Advances in the differentiation of pluripotent stem cells into vascular cells

Blood vessels constitute a closed pipe system distributed throughout the body,transporting blood from the heart to other organs and delivering metabolic waste products back to the lungs and kidneys.Changes in blood vessels are related to many disorders like stroke,myocardial infarction,aneurysm,and diabetes,which are important causes of death worldwide.Translational research for new appro-aches to disease modeling and effective treatment is needed due to the huge socio-economic burden on healthcare systems.Although mice or rats have been widely used,applying data from animal studies to human-specific vascular physiology and pathology is difficult.The rise of induced pluripotent stem cells(iPSCs)provides a reliable in vitro resource for disease modeling,regenerative medicine,and drug discovery because they carry all human genetic information and have the ability to directionally differentiate into any type of human cells.This review summarizes the latest progress from the establishment of iPSCs,the strategies for differentiating iPSCs into vascular cells,and the in vivo trans-plantation of these vascular derivatives.It also introduces the application of these technologies in disease modeling,drug screening,and regenerative medicine.Additionally,the application of high-tech tools,such as omics analysis and high-throughput sequencing,in this field is reviewed.

Non-enzymatic methods for isolation of stromal vascular fraction and adipose-derived stem cells:A systematic review

BACKGROUND Adipose-derived stem cells(ADSCs)and the stromal vascular fraction(SVF)have garnered substantial interest in regenerative medicine due to their potential to treat a wide range of conditions.Traditional enzymatic methods for isolating these cells face challenges such as high costs,lengthy processing time,and regulatory complexities.AIM This systematic review aimed to assess the efficacy and practicality of nonenzymatic,mechanical methods for isolating SVF and ADSCs,comparing these to conventional enzymatic approaches.METHODS Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines,a comprehensive literature search was conducted across multiple databases.Studies were selected based on inclusion criteria focused on non-enzymatic isolation methods for SVF and ADSCs from adipose tissue.The risk of bias was assessed,and a qualitative synthesis of findings was performed due to the methodological heterogeneity of the included studies.RESULTS Nineteen studies met the inclusion criteria,highlighting various mechanical techniques such as centrifugation,vortexing,and ultrasonic cavitation.The review identified significant variability in cell yield and viability,and the integrity of isolated cells across different non-enzymatic methods compared to enzymatic procedures.Despite some advantages of mechanical methods,including reduced processing time and avoidance of enzymatic reagents,the evidence suggests a need for optimization to match the cell quality and therapeutic efficacy achievable with enzymatic isolation.CONCLUSION Non-enzymatic,mechanical methods offer a promising alternative to enzymatic isolation of SVF and ADSCs,potentially simplifying the isolation process and reducing regulatory hurdles.However,further research is necessary to standardize these techniques and ensure consistent,high-quality cell yields for clinical applications.The development of efficient,safe,and reproducible non-enzymatic isolation methods could significantly advance the field of regenerative medicine.

Human pluripotent stem cell-derived kidney organoids:Current progress and challenges

Human pluripotent stem cell(hPSC)-derived kidney organoids share similarities with the fetal kidney.However,the current hPSC-derived kidney organoids have some limitations,including the inability to perform nephrogenesis and lack of a corticomedullary definition,uniform vascular system,and coordinated exit path-way for urinary filtrate.Therefore,further studies are required to produce hPSC-derived kidney organoids that accurately mimic human kidneys to facilitate research on kidney development,regeneration,disease modeling,and drug screening.In this review,we discussed recent advances in the generation of hPSC-derived kidney organoids,how these organoids contribute to the understanding of human kidney development and research in disease modeling.Additionally,the limitations,future research focus,and applications of hPSC-derived kidney organoids were highlighted.

Early expressions of hypoxia-inducible factor 1alpha and vascular endothelial growth factor increase the neuronal plasticity of activated endogenous neural stem cells after focal cerebral ischemia

