Why are MSCs therapeutic? New data: new insight

Curcumin Improves Human Umbilical Cord-Derived Mesenchymal Stem Cell Survival via ERK1/2 Signaling and Promotes Motor Outcomes After Spinal Cord Injury

Human umbilical cord-derived mesenchymal stem cell (hUC-MSC) transplantation is thought to be a promising strategy for treating spinal cord injury (SCI). However, the low survival rate of transplanted hUC-MSCs limits their clinical application in cell replacement therapy. Curcumin can suppress inflammation after SCI; however, it remains unknown whether curcumin can modulate the survival of transplanted hUC-MSCs. In this study, to investigate whether curcumin could strengthen the therapeutic effects of hUC-MSC transplantation on SCI, we induced hUC-MSC apoptosis with TNF-α, transplanted hUC-MSC into SCI rats, and assessed the antiapoptotic effect and mechanism of curcumin. LDH release analysis and flow cytometry demonstrated that TNF-α led to hUC-MSC apoptosis and that curcumin increased the hUC-MSC survival rate in a dose-dependent manner. In addition, we showed that the phosphorylation levels of ERK1/2, JNK, and P38 were upregulated in apoptotic hUC-MSCs, while curcumin increased the phosphorylation of ERK1/2 but did not activate JNK or P38, and these effects were reversed by the p42/44 antagonist U0126. Furthermore, we found that the motor function scores and number of surviving HNA-positive cells were significantly increased after curcumin and hUC-MSC transplantation therapy 8 weeks post-SCI, while U0126 markedly attenuated these effects. These data confirmed that curcumin suppressed hUC-MSC apoptosis through the ERK1/2 signaling pathway and that combined curcumin and hUC-MSC treatment improved motor function in rats after SCI. The current research provides a strong basis for hUC-MSC replacement therapy in conjunction with curcumin in the treatment and management of SCI in humans.

Replicative Senescence and Expression of Autophagy Genes in Mesenchymal Stromal Cells

Cell senescence leads to a number of changes in the properties of mesenchymal stromal cells (MSCs). In particular, the number of damaged structures is increased producing negative effect on intracellular processes. Elimination of the damaged molecules and organelles occurs via autophagy that can be important in the context of aging. Cultivation under low oxygen level can be used as an approach for enhancement of MSC therapeutic properties and "slowing down" cell senescence. The goal of this work was to study some morphological and functional characteristics and expression of autophagy-associated genes during replicative senescence of MSCs under different oxygen concentration. The study revealed changes in the regulation of autophagy at the transcriptional level. Upregulation of the expression of autophagosome membrane growth genes ATG9A and ULK1, of the autophagosome maturation genes CTSD, CLN3, GAA, and GABARAPL1, of the autophagy regulation genes TP53, TGFB1, BCL2L1, FADD, and HTT was shown. These changes were accompanied by downregulation of IGF1 and TGM2 expression. Increase of the lysosomal compartment volume was observed in the senescent MSCs that also indicated increase of their degradation activity. The number of lysosomes was decreased following prolonged cultivation under low oxygen concentration (5%). The replicative senescence of MSCs under conditions of different oxygen levels led to the similar modifications in the expression of the autophagy-associated genes.

De novo Vessel Formation Through Cross-Talk of Blood-Derived Cells and Mesenchymal Stromal Cells in the Absence of Pre-existing Vascular Structures

BACKGROUND

The generation of functional blood vessels remains a key challenge for regenerative medicine. Optimized in vitro culture set-ups mimicking the in vivo perivascular niche environment during tissue repair may provide information about the biological function and contribution of progenitor cells to postnatal vasculogenesis, thereby enhancing their therapeutic potential.

AIM

We established a fibrin-based xeno-free human 3D in vitro vascular niche model to study the interaction of mesenchymal stromal cells (MSC) with peripheral blood mononuclear cells (PBMC) including circulating progenitor cells in the absence of endothelial cells (EC), and to investigate the contribution of this cross-talk to neo-vessel formation.

MATERIALS AND METHODS

Bone marrow-derived MSC were co-cultured with whole PBMC, enriched monocytes (Mo), enriched T cells, and Mo together with T cells, respectively, obtained from leukocyte reduction chambers generated during the process of single-donor platelet apheresis. Cells were embedded in 3D fibrin matrices, using exclusively human-derived culture components without external growth factors. Cytokine secretion was analyzed in supernatants of 3D cultures by cytokine array, vascular endothelial growth factor (VEGF) secretion was quantified by ELISA. Cellular and structural re-arrangements were characterized by immunofluorescence and confocal laser-scanning microscopy of topographically intact 3D fibrin gels.

RESULTS

3D co-cultures of MSC with PBMC, and enriched Mo together with enriched T cells, respectively, generated, within 2 weeks, complex CD31+/CD34+ vascular structures, surrounded by basement membrane collagen type-IV+ cells and matrix, in association with increased VEGF secretion. PBMC contained CD31+CD34+CD45dimCD14- progenitor-type cells, and EC of neo-vessels were PBMC-derived. Vascular structures showed intraluminal CD45+ cells that underwent apoptosis thereby creating a lumen. Cross-talk of MSC with enriched Mo provided a pro-angiogenic paracrine environment. MSC co-cultured with enriched T cells formed "cell-in-cell" structures generated through internalization of T cells by CD31+CD45 dim⁣/ - cells. No vascular structures were detected in co-cultures of MSC with either Mo or T cells.

CONCLUSION

Our xeno-free 3D in vitro vascular niche model demonstrates that a complex synergistic network of cellular, extracellular and paracrine cross-talk can contribute to de novo vascular development through self-organization via co-operation of immune cells with blood-derived progenitor cells and MSC, and thereby may open a new perspective for advanced vascular tissue engineering in regenerative medicine.

Continuous Electrical Stimulation Affects Initial Growth and Proliferation of Adipose-Derived Stem Cells

The aim of the study was to establish electrical stimulation parameters in order to improve cell growth and viability of human adipose-derived stem cells (hADSC) when compared to non-stimulated cells in vitro. hADSC were exposed to continuous electrical stimulation with 1.7 V AC/20 Hz. After 24, 72 h and 7 days, cell number, cellular surface coverage and cell proliferation were assessed. In addition, cell cycle analysis was carried out after 3 and 7 days. After 24 h, no significant alterations were observed for stimulated cells. At day 3, stimulated cells showed a 4.5-fold increase in cell numbers, a 2.7-fold increase in cellular surface coverage and a significantly increased proliferation. Via cell cycle analysis, a significant increase in the G2/M phase was monitored for stimulated cells. Contrastingly, after 7 days, the non-stimulated group exhibited a 11-fold increase in cell numbers and a 4-fold increase in cellular surface coverage as well as a significant increase in cell proliferation. Moreover, the stimulated cells displayed a shift to the G1 and sub-G1 phase, indicating for metabolic arrest and apoptosis initiation. In accordance, continuous electrical stimulation of hADSC led to a significantly increased cell growth and proliferation after 3 days. However, longer stimulation periods such as 7 days caused an opposite result indicating initiation of apoptosis.

Effects of Conditioned Medium from Bone Marrow Cells on Human Umbilical Cord Perivascular Cells

