Macrophage MKL1 contributes to cardiac fibrosis in a mouse model of myocardial infarction.

AIMS: Cardiac fibrosis is characterized by aberrant collagen deposition in the heart. Macrophage polarization or infiltration is the main reason to accelerate the collagen deposition. We attempted to investigate the involvement of MKL1 in macrophages during the development of cardiac fibrosis. MATERIALS AND METHODS: Cardiac fibrosis is induced by myocardial infarction (MI). The MKL1f/f mice were crossed to the Lyz2-cre mice to generate macrophage conditional MKL1 knockout mice (MKL1ΔMφ). In addition, macrophage conditional MKL1 overexpression mice (MKL1Mϕ-OE) were constructed by crossing Lyz2-cre mice to MKL1ΔN200-Rosa26 mice. KEY FINDINGS: MKL1 expression was significantly increased in macrophages of both ischemic cardiomyopathy (ICM) patients and mice induced to develop myocardial infarction. Deletion of MKL1 in macrophages improved the heart function after MI-induced cardiac fibrosis. Consistently, MKL1Mϕ-OE mice displayed more severe cardiac fibrosis and worsened heart function than the control mice after MI. Moreover, administration of a small-molecule MKL1 inhibitor CCG-1423 also decreased the collagen deposition after MI. SIGNIFICANCE: Our data demonstrate that MKL1 in macrophages contributes to cardiac fibrosis pathogenesis and reinforce the notion that targeting MKL1 may yield effective antifibrotic therapeutics in the heart.

Iron metabolism indexes as predictors of the incidence of cardiac surgery-associated acute kidney surgery.

BACKGROUND: Acute kidney injury (AKI) is a major complication following cardiac surgery. We explored the clinical utility of iron metabolism indexes for identification of patients at risk for AKI after cardiac surgery. METHODS: This prospective observational study included patients who underwent cardiac surgery between March 2023 and June 2023. Iron metabolism indexes were measured upon admission to the intensive care unit. Multivariable logistic regression analyses were performed to explore the relationship between iron metabolism indexes and cardiac surgery-associated AKI (CSA-AKI). Receiver operating characteristic (ROC) curve was used to assess the predictive ability of iron, APACHE II score and the combination of the two indicators. Restricted cubic splines (RCS) was used to further confirm the linear relationship between iron and CSA-AKI. RESULTS: Among the 112 recruited patients, 38 (33.9%) were diagnosed with AKI. Multivariable logistic regression analysis indicated that APACHE II score (odds ratio [OR], 1.208; 95% confidence interval [CI], 1.003-1.455, P = 0.036) and iron (OR 1.069; 95% CI 1.009-1.133, P = 0.036) could be used as independent risk factors to predict CSA-AKI. ROC curve analysis showed that iron (area under curve [AUC] = 0.669, 95% CI 0.572-0.757), APACHE II score (AUC = 0.655, 95% CI 0.557-0.744) and iron and APACHE II score combination (AUC = 0.726, 95% CI 0.632-0.807) were predictive indicators for CSA-AKI. RCS further confirmed the linear relationship between iron and CSA-AKI. CONCLUSIONS: Elevated iron levels were independently associated with higher risk of CSA-AKI, and there was a linear relationship between iron and CSA-AKI.

[Inhibition of type 3 deiodinase expression can improve mitochondrial function in skeletal muscle of sepsis by up-regulating peroxisome proliferator-activated receptor-γ coactivator-1α].