Endogenous neural stem cells become ＂activated＂ after neuronal injury, but the activation sequence and fate of endogenous neural stem cells in focal cerebral ischemia model are little known. We evaluated the relationships between neural stem cells and hypoxia-inducible factor-1α and vascular endothelial growth factor expression in a photothromobotic rat stroke model using immunohistochemistry and western blot analysis. We also evaluated the chronological changes of neural stem cells by 5-bromo-2′-deoxyuridine（BrdU） incorporation. Hypoxia-inducible factor-1α expression was initially increased from 1 hour after ischemic injury, followed by vascular endothelial growth factor expression. Hypoxia-inducible factor-1α immunoreactivity was detected in the ipsilateral cortical neurons of the infarct core and peri-infarct area. Vascular endothelial growth factor immunoreactivity was detected in bilateral cortex, but ipsilateral cortex staining intensity and numbers were greater than the contralateral cortex. Vascular endothelial growth factor immunoreactive cells were easily found along the peri-infarct area 12 hours after focal cerebral ischemia. The expression of nestin increased throughout the microvasculature in the ischemic core and the peri-infarct area in all experimental rats after 24 hours of ischemic injury. Nestin immunoreactivity increased in the subventricular zone during 12 hours to 3 days, and prominently increased in the ipsilateral cortex between 3–7 days. Nestin-labeled cells showed dual differentiation with microvessels near the infarct core and reactive astrocytes in the peri-infarct area. BrdU-labeled cells were increased gradually from day 1 in the ipsilateral subventricular zone and cortex, and numerous BrdU-labeled cells were observed in the peri-infarct area and non-lesioned cortex at 3 days. BrdU-labeled cells rather than neurons, were mainly co-labeled with nestin and GFAP. Early expressions of hypoxia-inducible factor-1α and vascular endothelial growth factor after ischemia made up the microenvironment to increase the neuronal plasticity of activated endogenous neural stem cells. Moreover, neural precursor cells after large-scale cortical injury could be recruited from the cortex nearby infarct core and subventricular zone.

Transplantation of vascular endothelial growth factor-modified neural stem/progenitor cells promotes the recovery of neurological function following hypoxic-ischemic brain damage

Neural stem/progenitor cell （NSC） transplantation has been shown to effectively improve neurological function in rats with hypoxic-isch- emic brain damage. Vascular endothelial growth factor （VEGF） is a signaling protein that stimulates angiogenesis and improves neural regeneration. We hypothesized that transplantation of VEGF-transfected NSCs would alleviate hypoxic-ischemic brain damage in neo- natal rats. We produced and transfected a recombinant lentiviral vector containing the VEGF165gene into cultured NSCs. The transfected NSCs were transplanted into the left sensorimotor cortex of rats 3 days after hypoxic-ischemic brain damage. Compared with the NSCs group, VEGF mRNA and protein expression levels were increased in the transgene NSCs group, and learning and memory abilities were significantly improved at 30 days. Furthermore, histopathological changes were alleviated in these animals. Our findings indicate that transplantation of VEGF-transfected NSCs may facilitate the recovery of neurological function, and that its therapeutic effectiveness is better than that of unmodified NSCs.

Response of the sensorimotor cortex of cerebral palsy rats receiving transplantation of vascular endothelial growth factor 165-transfected neural stem cells

Neural stem cells are characterized by the ability to differentiate and stably express exogenous ge- nes. Vascular endothelial growth factor plays a role in protecting local blood vessels and neurons of newborn rats with hypoxic-ischemic encephalopathy. Transplantation of vascular endothelial growth factor-transfected neural stem cells may be neuroprotective in rats with cerebral palsy. In this study, 7-day-old Sprague-Dawley rats were divided into five groups： （1） sham operation （control）, （2） cerebral palsy model alone or with （3） phosphate-buffered saline, （4） vascular en- dothelial growth factor 165 ＋ neural stem cells, or （5） neural stem cells alone. The cerebral palsy model was established by ligating the left common carotid artery followed by exposure to hypox- ia. Phosphate-buffered saline, vascular endothelial growth factor ＋ neural stem cells, and neural stem cells alone were administered into the sensorimotor cortex using the stereotaxic instrument and microsyringe. After transplantation, the radial-arm water maze test and holding test were performed. Immunohistochemistry for vascular endothelial growth factor and histology using hematoxylin-eosin were performed on cerebral cortex. Results revealed that the number of vas- cular endothelial growth factor-positive cells in cerebral palsy rats transplanted with vascular endothelial growth factor-transfected neural stem cells was increased, the time for finding water and the finding repetitions were reduced, the holding time was prolonged, and the degree of cell degeneration or necrosis was reduced. These findings indicate that the transplantation of vascu- lar endothelial growth factor-transfected neural stem cells alleviates brain damage and cognitive deficits, and is neuroprotective in neonatal rats with hypoxia ischemic-mediated cerebral palsy.

