AAV-mediated and pharmacological induction of Hsp70 expression stimulates survival of retinal ganglion cells following axonal injury.

We evaluated the effect of AAV2- and 17-AAG (17-N-allylamino-17-demethoxygeldanamycin)-mediated upregulation of Hsp70 expression on the survival of retinal ganglion cells (RGCs) injured by optic nerve crush (ONC). AAV2-Hsp70 expression in the retina was primarily observed in the ganglion cell layer. Approximately 75% of all transfected cells were RGCs. RGC survival in AAV2-Hsp70-injected animals was increased by an average of 110% 2 weeks after the axonal injury compared with the control. The increase in cell numbers was not even across the retinas with a maximum effect of approximately 306% observed in the inferior quadrant. 17-AAG-mediated induction of Hsp70 expression has been associated with cell protection in various models of neurodegenerative diseases. We show here that a single intravitreal injection of 17-AAG (0.2 ug ul(-1)) results in an increased survival of ONC-injured RGCs by approximately 49% compared with the vehicle-treated animals. Expression of Hsp70 in retinas of 17-AAG-treated animals was upregulated approximately by twofold compared with control animals. Our data support the idea that the upregulation of Hsp70 has a beneficial effect on the survival of injured RGCs, and the induction of this protein could be viewed as a potential neuroprotective strategy for optic neuropathies.

The effects of Helicobacter pylori infection on intraocular pressure in anterior uveitis.

PURPOSE: We investigated the influence of H. pylori infection on intraocular pressure (IOP) in anterior uveitis patients to clarify whether H. pylori infection is related to high IOP in anterior uveitis. METHODS: In this prospective study, 165 Korean anterior uveitis patients were examined. All patients underwent serological analysis to identify the cause of uveitis, including the presence of H. pylori infection by enzyme-linked immunosorbent assay. Serological values were compared between patients with and without high IOP. RESULTS: Seropositivity for H. pylori was 69.70% of patients with high IOP and 38.38% of patients with normal IOP (P<0.01). CONCLUSION: This study suggests that H. pylori infection is associated with high IOP in anterior uveitis.

Comparison of long-term surgical success of Ahmed Valve implant versus trabeculectomy in open-angle glaucoma.

AIM: To compare the long-term intraocular pressure (IOP) outcomes of Ahmed Glaucoma Valve (AGV) implantation to trabeculectomy with mitomycin C (MMC) in open-angle glaucoma (OAG). METHODS: 78 OAG patients who underwent AGV implantation were matched with respect to age, preoperative surgery, preoperative IOP and preoperative medicines to 88 OAG patients who underwent trabeculectomy with MMC with a minimum of 3 years' follow-up. The cumulative probability of success between the two groups with different criteria was analysed: (1) an IOP < or =21 mm Hg and a reduction of IOP>/=15% from baseline; and (2) an IOP < or =18 mm Hg and a reduction of IOP > or =20% from baseline. No loss of light perception, no additional glaucoma surgery and no hypotony were also required. RESULTS: The 5-year cumulative probability of success was not statistically significant between eyes that had an AGV or trabeculectomy with MMC when success was defined as criteria A (p = 0.094). However, when success was defined according to criteria B, eyes undergoing trabeculectomy with MMC had a higher rate of success (p = 0.024). CONCLUSIONS: Trabeculectomy with MMC has a significantly higher 5-year cumulative probability of success compared with AGV implants when greater reduction IOP is necessary.

Redox proteins thioredoxin 1 and thioredoxin 2 support retinal ganglion cell survival in experimental glaucoma.

We investigated the neuroprotective effect of thioredoxin 1 (Trx1) and thioredoxin 2 (Trx2) which play critical roles in the regulation of oxidative stress on retinal ganglion cells (RGCs) in a rat glaucoma model. Expression of Trx1 and Trx2 and Trx-interacting protein (Txnip) was observed in the RGC layer (GCL), nerve fiber layer and inner nuclear layer. Txnip-, Trx1- and Trx2-expressing cells in the GCL were primarily colocalized with RGCs. The increased Txnip protein level was observed 2 and 5 weeks after glaucoma induction. Trx1 level decreased 2 weeks after glaucoma induction and more prominently after 5 weeks. No change in Trx2 levels was detected. The effects of Trx1 and Trx2 overexpression on RGC survival were evaluated 5 weeks after glaucoma induction. In nontransfected and EGFP-transfected (used as a negative control) retinas, RGC loss was approximately 27% compared with control. The loss of RGCs in Trx1- and Trx2- transfected retinas was approximately 15 and 17%, respectively. Thus, Trx1 and Trx2 preserved 45 and 37% of cells, respectively that were destined to die in glaucomatous retinas. The results of this study provide evidence for the involvement of oxidative stress in RGC degeneration in experimental glaucoma and point to potential strategies to reduce its impact.