OBJECTIVE: To investigate the protective effects and mechanisms of targeted inhibition of type 3 deiodinase (Dio3) on skeletal muscle mitochondria in sepsis. METHODS: (1) In vivo experiments: adeno-associated virus (AAV) was employed to specifically target Dio3 expression in the anterior tibial muscle of rats, and a septic rat model was generated using cecal ligation and puncture (CLP). The male Sprague-Dawley (SD) rats were divided into shNC+Sham group, shD3+Sham group, shNC+CLP group, and shD3+CLP group by random number table method, with 8 rats in each group. After CLP modeling, tibial samples were collected and Western blotting analysis was conducted to assess the protein levels of Dio3, peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α), and silence-regulatory protein 1 (SIRT1). Real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) was utilized to examine mRNA expression of genes including thyroid hormone receptors (THRα, THRß), monocarboxylate transporter 10 (MCT10), mitochondrial DNA (mtDNA), and PGC1α. Transmission electron microscopy was employed to investigate mitochondrial morphology. (2) In vitro experiments: involved culturing C2C12 myoblasts, interfering with Dio3 expression using lentivirus, and constructing an endotoxin cell model by treating cells with lipopolysaccharide (LPS). C2C12 cells were divided into shNC group, shD3 group, shNC+LPS group, and shD3+LPS group. Immunofluorescence colocalization analysis was performed to determine the intracellular distribution of PGC1α. Co-immunoprecipitation assay coupled with Western blotting was carried out to evaluate the acetylation level of PGC1α. RESULTS: (1) In vivo experiments: compared with the shNC+Sham group, the expression of Dio3 protein in skeletal muscle of the shNC+CLP group was significantly increased (Dio3/ß-Tubulin: 3.32±0.70 vs. 1.00±0.49, P < 0.05), however, there was no significant difference in the shD3+Sham group. Dio3 expression in the shD3+CLP group was markedly reduced relative to the shNC+CLP group (Dio3/ß-Tubulin: 1.42±0.54 vs. 3.32±0.70, P < 0.05). Compared with the shNC+CLP group, the expression of T3-regulated genes in the shD3+CLP group were restored [THRα mRNA (2-ΔΔCt): 0.67±0.05 vs. 0.33±0.01, THRß mRNA (2-ΔΔCt): 0.94±0.05 vs. 0.67±0.02, MCT10 mRNA (2-ΔΔCt): 0.65±0.03 vs. 0.57±0.02, all P < 0.05]. Morphology analysis by electron microscopy suggested prominent mitochondrial damage in the skeletal muscle of the shNC+CLP group, while the shD3+CLP group exhibited a marked improvement. Compared with the shNC+Sham group, the shNC+CLP group significantly reduced the number of mitochondria (cells/HP: 10.375±1.375 vs. 13.750±2.063, P < 0.05), while the shD3+CLP group significantly increased the number of mitochondria compared to the shNC+CLP group (cells/HP: 11.250±2.063 vs. 10.375±1.375, P < 0.05). The expression of mtDNA in shNC+CLP group was markedly reduced compared with shNC+Sham group (copies: 0.842±0.035 vs. 1.002±0.064, P < 0.05). Although no difference was detected in the mtDNA expression between shD3+CLP group and shNC+CLP group, but significant increase was found when compared with the shD3+Sham group (copies: 0.758±0.035 vs. 0.474±0.050, P < 0.05). In the shD3+CLP group, PGC1α expression was significantly improved at both transcriptional and protein levels relative to the shNC+CLP group [PGC1α mRNA (2-ΔΔCt): 1.49±0.13 vs. 0.68±0.06, PGC1α/ß-Tubulin: 0.76±0.02 vs. 0.62±0.04, both P < 0.05]. (2) In vitro experiments: post-24-hour LPS treatment of C2C12 cells, the cellular localization of PGC1α became diffuse; interference with Dio3 expression promoted PGC1α translocation to the perinuclear region and nucleus. Moreover, the acetylated PGC1α level in the shD3+LPS group was significantly lower than that in the shNC+LPS group (acetylated PGC1α/ß-Tubulin: 0.59±0.01 vs. 1.24±0.01, P < 0.05), while the expression of the deacetylating agent SIRT1 was substantially elevated following Dio3 inhibition (SIRT1/ß-Tubulin: 1.04±0.04 vs. 0.58±0.03, P < 0.05). When SIRT1 activity was inhibited by using EX527, PGC1α protein expression was notably decreased compared to the shD3+LPS group (PGC1α/ß-Tubulin: 0.92±0.03 vs. 1.58±0.03, P < 0.05). CONCLUSIONS: Inhibition of Dio3 in skeletal muscle reduced the acetylation of PGC1α through activating SIRT1, facilitating nuclear translocation of PGC1α, thereby offering protection against sepsis-induced skeletal muscle mitochondrial damage.

Corn Oligopeptide Alleviates Nonalcoholic Fatty Liver Disease by Regulating the Sirtuin Signaling Pathway.

Nonalcoholic fatty liver disease (NAFLD) represents the most prevalent type of chronic liver disease, spanning from simple steatosis to nonalcoholic steatohepatitis (NASH). Corn oligopeptide (CP) is a functional peptide known for its diverse pharmacological effects on metabolism. In this study, we evaluated the protective activity of CP against fatty liver disease. Oral administration of CP significantly reduced body weight gain by 2.95%, serum cholesterol by 22.54%, and liver injury, as evidenced by a reduction of 32.19% in serum aspartate aminotransferase (AST) and 49.10% in alanine aminotransferase (ALT) levels in mice subjected to a high-fat diet (HFD). In a streptozotocin/HFD-induced NASH mouse model, CP attenuated body weight gain by 5.11%, liver injury (with a 34.15% decrease in AST and 11.43% decrease in ALT), and, to some extent, liver inflammation and fibrosis. Proteomic analysis revealed the modulation of oxidative phosphorylation and sirtuin (SIRT) signaling pathways by CP. Remarkably, CP selectively inhibited the hepatic expression of mitochondrial SIRT3 and SIRT5 in both HFD and NASH models. In summary, CP demonstrates a preventive effect against metabolic-stress-induced NAFLD progression by modulating oxidative stress and the SIRT signaling pathway, suggesting the potential of CP as a therapeutic agent for the treatment of NAFLD and advanced-stage NASH.

