Therapeutic utility of human umbilical cord-derived mesenchymal stem cells-based approaches in pulmonary diseases:Recent advancements and prospects

Pulmonary diseases across all ages threaten millions of people and have emerged as one of the major public health issues worldwide.For diverse disease con-ditions,the currently available approaches are focused on alleviating clinical symptoms and delaying disease progression but have not shown significant therapeutic effects in patients with lung diseases.Human umbilical cord-derived mesenchymal stem cells(UC-MSCs)isolated from the human UC have the capacity for self-renewal and multilineage differentiation.Moreover,in recent years,these cells have been demonstrated to have unique advantages in the treatment of lung diseases.We searched the Public Clinical Trial Database and found 55 clinical trials involving UC-MSC therapy for pulmonary diseases,including coronavirus disease 2019,acute respiratory distress syndrome,bron-chopulmonary dysplasia,chronic obstructive pulmonary disease,and pulmonary fibrosis.In this review,we summarize the characteristics of these registered clinical trials and relevant published results and explore in depth the challenges and opportunitiesfaced in clinical application.Moreover,the underlying mole-cular mechanisms involved in UC-MSC-based therapy for pulmonary diseases are also analyzed in depth.In brief,this comprehensive review and detailed analysis of these clinical trials can be expected to provide a scientific reference for future large-scale clinical application.

Expansion of human umbilical cord derived mesenchymal stem cells in regenerative medicine

BACKGROUND Stem cells are undifferentiated cells that possess the potential for self-renewal with the capacity to differentiate into multiple lineages.In humans,their limited numbers pose a challenge in fulfilling the necessary demands for the regeneration and repair of damaged tissues or organs.Studies suggested that mesenchymal stem cells(MSCs),necessary for repair and regeneration via transplantation,require doses ranging from 10 to 400 million cells.Furthermore,the limited expansion of MSCs restricts their therapeutic application.AIM To optimize a novel protocol to achieve qualitative and quantitative expansion of MSCs to reach the targeted number of cells for cellular transplantation and minimize the limitations in stem cell therapy protocols.METHODS Human umbilical cord(hUC)tissue derived MSCs were obtained and re-cultured.These cultured cells were subjected to the following evaluation pro-cedures:Immunophenotyping,immunocytochemical staining,trilineage differentiation,population doubling time and number,gene expression markers for proliferation,cell cycle progression,senescence-associatedβ-galactosidase assay,human telomerase reverse transcriptase(hTERT)expression,mycoplasma,cytomegalovirus and endotoxin detection.RESULTS Analysis of pluripotent gene markers Oct4,Sox2,and Nanog in recultured hUC-MSC revealed no significant differences.The immunophenotypic markers CD90,CD73,CD105,CD44,vimentin,CD29,Stro-1,and Lin28 were positively expressed by these recultured expanded MSCs,and were found negative for CD34,CD11b,CD19,CD45,and HLA-DR.The recultured hUC-MSC population continued to expand through passage 15.Proliferative gene expression of Pax6,BMP2,and TGFb1 showed no significant variation between recultured hUC-MSC groups.Nevertheless,a significant increase(P<0.001)in the mitotic phase of the cell cycle was observed in recultured hUC-MSCs.Cellular senescence markers(hTERT expression andβ-galactosidase activity)did not show any negative effect on recultured hUC-MSCs.Additionally,quality control assessments consistently confirmed the absence of mycoplasma,cytomegalovirus,and endotoxin contamination.CONCLUSION This study proposes the development of a novel protocol for efficiently expanding stem cell population.This would address the growing demand for larger stem cell doses needed for cellular transplantation and will significantly improve the feasibility of stem cell based therapies.

