Insight in modulation of inflammation in response to diclofenac intervention: a human intervention study

Abstract

Background: Chronic systemic low-grade inflammation in obese subjects is associated with health complications including cardiovascular diseases, insulin resistance and diabetes. Reducing inflammatory responses may reduce these risks. However, available markers of inflammatory status inadequately describe the complexity of metabolic responses to mild anti-inflammatory therapy.

Methods: To address this limitation, we used an integrative omics approach to characterize modulation of inflammation in overweight men during an intervention with the non-steroidal anti-inflammatory drug diclofenac. Measured parameters included 80 plasma proteins, >300 plasma metabolites (lipids, free fatty acids, oxylipids and polar compounds) and an array of peripheral blood mononuclear cells (PBMC) gene expression products. These measures were submitted to multivariate and correlation analysis and were used for construction of biological response networks.

Results: A panel of genes, proteins and metabolites, including PGE2 and TNF-alpha, were identified that describe a diclofenac-response network (68 genes in PBMC, 1 plasma protein and 4 plasma metabolites). Novel candidate markers of inflammatory modulation included PBMC expression of annexin A1 and caspase 8, and the arachidonic acid metabolite 5,6-DHET.

Conclusion: In this study the integrated analysis of a wide range of parameters allowed the development of a network of markers responding to inflammatory modulation, thereby providing insight into the complex process of inflammation and ways to assess changes in inflammatory status associated with obesity.

Trial registration: The study is registered as NCT00221052 in clinicaltrials.gov database.

Figure 1

PGE2 levels before (day0) and after (day9) supplementation with placebo and diclofenac. The PGE2 response was significantly different for diclofenac compared to placebo (ANOVA, treatment * time interaction P < 0.05). In the diclofenac group, the difference in PGE2 level between day 9 and day 0 was significant (p-value = 0.0469).

Figure 2

CRP levels before (day0) and after (day9) supplementation with placebo and diclofenac. The CRP response was significantly different for diclofenac compared to placebo (ANOVA, treatment * time interaction P < 0.05). In the placebo group, hsCRP levels were significantly different at day 9 compared to day 0 (P = 0.0062).

Figure 3

Heatmap of responses of 68 genes, 1 protein (P) and 4 metabolites (M) to diclofenac intervention. Numbers represent % change in each subject in response to diclofenac. Each row lists identifier and name. For genes identifiers are Affymetrix probeset IDs, for proteins and metabolites names are shown followed by (P) or (M), respectively.

Figure 4

Network of response related to diclofenac intervention, generated using MapEditor from GeneGo Inc. * indicates markers measured in the current study. Arrow pointing upward indicates increase in response to diclofenac treatment, arrow pointing downward indicates decrease in response to diclofenac treatment. PLA2: phospholipase A2; ANXA1: annexin A1; COX2: cyclooxygenase 2; 20-HETE: 20-hydroxyeicosatetraenoic acid; 5,6-EET: 5(6)-epoxyeicosatrienoic acid; 5,6-DHET: 5,6-dihydroxy-eicosatrienoic acid; PGG1: prostaglandin G1; PGE1: prostaglandin E1; PGES: prostaglandin E synthase; TCR: T cell receptor; MALT1: mucosa-associated lymphoid tissue lymphoma translocation protein 1; BNIP-XL: Protein prune homolog 2; LBC: A-kinase anchor protein 13 (AKAP13). IE: influence on expression, B: binding.