The effect of neuropeptides on proliferation of rat bone marrow mesenchymal stem cells

Objective To investigate the effects and mechanism of calcitonin gene-related peptide(CGRP)and substance P (SP) on proliferation of rat bone marrow mesenchymal stem cells.Methods The rBMSCs were isolated using whole bone marrow

Mechanisms of action of neuropeptide Y on stem cells and its potential applications in orthopaedic disorders

Musculoskeletal disorders are the leading causes of disability and result in reduced quality of life.The neuro-osteogenic network is one of the most promising fields in orthopaedic research.Neuropeptide Y(NPY)system has been reported to be involved in the regulations of bone metabolism and homeostasis,which also provide feedback to the central NPY system via NPY receptors.Currently,potential roles of peripheral NPY in bone metabolism remain unclear.Growing evidence suggests that NPY can regulate biological actions of bone marrow mesenchymal stem cells,hematopoietic stem cells,endothelial cells,and chondrocytes via a local autocrine or paracrine manner by different NPY receptors.The regulative activities of NPY may be achieved through the plasticity of NPY receptors,and interactions among the targeted cells as well.In general,NPY can influence proliferation,apoptosis,differentiation,migration,mobilization,and cytokine secretion of different types of cells,and play crucial roles in the development of bone delayed/non-union,osteoporosis,and osteoarthritis.Further basic research should clarify detailed mechanisms of action of NPY on stem cells,and clinical investigations are also necessary to comprehensively evaluate potential applications of NPY and its receptor-targeted drugs in management of musculoskeletal disorders.

Mechanotransduction in subchondral bone microenvironment and targeted interventions for osteoarthritis

Osteoarthritis(OA)is a progressive degenerative joint sickness related with mechanics,obesity,ageing,etc.,mainly characterized by cartilage degeneration,subchondral bone damage and synovium inflammation.Coordinated mechanical absorption and conduction of the joint play significant roles in the prevalence and development of OA.Subchondral bone is generally considered a load-burdening tissue where mechanosensitive cells are resident,including osteocytes,osteoblast lineage cells,and osteoclast lineage cells(especially less concerned in mechanical studies).Mechano-signaling imbalances affect complicated cellular events and disorders of subchondral bone homeostasis.This paper will focus on the significance of mechanical force as the pathogenesis,involvement of various mechanical force patterns in mechanosensitive cells,and mechanobiology research of loading devices in vitro and in vivo,which are further discussed.Additionally,various mechanosensing structures(e.g.,transient receptor potential channels,gap junctions,primary cilia,podosome-associated complexes,extracellular vesicles)and mechanotransduction signaling pathways(e.g.,Ca^(2+) signaling,Wnt/β-catenin,RhoA GTPase,focal adhesion kinase,cotranscriptional activators YAP/TAZ)in mechanosensitive bone cells.Finally,we highlight potential targets for improving mechanoprotection in the treatment of OA.These advances furnish an integration of mechanical regulation of subchondral bone homeostasis,as well as OA therapeutic approaches by modulating mechanical homeostasis.

A multifunctional neuromodulation platform utilizing Schwann cell-derived exosomes orchestrates bone microenvironment via immunomodulation, angiogenesis and osteogenesis

Recent evidence highlights multifaceted biological needs to recapitulate the bone microenvironment for bone regeneration.Neurotization has great potential for realizing multi-system modulations in bone tissue engineering(BTE).However,a neural strategy involving all the key bone repair steps temporally has not yet been reported.In this study,we reported the neural tissue engineering hydrogel-encapsulated Schwann cell-derived exosomes(SC Exo).This sustained-release SC Exo system prominently enhanced bone regeneration by promoting innervation,immunoregulation,vascularization,and osteogenesis in vivo.Moreover,the in vitro results further confirmed that this system significantly induced M2 polarization of macrophages,tube formation of HUVECs,and BMSCs osteogenic differentiation.Furthermore,BMSCs osteogenesis was promoted by upregulating the TGF-β1/SMAD2/3 signaling pathway.In summary,a novel cell-free and easily prepared SC Exo neural engineering was successfully developed to promote bone regeneration by orchestrating the entire bone healing microenvironment,which may provide a new strategy for tissue engineering and clinical treatment of bone defects.

