Lipid Triad: An Important Predictor of Dyslipidemia Related Disorders and its Therapeutic Intervention

Abstract

Cardiovascular disease (CVD) is leading cause of premature death worldwide. 30% of all global deaths in 2005, i.e. 17.5 million people died from this CVD. If proper and quick actions are not taken, an estimated number of 20 million people will die by 2015, including stroke [1]. Lavie et al. [2] stated regarding fiscal burden of CVD and, especially, coronary heart disease (CHD), most medical treatments are directed at the major CHD risk factors. CVD implies to any medical disorders related to heart and blood vessels. There are a number of known causative factors that are directly or indirectly responsible for CVD. The lipid triad refers basically to three lipid abnormalities: increased plasma triglycerides and small dense low density lipoprotein (sd-LDL), and decreased high density lipoprotein cholesterol (HDL-C) concentrations. Since lipid triad is highly atherogenic in nature causing CVD, also called as atherogenic lipoprotein phenotype. The liver secretes lipoproteins called very-low-density lipoproteins (VLDL) rich in triglycerides. As these lipoproteins come into contact with lipoprotein lipase situated on capillary endothelial cell, hydrolyzes the triglycerides leaving VLDL remnant. Many patients with premature CHD having cholesterol levels in the range of 200-240 mg/dl show other risk factors like hypertension, obesity or abnormalities in triglycerides metabolism. But these above anomalies are often seen in reduced concentration of HDL [3]. Low density lipoprotein cholesterol (LDL-C) rich in cholesterol has been extensively studied and known for its bad cholesterol because it is considered as a good marker for cardiovascular disease risk assessment [4] and its level in human body should be below 130 mg/dl. HDL-C ranging between 35-40 mg/dl is considered as good cholesterol as it helps in the removal of cholesterol along with it also shows antioxidant property carrying arylesterase/ paraoxonase antioxidant enzyme. High level about 60 mg/dl of HDL-C is believed to be played a good protective role in human health protection as it protects efficiently heart from dangerous attack on it. The various previous studies clearly indicate that high concentration of LDL-C and substantially increased ratio of LDL and HDL are important risk factors which promote atherosclerosis [5]. The study for UK Progression of Diabetes Study showed that LDL-C is the strongest risk factor for coronary heart disease followed by HDL-C in this population [6]. Thus it suggested that 0.1 mM rise in HDL-C would decrease coronary heart disease by 15%. LDL particles are differentiated into large buoyant LDL (lb-LDL) and small dense LDL (sd-LDL). These subfractions are associated with difference in size, density, physico-chemical composition, metabolic behavior and atherogenicity. Different known techniques such as density gradient, ultracentrifugation, polyacrylamide gel electrophoresis, nuclear magnetic resonance, etc. are employed for fractionation of LDL into sd-LDL and lb-LDL subfractions [7-9]. Lb-LDL particle shows >25.5 nm while sd-LDL particle shows ≤ 25.5 nm.