Triamcinolone acetonide modulates permeability and intercellular adhesion molecule-1 (ICAM-1) expression of the ECV304 cell line: implications for macular degeneration

Ranibizumab in neovascular age-related macular degeneration

Neovascular age-related macular degeneration (AMD) is a visually devastating condition resulting from choroidal neovascularization and secondary photoreceptor loss. Ranibizumab and bevacizumab are medications that target vascular endothelial growth factor (VEGF). While other therapies have demonstrated some ability to reduce the risk of losing vision from neovascular AMD, most patients continue to lose some degree of central visual acuity. There is growing evidence that intravitreal administration of ranibizumab and bevacizumab is effective in significantly improving the visual acuity in patients with neovascular age-related macular degeneration.

Intravitreal triamcinolone acetonide for treatment of serous macular detachment in central retinal vein occlusion

PURPOSE

To evaluate the effect of intravitreal triamcinolone acetonide (IVTA) treatment on serous macular detachment in patients with central retinal vein occlusion (CRVO).

METHODS

Ten eyes of 10 patients with CRVO (6 men and 4 women; age range, 54-78 years) made up the study population. The eligibility criteria for this study included clinically and angiographically detectable cystoid macular edema (CME) in which the presence of serous macular detachment was documented by optical coherence tomography (OCT). After IVTA (4 mg/0.1 mL) injection, visual and anatomical responses were observed.

RESULTS

In all eyes, after IVTA injection, CME and serous macular detachment regressed. At 3 months and 6 months, CME and serous macular detachment had recurred in 4 (40%) and 5 eyes (50%), respectively. Patients with recurrence were retreated. No eyes lost vision at 1 month, and all eyes had improvement. At 3 months, no eyes had lost vision from baseline, and 7 eyes (70%) had improvement. At 6 months, again no eyes had lost vision from baseline, and 6 eyes (60%) maintained improved visual acuity.

CONCLUSIONS

Our study shows that IVTA is effective treatment for serous macular detachment in patients with CRVO.

Triamcinolone acetonide in ocular therapeutics

Triamcinolone acetonide has been effectively used in ocular therapeutics for over 50 years. Its use has increased dramatically in recent years for periocular and intraocular treatment of retinal vasculature disease and uveitis. This comprehensive review discusses the pharmacokinetics of triamcinolone acetonide and summarizes its uses in a number of diseases, both intraocular and extraocular. It discusses side effects and their management. Finally, it discusses the controversy over its use.

Current Treatment of Age-Related Macular Degeneration

PURPOSE

To review proved and experimental treatments for exudative and nonexudative complications of age-related macular degeneration (AMD), to consider the impact of current therapy on the structure of future clinical trials, and to consider the role of improved diagnostic imaging techniques on the effectiveness of current therapy as well as the structure of future clinical trials in AMD patients.

RESULTS

Defining the cell biology of choroidal new vessel (CNV) formation and geographic atrophy will lead to identification of different biochemical pathways that are the target of AMD treatment. Many treatments and treatment combinations are under study for AMD, but all work through a finite number of pathways. Currently, the most effective proved therapy for AMD-associated CNVs is administered by repeated intravitreal injection of agents that inhibit vascular endothelial growth factor, e.g., ranibizumab. Improved drug delivery will enhance patient satisfaction and possibly will enhance the effectiveness and reduce the risk of current pharmacotherapy for AMD-associated CNVs. Combination therapy (e.g., verteporfin-photodynamic therapy + ranibizumab) appears to reduce the risk and enhance the effectiveness of CNV treatment compared with monotherapy with currently available agents. Improved noninvasive diagnostic imaging may lead to better visual outcomes with existing therapeutic modalities. Improved imaging also may alter favorably the design of future clinical trials for AMD-associated CNVs and thus reduce cost and increase the diversity of sight-saving treatments.

CONCLUSIONS

Delineation of the biochemical basis for CNV formation has led to development of pathway-based pharmacotherapy for AMD patients. Areas of investigation that will advance the field further include combination therapy, improved drug delivery, and improved noninvasive, high-resolution diagnostic imaging. The logistics of future clinical trials will be complicated by the need for an active treatment control group, more stringent definition of successful treatment, and the increased numbers of patients required for combination therapy studies.

Current treatment approaches in diabetic macular edema

PURPOSE

To review current treatment approaches in diabetic macular edema (DME).

METHODS

The underlying pathopathology, classifications and diagnostic examination techniques including fluorescein angiography, optical coherence tomography and stereoscopic biomicroscopy. Treatment modalities with focal or grid argon laser photocoagulation, pars plana vitrectomy with and without peeling of the inner limiting membrane (ILM), as well as intravitreal injections using triamcinolone acetonide or novel vascular endothelial growth factor (VEGF) inhibitors are described.

RESULTS

DME results from a series of biochemical and cellular changes, causing progressive leakage and exudation. Focal and grid photocoagulation remains the standard care for diabetic maculopathy. However, the availability of new agents raises the possibility of improvements if significant benefits can be validated in randomized clinical trials. Posterior vitreous attachments play a critical role through several mechanical or physiological mechanisms. Vitrectomy without ILM removal seems to be effective in reducing the retinal thickness and improving visual acuity.

CONCLUSION

A proper evaluation of the vitreous and retina is fundamental to select the most appropriate treatment approach in DME. While small microaneurysms with focal DME may be treated by conventional focal photocoagulation, diffuse DME which do not respond to grid photocoagulation may benefit from intravitreal injections using triamcinolone acetonide or novel VEGF inhibitors. Eyes with DME and additional vitreous traction may benefit from pars plana vitrectomy without ILM peeling. A combination of laser, pharmacological and surgical treatment modalities may be necessary to maintain central vision in eyes with DME.

Verteporfin photodynamic therapy and anti-angiogenic drugs: potential for combination therapy in exudative age-related macular degeneration

OBJECTIVE

To discuss the rationale for combining anti-angiogenic treatment with verteporfin (Visudyne) photodynamic therapy in the management of choroidal neovascularization (CNV) due to age-related macular degeneration (AMD) and evaluate available evidence for the therapeutic benefits of such approaches.

SCOPE

The Medline and EMBASE databases were searched in October 2006 to retrieve relevant articles. Additional articles were obtained from the reference lists of retrieved articles, as well as from recent scientific meetings and company websites.

FINDINGS

Treatments for CNV due to AMD can be directed at either the vascular component of CNV (the new vessels that proliferate and leak blood and fluid) or the angiogenic component that leads to the development of the condition. Verteporfin targets the vascular component, whereas anti-angiogenic agents (such as pegaptanib and ranibizumab) target key mediators of the angiogenic cascade. The different mechanisms of action of these approaches offer the potential for additive or synergistic effects with combination therapy. In addition, anti-angiogenic agents might counteract upregulation of angiogenic factors (including VEGF) that occur after verteporfin photodynamic therapy. Results from preclinical and clinical studies of the combination of ranibizumab or pegaptanib with verteporfin warrant continued investigation.

