Progressive RPE atrophy around disciform scars.
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Atrophy↗
Biomedical subjects
M A Zarbin
Publications and source records attributed to M A Zarbin.
Retinal haemorrhages in a young patient with homocysteinuria.
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Child↗
Use of viscodissection and silicone oil in vitrectomy for severe diabetic retinopathy.
Improvement in surgical techniques has led to improved anatomic and functional success rates following surgery for severe complications of proliferative diabetic retinopathy (PDR). We compared the anatomic and functional outcomes of surgery in a non-randomized, consecutive case series of patients with severe PDR. We found that viscodissection using Healon provides outcomes comparable to conventional pick and scissors dissection. We also found that adjunctive use of silicone oil can salvage selected cases with particularly severe manifestations of PDR (e.g., the fibrinoid syndrome). With proper selection of patients and techniques, the anatomic success rate can exceed 80% even in the most severe cases. The goal of this paper is to show the applicability of using viscodissection and silicone oil infusion during vitrectomy in eyes with severe PDR.
Diabetic Retinopathy↗
Vitrectomy with silicone oil infusion in severe diabetic retinopathy.
AIMS: To determine the results of pars plana vitrectomy (PPV) and silicone oil infusion (SOI) in severe proliferative diabetic retinopathy (PDR). METHODS: The records of 23 eyes (21 patients: 12 males, nine females) with PDR who had undergone PPV and SOI were reviewed retrospectively. RESULTS: Average follow up was 5.4 months (range 1-25). Surgical indications were tractional retinal detachment (TRD) (17.4%), traction-rhegmatogenous retinal detachment (TRRD) (8.7%), TRD with vitreous haemorrhage (VH) (48%), TRD with neovascular glaucoma (NVG) (8.6%), TRD with fibrinoid syndrome (FS) (17.3%). With one operation, the retinal reattachment rate was 17/23 (74%). Among these 23 eyes, 11 (48%) had previously failed vitrectomy, and the retina was attached in 8/11 (73%) with a single procedure. With additional surgery employing PPV and SOI, the final reattachment rate was 20/23 (87%). The only cases with intraocular pressure <5 mm Hg had retinal detachment. Postoperative visual acuity (VA) improved in 10 eyes (44%), was unchanged in three (12%), and decreased in 10 eyes (44%). CONCLUSION: SO tamponade is useful in severely diseased eyes with PDR, even in the presence of rubeosis iridis (RI) and NVG, FS, or in cases with previously failed vitrectomy, especially in the presence of RI.
Adult↗
Epiretinal membrane removal in diabetic eyes: comparison of viscodissection with conventional methods of membrane peeling.
AIMS: To compare conventional methods of epiretinal membrane peeling with viscodissection. METHODS: 154 eyes with proliferative diabetic retinopathy (PDR) that underwent pars plana vitrectomy with membrane dissection (89 traditional, 65 viscodissection) were studied retrospectively. Incidence of retinal breaks (RBs), length of time under anaesthesia, postoperative intraocular pressure, retinal reattachment rate, and final visual acuity (VA) were measured. RESULTS: To compare cases of similar complexity, a "complexity score" was defined. The average complexity score for cases done with and without viscodissection was 4.7 and 3.2, respectively. The mean frequency of RBs in eyes undergoing viscodissection was 0.43 (SD 0.5) v 0.14 (0.35) RBs/eye without viscodissection. In complex cases, the frequency of posterior/peripheral RBs was 0.31 (0.47)/0.13 (0.34) RBs/eye, respectively, with viscodissection v 0.12 (0.33)/0.23 (0.43) RBs/eye without viscodissection. None of these differences were statistically significant. The average preoperative/postoperative VA (logMAR) in the viscodissection cohort was 1.7/1.3 (range 0.3 to >1.9/0.1 to >1.9) v 1.4/1 (range 0.48 to >1.9/0.1 to >1.9) in the non-viscodissection cohort, among eyes with 6 months of follow up. Anaesthesia duration was significantly shorter for cases done without viscodissection (p=0.03), but cases done with viscodissection were significantly more complex than cases done without viscodissection (p<0.0001). CONCLUSION: Viscodissection appears to be a safe and effective alternative technique in eyes with PDR. Owing to the retrospective nature of the study, additional studies are warranted.
