BACKGROUND:The mesenchymal stem cell secretome contains bioactive substances,cytokines,and growth factors.Three-dimensional cell culture can regulate the secretion of these components,potentially enhancing the ability to promote injury repair.OBJECTIVE:To investigate the repair effect of three-dimensional cultured human umbilical cord mesenchymal stem cell secretome on skin injuries in mice.METHODS:Human umbilical cord mesenchymal stem cells were cultured in conventional two-dimensional culture dishes and 96-well U-bottom cell culture plates,from which their secretory components were subsequently collected.The expression of skin damage repair related secretory factors in umbilical cord mesenchymal stem cells was analyzed using RT-qPCR.The protein expression level of skin damage repair related factors in umbilical cord mesenchymal stem cell secretome was detected using enzyme-linked immunosorbent assay.The potential of human umbilical cord mesenchymal stem cell secretome to repair vascular injuries was evaluated using an immortalized human umbilical vein endothelial cell migration model.A mouse skin injury model was established,and the human umbilical cord mesenchymal stem cell secretome was injected subcutaneously.Repair effects on skin injury were assessed through wound healing rates and histopathological analysis.RESULTS AND CONCLUSION:(1)After three days of cultivation,human umbilical cord mesenchymal stem cells cultured in two dimensions exhibited a fibroblast-like,swirling growth pattern,whereas three-dimensional culture led to the formation of uniform microspheres.(2)Compared with two-dimensional culture,three-dimensional culture significantly increased the mRNA expression of transforming growth factor β and basic fibroblast growth factor in human umbilical cord mesenchymal stem cells.(3)Compared with two-dimensional culture,three-dimensional cultured human umbilical cord mesenchymal stem cell secretome significantly enhanced the protein expression of vascular endothelial growth factor,interleukin-10,and granulocyte-macrophage colony-stimulating factor in the human umbilical cord mesenchymal stem cell secretome.(4)Compared with two-dimensional culture,three-dimensional cultured human umbilical cord mesenchymal stem cell secretome significantly promoted the migration of immortalized human umbilical cord mesenchymal stem cells.(5)Compared with the untreated control group and the two-dimensional cultured human umbilical cord mesenchymal stem cell secretome,the three-dimensional cultured human umbilical cord mesenchymal stem cell secretome can significantly accelerate the skin wound healing rate and wound skin structure remodeling in mice.These results indicate that three-dimensional culture can enhance the expression of paracrine factors of human umbilical cord mesenchymal stem cells,and their secretome can significantly promote the repair of mouse skin damage.

BACKGROUND:The mesenchymal stem cell secretome contains bioactive substances,cytokines,and growth factors.Three-dimensional cell culture can regulate the secretion of these components,potentially enhancing the ability to promote injury repair.OBJECTIVE:To investigate the repair effect of three-dimensional cultured human umbilical cord mesenchymal stem cell secretome on skin injuries in mice.METHODS:Human umbilical cord mesenchymal stem cells were cultured in conventional two-dimensional culture dishes and 96-well U-bottom cell culture plates,from which their secretory components were subsequently collected.The expression of skin damage repair related secretory factors in umbilical cord mesenchymal stem cells was analyzed using RT-qPCR.The protein expression level of skin damage repair related factors in umbilical cord mesenchymal stem cell secretome was detected using enzyme-linked immunosorbent assay.The potential of human umbilical cord mesenchymal stem cell secretome to repair vascular injuries was evaluated using an immortalized human umbilical vein endothelial cell migration model.A mouse skin injury model was established,and the human umbilical cord mesenchymal stem cell secretome was injected subcutaneously.Repair effects on skin injury were assessed through wound healing rates and histopathological analysis.RESULTS AND CONCLUSION:(1)After three days of cultivation,human umbilical cord mesenchymal stem cells cultured in two dimensions exhibited a fibroblast-like,swirling growth pattern,whereas three-dimensional culture led to the formation of uniform microspheres.(2)Compared with two-dimensional culture,three-dimensional culture significantly increased the mRNA expression of transforming growth factor β and basic fibroblast growth factor in human umbilical cord mesenchymal stem cells.(3)Compared with two-dimensional culture,three-dimensional cultured human umbilical cord mesenchymal stem cell secretome significantly enhanced the protein expression of vascular endothelial growth factor,interleukin-10,and granulocyte-macrophage colony-stimulating factor in the human umbilical cord mesenchymal stem cell secretome.(4)Compared with two-dimensional culture,three-dimensional cultured human umbilical cord mesenchymal stem cell secretome significantly promoted the migration of immortalized human umbilical cord mesenchymal stem cells.(5)Compared with the untreated control group and the two-dimensional cultured human umbilical cord mesenchymal stem cell secretome,the three-dimensional cultured human umbilical cord mesenchymal stem cell secretome can significantly accelerate the skin wound healing rate and wound skin structure remodeling in mice.These results indicate that three-dimensional culture can enhance the expression of paracrine factors of human umbilical cord mesenchymal stem cells,and their secretome can significantly promote the repair of mouse skin damage.