CONCLUSIONS

The use of anti-angiogenic agents in combination with verteporfin may have the potential to improve visual outcomes and reduce the number of treatments in eyes with CNV due to AMD, and requires further evaluation in randomized, controlled clinical trials.

A review of drug options in age-related macular degeneration therapy and potential new agents

Age-related macular degeneration (AMD) is the leading cause of legal blindness in people > 50 years of age in the developed world. AMD is both a debilitating and costly disease for the individual and the community. Greater understanding of the mechanisms and pathways involved in causing the visual loss in AMD has resulted in the advent of several newer and more effective treatment options, making it an exciting time in the management of AMD. This paper will examine the principles behind the existing drug therapies available, as well as those being developed in the management or prophylaxis of AMD and its vision-threatening complications.

COMBINED PHOTODYNAMIC THERAPY WITH VERTEPORFIN AND INTRAVITREAL BEVACIZUMAB FOR CHOROIDAL NEOVASCULARIZATION IN AGE-RELATED MACULAR DEGENERATION

PURPOSE

To examine the 7-month results for patients treated with combined photodynamic therapy (PDT) with verteporfin and intravitreal bevacizumab for choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD).

METHODS

This is a retrospective series of 24 eyes with juxtafoveal or subfoveal CNV secondary to AMD. Patients were treated with PDT with verteporfin and 1.25 mg of intravitreal bevacizumab. All patients were naive to treatment and had either treatment within a 14-day interval. Main outcome measures were visual acuity stabilization (defined as no change or a gain in visual acuity) and retreatment rate.

RESULTS

At the 7-month follow-up, 20 (83%) of 24 patients had stabilization of visual acuity. Sixteen eyes (67%) had improvement in visual acuity. Mean improvement in visual acuity (n = 24) was 2.04 Snellen lines. Fifteen eyes (63%) required only a single combined treatment for CNV resolution. There were no complications, including endophthalmitis, uveitis, and ocular hypertension.

CONCLUSION

The results of this study suggest that combined treatment of PDT with verteporfin and intravitreal bevacizumab may be useful in treating neovascular AMD by reducing retreatment rates and improving visual acuity. Further investigation with large, controlled trials is warranted to outline the appropriate treatment paradigm for combination therapy.

Atrial natriuretic peptide inhibits osmotical glial cell swelling in the ischemic rat retina: Dependence on glutamatergic-purinergic signaling

Atrial natriuretic peptide (ANP) is a regulator of the water and electrolyte content in the brain which also mediates cell volume homeostasis. Here, we determined whether the expression of ANP in the retina of the rat undergoes changes during ischemia-reperfusion, and whether ANP affects the osmotic swelling of Müller glial cells in postischemic retinas under hypotonic conditions. Transient retinal ischemia was induced by elevation of the intraocular pressure above systolic blood pressure for 1h. At 1 and 3 days after reperfusion, there was an increased content of ANP protein in the retina, as determined by Western blotting. The increase of the retinal ANP content was markedly reduced when triamcinolone acetonide (10 mM in 2 microl vehicle) was intravitreally injected before ischemia. ANP inhibited the osmotic swelling of Müller cell somata in retinal slices. The effect of ANP was mediated by activation of NP receptors expressed by retinal neurons which evoked a release of glutamate. The stimulation of metabotropic glutamate receptors expressed by Müller cells evoked an autocrine purinergic signaling mechanism that resulted in the opening of K(+) and Cl(-) channels; the ion efflux counteracted the osmotic swelling of Müller cells. It is concluded that the expression of ANP is transiently upregulated in the postischemic retina of the rat. The increased expression of ANP may represent a part of the retinal response to transient ischemia and may inhibit cytotoxic glial cell swelling.

Promising new treatments for neovascular age-related macular degeneration

Angiogenesis, the growth of new blood vessels from existing blood vessels, is responsible for vision loss in a variety of ophthalmic diseases. In neovascular age-related macular degeneration (AMD), the leading cause for legal blindness in many industrialised countries, abnormal blood vessels grow in the macula and cause blindness. There are a number of factors important in the angiogenic cascade but VEGF-A has been implicated in recent years as the major factor responsible for neovascular and exudative diseases of the eye. Numerous antiangiogenic drugs are in development but anti-VEGF drugs have shown great promise in treating neovascular AMD and other ocular diseases, and many of these drugs have been adopted from oncology where antiangiogenic therapy is gaining wide acceptance. For the first time in neovascular AMD, anti-VEGF drugs have brought the hope of vision improvement to a significant proportion of patients. This review provides an overview on angiogenic mechanisms, potential antiangiogenic treatment strategies and different antiangiogenic drugs with special focus on neovascular AMD.

Combined photodynamic therapy and intravitreal triamcinolone acetonide for the treatment of myopic subfoveal choroidal neovascularization

PURPOSE

To evaluate visual acuity changes and safety of combined treatment with photodynamic therapy (PDT) and intravitreal triamcinolone acetonide (IVTA) in myopic eyes with choroidal neovascularization (CNV).

DESIGN

Prospective interventional case series.

METHODS

Twelve eyes of 12 patients with subfoveal myopic CNV were treated with PDT followed by IVTA within a week. Changes in visual acuity and possible complications related to the combined therapy were assessed in periodic visits.

RESULTS

After combined therapy, a significant increase in mean visual acuity was observed at one, three, and six months. A significant increase of mean intraocular pressure was observed after seven days, one month, and three months. Ten patients (83%) required topical antiglaucomatous therapy during follow-up.

CONCLUSIONS

The combination of PDT and IVTA may increase the possibility of improving or stabilizing visual acuity in patients with subfoveal myopic CNV, but further studies are needed to asses the effects of this treatment.

Intravitreal triamcinolone acetonide: a change in a paradigm

BACKGROUND

Based on experimental studies and clinical observations by Robert Machemer, Gholam Peyman and others, the vitreous cavity has increasingly been used as a reservoir of drugs for the direct treatment of intraocular diseases.

