ADAM17 Boosts Cholesterol Efflux and Downstream Effects of High-Density Lipoprotein on Inflammatory Pathways in Macrophages

Inflammatory, metabolic, and sex-dependent gene-regulatory dynamics of microglia and macrophages in neonatal hippocampus after hypoxia-ischemia

Neonatal hypoxia-ischemia (HI) is a major cause of perinatal death and long-term disabilities worldwide. Post-ischemic neuroinflammation plays a pivotal role in HI pathophysiology. In the present study, we investigated the temporal dynamics of microglia (CX3CR1GFP/+) and infiltrating macrophages (CCR2RFP/+) in the hippocampi of mice subjected to HI at postnatal day 9. Using inflammatory pathway and transcription factor (TF) analyses, we identified a distinct post-ischemic response in CCR2RFP/+ cells characterized by differential gene expression in sensome, homeostatic, matrisome, lipid metabolic, and inflammatory molecular signatures. Three days after injury, transcriptomic signatures of CX3CR1GFP/+ and CCR2RFP/+ cells isolated from hippocampi showed a partial convergence. Interestingly, microglia-specific genes in CX3CR1GFP/+ cells showed a sexual dimorphism, where expression returned to control levels in males but not in females during the experimental time frame. These results highlight the importance of further investigations on metabolic rewiring to pave the way for future interventions in asphyxiated neonates.

Neutrophil to albumin ratio: a biomarker in non-alcoholic fatty liver disease and with liver fibrosis

Objective

Given the high prevalence of non-alcoholic fatty liver disease (NAFLD) and its potential to progress to liver fibrosis, it is crucial to identify the presence of NAFLD in patients to guide their subsequent management. However, the current availability of non-invasive biomarkers for NAFLD remains limited. Therefore, further investigation is needed to identify and develop non-invasive biomarkers for NAFLD.

Methods

A retrospective analysis was conducted on 11,883 patients admitted to the Healthcare Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, from January 2016 to December 2019 and divided into NAFLD and non-NAFLD groups. Anthropometric and laboratory examination data were collected. The correlations between variables and NAFLD were evaluated using the student's t-test or Mann-Whitney U test and binary logistic regression analysis. The predictive ability of these variables for NAFLD was assessed using the areas under the curves (AUCs) of receiver operating characteristics.

Results

Among the included patients, 3,872 (32.58%) were diagnosed with NAFLD, with 386 (9.97%) individuals having liver fibrosis. Patients with NAFLD exhibited a higher proportion of males, elevated body mass index (BMI), and increased likelihood of hypertension, diabetes mellitus, and atherosclerosis. Logistic regression analysis identified the neutrophil to albumin ratio (NAR) as the most promising novel inflammation biomarkers, with the highest AUC value of 0.701, a cut-off value of 0.797, sensitivity of 69.40%, and specificity of 66.00% in identifying the risk of NAFLD. Moreover, NAR demonstrated superior predictive value in identifying NAFLD patients at risk of liver fibrosis, with an AUC value of 0.795, sensitivity of 71.30%, and specificity of 73.60% when NAR reached 1.285.

Conclusion

These findings highlight that the novel inflammatory biomarker, NAR, is a convenient and easily accessible non-invasive predictor for NAFLD and NAFLD with liver fibrosis.

sTREM2 is a plasma biomarker for human NASH and promotes hepatocyte lipid accumulation

BACKGROUND

Pathogenetic mechanisms of the progression of NAFL to advanced NASH coupled with potential noninvasive biomarkers and novel therapeutic targets are active areas of investigation. The recent finding that increased plasma levels of a protein shed by myeloid cells -soluble Triggering Receptor Expressed on Myeloid cells 2 (sTREM2) -may be a biomarker for NASH has received much interest. We aimed to test sTREM2 as a biomarker for human NASH and investigate the role of sTREM2 in the pathogenesis of NASH.

METHODS

We conducted studies in both humans (comparing patients with NASH vs. NAFL) and in mice (comparing different mouse models of NASH) involving measurements of TREM2 gene and protein expression levels in the liver as well as circulating sTREM2 levels in plasma. We investigated the pathogenetic role of sTREM2 in hepatic steatosis using primary hepatocytes and bone marrow derived macrophages.

