Dissecting molecular mechanisms underlying ferroptosis in human umbilical cord mesenchymal stem cells:Role of cystathionineγ-lyase/hydrogen sulfide pathway

BACKGROUND Ferroptosis can induce low retention and engraftment after mesenchymal stem cell(MSC)delivery,which is considered a major challenge to the effectiveness of MSC-based pulmonary arterial hypertension(PAH)therapy.Interestingly,the cystathionineγ-lyase(CSE)/hydrogen sulfide(H_(2)S)pathway may contribute to mediating ferroptosis.However,the influence of the CSE/H_(2)S pathway on ferroptosis in human umbilical cord MSCs(HUCMSCs)remains unclear.AIM To clarify whether the effect of HUCMSCs on vascular remodelling in PAH mice is affected by CSE/H_(2)S pathway-mediated ferroptosis,and to investigate the functions of the CSE/H_(2)S pathway in ferroptosis in HUCMSCs and the underlying mechanisms.METHODS Erastin and ferrostatin-1(Fer-1)were used to induce and inhibit ferroptosis,respectively.HUCMSCs were transfected with a vector to overexpress or inhibit expression of CSE.A PAH mouse model was established using 4-wk-old male BALB/c nude mice under hypoxic conditions,and pulmonary pressure and vascular remodelling were measured.The survival of HUCMSCs after delivery was observed by in vivo bioluminescence imaging.Cell viability,iron accumulation,reactive oxygen species production,cystine uptake,and lipid peroxidation in HUCMSCs were tested.Ferroptosis-related proteins and S-sulfhydrated Kelchlike ECH-associating protein 1(Keap1)were detected by western blot analysis.RESULTS In vivo,CSE overexpression improved cell survival after erastin-treated HUCMSC delivery in mice with hypoxiainduced PAH.In vitro,CSE overexpression improved H_(2)S production and ferroptosis-related indexes,such as cell viability,iron level,reactive oxygen species production,cystine uptake,lipid peroxidation,mitochondrial membrane density,and ferroptosis-related protein expression,in erastin-treated HUCMSCs.In contrast,in vivo,CSE inhibition decreased cell survival after Fer-1-treated HUCMSC delivery and aggravated vascular remodelling in PAH mice.In vitro,CSE inhibition decreased H_(2)S levels and restored ferroptosis in Fer-1-treated HUCMSCs.Interestingly,upregulation of the CSE/H_(2)S pathway induced Keap1 S-sulfhydration,which contributed to the inhibition of ferroptosis.CONCLUSION Regulation of the CSE/H_(2)S pathway in HUCMSCs contributes to the inhibition of ferroptosis and improves the suppressive effect on vascular remodelling in mice with hypoxia-induced PAH.Moreover,the protective effect of the CSE/H_(2)S pathway against ferroptosis in HUCMSCs is mediated via S-sulfhydrated Keap1/nuclear factor erythroid 2-related factor 2 signalling.The present study may provide a novel therapeutic avenue for improving the protective capacity of transplanted MSCs in PAH.

Enhanced wound healing and hemostasis with exosome-loaded gelatin sponges from human umbilical cord mesenchymal stem cells

BACKGROUND Rapid wound healing remains a pressing clinical challenge,necessitating studies to hasten this process.A promising approach involves the utilization of human umbilical cord mesenchymal stem cells(hUC-MSCs)derived exosomes.The hypothesis of this study was that these exosomes,when loaded onto a gelatin sponge,a common hemostatic material,would enhance hemostasis and accelerate wound healing.AIM To investigate the hemostatic and wound healing efficacy of gelatin sponges loaded with hUC-MSCs-derived exosomes.METHODS Ultracentrifugation was used to extract exosomes from hUC-MSCs.Nanoparticle tracking analysis(NTA),transmission electron microscopy(TEM),and western blot techniques were used to validate the exosomes.In vitro experiments were performed using L929 cells to evaluate the cytotoxicity of the exosomes and their impact on cell growth and survival.New Zealand rabbits were used for skin irritation experiments to assess whether they caused adverse skin reactions.Hemolysis test was conducted using a 2%rabbit red blood cell suspension to detect whether they caused hemolysis.Moreover,in vivo experiments were carried out by implanting a gelatin sponge loaded with exosomes subcutaneously in Sprague-Dawley(SD)rats to perform biocompatibility tests.In addition,coagulation index test was conducted to evaluate their impact on blood coagulation.Meanwhile,SD rat liver defect hemostasis model and full-thickness skin defect model were used to study whether the gelatin sponge loaded with exosomes effectively stopped bleeding and promoted wound healing.RESULTS The NTA,TEM,and western blot experimental results confirmed that exosomes were successfully isolated from hUC-MSCs.The gelatin sponge loaded with exosomes did not exhibit significant cell toxicity,skin irritation,or hemolysis,and they demonstrated good compatibility in SD rats.Additionally,the effectiveness of the gelatin sponge loaded with exosomes in hemostasis and wound healing was validated.The results of the coagulation index experiment indicated that the gelatin sponge loaded with exosomes had significantly better coagulation effect compared to the regular gelatin sponge,and they showed excellent hemostatic performance in a liver defect hemostasis model.Finally,the full-thickness skin defect healing experiment results showed significant improvement in the healing process of wounds treated with the gelatin sponge loaded with exosomes compared to other groups.CONCLUSION Collectively,the gelatin sponge loaded with hUC-MSCs-derived exosomes is safe and efficacious for promoting hemostasis and accelerating wound healing,warranting further clinical application.

