Plasma ceramides as biomarkers for microvascular disease and clinical outcomes in diabetes and myocardial infarction.

BACKGROUND: Ceramides have recently been identified as novel biomarkers associated with diabetes mellitus (DM) and major adverse cardiac and cerebrovascular events (MACCE). This study aims to explore their utility in diagnosing microvascular disease. METHODS: This study prospectively enrolled 309 patients from 2018 to 2020 into three groups: healthy controls (Group 1, N = 51), DM patients without acute myocardial infarction (AMI) (Group 2, N = 150), and DM patients with AMI (Group 3, N = 108). We assessed outcomes using stress perfusion cardiac magnetic resonance (CMR) imaging for coronary microvascular disease (CMD) (Outcome 1), retinography for retinal microvascular disease (RMD) (Outcome 2), both CMD and RMD (Outcome 3), and absence of microvascular disease (w/o MD) (outcome 4). We evaluated the classification performance of ceramides using receiver operating characteristic (ROC) analysis and multiple logistic regression. 11-ceramide panel previously identified by our research group as related to macrovascular disease were used. RESULTS: Average glycated hemoglobin (HbA1c) values were 5.1% in Group 1, 8.3% in Group 2, and 7.6% in Group 3. Within the cohort, CMD was present in 59.5% of patients, RMD in 25.8%, both CMD and RMD in 18.8%, and w/o MD in 38.5%. The AUC values for the reference ceramide ratios were as follows: CMD at 0.66 (p = 0.012), RMD at 0.61 (p = 0.248), CMD & RMD at 0.64 (p = 0.282), and w/o MD at 0.67 (p = 0.010). In contrast, the AUC values using 11-ceramide panel showed significant improvement in the outcomes prediction: CMD at 0.81 (p = 0.001), RMD at 0.73 (p = 0.010), CMD & RMD at 0.73 (p = 0.04), and w/o MD at 0.83 (p = 0.010). Additionally, the plasma concentration of C14.0 was notably higher in the w/o MD group (p < 0.001). CONCLUSIONS: Plasma ceramides serve as potential predictors for health status and microvascular disease phenotypes in diabetic patients.

Nutrients, Physical Activity, and Mitochondrial Dysfunction in the Setting of Metabolic Syndrome.

Metabolic syndrome (MetS) is a cluster of metabolic risk factors for diabetes, coronary heart disease, non-alcoholic fatty liver disease, and some tumors. It includes insulin resistance, visceral adiposity, hypertension, and dyslipidemia. MetS is primarily linked to lipotoxicity, with ectopic fat deposition from fat storage exhaustion, more than obesity per se. Excessive intake of long-chain saturated fatty acid and sugar closely relates to lipotoxicity and MetS through several pathways, including toll-like receptor 4 activation, peroxisome proliferator-activated receptor-gamma regulation (PPARγ), sphingolipids remodeling, and protein kinase C activation. These mechanisms prompt mitochondrial dysfunction, which plays a key role in disrupting the metabolism of fatty acids and proteins and in developing insulin resistance. By contrast, the intake of monounsaturated, polyunsaturated, and medium-chain saturated (low-dose) fatty acids, as well as plant-based proteins and whey protein, favors an improvement in sphingolipid composition and metabolic profile. Along with dietary modification, regular exercises including aerobic, resistance, or combined training can target sphingolipid metabolism and improve mitochondrial function and MetS components. This review aimed to summarize the main dietary and biochemical aspects related to the physiopathology of MetS and its implications for mitochondrial machinery while discussing the potential role of diet and exercise in counteracting this complex clustering of metabolic dysfunctions.

Contribution of ceramides metabolism in psychiatric disorders.

Psychiatric disorders affect 970 million people worldwide, representing a significant source of disability. Although the underlying neurobiological traits for these disorders are not fully understood, a complex interplay between psychological, environmental, and biological factors contributes to their outcomes. Recent advances in lipidomic analysis and artificial intelligence algorithms have improved the identification of selective lipid species modulating the susceptibility to mental disorders. Sphingolipids (SLs) and ceramides-related SLs are among the most abundant lipids species in the brain that support major key pathways during neurodevelopment and brain plasticity. High levels of ceramides in plasma and brain contribute to psychiatric illness susceptibility in humans and animal models. However, the neuropathological mechanism regarding the involvement of ceramides in these disorders remain inconclusive. The brain is highly susceptible to nutritional insults, which could lead to functional impairment and influence the development and progression of psychiatric disorders. While the brain relies on glucose metabolism to support its physiological needs, a selective nutrient formula appears to have greater effects on brain health than others. For instance, consumption of high-energy diets is associated with brain anatomical, physiological, and metabolic changes, including ceramides metabolism. Herein, we will address the contribution of ceramides metabolism as a modulator of major psychiatric disorders such as depression, anxiety, bipolar disorder, schizophrenia, and attention deficit-hyperactivity disorder. We will also describe molecular and cellular targets of ceramides metabolism assisting the maintenance and progression of psychiatric disorders and their modulation by dietary formulas as non-pharmacologic treatments.

