BACKGROUND:It has been proved clinically that adhesion of fibrous scar with the dura mater or nerve root after lumbar operation is an important factor for postoperative symptoms,such as postoperative pain and numbness. OBJECTIVE:To verify the inhibitory effect of autologous ligamentum flavum on the formation of epidural fibrous scar after lumbar surgery and explore the possible molecular biological mechanism. METHODS:Forty-eight Japanese white rabbits(6-8 months old)were randomly divided into three groups:a ligamentum flavum preservation group,a ligamentum flavum non-preservation group,and an autologous fat reposition group.A lumbar laminectomy model was established in all the three groups of rabbits,and rabbit epidural tissues were collected at 3 and 6 weeks after modeling.Hematoxylin-eosin staining was used to observe histological changes and the number and density of fibroblasts,VG staining was used to observe the percentage of collagen fiber area,and immunohistochemistry was used to observe the expression of transforming growth factor β1 and Smad3 proteins. RESULTS AND CONCLUSION:Hematoxylin-eosin staining results revealed that fibroblasts in the ligamentum flavum preservation group were few and loosely arranged,while the cells in the ligamentum flavum non-preservation and autologous fat reposition groups were more numerous and closely arranged.The number density of fibroblasts in the ligamentum flavum preservation group was lower than that in the ligamentum flavum non-preservation and autologous fat reposition groups at 3 and 6 weeks after surgery(P＜0.05);however,there was no significant difference between the latter two groups.VG staining results showed that the collagen fibers in the ligamentum flavum preservation group were sparse and distributed unevenly,while a lot of red collagen fibers were gathered in the ligamentum flavum non-preservation and autologous fat reposition groups.The area percentage of collagen fibers in the ligamentum flavum preservation group was lower than that in the ligamentum flavum non-preservation and autologous fat reposition groups at 3 and 6 weeks after surgery(P＜0.05),but there was no significant difference between the latter two groups.The results of immunohistochemistry showed that the degree of positive staining of retained histone the ligamentum flavum preservation group was significantly lower than that of the other two groups.The absorbance value of transforming growth factor β1 and Smad3 in the ligamentum flavum preservation group was significantly lower than that in the other two groups at 3 and 6 weeks after surgery(P＜0.05),but there was no significant difference between the latter two groups.To conclude,there are different degrees of epidural fibrous scar formation after lumbar surgery.If the ligamentum flavum is preserved,it can help to reduce the number of epidural fibroblasts as well as the formation of collagen fibers,thus reducing the adhesion of the fibrous scar tissue to the dural sac and nerve root.The mechanism is not only a purely mechanical blockade,but also to reduce the formation of epidural fibrous scar by interfering with the transforming growth factor β1/Smad3 signaling pathway.

Background Coal workers' pneumoconiosis is a serious occupational disease in China. Exhaled volatile organic compounds (VOCs) can serve as the "breath fingerprint" of internal pathological processes, which provides a theoretical basis for exhaled VOCs to be used as potential non-invasive biomarkers for early diagnosis of coal workers' pneumoconiosis. Objective To screen out the characteristic VOCs and important characteristic VOCs of exhaled air in patients with coal workers' pneumoconiosis, and to explore the potential of these VOCs as biomarkers for early non-invasive diagnosis of the disease. Methods In this study, 27 VOCs in the exhaled breath of 22 patients with stage I coal workers' pneumoconiosis, 77 workers exposed to dust, and 92 healthy controls were quantitatively detected by thermal desorption gas chromatography-mass spectrometry (TD-GC-MS). Substances with P<0.05 in univariate analysis and variable importance projection (VIP) >1 in supervised orthogonal partial least squares discriminant analysis (OPLS-DA) model were selected as the characteristic VOCs for early diagnosis of coal workers' pneumoconiosis. Age was included in the LASSO regression model as a covariate to screen out important characteristic VOCs, and the diagnostic performance was evaluated by receiver operating characteristic (ROC) curve. Spearman correlation was further used to explore the correlation between important characteristic VOCs and clinical lung function indicators. Results Through univariate analysis and OPLS-DA modeling, 8 VOCs were selected, including 2-methylpentane, 3-methylpentane, n-hexane, methylcyclopentane, n-heptane, methylcyclohexane, 4-methyl-2-pentanone, and 2-hexanone, in exhaled breath of patients with coal workers' pneumoconiosis. The concentrations of 4 VOCs, including 3-methylpentane, n-hexane, 4-methyl-2-pentanone, and 2-hexanone, showed a decreasing trend with the increase of dust exposure years. By LASSO regression, the important characteristic VOCs of the coal workers' pneumoconiosis group and the dust exposure group were n-hexane, methylcyclohexane and 4-methyl-2-pentanone, and the important characteristic VOCs of the coal workers' pneumoconiosis group and the healthy group were 2-methyl-pentane and 4-methyl-2-pentanone. The ROC analysis showed that the area under the curve (AUC) of n-hexane, methylcyclohexane, and 4-methyl-2-pentanone were 0.969, 0.909, and 0.956, respectively, and the AUC of combined diagnosis was 0.988 and its Youden index was 0.961, suggesting that these results can serve as a valuable reference for further research on early diagnosis. The Correlation analysis found that there was a positive correlation between n-hexane and lung function indicators in the important characteristic VOCs, indicating that it could indirectly reflect the obstruction of lung function ventilation, further proving that important characteristic VOCs have the potential to monitor lung function decline. Conclusion Three important characteristic VOCs selected in this study have the potential to be used as non-invasive biomarkers for early diagnosis and disease monitoring of coal workers' pneumoconiosis, and are worthy of further study and verification.