[Predictive value of lipoproteins on progression to chronic critical illness in intensive care unit patients].

OBJECTIVE: To explore the predictive value of lipoproteins on the progression of critically ill patients to chronic critical illness (CCI). METHODS: A retrospective cohort study was conducted to analyze clinical data of patients admitted to the intensive care unit (ICU) of Nanjing Drum Tower Hospital from January 1, 2020, to December 31, 2022. The levels of high-density lipoprotein (HDL), low-density lipoprotein (LDL) and apolipoproteins (ApoA-I, ApoB) at 1, 3, 7, 14 and 21 days after admission to ICU were collected. The progression to CCI was recorded. CCI was defined as the length of ICU stay ≥14 days with sustained organ dysfunction [sequential organ failure assessment (SOFA) score ≥2]. Differences in lipoprotein levels between the patients with and without CCI were compared. Multivariate Logistic regression was used to analyze risk factors for critically ill patients progressing to CCI. Receiver operator characteristic curve (ROC curve) was drawn to evaluate the predictive value of lipoproteins on critically ill patients progressing to CCI. RESULTS: A total of 200 patients were enrolled in the final analysis. 137 patients (68.5%) progressed to CCI, and 63 patients (31.5%) did not. The lipoprotein indicators in the CCI group showed a decrease after the acute phase, while the lipoprotein indicators in the non-CCI group showed an increase. The levels of HDL, LDL, ApoA-I, and ApoB at various time points in the CCI group were significantly lower than those in the non-CCI group. HDL at 7 days in the CCI group was significantly lower than that in the non-CCI group [mmol/L: 0.44 (0.31, 0.61) vs. 0.67 (0.49, 0.75), P < 0.01]. Multivariate Logistic regression analysis showed that 7-day HDL was an independent risk factor for critically ill patients progressing to CCI [odds ratio (OR) = 0.033, 95% confidence interval (95%CI) was 0.004-0.282, P = 0.002]. ROC curve analysis showed that the area under the ROC curve (AUC) of 7-day HDL for predicting critically ill patients progressing to CCI was 0.702, with a 95%CI of 0.625-0.779, P < 0.001. When the optimal cut-off value was 0.59 mmol/L, the sensitivity was 69.8%, and the specificity was 72.4%. CONCLUSIONS: The low level of lipoproteins is closely related to the progression of critically ill patients, and 7-day HDL has a certain predictive value for critically ill patients progressing to CCI. Continuously observation of the change trend of lipoprotein level is helpful to judge the progression of CCI in critically ill patients.

Optic Nerve Sheath Diameter Sonography for the Diagnosis of Intracranial Hypertension in Traumatic Brain Injury: A Systematic Review and Meta-Analysis.

OBJECTIVES: Timely diagnosis and management of elevated intracranial pressure (ICP) in patients with traumatic brain injury (TBI) can significantly reduce mortality rates. Ultrasound examination of the optic nerve sheath diameter (ONSD) is considered a potential, noninvasive, and effective method for assessing ICP. We conducted a systematic review and meta-analysis of ONSD ultrasound detection and invasive ICP monitoring methods to compare and evaluate the diagnostic accuracy of ONSD ultrasound detection methods for intracranial hypertension (IH) in patients with TBI. METHODS: We searched the Web of Science, PubMed, and Embase databases to assess the diagnostic accuracy of ONSD sonography for predicting increased ICP. The 2 authors independently extracted the collected data. Simultaneously, the QUADAS-2 tool was used to evaluate the bias risk of each study and conducted random-effects meta-analyses for the accuracy and specificity of diagnosis, and calculated pooled estimates. RESULTS: Ten studies with 512 patients were included. The diagnostic accuracy of ONSD sonography for IH was revealed as a pooled sensitivity of 0.85 (95% confidence interval [CI], 0.79-0.89) and specificity of 0.88 (95% CI, 0.80-0.93), compared with the invasive ICP monitoring standard for patients with TBI. CONCLUSIONS: ONSD sonography may be a useful method for predicting increased ICP in adult patients with TBI. Further clinical studies are required to confirm the diagnostic value of ONSD sonography.

