Phenotypic variation of retinal pigment epithelium in age-related macular degeneration.

PURPOSE: To determine whether retinal pigment epithelium (RPE) in eyes with age-related macular degeneration (ARMD) express vimentin and alpha smooth muscle actin (alphaSMA), two cytoskeletal proteins associated with phenotypic variation in culture. METHODS: Six eyes with late ARMD and three age-matched control eyes were preserved in buffered 4% paraformaldehyde and cryosectioned at 10 microm. Stages of RPE morphology and pigmentation were assessed by the Alabama Age-Related Macular Degeneration Grading System. Vimentin, alphaSMA, and glial fibrillary acidic protein (GFAP) expression was detected by indirect immunofluorescence. These results were compared with regional variations in disease severity. RESULTS: RPE changes in ARMD included acquired expression of vimentin, but alphaSMA-positive cells were rare. GFAP expression increased in Müller cells in the neural retina in association with RPE changes and photoreceptor degeneration. CONCLUSIONS: The initial stages of RPE changes in eyes with ARMD mimic those reported for cultured RPE cells. The absence of alphaSMA-positive cells in regions of RPE atrophy suggests that RPE are lost rather than persist in a dedifferentiated state.     

Autologous translocation of the choroid and retinal pigment epithelium in age-related macular degeneration

PURPOSE: To evaluate the autologous translocation of peripheral choroid and retinal pigment epithelium (RPE) in 45 eyes of 43 patients with age-related macular degeneration (AMD). DESIGN: Prospective nonrandomized study. METHODS: All patients had visual loss due to AMD (n = 5 classic membranes, n = 14 occult, n = 2 mixed, n = 16 pigment epithelial detachment (PED), n = 5 subretinal hemorrhage, n = 3 geographic atrophy). After extraction of the neovascular complex, an autologous peripheral full-thickness explant of RPE, Bruch membrane, and choroid was translocated from the midperiphery to the macula. RESULTS: Preoperative distant visual acuity ranged from 20/800 to 20/40. Reading vision ranged from 1.4 logarithm of reading acuity determination (logRAD) to 0.5 logRAD (0.04 to 0.32 Snellen equivalent). Revision surgery was required in 22 eyes as a result of proliferative vitreoretinopathy (PVR), retinal detachment, macular pucker, or vitreous hemorrhage. In eight patients, the patch was renewed. At six months, distant visual acuity ranged from light perception to 20/50 (increase of 15 letters in four eyes). Reading vision ranged from 1.4 to 0.4 logRAD. Visual outcome was unrelated to the type of AMD. Vascularization of the transplant was visible on indocyanine green (ICG) angiography in 40 of 42 eyes. In most patients, autofluorescence of the pigment epithelium was coincident with revascularization of the graft. Fixation on the patch was positively related to visual acuity. CONCLUSIONS: Autologous translocation of a full-thickness transplant of choroid and RPE usually results in a vascularized and functioning graft. Vascularization was even achieved in patients with geographic atrophy. Fixation stability and microperimetry before the patch translocation may be helpful in selecting patients who will profit from surgery.     

Antioxidant enzymes in the macular retinal pigment epithelium of eyes with neovascular age-related macular degeneration