The interaction of stem cells and vascularity in peripheral nerve regeneration

The degree of nerve regeneration after peripheral nerve injury can be altered by the microenvironment at the site of injury. Stem cells and vascularity are postulated to be a part of a complex pathway that enhances peripheral nerve regeneration;however, their interaction remains unexplored. This review aims to summarize current knowledge on this interaction, including various mechanisms through which trophic factors are promoted by stem cells and angiogenesis. Angiogenesis after nerve injury is stimulated by hypoxia, mediated by vascular endothelial growth factor, resulting in the growth of preexisting vessels into new areas. Modulation of distinct signaling pathways in stem cells can promote angiogenesis by the secretion of various angiogenic factors. Simultaneously, the importance of stem cells in peripheral nerve regeneration relies on their ability to promote myelin formation and their capacity to be influenced by the microenvironment to differentiate into Schwann-like cells. Stem cells can be acquired through various sources that correlate to their differentiation potential, including embryonic stem cells, neural stem cells, and mesenchymal stem cells. Each source of stem cells serves its particular differentiation potential and properties associated with the promotion of revascularization and nerve regeneration. Exosomes are a subtype of extracellular vesicles released from cell types and play an important role in cell-to-cell communication. Exosomes hold promise for future transplantation applications, as these vesicles contain fewer membrane-bound proteins, resulting in lower immunogenicity. This review presents pre-clinical and clinical studies that focus on selecting the ideal type of stem cell and optimizing stem cell delivery methods for potential translation to clinical practice. Future studies integrating stem cell-based therapies with the promotion of angiogenesis may elucidate the synergistic pathways and ultimately enhance nerve regeneration.

Therapeutic effects of dental pulp stem cells on vascular dementia in rat models

Dental pulp stem cells are a type of adult stem cells with strong proliferative ability and multi-differentiation potential. There are no studies on treatment of vascular dementia with dental pulp stem cells. In the present study, rat models of vascular dementia were established by two-vessel occlusion, and 30 days later, rats were injected with 2 × 10^(7) dental pulp stem cells via the tail vein. At 70 days after vascular dementia induction, dental pulp stem cells had migrated to the brain tissue of rat vascular dementia models and differentiated into neuronlike cells. At the same time, doublecortin, neurofilament 200, and Neu N m RNA and protein expression levels in the brain tissue were increased, and glial fibrillary acidic protein m RNA and protein expression levels were decreased. Behavioral testing also revealed that dental pulp stem cell transplantation improved the cognitive function of rat vascular dementia models. These findings suggest that dental pulp stem cell transplantation is effective in treating vascular dementia possibly through a paracrine mechanism. The study was approved by the Animal Ethics Committee of Harbin Medical University(approval No. KY2017-132) in 2017.

Effects of bone marrow-derived mesenchymal stemcells engraftment on vascular endothelial cell growthfactor in lung tissue and plasma at early stage of smoke inhalation injury

BACKGROUND： This study was undertaken to determine the effect of mesenchymal stem cells （MSCs） engraftment on vascular endothelial cell growth factor （VEGF） in lung tissue, plasma and extravascular lung water at early stage of smoke inhalation injury.METHODS： A rabbit smoke inhalation injury model was established using a home-made smoke inhalation injury generator, and rabbits were divided into two groups randomly： a control group （S group, n=32） and a MSCs treatment group （M group, n=32）. 10 ml PBS was injected via the ear marginal vein immediately at injury into the S group. Third generation MSCs with a concentration of 1×107/10 ml PBS were injected via the ear marginal vein immediately at injury into the M group. VEGF in peripheral blood and lung tissue were measured at 0 （baseline）, 2, 4 and 6 hours after injection respectively and analyzed. The right lungs of rabbits were taken to measure lung water mass fraction.RESULTS： In the lung tissue, VEGF decreased gradually in the S group （P〈0.05） and signi？ cantly decreased in the M group （P〈0.05）, but it increased more signi？ cantly than the values at the corresponding time points （P〈0.05）. In peripheral blood, VEGF increased gradually in the S group （P〈0.05） and markedly increased in the M group （P〈0.05）, but it decreased more signi？ cantly than the values at corresponding time points （P〈0.05）.CONCLUSION： MSCs engraftment to smoke inhalation injury could increase VEGF in lung tissue, decrease VEGF in plasma and reduce extravascular lung water, indicating its protective effect on smoke inhalation injury.