Interactions between cancer cells and bone microenvironment promote bone metastasis in prostate cancer

Bone metastasis is the leading cause of death in prostate cancer patients,for which there is currently no effective treatment.Since the bone microenvironment plays an important role in this process,attentions have been directed to the interactions between cancer cells and the bone microenvironment,including osteoclasts,osteoblasts,and bone stromal cells.Here,we explained the mechanism of interactions between prostate cancer cells and metastasis-associated cells within the bone microenvironment and further discussed the recent advances in targeted therapy of prostate cancer bone metastasis.This review also summarized the effects of bone microenvironment on prostate cancer metastasis and the related mechanisms,and provides insights for future prostate cancer metastasis studies.

Functionalize d 3D-printe d porous titanium scaffold induces in situ vascularized bone regeneration by orchestrating bone microenvironment

Titanium(Ti)and its alloys have been extensively explored for treating load-bearing bone defects.How-ever,high-stress shielding,weak osteogenic activity,and insufficient vascularization remain key chal-lenges for the long-term clinical outcomes of Ti-based implants.Herein,inspired by structural and func-tional cues of bone regeneration,a silicon-doped nano-hydroxyapatite(nSiHA)/titanium dioxide(TiO_(2))composite coating with a hierarchical micro/nano-network structure is constructed on the surface of a 3D-printed porous Ti scaffold via a combined strategy of acid-alkali(AA)treatment and electrochemi-cal deposition technique,which not only endows the scaffold with excellent osteoinduction ability but can also effectively immobilize and release vascular endothelial growth factor(VEGF).The results of the in vitro cell experiments show that the functionalized Ti scaffold significantly promotes osteogenesis in bone marrow mesenchymal stem cells(BMSCs)and angiogenesis in human umbilical vein endothelial cells(HUVECs)by activating the extracellular signal-regulated protein kinase(ERK)and HIF-1αsignaling pathways.After being implanted into a rat femoral condyle defect model,the functionalized Ti scaffold can induce in situ vascularized bone regeneration by orchestrating the two coupled processes of angio-genesis and osteogenesis.These findings indicate that the functionalized Ti scaffold has great potential in bone tissue regeneration and is a promising candidate for load-bearing bone defect repair.

Osteoimmunology in bone malignancies:a symphony with evil

Bone marrow is pivotal for normal hematopoiesis and immune responses,yet it is often compromised by malig-nancies.The bone microenvironment(BME),composed of bone and immune cells,maintains skeletal integrity and blood production.The emergence of primary or metastatic tumors in the skeletal system results in severe complications and contributes significantly to cancer-related mortality.These tumors set offa series of interac-tions among cancer,bone,and immune cells,and disrupt the BME locally or distantly.However,the drivers,participants,and underlying molecules of these interactions are not fully understood.This review explores the crosstalk between bone metabolism and immune responses,synthesizing current knowledge on the intersection of cancer and osteoimmune biology.It outlines how bone marrow immune cells can either facilitate or hinder tumor progression by interacting with bone cells and pinpoints the molecules responsible for immunosuppression within bone tumors.Moreover,it discusses how primary tumors remotely alter the BME,leading to systemic immune suppression in cancer patients.This knowledge provides critical rationales for emerging immunotherapies in the treatment of bone-related tumors.Taken together,by summarizing the intricate relationship between tumor cells and the BME,this review aims to deepen the understanding of the diversity,complexity,and dynamics at play during bone tumor progression.Ultimately,it highlights the potential of targeting bone-tumor interactions to correct aberrant immune functions,thereby inhibiting tumor growth and metastasis.

Bone microenvironment regulative hydrogels with ROS scavenging and prolonged oxygen-generating for enhancing bone repair

Large bone defects resulting from fractures and disease are a major clinical challenge,being often unable to heal spontaneously by the body’s repair mechanisms.Lines of evidence have shown that hypoxia-induced overproduction of ROS in bone defect region has a major impact on delaying bone regeneration.However,replenishing excess oxygen in a short time cause high oxygen tension that affect the activity of osteoblast precursor cells.Therefore,reasonably restoring the hypoxic condition of bone microenvironment is essential for facilitating bone repair.Herein,we designed ROS scavenging and responsive prolonged oxygen-generating hydrogels(CPP-L/GelMA)as a“bone microenvironment regulative hydrogel”to reverse the hypoxic microenvironment in bone defects region.CPP-L/GelMA hydrogels comprises an antioxidant enzyme catalase(CAT)and ROS-responsive oxygen-releasing nanoparticles(PFC@PLGA/PPS)co-loaded liposome(CCP-L)and GelMA hydrogels.Under hypoxic condition,CPP-L/GelMA can release CAT for degrading hydrogen peroxide to generate oxygen and be triggered by superfluous ROS to continuously release the oxygen for more than 2 weeks.The prolonged oxygen enriched microenvironment generated by CPP-L/GelMA hydrogel significantly enhanced angiogenesis and osteogenesis while inhibited osteoclastogenesis.Finally,CPP-L/GelMA showed excellent bone regeneration effect in a mice skull defect model through the Nrf2-BMAL1-autophagy pathway.Hence,CPP-L/GelMA,as a bone microenvironment regulative hydrogel for bone tissue respiration,can effectively scavenge ROS and provide prolonged oxygen supply according to the demand in bone defect region,possessing of great clinical therapeutic potential.

