Mesenchymal stem cells: immunobiology and role in immunomodulation and tissue regeneration

Mesenchymal stem cells from adipose tissue prone to lose their stemness associated markers in obesity related stress conditions

Obesity is a health problem characterized by large expansion of adipose tissue. During this expansion, genotoxic stressors can be accumulated and negatively affect the mesenchymal stem cells (MSCs) of adipose tissue. Due to the oxidative stress generated by these genotoxic stressors, senescence phenotype might be observed in adipose tissue MSCs. Senescent MSCs lose their proliferations and differentiation properties and secrete senescence-associated molecules to their niche thus triggering senescence for the rest of the tissue. Accumulation of senescent cells in adipose tissue results in decreased tissue regeneration and functional impairment not only in the close vicinity but also in the other tissues. Here we hypothesized that declined tissue regeneration might be associated with loss of stemness markers in MSCs population. We analyzed the expression of several stemness-associated genes of in vitro cultured MSCs originated from adipose tissue of high-fat diet and normal diet mice models. Since the heterogenous MSCs population covers a small percentage of the pluripotent stem cells, which have roles in proliferation and tissue regeneration, we measured the percentage of these cells via TRA-1-60 pluripotent state antigen. Additionally, by conducting a shotgun proteomic approach using LC-MS/MS, whole cell proteome of the adipose tissue MSCs of high-fat diet and normal diet mice were analyzed and identified proteins were evaluated via gene ontology and PPI network analysis. MSCs of obese mice showed senescent phenotype and altered cell cycle distribution due to a hostile environment with oxidative stress in adipose tissue where they reside. Additionally, the number of pluripotent markers expressing cells declined in the MSC population of the high-fat diet mice. Gene expression analysis evidenced the loss of stemness with a decrease in the expression of stemness-associated genes. Of the proteomic comparison of the normal and the high-fat diet group, MSCs revealed that stemness-associated molecules were decreased while inflammation and senescence-associated phenotypes emerged in obese mice MSCs. Our results showed us that the MSCs of adipose tissue may lose their stemness properties due to obesity-associated stress conditions.

The impact of subdermal adipose derived stem cell injections and early excision on systemic oxidative stress and wound healing in rats with severe scald burns

AIM

This study aims to develop an experimental treatment model effective against oxidative stress in the acute period of severe burns and to analyze the mechanisms of healing large wound defects.

METHODS

Five rats, including 2 females and 3 males, were used as donors to obtain adipose-derived stem cells (ADSC) from the inguinal fat pad. The stem cells were labeled with green fluorescent protein. The study included four groups of 17 rats, each with grade 3 scalding burns on 30 % of their body surface, and a control group of 10 rats with an equal number of males and females. After early excision, 106 ADSC-derived stem cells were administered subdermally to the burned wound and autografted to the stem cell group (n = 17). The early excision group (n = 17) received early excision and autograft, with 2 ml of normal saline injected subdermally into the burn wound edge. The PLM group (n = 17) was treated with a polylactic membrane (PLM) dressing after the burn. No treatment was given to the burn group (n = 17). Ten rats from all groups were sacrificed on the 4th day post-burn for oxidative stress evaluation. The control group (n = 10) was sacrificed on day 4. Blood and tissue samples were collected post-sacrifice. Oxidative stress and inflammation in the blood, as well as cell damage in the skin, liver, kidneys, and lungs, were investigated histopathologically and biochemically on the 4th day post-burn. On the 70th day after burn, wound healing was examined macroscopically and histopathologically.

RESULTS

On the 4th day, oxidative stress results showed that the levels of Total Oxidative Capacity (TOC) in the blood were lowest in the stem cell (7.4 [6-8.8]), control (6.7 [5.9-7.6]), and early excision (7.5 [6.6-8.5]) groups, with no significant difference between them. The burn group (14.7 [12.5-16.9]) had the highest TOC levels. The PLM group (9.7 [8.6-10.7]) had lower TOC levels than the burn group but higher levels than the other groups. Histopathological examination on the 4th day revealed low liver caspase-3 immunoreactivity in the stem cell and early excision groups among the burn groups. Caspase-3 immunoreactivity levels were as follows: stem cell group (20 [10-30]), early excision group (25 [15-50]), PLM group (70 [50-100]), control group (0), and burn group (80 [60-120]). Other oxidative stress and end-organ damage outcomes were consistent with these results. All rats in the stem cell group had burn wounds that healed completely by the 70th day. Examination of the skin and its appendages from the stem cell group with an immunofluorescence microscope demonstrated green coloration, indicating incorporation of stem cells.

CONCLUSION

Stem cells may have the potential to form new skin and its appendages, providing better healing for large skin defects. Early excision treatment, by removing local necrotic tissues after extensive and deep burns, can prevent end-organ damage due to systemic oxidative stress and inflammation. We also believe that when these two treatments are used together, they can achieve the best results.

Controlling redox state by edaravone at transplantation site enhances bone regeneration

In cell-based bone augmentation, transplanted cell dysfunction and apoptosis can occur due to oxidative stress caused by the overproduction of reactive oxygen species (ROS). Edaravone (EDA) is a potent free radical scavenger with potential medical applications. This study aimed to investigate the effect of controlling oxidative stress on bone regeneration using EDA. Bone marrow-derived cells were collected from 4-week-old rats, and EDA effects on cell viability and osteogenic differentiation were evaluated. Collagen gels containing PKH26-prelabeled cells were implanted into the calvarial defects of 12-week-old rats, followed by daily subcutaneous injections of normal saline or 500 μM EDA for 4 d. Bone formation was examined using micro-computed tomography and histological staining. Immunofluorescence staining was performed for markers of oxidative stress, macrophages, osteogenesis, and angiogenesis. EDA suppressed ROS production and hydrogen peroxide-induced apoptosis, recovering cell viability and osteoblast differentiation. EDA treatment in vivo increased new bone formation. EDA induced the transition of the macrophage population toward the M2 phenotype. The EDA group also exhibited stronger immunofluorescence for vascular endothelial growth factor and CD31. In addition, more PKH26-positive and PKH26-osteocalcin-double-positive cells were observed in the EDA group, indicating that transplanted cell survival was prolonged, and they differentiated into bone-forming cells. This could be attributed to oxidative stress suppression at the transplantation site by EDA. Collectively, local administration using EDA facilitates bone regeneration by improving the local environment and angiogenesis, prolonging survival, and enhancing the osteogenic capabilities of transplanted cells.

Recent advances in the adjunctive management of diabetic foot ulcer: Focus on noninvasive technologies

Diabetic foot ulcer (DFU) is one of the most costly and serious complications of diabetes. Treatment of DFU is usually challenging and new approaches are required to improve the therapeutic efficiencies. This review aims to update new and upcoming adjunctive therapies with noninvasive characterization for DFU, focusing on bioactive dressings, bioengineered tissues, mesenchymal stem cell (MSC) based therapy, platelet and cytokine-based therapy, topical oxygen therapy, and some repurposed drugs such as hypoglycemic agents, blood pressure medications, phenytoin, vitamins, and magnesium. Although the mentioned therapies may contribute to the improvement of DFU to a certain extent, most of the evidence come from clinical trials with small sample size and inconsistent selections of DFU patients. Further studies with high design quality and adequate sample sizes are necessitated. In addition, no single approach would completely correct the complex pathogenesis of DFU. Reasonable selection and combination of these techniques should be considered.

