Obesity has become a major worldwide health problem. In every single country in the world, the incidence of obesity is rising continuously and therefore, the associated morbidity, mortality and both medical and economical costs are expected to increase as well. The majority of these complications are related to co-morbid conditions that include coronary artery disease, hypertension, type 2 diabetes mellitus, respiratory disorders and dyslipidemia. Obesity increases cardiovascular risk through risk factors such as increased fasting plasma triglycerides, high LDL cholesterol, low HDL cholesterol, elevated blood glucose and insulin levels and high blood pressure. Novel lipid dependent, metabolic risk factors associated to obesity are the presence of the small dense LDL phenotype, postprandial hyperlipidemia with accumulation of atherogenic remnants and hepatic overproduction of apoB containing lipoproteins. All these lipid abnormalities are typical features of the metabolic syndrome and may be associated to a pro-inflammatory gradient which in part may originate in the adipose tissue itself and directly affect the endothelium. An important link between obesity, the metabolic syndrome and dyslipidemia, seems to be the development of insulin resistance in peripheral tissues leading to an enhanced hepatic flux of fatty acids from dietary sources, intravascular lipolysis and from adipose tissue resistant to the antilipolytic effects of insulin. The current review will focus on these aspects of lipid metabolism in obesity and potential interventions to treat the obesity related dyslipidemia.
High alcohol intake remains harmful since it is associated with elevated plasma triglycerides, but also with cardiovascular disease, alcoholic fatty liver disease and the development of pancreatitis. Alcohol-induced hypertriglyceridemia is due to increased very-low-density lipoprotein secretion, impaired lipolysis and increased free fatty acid fluxes from adipose tissue to the liver. However, light to moderate alcohol consumption may be associated with decreased plasma triglycerides, probably determined by the type of alcoholic beverage consumed, genetic polymorphisms and lifestyle factors. Nevertheless, patients should be advised to reduce or stop alcohol consumption in case of hypertriglyceridemia.
Postprandial hyperlipidemia with accumulation of remnant lipoproteins is a common metabolic disturbance associated with atherosclerosis and vascular dysfunction, particularly during chronic disease states such as obesity, the metabolic syndrome and, diabetes. Remnant lipoproteins become attached to the vascular wall, where they can penetrate intact endothelium causing foam cell formation. Postprandial remnant lipoproteins can activate circulating leukocytes, upregulate the expression of endothelial adhesion molecules, facilitate adhesion and migration of inflammatory cells into the subendothelial space, and activate the complement system. Since humans are postprandial most of the day, the continuous generation of remnants after each meal may be one of the triggers for the development of atherosclerosis. Modulation of postprandial lipemia by lifestyle changes and pharmacological interventions could result in a further decrease of cardiovascular mortality and morbidity. This paper will provide an update on current concepts concerning the relationship between postprandial lipemia, inflammation, vascular function, and therapeutic options.
IntroductionErythrocytes carry apolipoprotein B on their membrane, but the determining factors of erythrocyte-bound apolipoprotein B (ery-apoB) are unknown. We aimed to explore the determinants of ery-apoB to gain more insight into potential mechanisms.MethodsSubjects with and without CVD were included (N = 398). Ery-apoB was measured on fresh whole blood samples using flow cytometry. Subjects with ery-apoB levels ≤0.20 a.u. were considered deficient. Carotid intima media thickness (CIMT) was determined as a measure of (subclinical) atherosclerosis.ResultsMean ery-apoB value was 23.2% lower in subjects with increased CIMT (0.80±0.09 mm, N = 140) compared to subjects with a normal CIMT (0.57±0.08 mm, N = 258) (P = 0.007, adjusted P<0.001). CIMT and ery-apoB were inversely correlated (Spearman’s r: –0.116, P = 0.021). A total of 55 subjects (13.6%) were considered ery-apoB deficient, which was associated with a medical history of CVD (OR: 1.86, 95% CI 1.04–3.33; adjusted OR: 1.55; 95% CI 0.85–2.82). Discontinuation of statins in 54 subjects did not influence ery-apoB values despite a 58.4% increase in serum apolipoprotein B. Subjects with blood group O had significantly higher ery-apoB values (1.56±0.94 a.u.) when compared to subjects with blood group A (0.89±1.15 a.u), blood group B (0.73±0.1.12 a.u.) or blood group AB (0.69±0.69 a.u.) (P-ANOVA = 0.002).ConclusionAbsence or very low values of ery-apoB are associated with clinical and subclinical atherosclerosis. While serum apolipoprotein B is not associated with ery-apoB, the ABO blood group seems to be a significant determinant.
Many risk factors have been identified as being responsible for the process of atherogenesis. Several of these risk factors are related to inflammation, which is an obligatory feature of the atherosclerotic plaque. Increasing evidence suggests that postprandial lipoproteins and glucose may be involved in the inflammatory process preceding the development of atherosclerosis. During the postprandial situation, remnants of chylomicrons and very low-density lipoproteins bind to circulating leukocytes and endothelial cells, leading to a state of acute activation with the expression of integrins on different cells, the generation of oxidative stress, production of cytokines and complement activation. Elevated plasma glucose levels may also induce leukocyte activation in humans. In addition, advanced glycation end products, formed during hyperglycemia, cause inflammation and endothelial damage. This chain of events results in a situation of acute inflammation causing endothelial dysfunction, which may be one of the earliest defects in atherogenesis. Interestingly, while this may occur several times each day after each meal, there is only limited information on the contribution of different nutrients on the postprandial inflammatory processes. In this review, we will focus on the available evidence and we will discuss the role of lifestyle and pharmaceutical interventions in modulating postprandial inflammation.
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