Effect of Human Umbilical Cord Mesenchymal Stem Cells on GRP78/ATF4 Pathway in Alzheimer s Disease Model Mice

[Objectives]To study the effect of human umbilical cord mesenchymal stem cells(hUC-MSCs)on GRP78/ATF4 pathway in APP/PS1 mice.[Methods]Twelve 6-month-old female APP/PS1 mice were randomly divided into model group(MOD,n=6)and human umbilical cord mesenchymal stem cell treatment group(MSC,n=6);six 6-month-old C57BL/6N mice were used as control group(CON,n=6).The mice in each group were treated with the fourth generation of human umbilical cord mesenchymal stem cells through tail vein.Four weeks later,the mice in each group were killed.The expression of GFP78 and ATF4 in the cortex of mice in each group was detected by Western blotting and real-time fluorescence quantitative PCR.[Results]The results of immunoblotting and real-time fluorescence quantitative PCR showed that the expression of GRP78 in MOD group was lower than that in CON group and the expression of ATF4 increased.The expression of GRP78 protein in MSC group was higher than that in MOD group,but the expression of ATF4 protein was lower.The results of real-time fluorescence quantitative PCR showed that the mRNA level of GRP78 decreased and the mRNA level of ATF4 increased in MOD group compared with CON group.The mRNA level of GRP78 in MSC group was higher than that in MOD group,while the mRNA level of ATF4 in MSC group was lower than that in MOD group.[Conclusions]Human umbilical cord mesenchymal stem cells can regulate the expression of GRP78/ATF4 pathway in APP/PSI mice,which may be related to the stress level of endoplasmic reticulum in the brain of APP/PS1 mice mediated by human umbilical cord mesenchymal stem cells.

Hypoxia and inflammatory factor preconditioning enhances the immunosuppressive properties of human umbilical cord mesenchymal stem cells

BACKGROUND Mesenchymal stem cells(MSCs)have great potential for the treatment of various immune diseases due to their unique immunomodulatory properties.However,MSCs exposed to the harsh inflammatory environment of damaged tissue after intravenous transplantation cannot exert their biological effects,and therefore,their therapeutic efficacy is reduced.In this challenging context,an in vitro preconditioning method is necessary for the development of MSC-based therapies with increased immunomodulatory capacity and transplantation efficacy.AIM To determine whether hypoxia and inflammatory factor preconditioning increases the immunosuppressive properties of MSCs without affecting their biological characteristics.METHODS Umbilical cord MSCs(UC-MSCs)were pretreated with hypoxia(2%O_(2))exposure and inflammatory factors(interleukin-1β,tumor necrosis factor-α,interferon-γ)for 24 h.Flow cytometry,polymerase chain reaction,enzyme-linked immunosorbent assay and other experimental methods were used to evaluate the biological characteristics of pretreated UC-MSCs and to determine whether pretreatment affected the immunosuppressive ability of UC-MSCs in coculture with immune cells.RESULTS Pretreatment with hypoxia and inflammatory factors caused UC-MSCs to be elongated but did not affect their viability,proliferation or size.In addition,pretreatment significantly decreased the expression of coagulationrelated tissue factors but did not affect the expression of other surface markers.Similarly,mitochondrial function and integrity were retained.Although pretreatment promoted UC-MSC apoptosis and senescence,it increased the expression of genes and proteins related to immune regulation.Pretreatment increased peripheral blood mononuclear cell and natural killer(NK)cell proliferation rates and inhibited NK cell-induced toxicity to varying degrees.CONCLUSION In summary,hypoxia and inflammatory factor preconditioning led to higher immunosuppressive effects of MSCs without damaging their biological characteristics.

