Volume 6, Number 43
Monday, October 30, 2006



In this issue: (click heading to view article)
Intraocular Lens Material and Acute Endophthalmitis After Cataract Surgery
Phaco-Viscocanalostomy vs. Phaco-Trabeculotomy
Gene Encoding Receptor Associated with Type I Diabetic Nephropathy, Retinopathy
Atherosclerosis, C-Reactive Protein and Risk for Open-Angle Glaucoma
Briefly











Intraocular Lens Material and Acute Endophthalmitis After Cataract Surgery

Researchers at France’s University of Lyon investigated the causal relationship between acute postoperative endophthalmitis (POE) after cataract surgery and the biomaterial properties of the intraocular lens (IOLs) implanted.

The retrospective cohort study included all patients who had undergone cataract surgery with IOL implantation at the Lyon Croix-Rousse University Hospital between January 1, 1994, and December 31, 2004. Details respecting the type of IOL implanted (material and manufacturer) were meticulously recorded. Researchers documented the number of patients presenting with POE within six weeks of cataract surgery, together with their medical characteristics. The data were then compared, and Fisher"s exact test was used to establish the significance of any apparent associations.

Eight of the 5,837 eyes in the study manifested acute POE (0.14 percent). Seven of these IOLs were composed of polymethylmethacrylate (PMMA) and one of heparinized PMMA. Patients with PMMA IOLs carried a higher risk of developing POE than did those implanted with heparinized PMMA, hydrophilic acrylic or hydrophobic acrylic IOLs.

The investigators concluded that the incidence of acute POE after cataract surgery in their hospital was similar to that currently reported for other institutions in developed countries. They maintain that their results add further evidence that IOL material and type are factors contributing to the risk to develop an acute POE after cataract surgery.

SOURCE: Kodjikian L, Beby F, Rabilloud M, et al. Influence of intraocular lens material on the development of acute endophthalmitis after cataract surgery. Eye 2006; Sep 15 [Epub ahead of print]. 		Table of Contents











Phaco-Viscocanalostomy vs. Phaco-Trabeculotomy

Investigators at Japan’s Sensho-kai Eye Institute in Kyoto compared the surgical outcomes between phaco-viscocanalostomy and phaco-trabeculotomy in patients with open-angle glaucoma (OAG).

In a nonrandomized, retrospective clinical study, 110 eyes underwent phaco-viscocanalostomy (VCS group) and 110 eyes underwent phaco-trabeculotomy (LOT group). The mean follow-up was 857+/- 409 (+/-SD) days.

The mean preoperative treated intraocular pressure (IOP) values were 20.2 +/- 3.5 mmHg in the VCS group and 20.9 +/- 3.5 mmHg in the LOT group. The postoperative IOPs in the VCS group were 15.0 +/- 3.0 mmHg at one year and 16.1 +/- 3.0 mmHg at three years; in the LOT group the postoperative IOPs were 16.3 +/- 2.9 mmHg at one year and 16.5 +/- 3.3 mmHg at three years. The number of medications used in the VCS group was significantly lower than in the LOT group during the observation periods. The probabilities of achieving IOPs of 21 mmHg or lower at three years in the VCS group were 92.0 percent with or without mediations and 58.2 percent without medications, and they were significantly better than those of the LOT group. The probabilities of achieving IOPs 16 mmHg or lower at three years in the VCS group were 30.5 percent with or without mediations and 30.3 percent without medications, whereas those in the LOT group were 27.5 percent with or without mediations and 19.4 percent without medications. The visual outcome was similar between the groups. Postoperative hyphema (2 mm or greater) and IOP spikes (30 mmHg or higher) occurred significantly less frequently in the VCS group (2.7 percent frequency for hyphema and 3.6 percent frequency for IOP spikes) than in the LOT group (26.4 percent frequency for hyphema and 28.2 percent frequency for IOP spikes). In 13 eyes (11.8 percent) of the LOT group, the highest IOP level was recorded at 40 mmHg or higher. Vitreous hemorrhage occurred once in the LOT group, as did central visual loss.