PURPOSE: To test the hypothesis that neovascular age-related macular degeneration is related to oxidative stress involving the macular retinal pigment epithelium. This study investigated, as a function of age, levels of enzymes that defend tissues against oxidative stress in the macular retinal pigment epithelium of human eyes with this disease. METHODS: Surgical specimens of macular choroidal neovascular membranes from eyes with age-related macular degeneration and the macular regions of whole donor eyes with neovascular age-related macular degeneration or without evident ocular disease were studied by quantitative electron microscopic immunocytochemistry with colloidal gold-labeled second antibodies. Relative levels in retinal pigment epithelium cell cytoplasm and lysosomes were determined of five enzymes believed to protect cells from oxidative stress, as well as levels of the retinal pigment epithelium marker cytoplasmic retinaldehyde-binding protein, for comparison with the enzymes. RESULTS: Copper, zinc superoxide dismutase immunoreactivity increased and catalase immunoreactivity decreased with age in cytoplasm and lysosomes from macular retinal pigment epithelium cells of normal eyes and eyes with age-related macular degeneration. Cytoplasmic retinaldehyde-binding protein immunoreactivity showed no significant relationship to age or the presence of neovascular age-related macular degeneration. Glutathione peroxidase immunoreactivity was absent from human retinal pigment epithelium cells. Both heme oxygenase-1 and heme oxygenase-2 had highly significantly greater immunoreactivity in retinal pigment epithelium cell lysosomes than in cytoplasm, differing from the much greater cytoplasmic immunoreactivity of the other proteins studied. This immunoreactivity decreased with age, particularly in the lysosomes of retinal pigment epithelium cells from eyes with neovascular age-related macular degeneration. These decreases were of borderline significance (P = .067 for heme oxygenase-1; P = .12 for heme oxygenase-2) when eyes with age-related macular degeneration were compared with normal eyes by multivariable logistic regression. CONCLUSIONS: The high heme oxygenase-1 and heme oxygenase-2 lysosomal antigen levels in macular retinal pigment epithelium cells of eyes with neovascular age-related macular degeneration suggest that oxidative stress causes a pathologic upregulation of these enzymes. Increased lysosomal disposal may indicate that the reparative functions of these enzymes are accompanied by deleterious effects, necessitating their rapid removal from the cell. The much higher heme oxygenase-1 and heme oxygenase-2 antigen levels in macular retinal pigment epithelium cells from younger individuals suggest that protective mechanisms against oxidation and, hence, presumably to the development of age-related macular degeneration, decrease with age.     

Spontaneous rip of the retinal pigment epithelium with a macular hole in neovascular age-related macular degeneration

PURPOSE: To report a case of retinal pigment epithelial tear associated with a macular hole in a patient with neovascular age-related macular degeneration (AMD). DESIGN: Observational case report. METHODS: An 87-year-old woman with AMD-related fibrovascular pigment epithelial detachment associated with vision loss was followed with sequential fundus photography, fluorescein angiography, and optical coherence tomography for 8 months. RESULTS: The detachment developed into a retinal pigment epithelium tear with macular hole formation. The temporal evolution of the lesion and optical coherence tomography findings suggested that the retinal pigment epithelium tear led to stretching forces along the posterior surface of the neurosensory retina with secondary foveal dehiscence. CONCLUSION: Macular hole formation is one mechanism by which retinal pigment epithelium tears may cause vision loss in AMD.     

Transplantation of fetal retinal pigment epithelium in age-related macular degeneration with subfoveal neovascularization

Background: Age-related macular degeneration (ARMD) is caused by abnormal retinal pigment epithelium (RPE) and may be complicated by choroidal neovascularization. The object of treatment would be to replace the diseased RPE with normal human RPE. Method: Five patients with ARMD (preoperative visual acuity 0.08–0.2) underwent removal of subretinal fibrovascular membranes using pars plana vitrectomy techniques. Human fetal RPE (15–17 weeks gestational age) was cultured and transplanted as a monolayer patch into the subretinal space. Transplants were followed by funduscopy and fluorescein angiography. Macular function was assessed using scanning laser ophthalmoscopic (SLO) microperimetry. Results: Three RPE transplants were placed in the fovea; two were placed parafoveally. All transplants have survived for 3 months. They have grown and increased in size covering part of the epithelial defect caused by removal of the fibrovascular membrane. SLO microperimetry indicated that visual function was present in four of the transplants at 1 month but in only two at 3 months after surgery. Function over the transplants, especially those in the fovea, was compromised by cystoidlike macular edema. Conclusions: Human fetal RPE transplants survive well in the macula for as long as 3 months. They are capable of growing to cover epithelial defects caused by removal of subretinal neovascular membranes. The causes for development of macular edema in transplants directly in the fovea warrant further evaluation.     

Autologous translocation of large retinal pigment epithelium choroid patches in age-related macular degeneration

