Therapeutic effect of Cistanche deserticola on defecation in senile constipation rat model through stem cell factor/C-kit signaling pathway

BACKGROUND Constipation is one of the chronic gastrointestinal functional diseases.It seriously affects the quality of life.Cistanche deserticola(C.deserticola)can treat constipation obviously,but its mechanism has not been clarified.We supposed that mechanism of it improved the intestinal motility by stimulating interstitial Cajal cells(ICC).Activation of the C-kit receptor on the surface of ICC is closely related to ICC function,and the stem cell factor(SCF)/C-kit signaling pathways plays an important role on it.To investigate the mechanism of how C.deserticola treats constipation,this study aimed to establish a constipation model in rats and explore the role of SCF/C-kit signaling pathway in the treatment.AIM To explore the SCF/C-kit signaling pathways in the role of C.deserticola for treatment of constipation by a constipation rat model.METHODS Forty-eight 8-mo-old Sprague–Dawley rats were divided into 4 groups by random weight method:Normal group(n=12),model group(n=12),C.deserticola group(n=12)and blocker group(n=12).The normal group received normal saline by gavage;the model group received loperamide by gavage;the blocker group received loperamide and C.deserticola by gavage,and STI571 was injected by intraperitoneally.During treatment,the weight,fecal granules and fecal quality were recorded every 10 d.On day 20 after model induction,the colon tissues of each group were removed.Hematoxylin and eosin staining was used to observe pathological changes.Expression levels of SCF,C-kit and Aquaporin genes were detected by immunohistochemistry,western blotting,and real-time-quantitative polymerase chain reaction.The colonic epithelial mitochondria and goblet cells were observed by transmission electron microscopy.RESULTS Compared with the normal group,as treatment progressed,the weight of rats in the model and blocker groups decreased significantly,the stool weight decreased,and the stool quality was dry(P<0.05).C.deserticola reversed the decrease in body weight and stool weight and improved stool quality.Histopathological analysis indicated that the colonic mucosal epithelium in the model group was incomplete,and the arrangement of the glands was irregular or damaged.Treatment with C.deserticola improved the integrity and continuity of the epithelial cells and regular arrangement of the glands.The blocking agents inhibited the effects of C.deserticola Immunohistochemistry and real-timequantitative polymerase chain reaction showed that expression of SCF and C-kit protein or genes in the colonic tissue of the model group was decreased(P<0.05),while treatment with C.deserticola increased protein or gene expression(P<0.05).Western blotting showed that expression of aquaporin APQ3 was increased,while the expression of Cx43 decreased in the model group.Treatment with C.deserticola inhibited expression of APQ3 and promoted expression of Cx43.Transmission electron microscopy showed that the mitochondria of the colonic epithelium in the model group were swollen and arranged disorderly,and microvilli were sparse.The condition was better in the C.deserticola group.Mice treated with STI571 blocker confirmed that blocking the SCF/C-kit pathway inhibited the improvement of constipation by C.deserticola.CONCLUSION C.deserticola improved defecation in rats with constipation,and the SCF/C-kit signaling pathway,which is a key link of ICC function,played an important role of the treatment.

Expression change of stem cell-derived neural stem/progenitor cell sup-porting factor gene in injured spinal cord of rats

Objective To explore the expression change of stem cell-derived neural stem/progenitor cell supporting factor （SDNSF） gene in the injuried spinal cord tissues of rats, and the relation between the expressions of SDNSF and nestin. Methods The spinal cord contusion model of rat was established according to Allen＇s falling strike method. The expression of SDNSF was studied by RT-PCR and in situ hybridization （ISH）, and the expression of nestin was detected by immunochemistry. Results RT-PCR revealed that SDNSF mRNA was upregulated on day 4 after injury, peaked on day 8-12, and decreased to the sham operation level on day 16. ISH revealed that SDNSF mRNA was mainly expressed in the gray matter cells, probably neurons, of spinal cord. The immunohistochemistry showed that accompanied with SDNSF mRNA upregulation, the nestin-positive cells showed erupted roots, migrated peripherad and proliferation on the 8-day slice. However, the distribution pattern of these new cells was different from that of SDNSF-positive cells. Conclusion （1） SDNSF is expressed in the gray matter of spinal cord. The expression of SDNSF mRNA in the spinal cord varies with injured time. （2） The nestin-positive cells proliferate accompanied with spinal cord injury repair, but do not secrete SDNSF.

