Glucose challenge metabolomics implicates medium-chain acylcarnitines in insulin resistance.
Christoph NowakSusanne HettySamira SalihovicCasimiro Castillejo-LopezAndrea GannaNaomi L CookCorey D BroecklingJessica E PrenniXia ShenVilmantas GiedraitisJohan ÄrnlövLars LindChristian BerneJohan SundströmChristoph NowakErik IngelssonPublished in: Scientific reports (2018)
Insulin resistance (IR) predisposes to type 2 diabetes and cardiovascular disease but its causes are incompletely understood. Metabolic challenges like the oral glucose tolerance test (OGTT) can reveal pathogenic mechanisms. We aimed to discover associations of IR with metabolite trajectories during OGTT. In 470 non-diabetic men (age 70.6 ± 0.6 years), plasma samples obtained at 0, 30 and 120 minutes during an OGTT were analyzed by untargeted liquid chromatography-mass spectrometry metabolomics. IR was assessed with the hyperinsulinemic-euglycemic clamp method. We applied age-adjusted linear regression to identify metabolites whose concentration change was related to IR. Nine trajectories, including monounsaturated fatty acids, lysophosphatidylethanolamines and a bile acid, were significantly associated with IR, with the strongest associations observed for medium-chain acylcarnitines C10 and C12, and no associations with L-carnitine or C2-, C8-, C14- or C16-carnitine. Concentrations of C10- and C12-carnitine decreased during OGTT with a blunted decline in participants with worse insulin resistance. Associations persisted after adjustment for obesity, fasting insulin and fasting glucose. In mouse 3T3-L1 adipocytes exposed to different acylcarnitines, we observed blunted insulin-stimulated glucose uptake after treatment with C10- or C12-carnitine. In conclusion, our results identify medium-chain acylcarnitines as possible contributors to IR.
Keyphrases
- insulin resistance
- type diabetes
- mass spectrometry
- liquid chromatography
- glycemic control
- blood glucose
- adipose tissue
- high fat diet induced
- cardiovascular disease
- high fat diet
- metabolic syndrome
- polycystic ovary syndrome
- skeletal muscle
- depressive symptoms
- high resolution mass spectrometry
- fatty acid
- high resolution
- gas chromatography
- single cell
- gene expression
- dna methylation
- physical activity
- body mass index
- capillary electrophoresis
- middle aged
- coronary artery disease