METHODS AND RESULTS

The most widely injected drug so far has been triamcinolone acetonide for various intraocular neovascular and edematous diseases. Comparing the various diseases with respect to effect and side effects of the treatment, the best response in terms of gain in visual acuity has been achieved for intraretinal edematous diseases such as diffuse diabetic macular edema, branch retinal vein occlusion, central retinal vein occlusion, and pseudophakic cystoid macular edema. In eyes with various types of noninfectious uveitis including acute or chronic sympathetic ophthalmia and Adamantiadis-Behçet's disease, visual acuity increased and the degree of intraocular inflammation decreased. Some studies have suggested that intra- vitreal triamcinolone may be useful as an angiostatic agent in eyes with iris neovascularization and proliferative ischemic retinopathies. Intravitreal triamcinolone may possibly be helpful as adjunct therapy for exudative age-related macular degeneration, particularly in combination with photodynamic therapy. In eyes with chronic, therapy-resistant ocular hypotony, intravitreal triamcinolone can induce an increase in intraocular pressure and may stabilize the eye. The complications of intravitreal triamcinolone therapy include secondary ocular hypertension in about 40% of the eyes injected; medically uncontrollable high intraocular pressure leading to antiglaucomatous surgery in about 1-2% of the eyes; posterior subcapsular cataract and nuclear cataract leading to cataract surgery in about 15-20% in elderly patients within 1 year after injection; postoperative infectious endophthalmitis with a rate of about 1:1,000; noninfectious endophthalmitis, perhaps due to a reaction to the solvent agent, and pseudoendophthalmitis with triamcinolone acetonide crystals appearing in the anterior chamber. Intravitreal triamcinolone injection can be combined with other types of intraocular surgery including cataract surgery, particularly in eyes with iris neovascularization. Cataract surgery performed some months after the injection does not show a markedly elevated complication rate. The injection may be repeated, if vision redecreases. In nonvitrectomized eyes, the duration of the effect and side effects of a single intravitreal injection of triamcinolone is about 6-9 months for a dosage of about 20 mg, and about 2-4 months for a dosage of 4 mg. It has remained unclear so far, whether and how to remove the solvent agent. In the future, intravitreal triamcinolone may be combined with other antiangiogenic drugs for the treatment of exudative age-related macular degeneration or with neuroprotective drugs for treatment of diabetic retinopathy.

CONCLUSIONS

Despite an exponentially increasing number of mostly case-series studies, the intravitreal injection of triamcinolone may still be considered an experimental procedure until randomized studies have been presented.

Current and future pharmacological intervention for diabetic retinopathy

Diabetic retinopathy (DR) is a potentially visually devastating complication of chronic hyperglycaemia. Prospective, randomised clinical trials have delineated the standard prevention protocols, including intensive glycaemic, blood pressure, and lipid control, and laser photocoagulation treatment for neovascularisation and clinically significant macular oedema. However, despite these interventions, vision loss from DR still occurs at an alarming rate. Researchers have directed their efforts towards better understanding the specific biological and chemical changes occurring in DR to develop more targeted pharmacological prevention and treatment strategies. This review of diabetic retinopathy will primarily detail the therapies in development at present, including aldose reductase inhibitors, advanced glycosylation end product inhibitors, antioxidants, supplemental oxygen, growth factor modulators including vascular endothelial growth factor inhibitors and protein kinase C inhibitors, extracellular matrix modifiers including corticosteroids, and vitreous modulators. The experimental therapies alter several different pathways that lead to DR. Future research will further delineate these pathways, and therapy is likely to involve arresting several different promoters of DR.

Remodeling of the vascular channels in retinal angiomatous proliferations treated with intravitreal triamcinolone acetonide and photodynamic therapy

BACKGROUND

The objective was to describe the remodeling of the vascular channels in stage II retinal angiomatous proliferation (RAP) treated by intravitreal injections of triamcinolone acetonide (TA) and subsequent photodynamic therapy (PDT).

METHODS

Stage II RAP secondary to age-related macular degeneration was documented by dynamic digital fluorescein and indocyanine green angiography in 3 consecutive patients (3 eyes). All eyes were treated with intravitreal injection of TA (4 mg, 0.1 ml) followed by PDT 5-10 days later.

RESULTS

Indocyanine green angiography (ICGA) revealed a complete remodeling of the vascular structure of the three RAPs after treatment. The feeding retinal artery, which shunted a major part of the blood flow from the original arteriole toward the intraretinal neovascular complex before treatment, regained a normal appearance after treatment. With RAP closure, the blood flow was again directed through the original retinal arteriole, and the connection to the RAP was no longer visible.

CONCLUSIONS

Stage II RAPs are difficult lesions to treat. A real remodeling of the vascular lesion is achieved with the combined use of intravitreal TA and PDT. This finding corroborates the need for randomized clinical trials currently under way to evaluate this combination treatment in wet, age-related macular degeneration.

Verteporfin and intravitreal triamcinolone acetonide combination therapy for occult choroidal neovascularization in age-related macular degeneration

PURPOSE

To evaluate the efficacy and safety of photodynamic therapy (PDT) with verteporfin combined with intravitreal triamcinolone (IVTA) in occult choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD).

DESIGN

Single center, nonrandomized interventional case series.

METHODS

A prospective, noncomparative, interventional case series of 41 eyes of 41 patients with a two-year follow-up period. Verteporfin PDT was performed using the recommended standard procedure for approved forms of AMD. A solution containing 25 mg of crystalline triamcinolone acetonide was injected intravitreally 16 hours post PDT. The procedure was repeated after three months in case of persistent CNV leakage.

RESULTS

The mean number of treatments needed was 1.8. Thirty-four eyes (82.9%) required one retreatment at three months. No additional retreatments were necessary. Visual acuity improved gradually in most of the patients with mean values of 20/133 and 20/115 at baseline and three months; 20/101 and 20/84 at six and twelve months; and 20/83 and 20/81 at eighteen and twenty-four months. Eleven of 41 treated study eyes (26.8%) underwent cataract surgery between six and fifteen months after the first treatment. Nine patients required local or systemic glaucoma therapy because of a transient steroid induced intraocular pressure increase.

CONCLUSIONS

Verteporfin PDT combined with intravitreal triamcinolone may improve the outcome of standard verteporfin PDT in the treatment of occult CNV secondary to AMD. An improvement in visual acuity was observed in most of the treated patients and was maintained during a two-year follow-up period. Retreatment numbers were lower than expected from monotherapy trials.

