ISIS-DME: A Prospective, Randomized, Dose-Escalation Intravitreal Steroid Injection Study for Refractory Diabetic Macular Edema

Current Treatments for Diabetic Macular Edema

Diabetic retinopathy is a major retinal disorder and a leading cause of blindness. Diabetic macular edema (DME) is an ocular complication in patients with diabetes, and it can impair vision significantly. DME is a disorder of the neurovascular system, and it causes obstructions of the retinal capillaries, damage of the blood vessels, and hyperpermeability due to the expression and action of vascular endothelial growth factor (VEGF). These changes result in hemorrhages and leakages of the serous components of blood that result in failures of the neurovascular units (NVUs). Persistent edema of the retina around the macula causes damage to the neural cells that constitute the NVUs resulting in diabetic neuropathy of the retina and a reduction in vision quality. The macular edema and NVU disorders can be monitored by optical coherence tomography (OCT). Neuronal cell death and axonal degeneration are irreversible, and their development can result in permanent visual loss. Treating the edema before these changes are detected in the OCT images is necessary for neuroprotection and maintenance of good vision. This review describes the effective treatments for the macular edema that are therefore neuroprotective.

Intravitreal corticosteroids for diabetic macular edema: a network meta-analysis of randomized controlled trials

BACKGROUND

To evaluate the efficacy and safety of different intravitreal corticosteroids for treating diabetic macular edema (DME).

METHODS

Four databases were systematically searched for randomized controlled trials comparing different intravitreal corticosteroids for treating DME. The primary outcome was the change in best-corrected visual acuity (BCVA) within 6 months after the first injection (short-term BCVA). Secondary outcomes were the change in BCVA over 1 year (long-term BCVA) and changes in central macular thickness (CMT) and intraocular pressure (IOP) within 6 months after the first injection. Network meta-analysis was performed to aggregate the results from the individual studies.

RESULTS

Nineteen trials involving 2839 eyes were included. Intravitreal triamcinolone acetonide (TA) injections (≥ 8 mg and 4-8 mg), fluocinolone acetonide (FA) implants (0.5 µg/day) and dexamethasone (DEX) implants (700 µg) improved short-term BCVA (mean changes in logMAR [95% confidence interval] - 0.27 [- 0.40, - 0.15]; - 0.12 [- 0.18, - 0.06]; - 0.10 [- 0.21, - 0.01]; and - 0.06 [- 0.11, - 0.01]). Intravitreal TA injections (4 mg, multiple times), FA implants (0.5 µg/day and 0.2 µg/day), and DEX implants (350 µg) improved long-term BCVA (mean changes in logMAR [95% confidence interval] - 0.11 [- 0.21, - 0.02]; - 0.09 [- 0.15, - 0.03]; - 0.09 [- 0.14, - 0.02]; and - 0.04 [- 0.07, - 0.01]). All intravitreal corticosteroids reduced CMT, and different dosages of TA did not show significant differences in increasing IOP.

CONCLUSIONS

Intravitreal corticosteroids effectively improved BCVA in DME patients, with higher dosages showing greater efficacies. TA was not inferior to FA or DEX and may be considered a low-cost alternative choice for DME patients. The long-term efficacy and safety of different corticosteroids deserve further investigation. Trial registration Prospectively registered: PROSPERO, CRD42020219870.

Expression of microRNA-155-5p in patients with refractory diabetic macular edema and its regulatory mechanism

Diabetic macular edema (DME) is the main cause of visual impairment in diabetic patients, but its pathogenesis remains unclear. The purpose of the present study was to analyze the expression of microRNA (miR)-155-5p in patients with DME and its regulatory mechanism. A total of 72 patients diagnosed with DME and 17 with idiopathic macular hole (MH) were recruited. Among samples from patients with DME, 45 were DME and 27 were refractory DME, whereas patients with idiopathic MH served as the control group. Optical coherence tomography and fundus photograph analysis revealed that part of the retina in the fundus of patients with DME was thickened, with macular edema occurring simultaneously. In refractory patients with DME, macular edema was associated with bleeding and a dark cavity between retinal layers. Through reverse transcription-quantitative PCR analysis, miR-155-5p was highly expressed in the aqueous humor (AH) and plasma of patients with DME compared with that in patients with MH, and this was even higher in the refractory DME group. Upon analyzing patient clinical data, the difference in miR-155-5p expression in the AH and plasma was positively associated with disease course, body mass index, fasting blood-glucose, glycated hemoglobin, proteinuria and glycosuria. The expression of miR-155-5p was not significantly different based on hemoglobin, intraocular pressure and sex. The aforementioned results indicate that miR-155-5p might promote the development of DME. To further study the molecular mechanism, human retinal microvascular endothelial cells (HRMECs) were cultured and treated with high glucose in vitro. The results showed that miR-155-5p expression was significantly upregulated in HRMECs induced by high glucose. After inhibiting the expression of miR-155-5p, cell proliferation, angiogenesis and VEGF protein levels were significantly downregulated, whereas miR-155-5p mimics had the opposite effect. In summary, miR-155-5p is closely associated with DME and is a potential target for refractory DME treatment.

