Association between specific plasma ceramides and high-sensitivity C-reactive protein levels in postmenopausal women with type 2 diabetes

Scavenger Receptor BI Deficiency in Mice Is Associated With Plasma Ceramide and Sphingomyelin Accumulation and a Reduced Cholesteryl Ester Fatty Acid Length and Unsaturation Degree

Objective

Scavenger receptor class B type I (SR-BI) is primarily known for its role in the selective uptake of cholesteryl esters (CEs) from high-density lipoproteins (HDLs). Here we investigated whether SR-BI deficiency is associated with other potentially relevant changes in the plasma lipidome than the established effect of HDL-cholesterol elevation.

Methods

Targeted ultra-high-performance liquid chromatography-tandem mass spectrometry was utilized to measure lipid species in plasma from female wild-type and SR-BI knockout mice.

Results

SR-BI deficiency was associated with a reduction in the average CE fatty acid length (-2%; p<0.001) and degree of CE fatty acid unsaturation (-18%; p<0.001) due to a relative shift from longer, polyunsaturated CE species CE (20:4), CE (20:5), and CE (22:6) towards the mono-unsaturated CE (18:1) species. Sphingomyelin (SM) levels were 64% higher (p<0.001) in SR-BI knockout mice without a parallel change in (lyso)phosphatidylcholine (LPC) concentrations, resulting in an increase in the SM/LPC ratio from 0.102±0.005 to 0.163±0.003 (p<0.001). In addition, lower LPC lengths (-5%; p<0.05) and fatty acid unsaturation degrees (-20%; p<0.01) were detected in SR-BI knockout mice. Furthermore, SR-BI deficiency was associated with a 4.7-fold increase (p<0.001) in total plasma ceramide (Cer) levels, with a marked >9-fold rise (p<0.001) in Cer (d18:1/24:1) concentrations.

Conclusion

We have shown that SR-BI deficiency in mice not only impacts the CE concentrations, length, and saturation index within the plasma compartment, but is also associated with plasma accumulation of several Cer and SM species that may contribute to the development of specific hematological and metabolic (disease) phenotypes previously detected in SR-BI knockout mice.

Exposure to ambient oxidant pollution associated with ceramide changes and cardiometabolic responses

Evidence of impact of ambient oxidant pollution on cardiometabolic responses remains limited. We aimed to examine associations of oxidant pollutants with cardiometabolic responses, and effect modification by ceramides. During 2019-2020, 152 healthy adults were visited 4 times in Beijing, China, and indicators of ceramides, glucose homeostasis, and vascular function were measured. We found significant increases in ceramides of 13.9% (p = 0.020) to 110.1% (p = 0.005) associated with an interquartile increase in oxidant pollutants at prior 1-7 days. Exposure to oxidant pollutants was also related to elevations in insulin and reductions in adiponectin, and elevations in systolic and diastolic blood pressure. Further, stratified analyses revealed larger changes in oxidant pollutant related cardiometabolic responses among participants with higher ceramide levels compared to those with lower levels. Our findings suggested cardiometabolic effects associated with exposure to oxidant pollutants, which may be modified by ceramide levels.

Lysophosphatidylcholines and phosphatidylcholines as biomarkers for stroke recovery

Stroke is a serious global public health issue, associated with severe disability and high mortality rates. Its early detection is challenging, and no effective biomarkers are available. To obtain a better understanding of stroke prevention, management, and recovery, we conducted lipidomic analyses to characterize plasma metabolic features. Lipid species were measured using an untargeted lipidomic analysis with liquid chromatography-tandem mass spectrometry. Sixty participants were recruited in this cohort study, including 20 healthy individuals and 40 patients with stroke. To investigate the association between lipids related to long-term functional recovery in stroke patients. The primary independent variable was activities of daily living (ADL) dependency upon admission to the stroke unit and at the 3-month follow-up appointment. ADL dependency was assessed using the Barthel Index. Eleven significantly altered lipid species between the stroke and healthy groups were detected and displayed in a hierarchically clustered heatmap. Acyl carnitine, triacylglycerol, and ceramides were detected as potential lipid markers. Regarding the association between lipid profiles and functional status of patients with stroke the results indicated, lysophosphatidylcholines (LPC) and phosphatidylcholines were closely associated with stroke recovery. LPC may contribute positively role in patient's rehabilitation process via an anti-inflammatory mechanism. Appropriate management or intervention for lipid levels is expected to lead to better clinical outcomes.