Intravitreal triamcinolone acetonide for treatment of intraocular oedematous and neovascular diseases

Intravitreal triamcinolone acetonide (IVTA) has increasingly been applied as treatment for various intraocular neovascular and oedematous diseases. Comparing the various diseases with respect to effect and side-effects of the treatment, the best response in terms of gain in visual acuity (VA) has been achieved for intraretinal oedematous diseases such as diffuse diabetic macular oedema, branch retinal vein occlusion, central retinal vein occlusion and pseudophakic cystoid macular oedema. In eyes with various types of non-infectious uveitis, including acute or chronic sympathetic ophthalmia and Adamantiadis-Behcet's disease, VA increased and the degree of intraocular inflammation decreased. Some studies have suggested that intravitreal triamcinolone may be useful as angiostatic therapy in eyes with iris neovascularization and proliferative ischaemic retinopathies. Intravitreal triamcinolone may possibly be helpful as adjunct therapy for exudative age-related macular degeneration (AMD), particularly in combination with photodynamic therapy. In eyes with chronic, therapy-resistant ocular hypotony, intravitreal triamcinolone can induce an increase in intraocular pressure (IOP) and may stabilize the eye. The complications of intravitreal triamcinolone therapy include: secondary ocular hypertension in about 40% of the eyes injected; medically uncontrollable high IOP leading to antiglaucomatous surgery in about 1-2% of the eyes; posterior subcapsular cataract and nuclear cataract leading to cataract surgery in about 15-20% of elderly patients within 1 year of injection; postoperative infectious endophthalmitis occurring at a rate of about one per 1000; non-infectious endophthalmitis, perhaps due to a reaction to the solvent agent, and pseudo-endophthalmitis with triamcinolone acetonide crystals appearing in the anterior chamber. Intravitreal triamcinolone injection can be combined with other intraocular surgeries, including cataract surgery, particularly in eyes with iris neovascularization. Cataract surgery performed some months after the injection does not show a markedly elevated complication rate. The injection may be repeated if the resultant benefits decrease after the initial IVTA injection. In non-vitrectomized eyes, the duration of the effect and side-effects of a single intravitreal injection of triamcinolone is about 6-9 months for a dosage of about 20 mg, and about 2-4 months for a dosage of 4 mg. So far, it has remained unclear whether the solvent agent should be removed, and if so, how.

'What controls aqueous humour outflow resistance?'

The bulk of aqueous humour outflow resistance is generated in or near the inner wall endothelium of Schlemm's canal in normal eyes, and probably also in glaucomatous eyes. Fluid flow through this region is controlled by the location of the giant vacuoles and pores found in cells of the endothelium of Schlemm's canal, but the flow resistance itself is more likely generated either in the extracellular matrix of the juxtacanalicular connective tissue or the basement membrane of Schlemm's canal. Future studies utilizing in vitro perfusion studies of inner wall endothelial cells may give insights into the process by which vacuoles and pores form in this unique endothelium and why inner wall pore density is greatly reduced in glaucoma.

Rationale for combination therapies for choroidal neovascularization

PURPOSE

To provide a conceptual framework for the development and use of combination therapies for choroidal neovascularization secondary to age-related macular degeneration.

DESIGN

Literature review, integration of data, and creation of hypothesis.

METHODS

An assessment of angiogenesis, cancer therapy, and inflammation was performed as they may pertain to choroidal neovascularization. A conceptual framework was created in which therapies for choroidal neovascularization could be evaluated alone or in combination.

RESULTS

Angiogenesis occurs because cells produce angiogenic stimuli to encourage blood vessels to develop. This growth of vessels involves an orchestrated interaction among many mediators offering opportunity to modulate or inhibit the entire process. A two-component model for choroidal neovascularization is proposed. The vascular component of choroidal neovascularization is comprised of vascular endothelial cells, endothelial cell precursors, and pericytes. The extravascular component, which by histopathology appears to be both the source of angiogenic stimuli and often the largest component volumetrically, is comprised of inflammatory, glial and retinal pigment epithelial cells, and fibroblasts. Tissue damage can be caused by either component. Each component can be targeted through as variety of monotherapies. Combination therapies offer the possibility of attacking one component in more than one way or by attacking both components simultaneously.

CONCLUSIONS

The two-component model of choroidal neovascularization can be used to evaluate the mechanism of action and possible interactions of these agents in a conceptual framework. Extension of these ideas can help guide development of new treatment agents and approaches.

OCCULT WITH NO CLASSIC CHOROIDAL NEOVASCULARIZATION SECONDARY TO AGE-RELATED MACULAR DEGENERATION TREATED BY INTRAVITREAL TRIAMCINOLONE AND PHOTODYNAMIC THERAPY WITH VERTEPORFIN

PURPOSE

To examine combined treatment with intravitreal triamcinolone acetonide (IVT) and photodynamic therapy (PDT) for occult with no classic choroidal neovascularization (CNV) secondary to age-related macular degeneration.

METHODS

In this prospective, interventional case series, 11 eyes of 10 consecutive patients with occult with no classic CNV underwent a single injection (25 mg) of IVT followed 1 month later by PDT. Best-corrected visual acuity was measured by Early Treatment Diabetic Retinopathy Study (ETDRS) protocol refraction.

RESULTS

Median best-corrected visual acuity was 20/160, 20/80, 20/80, 20/50, and 20/80 at baseline and 1, 3, 6, and 12 months, respectively. Best-corrected visual acuity at baseline was statistically different (P < 0.05) than best-corrected visual acuity at 1, 3, and 6 months. Of 11 eyes, 5 (45.5%), 7 (63.6%), 7 (63.6%), and 4 (36.3%) had improved best-corrected visual acuity of at least 3 ETDRS lines at 1, 3, 6, and 12 months, respectively, while 6 (54.5%), 9 (81.8%), 10 (91%), and 8 (73%) had improved best-corrected visual acuity of at least 2 ETDRS lines at 1, 3, 6, and 12 months, respectively. Two eyes (18%) lost >3 lines at 12 months. One eye had intraocular hypertension at 3 months and was treated with a combination of topical antiglaucomatous drugs. One eye developed a dense cataract at the last follow-up visit. No endophthalmitis, retinal detachment, or vitreous hemorrhage developed. Fluorescein leakage and retinal thickness reduced significantly after treatment.

CONCLUSIONS

Improvement of best-corrected visual acuity and lack of fluorescein leakage suggest combination treatment with IVT and PDT for occult with no classic CNV merits further investigation.

Verteporfin Therapy Combined with Intravitreal Triamcinolone in All Types of Choroidal Neovascularization due to Age-Related Macular Degeneration

OBJECTIVE

To evaluate the efficacy and safety of photodynamic therapy with verteporfin combined with intravitreal triamcinolone in choroidal neovascularization secondary to age-related macular degeneration (AMD).

DESIGN

Prospective, noncomparative, interventional case series.

PARTICIPANTS

One hundred eighty-four patients undergoing treatment for neovascular AMD at one retinal referral center.

METHODS

One hundred eighty-four eyes of 184 consecutive patients (63.6% female, 36.4% male) with a mean age of 76.5 years and a follow-up of a median of 38.8 weeks (range, 12-103) were included in a case series. One hundred forty-eight (80.4%) patients had subfoveal choroidal neovascularization, 19 patients (10.3%) had juxtafoveal choroidal neovascularization, and 17 patients (9.2%) had extrafoveal choroidal neovascularization. Verteporfin photodynamic therapy was performed using the recommended standard procedure. A solution containing 25 mg of triamcinolone was injected intravitreally 16 hours after photodynamic therapy in 184 patients. The combined therapy procedure was repeated at the 3-month follow-up visits whenever persistent choroidal neovascularization leakage was documented angiographically.