Diabetic Retinopathy↗
Early attachment of uncultured retinal pigment epithelium from aged donors onto Bruch's membrane explants.
Retinal pigment epithelium (RPE) transplantation might replace cells lost as a consequence of choroidal neovascular membrane excision in patients with age-related macular degeneration (AMD). Autologous transplantation of RPE cells harvested from a peripheral biopsy may overcome problems of immune rejection. To study the feasibility of autologous RPE cell transplantation, the authors examined the attachment of freshly harvested RPE cells from aged donors onto Bruch's membrane explants, debrided to (1) remove or (2) preserve the RPE basement membrane. Human retinal pigment epithelial sheets were harvested from adult donor eyes (N = 12, mean age 79.00 +/- 9.40 years) and, following incubation in collagenase, were mechanically fragmented into microaggregates. Microaggregates (approximately 120 000 cells) were seeded onto the paired explants (7 mm diameter) and incubated for 20 min, 1, 4, or 24 hr at 37 degrees C. The percent coverage of the debrided surface by microaggregates was determined by sampling the center of the explants with scanning electron microscopy. RPE microaggregate attachment to Bruch's membrane was significantly greater at all time points analysed in samples with intact basement membrane versus those with an exposed inner collagenous layer. Coverage of debridements retaining intact RPE basement membrane was 1.83 +/- 1.10% at 20 min, 3.54 +/- 2.14% at 1 hr, and 8.68 +/- 2.63% at 4 hr. Coverage of debridements lacking basement membrane was 0.10 +/- 0.04% at 20 min, 0.39 +/- 0.25% at 1 hr, and 0.63 +/- 0.42% at 4 hr. Based on their morphologic appearance, many cells were dying as early as 1 hr following seeding. To increase surface coverage, the authors seeded four times the above number of cells and incubated the specimens for 1 hr. Coverage on explants lacking RPE basement membrane showed no increase in the number of cells attached to the inner collagenous layer. There was a significant approximately three-fold increase in the number of cells attached in the presence of basement membrane. These results indicate that if RPE cells from aged human donors are used for transplantation, some modification of the Bruch's membrane surface or the cells must be considered for cell attachment and eventual cell survival.
Aged↗
Unintentional transplantation of autologous retinal pigment epithelium during limited macular translocation.
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Aged↗
Visual loss after renal transplantation.
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Blindness↗
Short-term study of allogeneic retinal pigment epithelium transplants onto debrided Bruch's membrane.
PURPOSE: To investigate the survival and behavior of retinal pigment epithelium (RPE) microaggregates transplanted onto hydraulically debrided Bruch's membrane and to compare results of using three different vehicles for cell delivery. METHODS: RPE microaggregates obtained from male cats were transplanted onto the tapetal area of female cats after native RPE was debrided. For the control, one of three vehicles was introduced into the debridements. Each transplant or control specimen was analyzed histologically and immunohistochemically. Transplanted male RPE cells were identified by in situ labeling of the cat Y chromosome. RESULTS: Histologically, significant numbers of condensed, darkly stained RPE nuclei were observed in all transplants compared with few TUNEL-positive RPE cells. Cellular retinaldehyde-binding protein was present up to day 7 in all RPE cells in transplants. In both transplant and control specimens, the antibody against the Ki-67 nuclear antigen labeled some RPE cells at day 3. TUNEL-positive outer nuclear layer nuclei were most frequently observed at day 1, but were much less frequent at 7 days in both transplant and control specimens. CONCLUSIONS: Transplanted RPE appeared to retain at least some markers of differentiation up to 7 days after surgery. Some proliferation of transplanted RPE cells was also seen. Apoptotic cell death of transplanted RPE, as judged by TUNEL staining was observed rarely. RPE transplants imposed no adverse effect on the overlying retina. RPE survival appeared to be similar with each of the three vehicles for cell delivery.
