Newly Identified Chemicals Preserve Mitochondrial Capacity and Decelerate Loss of Photoreceptor Cells in Murine Retinal Degeneration Models.

Purpose: Metabolic stress and associated mitochondrial dysfunction are implicated in retinal degeneration irrespective of the underlying cause. We identified seven unique chemicals from a Chembridge DiverSET screen and tested their protection against photoreceptor cell death in cell- and animal-based approaches. Methods: Calcium overload (A23187) was triggered in 661W murine photoreceptor-derived cells, and changes in redox potential and real-time changes in cellular metabolism were assessed using the MTT and Seahorse Biosciences XF assay, respectively. Cheminformatics to compare structures, and biodistribution in the living pig eye aided in selection of the lead compound. In-situ, retinal organ cultures of rd1 mouse and S334ter-line-3 rat were tested, in-vivo the light-induced retinal degeneration in albino Balb/c mice was used, assessing photoreceptor cell numbers histologically. Results: Of the seven chemicals, six were protective against A23187- and IBMX-induced loss of mitochondrial capacity, as measured by viability and respirometry in 661W cells. Cheminformatic analyses identified a unique pharmacophore with 6 physico-chemical features based on two compounds (CB11 and CB12). The protective efficacy of CB11 was further shown by reducing photoreceptor cell loss in retinal explants from two retinitis pigmentosa rodent models. Using eye drops, CB11 targeting to the pig retina was confirmed. The same eye drops decreased photoreceptor cell loss in light-stressed Balb/c mice. Conclusions: New chemicals were identified that protect from mitochondrial damage and lead to improved mitochondrial function. Using ex-vivo and in-vivo models, CB11 decreased the loss of photoreceptor cells in murine models of retinal degeneration and may be effective as treatment for different retinal dystrophies.

Corneal perforation in undiagnosed Sjögren's syndrome following topical NSAID and steroid drops post routine cataract extraction.

A 74-year-old man presented with a progressive decrease in visual acuity and foreign body sensation in his right eye 8 days post uncomplicated phacoemulsification cataract surgery and intraocular lens insertion. The patient had been placed on a perioperative cataract regimen which consisted of G. Maxitrol (dexamethasone, polymyxin B sulfate, neomycin sulfate) four times a day and G. Yellox twice daily (bromfenac, a non-steroidal anti-inflammatory) for 2 weeks. On examination, he had a corneal ulcer and stromal thinning in his right eye which progressed to a full thickness perforation 12 hours later. The patient required a full thickness tectonic corneal transplant. Direct questioning revealed that this patient had both dry mouth and eyes. Serology revealed that the patient was positive for rheumatoid factor and for anti-Ro and anti-La antibodies. A parotid gland biopsy revealed significant lymphocytic infiltrate consistent with Sjögren's syndrome.

Calpain 10 homology modeling with CYGAK and increased lipophilicity leads to greater potency and efficacy in cells.

Calpain 10 is a ubiquitously expressed mitochondrial and cytosolic Ca(2+)-regulated cysteine protease in which overexpression or knockdown leads to mitochondrial dysfunction and cell death. We previously identified a potent and specific calpain 10 peptide inhibitor (CYGAK), but it was not efficacious in cells. Therefore, we created a homology model using the calpain 10 amino acid sequence and calpain 1 3-D structure and docked CYGAK in the active site. Using this model we modified the inhibitor to improve potency 2-fold (CYGAbuK). To increase cellular efficacy, we created CYGAK-S-phenyl-oleic acid heterodimers. Using renal mitochondrial matrix CYGAK, CYGAK-OC, and CYGAK-ON had IC(50)'s of 70, 90, and 875 nM, respectively. Using isolated whole renal mitochondria CYGAK, CYGAK-OC, and CYGAK-ON had IC(50)'s of 95, 196, and >10,000 nM, respectively. Using renal proximal tubular cells (RPTC) in primary culture, 30 min exposures to CYGAK-OC and CYGAbuK-OC decreased cellular calpain activity approximately 20% at 1 µM, and concentrations up to 100 µM had no additional effect. RPTC treated with 10 µM CYGAK-OC for 24 h induced accumulation of ATP synthase ß and NDUFB8, two calpain 10 substrates. In summary, we used molecular modeling to improve the potency of CYGAK, while creating CYGAK-oleic acid heterodimers to improve efficacy in cells. Since calpain 10 has been implicated in type 2 diabetes and renal aging, the use of this inhibitor may contribute to elucidating the role of calpain 10 in these and other diseases.

Cataract surgery in the first year of life: aphakic glaucoma and visual outcomes.