MAIN OUTCOME MEASURES

Mean change in best-refracted visual acuity (VA) between baseline and the last visit, and number of treatments necessary to achieve absence of leakage.

RESULTS

Visual acuity improved in the majority of patients (baseline VA, mean 20/125) by a mean increase of 1.22 Snellen lines and 1.43 lines using laser interferometry (P<0.01). The mean number of required treatments was 1.21. Twenty-three eyes (12.5%) required 2 treatments, 6 eyes (3.26%) required 3 treatments, and 1 eye (0.5%) required 4 treatments. The combination treatment including laser and intravitreal steroid administration was well tolerated. Forty-six patients (25%) required glaucoma therapy due to a transient steroid-induced intraocular pressure (IOP) increase. Twelve patients (6.5%) were on topical medication for preexisting glaucoma. Two patients (1%) whose IOP increase could not be controlled with topical therapy required surgery.

CONCLUSIONS

Verteporfin photodynamic therapy combined with intravitreal triamcinolone may improve the outcome of standard verteporfin photodynamic therapy in the treatment of choroidal neovascularization secondary to AMD. A significant improvement in VA was observed in a majority of treated patients and was maintained during the maximum follow-up. In addition, retreatment rates were lower than anticipated.

Complications of intravitreal steroid injections

BACKGROUND

Intravitreal corticosteroid injections are a new therapeutic procedure used to treat various retinal edematous and neovascular conditions. They have been used in the treatment of diabetic macular edema, exudative macular degeneration, pseudophakic cystoid macular edema, macular edema associated with retinal vein occlusion, and chronic uveitis as well as other conditions. Because the use of this therapeutic technique is becoming increasingly more common, adverse effects are now being seen. The most common adverse effects associated with intravitreal steroid injection are elevation of intraocular pressure and progression of cataract. Endophthalmitis, pseudoendophthalmitis, and retinal detachment have also been reported.

CASE REPORTS

This report describes 2 patients who were followed up at the VA Connecticut Healthcare System Newington Campus Optometry Clinic for steroid-induced elevation of intraocular pressure after intravitreal corticosteroid injection. One patient exhibited elevation of intraocular pressure after his first intravitreal steroid injection for treatment of clinically significant macular edema secondary to diabetes. The second patient did not exhibit a steroid response to the first intravitreal steroid injection utilized as treatment for choroidal neovascularization from age-related macular degeneration. However, he did show a rise in intraocular pressure after a second intravitreal corticosteroid injection. Intraocular pressures, treatment, and frequency of follow-up in both patients pre- and postinjection are discussed.

CONCLUSION

Elevation of intraocular pressure after intravitreal steroid injection can commonly be controlled with topical glaucoma medications. Cataract progression is common in patients after intravitreal injection of corticosteroid; however, findings show these patients are at no additional risk for cataract surgery complications. Therefore, these do not appear to be major contraindications. However, because 30% to 50% of patients experience intraocular pressure rise up to a few months postinjection, and patients are at higher risk for complications such as endophthalmitis, optometrists should be aware of appropriate management after this increasingly utilized therapeutic procedure.

Effect of Posterior Juxtascleral Triamcinolone Acetonide on Choroidal Neovascular Growth after Photodynamic Therapy with Verteporfin

OBJECTIVE

To assess if posterior juxtascleral application of 40 mg triamcinolone acetonide (TA), given at the same time as initial photodynamic therapy (PDT) for predominantly classic choroidal neovascularization (CNV) related to age-related macular degeneration affects lesion growth at 3 and 6 months.

DESIGN

Comparative (nonrandomized) interventional study.

PARTICIPANTS

The study group consists of 38 eyes of 38 patients. The control group consists of 73 eyes of 73 patients.

METHODS

Comparison of 2 consecutive case series collected at different times. The study group had a posterior juxtascleral TA with their initial PDT treatment. The controls were treated with PDT alone. All patients were reviewed at 1, 3, and 6 months.

MAIN OUTCOME MEASURES

Change in total lesion size; secondary outcomes: area of leak, best-corrected visual acuity, number of treatments, and intraocular pressure.

RESULTS

There was significantly less growth of total lesion at 3 months (mean difference = 2.47 mm2; 95% confidence interval (CI): +1.22 to +3.72 mm2; P = 0.0002) and 6 months (mean difference = 2.88 mm2; 95% CI: +0.61 to +5.15 mm2; P = 0.0134) in patients given TA with PDT compared with PDT alone. There was also a significantly smaller residual area of leak at 3 months in the study group (mean difference = 1.07 mm2; 95% CI: +0.16 to +1.97 mm2; P = 0.02). At 6 months, the residual area of leak between the 2 groups became comparable (mean difference = 0.13 mm2; 95% CI = -1.59 to +1.33 mm2; P = 0.86). Mean number of letters lost on the logarithm of the minimum angle of resolution chart at 6 months was 9.1 letters (standard error of the mean [SEM] = 2.21) in the study group compared with 12.4 letters (SEM = 1.91) in the control group (P = 0.30). At 6 months, 10 of 36 eyes (27.8%) in the study group showed > or =15 letters loss, compared with 29 of 73 eyes (39.7%) in the control group. Intraocular pressure was raised in 4 of 38 eyes (10.5%). Fewer retreatments were required in the TA with PDT group (2.03 compared with 2.47 [P = 0.006]).

CONCLUSIONS

Posterior juxtascleral placement of TA with PDT at baseline significantly reduces CNV growth at 3 and 6 months. Fewer retreatments were required. Visual outcome may be improved, although we did not show a statistically significant improvement with this sample size. A larger, randomized trial with longer follow-up is justified.

RESOLUTION OF SEROUS MACULAR DETACHMENT AFTER INTRAVITREAL TRIAMCINOLONE ACETONIDE TREATMENT OF PATIENTS WITH BRANCH RETINAL VEIN OCCLUSION

PURPOSE

To evaluate the effect of intravitreal triamcinolone acetonide on serous macular detachment in patients with branch retinal vein occlusion (BRVO).

METHODS

Eight eyes of 8 patients with BRVO (6 men and 2 women; age range, 52-76 years) made up the study population. The eligibility criteria for this study included clinically and angiographically detectable cystoid macular edema (CME) in which the presence of serous macular detachment was documented by optical coherence tomography (OCT). After intravitreal injection of 0.1 mL (4 mg) of triamcinolone acetonide, the visual and anatomical responses were observed.

RESULTS

In all eyes, after injection of triamcinolone acetonide, CME and serous macular detachment regressed. At 3 and 6 months, CME and serous macular detachment had recurred in 1 eye (12.5%) and 2 eyes (25%), respectively. Patients with recurrence were retreated. No eyes lost vision at 1 month, and all eyes showed improvement. At 3 months, no eyes had lost vision from baseline, and 7 eyes (87.5%) showed improvement. At 6 months, again no eyes had lost vision from baseline, and 7 eyes (87.5%) maintained improved visual acuity.

