OBJECTIVE: To prepare clinical-grade human umbilical cord-derived mesenchymal stem cells (hUC-MSC) with high expression of hematopoietic supporting factors and evaluate their stem cell characteristics. METHODS: Fetal umbilical cord tissues were collected from healthy postpartum women during full-term cesarean section. Wharton's jelly was mechanically separated and hUC-MSCs were obtained by explant culture method and enzyme digestion method in an animal serum-free culture system with addition of human platelet lysate. The phenotypic characteristics of hUC-MSCs obtained by two methods were detected by flow cytometry. The differences in proliferation ability between the two groups of hUC-MSCs were identified through CCK-8 assay and colony forming unit-fibroblast (CFU-F) assay. The differences in multilineage differentiation potential between the two groups of hUC-MSCs were identified through induction of adipogenic, osteogenic, and chondrogenic differentiation. The mRNA expression levels of hematopoietic supporting factors such as SCF, IL-3, CXCL12, VCAM1 and ANGPT1 in the two groups of hUC-MSCs were identified by real-time fluorescence quantiative PCR(RT-qPCR). RESULTS: The results of flow cytometry showed that hUC-MSCs obtained by the two methods both expressed high levels of CD73, CD90 and CD105, while lowly expressed CD31, CD45 and HLA-DR. The results of CCK-8 and CFU-F assay showed that the proliferation ability of hUC-MSCs obtained by explant culture method was better than those obtained by enzyme digestion method. The results of the triple lineage differentiation experiment showed that there was no significant difference in multilineage differentiation potential between the two grous of hUC-MSCs. The results of RT-qPCR showed that the mRNA expression levels of hematopoietic supporting factors SCF, IL-3, CXCL12, VCAM1 and ANGPT1 in hUC-MSCs obtained by explant cultrue method were higher than those obtained by enzyme digestion method. CONCLUSION Clinical-grade hUC-MSCs with high expression levels of hematopoietic supporting factors were successfully cultured in an animal serum-free culture system.
Humans ; Mesenchymal Stem Cells/metabolism* ; Umbilical Cord/cytology* ; Cell Differentiation ; Female ; Cell Proliferation ; Cells, Cultured ; Chemokine CXCL12/metabolism* ; Angiopoietin-1/metabolism* ; Vascular Cell Adhesion Molecule-1/metabolism* ; Stem Cell Factor/metabolism* ; Flow Cytometry ; Pregnancy

Objective To explore the role of miR-429 in synovial mesenchymal stem cell-derived exosomes(SMSC-Exos)in repairing cartilage damage in temporomandibular joint osteoarthritis(TMJ OA)by extracting SMSC-Exos from human synovial tissue and screening differentially expressed microRNA(miRNA)through transcriptome sequencing.Methods Human synovial tissues were obtained from 6 patients who underwent surgery at the First Medical Center of the Chinese PLA General Hospital from June to December 2023,including 3 patients with osteoarthritis(OA group)and 3 control patients(control group),all of whom were male.SMSC-Exos were extracted from the synovial tissues for miRNA sequencing and differential expression analysis.Further,Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analyses were performed on the target genes of differentially expressed miRNA to identify key functional miRNA and construct miRNA-target gene regulatory networks and protein-protein interaction(PPI)networks of target genes.An in vitro model of rabbit condylar cartilage cell inflammatory microenvironment induced by interleukin-1β(IL-1β)was established,with the control group cultured in DMEM/F12 basic medium and the inflammation-induced group cultured in DMEM/F12 basic medium containing 10 ng/ml IL-1β.RT-qPCR was used to detect the effects of overexpressed target miRNA on the mRNA expression levels of cartilage phenotype factors such as type Ⅱ collagen α1 chain(Col2a1),aggrecan(Acan),as well as inflammatory factors including a disintegrin and metalloproteinase with thrombospondin motifs 5(Adamts5)and cyclooxygenase-2(Cox-2).Results(1)SMSC-Exos were successfully isolated,cultured,and identified.(2)miRNA sequencing of SMSC-Exos from OA and control groups revealed 16 differentially expressed miRNAs(|log2FC|>2,P<0.05).Compared with control group,7 miRNAs were up-regulated and 9 were down-regulated in OA group.GO and KEGG analysis indicated that the target genes of miR-429 were mainly involved in development process,anatomical structure development,system development,cell development and differentiation,and were enriched in inflammation-related pathways such as mitogen-activated protein kinase(MAPK)and phosphatidylinositol 3-kinase-protein kinase B(PI3K-Akt).(3)Functional validation of miR-429 in the rabbit condylar cartilage cell inflammatory model showed that overexpression of miR-429 increased the mRNA expression levels of Col2a1 and Acan(P<0.05)and decreased the mRNA expression levels of Adamts5 and Cox-2(P<0.05)in the inflammation-induced group.Conclusions miRNA sequencing of SMSC-Exos isolated and identified from human synovial tissues reveals a specific miRNA expression profile in OA patients,with miR-429 significantly down-regulated.Functional validation demonstrates that overexpression of miR-429 has reparative and anti-inflammatory effects on condylar cartilage cells in an inflammatory microenvironment.

