Macular Degeneration: Fauser S

Fauser S, Krohne TU, Kirchhof B, Joussen AM. · Abteilung für Netzhaut- und Glaskörperchirurgie des Zentrums für Augenheilkunde und Zentrum für Molekulare Medizin, Universität zu Köln. · Klin Monatsbl Augenheilkd. · Pubmed #12953154 No free full text.

Abstract: The current clinical classification into focal, diffuse, and ischaemic maculopathy is useful with respect to pathomechanism and therapy. This review discusses the value of standard therapeutical options as well as the recent surgical and pharmacological approaches.

Krohne TU, Fauser S, Kirchhof B, Joussen AM. · Abteilung für Netzhaut- und Glaskörperchirurgie des Zentrums für Augenheilkunde und Zentrum für Molekulare Medizin, Universität zu Köln, Germany. · Klin Monatsbl Augenheilkd. · Pubmed #12953153 No free full text.

Abstract: Hyperglycaemia causes breakdown of the blood retina barrier leading to formation of macular oedema and consecutive visual loss. Three major mechanisms are involved in barrier breakdown: increased paracellular permeability of vascular endothelium due to disruption of cell junctions, loss of endothelial cell layer integrity due to cell destruction, and increased transcellular transport through the endothelium. This review focuses on the molecular basis of these mechanisms and discusses the role of cytokines and cellular interactions in blood retina barrier breakdown.

Fauser S, Engelmann K, Krohne TU, Lappas A, Kirchhof B, Joussen AM. · Abteilung für Netzhaut- und Glaskörperchirurgie und Zentrum für Molekulare Medizin, Universität zu Köln, Cologne. · Ophthalmologe. · Pubmed #12682762 No free full text.

Abstract: Age-related macular degeneration (AMD) is the leading cause of blindness in the developed world but the pathogenesis remains poorly understood.Malfunction of the retinal pigment epithelium (RPE) plays a central role in the disease and leads to either choriodal atrophy or proliferation.This article reviews the current concepts of the development of choriodal atrophy and neovascularisation. Furthermore, available animal models and potential therapeutical targets are discussed.

Semkova I, Fauser S, Lappas A, Smyth N, Kociok N, Kirchhof B, Paulsson M, Poulaki V, Joussen AM. · Department of Vitreoretinal Surgery, Center for Ophthalmology, University of Cologne, Cologne, Germany. · FASEB J. · Pubmed #16807368 links to  free full text

Abstract: Choroidal neovascularization (CNV) is responsible for the severe visual loss in age-related macular degeneration. CNV formation is considered to be due to an imbalance between pro- and antiangiogenic factors that lead to neovascular growth from the choriocapillaris into the subretinal space. To define whether FasL overexpression in retinal pigment epithelial cells (RPE) can inhibit choroidal neovascularization through Fas-FasL-mediated apoptosis, we examined the role of this pathway in a mouse model of laser-induced choroidal neovascularization. FasL was expressed in the retinal pigment epithelium of transgenic mice. Polymerase chain reaction (PCR), immunoblot, and immunohistochemistry confirmed that the transgene FasL was specifically expressed in RPE. The established laser model was used to induce choroidal neovascularization (CNV) in wild-type (WT) and transgenic mice. CNV formation was compared with respect to fluorescein angiographic leakage (at days 0 and 14 after laser injury) and histological appearance. The lesions were assessed on RPE-choroidal flatmounts after CD31-labeling and with confocal microscopy after perfusion with rhodamine-labeled concanavalin A (Con A). Apoptosis was quantified by TUNEL positivity and caspase activation. FasL mRNA and protein were highly expressed in the RPE of the transgenic mice before and after laser photocoagulation. In contrast, FasL was only weakly expressed in the RPE layer of WT C57BL/6J mice. While ruptures of Bruch's membrane and CNV formation were observed histologically two weeks after laser photocoagulation in transgenic as well as control eyes, the shape and size of CNV lesions were reduced in the transgenic mice. The area of leakage was decreased by 70% in FasL transgenic mice compared with WT mice (P<0.005). The number of TUNEL-positive cells was greater in FasL-overexpressing mice and correlated with the expression of activated caspases. Th expression of other antiangiogenic factors such as PEDF remained unchanged. The specific overexpression of FasL in RPE layer reduced CNV formation in our laser model. Our results strongly point to the FasL-Fas pathway as a potential therapeutic target in controlling pathological choroidal neovascularization.

