Impact of aging on the regenerative properties of bone marrow-, muscle-, and adipose-derived mesenchymal stem/stromal cells

Revisiting the Advances in Isolation, Characterization and Secretome of Adipose-Derived Stromal/Stem Cells

Adipose-derived stromal/stem cells (ASCs) seems to be a promising regenerative therapeutic agent due to the minimally invasive approach of their harvest and multi-lineage differentiation potential. The harvested adipose tissues are further digested to extract stromal vascular fraction (SVF), which is cultured, and the anchorage-dependent cells are isolated in order to characterize their stemness, surface markers, and multi-differentiation potential. The differentiation potential of ASCs is directed through manipulating culture medium composition with an introduction of growth factors to obtain the desired cell type. ASCs have been widely studied for its regenerative therapeutic solution to neurologic, skin, wound, muscle, bone, and other disorders. These therapeutic outcomes of ASCs are achieved possibly via autocrine and paracrine effects of their secretome comprising of cytokines, extracellular proteins and RNAs. Therefore, secretome-derivatives might offer huge advantages over cells through their synthesis and storage for long-term use. When considering the therapeutic significance and future prospects of ASCs, this review summarizes the recent developments made in harvesting, isolation, and characterization. Furthermore, this article also provides a deeper insight into secretome of ASCs mediating regenerative efficacy.

Current advances for bone regeneration based on tissue engineering strategies

Bone tissue engineering (BTE) is a rapidly developing strategy for repairing critical-sized bone defects to address the unmet need for bone augmentation and skeletal repair. Effective therapies for bone regeneration primarily require the coordinated combination of innovative scaffolds, seed cells, and biological factors. However, current techniques in bone tissue engineering have not yet reached valid translation into clinical applications because of several limitations, such as weaker osteogenic differentiation, inadequate vascularization of scaffolds, and inefficient growth factor delivery. Therefore, further standardized protocols and innovative measures are required to overcome these shortcomings and facilitate the clinical application of these techniques to enhance bone regeneration. Given the deficiency of comprehensive studies in the development in BTE, our review systematically introduces the new types of biomimetic and bifunctional scaffolds. We describe the cell sources, biology of seed cells, growth factors, vascular development, and the interactions of relevant molecules. Furthermore, we discuss the challenges and perspectives that may propel the direction of future clinical delivery in bone regeneration.

Epiregulin promotes the migration and chemotaxis ability of adipose-derived mesenchymal stem cells via mitogen-activated protein kinase signaling pathways

To investigate the function of epiregulin (EREG) in the migration and chemotaxis ability of mesenchymal stem cells. Adipose-derived stem cells (ADSCs) were used in this investigation. Lentiviral EREG short hairpin RNA was applied to silence EREG expression in ADSCs. Human recombinant EREG protein (rhEREG) was used to perform a gain-of-function study. Scratch-simulated wound migration and transwell chemotaxis assays were used to examine the migration and chemotaxis capacity of ADSCs in vitro. Using a Western blot assay, the expressions of p38 mitogen-activated protein kinase (p38 MAPK), c-Jun N-terminal kinase (JNK), extracellular signal-regulated protein kinases 1 and 2 (Erk1/2), and protein kinase B were detected. Depletion of EREG caused by specific short hairpin RNA restrained the migration and chemotaxis ability of ADSCs and inhibited the expressions of phosphorylated p38 MAPK, JNK, and Erk1/2. rhEREG improved ADSCs migration and chemotaxis capacity, which was repressed by knockdown of EREG and rescued the expressions of phosphorylated p38 MAPK, JNK, and Erk1/2 impaired by silencing EREG. Furthermore, rhEREG-improved migration and chemotaxis ability in EREG-depleted-ADSCs was restricted by a specific inhibitor, SB203580, for blocking p38 MAPK signaling, PD98059 for blocking Erk1/2 signaling, or SP600125 for blocking JNK signaling in ADSCs separately. EREG promotes migration and chemotaxis ability of ADSCs through MAPK signaling pathways.

Stem cell therapy for diabetic foot ulcers: a review of preclinical and clinical research

BACKGROUND

Diabetic foot ulcer (DFU) is a severe complication of diabetes, preceding most diabetes-related amputations. DFUs require over US$9 billion for yearly treatment and are now a global public health issue. DFU occurs in the setting of ischemia, infection, neuropathy, and metabolic disorders that result in poor wound healing and poor treatment options. Recently, stem cell therapy has emerged as a new interventional strategy to treat DFU and appears to be safe and effective in both preclinical and clinical trials. However, variability in the stem cell type and origin, route and protocol for administration, and concomitant use of angioplasty confound easy interpretation and generalization of the results.

METHODS

The PubMed, Google Scholar, and EMBASE databases were searched and 89 preclinical and clinical studies were selected for analysis.

RESULTS

There was divergence between preclinical and clinical studies regarding stem cell type, origin, and delivery techniques. There was heterogeneous preclinical and clinical study design and few randomized clinical trials. Granulocyte-colony stimulating factor was employed in some studies but with differing protocols. Concomitant performance of angioplasty with stem cell therapy showed increased efficiency compared to either therapy alone.

CONCLUSIONS

Stem cell therapy is an effective treatment for diabetic foot ulcers and is currently used as an alternative to amputation for some patients without other options for revascularization. Concordance between preclinical and clinical studies may help design future randomized clinical trials.

Stem Cells in Dentistry: Types of Intra- and Extraoral Tissue-Derived Stem Cells and Clinical Applications

Stem cells are undifferentiated cells, capable of renewing themselves, with the capacity to produce different cell types to regenerate missing tissues and treat diseases. Oral facial tissues have been identified as a source and therapeutic target for stem cells with clinical interest in dentistry. This narrative review report targets on the several extraoral- and intraoral-derived stem cells that can be applied in dentistry. In addition, stem cell origins are suggested in what concerns their ability to differentiate as well as their particular distinguishing quality of convenience and immunomodulatory for regenerative dentistry. The development of bioengineered teeth to replace the patient's missing teeth was also possible because of stem cell technologies. This review will also focus our attention on the clinical application of stem cells in dentistry. In recent years, a variety of articles reported the advantages of stem cell-based procedures in regenerative treatments. The regeneration of lost oral tissue is the target of stem cell research. Owing to the fact that bone imperfections that ensue after tooth loss can result in further bone loss which limit the success of dental implants and prosthodontic therapies, the rehabilitation of alveolar ridge height is prosthodontists' principal interest. The development of bioengineered teeth to replace the patient's missing teeth was also possible because of stem cell technologies. In addition, a “dental stem cell banking” is available for regenerative treatments in the future. The main features of stem cells in the future of dentistry should be understood by clinicians.

Inhibition of the RhoGTPase Cdc42 by ML141 enhances hepatocyte differentiation from human adipose-derived mesenchymal stem cells via the Wnt5a/PI3K/miR-122 pathway: impact of the age of the donor

Background

Human adipose-derived mesenchymal stem cells (hADSCs) are promising cells that may promote hepatocyte differentiation (Hep-Dif) and improve liver function, but the involvement of Cdc42, a key small RhoGTPase which plays a crucial role in aging, is still not well established. We hypothesized that the inhibition of Cdc42 may rescue the hepatogenic potential of hADSCs derived from aged donors.

Methods

hADSCs isolated from 61 women of different ages were cultured for evaluation of the proliferation of cells, adherence, apoptosis, immunomodulation, immunophenotyping, multipotency, gene expression, and cell function during Hep-Dif. Inhibition of Cdc42 by ML141 was realized during two phases: initiation (days –2 to 14 (D–2/14)) from undifferentiated to hepatoblast-like cells, or maturation (days 14 to 28 (D14/28)) from undifferentiated to hepatocyte-like cells. Mechanistic insights of the Wnt(s)/MAPK/PI3K/miR-122 pathways were studied.