Overexpression of vascular endothelial growth factor enhances the neuroprotective effects of bone marrow mesenchymal stem cell transplantation in ischemic stroke

Although bone marrow mesenchymal stem cells(BMSCs)might have therapeutic potency in ischemic stroke,the benefits are limited.The current study investigated the effects of BMSCs engineered to overexpress vascular endothelial growth factor(VEGF)on behavioral defects in a rat model of transient cerebral ischemia,which was induced by middle cerebral artery occlusion.VEGF-BMSCs or control grafts were injected into the left striatum of the infarcted hemisphere 24 hours after stroke.We found that compared with the stroke-only group and the vehicle-and BMSCs-control groups,the VEGF-BMSCs treated animals displayed the largest benefits,as evidenced by attenuated behavioral defects and smaller infarct volume 7 days after stroke.Additionally,VEGF-BMSCs greatly inhibited destruction of the blood-brain barrier,increased the regeneration of blood vessels in the region of ischemic penumbra,and reducedneuronal degeneration surrounding the infarct core.Further mechanistic studies showed that among all transplant groups,VEGF-BMSCs transplantation induced the highest level of brain-derived neurotrophic factor.These results suggest that BMSCs transplantation with vascular endothelial growth factor has the potential to treat ischemic stroke with better results than are currently available.

Mechanoresponse of stem cells for vascular repair

Stem cells have shown great potential in vascular repair.Numerous evidence indicates that mechanical forces such as shear stress and cyclic strain can regulate the adhesion,proliferation,migration,and differentiation of stem cells via serious signaling pathways.The enrichment and differentiation of stem cells play an important role in the angiogenesis and maintenance of vascular homeostasis.In normal tissues,blood flow directly affects the microenvironment of vascular endothelial cells(ECs);in pathological status,the abnormal interactions between blood flow and vessels contribute to the injury of vessels.Next,the altered mechanical forces are transduced into cells by mechanosensors to trigger the reformation of vessels.This process occurs when signaling pathways related to EC differentiation are initiated.Hence,a deep understanding of the responses of stem cells to mechanical stresses and the underlying mechanisms involved in this process is essential for clinical translation.In this the review,we provide an overview of the role of stem cells in vascular repair,outline the performance of stem cells under the mechanical stress stimulation,and describe the related signaling pathways.

Vascularization and osteogenesis in ectopically implanted bone tissue-engineered constructs with endothelial and osteogenic differentiated adipose-derived stem cells

BACKGROUND A major problem in the healing of bone defects is insufficient or absent blood supply within the defect.To overcome this challenging problem,a plethora of approaches within bone tissue engineering have been developed recently.Bearing in mind that the interplay of various diffusible factors released by endothelial cells(ECs)and osteoblasts(OBs)have a pivotal role in bone growth and regeneration and that adjacent ECs and OBs also communicate directly through gap junctions,we set the focus on the simultaneous application of these cell types together with platelet-rich plasma(PRP)as a growth factor reservoir within ectopic bone tissue engineering constructs.AIM To vascularize and examine osteogenesis in bone tissue engineering constructs enriched with PRP and adipose-derived stem cells(ASCs)induced into ECs and OBs.METHODS ASCs isolated from adipose tissue,induced in vitro into ECs,OBs or just expanded were used for implant construction as followed:BPEO,endothelial and osteogenic differentiated ASCs with PRP and bone mineral matrix;BPUI,uninduced ASCs with PRP and bone mineral matrix;BC(control),only bone mineral matrix.At 1,2,4 and 8 wk after subcutaneous implantation in mice,implants were extracted and endothelial-related and bone-related gene expression were analyzed,while histological analyses were performed after 2 and 8 wk.RESULTS The percentage of vascularization was significantly higher in BC compared to BPUI and BPEO constructs 2 and 8 wk after implantation.BC had the lowest endothelial-related gene expression,weaker osteocalcin immunoexpression and Spp1 expression compared to BPUI and BPEO.Endothelial-related gene expression and osteocalcin immunoexpression were higher in BPUI compared to BC and BPEO.BPEO had a higher percentage of vascularization compared to BPUI and the highest CD31 immunoexpression among examined constructs.Except Vwf,endothelial-related gene expression in BPEO had a later onset and was upregulated and well-balanced during in vivo incubation that induced late onset of Spp1 expression and pronounced osteocalcin immunoexpression at 2 and 8 wk.Tissue regression was noticed in BPEO constructs after 8 wk.CONCLUSION Ectopically implanted BPEO constructs had a favorable impact on vascularization and osteogenesis,but tissue regression imposed the need for discovering a more optimal EC/OB ratio prior to considerations for clinical applications.