Bone Marrow Nucleated Cells and Bone Marrow-Derived CD271+ Mesenchymal Stem Cell in Treatment of Encephalopathy and Drug-Resistant Epilepsy

The broad spectrum of brain injuries in preterm newborns and the plasticity of the central nervous system prompts us to seek solutions for neurodegeneration to prevent the consequences of prematurity and perinatal problems. The study aimed to evaluate the safety and efficacy of the implantation of autologous bone marrow nucleated cells and bone marrow mesenchymal stem cells in different schemes in patients with hypoxic-ischemic encephalopathy and immunological encephalopathy. Fourteen patients received single implantation of bone marrow nucleated cells administered intrathecally and intravenously, followed by multiple rounds of bone marrow mesenchymal stem cells implanted intrathecally, and five patients were treated only with repeated rounds of bone marrow mesenchymal stem cells. Seizure outcomes improved in most cases, including fewer seizures and status epilepticus and reduced doses of antiepileptic drugs compared to the period before treatment. The neuropsychological improvement was more frequent in patients with hypoxic-ischemic encephalopathy than in the immunological encephalopathy group. Changes in emotional functioning occurred with similar frequency in both groups of patients. In the hypoxic-ischemic encephalopathy group, motor improvement was observed in all patients and the majority in the immunological encephalopathy group. The treatment had manageable toxicity, mainly mild to moderate early-onset adverse events. The treatment was generally safe in the 4-year follow-up period, and the effects of the therapy were maintained after its termination.

Mesenchymal Stem Cells Regulate Microglial Polarization via Inhibition of the HMGB1/TLR4 Signaling Pathway in Diabetic Retinopathy

Diabetic retinopathy (DR) is recognized as the most prevalent retinal degenerative disorder. Inflammatory response usually precedes microvascular alteration and is the primary factor of diabetic retinopathy. Activated microglia express many pro-inflammatory cytokines that exacerbate retina inflammation and disruption. In the present study, we found that MSCs alleviated blood-retina barrier (BRB) breakdown in diabetic rats, as evidenced by reduced retinal edema, decreased vascular leakage, and increased occludin expression. The MSC-treated retinal microglia exhibited reduced expression of M1-phenotype markers in the diabetic rats, including inducible nitric oxide synthase (iNOS), CD16, and pro-inflammatory cytokines. On the other hand, MSCs increased the expression of M2-phenotype markers, such as arginase-1 (Arg-1), CD206, and anti-inflammatory cytokines. HMGB1/TLR4 signaling pathway is activated in DR and inhibited after MSC treatment. Consistent with in vivo evidence, MSCs drove BV2 microglia toward M2 phenotype in vitro. Overexpression of HMGB1 in microglia reversed the effects of MSC treatment, suggesting HMGB1/TLR4 pathway is necessary for MSCs' regulatory effects on microglia polarization. Collectively, MSCs exert beneficial effects on DR by polarizing microglia from M1 toward M2 phenotype via inhibiting the HMGB1/TLR4 signaling pathway.

Immunomodulatory-associated gene transcripts to multipotency of bovine amniotic fluid mesenchymal stem cells

The adnexa fetal tissues are sources of mesenchymal stromal cells (MSCs) due to their noninvasive harvest, with all biological material discarded most of the time. MSCs are a promise regarding to their plasticity, self-renewal, differentiation potentials, immunomodulatory and anti-inflammatory properties, which have made clinical stem cell therapy a reality. The present study aimed to characterize and evaluate the immunomodulation ability of bovine mesenchymal cells collected from bovine amniotic fluid (bAFMSCs) isolated and subjected to sixth consecutive culture passages in vitro. The multilineage properties of the bAFMSCs collections confirmed the ability to undergo adipogenic, chondrogenic and osteogenic differentiation. The mesenchymal gene transcription CD106, CD73, CD29, CD90 and CD166 were detected in bAFMSCs, whereas CD34 and CD45 were not detected. Regarding cytokine mRNA expression, IL2, IL6, INFα, INFβ, INFγ, TNFα and TNFβ were downregulated, while IL10 was highly regulated in all studied passages. The present study demonstrated the immunological properties and multipotency of in vitro bAFMSCs collections, and thus, they can be tested in cattle pathological treatments or multiplication by nuclear transfer cloning.

Extracellular vesicles are key players in mesenchymal stem cells' dual potential to regenerate and modulate the immune system

MSCs are used for treatment of inflammatory conditions or for regenerative purposes. MSCs are complete cells and allogenic transplantation is in principle possible, but mostly autologous use is preferred. In recent years, it was discovered that cells secrete extracellular vesicles. These are active budded off vesicles that carry a cargo. The cargo can be miRNA, protein, lipids etc. The extracellular vesicles can be transported through the body and fuse with target cells. Thereby, they influence the phenotype and modulate the disease. The extracellular vesicles have, like the MSCs, immunomodulatory or regenerative capacities. This review will focus on those features of extracellular vesicles and discuss their dual role. Besides the immunomodulation, the regeneration will concentrate on bone, cartilage, tendon, vessels and nerves. Current clinical trials with extracellular vesicles for immunomodulation and regeneration that started in the last five years are highlighted as well. In summary, extracellular vesicles have a great potential as disease modulating entity and treatment. Their dual characteristics need to be taken into account and often are both important for having the best effect.

Associating growth factor secretions and transcriptomes of single cells in nanovials using SEC-seq

Cells secrete numerous bioactive molecules that are essential for the function of healthy organisms. However, scalable methods are needed to link individual cell secretions to their transcriptional state over time. Here, by developing and using secretion-encoded single-cell sequencing (SEC-seq), which exploits hydrogel particles with subnanolitre cavities (nanovials) to capture individual cells and their secretions, we simultaneously measured the secretion of vascular endothelial growth factor A (VEGF-A) and the transcriptome for thousands of individual mesenchymal stromal cells. Our data indicate that VEGF-A secretion is heterogeneous across the cell population and is poorly correlated with the VEGFA transcript level. The highest VEGF-A secretion occurs in a subpopulation of mesenchymal stromal cells characterized by a unique gene expression signature comprising a surface marker, interleukin-13 receptor subunit alpha 2 (IL13RA2), which allowed the enrichment of this subpopulation. SEC-seq enables the identification of gene signatures linked to specific secretory states, facilitating mechanistic studies, the isolation of secretory subpopulations and the development of means to modulate cellular secretion.

Wireless Electric Cues Mediate Autologous DPSC-Loaded Conductive Hydrogel Microspheres to Engineer the Immuno-Angiogenic Niche for Homologous Maxillofacial Bone Regeneration

Stem cell therapy serves as an effective treatment for bone regeneration. Nevertheless, stem cells from bone marrow and peripheral blood are still lacking homologous properties. Dental pulp stem cells (DPSCs) are derived from neural crest, in coincidence with maxillofacial tissues, thus attracting great interest in in situ maxillofacial regenerative medicine. However, insufficient number and heterogenous alteration of seed cells retard further exploration of DPSC-based tissue engineering. Electric stimulation has recently attracted great interest in tissue regeneration. In this study, a novel DPSC-loaded conductive hydrogel microspheres integrated with wireless electric generator is fabricated. Application of exogenous electric cues can promote stemness maintaining and heterogeneity suppression for unpredictable differentiation of encapsulated DPSCs. Further investigations observe that electric signal fine-tunes regenerative niche by improvement on DPSC-mediated paracrine pattern, evidenced by enhanced angiogenic behavior and upregulated anti-inflammatory macrophage polarization. By wireless electric stimulation on implanted conductive hydrogel microspheres, loaded DPSCs facilitates the construction of immuno-angiogenic niche at early stage of tissue repair, and further contributes to advanced autologous mandibular bone defect regeneration. This novel strategy of DPSC-based tissue engineering exhibits promising translational and therapeutic potential for autologous maxillofacial tissue regeneration.