Results

Cdc42 activity in undifferentiated hADSCs showed an age-dependent significant increase in Cdc42-GTP correlated to a decrease in Cdc42GAP; the low potentials of cell proliferation, doubling, adherence, and immunomodulatory ability (proinflammatory over anti-inflammatory) contrary to the apoptotic index of the aged group were significantly reversed by ML141. Aged donor cells showed a decreased potential for Hep-Dif which was rescued by ML141 treatment, giving rise to mature and functional hepatocyte-like cells as assessed by hepatic gene expression, cytochrome activity, urea and albumin production, low-density lipoprotein (LDL) uptake, and glycogen storage. ML141-induced Hep-Dif showed an improvement in mesenchymal-epithelial transition, a switch from Wtn-3a/β-catenin to Wnt5a signaling, involvement of PI3K/PKB but not the MAPK (ERK/JNK/p38) pathway, induction of miR-122 expression, reinforcing the exosomes release and the production of albumin, and epigenetic changes. Inhibition of PI3K and miR-122 abolished completely the effects of ML141 indicating that inhibition of Cdc42 promotes the Hep-Dif through a Wnt5a/PI3K/miR-122/HNF4α/albumin/E-cadherin-positive action. The ML141(D–2/14) protocol had more pronounced effects when compared with ML141(D14/28); inhibition of DNA methylation in combination with ML141(D–2/14) showed more efficacy in rescuing the Hep-Dif of aged hADSCs. In addition to Hep-Dif, the multipotency of aged hADSC-treated ML141 was observed by rescuing the adipocyte and neural differentiation by inducing PPARγ/FABP4 and NeuN/O4 but inhibiting Pref-1 and GFAP, respectively.

Conclusion

ML141 has the potential to reverse the age-related aberrations in aged stem cells and promotes their hepatogenic differentiation. Selective inhibition of Cdc42 could be a potential target of drug therapy for aging and may give new insights on the improvement of Hep-Dif.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-0910-5) contains supplementary material, which is available to authorized users.

Adipose-derived and bone marrow mesenchymal stem cells: a donor-matched comparison

Background

Adipose-derived stem cells (ASCs) have been introduced as an alternative to bone marrow mesenchymal stem cells (BMSCs) for cell-based therapy. However, different studies comparing ASCs and BMSCs have shown conflicting results. In fact, harvesting ASCs and BMSCs from different individuals might influence the results, making comparison difficult. Therefore, this study aimed to characterize donor-matched ASCs and BMSCs in order to investigate proliferation, differentiation potential and possible effects of donor variation on these mesenchymal stem cells (MSCs).

Methods

Human bone marrow and adipose tissue samples were obtained from nine donors aged 8–14. ASCs and BMSCs were isolated and characterized based on expression of surface markers using flow cytometry. The proliferation up to 21 days was investigated. Multi-lineage differentiation was induced using osteogenic, chondrogenic and adipogenic differentiation media. Alkaline phosphatase (ALP) activity was monitored and collagen type I formation was evaluated by immunofluorescence staining. In vitro multi-potency was studied using tissue-specific stains and lineage-specific gene expression. In addition, the osteogenic lineage was evaluated at protein level.

Results

Isolated ASCs and BMSCs from all donors demonstrated morphologic and immunophenotypic characteristics of MSCs, with expression of MSCs markers and negative expression of hematopoietic markers. Unlike BMSCs, ASCs showed high expression of CD49d and low expression of Stro-1. In general, ASCs showed significantly higher proliferation and adipogenic capacity with more lipid vesicle formation and expression of the adipogenesis-related genes than BMSCs. In contrast, BMSCs showed significantly higher osteogenic and chondrogenic capacity compared to ASCs. BMSCs had earlier and higher ALP activity, calcium deposition, and expression of the osteogenesis- and chondrogenesis-related genes and the osteogenesis-related protein osteopontin. Proliferation and differentiation capacity of ASCs and BMSCs varied significantly among the donors.

Conclusions

ASCs and BMSCs showed tissue-specific differentiation abilities, but with significant variation between donors. The similarities and differences in the properties of ASCs and BMSCs should be taken into consideration when planning stem cell-based therapy.

Therapeutic efficacy and safety of umbilical cord mesenchymal stem cell transplantation for liver cirrhosis in Chinese population: A meta-analysis

BACKGROUND AND OBJECTIVE

Mesenchymal stem cells transfusion has been considered as a promising option for liver cirrhosis (LC). The aim of this study was to systematically evaluate the efficacy and safety of umbilical cord mesenchymal stem cells (UMSC) combined with traditional supportive therapy (TST) for the treatment of patients with LC.

METHODS

Data was extracted from clinical trials published on Web of Science, PubMed, EMBASE, Cochrane Library, Wanfang and CNKI database. The evaluated outcome measurements included liver function, coagulation function, liver fibrosis indexes, clinical symptoms, quality of life (QOL) and adverse events.

RESULTS

A total of 14 trials including 717 LC patients met our selection criteria were involved. The liver function of LC patients was significantly improved after combined therapy (UMSC plus TST), indicated by decreased total bilirubin, alanine aminotransferase and prothrombin time, and increased serum albumin, cholinesterase and prothrombin activity. The QOL of patients was also improved after UMSC therapy. Compared with TST alone, the combined therapy showed better treatment effect based on measurements of hyaluronic acid (OR=-143.20, CI=-181.58 to -104.82, P<0.00001), laminin (OR=-50.65, CI=-53.70 to -47.61, P<0.00001), type III procollagen (OR=-8.68, CI=-9.00 to -8.36, P<0.00001), type IV collagen (OR=-105.79, CI=-132.44 to -79.14, P<0.00001) and plasma prolidase (OR=-876.54, CI=-911.89 to -840.56, P<0.00001). Moreover, the patients' clinical symptoms including fatigue (4th, P=0.003; 8th, P=0.01), appetite (4th, P<0.0001; 8th, P=0.06), ascites (4th, P=0.03; 8th, P=0.17), and abdominal distension (4th, P=0.0008; 8th, P=0.64) were also improved in patients treated by combined therapy without adverse events observed.

CONCLUSION

UMSC and TST combined therapy for LC patients improved their liver function, clinical symptoms and QOL without severe adverse events, therefore is safe and effective in LC therapy.

Performing a Better Bone Marrow Aspiration

Bone marrow aspiration (BMA) is increasingly being used to harvest stem cells for use in regenerative medicine. The focus of BMA in interventional orthopedics is to maximize the yield of mesenchymal stem cells. The authors present an improved method for BMA that involves fluoroscope or ultrasound guidance combined with anesthesia; in the authors' experience, it produces the highest possible stem cell yield and is well tolerated by patients. The authors provide a step-by-step guide to the process, along with a discussion of technical and other considerations and quick reference guides for ultrasound- and fluoroscope-guided BMA.

Stem Cell Considerations for the Clinician

"Although there is ample evidence that beneficial results can be obtained from the use of mesenchymal stem cells, several questions regarding their use remain to be answered. For many of these questions, preclinical models will be helpful, but the task of evaluating and implementing these findings for orthopaedic patients falls onto the shoulders of clinical researchers. Evaluation of these questions is a daunting, but such a challenge fits the concept of personalized medicine in today's medicine."

Isolating Pediatric Mesenchymal Stem Cells with Enhanced Expansion and Differentiation Capabilities

Mesenchymal stem cells/marrow stromal cells (MSCs) are attractive for applications ranging from research and development to use in clinical therapeutics. However, the most commonly studied MSCs, adult bone marrow MSCs (A-MSCs), are limited by significant donor variation resulting in inconsistent expansion rates and multilineage differentiation capabilities. We have recently obtained permission to isolate pediatric MSCs (P-MSCs) from surplus iliac crest bone chips. Here, we developed a simple and easily replicable isolation protocol yielding P-MSCs, which adhere to MSC defining guidelines. After confirming immunophenotypic marker expression, we compared expansion rates, senescence, morphology, and trilineage differentiation of P-MSCs to A-MSCs for multiple donors. We found P-MSCs have faster in vitro replication, consistently show significantly lower senescence, and are capable of more reproducible multilineage differentiation than A-MSCs. We, therefore, believe P-MSCs are a promising candidate for use in research applications and potentially as part of an allogeneic therapeutic treatment.

