Effects of a single heparin bolus on neointimal growth after arterial injury in intact rabbits.
Heparinization is a routine procedure during angioplasty; however, its consequences on the late vascular response to a severe injury are unclear. The authors' objective was to explore the effect of a single heparin bolus at the time of a severe vascular injury on late intimal proliferation and neointimal thickening. The iliac artery of 57 normolipemic rabbits was overdistended with a balloon catheter. Heparin (250 IU/kg i.v.) was given to 29 rabbits ten minutes before angioplasty, whereas 28 rabbits served as untreated controls. Neointimal thickening was prominent at fourteen days after injury and reached near-maximal values at day 28. The intimal/medial area ratio was reduced by an average 28.3% with heparin (at day 28: 2.19 +/- 0.51 vs 1.57 +/- 0.59, control vs heparin, P = 0.02). Neointimal cells stained positively for HHF-35 antibody, directed against smooth muscle cell antigens. Neointimal proliferation, quantified through the number of cell nuclei peroxidase-stained for PCNA/cyclin antigen, was significantly decreased by 43% and 49% with heparin, respectively, at days 7 and 14 after injury. These data suggest that early exposure even to low doses of heparin accounts for much of its inhibitory effect in vascular response to injury; such an effect might prove important in interpreting results of human trials of interventions against restenosis.
Janiszewski
M
M
Heart Institute, Brazil.
Laurindo
F R
FR
Pasqualucci
C A
CA
da Luz
P L
PL
Pileggi
F
F
D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology*; D002404:Catheterization; D002455:Cell Division / Q000187:drug effects; D003251:Constriction, Pathologic / Q000517:prevention & control; D003864:Depression, Chemical; D006493:Heparin / Q000494:pharmacology*; D007083:Iliac Artery / Q000293:injuries*; D007124:Immunoenzyme Techniques; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects; D011817:Rabbits; D012008:Recurrence; D013997:Time Factors; D017539:Tunica Intima / Q000166:cytology / Q000187:drug effects*
D000925:Anticoagulants; D006493:Heparin