Objective:To investigate the drug resistance gene characteristics, plasmid characteristics and genome tracing of Shigella sonnei causing a bacillary dysentery outbreak in Shandong Province. Methods:Sixty-five Shigella sonnei strains isolated from a 2021 outbreak in a county of Shandong Province were analyzed using antimicrobial susceptibility testing, whole genome sequencing (WGS), characterization of resistance and virulence genes, plasmid profiling, core genome multilocus sequence typing (cgMLST), and single nucleotide polymorphism (SNP) analysis. Results:All isolates had the same resistance phenotype and genotypes and were multidrug-resistant ESBL-producing Shigella sonnei, carrying important virulence genes. Plasmid analysis revealed a conserved genetic arrangement, pil( M/ N/ O2/ P)-tra( F/ H/ J/ K/ N/ O/ P/ Q)-IS Ecp1- blaCTX-M-14-Tn 903- yub( J/ I/ F/ G/ E/ D), and shared across strains from diverse regions and bacterial species. The cgMLST and SNP analyses demonstrated concordant clustering, with all 65 outbreak-related strains forming a single cluster alongside human-derived strains from Guangxi. Conclusion:The ESBL-producing Shigella sonnei responsible for the outbreak shares a homologous relationship with Guangxi human-derived strains, and the detected resistance plasmids and virulence genes underscore the need to strengthen drug resistance surveillance and genome tracing.

Tuberculosis is a zoonotic disease posing a substantial public health threat.Immunological diagnosis and vaccine im-munization are both necessary to control tuberculosis prevalence.However,the identical antigenic components in diagnostic reagents and vaccines hinder the use of animal vaccines and limit the specificity of clinical diagnosis in humans.Differentiating infected from vaccinated animals can overcome these problems.This article reviews the progress in differential diagnosis research from three as-pects:the diagnostic effects of antigens,methods for discovering new antigens,and screening of new host immune markers,to provide a theoretical basis for future research.

Tuberculosis is a zoonotic disease posing a substantial public health threat.Immunological diagnosis and vaccine im-munization are both necessary to control tuberculosis prevalence.However,the identical antigenic components in diagnostic reagents and vaccines hinder the use of animal vaccines and limit the specificity of clinical diagnosis in humans.Differentiating infected from vaccinated animals can overcome these problems.This article reviews the progress in differential diagnosis research from three as-pects:the diagnostic effects of antigens,methods for discovering new antigens,and screening of new host immune markers,to provide a theoretical basis for future research.

Objective:To investigate the drug resistance gene characteristics, plasmid characteristics and genome tracing of Shigella sonnei causing a bacillary dysentery outbreak in Shandong Province. Methods:Sixty-five Shigella sonnei strains isolated from a 2021 outbreak in a county of Shandong Province were analyzed using antimicrobial susceptibility testing, whole genome sequencing (WGS), characterization of resistance and virulence genes, plasmid profiling, core genome multilocus sequence typing (cgMLST), and single nucleotide polymorphism (SNP) analysis. Results:All isolates had the same resistance phenotype and genotypes and were multidrug-resistant ESBL-producing Shigella sonnei, carrying important virulence genes. Plasmid analysis revealed a conserved genetic arrangement, pil( M/ N/ O2/ P)-tra( F/ H/ J/ K/ N/ O/ P/ Q)-IS Ecp1- blaCTX-M-14-Tn 903- yub( J/ I/ F/ G/ E/ D), and shared across strains from diverse regions and bacterial species. The cgMLST and SNP analyses demonstrated concordant clustering, with all 65 outbreak-related strains forming a single cluster alongside human-derived strains from Guangxi. Conclusion:The ESBL-producing Shigella sonnei responsible for the outbreak shares a homologous relationship with Guangxi human-derived strains, and the detected resistance plasmids and virulence genes underscore the need to strengthen drug resistance surveillance and genome tracing.

