Early morphogenesis of persistent hyperplastic tunica vasculosa lentis and primary vitreous (PHTVL/PHPV)

Abstract

This study provides scanning electron microscopic observations on the early morphogenesis of persistent hyperplastic tunica vasculosa lentis and primary vitreous (PHTVL/PHPV) in canine fetuses at days 28 35 postcoitum (D28 and D35). From previous studies regarding PHTVL/PHPV it is known that a retrolental plaque of fibrovascular tissue is present in eyes of affected canine fetuses from the D33 stage. The contribution of vitreous cells to the formation of the plaque is supported by the results of this study. The lens capsules at the stages described were not found to contain abnormalities such as transparent (thinner) parts or rents, as have been described for postnatal cases of PHTVL/PHPV. These findings support the hypothesis that the capsular anomalies observed in postnatal patients are secondary entities.

Persistent fetal intraocular vasculature in the European ferret (Mustela putorius): clinical and histological aspects

“…To simplify the clinical description of PFIV in the Doberman pinscher, a classification scheme consisting of 6 grades of magnitude has been proposed 6 . Persistence of fetal intraocular vasculature detected in ferrets of this report appear similar to reports in both humans and certain canine breeds 1 , 5 –11 . As clinical signs vary among eyes with PFIV in ferrets, overlap of abnormalities among different classifications frequently occurs.…”

“…Most cases of PFIV have no known cause, are unilateral, and are considered isolated, sporadic, congenital vascular malformations within the eye. Aside from reports of isolated PFIV in the horse, 2 rabbit, 3 and rodent, 3 several hereditary forms of PFIV have been reported in humans and dogs 1 –12 . An autosomal dominant mode of inheritance with incomplete penetrance has been proposed for PFIV in the Doberman pinscher and Staffordshire bull terrier breeds 6 –8…”

High frequency of persistent hyperplastic primary vitreous and cataracts in p53-deficient mice

“…In the former breed, initial over-development as well as subsequent incomplete regression of primary vitreous is seen (Boeve et al, 1988). Retinal glial elements such as Mueller cells and fibrous astrocytes as well as vitreous cells contribute to the formation of PHTVL (Boeve et al, 1990;. We did not observe any over-development of the primary vitreous in the p53 7/7 mice: at the earliest time points the amount of vasculature is very similar to that of the wild-type control.…”

“…PHPV has also been described in some dog breeds: originally in the Doberman pinscher and later in the Staffordshire bull terrier (Stades, 1980;Curtis et al, 1984). In the former breed, initial over-development as well as subsequent incomplete regression of primary vitreous is seen (Boeve et al, 1988). Retinal glial elements such as Mueller cells and fibrous astrocytes as well as vitreous cells contribute to the formation of PHTVL (Boeve et al, 1990;.…”

“…Several light and electron microscopic studies have catalogued the early morphology and/or regression of the primary vitreous in the human eye (Sellheyer and Spitznas, 1987), as well as in other animals including the rat (Hollenberg and Dickson, 1971;Cairns, 1959;Latker, 1981), the rabbit (Jack, 1972;Gloor, 1973b) and the dog (Boeve et al, 1988). Gloor was the first to describe the development of the mouse vitreous (Gloor, 1973a).…”