The authors concluded that after a middle-term observation, phaco-viscocanalostomy provides better IOP control and a lower incidence of vision-threatening complications than phaco-trabeculotomy.

SOURCE: Park M, Hayashi K, Takahashi H, et al. Phaco-viscocanalostomy versus phaco-trabeculotomy: A middle-term study. J Glaucoma 2006;15(5):456-61.		 Table of Contents





Gene Encoding Receptor Associated with Type I Diabetic Nephropathy, Retinopathy

The receptor for advanced glycation end products (RAGE) is considered mainly an intracellular signal-transducer or pro-inflammatory peptide of possible importance in inflammatory and autoimmune diseases. Swedish investigators aimed to determine whether a polymorphism in the gene encoding RAGE (advanced glycosylation end product-specific receptor, AGER) is associated with diabetes type and presence of diabetic complications.

The AGER polymorphism was genotyped in 867 patients with Type I diabetes, 2,467 patients with Type II diabetes and 205 nondiabetic control subjects; all patients were of Scandinavian origin. Results showed that the AGER polymorphism was related to differing genotypes and the presence of diabetic complications. Type I diabetic patients had a higher frequency of the AGER -374 A/A or T/A genotypes than did Type II diabetic patients (51.1 percent vs. 44.9 percent) and control subjects (51.1 percent vs. 47.6 percent). The RAGE -374 T/A polymorphism was associated with HLA-DQB1 genotypes; patients with HLA risk genotypes had a higher frequency of the A/A or T/A genotypes than patients with other HLA-DQB1 genotypes (60.3 percent vs. 40.3 percent). In the Type I diabetes group, the frequency of the A/A or T/A genotypes was higher in patients with diabetic nephropathy than without (61.1 percent vs. 46.8 percent) and higher in patients with sight-threatening retinopathy than in those without (56.1 percent vs. 47.6 percent). In the Type II diabetes group, in those with HbA(1c) values below the median, the T/T genotype was more frequent in those with nephropathy than in those without (54.3 percent vs. 38.2 percent).

The researchers concluded that an HLA-DQB1-dependent association exists between the AGER -374 T/A polymorphism and Type I diabetes. The polymorphism appears to be associated with diabetic nephropathy and sight-threatening retinopathy in patients with Type I diabetes, and it is associated with diabetic nephropathy in patients with Type II diabetes but is HbA(1c)-dependent.

SOURCE: Lindholm E, Bakhtadze E, Sjogren M, et al. The -374 T/A polymorphism in the gene encoding RAGE is associated with diabetic nephropathy and retinopathy in type 1 diabetic patients. Diabetologia 2006; Sep 13 [Epub ahead of print].		 Table of Contents






Atherosclerosis, C-Reactive Protein and Risk for Open-Angle Glaucoma

Atherosclerosis and serum C-reactive protein (CRP) levels are not important risk factors for open-angle glaucoma (OAG), according to Dutch researchers.

In a prospective, population-based cohort study of 3,842 participants aged 55 years and older and at risk for incident OAG, all participants underwent, at baseline (1990 to 1993) and at follow-up (1997 to 1999), the same ophthalmic examination, including visual field testing and optic disc photography. Baseline atherosclerosis was assessed using echography of the carotid arteries, abdominal X-ray examination and ankle-arm index; baseline serum CRP levels were used in the analyses. Diagnoses of OAG were based on an algorithm using optic disc measurements and visual field loss. Odds ratios of OAG were computed with logistic regression analyses. Risk factors were categorized in tertiles and according to standard deviation.

After a mean follow-up of 6.5 years, incident OAG was diagnosed in 87 of 3,842 participants (2.3 percent) at risk for OAG. Carotid artery plaques, carotid intima-media thickness, aortic calcifications, ankle-arm index and CRP levels were not found to be significant risk factors for OAG. The odds ratio for carotid plaques, given for the highest and lowest tertiles, was 1.43 (95 percent confidence interval [CI], 0.68 to 2.99), for carotid intima-media thickness 0.86 (95 percent CI, 0.47 to 1.57), for aortic calcifications 1.02 (95 percent CI, 0.60 to 1.75), for ankle-arm index 0.69 (95 percent CI, 0.38 to 1.25) and for CRP 1.19 (95 percent CI, 0.68 to 2.07).

