Treatment of nonexudative (dry) age-related macular degeneration

Methods for culturing retinal pigment epithelial cells: a review of current protocols and future recommendations

The retinal pigment epithelium is an important part of the vertebrate eye, particularly in studying the causes and possible treatment of age-related macular degeneration. The retinal pigment epithelium is difficult to access in vivo due to its location at the back of the eye, making experimentation with age-related macular degeneration treatments problematic. An alternative to in vivo experimentation is cultivating the retinal pigment epithelium in vitro, a practice that has been going on since the 1970s, providing a wide range of retinal pigment epithelial culture protocols, each producing cells and tissue of varying degrees of similarity to natural retinal pigment epithelium. The purpose of this review is to provide researchers with a ready list of retinal pigment epithelial protocols, their effects on cultured tissue, and their specific possible applications. Protocols using human and animal retinal pigment epithelium cells, derived from tissue or cell lines, are discussed, and recommendations for future researchers included.

Haemorheopheresis could block the progression of the dry form of age-related macular degeneration with soft drusen to the neovascular form

PURPOSE

To evaluate the influence of haemorheopheresis on anatomical and functional findings in patients with soft-drusen maculopathy.

METHODS

We investigated 29 eyes (16 patients) and randomized 25 eyes (16 controls) with soft-drusen maculopathy [soft, confluent and reticular drusen, drusenoid retinal pigment epithelium detachment (RPED)]. Each patient received a series of eight haemorheophereses (cascade filtration of 1.5 plasma volume) within 10 weeks. The patients were followed up using Early Treatment Diabetic Retinopathy Study (ETDRS) charts, optical coherence tomography, fluorescein angiography, electroretinography and measurements of pulsed ocular blood flow.

RESULTS

After the procedures, there was a substantial reduction in rheologically active substances [lipoproteins, α2-macroglobulin, immunoglobulin M (IgM), fibrinogen], plasma and blood viscosity. At the 1.5-year follow-up, we noticed soft drusen absorption; reattachment of drusenoid RPED and stabilization or improvement of visual acuity occurred in 72% of patients in comparison to only 39% of patients in the control group. Full-field electroretinograms showed significantly higher scotopic activity of treated patients in comparison with the control group, and mainly insignificant differences in photopic activity between both groups. Despite the significant increase of activity in the paramacular retina in treated patients, the differences in amplitudes of multifocal electroretinography (mfERG) average responses were insignificant between groups.

CONCLUSION

Haemorheopheresis seems to be capable of changing the activity of promoters of the natural course of soft-drusen maculopathy, its development and progression. Visual acuity and electrical activity of the retina can be stabilized or even improved. The therapy has been shown to be effective and safe.

Supplements and age-related eye conditions the beaver dam eye study

OBJECTIVE

To investigate the association of use of vitamin, mineral, and nonvitamin nonmineral supplements with common age-related eye diseases.

DESIGN

Population-based prospective study with incidence data.

PARTICIPANTS

Subjects were participants in the Beaver Dam Eye Study who contributed data in 1988 to 1990 (n = 4926), 1993 to 1995 (n = 3722), 1998 to 2000 (n = 2962), and 2003 to 2005 (n = 2375).

METHODS

Use of all medications and supplements were collected from study participants at each of 4 examinations. Intraocular pressure (IOP) measurement and fundus and lens photography were done at each visit. Visual field data are available only from baseline. Photographs of the lenses, retina, and discs were graded using standard protocols by trained graders.

MAIN OUTCOME MEASURES

Incidence of age-related cataracts, macular degeneration (AMD), and high IOP for one set of analyses and incidence of supplement use for the second set of analyses.

RESULTS

There was little evidence of any significant associations between supplement use and incident ocular outcomes except for a small protective effect for cortical cataracts by vitamins A and D, zinc, and multivitamins and increased odds of late AMD. Late AMD was associated with incident use of vitamins A, C, and E and zinc.

CONCLUSIONS

Age-related macular degeneration seems to precede use of vitamins A, C, and E and zinc. This may reflect advice by family, friends, and health care providers about the benefits of Age-Related Eye Disease Study-like supplements.

