Maternal diets affected ceramides and fatty acids in brain regions of neonatal rats with prenatal ethanol exposure

Objectives: Ceramide (Cer), known as apoptotic markers, increases with prenatal ethanol (EtOH) exposure, resulting in neuroapoptosis. Whether maternal nutrition can impact Cer concentrations in brain, via altering plasma and brain fatty acid compositions have not been examined. This study compared a standard chow with a formulated semi-purified energy dense (E-dense) diet on fatty acid composition, Cer concentrations, and apoptosis in plasma and brain regions (cortex, cerebellum, and hippocampus) of pups exposed to EtOH during gestation. Methods: Pregnant Sprague-Dawley rats were randomized into four groups: chow (n = 6), chow + EtOH (20% v/v) (n = 7), E-dense (n = 6), and E-dense + EtOH (n = 8). At postnatal day 7, representing the peak brain growth spurt in rats, lipids, and apoptosis were analyzed by gas chromatography and a fluorometric caspase-3 assay kit, respectively. Results: Maternal E-dense diet increased total fatty acid concentrations (p < 0.0001), including docosahexaenoic acid (DHA) (p < 0.0001) in plasma, whereas DHA concentrations were decreased in the cerebellum (p < 0.03) of pups than those from chow-fed dams. EtOH-induced Cer elevations in the hippocampus of pups born to dams fed chow were reduced by an E-dense diet (p < 0.02). No significant effects of maternal diet quality and EtOH were observed on caspase-3 activity. No significant correlations existed between plasma/brain fatty acids and Cer concentrations. Discussions: Maternal diet quality affected fatty acid compositions and Cer concentrations of pups with prenatal EtOH exposure, differently. Maternal nutrition has the potential to prevent or alleviate some of the adverse effects of prenatal EtOH exposure.

Sphingolipids in neurodegenerative diseases

Neurodegenerative Diseases (NDDs) are a group of disorders that cause progressive deficits of neuronal function. Recent evidence argues that sphingolipid metabolism is affected in a surprisingly broad set of NDDs. These include some lysosomal storage diseases (LSDs), hereditary sensory and autonomous neuropathy (HSAN), hereditary spastic paraplegia (HSP), infantile neuroaxonal dystrophy (INAD), Friedreich's ataxia (FRDA), as well as some forms of amyotrophic lateral sclerosis (ALS) and Parkinson's disease (PD). Many of these diseases have been modeled in Drosophila melanogaster and are associated with elevated levels of ceramides. Similar changes have also been reported in vertebrate cells and mouse models. Here, we summarize studies using fly models and/or patient samples which demonstrate the nature of the defects in sphingolipid metabolism, the organelles that are implicated, the cell types that are initially affected, and potential therapeutics for these diseases.

Tanacetum species: Bridging empirical knowledge, phytochemistry, nutritional value, health benefits and clinical evidence

Introduction: The Tanacetum genus consists of 160 accepted flowering species thriving throughout temperate regions, mainly in the Mediterranean Basin, Northern America, and southwestern and eastern Asia. Tanacetum species bear a long-standing record of use in the folk medicine of indigenous tribes and communities worldwide, along with multitudinous applications in traditional cuisines, cosmeceuticals, and agricultural fields. Methods: Up-to-date data related to traditional uses, phytochemistry, biological activities, toxicity and clinical trials of the genus Tanacetum were systematically reviewed from several online scientific engines, including PubMed, Web of Science, Scopus, SciFinder, Wiley Online, Science Direct, and Cochrane library. Results and discussion: Over the past three decades, 241 metabolites have been isolated from nearly twenty species, including phenolic acids, flavonoids, coumarins, fatty acids and alkanes, aldehydes, volatile compounds, and naphthoquinones. Some unique metabolites have also been identified, such as the ceramides tanacetamide (A-D) from T. artemisioides, pyrethrins from T. cinerariifolium, and sesquiterpene lactones from several species. However, these secondary metabolites are still poorly studied despite in vitro clues highlighting their colossal pharmacological properties, especially as hypotensive, neuroprotective, anticancer, and antimicrobial agents. Scientific studies have validated some traditional claims of the plant, such as antidiabetic, anticancer, anthelmintic, insecticide, antioxidant, and hepatoprotective activities, as well as against festering wounds, skin ulcers, urinary tract infections, and sexually transmitted diseases. Other ethnomedicinal uses for arthritis, gout, rheumatism, anemia, and as a litholytic, antivenom and diaphoretic have not yet been supported and would constitute the subject of further research.

