BACKGROUND:Previous studies have demonstrated that the cannabinoid type Ⅰ receptor can enhance the proliferation and neural differentiation of neural stem cells and mesenchymal stem cells.Moreover,cannabinoid type Ⅰ also governs the proliferation and mineralization capacity of human apical papilla stem cells.However,there are relatively few investigations concerning the impact of cannabinoid type Ⅰ overexpression on the neural differentiation of human apical papilla stem cells.OBJECTIVE:To investigate the effect of cannabinoid type Ⅰ on neural differentiation of human apical papilla stem cells in vitro.METHODS:Healthy third molars with immature root tips that need to be removed for orthodontic treatment were collected,and human apical papilla stem cells were isolated and cultured by tissue block method combined with enzyme digestion method.Cannabinoid type Ⅰ gene was introduced into human apical papilla stem cells by lentivirus-mediated transfection technique.A blank control group,a negative control group,and cannabinoid type Ⅰ overexpression group were set up.The transfection effect of overexpression of cannabinoid type Ⅰ lentivirus on human apical papilla stem cells was verified by Western Blot.The control group,negative control group,cannabinoid type Ⅰ overexpression group and cannabinoid type Ⅰ overexpression+AM251(cannabinoid type Ⅰ receptor antagonist)group were set up.Cell proliferation was detected by CCK-8 assay at 1,5,and 10 days after neural induction.On day 10 of neural induction,the expression levels of TH,NeuroD-1,and NCAM1 genes were detected by qRT-PCR,and the protein expression levels of Nestin and TUBB3 were detected by immunofluorescence.RESULTS AND CONCLUSION:(1)Compared with the blank control group and the negative control group,the expression of cannabinoid receptor Ⅰ protein in the cannabinoid receptor Ⅰ overexpression group was significantly increased,and the difference was significant(P＜0.05).(2)Compared with the blank control group and the negative control group,the proliferation ability of human apical papilla stem cells in the cannabinoid type Ⅰ overexpression group was the strongest at 5 and 10 days after neural induction(P＜0.05).(3)Compared with the blank control group and the negative control group,the mRNA expression of NeuroD-1,NCAM1,and TH in the stem cells of the human apical papilla in the cannabinoid type Ⅰ overexpression group was significantly increased,and the fluorescence intensity of Nestin and TUBB3 was significantly enhanced(P＜0.05).(4)Compared with the cannabinoid type Ⅰ overexpression group,the proliferation ability,mRNA expression level of NeuroD-1,NCAM1,and TH,as well as the fluorescence intensity of Nestin and TUBB3,were significantly decreased in the cannabinoid type Ⅰ overexpression+AM251 group(P＜0.05).These findings conclude that overexpression of cannabinoid type Ⅰ promoted the proliferation and neural differentiation of human apical dentin papilla stem cells.

BACKGROUND:BCR/ABL gene is a specific gene of Ph chromosome-positive acute lymphoblastic leukemia,and its expression level has become a sensitive indicator for monitoring minimal residual disease before and after allogeneic hematopoietic stem cell transplantation.However,whether the expression level of BCR/ABL gene before transplantation affects the efficacy of transplantation and how to guide the early intervention of relapse with tyrosine kinase inhibitors after transplantation is still inconclusive.OBJECTIVE:To explore the relationship between BCR/ABL gene expression and recurrence in patients with Ph chromosome positive acute lymphoblastic leukemia before and after related and allogeneic hematopoietic stem cell transplantation.METHODS:Twenty-four patients with Ph chromosome positive acute lymphoblastic leukemia who achieved complete hematological remission and underwent allogeneic hematopoietic stem cell transplantation were selected at the Affiliated Hospital of North China University of Science and Technology between January 2015 and December 2022.Real time fluorescence quantitative polymerase chain reaction was used to dynamically detect the expression levels of BCR/ABL genes during treatment,representing minimal residual disease.Based on BCR/ABL gene expression,tyrosine kinase inhibitors combined with chemotherapy was administered before transplantation to select the timing of allogeneic hematopoietic stem cell transplantation.After transplantation,the disease status was evaluated to guide the use of tyrosine kinase inhibitors,and an early intervention plan for recurrence was developed.RESULTS AND CONCLUSION:Follow-up was until December 2023,with a median follow-up time of 49(12-82)months.There were 8 cases of hematological recurrence,with a median recurrence time of 14(8-39)months and a cumulative recurrence rate of 33％(8/24).Univariate analysis showed that recurrence after allogeneic hematopoietic stem cell transplantation was not significantly correlated with gender,age,extramedullary complications,time from diagnosis to transplantation,HLA typing,acute graft-versus-host disease,and chronic graft-versus-host disease(P＞0.05).There was a significant correlation between the relief treatment course and minimal residual disease levels before transplantation.The second hematology completely resolution and positive minimal residual disease before transplantation had a higher hematological recurrence rate(P＜0.05).The 3-year cumulative recurrence rate,disease-free survival rate,and overall survival rate were 27％,63％,and 74％;the 5-year cumulative recurrence rate,disease-free survival rate,and overall survival rate were 38％,57％,and 74％,respectively.It is concluded that Ph chromosome positive acute lymphoblastic leukemia patients with BCR/ABL gene positive before transplantation have a higher recurrence rate.BCR/ABL gene expression after transplantation can guide the application of tyrosine kinase inhibitors and serve as a basis for early intervention in recurrence.