Objective:To investigate the drug resistance status and genomic characterization of Proteus mirabilis (PM) isolated from outpatient cases with diarrhea in Tai′an City and Laizhou City, Shandong Province. Methods:A total of 510 fecal samples were collected from 510 patients with acute diarrhea admitted to 43 sentinel hospitals in Tai′an City and Laizhou City, Shandong Province, between January 2021 and December 2022. The samples were cultured and isolated to identify Proteus spp. by direct inoculation, the drug susceptibility testing was performed by microbroth dilution method, and resistance genes and virulence genes were obtained by whole genome sequencing and bioinformatic analysis, thereby revealing the genetic environment surrounding the blaOXA-1 and blaCTX-M-65 genes. Single nucleotide polymorphism (SNP) analysis and core genome multilocus sequence typing (cgMLST) were conducted on the current strains and 100 PM isolates downloaded from the National Center for Biotechnology Information (NCBI) database via customizable methods utilizing RidomSeqSphere+ software, with the objective of exploring the phylogenetic relationships among the strains. Results:A total of 35 strains of Proteus were isolated from 510 fecal samples, including 31 strains of PM with a detection rate of 6.08% (31/510) and four strains of Proteus vulgaris.The multidrug resistance rate of PM was 100.00% (31/31).The 35 isolates carried a total of 43 resistance genotypes.Thirteen strains of PM carried blaOXA-1, six strains carried both blaOXA-1 and blaCTX-M-65, and 15 PM strains carried at least 15 antibiotic resistance genes (ARGs). The virulence genes included ureA, mrpA, ZapA, hpmA and so on. blaOXA-1 and blaCTX-M-65 genes were surrounded by mobile elements such as Tn3, ISL3 and IS6. cgMLST showed consistency with the SNP clustering results. Isolate 2022LZ41 from Laizhou City clustered with isolates 2022TA018, 2022TA017 and 2022TA019 from Tai′an City, with the number of allelic differences ranging from zero to two, and the Laizhou City isolate 2022LZ40 was highly genetically related to strain CRK0056 (human, USA, 2015). Conclusions:PM isolated from patients with diarrhea is multidrug-resistant, carrying many resistance and virulence genes.The presence of mobile genetic elements can lead to horizontal transfer of resistance genes.

Objective To investigate the risk factors for multiple organ dysfunction syndrome(MODS)in elderly patients with severe stroke.Methods A total of 112 elderly severe stroke pa-tients admitted to our hospital from January 2020 to December 2022 were recruited prospectively,and then according to the results of sequential organ failure assessment(SOFA)within 14 d after admission,they were divided into MODS group(n=38)and non-MODS group(n=74).Based on their clinical outcomes,they were also assigned into survival group(n=-33)and death group(n=79).General clinical data,acute physiology,chronic health evaluationⅡ(APACHEⅡ)score,Glas-gow coma scale(GCS)score,and head computed tomography parameters were collected.Logistic regression analysis was used to analyze the risk factors of MODS.Results The MODS group had significantly larger proportions of stroke/hemorrhage,chronic obstructive pulmonary disease,cor-onary heart disease and smoking,higher NIHSS and APACHE Ⅱ scores,elevated ratios of multi-vessel disease,urinary tract infection,venous thrombosis,hemorrhage,epilepsy and myocardial in-farction,more patients using acute mechanical ventilation and osmotic therapy,and increased hos-pital mortality,but lower GCS score when compared with the non-MODS group(P＜0.05,P＜0.01).Binary logistic regression analysis showed that NIHSS score,APACHE Ⅱ score,and mul-tivessel disease were independent risk factors for MODS(OR=1.124,95％CI:1.121-1.163,P=0.015;OR=1.265,95％CI:1.296-1.426,P=0.001;OR=2.532,95％CI:1.126-5.013,P=0.026).The MODS score and APACHE Ⅱ score were significantly higher in the death group than the survival group(P＜0.05).Conclusion Elderly severe stroke patients are prone to MODS during the acute period.

OBJECTIVE To explore the role of Yes-associated protein(YAP)in epidermal stem cell(EPSC)differentiation after ionizing radiation(IR).METHODS ① A punch was used to induce skin injuries on the back of mice.The IR group received localized irradiation with 60 Co γ-rays,while the normal control group did not.Samples were collected at 0,1,3,6,9,and 12 d for RNA and protein extraction.Western blotting was used to detect changes in YAP protein expressions during wound healing.Real-time quantitative polymerase chain reaction(RT-qPCR)was performed to assess the mRNA levels of Yap and its downstream target genes,connective tissue growth factor(Ctgf),and cysteine-rich protein 61(Cyr61).② EPSCs were exposed to 60 Co γ at a dose of 4 or 8 Gy,while the control group was not irradiated.Cells were collected to detect the levels of YAP protein via Western blotting.Cells were collected at 4,12,24,and 36 h post-IR to assess the levels of YAP mRNA by RT-qPCR.③ Short hairpin RNA(shRNA)was used to establish stable YAP knockdown cell lines,and the knockdown efficiency of sh YAP was verified by Western blotting.RT-qPCR was then performed to detect the impact of YAP knockdown on mRNA levels of K1 and K10 after IR.RESULTS① Compared with the control group,the YAP protein level in the IR group during wound healing was significantly reduced(P<0.05,P<0.01),so were the mRNA levels of Yap and its downstream target genes Ctgf and Cyr61(P<0.05,P<0.01).② Compared to the cell control group,the mRNA and protein levels of YAP in the IR group cells were significantly reduced(P<0.01).③ In the sh YAP cells,the YAP protein level was significantly reduced(P<0.01).Furthermore,the mRNA levels of K1 and K10 were significantly decreased after IR in sh YAP cells(P<0.01).CONCLUSION YAP can regulate EPSC differentiation in wound healing after IR.