The effect of PPAR isoform (de)activation on the lipid composition in full-thickness skin models

Human skin equivalents (HSEs) are 3D-cultured human skin models that mimic many aspects of native human skin (NHS). Although HSEs resemble NHS very closely, the barrier located in the stratum corneum (SC) is impaired. This is caused by an altered lipid composition in the SC of HSEs compared with NHS. One of the most pronounced changes in this lipid composition is a high level of monounsaturation. One key enzyme in this change is stearoyl-CoA desaturase-1 (SCD1), which catalyses the monounsaturation of lipids. In order to normalize the lipid composition, we aimed to target a group of nuclear receptors that are important regulators in the lipid synthesis. This group of receptors are known as the peroxisome proliferating activating receptors (PPARs). By (de)activating each isoform (PPAR-α, PPAR-δ and PPAR-γ), the PPAR isoforms may have normalizing effects on the lipid composition. In addition, another PPAR-α agonist Wy14643 was included as this supplement demonstrated normalizing effects in the lipid composition in a more recent study. After PPAR (ant)agonists supplementation, the mRNA of downstream targets, lipid synthesis genes and lipid composition were investigated. The PPAR downstream targets were activated, indicating that the supplements reached the keratinocytes to trigger their effect. However, minimal impact was observed on the lipid composition after PPAR isoform (de) activation. Only the highest concentration Wy14643 resulted in strong, but negative effects on CER composition. Although the novel tested modifications did not result in an improvement, more insight is gained on the nuclear receptors PPARs and their effects on the lipid barrier in full-thickness skin models.

Circulating Biomarkers for Laboratory Diagnostics of Atherosclerosis-Literature Review

Atherosclerosis is still considered a disease burden with long-term damaging processes towards the cardiovascular system. Evaluation of atherosclerotic stages requires the use of independent markers such as those already considered traditional, that remain the main therapeutic target for patients with atherosclerosis, together with emerging biomarkers. The challenge is finding models of predictive markers that are particularly tailored to detect and evaluate the evolution of incipient vascular lesions. Important advances have been made in this field, resulting in a more comprehensible and stronger linkage between the lipidic profile and the continuous inflammatory process. In this paper, we analysed the most recent data from the literature studying the molecular mechanisms of biomarkers and their involvement in the cascade of events that occur in the pathophysiology of atherosclerosis.

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 β-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 β-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.

Ceramides from Sea Red Rice Bran Improve Health Indicators and Increase Stress Resistance of Caenorhabditis elegans through Insulin/IGF-1 Signaling (IIS) Pathway and JNK-1

The antiaging effects of sea red rice bran in vivo, a new saline-tolerant sea rice byproduct containing high levels of ceramides (Cers), remain unknown. This study aimed to explore the antiaging effects exerted by Cers from sea red rice bran on Caenorhabditis elegans, assess its health indicators as well as tolerance, and then reveal the mechanism of action of Cers in prolonging the mean life span through genetic studies. The results indicated that the mean life span of Cers-treated C. elegans were dose-dependent in the range of 0.10-0.50 mg/mL. Additionally, Cers improved nematode motility, reduced lipofuscin accumulation, and enhanced resistance to heat stress and antioxidant enzyme activity. Genetic studies showed that Cers treatment had altered nematode gene expression. In addition, insulin/IGF-1 and jnk-1/mitogen-activated protein kinase (MAPK) signaling pathways successfully demonstrated the longevity effects of Cers intake. In short, these results suggest that Cers enhance the resistance of C. elegans and prolong its life span.