BACKGROUND:Lysosomal storage diseases,as a group of rare genetic metabolic disorders,exhibit complex pathogenesis often leading to dysfunction of cells,tissues,and organs.Current therapeutic approaches have certain limitations.Stem cell transplantation,as an emerging treatment method,offers new options for patients with lysosomal storage diseases.OBJECTIVE:To review the mechanisms of action of stem cells in regulating lysosomes for the treatment of lysosomal storage diseases and explore the feasibility of traditional Chinese medicine in treating such diseases,providing new insights for the treatment of lysosomal storage diseases with stem cells.METHODS:Relevant literature from 2010 to 2024 was searched in CNKI and PubMed databases using keywords"stem cells,lysosomal storage disease,lysosome"in English and Chinese.Ultimately,78 articles were included for review and analysis.RESULTS AND CONCLUSION:(1)Stem cells treat lysosomal storage diseases by regulating lysosomes primarily through three aspects:regulating stem cell differentiation and replacement,improving intercellular communication and the microenvironment,and enhancing lysosomal enzyme expression through gene editing.(2)Stem cells have achieved significant effects in the treatment of some lysosomal storage diseases,such as Niemann-Pick disease,mucopolysaccharidoses,Gaucher disease,and metachromatic leukodystrophy.(3)The procedure for stem cell transplantation needs further optimization.Adverse reactions post-transplantation urgently need to be addressed,and the efficiency and safety of gene-modified stem cells also need to be further improved.In the future,more research on the treatment of lysosomal storage diseases with traditional Chinese medicine is required to reveal the relevant mechanisms for the treatment of lysosomal storage diseases with traditional Chinese medicine.

BACKGROUND:Exosomes are nanoscale extracellular vesicles secreted by various types of cells,with advantages such as high bioavailability,low toxicity,low immunogenicity,and good biocompatibility.However,natural exosomes have certain limitations in clinical therapy.By using bioengineering techniques to modify and engineer exosomes,the engineered exosomes not only improve their original therapeutic effects but also exhibit excellent biostability and targeting specificity,showing great potential for application in the field of tissue repair.OBJECTIVE:To summarize the various strategies for engineering exosomes,including functional loading and surface modification,outline the research progress of engineered exosomes in different tissue repairs,and explore the therapeutic potential of engineered exosomes in tissue repair.METHODS:PubMed database was searched for relevant literature published between 2010 and 2024 using the search terms"engineered exosomes,tissue repair,biomaterials,tissue engineering,wound healing,parenchyma,bone regeneration,cartilage,neural,myocardial,hepatic."Studies that were not closely related to the article's theme,of poor quality,repetitive,or outdated were excluded.A total of 115 articles met the inclusion criteria.RESULTS AND CONCLUSION:(1)Functional loading is used to combine therapeutic molecules with exosomes to obtain additional properties or to enhance the original physiological function of the exosome,among which ultrasonication and extrusion are simple to operate and can obtain higher drug loading capacity at the same time.(2)Surface modification can make exosomes express desired proteins or enhance their targeting,including genetic engineering and chemical modification.Genetic engineering is complicated,poorly reproducible,and the end product is poorly controllable.Chemical modification,on the other hand,is relatively simple and versatile,and is more suitable for designing highly targeted and functionally specific engineered exosomes.(3)Among the techniques for pre-treating cells to obtain engineered exosomes,hypoxic pre-treatment is more widely used because of its simplicity and clearer mechanism,which can activate glycolysis to promote cell proliferation,and regulate the vascular endothelial growth factor receptor signaling pathway through the generation of hypoxia-inducible factors to promote angiogenesis.(4)The function of exosomes is affected by various factors such as cell source,cell state,synthesis process,and extracellular environment.If the engineering strategy is complicated,it is more difficult to ensure the functional consistency of the final engineered exosomes,so the relatively simple and reliable engineering strategy is more suitable for its clinical application.(5)Engineered exosomes combined with biomaterials or scaffolds can be used to treat complex wounds of skin soft tissue,such as infected wounds and diabetic ulcers.This approach enhances exosome delivery and controls their release,promotes tissue repair,controls infection,and regulates the local microenvironment of the wound.(6)A single mechanism of engineered exosomes is often ineffective due to the specificity of the bone tissue fracture,so dual or even multi-functional engineered exosomes are needed to promote fracture repair while anti-inflammatory or remodeling the vascular system.(7)The source of exosomes has a significant impact on neural tissue repair.Exosomes derived from different neural cells promote neural repair through different effects.In addition,the combination of stents and engineered exosomes for traumatic brain injury has obvious advantages,the stent itself provides hemostasis and support,combined with the engineered exosomes itself to promote the repair effect,can obtain better therapeutic effect.(8)In cardiac and hepatic tissue repair,it is needed to develop anti-fibrotic engineered exosomes to resist the abnormal repair of cardiac and hepatic tissues themselves,which will require further research in the future.