[Experimental study on high-frequency subharmonic scattering characteristics of ultrasound contrast agent microbubbles under low ambient pressure].

Correlation between nonlinear subharmonic scattering of ultrasound contrast agent microbubbles and ambient pressure is expected to be used for local brain tissue pressure monitoring. Although high-frequency ultrasound has achieved high-resolution imaging of intracranial microvessels, the research on high-frequency subharmonic scattering characteristics of microbubbles is insufficient at present, which restricts the research progress of estimating local brain tissue pressure based on high-frequency subharmonic scattering of microbubbles. Therefore, under the excitation of 10 MHz high-frequency ultrasound, the effects of different acoustic pressures and ambient pressures on the high-frequency subharmonic scattering characteristics of three different ultrasound contrast agents including SonoVue, Sonazoid and Huashengxian were investigated in this in vitro study. Results showed that the subharmonic scattering amplitudes of the three microbubbles increased with the increase of ambient pressure at the peak negative acoustic pressures of 696, 766 and 817 kPa, and there was a favorable linear correlation between subharmonic amplitude and ambient pressure. Under the above three acoustic pressures, the highest correlation coefficient of SonoVue was 0.948 ( P = 0.03), the highest sensitivity of pressure measurement was 0.248 dB/mm Hg and the minimum root mean square error (RMSE) was 2.64 mm Hg. Sonazoid's highest correlation coefficient was 0.982 ( P < 0.01), the highest sensitivity of pressure measurement was 0.052 dB/mm Hg and the minimum RMSE was 1.51 mm Hg. The highest correlation coefficient of Huashengxian was 0.969 ( P = 0.02), the highest sensitivity of pressure measurement was 0.098 dB/mm Hg and the minimum RMSE was 2.00 mm Hg. The above in vitro experimental results indicate that by selecting ultrasound contrast agent microbubbles and optimizing acoustic pressure, the correlation between high-frequency subharmonic scattering of microbubbles and ambient pressure can be improved, the sensitivity of pressure measurement can be upgraded, and the measurement error can be reduced to meet the clinical demand for local brain tissue pressure measurement, which provided an important experimental basis for subsequent research in vivo.

Acute muscle wasting rate assessment and long-term mortality in critically ill trauma.

BACKGROUND AND OBJECTIVES: To evaluate the relationship between acute muscle wasting rate and long-term mortality in critically ill trauma. METHODS AND STUDY DESIGN: A single-center, retrospective study was conducted in critically ill trauma. Patients with Computed Tomography scans including the L3 vertebra within 24 hours and at 1 week after trauma were recruited. Acute muscle wasting rate was defined as the mean percent variation per day of skeletal muscle index in the first week after trauma. Multivariate logistic regression analysis and receiver operating characteristic curve analysis were performed to determine whether acute muscle wasting rate could help predict hospital malnutrition and 1-year mortality. RESULTS: Skeletal muscle index was 49.3±10.7 cm2/m2 at baseline and decreased to 45.1±9.6 cm2/m2 (p<0.001) at 1 week and 39.8±10.8cm2/m2 (p<0.001) at 1 month after trauma. A sustained decrease of skeletal muscle index was observed from baseline up to 6 months (33.7±8.4cm2/m2, p<0.001) post trauma, and lasted for 1 year (37.7±5.6cm2/m2, p=0.004). Logistic regression analysis showed that acute muscle wasting rate was an independent risk factor for hospital malnutrition and 1-year mortality. Every 1% absolute increase of acute muscle wasting rate was associated with 1.82-fold higher odds of 1-year mortality in critically ill trauma. The area under curve of acute muscle wasting rate was 0.813 for hospital malnutrition prediction and 0.715 for 1-year mortality prediction. CONCLUSIONS: Acute muscle wasting rate was independently associated with higher 1-year mortality and hospital malnutrition in critically ill trauma.

Corrigendum: Acute gastrointestinal injury and altered gut microbiota are related to sepsis-induced cholestasis in patients with intra-abdominal infection: a retrospective and prospective observational study.

[This corrects the article DOI: 10.3389/fmed.2023.1144786.].

Acute gastrointestinal injury and altered gut microbiota are related to sepsis-induced cholestasis in patients with intra-abdominal infection: a retrospective and prospective observational study.

