Lab

HDL Cholesterol

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HDL Cholesterol, High Density Lipoprotein, Lecithin Cholesterol Acyltransferase, LCAT

  • See Also
  1. Hyperlipidemia
  2. Lipoprotein
  • Physiology
  1. See Lipoprotein
  2. HDL is synthesized in the liver as empty, non-lipid bound Proteins (apolipoprotein A1), starting as the smallest and most dense Lipoproteins
  3. HDL is a Cholesterol scavenger returns excess Cholesterol and LDL remnants back to the liver, for bile synthesis
  4. HDL also transports apolipoproteins C2 and E to and from Triglyceride rich Lipoproteins
  5. Lecithin-Cholesterol acyl transferase (LCAT) enzyme is bound to HDL
    1. LCAT converts free Cholesterol into the more hydrophobic Cholesterol esters that are then sequestered into Lipoproteins
  • Interpretation
  1. Positive Cardiac Risk Factor (Atherogenic)
    1. HDL < 35
    2. Total Cholesterol to HDL ratio
      1. Men > 5.0
      2. Women > 4.5
  2. Negative Cardiac Risk Factor (Protective)
    1. HDL > 60
  • Increased
  1. Medications
    1. Gemfibrozil
    2. Niacin
    3. Exogenous Estrogens
  2. Moderate Alcohol intake (1 ounce per day)
  3. Regular aerobic Exercise
    1. Graded increase with miles run per week
    2. Kokkinos (1995) Arch Intern Med 155(4):415-20 [PubMed]
  4. Weight loss (for obese patients)
    1. HDL increases 2 mg/dl for each 4.5 kg of weight loss
  • Decreased
  1. Tobacco Abuse
  2. Diabetes Mellitus
  3. Hypertriglyceridemia
  4. Menopause
  5. Obesity
  6. Puberty in males
  7. Uremia
  8. Anabolic Steroids
  9. Apolipoprotein deficiency
  10. Liver disease
  11. Tangier disease
  12. Medications
    1. Progestins
    2. Probucol
  • References
  1. Ginsberg (2000) Am J Cardiol 86(suppl):41L-45L [PubMed]