK-1 and negative for all the HOX gene markers. The expression of cell surface antigen CD90, growth capacity and adipogenic differential potential of CB-USSCs were lower than those of WJ-MSCs. WJ-MSCs showed higher growth capacity, but the expression of CD73 and CD105 and their osteogenic differentiation potential were lower than those of CB-USSCs. The spindle morphology of both CB-USSCs and WJ-MSCs and the growth and adipogenic differentiation of CB-USSCs were improved by bFGF supplementation. However, the bFGF supplement did not have any positive effect on the tri-lineage differentiation potentials of WJ-MSCs.

CONCLUSIONS

CB-USSCs and WJ-MSCs each had distinct characteristics including different growth capacity, distinguishable cell surface markers and distinct adipogenic and osteogenic potentials. bFGF supplementation improved the growth capacity and adipogenic differentiation of CB-USSCs.

Low oxygen tension reveals distinct HOX codes in human cord blood-derived stromal cells associated with specific endochondral ossification capacities in vitro and in vivo

Effects of oxygen tension on the generation, expansion, proliferation and differentiation of stromal cell types is widely described in the literature. However, data on the internal heterogeneity of applied cell populations at different O₂ levels and possible impacts on differentiation potentials are controversial. Here, the expression of 39 human HOX genes was determined in neonatal cord blood stromal cells and linked to differentiation-associated signatures. In cord blood, unrestricted somatic stromal cells (USSCs), lacking HOX gene expression, and cord blood-derived multipotent stromal cells (CB-MSCs), expressing about 20 HOX genes, are distinguished by their specific HOX code. Interestingly, 74% of the clones generated at 21% O₂ were HOX-negative USSCs, whereas 73% of upcoming clones at 3% O₂ were HOX-positive CB-MSCs. In order to better categorize distinct cell lines generated at 3% O₂ , the expression of all 39 HOX genes within HOX clusters A, B, C and D were tested and new subtypes defined: cells negative in all four HOX clusters (USSCs); cells positive in all four clusters (CB-MSCs^ABCD ); and subpopulations missing a single cluster (CB-MSCs^ACD and CB-MSCs^BCD ). Comprehensive qPCR analyses of established chondro-osteomarkers revealed subtype-specific signatures verifiably associated with in vitro and in vivo differentiation capacity. The data presented here underline the necessity of better characterizing distinct cell populations at a clonal level, taking advantage of the inherent specific HOX code as a distinguishing feature between individual subtypes. Moreover, the correlation of subtype-specific molecular signatures with in vitro and in vivo bone formation is discussed. Copyright © 2016 John Wiley & Sons, Ltd.

Comparison of in vitro-cultivation of human mesenchymal stroma/stem cells derived from bone marrow and umbilical cord

Cell-mediated therapy is currently considered as a novel approach for many human diseases. Potential uses range from topic applications with the regeneration of confined tissue areas to systemic applications. Stem cells including mesenchymal stroma/stem cells (MSCs) represent a highly attractive option. Their potential to cure or alleviate human diseases is investigated in a number of clinical trials. A wide variety of methods has been established in the past years for isolation, cultivation and characterization of human MSCs as expansion is presently deemed a prerequisite for clinical application with high numbers of cells carrying reproducible properties. MSCs have been retrieved from various tissues and used in a multitude of settings whereby numerous experimental protocols are available for expansion of MSCs in vitro. Accordingly, different isolation, culture and upscaling techniques contribute to the heterogeneity of MSC characteristics and the, sometimes, controversial results. Therefore, this review discusses and summarizes certain experimental conditions for MSC in vitro culture focusing on adult bone marrow-derived and neonatal umbilical cord-derived MSCs in order to enhance our understanding for MSC tissue sources and to stratify different procedures. Copyright © 2016 John Wiley & Sons, Ltd.

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.

Genetic Comparison of Stemness of Human Umbilical Cord and Dental Pulp

This study focuses on gene expression patterns and functions in human umbilical cord (UC) and dental pulp (DP) containing mesenchymal stem cells (MSCs). DP tissues were collected from 25 permanent premolars. UC tissue samples were obtained from three newborns. Comparative gene profiles were obtained using cDNA microarray analysis and the expression of tooth development-associated and MSC-related genes was assessed by the quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). Genes related to cell proliferation, angiogenesis, and immune responses were expressed at higher levels in UC, whereas genes related to growth factor and receptor activity and signal transduction were more highly expressed in DP. Although UC and DP tissues exhibited similar expression of surface markers for MSCs, UC showed higher expression of CD29, CD34, CD44, CD73, CD105, CD146, and CD166. qRT-PCR analysis showed that CD146, CD166, and MYC were expressed 18.3, 8.24, and 1.63 times more highly in UC, whereas the expression of CD34 was 2.15 times higher in DP. Immunohistochemical staining revealed significant differences in the expression of genes (DSPP, DMP1, and CALB1) related to odontogenesis and angiogenesis in DP. DP and UC tissue showed similar gene expression, with the usual MSC markers, while they clearly diverged in their differentiation capacity.