Ocular hypertension following 40 mg sub-Tenon triamcinolone versus 0.7 mg dexamethasone implant versus 2 mg intravitreal triamcinolone

OBJECTIVE

To compare rates of ocular hypertension (OHT) in eyes receiving 40 mg sub-Tenon triamcinolone (STT), 0.7 mg dexamethasone implant (DEX), and 2 mg intravitreal triamcinolone (IVT).

METHODS

This study is a single-centre, retrospective case series. All patients receiving STT and DEX between 4/1/2014 and 3/1/2017 and IVT between 3/1/2012 and 3/1/2017 with a minimum of 3 months' follow-up were included. OHT was defined as an intraocular pressure (IOP) >24 mm Hg. Patients receiving any other form of topical, oral, or intravitreal steroid were excluded.

RESULTS

113 eyes from 104 patients in the STT group, 122 eyes from 109 patients in the DEX group, and 109 eyes from 103 patients in the IVT group were included. The mean number of injections for each eye was 1.7 in the STT group, 2.6 for the DEX group, and 2.8 for the IVT group (p < 0.001). Twenty eyes (17.7%) developed OHT in the STT group, 19 eyes (15.6%) developed OHT in the DEX group, and 14 eyes (12.8%) developed OHT in the IVT group (p = 0.60). IOP was controlled in all eyes with observation, topical IOP-lowering medication, or surgical intervention. The rate of incisional glaucoma surgery was 1.7% in the STT group, 1.6% in the DEX group, and 0% in the IVT group (p = 0.55).

CONCLUSIONS

The rate of OHT was similar across treatment groups. The proportion of OHT in patients with a history of glaucoma was no different from that in patients without a history of glaucoma. All cases were successfully managed with observation, medical treatment, or incisional surgery.

Cost Effectiveness of Treatments for Diabetic Retinopathy: A Systematic Literature Review

BACKGROUND

Diabetic retinopathy (DR) affects approximately one-third of people diagnosed with diabetes, can be sight-threatening, and generates significant human and economic burden. Over the last 2 decades, newer therapies have emerged, offering significant clinical benefits, however at a cost. Given the scarcity of available budgets, the cost effectiveness of these newer treatments is of vital importance to policy makers.

METHODS

A systematic review was conducted in the PubMed, EMBASE, Cochrane, HEED and CRD databases to find and evaluate economic evaluations assessing the cost effectiveness of alterative DR treatments. Studies were assessed for their eligibility, findings and quality, and are presented in this systematic review.

RESULTS

Of the 5254 studies retrieved from the literature search, 17 were included in this review. For patients with proliferative DR, when early pars plana vitrectomy was compared with pan-retinal laser photocoagulation, similar cost per quality-adjusted life-year (QALY) was observed between the two. Treatment with either intravitreal ranibizumab (IVR) or intravitreal bevacizumab (IVB) falls within acceptable cost-effectiveness thresholds in the diabetic macular oedema (DMO) population; however, in the non-DMO population, the marginal benefit of IVR or IVB in relation to the marginal cost relative to laser does not justify their use. Among the anti-vascular endothelial growth factor (VEGF) therapies, IVB appears more attractive from an economic point of view due to its lower cost. For patients with DMO, studies indicate that a combination therapy of IVR or IVB with laser and, to a lesser degree, as monotherapy, are cost effective relative to laser monotherapy; IVR plus laser is cost effective relative to laser plus triamcinolone; and laser combined with triamcinolone injections is reportedly more cost effective over IVR for pseudophakic eyes only. Moreover, fluocinolone implants appear cost effective compared with sham implants, or when treating refractory DMO. IVR administered either pro re nata (PRN) or as 'treat and extend' dominated intravitreal aflibercept (IVA) in a few studies. On the other hand, IVR monotherapy or with laser (as well as IVA) does not compare favourably relative to IVB monotherapy or with laser.