The FKBP51 Inhibitor SAFit2 Restores the Pain-Relieving C16 Dihydroceramide after Nerve Injury

Neuropathic pain is a pathological pain state with a broad symptom scope that affects patients after nerve injuries, but it can also arise after infections or exposure to toxic substances. Current treatment possibilities are still limited because of the low efficacy and severe adverse effects of available therapeutics, highlighting an emerging need for novel analgesics and for a detailed understanding of the pathophysiological alterations in the onset and maintenance of neuropathic pain. Here, we show that the novel and highly specific FKBP51 inhibitor SAFit2 restores lipid signaling and metabolism in nervous tissue after nerve injury. More specifically, we identify that SAFit2 restores the levels of the C16 dihydroceramide, which significantly reduces the sensitization of the pain-mediating TRPV1 channel and subsequently the secretion of the pro-inflammatory neuropeptide CGRP in primary sensory neurons. Furthermore, we show that the C16 dihydroceramide is capable of reducing acute thermal hypersensitivity in a capsaicin mouse model. In conclusion, we report for the first time the C16 dihydroceramide as a novel and crucial lipid mediator in the context of neuropathic pain as it has analgesic properties, contributing to the pain-relieving properties of SAFit2.

Plasma Ceramide Concentrations in Full-Term Pregnancies Complicated with Gestational Diabetes Mellitus: A Case-Control Study

Ceramides, a sphingolipid group that acts as a messenger in cellular differentiation, proliferation, apoptosis and senescence, have been associated with cardiovascular disease and type 2 diabetes. The evidence for an association between ceramides and gestational diabetes mellitus (GDM) is scarce. This case-control study aimed to compare women with GDM with healthy, pregnant women in terms of plasma ceramide concentrations at the time of delivery. Ninety-two pregnant women were included in this case-control study, 29 in the GDM group and 63 in the control group. All women were admitted to a tertiary academic hospital for a full-term delivery. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was applied for the quantification of four molecular ceramides, namely Cer d18:1/16:0 (Cer16:0), Cer d18:1/18:0 (Cer18:0), Cer d18:1/24:0 (Cer24:0) and Cer d18:1/24:1 (Cer24:1) in plasma samples. The raw chromatographic data obtained from the LC-MS/MS analysis were processed using Analyst SCIEX (AB Sciex Pte. Ltd., USA). In a univariate statistical analysis, Cer24:0 concentration was significantly lower in the GDM group compared with the control group (p = 0.01). The present study demonstrated lower Cer24:0 concentrations in pregnancies complicated by GDM. Further prospective studies are required to enhance the results of this study.

Dupilumab significantly improves skin barrier function in patients with moderate-to-severe atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is characterized by abnormal skin lipids that are largely driven by hyperactivated type 2 immune responses. The antibody to the α-subunit of interleukin (IL)-4 receptor, dupilumab, was recently approved to treat AD and demonstrated strong efficacy. However, the role of dupilumab therapy in the regulation of skin barrier structure and function has not been fully explored.

METHODS

We have evaluated the content of lipids and transepidermal water loss (TEWL) in lesional and non-lesional skin of adults and adolescents with moderate-to-severe AD over the course of 16-week treatment with dupilumab and compared those values with that of matched healthy volunteers.

RESULTS

Dupilumab treatment provided a significant decrease in TEWL in AD lesions, lowering it almost to the levels seen in the skin of healthy subjects. Blocking IL-4/IL-13 signaling with dupilumab normalized lipid composition (decreased levels of ceramides with non-hydroxy fatty acids and C18-sphingosine and increased the level of esterified omega-hydroxy fatty acid-containing ceramides) and increased ceramide chain length in lesional as well as non-lesional stratum corneum of AD patients. Partial changes for these parameters were already observed after 2 weeks, with a full response achieved after 8 weeks of dupilumab treatment.

CONCLUSIONS

Inhibition of IL-4/IL-13 signaling by dupilumab allows restoration of skin lipid composition and barrier function in patients with moderate-to-severe AD.