Umbilical cord mesenchymal stem cell exosomes alleviate necrotizing enterocolitis in neonatal mice by regulating intestinal epithelial cells autophagy

BACKGROUND Necrotizing enterocolitis(NEC)is a severe gastrointestinal disease that affects premature infants.Although mounting evidence supports the therapeutic effect of exosomes on NEC,the underlying mechanisms remain unclear.AIM To investigate the mechanisms underlying the regulation of inflammatory response and intestinal barrier function by umbilical cord mesenchymal stem cell(UCMSCs)exosomes,as well as their potential in alleviating NEC in neonatal mice.METHODS NEC was induced in 5-d-old C57BL/6 pups through hypoxia and gavage feeding of formula containing lipopolysaccharide(LPS),after which the mice received human UCMSC exosomes(hUCMSC-exos).The control mice were allowed to breastfeed with their dams.Ileal tissues were collected from the mice and analyzed by histopathology and immunoblotting.Colon tissues were collected from NEC neonates and analyzed by immunofluorescence.Molecular biology and cell culture approaches were employed to study the related mechanisms in intestinal epithelial cells.RESULTS We found that autophagy is overactivated in intestinal epithelial cells during NEC,resulting in reduced expression of tight junction proteins and an increased inflammatory response.The ability of hUCMSC-exos to ameliorate NEC in a mouse model was dependent on decreased intestinal autophagy.We also showed that hUCMSC-exos alleviate the inflammatory response and increase migration ability in intestinal epithelial cells induced by LPS.CONCLUSION These results contribute to a better understanding of the protective mechanisms of hUCMSC-exos against NEC and provide a new theoretical and experimental foundation for NEC treatment.These findings also enhance our understanding of the role of the autophagy mechanism in NEC,offering potential avenues for identifying new therapeutic targets.

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.

Transplantation of mesenchymal stem cells from human umbilical cord versus human umbilical cord blood for peripheral nerve regeneration

BACKGROUND： Mesenchymal stem cells （MSCs） appear to be a good alternative to Schwann cells in the treatment of peripheral nerve injury. Fetal stem cells, like umbilical cord blood （UCB） and umbilical cord （UC） stem cells, have several advantages over adult stem cells. OBJECTIVE： To assess the effects of UC-derived MSCs （UCMSCs） and UCB-derived MSCs （UCBMSCs） in repair of sciatic nerve defects. DESIGN, TIME AND SETTING： A randomized controlled animal experiment was performed at the laboratory of Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital, from July to December 2009. MATERIALS： UCMSCs were provided by the Research Institute of Biotechnology, Dongguk University. UCBMSCs were provided by the Laboratory of Stem Cells and Tumor Biology, College of Veterinary Medicine, Seoul National University. Dulbecco＇s modified Eagle＇s medium （DMEM） was purchased from Gibco-BRL, USA. METHODS： Seven-week-old Sprague-Dawley rats were randomly and evenly divided into three groups： DMEM, UCBMSCs, and UCMSCs. A 10-mm defect in the left sciatic nerve was constructed in all rats. DMEM （15 μL） containing 1×10^6 UCBMSCs or UCMSCs was injected into the gap between nerve stumps, with the surrounding epineurium as a natural conduit. For the DMEM group, simple DMEM was injected. MAIN OUTCOME MEASURES： At 7 weeks after sciatic nerve dissection, dorsal root ganglia neurons were labeled by fluorogold retrograde labeling. At 8 weeks, electrophysiology and histomorphometry were performed. At 2, 4, 6, and 8 weeks after surgery, sciatic nerve function was evaluated using gait analysis. RESULTS： The UCBMSCs group and the UCMSCs group exhibited similar sciatic nerve function and electrophysiological indices, which were better than the DMEM group, as measured by gait analysis （P 〈 0.05）. Fluorogold retrograde labeling of sciatic nerve revealed that the UCBMSCs group demonstrated a higher number of labeled neurons; however, the differences were not significant. Histomorphometric indices were similar in the UCBMSCs and UCMSCs groups, and total axon counts, particularly axon density （P 〈 0.05）, were significantly greater in the UCBMSCs and UCMSCs groups than in the DMEM group. CONCLUSION： Transplanting either UCBMSCs or UCMSCs into axotomized sciatic nerves could accelerate and promote sciatic nerve regeneration over 8 weeks. Both treatments had similar effects on nerve regeneration.