Objective To establish a stable,reliable,and clinically relevant porcine model of endotoxin-induced acute respiratory distress syndrome(ARDS).Methods Ten 8-month-old male Bama minipigs were deeply sedated,followed by invasive mechanical ventilation and electrocardiographic monitoring.Lipopolysaccharide(LPS)was intravenously pumped at 600 μg/(kg·h)for 3 hours,then maintained at 15 μg/(kg·h)thereafter.Dynamic monitoring was performed at five time points after LPS injection(LPS 0,1,3,5,and 8 h),including arterial blood gas analysis and chest computed tomography(CT)scans.Pathological examination of lung tissues obtained via bronchoscopic biopsy(HE staining and transmission electron microscopy)was conducted.These indicators were comprehensively used to evaluate the success of the animal model.Results At 5 hours after LPS administration,8 minipigs developed symptoms such as skin cyanosis,elevated body temperature,and respiratory distress.The oxygenation index decreased to<300 mmHg.Chest CT scans showed diffuse pulmonary infiltrates.Histopathology revealed alveolar edema and hyaline membrane formation.Transmission electron microscopy demonstrated disruption of pulmonary blood-air barrier,depletion of lamellar bodies in type Ⅱ pneumocytes,inflammatory cell infiltration,and exudation of plasma proteins and fibrin.Compared with LPS 0 h,at LPS 8 h,the oxygenation index and arterial blood pH were significantly decreased(P<0.001),while blood lactic acid and serum potassium were significantly increased(P<0.05);serum calcium and base excess were significantly decreased(P<0.05),and the lung injury score based on HE-stained lung sections was significantly increased(P<0.01).Conclusion The porcine ARDS model established by continuous LPS injection can dynamically simulate the pathophysiological characteristics and typical pathological manifestations of clinical septic ARDS,making it an effective tool to study the pathogenesis,prevention,and treatment strategies of septic ARDS.

Objective:To explore the safety and efficacy of intraosseous regional administration (IORA) of vancomycin for preventing infection in primary total knee arthroplasty (TKA).Methods:A total of 124 patients with knee osteoarthritis undergoing TKA between February 2024 and May 2024 at nine hospitals were enrolled. Preoperative infection prophylaxis involved either IORA (0.5 g vancomycin administered via intraosseous regional infusion before incision) or intravenous infusion (1 g vancomycin via peripheral vein). The IORA group included 15 males and 47 females with a median age of 66.5 years (range, 60.0-70.0 years), while the intravenous group included 14 males and 48 females with a median age of 66.0 years (range, 61.8-70.3 years) years. Intraoperative samples were collected including fat and synovium tissues after incision, before prosthesis placement, and after tourniquet release; distal femoral cancellous bone during femoral osteotomy; proximal tibial cancellous bone during tibial osteotomy; proximal intercondylar cancellous bone before prosthesis placement; and peripheral blood from non-infused arms at surgery initiation and after tourniquet release. Vancomycin concentrations were measured using liquid chromatography-tandem mass spectrometry. Vital sign changes were recorded from admission to 5~10 minutes post-IORA (IORA group) or post-incision (intravenous group). Follow-ups were conducted on postoperative day 1 and 3, and at 1 and 3 months, to document complications including IORA-related adverse events, periprosthetic joint infections, surgical site infections, red man syndrome, acute kidney injury, deep vein thrombosis and so on.Results:Vancomycin concentrations in bone, fat, and synovial tissue samples were significantly higher in the IORA group than in the intravenous group ( P<0.05), while vancomycin concentrations in blood samples were significantly lower in the IORA group than in the intravenous group ( P<0.05). Only 7.3%(41/558) of tissue samples in the IORA group had vancomycin concentrations below 2.0 μg/g (the minimum inhibitory concentration of vancomycin against coagulase-negative staphylococcus), compared to 59.3%(331/558) in the intravenous group (χ 2=11.285, P<0.001). In the intravenous group, 