CONCLUSIONS

Interpretation of cost-effectiveness data should be treated with caution in this case; details of the therapeutic regimen, such as dosage and frequency, and clinical efficacy of the treatments should be considered in relation to policy-making decisions. Given the scarcity of resources, the ever-increasing significance of health technology assessment, and the substantial differences in the methodologies of the studies presented in this review, there is a pressing need for more advanced and standardised approaches to assessing the effectiveness and cost effectiveness of the emerging anti-VEGF pharmacotherapies for the treatment of DMO.

Long-term effect of triamcinolone acetonide in the treatment of upper lid retraction with thyroid associated ophthalmopathy

AIM

To report the long-term outcomes of a large cohort of upper lid retraction patients treated with subconjunctival triamcinolone acetonide injections.

METHODS

This retrospective clinical study was conducted from 2009 to 2016. The documents of 97 patients (126 eyes) were reviewed. The patients were treated with subconjunctival triamcinolone acetonide injections monthly and evaluated pre- and post-treatment by taking measurements of the upper margin reflex distance (MRD1, the distance between the upper-lid margin and the pupil center), lid aperture, lagophthalmos and proptosis. The patients were divided into the cured group, the improved group and the ineffective group based on the final treatment effectiveness. The improved group and the ineffective group were combined into non-cured group.

RESULTS

The follow-up time was 23.45±14.86mo. Of the patients, 63 (64.9%) were assigned to the cured group, 22 (22.7%) in the improved group, 12 (12.4%) in the ineffective group. Injection times for cured group was 4.66±1.74, and for non-cured group was 5.17±2.08 (P≤0.05). The MRD1 was significantly reduced between baseline and 1mo after the initiation of treatment in the cured and improved groups (P<0.001). The values did not change significantly after 4mo for the improved group, while they continued to decrease in the cured group. In the ineffective group, the MRD1 did not significantly change after treatment. A statistically significant difference was observed between the baseline and post-treatment values of the mean muscle thickness (2.95±0.99 mm vs 2.04±0.63 mm, P<0.05) and surface area (27.27±10.5 mm²vs 18.3±7.04 mm², P<0.05) of the levator superioris with magnetic resonance imaging examination. Twelve patients (12.4%) relapsed after treatment and required additional subconjunctival injections. The main side effects included menstrual cycle disturbances (32%) and elevations of intra-ocular pressure (18.6%).

CONCLUSION

A repeated subconjunctival injection of triamcinolone is an effective and relatively safe treatment for upper lid retraction due to thyroid-associated ophthalmopathy. This is related to the anti-inflammation effect of the medicine and the levator thickness can become thinner. Patients must be monitored regularly for recurrences and side effects.

Characterization and Pharmacokinetics of Triamcinolone Acetonide-Loaded Liposomes Topical Formulations for Vitreoretinal Drug Delivery

PURPOSE

To achieve a safer alternative to intravitreal injection of corticosteroids, we developed and characterized triamcinolone acetonide-loaded liposomes formulations (TA-LFs) to be used topically for vitreoretinal drug delivery.

METHODS

Four different 0.2% TA-LFs (TA-LF1 to TA-LF4) were generated and submitted to physicochemical characterization. Posteriorly, an ex vivo diffusion assay was performed using rabbit corneas as membranes. Finally, concentrations of triamcinolone acetonide (TA) were determined by high-performance liquid chromatography in ocular tissues from New Zealand white rabbits after multiple topical doses of TA-LF2 (6 times per day, 14 days). In addition, toxicity and tolerability of TA-LF2 was evaluated by cell viability assay and eye examination of study animals, respectively.

RESULTS

TA-LF2 was the most stable formulation maintaining a stable hidrogenion potential (pH) at 30 and 40°C and even improving encapsulation with higher temperature. TA-LF2 and TA-LF3 presented the best diffusion performance in vitro reaching the highest TA concentrations after 8 h of follow-up. In vivo diffusion and pharmacokinetics analysis showed that concentrations of TA in retina and vitreous reached the highest peak at 12 h after topical administration of TA-LF2 (252.10 ± 90.00 ng/g and 32.6 ± 10.27 ng/g, respectively) and subsequently decline to 24.0 ± 11.72 ng/g and 19.5 ± 13.14 ng/g, respectively, at 14 days of follow-up. Finally, cell viability was unaffected by TA-LF2, and no increase in intraocular pressure nor ocular alterations were observed after topical administration of this formulation in rabbits.

CONCLUSION

TA-loaded liposomes, administered topically, can deliver TA in the vitreous cavity and reach the retina efficiently.