Mesenchymal stem cells derived from human placenta suppress allogeneic umbilical cord blood lymphocyte proliferation

Human placenta-derived mononuclear cells （MNC） were isolated by a Percoll density gradient and cultured in mesenchymal stem cell （MSC） maintenance medium. The homogenous layer of adherent cells exhibited a typical fibroblastlike morphology, a large expansive potential, and cell cycle characteristics including a subset of quiescent cells. In vitro differentiation assays showed the tripotential differentiation capacity of these cells toward adipogenic, osteogenic and chondrogenic lineages. Flow cytometry analyses and immunocytochemistry stain showed that placental MSC was a homogeneous cell population devoid of hematopoietic cells, which uniformly expressed CD29, CD44, CD73, CD105, CD166, laminin, fibronectin and vimentin while being negative for expression of CD31, CD34, CD45 and m-smooth muscle actin. Most importantly, immuno-phenotypic analyses demonstrated that these cells expressed class Ⅰ major histocompatibility complex （MHC-I）, but they did not express MHC-Ⅱ molecules. Additionally these cells could suppress umbilical cord blood （UCB） lymphocytes proliferation induced by cellular or nonspecific mitogenic stimuli. This strongly implies that they may have potential application in allograft transplantation. Since placenta and UCB are homogeneous, the MSC derived from human placenta can be transplanted combined with hematopoietic stem cells （HSC） from UCB to reduce the potential graft-versus-host disease （GVHD） in recipients.

Stem cell transplantation for treatment of cerebral ischemia in rats Effects of human umbilical cord blood stem cells and human neural stem cells

BACKGROUND： Exogenous neural stem cell transplantation promotes neural regeneration. However, various types of stem cells transplantation outcomes remain controversial. OBJECTIVE： To explore distribution, proliferation and differentiation of human neural stem cells （hNSCs） and human umbilical cord blood stem cells （hUCBSCs） following transplantation in ischemic brain tissue of rats, and to compare therapeutic outcomes between hNSCs and hUCBSCs. DESIGN, TIME AND SETTING： Randomized controlled animal studies were performed at the Experimental Animal Center of Nanjing Medical University and Central Laboratory of Second Affiliated Hospital of Nanjing Medical University of China from September 2008 to April 2009. MATERIALS： hNSCs were harvested from brain tissue of 10 13 week old fetuses following spontaneous abortion, and hUCBSCs were collected from umbilical cord blood of full-term newborns at the Second Affiliated Hospital of Nanjing Medical University of China. hNSCs and hUCBSCs were labeled by 5-bromodeoxyuridine （BrdU） prior to transplantation. METHODS： Rat models of cerebral ischemia were established by the suture method. A total of 60 healthy male Sprague Dawley rats aged 7-9 weeks were randomly assigned to hNSC transplantation, hUCBSC transplantation and control groups. The rat models in the hNSC transplantation, hUCBSC transplantation and control groups were infused with hNSC suspension, hUCBSC suspension and saline via the caudal vein, respectively. MAIN OUTCOME MEASURES： The distribution, proliferation and differentiation of hNSCs and hUCBSCs in ischemic brain tissue were observed using immunohistochemical methods. Neurological function in rats was assessed using the neurological severity score. RESULTS： The number of BrdU-positive cells was significantly greater in the hNSC transplantation group compared with hUCBSC transplantation group at 14 days following transplantation （P 〈 0.05） The number of BrdU-positive cells reached a peak at 28 days following transplantation. Nestin-positive, glial fibrillary acidic protein-positive, cyclic nucleotide 3＇ phosphohydrolase-positive and neuron specific enolase-positive cells were visible following transplantation. No significant difference was determined in the constituent ratio of various cells between hNSC and hUCBSC transplantation groups （P 〉 0.05）. The neurological severity score was significantly decreased in rats at 21 days following transplantation （P 〈 0.05）. No significant difference was detected in neurological severity score between hNSC and hUCBSC transplantation groups at various time points （P 〉 0.05）. CONCLUSION： The transplanted hNSCs and hUCBSCs can migrate into ischemic brain tissue, proliferate and differentiate into neuron-like, astrocyte-like and oligodendrocyte-like cells, and improve neurological function in rats with cerebral ischemia.