Skin inflammation and impaired adipogenesis in a mouse model of acid ceramidase deficiency

Acid ceramidase catalyzes the degradation of ceramide into sphingosine and a free fatty acid. Acid ceramidase deficiency results in lipid accumulation in many tissues and leads to the development of Farber disease (FD). Typical manifestations of classical FD include formation of subcutaneous nodules and joint contractures as well as the development of a hoarse voice. Healthy skin depends on a unique lipid profile to form a barrier that confers protection from pathogens, prevents excessive water loss, and mediates cell-cell communication. Ceramides comprise ~50% of total epidermis lipids and regulate cutaneous homeostasis and inflammation. Abnormal skin development including visual skin lesions has been reported in FD patients, but a detailed study of FD skin has not been performed. We conducted a pathophysiological study of the skin in our mouse model of FD. We observed altered lipid composition in FD skin dominated by accumulation of all studied ceramide species and buildup of abnormal storage structures affecting mainly the dermis. A deficiency of acid ceramidase activity also led to the activation of inflammatory IL-6/JAK/signal transducer and activator of transcription 3 and noncanonical NF-κB signaling pathways. Last, we report reduced proliferation of FD mouse fibroblasts and adipose-derived stem/stromal cells (ASC) along with impaired differentiation of ASCs into mature adipocytes.

The Urinary Bladder is Rich in Glycosphingolipids Composed of Phytoceramides

Glycosphingolipids (GSLs) are composed of a polar glycan chain and a hydrophobic tail known as ceramide. Together with variation in the glycan chain, ceramides exhibit tissue-specific structural variation in the long-chain base (LCB) and N-acyl chain moieties in terms of carbon chain length, degree of desaturation, and hydroxylation. Here, we report the structural variation in GSLs in the urinary bladders of mice and humans. Using TLC, we showed that the major GSLs are hexosylceramide, lactosylceramide, globotriaosylceramide, globotetraosylceramide, Neu5Ac-Gal-Glc-Ceramide, and Neu5Ac-Neu5Ac-Gal-Glc-Ceramide. Our LC-MS analysis indicated that phytoceramide structures with a 20-carbon LCB (4-hydroxyeicosasphinganine) and 2-hydroxy fatty acids are abundant in hexosylceramide and Neu5Ac-Gal-Glc-Ceramide in mice and humans. In addition, quantitative PCR demonstrated that DES2 and FA2H, which are responsible for the generation of 4-hydroxysphinganine and 2-hydroxy fatty acid, respectively, and SPTLC3 and SPTSSB, which are responsible for the generation of 20-carbon LCBs, showed significant expressions in the epithelial layer than in the subepithelial layer. Immunohistochemically, dihydroceramide:sphinganine C4-hydroxylase (DES2) was expressed exclusively in urothelial cells of the urinary bladder. Our findings suggest that these ceramide structures have an impact on membrane properties of the stretching and shrinking in transitional urothelial cells.

A mass spectrometry imaging and lipidomic investigation reveals aberrant lipid metabolism in the orthotopic mouse glioma

Lipids perform multiple biological functions and reflect the physiology and pathology of cells, tissues, and organs. Here, we sought to understand lipid content in relation to tumor pathology by characterizing phospholipids and sphingolipids in the orthotopic mouse glioma using MALDI MS imaging (MSI) and LC-MS/MS. Unsupervised clustering analysis of the MALDI-MSI data segmented the coronal tumoral brain section into 10 histopathologically salient regions. Heterogeneous decrease of the common saturated phosphatidylcholines (PCs) in the tumor was accompanied by the increase of analogous PCs with one or two additional fatty acyl double bonds and increased lyso-PCs. Polyunsaturated fatty acyl-PCs and ether PCs highlighted the striatal tumor margins, whereas the distributions of other PCs differentiated the cortical and striatal tumor parenchyma. We detected a reduction of SM d18:1/18:0 and the heterogeneous mild increase of SM d18:1/16:0 in the tumor, whereas ceramides accumulated only in a small patch deep in the tumoral parenchyma. LC-MS/MS analyses of phospholipids and sphingolipids complemented the MALDI-MSI observation, providing a snapshot of these lipids in the tumor. Finally, the proposed mechanisms responsible for the tumoral lipid changes were contrasted with our interrogation of gene expression in human glioma. Together, these lipidomic results unveil the aberrant and heterogeneous lipid metabolism in mouse glioma where multiple lipid-associated signaling pathways underline the tumor features, promote the survival, growth, proliferation, and invasion of different tumor cell populations, and implicate the management strategy of a multiple-target approach for glioma and related brain malignancies.

