Cornelia M. Mooy

Prognostic parameters in uveal melanoma: a review

Histologic cell type, largest tumor diameter and tumor location have traditionally been regarded as the leading predictors of survival for uveal melanoma. Morphological cell typing is, however, subjective to variations in interpretation. More objective classification parameters have emerged from extensive cytomorphometrical and DNA flow cytometrical studies. For patients with uveal melanoma there is no effective therapy if metastases have developed, and the median survival after clinical diagnosis of hepatic metastases is extremely poor. Current research focuses on the mechanisms underlying the metastatic process, including tumor vasculature, cytogenetics, oncogene activation, immunology, melanoma-associated antigens and tumor cell migration (cell-cell and cell-matrix interaction). Several new prognostic parameters have emerged from these studies, such as closed vascular patterns, loss of one chromosome 3, and different indices of cell proliferation. Furthermore, considerable genotypical and phenotypical differences have been found between uveal and cutaneous melanoma. In prospective studies on large series of melanomas a combination of histopathological and/or clinical prognostic parameters might be selected with high sensitivity and specificity, providing a way of selecting patients at high risk of developing metastatic disease, who might be eligible for adjuvant therapy.

Histologic Features of the Early Stages of Age-related Macular Degeneration: A Statistical Analysis

The age distribution, frequency, and correlation among histologic macular changes, including formation of a basal laminar deposit, drusen, and thickening and calcification of Bruchs membrane, were studied by light microscopy. The authors studied 182 unpaired postmortem human maculae from patients between 8 and 100 years of age. In addition, 45 maculae of contralateral eyes and the peripheral retina of 50 eyes were studied. In 92%, Bruchs membrane was thickened starting at age 19, and calcifications in this membrane were found in 59% starting at age 33. In 37% of the maculae, hard drusen were found starting at age 34. Soft drusen were found in 10% beginning at age 54. Basal laminar deposit was found in 39% of the maculae starting at age 40. All changes correlated strongly with age (P less than 0.0001). No sex differences were found. Fellow eyes showed similar aging changes (P less than 0.001). The presence of basal laminar deposit in the macula correlated with basal laminar deposit-like material in the peripheral retina (correlation coefficient, 0.39; P less than 0.003), whereas drusen in the macula correlated with drusen in the peripheral retina (correlation coefficient, 0.42; P = 0.001). Geographic atrophy was found in 6.6% of the eyes from subjects older than 70 years and subretinal neovascularization in 3.8%, especially in the maculae with basal laminar deposit.

Early stages of age-related macular degeneration: an immunofluorescence and electron microscopy study.

In subretinal neovascularisation capillaries originating from the choriocapillaris must cross Bruchs membrane to reach the subretinal pigment epithelial space. Thus gaps in Bruchs membrane have to be formed before subretinal neovascularisation. Histological examination of eyes with subretinal neovascularisation or disciform scars has shown macrophages adjacent to thin areas and ruptures in Bruchs membrane. This has been interpreted as phagocytosis of Bruchs membrane. The purpose of this study was to investigate whether immune complex depositions can be detected in maculae with early stages of age-related macular degeneration and to explain the macrophage reaction before the disciform reaction. A series of 20 human maculae were examined by direct immunofluorescence light microscopy to detect the presence of immune complexes with antibodies directed against immunoglobulins, fibrinogen, and complement factors. Transmission electron microscopy on several maculae was performed to identify the macrophages. Macrophages were observed in close relation to the readily recognisable long spacing collagen, which suggested that long spacing collagen was selectively internalised by these cells. Definite immune complex depositions were not found in basal laminar deposits or drusen. Linear deposits of fibrinogen and complement were frequently found in the outer collagenous zone of Bruchs membrane. However, because of the absence of immunoglobulins, it seems unlikely that these non-specific deposits might cause chemoattraction of macrophages and play a role in the initial phase of the development of subretinal neovascularisation and disciform macular degeneration.

Autologous peripheral retinal pigment epithelium translocation in patients with subfoveal neovascular membranes

Aim: To evaluate the possibility of translocating autologous peripheral retinal pigment epithelial (RPE) cells and enhance their adhesion to improve functional outcome after choroidal neovascular membrane extraction in patients with subfoveal neovascular membranes. Methods: A prospective, non-controlled surgical study in eight consecutive patients operated between February and July 2001 with final data monitoring in July 2002. All patients had mixed subfoveal membranes of 2–4 disc diameters. Functional tests included Snellen vision and central fixation testing. During vitrectomy, after the extraction of the neovascular complex, 8×104–16×104 RPE cells were removed from the periphery and translocated under the macula following the submacular injection of 2 μg of poly-l-lysine to promote adhesion of the cells. Results: With a follow up ranging from 3 months to 16 months, a pigmented area was seen in the extraction bed of the neovascular membrane in only one patient. Fixation was at the edge of the extraction bed in three patients. Vision remained the same in five patients and deteriorated in three (all with retinal detachment). Retinal detachment due to proliferative vitreoretinopathy occurred in three patients. Conclusions: The translocation of autologous peripheral RPE cells after membrane extraction was technically possible in a sterile manner, but was associated with a high proliferative vitreoretinopathy rate and in the present series had no measurable positive effect on functional outcome.

Increased prevalence of disciform macular degeneration after cataract extraction with implantation of an intraocular lens.

