Abstract
Purpose: :
Bruch’s membrane is an elastic lamina that provides a structural barrier between the underlying choriocapillaris and the RPE/subretinal space. Degradation of Bruch’s membrane and of the elastic component in particular are permissive for choroidal neovascularization. This study investigates the effect of heat treatment on human retinal pigment epithelial (RPE) cell production of elastin.
Methods: :
ARPE-19 cells, a line of human RPE cells, were cultured on transwells for 6 weeks. RPE differentiation was assessed by immunohistochemical examination of the tight junction markers ZO-1 and occludin. Differentiated ARPE-19 cells were incubated at 43°C for 90 min. At 1, 6, 24 and 48 hr post heat treatment, mRNA was isolated and levels of tropoelastin and fibrillin-1 were determined by real-time PCR (n=3) and on protein expression by western blot analysis.
Results: :
ARPE-19 cells cultured on transwells for 6 weeks displayed characteristic honey-comb patterning with ZO-1 and occludin localized at the intercellular junctions. Heat treatment stimulated a significant increase in tropoelastin mRNA that was maximal one hr following treatment compared to the control (p<0.05). There was no change in fibrillin-1 mRNA at any of the time points after heat treatment.
Conclusions: :
Human RPE cells have the potential for production of elastin, which can be further stimulated by incubation at elevated temperatures. These findings suggest that heat treatment may be used to induce regeneration of the elastin layer in the Bruch’s membrane, thus reducing the risk of chroidal neovascular invasion into the subretinal space.
Keywords: retinal pigment epithelium • extracellular matrix • regeneration