OBJECTIVES: Recent evidence suggests that the gut may be a primary site of metformin action. However, studies on the effects of metformin on gut microbiota remain limited, and its impact on gut microbial metabolites such as short-/medium-chain fatty acids is unclear. This study aims to investigate the effects of metformin on gut microbiota, short-/medium-chain fatty acids, and associated metabolic benefits in high-fat diet rats. METHODS: Twenty-four Sprague-Dawley rats were randomly divided into 3 groups: 1) Normal diet group (ND group), fed standard chow; 2) high-fat diet group (HFD group), fed a high-fat diet; 3) high-fat diet + metformin treatment group (HFD+Met group), fed a high-fat diet for 8 weeks, followed by daily intragastric administration of metformin solution (150 mg/kg body weight) starting in week 9. At the end of the experiment, all rats were sacrificed, and serum, liver, and colonic contents were collected for assessment of glucose and lipid metabolism, liver pathology, gut microbiota composition, and the concentrations of short-/medium-chain fatty acids. RESULTS: Metformin significantly improved HFD-induced glucose and lipid metabolic disorders and liver injury. Compared with the HFD group, the HFD+Met group showed reduced abundance of Blautia, Romboutsia, Bilophila, and Bacteroides, while Lactobacillus abundance significantly increased (all P<0.05). Colonic contents of butyric acid, 2-methyl butyric acid, valeric acid, octanoic acid, and lauric acid were significantly elevated (all P<0.05), whereas acetic acid, isoheptanoic acid, and nonanoic acid levels were significantly decreased (all P<0.05). Spearman correlation analysis revealed that Lactobacillus abundance was negatively correlated with body weight gain and insulin resistance, while butyrate and valerate levels were negatively correlated with insulin resistance and liver injury (all P<0.05). CONCLUSIONS Metformin significantly increases the abundance of beneficial bacteria such as Lactobacillus and promotes the production of short-/medium-chain fatty acids including butyric, valeric, and lauric acid in the colonic contents of HFD rats, suggesting that metformin may regulate host metabolism through modulation of the gut microbiota.
Animals ; Metformin/pharmacology* ; Rats, Sprague-Dawley ; Diet, High-Fat/adverse effects* ; Rats ; Gastrointestinal Microbiome/drug effects* ; Male ; Fatty Acids, Volatile/metabolism* ; Fatty Acids/metabolism*

Background and aims:Despite growing evidence linking pretransplant exposure to immune checkpoint inhibitors(ICIs)to increased allograft rejection risk after liver transplantation(LT),a lack of comparative studies to definitively establish the correlation between ICI exposure and adverse short-term outcomes after LT exists.This study aimed to analyze the impact of preoperative ICI exposure on short-term post-LT prognosis and allograft rejection risk.Methods:This retrospective cohort study included 121 recipients who underwent LT for hepatocellular carcinoma(HCC)between June 2019 and March 2023.The recipients were categorized into ICI(n=35)and non-ICI(n=86)exposure groups based on pretransplant ICI exposure.Demographics,clinical characteristics,and short-term outcomes were compared between the cohorts.Kaplan-Meier analysis evaluated the impact of ICI exposure on graft survival.Univariate and multivariate logistic regression models assessed the impact of patient characteristics on allograft rejection.Results:Recipients with or without ICI exposure exhibited comparable demographic baseline charac-teristics.The incidences of early allograft dysfunction and biliary and vascular complications were similar between both groups.Post-transplant infection incidence was 37.1％and 20.9％in the ICI and non-ICI groups,respectively(P=0.064).Allograft rejection rates were significantly higher in the ICI group than in the non-ICI group(22.9％vs.5.8％,P=0.015).The ICI group exhibited a higher 90-day post-transplant mortality rate than that of the non-ICI group(14.3％vs.2.3％,P=0.034).Logistic regression analyses demonstrated that allograft rejection independently correlated with 90-day post-transplant mortality,with ICI exposure being an independent risk factor for allograft rejection.In recipients with ICI exposure,a shorter interval between ICIs and LT(washout period)was significantly associated with a higher allograft rejection risk,with the optimal washout period identified as 21 days for predicting 90-day rejection-free survival(P=0.0001).Moreover,in recipients with allograft rejection,the peripheral CD4+/CD8+T cell ratio was much lower in the ICI group than in the non-ICI group.Conclusions:Pretransplant ICI exposure was an independent risk factor for allograft rejection and was significantly associated with 90-day post-transplant mortality after LT for HCC.A ≤21-day washout period was significantly associated with allograft rejection.Future multicenter studies with larger cohorts and prospective designs are essential to validate these findings,confirm causality,and establish standardized clinical guidelines for ICI use before transplantation.Trail registration:ClinicalTrials.gov NCT05913583.