Refining adipose-derived stem cell isolation for optimal regenerative therapy

This article highlights the importance of optimizing the techniques used for isolating stromal vascular fraction cells from adipose tissue.Furthermore,by presenting key findings from the literature,it clarifies the effects of refined techniques on regenerative medicine and advocates for ongoing research and innovation to enhance therapeutic outcomes.

Mesenchymal stem cell-derived exosomes inhibit the VEGF-A expression in human retinal vascular endothelial cells induced by high glucose

AIM:To determine the effect of exosomes derived from human umbilical cord blood mesenchymal stem cells(hUCMSCs)on the expression of vascular endothelial growth factor A(VEGF-A)in human retinal vascular endothelial cells(HRECs).METHODS:Exosomes were isolated from hUCMSCs using cryogenic ultracentrifugation and characterized by transmission electron microscopy,Western blotting and nanoparticle tracking analysis.HRECs were randomly divided into a normal control group(group A),a high glucose model group(group B),a high glucose group with 25μg/mL(group C),50μg/mL(group D),and 100μg/mL exosomes(group E).Twenty-four hours after coculture,the cell proliferation rate was detected using flow cytometry,and the VEGF-A level was detected using immunofluorescence.After coculture 8,16,and 24h,the expression levels of VEGF-A in each group were detected using PCR and Western blots.RESULTS:The characteristic morphology(membrane structured vesicles)and size(diameter between 50 and 200 nm)were observed under transmission electron microscopy.The average diameter of 122.7 nm was discovered by nanoparticle tracking analysis(NTA).The exosomal markers CD9,CD63,and HSP70 were strongly detected.The proliferation rate of the cells in group B increased after 24h of coculture.Immunofluorescence analyses revealed that the upregulation of VEGF-A expression in HRECs stimulated by high glucose could be downregulated by cocultured hUCMSC-derived exosomes(F=39.03,P<0.01).The upregulation of VEGF-A protein(group C:F=7.96;group D:F=17.29;group E:F=11.89;8h:F=9.45;16h:F=12.86;24h:F=42.28,P<0.05)and mRNA(group C:F=4.137;group D:F=13.64;group E:F=22.19;8h:F=7.253;16h:F=16.98;24h:F=22.62,P<0.05)in HRECs stimulated by high glucose was downregulated by cocultured hUCMSC-derived exosomes(P<0.05).CONCLUSION:hUCMSC-derived exosomes downregulate VEGF-A expression in HRECs stimulated by high glucose in time and concentration dependent manner.

MicroRNA-146a Promotes Embryonic Stem Cell Differentiation towards Vascular Smooth Muscle Cells through Regulation of Kruppel-like Factor 4

Objective Vascular smooth muscle cell(VSMC)differentiation from stem cells is one source of the increasing number of VSMCs that are involved in vascular remodeling-related diseases such as hypertension,atherosclerosis,and restenosis.MicroRNA-146a(miR-146a)has been proven to be involved in cell proliferation,migration,and tumor metabolism.However,little is known about the functional role of miR-146a in VSMC differentiation from embryonic stem cells(ESCs).This study aimed to determine the role of miR-146a in VSMC differentiation from ESCs.Methods Mouse ESCs were differentiated into VSMCs,and the cell extracts were analyzed by Western blotting and RT-qPCR.In addition,luciferase reporter assays using ESCs transfected with miR-146a/mimic and plasmids were performed.Finally,C57BL/6J female mice were injected with mimic or miR-146a-overexpressing ESCs,and immunohistochemistry,Western blotting,and RT-qPCR assays were carried out on tissue samples from these mice.Results miR-146a was significantly upregulated during VSMC differentiation,accompanied with the VSMC-specific marker genes smooth muscle-alpha-actin(SMαA),smooth muscle 22(SM22),smooth muscle myosin heavy chain(SMMHC),and h1-calponin.Furthermore,overexpression of miR-146a enhanced the differentiation process in vitro and in vivo.Concurrently,the expression of Kruppel-like factor 4(KLF4),predicted as one of the top targets of miR-146a,was sharply decreased in miR-146a-overexpressing ESCs.Importantly,inhibiting KLF4 expression enhanced the VSMC-specific gene expression induced by miR-146a overexpression in differentiating ESCs.In addition,miR-146a upregulated the mRNA expression levels and transcriptional activity of VSMC differentiation-related transcription factors,including serum response factor(SRF)and myocyte enhancer factor 2c(MEF-2c).Conclusion Our data support that miR-146a promotes ESC-VSMC differentiation through regulating KLF4 and modulating the transcription factor activity of VSMCs.