Multiomics reveal human umbilical cord mesenchymal stem cells improving acute lung injury via the lung-gut axis

BACKGROUND Acute lung injury(ALI)and its final severe stage,acute respiratory distress syndrome,are associated with high morbidity and mortality rates in patients due to the lack of effective specific treatments.Gut microbiota homeostasis,including that in ALI,is important for human health.Evidence suggests that the gut microbiota improves lung injury through the lung-gut axis.Human umbilical cord mesenchymal cells(HUC-MSCs)have attractive prospects for ALI treatment.This study hypothesized that HUC-MSCs improve ALI via the lung-gut microflora.AIM To explore the effects of HUC-MSCs on lipopolysaccharide(LPS)-induced ALI in mice and the involvement of the lung-gut axis in this process.METHODS C57BL/6 mice were randomly divided into four groups(18 rats per group):Sham,sham+HUC-MSCs,LPS,and LPS+HUC-MSCs.ALI was induced in mice by intraperitoneal injections of LPS(10 mg/kg).After 6 h,mice were intervened with 0.5 mL phosphate buffered saline(PBS)containing 1×10^(6) HUC-MSCs by intraperitoneal injections.For the negative control,100 mL 0.9%NaCl and 0.5 mL PBS were used.Bronchoalveolar lavage fluid(BALF)was obtained from anesthetized mice,and their blood,lungs,ileum,and feces were obtained by an aseptic technique following CO_(2) euthanasia.Wright’s staining,enzyme-linked immunosorbent assay,hematoxylin-eosin staining,Evans blue dye leakage assay,immunohistochemistry,fluorescence in situ hybridization,western blot,16S rDNA sequencing,and non-targeted metabolomics were used to observe the effect of HUC-MSCs on ALI mice,and the involvement of the lung-gut axis in this process was explored.One-way analysis of variance with post-hoc Tukey’s test,independent-sample Student’s t-test,Wilcoxon rank-sum test,and Pearson correlation analysis were used for statistical analyses.RESULTS HUC-MSCs were observed to improve pulmonary edema and lung and ileal injury,and decrease mononuclear cell and neutrophil counts,protein concentrations in BALF and inflammatory cytokine levels in the serum,lung,and ileum of ALI mice.Especially,HUC-MSCs decreased Evans blue concentration and Toll-like receptor 4,myeloid differentiation factor 88,p-nuclear factor kappa-B(NF-κB)/NF-κB,and p-inhibitorαof NF-κB(p-IκBα)/IκBαexpression levels in the lung,and raised the pulmonary vascular endothelial-cadherin,zonula occludens-1(ZO-1),and occludin levels and ileal ZO-1,claudin-1,and occludin expression levels.HUC-MSCs improved gut and BALF microbial homeostases.The number of pathogenic bacteria decreased in the BALF of ALI mice treated with HUCMSCs.Concurrently,the abundances of Oscillospira and Coprococcus in the feces of HUS-MSC-treated ALI mice were significantly increased.In addition,Lactobacillus,Bacteroides,and unidentified_Rikenellaceae genera appeared in both feces and BALF.Moreover,this study performed metabolomic analysis on the lung tissue and identified five upregulated metabolites and 11 downregulated metabolites in the LPS+MSC group compared to the LPS group,which were related to the purine metabolism and the taste transduction signaling pathways.Therefore,an intrinsic link between lung metabolite levels and BALF flora homeostasis was established.CONCLUSION This study suggests that HUM-MSCs attenuate ALI by redefining the gut and lung microbiota.

Dose optimization of intrathecal administration of human umbilical cord mesenchymal stem cells for the treatment of subacute incomplete spinal cord injury

Human umbilical cord mesenchymal stem cells(hUC-MSCs)are a promising candidate for spinal cord injury(SCI)repair owing to their advantages of low immunogenicity and easy accessibility over other MSC sources.However,modest clinical efficacy hampered the progression of these cells to clinical translation.This discrepancy may be due to many variables,such as cell source,timing of implantation,route of administration,and relevant efficacious cell dose,which are critical factors that affect the efficacy of treatment of patients with SCI.Previously,we have evaluated the safety and efficacy of 4×10^(6) hUC-MSCs/kg in the treatment of subacute SCI by intrathecal implantation in rat models.To search for a more accurate dose range for clinical translation,we compared the effects of three different doses of hUC-MSCs-low(0.25×10^(6) cells/kg),medium(1×10^(6) cells/kg)and high(4×10^(6) cells/kg)-on subacute SCI repair through an elaborate combination of behavioral analyses,anatomical analyses,magnetic resonance imaging-diffusion tensor imaging(MRI-DTI),biotinylated dextran amine(BDA)tracing,electrophysiology,and quantification of mRNA levels of ion channels and neurotransmitter receptors.Our study demonstrated that the medium dose,but not the low dose,is as efficient as the high dose in producing the desired therapeutic outcomes.Furthermore,partial restoration of theγ-aminobutyric acid type A(GABAA)receptor expression by the effective doses indicates that GABAA receptors are possible candidates for therapeutic targeting of dormant relay pathways in injured spinal cord.Overall,this study revealed that intrathecal implantation of 1×10^(6) hUC-MSCs/kg is an alternative approach for treating subacute SCI.