Role of Stem Cell Factor and Its Receptor in the Pathogenesis of Pediatric Aplastic Anemia

In order to investigate the levels of stem cell factor (SCF) and its receptor c-kit protein and mRNA in pediatric aplastic anemia (AA) and their relevance to the pathogenesis, immunocytochemical and in situ hybridization were utilized to detect the expression of SCF and its receptor c-kit gene protein and mRNA, respectively in 59 children with AA and 51 normal controls. The relationship between SCF and c-kit and the pathogenesis of AA was analyzed subsequently. The results showed that the positive rate of SCF protein and mRNA expression in children with AA was significantly lower than that in healthy controls (P<0.05). However, there was no significant difference in the positive rate of c-kit protein and mRNA expression between children with AA and control group (P>0.05). It was concluded that the expression of SCF is significantly decreased in children with AA, which may be closely associated with the pathogenesis of the AA. c-kit may be unrelated to the development of pediatric AA. Therefore, AA in children may have abnormalities at SCF/c-kit signal transduction levels.

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.

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.

Nerve growth factor promotes in vitro proliferation of neural stem cells from tree shrews

Neural stem cells promote neuronal regeneration and repair of brain tissue after injury,but have limited resources and proliferative ability in vivo.We hypothesized that nerve growth factor would promote in vitro proliferation of neural stem cells derived from the tree shrews,a primate-like mammal that has been proposed as an alternative to primates in biomedical translational research.We cultured neural stem cells from the hippocampus of tree shrews at embryonic day 38,and added nerve growth factor（100 μg/L） to the culture medium.Neural stem cells from the hippocampus of tree shrews cultured without nerve growth factor were used as controls.After 3 days,fluorescence microscopy after DAPI and nestin staining revealed that the number of neurospheres and DAPI/nestin-positive cells was markedly greater in the nerve growth factor-treated cells than in control cells.These findings demonstrate that nerve growth factor promotes the proliferation of neural stem cells derived from tree shrews.

Denervated hippocampus provides a favorable microenvironment for neuronal differentiation of endogenous neural stem cells

Fimbria-fornix transection induces both exogenous and endogenous neural stem cells to differentiate into neurons in the hippocampus.This indicates that the denervated hippocampus provides an environment for neuronal differentiation of neural stem cells.However,the pathways and mechanisms in this process are still unclear.Seven days after fimbria fornix transection,our reverse transcription polymerase chain reaction,western blot assay,and enzyme linked immunosorbent assay results show a significant increase in ciliary neurotrophic factor m RNA and protein expression in the denervated hippocampus.Moreover,neural stem cells derived from hippocampi of fetal（embryonic day 17） Sprague-Dawley rats were treated with ciliary neurotrophic factor for 7 days,with an increased number of microtubule associated protein-2-positive cells and decreased number of glial fibrillary acidic protein-positive cells detected.Our results show that ciliary neurotrophic factor expression is up-regulated in the denervated hippocampus,which may promote neuronal differentiation of neural stem cells in the denervated hippocampus.

Mesenchymal stem cells-derived exosomes ameliorate blue light stimulation in retinal pigment epithelium cells and retinal laser injury by VEGF-dependent mechanism