The influence of age and osteoporosis on bone marrow stem cells from rats

Objectives

This study aimed to assess the effect of age and osteoporosis on the proliferative and differentiating capacity of bone-marrow-derived mesenchymal stem cells (MSCs) in female rats. We also discuss the role of these factors on expression and migration of cells along the C-X-C chemokine receptor type 4 (CXCR-4) / stromal derived factor 1 (SDF-1) axis.

Methods

Mesenchymal stem cells were harvested from the femora of young, adult, and osteopenic Wistar rats. Cluster of differentiation (CD) marker and CXCR-4 expression was measured using flow cytometry. Cellular proliferation was measured using Alamar Blue, osteogenic differentiation was measured using alkaline phosphatase expression and alizarin red production, and adipogenic differentiation was measured using Oil red O. Cells were incubated in Boyden chambers to quantify their migration towards SDF-1. Data was analyzed using a Student’s t-test, where p-values < 0.05 were considered significant.

Results

CD marker expression and proliferation of the MSCs from the three groups was not significantly different. The young MSCs demonstrated significantly increased differentiation into bone and fat and superior migration towards SDF-1. The migration of SDF-1 doubled with young rats compared with the adult rats (p = 0.023) and it was four times higher when compared with cells isolated from ovariectomized (OVX) osteopenic rats (p = 0.013).

Conclusion

Young rat MSCs are significantly more responsive to osteogenic differentiation, and, contrary to other studies, also demonstrated increased adipogenic differentiation compared with cells from adult and ostopenic rats. Young-rat-derived cells also showed superior migration towards SDF-1 compared with MSCs from OVX and adult control rats.

Cite this article: A. Sanghani-Kerai, L. Osagie-Clouard, G. Blunn, M. Coathup. The influence of age and osteoporosis on bone marrow stem cells from rats. Bone Joint Res 2018;7:289–297. DOI: 10.1302/2046-3758.74.BJR-2017-0302.R1.

Low power laser irradiation and human adipose-derived stem cell treatments promote bone regeneration in critical-sized calvarial defects in rats

Both stem cell therapy and physical treatments have been shown to be beneficial in accelerating bone healing. However, the efficacy of combined treatment with stem cells and physical stimuli for large bone defects remains uncertain. The aim of this study was to evaluate the bone regeneration effects of low-power laser irradiation (LPLI) and human adipose-derived stem cell (ADSC) treatments during fracture repair using a comparative rat calvarial defect model. We evaluated the viability of human ADSCs, which were cultured on a porous PLGA scaffold using an MTS assay. The critical-sized calvarial bone defect rats were divided into 4 groups: control group, LPLI group, ADSC group, and ADSC+LPLI group. Bone formation was evaluated using micro-CT. New bone formation areas and osteogenic factor expression levels were then examined by histomorphological analysis and immunohistochemical staining. Our data showed that PLGA had no cytotoxic effect on human ADSCs. Micro-CT analyses revealed that both the LPLI and ADSC groups showed improved calvarial bone defect healing compared to the control group. In addition, the ADSC+LPLI group showed significantly increased bone volume at 16 weeks after surgery. The area of new bone formation ranked as follows: control group < LPLI group < ADSC group < ADSC+LPLI group. There were significant differences between the groups. In addition, both ADSC and ADSC+LPLI groups showed strong signals of vWF expression. ADSC and LPLI treatments improved fracture repair in critical-sized calvarial defects in rats. Importantly, the combined treatment of ADSCs and LPLI further enhances the bone healing process.

Adipose mesenchymal stem cells from osteoporotic donors preserve functionality and modulate systemic inflammatory microenvironment in osteoporotic cytotherapy

Maintenance of bone homeostasis against diseased microenvironments remains as a major challenge. Recently, mesenchymal stem cells (MSCs) have been unravelled as potent microenvironmental modulators, the systemic infusion of which in cytotherapy can prevent or rescue extensive bone loss via anti-inflammation. However, MSCs also accept microenvironmental regulations; particularly, MSCs from bone marrow (BMMSCs) are prone to pathological microenvironmental factors of bone. In this study, we discovered that BMMSCs from osteoporotic donors of ovariectomized (OVX) mice lost their anti-inflammatory capability and failed to prevent bone loss when infused back into OVX recipients. Nevertheless, MSCs from adipose tissues (ADMSCs) preserved their anti-inflammatory capacity, despite diseased microenvironments of OVX donors, and continued to show protective effects on bone in OVX recipients. In the cellular level, the anti-inflammatory superiority of osteoporotic donor-derived ADMSCs over BMMSCs existed in their distinctive capability to induce T-cell apoptosis, which was molecularly attributed to retained expression levels of critical immunomodulatory genes. Furthermore, these functional discrepancies of BMMSCs and ADMSCs were due to differential stemness, energy metabolism and anti-oxidative defence system, underlying general disparity in their cellular states. Collectively, our findings optimize osteoporotic cytotherapy by using ADMSCs in resistance to and in modulation of diseased microenvironments.

Microenvironmental cues enhance mesenchymal stem cell-mediated immunomodulation and regulatory T-cell expansion

Mesenchymal stem cells (MSCs) are known to both have powerful immunosuppressive properties and promote allograft tolerance. Determining the environmental oxygen tension and inflammatory conditions under which MSCs are optimally primed for this immunosuppressive function is essential to their utilization in promoting graft tolerance. Of particular interest is the mechanisms governing the interaction between MSCs and regulatory T cells (Tregs), which is relatively unknown. We performed our experiments utilizing rat bone marrow derived MSCs. We observed that priming MSCs in hypoxia promotes maintenance of stem-like characteristics, with greater expression of typical MSC cell-surface markers, increased proliferation, and maintenance of differentiation potential. Addition of autologous MSCs to CD4+/allogeneic endothelial cell (EC) co-culture increases regulatory T cell (Treg) proliferation, which is further enhanced when MSCs are primed in hypoxia. Furthermore, MSC-mediated Treg expansion does not require direct cell-cell contact. The expression of indolamine 2,3-dioxygenase, a mediator of MSC immunomodulation, increases when MSCs are primed in hypoxia, and inhibition of IDO significantly decreases the expansion of Tregs. Priming with inflammatory cytokines IFNγ and TNFα increases also expression of markers associated with MSC immunomodulatory function, but decreases MSC proliferation. The expression of IDO also increases when MSCs are primed with inflammatory cytokines. However, there is no increase in Treg expansion when MSCs are primed with IFNγ, suggesting an alternate mechanism for inflammatory-stimulated MSC immunomodulation. Overall, these results suggest that MSCs primed in hypoxia or inflammatory conditions are optimally primed for immunosuppressive function. These results provide a clearer picture of how to enhance MSC immunomodulation for clinical use.

