Free cholesterol, cholesterol precursor and plant sterol levels in atherosclerotic plaques are independently associated with symptomatic advanced carotid artery stenosis

(Pre)Clinical Metabolomics Analysis

Metabolomics is the scientific field with the eager goal to comprehensively analyze the entirety of all small molecules of a biological system, i.e., the metabolome. Over the last few years, metabolomics has matured to become an analytical cornerstone of life science research across diverse fields, from fundamental biochemical applications to preclinical studies, including biomarker discovery and drug development. In this chapter, we provide an introduction to (pre)clinical metabolomics. We define key metabolomics aspects and provide the basis to thoroughly understand the relevance of this field in a biological and clinical context. We present and explain state-of-the-art analytical technologies devoted to metabolomic analysis as well as emerging technologies, discussing both strengths and weaknesses. Given the ever-increasing demand for handling complex datasets, the role of bioinformatics approaches in the context of metabolomic analysis is also illustrated.

Inflammation and oxidative stress markers in type 2 diabetes patients with Advanced Carotid atherosclerosis

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a major global health issue and a significant risk factor for atherosclerosis. Atherosclerosis in T2DM patients has been associated with inflammation, insulin resistance, hyperglycemia, dyslipidemia, and oxidative stress. Identifying molecular features of atherosclerotic plaques in T2DM patients could provide valuable insights into the pathogenesis of the disease.

METHODS

The MASCADI (Arachidonic Acid Metabolism in Carotid Stenosis Plaque in Diabetic Patients) study aimed to investigate the increase of 2-arachidonoyl-lysophatidylcholine (2-AA-LPC) in carotid plaques from T2DM and control patients and to explore its association with plaque vulnerability as well as with blood and intra-plaque biomarkers altered during diabetes.

RESULTS

In a population of elderly, polymedicated patients with advanced stage of atherosclerosis, we found that T2DM patients had higher systemic inflammation markers, such as high-sensitivity C-reactive protein (hsCRP) and IL-1β, higher levels of oxysterols, increased triglyceride levels, and decreased HDL levels as compared to control patients. Furthermore, 2-AA-LPC was significantly enriched in plaques from diabetic patients, suggesting its potential role in diabetic atherosclerosis. Interestingly, 2-AA-LPC was not associated with systemic markers related to diabetes, such as hsCRP, triglycerides, or HDL cholesterol. However, it was significantly correlated with the levels of inflammatory markers within the plaques such as lysophospholipids and 25-hydroxycholesterol, strengthening the link between local inflammation, arachidonic acid metabolism and diabetes.

CONCLUSION

Our study is in line with a key role for inflammation in the pathogenesis of diabetic atherosclerosis and highlights the involvement of 2-AA-LPC. Further research is needed to better understand the local processes involved in the alteration of plaque composition in T2DM and to identify potential therapeutic targets.

TRIAL REGISTRATION

The MASCADI was registered on ClinicalTrials.gov (clinical registration number: NCT03202823).

Blood phytosterols in relation to cardiovascular diseases and mediating effects of blood lipids and hematological traits: a Mendelian randomization analysis

BACKGROUND

Short-term clinical trials have shown the cholesterol-lowering potentials of phytosterols, but their impacts on cardiovascular disease (CVD) remain controversial. This study used the Mendelian randomization (MR) to investigate the relationships between genetic predisposition to blood sitosterol concentration and 11 CVD endpoints, along with the potential mediating effects of blood lipids and hematological traits.

METHODS

Random-effect inverse-variance weighted method was used as the main analysis of MR. Genetic instruments of sitosterol (seven SNPs, F = 253, and R² = 15.4 %) were derived from an Icelandic cohort. Summary-level data of the 11 CVDs were obtained from UK Biobank, FinnGen, and publicly available genome-wide association study results.

