Metabolomics Reveal Altered Postprandial Lipid Metabolism After a High-Carbohydrate Meal in Men at High Genetic Risk of Diabetes

BACKGROUND

The transcription factor 7-like 2 (TCF7L2) gene confers one of the strongest genetic predispositions to type 2 diabetes, but diabetes development can be modified by diet.

OBJECTIVE

The aim of our study was to evaluate postprandial metabolic alterations in healthy men with a high genetic risk of diabetes, after two meals with varying macronutrient content.

METHODS

The study was conducted in 21 homozygous nondiabetic men carrying the high-risk (HR, n = 8, age: 31.2 ± 6.3 y, body mass index (BMI, kg/m2) 28.5 ± 8.1) or low-risk (LR, n = 13, age: 35.2 ± 10.3 y, BMI: 28.1 ± 6.4) genotypes at the rs7901695 locus. During two meal challenge test visits subjects received standardized isocaloric (450 kcal) liquid meals: high-carbohydrate (HC, carbohydrates: 89% of energy) and normo-carbohydrate (NC, carbohydrates: 45% of energy). Fasting (0 min) and postprandial (30, 60, 120, 180 min) plasma samples were analyzed for metabolite profiles through untargeted metabolomics. Metabolic fingerprinting was performed on an ultra-high-performance liquid chromatography (UHPLC) system connected to an iFunnel quadrupole-time-of-flight (Q-TOF) mass spectrometer.

RESULTS

In HR-genotype men, after the intake of an HC-meal, we noted a significantly lower area under the curves (AUCs) of postprandial plasma concentrations of most of the phospholipids (-37% to -53%, variable importance in the projection (VIP) = 1.2-1.5), lysophospholipids (-29% to -86%, VIP = 1.1-2.6), sphingolipids (-32% to -47%, VIP = 1.1-1.3), as well as arachidonic (-36%, VIP = 1.4) and oleic (-63%, VIP = 1.3) acids, their metabolites: keto- and hydoxy-fatty acids (-38% to -78%, VIP = 1.3-2.5), leukotrienes (-65% to -83%, VIP = 1.4-2.2), uric acid (-59%, VIP = 1.5), and pyroglutamic acid (-65%, VIP = 1.8). The AUCs of postprandial sphingosine concentrations were higher (125-832%, VIP = 1.9-3.2) after the NC-meal, AUCs of acylcarnitines were lower (-21% to -61%, VIP = 1.1-2.4), and AUCs of fatty acid amides were higher (51-508%, VIP = 1.7-3.1) after the intake of both meals.

CONCLUSIONS

In nondiabetic men carrying the TCF7L2 HR genotype, subtle but detectable modifications in intermediate lipid metabolism are induced by an HC-meal. This trial was registered at www.clinicaltrials.gov as NCT03792685.

The Type 2 Diabetes Susceptibility PROX1 Gene Variants Are Associated with Postprandial Plasma Metabolites Profile in Non-Diabetic Men

The prospero homeobox 1 (PROX1) gene may show pleiotropic effects on metabolism. We evaluated postprandial metabolic alterations dependently on the rs340874 genotypes, and 28 non-diabetic men were divided into two groups: high-risk (HR)-genotype (CC-genotype carriers, n = 12, 35.3 ± 9.5 years old) and low-risk (LR)-genotype (allele T carriers, n = 16, 36.3 ± 7.0 years old). Subjects participated in two meal-challenge-tests with high-carbohydrate (HC, carbohydrates 89%) and normo-carbohydrate (NC, carbohydrates 45%) meal intake. Fasting and 30, 60, 120, and 180 min after meal intake plasma samples were fingerprinted by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). In HR-genotype men, the area under the curve (AUC) of acetylcarnitine levels was higher after the HC-meal [+92%, variable importance in the projection (VIP) = 2.88] and the NC-meal (+55%, VIP = 2.00) intake. After the NC-meal, the HR-risk genotype carriers presented lower AUCs of oxidized fatty acids (−81–66%, VIP = 1.43–3.16) and higher linoleic acid (+80%, VIP = 2.29), while after the HC-meal, they presented lower AUCs of ornithine (−45%, VIP = 1.83), sphingosine (−48%, VIP = 2.78), linoleamide (−45%, VIP = 1.51), and several lysophospholipids (−40–56%, VIP = 1.72–2.16). Moreover, lower AUC (−59%, VIP = 2.43) of taurocholate after the HC-meal and higher (+70%, VIP = 1.42) glycodeoxycholate levels after the NC-meal were observed. Our results revealed differences in postprandial metabolites from inflammatory and oxidative stress pathways, bile acids signaling, and lipid metabolism in PROX1 HR-genotype men. Further investigations of diet–genes interactions by which PROX1 may promote T2DM development are needed.