Background: Obesity is characterized by increased oxidative stress, which, in a vicious circle, promotes chronic low-grade inflammation. Melatonin, a well-documented antioxidant, might be useful as a supplement to enhance the cardiometabolic benefits of any body weight reduction program (BWRP). Objectives/Methods: The present study aimed to evaluate the post-exercise oxidative stress and inflammation in a group of subjects with obesity treated with melatonin (2 mg/die) or placebo, undergoing a 2-week BWRP, with the administration of a single bout of acute exercise at the start and the end of the protocol (G1–G15). Results: Eighteen adults with obesity were enrolled and distributed to the two arms of the study: the melatonin group (F/M: 7/2; age: 27.8 ± 5.6 years; body mass index [BMI]: 43.0 ± 4.9 kg/m²) and the placebo group (F/M: 6/3; age: 28.8 ± 5.0 years; BMI: 42.8 ± 4.0 kg/m²). BWRP induced a decrease in BMI and waist circumference (WC) in both groups; plasma glucose, blood glycated hemoglobin (HbA_1c), and neutrophil to lymphocyte ratio (NLR) were reduced only in the placebo group. Importantly, plasma biological antioxidant potential (BAP) increased throughout BWRP. Paradoxically, melatonin enhanced post-exercise production of plasma derivatives of reactive oxygen metabolites (d-ROMs) and erythrocytic glutathionyl-Hb (HbSSG) (at G1 and G15). Finally, differently from the placebo group, melatonin-treated subjects did not exhibit the BWRP-induced decrease in plasma levels of interleukin-6 (IL-6), before and after exercise, at the end of two weeks (G15). Conclusions: Melatonin is presumably an antioxidant with “conditional” prooxidant actions. The use of melatonin as a supplement in subjects with obesity might be deleterious due to the abolishment of BWRP-induced cardiometabolic benefits.

Epstein–Barr virus (EBV) is causally associated with various malignancies and autoimmune diseases. It establishes a lifelong latent infection in host B-lymphocytes, and can strategically manipulate host cell metabolism and cell-to-cell communication via extracellular particles (EPs). While EBV-induced changes in fatty acid and mevalonate pathways are documented, the role of the sphingolipid network in this process remains poorly understood. In this study, we characterized both the EP and the cellular sphingolipid signatures of three EBV-infected (EBV+) lymphoblastoid cell lines compared to three EBV-negative (EBV−) counterparts. Lipidomic analysis revealed a profound metabolic redirection in EBV+ cells, characterized by reduced ceramide and sphingomyelin levels, and a significant upregulation of glycosphingolipids (GSLs), particularly hexosylceramide and globotrialosylceramide. Furthermore, EBV+ cells released larger, more heterogeneous EPs that are significantly enriched in GSLs and in the viral non-coding RNA EBER1. Our findings suggest that EBV-induced reshaping of sphingolipid metabolism correlates with altered physical properties of the secretome, potentially contributing to viral pathogenesis and microenvironmental manipulation.

Sphingolipid glycosylation is an enzymatic process that does not follow the pattern of nonenzymatic hemoglobin glycosylation. Unexpectedly, hexosyl- and lactosylceramides decreased in impaired fasting glucose and diabetes, with and without obesity. On the other hand, dihydroceramides increased in overweight/obesity with prediabetes/diabetes. The circulating sphingolipidome is differentially regulated in humans according to sex, glucose, and BMI.