OBJECTIVE: To report the incidence of aphakic glaucoma following lensectomy in infants in their first year of life and examine the impact of this diagnosis on visual outcome. DESIGN: Retrospective cohort study. PARTICIPANTS: All patients who had lensectomy for congenital cataract during the first year of life at British Columbia Children's Hospital between 1995 and 2006. METHODS: Retrospective review of medical records. RESULTS: Seventy-five eyes of 46 patients (29 bilateral, 17 unilateral) were included. The mean age at lensectomy was 93 days (range, 2-364 days) with a mean follow-up of 77.5 months (range, 36-166 months). Patients with bilateral cataracts had a better visual outcome than those with unilateral cataracts (p < 0.032). Of the patients with measurable visual acuity (VA), 34 of 45 eyes (75.6%) with bilateral cataracts and only 3 of 16 eyes (18.8%) with unilateral cataract achieved a VA of 20/40 or better. Eighteen of 75 eyes (24%) developed aphakic glaucoma at a mean of 30 months following lensectomy. Nine patients (50%) achieved final vision of 20/40 or better. The development of aphakic glaucoma was not associated with worse visual outcomes (p < 0.315). The mean intraocular pressure (IOP) at diagnosis was 28.6±5.9 mm Hg and mean final IOP was 14.1 ± 3.0 mm Hg, a significant reduction (p < 0.0001). Fifteen of 18 eyes with aphakic glaucoma (83.3%) required surgical intervention to achieve IOP control. CONCLUSIONS: Children with aphakic glaucoma may have good visual outcomes if it is recognized early and managed appropriately. A significant proportion of patients required surgical intervention to control IOP.

Short-term safety and efficacy of intravitreal triamcinolone acetonide for uveitic macular edema in children.

OBJECTIVES: To evaluate the short-term safety and efficacy of intravitreal (IV) triamcinolone acetonide (TA) for treating pediatric cystoid macular edema (CME) secondary to noninfectious uveitis. METHODS: A retrospective noncomparative interventional case series. The medical records of 15 consecutive children (16 eyes) with uveitic CME treated with IVTA (2 or 4 mg) were reviewed. Data collected included details of uveitis, CME, visual acuity, intraocular pressure, and cataract development. The median follow-up time was 16 months (range, 9-36 months). RESULTS: Resolution of CME was achieved in all of the treated eyes. The median time taken for CME to resolve was 3 weeks (range, 1-24 weeks). The mean improvement of visual acuity after IVTA was 0.6 logarithm of the minimum angle of resolution. Following initial response to IVTA, CME relapsed in 5 eyes (31%) after a median time of 7 months (range, 3-13 months). The most common adverse effect was increased intraocular pressure, with an increase of more than 15 mm Hg in 5 eyes (31%). Steroid-induced cataract was observed in 6 of 11 phakic eyes (55%). CONCLUSIONS: We found that IVTA is efficacious in the treatment of uveitic CME in children and results in CME resolution and visual acuity improvement. As in adults, treatment in children may be associated with elevated intraocular pressure and cataract.

Strabismus in adults with uveal melanoma following episcleral plaque brachytherapy.

PURPOSE: To ascertain the incidence of persistent strabismus in patients treated with plaque brachytherapy and its subsequent treatment. METHODS: A single center retrospective case note review of adult patients with persistent diplopia or strabismus following plaque brachytherapy for all types of intraocular tumors between 1996 and 2004. RESULTS: A total of 929 consecutive adults underwent plaque brachytherapy during the study period at a single center. Sixteen patients (1.7%) with treated uveal melanoma developed persistent diplopia or strabismus. In 11 patients (69%) the timing of onset was in the first year, in 2 (13%) in the second year, and one each (6% each) in years 5, 7, and 8. Two patients (13%) did not require any intervention. Fourteen patients (88%) required treatment: 7 (50%) were treated with prisms only, 3 (21%) underwent botulinum toxin (BTXA) injections, and 4 (29%) were treated with extraocular muscle surgery (3 required one operation and one required 2 procedures). CONCLUSIONS: The incidence of ocular motility disorders following plaque brachytherapy in our cohort was 1.7% over 8 years and we include this in the consent process for conservative treatment of intraocular tumors. Options for treatment for persistent diplopia or strabismus include prisms, botulinum toxin injection, or surgery.

Effect of administration of CTLA4-Ig as protein or cDNA on corneal allograft survival.

PURPOSE: To examine the role of the CD28-CD80-CD86 pathway of T-lymphocyte costimulation in corneal allograft rejection and the effect of blockade of that pathway on graft survival. METHODS: Kinetics of CD80 and CD86 expression in the cornea and draining lymph nodes were examined by RT-PCR and immunohistochemistry in untreated allograft recipients in a high-responder rat model. The effect of blockade of CD28-mediated costimulation was first examined by ex vivo incubation of excised Brown Norway rat donor cornea with the inhibitory protein CTLA4-Ig or an adenovirus vector (AdCTLA) expressing CTLA4-Ig, before grafting into Lewis rat recipients. A second group of graft recipients received systemic posttransplantation treatment with either CTLA4-Ig or AdCTLA. RESULTS: Expression of CD80 mRNA was increased in both donor and recipient cornea 16 hours after transplantation, whereas CD86 was detected constitutively, with no significant early increase. Immunohistochemistry on day 5 after transplantation demonstrated major histocompatibility complex (MHC) class II expression, no CD80, and only a trace of CD86 in corneal allografts. In lymph nodes strong MHC class II, weak CD80, and moderate CD86 expression was noted. Both donor cornea and recipient treatment with CTLA4-Ig resulted in prolonged allograft survival. AdCTLA was found to induce sustained secretion of bioactive CTLA4-Ig from corneas infected ex vivo. Survival of corneal allografts incubated with AdCTLA was marginally prolonged, and systemic treatment with AdCTLA significantly prolonged survival. CONCLUSIONS: Protein- or gene-based administration of CTLA4-Ig prolongs allograft survival by treatment of either the recipient or the donor tissue ex vivo before grafting.