Background: Sepsis-associated liver dysfunction (SALD) has high incidence and mortality in patients with intra-abdominal infection (IAI). The associations between acute gastrointestinal injury (AGI), gut microbiota, and SALD were evaluated in patients with IAI. Methods: A retrospective study was conducted to assess the relationship between AGI and SALD in patients with IAI. Patients were divided into non-SALD and sepsis-induced cholestasis (SIC) groups, which is a subtype of SALD. SIC was defined as total bilirubin >2 mg/dL. AGI incidences between the two groups were compared using Chi-square test. Subsequently, a prospective study was conducted to investigate the gut microbiota differences between patients without SALD and those with SIC. Fecal samples were collected on days 1, 3, and 7 after admission to analyze changes in gut microbiota using 16S ribosomal ribonucleic acid sequencing. Results: One hundred thirty-four patients with IAI were included retrospectively, with 77 SALD and 57 non-SALD cases. Among patients with SALD, 71 were diagnosed with SIC. Patients with SIC had a higher incidence of AGI compared to those without SALD (28.07% vs. 56.34%, p < 0.05), and a severity-dependent relationship was found between AGI grade and SIC occurrence. Subsequently, 20 patients with IAI were recruited prospectively, with 10 patients each assigned to the non-SALD and SIC groups. Patients with SIC had a more severe gut microbiota disorder on day 7 than those without SALD, including lower microbiota diversities, decreased abundance of Firmicutes and Bacteroidetes, and increased abundance of Proteobacteria and Actinobacteria at the phylum level. Furthermore, Burkholderia - Caballeronia - Paraburkholderia and Delftia, the two most abundant genera, were significantly higher in the SIC group than in the non-SALD group. Functional prediction analysis showed that the top three KEGG pathways were ribosome, pyrimidine metabolism, and the two-component system. During the first week, the abundance of Proteobacteria decreased significantly, whereas Cyanobacteria increased in the non-SALD group; however, the phyla taxa did not change significantly in the SIC group. Conclusion: There exists a severity-dependent relationship between AGI grade and SIC occurrence in adult patients with IAI. A severe gut microbiota disorder was discovered in SIC during the first week of the intensive care unit stay.

Association of longitudinal changes in skeletal muscle mass with prognosis and nutritional intake in acutely hospitalized patients with abdominal trauma: a retrospective observational study.

Background: The objective of this study was to explore whether longitudinal changes in skeletal muscle mass, from hospital admission to 3 weeks post-trauma, are associated with poor prognosis and nutritional intake in acutely hospitalized patients with abdominal trauma. Methods: A single-center retrospective observational review was conducted on 103 patients with abdominal trauma admitted to the Affiliated Jinling Hospital, Medical School of Nanjing University between January 2010 and April 2020. Skeletal muscle mass was assessed by abdominal computed tomography (CT) performed within 14 days before surgery and on post-trauma days 1-3 (week 0), 7-10 (week 1), 14-17 (week 2), and 21-24 (week 3). The skeletal muscle index (SMI) at L3, change in SMI per day (ΔSMI/day), and percent change in SMI per day (ΔSMI/day [%]) were calculated. The receiver-operating characteristic (ROC) curve was used to evaluate the discriminatory performance of ΔSMI/day (%) for mortality. Linear correlation analysis was used to evaluate the associations between ΔSMI/day (%) and daily caloric or protein intake. Results: Among the included patients, there were 91 males and 12 females (mean age ± standard deviation 43.74 ± 15.53 years). ΔSMI4-1/d (%) had a ROC-area under the curve of 0.747 (p = 0.048) and a cut-off value of -0.032 for overall mortality. There were significant positive correlations between ΔSMI4-1/d (%) and daily caloric intake and protein intake (Y = 0.0007501*X - 1.397, R2 = 0.282, R = 0.531, p < 0.001; Y = 0.008183*X - 0.9228, R2 = 0.194, R = 0.440, p < 0.001). Δ SMI/day (%) was positively correlated with daily caloric intake ≥80% of resting energy expenditure in weeks 2, 3, and 1-3 post-trauma and with protein intake >1.2 g/kg/d in weeks 3 and 1-3 post-trauma. Conclusion: Loss of skeletal muscle mass is associated with poor prognosis and nutritional intake in patients admitted to hospital with abdominal trauma.

Targeting transglutaminase 2 mediated exostosin glycosyltransferase 1 signaling in liver cancer stem cells with acyclic retinoid.