Mesenchymal cells derived from human umbilical cord tissue are attracting increasing attention as a source for cell therapy. However, for applying the same in tissue engineering, it has been shown that the differentiation capacity of mesenchymal stromal cells (MSCs) is influenced by the tissue from which the cells are harvested. Thus, to explore the possibility of increasing the osteogenic capacity of MSCs derived from the perivascular tissue of the human umbilical cord (human umbilical cord perivascular cells, HUCPVCs), we cultured these cells using conditioned medium (CM) derived from cultures of human bone marrow-derived mesenchymal stromal cells (hBMMSCs). However, hBM-CM contains a wide variety of growth factors, the amounts and ratios of which are considered to vary with the cell culture stage. Thus, we aimed to evaluate the effects of hBM-CM derived from different stages of hBMMSC culture on the osteogenic capacity of HUCPVCs. The stages of hBMMSC culture were defined as follows: Stage 1 (mitogenic stage) represented the period from the start of hBMMSC culture to 70% cell confluence; Stage 2 (confluent stage) represented the period from 70% confluence to the initiation of calcified nodule formation; and Stage 3 (calcification stage) represented the period following the initiation of calcified nodule formation. An analysis of growth factors contained in the CM obtained at each stage by enzyme-linked immunosorbent assay showed that insulin-like growth factor 1 (IGF-1) was significantly elevated at Stage 2, whereas vascular endothelial growth factor (VEGF) was significantly elevated at Stage 3. HUCPVCs were cultured using the CM from each of the stages for 1, 2, or 3 weeks. RUNX2 expression was the most upregulated at week 1 and then downregulated in all the groups. The expression of collagen 1 was significantly elevated in Stage 2 HUCs at week 3. Alkaline phosphatase (ALP) activity, ALP, and alizarin staining were higher in Stage 2 HUCs and Stage 3 HUCs. The calcium content was the highest in Stage 2 HUCs. The calcium content of HUCPVC obtained by the method used in this study was six times higher than that reported in the previous study. Collectively, our results show that the CM obtained at Stage 2 was most effective in driving the osteogenic differentiation of HUCPVCs. Impact Statement Mesenchymal stromal cells (MSCs) derived from the perivascular tissue of umbilical cords are promising candidates for regenerative medicine. Because these are able to be differentiated into bone cells, cartilage cells, and adipocytes. The number of MSCs in perivascular tissue (HUCPVCs) is ∼1/300 but the number of HUCPVCs that differentiates into osteogenic cells is quite low. In order to promote osteogenic differentiation of HUCPVCs, we cultured HUCPVCs using conditioned medium collected from human bone marrow-derived mesenchymal stromal cells. Our study suggests that the use of conditioned medium can be effective on inducing osteogenic differentiation of HUCPVCs.

Mesenchymal or Maintenance Stem Cell & Understanding Their Role in Osteoarthritis of the Knee Joint: A Review Article

Mesenchymal Stem Cell (MSC) therapy in osteoarthritis has been hailed as a promising treatment for osteoarthritis due to their unlimited potential of healing and regeneration. Existing literature regarding their proper name, optimal sources, mechanisms of action, dosage, and route of administration, efficacy, and safety is debatable. This index review article has tried to connect these puzzling pieces of available information and brought clarity on some of these crucial issues. The author believes that Maintenance Stem Cells (MSC) may be a more suitable term than mesenchymal stem cell or medicinal signaling cells as their origin might not be limited to mesodermal tissue. Also, they have been shown capable of self-renewal, differentiation, and maintaining a cascade of healing & possibly regeneration at the implanted site. Only a small percentage of implanted MSC survive and rest undergo apoptosis after releasing growth factors, cytokines, and extracellular vesicles. These surviving MSC become active due to conformational changes induced by anti-environment stimuli and undergo limited self-renewal, proliferation, and differentiation, but only a few of them might incorporate into the host tissues. These cells generate & maintain a momentum of series of regenerative activities to improve the function of joint, stabilize or possibly enhance the cartilage quality. More randomized studies with long term follow-up are required to bring clarity on their ideal source, expansion, culture technique, optimum dosage, and route of administration and long-term safety issues.

Augmenting emergency granulopoiesis with CpG conditioned mesenchymal stromal cells in murine neutropenic sepsis

Patients with immune deficiencies from cancers and associated treatments represent a growing population within the intensive care unit with increased risk of morbidity and mortality from sepsis. Mesenchymal stromal cells (MSCs) are an integral part of the hematopoietic niche and express toll-like receptors, making them candidate cells to sense and translate pathogenic signals into an innate immune response. In this study, we demonstrate that MSCs administered therapeutically in a murine model of radiation-associated neutropenia have dual actions to confer a survival benefit in Pseudomonas aeruginosa pneumo-sepsis that is not from improved bacterial clearance. First, MSCs augment the neutrophil response to infection, an effect that is enhanced when MSCs are preconditioned with CpG oligodeoxynucleotide, a toll-like receptor 9 agonist. Using cytometry by time of flight, we identified proliferating neutrophils (Ly6GlowKi-67+) as the main expanded cell population within the bone marrow. Further analysis revealed that CpG-MSCs expand a lineage restricted progenitor population (Lin-Sca1+C-kit+CD150-CD48+) in the bone marrow, which corresponded to a doubling in the myeloid proliferation and differentiation potential in response to infection compared with control. Despite increased neutrophils, no reduction in organ bacterial count was observed between experimental groups. However, the second effect exerted by CpG-MSCs is to attenuate organ damage, particularly in the lungs. Neutrophils obtained from irradiated mice and cocultured with CpG-MSCs had decreased neutrophil extracellular trap formation, which was associated with decreased citrullinated H3 staining in the lungs of mice given CpG-MSCs in vivo. Thus, this preclinical study provides evidence for the therapeutic potential of MSCs in neutropenic sepsis.

Positive early clinical outcomes of bone marrow aspirate concentrate for osteoarthritis using a novel fenestrated trocar

BACKGROUND

This study sought to assess early clinical outcomes for knee osteoarthritis (OA) patients undergoing bone marrow aspirate concentrate (BMAC) treatment using a novel closed-end, fenestrated trocar (FT) that does not require centrifugation.

METHODS

A prospective cohort of 17 knee OA patients undergoing BMAC treatment with the FT system from March 2018 to March 2019 was retrospectively evaluated. Approximately 10 mL of BMAC was harvested, no centrifugation was performed, and the BMAC was injected into the affected knee. Clinical outcomes were assessed at baseline, six weeks, and 12 weeks. This study has no affiliation with/vested-interest in the FT system.

RESULTS

There were significant improvements in nearly all outcomes from baseline to 12 weeks. Specific improvements included Knee Injury and OA Outcome Score (KOOS) activities-of-daily-living (61.1 ± 9.2 [mean ± 95% confidence interval] to 89.3 ± 6, p = 0.001), quality-of-life (32.7 ± 9.3 to 66.1 ± 17.9, p = 0.003), sports/recreation (36.9 ± 10.6 to 72.6 ± 26.3, p = 0.006), and pain (53.8 ± 9.3 to 83 ± 10.2, p = 0.001); Lysholm scores (55.5 ± 8.4 to 77.3 ± 10.5, p = 0.009); and visual analog pain scores (5.68 ± 1.14 to 2.07 ± 1.86, p = 0.003). Individually, at least 75% of patients exhibited improvement in all KOOS categories at six weeks and at least 85% at 12 weeks.

CONCLUSIONS

BMAC treatment with an FT system that does not require centrifugation resulted in significant improvements in early pain and function scores for knee OA. The symptomatic improvements in this study were similar to or greater than what has been reported using traditional needles. These data may provide clinicians with comfort in using an FT system and provide motivation for future randomized-controlled trials comparing aspiration techniques.

Defining a Regulatory Strategy for ATMP/Aerosol Delivery Device Combinations in the Treatment of Respiratory Disease

Advanced Therapeutic Medicinal Products (ATMP) are a heterogenous group of investigational medicinal products at the forefront of innovative therapies with direct applicability in respiratory diseases. ATMPs include, but are not limited to, stem cells, their secretome, or extracellular vesicles, and each have shown some potential when delivered topically within the lung. This review focuses on that subset of ATMPs. One key mode of delivery that has enabling potential in ATMP validation is aerosol-mediated delivery. The selection of the most appropriate aerosol generator technology is influenced by several key factors, including formulation, patient type, patient intervention, and healthcare economics. The aerosol-mediated delivery of ATMPs has shown promise for the treatment of both chronic and acute respiratory disease in pre-clinical and clinical trials; however, in order for these ATMP device combinations to translate from the bench through to commercialization, they must meet the requirements set out by the various global regulatory bodies. In this review, we detail the potential for ATMP utility in the lungs and propose the nebulization of ATMPs as a viable route of administration in certain circumstances. Further, we provide insight to the current regulatory guidance for nascent ATMP device combination product development within the EU and US.

Mesenchymal Stem Cell Secretome as an Emerging Cell-Free Alternative for Improving Wound Repair

The use of mesenchymal stem cells (MSC) for the treatment of cutaneous wounds is currently of enormous interest. However, the broad translation of cell therapies into clinical use is hampered by their efficacy, safety, manufacturing and cost. MSCs release a broad repertoire of trophic factors and immunomodulatory cytokines, referred to as the MSC secretome, that has considerable potential for the treatment of cutaneous wounds as a cell-free therapy. In this review, we outline the current status of MSCs as a treatment for cutaneous wounds and introduce the potential of the MSC secretome as a cell-free alternative for wound repair. We discuss the challenges and provide insights and perspectives for the future development of the MSC secretome as well as identify its potential clinical translation into a therapeutic treatment.