Differentiation of human umbilical cord blood stem cells into hepatocytes in vivo and in vitro

AIM： To study the condition and potentiality of human umbilical cord blood stem cells （HUCBSC） to differentiate into hepatocytes in vivo or in vitro. METHODS： In a cell culture study of human umbilical cord blood stem cell （HUCBSC） differentiation, human umbilical cord blood mononuclear cells （HUCBMNC） were separated by density gradient centrifugation. Fibroblast growth factor （FGF） and hepatocyte growth factor （HGF） and the supernatant of fetal liver were added in the inducing groups. Only FGF was added in the control group. The expansion and differentiation of HUCBMNC in each group were observed. Human alpha fetoprotein （AFP） and albumin （ALB） were detected by immunohistochemistry. In the animal experiments, the survival SD rats with acute hepatic injury after carbon tetrachloride （CCL4） injection 48 h were randomly divided into three groups. The rats in group A were treated with human umbilical cord blood serum. The rats in group B were treated with HUCBMNC transplantation. The rats in group C were treated with HUCBMNC transplantation followed by intraperitoneal cyclophosphamide for 7 d. The rats were killed at different time points after the treatment and the liver tissue was histopathologically studied and human AFP and ALB detected by immunohistochemistry. The human X inactive-specific transcript gene fragment in the liver tissue was amplified by PCR to find human DNA. RESULTS： The results of cell culture showed that adherent cells were stained negative for AFP or ALB in control group. However, the adherent cells in the inducing groups stained positive for AFP or ALB. The result of animal experiment showed that no human AFP or ALB positive cells present in the liver tissue of group A （control group）. However, many human AFP or ALB positive cells were scattered around sinus hepaUcus and the central veins of hepatic Iobules and in the portal area in group B and group C after one month. The fragment of human X chromagene could be detected in the liver tissue of groups B and C, but not in group A.CONCLUSION： Under certain conditions HUCBSC can differentiate into liver cells in vivo and in vitro.

Brain-derived neurotrophic factor induces neuron-like cellular differentiation of mesenchymal stem cells derived from human umbilical cord blood cells in vitro

Human umbilical cord blood was collected from full-term deliveries scheduled for cesarean section. Mononuclear cells were isolated, amplified and induced as mesenchymal stem cells. Isolated mesenchymal stem cells tested positive for the marker CD29, CD44 and CD105 and negative for typical hematopoietic and endothelial markers. Following treatment with neural induction medium containing brain-derived neurotrophic factor for 7 days, the adherent cells exhibited neuron-like cellular morphology. Immunohistochemical staining and reverse transcription-PCR revealed that the induced mesenchymal stem cells expressed the markers for neuron-specific enolase and neurofilament. The results demonstrated that human umbilical cord blood-derived mesenchymal stem cells can differentiate into neuron-like cells induced by brain-derived neurotrophic factor in vitro.

Transplantation of human umbilical cord blood mesenchymal stem cells to treat a rat model of traumatic brain injury

In the present study, human umbilical cord blood mesenchymal stem cells were injected into a rat model of traumatic brain injury via the tail vein. Results showed that 5-bromodeoxyuridine-labeled cells aggregated around the injury site, surviving up to 4 weeks post-transplantation. In addition, transplantation-related death did not occur, and neurological functions significantly improved. Histological detection revealed attenuated pathological injury in rat brain tissues following human umbilical cord blood mesenchymal stem cell transplantation. In addition, the number of apoptotic cells decreased. Immunohistochemistry and in situ hybridization showed increased expression of brain-derived neurotrophic factor, nerve growth factor, basic fibroblast growth factor, and vascular endothelial growth factor, along with increased microvessel density in surrounding areas of brain injury. Results demonstrated migration of transplanted human umbilical cord blood mesenchymal stem cells into the lesioned boundary zone of rats, as well as increased angiogenesis and expression of related neurotrophic factors in the lesioned boundary zone.

