Endothelial progenitor cells promote viability and nerve regenerative ability of mesenchymal stem cells through PDGF-BB/PDGFR-β signaling

Development of stem cell therapy for atherosclerosis

Cardiovascular disease (CVD) has a high incidence and low cure rate worldwide, and atherosclerosis (AS) is the main factor inducing cardiovascular disease, of which lipid deposition in the vessel wall is the main marker of AS. Currently, although statins can be used to lower lipids and low-density lipoprotein (LDL) in AS, the cure rate for AS remains low. Therefore, there is an urgent need to develop new therapeutic approaches, and stem cells are now widely studied, while stem cells are a class of cell types that always maintain the ability to differentiate and can differentiate to form other cells and tissues, and stem cell transplantation techniques have shown efficacy in the treatment of other diseases. With the establishment of cellular therapies and continued research in stem cell technology, stem cells are also being used to address the problem of AS. In this paper, we focus on recent research advances in stem cell therapy for AS and briefly summarize the relevant factors that induce the formation of AS. We mainly discuss the efficacy and application prospects of mesenchymal stem cells (MSCs) for the treatment of AS, in addition to the partial role and potential of exosomes in the treatment of AS. Further, provide new ideas for the clinical application of stem cells.

Nrf2 enhances the therapeutic efficiency of adipose-derived stem cells in the treatment of neurogenic erectile dysfunction in a rat model

BACKGROUND

Erectile dysfunction (ED) caused by intraoperative nerve injury is a major complication of pelvic surgery. Adipose-derived stem cells (ADSCs) have presented therapeutic potential in a rat model of bilateral cavernous nerve injury (BCNI), while inadequate in vivo viability has largely limited their application. Nuclear factor-E2-related Factor (Nrf2) is a key transcription factor that regulates cellular anti-oxidative stress. In this work, we investigated the effect of Nrf2 expression regulation on the viability of ADSCs, and explore its repair potential in a BCNI rat model.

RESULTS

The survival time of tert-Butylhydroquinone (tBHQ)-ADSCs in BCNI model increased obviously. In addition, the tBHQ-ADSCs group presented better restoration of major pelvic ganglion (MPG) nerve contents and fibers, better improvement of erectile function, and less penile fibrosis than the other groups. Moreover, the expression of Nrf2 and superoxide dismutase 1 (SOD1) were higher than those of other groups.

CONCLUSION

Nrf2 could enhance the anti-oxidative stress ability of ADSCs, so as to improve the therapeutic effect of ADSCs on BCNI rat model.

Platelet-Derived Growth Factor-BB Priming Enhances Vasculogenic Capacity of Bone Marrow-Derived Endothelial Precursor Like Cells

BACKGROUND

Human endothelial progenitor cells (EPCs) were first identified in the peripheral blood and later in the cord blood and bone marrow (BM) with different vascularization capacity and different surface marker profiles. However, their identity and functional roles in neovascularization have not been clearly demonstrated in vivo and in vitro.

METHODS

Characterization of BM-EPC like cells were performed by fluorescence-activated cell sorting, immunofluorescence staining, enzyme-linked immunosorbent assay, Matrigel tube formation assay, and western blot analysis.

RESULTS

BM-EPC like cells were identified by selective adhesion to fibronectin and collagen from BM mononuclear cells, which generate fast-growing colonies with spindle morphology, express surface markers of CD105, vWF, UEA-I lectin binding, secrete HGF, VEGF, TGF-beta1 but can be distinguished from circulating EPC and endothelial cells by no expression of surface markers such as CD31, CD309, CD45, and CD34. These BM-EPC like cells shared many cell surface markers of BM-mesenchymal stem cells (MSC) but also can be distinguished by their vasculogenic property and other unique surface markers. Furthermore, the vasculogenic capacity of BM-EPC like cells were enhanced by co-culture of BM-MSC or PDGF-BB priming. PDGF-BB stimulated cell migration, proliferation, and secretion of laminin β-1, which was proposed as one of the mechanisms involved in the better vascularization of BM-EPC like cells.

CONCLUSION

PDGF-BB priming may be applied to improve the potency and function of BM-EPC like cells as vasculogenic cell therapy for the ischemic vascular repair.

