Plasma Sphingolipid Profile in Association with Incident Metabolic Syndrome in a Chinese Population-Based Cohort Study

New Advances in Metabolic Syndrome, from Prevention to Treatment: The Role of Diet and Food

The definition of metabolic syndrome (MetS) has undergone several changes over the years due to the difficulty in establishing universal criteria for it. Underlying the disorders related to MetS is almost invariably a pro-inflammatory state related to altered glucose metabolism, which could lead to elevated cardiovascular risk. Indeed, the complications closely related to MetS are cardiovascular diseases (CVDs) and type 2 diabetes (T2D). It has been observed that the predisposition to metabolic syndrome is modulated by complex interactions between human microbiota, genetic factors, and diet. This review provides a summary of the last decade of literature related to three principal aspects of MetS: (i) the syndrome's definition and classification, pathophysiology, and treatment approaches; (ii) prediction and diagnosis underlying the biomarkers identified by means of advanced methodologies (NMR, LC/GC-MS, and LC, LC-MS); and (iii) the role of foods and food components in prevention and/or treatment of MetS, demonstrating a possible role of specific foods intake in the development of MetS.

Metabolomic Changes Upon Conjugated Linoleic Acid Supplementation and Predictions of Body Composition Responsiveness

CONTEXT

Conjugated linoleic acid (CLA) may optimize body composition, yet mechanisms underlining its benefits are not clear in humans.

OBJECTIVE

We aimed to reveal the CLA-induced changes in the plasma metabolome associated with body composition improvement and the predictive performance of baseline metabolome on intervention responsiveness.

METHODS

Plasma metabolome from overnight fasted samples at pre- and post-intervention of 65 participants in a 12-week randomized, placebo-controlled trial (3.2 g/day CLA vs 3.2 g/day sunflower oil) were analyzed using untargeted LC-MS metabolomics. Mixed linear model and machine learning were applied to assess differential metabolites between treatments, and to identify optimal panel (based on baseline conventional variables vs metabolites) predicting responders of CLA-derived body composition improvement (increased muscle variables or decreased adiposity variables) based on dual-energy x-ray absorptiometry.

RESULTS

Compared with placebo, CLA altered 57 metabolites (P < 0.10) enriched in lipids/lipid-like molecules including glycerophospholipids (n = 7), fatty acyls (n = 6), and sphingolipids (n = 3). CLA-upregulated cholic acid (or downregulated aminopyrrolnitrin) was inversely correlated with changes in muscle and adiposity variables. Inter-individual variability in response to CLA-derived body composition change. The areas under the curves of optimal metabolite panels were higher than those of optimal conventional panels in predicting favorable response of waist circumference (0.93 [0.82-1.00] vs 0.64 [0.43-0.85]), visceral adiposity index (0.95 [0.88-1.00] vs 0.58 [0.35-0.80]), total fat mass (0.94 [0.86-1.00] vs 0.69 [0.51-0.88]) and appendicular fat mass (0.97 [0.92-1.00] vs 0.73 [0.55-0.91]) upon CLA supplementation (all FDR P < 0.05).

CONCLUSION

Post-intervention metabolite alterations were identified, involving in lipid/energy metabolism, associated with body composition changes. Baseline metabolite profiling enhanced the prediction accuracy for responsiveness of CLA-induced body composition benefits.

Ceramide metabolism mediates the impaired glucose homeostasis following short-term black carbon exposure: A targeted lipidomic analysis

BACKGROUND

Ambient particulate matter (PM), especially its carbonaceous composition black carbon (BC) increases cardiometabolic risks, yet the underlying mechanisms are incompletely understood. Ceramides (Cer; a class of sphingolipids) are biological intermediates in glucose metabolism.

OBJECTIVES

To explore whether Cer metabolism mediates impaired glucose homeostasis following short-term PM exposure.

METHODS

In a panel study in Beijing, China, 112 participants were followed-up between 2016 and 2017. Targeted lipidomic analyses quantified 26 sphingolipids in 387 plasma samples. Ambient BC and PM with aerodynamic diameter ≤ 2.5 μm (PM_2.5) were continuously monitored in a station. We examined the associations of sphingolipid levels with average BC and PM_2.5 concentrations 1-14 days before clinical visits using linear mixed-effects models, and explored the mediation effects of sphingolipids on PM-associated fasting blood glucose (FBG) difference using mediation analyses.

RESULTS

Increased levels of FBG and multiple sphingolipids in Cer metabolic pathways were associated with BC exposure in 1-14-day time window, but not with PM_2.5 exposure. For each 10 μg/m³ increase in the average BC concentration 1-14 days before the clinical visits, species in the Cer C24:1 pathway (Cer, dihydroceramide, hexosylceramide, lactosylceramide, and sphingomyelin C24:1) increased in levels ranging from 11.8% (95% confidence interval [CI]: -6.2-33.2) to 48.7% (95% CI: 8.8-103.4), as did the Cer C16:0, C18:0, and C20:0 metabolic pathway species, ranging from 3.2% (95% CI: -5.6-12.9) to 32.4% (95% CI: 7.0-63.8), respectively. The Cer C24:1 metabolic pathway species mediated 6.5-25.5% of the FBG increase associated with BC exposure in 9-day time window. The Cer C16:0, C18:0, and C20:0 metabolic pathway species mediated 5.4-26.2% of the BC-associated FBG difference.

CONCLUSIONS

In conclusion, Cer metabolism may mediate impaired glucose homeostasis following short-term BC exposure. The current findings are preliminary, which need to be corroborated by further studies.