BACKGROUND:Exosomes derived from mesenchymal stem cells play pivotal roles in cell communication and epigenetic regulation due to their low immunogenicity and targeted delivery effects,and have been clinically applied in the treatment of various diseases.OBJECTIVE:To review the isolation,purification,identification methods,and application progress of mesenchymal stem cell-derived exosomes,and to facilitate the development of large-scale preparation techniques and clinical translation of mesenchymal stem cell-derived exosomes.METHODS:The Chinese search terms"exosome,mesenchymal stem cells,isolation,purification,characterization,clinical application"and the English search terms"exosome,extracellular vesicles,mesenchymal stem cells,isolation,characterization,application"were used to search the literature published before September 2024 in CNKI,PubMed,and Web of Science databases.Articles with poor relevance to the topic,outdated,or duplicated content were excluded,and finally,109 articles were included for review.RESULTS AND CONCLUSION:(1)This paper reviews recent methods for isolating and purifying exosomes,comparing the characteristics of ultracentrifugation,ultrafiltration,size-exclusion chromatography,polymer precipitation,immunoaffinity,microfluidic methods,and other novel approaches based on their underlying principles.(2)Methods for identifying exosomes can be categorized into physical and biochemical analyses,characterizing exosomes based on their shape,size,and characteristic proteins.(3)Mesenchymal stem cell-derived exosomes have broad applications in multiple fields such as medical aesthetics,wound repair,and cancer treatment,due to their immune-regulatory properties and ability to cross biological barriers.(4)The clinical translation of exosomes faces challenges due to their complex structure,lack of universal isolation techniques,and poor stability,making it difficult to achieve in a short period of time.

BACKGROUND:Aging of human body may be due to the senescence and depletion of various stem cells in the body.Bone marrow mesenchymal stromal cells have important physiological functions and have shown certain therapeutic effects on various diseases.It is of great significance to study the senescence and mechanism of bone marrow mesenchymal stromal cells.OBJECTIVE:To investigate whether human bone marrow mesenchymal stromal cells exhibit senescence phenotypes with increasing donor age,and further determine whether endogenous retrovirus drives the senescence of bone marrow mesenchymal stromal cells,offering a novel reference for the investigation of stem cell senescence mechanism.METHODS:The senescence of bone marrow mesenchymal stromal cells at different ages was characterized by flow cytometry,β-galactosidase staining,qPCR,western blotting,and EdU fluorescence imaging.Bone marrow mesenchymal stromal cells and cell culture supernatant were collected from donors of different ages.The content of human endogenous retrovirus was detected by qPCR.Furthermore,highly sensitive droplet digital PCR was used to detect the expression of endogenous retrovirus-like particles in the cell culture supernatant.The content of endogenous retrovirus in bone marrow plasma samples of different ages was detected by ELISA.RESULTS AND CONCLUSION:Bone marrow mesenchymal stromal cells exhibited obvious senescence with increasing age,including significant morphological changes,increased proportion of β-galactosidase positive cells,increased expression of senescence markers P16 and P21 protein,decreased expression of LMNB1 protein,and reduced cell proliferation ability.There was no significant difference in the content of endogenous retrovirus in bone marrow mesenchymal stromal cells at different ages,almost no endogenous retrovirus-like particles in the cell culture supernatant.There was no significant difference in endogenous retrovirus-like particles detected in bone marrow plasma samples at different ages.These findings indicate that human bone marrow mesenchymal stromal cells have normal physiological senescence with increasing age,but the mechanism of senescence is not mediated by abnormal activation of endogenous retroviruses,which may have a more complex driving mechanism.

