Endothelial cell-stimulating angiogenesis factor in vitreous from extraretinal neovascularizations.

The presence of endothelial cell-stimulating angiogenic factor (ESAF) in diseased human vitreous humour has been established. The molecular mass and chromatographic behavior of this material and its property of activating procollagenase indicate it to be identical to the ESAF isolated from other sources. The biological activity of ESAF from human vitreous was demonstrated by its ability to induce positive responses in the rabbit corneal pocket, and in the chick chorioallantoic membrane and yolk sac membrane tests.

The effect of cryotherapy on oxygen-induced retinopathy in the newborn kitten.

Partial cryotherapy was performed in the right eye of 14 kittens with experimental oxygen-induced retinopathy, while the left eye remained untreated as a control. Subsequent funduscopic examination and histopathological studies of all kittens showed no significant difference between the treated and untreated eyes with respect to the amount of neovascular proliferation. We attribute this negative result mainly to the fact that the cryoablation of the kittens' retina was incomplete, leaving a considerable amount of residual ischemic retina.

Increased procollagenase activating angiogenic factor in the vitreous humour of oxygen treated kittens.

Previous studies have demonstrated an increase in a low molecular weight angiogenic factor (ESAF) present in the retinae of kittens with oxygen induced retinopathy. The present paper describes differences in the quantity of ESAF extracted from the vitreous humour of control and oxygen treated animals and proposes a mechanism for the induction of intravitreal neovascularisation.

Oxygen-induced retinopathy in newborn kittens. A model for ischemic vasoproliferative retinopathy.

Fourteen kittens were reared in 80% oxygen for 65-72 hr, after which they were returned to room air. At that time, funduscopic examination of all the kittens showed complete obliteration of the retinal vasculature and even optic disc vessels. In the following 18-21 days, florid preretinal new vessels were found growing into the vitreous from the revascularized retina and from the optic disc itself.

Effect of oxygen tension on the quantities of procollagenase-activating angiogenic factor present in the developing kitten retina.

Maintenance of newborn kittens in an oxygen rich atmosphere followed by a recovery period in a normal atmosphere mimicked the effects of the human disease retrolental fibroplasia. The retinas of such kittens contained significantly raised levels of low molecular weight angiogenic material (as measured by procollagenase activation) when compared with those of a control group of kittens.