16.9%(21/124) of blood samples had vancomycin concentrations exceeding 15.0 mg/L (the threshold associated with a significantly increased risk of nephrotoxicity), while all concentrations in the IORA group were below this threshold, the difference was statistically significant (χ 2=22.943, P<0.001). There were no statistically significant difference ( P>0.05) in vital signs changes before and after vancomycin administration between the two groups. Two patients in the intravenous group experienced incision exudate, while no other related complications occurred in either group. Conclusions:Compared to the traditional intravenous infusion of 1 g vancomycin, intraosseous injection of a low dose (0.5 g) of vancomycin achieves higher local tissue concentrations in the knee joint with a lower incidence of adverse reactions and is safe for infection prophylaxis. Despite guidelines not recommending the routine use of vancomycin for preventing infection after primary TKA, intraosseous injection of 0.5 g vancomycin may be considered intraoperatively for primary TKA in the following scenarios: patients in medical institutions with a high prevalence of methicillin-resistant staphylococcus aureus (MRSA) infections, patients with potential preoperative MRSA colonization, or patients with cephalosporin allergy.

Objective:To explore the protective mechanism of dexmedetomidine (Dex) in a model of broncho-pulmonary dysplasia (BPD) in mice exposed to hyperoxia.Methods:Neonatal rats were randomly assigned to four groups:air control group,hyperoxia injury group,Dex control group,and hyperoxia+Dex group,with six animals in each group.The air control and Dex control groups were exposed to ambient air,while the hyperoxia injury and hyperoxia+Dex groups were exposed to 90% O 2.The Dex control and hyperoxia+Dex groups received daily intraperitoneal injections of Dex at a dosage of 500 μg/kg.Lung tissue samples were collected after 7 days.Histomorphological changes in lung tissue were evaluated using hematoxylin and eosin (HE) staining,and mitochondrial ultrastructural changes in type I epithelial cells of neonatal rat lung tissue were observed via transmission electron microscopy.The activity of Complex Ⅰ in neonatal rat lung tissue was assessed.The expression levels of PINK1 and Parkin in neonatal rat lung tissue were measured using quantitative PCR (qPCR).Western blot analysis was conducted to determine the protein expression levels of PINK1 and Parkin in lung tissues. Results:Under transmission electron microscopy,mitochondrial structures were intact in the lung tissues of both the air control group and the Dex control group.However,significant mitochondrial damage was observed in the hyperoxia injury group,while the hyperoxia+Dex group exhibited some relief from mitochondrial damage compared to the hyperoxia injury group.The activity of the oxidized respiratory chain Complex Ⅰ in the hyperoxia injury group was significantly lower than that in the air control group (4.824±0.804 vs.15.276±0.804, P<0.05) and the hyperoxia+Dex group(4.824±0.804 vs.9.648±0.804, P<0.05).After qPCR analysis,the expression levels of PINK1 and Parkin in the hyperoxia injury group were higher than those in the air control group(1.80±0.06 vs.1.00±0.07,2.10±0.14 vs.1.00±0.09, P<0.05),but lower than those in the hyperoxia+Dex group(1.80±0.06 vs.3.61±0.19,2.10±0.10 vs.4.24±0.43, P<0.05).Western blot analysis revealed that the expression levels of PINK1 and Parkin in the hyperoxia injury group were higher than those in the air control group(2.16±0.11 vs.1.00±0.01,3.82±0.13 vs.1.00±0.01, P<0.05),but lower than those in the hyperoxia+Dex group(2.16±0.11 vs.3.35±0.14,3.82±0.13 vs.5.48±0.15, P<0.05).There were no significant differences in mitochondrial structure integrity,Complex Ⅰ enzyme activity,or the expression levels of PINK1 and Parkin,as assessed by qPCR and Western blot analysis,between the air control and Dex control groups( P>0.05). Conclusion:Dex effectively mitigates mitochondrial ultrastructural damage in BPD model mice,enhances the activity of Complex Ⅰ in the oxidative respiratory chain,reduces mitochondrial damage,and increases the activation of the PINK1-Parkin-mediated mitophagy pathway,thereby promoting lung protection.