Immunomodulation by mesenchymal stem cells during osteogenic differentiation: Clinical implications during bone regeneration

Critical bone defects resulting in delayed and non-union are a major concern in the field of orthopedics. Over the past decade, mesenchymal stem cells (MSCs) have become a promising frontier for bone repair and regeneration owing to their high expansion rate and osteogenic differentiation potential ex vivo. MSCs have also long been associated with their ability to modulate immune response in the recipients. These can even skew the immune response towards pro-inflammatory or anti-inflammatory type by sensing their local microenvironment. MSCs adopt anti-inflammatory phenotype at bone injury site and secrete various immunomodulatory factors such as IDO, NO, TGFβ1 and PGE-2 which have redundant role in osteoblast differentiation and bone formation. As such, several studies have also sought to decipher the immunomodulatory effects of osteogenically differentiated MSCs. The present review discusses the immunomodulatory status of MSCs during their osteogenic differentiation and summarizes few mechanisms that cause immunosuppression by osteogenically differentiated MSCs and its implication during bone healing.

Effect of hypoxia on the expression of microRNA in extracellular vesicles of human umbilical cord stem cells in vitro

Mesenchymal stem cells (MSCs) derived extracellular vesicles, which have been shown to possess therapeutic effects for many diseases. However, how hypoxic conditions would affect exosomal microRNA expression in human umbilical cord MSCs (hUC-MSCs) is currently not investigated. This study aims to investigate the potential function of in vitro microRNAs of hUC-MSC cultured under normoxic and hypoxic conditions. Extracellular vesicles secreted from hUC-MSCs cultured in normoxic (21% O2) and hypoxic (5% O2) conditions were collected for microRNA identification. Zeta View Laser Scattering and transmission electron microscopy were used to observe the size and morphology of extracellular vesicles. qRT-PCR was performed to measure the expression of related microRNAs. The Gene Ontology and KEGG pathway were used to predict the function of microRNAs. Finally, the effects of hypoxia on the expression of related mRNAs and cellular activity were examined. This study identified 35 upregulated and 8 downregulated microRNAs in the hypoxia group. We performed target genes analysis to explore the potential function of these microRNA upregulated in the hypoxia group. Significant enrichment of the cell proliferation, pluripotency of stem cells, MAPK, Wnt, and adherens junction pathways were observed in the GO and KEGG pathways. Under hypoxic conditions, the expression levels of 7 target genes were lower than that of the normal environment. In conclusion, this study demonstrated for the first time that microRNA expression in extracellular vesicles of human umbilical vein stem cells cultured under hypoxia is different from that under normal conditions, and these microRNAs may be markers for detecting hypoxia.

Allogeneic Mesenchymal Stem Cells After In Vivo Transplantation: A Review

Autologous mesenchymal stem cells (MSCs) are ideal for tissue regeneration because of their ability to circumvent host rejection, but their procurement and processing present logistical and time-sensitive challenges. Allogeneic MSCs provide an alternative cell-based therapy capable of positively affecting all human organ systems, and can be readily available. Extensive research has been conducted in the treatment of autoimmune, degenerative, and inflammatory diseases with such stem cells, and has demonstrated predominantly safe outcomes with minimal complications. Nevertheless, continued clinical trials are necessary to ascertain optimal harvest and transplant techniques.

Microencapsulated stem cells reduce cartilage damage in a material dependent manner following minimally invasive intra-articular injection in an OA rat model

Osteoarthritis (OA) is a degenerative disease of the joints for which no curative treatment exists. Intra-articular injection of stem cells is explored as a regenerative approach, but rapid clearance of cells from the injection site limits the therapeutic outcome. Microencapsulation of mesenchymal stem cells (MSCs) can extend the retention time of MSCs, but the outcomes of the few studies currently performed are conflicting. We hypothesize that the composition of the micromaterial's shell plays a deciding factor in the treatment outcome of intra-articular MSC injection. To this end, we microencapsulate MSCs using droplet microfluidic generators in flow-focus mode using various polymers and polymer concentrations. We demonstrate that polymer composition and concentration potently alter the metabolic activity as well as the secretome of MSCs. Moreover, while microencapsulation consistently prolongs the retention time of MSC injected in rat joints, distinct biodistribution within the joint is demonstrated for the various microgel formulations. Furthermore, intra-articular injections of pristine and microencapsulated MSC in OA rat joints show a strong material-dependent effect on the reduction of cartilage degradation and matrix loss. Collectively, this study highlights that micromaterial composition and concentration are key deciding factors for the therapeutic outcome of intra-articular injections of microencapsulated stem cells to treat degenerative joint diseases.

Mesenchymal stem cells (MSCs) and MSC-derived exosomes in animal models of central nervous system diseases: Targeting the NLRP3 inflammasome

The NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3) inflammasome is a multimeric protein complex that is engaged in the innate immune system and plays a vital role in inflammatory reactions. Activation of the NLRP3 inflammasome and subsequent release of proinflammatory cytokines can be triggered by microbial infection or cellular injury. The NLRP3 inflammasome has been implicated in the pathogenesis of many disorders affecting the central nervous system (CNS), ranging from stroke, traumatic brain injury, and spinal cord injury to Alzheimer's disease, Parkinson's disease, epilepsy, multiple sclerosis, and depression. Furthermore, emerging evidence has suggested that mesenchymal stem cells (MSCs) and their exosomes may modulate NLRP3 inflammasome activation in a way that might be promising for the therapeutic management of CNS diseases. In the present review, particular focus is placed on highlighting and discussing recent scientific evidence regarding the regulatory effects of MSC-based therapies on the NLRP3 inflammasome activation and their potential to counteract proinflammatory responses and pyroptotic cell death in the CNS, thereby achieving neuroprotective impacts and improvement in behavioral impairments.

SOCS3 Protein Mediates the Therapeutic Efficacy of Mesenchymal Stem Cells against Acute Lung Injury

Mesenchymal stem cells (MSCs) have been studied as novel therapeutic agents because of their immunomodulatory properties in inflammatory diseases. The suppressor of cytokine signaling (SOCS) proteins are key regulators of the immune response and macrophage modulation. In the present study, we hypothesized that SOCS in MCSs might mediate macrophage modulation and tested this in a bacteria-induced acute lung injury (ALI) mouse model. The macrophage phenotype was observed in RAW264.7 alveolar macrophages exposed to lipopolysaccharide (LPS) in an in vitro model, and in the ALI mouse model induced by tracheal administration of Escherichia coli (1 × 10⁷ CFU in 0.05mL PBS). In LPS-exposed RAW264.7 cells, the levels of markers of M1 macrophages, such as CD86 and pro-inflammatory cytokines (IL-1α, IL-1β, IL-6 and TNF-α), significantly increased, but they significantly reduced after MSC treatment. Meanwhile, the levels of markers of M2 macrophages, such as CD204 and anti-inflammatory cytokines (IL-4 and IL-10), increased after LPS exposure, and further significantly increased after MSC treatment. This regulatory effect of MSCs on M1/M2 macrophage polarization was significantly abolished by SOCS3 inhibition. In the E. coli-induced ALI model, tissue injury and inflammation in the mouse lung were significantly attenuated by the transplantation of MSCs, but not by SOCS3-inhibited MSCs. The regulatory effect of MSCs on M1/M2 macrophage polarization was observed in the lung injury model but was significantly abolished by SOCS3 inhibition. Taken together, our findings suggest that SOCS3 is an important mediator for macrophage modulation in anti-inflammatory properties of MSCs.