Association between Higher Circulating Leucine-Rich α-2 Glycoprotein 1 Concentrations and Specific Plasma Ceramides in Postmenopausal Women with Type 2 Diabetes

Background: Although ceramides are involved in the pathophysiology of cardiovascular disease and other inflammation-associated disorders, there is a paucity of data on the association between plasma ceramides and inflammatory biomarkers in type 2 diabetes mellitus (T2DM). Therefore, we explored whether there was an association between plasma leucine-rich α-2 glycoprotein 1 (LRG1) concentrations (i.e., a novel proinflammatory signaling molecule) and specific plasma ceramides in postmenopausal women with T2DM. Methods: We measured six previously identified plasma ceramides, which have been associated with increased cardiovascular risk [plasma Cer(d18:1/16:0), Cer(d18:1/18:0), Cer(d18:1/20:0), Cer(d18:1/22:0), Cer(d18:1/24:0) and Cer(d18:1/24:1)], amongst 99 Caucasian postmenopausal women with non-insulin-treated T2DM (mean age 72 ± 8 years, mean hemoglobin A1c 6.9 ± 0.7%), who consecutively attended our diabetes outpatient service during a 3-month period. Plasma ceramide and LRG1 concentrations were measured with a targeted liquid chromatography-tandem mass spectrometry assay and a Milliplex® MAP human cardiovascular disease magnetic bead kit, respectively. Results: In linear regression analyses, higher plasma LRG1 levels (1st tertile vs. 2nd and 3rd tertiles combined) were associated with higher levels of plasma Cer(d18:1/16:0) (standardized β coefficient: 0.289, p = 0.004), Cer(d18:1/18:0) (standardized β coefficient: 0.307, p = 0.002), Cer(d18:1/20:0) (standardized β coefficient: 0.261, p = 0.009) or Cer(d18:1/24:1) (standardized β coefficient: 0.343, p < 0.001). These associations remained significant even after adjusting for age, body mass index, systolic blood pressure, total cholesterol level, hemoglobin A1c, insulin resistance and statin use. Conclusions: The results of our pilot exploratory study suggest that higher plasma LRG1 concentration was associated with higher levels of specific high-risk plasma ceramide molecules in elderly postmenopausal women with metabolically well-controlled T2DM, even after adjusting for known cardiovascular risk factors and other potential confounding variables.

Ceramides and Cardiovascular Risk Factors, Inflammatory Parameters and Left Ventricular Function in AMI Patients

Background: Ceramides, biologically active lipids correlated to oxidative stress and inflammation, have been associated with adverse outcomes in acute myocardial infarction (AMI). The purpose of this study was to assess the association between ceramides/ratios included in the CERT1 score and increased cardiovascular (CV) risk, inflammatory and left ventricular function parameters in AMI. Methods: high performance liquid chromatography-tandem mass spectrometry was used to identify Cer(d18:1/16:0), Cer(d18:1/18:0), and Cer(d18:1/24:1) levels and their ratios to Cer(d18:1/24:0), in 123 AMI patients (FTGM coronary unit, Massa, Italy). Results: Cer(d18:1/16:0): higher in female patients (<0.05), in patients with dyslipidemia (<0.05), and it directly and significantly correlated with aging, brain natriuretic peptide-BNP, erythrocyte sedimentation rate-ESR and fibrinogen. Cer(d18:1/18:0): higher in females (<0.01) and patients with dyslipidemia (<0.01), and increased according to the number of CV risk factors (considering hypertension, dyslipidemia and diabetes). Moreover, it significantly correlated with BNP, troponin at admission, ESR, C reactive protein-CRP, and fibrinogen. Cer(d18:1/24:1): significantly correlated with aging, BNP, fibrinogen and neutrophils. Cer(d18:1/16:0)/Cer(d18:1/24:0): higher in female patients (<0.05), and in patients with higher wall motion score index-WMSI (>1.7; ≤0.05), and in those with multivessel disease (<0.05). Moreover, it significantly correlated with aging, BNP, CRP, ESR, neutrophil-to-lymphocyte ratio-NRL, and fibrinogen. Cer(d18:1/18:0)/Cer(d18:1/24:0): higher in female patients (<0.001), and increased according to age. Moreover, it was higher in patients with lower left ventricular ejection fraction (<35%, ≤0.01), higher WMSI (>1.7, <0.05), and in those with multivessel disease (0.13 ± 0.06 vs. 0.10 ± 0.05 µM, <0.05), and correlates with BNP, ESR, CRP, fibrinogen and neutrophils, platelets, NLR, and troponin at admission. Multiple regression analysis showed that Cer(d18:1/16:0)/Cer(d18:1/24:0) and Cer(d18:1/18:0)/Cer(d18:1/24:0) remained as independent determinants for WMSI after multivariate adjustment (Std coeff 0.17, T-value 1.9, ≤0.05; 0.21, 2.6, <0.05, respectively). Conclusion: Distinct ceramide species are associated with CV risk, inflammation and disease severity in AMI. Thus, a detailed analysis of ceramides may help to better understand CV pathobiology and suggest these new biomarkers as possible risk predictors and pharmacological targets in AMI patients.