Bone marrow microenvironment: The guardian of leukemia stem cells

Bone marrow microenvironment (BMM) is the main sanctuary of leukemic stem cells (LSCs) and protects these cells against conventional therapies. However, it may open up an opportunity to target LSCs by breaking the close connection between LSCs and the BMM. The elimination of LSCs is of high importance, since they follow cancer stem cell theory as a part of this population. Based on cancer stem cell theory, a cell with stem cell-like features stands at the apex of the hierarchy and produces a heterogeneous population and governs the disease. Secretion of cytokines, chemokines, and extracellular vesicles, whether through autocrine or paracrine mechanisms by activation of downstream signaling pathways in LSCs, favors their persistence and makes the BMM less hospitable for normal stem cells. While all details about the interactions of the BMM and LSCs remain to be elucidated, some clinical trials have been designed to limit these reciprocal interactions to cure leukemia more effectively. In this review, we focus on chronic myeloid leukemia and acute myeloid leukemia LSCs and their milieu in the bone marrow, how to segregate them from the normal compartment, and finally the possible ways to eliminate these cells.

Pretreatment with antioxidants prevent bone injury by improving bone marrow microenvironment for stem cells

Irradiation induces bone injury by generating free radicals that adversely affect the microenvironment for Mesenchymal stem cells (MSCs) and damages bone marrow blood vessels. We wished to investigate the efficacy of antioxidant administration in protecting stem cell microenvironments and promoting bone marrow vasculature recovery after radiation treatment. The antioxidant ascorbic acid was administered 3 times at a dosage: 150 mg/kg/day to experimenttal groups 3 days before targeted radiation by a unique Small Animal Radiation Research Platform (SARRP). Histological staining indicated that antioxidant treated mice had less severe bone marrow damage 1 week after irradiation with substantial marrow cellular recovery 4 weeks later. Flow cytometry analysis showed that antioxidant administration was correlated with a rebound in MSC quantity in bone marrow. Anti-oxidant treatment was also observed to allow for better vasculature retention and recovery through angiographic imaging. Our data suggests that pre-treatment with ascorbic acid serves to improve bone marrow microenvironments for bone marrow stem cells after radiation treatment.

Expression pattern of GATA-1,-2 and-3 genes in leukemic bone marrow microenvironment

Objective： The aim of the study was to investigate the expression pattern of hematopoietic transcription factor GATA-1, -2 and -3 genes in leukemic bone marrow （BM） micreenvironment [including bone marrow stremal cells （BMSCs） and BM hematopoietic cells]. Methods： Mononuclear cells were isolated from BM of patients with acute myeloid leukemia （AML）, chronic myelogenous leukemia （CML）, or acute lymphoblasUc leukemia （ALL）. Adherent cells （BMSCs） and nonadherent ceils （BM hematopoietic cells） were collected after long-term culture in vitro. The semi-quantitative expression levels of GATA genes in the BMSCs or BM hematopoietic cells from patients with leukemia were analyzed by using RT-PCR-ELISA and com- pared with normal controls. Results： The expression level of GATA-1 gene in the BMSCs from CML group was significantly lower than that of the normal controls. The expression level of GATA-3 gene in the BMSCs from ALL was higher than that of the normal controls, but that from CML was lower than the normal controls. Dominant expression of GATA-3 gene was found in the normal BM hematopoietic cells. The dominant expression of GATA-2 gene was found in the normal BMSCs and the BMSCs from CML, whereas the dominant expression of GATA-3 gene was detected in the BMSCs from AML. Conclusion： GATA-1, -2 and -3 genes might play a role in hematopoiesis regulation in leukemia, and the changes of expression pattern of GATA genes might influence the hematopoiesis in BM microenvironment and relate to the pathogenesis and development of leukemia.