Pulsed focused ultrasound enhances the therapeutic effect of mesenchymal stromal cell-derived extracellular vesicles in acute kidney injury

BACKGROUND

Acute kidney injury (AKI) is characterized by rapid failure of renal function and has no curative therapies. Mesenchymal stromal cell (MSC)-derived extracellular vesicles (EVs) are known to carry therapeutic factors, which have shown promise in regenerative medicine applications, including AKI. However, there remains an unmet need to optimize their therapeutic effect. One potential avenue of optimization lies in pulsed focused ultrasound (pFUS), where tissues-of-interest are treated with sound waves. pFUS has been shown to enhance MSC therapy via increased cell homing, but its effects on cell-free EV therapy remain largely unexplored.

METHODS

We combine pFUS pretreatment of the kidney with MSC-derived EV therapy in a mouse model of cisplatin-induced AKI.

RESULTS

EVs significantly improved kidney function, reduced injury markers, mediated increased proliferation, and reduced inflammation and apoptosis. While pFUS did not enhance EV homing to the kidney, the combined treatment resulted in a superior therapeutic effect compared to either treatment alone. We identified several molecular mechanisms underlying this synergistic therapeutic effect, including upregulation of proliferative signaling (MAPK/ERK, PI3K/Akt) and regenerative pathways (eNOS, SIRT3), as well as suppression of inflammation.

CONCLUSION

Taken together, pFUS may be a strategy for enhancing the therapeutic efficacy of MSC-derived EV treatment for the treatment of AKI.

Tissue-specific angiogenic and invasive properties of human neonatal thymus and bone MSCs: Role of SLIT3-ROBO1

Although mesenchymal stem/stromal cells (MSCs) are being explored in numerous clinical trials as proangiogenic and proregenerative agents, the influence of tissue origin on the therapeutic qualities of these cells is poorly understood. Complicating the functional comparison of different types of MSCs are the confounding effects of donor age, genetic background, and health status of the donor. Leveraging a clinical setting where MSCs can be simultaneously isolated from discarded but healthy bone and thymus tissues from the same neonatal patients, thereby controlling for these confounding factors, we performed an in vitro and in vivo paired comparison of these cells. We found that both neonatal thymus (nt)MSCs and neonatal bone (nb)MSCs expressed different pericytic surface marker profiles. Further, ntMSCs were more potent in promoting angiogenesis in vitro and in vivo and they were also more motile and efficient at invading ECM in vitro. These functional differences were in part mediated by an increased ntMSC expression of SLIT3, a factor known to activate endothelial cells. Further, we discovered that SLIT3 stimulated MSC motility and fibrin gel invasion via ROBO1 in an autocrine fashion. Consistent with our findings in human MSCs, we found that SLIT3 and ROBO1 were expressed in the perivascular cells of the neonatal murine thymus gland and that global SLIT3 or ROBO1 deficiency resulted in decreased neonatal murine thymus gland vascular density. In conclusion, ntMSCs possess increased proangiogenic and invasive behaviors, which are in part mediated by the paracrine and autocrine effects of SLIT3.

DNA damage repair response in mesenchymal stromal cells: From cellular senescence and aging to apoptosis and differentiation ability

Mesenchymal stromal cells (MSCs) are heterogeneous and contain several populations, including stem cells. MSCs' secretome has the ability to induce proliferation, differentiation, chemo-attraction, anti-apoptosis, and immunomodulation activities in stem cells. Moreover, these cells recognize tissue damage caused by drugs, radiation (e.g., Ultraviolet, infra-red) and oxidative stress, and respond in two ways: either MSCs differentiate into particular cell lineages to preserve tissue homeostasis, or they release a regenerative secretome to activate tissue repairing mechanisms. The maintenance of MSCs in quiescence can increase the incidence and accumulation of various forms of genomic modifications, particularly upon environmental insults. Thus, dysregulated DNA repair pathways can predispose MSCs to senescence or apoptosis, reducing their stemness and self-renewal properties. For instance, DNA damage can impair telomere replication, activating DNA damage checkpoints to maintain MSC function. In this review, we aim to summarize the role of DNA damage and associated repair responses in MSC senescence, differentiation and programmed cell death.

Inflammation-mediated age-dependent effects of casein kinase 2-interacting protein-1 on osteogenesis in mesenchymal stem cells

BACKGROUND

The casein kinase 2-interacting protein-1 (CKIP-1) is important in the development of osteoblasts and cardiomyocytes. However, the effects of CKIP-1 on osteoblast precursor mesenchymal stem cells (MSCs) remain unclear. This study aimed to determine whether CKIP-1 affects osteogenic differentiation in MSCs and explore the relationship of CKIP-1 and inflammation.

METHODS

Bone marrow MSCs of CKIP-1 wild type (WT) and knockout (KO) mice were cultivated in vitro. Cell phenotype was analyzed by flow cytometry, colony formation was detected to study the proliferative ability. Osteogenic and adipogenic induction were performed. The osteogenic ability was explored by alizarin red staining, alkaline phosphatase (ALP) staining and ALP activity detection. Quantitative real-time polymerase chain reaction (qRT-PCR) was carried out to determine the mRNA expression levels of osteoblast marker genes. The adipogenic ability was detected by oil red O staining. Content of the bone was analyzed to observe the differences of bone imaging parameters including trabecular bone volume/tissue volume (BV/TV), bone surface area fraction/trabecular BV, trabecular number (Tb.N), and trabecular spacing (Tb.sp). Interleukin (IL)-1β was injected on WT mice of 2 months old and 18 months old, respectively. Difference in CKIP-1 expression was detected by RT-PCR and western blot. The relationship between CKIP-1 and inflammation was explored by RT-PCR and western blot.

RESULTS

ALP assays, alizarin red staining, and qRT-PCR showed that MSCs derived from CKIP-1 KO mice exhibited a stronger capability for osteogenesis. Micro-computed tomography detection showed that among 18-month-old mice, CKIP-1 KO mice presented significantly higher bone mass compared with WT mice (P = 0.02). No significant difference was observed in 2-month-old mice. In vivo data showed that expression of CKIP-1 was higher in the bone marrow of aging mice than in young mice (4.3-fold increase at the mRNA level, P = 0.04). Finally, the expression levels of CKIP-1 in bone marrow (3.2-fold increase at the mRNA level, P = 0.03) and cultured MSCs were up-regulated on chronic inflammatory stimulation by IL-1β.

CONCLUSIONS

CKIP-1 is responsible for negative regulation of MSC osteogenesis with age-dependent effects. Increasing levels of inflammation with aging may be the primary factor responsible for higher expression levels of CKIP-1 but may not necessarily affect MSC aging.

A transcriptomic analysis of serial-cultured, tonsil-derived mesenchymal stem cells reveals decreased integrin α3 protein as a potential biomarker of senescent cells

Background

Mesenchymal stem cells (MSCs) have been widely used for stem cell therapy, and serial passage of stem cells is often required to obtain sufficient cell numbers for practical applications in regenerative medicine. A long-term serial cell expansion can potentially induce replicative senescence, which leads to a progressive decline in stem cell function and stemness, losing multipotent characteristics. To improve the therapeutic efficiency of stem cell therapy, it would be important to identify specific biomarkers for senescent cells.

Methods

Tonsil-derived mesenchymal stem cells (TMSCs) with 20–25 passages were designated as culture-aged TMSCs, and their mesodermal differentiation potentials as well as markers of senescence and stemness were compared with the control TMSCs passaged up to 8 times at the most (designated as young). A whole-genome analysis was used to identify novel regulatory factors that distinguish between the culture-aged and control TMSCs. The identified markers of replicative senescence were validated using Western blot analyses.

Results

The culture-aged TMSCs showed longer doubling time compared to control TMSCs and had higher expression of senescence-associated (SA)-β-gal staining but lower expression of the stemness protein markers, including Nanog, Oct4, and Sox2 with decreased adipogenic, osteogenic, and chondrogenic differentiation potentials. Microarray analyses identified a total of 18,614 differentially expressed genes between the culture-aged and control TMSCs. The differentially expressed genes were classified into the Gene Ontology categories of cellular component (CC), functional component (FC), and biological process (BP) using KEGG (Kyoto encyclopedia of genes and genomes) pathway analysis. This analysis revealed that those genes associated with CC and BP showed the most significant difference between the culture-aged and control TMSCs. The genes related to extracellular matrix-receptor interactions were also shown to be significantly different (p < 0.001). We also found that culture-aged TMSCs had decreased expressions of integrin α3 (ITGA3) and phosphorylated AKT protein (p-AKT-Ser⁴⁷³) compared to the control TMSCs.