Transglutaminase 2 (TG2) is a multifunctional protein that promotes or suppresses tumorigenesis, depending on intracellular location and conformational structure. Acyclic retinoid (ACR) is an orally administered vitamin A derivative that prevents hepatocellular carcinoma (HCC) recurrence by targeting liver cancer stem cells (CSCs). In this study, we examined the subcellular location-dependent effects of ACR on TG2 activity at a structural level and characterized the functional role of TG2 and its downstream molecular mechanism in the selective depletion of liver CSCs. A binding assay with high-performance magnetic nanobeads and structural dynamic analysis with native gel electrophoresis and size-exclusion chromatography-coupled multi-angle light scattering or small-angle X-ray scattering showed that ACR binds directly to TG2, induces oligomer formation of TG2, and inhibits the transamidase activity of cytoplasmic TG2 in HCC cells. The loss-of-function of TG2 suppressed the expression of stemness-related genes, spheroid proliferation and selectively induced cell death in an EpCAM+ liver CSC subpopulation in HCC cells. Proteome analysis revealed that TG2 inhibition suppressed the gene and protein expression of exostosin glycosyltransferase 1 (EXT1) and heparan sulfate biosynthesis in HCC cells. In contrast, high levels of ACR increased intracellular Ca2+ concentrations along with an increase in apoptotic cells, which probably contributed to the enhanced transamidase activity of nuclear TG2. This study demonstrates that ACR could act as a novel TG2 inhibitor; TG2-mediated EXT1 signaling is a promising therapeutic target in the prevention of HCC by disrupting liver CSCs.

Rapid Identification of Pathogens in Severe Pneumonia by Species-specific Bacterial Detector (SSBD).

Fast and accurate detection of pathogenic bacterial infection in patients with severe pneumonia is significant to its treatment. The traditional culture method currently used by most medical institutions relies on a time-consuming culture process (over two days) that is unable to meet clinical needs. Rapid, accurate, and convenient species-specific bacterial detector (SSBD) has been developed to provide timely information on pathogenic bacteria. The SSBD was designed based on the fact that Cas12a indiscriminately cleaves any DNA following the binding of the crRNA-Cas12a complex to the target DNA molecule. SSBD involves two processes, starting with PCR of the target DNA using primers specific for the pathogen, followed by detection of the existence of pathogen target DNA in the PCR product using the corresponding crRNA and Cas12a protein. Compared to the culture test, the SSBD can obtain accurate pathogenic information in only a few hours, dramatically shortening the detection time and allowing more patients to benefit from timely clinical treatment.

Biochemical characterization of RNase R 2'-O-methylation sensitivity.

RNase R is a member of the RNA exonuclease family that digests RNA in the 3'-5' direction. Previous studies have identified RNase R from Mycoplasma genitalium (MgR) as the only RNA exonuclease that is sensitive to 2'-O-methylation (Nm) modification. However, the mechanism underlying this characteristic is not well understood. In this study, we aimed to explore the molecular mechanism of RNase R Nm sensitivity using an improved assay that can better evaluate Nm sensitivity. By comparing the sequences of five wild-type RNase R variants from Mycoplasma, we identified the importance of loop 18 in Nm sensitivity. Furthermore, we demonstrated the critical roles of L283, T278, and T279 within loop18. Our findings deepen the understanding of the molecular mechanism of why MgR is sensitive to Nm and provide a potential direction of protein engineering for applications.

Real-Time Prediction of Sepsis in Critical Trauma Patients: Machine Learning-Based Modeling Study.

BACKGROUND: Sepsis is a leading cause of death in patients with trauma, and the risk of mortality increases significantly for each hour of delay in treatment. A hypermetabolic baseline and explosive inflammatory immune response mask clinical signs and symptoms of sepsis in trauma patients, making early diagnosis of sepsis more challenging. Machine learning-based predictive modeling has shown great promise in evaluating and predicting sepsis risk in the general intensive care unit (ICU) setting, but there has been no sepsis prediction model specifically developed for trauma patients so far. OBJECTIVE: To develop a machine learning model to predict the risk of sepsis at an hourly scale among ICU-admitted trauma patients. METHODS: We extracted data from adult trauma patients admitted to the ICU at Beth Israel Deaconess Medical Center between 2008 and 2019. A total of 42 raw variables were collected, including demographics, vital signs, arterial blood gas, and laboratory tests. We further derived a total of 485 features, including measurement pattern features, scoring features, and time-series variables, from the raw variables by feature engineering. The data set was randomly split into 70% for model development with stratified 5-fold cross-validation, 15% for calibration, and 15% for testing. An Extreme Gradient Boosting (XGBoost) model was developed to predict the hourly risk of sepsis at prediction windows of 4, 6, 8, 12, and 24 hours. We evaluated model performance for discrimination and calibration both at time-step and outcome levels. Clinical applicability of the model was evaluated with varying levels of precision, and the potential clinical net benefit was assessed with decision curve analysis (DCA). A Shapley additive explanation algorithm was applied to show the effect of features on the prediction model. In addition, we trained an L2-regularized logistic regression model to compare its performance with XGBoost. RESULTS: We included 4603 trauma patients in the study, 1196 (26%) of whom developed sepsis. The XGBoost model achieved an area under the receiver operating characteristics curve (AUROC) ranging from 0.83 to 0.88 at the 4-to-24-hour prediction window in the test set. With a ratio of 9 false alerts for every true alert, it predicted 73% (386/529) of sepsis-positive timesteps and 91% (163/179) of sepsis events in the subsequent 6 hours. The DCA showed our model had a positive net benefit in the threshold probability range of 0 to 0.6. In comparison, the logistic regression model achieved lower performance, with AUROC ranging from 0.76 to 0.84 at the 4-to-24-hour prediction window. CONCLUSIONS: The machine learning-based model had good discrimination and calibration performance for sepsis prediction in critical trauma patients. Using the model in clinical practice might help to identify patients at risk of sepsis in a time window that enables personalized intervention and early treatment.