Stem Cells for Cartilage Repair: Preclinical Studies and Insights in Translational Animal Models and Outcome Measures

Due to the restricted intrinsic capacity of resident chondrocytes to regenerate the lost cartilage postinjury, stem cell-based therapies have been proposed as a novel therapeutic approach for cartilage repair. Moreover, stem cell-based therapies using mesenchymal stem cells (MSCs) or induced pluripotent stem cells (iPSCs) have been used successfully in preclinical and clinical settings. Despite these promising reports, the exact mechanisms underlying stem cell-mediated cartilage repair remain uncertain. Stem cells can contribute to cartilage repair via chondrogenic differentiation, via immunomodulation, or by the production of paracrine factors and extracellular vesicles. But before novel cell-based therapies for cartilage repair can be introduced into the clinic, rigorous testing in preclinical animal models is required. Preclinical models used in regenerative cartilage studies include murine, lapine, caprine, ovine, porcine, canine, and equine models, each associated with its specific advantages and limitations. This review presents a summary of recent in vitro data and from in vivo preclinical studies justifying the use of MSCs and iPSCs in cartilage tissue engineering. Moreover, the advantages and disadvantages of utilizing small and large animals will be discussed, while also describing suitable outcome measures for evaluating cartilage repair.

Stem cell therapies for chronic obstructive pulmonary disease: current status of pre-clinical studies and clinical trials

Chronic obstructive pulmonary disease (COPD) is a respiratory disease that has a major impact worldwide. The currently-available drugs mainly focus on relieving the symptoms of COPD patients. Novel regenerative therapeutic approaches have been investigated with the aim of repairing or replacing the injured functional structures of the respiratory system. We summarized the progress made by regenerative therapies for COPD by analyzing results from both pre-clinical studies and completed clinical trials. These approaches include the application of exogenous stem cells or small molecules to stimulate the regeneration by endogenous lung stem/progenitor cells. Exogenous mesenchymal stem cells (MSCs) have been reported to repair the structure and improve the function of the injured respiratory system in COPD models. However, the studies that used MSCs in patients with moderate-to-severe COPD patients did not lead to clear respiratory functional improvements. Exogenous human lung stem cells applied to cryo-injured (CI) lungs of mice have been shown to organize into human-like pulmonary structures, indicating a new property of stem cells that is potentially capable of curing COPD patients. Small molecules like retinoic acid has been shown to lead to regeneration and repair of the damaged lung structures in COPD mouse models probably by activation of endogenous lung stem/progenitor cells. However, retinoic acid or agonists of retinoic acid receptor administered to moderate or severe COPD patients did not improve the density and function of the damaged lung. These novel regenerative approaches have failed in preliminary clinical trials, possibly due to the advanced severity of the disease. Further work should be done to develop the current regenerative approaches for curing patients at different stages of COPD. We suggest that some modifications of the approach in the clinical studies may lead to more successful outcomes of regenerative therapy for COPD.

Differences in the neovascular potential of thymus versus subcutaneous adipose-derived stem cells from patients with myocardial ischaemia

Adipose tissue-derived multipotent mesenchymal cells (ASCs) participate in the information of blood vessels under hypoxic conditions. It is probable that the susceptibility of ASCs to the influence of age and ageing-associated pathologies compromises their therapeutic effectiveness depending on the adipose tissue depot. Our aim was to examine the neovascular potential under hypoxic conditions of ASCs-derived from thymic (thymASCs) and subcutaneous (subASCs) adipose tissue from 39 subjects with and without type 2 diabetes mellitus (T2DM) and of different ages who were undergoing coronary bypass surgery. We confirmed a significant decrease in the percentage of CD34⁺ CD31^- CD45^- subASCs in the cell yield of subASCs and in the survival of cultured endothelial cells in the medium conditioned by the hypox-subASCs with increasing patient age, which was not observed in thymASCs. Whereas the length of the tubules generated by hypox-subASCs tended to correlate negatively with patient age, tubule formation capacity of the hypoxic thymASCs increased significantly. Compared with subASCs, thymASCs from subjects over age 65 and without T2DM showed higher cell yield, tubule formation capacity, vascular endothelial growth factor secretion levels, and ability to promote endothelial cell survival in their conditioned medium. Deterioration in subASCs neovascular potential relative to thymASCs derived from these subjects was accompanied by higher expression levels of NOX4 mRNA and fibrotic proteins. Our results indicate that thymASCs from patients over age 65 and without T2DM have a higher angiogenic potential than those from the other patient groups, suggesting they may be a good candidate for angiogenic therapy in subjects undergoing coronary bypass surgery.

Complete Assessment of Multilineage Differentiation Potential of Human Skeletal Muscle-Derived Mesenchymal Stem/Stromal Cells

The minimal criteria for mesenchymal stem/stromal cell (MSC) identification set by the International Society for Cellular Therapy include plastic adherence, presence and absence of a set of surface antigens and in vitro multilineage differentiation. This differentiation is assessed through stimulation of MSCs with defined combination and concentration of growth factors towards specific lineages and histological confirmation of the presence of differentiated cells. Here we provide protocols for multilineage differentiation, namely, osteogenesis, adipogenesis, chondrogenesis and myogenesis. We also provide their respective histological analyses.

Effect of Tumor Necrosis Factor Alpha Dose and Exposure Time on Tumor Necrosis Factor-Induced Gene-6 Activation by Neonatal and Adult Mesenchymal Stromal Cells

Tumor necrosis factor alpha (TNF-α) induced protein 6 is a major anti-inflammatory mediator released by activated mesenchymal stromal cells (MSCs). Neonatal MSCs are considered more metabolically active than cells derived from adult tissues, and potentially less heterogeneous. We hypothesized that a TNF-α-activated neonatal MSC population [human umbilical cord perivascular cells (HUCPVCs)] would show an enhanced level of TSG-6 activation compared with adult bone marrow MSCs (BMMSCs). Thus, we stimulated HUCPVCs, and both human BMMSCs (hBMMSCs) and mouse BMMSCs (mBMMSCs) with 1, 10, 50, and 100 ng/mL of recombinant TNF-α over various exposure times. Supernatant, and total RNA, of the cells were collected for measurement of both TSG-6 RNA expression, and secreted TSG-6 protein. To compare gene levels, quantification was done by normalizing the expression levels of TSG-6 to the geometric mean of the three most stable reference genes, out of a cohort of 30 tested genes, using the Pfaffl method. We found that HUCPVCs exhibited both an enhanced and more rapid response to low dose (1 ng/mL) TNF-α exposure resulting in ∼11.5-fold increase in TSG-6 expression within the first 30 min. In contrast, hBMMSCs showed 2-fold increase by 1 h that increased to 9.5-fold with a higher (50 ng/mL) TNF-α exposure for the same time. mBMMSCs showed a two-fold increase after 24 h that was independent of TNF-α concentration. Thus, although TSG-6 expression level varied among donors, both hMSC populations exhibited enhanced TSG-6 upregulation, upon TNF-α stimulation, compared with mBMMSCs. In conclusion, HUCPVCs showed higher sensitivity, and a prompter response to TNF-α stimulation compared with hBMMSCs. Thus, neonatal MSCs may be a stronger candidate population than those derived from adult bone marrow to treat inflammatory diseases.

Methods and practices to diversify cell-based products

Medicinal signaling cell (MSC)-based products represent emerging treatments in various therapeutic areas including cardiometabolic, inflammation, autoimmunity, orthopedics, wound healing and oncology. Exploring innovation beyond minimally manipulated plastic-adherent ex vivo expanded allogeneic MSCs enables product delineation. Product delineation is on the critical path to maximize clinical benefits and market access. An innovation framework is presented here along various innovation dimensions comprising composition-of-matter by means of positive cell surface markers, formulation varying for example the cell dose or the preservation mode and medium, manufacturing to adapt the secretome of MSCs to the condition of interest, the mode of delivery and corresponding delivery devices, as well as molecular engineering and biomarkers. The rationale of the innovation space thus described applies generally to all cell-based therapies.