Strategies for organ preservation: Current prospective and challenges

In current therapeutic approaches, transplantation of organs provides the best available treatment for a myriad of end-stage organ failures. However, shortage of organ donors, lacunae in preservation methods, and lack of a suitable match are the major constraints in advocating this life-sustaining therapy. There has been continuous progress in the strategies for organ preservation since its inception. Current strategies for organ preservation are based on the University of Wisconsin (UW) solution using the machine perfusion technique, which allows successful preservation of intra-abdominal organs (kidney and liver) but not intra-thoracic organs (lungs and heart). However, novel concepts with a wide range of adapted preservation technologies that can increase the shelf life of retrieved organs are still under investigation. The therapeutic interventions of in vitro-cultured stem cells could provide novel strategies for replacement of nonfunctional cells of damaged organs with that of functional ones. This review describes existing strategies, highlights recent advances, discusses challenges and innovative approaches for effective organ preservation, and describes application of stem cells to restore the functional activity of damaged organs for future clinical practices.

Secretion encoded single-cell sequencing (SEC-seq) uncovers gene expression signatures associated with high VEGF-A secretion in mesenchymal stromal cells

Cells secrete numerous bioactive molecules essential for the function of healthy organisms. However, there are no scalable methods to link individual cell secretions to their transcriptional state. By developing and using secretion encoded single-cell sequencing (SEC-seq), which exploits hydrogel nanovials to capture individual cells and their secretions, we simultaneously measured the secretion of vascular endothelial growth factor A (VEGF-A) and the transcriptome for thousands of individual mesenchymal stromal cells (MSCs). We found that VEGF-A secretion is heterogeneous across the cell population and lowly correlated with the VEGFA transcript level. While there is a modest population-wide increase in VEGF-A secretion by hypoxic induction, highest VEGF-A secretion across normoxic and hypoxic culture conditions occurs in a subpopulation of MSCs characterized by a unique gene expression signature. Taken together, SEC-seq enables the identification of specific genes involved in the control of secretory states, which may be exploited for developing means to modulate cellular secretion for disease treatment.

Combination of immunosuppressive drugs and allogeneic stem cell treatment in a dog with suspected nephrotic syndrome

The case study aims to describe the nephrotic syndrome (NS) in a castrated 3-year-old male Cocker Spaniel dog. The patient arrived at the hospital with a loss of appetite and weakness. Skin oedema with ascites was observed along with hypoalbuminaemia, hypoproteinaemia, hyperlipidaemia, hypercholesterolaemia, and proteinuria (urine protein to creatinine ratio = 22.4). Based on these findings, the patient was diagnosed with NS, although a renal biopsy was not conducted. Prednisolone (1 mg/kg, p.o. q12 h) and mycophenolate mofetil (10 mg/kg, p.o. q12 h) were prescribed as the immunosuppressive drugs, and previously cryopreserved allogeneic adipose tissue-derived mesenchymal stem cells (2 × 107 cells/kg) were injected intravenously. After several weeks of treatment, the patient recovered from NS. This is the first case report on immunosuppressive drugs and allogeneic mesenchymal stem cells being used to treat a dog with NS.

Feasibility and Safety of Low-Dose Mesenchymal Stem Cell Infusion in Lung Transplant Recipients

Background

We have previously shown bone marrow-derived mesenchymal stem cells (MSCs) may shift immune responses toward anti-inflammatory pathways and stabilize the course of obstructive chronic lung allograft syndrome (o-CLAD) after lung transplantation. In this study, we measured the response of lower dose infusions.

Methods

We infused low-dose MSCs intravenously in 13 patients who had developed moderate-to-severe o-CLAD. Three had previously received an infusion of MSCs from a different donor and were re-dosed at 1 × 10⁶ MSC/kg, while 5 received a first dose at 1 × 10⁶ MSC/kg and five received an even lower dose at 0.5 × 10⁶ MSC/kg. We recorded pulmonary function tests before and after infusion, and patients were followed clinically for 12 months.

Results

Infusions were well tolerated, and no significant adverse events were recorded in the first 30 days. There was significant decline (mean ± SD) in forced vital capacity (FVC) (3.49 ± 1.03 vs 3.18 ± 0.94 L, P = .03) and forced expiratory volume in 1 second (FEV1) (2.28 ± 0.86 vs 1.77 ± 0.49 L, P = .04) over the year preceding infusion. FVC (3.18 ± 0.94 vs 3.46 ± 0.99 L, P = .53) and FEV1 was not significantly changed (1.77 ± 0.49 vs 1.88 ± 0.75, P = .72) when comparing values immediately prior to infusion to those obtained 1 year after infusion, indicating a possible stabilizing effect on lung function decline due to o-CLAD.

Conclusion

Intravenous infusions of bone marrow-derived MSCs are well tolerated in lung transplant recipients with moderate-to-severe CLAD. Low-dose MSCs appear to slow progression of CLAD in some patients.

Shear Stress Enhances the Paracrine-Mediated Immunoregulatory Function of Human Periodontal Ligament Stem Cells via the ERK Signalling Pathway

Relevant immunomodulatory effects have been proposed following allogeneic cell-based therapy with human periodontal ligament stem cells (hPDLSCs). This study aimed to examine the influence of shear stress on the immunosuppressive capacity of hPDLSCs. Cells were subjected to shear stress at different magnitudes (0.5, 5 and 10 dyn/cm2). The expression of immunosuppressive markers was evaluated in shear stress-induced hPDLSCs using qRT-PCR, western blot, enzyme activity and enzyme-linked immunosorbent assays. The effects of a shear stress-derived condition medium (SS-CM) on T cell proliferation were examined using a resazurin assay. Treg differentiation was investigated using qRT-PCR and flow cytometry analysis. Our results revealed that shear stress increased mRNA expression of IDO and COX2 but not TGF-β1 and IFN-γ. IDO activity, kynurenine and active TGF-β1 increased in SS-CM when compared to the non-shear stress-derived conditioned medium (CTL-CM). The amount of kynurenine in SS-CM was reduced in the presence of cycloheximide and ERK inhibitor. Subsequently, T cell proliferation decreased in SS-CM compared to CTL-CM. Treg differentiation was promoted in SS-CM, indicated by FOXP3, IL-10 expression and CD4+CD25hiCD127lo/− subpopulation. In conclusion, shear stress promotes kynurenine production through ERK signalling in hPDLSC, leading to the inhibition of T cell proliferation and the promotion of Treg cell differentiation.

Mesenchymal Stem Cell Application and Its Therapeutic Mechanisms in Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH), a common lethal subtype of stroke accounting for nearly 10–15% of the total stroke disease and affecting two million people worldwide, has a high mortality and disability rate and, thus, a major socioeconomic burden. However, there is no effective treatment available currently. The role of mesenchymal stem cells (MSCs) in regenerative medicine is well known owing to the simplicity of acquisition from various sources, low immunogenicity, adaptation to the autogenic and allogeneic systems, immunomodulation, self-recovery by secreting extracellular vesicles (EVs), regenerative repair, and antioxidative stress. MSC therapy provides an increasingly attractive therapeutic approach for ICH. Recently, the functions of MSCs such as neuroprotection, anti-inflammation, and improvement in synaptic plasticity have been widely researched in human and rodent models of ICH. MSC transplantation has been proven to improve ICH-induced injury, including the damage of nerve cells and oligodendrocytes, the activation of microglia and astrocytes, and the destruction of blood vessels. The improvement and recovery of neurological functions in rodent ICH models were demonstrated via the mechanisms such as neurogenesis, angiogenesis, anti-inflammation, anti-apoptosis, and synaptic plasticity. Here, we discuss the pathological mechanisms following ICH and the therapeutic mechanisms of MSC-based therapy to unravel new cues for future therapeutic strategies. Furthermore, some potential strategies for enhancing the therapeutic function of MSC transplantation have also been suggested.

