Sphingomyelin profiling in patients with diabetes could be potentially useful as differential diagnostics biomarker: A pilot study

Purpose: Autoimmune diabetes (AD) in adults includes both the classical form of type 1 diabetes mellitus (T1DM) and latent autoimmune diabetes in adults (LADA). LADA shares clinical and metabolic features with type 1 and type 2 diabetes mellitus (T2DM). Ceramide (Cer) levels negatively correlate with insulin sensitivity in humans and animal models. However, only a few studies have focused on other sphingolipids, including sphingomyelin (SM). Therefore, we determined sphingolipids in patients with newly diagnosed diabetes as possible diagnostic biomarkers.Materials and methods: We evaluated sphingolipids in a cohort of 59 adults with newly diagnosed diabetes without prior hypoglycemic pharmacotherapy to distinguish diabetes mellitus types and for precise LADA definition. All patients with newly diagnosed diabetes were tested for the concentrations of individual Cer and SM species by gas-liquid chromatography. The study included healthy controls and patients with T1DM, T2DM and LADA.Results: SM species were significantly altered in patients with newly diagnosed diabetes compared to healthy controls. SM-C16:0, C16:1,-C18:0,-C18:1,-C18:2,-C18:3,-C20:4, and-C22:6 species were found to be signifi-cantly elevated in LADA patients. In contrast, significant differences were observed for Cer species with saturated acyl chains, especially Cer-C14:0,-C16:0,-C18:0 (AD and T2DM),-C22:0, and-C24:0 (T1DM). Following ROC analysis, SM-C16:0, and particularly-C18:1, and-C20:4 may be supportive diagnostic markers for LADA. Conclusion: SM profiling in patients with newly diagnosed diabetes could be potentially helpful for differential diagnosis of LADA, T1DM, and T2DM in more challenging cases.