Protective effects of human umbilical cord mesenchymal stem cells on retinal ganglion cells in mice with acute ocular hypertension

AIM:To observe the protective effect of human umbilical cord mesenchymal stem cells(huc MSCs)on retinal ganglion cel s(RGCs)injury in mice with acute ocular hypertension(AOH).METHODS:Fifty-six adult male C57 BL/6 mice were randomly divided into four groups:normal group,AOH group,huc MSCs group,normal saline(NS)group.Left eye of mice was induced by 90 mm Hg intraocular pressure for 1 h to establish AOH model.huc MSCs 1×105/μL,1μL or NS 1μL was injected into the vitreous body the next day.CMDil fluorescent dye was used to label the 3 rd generation of huc MSCs,for tracing the cells in the vitreous cavity of mice.Seven days after the model established,hematoxylin-eosin(HE)staining was used to observe the thickness of the inner retina layer in four groups.Numbers and loss rate of RGCs were evaluated by counting Brn-3 a positive cells stained by immunofluorescencein.RESULTS:On the 7 th day after AOH established,labeled huc MSCs were found in the vitreous cavity.HE staining showed that the thickness of retinal inner layer in AOH group was significantly lower than that in normal group and huc MSCs group(P<0.05),same as that in NS group(P>0.05).Compared with AOH group,the RGCs in normal group was significantly higher;RGCs number increased in huc MSCs group and the loss rate was lower(P<0.05).Injection of NS had no protective effect on RGCs.CONCLUSION:In AOH mouse model,vitreous injection of hucMSCs have shown a protection for RGCs.

Human umbilical cord mesenchymal stem cells as cell carriers in the treatment of gliomas: research status and prospects

Human umbilical cord mesenchymal stem cells(HuMSCs)have the multi-difFerentiation potential to differentiate into various types of cells without immune rejection.They are considered to be an ideal source of neural stem cells and also an ideal cell carrier for gene therapy.Because of the invasive growth of brain gliomas,most of them have no obvious boundaries with normal brain tissues.It is difficult to completely remove them by surgery and the remaining cells become the main source of tumor recurrence.In recent years,gene therapy has become a new method for the treatment of gliomas.The vector carrying the target gene is introduced into HuMSCs in a certain way to correct gene defects or play other roles.The differentiation potential of HuMSCs makes it an ideal source of nerve cells to play a greater role in gene therapy of glioma.Therefore,this article reviews the current status and prospects of HuMSCs as cell carriers in the treatment of glioma.

Influence of bone morphogenetic proteins-2 and strontium chloride on the human umbilical cord mesenchymal stem cells proliferation and osteogenic differentiation

Objective To study the effects of combination of bone morphogenetic protein-2 (BMP-2) and strontium chloride on proliferation and osteogenic differentiation of human umbilical cord mesenchymal stem cells(hUCM-SCs)in vitro culture.

Human umbilical cord mesenchymal stem cells to treat spinal cord injury in the early chronic phase: study protocol for a prospective, multicenter, randomized, placebo-controlled, single-blinded clinical trial