New Ceramides and Cerebrosides from the Deep-Sea Far Eastern Starfish Ceramaster patagonicus

Three new ceramides (1−3) and three new cerebrosides (4, 8, and 9), along with three previously known cerebrosides (ophidiocerebrosides C (5), D (6), and CE-3-2 (7)), were isolated from a deep-sea starfish species, the orange cookie starfish Ceramaster patagonicus. The structures of 1−4, 8, and 9 were determined by the NMR and ESIMS techniques and also through chemical transformations. Ceramides 1−3 contain iso-C21 or C23 Δ9-phytosphingosine as a long-chain base and have C16 or C17 (2R)-2-hydroxy-fatty acids of the normal type. Cerebroside 4 contains C22 Δ9-sphingosine anteiso-type as a long-chain base and (2R)-2-hydroxyheptadecanoic acid of the normal type, while compounds 8 and 9 contain saturated C-17 phytosphingosine anteiso-type as a long-chain base and differ from each other in the length of the polymethylene chain of (2R)-2-hydroxy-fatty acids of the normal type: C23 in 8 and C24 in 9. All the new cerebrosides (4, 8, and 9) have β-D-glucopyranose as a monosaccharide residue. The composition of neutral sphingolipids from C. patagonicus was described for the first time. The investigated compounds 1−3, 5−7, and 9 exhibit slight to moderate cytotoxic activity against human cancer cells (HT-29, SK-MEL-28, and MDA-MB-231) and normal embryonic kidney cells HEK293. Compounds 2, 5, and 6 at a concentration of 20 µM inhibit colony formation of MDA-MB-231 cells by 68%, 54%, and 68%, respectively. The colony-inhibiting activity of compounds 2, 5, and 6 is comparable to the effect of doxorubicin, which reduces the number of colonies by 70% at the same concentration.

The Use of Ceramides to Predict Metabolic Response to Metformin in Women With PCOS

Context

Polycystic ovarian syndrome (PCOS) is a complex disorder in which metabolic abnormalities are associated with reproductive dysfunction. Women with PCOS have increased ceramide concentrations. Previous studies demonstrated that treating metabolic abnormalities of PCOS with metformin improved glucose effectiveness after 12 weeks.

Objective

We evaluated whether, in women with PCOS, lower baseline ceramide, diacylglycerol (DAG), and triacylglycerol (TAG) concentrations were associated with improved metabolic response to metformin.

Methods

Women (n = 29), aged 29 ± 5 years and diagnosed with PCOS by the NIH criteria underwent an intravenous glucose tolerance test (IVGTT) before and after 12-week treatment with metformin (1500 mg per day). Metabolic responders were defined by improved glucose effectiveness, specifically, the ability of glucose to stimulate uptake and suppress production, after metformin treatment.

Results

Twelve weeks of metformin resulted in weight loss (-1.7 ± 2.6 kg, P < 0.01) and a reduction in BMI (-0.6 ± 0.9 kg/m², P < 0.01) with no change in HbA1c. The concentrations of Cer(d18:1/22:0), Cer(d18:1/24:0), total ceramides, total Cer(d16:0), total Cer(d18:2), DAG, dihydrosphingomyelin (DHSM), and TAG decreased after metformin treatment (P < 0.05). Baseline total Cer(d16:0) concentration <204.1 pmol/mL was 82% sensitive (AUC 0.72, P = 0.03) and total DHSM concentration <32237 pmol/mL was 100% specific (AUC 0.73, P = 0.03) in predicting improved metabolic response to metformin, as measured by IVGTT.

Conclusion

Lower total Cer(16:0) and DHSM concentrations are associated with a beneficial metabolic response to metformin in women with PCOS. Based on the known association between higher ceramide levels and type 2 diabetes, the data suggest that metformin improves metabolic parameters in women with mild metabolic derangements.