Human umbilical cord blood-derived mesenchymal stem cells promote regeneration of crush-injured rat sciatic nerves

Several studies have demonstrated that human umbilical cord blood-derived mesenchymal stem cells can promote neural regeneration following brain injury. However, the therapeutic effects of human umbilical cord blood-derived mesenchymal stem cells in guiding peripheral nerve regeneration remain poorly understood. This study was designed to investigate the effects of human umbilical cord blood-derived mesenchymal stem cells on neural regeneration using a rat sciatic nerve crush injury model. Human umbilical cord blood-derived mesenchymal stem cells （1 ~ 106） or a PBS control were injected into the crush-injured segment of the sciatic nerve. Four weeks after cell injection, brain-derived neurotrophic factor and tyrosine kinase receptor B mRNA expression at the lesion site was increased in comparison to control. Furthermore, sciatic function index, Fluoro Gold-labeled neuron counts and axon density were also significantly increased when compared with control. Our results indicate that human umbilical cord blood-derived mesenchvmal stem cells promote the functinnal r~.RcJv^rv nf P.n I^h-inillr^4 ~r^i~tit, n^r~e

Vein transplantation using human umbilical cord blood stem cells in the treatment of stroke sequela

BACKGROUND: Transplanted mononuclear cell (MNC) of umbilical blood can survive in central nervous system (CNS) of host through blood brain barrier, differentiate into nerve cells, migrate to damaged site and integrate morphological structure and function with nerve cells of host so as to improve deficiencies of sensatory function, motor function and cognitive function and influence on stroke sequela. OBJECTIVE: To observe the vein transplantation of human umbilical cord blood stem cells (HUCBSC) for improving neurological function, limb function and activity of daily living of patients with stroke and evaluate the reliability. DESIGN: Self-controlled study. SETTING: Department of Neurosurgery, the Second People's Hospital of Zhengzhou City; Red-crossed Blood Center of Henan Province; Department of Neurosurgery, the Fist Affiliated Hospital of Zhengzhou University. PARTICIPANTS: A total of 10 patients with stroke sequela were selected from Department of Cerebral Surgery, the Second People's Hospital of Zhengzhou City from April to December 2005. There were 9 males and 1 female aged from 35 to 75 years with the mean age of 56 years. All of them were diagnosed with CT and MRI examination and coincidence with diagnostic criteria of stroke established by the Fourth National Academic Meeting for Cerebrovascular Disease. All patients provided informed consent. METHODS: 80-140 mL umbilical blood of term birth of newborn was selected hermetically and maintained in sterile plastic bag. And then, the blood was centrifugated at the speed of 1 500 r/min for 30 minutes at 22 ℃ in order to separate MNC, i.e., HUCBSC. In addition, after final diagnosis during hospitalization, stroke patients were perfused with HUCBSC through superficial vein of back of the hand. Each patient was averagely perfused with 6 portions of HUCBSC (cellular numbers ≥ 1×108/portion) and the interval between each portion was 1-7 days with the mean interval of 4 days. MAIN OUTCOME MEASURES: ① Neurological function of stroke patients was evaluated with neurological function deficiency (NFD) before treatment and at 3 months after treatment. The scale includes consciousness, level fix function, facial paralysis, language, muscle force of upper limbs, muscle force of lower limb and step function. The total scores ranged from 0 to 45; meanwhile, the lower the scores were, the better the neurological function was. ② Motor function of injured limbs was evaluated with Fugl-Meyer Assessment (FMA), including motor function of upper limbs, motor function of lower limbs, balance ability, sensory function and motion of joint. The total scores ranged from 0 to 226; meanwhile, the higher the scores were, the better the motor function of limbs was. ③ Activities of daily living (ADL) was evaluated with Barthel Index (BI), including having meals, taking a bath, dressing oneself, putting on clothes, walking in balance and stair activity. The total scores ranged from 0 to 100; meanwhile, the higher the scores were, the stronger the ADL was. RESULTS: A total of 10 patients were involved in the final analysis. After treatment, NFD of stroke patients was (10.9±5.09) points, which was lower than that before treatment [(25.4±6.09) points, t =8.213, P < 0.01]. In addition, after treatment, FMA and BI of stroke patients were (80.9±25.00) points and (81.1±15.93) points, respectively, which were higher than those before treatment [(31.9±21.85) points, (36.2±19.41) points, t =13.024, 13.670, P < 0.01]. Immuno-suppressive drugs were not used during the whole therapeutic procedure; moreover, immunological rejection and allergic reaction were not observed during the same period. CONCLUSION: Transplanting HUCBSC through superficial vein of back of the hand is regarded as a simple and safe method for the treatment of stroke sequela.