Human umbilical cord mesenchymal stem cells(hUC-MSCs)support revascularization,inhibition of inflammation,regulation of apoptosis,and promotion of the release of beneficial factors.Thus,they are regarded as a promising candidate for the treatment of intractable spinal cord injury(SCI).Clinical studies on patients with early chronic SCI(from 2 months to 1 year post-injury),which is clinically common,are rare;therefore,we will conduct a prospective,multicenter,randomized,placebo-controlled,single-blinded clinical trial at the Third Affiliated Hospital of Sun Yat-sen University,West China Hospital of Sichuan University,and Shanghai East Hospital,Tongji University School of Medicine,China.The trial plans to recruit 66 early chronic SCI patients.Eligible patients will undergo randomization at a 2:1 ratio to two arms:the observation group and the control group.Subjects in the observation group will receive four intrathecal transplantations of stem cells,with a dosage of 1×106/kg,at one calendar month intervals.Subjects in the control group will receive intrathecal administrations of 10 mL sterile normal saline in place of the stem cell transplantations.Clinical safety will be assessed by the analysis of adverse events and laboratory tests.The American Spinal Injury Association(ASIA)total score will be the primary efficacy endpoint,and the secondary efficacy outcomes will be the following:ASIA impairment scale,International Association of Neural Restoration-Spinal Cord Injury Functional Rating Scale,muscle tension,electromyogram,cortical motor and cortical sensory evoked potentials,residual urine volume,magnetic resonance imaging–diffusion tensor imaging,T cell subtypes in serum,neurotrophic factors and inflammatory factors in both serum and cerebrospinal fluid.All evaluations will be performed at 1,3,6,and 12 months following the final intrathecal administration.During the entire study procedure,all adverse events will be reported as soon as they are noted.This trial is designed to evaluate the clinical safety and efficacy of subarachnoid transplantation of hUC-MSCs to treat early chronic SCI.Moreover,it will establish whether cytotherapy can ameliorate local hostile microenvironments,promote tracking fiber regeneration,and strengthen spinal conduction ability,thus improving overall motor,sensory,and micturition/defecation function in patients with early chronic SCI.This study was approved by the Stem Cell Research Ethics Committee of the Third Affiliated Hospital of Sun Yat-sen University,China(approval No.[2018]-02)on March 30,2018,and was registered with ClinicalTrials.gov(registration No.NCT03521323)on April 12,2018.The revised trial protocol(protocol version 4.0)was approved by the Stem Cell Research Ethics Committee of the Third Affiliated Hospital of Sun Yat-sen University,China(approval No.[2019]-10)on February 25,2019,and released on ClinicalTrials.gov on April 29,2019.

Human umbilical cord mesenchymal stem cells promote peripheral nerve repair via paracrine mechanisms

Human umbilical cord-derived mesenchymal stem cells （hUCMSCs） represent a promising young-state stem cell source for cell-based therapy. hUCMSC transplantation into the transected sciatic nerve promotes axonal regeneration and functional recovery. To further clarify the para-crine effects of hUCMSCs on nerve regeneration, we performed human cytokine antibody array analysis, which revealed that hUCMSCs express 14 important neurotrophic factors. Enzyme-linked immunosorbent assay and immunohistochemistry showed that brain-derived neurotrophic factor, glial-derived neurotrophic factor, hepatocyte growth factor, neurotrophin-3, basic fibroblast growth factor, type I collagen, fibronectin and laminin were highly expressed. Treatment with hUCMSC-conditioned medium enhanced Schwann cell viability and proliferation, increased nerve growth factor and brain-derived neurotrophic factor expression in Schwann cells, and enhanced neurite growth from dorsal root ganglion explants. These ifndings suggest that paracrine action may be a key mechanism underlying the effects of hUCMSCs in peripheral nerve repair.

Human umbilical cord mesenchymal stem cells as treatment of adjuvant rheumatoid arthritis in a rat model

AIM:To investigate the effect of human umbilical cord stem cells,both mesenchymal and hematopoietic(CD34+),in the treatment of arthritis.METHODS:Mesenchymal stem cells(MSCs) and hematopoietic(CD34+) stem cells(HSC) were isolated from human umbilical cord blood obtained from the umbilical cord of healthy pregnant donors undergoing fullterm normal vaginal delivery.MSC,HSC,methotrexate(MTX) and sterile saline were injected intra-articularly into the rat hindpaw with complete freunds adjuvant(CFA) induced arthritis after the onset of disease(day 34),when arthritis had become well established(arthritis score ≥ 2).Arthritic indices were evaluated and the levels of interleukin(IL)-1,tumor necrosis factor(TNF)-α and interferon(IFN)-γ and anti-inflammatory cytokine IL-10 in serum were determined using enzyme-linked immunosorbent assay.Animals of all groups were sacrificed 34 d after beginning treatment,except positive control(PC) which was sacrificed at 10,21 and 34 d for microscopic observation of disease progression.We used hematoxylin,eosin and Masson's trichrome stains for histopathological examination of cartilage and synovium.RESULTS:The mean arthritis scores were similar in all groups at 12 and 34 d post immunization,with no statistical significant difference.Upon the injection of stem cells(hematopoietic and mesenchymal),the overall arthritis signs were significantly improved around 21 d after receiving the injection and totally disappeared at day 34 post treatment in MSC group.Mean hindpaw diameter(mm) in the MSC rats was about half that of the PC and MTX groups(P = 0.007 and P = 0.021,respectively) and 0.6 mm less than the HSC group(P = 0.047),as indicated by paw swelling.Associated with these findings,serum levels of TNF-α,IFN-γ and IL-1 decreased significantly in HSC and MSC groups compared to PC and MTX groups(P < 0.05),while the expression of IL-10 was increased.Histopathological examination with H and E stain revealed that the MTX treated group showed significant reduction of leucocytic infiltrate and hypertrophy of the synovial tissue with moderate obliteration of the joint cavity.Stem cells treated groups(both hematopoietic CD34+ and mesenchymal),showed significant reduction in leucocytic infiltrate and hypertrophy of the synovial tissue with mild obliteration of the joint cavity.With Masson's trichrome,stain sections from the PC group showed evidence of vascular edema of almost all vessels within the synovium in nearly all arthritic rats.Vacuoles were also visible in the outer vessel wall.The vessel became hemorrhagic and finally necrotic.In addition,there was extensive fibrosis completely obliterating the joint cavity.The mean color area percentage of collagen in this group was 0.324 ± 0.096,which was significantly increased when compared to the negative control group.The mean color area percentage of collagen in hematopoietic CD34+ and mesenchymal groups was 0.176 ± 0.0137 and 0.174 ± 0.0197 respectively,which showed a marked decrement compared to the PC group,denoting a mild increase in synovial tissue collagen fibers.CONCLUSION:MSC enhance the efficacy of CFAinduced arthritis treatment,most likely through the modulation of the expression of cytokines and amelioration of pathological changes in joints.

