title: Protective effect of apolipoprotein A I, A II, C I and C II on endothelial cells injury induced by low density lipoprotein.
abstract: OBJECTIVE
  To investigate the protective effect of apo-lipoprotein (apo) A I, A II, C I and C II, the main proteins in high density lipoprotein (HDL), on the morphology and function of human umbilical vein endothelial cells injured with low density lipoprotein (LDL) in vitro.
  
  
  METHODS
  Cultured human endothelial cells derived from umbilical veins were exposed to LDL, HDL, and apoA I, A II, C I and C II. The morphology of endothelial cells was examined with phase contrast and transmission electron microscope. The released amount of lactate dehydrogenase (LDH) and 6-keto-prostaglandin F1 alpha (PGF1 alpha) was also measured.
  
  
  RESULTS
  Endothelial cells after being injured by LDL showed cell contraction, increased release of LDH and decreased secrection of prostacyclin (PGI2). However, the addition of HDL, and apoA I, A II, C I and C II before incubation with LDL inhibited the cellular injury induced by LDL as demonstrated by lowered LDH release, increased level of PGF1 alpha and prevention of morphological changes.
  
  
  CONCLUSIONS
  The results indicate that apoA I, A II, C I and C II, as well as HDL, may play an important role in combating atherogenesis by protecting endothelial cells from damages induced by LDL.
mesh_terms: D016632:Apolipoprotein A-I / Q000494:pharmacology*; D016633:Apolipoprotein A-II / Q000494:pharmacology; D053302:Apolipoprotein C-I; D053304:Apolipoprotein C-II; D001056:Apolipoproteins C / Q000494:pharmacology*; D016923:Cell Death; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D011464:Epoprostenol / Q000096:biosynthesis; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008075:Lipoproteins, HDL / Q000494:pharmacology; D008077:Lipoproteins, LDL; D014471:Umbilical Veins / Q000166:cytology