AIM： To observe the effect of exosomes derived from human umbilical cord blood mesenchymal stem cells（h UCMSCs） on the expression of vascular endothelial growth factor-A（VEGF-A） in blue light injured human retinal pigment epithelial（RPE） cells and laser-induced choroidal neovascularization（CNV） in rats.METHODS： Exosomes were isolated from h UCMSCs and characterized by transmission electron microscope and Western blot. MSCs-derived exosomes were cultured with RPE cells exposed to blue light. The m RNA and protein expression of VEGF-A were determined by real time-polymerase chain reaction（PCR） and Western blot, respectively. Immunofluorescence assay was used for the detection of the expression level of VEGF-A. We injected different doses of MSCs-derived exosomes intravitreally to observe and compare their effects in a mouse model of laserinduced retinal injury. The histological structure of CNV in rats was inspected by hematoxylin-eosin（HE） staining and fundus fluorescein angiography. The expression of VEGF-A was detected by immunohistochemistry.RESULTS： Exosomes exhibited the typical characteristic morphology（cup-shaped） and size（diameter between 50 and 150 nm）. The exosomes marker, CD63, and h UCMSCs marker, CD90, showed a robust presence. In vitro, MSCsderived exosomes downregulated the m RNA（Exo-L： t=6.485, 7.959, 9.286; Exo-M： t=7.517, 10.170, 13.413; Exo-H： t=10.317, 12.234, 14.592, P〈0.05） and protein（Exo-L： t=2.945, 4.477, 6.657; Exo-M： t=4.713, 6.421, 8.836; Exo-H：t=6.539, 12.194, 12.783; P〈0.05） expression of VEGF-A in RPE cells after blue light stimulation. In vivo, we found that the MSCs-derived exosomes reduced damage, distinctly downregulated VEGF-A（Exo-H： t=0.957, 1.382; P〈0.05）, and gradually improved the histological structures of CNV for a better visual function（Exo-L： 0.346, Exo-M： 3.382, Exo-H： 8.571; P〈0.05）. CONCLUSION： MSCs-derived exosomes ameliorate blue light stimulation in RPE cells and laser-induced retinal injury via downregulation of VEGF-A.

Mobilization Efficiency of Granulocyte Colony-stimulating Factor and Stem Cell Factor to Bone Marrow Mononuclear Cells and Mechanisms

The mobilization efficiency of granulocyte colony-stimulating factor (G-CSF) and stem cell factor (SCF) to bone marrow mononuclear cells (MNCs) in mice was observed, and the changes of CXCL12/CXCR4 signal were detected in order to find out the mobilization mechanism of stem cells. Kunming mice were randomly divided into two groups. The mice in treatment group were subjected to subcutaneous injection of G-CSF at a dose of 100 μg/kg and SCF at a dose of 25 μg/kg every day for 5 days, and those in control group were given isodose physiological saline. The MNCs were separated, counted and cultured, and the colony-forming unit-fibroblast (CFU-F) was evaluated. CD34+CXCR4+ MNCs were sorted by flow cytometry. The expression of CXCL12 protein in bone marrow extracellular fluid was detected by ELISA, and that of CXCL12 mRNA in bone marrow was measured by RT-PCR. The results showed that the counts of MNCs in peripheral blood and bone marrow were increased after administration of G-CSF/SCF (P<0.01). The factors had a dramatic effect on the expansion capability of CFU-F (P<0.05). Flow cytometric of bone marrow MNCs surface markers revealed that CD34+CXCR4+ cells accounted for 44.6%±8.7% of the total CD34+ MNCs. Moreover, G-CSF/SCF treatment induced a decrease in bone marrow CXCL12 mRNA that closely mirrored the fall in CXCL12 protein. In this study, it is evidenced that G-CSF/SCF can effectively induce MNCs mobilization by disrupting the balance of CXCL12/CXCR4 signaling pathway in the bone marrow and down-regulating the interaction of CXCL12/CXCR4.

VEGF-expressing Bone Marrow Mesenchymal Stem Cells Transplantation Improved Heart Function of Myocardial Infarct Rabbits

Objectives To treat myocardial infarction with MSCs transplantation combined with VEGF gene therapy in rabbits and to study its mechanisms. Methods Forty-eight rabbits were randomly divided into MI group （n=12）, MSCs group （n=12）, VEGF group （n=12）, MSCs＋VEGF group （M＋V group, n=12）. Rabbit myocardial infarction models were founded by the ligation of left anterior descending artery. 107 MSCs were injected into the infarct-zone in four sites 2 weeks later in MSCs and M＋ V group, phVEGF gene were injected in infarct-zone in VEGF group and MSCs transfected with phVEGF gene were injected in M＋V group. Heart function including LVEDP, LVSP, LVDP, -dp/dtmax, ＋dp/dtmax, were measured in vivo. The hearts were harvested at 4 weeks after transplantation and sectioned for HE stain, immunohistochemical stain of BrdU and VIII factor antigen. Results The left ventricular hemodynamics parameters showed that heart function were improved more in M＋V group than MSCs group, MI group and VEGF group. The numbers of BrdU positive cells in M＋ V group（61±8）were more than in MSCs group （44±8, P 〈 0.01）. The numbers of vessels in infarcted zone were more in M＋V group （49±8） than in MSCs group （33±6, P 〈 0.01）,VEGF group（30±8, P 〈 0.01）and Mlgroup （18±4, P〈0.01）. Conclusions VEGF-expressing MSCs transplantation could improve heart function after myocardial infarction, and they were more effective than sole MSCs transplantation. Keeping more MSCs survival and ameliorating the blood supply of infarct-zone might be involved in the mechanisms.