Differentiation of isolated human umbilical cord mesenchymal stem cells into neural stem cells

AIM：To investigate whether umbilical cord human mesenchymal stem cell（UC-MSC）was able to differentiate into neural stem cell and neuron.·METHODS：The umbilical cords were o btained from pregnant women with their written consent and the approval of the Clinic Ethnics Committee.UC-MSC were isolated by adherent culture in the medium contains 20%fetal bovine serum（FBS）,then they were maintained in the medium contain 10%FBS and induced to neural cells in neural differentiation medium.We investigated whether UC-MSC was able to differentiate into neural stem cell and neuron by using flow cytometry,reverse transcriptase-polymerase chain reaction（RT-PCR）and immunofluorescence（IF）analyzes.·R ESULTS：A substantial number of UC-MSC was harvested using the tissue explants adherent method at about 2wk.Flow cytometric study revealed that these cells expressed common markers of MSCs,such as CD105（SH2）,CD73（SH3）and CD90.After induction of differentiation of neural stem cells,the cells began to form clusters;RT-PCR and IF showed that the neuron specific enolase（NSE）and neurogenic differentiation 1-positive cells reached 87.3%±14.7%and 72.6%±11.8%,respectively.Cells showed neuronal cell differentiation after induced,including neuron-like protrusions,plump cell body,obviously and stronger refraction.RT-PCR and IF analysis showed that microtubule-associated protein 2（MAP2）and nuclear factor-M-positive cells reached 43.1%±10.3%and 69.4%±19.5%,respectively.·CONCLUSION：Human umbilical cord derived MSCs can be cultured and proliferated and differentiate into neural stem cells,which may be a valuable source for cell therapy of neurodegenerative eye diseases.

Experimental treatment of radiation pneumonitis with human umbilical cord mesenchymal stem cells

Objective:To evaluate of the curative effect of human umbilical cord mesenchymal stem cells(hUC-MSCs)on rat acute radiation pneumonitis.Methods:Fourty rats were randomly divided into control group,radiation group,stem cell prevention group,stem cell treatment group and prednisone treatment group.All rats except those in the control group were radiated with X ray to establish the acute radiation pneumonitis damage model.The hUC-MSCs cultured in vitro was administrated to the rats of the prevention group via tail vein(1×10~6 cells/kg BW)24 h before the radiation,while the same administration was performed in the rats of the treatment group 24 h after the radiation.After 24 h post the radiation,the rats in tbe radiation group were given 0.4 mL physiological saline,and those in the prednisone group were given 1 mg/kg prednisone.All rats were,observed and executed 72 h after the radiation to defect lung histological changes.Results:After the administration of hUC-MSCs,the survival status of the rats in the prevention group and treatment group was obviously better than that in the control group.As shown by the histological staining,the morphology,proliferation activity aad bronchial state of lung tissues were better in the prevention group and treatment group than in the control group.Conclusion:The hUC-MSCs have definite therapeutic effects on acute radiation pneumonitis in rats.