BACKGROUND: The latest development in ARMD surgery is the translocation of an autologeous pigment epithelium choroid patch. The method has technical shortcomings: The transplant is excised including the overlaying retina and inserted through a retinotomy near the posterior pole thus causing iatrogenic field defects. For the same reasons the size of the transplant is limited. MATERIALS AND METHODS: The technique was modified as follows: lens surgery using a special PCL with equal power in water and silicone oil, 180 degrees retinotomy just at the temporal ora serrata, subretinal surgery including patch transplantation with the retina folded over nasally and fixed by PFCL, complete silicone oil tamponade without any water remaining. PATIENTS: 12 consecutive cases, age 79 (70 - 86) years, 4 RPE detachments and rips, 8 subretinal hemorrhages from wet ARMD, follow-up in 10 eyes over 15.3 (3 - 23) months. Time courses for visual acuity, depth of central scotoma, OCT and FAG. RESULTS: The mean diameter of the transplants was 16.5 (9 - 33) degrees . Silicone explantation in 7 / 10. Complications in 3 / 10: 1 macula puckering, 1 peripheral detachment, 1 PVR detachment. According to FAG the transplant vascularises in 4 - 6 weeks. 4 / 10 eyes reached visual acuity > 0.2 with limited reading capability. Central scotoma depth remained constant at -11 dB. Function deteriorated again after 6 - 9 months with cystoid degeneration and retinal thickening. 8 / 11 patients estimated the operated eye to be superior to the untreated partner eye. CONCLUSIONS: Patch transplantation is able to restore limited reading capability in eyes having minor damage of the central retina. The best cases for this type of operation are RPE rips and recent sub-RPE haemorrhages. The functional success lasts 5 to 9 months, then the retina over the transplant begins to degenerate.     

Focal proliferation of retinal pigment epithelium as risk factor in age-related macular degeneration

Background: Clinical studies have demonstrated the relevance of focal RPE proliferations in early AMD as risk factors for visual loss caused by late AMD. Angiographically these focal RPE proliferations are characterized as small hypofluorescent spots with hyperfluorescent rim without leakage. Corresponding to histological and experimental studies they can be interpreted as small areas of occult choroidal neovascularizations covered by proliferated RPE cells. The characterization of the long-term prognosis of these lesions was the aim of the present study. Patients and methods: Ninety-eight patients (52 female, 46 male) were reexamined clinically and angiographically with a follow-up of 2–12 years (mean 6.5 years). Results: Visual loss of two lines or more could be observed in 64.5 % of patients with final visual acuity less than 20/100 in 24.5 % of patients. Morphologically the changes in visual acuity were related to the progression towards classical choroidal neovascularizations in 32.7 % of patients. In addition 11.2 % of patients demonstrated a regression of the small occult membrane with the development of small areas of RPE atrophy covering the size of the original occult neovascularization. In 10.2 % of the patients enlargement of the lesion was observed, resulting in a large occult choroidal neovascularization without signs of classical membranes, and in 45.9 % of patients the clinical and angiographical situation was unchanged. The most important prognostic factor correlating with visual loss was the presence of a disciform lesion in the fellow eye and of multiple drusen in the examined eye. Other factors like the size or location of the focal RPE proliferation and the duration of follow-up did not correspond with visual loss. Conclusions: Focal RPE proliferations in early AMD interpreted as small occult choroidal neovascularizations are associated with a high risk of visual loss. Especially if these lesions are associated with multiple drusen and a disciform lesion in the fellow eye, nearly all patients are at risk for visual loss. These changes may therefore characterize a special high-risk group for future prophylactic treatments in early AMD, but because of the high risk for the development of classical choroidal neovascularizations in this group, these results are also very important for the planning of prophylactic laser trials for drusen in early AMD.      

Changes in select redox proteins of the retinal pigment epithelium in age-related macular degeneration

PURPOSE: To examine changes of select reduction-oxidation (redox) sensitive proteins from human donor retinal pigment epithelium (RPE) at four stages of age-related macular degeneration (AMD). DESIGN: Experimental study. METHODS: Human donor eyes were obtained from the Minnesota Lions Eye Bank and graded using the Minnesota Grading System (MGS) into four stages that correspond to stages defined by the age-related eye disease study (AREDS). Protein content in RPE homogenates was measured using Western immunoblotting with protein-specific antibodies. RESULTS: The content of several antioxidant enzymes and specific proteins that facilitate refolding or degradation of oxidatively damaged proteins increased significantly in MGS stage 3. These proteins are involved in the primary (copper-zinc superoxide dismutase [CuZnSOD], manganese superoxide dismutase [MnSOD], and catalase) and secondary (heat shock protein [HSP] 27, HSP 90, and proteasome) defense against oxidative damage. Additionally, the insulin pro-survival receptor exhibited disease-related upregulation. CONCLUSIONS: The pattern of protein changes identified in human donor tissue graded using the MGS support the role of oxidative mechanisms in the pathogenesis and progression of AMD. The MGS uses nearly identical clinical definitions and grading criteria of AMD that are used in the AREDS, so our results apply to clinical and epidemiologic studies using similar definitions. Results from our protein analysis of human donor tissue helps to explain altered oxidative stress regulation and cell-survival pathways that occur in progressive stages of AMD.     