Objective:To explore the safety and efficacy of intraosseous regional administration (IORA) of vancomycin for preventing infection in primary total knee arthroplasty (TKA).Methods:A total of 124 patients with knee osteoarthritis undergoing TKA between February 2024 and May 2024 at nine hospitals were enrolled. Preoperative infection prophylaxis involved either IORA (0.5 g vancomycin administered via intraosseous regional infusion before incision) or intravenous infusion (1 g vancomycin via peripheral vein). The IORA group included 15 males and 47 females with a median age of 66.5 years (range, 60.0-70.0 years), while the intravenous group included 14 males and 48 females with a median age of 66.0 years (range, 61.8-70.3 years) years. Intraoperative samples were collected including fat and synovium tissues after incision, before prosthesis placement, and after tourniquet release; distal femoral cancellous bone during femoral osteotomy; proximal tibial cancellous bone during tibial osteotomy; proximal intercondylar cancellous bone before prosthesis placement; and peripheral blood from non-infused arms at surgery initiation and after tourniquet release. Vancomycin concentrations were measured using liquid chromatography-tandem mass spectrometry. Vital sign changes were recorded from admission to 5~10 minutes post-IORA (IORA group) or post-incision (intravenous group). Follow-ups were conducted on postoperative day 1 and 3, and at 1 and 3 months, to document complications including IORA-related adverse events, periprosthetic joint infections, surgical site infections, red man syndrome, acute kidney injury, deep vein thrombosis and so on.Results:Vancomycin concentrations in bone, fat, and synovial tissue samples were significantly higher in the IORA group than in the intravenous group ( P<0.05), while vancomycin concentrations in blood samples were significantly lower in the IORA group than in the intravenous group ( P<0.05). Only 7.3%(41/558) of tissue samples in the IORA group had vancomycin concentrations below 2.0 μg/g (the minimum inhibitory concentration of vancomycin against coagulase-negative staphylococcus), compared to 59.3%(331/558) in the intravenous group (χ 2=11.285, P<0.001). In the intravenous group, 16.9%(21/124) of blood samples had vancomycin concentrations exceeding 15.0 mg/L (the threshold associated with a significantly increased risk of nephrotoxicity), while all concentrations in the IORA group were below this threshold, the difference was statistically significant (χ 2=22.943, P<0.001). There were no statistically significant difference ( P>0.05) in vital signs changes before and after vancomycin administration between the two groups. Two patients in the intravenous group experienced incision exudate, while no other related complications occurred in either group. Conclusions:Compared to the traditional intravenous infusion of 1 g vancomycin, intraosseous injection of a low dose (0.5 g) of vancomycin achieves higher local tissue concentrations in the knee joint with a lower incidence of adverse reactions and is safe for infection prophylaxis. Despite guidelines not recommending the routine use of vancomycin for preventing infection after primary TKA, intraosseous injection of 0.5 g vancomycin may be considered intraoperatively for primary TKA in the following scenarios: patients in medical institutions with a high prevalence of methicillin-resistant staphylococcus aureus (MRSA) infections, patients with potential preoperative MRSA colonization, or patients with cephalosporin allergy.

