Basic Concept of Lipids PDF

Dr Norsyahida Mohd Fauzi Basic Concept of Lipid Lecturer in Biopharmacy and Pharmacology Discipline, Member of Drug and Herbal Research Centre  Digestion and absorption of...

Dr Norsyahida Mohd Fauzi Basic Concept of Lipid Lecturer in Biopharmacy and Pharmacology Discipline, Member of Drug and Herbal Research Centre  Digestion and absorption of lipid Structure of lipids Lipoprotein particles as a carrier.  Digestion Produces bile salt Pancreatic lipase for TG degradation. It is released following stimulation stores bile by cholecystokinin salt Cholesterol Bile salt esterase for form chelesteryl ester miscelles degradation. Phospholipase A2 for phospholipid degradation Absorption and resynthesis of TG Lipid s Why do we need TG? Cellular energy Source of ATP Adipocytes has high capacity to store TG.  Why do we need cholesterol? Membrane stiffener Precursors for : - Steroid hormones - Synthesis of Vitamin D - Bile acids.  Lipid malabsorption can cause malnutrition Can be due to disturbances in: - Lipid digestion - Lipid absorption Can be caused by several factors : - Cistic fibrosis (poor digestion-↓pancreatic enzyme) - Shortened bowel (decreased absorption) Lipid is carried in blood by a ‘carrier’ Types of lipoprotein particle  Lipid transport Bil e excretio n Risk factors for cardiovascular disease Elevated LDL Reduced HDL Elevated lipoprotein (a) Chylomicrons carry dietary TG to tissues and CE to liver VLDL carry TG from liver to peripheral tissues. LDL carries cholesterol to peripheral tissues HDL carries cholesterol to liver Reverse cholesterol transport involves: efflux of cholesterol from peripheral cells to HDL esterification of cholesterol by LCAT, binding of the cholesteryl ester–rich HDL (HDL2) to liver and steroidogenic cells the selective transfer of the cholesteryl esters into these cells release of lipid-depleted HDL (HDL3). The efflux of cholesterol from peripheral cells is mediated, at least in part, by the transport protein, ABCA1. The uptake of cholesteryl esters by the liver is mediated by a cell- surface receptor. SR-B1 (scavenger receptor class B type 1) that binds HDL Consequences of dyslipidemia