An experimental study of preventing and treating acute radioactive enteritis with human umbilical cord mesenchymal stem cells

Objective:To test the curative effect of human umbilical cord-derived mesenchymal stem cells on rat acute radioactive enteritis and thus in provide clinical therapeutic basis for radiation sickness.Methods:Human umbilical cord-derived mesenchymal stem cells were cultivated in vitro and the model of acute radioactive enteritis of rats was established.Then,the umbilical cord mesenchymal stem cells were injected into the rats via tail vein.Visual and histopathiological changes of the experimental rats were observed.Results:After the injection,the rats in the prevention group and treatment group had remarkably better survival status than those in the control group.The histological observations revealed that the former also had better intestinal mucosa structure,more regenerative cells and stronger proliferation activity than the latter.Conclusions:Human umbilical cord-derived mesenchymal stem cells have a definite therapeutic effect on acute radioactive enteritis in rats.

Ability of human umbilical cord mesenchymal stem cells to repair chemotherapy-induced premature ovarian failure

BACKGROUND Premature ovarian insufficiency(POI)and premature ovarian failure(POF)have become one of the major problems threatening women of childbearing age.Studies have shown that stem cells transplanted from bone marrow,umbilical cord,peripheral blood and amniotic fluid can migrate and proliferate to the ovary,promote ovarian function repair,increase the number of follicles and granulosa cells at all levels of ovary,improve endocrine function,and can differentiate into oocytes in specific ovarian environment to restore fertility to some extent.AIM To study the ability of human umbilical cord mesenchymal stem cells(hUCMSCs)to repair ovarian injury after chemotherapy.METHODS A total of 110 female BALB/c mice(aged 7-8 wk old)with body masses of 16.0-20.0 g were selected.The mice were fed until 12 wk of age,and cyclophosphamide was administered by intraperitoneal injection for 14 consecutive days to induce premature ovarian failure in mice.Seventy-five mice with estrous cycle disorder were screened and randomly divided into 3 groups according to their body weight:model group,positive control group and hUCMSC group,and each group had 25 mice.Another 25 mice were used as negative controls.The mice in the hUCMSC group were injected with hUCMSCs in the tail vein,and the mice in the positive control group were given an oestradiol valerate solution and a medroxyprogesterone acetate solution in the tail vein.On the 1^st,15^th,30^th,45^th,and 60^th days after intravenous administration,vaginal smears were made to monitor the estrous cycles of the mice.The ovaries were weighed,and pathological sections were made to observe the morphology of the follicles;blood samples were collected to monitor the concentration of sex hormones(oestradiol and follicle-stimulating hormone).RESULTS The estrous cycles of the model group mice were disrupted throughout the experiment.Mice in the hUCMSC group and the positive control group resumed normal estrous cycles.The ovarian weight of the model group mice continued to decline.The ovarian weight of the hUCMSC group mice and the positive control group mice decreased first and then gradually increased,and the ovarian weight of the hUCMSC group mice was heavier than that of the positive control group mice.The difference was statistically significant(P<0.05).Compared with the negative control group,the model group experienced a decrease in oestradiol and an increase in follicle-stimulating hormone,and the difference was statistically significant(P<0.05).Compared with the model group,the hUCMSC and positive control groups experienced a slight increase in oestradiol and a decrease in follicle-stimulating hormone;the difference was statistically significant(P<0.05).The pathological examination revealed that the mouse ovaries from the model group were atrophied,the volume was reduced,the cortical and medullary structures were disordered,the number of follicles at all stages was significantly reduced,the number of atretic follicles increased,the number of primordial follicles and corpus luteum significantly decreased,and the corpus luteum had an irregular shape.Compared with those of the model group,the lesions of the hUCMSC and positive control groups significantly improved.CONCLUSION hUCMSCs can repair ovarian tissue damaged by chemotherapy to a certain extent,can improve the degree of apoptosis in ovarian tissue,and can improve the endocrine function of mouse ovaries.

Human umbilical cord mesenchymal stem cells ameliorate liver fibrosis in vitro and in vivo: From biological characteristics to therapeutic mechanisms

Liver fibrosis is a wound-healing response to chronic injuries, characterized by the excessive accumulation of extracellular matrix or scar tissue within the liver;in addition, its formation is associated with multiple cytokines as well as several cell types and a variety of signaling pathways. When liver fibrosis is not well controlled, it can progress to liver cirrhosis, but it is reversible in principle. Thus far, no efficient therapy is available for treatment of liver fibrosis. Although liver transplantation is the preferred strategy, there are many challenges remaining in this approach, such as shortage of donor organs, immunological rejection, and surgical complications. Hence, there is a great need for an alternative therapeutic strategy. Currently, mesenchymal stem cell (MSC) therapy is considered a promising therapeutic strategy for the treatment of liver fibrosis;advantageously, the characteristics of MSCs are continuous self-renewal, proliferation, multipotent differentiation, and immunomodulatory activities. The human umbilical cord-derived (hUC)-MSCs possess not only the common attributes of MSCs but also more stable biological characteristics, relatively easy accessibility, abundant source, and no ethical issues (e.g., bone marrow being the adult source), making hUC-MSCs a good choice for treatment of liver fibrosis. In this review, we summarize the biological characteristics of hUC-MSCs and their paracrine effects, exerted by secretion of various cytokines, which ultimately promote liver repair through several signaling pathways. Additionally, we discuss the capacity of hUC-MSCs to differentiate into hepatocyte-like cells for compensating the function of existing hepatocytes, which may aid in amelioration of liver fibrosis. Finally, we discuss the current status of the research field and its future prospects.