Objective:To explore the protective mechanism of dexmedetomidine (Dex) in a model of broncho-pulmonary dysplasia (BPD) in mice exposed to hyperoxia.Methods:Neonatal rats were randomly assigned to four groups:air control group,hyperoxia injury group,Dex control group,and hyperoxia+Dex group,with six animals in each group.The air control and Dex control groups were exposed to ambient air,while the hyperoxia injury and hyperoxia+Dex groups were exposed to 90% O 2.The Dex control and hyperoxia+Dex groups received daily intraperitoneal injections of Dex at a dosage of 500 μg/kg.Lung tissue samples were collected after 7 days.Histomorphological changes in lung tissue were evaluated using hematoxylin and eosin (HE) staining,and mitochondrial ultrastructural changes in type I epithelial cells of neonatal rat lung tissue were observed via transmission electron microscopy.The activity of Complex Ⅰ in neonatal rat lung tissue was assessed.The expression levels of PINK1 and Parkin in neonatal rat lung tissue were measured using quantitative PCR (qPCR).Western blot analysis was conducted to determine the protein expression levels of PINK1 and Parkin in lung tissues. Results:Under transmission electron microscopy,mitochondrial structures were intact in the lung tissues of both the air control group and the Dex control group.However,significant mitochondrial damage was observed in the hyperoxia injury group,while the hyperoxia+Dex group exhibited some relief from mitochondrial damage compared to the hyperoxia injury group.The activity of the oxidized respiratory chain Complex Ⅰ in the hyperoxia injury group was significantly lower than that in the air control group (4.824±0.804 vs.15.276±0.804, P<0.05) and the hyperoxia+Dex group(4.824±0.804 vs.9.648±0.804, P<0.05).After qPCR analysis,the expression levels of PINK1 and Parkin in the hyperoxia injury group were higher than those in the air control group(1.80±0.06 vs.1.00±0.07,2.10±0.14 vs.1.00±0.09, P<0.05),but lower than those in the hyperoxia+Dex group(1.80±0.06 vs.3.61±0.19,2.10±0.10 vs.4.24±0.43, P<0.05).Western blot analysis revealed that the expression levels of PINK1 and Parkin in the hyperoxia injury group were higher than those in the air control group(2.16±0.11 vs.1.00±0.01,3.82±0.13 vs.1.00±0.01, P<0.05),but lower than those in the hyperoxia+Dex group(2.16±0.11 vs.3.35±0.14,3.82±0.13 vs.5.48±0.15, P<0.05).There were no significant differences in mitochondrial structure integrity,Complex Ⅰ enzyme activity,or the expression levels of PINK1 and Parkin,as assessed by qPCR and Western blot analysis,between the air control and Dex control groups( P>0.05). Conclusion:Dex effectively mitigates mitochondrial ultrastructural damage in BPD model mice,enhances the activity of Complex Ⅰ in the oxidative respiratory chain,reduces mitochondrial damage,and increases the activation of the PINK1-Parkin-mediated mitophagy pathway,thereby promoting lung protection.

Objective:To investigate the effects and underlying mechanism of ionizing radiation on the adipogenic of mesenchymal stem cells(MSCs).Methods:Mouse MSCs were cultured in vitro and treated with 2 Gy and 6 Gy radiation with 60Co,and the radiation dose rate was 0.98 Gy/min.Bulk RNA-seq was performed on control and irradiated MSCs.The changes of adipogenic differentiation and oxidative stress pathways of MSC were revealed by bioinformatics analysis.Oil Red O staining was used to detect the adipogenic differentiation ability of MSCs in vitro,and real-time fluorescence quantitative PCR(qPCR)was used to detect the expression differences of key regulatory factors Cebpa,Lpl and Pparg after radiation treatment.At the same time,qPCR and Western blot were used to detect the effect of inhibition of Nrf2,a key factor of antioxidant stress pathway,on the expression of key regulatory factors of adipogenesis.Moreover,the species conservation of the irradiation response of human bone marrow MSCs and mouse MSC was determined by qPCR.Results:Bulk RNA-seq suggested that ionizing radiation promotes adipogenic differentiation of MSCs and up-regulation of oxidative stress-related genes and pathways.The results of Oil Red O staining and qPCR showed that ionizing radiation promoted the adipogenesis of MSCs,with high expression of Cebpa,Lpl and Pparg,as well as oxidative stress-related gene Nrf2.Nrf2 pathway inhibitors could further enhance the adipogenesis of MSCs in bone marrow after radiation.Notably,the similar regulation of oxidative pathways and enhanced adipogenesis post irradiation were observed in human bone marrow MSCs.In addition,irradiation exposure led to up-regulated mRNA expression of interleukin-6 and down-regulated mRNA expression of colony stimulating factor 2 in human bone marrow MSCs.Conclusion:Ionizing radiation promotes adipogenesis of MSCs in mice,and oxidative stress pathway participates in this effect,blocking Nrf2 further promotes the adipogenesis of MSCs.Additionally,irradiation activates oxidative pathways and promotes adipogenic differentiation of human bone marrow MSCs.

