Phacoanaphylaxis in Behçet's disease: a clinicopathologic and immunohistochemical study.

PURPOSE: To describe the occurrence of phacoanaphylaxis in enucleated eyes of patients with Behçet's disease. DESIGN: Retrospective, observational, case series and human tissue study. PARTICIPANTS: Twenty-six patients with Behçet's disease who underwent enucleation. METHODS: Histopathologic analysis was performed on 28 enucleated eyes of 26 patients with Behçet's disease. The eyes were divided into two groups, based on the absence or presence of tractional retinal detachment associated with cyclitic membrane formation. Selected eyes with tractional retinal detachment were stained for immunohistochemical examination. MAIN OUTCOME MEASURES: Histopathologic examination of enucleated eyes, including routine histopathologic and immunohistochemical studies. RESULTS: None of the five eyes without retinal detachment showed phacoanaphylaxis. Nine of the 23 eyes with detachment exhibited phacoanaphylaxis, 10 showed no inflammation of the lens, and four were aphakic. There was marked inflammatory cell infiltration in the cyclitic membrane of all nine eyes with phacoanaphylaxis. Immunohistochemical examination demonstrated positive staining for the macrophage markers in the epithelioid and giant cells. The average interval between onset of the ocular manifestations of Behçet's disease and enucleation was 63 months for eyes with phacoanaphylaxis and 35 months for eyes without phacoanaphylaxis (P<0.005). CONCLUSIONS: In Behçet's disease, eyes with long-standing intraocular inflammation complicated by cyclitic membrane formation may develop phacoanaphylaxis. Such patients may benefit from surgical removal of the cyclitic membrane along with the lens in eyes with significant visual function.

Critical role of photoreceptor apoptosis in functional damage after retinal detachment.

PURPOSE: Although apoptosis is assumed to play a pivotal role in retinal function loss, its mechanism and real influence on retinal function are still unclear. To investigate the relation between retinal function and apoptosis, we studied photoreceptor apoptosis in experimental retinal detachment (RD). METHODS: We induced RD by subretinal injection of sodium hyaluronate in Brown Norway rats. Apoptotic photoreceptors were detected by TdT-dUTP Terminal Nick-End Labeling (TUNEL). To evaluate the function of the detached retina, electroretinograms (ERGs) were taken on day 1, 3 with corneal electrodes and full-field stimulation. RESULTS: Apoptotic DNA fragmentation appeared 12 hours after RD, was most prominent on day 3, and decreased thereafter. The ERGs showed that the amplitudes of dark-adapted a-waves and light adapted 2 Hz b-waves decreased immediately after RD and continued to decrease over time. The administration of Fas/Fc chimera recombinant protein or a caspase inhibitor, Z-VAD.fmk, failed to prevent either photoreceptor apoptosis or retinal functional damage. In contrast, brain derived neurotrophic factor (BDNF) and basic fibroblast growth factor (bFGF) significantly impeded both apoptosis and dysfunction. The ERGs recognized the functional changes sensitively, and these ERG changes correlated well to the amount of photoreceptor apoptosis. Immunohistochemical study showed that apoptosis-inducing factor (AIF), a novel caspase-independent apoptotic factor, was relocalized from mitochondria to the nucleus in this process. CONCLUSIONS: The present results showed that apoptosis was a key phenomenon in the retinal dysfunction in RD and that this process was transmitted mainly by mitochondria-dependent pathways rather than Fas/Fas-L or downstream caspase dependent pathways.

Recombinant Sendai virus-mediated gene transfer into adult rat retinal tissue: efficient gene transfer by brief exposure.

To determine the usefulness of recombinant Sendai virus (SeV) for ocular gene transfer, the authors characterized SeV-mediated gene transfer to the retinal tissue of adult rats via subretinal injection. Recombinant SeV encoding the lacZ gene achieved frequent transgene expression in the retinal pigment epithelium (RPE) (mean=38.76%), while gene transfer to other retinal cells was rare. These findings are similar to those of previous reports using adenoviruses. Peak reporter gene expression of SeV in cultured RPE cells was similar to that of adenovirus at the same titer; however, SeV achieved high levels of expression after a brief vector-cell contact time, while adenovirus required over 3hr for efficient gene transfer. This finding was also observed in vivo following a brief SeV filling in the subretinal space, and may therefore provide a clinical advantage in avoiding retinal damage due to prolonged detachment. The observed SeV-mediated gene expression in the rat retina was transient. The initial phase of the decrease in luciferase activity could be prevented by daily eye drops of dexamethasone, suggesting that the corticosteroid-sensitive host reaction may affect early clearance of the virus. The late decline of transgene expression (2 weeks) was inhibited by the immunosuppressant, cyclosporin A, in a dose-dependent manner, suggesting that the cytotoxic T-lymphocyte response may be important in this phase. This work represents the first report of SeV-mediated gene transfer to ocular tissue, and identifies recombinant SeV as a new tool for studies of retinal gene transfer and gene therapy.