Conclusions

Our data suggest that activation of ECM-receptor signaling, specifically involved with integrin family-mediated activation of the intracellular cell survival-signaling molecule AKT, can regulate stem cell senescence in TMSCs. Among these identified factors, ITGA3 was found to be a representative biomarker of the senescent TMSCs. Exclusion of the TMSCs with the senescent TMSC markers in this study could potentially increase the therapeutic efficacy of TMSCs in clinical applications.

Determining How Human Mesenchymal Stem Cells Change Their Degradation Strategy in Response to Microenvironmental Stiffness

During the wound healing process, human mesenchymal stem cells (hMSCs) are recruited to the injury where they regulate inflammation and initiate healing and tissue regeneration. To aid in healing, synthetic cell-laden hydrogel scaffolds are being designed to deliver additional hMSCs to wounds to enhance or restart the healing process. These scaffolds are being designed to mimic native tissue environments, which include physical cues, such as scaffold stiffness. In this work, we focus on how the initial scaffold stiffness hMSCs are encapsulated in changes cell-mediated remodeling and degradation and motility. To do this, we encapsulate hMSCs in a well-defined synthetic hydrogel scaffold that recapitulates aspects of the native extracellular matrix (ECM). We then characterize cell-mediated degradation in the pericellular region as a function of initial microenvironmental stiffness. Our hydrogel consists of a 4-arm poly(ethylene glycol) (PEG) end-functionalized with norbornene which is chemically cross-linked with a matrix metalloproteinase (MMP) degradable peptide sequence. This peptide sequence is cleaved by hMSC-secreted MMPs. The hydrogel elastic modulus is varied from 80 to 2400 Pa by changing the concentration of the peptide cross-linker. We use multiple particle tracking microrheology (MPT) to characterize the spatiotemporal cell-mediated degradation in the pericellular region. In MPT, fluorescently labeled particles are embedded in the material, and their Brownian motion is measured. We measure an increase in cell-mediated degradation and remodeling as the post-encapsulation time increases. MPT also measures changes in the degradation profile in the pericellular region as hydrogel stiffness is increased. We hypothesize that the change in the degradation profile is due to a change in the amount and type of molecules secreted by hMSCs. We also measure a significant decrease in cell speed as hydrogel stiffness increases due to the increased physical barrier that needs to be degraded to enable motility. These measurements increase our understanding of the rheological changes in the pericellular region in different physical microenvironments which could lead to better design of implantable biomaterials for cell delivery to wounded areas.

Cell Therapy for Ischemic Stroke: How to Turn a Promising Preclinical Research into a Successful Clinical Story

Stroke is a major public health issue with limited treatment. The pharmacologically or mechanically removing of the clot is accessible to less than 10% of the patients. Stem cell therapy is a promising alternative strategy since it increases the therapeutic time window but many issues remain unsolved. To avoid a new dramatic failure when translating experimental data on the bedside, this review aims to highlight the indispensable checkpoints to make a successful clinical trial based on the current preclinical literature. The large panel of progenitors/ stem cells at the researcher's disposal is to be used wisely, regarding the type of cells, the source of cells, the route of delivery, the time window, since it will directly affect the outcome. Mechanisms are still incompletely understood, although recent studies have focused on the inflammation modulation of most cells types.

Effect of autologous adipose-derived mesenchymal stem cell therapy in the treatment of an osteochondral lesion of the ankle

Osteochondral lesions (OCLs) of the talus are rare but can be associated with significant morbidity and may lead to the development of osteoarthritis. An improved understanding of the action of mesenchymal stem cells (MSCs) has seen renewed interest in their role in cartilage repair, with early preclinical and clinical research showing benefits in symptomatic and structural improvement. A 42-year-old man presented with an unstable OCL of the talus and onset of early osteoarthritis with a history of multiple previous ankle arthroscopies for ankle impingement. The patient underwent arthroscopic removal of the OCL in combination with adipose-derived MSC therapy. The patient reported progressive improvement as measured by the validated Foot and Ankle Disability Index. Repeat MRI with additional T2 mapping techniques showed successful regeneration of hyaline-like cartilage. This case is the first to show the successful use of MSC therapy in the management of an ankle OCL. Trial registration: Australian New Zealand Clinical Trials Registry - ACTRN12617000638336.

Effect of autologous adipose-derived mesenchymal stem cell therapy in combination with autologous platelet-rich plasma in the treatment of elbow tendinopathy

Tendinopathy is a common condition of both the athletic and general population and can be associated with significant pain and disability. The ability of mesenchymal stem cells (MSCs) to differentiate along a mesodermal cell lineage, including tenocytes, and secrete various bioactive regenerative and anti-inflammatory molecules has seen them considered as a future reparative therapy for tendinopathy. Preclinical trials with MSCs have shown promising positive functional and structural outcomes in several connective tissue related conditions. A 52-year-old male professional masters golfer presents with a clinical history of common extensor origin tendinopathy of the elbow. Subsequent formal ultrasound showed evidence of a large intrasubstance tear. The patient underwent intratendinous autologous adipose-derived MSC therapy in combination with autologous platelet-rich plasma. Following treatment, the patient reported progressive improvement as measured by the validated Numeric Pain Rating Scale and Patient-Rated Tennis Elbow Evaluation score. Repeat imaging showed successful regeneration of tendon-like tissue.

Mesenchymal Stromal Cell-Based Therapy-An Alternative to Arthroplasty for the Treatment of Osteoarthritis? A State of the Art Review of Clinical Trials

Osteoarthritis (OA) is the most common degenerative joint disorder worldwide and to date no regenerative treatment has been established in clinical practice. This review evaluates the current literature on the clinical translation of mesenchymal stromal cell (MSC)-based therapy in OA management with a focus on safety, outcomes and procedural specifics. PubMed, Cochrane Library and clinicaltrials.gov were searched for clinical studies using MSCs for OA treatment. 290 articles were initially identified and 42 articles of interest, including a total of 1325 patients, remained for further examination. Most of the included studies used adipose tissue-derived MSCs or bone-marrow-derived MSCs to treat patients suffering from knee OA. MSC-based therapy for knee OA appears to be safe and presumably effective in selected parameters. Yet, a direct comparison between studies was difficult due to a pronounced variance regarding methodology, assessed outcomes and evidence levels. Intensive scientific engagement is needed to identify the most effective source and dosage of MSCs for OA treatment in the future. Consent on outcome measures has to be reached and eventually patient sub-populations need to be identified that will profit most from MSC-based treatment for OA.

High tibial osteotomy with human umbilical cord blood-derived mesenchymal stem cells implantation for knee cartilage regeneration

BACKGROUND

High tibial osteotomy (HTO) is a well-established method for the treatment of medial compartment osteoarthritis of the knee with varus deformity. However, HTO alone cannot adequately repair the arthritic joint, necessitating cartilage regeneration therapy. Cartilage regeneration procedures with concomitant HTO are used to improve the clinical outcome in patients with varus deformity.

AIM

To evaluate cartilage regeneration after implantation of allogenic human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) with concomitant HTO.

METHODS

Data for patients who underwent implantation of hUCB-MSCs with concomitant HTO were evaluated. The patients included in this study were over 40 years old, had a varus deformity of more than 5°, and a full-thickness International Cartilage Repair Society (ICRS) grade IV articular cartilage lesion of more than 4 cm² in the medial compartment of the knee. All patients underwent second-look arthroscopy during hardware removal. Cartilage regeneration was evaluated macroscopically using the ICRS grading system in second-look arthroscopy. We also assessed the effects of patient characteristics, such as trochlear lesions, age, and lesion size, using patient medical records.

RESULTS

A total of 125 patients were included in the study, with an average age of 58.3 ± 6.8 years (range: 43-74 years old); 95 (76%) were female and 30 (24%) were male. The average hip-knee-ankle (HKA) angle for measuring varus deformity was 7.6° ± 2.4° (range: 5.0-14.2°). In second-look arthroscopy, the status of medial femoral condyle (MFC) cartilage was as follows: 73 (58.4%) patients with ICRS grade I, 37 (29.6%) with ICRS grade II, and 15 (12%) with ICRS grade III. No patients were staged with ICRS grade IV. Additionally, the scores [except International Knee Documentation Committee (IKDC) at 1 year] of the ICRS grade I group improved more significantly than those of the ICRS grade II and III groups.

CONCLUSION

Implantation of hUCB-MSCs with concomitant HTO is an effective treatment for patients with medial compartment osteoarthritis and varus deformity. Regeneration of cartilage improves the clinical outcomes for the patients.