Effect of the CER[NP]:CER[AP] a ratio on the structure of a stratum corneum model lipid matrix - a molecular dynamics study.

In some dermal diseases with evident skin dehydration and desquamation, the natural ratio of CER[NP]:CER[AP] is altered in the extracellular matrix of the stratum corneum by increasing the concentration of CER[AP]. The extracellular matrix of the stratum corneum is composed of several stacked lipid bilayers. Molecular dynamics simulations were used to investigate the molecular nanostructure of CER[NP], CER[AP], cholesterol and lignoceric acid models of the extracellular matrix of the stratum corneum with a nativelike CER[NP]:CER[AP] 2:1 ratio and a CER[NP]:CER[AP] ratio of 1:2. Despite the very minor chemical difference between CER[NP] and CER[AP], which is only a single OH group, it was possible to observe differences between the structural influence of the two ceramides. In the models with 1:2 ratio, the higher CER[AP] content leads to a larger inclination of the acyl chains and a smaller overlap in the lamellar midplane, with a small increase of the repeat distance compared to the model with higher CER[NP] concentration. Because CER[AP] forms more H-bonds than CER[NP], the total number of hydrogen bonds in the headgroup region is larger in the models with higher CER[AP] concentration, reducing the mobility of the lipids towards the centre of the bilayer and resulting in less overlap and increased tilt angles.

Serum sphingolipid profiling as a novel biomarker for metabolic syndrome characterization.

Background: Sphingolipids are components of cell membrane structure, but also circulate in serum and are essential mediators of many cellular functions. While ceramides have been proposed previously as a useful biomarker for cardiometabolic disease, the involvement of other sphingolipids is still controversial. The aim of this study was to investigate the cross-sectional association between blood sphingolipidomic profiles and metabolic syndrome (MetS) as well as other atherosclerotic risk factors in a large population-based study in the U.S. Methods: Clinical data and serum sphingolipidomic profiling from 2,063 subjects who participated in the biomarker project of the Midlife in the United States (MIDUS) study were used. Results: Consistent with previous reports, we found a positive association between most ceramide levels and obesity, atherogenic dyslipidemia, impaired glucose metabolism, and MetS prevalence. In contrast, most simple ß-glycosphingolipids (i.e., hexosylceramides and lactosylceramides) were inversely associated with dysmetabolic biomarkers. However, this latter sphingolipid class showed a positive link with inflammatory and vascular damage-associated biomarkers in subjects with MetS. Through metabolic network analysis, we found that the relationship between ceramides and simple ß-glycosphingolipids differed significantly not only according to MetS status, but also with respect to the participants' C-reactive protein levels. Conclusion: Our findings suggest that a comprehensive sphingolipid profile is more informative about MetS than ceramides alone, and it may reveal new insights into the pathophysiology and further diabetic vs. cardiovascular risk in patients with MetS.

Infusion of C20:0 ceramide into ventral hippocampus triggers anhedonia-like behavior in female and male rats.

Increased long-chain C20:0 ceramides have been found in the serum of patients with depression. Moreover, ceramides are linked with increased microglia reactivity and inflammatory cytokine production, which are associated with depression. Since ceramides can readily cross the blood brain barrier, peripheral C20:0 ceramides could enter the brain, activate microglia, and induce depressive-like behavior. In this study, we determined whether localized infusion of C20:0 ceramides into the ventral hippocampus (VH) of rats is sufficient to activate microglia and induce depressive-like behaviors. Adult male and female rats received infusions of C20:0 ceramides or vehicle solution every other day for 2 weeks. After the third infusion, C20:0-infused animals showed reduced sucrose preference suggesting anhedonia-like behavior. In contrast, infusions of C20:0 ceramides did not affect immobility in the forced swim test or sucrose grooming suggesting that the behavioral effects of ceramides are task dependent. Furthermore, C20:0-infusions did not increase Iba-1 + microglia or inflammatory markers in the VH suggesting that localized increases in C20:0 ceramides in the VH are sufficient to induce anhedonia-like behavior without microglia activation.