Animals↗
Morphologic preservation and variability of human donor retina.
PURPOSE: To facilitate studies of human retina and utilization of human retinal tissue for treatment of retinal diseases, we studied morphologic preservation in postmortem human retina. METHODS: Morphology of retinas from thirty-one human eyes was examined using light and electron microscopy. The inner and outer retina, rod and cone photoreceptor cells, and central and peripheral retina were compared with regard to morphologic preservation. Possible factors affecting survival were analyzed. RESULTS: The earliest postmortem change was vacuolation of the nerve fiber layer within a few hours postmortem, followed by vacuolation and cytoplasmic swelling of the inner retina. As compared with the inner retina, outer retinal structure was better preserved, i.e., the photoreceptor cells maintained better morphology. Rod cell morphology was better preserved than cone cell morphology, with good preservation of the rod outer segment disc membranes and the inner segment mitochondrial membranes. Thus, well-preserved rod photoreceptor cells were evident in specimens at least 48-hours postmortem. Peripheral retina was better preserved than the central retina including the fovea and perifovea. Factors affecting anatomical integrity included the total time postmortem and, more importantly, the time between death and enucleation. Other factors, including age and sex, did not appear to affect morphological preservation in the present study. CONCLUSIONS: Human retina postmortem remained morphologically intact for a relatively long period of time, with differential preservation among different geographic areas and cell types. This morphologic evidence is consistent with previous findings of functional preservation (e.g. , photoresponses) in such tissue. This study may shed some light on understanding of human retina and its utilization for retinal transplantation.
Adolescent↗
Abnormal collagen fibrils in nanophthalmos: a clinical and histologic study.
PURPOSE: To report the successful treatment of choroidal detachment in a patient with nanophthalmos and to report histopathologic findings in this patient's sclera. METHODS: Choroidal detachment, secondary angle closure, and nanophthalmos were diagnosed using biomicroscopy, indirect ophthalmoscopy, and echography. Full-thickness sclerectomies in four quadrants were made on the right eye. Sclerae from these sclerectomies were studied ultrastructurally. RESULTS: Best-corrected visual acuity improved to RE, 20/60 from 20/100 preoperatively; the anterior chamber deepened, and the choroidal detachment resolved. Histopathologic studies of each of the three scleral layers disclosed abnormal collagen fibrils that were frayed, split, and contained lightly stained cores. CONCLUSION: New findings include the identification of collagen with lightly stained centers and identification of differences in collagen morphology in different areas of the sclera in a nanophthalmic eye.
Adult↗
Coats' response in Leber's congenital amaurosis.
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Abnormalities, Multiple↗
Diagnosis of phacoanaphylactic endophthalmitis by fine needle aspiration biopsy.
Diagnosis of phacoanaphylactic endophthalmitis (or lens induced uveitis), a rare autoimmune disease, is difficult due to variable clinical presentation. We sought to diagnose a case based on the cytopathology of the anterior chamber aspirate. This is a case report of spontaneous phacoanaphylactic endophthalmitis in a 79-year-old woman with no history of eye trauma or surgery. After clinical examination, diagnostic anterior chamber paracentesis was performed. Cytologic examination of the aspirate revealed polymorphonuclear leukocytes, histiocytes, and plasma cells surrounding amorphous lens material. A mature cataract was removed subsequently, and the eye has remained free of inflammation postoperatively. As the clinical diagnosis of phacoanaphylactic endophthalmitis is often difficult, cytopathology of an anterior chamber aspiration specimen may be useful in diagnosing this rare, treatable condition. As far as we know, this is the first case report of the diagnosis of phacoanaphylactic endophthalmitis solely by anterior chamber fine needle aspiration biopsy.