After cataract extraction with implantation of an intraocular lens the increased transmission of ultraviolet and blue light may accelerate the development of age-related macular degeneration by producing free radicals in the retina. The maculae of 82 randomly selected postmortem human pseudophakic eyes and 16 fellow phakic eyes were examined by light microscopy. The presence of a basal laminar deposit, hard and soft drusen, thickening and calcification of Bruchs membrane, geographic atrophy, subretinal neovascularisation, and disciform scars was assessed in a standardised way. An age-matched series of 126 postmortem phakic eyes was used as control group. There was no difference between the two groups, except for a higher prevalence of hard drusen (exact trend test, p = 0.038) and disciform scars for the pseudophakic eyes (Fishers exact test, p = 0.007). There was no significant correlation between either age-related changes in the macula or disciform degeneration and the length of time between cataract surgery and death. No significant difference was found between pseudophakic eyes with or without ultraviolet filter. These findings do not confirm that disciform scar formation is caused by an increase in ultraviolet or blue light.

Is Basal Laminar Deposit Unique for Age-Related Macular Degeneration?

The ultrastructural nature and distribution of basal laminar deposit, considered to be a precursor of age-related macular degeneration, were studied in 42 human maculae. Basal laminar deposit was found from age 19 years on, not only between the retinal pigment epithelial cells and their basement membrane but also more often on the choriocapillary side of Bruchs membrane. No direct relationship was found with other aging changes, such as calcifications in Bruchs membrane, accumulation of lipofuscin granules, or drusen in the macular area. Material similar to basal laminar deposit can be found in the trabecular system, in the cornea, and also in many other organs and tissues. On a structural and morphometrical basis, we think that basal laminar deposit is similar to fibrous long-spacing collagen and thus does not seem to be a purely ocular abnormality.

Immunohistochemical light and electron microscopy of basal laminar deposit

The formation of basal laminar deposit (BLD) is one of the histopathologic changes in the aging human macula. BLD is assumed to be an early stage of age-related macular degeneration. The location of BLD, between the RPE plasma membrane and its basement membrane and in the outer collagenous zone of Bruchs membrane, and its ultrastructure suggest that it is composed of excessive amounts of basement membrane material. The main components of basement membranes are type IV collagen, heparan sulfate proteoglycans (HSPG) and laminin. Labeled antibodies against these components can therefore be used for the identification and localization of basement membrane material by means of immunohistochemical techniques. In this study the presence of type IV collagen, laminin and HSPG was determined in aged human maculae by immunohistochemistry and immunoelectron microscopy. Tests for the presence of type VI collagen and fibronectin were also performed. We obtained 76 eyes from 68 human subjects at autopsy or after surgical enucleation for anteriorly located choroidal melanomas. The finely granular component of BLD stained positive with antibodies against type IV collagen, HSPG and laminin, but the long-spacing collagen component of BED did not. Neither component of BED was stained with antibodies against type VI collagen or fibronectin. We conclude that BLD consists partly of excess basement membrane material.

Morphologic changes in age-related maculopathy

Age‐related maculopathy (ARM) is a degenerative disorder of the central part of the retina with a rising prevalence in patients 50 years of age and older, and comprises different histopathological changes. The morphologic changes in ARM are described and illustrated with light‐microscopical, electron microscopical, and fundus pictures. Furthermore, the most important biochemical data are given. The most prominent aging changes in early stages of ARM are drusen and basal laminar deposit (BLD), both extracellular deposits, that are assumed to be important in the development of ARM. Drusen accumulate within Bruchs membrane, whereas BLD is present between Bruchs membrane and the retinal pigment epithelium. Although the histopathologic characteristics of the deposits are well documented, the chemical composition has only been partly resolved. Biochemical analysis of these deposits is necessary to determine the source of the deposits and to find possible ways to avoid or treat them. The late stages of ARM, geographic atrophy, and neovascular (disciform) degeneration, are called age‐related macular degeneration (AMD), and result in severe and irreversible visual impairment. Since there is still no adequate therapy for the majority of people disabled by AMD, and because of the aging population resulting in even more patients with this disease, it is necessary to intensify the research on ARM in order to prevent AMD or find a therapy for it. Microsc Res Tech 36:106–122, 1997.

The APO*E3-Leiden mouse as an animal model for basal laminar deposit

AIM To investigate the APO*E3-Leiden mouse as an animal model for age related maculopathy (ARM) related extracellular deposits. METHODS Eyes were obtained from APO*E3-Leiden transgenic mice on a high fat/cholesterol (HFC) diet (n=12) or on a normal mouse chow (n=6), for 9 months. As controls, eyes were collected from APO-E knockout mice on the same diets. From each mouse one eye was processed for microscopic evaluation and immunohistochemistry with a polyclonal antibody directed against human apo-E. Electron microscopy was also performed. RESULTS All 12 eyes of the APO*E3-Leiden mice on an HFC diet contained basal laminar deposit (BLD; class 1 to class 3), whereas two of six APO*E3-Leiden mice on normal chow showed BLD class 1. The ultrastructural aspects of this BLD were comparable with those seen in early BLD in humans, and BLD showed immunoreaction with anti-human-apo-E antibodies. No BLD was found in any of the control mice. Drusen were not detected in any of the mice. CONCLUSION These results indicate that APO*E3-Leiden mice can be used as animal model for the pathogenesis of BLD, and that a HFC diet enhances the accumulation of this deposit. Furthermore, this study supports the previously suggested involvement of dysfunctional apo-E in the accumulation of extracellular deposits in ARM.

Ocular melanoma in families with dysplastic nevus syndrome

Five families with the dysplastic nevus syndrome, in each of which one member had ocular melanoma, are reported. These five families were examined within a 3-year period in one medical center. To date only five other families with such a combination have been reported. We suggest a causal relation between ocular melanoma and the familial dysplastic nevus syndrome.