Plasminogen activator and plasminogen activator inhibitor gene expression in human saphenous vein organ culture.
We describe the expression of tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI-1) in saphenous vein culture. Smooth muscle cells (SMC) are quiescent in fresh tissue, whereas these cells acquire a proliferating phenotype when venous segments are cultured in the presence of serum. t-PA and PAI-1 were localized immunohistochemically and quantified using biochemical techniques. t-PA and PAI-1 mRNA was quantified by reverse transcription polymerase chain reaction (RT--PCR) assay. Immunostaining showed an increase in the positivity of proliferating cell nuclear antigen (PCNA) from 10-day tissue culture. Tissue sections from fresh vein showed minimal t-PA and maximal PAI-1 immunostaining. In contrast, 10-day cultures showed an increase in t-PA and a decline in PAI-1 staining. Biochemical analysis revealed a 118% increase in t-PA and a 50% decrease in PAI-1 antigen levels from 10-day tissue cultures. RT--PCR demonstrated that the mRNA encoding t-PA increased, while PAI-1 decreased after 10 days of culture. In conclusion, venous culture showed an up-regulation of t-PA and a repression of PAI-1 gene expression during SMC proliferation in the vessel wall. The PAI-1 repression observed in venous culture is in contrast to the situation observed in human atheroma. A shift in the t-PA/PAI-1 balance may have a role in vascular remodeling.
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Division of Cardiology, Department of Medicine, Clinical Sciences Wing, Glenfield Hospital, Groby Road, Leicester LE3 9QP, United Kingdom.
Swanson
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Warner
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Gershlick
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AH
de Bono
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DP
D015153:Blotting, Western; D018076:DNA, Complementary / Q000737:chemistry; D004730:Endothelium, Vascular / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005786:Gene Expression Regulation; D006801:Humans; D009924:Organ Culture Techniques; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics*; D010960:Plasminogen Activators / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012501:Saphenous Vein / Q000378:metabolism*
D018076:DNA, Complementary; D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D010960:Plasminogen Activators