Radetzky S, Walter P, Fauser S, Koizumi K, Kirchhof B, Joussen AM. · Department of Vitreoretinal Surgery, Center for Ophthalmology, Joseph Stelzmann-Strasse 9, 50931, Cologne, Germany. · Graefes Arch Clin Exp Ophthalmol. · Pubmed #15042375 No free full text.

Abstract: PURPOSE: To evaluate the efficacy of inner limiting membrane (ILM) peeling in persistent macular edema. METHODS: This retrospective review analyzed a series of 23 eyes from 23 patients with persistent macular edema treated by pars plana vitrectomy (PPV) with indocyanine green (ICG)-assisted peeling of the ILM. Thirteen female and 10 male patients with a mean age of 57.2+/-15.6 (24-77) years underwent operation between May 2000 and October 2001. The main diagnoses were uveitis (anterior, intermediate, posterior and panuveitis) ( n=9), central retinal vein occlusion (CRVO) (n=4), diabetic retinopathy (DR) ( n=5), vitreoretinal traction syndrome ( n=2), and Irvine-Gass syndrome ( n=3). Nine eyes had undergone phacoemulsification (PE) previously and two eyes had been subjected to combined PE and ILM peeling. The eyes were tamponaded with gas (3), silicone oil (5) or air (11). In four cases no endotamponade was used. Improvement in visual acuity of 2 lines or more was regarded as significant. RESULTS: Visual acuity improved after 3 months in 9 of the 23 patients. After 6 months and at the follow-up, a significant improvement was found in 6/21 and 7/21 patients. This improvement was predominantly seen in patients with uveitis (5/9), or diabetic maculopathy (3/5); One patient with Irvine-Gass syndrome showed a significant reduction, one with vitreoretinal traction an improvement in visual acuity. The group of patients with CRVO showed no significant change during the follow-up. The choice of endotamponade did not alter the visual acuity outcome. CONCLUSIONS: Different patient groups respond differently to ILM peeling. Although overall significant visual acuity improvement was observed in only one third of all cases 12 months after ILM peeling for persistent macular edema, patients with uveitis and nonproliferative diabetic maculopathy demonstrated a benefit. The lack of long-term improvement in the majority of cases is in accordance with the hypothesis that ILM peeling may reduce the intraretinal edema, but does not affect the underlying mechanism causing macular edema. So far, only diabetics have shown improvement (still unproven) from ILM peeling, and this study provides no justification for extending the treatment to macular edema of other causes. Large-scale investigations are needed to evaluate the efficacy in certain diagnosis groups.

Ali RR, Sarra GM, Stephens C, Alwis MD, Bainbridge JW, Munro PM, Fauser S, Reichel MB, Kinnon C, Hunt DM, Bhattacharya SS, Thrasher AJ. · Department of Molecular Genetics, Institute of Ophthalmology, University College London, UK. · Nat Genet. · Pubmed #10888879 No free full text.

Abstract: The gene Prph2 encodes a photoreceptor-specific membrane glycoprotein, peripherin-2 (also known as peripherin/rds), which is inserted into the rims of photoreceptor outer segment discs in a complex with rom-1 (ref. 2). The complex is necessary for the stabilization of the discs, which are renewed constantly throughout life, and which contain the visual pigments necessary for photon capture. Mutations in Prph2 have been shown to result in a variety of photoreceptor dystrophies, including autosomal dominant retinitis pigmentosa and macular dystrophy. A common feature of these diseases is the loss of photoreceptor function, also seen in the retinal degeneration slow (rds or Prph2 Rd2/Rd2) mouse, which is homozygous for a null mutation in Prph2. It is characterized by a complete failure to develop photoreceptor discs and outer segments, downregulation of rhodopsin and apoptotic loss of photoreceptor cells. The electroretinograms (ERGs) of Prph2Rd2/Rd2 mice have greatly diminished a-wave and b-wave amplitudes, which decline to virtually undetectable concentrations by two months. Subretinal injection of recombinant adeno-associated virus (AAV) encoding a Prph2 transgene results in stable generation of outer segment structures and formation of new stacks of discs containing both perpherin-2 and rhodopsin, which in many cases are morphologically similar to normal outer segments. Moreover, the re-establishment of the structural integrity of the photoreceptor layer also results in electrophysiological correction. These studies demonstrate for the first time that a complex ultrastructural cell defect can be corrected both morphologically and functionally by in vivo gene transfer.