CO-TRANSFECTION OF RAT BONE MARROW MESENCHYMAL STEM CELLS WITH HUMAN BMP2 AND VEGF165 GENES

Objective To explore the feasibility and efficacy of lentivirus-mediated co-transfection of rat bone marrow mesenchymal stem cells （MSCs） with human vascular endothelial growth factor 165 （hVEGFI65） gene and human bone morphogenetic protein 2 （hBMP2） gene. Methods The hVEGF165 and hBMP2 cDNAs were obtained from human osteosarcoma cell line MG63 and cloned into lentiviral expression vectors designed to co-express the copepod green fluorescent protein （copGFP）. The expression lentivector and packaging Plasmid Mix were co-transferred to 293TN cells, which produced the lentivirus carrying hVEGF165 （Lv-VEGF） or hBMP2 （ Lv-BMP） , respectively. MSCs of Wistar rats were co-transfected with Lv-BMP and Lv-VEGF （BMP ＋ VEGF group）, or each alone （BMP group and VEGF group）, or with no virus （ Control group）. The mRNA and protein expressions of hVEGF165 and hBMP2 genes in each group were detected by real-time PCR and enzyme linked immunosorbent assay （ELISA）. Results Lentiviral expression vectors carrying hVEGF165 or hBMP2 were correctly constructed and confirmed by restriction endonucleses analysis and DNA sequencing analysis. A transfer efficiency up to 90% was archieved in all the transfected groups detected by the fraction of fluorescent cells using fluorescent microscopy. From the results generated by real-time PCR and ELISA, VEGF165 and BMP2 genes were co-expressed in BMP ＋ VEGF group. No significant difference of BMP2 expression was detected between BMP ＋ VEGF and BMP groups （ P 〉 0. 05）. Similarly, there was no significant difference of VEGF165 expression between BMP ＋ VEGF and VEGF groups （ P 〉 0. 05）. Conclusion VEGF165 and BMP2 genes were successfully co-expressed in MSCs by lentivirus-mediated co-transfection, which provided a further foundation for the combined gene therapy of bone regeneration.

Differentiation of Rabbit Bone Marrow Mesenchymal Stem Cells to Myogenic Cells and Expression of VEGF After Gene Transfection

Objectives To induce the differentiation of rabbit bone marrow mesenchymal stem cells （MSCs） to myogenic cells in vitro, and to investigate the expression of vascular endothelial growth factor （VEGF） gene in MSCs transfected by AdTrackCMV-VEGF165. Methods MSCs were isolated and purified from rabbit bone marrow by percoll （11）73 g/ml） and then cultured in low glucose DMEM with 10% FBS. AdTrackCMV-VEGF165 eukaryotic expression vector was constructed and transfected into the MSCs. After being incubated with 5-azacytidine （5- Aza）, the expression of troponin I in MSCs was assayed by immunohistochemistry and the expression of VEGF gene was identified by northern blot and western blot. The concentration of VEGF in the supernatant was measured by ELASA. Results MSCs were isolated and cultured successfully from rabbit bone marrow. The positive cTnI stain of some MSCs after the induction of 5-aza indicated that the cells were differentiated to myogenic cells. Northern blot and western blot showed that the expression of VEGF 165 mRNA was much higher in the hVEGF165 gene transfected cells than that of the control. The concentration of VEGF in the supernatant got to the peak 3-5 days after hVEGF165 gene transfection （1011- 1027 pg/ml） and decreased gradually thereafter, but still higher than that of control group or pAdTrackCMV group （349 pg/mLvs 116 pg/mL or 125pg/ml respectively, MSCs could be induced P〈 0.01）. Conclusions to differentiate to myogenic cells by 5-aza in vitro and could express VEGF by VEGF gene transfection.