Function of microRNAs in the Osteogenic Differentiation and Therapeutic Application of Adipose-Derived Stem Cells (ASCs)

Traumatic wounds with segmental bone defects represent substantial reconstructive challenges. Autologous bone grafting is considered the gold standard for surgical treatment in many cases, but donor site morbidity and associated post-operative complications remain a concern. Advances in regenerative techniques utilizing mesenchymal stem cell populations from bone and adipose tissue have opened the door to improving bone repair in the limbs, spine, and craniofacial skeleton. The widespread availability, ease of extraction, and lack of immunogenicity have made adipose-derived stem cells (ASCs) particularly attractive as a stem cell source for regenerative strategies. Recently it has been shown that small, non-coding miRNAs are involved in the osteogenic differentiation of ASCs. Specifically, microRNAs such as miR-17, miR-23a, and miR-31 are expressed during the osteogenic differentiation of ASCs, and appear to play a role in inhibiting various steps in bone morphogenetic protein-2 (BMP2) mediated osteogenesis. Importantly, a number of microRNAs including miR-17 and miR-31 that act to attenuate the osteogenic differentiation of ASCs are themselves stimulated by transforming growth factor β-1 (TGFβ-1). In addition, transforming growth factor β-1 is also known to suppress the expression of microRNAs involved in myogenic differentiation. These data suggest that preconditioning strategies to reduce TGFβ-1 activity in ASCs may improve the therapeutic potential of ASCs for musculoskeletal application. Moreover, these findings support the isolation of ASCs from subcutaneous fat depots that tend to have low endogenous levels of TGFβ-1 expression.

Zinc sulfate contributes to promote telomere length extension via increasing telomerase gene expression, telomerase activity and change in the TERT gene promoter CpG island methylation status of human adipose-derived mesenchymal stem cells

The use of mesenchymal stem cells (MSCs) for cell therapy and regenerative medicine has received widespread attention over the past few years, but their application can be complicated by factors such as reduction in proliferation potential, the senescent tendency of the MSCs upon expansion and their age-dependent decline in number and function. It was shown that all the mentioned features were accompanied by a reduction in telomerase activity and telomere shortening. Furthermore, the role of epigenetic changes in aging, especially changes in promoter methylation, was reported. In this study, MSCs were isolated from the adipose tissue with enzymatic digestion. In addition, immunocytochemistry staining and flow cytometric analysis were performed to investigate the cell-surface markers. In addition, alizarin red-S, sudan III, toluidine blue, and cresyl violet staining were performed to evaluate the multi-lineage differentiation of hADSCs. In order to improve the effective application of MSCs, these cells were treated with 1.5 × 10-8 and 2.99 × 10-10 M of ZnSO4 for 48 hours. The length of the absolute telomere, human telomerase reverse transcriptase (hTERT) gene expression, telomerase activity, the investigation of methylation status of the hTERT gene promoter and the percentage of senescent cells were analyzed with quantitative real-time PCR, PCR-ELISA TRAP assay, methylation specific PCR (MSP), and beta-galactosidase (SA-β-gal) staining, respectively. The results showed that the telomere length, the hTERT gene expression, and the telomerase activity had significantly increased. In addition, the percentage of senescent cells had significantly decreased and changes in the methylation status of the CpG islands in the hTERT promoter region under treatment with ZnSO4 were seen. In conclusion, it seems that ZnSO4 as a proper antioxidant could improve the aging-related features due to lengthening of the telomeres, increasing the telomerase gene expression, telomerase activity, decreasing aging, and changing the methylation status of hTERT promoter; it could potentially beneficial for enhancing the application of aged-MSCs.

[Research progress of the donor factors and experimental factors affecting adipogenic differentiation of adipose derived stem cells]

Objective

To summarize the donor factors and experimental factors that affect adipogenic differentiation of adipose derived stem cells, so as to provide reference for adipogenic differentiation of adipose derived stem cells.

Methods

The related research literature about donor factors and experimental factors affecting adipogenic differentiation of adipose derived stem cells in recent years was extensively reviewed and summarized.

Results

There are a lot of donor factors and experimental factors affecting adipogenic differentiation of adipose derived stem cells, but some of the factors are still controversial, such as donor age, health status, adipose tissue of different parts, and so on. These factors need to be further studied.

Conclusion

The donor factors and experimental factors that affect adipogenic differentiation of adipose derived stem cells should be deeply studied and the controversial issues should be clarified to lay a solid foundation for the application of adipose derived stem cells in adipose tissue engineering.

Skeletal Muscle Regenerative Potential of Human MuStem Cells following Transplantation into Injured Mice Muscle

After intra-arterial delivery in the dystrophic dog, allogeneic muscle-derived stem cells, termed MuStem cells, contribute to long-term stabilization of the clinical status and preservation of the muscle regenerative process. However, it remains unknown whether the human counterpart could be identified, considering recent demonstrations of divergent features between species for several somatic stem cells. Here, we report that MuStem cells reside in human skeletal muscle and display a long-term ability to proliferate, allowing generation of a clinically relevant amount of cells. Cultured human MuStem (hMuStem) cells do not express hematopoietic, endothelial, or myo-endothelial cell markers and reproducibly correspond to a population of early myogenic-committed progenitors with a perivascular/mesenchymal phenotypic signature, revealing a blood vessel wall origin. Importantly, they exhibit both myogenesis in vitro and skeletal muscle regeneration after intramuscular delivery into immunodeficient host mice. Together, our findings provide new insights supporting the notion that hMuStem cells could represent an interesting therapeutic candidate for dystrophic patients.

Meta-analysis on the treatment of diabetic foot ulcers with autologous stem cells

Over the last decade, many studies have indicated a therapeutic potential for treating diabetic lower extremity ulcers with autologous stem cells. The aim of the current study was to conduct a systematic review and meta-analysis of the treatment of diabetic foot ulcers (DFUs) with autologous stem cells. The search strategy included the Pubmed, EMBASE, Web of Science, and Cochrane’s Library databases. The endpoint measured was the healing of DFUs.

Six eligible randomized controlled trial (RCT) studies were screened from related published studies and reviewed for meta-analysis. The overall meta-analysis showed that stem cell administration was significantly favorable for healing diabetic ulcers (mean difference (MD) 0.52, 95% confidence interval (CI) 0.38–0.65; p < 0.00001). Subgroup analyses indicated that stem cells seemed to exert similar beneficial effects on patients with ulcer size ≥ 5 cm² (MD 0.76, 95% CI 0.55–0.97; p < 0.00001) and < 5 cm² (MD 0.43, 95% CI 0.31–0.54; p < 0.00001). Furthermore, stem cells had similar effects on patients aged ≥ 70 years (MD 0.61, 95% CI 0.14–1.08; p = 0.01) and < 70 years (MD 0.47, 95% CI 0.35–0.58; p < 0.00001). This systematic review and meta-analysis suggests a promising role for stem cells in DFU treatment. This review will pave the way to further study on the long-term effects of stem cell-based therapy and large-scale RCTs.

Efficacy and Persistence of Allogeneic Adipose-Derived Mesenchymal Stem Cells Combined with Hyaluronic Acid in Osteoarthritis After Intra-articular Injection in a Sheep Model

Although a number of studies have reported efficacy of autologous adipose-derived mesenchymal stem cells (AD-MSCs) in treating osteoarthritis (OA) no reliable evidences demonstrate whether allogeneic AD-MSCs can efficiently block OA progression in a large animal model. This study explored the efficacy and survival of allogeneic AD-MSCs combined with hyaluronic acid (HA) after intra-articular (IA) injection in a sheep OA model, which were conventionally established by anterior cruciate ligament resection and medial meniscectomy. Allogeneic AD-MSCs from donor sheep at high (5 × 10⁷ cells) and low (1 × 10⁷ cells) doses combined with HA, HA alone, or saline alone were injected into the OA sheep at 3 and 6 weeks after surgery, respectively. Evaluations by magnetic resonance imaging (MRI), macroscopy, micro-computed tomography, and cartilage-specific staining demonstrated that AD-MSCs+HA treated groups preserved typical articular cartilage feature. Inflammatory factors from synovial fluid of AD-MSCs+HA treated groups were significantly lower than those in the HA alone group. Notably, transforming growth factor beta 1 and insulin-like growth factor 1 were detected in the supernatant of cultured AD-MSCs. In addition, labeling signals of allogeneic AD-MSCs could be detected by MRI after 14 weeks of injection and be found in synovium by histology. These results indicated that IA injection of allogeneic AD-MSCs combined with HA could efficiently block OA progression and promote cartilage regeneration and allogeneic AD-MSCs might survive at least 14 weeks after IA injection.