Current Advances in Pharmacotherapy and Technology for Diabetic Retinopathy: A Systematic Review

Diabetic retinopathy (DR) is classically defined by its vascular lesions and damage in the neurons of the retina. The cellular and clinical elements of DR have many features of chronic inflammation. Understanding the individual cell-specific inflammatory changes in the retina may lead to novel therapeutic approaches to prevent vision loss. The systematic use of available pharmacotherapy has been reported as a useful adjunct tool to laser photocoagulation, a gold standard therapy for DR. Direct injections or intravitreal anti-inflammatory and antiangiogenesis agents are widely used pharmacotherapy to effectively treat DR and diabetic macular edema (DME). However, their effectiveness is short term, and the delivery system is often associated with adverse effects, such as cataract and increased intraocular pressure. Further, systemic agents (particularly hypoglycemic, hypolipidemic, and antihypertensive agents) and plants-based drugs have also provided promising treatment in the progression of DR. Recently, advancements in pluripotent stem cells technology enable restoration of retinal functionalities after transplantation of these cells into animals with retinal degeneration. This review paper summarizes the developments in the current and potential pharmacotherapy and therapeutic technology of DR. Literature search was done on online databases, PubMed, Google Scholar, clinitrials.gov, and browsing through individual ophthalmology journals and leading pharmaceutical company websites.

Episcleral drug film for better-targeted ocular drug delivery and controlled release using multilayered poly-ε-caprolactone (PCL)

Triamcinolone acetonide (TA) and poly-ε-caprolactone (PCL) were engineered into a micro drug film for episcleral application to better manage chronic vitreoretinal diseases such as proliferative vitreoretinopathy (PVR). Compared to an intravitreal drug injection, this drug film is much safer without breaking into ocular barriers. Compared to a traditional subtenon injection, this drug film demonstrated superior therapeutic duration, better drug bioavailability in the choroid and retina, and better-targeted drug delivery ability. The rabbit eye study demonstrated that using the PCL-TA film led to 5.6 and 3.4 times higher drug AUC in the choroid and the retina respectively than in eyes following a subtenon drug injection. The mean drug residence time in the rabbit choroid was also doubled by using the episcleral TA film (86days versus 43days). Remaining TA in the drug film was consistently higher than that in the subtenon space, indicating controlled release of TA by the PCL-TA film. The pharmacokinetics of triamcinolone in the choroid and retina were optimized from typical first-order kinetics to a more sustained release by use of this film. This episcleral film system worked better on rabbit eyes than on guinea pig eyes, indicating that scleral thickness and eye size may be crucial aspects to consider when choosing an animal model or when designing a transscleral delivery device for human use. This engineered drug film may be very useful in preventing and managing PVR associated with open globe trauma or surgical repair for retinal detachment.

STATEMENT OF SIGNIFICANCE

This study demonstrated a novel micro episcleral drug film that is made from the engineering of triamcinolone acetonide (TA) into poly-ε-caprolactone (PCL). The film can be conveniently placed at the injury or disease site during primary surgery and provide controlled release of TA for four months that covers the high-risk time window for developing proliferative vitreoretinopathy (PVR). This engineered drug film may be very useful in preventing and managing PVR associated with open globe trauma or intraocular surgery.

Current trends in the monitoring and treatment of diabetic retinopathy in young adults

The diagnosis and treatment of diabetic retinopathy (DR) in young adults have significantly improved in recent years. Research methods have widened significantly, for example, by introducing spectral optical tomography of the eye. Invasive diagnostics, for example, fluorescein angiography, are done less frequently. The early introduction of an insulin pump to improve the administration of insulin is likely to delay the development of diabetic retinopathy, which is particularly important for young patients with type 1 diabetes mellitus (T1DM). The first years of diabetes occurring during childhood and youth are the most appropriate to introduce proper therapeutic intervention before any irreversible changes in the eyes appear. The treatment of DR includes increased metabolic control, laserotherapy, pharmacological treatment (antiangiogenic and anti-inflammatory treatment, enzymatic vitreolysis, and intravitreal injections), and surgery. This paper summarizes the up-to-date developments in the diagnostics and treatment of DR. In the literature search, authors used online databases, PubMed, and clinitrials.gov and browsed through individual ophthalmology journals, books, and leading pharmaceutical company websites.

Differential flow rate of commercially available triamcinolone with and without preservative through small-gauge needles

OBJECTIVE

To compare the flow rate through different gauge needles of triamcinolone acetonide with benzyl alcohol (TABA) versus preservative-free triamcinolone acetonide injectable suspension (TAIS).

