Collagen is a major structural protein in the matrix of animal cells and the most widely distributed and abundant functional protein in mammals. Collagen’s good biocompatibility, biodegradability and biological activity make it a very valuable biomaterial. According to the source of collagen, it can be broadly categorized into two types: one is animal collagen; the other is recombinant collagen. Animal collagen is mainly extracted and purified from animal connective tissues by chemical methods, such as acid, alkali and enzyme methods, etc. Recombinant collagen refers to collagen produced by gene splicing technology, where the amino acid sequence is first designed and improved according to one’s own needs, and the gene sequence of improved recombinant collagen is highly consistent with that of human beings, and then the designed gene sequence is cloned into the appropriate vector, and then transferred to the appropriate expression vector. The designed gene sequence is cloned into a suitable vector, and then transferred to a suitable expression system for full expression, and finally the target protein is obtained by extraction and purification technology. Recombinant collagen has excellent histocompatibility and water solubility, can be directly absorbed by the human body and participate in the construction of collagen, remodeling of the extracellular matrix, cell growth, wound healing and site filling, etc., which has demonstrated significant effects, and has become the focus of the development of modern biomedical materials. This paper firstly elaborates the structure, type, and tissue distribution of human collagen, as well as the associated genetic diseases of different types of collagen, then introduces the specific process of producing animal source collagen and recombinant collagen, explains the advantages of recombinant collagen production method, and then introduces the various systems of expressing recombinant collagen, as well as their advantages and disadvantages, and finally briefly introduces the application of animal collagen, focusing on the use of animal collagen in the development of biopharmaceutical materials. In terms of application, it focuses on the use of animal disease models exploring the application effects of recombinant collagen in wound hemostasis, wound repair, corneal therapy, female pelvic floor dysfunction (FPFD), vaginal atrophy (VA) and vaginal dryness, thin endometritis (TE), chronic endometritis (CE), bone tissue regeneration in vivo, cardiovascular diseases, breast cancer (BC) and anti-aging. The mechanism of action of recombinant collagen in the treatment of FPFD and CE was introduced, and the clinical application and curative effect of recombinant collagen in skin burn, skin wound, dermatitis, acne and menopausal urogenital syndrome (GSM) were summarized. From the exploratory studies and clinical applications, it is evident that recombinant collagen has demonstrated surprising effects in the treatment of all types of diseases, such as reducing inflammation, promoting cell proliferation, migration and adhesion, increasing collagen deposition, and remodeling the extracellular matrix. At the end of the review, the challenges faced by recombinant collagen are summarized: to develop new recombinant collagen types and dosage forms, to explore the mechanism of action of recombinant collagen, and to provide an outlook for the future development and application of recombinant collagen.

Umbilical cord mesenchymal stem cells (UC-MSCs) have been widely used in regenerative medicine, but there is limited research on the stability of UC-MSCs formulation during production. This study aims to assess the stability of the cell stock solution and intermediate product throughout the production process, as well as the final product following reconstitution, in order to offer guidance for the manufacturing process and serve as a reference for formulation reconstitution methods. Three batches of cell formulation were produced and stored under low temperature (2-8 ℃) and room temperature (20-26 ℃) during cell stock solution and intermediate product stages. The storage time intervals for cell stock solution were 0, 2, 4, and 6 h, while for intermediate products, the intervals were 0, 1, 2, and 3 h. The evaluation items included visual inspection, viable cell concentration, cell viability, cell surface markers, lymphocyte proliferation inhibition rate, and sterility. Additionally, dilution and culture stability studies were performed after reconstitution of the cell product. The reconstitution diluents included 0.9% sodium chloride injection, 0.9% sodium chloride injection + 1% human serum albumin, and 0.9% sodium chloride injection + 2% human serum albumin, with dilution ratios of 10-fold and 40-fold. The storage time intervals after dilution were 0, 1, 2, 3, and 4 h. The reconstitution culture media included DMEM medium, DMEM + 2% platelet lysate, 0.9% sodium chloride injection, and 0.9% sodium chloride injection + 1% human serum albumin, and the culture duration was 24 h. The evaluation items were viable cell concentration and cell viability. The results showed that the cell stock solution remained stable for up to 6 h under both low temperature (2-8 ℃) and room temperature (20-26 ℃) conditions, while the intermediate product remained stable for up to 3 h under the same conditions. After formulation reconstitution, using sodium chloride injection diluted with 1% or 2% human serum albumin maintained a viability of over 80% within 4 h. It was observed that different dilution factors had an impact on cell viability. After formulation reconstitution, cultivation in medium with 2% platelet lysate resulted in a cell viability of over 80% after 24 h. In conclusion, the stability of cell stock solution within 6 h and intermediate product within 3 h meets the requirements. The addition of 1% or 2% human serum albumin in the reconstitution diluent can better protect the post-reconstitution cell viability.