RESULTS

Genetically predicted one unit increment in log-transformed blood total sitosterol was significantly associated with a higher risk of coronary atherosclerosis (OR: 1.52; 95 % CI: 1.41, 1.65; n = 667,551), myocardial infarction (OR: 1.40; 95 % CI: 1.25, 1.56; n = 596,436), all coronary heart disease (OR: 1.33; 95 % CI: 1.22, 1.46; n = 766,053), intracerebral hemorrhage (OR: 1.68; 95 % CI: 1.24, 2.27; n = 659,181), heart failure (OR: 1.16; 95 % CI: 1.08, 1.25; n = 1,195,531), and aortic aneurysm (OR: 1.74; 95 % CI: 1.42, 2.13; n = 665,714). Suggestive associations were observed for an increased risk of ischemic stroke (OR: 1.06; 95 % CI: 1.01, 1.12; n = 2,021,995) and peripheral artery disease (OR: 1.20; 95 % CI: 1.05, 1.37; n = 660,791). Notably, blood non-high-density lipoprotein cholesterol (nonHDL-C) and apolipoprotein B mediated about 38-47 %, 46-60 %, and 43-58 % of the associations between sitosterol and coronary atherosclerosis, myocardial infarction, and coronary heart disease, respectively. However, the associations between sitosterol and CVDs were less likely to depend on hematological traits.

CONCLUSION

The study suggests that genetic predisposition to higher blood total sitosterol is linked to a greater risk of major CVDs. Moreover, blood nonHDL-C and apolipoprotein B might mediate a significant proportion of the associations between sitosterol and coronary diseases.

Increased cholesterol absorption is associated with In-stent-restenosis after stent implantation for stable coronary artery disease

BACKGROUND AND AIMS

Blood cholesterol levels are regulated by competing mechanisms of cholesterol synthesis, absorption and excretion. Plant sterols are natural constituents of plants, are not synthesized in humans, and serve as markers for cholesterol absorption. Ezetimibe lowers the intestinal absorption of cholesterol and plant sterols. We analyzed the associations of differences in cholesterol metabolism, in particular increased cholesterol absorption, and the occurrence of in-stent restenosis (ISR) in patients with stable coronary artery disease.

METHODS

Elective stent implantation of de novo stenosis was conducted in 59 patients (74.6 % males, 67.2 ± 9.6 years). Cholesterol and non-cholesterol sterols were quantified in serum samples by gas chromatography or mass spectrometry. ISR was assessed by optical coherence tomography (OCT) and quantitative angiography (QCA) after six months.

RESULTS

Markers for cholesterol absorption (e.g. campesterol-to-cholesterol) were positively associated with ISR measured by QCA (%diameter stenosis, late lumen loss) and OCT (proliferation volume, %area stenosis), whereas markers for cholesterol synthesis (e.g. lathosterol-to-cholesterol) were negatively associated with ISR (%area stenosis: r = -0.271, p = 0.043). There was no association between ISR and total cholesterol, LDL, HDL, triglycerides. Markers for cholesterol absorption (e.g. campesterol-to-cholesterol) were significantly lower in ezetimibe-treated patients compared to patients on a statin only (1.29 ± 0.69 vs. 2.22 ± 1.23; p = 0.007). Combined lipid-lowering with ezetimibe plus statin reduced ISR compared to statin only (13.7 ± 10.4 vs. 22.5 ± 12.1 %diameter stenosis, p = 0.015).

CONCLUSIONS

Differences in cholesterol metabolism, more specifically increased cholesterol absorption, are associated with ISR.

New Function of Cholesterol Oxidation Products Involved in Osteoporosis Pathogenesis

Osteoporosis (OP) is a systemic bone disease characterized by decreased bone strength, microarchitectural changes in bone tissues, and increased risk of fracture. Its occurrence is closely related to various factors such as aging, genetic factors, living habits, and nutritional deficiencies as well as the disturbance of bone homeostasis. The dysregulation of bone metabolism is regarded as one of the key influencing factors causing OP. Cholesterol oxidation products (COPs) are important compounds in the maintenance of bone metabolic homeostasis by participating in several important biological processes such as the differentiation of mesenchymal stem cells, bone formation in osteoblasts, and bone resorption in osteoclasts. The effects of specific COPs on mesenchymal stem cells are mainly manifested by promoting osteoblast genesis and inhibiting adipocyte genesis. This review aims to elucidate the biological roles of COPs in OP development, starting from the molecular mechanisms of OP, pointing out opportunities and challenges in current research, and providing new ideas and perspectives for further studies of OP pathogenesis.

