LIPIDS

• Triglycerides consist of three fatty acids attached to one glycerol molecule by an ester linkage.
• Apo A-I: LCAT Activator
• APO B-100: LDL-R Ligand
• HDL

  • Lipoprotein that contains the greatest amount of protein
• APO C-II: LPL cofactor
• APO A-1 is found on HDL
• APO B-100 is found on VLDL, IDL, and LDL
• APO B-48 is found on Chylomicrons
• Density and Electrophoretic Pattern

  A) Chylomicron

  B) VLDL

  C) IDL

  D) LDL

  E) HDL

  F) Chylomicron

  G) LDL

  H) IDL

  I) VLDL

  J) HDL

  
• Electrophoretic Pattern of Lipoprotein

  • HDL: Alpha
  • Chylomicron: Origin
  • IDL: Broad beta
  • VLDL: Pre beta
  • LDL: Beta
• Chylomicron transports exogenous triglycerides while VLDL transports endogenous triglycerides
• IDL

  • Lipolytic product of VLDL catabolism taken up by the liver or converted to LDL
• B-VLDL

  • High cholesterol content seen in type 3 hyperlipoproteinemia or familial dysbetalipoproteinemia
  • A.k.a Floating Beta Lipoprotein
• Lp(a)

  • Has a prothrombotic lipoprotein homologous to plasminogen; associated with stroke, MI and CHD
  • A.k.a Sinking Pre-beta Lipoprotein
• LpX

  • Associated with obstructive jaundice and LCAT deficiency
• FREDRICK CLASSIFICATION OF HYPERLIPOPROTEINEMIA

  A) Chylomicronemia

  B) CM

  C) TG

  D) Hypercholesterolemia

  E) LDL

  F) TC

  G) Combined hyperlipidemia

  H) VLDL, LDL

  I) Dysbetalipoproteinemia

  J) IDL

  K) Hypertriglyceridemia

  L) VLDL

  M) TG

  N) Mixed Hyperlipidemia

  O) VLDL, CM

  
• Tangier Disease

  • Characterized by low to undetectable HDL due to a mutation in the ABCA1 gene
• Tay-Sach's Disease

  • Accumulation of sphingolipid due to the deficiency of hexosaminidase A
• Abetalipoproteinemia

  • Absence of Apo-B containing lipoproteins due to the mutation of MTTP gene
  • A.k.a Bassen-Kornzweig Syndrome
• Cholesterol and Triglyceride Reference Method: GCMS
• Colorimetric Results

  Liebermann Burchardt: Green

  Salkowski: Red
• Saponification

  Reagent: Alcoholic KOH

  Purpose: Hydrolysis of cholesterol esters
• Extraction

  Reagent: Bloor's Reagent (Ethanol-ether)

  Purpose: Removal of protein interference
• HDL

  • Involved in reverse cholesterol transport
• Cholesterol Reference Values

  • Desirable: <200 mg/dL
  • Borderline High: 200-239 mg/dL
  • High: ≥240 mg/dL
• Plasma Appearance

  Clear: <200 mg/dL

  Turbid: ≥300 mg/dL

  Opaque and Milky: ≥600 mg/dL
• Reference Method for HDL

  • Ultracentrifugation
• Purification

  • Reagent: Digitonin
  • Purpose: Precipitation of free cholesterol
• Heparin-manganese: Most common precipitating agent in HDL determination