Lentiviral-mediated vascular endothelial growth factor 165 gene transfer into neural stem cells promotes proliferation

We constructed a lentiviral vector carrying vascular endothelial growth factor 165, which was used to transfect neural stem cells. The transfection rate was approximately 50%, as determined by flow cytometry. Vascular endothelial growth factor protein was detected in neural stem cells and promoted proliferation.

Human umbilical cord mesenchymal stem cells derivedexosomes on VEGF-A in hypoxic-induced mice retinal astrocytes and mice model of retinopathy of prematurity

AIM:To observe the effect of human umbilical cord mesenchymal stem cells(hUCMSCs)secretions on the relevant factors in mouse retinal astrocytes,and to investigate the effect of hUCMSCs on the expression of vascular endothelial growth factor-A(VEGF-A)and to observe the therapeutic effect on the mouse model of retinopathy of prematurity(ROP).METHODS:Cultured hUCMSCs and extracted exosomes from them and then retinal astrocytes were divided into control group and hypoxia group.MTT assay,flow cytometry,reverse transcription-polymerase chain reaction(RT-PCR)and Western blot were used to detect related indicators.Possible mechanisms by which hUCMSCs exosomes affect VEGF-A expression in hypoxia-induced mouse retinal astrocytes were explored.At last,the efficacy of exosomes of UCMSCs in a mouse ROP model was explored.Graphpad6 was used to comprehensively process data information.RESULTS:The secretion was successfully extracted from the culture supernatant of hUCMSCs by gradient ultracentrifugation.Reactive oxygen species(ROS)and hypoxia inducible factor-1α(HIF-1α)of mice retinal astrocytes under different hypoxia time and the expression level of VEGF-A protein and VEGF-A mRNA increased,and the ROP cell model was established after 6h of hypoxia.The secretions of medium and high concentrations of hUCMSCs can reduce ROS and HIF-1α,the expression levels of VEGF-A protein and VEGF-A mRNA are statistically significant and concentration dependent.Compared with the ROP cell model group,the expression of phosphatidylinositol 3-kinase(PI3K)/protein kinase B(AKT)/mammalian target of rapamycin(mTOR)signal pathway related factors in the hUCMSCs exocrine group is significantly decreased.The intravitreal injection of the secretions of medium and high concentrations of hUCMSCs can reduce VEGF-A and HIF-1αin ROP model tissues.HE staining shows that the number of retinal neovascularization in ROP mice decreases with the increase of the dose of hUCMSCs secretion.CONCLUSION:In a hypoxia induced mouse retinal astrocyte model,hUCMSCs exosomes are found to effectively reduce the expression of HIF-1αand VEGF-A,which are positively correlated with the concentration of hUCMSCs exosomes.HUCMSCs exosomes can effectively reduce the number of retinal neovascularization and the expression of HIF-1αand VEGF-A proteins in ROP mice,and are positively correlated with drug dosage.Besides,they can reduce the related factors on the PI3K/AKT/mTOR signaling pathway.

Potential plausible role of Wharton’s jelly mesenchymal stem cells for diabetic bone regeneration

This letter addresses the review titled“Wharton’s jelly mesenchymal stem cells:Future regenerative medicine for clinical applications in mitigation of radiation injury”.The review highlights the regenerative potential of Wharton’s jelly mesenchymal stem cells(WJ-MSCs)and describes why WJ-MSCs will become one of the most probable stem cells for future regenerative medicine.The potential plausible role of WJ-MSCs for diabetic bone regeneration should be noticeable,which will provide a new strategy for improving bone regeneration under diabetic conditions.