Objective:To establish an in vitro cell model simulating acute graft-versus-host disease(aGVHD)bone marrow microenvironment injury with the advantage of mouse serum of aGVHD model and explore the effect of serum of aGVHD mouse on the adipogenic differentiation ability of mesenchymal stem cells(MSCs).Methods:The 6-8-week-old C57BL/6N female mice and BALB/c female mice were used as the donor and recipient mice of the aGVHD model,respectively.Bone marrow transplantation(BMT)mouse model(n=20)was established by being injected with bone marrow cells(1 × 10'per mouse)from donor mice within 4-6 hours after receiving a lethal dose(8.0 Gy,72.76 cGy/min)of y ray general irradiation.A mouse model of aGVHD(n=20)was established by infusing a total of 0.4 ml of a mixture of donor mouse-derived bone marrow cells(1 × 107 per mouse)and spleen lymphocytes(2 × 106 per mouse).The blood was removed from the eyeballs and the mouse serum was aspirated on the 7th day after modeling.Bone marrow-derived MSCs were isolated from 1-week-old C57BL/6N male mice and incubated with 2％,5％and 10％BMT mouse serum and aGVHD mouse serum in the medium,respectively.The effect of serum in the two groups on the in vitro adipogenic differentiation ability of mouse MSCs was detected by Oil Red O staining.The expression levels of related proteins PPARy and CEBPα were detected by Western blot.The expression differences of key adipogenic transcription factors including PPARy,CEBPα,FABP4 and LPL were determined by real-time quantitative PCR(RT-qPCR).Results:An in vitro cell model simulating the damage of bone marrow microenvironment in mice with aGVHD was successfully established.Oil Red O staining showed that the number of orange-red fatty droplets was significantly reduced and the adipogenic differentiation ability of MSC was impaired at aGVHD serum concentration of 10％compared with BMT serum.Western blot experiments showed that adipogenesis-related proteins PPARy and CEBPα expressed in MSCs were down-regulated.Further RT-qPCR assay showed that the production of PPARy,CEBPα,FABP4 and LPL,the key transcription factors for adipogenic differentiation of MSC,were significantly reduced.Conclusion:The adipogenic differentiation capacity of MSCs is inhibited by aGVHD mouse serum.

Objective:To analyze the expression levels and clinical significance of interferon (IFN)-α/β in the renal cortex and serum of children with lupus nephritis (LN).Methods:A total of 32 children with LN diagnosed in the pediatric nephrology department of the Second Xiangya Hospital of Central South University from December 2017 to September 2020 were selected as the study subjects (LN group). The normal kidney control group consisted of 3 normal kidney transplant volunteers who underwent biopsy of kidney tissue (normal kidney control group), while 14 healthy children who underwent physical examination were collected as the normal control group. According to the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), LN patients were divided into mild activity group ( n=8), moderate activity group ( n=9), and severe activity group ( n=15). According to the International Society of Nephrology/Society of Nephrology (ISN/RPS) 2003 LN classification criteria, pathological classification was performed (3 cases in the mild pathological damage group, 8 cases in the moderate pathological damage group, and 11 cases in the severe pathological damage group); Immunohistochemistry was used to detect the expression and distribution of IFN-α/β in glomeruli and renal interstitium; Enzyme linked immunosorbent assay (ELISA) was used to detect the concentration of IFN-α/β in serum samples and analyze its correlation with the pathological classification and disease activity of LN patients. Results:The serum and renal cortex IFN-α/β levels in the LN group were higher than those in the normal control group and normal kidney control group, respectively (all P<0.05). The average level of serum IFN-α/β in the heavy activity group was higher than that in the light and moderate activity groups (all P<0.05). The serum and renal cortex IFN-α/β levels in the severe pathological damage group were significantly higher than those in the mild and moderate pathological damage groups (all P<0.05). Conclusions:IFN-α/β in the renal cortex is closely related to renal injury in LN; Serum IFN-α/β can assist in evaluating the disease activity level of LN to a certain extent.