Rapid epidemiological screening for tuberculosis (TB) usually uses tuberculin pure protein derivative (PPD) skin test, which has limitations such as low specificity and high side effects. ESAT-6 and CFP-10 are secreted proteins of Mycobacterium tuberculosis, but the related genes are missing from Bacillus Calmette-Guerin (BCG). In this study, the fusion protein ESAT6-CFP10 (EC) was expressed and purified, and prepared into chitosan nanoparticles (EC-NPs), which were loaded into the microneedle patch and carried out the preliminary test of tuberculosis skin test. The drug loading capacity of MNP-EC-NPs (microneedle patch, MNP) can reach 0.03 μg per needle and 1.92 μg per patch. The shelf life of MNP-EC-NPs can reach 6 months at room temperature, and it can effectively penetrate the epidermis. Volunteer skin test results showed that MNP-EC-NPs can effectively distinguish between BCG vaccinators, and can effectively show positive reaction in the skin of tuberculosis patients without significant side effects. The experiment was approved by the Ethics Committee of Wuhan Pulmonary Hospital [2022 (2)]. In this study, a TB skin test method was established, using ESAT6-CFP10 fusion protein instead of PPD, and using soluble microneedle dosage form, which improved the specificity of TB skin test diagnosis and provided a new technical scheme for TB epidemic screening.

Objective:To evaluate the efficacy and safety of hypomethylating agents (HMA) in patients with myelodysplastic syndromes (MDS) .Methods:A total of 409 MDS patients from 45 hospitals in Zhejiang province who received at least four consecutive cycles of HMA monotherapy as initial therapy were enrolled to evaluate the efficacy and safety of HMA. Mann-Whitney U or Chi-square tests were used to compare the differences in the clinical data. Logistic regression and Cox regression were used to analyze the factors affecting efficacy and survival. Kaplan-Meier was used for survival analysis. Results:Patients received HMA treatment for a median of 6 cycles (range, 4-25 cycles) . The complete remission (CR) rate was 33.98% and the overall response rate (ORR) was 77.02%. Multivariate analysis revealed that complex karyotype ( P=0.02, OR=0.39, 95% CI 0.18-0.84) was an independent favorable factor for CR rate. TP53 mutation ( P=0.02, OR=0.22, 95% CI 0.06-0.77) was a predictive factor for a higher ORR. The median OS for the HMA-treated patients was 25.67 (95% CI 21.14-30.19) months. HMA response ( P=0.036, HR=0.47, 95% CI 0.23-0.95) was an independent favorable prognostic factor, whereas complex karyotype ( P=0.024, HR=2.14, 95% CI 1.10-4.15) , leukemia transformation ( P<0.001, HR=2.839, 95% CI 1.64-4.92) , and TP53 mutation ( P=0.012, HR=2.19, 95% CI 1.19-4.07) were independent adverse prognostic factors. There was no significant difference in efficacy and survival between the reduced and standard doses of HMA. The CR rate and ORR of MDS patients treated with decitabine and azacitidine were not significantly different. The median OS of patients treated with decitabine was longer compared with that of patients treated with azacitidine (29.53 months vs 20.17 months, P=0.007) . The incidence of bone marrow suppression and pneumonia in the decitabine group was higher compared with that in the azacitidine group. Conclusion:Continuous and regular use of appropriate doses of hypomethylating agents may benefit MDS patients to the greatest extent if it is tolerated.