CONCLUSIONS

The preliminary results of our study showed prompt resolution of serous macular detachment with corresponding improved visual acuity in patients with CME secondary to BRVO. Further study with longer follow-up and a larger series is warranted to assess the long-term efficacy and safety.

INTRAVITREAL TRIAMCINOLONE ACETONIDE FOR DIABETIC MACULAR EDEMA

PURPOSE

Intravitreal injection of triamcinolone acetonide has been advocated to treat exudative diabetic macular edema. The purpose of the study was to evaluate the clinical outcome of an intravitreal injection of triamcinolone acetonide as treatment for diffuse diabetic macular edema.

METHODS

This study was a retrospective, interventional, clinical case series examining 210 eyes of 174 patients who received an intravitreal injection of 1 or 4 mg of triamcinolone acetonide for treatment of diffuse diabetic macular edema. Inclusion criteria were clinically significant macular edema, visual acuity loss, and leakage shown by fluorescein angiography. Main outcome measures were visual acuity and intraocular pressure. Mean follow-up time +/- SD was 6.6 +/- 3.1 months.

RESULTS

In the study group, visual acuity improved significantly (P < 0.001) from a median of 20/200 (mean logMAR, 0.92) at baseline to 20/80 (mean logMAR, 0.82) at 6 months. Mean intraocular pressure +/- SD increased from 15.4 +/- 3.4 mmHg (median, 16 mmHg; range, 6-26 mmHg) to a maximal value of 20.4 +/- 6.2 mmHg (median, 19 mmHg; range, 12-51 mmHg) during the follow-up period. Complications included culture-negative sterile endophthalmitis in six cases and cataract extraction in five eyes.

CONCLUSIONS

Intravitreal injection of 1 to 4 mg of triamcinolone acetonide may benefit patients by improving visual acuity in eyes with clinically significant diabetic macular edema. This study did not provide significant evidence to justify its routine use in clinical practice for all patients with diabetic macular edema. A randomized clinical trial on this issue would provide more conclusive evidence and help identify those patients most likely to benefit from intravitreal triamcinolone acetonide.

The Glucocorticoid Triamcinolone Acetonide Inhibits Osmotic Swelling of Retinal Glial Cells via Stimulation of Endogenous Adenosine Signaling

The glucocorticoid triamcinolone acetonide is clinically used for the treatment of macular edema. However, the edema-resolving mechanisms of triamcinolone are incompletely understood. Since cell swelling is a central cause of cytotoxic edema in the brain and retina, we determined the effects of triamcinolone acetonide on the swelling of retinal ganglion and Müller glial cells in acutely isolated retinas from rats and guinea pigs in situ. Triamcinolone acetonide (100 microM) had no effect on the swelling of ganglion cells that was evoked in isolated whole mounts of the guinea pig retina by acute application of glutamate (1 mM) or high K+ (50 mM). However, triamcinolone reversed the osmotic swelling of Müller glial cells in retinas of the rat that was observed under various experimental conditions: in retinas isolated at 3 days after transient retinal ischemia, in retinas of eyes with lipopolysaccharide-induced ocular inflammation, and in control retinas in the presence of Ba2+ (1 mM), H2O2 (200 microM), arachidonic acid (10 microM), or prostaglandin E2 (30 nM). The inhibiting effect of triamcinolone on osmotic glial cell swelling was mediated by stimulation of transporter-mediated release of endogenous adenosine and subsequent A1 receptor activation, resulting in an elevation of the intracellular cAMP level and activation of the protein kinase A, and, finally, in an opening of extrusion pathways for K+ and Cl- ions. The inhibitory effect on the cytotoxic swelling of glial cells may contribute to the fast edema-resolving effect of vitreal triamcinolone observed in human patients.

Intravitreal triamcinolone acetonide for treatment of intraocular proliferative, exudative, and neovascular diseases

Within the last three years, triamcinolone acetonide has increasingly been applied intravitreally as treatment option for various intraocular neovascular edematous and proliferative disorders. The best response in terms of gain in visual acuity after the intravitreal injection of triamcinolone acetonide was found in eyes with intraretinal edematous diseases such as diffuse diabetic macular edema, branch retinal vein occlusion, central retinal vein occlusion, and pseudophakic cystoid macular edema. Visual acuity increased and degree of intraocular inflammation decreased in eyes with various types of non-infectious uveitis including acute or chronic sympathetic ophthalmia and Adamantiadis-Behcet's disease. Intravitreal triamcinolone may be useful as angiostatic therapy in eyes with iris neovascularization and proliferative ischemic retinopathies. Possibly, intravitreal triamcinolone may be helpful as adjunct therapy for exudative age-related macular degeneration, possibly in combination with photodynamic therapy. In eyes with chronic, therapy resistant, ocular hypotony, intravitreal triamcinolone can induce an increase in intraocular pressure and may stabilize the eye. The complications of intravitreal triamcinolone therapy include secondary ocular hypertension in about 40% of the eyes injected, cataractogenesis, postoperative infectious and non-infectious endophthalmitis, and pseudo-endophthalmitis. Intravitreal triamcinolone injection can be combined with other intraocular surgeries including cataract surgery. Cataract surgery performed some months after the injection does not show a markedly elevated rate of complications. If vision increases and eventually decreases again after an intravitreal triamcinolone acetonide injection, the injection can be repeated. The duration of the effect of a single intravitreal injection of triamcinolone depended on the dosage given. Given in a dosage of about 20mg to non-vitrectomized eyes, the duration of the effect and of the side-effects was 6-9 months. Intravitreal triamcinolone acetonide may offer a possibility for adjunctive treatment of intraocular edematous and neovascular disorders. One has to take into account the side-effects and the lack of long-term follow-up observations.

Regression of serous macular detachment after intravitreal triamcinolone acetonide in patients with diabetic macular edema

PURPOSE

To evaluate the effect of intravitreal triamcinolone acetonide on serous macular detachment in eyes with diabetic macular edema.

DESIGN

Interventional case series.

METHODS

The study population comprised twenty eyes of 20 patients with diabetic macular edema (12 men, eight women), aged 48 to 76 years. The eligibility criteria for this study included clinically detectable macular edema in which the presence of serous macular detachment was documented by optical coherence tomography. After intravitreal injection of 0.1 ml (4 mg) triamcinolone acetonide, visual and anatomic responses were observed.

RESULTS

In all eyes, after an injection of triamcinolone acetonide, macular edema and serous macular detachment regressed. At 3 and 6 months, macular edema and serous macular detachment had recurred in eight (40%) and nine eyes (45%), respectively. Patients with recurrence were re-treated. No eyes lost vision at 1 month, and all eyes showed improvement. At 3 months, no eyes had lost vision from baseline, and 17 eyes (85%) showed improvement. At 6 months, again no eyes had lost vision from baseline, and 16 eyes (80%) maintained improved visual acuity.