Ceramide nanoliposomes augment the efficacy of venetoclax and cytarabine in models of acute myeloid leukemia

Despite several new therapeutic options for acute myeloid leukemia (AML), disease relapse remains a significant challenge. We have previously demonstrated that augmenting ceramides can counter various drug-resistance mechanisms, leading to enhanced cell death in cancer cells and extended survival in animal models. Using a nanoscale delivery system for ceramide (ceramide nanoliposomes, CNL), we investigated the effect of CNL within a standard of care venetoclax/cytarabine (Ara-C) regimen. We demonstrate that CNL augmented the efficacy of venetoclax/cytarabine in in vitro, ex vivo, and in vivo models of AML. CNL treatment induced non-apoptotic cytotoxicity, and augmented cell death induced by Ara-C and venetoclax. Mechanistically, CNL reduced both venetoclax (Mcl-1) and cytarabine (Chk1) drug-resistant signaling pathways. Moreover, venetoclax and Ara-C augmented the generation of endogenous pro-death ceramide species, which was intensified with CNL. Taken together, CNL has the potential to be utilized as an adjuvant therapy to improve outcomes, potentially extending survival, in patients with AML.

Modulation of Plasma Lipidomic Profiles in Metastatic Castration-Resistant Prostate Cancer by Simvastatin

Elevated circulating sphingolipids are associated with shorter overall survival and therapeutic resistance in metastatic castration-resistant prostate cancer (mCRPC), suggesting that perturbations in sphingolipid metabolism promotes prostate cancer growth. This study assessed whether addition of simvastatin to standard treatment for mCRPC can modify a poor prognostic circulating lipidomic profile represented by a validated 3-lipid signature (3LS). Men with mCRPC (n = 27) who were not on a lipid-lowering agent, were given simvastatin for 12 weeks (40 mg orally, once daily) with commencement of standard treatment. Lipidomic profiling was performed on their plasma sampled at baseline and after 12 weeks of treatment. Only 11 men had the poor prognostic 3LS at baseline, of whom five (45%) did not retain the 3LS after simvastatin treatment (expected conversion rate with standard treatment = 19%). At baseline, the plasma profiles of men with the 3LS displayed higher levels (p < 0.05) of sphingolipids (ceramides, hexosylceramides and sphingomyelins) than those of men without the 3LS. These plasma sphingolipids were reduced after statin treatment in men who lost the 3LS (mean decrease: 23−52%, p < 0.05), but not in men with persistent 3LS, and were independent of changes to plasma cholesterol, LDL-C or triacylglycerol. In conclusion, simvastatin in addition to standard treatment can modify the poor prognostic circulating lipidomic profile in mCRPC into a more favourable profile at twice the expected conversion rate.

Targeting Ceramides and Adiponectin Receptors in the Islet of Langerhans for Treating Diabetes

Ceramides belong to the sphingolipid family and represent the central hub of the sphingolipid network. In obesity, oversupply of saturated fatty acids including palmitate raises ceramide levels which can be detrimental to cells. Elevated ceramides can cause insulin resistance, endoplasmic reticulum stress, and mitochondrial dysfunction. Studies over the last few decades have highlighted the role played by ceramides in pancreatic islet β-cell apoptosis, especially under glucolipotoxic and inflammatory conditions. This review focuses on ceramides and adiponectin receptor signaling, summarizing recent advancements in our understanding of their roles in islet β-cells and the discovery of zinc-dependent lipid hydrolase (ceramidase) activity of adiponectin receptors. The therapeutic potential of targeting these events to prevent islet β-cell loss for treating diabetes is discussed.

Effects of a 0.3% cholesterol diet and a 20% fat diet on plasma lipids and lipoproteins in Quaker parrots (Myiopsitta monachus)

BACKGROUND

Lipid disorders are common in captive psittacine birds, but associated changes in blood lipids and lipoproteins have not been well characterized. The Quaker parrot is prone to dyslipidemia and has been extensively used as an experimental model.

OBJECTIVES

We aimed to study the effects of a 0.3% cholesterol diet and a 20% fat diet on plasma lipids and lipoproteins in Quaker parrots.

METHODS

Two crossover studies were performed with each diet. During each study, 12 parrots were divided into two groups fed the treatment or control diet for 2 weeks. After a 2-month wash-out period, the groups were reversed. At the end of each period, plasma lipidomics and lipoprotein profiling were performed. Data were analyzed by univariate tests adjusted for false discovery rates, volcano plots, and enrichment analyses.