Neovascularization in the anterior segment of the rabbit eye by experimental anterior ischemia.

PURPOSE: To investigate the effects of anterior ischemia accompanied by neither retinal nor choroidal ischemia on the anterior segment of the eye. METHODS: Both long posterior ciliary arteries in the right eye of 14 rabbits were directly cauterized with an electric coagulator. The eyes were enucleated 1, 2, 4, 7, 9 or 14 days after cauterization, then fixed with 4% paraformaldehyde. Semi-thin sections were studied by light microscopy. Several sections were stained with Griffonia simplicifolia lectin, which bound specifically to mammalian vascular endothelium. Other specimens were examined immunohistochemically for vascular endothelial growth factor (VEGF) protein. The tissue specimens of the first postoperative day were studied for expression of VEGF mRNA by in situ hybridization. RESULTS: Atrophy of the iris and ciliary body was seen after the second postoperative day. Corneal neovascularization appeared after 7 days. Neovascularization on the anterior surface of the iris and in the trabecular meshwork was detected after the ninth postoperative day. The proliferative tissues with newly formed vessels obstructed the iridocorneal angle 14 days after the treatment. There was no histological change in either the retina or choroid. Immunohistochemically, VEGF protein was detected in the epithelial and vascular cells of the iris on the first and fourth postoperative day. Expression of VEGF mRNA was detected in the epithelial cells of the ciliary body on the day following the treatment. CONCLUSIONS: Anterior segment ischemia, when unaccompanied by retinal ischemia, causes neovascularization in the cornea, iris and trabecular tissue.

Re-worsening factor after successful vitrectomy for diabetic retinopathy: optic disc fibrovascular proliferation and macular disease.

PURPOSE: To investigate the factors that influence the visual-changing pattern in proliferative diabetic retinopathy even after successful vitrectomy. METHODS: One hundred and forty-seven consecutive eyes were retrospectively reviewed for 6-48 (average 20) months, and were divided into the following 4 groups based on their changing pattern of vision: group A, the visual acuity improved postoperatively and maintained the maximal corrected vision throughout the observation period (n = 49); group B, the visual acuity improved postoperatively but deteriorated thereafter (n = 68); group C, the visual acuity remained the same as before operation (n = 17), and group D, the visual acuity deteriorated immediately after vitrectomy (n = 13). Various issues including systemic conditions, blood tests, preoperative ocular findings, the operative procedures and postoperative complications were reviewed based on the patient records. These issues were analyzed by Spearman's rank correlation, chi(2) test, an analysis of variance (ANOVA) and the Kruskal-Wallis test. Finally, the discriminate factors between groups A and B were examined by a stepwise logistic regression analysis. RESULTS: The following tendencies were observed in all 4 groups: younger patients tended to show a better visual-changing pattern (p = 0.02); patients with younger age at diabetes onset had a better visual-changing pattern after vitrectomy (p = 0.001), and a lower hemoglobin (Hb) A1c level is associated with a better visual changing pattern (p = 0.017). Preoperative rubeosis and macular detachment were frequently found in groups C and D, as well as postoperative rubeosis, vitreous bleeding and retinal detachment. Finally, a stepwise logistic regression analysis showed both fibrovascular proliferation (p = 0.016) from the optic disc and postoperative macular disease (p = 0.0009) to be significant factors for differentiating group A from group B. CONCLUSIONS: In addition to the factors which have already been indicated to affect the visual outcome of a vitrectomy, preoperative findings such as optic disc fibrovascular proliferation and postoperative macular disease were found to affect the visual-changing pattern after a successful vitrectomy. The optimal timing of surgery is very important not only in order to obtain good visual acuity but also to maintain good vision even after a successful vitrectomy.