Mesenchymal Stromal Cell Bioreactor for Ex Vivo Reprogramming of Human Immune Cells

Bone marrow mesenchymal stromal cells (MSCs) have been studied for decades as potent immunomodulators. Clinically, they have shown some promise but with limited success. Here, we report the ability of a scalable hollow fiber bioreactor to effectively maintain ideal MSC function as a single population while also being able to impart an immunoregulatory effect when cultured in tandem with an inflamed lymphocyte population. MSCs were seeded on the extraluminal side of hollow fibers within a bioreactor where they indirectly interact with immune cells flowing within the lumen of the fibers. MSCs showed a stable and predictable metabolite and secreted factor profile during several days of perfusion culture. Exposure of bioreactor-seeded MSCs to inflammatory stimuli reproducibly switched MSC secreted factor profiles and altered microvesicle composition. Furthermore, circulating, activated human peripheral blood mononuclear cells (PBMCs) were suppressed by MSC bioreactor culture confirmed by a durable change in their immunophenotype and function. This platform was useful to study a model of immobilized MSCs and circulating immune cells and showed that monocytes play an important role in MSC driven immunomodulation. This coculture technology can have broad implications for use in studying MSC-immune interactions under flow conditions as well as in the generation of ex vivo derived immune cellular therapeutics.

Characterization of a pluripotent stem cell-derived matrix with powerful osteoregenerative capabilities

Approximately 10% of fractures will not heal without intervention. Current treatments can be marginally effective, costly, and some have adverse effects. A safe and manufacturable mimic of anabolic bone is the primary goal of bone engineering, but achieving this is challenging. Mesenchymal stem cells (MSCs), are excellent candidates for engineering bone, but lack reproducibility due to donor source and culture methodology. The need for a bioactive attachment substrate also hinders progress. Herein, we describe a highly osteogenic MSC line generated from induced pluripotent stem cells that generates high yields of an osteogenic cell-matrix (ihOCM) in vitro. In mice, the intrinsic osteogenic activity of ihOCM surpasses bone morphogenic protein 2 (BMP2) driving healing of calvarial defects in 4 weeks by a mechanism mediated in part by collagen VI and XII. We propose that ihOCM may represent an effective replacement for autograft and BMP products used commonly in bone tissue engineering.

Production of a safe and manufacturable material to mimic anabolic bone for tissue engineering has been hard to achieve to date. Here the authors use a mesenchymal stem cell line generated from induced pluripotent stem cells to produce osteogenic cell-matrix, displaying significant healing properties in mice.

Recovery of motricity and micturition after transplantation of mesenchymal stem cells in rats subjected to spinal cord injury

The objective was to evaluate the effect of human adipose-derived stem cell (hADSC) infusion on impaired hindlimb function and urinary continence after spinal cord contusion in rats. hADSCs were transplanted into the injured spinal cords of rats 7 and 14 days after injury in two groups (B and C). Group C also received methylprednisolone sodium succinate (MPSS) after 3 h of injury. The control group (group A) did not receive corticoids or stem cells. Voiding and motor performance evaluations were performed daily for 90 days post-transplantation. Cells were labeled with PKH26 or PKH67 for in vitro monitoring. For in vivo screening, the cells were evaluated for bioluminescence. The levels of some cytokines were quantified in different times. Euthanasia was performed 90 days post-transplant. β-tubulin III expression was evaluated in the spinal cord of the animals from all groups. As a result, we observed a recovery of 66.6 % and 61.9 % in urinary continence of animals from groups B and C, respectively. Partial recovery of motor was observed in 23.8 % and 19 % of the animals from groups B and C, respectively. Cells remained viable at the site up to 90 days after transplantation. No significant difference was observed in levels of cytokines and thickness of urinary bladders between groups. A smaller percentage of tissue injury and higher concentrations of neuropils were observed in the spinal cords of the animals from groups B and C than control group. Thus, hADSCs transplantation with or without MPSS, contributed to the improvement in voiding and motor performance of Wistar rats submitted to compressive spinal cord injury.

Oriented immobilization of basic fibroblast growth factor: Bioengineered surface design for the expansion of human mesenchymal stromal cells

E. coli expressed recombinant basic fibroblast growth factor (bFGF) with histidine-tag (bFGF-His) was immobilized onto the surface of a glass plate modified with a Ni(II)-chelated alkanethiol monolayer. The immobilization is expected to take place through the coordination between Ni(II) and His-tag. The bFGF-immobilized surface was exposed to citrate buffer solution to refold in situ the surface-immobilized bFGF. The secondary structure of immobilized bFGF-His was analyzed by solid-phase circular dichroism (CD) spectroscopy. Immortalized human mesenchymal stromal cells (hMSCs) were cultured on the bFGF-His-immobilized surface to examine their proliferation. CD spectroscopy revealed that the immobilized bFGF initially exhibited secondary structure rich in α-helix and that the spectrum was gradually transformed to exhibit the formation of β-strands upon exposure to citrate buffer solution, approaching to the spectrum of native bFGF. The rate of hMSC proliferation was 1.2-fold higher on the bFGF-immobilized surface treated with in situ citrate buffer, compared to the polystyrene surface. The immobilized bFGF-His treated in situ with citrate buffer solution seemed to be biologically active because its secondary structure approached its native state. This was well demonstrated by the cell culture experiments. From these results we conclude that immobilization of bFGF on the culture substrate serves to enhance proliferation of hMSCs.

Effect of bone marrow mesenchymal stem cells on perforator skin flap survival area in rats

Trans-territory perforator flaps are commonly used to reconstruct large defects of the soft tissues. The distal portion of the flap often becomes necrotic, however, as a result of the jeopardised vasculature of choke zone II. The trophic and vascular regenerative properties of bone marrow mesenchymal stem cells (BMSC) seemed to be a promising approach to prevent flaps becoming ischaemic. The purpose of our study is to evaluate the effects of BMSC on the survival of the three-territory perforator flap. The flap model was created based on the deep circumflex iliac vessel in rats. Eighteen rats were distributed, at random, into three groups. Immediately after the flaps were placed, groups were respectively given a single panniculus carnosus injection at choke zone II of either 1×10⁵ (BMSCs^low), 1×10⁶ (BMSCs^hig) BMSC, or phosphate-buffered saline (PBS). On postoperative day seven, we assessed the gross view of the flap and survival. We also evaluated microvessels by histological examination and angiogenesis-related gene expression by quantitative real-time polymerase chain reaction. After high dosage of BMSC, the flap survival rate, diameter and density of microvessels, vascular endothelial growth factor (VEGF) and platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) levels were significantly higher in the BMSC treatment group than the control group. We therefore confirmed the positive effects of BMSC on the survival of multi-territory perforator flaps.

Intraovarian injection of mesenchymal stem cells improves oocyte yield and in vitro embryo production in a bovine model of fertility loss

Valuable female cattle are continuously subject to follicular puncture (ovum pick-up - OPU). This technique is commonly used for in-vitro embryo production, but may result in ovarian lesion. Mesenchymal stem cells (MSC) ameliorate the function of injured tissues, but their use to treat ovarian lesions in cattle has not been established. We investigated whether a local injection of MSC would reduce the negative effects of repeated OPU under acute and chronic scenarios in bovines. First, we performed four OPU sessions and injected 2.5 × 106 MSCs immediately after the 4th OPU procedure (n = 5). The treated organs (right ovary) were compared to their saline-treated counterparts (left), and presented superior production of oocytes and embryos in the three following OPU sessions (P < 0.05). Then, cows with progressive fertility loss went through three OPU sessions. Animals received MSC, saline, or MSC + FSH in both ovaries after the first OPU. In the two following OPU sessions, the MSC and MSC + FSH - treated groups failed to present any significant alteration in the number of oocytes and embryos compared to saline-treated animals. Thus, MSC have beneficial effects on the fertility of OPU-lesioned cows, but not in cows with cystic ovarian disease and chronic ovarian lesions.

Mesenchymal stem cell use in acute respiratory distress syndrome: a potential therapeutic application

Acute respiratory distress syndrome (ARDS) is a condition of acute respiratory failure resulting from noncardiogenic pulmonary edema. It may occur as a consequence of lung infection, sepsis, trauma, aspiration or drug reaction. The pathogenesis of ARDS is understood to be an unregulated inflammatory cascade with both endothelial and epithelial layer damage leading to alveolar fluid collection and pulmonary edema. Despite improved understanding of the cause of ARDS, treatment remains supportive with a mortality rate ranging from 25–40%. Preclinical and early phase clinical trials have highlighted the potential role of mesenchymal stem cells in combating the inflammatory cascade through immunomodulatory mechanisms and assisting in tissue repair.