Subcutaneous Adipose Tissue Is Associated with Acute Kidney Injury after Abdominal Trauma Based on the Generalized Propensity Score Approach: A Retrospective Cohort Study.

INTRODUCTION: Obesity is associated with an increased risk of acute kidney injury (AKI) after trauma. However, the associations between different adipose tissue depots and AKI remain unknown. Our study aimed to quantify the effect of abdominal adiposity on AKI in trauma patients. METHODS: We performed a retrospective cohort study of abdominal trauma patients who were admitted to our hospital from January 2010 to March 2020. Abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were measured at the level of the third lumbar vertebra using computed tomography. Causal modeling based on the generalized propensity score was used to quantify the effects of body mass index (BMI), VAT, and SAT on AKI. RESULTS: Among 324 abdominal trauma patients, 67 (20.68%) patients developed AKI. Patients with AKI had higher BMI (22.46 kg/m2 vs. 22.04 kg/m2, p = 0.014), higher SAT areas (89.06 cm2 vs. 83.39 cm2, p = 0.151), and higher VAT areas (140.02 cm2 vs. 91.48 cm2, p = 0.001) than those without AKI. By using causal modeling, we found that the risk of developing AKI increased by 8.3% (p = 0.001) and 4.8% (p = 0.022) with one unit increase in BMI (per 1 kg/m2) and ten units increase in SAT (per 10 cm2), respectively. However, VAT did not show a significant association with AKI (p = 0.327). CONCLUSION: SAT, but not VAT, increased the risk of AKI among abdominal trauma patients. Measurement of SAT might help identify patients at higher risk of AKI.

A novel mini-invasive step-up approach for the treatment of severe acute pancreatitis with extensive infected necrosis: A single center case series study.

RATIONALE: Complete removal of necrosis is critical for treating patients with severe acute pancreatitis (SAP) presenting infection of pancreatic necrosis (IPN). Frequently used mini-invasive methods include the surgical step-up approach suitable for necrosis extending laterally, whereas the endoscopic step-up approach is suitable for medial necrosis. However, in patients with extensive IPN, either approach alone usually has limited treatment effects. PATIENT CONCERNS: We describe a case series of combined mini-invasive step-up approach for treating extensive IPN. DIAGNOSES: Patients were diagnosed with SAP and had extensive IPN. INTERVENTIONS: Seven patients with SAP and extensive IPN were enrolled. All patients underwent a combined step-up approach comprising 4 steps: percutaneous catheter drainage, continuous negative pressure irrigation (CNPI), percutaneous endoscopic necrosectomy (PEN), and transgastric necrosectomy (TN). OUTCOMES: The median interval from symptom onset to percutaneous catheter drainage and CNPI was 11 days (range, 6-14) and 18 days (range, 14-26), and the median CNPI duration was 84 days (range, 54-116). The median interval from the onset of symptoms to PEN and TN was 36 days (range, 23-42) and 41 days (range, 34-48), respectively, and the median number of procedures was 2 (range, 1-2) for PEN and 3 (range, 2-4) for TN. Only a minor case of abdominal bleeding and a pancreatic-cutaneous fistula were reported, both resolved after conservative treatment. The median length of stay in the intensive care unit was 111 days (range, 73-133); all patients survived. LESSONS: This mini-invasive step-up approach shows promising clinical effects and is relatively safe in critically ill patients with extensive IPN and high-risk surgical intervention.

High Fat-to-Muscle Ratio Was Associated with Increased Clinical Severity in Patients with Abdominal Trauma.