The composition and concentration of volatile organic compounds (VOCs) in exhaled breath are closely related to human health and the analysis of VOCs by collecting human exhaled breath has been widely used in disease surveillance research. This article reviewed the collection, enrichment, and detection methods of exhaled VOCs, which can provide a reference for selecting appropriate technology for follow-up research. The exhaled breath collection devices mainly include sampling bags for mixed exhaled breath and biological volatile organic compound (Bio-VOC) samplers for alveolar air. The pre-enrichment equipment included thermal desorption (TD), solid-phase microextraction device (SPME), and needle trap device (NTD). The detection methods of exhaled VOCs include gas chromatography-mass spectrometry (GC-MS), proton transfer reaction mass spectrometry (PTR-MS), selective ion flow tube mass spectrometry (SIFT-MS), and electronic nose. At present, the collection and enrichment technology of exhaled breath is not mature yet, and its influence on the results of detection is lack of evaluation. In the future, the research on collection and enrichment technology of exhaled breath should be strengthened to further promote the application of exhaled breath in disease surveillance research.

Occupational pneumoconiosis (referred to as “pneumoconiosis”) caused by exposure to occupational dust is the most serious occupational disease in China. Biological monitoring on occupational populations exposed to dust is important for the prevention, diagnosis, and treatment of pneumoconiosis. Biological monitoring is a systematic engineering process that includes a series of processes such as biological samples selection, selection of biological monitoring indicators, and selection of detection methods. The biological samples for biological monitoring mainly include urine, blood, exhaled breath gas, bronchoalveolar lavage fluid, saliva, sputum, and more. The indicators of biological monitoring involve multiple pathways such as oxidative stress, inflammatory response, collagen synthesis/degradation, phagocytic cell apoptosis, and pathways related to the formation of pneumoconiosis. Suitable detection methods need to be determined upon different biological monitoring indicators, including enzyme-linked immunosorbent assay, high-performance liquid chromatography, high-performance liquid chromatography-tandem mass spectrometry, inductively coupled plasma mass spectrometry, etc. Currently, there is a lack of true clinically valuable biological monitoring indicators that can indicate the correlation between dust exposure and the hazards of occupational populations, and there are no systematic and complete biological monitoring methods reported. It is necessary to further standardize the biological monitoring process and search for specific biological monitoring indicators.

Background Per- and polyfluoroalkyl substances (PFAS) are a class of persistent organic pollutants that possess potential toxicity to the human body. The production and utilization of diverse emerging PFAS have resulted in widespread human exposure. Therefore, it is imperative to establish a quantitative methodology encompassing a wide range of PFAS for a comprehensive assessment of human exposure to these compounds. Objective To establish a high-throughput quantitative method for the simultaneous determination of 53 PFAS in human serum based on ultra-high-performance liquid chromatography-Q Exactive high resolution mass spectrometry (UPLC-Q Exactive HRMS). Methods The extraction recoveries of hydrophilic-lipophilic balance (HLB) column, weak anionexchange (WAX) column, and 96-well WAX μElution plate were compared to select the SPE column with the highest recovery. The retention time and peak shape of the target compounds were compared between ACQUITY UPLC BEH C₁₈ column and Accucore aQ column, and the more cost-effective column was chosen. The effects of adding different levels of ammonium formate (0, 2, 5 and 10 mmol·L⁻¹) in mobile phase on peak shape and target response were compared to determine the optimal buffer salt concentration. The optimal spray voltage was obtained by comparing −2 kV and −4 kV. The proposed method was validated from the aspects of selectivity, standard curve, limits of detection, precision, accuracy, and matrix effect. The method was applied to 142 umbilical serum samples. Results The best recovery rate (64%-118%) was achieved by using 96-well WAX μElution plate. The optimal separation and peak shape were obtained by utilizing Accucore aQ column with H₂O-methanol (containing 5 mmol·L⁻¹ ammonium formate) as the mobile phase. Less in-source collision and better target response were observed when the spray voltage was set to −2 kV. All target analytes had a good linearity, with R² > 0.99. The limits of detection ranged from 0.01 to 0.50 μg·L⁻¹, and the recovery ranged from 69% to 127% with the precision less than 26%. A total of 31 PFAS were detected in the 142 actual samples, among which 14 PFAS had a detection frequency over 50%. Perfluorooctanoic acid showed the highest median concentration of 4.16 μg·L⁻¹, followed by 6:2 chlorinated polyfluorinated ether sulfonate and perfluorooctane sulfonates (3.50 μg·L⁻¹ and 1.59 μg·L⁻¹, respectively). Conclusion In this study, we establish a UPLC-Q Excative HRMS method for simutanious determination of 53 PFAS concentrations in serum. This method has the advantages of wide coverage of PFAS, good selectivity, and easy operation, and is suitable for biological detection with a large sample size.