MATERIALS AND METHODS

Experimental injections of 1 mL of TABA or TAIS were performed through a 27-, 30-, or 32-gauge needle. A piezoelectric pressure transducer connected to a personal computer was placed between the syringe and needle to record the force-time relationship and assess the flow rate (mL/s). Measurements were performed in triplicate.

RESULTS

Flow rates were similar between preparations using a 27-gauge needle. Using a 30-gauge needle, the flow rate was 0.058 mL/s for TABA and 0.178 mL/s for TAIS. Using a 32-gauge needle, no flow was sustained by TABA, whereas the flow rate of TAIS was 0.114 mL/s (P < .05).

CONCLUSION

TAIS can be injected through a 32-gauge needle without the risk of obstruction. Occlusions were seen with TABA using the 30- and 32-gauge needles.

Intravitreal steroids for the treatment of retinal diseases

Diabetic macular edema (DME), pseudophakic cystoid macular edema (CME), age-related macular degeneration (AMD), retinal vascular occlusion (RVO), and uveitis are ocular conditions related to severe visual impairment worldwide. Corticosteroids have been widely used in the treatment of these retinal diseases, due to their well-known antiangiogenic, antiedematous, and anti-inflammatory properties. Intravitreal steroids have emerged as novel and essential tools in the ophthalmologist's armamentarium, allowing for maximization of drug efficacy and limited risk of systemic side effects. Recent advances in ocular drug delivery methods led to the development of intraocular implants, which help to provide prolonged treatment with controlled drug release. Moreover, they may add some potential advantages over traditional intraocular injections by delivering certain rates of drug directly to the site of action, amplifying the drug's half-life, contributing in the minimization of peak plasma levels of the drug, and avoiding the side effects associated with repeated intravitreal injections. The purpose of this review is to provide an update on the use of intravitreal steroids as a treatment option for a variety of retinal diseases and to review the current literature considering their properties, safety, and adverse events.

Sustained release of triamcinolone acetonide from an episcleral plaque of multilayered poly-ε-caprolactone matrix

A subtenon injection of triamcinolone acetonide (TA) is a widely used treatment modality for various chorio-retinal diseases. Although it is less invasive than intravitreal injection, it can produce dose-associated ocular complications and has the disadvantages associated with systemic TA exposure. In this study we have developed and evaluated an episcleral film consisting of TA and poly-ε-caprolactone (PCL). The films were prepared by spraying a mixture of PCL in dichloromethane and TA in acetone. The films were produced as 6mm wide and 12 mm long episcleral plaques. X-ray diffraction demonstrated an even distribution of TA crystals in PCL, although the TA was less crystalized than a native TA control. Fourier transform infrared spectroscopy revealed effective integration of TA within the PCL matrix. An in vitro study of the release of TA from the episcleral plaques showed that TA release rate was only 40-50% that of the equivalent native TA control. An in vivo study demonstrated that the plaques were well tolerated in rabbit eyes with significantly less systemic TA exposure. The episcleral plaques provided therapeutic vitreous TA levels for 3 months, while TA levels in the vitreous were detectable for only 1 month following an equivalent dose by subtenon TA injection. The PCL-TA 30-60 episcleral plaque may be further developed as a better alternative treatment for many chronic vitreo-retinal diseases, providing longer and controlled release and fewer drug-associated complications than those associated with a conventional subtenon injection of TA.

Diabetic retinopathy: current concepts and emerging therapy

More Americans become blind each year from microvascular complications of diabetes than from any other cause. Several studies have indicated that tight glucose control and lifestyle modification can dramatically reduce the incidence and prevalence of diabetic retinopathy. Research over the past several years has yielded a tremendous increase in our knowledge of the pathogenesis of the damage to the retina that occurs in diabetes and has facilitated our ability to intervene and control the damage. New intravitreal medical therapies supported by government- and industry-supported research are gradually replacing standard laser photocoagulation for the treatment of all forms of retinopathy.

Fluocinolone acetonide intravitreal implant for the treatment of diabetic macular edema

Diabetic macular edema (DME) remains one of the leading causes of moderate to severe vision loss. Although laser photocoagulation was the standard of care for several years, few patients achieved significant improvements in visual acuity. As a result, several pharmacotherapies and surgeries have been investigated. The fluocinolone acetonide devices are one of the latest therapies considered for the treatment of DME. Despite bringing significant improvements in visual acuity, fluocinolone devices are associated with cataract formation, increased intraocular pressure (IOP), and surgery to lower IOP. Due to the risk of complications, fluocinolone acetonide devices should be considered only in cases refractive to first-line therapies. In this review, we evaluate current and emerging therapies for DME, with special emphasis on fluocinolone acetonide intravitreal devices.

