Plasma metabolomics and proteomics profiling after a postprandial challenge reveal subtle diet effects on human metabolic status

Abstract

We introduce the metabolomics and proteomics based Postprandial Challenge Test (PCT) to quantify the postprandial response of multiple metabolic processes in humans in a standardized manner. The PCT comprised consumption of a standardized 500 ml dairy shake containing respectively 59, 30 and 12 energy percent lipids, carbohydrates and protein. During a 6 h time course after PCT 145 plasma metabolites, 79 proteins and 7 clinical chemistry parameters were quantified. Multiple processes related to metabolism, oxidation and inflammation reacted to the PCT, as demonstrated by changes of 106 metabolites, 31 proteins and 5 clinical chemistry parameters. The PCT was applied in a dietary intervention study to evaluate if the PCT would reveal additional metabolic changes compared to non-perturbed conditions. The study consisted of a 5-week intervention with a supplement mix of anti-inflammatory compounds in a crossover design with 36 overweight subjects. Of the 231 quantified parameters, 31 had different responses over time between treated and control groups, revealing differences in amino acid metabolism, oxidative stress, inflammation and endocrine metabolism. The results showed that the acute, short term metabolic responses to the PCT were different in subjects on the supplement mix compared to the controls. The PCT provided additional metabolic changes related to the dietary intervention not observed in non-perturbed conditions. Thus, a metabolomics based quantification of a standardized perturbation of metabolic homeostasis is more informative on metabolic status and subtle health effects induced by (dietary) interventions than quantification of the homeostatic situation. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11306-011-0320-5) contains supplementary material, which is available to authorized users.

Figures

Fig. 1

The six different observed postprandial time course profiles. a The time cluster profiles represented by the 142 different plasma metabolites and proteins with a significant effect of time. The red line represents the average cluster time profile. The x-axes were expressed as time (hours), the y-axes were expressed as relatively scaled concentrations. Time profile cluster 1 represented 21 plasma parameters with a classical absorption profile, reaching maximum values after 1–2 h, followed by a continued reduction towards minimal values at the final (6 h) time point. Time profile cluster 2, including 44 parameters, was similar to cluster 1, with the main difference that parameters in cluster 2 reached minimum values around 4 h after postprandial challenge. Thus, the time profile clusters 1 and 2 mainly differ in the duration of the response (4 or 6 h after postprandial challenge). Time profile cluster 3 represented the parameters that decreased upon the PCT, with a subsequent recovery phase. The average time required to reach lowest plasma concentrations is 2–3 h. This cluster contained 24 parameters with a significant time effect. Time profile cluster 4 (19 parameters) included parameters that steadily decreased during the 6 h time course. Time profile cluster 5 represented 16 plasma parameters that increased during most of the 6 h time course. The average time required to reach highest plasma concentrations was ~4 h. Finally, time profile cluster 6 included 18 parameters with a continuous increase in plasma concentration after an initial lag phase of approximately two hours. b The different time profile clusters summarized in one figure (Color figure online)

Fig. 2

Responses to PCT after AIDM and placebo intervention. Figures show mean (±SEM) difference versus t0 for each time point. Differences versus t0 were calculated for 35 (metabolites) or 33 subjects (proteins). Diamond indicates placebo intervention and square indicates AIDM intervention. MDC Macrophage-derived chemokine, VCAM-1 vascular cell adhesion protein 1, vWF von Willebrand factor. Y-axis are relative concentrations for metabolites C22:6 fatty acid and lactose; for proteins units for difference in concentration (compared to t0) are as follows: MDC pg/ml, VCAM-1 ng/ml, fibrinogen mg/ml, vWF μg/ml and glucagon pg/ml

Fig. 3

Network showing connections between endocrine factors with a differential response to PCT after AIDM intervention compared to placebo (MetaCore, network option auto expand)