Slow leakage from the retinal pigment epithelium (ooze) in age-related macular degeneration

The authors describe a condition called retinal pigment epithelial (RPE) ooze in patients with age-related macular degeneration. Patients with ooze have a neurosensory retinal detachment, a slowly progressive indiscrete leakage of fluorescein dye from the level of the retinal pigment epithelium, and no other signs of choroidal neovascularization. Sixteen patients with RPE ooze were followed for a mean of 4.5 years without treatment. Nine patients had a single round or oval area of leakage. In seven of these patients, choroidal neovascular membranes developed, with moderate to poor visual outcomes. The other seven patients had multiple smaller areas of leakage from the level of the RPE. None of these patients had a choroidal neovascular membrane, and all had resolution of the subretinal fluid with good final visual acuities. Patients with discrete round or oval RPE oozes appear to be at a high risk for the development of more definite choroidal neovascular membranes and vision loss.     

The natural history of serous retinal pigment epithelium detachment in patients with age-related macular degeneration

One hundred ten patients with serous detachment of the retinal pigment epithelium (RPE) were reexamined to enhance our knowledge of the natural course of this condition. All patients were greater than 50 years of age, had age-related macular degeneration, and had neither blood, lipid, nor angiographic evidence of a definite choroidal neovascular membrane (NVM) at the time of the initial examination. All patients were followed up for at least six months except for two patients who had developed a choroidal NVM within the first six months of the initial exam. Forty-five of 140 eyes (32%) developed a choroidal NVM within an average of 19.6 months (median, 12 months). This was associated with a final visual acuity of 20/200 or worse (P less than 0.0001). Ophthalmoscopic and angiographic features present at the initial visit which were associated with the development of NVM and poor final visual acuity were: sensory retinal detachment; increased size of PED; hot spot; late filling; notching; and irregular filling. At the most recent examination, 39% of the eyes had a final visual acuity of 20/20 to 20/40, while 24% of the eyes had a final visual acuity of less than or equal to 20/200.     

Adult retinal pigment epithelial transplantation in exudative age-related macular degeneration

PURPOSE: To improve visual function by retinal pigment epithelial (RPE) cell transplantation and systemic immunosuppression at the time of surgical removal of subfoveal choroidal neovascularization in exudative age-related macular degeneration (AMD). DESIGN: An interventional case series of RPE transplantation in exudative AMD. METHODS: Twelve patients (one eye only) underwent subfoveal membranectomy with transplantation of a sheet of adult human allogeneic RPE cells at a single institution and were followed for one year. Eligibility criteria included age >60, best-corrected acuity < or =20/63 and subfoveal neovascularization < or =9 disk areas on preoperative fluorescein angiography. All patients were started on triple immunosuppression postoperatively. The primary outcome measure was best-corrected vision, with contrast sensitivity and reading speed as secondary outcome measures. RESULTS: The best-corrected visual acuity (P = .085), contrast sensitivity (P = .204), and the reading speed (P = .077) did not change significantly at one year compared with preoperative values. Transplants showed no signs of rejection in patients who were able to continue the immunosuppressants for six months. Postoperative surgical complications included cataract progression requiring surgery (three of eight phakic eyes), retinal detachment (three eyes), intraoperative retinal breaks (two eyes), and macular pucker (two eyes). None of the patients developed cystoid macular edema on postoperative fluorescein angiography or postoperative inflammation. CONCLUSIONS: A sheet of adult human allogeneic RPE can be transplanted into the subretinal space in AMD patients at the time of subfoveal membranectomy. Systemic immune suppression appeared to prevent rejection of the transplanted tissue, but did not lead to an improvement in visual function.     