Current treatments in diabetic macular oedema: systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review is to appraise the evidence for the use of anti-VEGF drugs and steroids in diabetic macular oedema (DMO) as assessed by change in best corrected visual acuity (BCVA), central macular thickness and adverse events

DATA SOURCE

MEDLINE, EMBASE, Web of Science with Conference Proceedings and the Cochrane Library (inception to July 2012). Certain conference abstracts and drug regulatory web sites were also searched.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS

Randomised controlled trials were used to assess clinical effectiveness and observational trials were used for safety. Trials which assessed triamcinolone, dexamethasone, fluocinolone, bevacizumab, ranibizumab, pegaptanib or aflibercept in patients with DMO were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

Risk of bias was assessed using the Cochrane risk of bias tool. Study results are narratively described and, where appropriate, data were pooled using random effects meta-analysis.

RESULTS

Anti-VEGF drugs are effective compared to both laser and placebo and seem to be more effective than steroids in improving BCVA. They have been shown to be safe in the short term but require frequent injections. Studies assessing steroids (triamcinolone, dexamethasone and fluocinolone) have reported mixed results when compared with laser or placebo. Steroids have been associated with increased incidence of cataracts and intraocular pressure rise but require fewer injections, especially when steroid implants are used.

LIMITATIONS

The quality of included studies varied considerably. Five of 14 meta-analyses had moderate or high statistical heterogeneity.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

The anti-VEGFs ranibizumab and bevacizumab have consistently shown good clinical effectiveness without major unwanted side effects. Steroid results have been mixed and are usually associated with cataract formation and  intraocular pressure increase. Despite the current wider spectrum of treatments for DMO, only a small proportion of patients recover good vision (≥20/40), and thus the search for new therapies needs to continue.

Triamcinolone and bevacizumab as adjunctive therapies to panretinal photocoagulation for proliferative diabetic retinopathy

Purpose. To evaluate efficacy of intravitreal triamcinolone (IVT) and bevacizumab (IVB) as adjunctive treatments to panretinal photocoagulation (PRP) in proliferative diabetic retinopathy (PDR). Methods. In 60 eyes of 45 patients with PDR, PRP (PRP group), PRP with IVT (IVT group), or PRP with IVB (IVB group) was performed. Regression of new vessels (NV), changes in best-corrected visual acuity (BCVA), central macular thickness (CMT), and contrast sensitivity at 1,2, and 6 months were evaluated. Results. Initial mean numbers of active NV and BCVA were 3.45 and 67.35 in the PRP group, 4.35 and 76.65 in the IVT group, and 4.79 and 75.53 in the IVB group. At the 6-month follow-up, numbers of active NV were 2.5 (P = 0.064), 1.11 (P = 0.000), and 1.11 (P = 0.002), and there was a mean loss of 2,6 (P = 0.055), 3.9 (P = 0.011), and 0.9 letters (P = 0.628) in the PRP, IVT, and IVB groups, respectively. Changes in CMT in the PRP and IVT groups were not significant, but significantly increased in the IVB group (P = 0.032). Contrast sensitivity remained stable in PRP and IVB groups and slightly decreased in IVT group. Conclusions. Adjunctive use of both triamcinolone and bevacizumab with PRP lead to a greater reduction of active NV than PRP alone in PDR, although no differences were seen between the two of them.

Preparation, characterization, and in vivo evaluation of triamcinolone acetonide microspheres after intravitreal administration

PURPOSE

The aim of this study was to evaluate the intraocular pressure (IOP) increasing effect and bioavailability of triamcinolone acetonide (TA) microspheres, as a novel drug delivery system, after intravitreal administration.

METHODS

Microspheres loaded by TA were prepared by the solvent evaporation method. After encapsulation, the final microspherical formulation was tested in an animal model. The left eyes of rabbits received microspherical TA and the right eyes were injected with conventional TA suspension. The drug concentration in the vitreous samples at days 7, 14, 28, and 56 after the injection was determined by high-performance liquid chromatography. The IOP was also checked at the same days with the Schiotz tonometer.

RESULTS

There was no statistically significant (P>0.05) difference between mean concentration of TA in the vitreous of right and left eyes at the different sampling times except day 56. Mean IOP of eyes that received microspherical TA was increased less than that of the eyes injected with TA suspension, and the difference was statistically significant (P<0.05) for each measurement day. TA was detectable in both eyes after 8 weeks. Both TA microsphere and suspension showed the sustained release profile.