Vascular endothelial growth factor/platelet-derived growth factor receptor pathway is involved in bone marrow mesenchymal stem cell differentiation and directional migration toward gliomas

BACKGROUND： Vascular endothelial growth factor （VEGF） induces bone marrow-derived mesenchymal stem cell （BMSC） differentiation into vascular endothelial-like cells and promotes BMSC migration toward gliomas. However, the molecular mechanisms by which VEGF induces BMSC differentiation and migration remain poorly understood. OBJECTIVE; To investigate the role of platelet-derived growth factor （PDGF） receptor （PDGFR） in BMSC differentiation and migration induced by VEGE DESIGN, TIME AND SETTING： A parallel, controlled, in vitro experiment was performed at the Molecular Neurobiology ＆ Neural Regeneration and Repairing Laboratory, Anhui Provincial Hospital of Anhui Medical University, China from June 2008 to March 2009. MATERIALS： U87 glioma cells were purchased from Shanghai Institutes for Biological Sciences; mouse anti-human PDGFR and VEGF receptor （VEGFR） monoclonal antibodies were purchased from Peprotech, USA. METHODS： Isolated BMSCs were precultured with neutralizing antibody for VEGFR-1, VEGFR-2, PDGFR-α, and PDGFR-β to block biological activity of related receptors, followed by induced differentiation with 50μg/L VEGF. BMSCs induced with 50μg/L VEGF alone served as the VEGF-induced group. The control group remained untreated. MAIN OUTCOME MEASURES： Cell surface markers were identified by flow cytometry; BMSC surface cytokine receptor expression was detected by reverse transcription-polymerase chain reaction; the Transwell model was used to observe cell migration. RESULTS： After blocking the PDGFR, VEGF did not induce BMSC cell surface marker CD-31 or von Willebrand factor （vWF） expression. However, inhibition with VEGF receptor blocking agents, VEGF induced BMSCs to express CD-31 and vWE Following inhibition of the PDGFR, the number of cells migrating through the polycarbonate membrane Transwell chamber was decreased, as well as the number of BMSCs migrating to glioma cells. However, through the use of VEGF receptor blocking agents, the number of migrating cells remained unchanged. VEGF preculture increased the number of BMSCs migrating to gliomas. CONCLUSION： VEGF interacts with PDGFRs on the BMSC surface to attract BMSC directional migration and induce BMSC differentiation. The VEGF/PDGFR pathway participates in BMSC directional migration to glioma. VEGF pretreatment increased efficiency of BMSC migration to glioma.

Neuron-specific enolase expression in a rat model of radiation-induced brain injury following vascular endothelial growth factor-modified neural stem cell transplantation

BACKGROUND： Previous studies have shown that transplantation of vascular endothelial growth factor （VEGF）-modified neural stem cells （NSC） provides better outcomes, compared with neural stem cells, in the treatment of brain damage. OBJECTIVE： To compare the effects of VEGF-modified NSC transplantation and NSC transplantation on radiation-induced brain injury, and to determine neuron-specific enolase （NSE） expression in the brain. DESIGN, TIME, AND SETTING： The randomized, controlled study was performed at the Linbaixin Experimental Center, Second Affiliated Hospital, Sun Yat-sen University, China from November 2007 to October 2008. MATERIALS： VEGF-modified C17.2 NSCs were supplied by Harvard Medical School, USA. Streptavidin-biotin-peroxidase-complex kit （Boster, China） and 5, 6-carboxyfluorescein diacetate succinimidyl ester （Fluka, USA） were used in this study. METHODS： A total of 84 Sprague Dawley rats were randomly assigned to a blank control group （n = 20）, model group （n = 20）, NSC group （n = 20）, and a VEGF-modified NSC group （n = 24）. Rat models of radiation-induced brain injury were established in the model, NSC, and VEGF-modified NSC groups. At 1 week following model induction, 10 pL （5 ×10^4 cells/μL） VEGF-modified NSCs or NSCs were respectively infused into the striatum and cerebral cortex of rats from the VEGF-modified NSC and NSC groups. A total of 10μL saline was injected into rats from the blank control and model groups. MAIN OUTCOME MEASURES： NSE expression in the brain was detected by immunohistochemistry following VEGF-modified NSC transplantation. RESULTS： NSE expression was significantly decreased in the brains of radiation-induced brain injury rats （P 〈 0.05）. The number of NSE-positive neurons significantly increased in the NSC and VEGF-modified NSC groups, compared with the model group （P 〈 0.05）. NSE expression significantly increased in the VEGF-modified NSC group, compared with the NSC group, at 6 weeks following transplantation （P 〈 0.05）. CONCLUSION： VEGF-modified NSC transplantation increased NSE expression in rats with radiation-induced brain injury, and the outcomes were superior to NSC transplantation.