Acute respiratory distress syndrome (ARDS) is a condition of sudden respiratory failure due to fluid in the lungs as a consequence of factors such as trauma and bacterial or viral lung infections. ARDS is understood to occur as a result of uncontrolled inflammation. Conventional treatment is supportive only with ARDS having a high death rate of up to 40%. Evidence from both preclinical and clinical trials highlight the potential role of mesenchymal stem cells in combating the inflammatory reactions that cause ARDS as this therapy both modifies the immune response and provides assistance with tissue repair.

Cell-based therapies for the treatment of myocardial infarction: lessons from cardiac regeneration and repair mechanisms in non-human vertebrates

Ischemic cardiomyopathy is the cardiovascular condition with the highest impact on the Western population. In mammals (humans included), prolonged ischemia in the ventricular walls causes the death of cardiomyocytes (myocardial infarction, MI). The loss of myocardial mass is soon compensated by the formation of a reparative, non-contractile fibrotic scar that ultimately affects heart performance. Despite the enormous clinical relevance of MI, no effective therapy is available for the long-term treatment of this condition. Moreover, since the human heart is not able to undergo spontaneous regeneration, many researchers aim at designing cell-based therapies that allow for the substitution of dead cardiomyocytes by new, functional ones. So far, the majority of such strategies rely on the injection of different progenitor/stem cells to the infarcted heart. These cardiovascular progenitors, which are expected to differentiate into cardiomyocytes de novo, seldom give rise to new cardiac muscle. In this context, the most important challenge in the field is to fully disclose the molecular and cellular mechanisms that could promote active myocardial regeneration after cardiac damage. Accordingly, we suggest that such strategy should be inspired by the unique regenerative and reparative responses displayed by non-human animal models, from the restricted postnatal myocardial regeneration abilities of the murine heart to the full ventricular regeneration of some bony fishes (e.g., zebrafish). In this review article, we will discuss about current scientific approaches to study cardiac reparative and regenerative phenomena using animal models.

Status, challenges, and future prospects of stem cell therapy in pelvic floor disorders

Pelvic floor disorders (PFDs) represent a group of common and frequently-occurring diseases that seriously affect the life quality of women, generally including stress urinary incontinence and pelvic organ prolapse. Surgery has been used as a treatment for PFD, but almost 30% of patients require subsequent surgery due to a high incidence of postoperative complications and high recurrence rates. Therefore, investigations of new therapeutic strategies are urgently needed. Stem cells possess strong multi-differentiation, self-renewal, immunomodulation, and angiogenesis abilities and they are able to differentiate into various cell types of pelvic floor tissues and thus provide a potential therapeutic approach for PFD. Recently, various studies using different autologous stem cells have achieved promising results by improving the pelvic ligament and muscle regeneration and conferring the tissue elasticity and strength to the damaged tissue in PFD, as well as reduced inflammatory reactions, collagen deposition, and foreign body reaction. However, with relatively high rates of complications such as bladder stone formation and wound infections, further studies are necessary to investigate the role of stem cells as maintainers of tissue homeostasis and modulators in early interventions including therapies using new stem cell sources, exosomes, and tissue-engineering combined with stem cell-based implants, among others. This review describes the types of stem cells and the possible interaction mechanisms in PFD treatment, with the hope of providing more promising stem cell treatment strategies for PFD in the future.

The Expression Profile of Dental Pulp-Derived Stromal Cells Supports Their Limited Capacity to Differentiate into Adipogenic Cells

Mesenchymal stromal cells (MSCs) can self-renew, differentiate into specialised cells and have different embryonic origins-ectodermal for dental pulp-derived MSCs (DPSCs) and mesodermal for adipose tissue-derived MSCs (ADSCs). Data on DPSCs adipogenic differentiation potential and timing vary, and the lack of molecular and genetic information prompted us to gain a better understanding of DPSCs adipogenic differentiation potential and gene expression profile. While DPSCs differentiated readily along osteogenic and chondrogenic pathways, after 21 days in two different types of adipogenic induction media, DPSCs cultures did not contain lipid vacuoles and had low expression levels of the adipogenic genes proliferator-activated receptor gamma (PPARG), lipoprotein lipase (LPL) and CCAAT/enhancer-binding protein alpha (CEBPA). To better understand this limitation in adipogenesis, transcriptome analysis in undifferentiated DPSCs was carried out, with the ADSC transcriptome used as a positive control. In total, 14,871 transcripts were common to DPSCs and ADSCs, some were unique (DPSCs: 471, ADSCs: 1032), and 510 were differentially expressed genes. Detailed analyses of overrepresented transcripts showed that DPSCs express genes that inhibit adipogenic differentiation, revealing the possible mechanism for their limited adipogenesis.

Epidermal neural crest stem cell transplantation as a promising therapeutic strategy for ischemic stroke

Introduction

Cell‐based therapy is considered as promising strategy to cure stroke. However, employing appropriate type of stem cell to fulfill many therapeutic needs of cerebral ischemia is still challenging. In this regard, the current study was designed to elucidate therapeutic potential of epidermal neural crest stem cells (EPI‐NCSCs) compared to bone marrow mesenchymal stem cells (BM‐MSCs) in rat model of ischemic stroke.

Methods

Ischemic stroke was induced by middle cerebral artery occlusion (MCAO) for 45 minutes. Immediately after reperfusion, EPI‐NCSCs or BM‐MSCs were transplanted via intra‐arterial or intravenous route. A test for neurological function was performed before ischemia and 1, 3, and 7 days after MCAO. Also, infarct volume ratio and relative expression of 15 selected target genes were evaluated 7 days after transplantation.

Results

EPI‐NCSCs transplantation (both intra‐arterial and intravenous) and BM‐MSCs transplantation (only intra‐arterial) tended to result in a better functional outcome, compared to the MCAO group; however, this difference was not statistically significant. The infarct volume ratio significantly decreased in NCSC‐intra‐arterial, NCSC‐intravenous and MSC‐intra‐arterial groups compared to the control. EPI‐NCSCs interventions led to higher expression levels of Bdnf, nestin, Sox10, doublecortin, β‐III tubulin, Gfap, and interleukin‐6, whereas neurotrophin‐3 and interleukin‐10 were decreased. On the other hand, BM‐MSCs therapy resulted in upregulation of Gdnf, β‐III tubulin, and Gfap and down‐regulation of neurotrophin‐3, interleukin‐1, and interleukin‐10.

Conclusion

These findings highlight the therapeutic effects of EPI‐NCSCs transplantation, probably through simultaneous induction of neuronal and glial formation, as well as Bdnf over‐expression in a rat model of ischemic stroke.

Autologous Bone Marrow-Derived Stem Cell Therapy for Asherman's Syndrome and Endometrial Atrophy: A 5-Year Follow-up Study

Background:

Based on the role of bone marrow (BM) stem cells in regeneration of endometrium, refractory cases of Asherman's syndrome (AS) and endometrial atrophy (EA) may benefit with BM-derived intrauterine stem cell instillation. Aims and Objectives: To evaluate the role of BM-derived autologous stem cell therapy in endometrial regeneration and restoration of menstruation and fertility in refractory cases of AS and EA.

Setting:

This study was conducted at a tertiary care center.

Design:

This was a prospective, single-arm longitudinal study.

Materials and Methods:

Twenty-five cases with refractory AS or EA were included. BM-derived mononuclear stem cells were instilled into the subendometrial zone followed by oral estrogen therapy for 3 months. Menstrual flow and endometrial thickness (ET) were assessed at 3, 6, and 9 months and 5 years.

Results:

Statistical analysis was carried out using statistical software STATA version 12.0. Mean prestem cell transfer ET (mm) was 3.3 ± 1.0. At the end of 3 months, there was a significant increase in ET (mm) to 5.1 ± 1.9 (P = 0.001), but there was no significant change at 6 months (5.6 ± 1.5; P = 0.164), at 9 months (6.1 ± 1.7; P = 0.135), or at the end of 5 years. Six of the seven amenorrheic patients resumed menses. Three patients had a successful pregnancy outcome.

Conclusion:

Intrauterine stem cell treatment is a promising novel approach for refractory cases of AS and EA.