Functional recovery and microenvironmental alterations in a rat model of spinal cord injury following human umbilical cord blood-derived mesenchymal stem cells transplantation

BACKGROUND： Transplantation of human umbilical cord blood-derived mesenchymal stem cells （MSCs） has been shown to benefit spinal cord injury （SCI） repair. However, mechanisms of microenvironmental regulation during differentiation of transplanted MSCs remain poorly understood. OBJECTIVE： To observe changes in nerve growth factor （NGF）, brain-derived neurotrophic factor （BDNF）, and interleukin-8 （IL-8） expression following transplantation of human umbilical cord-derived MSCs, and to explore the association between microenvironment and neural functional recovery following MSCs transplantation. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Department of Orthopedics, First Affiliated Hospital of Soochow University from April 2005 to March 2007. MATERIALS： Human cord blood samples were provided by the Department of Gynecology and Obstetrics, First Affiliated Hospital of Soochow University. Written informed consent was obtained. METHODS： A total of 62 Wister rats were randomly assigned to control （n = 18）, model （n = 22, SCI ＋ PBS）, and transplantation （n = 22, SCI ＋ MSCs） groups. The rat SCI model was established using the weight compression method. MSCs were isolated from human umbilical cord blood and cultured in vitro for several passages. 5-bromodeoxyuridine （BrdU）-Iabeled MSCs （24 hours before injection） were intravascularly transplanted. MAIN OUTCOME MEASURES： The rats were evaluated using the Basso, Beattie and Bresnahan （BBB） locomotor score and inclined plane tests. Transplanted cells were analyzed following immunohistochemistry. Enzyme-linked immunosorbant assay was performed to determine NGF, BDNF, and IL-8 levels prior to and after cell transplantation. RESULTS： A large number of BrdU-positive MSCs were observed in the SCI region of the transplantation group, and MSCs were evenly distributed in injured spinal cord tissue 1 week after transplantation. BBB score and inclined plane test results revealed significant functional improvement in the transplantation group compared to the model group （P 〈 0.05）, which was maintained for 2-3 weeks. Compared to the model group, NGF and BDNF levels were significantly increased in the injured region following MSCs transplantation at 3 weeks （P 〈 0.05）, but IL-8 levels remained unchanged （P 〉 0.05）. CONCLUSION： MSCs transplantation increased NGF and BDNF expression in injured spinal cord tissue. MSCs could promote neurological function recovery in SCI rats by upregulating NGF expression and improving regional microenvironments.

Prospects for the therapeutic development of umbilical cord bloodderived mesenchymal stem cells

Umbilical cord blood(UCB)is a primitive and abundant source of mesenchymal stem cells(MSCs).UCB-derived MSCs have a broad and efficient therapeutic capacity to treat various diseases and disorders.Despite the high latent selfrenewal and differentiation capacity of these cells,the safety,efficacy,and yield of MSCs expanded for ex vivo clinical applications remains a concern.However,immunomodulatory effects have emerged in various disease models,exhibiting specific mechanisms of action,such as cell migration and homing,angiogenesis,anti-apoptosis,proliferation,anti-cancer,anti-fibrosis,anti-inflammation and tissue regeneration.Herein,we review the current literature pertaining to the UCB-derived MSC application as potential treatment strategies,and discuss the concerns regarding the safety and mass production issues in future applications.