Molecular Probes, Chemosensors, and Nanosensors for Optical Detection of Biorelevant Molecules and Ions in Aqueous Media and Biofluids

Synthetic molecular probes, chemosensors, and nanosensors used in combination with innovative assay protocols hold great potential for the development of robust, low-cost, and fast-responding sensors that are applicable in biofluids (urine, blood, and saliva). Particularly, the development of sensors for metabolites, neurotransmitters, drugs, and inorganic ions is highly desirable due to a lack of suitable biosensors. In addition, the monitoring and analysis of metabolic and signaling networks in cells and organisms by optical probes and chemosensors is becoming increasingly important in molecular biology and medicine. Thus, new perspectives for personalized diagnostics, theranostics, and biochemical/medical research will be unlocked when standing limitations of artificial binders and receptors are overcome. In this review, we survey synthetic sensing systems that have promising (future) application potential for the detection of small molecules, cations, and anions in aqueous media and biofluids. Special attention was given to sensing systems that provide a readily measurable optical signal through dynamic covalent chemistry, supramolecular host-guest interactions, or nanoparticles featuring plasmonic effects. This review shall also enable the reader to evaluate the current performance of molecular probes, chemosensors, and nanosensors in terms of sensitivity and selectivity with respect to practical requirement, and thereby inspiring new ideas for the development of further advanced systems.

Genome-wide meta-analysis of phytosterols reveals five novel loci and a detrimental effect on coronary atherosclerosis

Phytosterol serum concentrations are under tight genetic control. The relationship between phytosterols and coronary artery disease (CAD) is controversially discussed. We perform a genome-wide meta-analysis of 32 phytosterol traits reflecting resorption, cholesterol synthesis and esterification in six studies with up to 9758 subjects and detect ten independent genome-wide significant SNPs at seven genomic loci. We confirm previously established associations at ABCG5/8 and ABO and demonstrate an extended locus heterogeneity at ABCG5/8 with different functional mechanisms. New loci comprise HMGCR, NPC1L1, PNLIPRP2, SCARB1 and APOE. Based on these results, we perform Mendelian Randomization analyses (MR) revealing a risk-increasing causal relationship of sitosterol serum concentrations and CAD, which is partly mediated by cholesterol. Here we report that phytosterols are polygenic traits. MR add evidence of both, direct and indirect causal effects of sitosterol on CAD.

Plasma advanced glycation end products and soluble receptor for advanced glycation end products as indicators of sterol content in human carotid atherosclerotic plaques

Advanced glycation end products (AGEs) are independently related to cardiovascular disease (CVD) and favor cholesterol and oxysterol accumulation in macrophage foam cells. Soluble RAGE (sRAGE) impairs cellular AGE signaling alleviating the deleterious effects of AGE in atherogenesis. The association between plasma AGEs and sRAGE with the content of cholesterol, markers of cholesterol synthesis and absorption, and oxysterols in atherosclerotic plaques was evaluated in subjects undergoing carotid endarterectomy.Plasma and carotid plaques were obtained from symptomatic (n = 23) and asymptomatic subjects (n = 40). Lipids from plaques were extracted and sterols (oxysterols, cholesterol, desmosterol, lathosterol, sitosterol, and campesterol) were determined by using gas chromatography/mass spectrometry. Plasma total AGEs and pentosidine were measured by using fluorimetry and sRAGE by using ELISA.In symptomatic subjects´ atherosclerotic plaques, an increased amount of cholesterol (3x) and oxysterols [7 α-hydroxycholesterol (1.4x); 7 β-hydroxycholesterol (1.2x); 25-hydroxycholesterol (1.3x); 24-hydroxycholesterol (2.7x), and 27-hydroxycholesterol, (1.15x)], with exception to 7 ketocholesterol, were found in comparison to asymptomatic individuals. Plasma total AGEs and pentosidine significantly and positively correlated to sterols accumulated in the atherosclerotic lesion, including cholesterol, desmosterol, campesterol, sitosterol, and oxysterols. On the other hand, sRAGE inversely correlated to total AGEs and pentosidine in plasma, and with major species of oxysterols, cholesterol, and markers of cholesterol synthesis and absorption in the atherosclerotic lesion. In multiple regression analyses, it was observed a significant inverse correlation between sRAGE and 24-hydroxycholesterol and desmosterol, and a positive significant correlation between pentosidine and 24-hydroxycholesterol, 27-hydroxycholesterol, and campesterol.In conclusion, the plasma concentration of AGEs and sRAGE is a tool to predict the accumulation of sterols in atherosclerotic lesions in symptomatic and asymptomatic individuals, helping to prevent and improve the management of acute cardiovascular complications.