CONCLUSION

Intravitreal triamcinolone acetonide is an effective treatment for serous macular detachment in patients with diabetic macular edema.

Trans-Tenon's retrobulbar triamcinolone acetonide infusion for refractory diabetic macular edema after vitrectomy

PURPOSE

To evaluate the efficacy and safety of trans-Tenon's retrobulbar triamcinolone acetonide (TA) infusion for the treatment of refractory diabetic macular edema (DME) after vitrectomy.

METHODS

After topical anesthesia, 20 eyes from 20 patients with persistent DME after pars plana vitrectomy were treated with trans-Tenon's retrobulbar infusion of 40 mg TA through an inferotemporal approach. The mean duration (+/-SD) between vitrectomy and trans-Tenon's retrobulbar TA infusion was 11.4+/-7.9 months. The mean follow-up period (+/-SD) after trans-Tenon's retrobulbar TA infusion was 13.3+/-2.8 months.

RESULTS

At 1 week after trans-Tenon's retrobulbar TA infusion, the mean central retinal thickness (+/-SD) measured by optical coherence tomography was 381+/-99 mum, which was a statistically significant decrease in comparison with the preoperative thickness (555+/-112 mum) (P<0.001). Additional trans-Tenon's retrobulbar TA infusions were performed in ten eyes (50%), due to the recurrence of DME at 6.6+/-3.0 months after the first TA infusion. At the final examination, macular edema resolved in 13 (65%), improved in four (20%), and remained unchanged in three (15%) of the 20 eyes. At 1 month after trans-Tenon's retrobulbar TA infusion, the mean laser flare value (+/-SD) was 9.6+/-3.0 photon/ms, which was a statistically significant decrease in comparison with the preoperative value (15.5+/-5.9 photon/ms) (P<0.01). Furthermore, in ten eyes (50%) with recurrent DME, re-elevated laser flare values were observed prior to the recurrence of DME. The final best-corrected Snellen visual acuity improved by two or more lines in nine eyes (45%), and remained unchanged in 11 eyes (55.0%). IOP elevation equal to or higher than 21 mmHg was observed in three (15%) of the 20 eyes with TA infusion, and was controlled by topical medications. No other injection-related complications were observed.

CONCLUSION

Trans-Tenon's retrobulbar TA infusion is an effective and safe method for the treatment of refractory DME, which is present even after vitrectomy.

Verteporfin therapy in combination with triamcinolone: published studies investigating a potential synergistic effect

Evidence from randomized, placebo-controlled, double-masked studies has demonstrated that verteporfin (Visudyne) therapy is effective in reducing the risk of visual acuity loss in selected groups of patients with choroidal neovascularization (CNV) due to age-related macular degeneration (AMD). Pilot studies of intravitreal triamcinolone acetonide monotherapy revealed promising results in patients with CNV due to AMD, but the visual acuity outcomes in a randomized, controlled study were lower than anticipated. Recently, however, there has been growing interest in the adjunctive use of triamcinolone to improve visual acuity and reduce regrowth of CNV in patients receiving verteporfin therapy. This review article surveys the currently available evidence, based on a Medline search covering the years 1980-2005 and abstracts from recent scientific meetings. A number of small-scale, uncontrolled pilot studies have indicated that the combination of triamcinolone acetonide with verteporfin therapy may be beneficial. Evidence is now needed from randomized, controlled studies to determine whether the potential benefits of combination therapy outweigh the possible risks of increased intraocular pressure, endophthalmitis, and progression of cataract that have been observed in trials of triamcinolone monotherapy.

Molecular endocrinology and physiology of the aging central nervous system

Aging is associated with a progressive decline in physical and cognitive functions. The impact of age-dependent endocrine changes regulated by the central nervous system on the dynamics of neuronal behavior, neurodegeneration, cognition, biological rhythms, sexual behavior, and metabolism are reviewed. We also briefly review how functional deficits associated with increases in glucocorticoids and cytokines and declining production of sex steroids, GH, and IGF are likely exacerbated by age-dependent molecular misreading and alterations in components of signal transduction pathways and transcription factors.

Pharmacotherapy for diabetic retinopathy

PURPOSE OF REVIEW

Diabetic retinopathy (DR) is a potentially visually devastating complication of chronic hyperglycemia and other associated systemic abnormalities. Numerous large, prospective, randomized clinical trials have delineated the current standard prevention and treatment protocols including intensive glycemic and blood pressure control and laser photocoagulation for neovascularization and clinically significant macular edema. However, despite standard intervention, vision loss from DR still occurs at an alarming rate. Thus, more recently, researchers have directed their efforts towards better understanding the microscopic changes occurring in DR to develop more effective pharmacologic prevention and treatment strategies.

RECENT FINDINGS

Phase II and III clinical studies involving antivascular endothelial growth factor (VEGF) and protein kinase C (PKC) inhibitors for the management of diabetic macular edema are underway. Researchers recently found elevated pigment endothelium-derived factor (PEDF) associated with active neovascularization, a finding that counteracts prior claims of endogenous anti-angiogenic properties. Other clinical trials are underway to evaluate the efficacy of octreotide, celecoxib, and candesartan on DR. Small clinical studies have suggested beneficial treatment effects for triamcinolone acetonide, interferon alpha-2a, and supplemental oxygen; however, other studies involving losartan, vitamins C and E, and atorvastatin failed to show any benefit.

SUMMARY

Over the past decade, numerous animal models have led to a more thorough understanding of the early microvascular alterations and later neovascularization and edema observed in DR. These discoveries and subsequent human clinical studies involving direct and indirect growth factor modulation, extracellular matrix alteration, vitreolysis, and alternative DR pathways including dyslipidemia, hypoxia, and sorbitol are reviewed in this manuscript.

Pathomechanisms of Cystoid Macular Edema

Cystoid macular edema (CME) is a well-known endpoint of various ocular diseases, but the relative pathogenic impact of extra- and intracellular fluid accumulation within the retinal tissue still remains uncertain. While most authors favor an extracellular fluid accumulation as the main causative factor of cyst formation, there are indications that Müller cell swelling may also contribute to CME development (particularly in cases without significant angiographic vascular leakage). Vascular leakage occurs after a breakdown of the blood-retinal barrier during traumatic, vascular, and inflammatory ocular diseases, and allows the serum to get into the retinal interstitium. Since intraretinal fluid distribution is restricted by two diffusion barriers, the inner and outer plexiform layers, serum leakage from intraretinal vessels causes cysts mainly in the inner nuclear layer while leakage from choroid/pigment epithelium generates (in addition to subretinal fluid accumulation) cyst formation in the Henle fiber layer. In the normal healthy retina, the transretinal water fluxes are mediated by glial and pigment epithelial cells. These water fluxes are inevitably coupled to fluxes of osmolytes; in the case of glial (Müller) cells, to K(+) clearance currents. For this purpose, the cells express a complex, microtopographically optimized pattern of transporters and channels for osmolytes and water in their plasma membrane. Ischemic/hypoxic alterations of the retinal microvasculature result in gliotic responses which involve down-regulation of K(+) channels in the perivascular Müller cell end-feet. This means a closure of the main pathway which normally generates the osmotic drive for the redistribution of water from the inner retina into the blood. The result is an intracellular K(+) accumulation which, then, osmotically drives water from the blood into the glial cells (i.e., in the opposite direction) and causes glial cell swelling, edema, and cyst formation. While the underlying mechanisms await further research, it is expected that their improved knowledge will stimulate the development of novel therapeutic approaches to resolve edema in retinal tissue.