Epithelial stem cell islands in the regenerated epidermis

Objective: The effects of growth factors on wound healing have been studied extensively, however, their molecular and genetic mechanisms that regulate epidermal regeneration are not fully understood. In this study, we explore the cell reversion characteristics and epithelial stem cell distribution in human regenerated epidermis treated with recombinant human epidermal growth factor (rhEGF). Methods:Tissue biospies from 8 regenerated skins treated with rhEGF were used to evaluate the cell reversion.

Chondrogenic differentiation of human bone mesenchymal stem cells treated with growth differentiation factor 5 under hypoxia

Objective To explore the feasibility and effectiveness of the self-assembly cartilage tissue engineered with chondrogenically differentiated human bone mesenchymal stem cells (hBMCs) induced by growth differentiation factor-5 (GDF-5)

Effect of the implant composite of poly lactide-co-glycolide and bone mesenchymal stem cells modified by basic fibroblast growth factor on injured spinal cord in rats

Objective To investigate the effect of the implant composite of poly lactide-co-glycolide(PLGA)and bone mesenchymal stem cells (BMSCs) modified by basic fibroblast growth factor (bFGF) on injured spinal cord in rats.Methods Two hundred and

Construction of the Eukaryotic Expression Vector with EGFP and hVE GF121 Gene and its Expression in Rat Mesenchymal Stem Cells

Objectives To construct a recombinant plasmid carrying enhanced green fluore- scent protein (EGFP) and human vascular endothelial growth factor (VEGF) 121 gene and detect its expre- ssion in rat mesenchymal stem cells (MSCs). Methods Human VEGF121 cDNA was amplified with polymerase chain reaction (PCR) from pCD/hVEGF121 and was inserted into the eukaryotic expression vector pEGFP- C1. After being identified with PCR, double enzyme digestion and DNA sequencing. The recombinant plasmid pEGFP/hVEGF121 was transferred into rat MSCs with lipofectamine. The expression of EGFP/VEGF121 fusion protein were detected with fluorescence microscope and immunocytochemical staining respectively. Results The recombinant plasmid was confirmed with PCR, double enzyme digestion and DNA sequencing. The fluoresce- nce microscope and immunocytochemical staining results showed that the EGFP and VEGF121 protein were expressed in MSCs 48 h after transfection. Conclusions The recombinant plasmid carrying EGFP and human VEGF was successfully constructed and expressed positively in rat MSCs. It offers a promise tool for further research on differentiation of MSCs and VEGF gene therapy for ischemial cardiovascular disease.

Loss of interstitial cells of Cajal network in severe idiopathic gastroparesis

AIM: To report a case of severe idiopathic gastroparesis in complete absence of Kit-positive gastric interstitial cells of Cajal (ICC). METHODS: Gastric tissue from a patient with severe idiopathic gastroparesis unresponsive to medical treatment and requiring surgery was analyzed by conventional histology and immunohistochemistry. RESULTS: Gastric pacemaker cells expressing Kit receptor had completely disappeared while the local level of stem cell factor, the essential ligand for its development and maintenance, was increased. No signs of cell death were observed in the pacemaker region. CONCLUSION: These results are consistent with the hypothesis that a lack of Kit expression may lead to impaired functioning of ICC. Total gastrectomy proves to be curative.

Interleukin-1 beta induces the expression and production of stem cell factor by epithelial cells： crucial involvement of the PI-3K/mTOR pathway and HIF-1 transcription complex

Potential crosslinks between inflammation and leukaemia have been discussed for some time, but experimental evidence to support this dogma is scarce. In particular, it is important to understand the mechanisms responsible for potential upregulation of proto-oncogenic growth factor expressions by inflammatory mediators. Here, we investigated the ability of the highly inflammatory cytokine interleukin-1 beta （IL-1β） to induce the production of stem cell factor （SCF）, which is a major hematopoietic growth factor that controls the progression of acute myeloid leukaemia upon malignant transformation of haematopoietic myeloid cells. We found that human IL-1β induced the expression/secretion of SCF in MCF-7 human epithelial breast cancer cells and that this process depended on the hypoxia-inducible factor 1 （HIF-1） transcription complex. We also demonstrated a crucial role of the phosphatidylinositol-3 kinase （PI-3K）/mammalian target of rapamycin （mTOR） pathway in IL-1β-induced HIF-1α accumulation in MCF-7 cells. Importantly, mTOR was also found to play a role in IL-1β-induced SCF production. Furthermore, a tendency for a positive correlation of IL-1β and SCF levels in the plasma of healthy human donors was observed. Altogether, our results demonstrate that IL-1β, which normally bridges innate and adaptive immunity, induces the production of the major haematopoietic/proleukaemic growth factor SCF through the PI-3K/mTOR pathway and the HIF-1 transcription complex. These findings strongly suoDort a cross-talk between inflammation and acute mveloid leukaemia.