Outcome of transplantation of autologous retinal pigment epithelium in age-related macular degeneration: a prospective trial

PURPOSE: To present the outcome of a consecutive series of patients who had foveal choroidal neovascularization (fCNV) in age-related macular degeneration (AMD) and were treated with subretinal surgery combined with simultaneous transplantation of autologous retinal pigment epithelial (RPE) cells. METHODS: Patients with fCNV who were not eligible for laser or photodynamic therapy were included in the study. They underwent subretinal membrane excision with simultaneous transplantation of autologous RPE cells. Eyes with membrane excision alone served as the control. Tests included best corrected visual acuity for far and near with Early Treatment Diabetic Retinopathy Study (ETDRS) and Jaeger charts, multifocal (mf)ERG, central visual field analysis, optical coherence tomography (OCT), and angiography, before surgery, and 1 month and 3 months after treatment, and at 3-month intervals thereafter. RESULTS: The results of final examinations of 53 eyes are presented. In 39 eyes, RPE transplantation was performed (group 1); 14 eyes had membrane excision alone (group 2). In group 1, visual acuity improved significantly, two or more lines in 21 (53.8%) patients; remained stable in 12 patients (30.8%); and decreased two or more lines in 6 patients (15.4%; P=0.0062). In group 2, the corresponding values were 21.1%, 57.8%, and 21.1% (P=0.5377 NS). Statistical analysis of results in the two groups showed a trend in favor of group 1 (P=0.9714). The difference in reading acuity was significant between the two groups (mean change in group 1: 1.85 +/- 0.42 vs. 0.43 +/- 0.47 in group 2; P=0.0001). mfERG response density changes were significantly different between groups 1 and 2 (P=0.0094). No significant decreases in central visual field defects were detected. OCT showed the postoperative median retinal thickness in the lesion area in group 1 to be higher (242.31 +/- 12.30 microm) than in group 2 (202.07 +/- 10.68 microm), showing a trend (P=0.0682). CONCLUSIONS: Patients undergoing fCNV removal with autologous transplantation of RPE reached significantly better reading acuity and higher mfERG-response density than control subjects. The results provide evidence that autologous transplantation of RPE is a beneficial supplement to membrane excision alone in patients with fCNV in AMD and may be regarded as a reasonable treatment option.     

Evolution of retinal pigment epithelium detachment after photodynamic therapy for choroidal neovascularization in age-related macular degeneration

PURPOSE: To report a case of pigment epithelium detachment (PED) which appeared after photodynamic therapy (PDT) and was followed up for 50 months. METHODS: Case report. RESULTS: A 71-year-old woman with occult choroidal neovascular membrane due to age-related macular degeneration (ARMD) developed PED 48 hours after PDT. The patient was studied with fluorescein angiography (FA) and optical coherence tomography (OCT). Fluorescein angiographic evidence of PED remained essentially unchanged during the follow-up period of 50 months. Although OCT initially gave clear evidence of PED, in the last 12 months of follow-up the PED appears to have resolved. CONCLUSIONS: Photodynamic treatment could be involved in the occurrence of PED in occult choroidal neovascular membrane due to ARMD. In this particular case OCT could be considered since it offers useful information in the pretreatment and the post-treatment follow-up period.     

Optical coherence tomography on autologous translocation of choroid and retinal pigment epithelium in age-related macular degeneration

PURPOSE: To analyse structural changes after autologous translocation of choroid and retinal pigment epithelium (RPE) in patients with age-related macular degeneration (AMD) using optical coherence tomography (OCT). METHODS: We performed a prospective nonrandomised study in 29 consecutive patients, who underwent submacular surgery with translocation of an autologous full-thickness graft of RPE, Bruch's membrane, and choroid. All patients had recent loss of reading vision due to AMD. OCT was performed before surgery and at 3- and 6- month follow-up to analyse the morphological appearance of the graft and the overlying retina. RESULTS: Maximum retinal thickness decreased from mean 408 microm (standard deviation (SD) 127 microm) preoperative to mean 373 microm (SD 104 microm) at 6-month follow-up (P=0.094). In 11 cases (40%), a nearly physiological shape of the retina was seen at this time point. A macular hole persisted in two eyes after silicone oil removal. In most eyes, the highly reflective band of the graft presumably corresponding to RPE was continuous with the surrounding RPE band in all six OCT scans. Eyes with flat appearance of the graft at 6-month follow-up (<300 microm) showed a significantly better functional outcome than eyes with more prominent grafts. Interestingly, most patients did not complain about metamorphopsia, even though the graft was prominent or wrinkled in some cases. CONCLUSION: OCT is a useful tool in monitoring intra- and subretinal changes after subretinal surgery with graft translocation. We demonstrated that graft translocation may lead to a normalisation of retinal thickness and stabilisation of visual acuity.