Aged↗
In vitro transplantation of fetal human retinal pigment epithelial cells onto human cadaver Bruch's membrane.
Retinal pigment epithelium transplantation has been proposed as adjunctive treatment for age-related macular degeneration following surgical excision of choroidal neovascular membranes. The goal of this study was to develop a model to evaluate retinal pigment epithelium transplantation onto human Bruch's membrane in vitro. We investigated the ability of cultured fetal human retinal pigment epithelium to colonize human cadaver Bruch's membrane, determined the incubation time needed to form a monolayer and to exhibit apical microvilli and tight junctions, and assessed the production of basement membrane. Freshly enucleated (less than 48 hours old) human eyes were cut through the pars plana, and the anterior segment, vitreous, and retina were removed. The native retinal pigment epithelium was debrided with a surgical sponge. Bruch's membrane and choroid at the macula were trephined with a 7.0 mm diameter trephine and then incubated with 1/2 ml of Dulbecco's modified Eagle's medium +15% fetal calf serum+basic fibroblast growth factor (1 ng ml-1), and fetal human retinal pigment epithelium at a concentration of 242,000 cells ml-1. Specimens were incubated for 1, 4, 6, 8, 12, or 24 hours. The specimens were fixed in half strength Karnovsky's fixative, processed, and analysed with scanning and transmission electron microscopy. The retinal pigment epithelium covered the debrided macular specimens to different degrees at different incubation times. After 1 hour, the cells started to attach and flatten (median percent coverage: 78%). The extent of Bruch's membrane coverage by fetal retinal pigment epithelium varied greatly between specimens. After 4-6 hours, the cells covered the entire debrided surface in a monolayer (median percent coverage: 97.2% at 4 hours, 99.8% at 6 hours). Tight junctions were observed, and the cells had few apical microvilli. The lateral cell borders were obliquely oriented with respect to Bruch's membrane, and the nuclei were elongated, exhibited prominent nucleoli, and were oriented parallel to Bruch's membrane. After 6-8 hours, cells started to become hexagonal (median percent coverage at 8 hours: 99.97%). Cells attached to the inner collagenous layer tended to be flatter than cells attached to residual native basement membrane. At 12 and 24 hours, expression of hexagonal shape, tight junctions, and apical microvilli were observed more frequently (median percent coverage: 99.87% at 12 and 100% at 24 hours). No newly formed basement membrane was observed at these time points. In separate experiments comparing attachment in the presence and absence of native RPE basement membrane, the presence of native retinal pigment epithelial basement membrane promoted the early attachment of the cells and more rapid expression of normal morphology. This in vitro system provides a reproducible way to study the adherence of retinal pigment epithelium to normal and diseased human Bruch's membrane.
Aged↗
Optimization of non-isotopic in situ hybridization: detection of the Y chromosome in paraformaldehyde-fixed, wax-embedded cat retina.
A technique was developed to detect the Y chromosome in paraformaldehyde-fixed diethylglycoldiesterate-embedded cat retina. The Y chromosome specific DNA probe was labeled with digoxigenin through polymerase chain reaction incorporation. After treatment of paraformaldehyde-fixed, diethylglycoldiesterate-embedded tissue sections with deoxyribonucleic acid decondensation and proteolytic digestion, non-fluorescent, non-isotopic in situ hybridization was performed on the retina sections. Most extensive treatment was required for the outer nuclear layer while the inner nuclear layer required more extensive treatment than the retinal pigment epithelial cells. Under optimal pretreatment conditions, the male cat retina displayed black spots which specifically localized at the periphery of the nuclei, while the female cat retina showed negative staining for the Y chromosome specific probe. The technique allows observation of the Y chromosome signal with preservation of retinal morphology and thus may be a valuable tool to discriminate donor cells in retinal pigment epithelial cell and photoreceptor cell transplants.
Animals↗
Culture of human retinal pigment epithelial cells from peripheral scleral flap biopsies.