RESULTS

The cholesterol diet induced changes in many plasma lipids and lipoproteins. Total cholesterol and cholesteryl esters were significantly and markedly elevated. Ceramides were the second subclass of lipids that were elevated. Several glycerophosphocholines, sphingomyelins, and one diacylglycerol were also significantly elevated, albeit to a lesser magnitude. All lipoproteins were elevated, with the greatest increase seen in non-HDL. The fat diet mainly resulted in a decrease in plasma glycerolipids and an increase in acylcarnitines. Lipoprotein plasma levels remained unchanged.

CONCLUSIONS

Quaker parrots fed a 0.3% cholesterol diet showed profound and complex dyslipidemic changes that could be used to further study lipid disorders and their management in psittacine birds. A 20% fat diet higher in n-6 polyunsaturated fatty acids did not lead to dyslipidemia.

Machine Learning Algorithm to Predict Obstructive Coronary Artery Disease: Insights from the CorLipid Trial

Developing risk assessment tools for CAD prediction remains challenging nowadays. We developed an ML predictive algorithm based on metabolic and clinical data for determining the severity of CAD, as assessed via the SYNTAX score. Analytical methods were developed to determine serum blood levels of specific ceramides, acyl-carnitines, fatty acids, and proteins such as galectin-3, adiponectin, and APOB/APOA1 ratio. Patients were grouped into: obstructive CAD (SS > 0) and non-obstructive CAD (SS = 0). A risk prediction algorithm (boosted ensemble algorithm XGBoost) was developed by combining clinical characteristics with established and novel biomarkers to identify patients at high risk for complex CAD. The study population comprised 958 patients (CorLipid trial (NCT04580173)), with no prior CAD, who underwent coronary angiography. Of them, 533 (55.6%) suffered ACS, 170 (17.7%) presented with NSTEMI, 222 (23.2%) with STEMI, and 141 (14.7%) with unstable angina. Of the total sample, 681 (71%) had obstructive CAD. The algorithm dataset was 73 biochemical parameters and metabolic biomarkers as well as anthropometric and medical history variables. The performance of the XGBoost algorithm had an AUC value of 0.725 (95% CI: 0.691−0.759). Thus, a ML model incorporating clinical features in addition to certain metabolic features can estimate the pre-test likelihood of obstructive CAD.

Ceramide Acyl Chain Length and Its Relevance to Intracellular Lipid Regulation

Ceramides are a class of sphingolipids which are implicated in skin disorders, obesity, and other metabolic diseases. As a class with pleiotropic effects, recent efforts have centred on discerning specific ceramide species and their effects on atopic dermatitis, obesity, type 2 diabetes, and cardiovascular diseases. This delineation has allowed the identification of disease biomarkers, with long acyl chain ceramides such as C16- and C18-ceramides linked to metabolic dysfunction and cardiac function decline, while ultra-long acyl chain ceramides (>25 carbon acyl chain) were reported to be essential for maintaining a functional skin barrier. Given the intricate link between free fatty acids with ceramides, especially the de novo synthetic pathway, intracellular lipid droplet formation is increasingly viewed as an important mechanism for preventing accumulation of toxic ceramide species. Here, we review recent reports of various ceramide species involved in skin abnormalities and metabolic diseases, and we propose that promotion of lipid droplet biogenesis can be seen as a potential protective mechanism against deleterious ceramides.

Ceramide Metabolism in Cardiovascular Disease: A Network With High Therapeutic Potential

Growing evidence suggests that ceramides play an important role in the development of atherosclerotic and valvular heart disease. Ceramides are biologically active sphingolipids that are produced by a complex network of enzymes. Lowering cellular and tissue levels of ceramide by inhibiting the ceramide-producing enzymes counteracts atherosclerotic and valvular heart disease development in animal models. In vascular tissues, ceramides are produced in response to hyperglycemia and TNF (tumor necrosis factor)-α signaling and are involved in NO-signaling and inflammation. In humans, elevated blood ceramide levels are associated with cardiovascular events. Furthermore, important cardiovascular risk factors, such as obesity and diabetes, have been linked to ceramide accumulation. This review summarizes the basic mechanisms of how ceramides drive cardiovascular disease locally and links these findings to the intriguing results of human studies on ceramides as biomarkers for cardiovascular events. Moreover, we discuss the current state of interventions to therapeutically influence vascular ceramide metabolism, both locally and systemically.