High-Fat Diet and Short-Term Unpredictable Stress Increase Long-Chain Ceramides Without Enhancing Behavioral Despair.

Clinical and preclinical studies suggest that increases in long-chain ceramides in blood may contribute to the development of depressive-like behavior. However, which factors contribute to these increases and whether the increases are sufficient to induce depressive-like behaviors is unclear. To begin to address this issue, we examined the effects of high fat diet (HFD) and short-term unpredictable (STU) stress on long-chain ceramides in the serum of male and female rats. We found that brief exposure to HFD or unpredictable stress was sufficient to induce selective increases in the serum concentrations of long-chain ceramides, associated with depression in people. Furthermore, combined exposure to HFD and unpredictable stress caused a synergistic increase in C16:0, C16:1, and C18:0 ceramides in both sexes and C18:1 and C24:1 in males. However, the increased peripheral long-chain ceramides were not associated with increases in depressive-like behaviors suggesting that increases in serum long-chain ceramides may not be associated with the development of depressive-like behaviors in rodents.

Ceramidas Plasmáticas na Estratificação de Risco das Doenças Cardiovasculares / Plasma Ceramides in Cardiovascular Disease Risk Stratification

Resumo A produção de ceramida ocorre em todo o corpo e desempenha um papel importante na manutenção da fisiologia normal. No entanto, os níveis de ceramidas são alterados em estados de doença, principalmente durante o desenvolvimento de diabetes e dislipidemia. A produção de ceramidas também está associada à instabilidade das placas ateroscleróticas. Estudos recentes revelam que pacientes com doença arterial coronariana instável apresentam níveis plasmáticos aumentados de ceramidas (principalmente C16, C18 e C24:1). Atualmente, são consideradas biomarcadores emergentes nas doenças cardiovasculares, sendo utilizadas na predição de instabilidade da placa aterosclerótica e eventos cardiovasculares adversos de forma independente aos fatores de risco tradicionais. Com o objetivo de descrever e discutir o papel das ceramidas na estratificação das doenças cardiovasculares, o desenvolvimento desta revisão narrativa contextualiza a importância desse biomarcador no cenário atual da cardiologia.

Abstract Ceramide production takes place throughout the body and plays a key role in the maintenance of normal physiology. However, ceramide levels are altered during disease states, particularly considering the development of diabetes and dyslipidemia. Ceramide production is also associated with atherosclerotic plaque instability. Recent studies revealed that patients with unstable coronary artery disease (CAD) presented increased plasma ceramide levels (especially C16, C18, and C24:1). These molecules are currently considered emerging biomarkers of cardiovascular diseases (CVD), being used for predicting atherosclerotic plaque instability and adverse cardiovascular events independently from traditional risk factors. With the aim of describing and discussing the role of ceramides in the stratification of cardiovascular diseases, this narrative review contextualizes the importance of this biomarker in the present cardiology scenario.

Sex differences in the association of sphingolipids with age in Dutch and South-Asian Surinamese living in Amsterdam, the Netherlands.

BACKGROUND: Men have a higher risk for cardiovascular disease (CVD) early in life, while women have a higher risk later in life. The sex-related differences in CVD risk, especially by age, could be related to sphingolipid metabolism. We compared plasma sphingolipid concentrations and its increase by age in men and women. METHODS: Plasma concentrations of 13 types of sphingolipids were measured by liquid chromatography-tandem mass spectrometry in a random subsample of 328 men and 372 women of Dutch and South-Asian Surinamese ethnic origin, participating in the HELIUS study. Sphingolipid concentrations were compared between men and women by age group (18-39, 40-55, and 56-70 years). Multiple linear regression was used to determine sex differences in age trends in sphingolipids stratified by ethnicity. Analyses were performed without adjustment and adjusted for body mass index (BMI) and waist circumference. RESULTS: At age 18-39 years, sphingolipid concentrations were lower in women than those in men, but at age 56-70 years this was reversed. At higher age, women showed higher concentrations than men. In line, we observed a more rapid increase of sphingolipid concentrations by age in women than in men. The observed sex differences were not explained by BMI or waist circumference. Patterns of sex differences were similar across ethnic groups, although the strength of associations differed. CONCLUSIONS: Mean sphingolipid concentrations increase more rapidly with age in women than in men. Therefore, plasma lipid concentrations of sphingolipids, although lower in women than in men at younger age, are higher in women than in men at older age.