Overweight and moderate obesity confer a survival benefit in chronic diseases such as coronary artery disease and chronic kidney disease, which has been termed the "obesity paradox". However, whether this phenomenon exists in trauma patients remains controversial. We performed a retrospective cohort study in abdominal trauma patients admitted to a Level I trauma center in Nanjing, China between 2010 and 2020. In addition to the traditional body mass index (BMI) based measures, we further examined the association between body composition-based indices with clinical severity in trauma populations. Body composition indices including skeletal muscle index (SMI), fat tissue index (FTI), and total fat-to-muscle ratio (FTI/SMI) were measured using computed tomography. Our study found that overweight was associated with a four-fold risk of mortality (OR, 4.47 [95% CI, 1.40-14.97], p = 0.012) and obesity was associated with a seven-fold risk of mortality (OR, 6.56 [95% CI, 1.07-36.57], p = 0.032) compared to normal weight. Patients with high FTI/SMI had a three-fold risk of mortality (OR, 3.06 [95% CI, 1.08-10.16], p = 0.046) and double the risk of an intensive care unit length of stay ≥ 5 d (OR, 1.75 [95% CI, 1.06-2.91], p = 0.031) compared to patients with low FTI/SMI. The obesity paradox was not observed in abdominal trauma patients, and high FTI/SMI ratio was independently associated with increased clinical severity.

Akkermansia muciniphila Alleviates Persistent Inflammation, Immunosuppression, and Catabolism Syndrome in Mice.

Many patients in intensive care units, especially the elderly, suffer from chronic critical illness and exhibit a new pathophysiological phenotype: persistent inflammation, immunosuppression, and catabolism syndrome (PICS). Most patients with PICS have a constellation of digestive-system symptoms and gut failure. Akkermansia muciniphila (Akk) is a commensal gut bacterium that reduces inflammation, balances immune responses, modulates energy metabolism, and supports gut health. This study investigated the protective effects and underlying mechanisms of live and pasteurized Akk in treating PICS in a mouse model. PICS was induced on day 14 after performing cecal ligation and puncture (CLP) on day 1 and administrating lipopolysaccharide on day 11. Pasteurized or live Akk, or phosphate-buffered saline was administered twice daily by oral gavage for 7 days. Both live and pasteurized Akk attenuated PICS, as evidenced by reduced weight loss, and a reduction in symptoms and serum cytokine/chemokine levels. Liver and intestinal injuries were mitigated, and intestinal barrier integrity improved with Akk administration. Analysis of 16S rRNA amplicon sequences showed that Akk induced significant intestinal microbiota alterations, including increased abundance of Akk, Muribaculaceae, Parabacterbides goldsteinii, and decreased abundance of Escherichia_Shigella and Enterobacteriaceae. Collectively, Akk alleviates PICS by enhancing gut barrier function and reshaped the microbial community.

Early parenteral nutrition comparing to enteral nutrition cannot reduce 28-day mortality in critically ill patients: a retrospective comparative cohort study based on the MIMIC­IV database.

Background: Enteral nutrition (EN) is recommended as the first choice by guidelines for critical ill patients. But the timing of safe and effective delivery of parenteral nutrition (PN) is unclear and the results of previous studies are controversial. There is insufficient evidence for the use of early PN, so we designed this cohort study to compared the clinical outcomes of critical ill patients who received early PN with those who did not. Methods: This retrospective study conducted using the Medical Information Mart for Intensive Care (MIMIC)-IV database. Patients who received nutrition therapy within 3 days of ICU admission were included and we categorized them as patients who received any kind of PN (PN group) or only enteral nutrition (EN group). Confounding factors were adjusted by propensity-score matching (PSM). The primary outcome was the 28-day mortality rate, and secondary outcomes included length of stay (LOS) in the hospital and ICU, hospital infection, and mechanical ventilation time. Results: A total of 5,019 patients (PN group, 357; EN group, 4,662) were included in the analyses. The 28-day mortality rates showed no significant intergroup difference (EN, 22.3% vs. PN, 20.2%; P=0.378). The PN group showed a shorter median ICU LOS (EN, 8.14 vs. PN, 6.89 days, P=0.00955), and a longer median hospital LOS (PN, 21.55 vs. EN, 15.1 days, P<0.001). After PSM, each group included 355 patients, with no significant intergroup difference in the 28-day mortality rate (EN, 18.9% vs. PN, 20.3%; P=0.705). The PN group still showed a longer hospital LOS (median LOS: PN, 21.45 vs. EN, 14.81 days, P<0.001), but the other outcomes showed no differences. Conclusions: PN within 3 days of ICU admission did not reduce the 28-day mortality rate and could extend hospital LOS. This study supports further fundamental and clinical research to ascertain the effect of PN for ICU patients.