The associations between individual plasma SFAs, serine palmitoyl-transferase long-chain base subunit 3 gene rs680379 polymorphism, and type 2 diabetes among Chinese adults

Metabolic profiling reveals altered amino acid and fatty acid metabolism in children with Williams Syndrome

Williams Syndrome (WS) is a rare neurodevelopmental disorder with a prevalence of 1 in 7500 to 1 in 20,000 individuals, caused by a microdeletion in chromosome 7q11.23. Despite its distinctive clinical features, the underlying metabolic alterations remain largely unexplored. This study employs targeted metabolomics to investigate the metabolic characteristics of children with WS. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), we identified significant dysregulation of 15 metabolites, with 11 upregulated and 4 downregulated. Notably, amino acids such as alanine, proline, and arginine were significantly elevated. Fatty acid metabolism showed pronounced upregulation of long-chain saturated fatty acids (C18:0, C20:0, C22:0, C24:0, C26:0, and C28:0) and downregulation of long-chain unsaturated fatty acids (C18:2 LA, C22:6 DHA, C16:1 PLA, and t-C18:1 EA), except for upregulated nervonic acid (C24:1) and arachidonic acid (C20:4). Metabolic pathway analysis highlighted disruptions in arginine synthesis, arginine/proline metabolism, alanine, aspartate and glutamate metabolism, biosynthesis of unsaturated fatty acids, linoleic acid metabolism, and arachidonic acid metabolism. This study provides the first comprehensive analysis of amino acid and fatty acid metabolism in children with WS, offering insights into the disorder's complex metabolic landscape. Further validation in larger cohorts is essential to confirm these findings and their potential as biomarkers and therapeutic targets.

SPTLC3 regulates plasma membrane sphingolipid composition to facilitate hepatic gluconeogenesis

SPTLC3, an inducible subunit of the serine palmitoyltransferase (SPT) complex, causes production of alternative sphingoid bases, including a 16-carbon dihydrosphingosine, whose biological function is only beginning to emerge. High-fat feeding induced SPTLC3 in the liver, prompting us to produce a liver-specific knockout mouse line. Following high-fat feeding, knockout mice showed decreased fasting blood glucose, and knockout primary hepatocytes showed suppressed glucose production, a core function of hepatocytes. Stable isotope tracing revealed suppression of the gluconeogenic pathway, finding that SPTLC3 was required to maintain expression of key gluconeogenic genes via adenylate cyclase/cyclic AMP (cAMP)/cAMP response element binding protein (CREB) signaling. Additionally, by employing a combination of a recently developed lipidomics methodology, exogenous C14/C16 fatty acid treatment, and in situ adenylate cyclase activity, we implicated a functional interaction between sphingomyelin with a d16 backbone and adenylate cyclase at the plasma membrane. This work pinpoints a specific sphingolipid-protein functional interaction with broad implications for understanding sphingolipid signaling and metabolic disease.

Emerging Roles for Sphingolipids in Cardiometabolic Disease: A Rational Therapeutic Target?

Cardiovascular disease is a leading cause of morbidity and mortality. New research elucidates increasingly complex relationships between cardiac and metabolic health, giving rise to new possible therapeutic targets. Sphingolipids are a heterogeneous class of bioactive lipids with critical roles in normal human physiology. They have also been shown to play both protective and deleterious roles in the pathogenesis of cardiovascular disease. Ceramides are implicated in dysregulating insulin signalling, vascular endothelial function, inflammation, oxidative stress, and lipoprotein aggregation, thereby promoting atherosclerosis and vascular disease. Ceramides also advance myocardial disease by enhancing pathological cardiac remodelling and cardiomyocyte death. Glucosylceramides similarly contribute to insulin resistance and vascular inflammation, thus playing a role in atherogenesis and cardiometabolic dysfunction. Sphingosing-1-phosphate, on the other hand, may ameliorate some of the pathological functions of ceramide by protecting endothelial barrier integrity and promoting cell survival. Sphingosine-1-phosphate is, however, implicated in the development of cardiac fibrosis. This review will explore the roles of sphingolipids in vascular, cardiac, and metabolic pathologies and will evaluate the therapeutic potential in targeting sphingolipids with the aim of prevention and reversal of cardiovascular disease in order to improve long-term cardiovascular outcomes.

Cow's Milk Bioactive Molecules in the Regulation of Glucose Homeostasis in Human and Animal Studies

Obesity disrupts glucose metabolism, leading to insulin resistance (IR) and cardiometabolic diseases. Consumption of cow's milk and other dairy products may influence glucose metabolism. Within the complex matrix of cow's milk, various carbohydrates, lipids, and peptides act as bioactive molecules to alter human metabolism. Here, we summarize data from human studies and rodent experiments illustrating how these bioactive molecules regulate insulin and glucose homeostasis, supplemented with in vitro studies of the mechanisms behind their effects. Bioactive carbohydrates, including lactose, galactose, and oligosaccharides, generally reduce hyperglycemia, possibly by preventing gut microbiota dysbiosis. Milk-derived lipids of the milk fat globular membrane improve activation of insulin signaling pathways in animal trials but seem to have little impact on glycemia in human studies. However, other lipids produced by ruminants, including polar lipids, odd-chain, trans-, and branched-chain fatty acids, produce neutral or contradictory effects on glucose metabolism. Bioactive peptides derived from whey and casein may exert their effects both directly through their insulinotropic effects or renin-angiotensin-aldosterone system inhibition and indirectly by the regulation of incretin hormones. Overall, the results bolster many observational studies in humans and suggest that cow's milk intake reduces the risk of, and can perhaps be used in treating, metabolic disorders. However, the mechanisms of action for most bioactive compounds in milk are still largely undiscovered.