Conditioned medium from mixed retinal pigmented epithelium and Müller cell cultures reduces in vitro permeability of retinal vascular endothelial cells

AIM

To investigate the in vitro effect of laser photocoagulation on blood-retinal barrier permeability.

METHODS

Retinal capillary endothelial cells were exposed to supernatants from long term co-cultured cells that were argon laser treated. Endothelial cell permeability was analysed by (1) measurement of transendothelial electrical resistance and (2) equilibration of [(3)H] inulin and [(14)C] albumin across the cell monolayer.

RESULTS

Laser photocoagulation of various retinal cells and control ECV304 cells in the lower chamber did not appreciably improve permeability of the endothelial cell monolayer compared with that of unlasered cells. However, medium that was conditioned by mixed retinal pigmented epithelium and Müller cells significantly reduced both inulin (43.2% (SD 6.5%) equilibration in mixed cultures v 59.8% (SD 7.0%) control cells, p<0.05) and albumin (15.1% (SD 3.8%) v 31.1% (SD 6.7%), p<0.05) permeability of the endothelial cell monolayers. A fourfold increase in transendothelial electrical resistance was also seen.

CONCLUSIONS

These results are consistent with the hypothesis that interaction of Müller cells with retinal pigmented epithelium induced by laser treatment results in secretion of soluble factor(s), which reduces permeability of retinal vascular endothelium. Identification of these factor(s) may have implications for the clinical treatment of macular oedema secondary to diabetic retinopathy and other diseases.

A review of treatments for macular degeneration: a synopsis of currently approved treatments and ongoing clinical trials

PURPOSE OF REVIEW

The purpose of this report is to review recent literature and ongoing clinical trials of the treatment of neovascular age-related macular degeneration.

RECENT FINDINGS

Advances in the understanding of the pathogenesis of age-related macular degeneration and choroidal neovascularization have resulted in the emergence of pharmacotherapies targeting various aspects of angiogenesis. Preliminary results with the new agents have been encouraging. Moreover, longer follow-up and subgroup analyses of the Treatment of Age-Related Macular Degeneration with Photodynamic Therapy and Verteporfin in Photodynamic Therapy studies have suggested new potential indications for photodynamic therapy.

SUMMARY

Currently a patient with wet macular degeneration may have multiple investigational options that were unavailable several years ago. Ongoing clinical trials are aimed at determining the long-term safety and efficacy of these new pharmacologic and combination therapy modalities.

Corticosteroids in posterior segment disease: an update on new delivery systems and new indications

PURPOSE OF REVIEW

Corticosteroids are traditionally used for inflammatory disorders because of their ability to diminish neutrophil transmigration, limit access to sites of inflammation, and decrease cytokine production. More recently, however, investigators have focused on the angiostatic and antipermeability properties of corticosteroids for posterior segment diseases such as age-related macular degeneration (AMD), diabetic retinopathy, and macular edema. Both new angiostatic and traditional corticosteroids are currently undergoing evaluation as new delivery techniques such as intravitreal injection and intraocular sustained-release devices facilitate high local angiostatic and antipermeability concentrations while minimizing extraocular toxicity. The purpose of this review is to discuss recent work concerning both the mechanism and effectiveness of these newer treatments.

RECENT FINDINGS

Steroids may exert a beneficial effect in AMD-related choroidal neovascular membranes (CNVM) through inhibition of CNVM-promoting macrophages and direct inhibition of angiogenic growth factors. They may also alter extracellular matrix turnover and inhibit matrix metalloproteinases involved in CNVM formation. Intravitreal steroid injections potently inhibit experimental CNVM in primates and rats and have shown promise in some early human pilot trials. In proliferative diabetic retinopathy, steroids may directly inhibit growth factors such as vascular endothelial derived growth factor and inhibit leukocytes that play an important role in early microvascular alterations. Intravitreal steroid injections inhibit experimental preretinal neovascularization in pigs and rats, and rubeosis in some early human studies. In addition, the effect of steroids on vascular permeability has led to their use for macular edema from many causes such as diabetes and venous occlusive disease.

SUMMARY

The use of steroids to treat a number of retinal diseases is gaining wide spread acceptance. The apparent short-term success must be balanced by the fact that the long-term safety and efficacy have yet to be determined for any of these approaches. A number of large randomized prospective clinical trials of steroid compounds and new delivery systems are currently under way for AMD, diabetic retinopathy, uveitis, and other retinovascular diseases, and hopefully these studies will provide guidance about the use of these new modalities.

Intravitreal triamcinolone does not alter basal vascular endothelial growth factor mRNA expression in rat retina

Intravitreal triamcinolone inhibits choroidal neovascularization. To investigate if vascular endothelial growth factor (VEGF) is affected, we examined VEGF expression after intravitreal triamcinolone administration in rat retina. Using in situ hybridization, we have found dense clustered VEGF mRNA signals in the retinal pigment epithelium, moderate patchy signals in the inner nuclear layer, and positive labeling in a sub-population of ganglion cells. Densitometry and northern blot analysis revealed no significant alteration of VEGF mRNA expression pattern and level 3-21 days after triamcinolone injection. Our data indicate that intravitreal triamcinolone does not affect basal VEGF mRNA expression in normal adult rat retina.

Choroidal neovascularization

PURPOSE

To review clinicopathologic findings of choroidal neovascularization (CNV) in a historical framework with emphasis on pathobiology and correlation with treatment.

DESIGN

Selective literature review combined with authors' experience.

RESULTS

Choroidal neovascularization represents a stereotypic, nonspecific response to a specific stimulus. Although CNV differs among patients, the general growth patterns are subretinal pigment epithelium (type 1), subretinal (type 2), or combined. Choroidal neovascularization occurs over time in dynamic stages of initiation, active and involutional. Treatments are now being designed based on modern understanding of CNV growth.

CONCLUSIONS

Progress continues to be made concerning understanding the pathobiology and treatment of CNV.