CONCLUSION

The results of this study showed less IOP increasing effect of triamcinolone microspheres in comparison with suspension form.

Emerging drugs for diabetic retinopathy

INTRODUCTION

Diabetes mellitus with its ophthalmic complications is the major cause for legal blindness in industrialized countries. Diabetic macular edema and its complex pathophysiology as part of diabetic retinopathy are the leading cause of vision loss among diabetic patients. In recent years, treatment options have developed involving the intravitreal applications of several compounds.

AREAS COVERED

Current treatment options for diabetic macular edema including laser therapy and scientific basis of new drugs are discussed. Possible benefits and drawbacks of these new approaches are addressed.

EXPERT OPINION

In recent years, new drugs against retinal diseases have been developed consisting mainly of steroid or anti-vascular endothelial growth factor compounds. Targeting macular edema, the second shows a possible therapeutic role in the proliferative form of diabetic retinopathy, requiring further investigation. New biodegradable delivery systems show an advantage in sustaining effective compound concentrations for longer times and have positive impact on safety profile and cost-effectiveness of the drug, a factor of grave importance when considering the future of any new drug in the market. All these new therapeutic approaches alone or in combination with the existing treatments have to demonstrate their efficacy and safety in diabetic retinopathy in current and future trials.

Intravitreal triamcinolone acetonide versus combined intravitreal bevacizumab and dexamethasone in diffuse diabetic macular oedema

BACKGROUND

To compare the efficacy of a single injection of combined intravitreal dexamethasone and bevacizumab (Avastin) with that of intravitreal triamcinolone acetonide in eyes with diffuse cystoid diabetic macular oedema.

DESIGN

Prospective, non-randomized, masked, interventional case series.

PARTICIPANTS

Twenty-four eyes of 24 subjects with centre-involved diabetic macular oedema extending over two disc-areas with predominant cystic changes on spectral domain optical coherence tomography were selected.

METHODS

Ten phakic and two pseudophakic, ocular hypertensive eyes received intravitreal dexamethasone and bevacizumab as against 12 pseudophakic, normotensive eyes that received intravitreal triamcinolone acetonide.

MAIN OUTCOME MEASURES

Change in central macular volume on spectral domain optical coherence tomography and best-corrected visual acuity were measured at 6-week follow-up.

RESULTS

Baseline data were matched in both groups. Post-injection central macular volume (7.46 ± 0.73 mm(3)) was significantly lower (P < 0.001) in the intravitreal triamcinolone acetonide group when compared with its pre-injection central macular volume (9.11 ± 1.0 mm(3)) or when compared with the post-injection central macular volume (P = 0.02) of the intravitreal dexamethasone and bevacizumab group (8.42 ± 1.18 mm(3)). However, post-injection best-corrected visual acuity between the intravitreal triamcinolone acetonide (0.65 ± 0.15 logMAR) and the intravitreal dexamethasone and bevacizumab groups (0.685 ± 0.15 logMAR) was not significantly different (P = 0.06) at 6 weeks. No significant correlation was noted between change in central macular volume and change in best-corrected visual acuity (r = 0.35, P = 0.07) from the pooled data of both the groups. A fair correlation was noted between change in central macular volume and pre-injection central macular volume (r = 0.55, P = 0.005).

CONCLUSIONS

Intravitreal triamcinolone acetonide may be more effective than intravitreal dexamethasone and bevacizumab in reducing macular volume in patients with diffuse cystoid diabetic macular oedema. A significant reduction in macular volume does not necessarily translate into a correspondingly significant improvement in best-corrected visual acuity.

Intraocular and systemic pharmacokinetics of triamcinolone acetonide after a single 40-mg posterior subtenon application

PURPOSE

To characterize the pharmacokinetics of triamcinolone acetonide (TA) in aqueous, vitreous, and systemic circulation after a single subtenon injection.

DESIGN

Prospective interventional case series.

PARTICIPANTS

Thirty-six patients (36 eyes) who received a single posterior subtenon injection of TA (40 mg in 0.4 ml).

METHODS

Aqueous, vitreous, and blood samples were obtained at 1-hour, 1-day, 3-day, 5-day, 10-day, 14-day, 21-day, and 28-day time points after the posterior subtenon TA injection. At each time point, there were 3 to 6 eyes (patients). The concentrations of TA in the aqueous, vitreous, and plasma were analyzed using ultra-performance liquid chromatography coupled with tandem mass spectrometry.