Mammalian MSC from selected species: Features and applications

Mesenchymal stromal/stem cells (MSC) are promising candidates for cellular therapy of different diseases in humans and in animals. Following the guidelines of the International Society for Cell Therapy, human MSC may be identified by expression of a specific panel of cell surface markers (CD105+, CD73+, CD90+, CD34-, CD14-, or CD11b-, CD79- or CD19-, HLA-DR-). In addition, multiple differentiation potential into at least the osteogenic, adipogenic, and chondrogenic lineage is a main criterion for MSC definition. Human MSC and MSC of a variety of mammals isolated from different tissues meet these criteria. In addition to the abovementioned, they express many more cell surface markers. Yet, these are not uniquely expressed by MSC. The gross phenotypic appearance like marker expression and differentiation potential is similar albeit not identical for MSC from different tissues and species. Similarly, MSC may feature different biological characteristics depending on the tissue source and the isolation and culture procedures. Their versatile biological qualities comprising immunomodulatory, anti-inflammatory, and proregenerative capacities rely largely on the migratory and secretory capabilities of MSC. They are attracted to sites of tissue lesion and secrete factors to promote self-repair of the injured tissue. This is a big perspective for clinical MSC applications in both veterinary and human medicine. Phase I/II clinical trials have been initiated to assess safety and feasibility of MSC therapies in acute and chronic disease settings. Yet, since the mode of MSC action in a specific disease environment is still unknown at large, it is mandatory to unravel the response of MSC from a given source onto a specific disease environment in suitable animal models prior to clinical applications. © 2017 International Society for Advancement of Cytometry.

Cranial reconstruction using allogeneic mesenchymal stromal cells: A phase 1 first-in-human trial

Cranioplasty is necessary for patients that have undergone craniectomy following trauma, stroke or other causes of elevated intracranial pressure. This study assessed the effectiveness of treating cranial defects with allogeneic mesenchymal stromal cells (MSC) on a ceramic carrier and polymer scaffold, to produce viable bone and healing of a cranial void. Patients underwent a baseline computed tomography (CT) scan for construct design. Two sets of interlocking moulds were three-dimensional printed to enable shaping of two polymer meshes, which formed the boundaries of the construct corresponding to restoration of the skull interna and externa. In vitro expanded donor MSC were seeded onto ceramic granules in a good manufacturing practices facility. The inner mesh was placed in theatre, followed by the cell-loaded granules, and the outer mesh. Patients were followed-up at 3, 6 and 12 months and cosmesis assessed visually, while bone formation was assessed by CT scans at 1 day, 3 months and 12 months. Manufacture of the construct and surgery was uneventful for all three patients. Initial cosmesis was excellent with no complications. New bone formation was demonstrated by analysis of CT data; however, bone resorption was noted in all 3 cases on the 12-month CT scan. The lack of rigidity of the construct in an environment with continuous pulsatile movement may be preventing the formation of solid bone. It is possible to produce a customized allogeneic MSC construct for cranial reconstruction to replace cranial bone with good cosmesis, using a combination of medical computer modelling, rapid-prototyping and tissue engineering.

Identification and characterization of a rich population of CD34+ mesenchymal stem/stromal cells in human parotid, sublingual and submandibular glands

Mesenchymal stem/stromal cells (MSCs) play crucial roles in maintaining tissue homeostasis during physiological turnovers and injuries. Very little is known about the phenotype, distribution and molecular nature of MSCs in freshly isolated human salivary glands (SGs) as most reports have focused on the analysis of cultured MSCs. Our results demonstrate that the cell adhesion molecule CD34 was widely expressed by the MSCs of human major SGs, namely parotid (PAG), sublingual (SLG) and submandibular (SMG) glands. Further, gene expression analysis of CD34⁺ cells derived from fetal SMGs showed significant upregulation of genes involved in cellular adhesion, proliferation, branching, extracellular matrix remodeling and organ development. Moreover, CD34⁺ SMG cells exhibited elevated expression of genes encoding extracellular matrix, basement membrane proteins, and members of ERK, FGF and PDGF signaling pathways, which play key roles in glandular development, branching and homeostasis. In vitro CD34⁺ cell derived SG-MSCs revealed multilineage differentiation potential. Intraglandular transplantation of cultured MSCs in immunodeficient mice led to their engraftment in the injected and uninjected contralateral and ipsilateral glands. Engrafted cells could be localized to the stroma surrounding acini and ducts. In summary, our data show that CD34⁺ derived SG-MSCs could be a promising cell source for adoptive cell-based SG therapies, and bioengineering of artificial SGs.

Age, gender, and percentage of circulating osteoprogenitor (COP) cells: The COP Study

Circulating osteoprogenitor (COP) cells are blood-borne cells which express a variety of osteoblastic markers and are able to form bone nodules in vivo. Whereas a high percentage of COP cells (%COP) is associated with vascular calcification, low %COP has been associated with disability and frailty. However, the reference range of %COP in age- and gender-matching populations, and the age-related changes in %COP remain unknown. A cross-sectional study was undertaken in 144 healthy volunteers in Western Sydney (20-90year-old, 10 male and 10 female subjects per decade). %COP was quantified by flow cytometry. A high inter-and intra-rater reliability was found. In average, in this healthy population average of %COP was 0.42. There was no significant difference in %COP among the age groups. Similarly, no significant difference was found in %COP with gender, weight, height or BMI. In addition, we identified a normal reference range of %COP of 0.1-3.8%. In conclusion, in addition to the identification of steady levels of COP cells with age, we also identified a normal reference range of %COP, which could be used in future studies looking at musculoskeletal diseases in older populations.

Muscle-derived stem cells in peripheral nerve regeneration: reality or illusion?

Owing to the complicated and time-consuming regenerative process, the repair of injured peripheral nerves depends largely on ongoing stem-cell therapy. Decades ago, researchers successfully isolated and identified muscle-derived stem cells (MDSCs) and discovered their potential for multidifferentiation. MDSCs play an important role in trauma repair associated with neuromuscular and vascular injury by simultaneously promoting tissue regrowth via direct differentiation and systematic secretion under physiological conditions. However, the isolation, culture, induction and application of MDSCs require further methodological analysis before clinical application. In this review, we comprehensively discuss the challenges associated with neural regeneration and reviewed the progress of stem cell based regenerative medicine, in an effort to realize the potential of MDSCs in nerve regeneration.

Purified Adipose-Derived Stromal Cells Provide Superior Fat Graft Retention Compared with Unenriched Stromal Vascular Fraction

Cell-assisted lipotransfer has shown much promise as a technique to improve fat graft retention in both mouse and human studies. However, the literature varies as to whether fresh stromal vascular fraction or culture-expanded adipose-derived stromal cells are used to augment volume retention. The authors' study sought to determine whether there was a significant advantage to using adipose-derived stromal cells over unpurified stromal vascular fraction cells in a mouse model of cell-assisted lipotransfer.

Reduced cellularity of bone marrow in multiple sclerosis with decreased MSC expansion potential and premature ageing in vitro

Background:

Autologous bone-marrow-derived cells are currently employed in clinical studies of cell-based therapy in multiple sclerosis (MS) although the bone marrow microenvironment and marrow-derived cells isolated from patients with MS have not been extensively characterised.

Objectives:

To examine the bone marrow microenvironment and assess the proliferative potential of multipotent mesenchymal stromal cells (MSCs) in progressive MS.