当归多糖调节骨髓造血微环境治疗再生障碍性贫血的机制

背景:如何改善造血微环境是目前再生障碍性贫血治疗的热点问题。目的:结合GEO测序分析、网络药理学与实验验证当归多糖改善骨髓造血微环境治疗再生障碍性贫血的作用机制。方法:借助GEO数据库获得了再生障碍性贫血相关差异表达基因并进行GO和GSEA分析。结合文献与PubChem、SwissTargetPrediction、PharmMapper数据库获取当归多糖活性成分和靶点。取交集靶点后利用STRING和Cytoscape构建蛋白相互作用网络,并进行GO和KEGG富集分析。构建再生障碍性贫血小鼠模型,利用血细胞分析仪、流式细胞术、ELISA、免疫组化、免疫荧光染色、Western blot方法验证当归多糖对再生障碍性贫血的疗效与作用机制。结果与结论:(1)共筛选出834个差异表达基因,参与细胞发育、造血、髓系细胞分化等生物学过程;(2)检索得到当归多糖相关347个靶点并筛选出77个潜在治疗基因,其中VEGFA、EGLN1、BCL2、干扰素γ、白细胞介素2、白细胞介素4、白细胞介素6等血管生成、凋亡及免疫相关因子度值显著;(3)KEGG通路富集分析治疗靶点主要富集在Th17细胞分化、NK相关细胞毒性、细胞黏附因子等干扰素γ、白细胞介素2、白细胞介素4相关信号通路;(4)动物实验表明,当归多糖能够显著改善再生障碍性贫血小鼠骨髓造血,增加外周血细胞及骨髓单个核细胞计数,提高小鼠存活率;与模型组相比,当归多糖组小鼠Th1/Th2细胞比例显著下降(P<0.01),干扰素γ水平显著降低(P<0.01),白细胞介素4水平升高(P<0.05),VEGFA表达显著升高(P<0.01),EGLN1表达显著降低(P<0.01),骨髓单个核细胞凋亡率、活性氧水平显著降低(P<0.01),Cleaved Caspase-3蛋白表达显著增高(P<0.01),Bcl-2/Bax比值显著降低(P<0.01);(5)结果表明:当归多糖能够通过调节异常T细胞亚群,促进血管生成以改善造血微环境,并抑制骨髓单个核细胞凋亡,以改善再生障碍性贫血小鼠的造血功能。

运动预处理联合骨髓间充质干细胞移植治疗大鼠心肌梗死

背景:干细胞疗法在改善心肌梗死后心脏重构方面具有广阔前景,但心肌微环境改变影响干细胞疗效。运动预处理类似于缺血预处理,能够对心肌产生保护作用。然而,运动预处理与干细胞移植联合作用的效果与机制鲜有关注。目的:观察运动预处理对心肌梗死大鼠骨髓间充质干细胞移植效果的影响,探讨局部炎症微环境在其中的作用机制。方法:80只雌性SD大鼠随机分为假手术组、模型组、移植组和联合组,每组20只。利用结扎冠状动脉左前降支的方法制作心肌梗死大鼠模型,假手术组仅穿线不结扎。移植组和联合组造模后于心肌内注射雄性大鼠来源骨髓间充质干细胞,此外,联合组在造模前还需进行8周跑台运动(即运动预处理)。干细胞移植后4周,采用递增负荷运动力竭实验测定运动能力,超声心动术测定心脏结构与功能,压力容积导管法检测左心室血液动力学,原位染色法进行心肌组织病理学观察并获取心肌胶原容积分数。干细胞移植后1,7 d和4周,采用定量反转录聚合酶链反应检测左心室促炎症因子(白细胞介素1β、白细胞介素6、肿瘤坏死因子α)、抗炎症因子(白细胞介素10)、Y染色体性别决定区和胚胎基因(心房钠尿肽、脑钠肽、β-肌球蛋白重链)m RNA表达量。结果与结论:(1)干细胞移植后4周:与假手术组比较,模型组运动能力、左心室射血分数降低(P <0.05);心肌梗死面积、心肌细胞横截面积、胶原容积分数增加(P <0.05);胚胎基因以及促炎因子m RNA表达量上调(P <0.05),白细胞介素10 m RNA表达量下调(P <0.05)。与模型组比较,移植组运动能力、左心室射血分数增加(P <0.05);心肌梗死面积、心肌细胞横截面积、胶原容积分数下降(P <0.05);胚胎基因以及促炎因子m RNA表达量下调(P <0.05),白细胞介素10 m RNA表达量无显著性变化(P> 0.05)。与移植组比较,联合组上述各指标均进一步改善(P<0.05)。(2)干细胞移植后1,7d:与移植组比较,联合组Y染色体性别决定区m RNA表达量升高(P<0.05)。(3)相关分析显示,白细胞介素1β、白细胞介素6(除移植后1 d)、肿瘤坏死因子α与Y染色体性别决定区m RNA表达量呈负相关(P <0.05),白细胞介素10与Y染色体性别决定区m RNA表达量呈正相关(P <0.05)。结果表明:运动预处理能够增强骨髓间充质干细胞移植治疗心肌梗死大鼠的效果,表现为心脏重构得到抑制、心功能进一步提升,其机制与心肌炎症微环境改善促进骨髓间充质干细胞滞留和存活有关。