Surface-enhanced Raman scattering(SERS)can detect molecules adsorbed on the surface of noble metals in monolayers and sub-monolayers,and provide structural information of molecules with high sensitivity,high accuracy,and fingerprint recognition and non-destructive detection.The SERS technology has been widely used in single-molecule detection,chemical reaction and engineering,biomedicine,nanomaterials and environmental detection,and so on.The spectral sensitivity and signal reproducibility of SERS are closely related to the type of noble metal substrate.In this paper,based on the mechanism of electromagnetic field enhancement(EM)and chemical enhancement(CM)of SERS,the affecting factors of SERS enhancement were analyzed,including the micro-nanostructure of SERS substrate,particle size,particle spacing,etc,the research and application of SERS substrate in recent years were summarized and reviewed,and the development direction of metal substrate,data analysis and application direction of SERS technology in the future were prospected.

Objective To investigate the role and underlying mechanisms of miR-34a/SIRT1 in intensive care unit acquired weakness(ICU-AW).Methods(1)C2C12 mouse skeletal muscle cells were induced to differentiate into myotubes,and were divided into two groups:model group[ICU-AW group,treated with lipopolysaccharides(LPS)for 12 hours]and normal control group(treated with the same amount of sterile water for 12 hours).Western blotting was used to detect the protein expression level of Muscle ring finger 1(MuRF-1),atrophy gene 1(Atrogin-1)and Sirtuin-1(SIRT1).RT-qPCR was used to assess the mRNA expression level of microRNA-34a(miR-34a),MuRF-1,Atrogin-1 and SIRT1,and light microscope was used to observe the growth and differentiation of C2C12 skeletal muscle cells in each group.(2)ICU-AW cells were further subdivided into control group(treated with siRNA transfection agent intervention),Scra siRNA group(treated with transfection agent and non-specific siRNA),miR-34a siRNA group(treated with transfection agent and specific siRNA intervention),vehicle group(treated with agonist solvent dimethyl sulfoxide)and SRT1720 group(treated with SIRT1 agonist SRT1720).Western blotting was used to detect the protein expression level of SIRT1,Atrogin-1 and MuRF-1 in each group.RT-qPCR was used to detect the miR-34a and the mRNA expression level of SIRT1,Atrogin-1 and MuRF-1 in each group.(3)In addition,another group of ICU-AW cells were divided into control group(treated with siRNA transfection),miR-34a siRNA group(treated with transfection agent and specific siRNA intervention),miR-34a siRNA+vehicle group(treated with transfection agent,specific siRNA and Dimethyl sulfoxide intervention)and miR-34a siRNA+EX-527 group(treated with transfection agent,specific siRNA and SIRT1 inhibitor EX-527).Western blotting was used to detect the protein expression level of Atrogin-1 and MuRF-1.RT-qPCR was used to assess the mRNA expression level of Atrogin-1 and MuRF-1.Results Myotube differentiation was observed on the 4th day.Compared with control group,myotube atrophy was obvious in ICU-AW group.RT-qPCR and Western blotting results revealed that,compared with normal control group,in ICU-AW group,the mRNA and protein expression levels of Atrogin-1 and MuRF-1 significantly increased(P＜0.05),and the expression level of miR-34a significantly increased(P＜0.05),while the mRNA and protein expression levels of SIRT1 significantly decreased(P＜0.05).RT-qPCR results showed that,compared with control group(treated with siRNA transfection agent intervention)and Scra siRNA group,the expression of miR-34a and mRNA expression of Atrogin-1 and MuRF-1 in miR-34a siRNA group significantly decreased(P＜0.05),while the mRNA expression of SIRT1 significantly increased(P＜0.05),meanwhile the protein expression of Atrogin-1 and MuRF-1 decreased significantly(P＜0.01),and the protein expression of SIRT1 significantly increased(P＜0.05).RT-qPCR results also showed that,compared with vehicle group,the mRNA expression of Atrogin-1 and MuRF-1 in SRT1720 group decreased significantly(P＜0.05),while SIRT1 increased significantly(P＜0.05).Western blotting results demonstrated that,compared with control group and Scra siRNA group,the protein expression of Atrogin-1 and MuRF-1 in miR-34a siRNA group decreased significantly(P＜0.05),while SIRT1 increased significantly(P＜0.05).RT-qPCR and Western blotting results indicated that,compared with miR-34a siRNA+vehicle group,the mRNA and protein expression of Atrogin-1 and MuRF-1 in miR-34a siRNA+EX-527 group increased significantly(P＜0.05).Conclusion Overactivation of miR-34a in ICU-AW contributes to skeletal muscle atrophy by inhibiting the expression of SIRT1,which may play an important role in the pathogenesis of ICU-AW.