Circulating sphingolipids in heart failure

Lack of significant advancements in early detection and treatment of heart failure have precipitated the need for discovery of novel biomarkers and therapeutic targets. Over the past decade, circulating sphingolipids have elicited promising results as biomarkers that premonish adverse cardiac events. Additionally, compelling evidence directly ties sphingolipids to these events in patients with incident heart failure. This review aims to summarize the current literature on circulating sphingolipids in both human cohorts and animal models of heart failure. The goal is to provide direction and focus for future mechanistic studies in heart failure, as well as pave the way for the development of new sphingolipid biomarkers.

Fatty Acid Profile and Genetic Variants of Proteins Involved in Fatty Acid Metabolism Could Be Considered as Disease Predictor

Circulating fatty acids (FA) have an endogenous or exogenous origin and are metabolized under the effect of many enzymes. They play crucial roles in many mechanisms: cell signaling, modulation of gene expression, etc., which leads to the hypothesis that their perturbation could be the cause of disease development. FA in erythrocytes and plasma rather than dietary FA could be used as a biomarker for many diseases. Cardiovascular disease was associated with elevated trans FA and decreased DHA and EPA. Increased arachidonic acid and decreased Docosahexaenoic Acids (DHA) were associated with Alzheimer's disease. Low Arachidonic acid and DHA are associated with neonatal morbidities and mortality. Decreased saturated fatty acids (SFA), increased monounsaturated FA (MUFA) and polyunsaturated FA (PUFA) (C18:2 n-6 and C20:3 n-6) are associated with cancer. Additionally, genetic polymorphisms in genes coding for enzymes implicated in FA metabolism are associated with disease development. FA desaturase (FADS1 and FADS2) polymorphisms are associated with Alzheimer's disease, Acute Coronary Syndrome, Autism spectrum disorder and obesity. Polymorphisms in FA elongase (ELOVL2) are associated with Alzheimer's disease, Autism spectrum disorder and obesity. FA-binding protein polymorphism is associated with dyslipidemia, type 2 diabetes, metabolic syndrome, obesity, hypertension, non-alcoholic fatty liver disease, peripheral atherosclerosis combined with type 2 diabetes and polycystic ovary syndrome. Acetyl-coenzyme A carboxylase polymorphisms are associated with diabetes, obesity and diabetic nephropathy. FA profile and genetic variants of proteins implicated in FA metabolism could be considered as disease biomarkers and may help with the prevention and management of diseases.

Plasma Transthyretin Levels and Risk of Type 2 Diabetes Mellitus and Impaired Glucose Regulation in a Chinese Population

Plasma transthyretin may be engaged in glucose regulation. We aimed to investigate the association between plasma transthyretin levels and the risk of newly diagnosed T2DM and impaired glucose regulation (IGR) in a Chinese population. We conducted a case-control study including 1244 newly diagnosed T2DM patients, 837 newly diagnosed IGR patients, and 1244 individuals with normal glucose tolerance (NGT) matched by sex and age. Multivariate logistic regression analysis was utilized to estimate the independent association of plasma transthyretin concentrations with the risk of T2DM and IGR. Plasma transthyretin concentrations were significantly higher in T2DM and IGR patients compared with control subjects (p < 0.005). After multiple adjustment and comparison with the lowest quartile of plasma transthyretin concentrations, the odds ratios (95% confidence intervals) of T2DM and IGR in the highest quartile were 2.22 (1.66, 2.98) and 2.29 (1.72, 3.05), respectively. Plasma transthyretin concentrations also showed a great performance in predicting the risk of T2DM (AUC: 0.76). Moreover, a potential nonlinear trend was observed. Our results demonstrated that higher plasma transthyretin concentrations, especially more than 290 mg/L, were associated with an increased risk of T2DM and IGR. Further studies are warranted to confirm our findings and elucidate the potential mechanisms.

Very long-chain saturated fatty acids and diabetes and cardiovascular disease

PURPOSE OF REVIEW

In contrast to other saturated fatty acids, very long-chain saturated fatty acids (VLSFAs) have received limited attention The purpose of this review is to summarize the associations of VLSFAs, including arachidic acid, behenic acid, and lignoceric acid, with cardiovascular disease outcomes and type 2 diabetes; to discuss the findings implications; and to call for future studies of the VLSFAs.

RECENT FINDINGS

Increased levels of circulating VLSFAs have been found associated with lower risks of incident heart failure, atrial fibrillation, coronary heart disease, mortality, sudden cardiac arrest, type 2 diabetes, and with better aging. The VLSFA associations are paralleled by associations of plasma ceramide and sphingomyelin species carrying a VLSFA with lower risks of heart failure, atrial fibrillation, and mortality, suggesting VLSFAs affect the biological activity of ceramides and sphingomyelins thereby impacting health. For diabetes, there is no such parallel and the associations of VLSFAs with diabetes may be confounded or mediated by triglyceride and circulating palmitic acid, possible biomarkers of de novo lipogenesis.

SUMMARY

In many ways, the epidemiology has preceded our knowledge of VLSFAs biology. We hope this review will spur interest from the research community in further studying these potentially beneficial fatty acids.