Phosphatidylcholine (PC) is the most abundant phospholipid in natural products and exhibits various bioactivities in vivo. However, the beneficial effects of PC on IR and the potential mechanisms are rarely reported. PCs from different biological sources vary greatly in their fatty acid compositions. The present study aimed to investigate the effect of EPA/DHA-PC derived from Sthenototeuthis oualaniensis on high fat diet (HFD)-induced IR in comparison with terrestrial soybean PC (Soy-PC) and egg yolk PC (Egg-PC) in C57BL/6J mice. The results indicated that EPA/DHA-PC, but not Soy-PC or Egg-PC, reversed HFD-induced obesity, IR and hyperglycemia. This improvement was accompanied by enhanced IRS/PI3K/AKT insulin signaling pathway in peripheral tissue, ameliorated JNK and NF-κB inflammatory pathway in white adipose tissue, and changes in the gut microbial composition. Microbiological analysis showed that EPA/DHA-PC treatment prevented the loss of Bacteroidetes, Verrucomicrobia, Akkermansia, Coriobacteriaceae_UCG-002, Lactobacillus, Clostridium_sensu_stricto_1, Bacteroides and inhibited the increase of Firmicutes, Actinobacteria, Proteobacteria, and Ileibacterium. The gut microbiota-derived metabolites LPS and TMAO were also reduced by EPA/DHA-PC. In summary, the improvement effect of PCs on IR is largely related to their fatty acid composition. EPA/DHA-PC prevented IR probably by modulating the gut microbiota composition, ameliorating the chronic inflammation in the adipose tissue and promoting transduction of insulin signaling pathways.

Diabetic cardiomyopathy (DCM) is a common complication of diabetes mellitus (DM), resulting in high mortality. Myocardial fibrosis, cardiomyocyte apoptosis and inflammatory cell infiltration are hallmarks of DCM, leading to cardiac dysfunction. To date, few effective approaches have been developed for the intervention of DCM. In the present study, we investigate the effect of krill oil (KO) on the prevention of DCM using a mouse model of DM induced by streptozotocin and a high-fat diet. The diabetic mice developed pathological features, including cardiac fibrosis, apoptosis and inflammatory cell infiltration, the effects of which were remarkably prevented by KO. Mechanistically, KO reversed the DM-induced cardiac expression of profibrotic and proinflammatory genes and attenuated DM-enhanced cardiac oxidative stress. Notably, KO exhibited a potent inhibitory effect on NLR family pyrin domain containing 3 (NLRP3) inflammasome that plays an important role in DCM. Further investigation showed that KO significantly upregulated the expression of Sirtuin 3 (SIRT3) and peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α), which are negative regulators of NLRP3. The present study reports for the first time the preventive effect of KO on the pathological injuries of DCM, providing SIRT3, PGC-1α and NLRP3 as molecular targets of KO. This work suggests that KO supplementation may be a viable approach in clinical prevention of DCM.

High-fat and high-sucrose diet (HFHSD)-induced obesity leads to oxidative stress and chronic inflammatory status. However, little is known about the beneficial effects of total lipids extracted from Spirulina. Hence, in the present study, Spirulina lipids were extracted with chloroform/methanol (SLC) or ethanol (SLE) and then their effects on oxidative stress and inflammation in the mice fed a HFHSD were investigated. The results show that the major lipid classes and fatty acid profiles of SLC and SLE were almost similar, but the gamma-linolenic acid (GLA) and carotenoid contents in SLE was a little higher than that in SLC. Dietary 4% SLC or SLE for 12 weeks effectively decreased the hepatic lipid hydroperoxide levels as well as increased the activities and mRNA levels of antioxidant enzymes in the mice fed a HFHSD. In addition, supplementation with SLC and SLE also markedly decreased the levels of serum pro-inflammatory cytokines and the mRNA expression of pro-inflammatory cytokines in the liver and epididymal white adipose tissue of mice fed a HFHSD, and the effects of SLC and SLE were comparable. These findings confirm for the first time that dietary Spirulina lipids could alleviate HFHSD-induced oxidative stress and inflammation.