New insights about the PDGF/PDGFR signaling pathway as a promising target to develop cancer therapeutic strategies

Numerous cancers express platelet-derived growth factors (PDGFs) and PDGF receptors (PDGFRs). By directly stimulating tumour cells in an autocrine manner or by stimulating tumour stromal cells in a paracrine manner, the platelet-derived growth factor (PDGF)/platelet-derived growth factor receptor (PDGFR) pathway is crucial in the growth and spread of several cancers. To combat hypoxia in the tumour microenvironment, it encourages angiogenesis. A growing body of experimental data shows that PDGFs target malignant cells, vascular cells, and stromal cells to modulate tumour growth, metastasis, and the tumour microenvironment. To combat medication resistance and enhance patient outcomes in cancers, targeting the PDGF/PDGFR pathway is a viable therapeutic approach. There have been reports of anomalies in the PDGF pathway, including the gain of function point mutations, activating chromosomal translocations, or overexpression or amplification of PDGF receptors (PDGFRs). As a result, it has been shown that targeting the PDGF/PDGFR signaling pathway is an effective method for treating cancer. As a result, this study will concentrate on the regulation of the PDGF/PDGFR signaling system, in particular the current methods and inhibitors used in cancer treatment, as well as the associated therapeutic advantages and side effects.

CD34 positive cells as endothelial progenitor cells in biology and medicine

CD34 is a cell surface antigen expressed in numerous stem/progenitor cells including hematopoietic stem cells (HSCs) and endothelial progenitor cells (EPCs), which are known to be rich sources of EPCs. Therefore, regenerative therapy using CD34⁺ cells has attracted interest for application in patients with various vascular, ischemic, and inflammatory diseases. CD34⁺ cells have recently been reported to improve therapeutic angiogenesis in a variety of diseases. Mechanistically, CD34⁺ cells are involved in both direct incorporation into the expanding vasculature and paracrine activity through angiogenesis, anti-inflammatory, immunomodulatory, and anti-apoptosis/fibrosis roles, which support the developing microvasculature. Preclinical, pilot, and clinical trials have well documented a track record of safety, practicality, and validity of CD34⁺ cell therapy in various diseases. However, the clinical application of CD34⁺ cell therapy has triggered scientific debates and controversies in last decade. This review covers all preexisting scientific literature and prepares an overview of the comprehensive biology of CD34⁺ cells as well as the preclinical/clinical details of CD34⁺ cell therapy for regenerative medicine.

Artificial nerve graft constructed by coculture of activated Schwann cells and human hair keratin for repair of peripheral nerve defects

Studies have shown that human hair keratin (HHK) has no antigenicity and excellent mechanical properties. Schwann cells, as unique glial cells in the peripheral nervous system, can be induced by interleukin-1β to secrete nerve growth factor, which promotes neural regeneration. Therefore, HHK with Schwann cells may be a more effective approach to repair nerve defects than HHK without Schwann cells. In this study, we established an artificial nerve graft by loading an HHK skeleton with activated Schwann cells. We found that the longitudinal HHK microfilament structure provided adhesion medium, space and direction for Schwann cells, and promoted Schwann cell growth and nerve fiber regeneration. In addition, interleukin-1β not only activates Schwann cells, but also strengthens their activity and increases the expression of nerve growth factors. Activated Schwann cells activate macrophages, and activated macrophages secrete interleukin-1β, which maintains the activity of Schwann cells. Thus, a beneficial cycle forms and promotes nerve repair. Furthermore, our studies have found that the newly constructed artificial nerve graft promotes the improvements in nerve conduction function and motor function in rats with sciatic nerve injury, and increases the expression of nerve injury repair factors fibroblast growth factor 2 and human transforming growth factor B receptor 2. These findings suggest that this artificial nerve graft effectively repairs peripheral nerve injury.

The Microenvironment That Regulates Vascular Wall Stem/Progenitor Cells in Vascular Injury and Repair

Vascular repair upon injury is a frequently encountered pathology in cardiovascular diseases, which is crucial for the maintenance of arterial homeostasis and function. Stem/progenitor cells located on vascular walls have multidirectional differentiation potential and regenerative ability. It has been demonstrated that stem/progenitor cells play an essential role in the basic medical research and disease treatment. The dynamic microenvironment around the vascular wall stem/progenitor cells (VW-S/PCs) possesses many stem cell niche-like characteristics to support and regulate cells' activities, maintaining the properties of stem cells. Under physiological conditions, vascular homeostasis is a cautiously balanced and efficient interaction between stem cells and the microenvironment. These interactions contribute to the vascular repair and remodeling upon vessel injury. However, the signaling mechanisms involved in the regulation of microenvironment on stem cells remain to be further elucidated. Understanding the functional characteristics and potential mechanisms of VW-S/PCs is of great significance for both basic and translational research. This review underscores the microenvironment-derived signals that regulate VW-S/PCs and aims at providing new targets for the treatment of related cardiovascular diseases.

