title: [Homocysteine' s effect on tPA and PAI-1 gene expression in HUVEC].
abstract: OBJECTIVE
  In order to elucidate the relationship between homocysteine (Hcy) and the fibrinolytic system, we examined the effect of Hcy on tissue- type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) gene expression in human umbilical vein endothelial cells (HUVEC) in vitro.
  
  
  METHODS
  Total RNA was extracted from HUVEC exposed to physical and pathological concentrations of Hcy (0, 10, 50, 200, 500 micromol/L ) for 24 hours, using the guanidinium isothiocyanate method. The semi-quantification of tPA and PAI-1 mRNA in HUVEC was carried out by reverse transcriptase-polymerase chain reaction (RT-PCR).
  
  
  RESULTS
  PAI-1 mRNA levels was enhanced by Hcy at concentrations of 500 micromol/L of Hcy, compared with that of 0 micromol/L Hcy (P < 0.05). The mRNA expression of tPA, however, was significantly decreased at concentrations of 500 micromol/L Hcy, compared with that of 10 micromol/L Hcy (P < 0.05), but compared with the control group, the tPA level of 10 micromol/L Hcy was much higher (P < 0.05).
  
  
  CONCLUSIONS
  Hyperhomocysteinemia increases the incidence of cardio cerebral vascular disease, which may be caused by decreasing the activity of fibrinolytic system, whereas, the physiological concentration of Hcy may be decreased the incidence by enhancing the activity of fibrinolytic system.
authors.affiliation: Cardiology Department, the First Affiliated Hospital of Harbin Medical University, Harbin 150001, China.
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Zhou
authors.forename: Yi-Fang
authors.initials: YF
authors.lastname: Mei
authors.forename: Lan-Feng
authors.initials: LF
authors.lastname: Wang
authors.forename: Hong
authors.initials: H
authors.lastname: Jin
authors.forename: Shao-Jun
authors.initials: SJ
authors.lastname: Li
authors.forename: Xue-Song
authors.initials: XS
authors.lastname: Yin
authors.forename: Wei-Min
authors.initials: WM
authors.lastname: Li
mesh_terms: D002478:Cells, Cultured; D015870:Gene Expression; D006710:Homocysteine / Q000008:administration & dosage / Q000494:pharmacology*; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D010959:Tissue Plasminogen Activator / Q000235:genetics / Q000378:metabolism*
chemical_list: D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; C051321:SERPINE1 protein, human; D006710:Homocysteine; D010959:Tissue Plasminogen Activator