Purchase this article with an account.
T. Chan–Ling, T. Gardiner, L. Baxter, S. Hughes; Smooth Muscle Cell and Pericyte Changes Underly Pathogenesis of Plus Disease in Retinopathy of Prematurity (ROP) . Invest. Ophthalmol. Vis. Sci. 2006;47(13):3529.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Our aim was to determine whether alterations in mural cells, pericytes and smooth muscle cells (SMCs), are associated with the pathogenesis of ROP, including Plus Disease.
Kittens were exposed at postnatal day (P)1 to 60–70% oxygen for 4 days and returned to air for 0–27 days (hypoxic phase of kitten model of ROP). To more closely mimic human ROP, we modified the kitten model of ROP by subjecting P3 kittens to hyperoxia for only 2 days, resulting in delayed retinal vascularization and localised vessel loss rather than vaso–obliteration, then returned the kitten to air for 3 or 29 days. Retinas were double labelled with antibodies against desmin or alpha smooth muscle actin (SMA), and GS isolectin B4 to label mural cells and the vasculature respectively. The desmin ensheathment ratio (DER), a quantitative measure of vessel stability was determined.
Radial arterioles and venules of the neovasculature were dilated with reduced SMC coverage, and SMA and desmin immunohistochemistry (IHC) suggested that SMC differentiation was delayed and EM observations showed arteriolar SMC changes consistent with immaturity. In the surviving vasculature of the modified kitten model of ROP, venular SMA labelling was decreased, arteriolar SMA labelling less even, the difference between arterioles and venules at P3 using desmin IHC lost, and the DER of capillaries reduced.
The low DER of surviving vessels is consistent with an unstable vascular plexus. Our results provide compelling evidence of significant changes in arteriolar and venular SMCs in both experimental models of ROP. The delayed differentiation and apparent dedifferentiation of SMCs during the hypoxic phases could result in impaired ability to regulate blood flow, contributing to the vaso–dilatation and tortuosity, hallmarks of Plus disease. The dense vaso–proliferation observed could further compound the vessel dilatation and tortuosity observed due to its effect on venous return and vessel rheology.
This PDF is available to Subscribers Only