Lipidome is lipids regulator in gastrointestinal tract and it is a life collar in COVID-19: A review

The term lipidome is mentioned to the total amount of the lipids inside the biological cells. The lipid enters the human gastrointestinal tract through external source and internal source. The absorption pathway of lipids in the gastrointestinal tract has many ways; the 1^st way, the lipid molecules are digested in the lumen before go through the enterocytes, digested products are re-esterified into complex lipid molecules. The 2^nd way, the intracellular lipids are accumulated into lipoproteins (chylomicrons) which transport lipids throughout the whole body. The lipids are re-synthesis again inside the human body where the gastrointestinal lipids are: (1) Transferred into the endoplasmic reticulum; (2) Collected as lipoproteins such as chylomicrons; or (3) Stored as lipid droplets in the cytosol. The lipids play an important role in many stages of the viral replication cycle. The specific lipid change occurs during viral infection in advanced viral replication cycle. There are 47 lipids within 11 lipid classes were significantly disturbed after viral infection. The virus connects with blood-borne lipoproteins and apolipoprotein E to change viral infectivity. The viral interest is cholesterol- and lipid raft-dependent molecules. In conclusion, lipidome is important in gastrointestinal fat absorption and coronavirus disease 2019 (COVID-19) infection so lipidome is basic in gut metabolism and in COVID-19 infection success.

It’s time to personalize and optimize lipid-lowering therapy

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Exploring the Lipidome: Current Lipid Extraction Techniques for Mass Spectrometry Analysis

In recent years, high-throughput lipid profiling has contributed to understand the biological, physiological and pathological roles of lipids in living organisms. Across all kingdoms of life, important cell and systemic processes are mediated by lipids including compartmentalization, signaling and energy homeostasis. Despite important advances in liquid chromatography and mass spectrometry, sample extraction procedures remain a bottleneck in lipidomic studies, since the wide structural diversity of lipids imposes a constrain in the type and amount of lipids extracted. Differences in extraction yield across lipid classes can induce a bias on down-stream analysis and outcomes. This review aims to summarize current lipid extraction techniques used for untargeted and targeted studies based on mass spectrometry. Considerations, applications, and limitations of these techniques are discussed when used to extract lipids in complex biological matrices, such as tissues, biofluids, foods, and microorganisms.

Oxysterols: From physiological tuners to pharmacological opportunities

Oxysterols are oxygenated forms of cholesterol generated via autooxidation by free radicals and ROS, or formed enzymically by a variety of enzymes such as those involved in the synthesis of bile acids. Although found at very low concentrations in vivo, these metabolites play key roles in health and disease, particularly in development and regulating immune cell responses, by binding to effector proteins such as LXRα, RORγ and Insig and directly or indirectly regulating transcriptional programmes that affect cell metabolism and function. In this review, we summarise the routes by which oxysterols can be generated and subsequently modified to other oxysterol metabolites and highlight their diverse and profound biological functions and opportunities to alter their levels using pharmacological approaches. LINKED ARTICLES: This article is part of a themed issue on Oxysterols, Lifelong Health and Therapeutics. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.16/issuetoc.