Case series of the first three severe COVID-19 patients treated with the secretome of hypoxia-mesenchymal stem cells in Indonesia

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the outbreak of coronavirus disease 2019 (COVID-19), which has been rapidly spreading. Several guideline therapies have been proposed as a possible treatment for SARS-CoV-2, however, these therapies are not sufficient to treat a severe condition of SARS-CoV-2 infection characterised by the increase of D-dimer and C-reactive protein (CRP) levels, and patchy ground-glass opacities (GGOs). Secretome-mesenchymal stem cells (S-MSCs) produced by MSCs under hypoxia could excessively release several anti-inflammatory cytokines and growth factors to control the COVID-19 cytokine storm and accelerate lung injury improvement. This is the first study investigating the clinical outcomes of three severe COVID-19 patients admitted to the intensive care unit of three different hospitals in Indonesia treated with S-MSCs. The decrease of D-dimer and CRP level was reported for all patients treated with S-MSCs. This was in line with improvement of pulmonary radiology, blood gas level, and hematologic assessment. In conclusion, these cases suggest that S-MSCs could effectively control D-dimer, CRP level and GGOs of severe COVID-19 patients associated with recovered pulmonary function.

Molecular Dynamics of Cytokine Interactions and Signalling of Mesenchymal Stem Cells Undergoing Directed Neural-like Differentiation

Mesenchymal stem cells are a continually expanding area in research and clinical applications. Their usefulness and capacity to differentiate into various cells, particularly neural types, has driven the research area for several years. Neural differentiation has considerable usefulness. There are several successful differentiation techniques of mesenchymal stem cells that employ the use of small molecules, growth factors and commercially available kits and supplements. Phenotyping, molecular biology, genomics and proteomics investigation revealed a wealth of data about these cells during neurogenic differentiation. However, there remain large gaps in the knowledge base, particularly related to cytokines and how their role, drive mechanisms and the downstream signalling processes change with their varied expression throughout the differentiation process. In this study, adult mesenchymal stem cells were induced with neurogenic differentiation media, the cellular changes monitored by live-cell microscopy and the changes in cytokine expression in the intracellular region, secretion into the media and in the extracellular vesicle cargo were examined and analysed bioinformatically. Through this analysis, the up-regulation of key cytokines was revealed, and several neuroprotective and neurotrophic roles were displayed. Statistically significant molecules IFN-G, IL1B, IL6, TNF-A, have roles in astrocyte development. Furthermore, the cytokine bioinformatics suggests the Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) pathway is upregulated, supporting differentiation toward an astroglial lineage.

Paracrine mechanisms of endothelial progenitor cells in vascular repair

Endothelial progenitor cells (EPCs) play an important role in repairing damaged blood vessels and promoting neovascularization. However, the specific mechanism of EPCs promoting vascular repair is still unclear. Currently, there are two different views on the repair of damaged vessels by EPCs, one is that EPCs can directly differentiate into endothelial cells (ECs) and integrate into injured vessels, the other is that EPCs act on cells and blood vessels by releasing paracrine substances. But more evidence now supports the latter. Therefore, the paracrine mechanisms of EPCs are worth further study. This review describes the substances secreted by EPCs, some applications based on paracrine effects of EPCs, and the studies of paracrine mechanisms in cardiovascular diseases--all of these are to support the view that EPCs repair blood vessels through paracrine effects rather than integrating directly into damaged vessels.

Case series of the first three severe COVID-19 patients treated with the secretome of hypoxia-mesenchymal stem cells in Indonesia

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the outbreak of coronavirus disease 2019 (COVID-19), which has been rapidly spreading. Several guideline therapies have been proposed as a possible treatment for SARS-CoV-2, however, these therapies are not sufficient to treat a severe condition of SARS-CoV-2 infection characterised by the increase of D-dimer and C-reactive protein (CRP) levels, and patchy ground-glass opacities (GGOs). Secretome-mesenchymal stem cells (S-MSCs) produced by MSCs under hypoxia could excessively release several anti-inflammatory cytokines and growth factors to control the COVID-19 cytokine storm and accelerate lung injury improvement. This is the first study investigating the clinical outcomes of three severe COVID-19 patients admitted to the intensive care unit of three different hospitals in Indonesia treated with S-MSCs. The decrease of D-dimer and CRP level was reported for all patients treated with S-MSCs. This was in line with improvement of pulmonary radiology, blood gas level, and hematologic assessment. In conclusion, these cases suggest that S-MSCs could effectively control D-dimer, CRP level and GGOs of severe COVID-19 patients associated with recovered pulmonary function.

Transplantation of Human Gingiva-Derived Mesenchymal Stem Cells Ameliorates Neurotic Erectile Dysfunction in a Rat Model

Cavernous nerve injury (CNI) is the main cause of erectile dysfunction (ED) following pelvic surgery. Our previous studies have demonstrated that transplantation of different sources of mesenchymal stem cells (MSCs) was able to alleviate ED induced by CNI in rat models. However, little is known about the therapeutic effects of human gingiva-derived MSCs (hGMSCs) in CNI ED rats. Herein, we injected the hGMSCs around the bilateral major pelvic ganglia (MPG) in a rat model of CNI and evaluated their efficacy. The results showed that treatment of hGMSCs could significantly promote the recovery of erectile function, enhance smooth muscle and endothelial content, restore neuronal nitric oxide synthase (nNOS) expression, and attenuate cell apoptosis in penile tissue. Moreover, penile fibrosis was significantly alleviated after hGMSC administration. In addition, potential mechanism exploration indicated that hGMSCs might exert its functions via skewed macrophage polarity from M1 toward M2 anti-inflammatory phenotype. In conclusion, this study found that transplantation of hGMSCs significantly improved CNI-related ED, which might provide new clues to evaluate their pre-clinical application.