Ceramides and other sphingolipids as drivers of cardiovascular disease

Increases in calorie consumption and sedentary lifestyles are fuelling a global pandemic of cardiometabolic diseases, including coronary artery disease, diabetes mellitus, cardiomyopathy and heart failure. These lifestyle factors, when combined with genetic predispositions, increase the levels of circulating lipids, which can accumulate in non-adipose tissues, including blood vessel walls and the heart. The metabolism of these lipids produces bioactive intermediates that disrupt cellular function and survival. A compelling body of evidence suggests that sphingolipids, such as ceramides, account for much of the tissue damage in these cardiometabolic diseases. In humans, serum ceramide levels are proving to be accurate biomarkers of adverse cardiovascular disease outcomes. In mice and rats, pharmacological inhibition or depletion of enzymes driving de novo ceramide synthesis prevents the development of diabetes, atherosclerosis, hypertension and heart failure. In cultured cells and isolated tissues, ceramides perturb mitochondrial function, block fuel usage, disrupt vasodilatation and promote apoptosis. In this Review, we discuss the body of literature suggesting that ceramides are drivers - and not merely passengers - on the road to cardiovascular disease. Moreover, we explore the feasibility of therapeutic strategies to lower ceramide levels to improve cardiovascular health.

Association between ceramides and coronary artery stenosis in patients with coronary artery disease

BACKGROUND

Coronary artery stenosis induces heart diseases including acute coronary syndrome (ACS). Some studies reported the ceramide species are associated with the ACS and major adverse cardia and cerebrovascular events (MACE). However, few studies investigated the association between plasma ceramide levels and the severity of stenosis, together with the onset of diseases. This aim of the present study was to investigate the association betweencertain ceramide species, coronary artery stenosis and acute coronary syndrome.

METHODS

Five hundred fifty-three patients with definite or suspected CAD were recruited and received angiography. Subjects were assigned into 4 groups according to the severity of coronary artery stenosis. The measurements of 4 plasma ceramide species, namely, Cer (d18:1/16:0), Cer (d18:1/18:0), Cer (d18:1/24:1), Cer (d18:1/24:0) were carried out by Liquid chromatography-tandem mass spectrometry (LC-MS/MS) and the ratio of Cer (d18:1/16:0), Cer (d18:1/18:0) and Cer (d18:1/24:1) to Cer (18:1/24:0), respectively, were calculated as index to evaluate the association between plasma ceramides levels and coronary artery stenosis. Multiple logistic regression analysis was used to establish the prognostic model for the prediction of ACS risk.

RESULTS

After the adjustment by multiple clinical risk factors including age, gender, pre-existing myocardial/cerebral infarction, hemoglobin A1c% (HbA1c%), smoking and the diagnosis during index hospitalization, multiple logistic regression analysis showed that the high ratio of Cer (d18:1/24:1) to Cer (d18:1/24:0), female gender, HbA1c%, unstable angina (UAP) and acute myocardial infarction (AMI) diagnosis (compared with atherosclerosis) during index hospitalization were associated with more severe coronary artery stenosis. Furthermore, the prognostic model was established after adjustment of risk factors and the area under curve (AUC) of receiver operating characteristics (ROC) for the prognostic model was 0.732 and 95% CI was 0.642-0.822.

CONCLUSION

The severity of coronary artery stenosis is associated with high ratio of Cer (d18:1/24:1) to Cer (d18:1/24:0), female gender, HbA1c% and AMI. Although the reported prognostic model showed a good discrimination, further investigation on long term MACE is needed to evaluate the role of ceramide for the prediction of MACE risk.

Plasma levels of ceramides relate to ischemic stroke risk and clinical severity

Recent studies have suggested that specific plasma ceramides are independently associated with atherosclerosis and cardiovascular diseases, but it is currently unknown whether plasma ceramide levels are associated with ischemic stroke. Here, we examined whether ceramides were associated with both ischemic stroke risk and clinical severity at admission. We measured three previously identified high-risk plasma ceramide molecules [Cer(d18:1/16:0), Cer(d18:1/22:0), and Cer(d18:1/24:0)] in 202 patients with acute ischemic stroke and 202 age and sex matched control cases. Plasma ceramides levels were measured by a targeted liquid chromatography-tandem mass spectrometry assay at baseline. The median age of the 202 stroke patients was 66 (interquartile range [IQR], 58-75) years and 54.0 % were men. Plasma levels of C16:0, C22:0, and C24:0 ceramides in stroke patients were significantly higher than in those control cases (P < 0.001, all). In multivariate logistic regression analysis adjusted for other risk factors, higher levels of C16:0, C22:0, and C24:0 ceramides were associated with higher risk of ischemic stroke (odd ratio [OR] for one IQR increase: 2.15[1.42-2.99]; 2.90[2.13-4.01] and 1.29[1.10-1.69]; respectively). At admission, 103 patients (51.0 %) had a minor stroke (NIHSS < 6). In these patients, plasma levels of C16:0, C22:0, and C24:0 ceramides were lower than that observed in patients with moderate-to-high clinical severity (P < 0.001, all). In multivariate logistic regression analysis adjusted for other risk factors, higher levels of C16:0, C22:0, and C24:0 ceramides were associated with higher risk of moderate-to-high stroke (OR for one IQR increase: 2.96 [2.05-4.22], 3.03 [2.01-4.25] and 1.72 [1.25-3.31], respectively). An elevated plasma levels of ceramides were predictors of both risk and severity at admission in ischemic stroke patients. The underlying mechanisms of these associations remain to be investigated.