Activation of the Extracellular Signal-Regulated Kinase Signaling Is Critical for Human Umbilical Cord Mesenchymal Stem Cell Osteogenic Differentiation

Human umbilical cord mesenchymal stem cells (hUCMSCs) are recognized as candidate progenitor cells for bone regeneration. However, the mechanism of hUCMSC osteogenesis remains unclear. In this study, we revealed that mitogen-activated protein kinases (MAPKs) signaling is involved in hUCMSC osteogenic differentiation in vitro. Particularly, the activation of c-Jun N-terminal kinases (JNK) and p38 signaling pathways maintained a consistent level in hUCMSCs through the entire 21-day osteogenic differentiation period. At the same time, the activation of extracellular signal-regulated kinases (ERK) signaling significantly increased from day 5, peaked at day 9, and declined thereafter. Moreover, gene profiling of osteogenic markers, alkaline phosphatase (ALP) activity measurement, and alizarin red staining demonstrated that the application of U0126, a specific inhibitor for ERK activation, completely prohibited hUCMSC osteogenic differentiation. However, when U0126 was removed from the culture at day 9, ERK activation and osteogenic differentiation of hUCMSCs were partially recovered. Together, these findings demonstrate that the activation of ERK signaling is essential for hUCMSC osteogenic differentiation, which points out the significance of ERK signaling pathway to regulate the osteogenic differentiation of hUCMSCs as an alternative cell source for bone tissue engineering.

Direct Comparison of Wharton's Jelly and Bone Marrow-Derived Mesenchymal Stromal Cells to Enhance Engraftment of Cord Blood CD34(+) Transplants

Cotransplantation of CD34(+) hematopoietic stem and progenitor cells (HSPCs) with mesenchymal stromal cells (MSCs) enhances HSPC engraftment. For these applications, MSCs are mostly obtained from bone marrow (BM). However, MSCs can also be isolated from the Wharton's jelly (WJ) of the human umbilical cord. This source, regarded to be a waste product, enables a relatively low-cost MSC acquisition without any burden to the donor. In this study, we evaluated the ability of WJ MSCs to enhance HSPC engraftment. First, we compared cultured human WJ MSCs with human BM-derived MSCs (BM MSCs) for in vitro marker expression, immunomodulatory capacity, and differentiation into three mesenchymal lineages. Although we confirmed that WJ MSCs have a more restricted differentiation capacity, both WJ MSCs and BM MSCs expressed similar levels of surface markers and exhibited similar immune inhibitory capacities. Most importantly, cotransplantation of either WJ MSCs or BM MSCs with CB CD34(+) cells into NOD SCID mice showed similar enhanced recovery of human platelets and CD45(+) cells in the peripheral blood and a 3-fold higher engraftment in the BM, blood, and spleen 6 weeks after transplantation when compared to transplantation of CD34(+) cells alone. Upon coincubation, both MSC sources increased the expression of adhesion molecules on CD34(+) cells, although stromal cell-derived factor-1 (SDF-1)-induced migration of CD34(+) cells remained unaltered. Interestingly, there was an increase in CFU-GEMM when CB CD34(+) cells were cultured on monolayers of WJ MSCs in the presence of exogenous thrombopoietin, and an increase in BFU-E when BM MSCs replaced WJ MSCs in such cultures. Our results suggest that WJ MSC is likely to be a practical alternative for BM MSC to enhance CB CD34(+) cell engraftment.

Freezing of Fresh Wharton's Jelly From Human Umbilical Cords Yields High Post-Thaw Mesenchymal Stem Cell Numbers for Cell-Based Therapies