Sustained-release ophthalmic drug delivery systems for treatment of macular disorders: present and future applications

Macular disease currently poses the greatest threat to vision in aging populations. Historically, most of this pathology could only be dealt with surgically, and then only after much damage to the macula had already occurred. Current pathophysiological insights into macular diseases have allowed the development of effective new pharmacotherapies. The field of drug delivery systems has advanced over the last several years with emphasis placed on controlled release of drug to specific areas of the eye. Its unique location and tendency toward chronic disease make the macula an important and attractive target for drug delivery systems, especially sustained-release systems. This review evaluates the current literature on the research and development of sustained-release posterior segment drug delivery systems that are primarily intended for macular disease with an emphasis on age-related macular degeneration.Current effective therapies include corticosteroids and anti-vascular endothelial growth factor compounds. Recent successes have been reported using anti-angiogenic drugs for therapy of age-related macular degeneration. This review also includes information on implantable devices (biodegradable and non-biodegradable), the use of injected particles (microspheres and liposomes) and future enhanced drug delivery systems, such as ultrasound drug delivery. The devices reviewed show significant drug release over a period of days or weeks. However, macular disorders are chronic diseases requiring years of treatment. Currently, there is no 'gold standard' for therapy and/or drug delivery. Future studies will focus on improving the efficiency and effectiveness of drug delivery to the posterior chamber. If successful, therapeutic modalities will significantly delay loss of vision and improve the quality of life for patients with chronic macular disorders.

Two genetic pathways for age-related macular degeneration

The discovery of strong associations of the His402 variant of complement factor H (CFH) and the change in the promoter region of HtrA serine peptidase 1 (HTRA1) with age-related macular degeneration (AMD) have altered our conception of the pathophysiology of this disease. The complement system has been placed at the center of a flurry of research interest, and a similar growth in attention to the serine proteases is not far behind. The specific role of these variants in causing AMD is unknown, but they will undoubtedly lead to a deeper understanding of the biological mechanisms and will point to new avenues for pharmacologic management. Furthermore, these variants will enable clinicians and investigators to identify people at high risk for this condition, thereby establishing the preconditions for preventing the disease.

Relationship between age-related macular degeneration-associated variants of complement factor H and LOC387715 with coronary artery disease

OBJECTIVE

To determine whether either of the gene variants associated with age-related macular degeneration is associated with coronary artery disease (CAD).

PATIENTS AND METHODS

This study consisted of 493 patients who underwent clinically indicated coronary angiography between June 1, 1998, and January 1, 1999. The Y402H variant of the complement factor H (CFH) gene and the A69S variant of the LOC387715 gene locus were examined by restriction fragment length polymorphism. Multiple logistic regression models were used to assess the association of CFH and LOC gene variants with CAD. Covariates with well-established associations with CAD were also evaluated.

RESULTS

Seventy patients (14%) were homozygous for the histidine variant (HH) of CFH, 237 (48%) were heterozygous for the histidine variant (HY), and 186 (38%) were homozygous for the tyrosine variant (YY). Three hundred eight patients (62%) were homozygous for the alanine allele of LOC387715, 170 (34%) were heterozygous for Ala and Ser alleles, and 15 (3%) were homozygous for the serine variant. The overall association of the CFH genotype with CAD was not statistically significant (P=.08). However, some evidence (P=-.046) suggested that CAD was increased for the HH genotype compared to the homozygous wild-type YY genotype (odds ratio, 1.95; 95% confidence interval, 1.01-3.76). Male sex, hypertension, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and age were other variables that demonstrated significant associations with CAD. The overall effect of the LOC genotype was not statistically significant (P=-.06). Heterozygosity for the serine variant was (P=-.02) associated with the absence of CAD vs the AS genotype (odds ratio, 0.59; confidence interval, 0.38-0.91; P=-.02).

CONCLUSION

The CFH genotype may have an independent association with CAD, although our evidence did not show statistical significance. Controlling for known risk factors, the age-related macular degeneration-associated HH variant appears to be associated with CAD. The LOC387715 gene may also play a role in CAD.