Mesenchymal stem cell therapy for liver fibrosis/cirrhosis

Liver fibrosis represents a common outcome of most chronic liver diseases. Advanced fibrosis leads to cirrhosis for which no effective treatment is available except liver transplantation. Because of the limitations of liver transplantation, alternative therapeutic strategies are an urgent need to find. Recently, mesenchymal stem cells (MSCs) based therapy has been suggested as an attractive therapeutic option for liver fibrosis and cirrhosis, based on the promising results from preclinical and clinical studies. Although the precise mechanisms of MSC transplantation are still not fully understood, accumulating evidence has indicated that MSCs eliminate the progression of fibrosis due to their immune-modulatory properties. In this review, we summarise the properties of MSCs and their clinical application in the treatment of liver fibrosis and cirrhosis. We also discuss the mechanisms involved in MSC-dependent regulation of immune microenvironment in the context of liver fibrosis and cirrhosis.

Reversing Acute Kidney Injury Using Pulsed Focused Ultrasound and MSC Therapy: A Role for HSP-Mediated PI3K/AKT Signaling

Acute kidney injury (AKI) is characterized by a sudden failure of renal function, but despite increasing worldwide prevalence, current treatments are largely supportive, with no curative therapies. Mesenchymal stromal cell (MSC) therapy has been shown to have a promising regenerative effect in AKI but is limited by the ability of cells to home to damaged tissue. Pulsed focused ultrasound (pFUS), wherein target tissues are sonicated by short bursts of sound waves, has been reported to enhance MSC homing by upregulating local homing signals. However, the exact mechanism by which pFUS enhances MSC therapy remains insufficiently explored. In this study, we studied the effect of bone marrow-derived MSCs (BM-MSCs), in conjunction with pFUS, in a mouse model of cisplatin-induced AKI. Here, BM-MSCs improved kidney function, reduced histological markers of kidney injury, decreased inflammation and apoptosis, and promoted cellular proliferation. Surprisingly, whereas pFUS did not upregulate local cytokine expression or improve BM-MSC homing, it did potentiate the effect of MSC treatment in AKI. Further analysis linked this effect to the upregulation of heat shock protein (HSP)20/HSP40 and subsequent phosphatidylinositol 3-kinase (PI3K)/Akt signaling. In summary, our results suggest that pFUS and BM-MSCs have independent as well as synergistic therapeutic effects in the context of AKI.

Effect of the deuterium on efficiency and type of adipogenic differentiation of human adipose-derived stem cells in vitro

In this study, we performed an adipogenic differentiation of human adipose-derived stem cells (ADSCs) in vitro with different deuterium content (natural, low and high) in the culture medium during differentiation process with parallel analysis of the gene expression, metabolic activity and cell viability/toxicity. After ADSCs differentiation into adipocytes we have done the analysis of differentiation process efficiency and determined a type of resulting adipocytes (by morphology, gene expression, UCP1 protein detection and adipokine production analysis). We have found that high (5 × 10⁵ ppm) deuterium content significantly inhibit in vitro adipogenic differentiation of human ADSCs compared to the groups with natural (150 ppm) and low (30 ppm) deuterium content. Importantly, protocol of differentiation used in our study leads to white adipocytes development in groups with natural (control) and high deuterium content, whereas deuterium-depleted differentiation medium leads to brown-like (beige) adipocytes formation. We have also remarked the direct impact of deuterium on the cellular survival and metabolic activity. Interesting, in deuterium depleted-medium, the cells had normal survival rate and high metabolic activity, whereas the inhibitory effect of deuterated medium on ADSCs differentiation at least was partly associated with deuterium cytotoxicity and inhibitory effect on metabolic activity. The inhibitory effect of deuterium on metabolic activity and the subsequent decrease in the effectiveness of adipogenic differentiation is probably associated with mitochondrial dysfunction. Thus, deuterium could be considered as an element that affects the substance chirality. These findings may be the basis for the development of new approaches in the treatment of obesity, metabolic syndrome and diabetes through the regulation of adipose-derived stem cell differentiation and adipocyte functions.

Mesenchymal stem cells combined with albendazole as a novel therapeutic approach for experimental neurotoxocariasis

Neurotoxocariasis (NT) is a serious condition that has been linked to reduced cognitive function, behavioural alterations and neurodegenerative diseases. Unfortunately, the available drugs to treat toxocariasis are limited with unsatisfactory results, because of the initiation of treatment at late chronic stages after the occurrence of tissue damage and scars. Therefore, searching for a new therapy for this important disease is an urgent necessity. In this context, cytotherapy is a novel therapeutic approach for the treatment of many diseases and tissue damages through the introduction of new cells into the damaged sites. They exert therapeutic effects by their capability of renewal, differentiation into specialized cells, and being powerful immunomodulators. The most popular cell type utilized in cytotherapy is the mesenchymal stem cells (MSCs) type. In the current study, the efficacy of MSCs alone or combined with albendazole was evaluated against chronic brain insults induced by Toxocara canis infection in an experimental mouse model. Interestingly, MSCs combined with albendazole demonstrated a healing effect on brain inflammation, gliosis, apoptosis and significantly reduced brain damage biomarkers (S100B and GFAP) and T. canis DNA. Thus, MSCs would be protective against the development of subsequent neurodegenerative diseases with chronic NT.

The role of ultrasound in enhancing mesenchymal stromal cell-based therapies

Mesenchymal stromal cells (MSCs) have been a popular platform for cell‐based therapy in regenerative medicine due to their propensity to home to damaged tissue and act as a repository of regenerative molecules that can promote tissue repair and exert immunomodulatory effects. Accordingly, a great deal of research has gone into optimizing MSC homing and increasing their secretion of therapeutic molecules. A variety of methods have been used to these ends, but one emerging technique gaining significant interest is the use of ultrasound. Sound waves exert mechanical pressure on cells, activating mechano‐transduction pathways and altering gene expression. Ultrasound has been applied both to cultured MSCs to modulate self‐renewal and differentiation, and to tissues‐of‐interest to make them a more attractive target for MSC homing. Here, we review the various applications of ultrasound to MSC‐based therapies, including low‐intensity pulsed ultrasound, pulsed focused ultrasound, and extracorporeal shockwave therapy, as well as the use of adjunctive therapies such as microbubbles. At a molecular level, it seems that ultrasound transiently generates a local gradient of cytokines, growth factors, and adhesion molecules that facilitate MSC homing. However, the molecular mechanisms underlying these methods are far from fully elucidated and may differ depending on the ultrasound parameters. We thus put forth minimal criteria for ultrasound parameter reporting, in order to ensure reproducibility of studies in the field. A deeper understanding of these mechanisms will enhance our ability to optimize this promising therapy to assist MSC‐based approaches in regenerative medicine.

Comparative Analysis of the Different Dyes' Potential to Assess Human Normal and Cancer Cell Viability In Vitro under Different D/H Ratios in a Culture Medium

In this study, using new approach (laser diffraction + biological dyes), we have demonstrated the decrease of cells viability in vitro in the deuterated growth medium, whereas in the deuterium-depleted medium, there was an increase of cell viability. We have also found that not all dyes are equally sensitive to the D/H ratios in the culture medium (system) as well as to the different cell types (cancer vs normal cells).

Metabolic Coordination of Pericyte Phenotypes: Therapeutic Implications

Pericytes are mural vascular cells found predominantly on the abluminal wall of capillaries, where they contribute to the maintenance of capillary structural integrity and vascular permeability. Generally quiescent cells in the adult, pericyte activation and proliferation occur during both physiological and pathological vascular and tissue remodeling. A considerable body of research indicates that pericytes possess attributes of a multipotent adult stem cell, as they are capable of self-renewal as well as commitment and differentiation into multiple lineages. However, pericytes also display phenotypic heterogeneity and recent studies indicate that lineage potential differs between pericyte subpopulations. While numerous microenvironmental cues and cell signaling pathways are known to regulate pericyte functions, the roles that metabolic pathways play in pericyte quiescence, self-renewal or differentiation have been given limited consideration to date. This review will summarize existing data regarding pericyte metabolism and will discuss the coupling of signal pathways to shifts in metabolic pathway preferences that ultimately regulate pericyte quiescence, self-renewal and trans-differentiation. The association between dysregulated metabolic processes and development of pericyte pathologies will be highlighted. Despite ongoing debate regarding pericyte classification and their functional capacity for trans-differentiation in vivo, pericytes are increasingly exploited as a cell therapy tool to promote tissue healing and regeneration. Ultimately, the efficacy of therapeutic approaches hinges on the capacity to effectively control/optimize the fate of the implanted pericytes. Thus, we will identify knowledge gaps that need to be addressed to more effectively harness the opportunity for therapeutic manipulation of pericytes to control pathological outcomes in tissue remodeling.