BACKGROUND:One of the advantages of clear aligner treatment is molar distalization.However,tooth tilting movement and loss of anterior anchorage may occur during treatment.There are few studies on whether these problems can be improved by selecting clear aligners with different thicknesses and edges to improve the clinical treatment effect.OBJECTIVE:To analyze the control ability of clear aligners with different thickness and edges on the central incisor,lateral incisor,and second molar when pushing the maxillary second molar distally by three-dimensional finite element analysis.METHODS:Three-dimensional finite element analysis models of bilateral maxillary second molar distalization with clear aligner,maxillary dentition,periodontal ligament,and alveolar bone with different thicknesses and margins were established by Mimics,Geomagic Wrap,3-matic and SolidWorks software,respectively.There were 16 combinations of four thicknesses(0.4,0.5,0.625,and 0.75 mm)and four margins(scallop,straight,straight extension 2 mm and straight extension 4 mm).The data were imported into Ansys Workbench software for design and solution.The mean value,peak value and distribution of the periodontal ligament equivalent stress of the second molar,the equivalent stress and the maximum initial displacement of the second molar,and the control ability of each appliance on the second molar,central incisor,and lateral incisor were analyzed.RESULTS AND CONCLUSION:(1)The mean equivalent stress of periodontal ligament of the second molar,the equivalent stress of the second molar and the maximum initial displacement of the second molar increased with the extension of the appliance edge and the increase of the thickness of the appliance in the 16 groups of models.(2)When the thickness of appliances was the same,the maximum equivalent stress of the second molar in the linear appliance group was the highest,and the maximum equivalent stress of the second molar in the linear extended appliance group was greater than that in the scallop appliance group.When the edge of the appliance was the same,the periodontal ligament equivalent stress peak of the second molar increased with the increase of the thickness of the appliance.The equivalent stress distribution in the periodontal ligament of the second molar in the linear extendable appliance group was more uniform than that in the scallop appliance group and the linear appliance group.(3)When the thickness of the appliance was the same,the scallop-shaped appliance had the worst control on the second molar.When the edge of the appliance was the same,with the increase of the thickness of the appliance,the control of the second molar by the linear extender appliance was gradually stronger than that by the linear appliance.The control of the central incisor was stronger and more stable with the linear extended 2 mm appliance,while the control of the lateral incisor was stronger and more stable with the linear appliance.(4)The results showed that when using clear aligners to push molars distally,extending the edge of the appliance could improve the control of the molars and reduce the tilting movement of the teeth.The design of a straight extension margin of 2 mm for the central incisor and a straight edge for the lateral incisor can enhance the control of the anchorage incisor and reduce the labial inclination of the anterior teeth.

BACKGROUND:Mesenchymal stem cells show extremely therapeutic potential for radiation-induced lung injury through delivering exosomes.Age is a primary factor affecting the function and biological efficacy of mesenchymal stem cells.OBJECTIVE:To investigate the protective effects of exosomes derived from bone marrow mesenchymal stem cells of different mouse ages on radiation-induced lung injury in mice.METHODS:Bone marrow mesenchymal stem cells of young mice and old mice were obtained by whole bone marrow adherent culture.The exosomes were isolated from the supernatant of passage 3 bone marrow mesenchymal stem cells.Ten 2-month-old C57BL/6J mice were randomly selected as the control group after anesthesia and not irradiated.The remaining 30 2-month-old C57BL/6J mice were used to establish a mouse radiation-induced lung injury model and were randomly divided into three groups.Exosomes derived from bone marrow mesenchymal stem cells of young mice,exosomes derived from bone marrow mesenchymal stem cells of old mice,and PBS were injected through the tail vein,respectively.The survival rate of mice was monitored.The lung function,lung inflammation and fibrosis were assessed at 1 and 12 weeks after irradiation.RESULTS AND CONCLUSION:(1)The concentrations of particles and proteins in exosomes derived from bone marrow mesenchymal stem cells of young mice were higher than those in exosomes derived from bone marrow mesenchymal stem cells of old mice.(2)Compared with the control group,the survival rate of mice in the PBS group was low,and lung inflammation was obvious at week 1 after irradiation,and the levels and mRNA expressions of interleukin-1β,interleukin-6,and tumor necrosis factor-α were increased.Collagen deposition in lung tissues was observed at week 12 after irradiation,and the mRNA level of E-cadherin was decreased,while the mRNA levels of α-smooth muscle actin,transforming growth factor-β1,and β-catenin were increased.(3)Compared with the PBS group,the survival rate of mice in the exosome group was significantly improved,and the level of proinflammatory factors and their mRNA expression were reduced at week 1 after irradiation,the mRNA level of E-cadherin was increased,and the mRNA levels of α-smooth muscle actin,transforming growth factor β1 and β-catenin were reduced at week 12 after irradiation.(4)Among all the above indicators,the therapeutic effect of exosomes derived from bone marrow mesenchymal stem cells of young mice was better than that of exosomes derived from bone marrow mesenchymal stem cells of old mice.(5)The results showed that exosomes derived from bone marrow mesenchymal stem cells of young mice contained more particles and proteins,and the effect of alleviating early inflammation and late fibrosis of radiation-induced lung injury in mice was better than that of exosomes derived from bone marrow mesenchymal stem cells of old mice.

