Ultrastructural changes in a murine model of graded Bruch membrane lipoidal degeneration and corresponding VEGF164 detection. Invest Ophthalmol Vis Sci

PURPOSE. To evaluate ultrastructural changes in low-density lipoprotein (LDL) receptor knockout (R Ϫ/Ϫ ) mice consuming different diets as a potential model of Bruch membrane (BM) lipoidal degeneration and to determine the distribution and concentration of VEGF 164 in this mouse model. METHODS. Eight-month-old LDL-R Ϫ/Ϫ mice and wild-type controls were fed a standard or a high-fat diet. Animals were killed, and plasma cholesterol levels were determined. Using transmission electron microscopy, BM thickness, lipid vacuole size, and retinal pigment epithelial height were measured. Degenerative alterations of choriocapillaris, RPE, and photoreceptors were described and graded. Using light microscopy, VEGF 164 immunohistoreactivity was graded. Neutral lipids were detected with oil red O. RESULTS. Choriocapillaris, BM, RPE, and photoreceptors of standard diet control animals showed a regular architecture. LDL-R Ϫ/Ϫ mice fed a standard diet showed more diffuse focal alterations than control mice fed a high-fat diet. Within the choriocapillaris, the basement membrane was thickened, endothelial fenestration numbers were reduced, and lumina narrowed. BM thickness increased with a loss of regular structure. With pronounced BM degeneration, lipid inclusions increased in number and size. A decrease in retinal pigment epithelial cell height was accompanied by signs of intracellular degeneration. Photoreceptor outer segments showed focal degeneration and the formation of vacuoles. All these changes were most pronounced in LDL-R Ϫ/Ϫ mice after a high-fat diet. 1,2 BM is a thin, five-layer connective tissue between the metabolically active RPE and the choriocapillaris that provides the RPE and the outer retina with nutrients. Its central position shows how essential this structure is for the maintenance and health in adjacent tissues. With age, the human BM undergoes distinct, well-established changes thought to compromise metabolic transport through it. 1 Human BM thickness increases significantly with age, and structural degeneration of the elastic and collagenous layers also increases. 3-5 Simultaneous with these changes, neutral lipids accumulate in BM

Further Investigation of the Tolerance and Mechanical Adjustability of the *Acri.Tec AR-1 PC/IOL in Rabbit Eyes: An Intraocular Lens with Reversibly Adjustable Optical Power

Purpose: To examine the tolerance and mechanical function of an adjustable intraocular lens (IOL) in rabbit eyes. Methods: Implantation of the * Acri.Tec AR-1 PC/IOL into 14 rabbit eyes. Manipulation of the lens 8 weeks after implantation in order to change the refractive power. Follow-up for up to 5 months. Histopathologic examination of the eyes. Results: Implantation and mechanical adjustment of the PC/IOL were possible. Eyes healed normally. No difference between eyes containing the * Acri.Tec AR-1 PC/IOL and eyes containing the control PC/IOL could be detected with respect to signs of inflammatory reaction, corneal transparency, intraocular pressure and histopathologic appearance. Histopathologic examination of the eyes showed that the * Acri.Tec AR-1 PC/ IOL did not cause any damage in rabbit eyes. Conclusion: The * Acri.Tec AR-1 PC/IOL is well tolerated in rabbit eyes for extended periods of time, suggesting that this PC/IOL should be well tolerated in the long run. Surgical adjustment of the adjusting element can be performed with little effort several weeks after implantation