Effects of T-2 Toxin Exposure on Bone Metabolism and Bone Development of Mice

T-2 toxin is the most widespread mycotoxin in crops,feed and food,which poses a serious threat to body health.Bone is the main target tissue for T-2 toxin accumulation.Ingestion of food contaminated by T-2 toxin is the main cause of Kashin-Beck disease.However,the specific mechanism of bone damage caused by T-2 toxin is still unclear.In this study,a total of 40 male C57BL/6N mice were divided into four groups and orally treated with 0,0.5,1.0 and 2.0 mg·kg^(-1) body weight T-2 toxin for 28 days.The results showed that exposure to T-2 toxin led to weight loss,bone mineral density reduction and femoral structural damage of mice.In addition,osteoblast-mediated bone formation was inhibited,and osteoclast-mediated bone resorption was enhanced.Meanwhile,the levels of bone metabolism-related hormones including parathyroid hormone,calcitonin and 1,25-dihydroxyvitamin D3 were reduced.More importantly,it was found that the level of neuropeptide Y(a neurohormone)was decreased.These results provided a new perspetive for understanding the osteotoxicity of T-2 toxin.

间充质干细胞在急性髓系白血病骨髓微环境中的研究进展

急性髓系白血病(acute myeloid leukemia, AML)是一种高度异质性、多基因突变驱动的血液肿瘤,具有发病率高、致死率高的特点。间充质干细胞(mesenchymal stem cells, MSCs)是具有自我更新、多向分化潜能的多能干细胞,是骨髓微环境中的重要细胞成分。研究表明,MSCs通过转移线粒体、传递细胞外囊泡、促进自身成脂分化、分泌促癌蛋白等多种机制促进AML的发生发展。该文就MSCs在AML骨髓微环境中的作用作一综述,为靶向MSCs治疗AML的新策略提供参考。

Bone metastases:When and how lung cancer interacts with bone

Bone metastasis is a common and debilitating consequence of lung cancer:30%-40% of patients with nonsmall cell lung cancer develop bone metastases during the course of their disease. Lung cancer cells find a favorable soil in the bone microenvironment due to factors released by the bone matrix, the immune system cells, and the same cancer cells. Many aspects of the cross-talk among lung tumor cells, the immune system,and bone cells are not clear, but this review aims to summarize the recent findings in this field, with particular attention to studies conducted to identify biomarkers for early detection of lung cancer bone metastases.

The Effects of Ligustrazine on the Expression of bFGF and bFGFR in Bone Marrow in Radiation Injured Mice

To study the expression of the bFGF and its receptor in the mouse bone marrow by treatment with acute radioactive injury and Ligustrazine, 56 mice were divided into 3 groups: normal group, radiation injured group and Ligustrazine group. After irradiation by 6.0 Gy 60 Co γ ray, each mouse was orally given 0.1 ml Ligustrazine twice a day for 13 days in Ligustrazine group, and each mouse in radiation injured group was orally given equal amount of saline. On the 3rd, 7th, 14th day after irradiation, bone marrow mono nuclear cells (BMMNC) were counted, and the expression levels of bFGF and bFGFR in bone marrow were evaluated by immunohistochemistry and flow cytometry analysis respectively. On the 3rd, 7th, 14th day after irradiation, expression of bFGF in bone marrow were significantly lower than in normal group ( P <0.05 or P <0.01). Expressions of bFGF and bFGFR were much higher in Ligustrazine treated group than that in the control group ( P <0.05 or P <0.01). Ligustrazine potentiate the expression of bFGF and bFGFR in bone marrow MNC to recover the bone marrow hematopoiesis inductive microenvironment, which is one of the mechanisms by which Ligustrazine rebuild the bone marrow hematopoiesis after acute radioactive injury.

