How multiple air pollutants affect hand, foot, and mouth disease incidence in children: assessing effect modification by geographical context in multicity of Sichuan, southwest China.

BACKGROUND: Several studies have suggested a significant association of hand, foot, and mouth disease (HFMD) with ambient air pollutants. Existing studies have characterized the role of air pollutants on HFMD using only risk ratio measures while ignoring the attributable burden. And whether the geographical context (i.e., diverse topographic features) could modulate the relationships is unclear. METHODS: Daily reported childhood HFMD counts, ambient air pollution, and meteorological data during 2015-2017 were collected for each of 21 cities in Sichuan Province. A multistage analysis was carried out in different populations based on geographical context to assess effect modification by topographic conditions. We first constructed a distributed lag nonlinear model (DLNM) for each city to describe the relationships with risk ratio measures. Then, we applied a multivariate meta-regression to estimate the pooled effects of multiple air pollutants on HFMD from the exposure and lagged dimensions. Finally, attributable risks measures were calculated to quantify HFMD burden by air pollution. RESULTS: Based on 207554 HFMD cases in Sichuan Province, significant associations of HFMD with ambient air pollutants were observed mainly at relatively high exposure ranges. The effects of ambient air pollutants on HFMD are most pronounced on lag0 or around lag7, with relative risks gradually approaching the reference line thereafter. The attributable risks of O3 were much greater than those of other air pollutants, particularly in basin and mountain regions. CONCLUSIONS: This study revealed significant pooled relationships between multiple air pollutants and HFMD incidence from both exposure and lag dimensions. However, the specific effects, including RRs and ARs, differ depending on the air pollution variable and geographical context. These findings provide local authorities with more evidence to determine key air pollutants and regions for devising and implementing targeted interventions.

Semaglutide ameliorates hepatocyte steatosis in a cell co-culture system by downregulating the IRE1α-XBP1-C/EBPα signaling pathway in macrophages.

Non-alcoholic fatty liver disease (NAFLD) is currently the most common type of chronic liver disease. Semaglutide is a glucose-lowering drug administered for the treatment of type 2 diabetes mellitus (T2DM) and is clinically effective in the treatment of NAFLD. X-box binding protein 1 (XBP1) is related to the pathogenesis of both NAFLD and T2DM. The aim of the present study was to demonstrate whether the underlying mechanism of semaglutide treatment for NAFLD is via downregulation of the inositol-requiring transmembrane kinase/endonuclease-1α (IRE1α)-XBP1-CCAAT/enhancer binding protein α (C/EBPα) signaling pathway in macrophages. METHODS: In the present study, NAFLD cell modeling was induced by oleic acid (0.4 mM) and palmitic acid (0.2 mM). Hepatocytes (AML12) and macrophages (RAW264.7) were co-cultured in 6-well Transwell plates. Semaglutide (60 or 140 nM) was administrated for 24 h, while pioglitazone (2 µM) and toyocamycin (200 nM) were used as a positive control drug and a XBP1 inhibitor, respectively. Autophagy and apoptosis of AML12 cells were detected by transmission electron microscopy and western blotting (WB). Hepatocyte steatosis was evaluated using total intracellular triglyceride determination, analysis of the relative expression of proteins and genes associated with lipid metabolism and hepatocyte Oil red O staining. Detection of inflammation factors was conducted by ELISA and WB. To explore the underlying mechanism of NAFLD treatment with semaglutide, the relative expression of related proteins and genes were tested. RESULTS: Our study demonstrated that semaglutide treatment improved autophagy and inhibited apoptosis of hepatocytes, while notably ameliorating steatosis of hepatocytes. In addition, inflammation was attenuated in the NAFLD cell co-culture model after semaglutide administration. Semaglutide also significantly reduced the protein and gene expression levels of the IRE1α-XBP1-C/EBPα signaling pathway in macrophages. CONCLUSION: Semaglutide partially ameliorated NAFLD by down-regulating the IRE1α-XBP1-C/EBPα signaling pathway in macrophages. These findings may provide a potential theoretical basis for semaglutide therapy for NAFLD.