Case series of the first three severe COVID-19 patients treated with the secretome of hypoxia-mesenchymal stem cells in Indonesia

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the outbreak of coronavirus disease 2019 (COVID-19), which has been rapidly spreading. Several guideline therapies have been proposed as a possible treatment for SARS-CoV-2, however, these therapies are not sufficient to treat a severe condition of SARS-CoV-2 infection characterised by the increase of D-dimer and C-reactive protein (CRP) levels, and patchy ground-glass opacities (GGOs). Secretome-mesenchymal stem cells (S-MSCs) produced by MSCs under hypoxia could excessively release several anti-inflammatory cytokines and growth factors to control the COVID-19 cytokine storm and accelerate lung injury improvement. This is the first study investigating the clinical outcomes of three severe COVID-19 patients admitted to the intensive care unit of three different hospitals in Indonesia treated with S-MSCs. The decrease of D-dimer and CRP level was reported for all patients treated with S-MSCs. This was in line with improvement of pulmonary radiology, blood gas level, and hematologic assessment. In conclusion, these cases suggest that S-MSCs could effectively control D-dimer, CRP level and GGOs of severe COVID-19 patients associated with recovered pulmonary function.

Neovascularization: The Main Mechanism of MSCs in Ischemic Heart Disease Therapy

Mesenchymal stem cell (MSC) transplantation after myocardial infarction (MI) has been shown to effectively limit the infarct area in numerous clinical and preclinical studies. However, the primary mechanism associated with this activity in MSC transplantation therapy remains unclear. Blood supply is fundamental for the survival of myocardial tissue, and the formation of an efficient vascular network is a prerequisite for blood flow. The paracrine function of MSCs, which is throughout the neovascularization process, including MSC mobilization, migration, homing, adhesion and retention, regulates angiogenesis and vasculogenesis through existing endothelial cells (ECs) and endothelial progenitor cells (EPCs). Additionally, MSCs have the ability to differentiate into multiple cell lineages and can be mobilized and migrate to ischemic tissue to differentiate into ECs, pericytes and smooth muscle cells in some degree, which are necessary components of blood vessels. These characteristics of MSCs support the view that these cells improve ischemic myocardium through angiogenesis and vasculogenesis. In this review, the results of recent clinical and preclinical studies are discussed to illustrate the processes and mechanisms of neovascularization in ischemic heart disease.

Biological Effects of a Three-Dimensionally Printed Ti6Al4V Scaffold Coated with Piezoelectric BaTiO3 Nanoparticles on Bone Formation

Bone defect repair at load-bearing sites is a challenging clinical problem for orthopedists. Defect reconstruction with implants is the most common treatment; however, it requires the implant to have good mechanical properties and the capacity to promote bone formation. In recent years, the piezoelectric effect, in which electrical activity can be generated due to mechanical deformation, of native bone, which promotes bone formation, has been increasingly valued. Therefore, implants with piezoelectric effects have also attracted great attention from orthopedists. In this study, we developed a bioactive composite scaffold consisting of BaTiO₃, a piezoelectric ceramic material, coated on porous Ti6Al4V. This composite scaffold showed not only appropriate mechanical properties, sufficient bone and blood vessel ingrowth space, and a suitable material surface topography but also a reconstructed electromagnetic microenvironment. The osteoconductive and osteoinductive properties of the scaffold were reflected by the proliferation, migration, and osteogenic differentiation of mesenchymal stem cells. The ability of the scaffold to support vascularization was reflected by the proliferation and migration of human umbilical vein endothelial cells and their secretion of VEGF and PDGF-BB. A well-established sheep spinal fusion model was used to evaluate bony fusion in vivo. Sheep underwent implantation with different scaffolds, and X-ray, micro-computed tomography, van Gieson staining, and elemental energy-dispersive spectroscopy were used to analyze bone formation. Isolated cervical angiography and visualization analysis were used to assess angiogenesis at 4 and 8 months after transplantation. The results of cellular and animal studies showed that the piezoelectric effect could significantly reinforce osteogenesis and angiogenesis. Furthermore, we also discuss the molecular mechanism by which the piezoelectric effect promotes osteogenic differentiation and vascularization. In summary, Ti6Al4V scaffold coated with BaTiO₃ is a promising composite biomaterial for repairing bone defects, especially at load-bearing sites, that may have great clinical translation potential.