Effect of growth and differentiation factor 6 on the tenogenic differentiation of bone marrow-derived mesenchymal stem cells

Background Recent studies showed that bone marrow-derived mesenchymal stem ceils （BMSCs） had risk of ectopic bone formation. In this study, we aimed to investigate the effect of growth and differentiation factor 6 （GDF-6） on the tenogenic differentiation of BMSCs in vitro, and then combined with small intestine submucous （SIS） to promote tendon regeneration in vivo. Methods The BMSCs were isolated from the green fluorescent protein （GFP） rats, and were characterized by multi-differentiation assays following our previous study protocol. BMSCs cultured with different concentrations of GDF-6, without growth factors served as control. After 2 weeks, mRNA expression and protein expression of tendon specific markers were examined by qRT-PCR and Western blotting to define an optimal concentration of GDF-6. Mann-Whitney U-test was used to compare the difference in relative mRNA expression among all groups; P 〈0.05 was regarded as statistically significant. The GDF-6 treated BMSCs combined with SIS were implanted in nude mice and SD rat acute patellar tendon injury model, the BMSCs combined with SIS served as control. After 12 and 4 weeks in nude mice and tendon injury model, the samples were collected for histology. Results After the BMSCs were treated with different concentration of GDF-6 for 2 weeks, the fold changes of the specific markers （Tenomodulin and Scleraxis） mRNA expression were significantly higher in GDF-6 （20 ng/ml） group （P 〈_0.05）, which was also confirmed by Western blotting result. The BMSCs became parallel in orientation after GDF-6 （20 ng/ml） treatment, but the BMSCs in control group were randomly oriented. The GDF-6 （20 ng/ml） treated BMSCs were combined with SIS, and were implanted in nude mice for 12 weeks, the histology showed neo-tendon formation. In the SD rat patellar tendon window injury model, the histology also indicated the GDF-6 （20 ng/ml） treated BMSCs combined with SIS could promote tendon regeneration. Conclusions GDF-6 has tenogenic effect on the tenogenic differentiation of BMSCs, and GDF-6 （20 ng/ml） has better tenogenic effect compared to other concentrations. The GDF-6 （20 ng/ml） treated BMSCs combined with SIS can form neo-tendons and promote tendon regeneration.

Amphiphilic cytokine traps remodel marrow adipose tissue for hematopoietic microenvironment amelioration

Hematopoietic stem cell transplantation(HSCT)is extensively employed in the treatment of hematological malignancies but is markedly constrained by the paucity of hematopoietic stem/progenitor cells(HSPCs).Recent studies have found that marrow adipose tissue(MAT)acts on hematopoiesis through complicated mechanisms.Therefore,the osteo-organoids fabricated in vivo using biomaterials loaded with recombinant human bone morphogenetic protein 2(rhBMP-2)have been used as models of MAT for our research.To obtain sufficient amounts of therapeutic HSPCs and healthy MAT,we have developed amphiphilic chitosan(AC)-gelatin as carriers of rhBMP-2 to the regulate type conversion of adipose tissue and trap hematopoietic growth factors.Unlike medicine interventions or cell therapies,the traps based on AC not only attenuate the occupancy of adipocytes within the hematopoietic microenvironment while preserving stem cell factor concentrations,but also improve marrow metabolism by promoting MAT browning.In conclusion,this approach increases the proportion of HSPCs in osteo-organoids,and optimizes the composition and metabolic status of MAT.These findings furnish an experimental basis for regulating hematopoiesis in vivo through materials that promote the development of autologous HSPCs.Additionally,this approach presents a theoretical model of rapid adipogenesis for the study of adipose-related pathologies and potential pharmacological targets.