Purchase this article with an account.
Elisabeth Richert, Jan Tode, Alexa Klettner, Stefan Otto Johannes Koinzer, Ralf Brinkmann, Jost Hillenkamp, Ralph Lucius, Johann Roider; Reduction of Bruchs Membrane (BrM) Thickness after Pulsed Laser Irradiation in Apolipoprotein (Apo) E Knock Out Mice. Invest. Ophthalmol. Vis. Sci. 2017;58(8):1938.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
An increase of BrM thickness is one of the main characteristics of early non-exudative age related macular degeneration (dry AMD). Today there is no adequate treatment for dry AMD. We repetitively applied laser pulses in order to stimulate the retinal pigment epithelium (RPE) without thermal damage to the neuroretina. We investigated the effect of repetitive pulsed laser irradiation on BrM thickness in an AMD-mouse model.
One eye of five 9 month old ApoE knock out mice (B6.129P2-Apoetm1Unc/J) was treated with a pulsed 532 nm Nd:YAG laser (duration 250 ns, repetition rate 500 Hz, spot size 50 µm, mean energy 1.5 µJ, 150 pulses) while the fellow eye was used as intraindividual untreated control, as well as untreated age-matched C57BL/6J mice. We applied an average of 191 laser spots uniformly across the fundus with an interspot distance of 1 spot. Energy was chosen 70 % below clinical visibly threshold, titrated in the periphery. Eyes were investigated by fundus photography and optical coherence tomography (OCT) at the day of laser treatment and at the day of enucleation 1 month later. Thickness of BrM was measured by transmission electron microscopy (TEM) in a blinded standardized procedure.
In fundus photography and OCT, ApoE knock out mice showed AMD-associated degenerative changes such as drusen-like deposits, areas of hypopigmented RPE and a thickened BrM compared to control mice. Laser spots were not visible by fundus imaging or OCT at the day of laser treatment or 1 month later. In TEM we observed a significant reduction (p< 0.01) of BrM thickness in laser treated eyes (mean 534.2 nm, SEM 12.1 nm) compared to untreated fellow eyes (mean 574.0 nm, SEM 10.1 nm) 1 month after laser irradiation. The thickness of BrM in laser treated eyes was reduced to the level of C57BL/6J control mice (mean 537.7 nm, SEM 8.00 nm).
The repetitive pulsed laser irradiation reduced BrM thickness in ApoE knock out mice by RPE stimulation and rejuvenation without thermal damage to the neuroretina. This could improve flux across BrM. It might represent a possible treatment for early AMD.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
This PDF is available to Subscribers Only