RESULTS

RNA sequencing analysis of livers from patients with NASH or NAFL as well as livers from 2 mouse models of NASH revealed elevated TREM2 expression in patients/mice with NASH as compared with NAFL. Plasma levels of sTREM2 were significantly higher in a well-characterized cohort of patients with biopsy-proven NASH versus NAFL (area under receiver-operating curve 0.807). Mechanistic studies revealed that cocultures of primary hepatocytes and macrophages with an impaired ability to shed sTREM2 resulted in reduced hepatocyte lipid droplet formation on palmitate stimulation, an effect that was counteracted by the addition of exogenous sTREM2 chimeric protein. Conversely, exogenous sTREM2 chimeric protein increased lipid droplet formation, triglyceride content, and expression of the lipid transporter CD36 in hepatocytes. Furthermore, inhibition of CD36 markedly attenuated sTREM2-induced lipid droplet formation in mouse primary hepatocytes.

CONCLUSIONS

Elevated levels of sTREM2 due to TREM2 shedding may directly contribute to the pathogenesis of NAFLD by promoting hepatocyte lipid accumulation, as well as serving as a biomarker for distinguishing patients with NASH versus NAFL. Further investigation of sTREM2 as a clinically useful diagnostic biomarker and of the therapeutic effects of targeting sTREM2 in NASH is warranted.

The Remnant Lipoprotein Hypothesis of Diabetes-Associated Cardiovascular Disease

Both type 1 and type 2 diabetes are associated with an increased risk of atherosclerotic cardiovascular disease (CVD). Research based on human-first or bedside-to-bench approaches has provided new insights into likely mechanisms behind this increased risk. Although both forms of diabetes are associated with hyperglycemia, it is becoming increasingly clear that altered lipoprotein metabolism also plays a critical role in predicting CVD risk in people with diabetes. This review examines recent findings indicating that increased levels of circulating remnant lipoproteins could be a missing link between diabetes and CVD. Although CVD risk associated with diabetes is clearly multifactorial in nature, these findings suggest that we should increase efforts in evaluating whether remnant lipoproteins or the proteins that govern their metabolism are biomarkers of incident CVD in people living with diabetes and whether reducing remnant lipoproteins will prevent the increased CVD risk associated with diabetes.

Diabetes Suppresses Glucose Uptake and Glycolysis in Macrophages

This manuscript was sent to Joyce Bischoff, Guest Editor, for review by expert referees, editorial decision, and final disposition. Final decisions were approved by Jane Leopold, Guest Editor-in-Chief.

Diagnostic performance of novel inflammatory biomarkers based on ratios of laboratory indicators for nonalcoholic fatty liver disease

INTRODUCTION

There is few effective biomarkers for diagnosing nonalcoholic fatty liver disease (NAFLD) in clinical practice. This study was aimed to investigate the predictive ability of novel inflammatory biomarkers, including the monocyte to high-density lipoprotein cholesterol ratio (MHR), neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and lymphocyte to monocyte ratio (LMR), for NAFLD.

METHODS

A total of 4465 outpatients diagnosed with NAFLD and 3683 healthy controls were enrolled between May 2016 and November 2021 from the West China Hospital of Sichuan University, and anthropometric and laboratory examination data were collected. The two-sample Mann-Whitney U test and binary logistic regression analysis were used to evaluate the correlations between four inflammatory biomarkers and NAFLD. The areas under the curves (AUCs) of receiver operating characteristic were used to evaluate their predictive ability for NAFLD.

RESULTS

The MHR, NLR and LMR were higher in patients with NAFLD than in healthy controls (P<0.001), whereas the PLR was remarkably lower (P<0.001). The OR values of the MHR, NLR, PLR, and LMR were 1.599 (1.543-1.658), 1.250 (1.186-1.317), 0.987(0.986-0.988) and 1.111(1.083-1.139), respectively(P<0.001). After adjusting for confounding factors, MHR was still the most relevant risk factor for NAFLD compared with other inflammatory markers (P<0.001). The AUCs of the MHR, NLR, PLR, and LMR were as follows: 0.663 (0.651-0.675), 0.524 (0.512-0.537), 0.329 (0.318-0.341), and 0.543 (0.530-0.555), respectively (P<0.001). Furthermore, the diagnostic model combining the MHR with alanine aminotransferase, aspartate aminotransferase, total cholesterol, triglycerides, fasting blood glucose, creatinine, uric acid, and body mass index had the best AUC of 0.931 (0.925-0.936).

CONCLUSIONS

MHR was superior to NLR, PLR and LMR as an inflammatory biomarker in the prediction of NAFLD. When combined with relevant laboratory parameters, the MHR may improve the clinical noninvasive diagnosis of NAFLD.