CT/bioluminescence dual-modal imaging tracking of stem cells labeled with Au@PEI@PEG nanotracers and RfLuc in nintedanib-assisted pulmonary fibrosis therapy

Mesenchymal stem cells (MSCs) are promising in idiopathic pulmonary fibrosis (IPF) therapy. However, low survival rate and ambiguous behavior of MSCs after transplantation impede their clinical translation. To this end, we have developed a new strategy to improve the survival rate and monitor the behavior of the transplanted MSCs simultaneously. In our strategy, nintedanib, a tyrosine kinase inhibitor, is employed to protect the human MSCs (hMSCs) from excessive oxidative stress responses and inflammatory environment in the damaged lung. Moreover, by labeling of the transplanted hMSCs with a computed tomography (CT) nanotracer, Au nanoparticles functionalized with polyethylenimine (PEI) and polyethylene glycol (PEG) (Au@PEI@PEG), in combination with red-emitting firefly luciferase (RfLuc), in vivo CT/bioluminescence (BL) dual-modal imaging tracking of the location, distribution, and survival of the transplanted hMSCs in presence of nintedanib were achieved, which facilitates the profound understanding of the role the stem cells play in IPF therapy.

Multipotent Stromal Cells and Viral Interaction: Current Implications for Therapy

Multipotent stromal cells (MSCs) are widely utilized in therapy for their immunomodulatory properties, but their usage in infectious viral diseases is less explored. This review aimed to collate the current novel use of MSCs in virus-associated conditions, including MSC's susceptibility to virus infection, antiviral properties of MSCs and their effects on cell-based immune response and implementation of MSC therapy in animal models and human clinical trials of viral diseases. Recent discoveries shed lights on MSC's capability in suppressing viral replication and augmenting clearance through enhancement of antiviral immunity. MSC therapy may maintain a crucial balance between aiding pathogen clearance and suppressing hyperactive immune response.

Constructing a cell microenvironment with biomaterial scaffolds for stem cell therapy

Stem cell therapy is widely recognized as a promising strategy for exerting therapeutic effects after injury in degenerative diseases. However, limitations such as low cell retention and survival rates after transplantation exist in clinical applications. In recent years, emerging biomaterials that provide a supportable cellular microenvironment for transplanted cells have optimized the therapeutic efficacy of stem cells in injured tissues or organs. Advances in the engineered microenvironment are revolutionizing our understanding of stem cell-based therapies by co-transplanting with synthetic and tissue-derived biomaterials, which offer a scaffold for stem cells and propose an unprecedented opportunity to further employ significant influences in tissue repair and regeneration.

Stem Cell Therapy for Burns: Story so Far

Burn injuries affect approximately 11 million people annually, with fatalities amounting up to 180,000. Burn injuries constitute a global health issue associated with high morbidity and mortality. Recent years have seen advancements in regenerative medicine for burn wound healing encompassing stem cells and stem cell-derived products such as exosomes and conditioned media with promising results compared to current treatment approaches. Sources of stem cells used for treatment vary ranging from hair follicle stem cells, embryonic stem cells, umbilical cord stem cells, to mesenchymal stem cells, such as adipose-derived mesenchymal stem cells, bone marrow-derived mesenchymal stem cells, and even stem cells harvested from discarded burn tissue. Stem cells utilize various pathways for wound healing, such as PI3/AKT pathway, WNT-β catenin pathway, TGF-β pathway, Notch and Hedgehog signaling pathway. Due to the paracrine signaling mechanism of stem cells, exosomes and conditioned media derived from stem cells have also been utilized in burn wound therapy. As exosomes and conditioned media are cell-free therapy and contain various biomolecules that facilitate wound healing, they are gaining popularity as an alternative treatment strategy with significant improvement in outcomes. The treatment is provided either as direct injections or embedded in a natural/artificial scaffold. This paper reviews in detail the different sources of stem cells, stem cell-derived products, their efficacy in burn wound repair, associated signaling pathways and modes of delivery for wound healing.

Endometrial SUSD2+ Mesenchymal Stem/Stromal Cells in Tissue Engineering: Advances in Novel Cellular Constructs for Pelvic Organ Prolapse

Cellular therapy is an emerging field in clinical and personalised medicine. Many adult mesenchymal stem/progenitor cells (MSC) or pluripotent derivatives are being assessed simultaneously in preclinical trials for their potential treatment applications in chronic and degenerative human diseases. Endometrial mesenchymal stem/progenitor cells (eMSC) have been identified as clonogenic cells that exist in unique perivascular niches within the uterine endometrium. Compared with MSC isolated from other tissue sources, such as bone marrow and adipose tissue, eMSC can be extracted through less invasive methods of tissue sampling, and they exhibit improvements in potency, proliferative capacity, and control of culture-induced differentiation. In this review, we summarize the potential cell therapy and tissue engineering applications of eMSC in pelvic organ prolapse (POP), emphasising their ability to exert angiogenic and strong immunomodulatory responses that improve tissue integration of novel surgical constructs for POP and promote vaginal tissue healing.

Toward a Better Regeneration through Implant-Mediated Immunomodulation: Harnessing the Immune Responses

Tissue repair/regeneration, after implantation or injury, involves comprehensive physiological processes wherein immune responses play a crucial role to enable tissue restoration, amidst the immune cells early-stage response to tissue damages. These cells break down extracellular matrix, clear debris, and secret cytokines to orchestrate regeneration. However, the immune response can also lead to abnormal tissue healing or scar formation if not well directed. This review first introduces the general immune response post injury, with focus on the major immune cells including neutrophils, macrophages, and T cells. Next, a variety of implant-mediated immunomodulation strategies to regulate immune response through physical, chemical, and biological cues are discussed. At last, various scaffold-facilitated regenerations of different tissue types, such as, bone, cartilage, blood vessel, and nerve system, by harnessing the immunomodulation are presented. Therefore, the most recent data in biomaterials and immunomodulation is presented here in a bid to shape expert perspectives, inspire researchers to go in new directions, and drive development of future strategies focusing on targeted, sequential, and dynamic immunomodulation elicited by implants.

Bone marrow/bone pre-metastatic niche for breast cancer cells colonization: The role of mesenchymal stromal cells

Breast cancer is one of the most common oncological pathologies in women worldwide. While its early diagnosis has considerably improved, about 70 % of advanced patients develop bone metastases with a high mortality rate. Several authors demonstrated that primary breast cancer cells prepare their future metastatic niche -known as the pre-metastatic niche- to turn it into an "optimal soil" for colonization. The role of the different cellular components of the bone marrow/bone niche in bone metastasis has been well described. However, studying the changes that occur in this microenvironment before tumor cells arrival has become a novel research field. Therefore, the purpose of this review is to describe the current knowledge about the modulation of the normal bone marrow/bone niche by the primary breast tumor, in particular, highlighting the role of mesenchymal stem/stromal cells in transforming this soil into a pre-metastatic niche for breast cancer cells colonization.

Cell therapies in the clinic

Cell therapies have emerged as a promising therapeutic modality with the potential to treat and even cure a diverse array of diseases. Cell therapies offer unique clinical and therapeutic advantages over conventional small molecules and the growing number of biologics. Particularly, living cells can simultaneously and dynamically perform complex biological functions in ways that conventional drugs cannot; cell therapies have expanded the spectrum of available therapeutic options to include key cellular functions and processes. As such, cell therapies are currently one of the most investigated therapeutic modalities in both preclinical and clinical settings, with many products having been approved and many more under active clinical investigation. Here, we highlight the diversity and key advantages of cell therapies and discuss their current clinical advances. In particular, we review 28 globally approved cell therapy products and their clinical use. We also analyze >1700 current active clinical trials of cell therapies, with an emphasis on discussing their therapeutic applications. Finally, we critically discuss the major biological, manufacturing, and regulatory challenges associated with the clinical translation of cell therapies.