Genetic analysis of the complement factor H related 5 gene in haemolytic uraemic syndrome.

Several mutations in the CFH gene have been described in non-Shiga-toxin-associated haemolytic uraemic syndrome (non-Stx-HUS), a rare syndrome characterized by haemolytic anaemia, thrombocytopenia and acute renal failure. Mutations in genes encoding other complement regulatory proteins, membrane cofactor protein (CD46) and complement factor I (CFI), were also involved in the pathogenesis of the disease. Anyway, mutations in the three genes account for no more than 50% of cases of non-Stx-HUS. Human complement factor H related 5 (CFHR5) is a recently characterised member of the human complement factor H (CFH) family that has been found as a component of immune deposits in human kidney with sclerotic lesions from different causes. CFHR5 possesses cofactor activity and has been proposed to play a role in complement regulation in the glomerulus. We screened CFHR5 gene for variations potentially involved in the aetiology of HUS. Forty-five patients with HUS and 80 controls were analysed. Altogether, 5 genetic variants in CFHR5 were found in overall 9/45 HUS patients and in 4/80 controls. Statistical analysis showed that allelic variants in CFHR5 were prefentially associated with HUS. Based on these data, we conclude that, though not causative, CFHR5 genetic alterations may play a secondary role in the pathogenesis of HUS.

Intermediate-term comparison of trabeculectomy with intraoperative mitomycin-C between Asian American and Caucasian glaucoma patients: a case-controlled comparison.

PURPOSE: Compare the efficacy and survival of trabeculectomy with intraoperative mitomycin-C (MMC) between Asian American and Caucasian patients in the same clinical setting. METHODS: In total, 29 Asian American patients (29 eyes) with trabeculectomies were matched case to case with 29 Caucasian patients (29 eyes) retrospectively. Matching criteria included age, glaucoma subtype, and preoperative intraocular pressure (IOP), gender, surgeon, ocular history, and glaucoma medications. Criteria of success included: (1) Final IOP>5 and <22 mmHg, (2) IOP reduction>or=20%, or final IOP

Trabeculectomy and optic nerve head topography.

The objective of the present study was to evaluate changes in optic nerve head parameters, measured by confocal laser tomography, before and after trabeculectomy in order to identify outcome measures for the management of glaucoma. The optic nerve head of 22 eyes (22 patients) was analyzed by confocal laser tomography with the Heidelberg retinal tomogram (HRT) before and after trabeculectomy. The median time between the first HRT and surgery was 4.6 months (mean: 7.7 +/- 8.3) and the median time between surgery and the second HRT was 10.8 months (mean: 12.0 +/- 6.8). The patients were divided into two groups, i.e., those with the highest (group A) and lowest (group B) intraocular pressure (IOP) change after surgery. Differences in the 12 standard topographic parameters before and after surgery for each group were evaluated by the Wilcoxon signed rank test and the differences in these parameters between the two groups were compared by the Mann-Whitney rank sum test. Multiple regression analysis was used to evaluate the influence of the change in IOP (DeltaIOP and DeltaIOP%) and the changes in the other parameters. There were significant differences in the HRT measures before and after surgery in group A only for cup volume. In group B, no parameter was statistically different. The changes in group A were not significantly different than those in group B for any parameter (P > 0.004, Bonferroni correction for multiple comparisons). DeltaIOP and DeltaIOP% had a statistically significant effect on Delta cup disk area, Delta cup volume and Delta mean cup depth. Changes in cup shape size were influenced significantly only by DeltaIOP. Some optic disc parameters measured by HRT presented a significant improvement after filtering surgery, depending on the amount of IOP reduction. Long-term studies are needed to determine the usefulness of these findings as outcome measures in the management of glaucoma.