Methods:

Comparative phenotypic analysis of bone marrow and marrow-derived MSCs isolated from patients with progressive MS and control subjects was undertaken.

Results:

In MS marrow, there was an interstitial infiltrate of inflammatory cells with lymphoid (predominantly T-cell) nodules although total cellularity was reduced. Controlling for age, MSCs isolated from patients with MS had reduced in vitro expansion potential as determined by population doubling time, colony-forming unit assay, and expression of β-galactosidase. MS MSCs expressed reduced levels of Stro-1 and displayed accelerated shortening of telomere terminal restriction fragments (TRF) in vitro.

Conclusion:

Our results are consistent with reduced proliferative capacity and ex vivo premature ageing of bone-marrow-derived cells, particularly MSCs, in MS. They have significant implication for MSC-based therapies for MS and suggest that accelerated cellular ageing and senescence may contribute to the pathophysiology of progressive MS.

Potential clinical applications of placental stem cells for use in fetal therapy of birth defects

Placental stem cells are of growing interest for a variety of clinical applications due to their multipotency and ready availability from otherwise frequently discarded biomaterial. Stem cells derived from the placenta have been investigated in a number of disease processes, including wound healing, ischemic heart disease, autoimmune disorders, and chronic lung or liver injury. Fetal intervention for structural congenital defects, such as spina bifida, has rapidly progressed as a field due to advances in maternal-fetal medicine and improving surgical techniques. In utero treatment of structural, as well as non-structural, congenital disorders with cell-based therapies is of particular interest given the immunologic immaturity and immunotolerant environment of the developing fetus. A comprehensive literature review was performed to assess the potential utilization of placenta-derived stem cells for in utero treatment of congenital disorders. Most studies are still in the preclinical phase, utilizing animal models of common congenital disorders. Future research endeavors may include autologous transplantation, gene transfers, induced pluripotent stem cells, or cell-free therapies derived from the stem cell secretome. Though much work still needs to be done, placental stem cells are a promising therapeutic agent for fetal intervention for congenital disease.

Inflammation, ageing, and bone regeneration

Bone healing involves complex biological pathways and interactions among various cell types and microenvironments. Among them, the monocyte–macrophage–osteoclast lineage and the mesenchymal stem cell–osteoblast lineage are critical, in addition to an initial inflammatory microenvironment. These cellular interactions induce the necessary inflammatory milieu and provide the cells for bone regeneration and immune modulation. Increasing age is accompanied with a rise in the basal state of inflammation, potentially impairing osteogenesis.

The translational potential of this article: Translational research has shown multiple interactions between inflammation, ageing, and bone regeneration. This review presents recent, relevant considerations regarding the effects of inflammation and ageing on bone healing.

MicroRNA-183-5p Increases with Age in Bone-Derived Extracellular Vesicles, Suppresses Bone Marrow Stromal (Stem) Cell Proliferation, and Induces Stem Cell Senescence

Microvesicle- and exosome-mediated transport of microRNAs (miRNAs) represents a novel cellular and molecular pathway for cell-cell communication. In this study, we tested the hypothesis that these extracellular vesicles (EVs) and their miRNAs might change with age, contributing to age-related stem cell dysfunction. EVs were isolated from the bone marrow interstitial fluid (supernatant) of young (3-4 months) and aged (24-28 months) mice to determine whether the size, concentration, and miRNA profile of EVs were altered with age in vivo. Results show that EVs isolated from bone marrow are CD63 and CD9 positive, and the concentration and size distribution of bone marrow EVs are similar between the young and aged mice. Bioanalyzer data indicate that EVs from both young and aged mice are highly enriched in miRNAs, and the miRNA profile of bone marrow EVs differs significantly between the young and aged mice. Specifically, the miR-183 cluster (miR-96/-182/-183) is highly expressed in aged EVs. In vitro assays demonstrate that aged EVs are endocytosed by primary bone marrow stromal cells (BMSCs), and these aged EVs inhibit the osteogenic differentiation of young BMSCs. Transfection of BMSCs with miR-183-5p mimic reduces cell proliferation and osteogenic differentiation, increases senescence, and decreases protein levels of the miR-183-5p target heme oxygenase-1 (Hmox1). In vitro assays utilizing H₂O₂-induced oxidative stress show that H₂O₂ treatment of BMSCs increases the abundance of miR-183-5p in BMSC-derived EVs, and Amplex Red assays demonstrate that H₂O₂ is elevated in the bone marrow microenvironment with age. Together, these data indicate that aging and oxidative stress can significantly alter the miRNA cargo of EVs in the bone marrow microenvironment, which may in turn play a role in stem cell senescence and osteogenic differentiation by reducing Hmox1 activity.

Niche matters: The comparison between bone marrow stem cells and endometrial stem cells and stromal fibroblasts reveal distinct migration and cytokine profiles in response to inflammatory stimulus

Objective

Intrinsic inflammatory characteristics play a pivotal role in stem cell recruitment and homing through migration where the subsequent change in niche has been shown to alter these characteristics. The bone marrow mesenchymal stem cells (bmMSCs) have been demonstrated to migrate to the endometrium contributing to the stem cell reservoir and regeneration of endometrial tissue. Thus, the aim of the present study was to compare the inflammation-driven migration and cytokine secretion profile of human bmMSCs to endometrial mesenchymal stem cells (eMSCs) and endometrial fibroblasts (eSFs).

Materials and methods

The bmMSCs were isolated from bone marrow aspirates through culturing, whereas eMSCs and eSFs were FACS-isolated. All cell types were tested for their surface marker, proliferation profiles and migration properties towards serum and inflammatory attractants. The cytokine/chemokine secretion profile of 35 targets was analysed in each cell type at basal level along with lipopolysaccharide (LPS)-induced state.

Results

Both stem cell types, bmMSCs and eMSCs, presented with similar stem cell surface marker profiles as well as possessed high proliferation and migration potential compared to eSFs. In multiplex assays, the secretion of 16 cytokine targets was detected and LPS stimulation expanded the cytokine secretion pattern by triggering the secretion of several targets. The bmMSCs exhibited higher cytokine secretion of vascular endothelial growth factor (VEGF)-A, stromal cell-derived factor-1 alpha (SDF)-1α, interleukin-1 receptor antagonist (IL-1RA), IL-6, interferon-gamma inducible protein (IP)-10, monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)1α and RANTES compared to eMSCs and/or eSFs after stimulation with LPS. The basal IL-8 secretion was higher in both endometrial cell types compared to bmMSCs.

Conclusion

Our results highlight that similar to bmMSCs, the eMSCs possess high migration activity while the differentiation process towards stromal fibroblasts seemed to result in loss of stem cell surface markers, minimal migration activity and a subtler cytokine profile likely contributing to normal endometrial function.

Ligament-Derived Stem Cells: Identification, Characterisation, and Therapeutic Application

Ligament is prone to injury and degeneration and has poor healing potential and, with currently ineffective treatment strategies, stem cell therapies may provide an exciting new treatment option. Ligament-derived stem cell (LDSC) populations have been isolated from a number of different ligament types with the majority of studies focussing on periodontal ligament. To date, only a few studies have investigated LDSC populations in other types of ligament, for example, intra-articular ligaments; however, this now appears to be a developing field. This literature review aims to summarise the current information on nondental LDSCs including in vitro characteristics of LDSCs and their therapeutic potential. The stem cell niche has been shown to be vital for stem cell survival and function in a number of different physiological systems; therefore, the LDSC niche may have an impact on LDSC phenotype. The role of the LDSC niche on LDSC viability and function will be discussed as well as the therapeutic potential of LDSC niche modulation.