Sphingolipid Profiling: A Promising Tool for Stratifying the Metabolic Syndrome-Associated Risk.

Metabolic syndrome (MetS) is a multicomponent risk condition that reflects the clustering of individual cardiometabolic risk factors related to abdominal obesity and insulin resistance. MetS increases the risk for cardiovascular diseases (CVD) and type 2 diabetes mellitus (T2DM). However, there still is not total clinical consensus about the definition of MetS, and its pathophysiology seems to be heterogeneous. Moreover, it remains unclear whether MetS is a single syndrome or a set of diverse clinical conditions conferring different metabolic and cardiovascular risks. Indeed, traditional biomarkers alone do not explain well such heterogeneity or the risk of associated diseases. There is thus a need to identify additional biomarkers that may contribute to a better understanding of MetS, along with more accurate prognosis of its various chronic disease risks. To fulfill this need, omics technologies may offer new insights into associations between sphingolipids and cardiometabolic diseases. Particularly, ceramides -the most widely studied sphingolipid class- have been shown to play a causative role in both T2DM and CVD. However, the involvement of simple glycosphingolipids remains controversial. This review focuses on the current understanding of MetS heterogeneity and discuss recent findings to address how sphingolipid profiling can be applied to better characterize MetS-associated risks.

Alteration of Sphingolipids in Biofluids: Implications for Neurodegenerative Diseases.

Sphingolipids (SL) modulate several cellular processes including cell death, proliferation and autophagy. The conversion of sphingomyelin (SM) to ceramide and the balance between ceramide and sphingosine-1-phosphate (S1P), also known as the SL rheostat, have been associated with oxidative stress and neurodegeneration. Research in the last decade has focused on the possibility of targeting the SL metabolism as a therapeutic option; and SL levels in biofluids, including serum, plasma, and cerebrospinal fluid (CSF), have been measured in several neurodegenerative diseases with the aim of finding a diagnostic or prognostic marker. Previous reviews focused on results from diseases such as Alzheimer's Disease (AD), evaluated total SL or species levels in human biofluids, post-mortem tissues and/or animal models. However, a comprehensive review of SL alterations comparing results from several neurodegenerative diseases is lacking. The present work compiles data from circulating sphingolipidomic studies and attempts to elucidate a possible connection between certain SL species and neurodegeneration processes. Furthermore, the effects of ceramide species according to their acyl-chain length in cellular pathways such as apoptosis and proliferation are discussed in order to understand the impact of the level alteration in specific species. Finally, enzymatic regulations and the possible influence of insulin resistance in the level alteration of SL are evaluated.

Plasma Ceramides as Prognostic Biomarkers and Their Arterial and Myocardial Tissue Correlates in Acute Myocardial Infarction.

We identified a plasma signature of 11 C14 to C26 ceramides and 1 C16 dihydroceramide predictive of major adverse cardiovascular events in patients with acute myocardial infarction (AMI). Among patients undergoing coronary artery bypass surgery, those with recent AMI, compared with those without recent AMI, showed a significant increase in 5 of the signature's 12 ceramides in plasma but not simultaneously-biopsied aortic tissue. In contrast, a rat AMI model, compared with sham control, showed a significant increase in myocardial concentrations of all 12 ceramides and up-regulation of 3 ceramide-producing enzymes, suggesting ischemic myocardium as a possible source of this ceramide signature.

Ceramide Metabolism Balance, a Multifaceted Factor in Critical Steps of Breast Cancer Development.

Ceramides are key lipids in energetic-metabolic pathways and signaling cascades, modulating critical physiological functions in cells. While synthesis of ceramides is performed in endoplasmic reticulum (ER), which is altered under overnutrition conditions, proteins associated with ceramide metabolism are located on membrane arrangement of mitochondria and ER (MAMs). However, ceramide accumulation in meta-inflammation, condition that associates obesity with a chronic low-grade inflammatory state, favors the deregulation of pathways such as insulin signaling, and induces structural rearrangements on mitochondrial membrane, modifying its permeability and altering the flux of ions and other molecules. Considering the wide biological processes in which sphingolipids are implicated, they have been associated with diseases that present abnormalities in their energetic metabolism, such as breast cancer. In this sense, sphingolipids could modulate various cell features, such as growth, proliferation, survival, senescence, and apoptosis in cancer progression; moreover, ceramide metabolism is associated to chemotherapy resistance, and regulation of metastasis. Cell⁻cell communication mediated by exosomes and lipoproteins has become relevant in the transport of several sphingolipids. Therefore, in this work we performed a comprehensive analysis of the state of the art about the multifaceted roles of ceramides, specifically the deregulation of ceramide metabolism pathways, being a key factor that could modulate neoplastic processes development. Under specific conditions, sphingolipids perform important functions in several cellular processes, and depending on the preponderant species and cellular and/or tissue status can inhibit or promote the development of metabolic and potentially breast cancer disease.