Objective To investigate the clinical characteristics and prognosis of pneumococcal meningitis(PM),and drug sensitivity of Streptococcus pneumoniae(SP)isolates in Chinese children.Methods A retrospective analysis was conducted on clinical information,laboratory data,and microbiological data of 160 hospitalized children under 15 years old with PM from January 2019 to December 2020 in 33 tertiary hospitals across the country.Results Among the 160 children with PM,there were 103 males and 57 females.The age ranged from 15 days to 15 years,with 109 cases(68.1% )aged 3 months to under 3 years.SP strains were isolated from 95 cases(59.4% )in cerebrospinal fluid cultures and from 57 cases(35.6% )in blood cultures.The positive rates of SP detection by cerebrospinal fluid metagenomic next-generation sequencing and cerebrospinal fluid SP antigen testing were 40% (35/87)and 27% (21/78),respectively.Fifty-five cases(34.4% )had one or more risk factors for purulent meningitis,113 cases(70.6% )had one or more extra-cranial infectious foci,and 18 cases(11.3% )had underlying diseases.The most common clinical symptoms were fever(147 cases,91.9% ),followed by lethargy(98 cases,61.3% )and vomiting(61 cases,38.1% ).Sixty-nine cases(43.1% )experienced intracranial complications during hospitalization,with subdural effusion and/or empyema being the most common complication[43 cases(26.9% )],followed by hydrocephalus in 24 cases(15.0% ),brain abscess in 23 cases(14.4% ),and cerebral hemorrhage in 8 cases(5.0% ).Subdural effusion and/or empyema and hydrocephalus mainly occurred in children under 1 year old,with rates of 91% (39/43)and 83% (20/24),respectively.SP strains exhibited complete sensitivity to vancomycin(100% ,75/75),linezolid(100% ,56/56),and meropenem(100% ,6/6).High sensitivity rates were also observed for levofloxacin(81% ,22/27),moxifloxacin(82% ,14/17),rifampicin(96% ,25/26),and chloramphenicol(91% ,21/23).However,low sensitivity rates were found for penicillin(16% ,11/68)and clindamycin(6% ,1/17),and SP strains were completely resistant to erythromycin(100% ,31/31).The rates of discharge with cure and improvement were 22.5% (36/160)and 66.2% (106/160),respectively,while 18 cases(11.3% )had adverse outcomes.Conclusions Pediatric PM is more common in children aged 3 months to under 3 years.Intracranial complications are more frequently observed in children under 1 year old.Fever is the most common clinical manifestation of PM,and subdural effusion/emphysema and hydrocephalus are the most frequent complications.Non-culture detection methods for cerebrospinal fluid can improve pathogen detection rates.Adverse outcomes can be noted in more than 10% of PM cases.SP strains are high sensitivity to vancomycin,linezolid,meropenem,levofloxacin,moxifloxacin,rifampicin,and chloramphenicol.[Chinese Journal of Contemporary Pediatrics,2024,26(2):131-138]