Human umbilical cord blood stem cells and brainderived neurotrophic factor for optic nerve injury: a biomechanical evaluation

Treatment for optic nerve injury by brain-derived neurotrophic factor or the transplantation of human umbilical cord blood stem cells has gained progress, but analysis by biomechanical indicators is rare. Rabbit models of optic nerve injury were established by a clamp. At 7 days after injury, the vitreous body received a one-time injection of 50 μg brain-derived neurotrophic factor or 1 × 10^6 human umbilical cord blood stem cells. After 30 days, the maximum load, maximum stress, maximum strain, elastic limit load, elastic limit stress, and elastic limit strain had clearly improved in rabbit models of optical nerve injury after treatment with brain-derived neurotrophic factor or human umbilical cord blood stem cells. The damage to the ultrastructure of the optic nerve had also been reduced. These findings suggest that human umbilical cord blood stem cells and brain-derived neurotrophic factor effectively repair the injured optical nerve, improve biomechanical properties, and contribute to the recovery after injury.

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

BACKGROUND High tibial osteotomy(HTO)is a well-established method for the treatment of medial compartment osteoarthritis of the knee with varus deformity.However,HTO alone cannot adequately repair the arthritic joint,necessitating cartilage regeneration therapy.Cartilage regeneration procedures with concomitant HTO are used to improve the clinical outcome in patients with varus deformity.AIM To evaluate cartilage regeneration after implantation of allogenic human umbilical cord blood-derived mesenchymal stem cells(hUCB-MSCs)with concomitant HTO.METHODS Data for patients who underwent implantation of hUCB-MSCs with concomitant HTO were evaluated.The patients included in this study were over 40 years old,had a varus deformity of more than 5°,and a full-thickness International Cartilage Repair Society(ICRS)grade IV articular cartilage lesion of more than 4 cm2 in the medial compartment of the knee.All patients underwent second-look arthroscopy during hardware removal.Cartilage regeneration was evaluated macroscopically using the ICRS grading system in second-look arthroscopy.We also assessed the effects of patient characteristics,such as trochlear lesions,age,and lesion size,using patient medical records.RESULTS A total of 125 patients were included in the study,with an average age of 58.3±6.8 years(range:43-74 years old);95(76%)were female and 30(24%)were male.The average hip-knee-ankle(HKA)angle for measuring varus deformity was 7.6°±2.4°(range:5.0-14.2°).In second-look arthroscopy,the status of medial femoral condyle(MFC)cartilage was as follows:73(58.4%)patients with ICRS grade I,37(29.6%)with ICRS grade II,and 15(12%)with ICRS grade III.No patients were staged with ICRS grade IV.Additionally,the scores[except International Knee Documentation Committee(IKDC)at 1 year]of the ICRS grade I group improved more significantly than those of the ICRS grade II and III groups.CONCLUSION Implantation of hUCB-MSCs with concomitant HTO is an effective treatment for patients with medial compartment osteoarthritis and varus deformity.Regeneration of cartilage improves the clinical outcomes for the patients.

Human umbilical cord blood-derived stem cells and brain-derived neurotrophic factor protect injured optic nerve:viscoelasticity characterization

The optic nerve is a viscoelastic solid-like biomaterial.Its normal stress relaxation and creep properties enable the nerve to resist constant strain and protect it from injury.We hypothesized that stress relaxation and creep properties of the optic nerve change after injury.Moreover,human brain-derived neurotrophic factor or umbilical cord blood-derived stem cells may restore these changes to normal.To validate this hypothesis,a rabbit model of optic nerve injury was established using a clamp approach.At 7 days after injury,the vitreous body received a one-time injection of 50 μg human brain-derived neurotrophic factor or 1 × 106 human umbilical cord blood-derived stem cells.At 30 days after injury,stress relaxation and creep properties of the optic nerve that received treatment had recovered greatly,with pathological changes in the injured optic nerve also noticeably improved.These results suggest that human brain-derived neurotrophic factor or umbilical cord blood-derived stem cell intervention promotes viscoelasticity recovery of injured optic nerves,and thereby contributes to nerve recovery.