Lipid Biochemical and Biophysical Changes in Rat Spermatozoa During Isolation and Functional Activation In Vitro.

In spermatozoa isolated from rat epididymis, lipids are differentially modified after in vitro induction of capacitation (Cap) and the acrosomal reaction (AR). This study uses Laurdan fluorescence generalized polarization values (GPv) to evaluate the effect of lipid changes occurring after isolation and functional activation on sperm membrane biophysical properties. In gametes isolated in the presence of a divalent cation chelator, no lipid changes occurred and the GPv were the lowest recorded, indicating maximal membrane lipid mobility. In sperm isolated as rapidly and gently as possible in the absence of chelator, part of the sphingomyelins (SM) were converted into ceramides (Cer), giving rise to higher GPv. In samples incubated as controls for Cap and AR, unchanged cholesterol and reduced glycerophospholipid levels were accompanied by the accumulation of free fatty acids (FFA), leading to even higher GPv. After completion of Cap, the GPv returned to lower levels as a result of the spermatozoa losing part of their cholesterol and FFA. Cap samples became relatively enriched in polyunsaturated fatty acids-containing plasmalogens because hydrolysis affected phosphatidyl rather than plasmenyl glycerophospholipid subclasses. The highest Cer:SM ratio and the highest GPv were found after completion of AR induced by A23187. The degree of SM → Cer conversion among the samples, including controls, correlated with the extent of AR. FFA and Cer augmented GPv when added to liposomes prepared from the membrane lipid of intact sperm. Our results underscore the importance of hydrolytic changes that affect sperm lipids, especially the decisive lipid SM and Cer pair, not only after inducing sperm functional changes such as Cap and AR, but also under control conditions.

Low serum sphingolipids in children with attention deficit-hyperactivity disorder.

BACKGROUND: Attention deficit-hyperactivity disorder (ADHD) is the most prevalent neuropsychiatric condition in childhood. ADHD is a multifactorial trait with a strong genetic component. One neurodevelopmental hypothesis is that ADHD is associated with a lag in brain maturation. Sphingolipids are essential for brain development and neuronal functioning, but their role in ADHD pathogenesis is unexplored. We hypothesized that serum sphingolipid levels distinguish ADHD patients from unaffected subjects. METHODS: We characterized serum sphingolipid profiles of ADHD patients and two control groups: non-affected relatives and non-affected subjects without a family history of ADHD. Sphingolipids were measured by LC-MS/MS in 77 participants (28 ADHD patients, 28 related controls, and 21 unrelated controls). ADHD diagnosis was based on the Diagnostic and Statistical Manual of Mental Disorders (DSM IV-TR). Diagnostic criteria were assessed by two independent observers. Groups were compared by parametrical statistics. RESULTS: Serum sphingomyelins C16:0, C18:0, C18:1, C24:1, ceramide C24:0, and deoxy-ceramide C24:1 were significantly decreased in ADHD patients at 20-30% relative reductions. In our sample, decreased serum sphingomyelin levels distinguished ADHD patients with 79% sensitivity and 78% specificity. CONCLUSIONS: Our results showed lower levels of all major serum sphingomyelins in ADHD. These findings may reflect brain maturation and affect neuro-functional pathways characteristic for ADHD.

Ceramides and terpenoids from Russula austrodelica Singer / Ceramidas y terpenoides desde Russula austrodelica Singer

A mixture of ceramides and known terpenes, was obtained from the fruiting bodies of Russula austrodelica. The structures were determined from chemical and spectroscopic evidence. R. austrodelica is a mycorrhizal fungus that grow in the Nothophagus forests of southern Chile. This is the first report of the isolation of ceramides in Chilean mushrooms.

Una mezcla de ceramidas y de terpenos conocidos, se obtuvo de los cuerpos fructíferos de Russula austrodelica. Las estructuras fueron determinadas a partir de evidencias químicas y espectroscópicas. R. austrodelica es un hongo micorrícico que crecen en los bosques de Nothophagus del sur de Chile. Este es el primer informe del aislamiento de ceramidas en hongos chilenos.