The association of specific metabolites of lipid metabolism with markers of oxidative stress, inflammation and arterial stiffness in men with newly diagnosed type 2 diabetes

Objective To determine whether circulating metabolic intermediates are associated with inflammation, oxidative stress and arterial stiffness in men with newly diagnosed type 2 diabetes and investigate the circulating metabolic intermediates that may predict the risk of developing diabetes. Research design and methods Men with newly diagnosed type 2 diabetes (n = 26) and age-and body mass index-matched nondiabetic men (n = 27) were included. We measured inflammatory and oxidative markers and arterial stiffness by brachial-ankle pulse wave velocity (ba-PWV). Metabolomic profiling was analysed with ultra performance liquid chromatography and quadrupole time-of-flight mass spectrometry. Results Diabetic men showed higher circulating levels of glucose, triglyceride, oxidized low-density lipoprotein (LDL), high-sensitivity C-reactive protein, interleukin (IL)-6, tumour necrosis factor-alpha (TNF-alpha), homeostasis model assessment-insulin resistance, urinary 8-epi-prostaglandin F-2 alpha (8-epi-PGF(2 alpha)) and ba-PWV than nondiabetic men. In plasma, 19 metabolites including three amino acids, eight acylcarnitines, six lysophosphatidylcholines (lysoPCs), and two lysophosphatidylethanolamines (lysoPEs; C18:2 and C22:6) significantly increased in diabetes men, whereas serine and lysoPE (C18: 1) decreased. Decanoyl carnitine, lysoPCs (C14:0, C16:1, C18: 1 and C22: 6) and lysoPE (C18: 1) with variable importance in the projection values >1.0 were major plasma metabolites that distinguished nondiabetic and diabetic men. Decanoyl carnitine positively correlated with oxidized LDL, 8-epi-PGF(2 alpha), IL-6, TNF-a and ba-PWV. ba-PWV correlated positively with lysoPCs C14: 0 and C16: 1, and negatively with lysoPE C18:1. 8-epi-PGF2 alpha correlated positively with lipoprotein-associated phospholipase A(2), ba-PWV and lysoPCs (C14:0 and C16:1). The receiver operating characteristic curve estimation suggested that decanoyl carnitine and lysoPC (C14:0) are the best metabolites for predicting the risk of developing diabetes. Conclusions Circulating lipid-related intermediate metabolites can be closely associated with inflammation, oxidative stress and arterial stiffness in early diabetes.