Some cord blood banks freeze entire pieces of UC (mixed cord, MC) which after post-thaw yields mixed heterogeneous populations of mesenchymal stem cells (MSCs) from all its microanatomical compartments. Freezing of such entire tissues results in sub-optimal post-thaw cell recovery because of poor cryoprotectant diffusion and intracellular ice-formation, heat and water transport issues, and damage to intercellular junctions. To develop a simple method of harvesting pure homogeneous MSCs for cord blood banks, we compared the post-thaw behavior of three groups of frozen UC tissues: (i) freshly harvested WJ without cell separation; (ii) MSCs isolated from WJ (WJSC); and (iii) MC, WJ, and WJSC produced high post-thaw cell survival rates (93.52 ± 6.12% to 90.83 ± 4.51%) and epithelioid monolayers within 24 h in primary culture whereas post-thaw MC explants showed slow growth with mixed epithelioid and fibroblastic cell outgrowths after several days. Viability and proliferation rates of post-thawed WJ and hWJSC were significantly greater than MC. Post-thaw WJ and WJSC produced significantly greater CD24(+) and CD108(+) fluorescence intensities and significantly lower CD40(+) contaminants. Post-thaw WJ and WJSC produced significantly lesser annexin-V-positive and sub-G1 cells and greater degrees of osteogenic and chondrogenic differentiation compared to MC. qRT-PCR analysis of post-thaw MC showed significant decreases in anti-apoptotic gene expression (SURVIVIN, BCL2) and increases in pro-apoptotic (BAX) and cell cycle regulator genes (P53, P21, ROCK 1) compared to WJ and WJSC. We conclude that freezing of fresh WJ is a simple and reliable method of generating large numbers of clinically utilizable MSCs for cell-based therapies.

Differential properties of human stromal cells from bone marrow, adipose, liver and cardiac tissues

BACKGROUND AIMS

Mesenchymal stromal cells (MSCs), derived from several tissues including bone marrow and adipose tissue, are being evaluated in clinical trials for a range of diseases. Virtually all tissues of the body contain stromal cells, yet it is unknown whether these sources are similar in phenotype and function.

METHODS

We have isolated stromal cells from several human tissues including bone marrow (BM-MSCs), heart (heart stroma, HS), adipose (adipose stroma, AS) and liver (liver stroma, LS) and compared the morphology, phenotype and functional properties of these stromal cell populations.

RESULTS

The cellular phenotype of each population was identical, namely, CD105+, CD73+, CD90+, CD34- and CD45-. In addition, morphology and differentiation potential were comparable. Co-culture studies revealed similar supportive potential of BM-MSCs, AS and LS with hematopoietic cells or tumor cells. In contrast, significant inhibition of proliferation of both cells types was obtained with HS, with significant loss of viability with tumor cells, demonstrating a unique functional property of HS with regard to tumor cell proliferation.

CONCLUSIONS

Although stromal cells from different tissues have similar morphology and phenotype, their functional properties vary, requiring critical evaluation of stromal cells before use in non-homologous settings. HS may play a key role in inhibiting proliferation of tumor cells in the heart, providing the reason for the low occurrence of tumor development. Given the tumor-supportive property of BM-MSCs and AS, the use of these cells in cardiac tissue may result in replacement of a tumor-inhibitory stroma with a tumor-supportive microenvironment.

Comparative studies of mesenchymal stem cells derived from different cord tissue compartments - The influence of cryopreservation and growth media

INTRODUCTION

We have identified some critical aspects concerning umbilical cord tissue mesenchymal stem cells: the lack of standards for cell isolation, expansion and cryopreservation, the lack of unanimous opinions upon their multilineage differentiation potential and the existence of very few results related to the functional characterization of the cells isolated from cryopreserved umbilical cord tissue. Umbilical cord tissue cryopreservation appears to be the optimal solution for umbilical cord tissue mesenchymal stem cells storage for future clinical use. Umbilical cord tissue cryopreservation allows mesenchymal stem cells isolation before expected use, according with the specific clinical applications, by different customized isolation and expansion protocols agreed by cell therapy institutions.

METHODS

Using an optimized protocol for umbilical cord tissue cryopreservation in autologous cord blood plasma, isolation explant method and growth media supplemented with FBS or human serum, we performed comparative studies with respect to the characteristics of mesenchymal stem cells (MSC) isolated from different compartments of the same umbilical cord tissue such as Wharton's jelly, vein, arteries, before cryopreservation (pre freeze) and after cryopreservation (post thaw).

RESULTS

Expression of histochemical and immunohistochemical markers as well as electron microscopy observations revealed similar adipogenic, chondrogenic and osteogenic differentiation capacity for cells isolated from pre freeze and corresponding post thaw tissue fragments of Wharton's jelly, vein or arteries of the same umbilical cord tissue, regardless growth media used for cells isolation and expansion.

DISCUSSION

Our efficient umbilical cord tissue cryopreservation protocol is reliable for clinical applicability of mesenchymal stem cells that could next be isolated and expanded in compliance with future accepted standards.

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.

