Angiogenic activity of leptin in the chick embryo chorioallantoic membraneis in part mediated by endogenous fibroblast growth factor-2

Recently, it has been demonstrated that leptin, the product of the ob gene, playing a key role in the regulation of body weight, is angiogenic in vitr o and in vivo. In this study we investigated the angiogenic potential of hu man leptin in vivo by using the chick embryo chorioallantoic membrane (CAM) assay, with the aim to establish whether this angiogenic activity is partl y dependent on endogenous fibroblast growth factor-2 (FGF-2), which is norm ally expressed during CAM development. Results showed that leptin is able t o stimulate angiogenesis and that the angiogenic response is similar to tha t obtained with FGF-2. The stimulating property of leptin is specific, as t he application of anti-leptin antibodies onto the CAM significantly inhibit s the angiogenic response. Moreover, this angiogenic activity is in part du e to the activation of endogenous FGF-2. The application of anti-FGF-2 anti bodies reduces the angiogenic response to leptin by 40%. Our study confirms that leptin is angiogenic in vivo and suggests that, at least in the chick CAM, its activity is in part mediated by the activation of endogenous FGF- 2.