Sphingolipid metabolism in type 2 diabetes and associated cardiovascular complications.

Sphingolipid metabolism is dysregulated in type 2 diabetes mellitus (T2DM); however, the focus of previous studies was mostly limited to ceramide (Cer), and only few studies have investigated other metabolites, including sphingosine-1 phosphate (So1P). The present study aimed to examine the involvement of 8 major sphingolipid metabolites, including Cer, glucosyl ceramide (GluCer), lactosyl ceramide (LacCer), sphingomyelin (SM), sphinganine (Sa), So1P, sphingosine (So) and sphinganine-1-phosphate (Sa1P), during the progression of T2DM, and to evaluate the ability of serum sphingolipids to predict cases of diabetes with an elevated risk of cardiovascular complications. Blood samples were obtained from 245 participants who were divided into 3 groups: Healthy controls, pre-diabetes (pre-DM) and diagnosed diabetes. The 8 major sphingolipid metabolites were measured by high-performance liquid chromatography-tandem mass spectrometry and blood parameters were determined by routine laboratory assays for all subjects. Among the sphingolipid metabolites, So1P was associated with sex and lean mass index, but not with the body mass index. So1P was highest in healthy controls and gradually decreased when the disease proceeded to pre-DM and T2DM. GluCer, SM, Sa and So decreased in pre-DM and rose again in T2DM, graphically exhibiting a 'U' shape change during the progression of diabetes. So1P and Sa were identified to be significantly associated with cardiovascular complications by multivariate logistic regression analysis. Receiver operating characteristic curve analysis also suggested that So1P and Sa were able to indicate cardiovascular complications in diabetic patients. Pre-DM and diabetes were significantly associated with decreased So1P, SM, Sa and So, compared with the healthy controls. So1P was correlated with the progression of T2DM, and was a predictor of an elevated risk of cardiovascular complications among T2DM patients, along with Sa. The present study was registered with ClinicalTrials.gov (no. NCT02826759; April 2016).