3D/4D printed bio-piezoelectric smart scaffolds for next-generation bone tissue engineering

Piezoelectricity in native bones has been well recognized as the key factor in bone regeneration.Thus,bio-piezoelectric materials have gained substantial attention in repairing damaged bone by mimicking the tissue’s electrical microenvironment(EM).However,traditional manufacturing strategies still encounter limitations in creating personalized bio-piezoelectric scaffolds,hindering their clinical applications.Three-dimensional(3D)/four-dimensional(4D)printing technology based on the principle of layer-by-layer forming and stacking of discrete materials has demonstrated outstanding advantages in fabricating bio-piezoelectric scaffolds in a more complex-shaped structure.Notably,4D printing functionality-shifting bio-piezoelectric scaffolds can provide a time-dependent programmable tissue EM in response to external stimuli for bone regeneration.In this review,we first summarize the physicochemical properties of commonly used bio-piezoelectric materials(including polymers,ceramics,and their composites)and representative biological findings for bone regeneration.Then,we discuss the latest research advances in the 3D printing of bio-piezoelectric scaffolds in terms of feedstock selection,printing process,induction strategies,and potential applications.Besides,some related challenges such as feedstock scalability,printing resolution,stress-to-polarization conversion efficiency,and non-invasive induction ability after implantation have been put forward.Finally,we highlight the potential of shape/property/functionality-shifting smart 4D bio-piezoelectric scaffolds in bone tissue engineering(BTE).Taken together,this review emphasizes the appealing utility of 3D/4D printed biological piezoelectric scaffolds as next-generation BTE implants.

Curcumin Inhibits Prostate Cancer Bone Metastasis by Up-Regulating Bone Morphogenic Protein-7 <i>in Vivo</i>

A number of studies have focused on the beneficial properties of Curcumin (diferuloyl methane, used in South Asian cuisine and traditional medicine) such as the chemoprevention of cancer. Recent studies have also indicated that this material has significant benefits for the treatment of cancer and is currently undergoing several clinical trials. We have been interested in the application of this compound as a therapeutic agent for advanced prostate cancer, particularly the skeletal complications in this malignancy. Our earlier work indicated that this compound could inhibit the osteomimetic properties which occur in castration resistant prostate cancer cells, by interfering with the common denominators between these cancer cells and the bone cells in the metastatic tumor microenvironment, namely the osteoblasts and the osteoclast. We predicted that curcumin could break the vicious cycle of reciprocal stimulation that results in uncontrolled osteolysis in the bony matrix. In this work, we have evaluated the potential of this compound in inhibiting the bone metastasis of hormone refractory prostate cancer cells in an established animal model. Our results strongly suggest that curcumin modulates the TGF-βsignaling that occurs due to bone matrix degradation by up-regulating the metastasis inhibitory bone morphogenic protein-7 (BMP-7). This enhancement of BMP-7 in the context of TGF-β in the tumor microenvironment is shown to enhance the mesenchymal-to-epithelial transition. Most importantly, we show that as a result of BMP-7 up-regulation, a novel brown/beige adipogenic differentiation program is also up-regulated which plays a role in the inhibition of bone metastasis. Our results suggest that curcumin may subvert the TGF-β signaling to an alternative adipogenic differentiation program in addition to the previously established interference with the osteomimetic properties, thus inhibiting the bone metastatic processes in a chemopreventive as well as therapeutic setting.

Cell transplantation therapies for spinal cord injury focusing on bone marrow mesenchymal stem cells:Advances and challenges

Spinal cord injury(SCI)is a devastating condition with complex pathological mechanisms that lead to sensory,motor,and autonomic dysfunction below the site of injury.To date,no effective therapy is available for the treatment of SCI.Recently,bone marrow-derived mesenchymal stem cells(BMMSCs)have been considered to be the most promising source for cellular therapies following SCI.The objective of the present review is to summarize the most recent insights into the cellular and molecular mechanism using BMMSC therapy to treat SCI.In this work,we review the specific mechanism of BMMSCs in SCI repair mainly from the following aspects:Neuroprotection,axon sprouting and/or regeneration,myelin regeneration,inhibitory microenvironments,glial scar formation,immunomodulation,and angiogenesis.Additionally,we summarize the latest evidence on the application of BMMSCs in clinical trials and further discuss the challenges and future directions for stem cell therapy in SCI models.