Trabeculectomy and optic nerve head topography

The objective of the present study was to evaluate changes in optic nerve head parameters, measured by confocal laser tomography, before and after trabeculectomy in order to identify outcome measures for the management of glaucoma. The optic nerve head of 22 eyes (22 patients) was analyzed by confocal laser tomography with the Heidelberg retinal tomogram (HRT) before and after trabeculectomy. The median time between the first HRT and surgery was 4.6 months (mean: 7.7 ± 8.3) and the median time between surgery and the second HRT was 10.8 months (mean: 12.0 ± 6.8). The patients were divided into two groups, i.e., those with the highest (group A) and lowest (group B) intraocular pressure (IOP) change after surgery. Differences in the 12 standard topographic parameters before and after surgery for each group were evaluated by the Wilcoxon signed rank test and the differences in these parameters between the two groups were compared by the Mann-Whitney rank sum test. Multiple regression analysis was used to evaluate the influence of the change in IOP (deltaIOP and deltaIOP percent) and the changes in the other parameters. There were significant differences in the HRT measures before and after surgery in group A only for cup volume. In group B, no parameter was statistically different. The changes in group A were not significantly different than those in group B for any parameter (P > 0.004, Bonferroni correction for multiple comparisons). deltaIOP and deltaIOP percent had a statistically significant effect on delta cup disk area, delta cup volume and delta mean cup depth. Changes in cup shape size were influenced significantly only by deltaIOP. Some optic disc parameters measured by HRT presented a significant improvement after filtering surgery, depending on the amount of IOP reduction. Long-term studies are needed to determine the usefulness of these findings as outcome measures in the management of glaucoma.

Effects of combined cataract surgery and trabeculectomy with mitomycin C on ocular dimensions.

AIMS: To characterise changes in ocular dimensions after combined cataract operation and trabeculectomy with mitomycin C using separate incisions (combined operation). METHODS: 24 consecutive eyes that had combined operation and 16 eyes that had cataract operation alone were enrolled. The axial lengths before and after operations were determined with non-contact optical coherence biometry. The intraocular pressures (IOP), axial lengths, corneal curvatures, and the expected and observed refractive errors before and after operations were compared. RESULTS: After a combined operation, mean IOP was significantly reduced from 16.6 (SD 5.8) mm Hg to 10.9 (4.1) mm Hg (p<0.00001), and mean axial length was significantly shortened from 24.10 (0.98) mm to 23.98 (0.96) mm (p<0.00001). The mean axial length reduction after combined operation (117 (57) microm) was significantly larger than the reduction after cataract operation alone (75 (38) microm, p<0.02), and correlated significantly with the postoperative IOP (p<0.002). There was a mean with the rule surgically induced corneal astigmatism of 0.44 (0.83) dioptre by vector analysis, and a significant increase of mean keratometry reading of 0.23 (0.46) dioptre after a combined operation. However, there was no significant difference between the expected and observed refractive errors. CONCLUSIONS: Despite an alteration of the axial length and corneal curvature, the refractive outcome after a combined operation did not differ significantly from the predicted refraction.

Outcomes of bleb excision and conjunctival advancement for leaking or hypotonous eyes after glaucoma filtering surgery.

AIM: To determine outcomes of bleb excision and conjunctival advancement for leaking or hypotonous eyes after glaucoma filtering surgery. METHODS: In a retrospective case series the medical records of all patients who underwent bleb excision and conjunctival advancement surgery for bleb leaks or hypotony (defined as IOP less than 6 mm Hg, associated with reduced vision) at the Jules Stein Eye Institute and the Yale University Eye Center between January 1993 and June 2002 were reviewed. Only patients with more than 6 months of follow up were included. Complete success was defined as resolution of the pre-existing leak or hypotony, with maintenance of IOP > or =6 and < or =21 mm Hg, in the absence of further glaucoma surgery and without any glaucoma medication. Qualified success met the above criteria with or without the use of glaucoma medications. Success rates were analysed with Kaplan-Meier survival curves. RESULTS: 49 eyes were included in the study; 13 eyes had overt bleb leaks, 27 eyes had hypotony. Nineteen patients underwent resuturing of sclera and/or placement of a pericardial graft in addition to bleb excision and conjunctival advancement. Mean preoperative IOP increased from 3.2 (SD 2.4) mm Hg (range 0-10 mm Hg) to 13.8 (4.8) mm Hg (range 6-29 mm Hg) at last follow up (p<0.0001). Mean preoperative visual acuity improved from 0.6 (0.3) logMAR (range 0-2) to 0.3 (0.3) logMAR (range 0-2) at final follow up (p<0.0001). 16 eyes (40%) were classified as complete success and 17 additional eyes achieved qualified success, for a total of 33 eyes (83%) achieving at least qualified success. There was no significant difference in the rate of complete success (p = 0.95) or qualified success (p = 0.88) between the group of patients who underwent bleb excision and conjunctival advancement alone versus those who also had resuturing of sclera and/or placement of a pericardial graft. Failures included three eyes that had persistent hypotony without leak, requiring additional bleb revision, and four with uncontrolled IOP, two of whom underwent additional glaucoma surgery. CONCLUSION: Bleb excision with conjunctival advancement is a successful procedure for bleb repair. This technique provides successful resolution of leaks and hypotony, maintains glaucoma control with or without medication, and preserves vision with minimal postoperative complications in a majority of eyes.