Pluripotent and Multipotent Stem Cells and Current Therapeutic Applications: Review

There is numerous evidence for the presence of stem cells, which is important for the treatment of a wide variety of disease conditions. Stem cells have a great therapeutic effect on different degenerative diseases through the development of specialized cells. Embryonic stem (ES) cells are derived from preimplantation embryos, which have a natural karyotype. This cell has the capacity of proliferation indefinitely and undifferentiated. Stem cells are very crucial for the treatment of different chronic and degenerative diseases. For instance, stem cell clinical trials have been done for ischemic heart disease. Also, the olfactory cells for spinal cord lesions and human fetal pancreatic cells for diabetes mellitus are the other clinical importance of stem cell therapy. Extracellular matrix (ECM) and other environmental factors influence the fate and activity of stem cells.

The preclinical and clinical implications of fetal adnexa derived mesenchymal stromal cells in wound healing therapy

Mesenchymal stromal cells (MSCs) isolated from fetal adnexa namely amniotic membrane/epithelium, amniotic fluid and umbilical cord have hogged the limelight in recent times, as a proposed alternative to MSCs from conventional sources. These cells which are identified as being in a developmentally primitive state have many advantages, the most important being the non-invasive nature of their isolation procedures, absence of ethical concerns, proliferation potential, differentiation abilities and low immunogenicity. In the present review, we are focusing on the potential preclinical and clinical applications of different cell types of fetal adnexa, in wound healing therapy. We also discuss the isolation-culture methods, cell surface marker expression, multi-lineage differentiation abilities, immune-modulatory capabilities and their homing property. Different mechanisms involved in the wound healing process and the role of stromal cells in therapeutic wound healing are highlighted. Further, we summarize the findings of the cell delivery systems in skin lesion models and paracrine functions of their secretome in the wound healing process. Overall, this holistic review outlines the research findings of fetal adnexa derived MSCs, their usefulness in wound healing therapy in human as well as in veterinary medicine.

Urine stem cells are equipped to provide B cell survival signals

The interplay between mesenchymal stem cells (MSCs) and immune cells has been studied for MSCs isolated from different tissues. However, the immunomodulatory capacity of urine stem cells (USCs) has not been adequately researched. The present study reports on the effect of USCs on peripheral blood lymphocytes. USCs were isolated and characterized before coculture with resting and with anti‐CD3/CD28 bead stimulated lymphocytes. Similarly to bone marrow mesenchymal stem cells (BM‐MSCs), USCs inhibited the proliferation of activated T lymphocytes and induced their apoptosis. However, they also induced strong activation, proliferation, and cytokine and antibody production by B lymphocytes. Molecular phenotype and supernatant analysis revealed that USCs secrete a range of cytokines and effector molecules, known to play a central role in B cell biology. These included B cell‐activating factor (BAFF), interleukin 6 (IL‐6) and CD40L. These findings raise the possibility of an unrecognized active role for kidney stem cells in modulating local immune cells.

Therapeutic potential of stem cells for preterm infant brain damage: Can we move from the heterogeneity of preclinical and clinical studies to established therapeutics?

Acquired perinatal brain injuries are a set of conditions that remains a key challenge for neonatologists and that have significant social, emotional and financial implications for our communities. In our perspective article, we will introduce perinatal brain injury focusing specifically on the events leading to brain damage in preterm born infants and outcomes for these infants. Then we will summarize and discuss the preclinical and clinical studies testing the efficacy of stem cells as neuroprotectants in the last ten years in perinatal brain injury. There are no therapies to treat brain damage in preterm born infants and a primary finding from this review is that there is a scarcity of stem cell trials focused on overcoming brain injuries in these infants. Overall, across all forms of perinatal brain injury there is a remarkable heterogeneity in previous and on-going preclinical and clinical studies in terms of the stem cell type, animal models/patient selection, route and time of administration. Despite the quality of many of the studies this variation makes it difficult to reach a valid consensus for future developments. However, it is clear that stem cells (and stem cell derived exosomes) can reduce perinatal brain injury and our field needs to work collectively to refine an effective protocol for each type of injury. The use of standardized stem cell products and testing these products across multiple models of injury will provide a stronger framework for clinical trials development.

Regenerative Medicine in COVID-19 Treatment: Real Opportunities and Range of Promises

Novel coronavirus disease (COVID-19) has attracted much attention around the world due to its rapid transmission among humans and relatively high mortality rate. Studies are increasing to find the best therapeutic approach for the disease and its management. Regenerative medicine offers various cell-tissue therapeutics and related products, such as stem cell therapy, natural killer (NK) cell therapy, Chimeric antigen receptor (CAR) T cell therapy, exosomes, and tissue products. Interestingly, mesenchymal stem cells (MSCs) can reduce inflammatory symptoms and protect against cytokine storm, which critically contributes to the COVID-19 progression. Notably, having the potentials to exert cytotoxic effects on infected cells and induce interferon production probably make NK cells a candidate for COVID-19 cell therapy. Besides, exosomes are one of the crucial products of cells that can exert therapeutic effects through the induction of immune responses and neutralizing antibody titers. The paper aims to briefly consider current options for COVID-19 therapy to show that there is no specific cure for COVID-19, and then assess the real opportunities and range of promises regenerative medicine can provide for specific treatment of COVID-19. Graphical Abstract Therapeutic Potential of Regenerative Medicine against COVID19.

Human Dental Pulp-Derived Mesenchymal Stem Cell Potential to Differentiate into Smooth Muscle-Like Cells In Vitro

Previous studies have shown that mesenchymal stem cells (MSCs) derived from various tissue sources can be differentiated into smooth muscle-like cells (SMLCs) in vitro. In this paper, dental pulp-derived mesenchymal stem cells (DPSCs) were evaluated for their differentiation ability towards smooth muscle-like cells (SMLCs) under the effect of widely used cytokines (TGF-β1 and PDGF-BB) with special focus on different culturing environments. For this purpose, both the commercially used culturing plates (Norm-c) and 0.1% gelatin-precoated (Gel-c) plates were used. Isolated cells displayed plastic adherence, pluripotency and cell surface marker profiling, and adipogenic and osteogenic differentiation potential with lineage specific marker expression. Differentiated cells induced under different culturing plates showed successful differentiation into SMLCs by positively expressing smooth muscle cell (SMC) specific markers both at the mRNA and protein levels. Gelatin coating could substantially enhance DPSC differentiation potential than Norm-c-induced cells. However, the absence of mature marker MHY-11 by immunostaining results from all treatment groups further indicated the development of immature and synthetic SMLCs. Finally, it was concluded that DPSC differentiation ability into SMLCs can be enhanced under cytokine treatment as well as by altering the cellular niche by precoating the culturing plates with suitable substrates. However, to get fully functional, contractile, and mature SMLCs, still many different cytokine cocktail combinations and more suitable coating substrates will be needed.

Hypoxic Preconditioning of Human Umbilical Cord Mesenchymal Stem Cells Is an Effective Strategy for Treating Acute Lung Injury

Acute respiratory distress syndrome (ARDS)/acute lung injury (ALI) is a severe clinical respiratory failure disorder associated with chronic pathology and disability and has a mortality rate of 40%-60%. However, the pathogenesis of ARDS/ALI remains unclear, and existing therapeutic options are insufficient for addressing the severity of the disease. Mesenchymal stem cells (MSCs) play an important role in the prevention and treatment of ALI, especially acute alveolar epithelial injury. However, the low survival rate of transplanted MSCs reduces their effectiveness. When human umbilical cord MSCs (hUC-MSCs) are transplanted directly, only a minority of cells migrate toward damaged tissues. Moreover, their maintenance time is short, leading to unsatisfactory therapeutic results. A moderate hypoxic environment can promote the proliferation of MSCs, inhibit apoptosis, and facilitate migration and chemotaxis. In summary, hypoxic culturing before transplantation improves the effectiveness of hUC-MSCs in treating ARDS/ALI and promises to provide novel diagnostic and therapeutic targets.

