Background and Aims: We previously identified subsets of patients with NAFLD with different metabolic phenotypes. Here we align metabolomic signatures with cardiovascular disease (CVD) and genetic risk factors. Approach and Results: We analyzed serum metabolome from 1154 individuals with biopsy‐proven NAFLD, and from four mouse models of NAFLD with impaired VLDL‐triglyceride (TG) secretion, and one with normal VLDL‐TG secretion. We identified three metabolic subtypes: A (47%), B (27%), and C (26%). Subtype A phenocopied the metabolome of mice with impaired VLDL‐TG secretion; subtype C phenocopied the metabolome of mice with normal VLDL‐TG; and subtype B showed an intermediate signature. The percent of patients with NASH and fibrosis was comparable among subtypes, although subtypes B and C exhibited higher liver enzymes. Serum VLDL‐TG levels and secretion rate were lower among subtype A compared with subtypes B and C. Subtype A VLDL‐TG and VLDL–apolipoprotein B concentrations were independent of steatosis, whereas subtypes B and C showed an association with these parameters. Serum TG, cholesterol, VLDL, small dense LDL_5,6, and remnant lipoprotein cholesterol were lower among subtype A compared with subtypes B and C. The 10‐year high risk of CVD, measured with the Framingham risk score, and the frequency of patatin‐like phospholipase domain‐containing protein 3 NAFLD risk allele were lower in subtype A. Conclusions: Metabolomic signatures identify three NAFLD subgroups, independent of histological disease severity. These signatures align with known CVD and genetic risk factors, with subtype A exhibiting a lower CVD risk profile. This may account for the variation in hepatic versus cardiovascular outcomes, offering clinically relevant risk stratification.

Sphingolipids consist of a sphingoid base N-linked to a fatty acyl chain. Among them, sphingomyelins (SM) are major components of mammalian cells, while ceramide (Cer) plays an important role as a lipid second messenger. We have performed a quantitative lipidomic study of Cer and SM species in different mammalian tissues (adipose tissue, liver, brain and blood serum of human, mice, rat and dog), as well as in cell cultures of mammalian origin (primary hepatocytes, immortalized MDCK cells, mice melanoma b16 cells, and mice primary CD4 + T lymphocytes) using an ultra-high performance liquid chromatography coupled to time-of-flight mass spectrometry (UHPLC-ToF-MS)-based platform. The data have been compared with published, in general semi-quantitative, results from 20 other samples, with good agreement. The sphingoid base was predominantly d18-1 sphingosine (2-amino-4-octadecene-1,3-diol) in all cases. The fatty acid composition of SM was clearly different from that of Cer. In virtually all samples the most abundant Cer species were those containing C24:0 and C24:1 in their N-acyl chains, while the main species contained in SM was C16:0. Brain was the most divergent tissue, in which Cer and SM C18:0 were very abundant.

Inborn errors of metabolism (IEMs) are rare diseases produced by the accumulation of abnormal amounts of metabolites, toxic to the newborn. When not detected on time, they can lead to irreversible physiological and psychological sequels or even demise. Metabolomics has emerged as an efficient and powerful tool for IEM detection in newborns, children, and adults with late onset. In here, we screened urine samples from a large set of neonates (470 individuals) from a homogeneous population (Basque Country), for the identification of congenital metabolic diseases using NMR spectroscopy. Absolute quantification allowed to derive a probability function for up to 66 metabolites that adequately describes their normal concentration ranges in newborns from the Basque Country. The absence of another 84 metabolites, considered abnormal, was routinely verified in the healthy newborn population and confirmed for all but 2 samples, of which one showed toxic concentrations of metabolites associated to ketosis and the other one a high trimethylamine concentration that strongly suggested an episode of trimethylaminuria. Thus, a non-invasive and readily accessible urine sample contains enough information to assess the potential existence of a substantial number (>70) of IEMs in newborns, using a single, automated and standardized ¹H- NMR-based analysis.

Summary: Background: Sirtuin 1 (Sirt1) is suppressed in non‐alcoholic fatty liver disease (NAFLD), while its’ stimulation or overexpression results in reduced disease severity in pre‐clinical NAFLD models. Leucine allosterically activates Sirt1 and synergise with other Sirt/AMPK/NO pathway activators. We developed a triple combination of leucine, metformin and sildenafil (NS‐0200), which was effective in a mouse model of non‐alcoholic steatohepatitis (NASH).Aim: To report the results from a Phase 2, randomised clinical trial of of NS‐0200 in 91 subjects with NAFLD (liver fat ≥15% by magnetic resonance imaging‐proton‐density fat fraction (MRI‐PDFF)).Methods: Subjects were randomised to placebo, low‐dose (1.1 g leucine/0.5 g metformin/0.5 mg sildenafil) or high‐dose NS‐0200 (1.1 g leucine/0.5 g metformin/1.0 mg sildenafil) b.d. for 16 weeks; change in hepatic fat was assessed via MRI‐PDFF, and lipid metabolism was assessed via changes in the lipidomic signature. Seventy subjects completed the trial and met a priori compliance criteria. Analyses were conducted on the full cohort and on those with alanine aminotransferase (ALT) values above median (50 U/L; n = 35).Results: In the full cohort, active treatments did not separate from placebo. High dose NS‐0200 reduced hepatic fat by 15.7% (relative change from baseline) in the high ALT group (P < 0.005) while low dose NS‐0200 and placebo did not significantly change hepatic fat. Lipidomic analysis showed dose‐responsive treatment effects in both overall and high ALT cohorts, with significant decreases in metabolically active lipids and up‐regulation of fatty acid oxidation.Conclusion: These data support further evaluation of high‐dose NS‐0200 for treating NASH, especially in those with elevated ALT (NCT 02546609).