Skin Penetration Enhancer-Incorporated Lipid Nanovesicles (SPE-LNV) for Skin Brightening and Wrinkle Treatment

In this work, we utilize skin penetration enhancers (SPEs) such as ceramide and fatty acids in lipid nanovesicles to promote the transdermal delivery of active ingredients. These SPE-incorporated lipid nanovesicles (SPE-LNV) interact with the constituents of skin's outermost stratum corneum (SC) layer, enabling even niacinamide and adenosine with high water solubility to effectively permeate through, leading to enhanced skin efficacy. We demonstrate by both in vitro and in vivo skin permeation studies that the SPE-LNV formulation containing both ceramide and fatty acids (LNV-CF) exhibits deeper penetration depth and faster permeation rate compared to conventional lipid nanovesicles (LNV) without SPE as well as LNV-C with only ceramide. Moreover, in vivo clinical trials were also performed to confirm that LNV-CF most effectively mediates the delivery of niacinamide and adenosine, resulting in a substantial decrease in melanin index as well as skin wrinkle compared to the control groups. We envision that the strategy of incorporating both ceramide and fatty acids in lipid nanovesicles offers a simple and convenient route for the rapid and effective delivery of water-soluble active ingredients across the skin barrier layer.

The ketogenic diet prevents steatosis and insulin resistance by reducing lipogenesis, diacylglycerol accummulation, and PKC activity in male rat liver

KEY POINTS

The accumulation of diacylglycerol (DAG), ceramides and inflammation are key factors that cause insulin resistance and nonalcoholic fatty liver (NAFLD). This study provides evidence that a ketogenic diet (KD) rich in fat and devoid of carbohydrate reduced DAG content and preserved insulin signalling in the liver. The KD shifted metabolism away from lipogenesis by enhancing genes involved in mitochondrial biogenesis and fatty acid oxidations in the liver. The KD also promoted the production of beneficial very long-chain ceramides instead of potentially harmful long-chain ceramides. Through multiple mechanisms, the KD exerted anti-steatogenic and insulin-sensitizing effects in the liver, which supports the use of this dietary intervention to treat NAFLD.

ABSTRACT

Obesity-associated insulin resistance plays a major role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). The accumulation of diacylglycerol (DAG), ceramides and inflammation are key factors that cause NAFLD. In recent years, the ketogenic diet (KD) has emerged as an effective non-pharmacological intervention for the treatment of NAFLD and other obesity-related metabolic disorders. What remains undetermined is how the KD affects DAG and ceramides content and insulin sensitivity in the liver. Thus, this research was designed to assess these variables, as well as glucose and fat metabolism and markers of inflammation in livers of rats exposed for 8 weeks to one of the following diets: standard chow (SC), obesogenic high-fat, sucrose-enriched diet (HFS), or a KD. Despite having a higher fat content than the HFS diet, the KD did not cause steatosis and preserved hepatic insulin signalling. The KD reduced DAG content and protein kinase C epsilon (PKCε) activity, but markedly increased liver ceramides content. However, whereas the KD increased ceramide synthase 2 (CerS2) expression, it suppressed CerS6 expression, an effect that promoted the production of beneficial very long-chain ceramides instead of harmful long-chain ceramides. The KD also enhanced the liver expression of key genes involved in mitochondrial biogenesis and fatty acid oxidation (Pgc-1α and Fgf21), suppressed inflammatory genes (Tnfα, Nf-kb, Tlr4, and Il6), and shifted substrate away from de-novo lipogenesis. Thus, through multiple mechanisms the KD exerted anti-steatogenic and insulin-sensitizing effects in the liver, which supports the use of this dietary intervention to treat NAFLD. Abstract figure legend This article is protected by copyright. All rights reserved.