Decreased osteogenesis in mesenchymal stem cells derived from the aged mouse is associated with enhanced NF-κB activity

Aging is associated with significant bone loss and delayed fracture healing. NF-κB activation is highly correlated with inflammatory-associated bone diseases including infection, wear particle exposure, and chronic inflammation during natural aging processes. The critical roles of NF-κB in both the pro-inflammatory response and osteoclast-mediated bone resorption have been well defined. However, the biological effects of NF-κB activation in mesenchymal stem cell (MSC)-mediated bone formation remain largely unknown. In the current study, bone marrow-MSCs were isolated from young (8 weeks old) and aged (72 weeks old) mice. NF-κB activity in MSCs at basal levels and under different biological conditions were determined by our recently established lentiviral vector-based luciferase reporter assay. We found that NF-κB activity was increased in aged MSCs at basal levels or when exposed to low dose (10 or 100 ng/ml) lipopolysaccharide (LPS); this effect was not seen when the cells were exposed to higher dose (1 μg/ml) LPS. During osteogenesis, NF-κB activity was increased in aged MSCs at weeks 1 and 2, but showed no significant difference at week 3. Both Smurf2 and TAZ, the NF-κB target genes that regulate osteogenic differentiation, were increased in aged MSCs. In addition, the expression of RANKL was dramatically increased, and OPG was decreased in aged MSCs. Our findings suggest that targeting NF-κB activity in MSCs has the potential to modulate aging-associated bone loss, or enhance bone-healing in aged patients. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:281-288, 2017.

Role of the Cytokine-like Hormone Leptin in Muscle-bone Crosstalk with Aging

The cytokine-like hormone leptin is a classic adipokine that is secreted by adipocytes, increases with weight gain, and decreases with weight loss. Additional studies have, however, shown that leptin is also produced by skeletal muscle, and leptin receptors are abundant in both skeletal muscle and bone-derived mesenchymal (stromal) stem cells. These findings suggest that leptin may play an important role in muscle-bone crosstalk. Leptin treatment in vitro increases the expression of myogenic genes in primary myoblasts, and leptin treatment in vivo increases the expression of microRNAs involved in myogenesis. Bone marrow adipogenesis is associated with low bone mass in humans and rodents, and leptin can reduce marrow adipogenesis centrally through its receptors in the hypothalamus as well as directly via its receptors in bone marrow stem cells. Yet, central leptin resistance can increase with age, and low circulating levels of leptin have been observed among the frail elderly. Thus, aging appears to significantly alter leptin-mediated crosstalk among various organs and tissues. Aging is associated with bone loss and muscle atrophy, contributing to frailty, postural instability, and the incidence of falls. Therapeutic interventions such as protein and amino acid supplementation that can increase muscle mass and muscle-derived leptin may have multiple benefits for the elderly that can potentially reduce the incidence of falls and fractures.

Stem cells in degenerative orthopaedic pathologies: effects of aging on therapeutic potential

PURPOSE

The purpose of this study was to summarize the current evidence on the use of stem cells in the elderly population with degenerative orthopaedic pathologies and to highlight the pathophysiologic mechanisms behind today's therapeutic challenges in stem cell-based regeneration of destructed tissues in the elderly patients with osteoarthritis (OA), degenerative disc disease (DDD), and tendinopathies.

METHODS

Clinical and basic science studies that report the use of stem cells in the elderly patients with OA, DDD, and tendinopathies were identified using a PubMed search. The studies published in English have been assessed, and the best and most recent evidence was included in the current study.

RESULTS

Evidence suggests that, although short-term results regarding the effects of stem cell therapy in degenerative orthopaedic pathologies can be promising, stem cell therapies do not appear to reverse age-related tissue degeneration. Causes of suboptimal outcomes can be attributed to the decrease in the therapeutic potential of aged stem cell populations and the regenerative capacity of these cells, which might be negatively influenced in an aged microenvironment within the degenerated tissues of elderly patients with OA, DDD, and tendinopathies.

CONCLUSIONS

Clinical protocols guiding the use of stem cells in the elderly patient population are still under development, and high-level randomized controlled trials with long-term outcomes are lacking. Understanding the consequences of age-related changes in stem cell function and responsiveness of the in vivo microenvironment to stem cells is critical when designing cell-based therapies for elderly patients with degenerative orthopaedic pathologies.

Knee Cartilage Regeneration with Umbilical Cord Mesenchymal Stem Cells Embedded in Collagen Scaffold Using Dry Arthroscopy Technique

Articular cartilage injuries lead to progressive degeneration of the joint with subsequent progression to osteoarthritis, which currently becomes a serious health and economic issue. Due to limited capability for self-regeneration, cartilage repair remains a challenge for the present-day orthopedics. Currently, available therapeutic methods fail to provide satisfactory results. A search for other strategies that could regenerate a hyaline-like tissue with a durable effect and adequate mechanical properties is underway. Tissue engineering strategies comprise the use of an appropriately chosen scaffold in combination with seeding cells. Mesenchymal stem cells (MSC) provide an interesting new option in regenerative medicine with solid preclinical data and first promising clinical results. They act not only through direct cartilage formation, but also due to paracrine effects, such as releasing trophic factors, anti-inflammatory cytokines, and promoting angiogenesis. The MSC can be applied in an allogeneic setting without eliciting a host immune response. Out of the various available sources, MSC derived from Wharton's jelly of an umbilical cord seem to have many advantages over their counterparts. This article details a novel, single-staged, and minimally invasive technique for cartilage repair that involves dry arthroscopic implantation of scaffold-embedded allogenic mesenchymal stem cells isolated from umbilical cord Wharton's jelly.

The effects of the DNA methyltranfserases inhibitor 5-Azacitidine on ageing, oxidative stress and DNA methylation of adipose derived stem cells

Human adipose tissue is a great source of adult mesenchymal stem cells (MSCs) which are recognized from their ability to self‐renew and differentiation into multiple lineages. MSCs have promised a vast therapeutic potential in treatment many diseases including tissue injury and immune disorders. However, their regenerative potential profoundly depends on patients’ age. Age‐related deterioration of MSC is associated with cellular senescence mainly caused by increased DNA methylation status, accumulation of oxidative stress factors and mitochondria dysfunction. We found that DNA methyltransferase (DNMT) inhibitor i.e. 5‐Azacytidine (5‐AZA) reversed the aged phenotype of MSCs. Proliferation rate of cells cultured with 5‐AZA was increased while the accumulation of oxidative stress factors and DNA methylation status were decreased. Simultaneously the mRNA levels of TET proteins involved in demethylation process were elevated in those cells. Moreover, cells treated with 5‐AZA displayed reduced reactive oxygen species (ROS) accumulation, ameliorated superoxide dismutase activity and increased BCL‐2/BAX ratio in comparison to control group. Our results indicates that, treating MSCs with 5‐AZA can be justified therapeutic intervention, that can slow‐down and even reverse aged‐ related degenerative changes in those cells.

Cellular mechanical properties reflect the differentiation potential of nucleus pulposus-derived progenitor cells

Mechanical properties of cells reflect differences in cellular subpopulations, differentiation potency, and cell behaviors. Previous study has revealed that intervertebral disc (IVD) degeneration leads to alterations in cell behavior and differentiation potency. Human nucleus pulposus-derived progenitor cells (NPPCs) are an attractive cell sources for IVD regeneration. However, the relationship between mechanical properties and differentiation potential in different NPPC subpopulations is few known. In this study, mechanical properties of different NPPC subpopulations were measured via atomic force microscopy (AFM) and correlated with differentiation potential of NPPCs. We found that elastic modulus, relaxed modulus, and instantaneous modulus were positively correlated with osteogenic potential of NPPCs. And apparent viscosity was correlated with chondrogenic potential of NPPCs. These results indicated that the mechanical properties were predictive markers for differentiation potential of NPPC subpopulations, and could be used for enrichment based on differentiation potential, which could significantly improve the outcome of IVD regeneration.