CORONARY ARTERY BYPASS GRAFTING PATIENTS: GLYCEROPHOSPHOLIPIDS PROFILE, GENES EXPRESSION AND INFLAMMATORY STATUS STUDY

Cardiovascular Diseases (CVDs) are a group of disorders of the heart and blood vessels including both diseases of the blood vessels supplying the heart muscle (coronary heart disease) and damages of heart muscle and valves due to different factors, such as streptococcal bacteria which cause rheumatic heart disease. Build-up of fat deposits on the inner walls of the blood vessels (atherosclerotic plaques) that supply the heart is one of the main factor of coronary heart disease. Atherosclerosis is a well known inflammatory condition in which the artery wall thickens due to the accumulation of fatty materials, mainly cholesterol, caused by the accumulation of macrophage white blood cells and promoted by low-density lipoproteins. Various anatomic, physiological and behavioral risk factors for atherosclerosis, such as obesity, are known. Body fat is stored in various depots; fat stored subcutaneously reach around 85% of total and the remaining 10% is stored in the viscera area. Fat is also localized in other different depots and is known as pericardial, epicardial, intracellular, buccal and ectopic fat. It has been recognized that the correlation between CVDs and increased body weight/obesity is more linked to body fat distribution rather than to the total amount of body fat. Epicardial adipose tissue (EAT) might function as a lipid-storing depot, as an endocrine organ secreting hormones and as an inflammatory tissue secreting cytokines and chemokines. Due to its proximity to the adventitia of the coronary arteries and myocardium it is possible that it could play a role in the pathogenesis of coronary atherosclerosis (CAD). During era of genomic, trascriptomics, metabolomics, lipidomics, lipids composition is highly studied to better understand the lipid molecular profile in different diseases. Goal of our study is monitoring lipid alteration in biological samples obtained from CAD patients to better understand lipid involvement in cardiovascular disease and found potential biomarkers involved in this pathology. Patients who underwent coronary artery bypass grafting (CABG) showed a decrease concentration in polyunsaturated fatty acids (PUFA) compared to patients undergoing valvular replacement and utilized as negative-CAD controls. PUFA/saturated fatty acid (SFA) ratio was statistically lower in CABG patient compared to valvular patients. Percentage of oleic acid (18:1) was higher in CABG compared to valvular replacement patients while percentage of linoleic (18:2) was lower. No significant differences have been observed relative to other lipids between CABG and valvular patients. Lipid analysis was quantified by electrospray ionization tandem mass spectrometry (ESI-MS/MS) in positive ion mod. Glycerophospholipid analysis revealed lower levels of phosphatidylethanolamine (PE), phosphatidylcholine (PC) and phosphatidylserine (PS) in CABG patients compared to valvular patients. Lower statistically significant lipid concentration was visible in CABG compared to valvular for PC species, such as PC 36:2, 34:3, 36:3, 36:4, 38:4, 40:4, 36:5, 38:5, 38:6 and 40:6. Similarly lipid composition for PE species was for PE 34:1, 36:1, 36:2, 36:3, 36:4, 38:4, 40:4, 38:5, 40:5 and 40:6 statistically lower in CABG compared to valvular. While for PS class only one lipid specie, PS 36:1 was statistically lower in CABG compared to valvular. Epicardial tissue lipid species analysis, also after subdivision for BMI, waist, waist-to-hip ratio (WHR), showed a decrease of lipid classes of PC, PE and PS in CABG patients compared to valvular patient. Obesity is a pre-disease condition that induces pathological angiogenesis and impaired vascular functions. These changes lead to the outset, development and progression of many diseases such as, cancer, CVD, diabetic complication and chronic inflammation. Transcriptomic data from epicardial tissue, showed an up- or down-regulation of genes involved in angiogenesis, both pro- and anti-genetic, such as matrix metalloproteinase 2 and 9 (MMP-2 and MMP-9), vascular endothelial growth factor (VEGF), fibroblast growth factors (FGF), angiogenin (ANG) and tissue inhibitor of metalloproteinases (TIMP). MMP-2 and MMP-9 were highly expressed in CABG compared to valvular (129 and 73 folds respectively). The same was observed for hepatocyte growth factor (HGF), VEGFA, FGF-2, hypoxia-inducible factors-1 (HIF-1) and TIMP-1. For these genes fold increase values were 170.55, 34.25, 28, 46.3, and 138.74 respectively. Otherwise, ANG and endostatin (COL18A-1) genes had lower expression in CABG compared to valvular (-13.41 and -5.2 folds respectively). Trascriptomic data showed, for gene involved in adipocyte differentiation, that peroxisome proliferator-activated receptor gamma (PPAR gamma; -5.8 folds ), delta-like 1 homolog (DLK; -36.08 folds), adiponectin (adipoQ; -19.19 folds), activin A receptor, type I (ACVR1; -45.37 folds), fatty acid binding protein 4 (FABP4; -33.58 folds), cytoplasmic polyadenylation element binding protein 1 (CEBP; -25.20 folds), lipin 1 (LPIN1; -42,94 folds), lipoprotein lipase (LPL; -18.86 folds) and phosphoenolpyruvate carboxykinase 1 (PCK1; -44.95) were down regulate in CABG compared to valvular. While leptin (LEP; 27 folds), GATA binding protein 2 (7.7 folds), GATA binding protein 3 (75 folds) uncoupling protein (UCP-1; 112.05, UCP-2; 246.35 and UCP-3; 43.29 folds), complement factor D preproprotein (CFD; 47.88 folds), proteoglycan 4 (PRG4; 142.26 folds), solute carrier family 2 (facilitated glucose transporter), member 4 (SLC2a4; -22.24 folds), Glyceraldehyde 3 phosphate dehydrogenase 1 (GAPDH; 46.44 folds), resistin (RETN; 152.36 folds) and mesoderm specific transcript homolog (MEST; 71.77 folds) were highly expressed in CABG compared to valvular. A great increase in the expression of all of the genes evaluated was observed in CABG compared to valvular patients. Decrease in PC species and reductions in percentage of PUFA are associated whit CVDs, a down or up expression of studied genes also are connected with heart disease. Our data therefore emphasize a possible greater involvement of lipids in patients with CABG compared to valvular patients.