Comparative Characterization of Cells from the Various Compartments of the Human Umbilical Cord Shows that the Wharton's Jelly Compartment Provides the Best Source of Clinically Utilizable Mesenchymal Stem Cells

The human umbilical cord (UC) is an attractive source of mesenchymal stem cells (MSCs) with unique advantages over other MSC sources. They have been isolated from different compartments of the UC but there has been no rigorous comparison to identify the compartment with the best clinical utility. We compared the histology, fresh and cultured cell numbers, morphology, proliferation, viability, stemness characteristics and differentiation potential of cells from the amnion (AM), subamnion (SA), perivascular (PV), Wharton’s jelly (WJ) and mixed cord (MC) of five UCs. The WJ occupied the largest area in the UC from which 4.61 ± 0.57 x 10⁶ /cm fresh cells could be isolated without culture compared to AM, SA, PV and MC that required culture. The WJ and PV had significantly lesser CD40+ non-stem cell contaminants (26-27%) compared to SA, AM and MC (51-70%). Cells from all compartments were proliferative, expressed the typical MSC-CD, HLA, and ESC markers, telomerase, had normal karyotypes and differentiated into adipocyte, chondrocyte and osteocyte lineages. The cells from WJ showed significantly greater CD24+ and CD108+ numbers and fluorescence intensities that discriminate between MSCs and non-stem cell mesenchymal cells, were negative for the fibroblast-specific and activating-proteins (FSP, FAP) and showed greater osteogenic and chondrogenic differentiation potential compared to AM, SA, PV and MC. Cells from the WJ offer the best clinical utility as (i) they have less non-stem cell contaminants (ii) can be generated in large numbers with minimal culture avoiding changes in phenotype, (iii) their derivation is quick and easy to standardize, (iv) they are rich in stemness characteristics and (v) have high differentiation potential. Our results show that when isolating MSCs from the UC, the WJ should be the preferred compartment, and a standardized method of derivation must be used so as to make meaningful comparisons of data between research groups.

DNA damage response in neonatal and adult stromal cells compared with induced pluripotent stem cells

Comprehensive analyses comparing individual DNA damage response (DDR) of induced pluripotent stem cells (iPSCs) with neonatal stromal cells with respect to their developmental age are limited. The imperative necessity of providing developmental age-matched cell sources for meaningful toxicological drug safety assessments in replacement of animal-based testing strategies is evident. Here, DDR after radiation or treatment with N-methyl-N-nitrosurea (MNU) was determined in iPSCs compared with neonatal and bone marrow stromal cells. Neonatal and adult stromal cells showed no significant morphologically detectable cytotoxicity following treatment with 1 Gy or 1 mM MNU, whereas iPSCs revealed a much higher sensitivity. Foci analyses revealed an effective DNA repair in stromal cell types and iPSCs, as reflected by a rapid formation and disappearance of phosphorylated ATM and γH2AX foci. Furthermore, quantitative polymerase chain reaction analyses revealed the highest basic expression level of DDR and repair-associated genes in iPSCs, followed by neonatal stromal cells and adult stromal cells with the lowest expression levels. In addition, the influence of genotoxic stress prior to and during osteogenic differentiation of neonatal and adult stromal cells was analyzed applying common differentiation procedures. Experiments presented here suggest a developmental age-dependent basic expression level of genes involved in the processing of DNA damage. In addition a differentiation-dependent downregulation of repair genes was observed during osteogenesis. These results strongly support the requirement to provide adequate cell sources for toxicological in vitro drug testing strategies that match to the developmental age and differentiation status of the presumptive target cell of interest.

SIGNIFICANCE

The results obtained in this study advance the understanding of DNA damage processing in human neonatal stromal cells as compared with adult stromal cells and induced pluripotent stem cells (iPSCs). The data suggest developmental age-dependent differences in DNA damage repair capacity. In iPSCs (closest to embryonic stem cells), the highest expression level of DNA damage response and repair genes was found, followed by neonatal stromal cells and adult stromal cells with the lowest overall expression. In addition, a differentiation-dependent downregulation of repair capacity was observed during osteogenic differentiation in neonatal stromal cells. Notably, the impact of genotoxic stress on osteogenic differentiation depended on the time the genotoxic insult took place and, moreover, was agent-specific. These results strongly support the necessity of offering and establishing adequate cell sources for informative toxicological testing matching to the developmental age and differentiation status of the respective cell of interest.

Cord blood for brain injury

Recovery from neurological injuries is typically incomplete and often results in significant and permanent disabilities. Currently, most available therapies are limited to supportive or palliative measures, aimed at managing the symptoms of the condition. Because restorative therapies targeting the underlying cause of most neurological diseases do not exist, cell therapies targeting anti-inflammatory, neuroprotective and regenerative potential hold great promise. Cord blood (CB) cells can induce repair through mechanisms that involve trophic or cell-based paracrine effects or cellular integration and differentiation. Both may be operative in emerging CB therapies for neurologic conditions, and there are numerous potential applications of CB-based regenerative therapies in neurological diseases, including genetic diseases of childhood, ischemic events such as stroke and neurodegenerative diseases of adulthood. CB appears to hold promise as an effective therapy for patients with brain injuries. In this Review, we describe the state of science and clinical applications of CB therapy for brain injury.