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 analyze the epidemiological, etiological and genetic characteristics of influenza virus in Shandong Province during 2023-2024.Methods:The surveillance data of influenza-like illness (ILI) in sentinel hospitals in Shandong from 2023 to 2024 were collected and analyzed. The isolated influenza strains with hemagglutination titers ≥8 were selected for antigenicity analysis, drug susceptibility test, gene sequencing and evolutionary analysis.Results:From 2023 to 2024, the positive rate of influenza virus in Shandong was 8.51% (23 663/277 995), the highest positive rate was in the age group of 5-14 years (15.78%, 6 073/38 478), and the highest positive rate was in the 49 th week (35.86%, 2 264/6 313). Both antigenicity analysis and evolutionary analysis showed that the A(H1N1)pdm09 subtype and B(Victoria) strain had good matching effect and close evolutionary distance with the 2023-2024 surveillance year vaccine strain. The A(H3N2) subtype strain did not have a high matching effect with the 2023-2024 vaccine strain and had a long evolutionary distance, but had a close evolutionary distance with the 2024-2025 vaccine strain. Drug susceptibility test showed that oseltamivir sensitivity of influenza A(H1N1)pdm09 strain decreased greatly, and the amino acid site mutation of neuraminidase was H275Y. Conclusions:In the 2023-2024 surveillance year, the peak of influenza virus epidemic in Shandong was mainly occurred in winter and spring, and the age group of 5-14 years was the focus of prevention and control. The dominant strain was subtype A(H3N2), which had poor matching effect with the vaccine strain in the 2023-2024 surveillance year. One A(H1N1)pdm09 resistant strain was found in the drug resistance monitoring work. Follow-up prevention and control work should be strengthen the surveillance for the epidemiological characteristics, genetic variation and drug resistance of influenza viruses, timely understand the epidemic trend and mutation of influenza viruses, timely discover drug-resistant strains of influenza viruses, promote influenza vaccination, and improve of influenza prevention and control.

Objective:To analyze the epidemiological, etiological and genetic characteristics of influenza virus in Shandong Province during 2023-2024.Methods:The surveillance data of influenza-like illness (ILI) in sentinel hospitals in Shandong from 2023 to 2024 were collected and analyzed. The isolated influenza strains with hemagglutination titers ≥8 were selected for antigenicity analysis, drug susceptibility test, gene sequencing and evolutionary analysis.Results:From 2023 to 2024, the positive rate of influenza virus in Shandong was 8.51% (23 663/277 995), the highest positive rate was in the age group of 5-14 years (15.78%, 6 073/38 478), and the highest positive rate was in the 49 th week (35.86%, 2 264/6 313). Both antigenicity analysis and evolutionary analysis showed that the A(H1N1)pdm09 subtype and B(Victoria) strain had good matching effect and close evolutionary distance with the 2023-2024 surveillance year vaccine strain. The A(H3N2) subtype strain did not have a high matching effect with the 2023-2024 vaccine strain and had a long evolutionary distance, but had a close evolutionary distance with the 2024-2025 vaccine strain. Drug susceptibility test showed that oseltamivir sensitivity of influenza A(H1N1)pdm09 strain decreased greatly, and the amino acid site mutation of neuraminidase was H275Y. Conclusions:In the 2023-2024 surveillance year, the peak of influenza virus epidemic in Shandong was mainly occurred in winter and spring, and the age group of 5-14 years was the focus of prevention and control. The dominant strain was subtype A(H3N2), which had poor matching effect with the vaccine strain in the 2023-2024 surveillance year. One A(H1N1)pdm09 resistant strain was found in the drug resistance monitoring work. Follow-up prevention and control work should be strengthen the surveillance for the epidemiological characteristics, genetic variation and drug resistance of influenza viruses, timely understand the epidemic trend and mutation of influenza viruses, timely discover drug-resistant strains of influenza viruses, promote influenza vaccination, and improve of influenza prevention and control.