SOURCE: de Voogd S, Wolfs RC, Jansonius NM, et al. Atherosclerosis, C-reactive protein, and risk for open-angle glaucoma: The Rotterdam Study. Invest Ophthalmol Vis Sci 2006;47(9):3772-6.		 Table of Contents





BRIEFLY
  • BAYER AND REGENERON TO COLLABORATE ON VEGF TRAP FOR EYE DISEASE TREATMENTS. Bayer HealthCare and Regeneron Pharmaceuticals, Inc. announced a collaboration agreement for the global development and commercialization outside the United States of the VEGF Trap for treating eye disease by local administration. The VEGF Trap-Eye, currently in Phase I and Phase II clinical trials, is a protein that binds to or "traps" vascular endothelial growth factor (VEGF) and blocks its activity. VEGF is thought to play a critical role in certain eye diseases. Under the agreement, Bayer and Regeneron will collaborate on the development of the VEGF Trap-Eye through an integrated global plan that encompasses the neovascular form of age-related macular degeneration (wet AMD), diabetic eye diseases and other eye diseases and disorders. The companies will jointly commercialize the VEGF Trap-Eye outside the United States and will share equally in profits from sales outside the United States. Regeneron has exclusive commercialization rights in all indications and will retain 100 percent of all profits from any such sales. Bayer will make an upfront payment to Regeneron of $75 million; the companies will share initial global development costs of more than $250 million over the next three years, after which all expenses will be shared equally. For more information, go to www.regeneron.com.
  • PROTEIN DISCOVERY MAY BE KEY TO TREATING AMD. A protein that prevents blood vessels from forming in the cornea could be the basis for new age-related macular degeneration (AMD) and cancer treatments, according to a group of international scientists at the University of Kentucky who discovered it. The researchers identified a protein, sVEGFR-1, that at sufficient levels appears to prevent vessel formation in the eye, and is likely the reason why the cornea is without blood vessels. The cornea contains large amounts of the chemical VEGF-A, which promotes blood vessel growth, yet it has been a mystery as to why blood vessels do not form there. The newly discovered protein is likely to be the answer. Produced in the cornea, sVEGFR-1 acts as a "mop" to absorb VEGF-A. The researchers are now concentrating on understanding how the body produces sVEGFR-1; they have already conducted small studies on animals with the goal of developing a synthesized version of the protein that can be administered via eye drops.
  • CLINICAL TRIALS ANNOUNCED FOR AMD AND GLAUCOMA TREATMENT. ScyFIX, a Minnesota-based medical device venture specializing in minimally invasive treatments for eye diseases, has announced upcoming clinical trials for a device that has shown efficacy in treating age-related macular degeneration (AMD) and glaucoma. The company’s flagship device employs microcurrent stimulation (MCS) technology, in which precise, minute amounts of electrical current are applied to specific locations over the closed eyelid. Research has demonstrated that electrical stimulation activates the eye’s endogenous neuroprotective system; it also shows that neurotrophins gradually increase in the retina after treatment, peaking by seven days after treatment. The results suggest that repeated stimulation may offer the possibility for a chronic neuroprotective treatment that is simpler, safer and less invasive than neurotrophic therapy alternatives involving intravitrial injection or gene therapy. The ScyFIX MCS device is approved by regulators in Australia, Canada and Europe, and has been used to treat more than 1,000 patients outside of the United States. Field results indicate safety and efficacy with no observed side effects. The treatment has routinely halted the progression of retinal diseases and in many cases improved vision. Phase I trials are expected to begin by January 1, 2007; Phase II trials will begin if Phase I results are satisfactory and if sufficient funding is received.


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