This study was aimed at analyzing the changes in the cell proteome of HTR-8/Svneo human villous trophoblasts during infection with Listeria monocytogenes,to explore the mechanisms involved in L.monocytogenes infection of the placenta at the molecular level in host cells.Tandem Mass Tag(TMT)proteomics was used to compare the quantitative proteome be-tween the HTR-8/Svneo infection group and control group.The Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)databases were used to analyze enrichment in the molecular functions,biological processes,and metabolic pathways of differentially expressed proteins.A total of 76 285 peptides and 6 979 quantifiable proteins were identified.A total of 356 proteins showed significant differential expression:153 up-regulated and 203 down-regulated.The protein with the high-est fold change was microtubule motor protein(B4DYE2),and the protein with the lowest fold change was translation initia-tion factor 1(Q6IAV3).GO functional enrichment and KEGG metabolic pathway enrichment analyses indicated that the up-regulated proteins were involved primarily in biological processes and metabolic pathways such as the movement of microtubules and microfilament as well as autophagy,whereas the down-regulated proteins were involved mainly in primary metabolic pathways,such as carbon metabolism,nitrogen metabolism,amino acid biosynthesis,and nucleic acid metabolism,as well as ubiquitin mediated protein hydrolysis.In the process of infection of HTR-8/Svneo by L.monocytogenes,the basal metabolism of host cells may be significantly diminished,and the autophagy level may be high.The significant up-regulation of cell migration-inducing and hyaluronan-binding protein CEMIP(Q8WUJ3)suggested an important role of this protein in regulating the migration and invasion of trophoblast cells,thus causing adverse pregnancy outcomes.Our findings may provide new ideas for the study of the molecular mechanism of L.monocytogenes infection of the placenta.

Objective:To explore the role of NK cells in allogeneic hematopoietic stem cell micro-transplantation(MST)in the treatment of patients with acute myeloid leukemia(AML).Methods:Data from 93 AML patients treated with MST at our center from 2013-2018 were retrospectively analyzed.The induction regimen was anthracycline and cytarabine combined with peripheral blood stem cells transplantation mobilization by granulocyte colony stimulating factor(GPBSC),followed by 2-4 courses of intensive treatment with medium to high doses of cytarabine combined with GPBSC after achieving complete remission(CR).The therapeutic effects of one and two courses of MST induction therapy on 42 patients who did not reach CR before transplantation were evaluated.Cox proportional hazards regression analysis was used to analyze the impact of donor NK cell dose and KIR genotype,including KIR ligand mismatch,2DS1,haplotype,and HLA-Cw ligands on survival prognosis of patients.Results:Forty-two patients received MST induction therapy,and the CR rate was 57.1％after 1 course and 73.7％after 2 courses.Multivariate analysis showed that,medium and high doses of NK cells was significantly associated with improved disease-free survival(DFS)of patients(HR=0.27,P=0.005;HR=0.21,P=0.001),and high doses of NK cells was significantly associated with improved overall survival(OS)of patients(HR=0.15,P=0.000).Donor 2DS1 positive significantly increases OS of patients(HR=0.25,P=0.011).For high-risk patients under 60 years old,patients of the donor-recipient KIR ligand mismatch group had longer DFS compared to the nonmismatch group(P=0.036);donor 2DS1 positive significantly prolonged OS of patients(P=0.009).Conclusion:NK cell dose,KIR ligand mismatch and 2DS1 influence the therapeutic effect of MST,improve the survival of AML patients.

Objective To explore the alterations in gray matter volume(GMV)in adolescents with bipolar disorder(BD).Methods 36 BD patients(BD group)and 37 healthy controls(HC group)who underwent magnetic resonance imaging(MRI)for artificial visual inspection in Affiliated Hangzhou First People's Hospital,School of Medicine,Westlake University from September 2019 to December 2021 were selected.Structural MRI data were processed by using FreeSurferv6.0.0,and statistical analysis were conducted by using SPSS 26.0 and R language software.Receiver operating characteristic(ROC)curve were employed to assess the diagnostic efficacy of various brain regions.Results Compared to HC group,patients in BD group exhibited significant reductions in GMV in the right superior frontal gyrus,right nucleus accumbens,left insula,right lateral orbitofrontal cortex,and right medial orbitofrontal cortex(P＜0.05).ROC curve analysis indicated that area under the curve(AUC)for the right superior frontal gyrus and right nucleus accumbens were 0.739 and 0.712 respectively,while the combined AUC for multiple brain regions was 0.820.Conclusion Adolescents with BD show significant reductions in GMV in specific brain regions,provide reference for the early identification and pathological mechanism research of BD.