Migration capacity of human umbilical cord mesenchymal stem cells towards glioma in vivo

High-grade glioma is the most common malignant primary brain tumor in adults. The poor prognosis of glioma, combined with a resistance tQ currently available treatments, necessitates the develop- ment of more effective tumor-selective therapies. Stem cell-based therapies are emerging as novel cell-based delivery vehicle for therapeutic agents. In the present study, we successfully isolated human umbilical cord mesenchymal stem cells by expiant culture. The human umbilical cord mes- enchymal stem cells were adherent to plastic surfaces, expressed specific surface phenotypes of mesenchymal stem cells as demonstrated by flow cytometry, and possessed multi-differentiation potentials in permissive induction media in vitro. Furthermore, human umbilical cord mesenchymal stem cells demonstrated excellent glioma-specific targeting capacity in established rat glioma models after intratumoral injection or contralateral ventricular administration in vivo. The excellent glioma-specific targeting ability and extensive intratumoral distribution of human umbilical cord mesenchymal stem cells indicate that they may serve as a novel cellular vehicle for delivering therapeutic molecules in glioma therapy.

Exosomes Derived from Human Umbilical Cord Mesenchymal Stem Cells Enhance the Osteoblastic Differentiation of Periodontal Ligament Stem Cells Under High Glucose Conditions Through the PI3K/AKT Signaling Pathway

Objective High glucose(HG)can influence the osteogenic differentiation ability of periodontal ligament stem cells(PDLSCs).Human umbilical cord mesenchymal stem cell-derived exosomes(hUCMSC-exo)have broad application prospects in tissue healing.The current study aimed to explore whether hUCMSC-exo could promote the osteogenic differentiation of hPDLSCs under HG conditions and the underlying mechanism.Methods We used a 30 mmol/L glucose concentration to simulate HG conditions.CCK-8 assay was performed to evaluate the effect of hUCMSC-exo on the proliferation of hPDLSCs.Alkaline phosphatase(ALP)staining,ALP activity,and qRT-PCR were performed to evaluate the pro-osteogenic effect of hUCMSC-exo on hPDLSCs.Western blot analysis was conducted to evaluate the underlying mechanism.Results The results of the CCK-8 assay,ALP staining,ALP activity,and qRT-PCR assay showed that hUCMSC-exo significantly promoted cell proliferation and osteogenic differentiation in a dosedependent manner.The Western blot results revealed that hUCMSC-exo significantly increased the levels of p-PI3K and p-AKT in cells,and the effect was inhibited by LY294002(PI3K inhibitor)or MK2206(AKT inhibitor),respectively.Moreover,the increases in osteogenic indicators induced by hUCMSC-exo were significantly suppressed by LY294002 and MK2206.Conclusion hUCMSC-exo promote the osteogenic differentiation of hPDLSCs under HG conditions through the PI3K/AKT signaling pathway.

Human amnion tissue injected with human umbilical cord mesenchymal stem cells repairs damaged sciatic nerves in rats

Human umbilical cord mesenchymal stem cells,incorporated into an amnion carrier tubes,were assessed for nerve regeneration potential in a rat nerve defect model.Damaged nerves were exposed to human amnion carriers containing either human umbilical cord mesenchymal stem cell （cell transplantation group）or saline（control group）.At 8,12,16 and 20 weeks after cell implantation,the sciatic functional index was higher in the cell transplantation group compared with the control group.Furthermore,electrophysiological examination showed that threshold stimulus and maximum stimulus intensity gradually decreased while compound action potential amplitude gradually increased.Hematoxylin-eosin staining showed that regenerating nerve fibers were arranged in nerve tracts in the cell transplantation group and connective tissue between nerve tracts and amnion tissue reduced over time.Gastrocnemius muscle cell diameter,wet weight and restoration ratio were increased.These data indicate that transplanted human umbilical cord mesenchymal stem cells,using the amnion tube connection method,promote restoration of damaged sciatic nerves in rats.