BACKGROUND:Pearl powder is rich in many active ingredients,which can promote the proliferation and migration of fibroblasts,thus promoting wound healing and skin tissue regeneration.However,the effect of nano-pearl powder water-soluble matrix on proliferation,migration and apoptosis of mouse fibroblasts L929 has not been reported.OBJECTIVE:To investigate the effect of nano-pearl powder water-soluble matrix on the proliferation,migration and apoptosis of mouse fibroblasts L929.METHODS:Passage 6 L929 cells were divided into five groups.The negative control group did not add any material;the positive control group added PBS,and the low,medium and high mass concentration groups of water-soluble matrix were added with 10,25 and 40 μg/mL of nano-pearl powder water-soluble matrix,respectively.The proliferation of L929 cells was detected by MTT assay.The migration ability of L929 cells was detected by Transwell.The apoptosis rate of L929 cells was detected by flow cytometry.The expressions of apoptosis-related proteins Bax,Bcl-2,and Caspase-1 were detected by western blot assay.RESULTS AND CONCLUSION:(1)The results of MTT assay and Transwell chamber experiment showed that the water-soluble matrix of nano-pearl powder could promote the proliferation and migration of L929 cells,and it was concentration dependent.(2)Flow cytometry and western blot assay results showed that the water-soluble matrix of nano-pearl powder could reduce the apoptosis rate of L929 cells and the protein expression of Bax and Caspase-1,and increase the expression of Bcl-2 protein,and it was concentration dependent.(3)These findings exhibited that the water-soluble matrix of nano-pearl powder could inhibit cell apoptosis under high mass concentration treatment.The results show that the water-soluble matrix of nano-pearl powder can promote the proliferation and migration of fibroblasts and inhibit the apoptosis of fibroblasts.

BACKGROUND:Currently,miR-196b-5p has been found to play a role in cell proliferation,migration and inhibition of scar hyperplasia,but there is a lack of relevant studies on whether it plays a role in the process of wound healing.OBJECTIVE:To investigate the effect of miR-196b-5p in adipose stem cell-derived exosomes on burn wound healing.METHODS:The models of deep second degree skin burn in SD rats were established and randomly divided into four groups:blank control group,exosome group,agomiR-196b-5p group,and exosome+antagomiR-196b-5p group,with 10 rats in each group.PBS,adipose-derived stem cell-derived exosomes,miR-196b-5p agonist,and miR-196b-5p inhibitor were injected around the wound according to different groups.Wound healing was observed immediately after injury and on days 7,14,and 21 after injury.On day 7 after surgery,hematoxylin-eosin staining was used to observe the expression of inflammation in the wound surface.On day 14 after suregery,Masson staining was used to observe the expression of collagen and immunohistochemical staining was used to observe the expression of CD31 in the wound surface.On day 7 after surgery,western blot assay was performed to detect the expression of α-smooth muscle actin and type Ⅰ collagen in the wound surface.RESULTS AND CONCLUSION:(1)The wound healing was faster in the agomiR-196b-5p group,while it was slower in the blank control group and the exosome+antagomiR-196b-5p group.(2)Compared with the blank control group and the exosome+antagomiR-196b-5p group,the wound infiltration of inflammatory cells was less in the exosome group and the agomiR-196b-5p group,and the expression of CD31 was significantly increased(P＜0.01).(3)Compared with the blank control group and the exosome+antagomiR-196b-5p group,the expression levels of α-smooth muscle actin and type Ⅰ collagen were increased in the exosome group and the agomiR-196b-5p group(P＜0.05).These findings indicate that miR-196b-5p in adipose stem cell-derived exosomes can promote burn wound healing in rats.