Lupus pathogenesis and autoimmunity are exacerbated by high fat diet-induced obesity in MRL/lpr mice

Objective SLE is an autoimmune disease characterised by persistent inflammation and autoantibody production. Genetic predisposition and environmental factors such as a high-fat diet (HFD) may contribute to lupus development. However, the immune cell profile and gender difference in response to HFD in lupus have not been reported. Here we investigated the impact of HFD on lupus pathogenesis and autoimmunity using lupus-prone mice.Methods Thirty male and 30 female MRL/lymphoproliferation (lpr) mice were fed with regular diet (RD) or HFD. Body weights were recorded weekly. SLE progression was monitored by skin lesion, urine protein, titres of antidouble-strand DNA (dsDNA) and ANA. At week 14, kidney and skin tissue sections were stained with H&E and periodic acid–Schiff to detect histological kidney index and skin score. Splenocytes were identified by immunofluorescence staining and flow cytometry.Results HFD significantly increased body weight and lipid levels compared with RD (p<0.01). Skin lesions were observed in 55.6% of the HFD group compared with 11.1% of the RD group, with greater histopathological skin scores in the female HFD group (p<0.01). Although both male and female mice had higher serum IgG in the HFD group than in the RD group, only the male HFD group showed an increased trend in anti-dsDNA Ab and ANA titres. Kidney pathological changes in the HFD group were more severe in male mice than in female mice (p<0.05), detected by proteinuria, kidney index and glomerular cell proliferation. Significant increases of germinal centre B cells and T follicular helper cells were observed in the spleens of HFD mice (p<0.05).Conclusion HFD induced an accelerated and exacerbated lupus development and autoimmunity in MRL/lpr mice. Our results parallel many known clinical lupus phenotypes and sexual dimorphism in which male patients are likelier to have a severe disease (nephritis) than female lupus patients who may have a broader range of lupus symptoms

LXR ligand lowers LDL cholesterol in primates, is lipid neutral in hamster, and reduces atherosclerosis in mouse[S]

Liver X receptors (LXRs) are ligand-activated transcription factors that coordinate regulation of gene expression involved in several cellular functions but most notably cholesterol homeostasis encompassing cholesterol transport, catabolism, and absorption. WAY-252623 (LXR-623) is a highly selective and orally bioavailable synthetic modulator of LXR, which demonstrated efficacy for reducing lesion progression in the murine LDLR−/− atherosclerosis model with no associated increase in hepatic lipogenesis either in this model or Syrian hamsters. In nonhuman primates with normal lipid levels, WAY-252623 significantly reduced total (50–55%) and LDL-cholesterol (LDLc) (70–77%) in a time- and dose-dependent manner as well as increased expression of the target genes ABCA1/G1 in peripheral blood cells. Statistically significant decreases in LDLc were noted as early as day 7, reached a maximum by day 28, and exceeded reductions observed for simvastatin alone (20 mg/kg). Transient increases in circulating triglycerides and liver enzymes reverted to baseline levels over the course of the study. Complementary microarray analysis of duodenum and liver gene expression revealed differential activation of LXR target genes and suggested no direct activation of hepatic lipogenesis

Environmental and societal factors associated with COVID-19-related death in people with rheumatic disease: an observational study

Published by Elsevier Ltd.Background: Differences in the distribution of individual-level clinical risk factors across regions do not fully explain the observed global disparities in COVID-19 outcomes. We aimed to investigate the associations between environmental and societal factors and country-level variations in mortality attributed to COVID-19 among people with rheumatic disease globally. Methods: In this observational study, we derived individual-level data on adults (aged 18-99 years) with rheumatic disease and a confirmed status of their highest COVID-19 severity level from the COVID-19 Global Rheumatology Alliance (GRA) registry, collected between March 12, 2020, and Aug 27, 2021. Environmental and societal factors were obtained from publicly available sources. The primary endpoint was mortality attributed to COVID-19. We used a multivariable logistic regression to evaluate independent associations between environmental and societal factors and death, after controlling for individual-level risk factors. We used a series of nested mixed-effects models to establish whether environmental and societal factors sufficiently explained country-level variations in death. Findings: 14 044 patients from 23 countries were included in the analyses. 10 178 (72·5%) individuals were female and 3866 (27·5%) were male, with a mean age of 54·4 years (SD 15·6). Air pollution (odds ratio 1·10 per 10 μg/m3 [95% CI 1·01-1·17]; p=0·0105), proportion of the population aged 65 years or older (1·19 per 1% increase [1·10-1·30]; p<0·0001), and population mobility (1·03 per 1% increase in number of visits to grocery and pharmacy stores [1·02-1·05]; p<0·0001 and 1·02 per 1% increase in number of visits to workplaces [1·00-1·03]; p=0·032) were independently associated with higher odds of mortality. Number of hospital beds (0·94 per 1-unit increase per 1000 people [0·88-1·00]; p=0·046), human development index (0·65 per 0·1-unit increase [0·44-0·96]; p=0·032), government response stringency (0·83 per 10-unit increase in containment index [0·74-0·93]; p=0·0018), as well as follow-up time (0·78 per month [0·69-0·88]; p<0·0001) were independently associated with lower odds of mortality. These factors sufficiently explained country-level variations in death attributable to COVID-19 (intraclass correlation coefficient 1·2% [0·1-9·5]; p=0·14). Interpretation: Our findings highlight the importance of environmental and societal factors as potential explanations of the observed regional disparities in COVID-19 outcomes among people with rheumatic disease and lay foundation for a new research agenda to address these disparities.MAG is supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases (grant numbers K01 AR070585 and K24 AR074534 [JY]). KDW is supported by the Department of Veterans Affairs and the Rheumatology Research Foundation Scientist Development award. JAS is supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases (grant numbers K23 AR069688, R03 AR075886, L30 AR066953, P30 AR070253, and P30 AR072577), the Rheumatology Research Foundation (K Supplement Award and R Bridge Award), the Brigham Research Institute, and the R. Bruce and Joan M. Mickey Research Scholar Fund. NJP is supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases (T32-AR-007258). AD-G is supported by grants from the Centers for Disease Control and Prevention and the Rheumatology Research Foundation. RH was supported by the Justus-Liebig University Giessen Clinician Scientist Program in Biomedical Research to work on this registry. JY is supported by grants from the National Institutes of Health (K24 AR074534 and P30 AR070155).info:eu-repo/semantics/publishedVersio