Umbilical cord blood mesenchymal stem cells protect amyloid-β42 neurotoxicity via paracrine

AIM:To understand the neuroprotective mechanism of human umbilical cord blood-derived mesenchymal stem cells(hUCB-MSCs) against amyloid-β42(Aβ42) exposed rat primary neurons.METHODS:To evaluate the neuroprotective effect of hUCB-MSCs,the cells were co-cultured with Aβ42-exposed rat primary neuronal cells in a Transwell apparatus.To assess the involvement of soluble fac-tors released from hUCB-MSCs in neuroprotection,an antibody-based array using co-cultured media was conducted.The neuroprotective roles of the identified hUCB-MSC proteins was assessed by treating recombi-nant proteins or specific small interfering RNAs(siRNAs) for each candidate protein in a co-culture system.RESULTS:The hUCB-MSCs secreted elevated levels ofdecorin and progranulin when co-cultured with rat pri-mary neuronal cells exposed to Aβ42.Treatment with recombinant decorin and progranulin protected from Aβ42-neurotoxicity in vitro.In addition,siRNA-mediat-ed knock-down of decorin and progranulin production in hUCB-MSCs reduced the anti-apoptotic effects of hUCB-MSC in the co-culture system.CONCLUSION:Decorin and progranulin may be involved in anti-apoptotic activity of hUCB-MSCs exposed to Aβ42.

Repair of a large patellar cartilage defect using human umbilical cord blood-derived mesenchymal stem cells:A case report

BACKGROUND Patellar dislocation may cause cartilage defects of various sizes.Large defects commonly require surgical treatment;however,conventional treatments are problematic.CASE SUMMARY A 15-year-old male with a large patellar cartilage defect due to patellar dislocation was treated via human umbilical cord blood-derived mesenchymal stem cell(hUCB-MSC)implantation.To our knowledge,this is the first report of this treatment for this purpose.The patient recovered well as indicated by good visual analog scale,International Knee Documentation Committee and McMaster Universities Osteoarthritis Index scores.Magnetic resonance imaging showed cartilage regeneration 18 mo postoperatively.CONCLUSION Umbilical cord blood-derived hUCB-MSCs may be a useful treatment option for the repair of large patellar cartilage defects.

Human umbilical cord blood mesenchymal stem cells conditioned media inhibits hypoxia-induced apoptosis in H9c2 cells by activation of the survival protein Akt

This work aimed to study the beneficial role of human umbilical cord blood-derived mesenchymal stem cellconditioned medium(MSC-CM)in hypoxia-induced apoptosis in H9c2 cardiomyoblasts,in which the serine/heroine kinases(Akt)pathway would be involved.For this,CM was collected by culturing MSCs in serum-free DMEM medium for 24 h,and paracrine factors were analyzed by protein chip.H9c2 cells were divided into the following groups:control group,hypoxia group,MSC-CM intervention group(CM group),MSC-CM+Akt phosphorylation inhibitor(LY294002)group(LY group).Apoptosis of the H9c2 cells was tested with chromatin dye Hoechst 33342 and FITC-conjugated Annexin V apoptosis detection kit by flow cytometer after a hypoxia/serum deprivation(H/SD)for 24 h.The apoptosis-related proteins were evaluated by Western blot.MSC-CM displayed significantly elevated levels of growth factors,anti-inflammatory,and anti-apoptosis cytokines.On Hoechst 33342 apoptosis staining,the H9c2 cell morphology displayed a lower proportion of apoptosis in the CM group than those in the hypoxia group,while apoptosis was increased in LY group.Flow cytometer analysis revealed the apoptosis ratio in the CM group was lower than the hypoxia group(12.34±2.00%vs.21.73±2.58%,p<0.05),while the LY group was significantly higher(22.54±3.89%).Active caspase-3 expression was increased in hypoxia group than control group(p<0.05),but decreased in CM group(p<0.01).Umbilical cord blood-derived mesenchymal stem cell-conditioned media secrete multiple paracrine factors that are able to inhibit hypoxia-induced H9c2 cardiomyoblasts apoptosis,and in which the activation of Akt phosphorylation is involved to achieve the protective effect.