Targeting Purinergic Signaling and Cell Therapy in Cardiovascular and Neurodegenerative Diseases

Extracellular purines exert several functions in physiological and pathophysiological mechanisms. ATP acts through P2 receptors as a neurotransmitter and neuromodulator and modulates heart contractility, while adenosine participates in neurotransmission, blood pressure, and many other mechanisms. Because of their capability to differentiate into mature cell types, they provide a unique therapeutic strategy for regenerating damaged tissue, such as in cardiovascular and neurodegenerative diseases. Purinergic signaling is pivotal for controlling stem cell differentiation and phenotype determination. Proliferation, differentiation, and apoptosis of stem cells of various origins are regulated by purinergic receptors. In this chapter, we selected neurodegenerative and cardiovascular diseases with clinical trials using cell therapy and purinergic receptor targeting. We discuss these approaches as therapeutic alternatives to neurodegenerative and cardiovascular diseases. For instance, promising results were demonstrated in the utilization of mesenchymal stem cells and bone marrow mononuclear cells in vascular regeneration. Regarding neurodegenerative diseases, in general, P2X7 and A_2A receptors mostly worsen the degenerative state. Stem cell-based therapy, mainly through mesenchymal and hematopoietic stem cells, showed promising results in improving symptoms caused by neurodegeneration. We propose that purinergic receptor activity regulation combined with stem cells could enhance proliferative and differentiation rates as well as cell engraftment.

Cell therapy with intravascular administration of mesenchymal stromal cells continues to appear safe: An updated systematic review and meta-analysis

BACKGROUND

Characterization of the mesenchymal stromal cell (MSC) safety profile is important as this novel therapy continues to be evaluated in clinical trials for various inflammatory conditions. Due to an increase in published randomized controlled trials (RCTs) from 2012-2019, we performed an updated systematic review to further characterize the MSC safety profile.

METHODS

MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials and Web of Science (to May 2018) were searched. RCTs that compared intravascular delivery of MSCs to controls in adult populations were included. Pre-specified adverse events were grouped according to: (1) immediate, (2) infection, (3) thrombotic/embolic, and (4) longer-term events (mortality, malignancy). Adverse events were pooled and meta-analyzed by fitting inverse-variance binary random effects models. Primary and secondary clinical efficacy endpoints were summarized descriptively.

FINDINGS

7473 citations were reviewed and 55 studies met inclusion criteria (n = 2696 patients). MSCs as compared to controls were associated with an increased risk of fever (Relative Risk (RR) = 2·48, 95% Confidence Interval (CI) = 1·27-4·86; I2 = 0%), but not non-fever acute infusional toxicity, infection, thrombotic/embolic events, death, or malignancy (RR = 1·16, 0·99, 1·14, 0·78, 0·93; 95% CI = 0·70-1·91, 0·81-1·21, 0·67-1·95, 0·65-0·94, 0·60-1·45; I2 = 0%, 0%, 0%, 0%, 0%). No included trials were ended prematurely due to safety concerns.

INTERPRETATIONS

MSC therapy continues to exhibit a favourable safety profile. Future trials should continue to strengthen study rigor, reporting of MSC characterization, and adverse events.

FUNDING

Stem Cell Network, Ontario Institute for Regenerative Medicine and Ontario Research Fund.

Therapeutic Mesenchymal Stromal Cells for Immunotherapy and for Gene and Drug Delivery

Mesenchymal stromal cells (MSCs) possess several fairly unique properties that, when combined, make them ideally suited for cellular-based immunotherapy and as vehicles for gene and drug delivery for a wide range of diseases and disorders. Key among these are: (1) their relative ease of isolation from a variety of tissues; (2) the ability to be expanded in culture without a loss of functionality, a property that varies to some degree with tissue source; (3) they are relatively immune-inert, perhaps obviating the need for precise donor/recipient matching; (4) they possess potent immunomodulatory functions that can be tailored by so-called licensing in vitro and in vivo; (5) the efficiency with which they can be modified with viral-based vectors; and (6) their almost uncanny ability to selectively home to damaged tissues, tumors, and metastases following systemic administration. In this review, we summarize the latest research in the immunological properties of MSCs, their use as immunomodulatory/anti-inflammatory agents, methods for licensing MSCs to customize their immunological profile, and their use as vehicles for transferring both therapeutic genes in genetic disease and drugs and genes designed to destroy tumor cells.

Endometrial stromal cells exhibit a distinct phenotypic and immunomodulatory profile

BACKGROUND

In Asherman's syndrome (AS), intrauterine scarring and fibrotic adhesions lead to menstrual disorders, pregnancy loss, or infertility. A few clinical trials have piloted cell therapy to overcome AS. Understanding the role of the stromal compartment in endometrial regeneration remains poorly understood. We hypothesize that endometrial stromal cells (eSCs) represent a relevant cell population to establish novel cell-based therapeutics for endometrial disorders. The aim of this study was to characterize eSCs and evaluate their immune-cell interactions.

METHODS

eSCs were isolated from healthy donors, during the proliferative stage of the menstrual cycle. Cells were characterized for expression of mesenchymal stromal cell (MSC) markers and assessed for their tumorigenic potential. eSCs were co-cultured with interferon γ and tumor necrosis factor α, and cell surface expression of their respective receptors and human leukocyte antigen (HLA) I and II determined by flow cytometry. Secreted levels of key immunomodulatory factors were established. eSCs were cultured with activated peripheral blood mononuclear cells, and T cell differentiation and proliferation determined.

RESULTS

eSCs demonstrated an MSC surface phenotype and exhibited multipotency. Expanded eSCs retained chromosomal stability and demonstrated no tumorigenicity. Upon stimulation, eSCs licensed to an anti-inflammatory phenotype with upregulated secretion of immunomodulatory factors. Stimulated eSCs did not express HLA class II. eSCs suppressed the proliferation and activation of CD4+ T cells, with the eSC secretome further downregulating central memory T cells and upregulating effector memory (EM) cells.

CONCLUSIONS

Differential responsiveness to inflammation by eSCs, compared to other MSC sources, demonstrates the need to understand the specific functional effects of individual stromal cell sources. A lack of HLA class II and triggering of EM T cell differentiation strongly links to innate in vivo roles of eSCs in tissue repair and immune tolerance during pregnancy. We conclude that eSCs may be an ideal cell therapy candidate for endometrial disorders.

Enhancing the Efficacy of Stem Cell Therapy with Glycosaminoglycans

Human mesenchymal stem cell (hMSC) therapy offers significant potential for osteochondral regeneration. Such applications require their ex vivo expansion in media frequently supplemented with fibroblast growth factor 2 (FGF2). Particular heparan sulfate (HS) fractions stabilize FGF2-FGF receptor complexes. We show that an FGF2-binding HS variant (HS8) accelerates the expansion of freshly isolated bone marrow hMSCs without compromising their naivety. Importantly, the repair of osteochondral defects in both rats and pigs is improved after treatment with HS8-supplemented hMSCs (MSC^HS8), when assessed histologically, biomechanically, or by MRI. Thus, supplementing hMSC culture media with an HS variant that targets endogenously produced FGF2 allows the elimination of exogenous growth factors that may adversely affect their therapeutic potency.

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An FGF2-binding heparan sulfate (HS8) accelerates the ex vivo expansion of hMSCs

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hMSCs expanded with HS8 maintain stem cell characteristics and potency

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HS8-expanded hMSCs improve osteochondral regeneration in animal models

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HS8 is an effective bio-additive for the scale up of highly potent hMSCs

Therapies for osteoarthritis today and tomorrow: Review

Osteoarthritis is a common human disease with well understood pathophysiology, signs and symptoms, prevalence, risk factors, pain, and suffering with great understanding of personal, economic and social effects around the world. There are no drugs or treatments considered "disease modifying", with symptomatic control aiming to stave off the final solution of total joint replacement. Regenerative medicine and use of mesenchymal stem cells (MSC) promised hope to change that but have so far fallen short. This review focuses on current knowledge and use of MSC in clinic, completed research, and future directions for development of this once so promising biological treatment. Powerful treatment for pain in form of monoclonal antibodies against Nerve Growth Factor (NGF) are getting close to FDA approval in the US. Wnt signaling pathway modulators that decrease inflammation, increase function and potential to regenerate cartilage should be presented to the FDA early next year.