Adult Renal Stem/Progenitor Cells Can Modulate T Regulatory Cells and Double Negative T Cells

Adult Renal Stem/Progenitor Cells (ARPCs) have been recently identified in the human kidney and several studies show their active role in kidney repair processes during acute or chronic injury. However, little is known about their immunomodulatory properties and their capacity to regulate specific T cell subpopulations. We co-cultured ARPCs activated by triggering Toll-Like Receptor 2 (TLR2) with human peripheral blood mononuclear cells for 5 days and 15 days and studied their immunomodulatory capacity on T cell subpopulations. We found that activated-ARPCs were able to decrease T cell proliferation but did not affect CD8⁺ and CD4⁺ T cells. Instead, Tregs and CD3⁺ CD4^- CD8^- double-negative (DN) T cells decreased after 5 days and increased after 15 days of co-culture. In addition, we found that PAI1, MCP1, GM-CSF, and CXCL1 were significantly expressed by TLR2-activated ARPCs alone and were up-regulated in T cells co-cultured with activated ARPCs. The exogenous cocktail of cytokines was able to reproduce the immunomodulatory effects of the co-culture with activated ARPCs. These data showed that ARPCs can regulate immune response by inducing Tregs and DN T cells cell modulation, which are involved in the balance between immune tolerance and autoimmunity.

Recent advances in mesenchymal stem cell membrane-coated nanoparticles for enhanced drug delivery

Studies of nanomedicine have achieved dramatic progress in recent decades. However, the main challenges that traditional nanomedicine has to overcome include low accumulation at target sites and rapid clearance from the blood circulation. An interesting approach using cell membrane coating technology has emerged as a possible way to overcome these limitations, owing to the enhanced targeted delivery and reduced immunogenicity of cell membrane moieties. Mesenchymal stem cell (MSC) therapy has been investigated for treating various diseases, ranging from inflammatory diseases to tissue damage. Recent studies with engineered modified MSCs or MSC membranes have focused on enhancing cell therapeutic efficacy. Therefore, bioengineering strategies that couple synthetic nanoparticles with MSC membranes have recently received much attention due to their homing ability and tumor tropism. Given the various membrane receptors on their surfaces, MSC membrane-coated nanoparticles are an effective method with selective targeting properties, allowing entry into specific cells. Here, we review recent progress on the use of MSC membrane-coated nanoparticles for biomedical applications, particularly in the two main antitumor and anti-inflammatory fields. The combination of a bioengineered cell membrane and synthesized nanoparticles presents a wide range of possibilities for the further development of targeted drug delivery, showing the potential to enhance the therapeutic efficacy for treating various diseases.

Chemokine SDF1 Mediated Bone Regeneration Using Biodegradable Poly(D,L-lactide-co-glycolide) 3D Scaffolds and Bone Marrow-Derived Mesenchymal Stem Cells: Implication for the Development of an "Off-the-Shelf" Pharmacologically Active Construct

There is an increasing need for bone substitutes for reconstructive orthopedic surgery following removal of bone tumors. Despite the advances in bone regeneration, the use of autologous mesenchymal stem cells (MSC) presents a significant challenge, particularly for the treatment of large bone defects in cancer patients. This study aims at developing new chemokine-based technology to generate biodegradable scaffolds that bind pharmacologically active proteins for regeneration/repair of target injured tissues in patients. Primary MSC were cultured from the uninvolved bone marrow (BM) of cancer patients and further characterized for "stemness". Their ability to differentiate into an osteogenic lineage was studied in 2D cultures as well as on 3D macroporous PLGA scaffolds incorporated with biomacromolecules bFGF and homing factor chemokine stromal-cell derived factor-1 (SDF1). MSC from the uninvolved BM of cancer patients exhibited properties similar to that reported for MSC from BM of healthy individuals. Macroporous PLGA discs were prepared and characterized for pore size, architecture, functional groups, thermostability, and cytocompatibility by ESEM, FTIR, DSC, and CCK-8 dye proliferation assay, respectively. It was observed that the MSC+PLGA+bFGF+SDF1 construct cultured for 14 days supported significant cell growth, osteo-lineage differentiation with increased osteocalcin expression, alkaline phosphatase secretion, calcium mineralization, bone volume, and soluble IL6 compared to unseeded PLGA and PLGA+MSC, as analyzed by confocal microscopy, biochemistry, ESEM, microCT imaging, flow cytometry, and EDS. Thus, chemotactic biomacromolecule SDF1-guided tissue repair/regeneration ability of MSC from cancer patients opens up the avenues for development of "off-the-shelf" pharmacologically active construct for optimal repair of the target injured tissue in postsurgery cancer patients, bone defects, damaged bladder tissue, and radiation-induced skin/mucosal lesions.

Mesenchymal stem cell therapies for COVID-19: Current status and mechanism of action

The outbreak of COVID-19 in December 2019, has become an urgent and serious public health emergency. At present, there is no effective treatment or vaccine for COVID-19. Therefore, there is a crucial unmet need to develop a safe and effective treatment for COVID-19 patients. Mesenchymal stem cells (MSCs) are widely used in basic science and in a variety of clinical trials. MSCs are able to engraft to the damaged tissues after transplantation and promote tissue regeneration, besides MSCs able to secrete immunomodulatory factors that suppress the cytokine storms. Moreover, the contribution of MSCs to prevent cell death and inhibit tissue fibrosis is well established. In the current review article, the potential mechanisms by which MSCs contribute to the treatment of COVID-19 patients are highlighted. Also, current trials that evaluated the potential of MSC-based treatments for COVID-19 are briefly reviewed.

Evaluation of the Effectiveness of Mesenchymal Stem Cells of the Placenta and Their Conditioned Medium in Local Radiation Injuries

BACKGROUND

The search for an effective therapy for local radiation injuries (LRI) is urgent; one option is mesenchymal stem cells (MSC) derived from the placenta and their conditioned medium for the regenerative processes of the skin.

METHODS

We used 80 animals, randomly assigned to four groups: control (C) animals that did not receive therapy; control with the introduction of culture medium concentrate (CM); introduction of MSCs (PL); introduction of CMPL. LRI modeling was performed on an X-ray machine at a dose of 110 Gy. Histological and immunohistochemical tests were performed.

RESULTS

On the 112th day, the area of the open wound surface in the CMPL group was 6.7 times less than in the control group. Complete healing of the open wound surface of the skin in the CM group was observed in 40%, in CMPL 60%, in the PL group 20%, and in the C group there were no animals with a prolonged wound defect. A decrease in inflammatory processes was observed in the CMPL group.

CONCLUSIONS

the use of a concentrate of conditioned MSCs (CMPL group) in severe LRI in laboratory animals accelerates the transition of the wound process to the stage of regeneration and epithelization.

Growth differentiation factor 6, a repressive target of EZH2, promotes the commitment of human embryonic stem cells to mesenchymal stem cells

Mesenchymal stem cells (MSCs) derived from human embryonic stem cells (hESCs) have significant potential for cell-mediated bone regeneration. Our recent study revealed that inhibiting the epigenetic regulator EZH2 plays a key role in promoting the mesodermal differentiation of hESCs. In this study, an epigenome-wide analysis of hESCs and MSCs revealed that growth differentiation factor 6 (GDF6), which is involved in bone formation, was the most upregulated gene associated with MSCs compared to hESCs. Furthermore, we identified GDF6 as a repressive target of EZH2 and found that ectopic GDF6 selectively promoted hESC differentiation towards the mesodermal lineage and enriched the MSC population. Our results provide molecular insights governing the mesenchymal commitment of hESCs and identify an inducing factor that offers strong promise for the future of regenerative medicine.