PURPOSE: We studied various methods for harvesting retinal pigment epithelium (RPE) biopsies from cadaver human eyes of donors over age 60 years. Our goal was to harvest cells for possible autologous RPE cell transplantation in patients with age-related macular degeneration and to test the viability of the RPE after isolation by evaluating explant growth in culture. METHODS: Choroid-RPE biopsies were excised from enucleated human eyes. The RPE was separated from the choroid by treatment with type IV collagenase. RPE patches were cultured. After 100-500 cells had grown out from the explant, the primary cultures were passaged. RESULTS: There was no clear effect of donor age on the ability to establish primary RPE cultures with good morphology from biopsies 2 x 2-10 x 10 mm2 in size. Biopsies 6 x 6 mm2 or larger produced satisfactory primary cultures more than 70% of the time. The number of viable RPE cells (defined as the number of cells adherent to the culture dish 24 h after plating) obtained after enzymatic separation of the RPE and choroid was an important determinant of our ability to establish primary cultures and passage the cells. Primary cultures with good cellular morphology were obtained 100% of the time when RPE explants > 4 mm2 in size were obtained from the biopsy specimen. Seventy-three percent of the biopsies yielding explants > 4 mm2 in size were successfully passaged. CONCLUSIONS: These results suggest that peripheral scleral flap biopsies in aging donors can be used to establish RPE explant primary cultures. These cultures may be suitable as a source for autologous RPE transplantation in patients.
Aged↗
Progressive presumed choriocapillaris atrophy after surgery for age-related macular degeneration.
PURPOSE: The authors sought to evaluate the progression of presumed choriocapillaris atrophy after surgical excision of a subfoveal choroidal neovascular membrane (CNV) in an 80-year-old man with age-related macular degeneration. METHODS: The CNV was excised using a conventional three-port vitrectomy with subretinal dissection. The excised tissue was studied with light and electron microscopy. Preoperative and serial postoperative fluorescein angiograms (FA) and fundus photographs were obtained to study the dissection bed. RESULTS: Seven days after surgery, the FA showed hyperfluorescence in the area previously occupied by the CNV. Six weeks after surgery, this area showed retinal pigment epithelium (RPE) depigmentation, atrophy, or both on clinical examination, and the FA showed presumed choriocapillaris nonperfusion. Seven months after surgery, the area of the RPE depigmentation or atrophy and the corresponding area of presumed choriocapillaris nonperfusion had enlarged. The area of depigmentation or atrophy continued to enlarge for 1 year after surgery. Histologically, the excised CNV specimen disclosed RPE cells but no choriocapillaris. CONCLUSIONS: Presumed choriocapillaris nonperfusion after CNV excision may be due to RPE removal at surgery and may progress postoperatively.
Aged↗
Clinicopathological correlation of primary and recurrent choroidal neovascularisation following surgical excision in age related macular degeneration.
AIMS/BACKGROUND: Fluorescein angiography and histopathological findings were correlated in two patients with recurrent choroidal neovascular membranes (CNVs) in an attempt to gain insight into the possible causes of recurrent CNVs and into the healing response after CNV excision. METHODS: Two patients with recurrent CNVs underwent repeat excision, and the excised tissue was studied with light and electron microscopy. RESULTS: Incomplete CNV excision probably led to the recurrences. The portion initially excised appears to have been anterior to the RPE in case 1. In both cases, recurrent CNVs contained RPE-like like cells suggesting that native RPE can repopulate the dissection bed. The tissue excised at the second operation contained areas with hyperplastic RPE and fragments of Bruch's membrane (external to the RPE basement membrane) in a matrix of fibrillar collagen and fibrocytes, suggesting that initial removal of the CNV can be followed by an abnormal anatomical arrangement of RPE and scarring of Bruch's membrane. CONCLUSIONS: Abnormal resurfacing of the dissection bed by RPE and fibroblasts may underlie, in part, the limited visual outcome often seen after surgical excision of CNVs in age related macular degeneration.
Aged↗