The
vitronectin receptor (alphavbeta3) mediates several biological processes that are critical to the formation of a
neointima after coronary interventions. Blockade of alphavbeta3 could reduce
neointima formation by inhibiting smooth muscle cell migration, decreasing
transforming growth factor-beta1 expression, enhancing apoptosis, or reducing neovasculature. The effects of short-term administration of
Vitaxin, a humanized
monoclonal antibody to alphavbeta3, on the responses to balloon injury were tested in hyperlipidemic rabbits. Balloon angioplasty was performed on the iliac arteries of male New Zealand White rabbits that were fed an atherogenic diet for 1 week before injury and until euthanization at 4 weeks. Rabbits were given either saline (control) or 1 of 2 dosing regimens of
Vitaxin (high dose, 5.0 mg/kg, and low dose, 0.5 mg/kg), which were administered intra-arterially before injury and intramuscularly on days 2 and 3. High-dose and low-dose
Vitaxin were equally effective in decreasing
neointima formation even in the presence of
hypercholesterolemia, a stimulus to alphavbeta3 expression.
Vitaxin reduced
transforming growth factor-beta1 and enhanced apoptosis in injured arteries. Despite these positive effects,
Vitaxin administration was associated with a reduction in artery size, indicating a negative effect on remodeling.
Vitaxin has a potential role in preventing intimal
hyperplasia, especially if the negative effects on remodeling can be overcome, by dose adjustment or other strategies.