Protein quality control of cell stemness

Protein quality control (PQC) systems play essential roles in the recognition, refolding and clearance of aberrant proteins, thus ensuring cellular protein homeostasis, or proteostasis. Especially, continued proliferation and differentiation of stem cells require a high rate of translation; therefore, accurate PQC systems are essential to maintain stem cell function. Growing evidence suggested crucial roles of PQC systems in regulating the stemness and differentiation of stem cells. This review focuses on current knowledge regarding the components of the proteostasis network in stem cells, and the importance of proteostasis in maintaining stem cell identity and regenerative functions. A complete understanding of this process might uncover potential applications in aging intervention and aging-related diseases.

Evidence for the existence of CD34+ angiogenic stem cells in human first-trimester decidua and their therapeutic for ischaemic heart disease

Stem cell transplantation is nearly available for clinical application in the treatment of ischaemic heart disease (IHD), where it may be joined traditional methods (intervention and surgery). The angiogenic ability of seed cells is essential for this applicability. The aim of this study was to reveal the presence of CD34⁺ angiogenic stem cells in human decidua at the first trimester and to use their strong angiogenic capacity in the treatment of IHD. In vitro, human decidual CD34⁺ (dCD34⁺) cells from the first trimester have strong proliferation and clonality abilities. After ruling out the possibility that they were vascular endothelial cells and mesenchymal stem cells (MSCs), dCD34⁺ cells were found to be able to form tube structures after differentiation. Their angiogenic capacity was obviously superior to that of bone marrow mesenchymal stem cells (BMSCs). At the same time, these cells had immunogenicity similar to that of BMSCs. Following induction of myocardial infarction (MI) in adult rats, infarct size decreased and cardiac function was significantly enhanced after dCD34⁺ cell transplantation. The survival rate of cells increased, and more neovasculature was found following dCD34⁺ cell transplantation. Therefore, this study confirms the existence of CD34⁺ stem cells with strong angiogenic ability in human decidua from the first trimester, which can provide a new option for cell‐based therapies for ischaemic diseases, especially IHD.

COVID-19: An insight into the developments in diagnostics and therapeutics in India

The unexpected pandemic set off by the novel coronavirus (SARS-CoV2) has spread to more than 210 countries across the globe, including India. In the current pandemic situation, various steps have been taken by the Indian government to prevent and control the spread of the SARS-CoV2 infection. To date, there are no proven vaccines or effective therapeutic interventions against the virus. Current clinical management includes infection prevention and control, symptom-specific relief and supportive care. Physicians and scientists across the country have been tirelessly working on developing effective diagnostic and therapeutic strategies and to combat and control this infection. As the demand for diagnostics and therapeutics continues to rise in India and around the globe, it is essential to rapidly develop various algorithms to successfully identify and contain the virus. This review discusses the updates on the recent developments in COVID-19 diagnostics and therapeutics in India.

Seaweed polysaccharide derived bioaldehyde nanocomposite: Potential application in anticancer therapeutics

In the present study, we have demonstrated synthesis of agar aldehyde (A_ald) from seaweed polysaccharide and its further successful application for preparation of A_ald mediated solid silver nanocomposite (A_ald-AgNPs). A_ald-AgNPs were characterized for biophysical properties by FTIR, XRD, SEM, TEM, XPS, and UV-vis spectroscopy. A_ald-AgNPs were further tested in vitro and in vivo for anticancer activity. The results of the in vitro study revealed that A_ald-AgNPs exhibited activity against 3 cancer cell lines. A_ald-AgNPs were found to act through causing dose dependent increase in cell size, inducing anueploidy, mitochondrial disintegration and increasing septa formation in cell cytoplasm. Results of in vivo anticancer activity against ME-180, Colon-26, and HL-60 xenograft mice tumor models showed 64 %, 27.3 % and 51 % reduction in tumor volume, respectively with 83-100 % survival rate. A_ald-AgNPs exhibited excellent antibacterial activity. It was interesting to note that A_ald-AgNPs did not exhibit any significant detrimental effect on viability and metabolic activity of normal bone marrow derived mesenchymal stem cells. This study opens new areas of research for chemists and biologists to use seaweed-derived polymers to develop nanocomposites for cancer therapeutics.

Mesenchymal stromal cells (MSCs) for neurodegenerative disease: A promising frontier

Neurodegenerative disorders are a variety of diseases including Alzheimer's (AD), Parkinson's (PD), and Huntington's diseases (HD), multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS) along with some other less common diseases generally described by the advanced deterioration of central or peripheral nervous system, structurally or functionally. In the last two decades, mesenchymal stromal cells (MSCs) due to their unique assets encompassing self-renewal, multipotency and accessibility in association with low ethical concern open new frontiers in the context of neurodegenerative diseases therapy. Interestingly, MSCs can be differentiated into endodermal and ectodermal lineages (e.g., neurons, oligodendrocyte, and astrocyte), and thus could be employed to advance cell-based therapeutic strategy. Additionally, as inflammation ordinarily ensues as a local response provoked by microglia in the neurodegenerative diseases, MSCs therapy because of their pronounced immunomodulatory properties is noticed as a rational approach for their treatment. Recently, varied types of studies have been mostly carried out in vitro and rodent models using MSCs upon their procurement from various sources and expansion. The promising results of the studies in rodent models have motivated researchers to design and perform several clinical trials, with a speedily rising number. In the current review, we aim to deliver a brief overview of MSCs sources, expansion strategies, and their immunosuppressive characteristics and discuss credible functional mechanisms exerted by MSCs to treat neurodegenerative disorders, covering AD, PD, ALS, MS, and HD.

Safety and immunomodulatory properties of equine peripheral blood-derived mesenchymal stem cells in healthy cats

OBJECTIVE

Due to the immunomodulatory properties of mesenchymal stem cells (MSCs) through stimulation of endogenous immune cells by paracrine signals and cell contact, they have been proposed as alternative treatment option for many inflammatory and immune-mediated diseases in veterinary medicine. However, the long-term cultivation possibilities of feline MSCs are currently compromised due to a restricted proliferation capacity. Therefore, the xenogeneic use of equine peripheral blood-derived MSCs (ePB-MSCs) would present an interesting alternative thanks to their superior cultivation properties. To the authors' knowledge, there are currently no safety reports concerning the xenogeneic use of ePB-MSCs in cats. Therefore, the overall goal of this preliminary study was to investigate if ePB-MSCs can safely be administered in healthy cats and by extension evaluating their immunogenic and immunomodulatory properties.

METHODS

Ten healthy cats were intravenously (i.v.) injected with 3 × 10⁵ ePB-MSCs at three time points (T₀, T₁, T₂). All cats were daily inspected by the caretaker and underwent a physical examination with hematological and biochemical analysis at day 0 (T₀), week 2 (T₁), week 4 (T₂) and week 6 (T₃) by a veterinarian. Furthermore, a modified mixed lymphocyte reaction (MLR) was performed at T₀ and T₃ for each cat in order to evaluate immunogenic and immunomodulatory properties of the ePB-MSCs RESULTS: No adverse clinical effects could be detected following repeated i.v. administration of ePB-MSCs in all cats. Significant lower protein (T₁: P-value = 0.002; T₂: P-value > 0.001; T₃: P-value = 0.004) and albumin levels (T₁: P-value = 0.003; T₂: P-value = 0.001) were seen after repeated administration of ePB-MSCs, compared to T₀. However, all biochemical and hematological parameters stayed within clinical acceptance level. In addition, the repeated injections did not induce a cellular immune response before and after repeated ePB-MSCs administration. Furthermore, convincing immunomodulatory properties of ePB-MSCs on feline peripheral blood mononuclear cells were confirmed in the MLR-assay CONCLUSION: This preliminary study demonstrates that ePB-MSCs can safely be administered in healthy cats and provide a promising alternative for the treatment of various inflammatory diseases in cats.