New insight into the mechanism of POP-induced obesity: Evidence from DDE-altered microbiota

Although epidemiological studies demonstrate that persistent organic pollutants (POPs) could lead to metabolic syndrome, the mechanism has remained unclear. The dysbiosis of gut microbiota and the lipid metabolome have been put forward in the pathophysiology of metabolic syndrome. In this study, we used dichlorodiphenyldichloroethylene (DDE) as an example to study the effects of POP-impaired microbial composition and metabolome homeostasis on metabolic syndrome. The results showed that DDE exposure increased body weight and fat content and impaired glucose homeostasis. Further investigation revealed that DDE induced gut dysbiosis as indicated by an increased Firmicutes-to-Bacteroidetes ratio, which may impact energy harvest efficiency. Meanwhile, the plasma lipid metabolome profile was significantly altered by DDE. Furthermore, phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, and triacylglycerol were identified as key metabolites affected by DDE treatment, and these altered lipid metabolites were highly correlated with changed microbiota composition. This study provides novel insight into the underlying mechanism of POP-induced obesity and diabetes, pointing to gut microbiota as one of the targets.

Changes in lipid classes of Drosophila melanogaster in response to selection for three stress traits

Laboratory selection on environmental stress traits is an evolutionary approach that is informative in the context of understanding stress adaptation. Here we characterize changes in a lipidome of Drosophila melanogaster in lines selected for increased heat (elevated heat knockdown refractoriness), cold (decreased time to recover from chill-coma) and desiccation survival. Selection for desiccation resistance resulted in changes in multiple lipid classes used to characterize a lipidome. This included a decrease in triacylglycerols (TAGs) which is relevant to interpretation of storage lipid levels in previous D. melanogaster desiccation survival selection experiments. Chill-coma recovery rate selection was expected to show extensive changes in lipid classes, but only phosphatidic acids exhibited significant change. Selection for increased heat knockdown resistance resulted in a substantial change in the abundance of a class of lipids (diacylglycerols) which could play a role in mediating the heat shock response or result in an increase in neutral lipid mobilization.

Causal role of lipid metabolome on the risk of ischemic stroke, its etiological subtypes, and long-term outcome: A Mendelian randomization study

BACKGROUND AND AIMS

The lipid profile is consistently associated with coronary artery disease (CAD) and ischemic stroke (IS). However, the lipoprotein subfractions have not been deeply explored in stroke subtypes, especially in IS outcome.

METHODS

We performed two-sample Mendelian randomization (MR) analysis using 92 lipid traits measured by nuclear magnetic resonance in 115,000 subjects from the UK Biobank. Data for genetic associations with IS, its subtypes, and long-term outcome (LTO) were obtained from three cohorts of European ancestry: GIGASTROKE (73,652 cases, 1,234,808 controls), GODS (n = 1791) and GISCOME (n = 6165). Results obtained using CARDIoGRAMPlusC4D were used to identify differences with CAD.

RESULTS

Genetically determined low concentration of medium high-density lipoprotein (HDL) particles (odds ratio (OR) = 0.92, 95% CI 0.88-0.96; p = 3.6 × 10-4) and its cholesterol content (OR = 0.92, 95% CI 0.88-0.96; p = 1.9 × 10-4) showed causal associations with an increased risk of stroke. Genetic predisposition to high apolipoprotein (apo)B to apoA-I ratio was causally associated with an increased risk of IS (OR = 1.12, 95% CI 1.06-1.18, p = 1.1 × 10-4), and a highly suggestive association was found between non-esterified cholesterol in low-density lipoprotein (LDL) and increased risk of atherothrombotic stroke (LAS) (OR = 1.35, 95% CI 1.10-1.66; p = 4.0 × 10-3). Low cholesterol in small and medium LDL was suggestively associated with poor LTO.

CONCLUSIONS

Our results support that low medium HDL concentration was causally associated with an increased stroke risk, while high levels of non-esterified cholesterol in LDL were suggestively associated with an increased risk of LAS and with a better LTO.