Objective:To analyze the respiratory virus infection status and epidemiological characteristics of influenza-like illness (ILI) cases in Shandong Province during the 2020 -2021 influenza surveillance year. Methods:According to the National Influenza Surveillance Plan (2017 version), throat swab samples of ILI cases were collected from 14 surveillance sentinel hospitals in Shandong Province. Nucleic acid was extracted from all samples. Real-time fluorescence quantitative PCR (RT-PCR) was utilized to detect six common viruses, including human metapneumovirus (HMPV), human parainfluenza virus (HPIV) types 1, 2 and 3, respiratory syncytial virus (RSV), and adenovirus (ADV). Subsequently, the obtained detection results were analyzed.Results:A total of 2 386 specimens were collected, with a detection rate of 24.22% (578). Six viruses were detected, with detection rates of 6.75% (162 cases) for HMPV, 5.87% (140 cases) for RSV, 3.56% (85 cases) for HPIV3, 3.14% (75 cases) for HPIV2, 2.98% (71 cases) for HPIV1, and 2.77% (66 cases) for ADV. There was no significant difference in detection rates between genders, but a notable variation among different age groups ( P<0.001). The highest detection rate was observed in individuals aged 0-4 years (31.94%), followed by those aged≥60 years (26.06%). The prevalence of six viruses showed a monthly variation, with the detection rate of HMPV being higher in December and HPIV1 being higher in February. HPIV2, HPIV3, RSV, and ADV had higher detection rates in November. The co-detection rate of multiple viruses was 0.80%, with RSV being the most common pathogen involved in co-detection, primarily in individuals aged 0-4 years. Conclusion:The detection of six multiple pathogens in ILI cases in Shandong Province is dominated by HMPV, RSV and HPIV3. The prevalence of respiratory viruses varies by age and time.

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 analyze the situation of rodents carrying Hantavirus and the genetic and evolutionary characteristics of the virus in Zibo city, Shandong province in 2022, and provide reference for the scientific prevention and control of hemorrhagic fever with renal syndrome (HFRS).Methods:Real-time quantitative PCR (RT-qPCR) was used to detect hantavirus (HV) nucleic acids in rodent lung tissues and identify HV genotypes. Each nucleic acid fragment was designed to amplify various gene fragments by segment, and the whole genome of Hantavirus was sequenced by second generation sequencing. Sequence assembly was performed using SeqMan 7.1.0.44, a subprogram of DNAStar. Sequence alignment and evolutionary analysis were conducted using MEGA 7.0 and BioEdit software.Results:A total of 270 host animals were captured in this survey. Among them, 13 rodent lung samples tested positive for Hantavirus, resulting in a virus-positive rate of 4.8%. The full-genome sequences of four hantavirus strains were successfully obtained, all identified as Seoul virus (SEOV) genotype. Four Hantavirus-positive samples showed high nucleotide sequence homology in the M gene and belonged to the SEOV S3 subtype. These strains exhibited high similarity with those from Hebei, Liaoning, and Beijing. The amino acid sequences of the nucleoprotein and glycoprotein immunogenic epitopes were identical to those of the vaccine strain Z37.Conclusions:This study successfully determined the full genome sequences of four hantavirus strains from Zibo city, Shandong province. The genotypes are primarily SEOV, with the subtype being S3. The homology of genes within the same subtype is high, with no significant variations observed. The alignment of immune epitopes in key proteins suggests that the current vaccine may provide protection against locally circulating strains, but further in-depth research is still required.

Objective:To analyze the respiratory virus infection status and epidemiological characteristics of influenza-like illness (ILI) cases in Shandong Province during the 2020 -2021 influenza surveillance year. Methods:According to the National Influenza Surveillance Plan (2017 version), throat swab samples of ILI cases were collected from 14 surveillance sentinel hospitals in Shandong Province. Nucleic acid was extracted from all samples. Real-time fluorescence quantitative PCR (RT-PCR) was utilized to detect six common viruses, including human metapneumovirus (HMPV), human parainfluenza virus (HPIV) types 1, 2 and 3, respiratory syncytial virus (RSV), and adenovirus (ADV). Subsequently, the obtained detection results were analyzed.Results:A total of 2 386 specimens were collected, with a detection rate of 24.22% (578). Six viruses were detected, with detection rates of 6.75% (162 cases) for HMPV, 5.87% (140 cases) for RSV, 3.56% (85 cases) for HPIV3, 3.14% (75 cases) for HPIV2, 2.98% (71 cases) for HPIV1, and 2.77% (66 cases) for ADV. There was no significant difference in detection rates between genders, but a notable variation among different age groups ( P<0.001). The highest detection rate was observed in individuals aged 0-4 years (31.94%), followed by those aged≥60 years (26.06%). The prevalence of six viruses showed a monthly variation, with the detection rate of HMPV being higher in December and HPIV1 being higher in February. HPIV2, HPIV3, RSV, and ADV had higher detection rates in November. The co-detection rate of multiple viruses was 0.80%, with RSV being the most common pathogen involved in co-detection, primarily in individuals aged 0-4 years. Conclusion:The detection of six multiple pathogens in ILI cases in Shandong Province is dominated by HMPV, RSV and HPIV3. The prevalence of respiratory viruses varies by age and time.

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.