Serial axial length measurements in congenital glaucoma.

PURPOSE: To illustrate the utility of axial length measurements in the management of congenital glaucoma. METHODS: Interventional case series. Twelve eyes of six consecutive patients with congenital glaucoma were followed with serial axial length measurements. The axial growth patterns were compared with the normal growth curve. RESULTS: Eight (66.7%) of 12 eyes had initial axial lengths longer than the normal range, and 4 eyes (33.3%) were within the normal range. After surgical intervention with good intraocular pressure control in 10 eyes, 3 eyes showed a decrease of axial length and 7 eyes showed no decrease of axial length, but the axial growth pattern paralleled the normal growth curve. After surgical intervention with poor intraocular pressure control, 2 eyes had axial growth pattern greater than the normal pattern. CONCLUSION: With intraocular pressure control in congenital glaucoma, axial length may decrease or the axial growth pattern may parallel the normal growth curve. Axial length measurements may be useful to monitor the control of congenital glaucoma.

Optic disk characteristics before the occurrence of disk hemorrhage in glaucoma patients.

PURPOSE: To evaluate qualitatively the structural characteristics and the associated features that antedate the occurrence of a disk hemorrhage in patients with glaucoma. METHODS: Retrospective observational case series. A total of 4018 pairs of stereoscopic optic disk images obtained over 15 years were reviewed. All eyes with optic disk images before the occurrence of a disk hemorrhage were enrolled. The disk images were evaluated in a masked fashion with respect to the general neural rim and peripapillary appearance. RESULTS: The optic disk characteristics and associated features that most antedate the disk hemorrhage in 33 eyes of 26 patients that had previous optic disk images for evaluation are focal neural rim notch (36%), thin sloping rim (42%), peripapillary atrophy (79%), and superior-inferior rim asymmetry (73%). In eyes with preexisting focal rim notches, all subsequent disk hemorrhages were identified at or adjacent to the notches. CONCLUSIONS: Focal rim notching may precede the occurrence of a disk hemorrhage.

Interobserver variability of optic disk variables measured by confocal scanning laser tomography.

PURPOSE: To assess the interobserver variation of confocal laser scanning tomographic measurements of the optic nerve head and to address the question of whether the addition of clinical optic disk photographs is helpful in outlining the optic disk margin and in reducing the observer-related variation of the measurements. PATIENTS AND METHODS: Optic disk variables for 16 eyes of 16 patients with glaucoma, generated by confocal laser scanning laser tomography (Heidelberg Retina Tomograph), were independently evaluated by four experienced glaucoma specialists, and the interobserver variability was calculated. A second separate review by the same observers included the use of clinical stereoscopic color optic nerve head photographs to aid definition of the optic disk margin. RESULTS: Optic disk parameters with the smallest interobserver variation were cup shape measure, maximum cup depth, height variation contour, and mean height contour. The intraobserver variation of these parameters did not increase when clinical optic disk slides were additionally available. Parameters with the highest interobserver variation were volume below surface, volume below reference, volume above surface, and volume above reference. The observer variation of these optic disk parameters increased significantly for two of the four examiners when clinical optic disk slides were additionally available for outlining the optic disk margin. CONCLUSION: Confocal laser scanning tomography of the optic nerve head can be improved significantly if clinical optic disk photographs are additionally available to help in outlining the optic disk margin. Because interobserver variation in the tomographic optic disk measurements can be significant, even if experienced observer are involved, tomographic optic disk measurements may be centralized in reading centers in the case of multicenter studies.

Induction of heat shock protein 72 protects retinal ganglion cells in a rat glaucoma model.

PURPOSE: To investigate whether heat shock protein (Hsp) 72 is induced in retinal ganglion cells (RGCs) in experimental rat glaucoma and whether the induction of Hsp72 by heat stress or zinc (Zn(2+)) administration can increase survival of RGCs in the model. METHODS: Intraocular pressure (IOP) was elevated unilaterally in Wistar rats with argon laser irradiation of the trabecular meshwork 5 days after intracameral injection of india ink. Immunohistochemical staining for Hsp72 was performed. The rats with elevated IOP were treated with heat stress once a week (six rats) or intraperitoneal injection of zinc (10 mg/kg) every two weeks (six rats). Untreated rats with elevated IOP served as a control group (six rats). Quercetin, an inhibitor of Hsp expression was injected in the rats with heat stress (six rats) and zinc injection (seven rats). Subsequent to 4 weeks of IOP elevation, RGCs were counted. RESULTS: The IOP increase compared with the contralateral eyes was 48% +/- 4% throughout the study period. Hsp72 was detected only in the eyes with elevated IOP at 1 and 2 days and was weakly detected at 1 week of IOP elevation. A single administration of zinc strongly induced Hsp72 in RGCs of rats with elevated IOP for 2 weeks. Treatment with heat stress or zinc in rats with elevated IOP increased RGC survival after 4 weeks of IOP elevation, compared with the untreated control group (P = 0.004, n = 6). Quercetin reversed the positive effect of heat stress or zinc injection on RGC survival. CONCLUSIONS: These results demonstrate the possibility of a novel therapeutic approach to glaucoma through an enhanced induction of the endogenous heat shock response.

Complement factor H and hemolytic uremic syndrome.

Factor H is a 150 kDa single chain plasma glycoprotein that plays a pivotal role in the regulation of the alternative pathway of complement. Primary sequence analysis reveals a structural organization of this plasma protein, in 20 homologous units, called Short Consensus Repeats (SCRs), each about 60 amino acids long. Biochemical and genetic studies show an association between factor H deficiency and human diseases, including Systemic Lupus Erythematosus, susceptibility to pyogenic infection and a form of membranoproliferative glomerulonephropathy. More recently, factor H deficiency has also been associated with susceptibility to Hemolytic Uremic Syndrome (HUS), a disease consisting of microangiopathic hemolytic anemia, thrombocytopenia and acute renal failure, caused by platelet thrombi which mainly, but not exclusively, form in the microcirculation of the kidney. In this review, we summarize recent genetic and biochemical data, which indicate a critical role for factor H in the pathogenesis of HUS and suggest an important role of the most C-terminal domain, i.e. SCR 20, in the disease. In addition, we discuss the physiological consequences of these findings, as novel functional data show a particular essential role of SCR 20 of factor H as the central discriminatory and regulatory site of this multidomain, multifunctional plasma protein.

Ability of peripapillary atrophy parameters to differentiate normal-tension glaucoma from glaucomalike disk.

PURPOSE: To investigate the ability of peripapillary atrophy (PPA) parameters to differentiate normal-tension glaucoma (NTG) from glaucomalike disk (GLD). METHODS: Thirty-three eyes of 33 patients with GLD that had no evidence of visual field defect and retinal nerve fiber layer defect and 33 eyes of 33 patients with NTG, matched with age and intraocular pressure, were enrolled. The participants were selected from the database of patients referred from a routine health checkup because of high cup-to-disk ratio (>0.5). Topographic measurements for the optic disk were performed using the Heidelberg Retina Tomograph (HRT). The extent of PPA (zone beta) was measured with Atrophy Zone Analysis software of HRT. Receiver operating characteristic (ROC) curves (GraphROC version 2.0) were used to compare the new formula including PPA parameters with that of the HRT discriminant analysis formula in differentiating NTG from GLD. RESULTS: The area of zone beta, atrophy-to-disk area ratio, and angular and radial extent of zone beta were significantly larger in NTG (P < 0.01). Multiple logistic regression analysis showed that rim area and corrected radial extent of zone beta are variables that show significant difference between NTG and GLD (P < 0.05). The area under the ROC curve for the new formula including rim area and corrected radial extent of zone beta (0.8655) was significantly larger than that for the HRT discriminant analysis formula (0.7351) (P = 0.0128). CONCLUSION: The PPA measurement obtained by HRT can be a useful additional tool to differentiate NTG from GLD after the first screening by disk photograph in a routine health checkup.