MAIN OUTCOME MEASURES

Triamcinolone acetonide concentration in the samples was measured, and pharmacokinetic parameters were calculated.

RESULTS

The TA concentration-time profile in aqueous consisted of a fast distribution phase during the first 24 hours and a slow elimination phase thereafter. In contrast, the TA concentration-time profile in vitreous consisted of an absorption phase during the first 24 hours followed by a slow elimination phase. The TA in plasma followed a mono-exponential elimination during the study course. The TA concentration peak time for aqueous and plasma was at 1 hour and 24 hours, for vitreous after subtenon injection. The terminal elimination half-life in aqueous, vitreous, and plasma was 11.8, 17.1, and 25 days, respectively. The integral of the area under the concentration time curve (AUC(0-∞)) was 862 ng/day/ml for aqueous, 1262 ng/day/ml for vitreous, and 17.4 ng/day/ml for plasma. The total TA exposure to vitreous was 46% more than total TA exposure to the aqueous. The TA concentration in vitreous was 70- to 98-fold higher than that in plasma.

CONCLUSIONS

Posterior subtenon TA application can provide a sustained high local ocular TA level while also resulting in a very low systemic TA level, which may be well below the normal glucocorticoid level in humans.

The in vitro response of human retinal endothelial cells to cytokines and other chemically active agents is altered by coculture with vitreous-derived hyalocytes

BACKGROUND

Ocular angiogenesis is regulated by polypeptides including cytokines, which are known to affect vascular endothelial cells. We have reported that hyalocytes interact with vascular endothelial cells, and some cytokines affect these interactions.

AIMS

To determine the effect of various chemically active agents on the viability of endothelial cells alone and cocultured with hyalocytes.

METHODS

The viability of human retinal endothelial cells (HRECs) was determined after exposure to IL-1alpha, IL-1beta, IL-6, TNFalpha and VEGF using the MTT assay. These results were compared to the viability when the HRECs were cocultured with porcine hyalocytes that had been exposed to different types of cytokines. The effects of bevacizumab, fenofibrate and dexamethasone on the viability of HRECs in coculture with hyalocytes were also assessed.

RESULTS

Ten micrograms/millilitre of bevacizumab decreased the percentage of living HRECs stimulated by VEGF without hyalocytes, but with the hyalocytes, 100 microg/ml of bevacizumab was required to decrease the percentage of viable HRECs stimulated by VEGF. Fenofibrate, at 5 microg/ml, decreased the viability of HRECs stimulated by IL-1beta and VEGF without hyalocytes but could not decrease the viability of HRECs cocultured with hyalocytes. Dexamethasone, at 50 microg/ml, decreased the viability of HRECs stimulated by IL-1alpha, IL-1beta, IL-6 and VEGF without hyalocytes but could not decrease the viability of HRECs cocultured.

CONCLUSIONS

Coculturing HRECs with vitreous-derived hyalocytes depressed the effects of cytokines, bevacizumab, fenofibrate and dexamethasone. This suggests that the vitreal hyalocytes may play a role in pathogenic endothelial cell proliferation in vivo. Future studies to better understand this pathobiology should utilize coculture systems of HRECs and vitreal hyalocytes.

A randomized trial comparing the efficacy and safety of intravitreal triamcinolone with standard care to treat vision loss associated with macular Edema secondary to branch retinal vein occlusion: the Standard Care vs Corticosteroid for Retinal Vein Occlusion (SCORE) study report 6

OBJECTIVE

To compare the efficacy and safety of 1-mg and 4-mg doses of preservative-free intravitreal triamcinolone with standard care (grid photocoagulation in eyes without dense macular hemorrhage and deferral of photocoagulation until hemorrhage clears in eyes with dense macular hemorrhage) for eyes with vision loss associated with macular edema secondary to branch retinal vein occlusion (BRVO).

METHODS

Multicenter, randomized clinical trial of 411 participants. Main Outcome Measure Gain in visual acuity letter score of 15 or more from baseline to month 12.

RESULTS

Twenty-nine percent, 26%, and 27% of participants achieved the primary outcome in the standard care, 1-mg, and 4-mg groups, respectively. None of the pairwise comparisons between the 3 groups was statistically significant at month 12. The rates of elevated intraocular pressure and cataract were similar for the standard care and 1-mg groups, but higher in the 4-mg group.

CONCLUSIONS

There was no difference identified in visual acuity at 12 months for the standard care group compared with the triamcinolone groups; however, rates of adverse events (particularly elevated intraocular pressure and cataract) were highest in the 4-mg group. Application to Clinical Practice Grid photocoagulation as applied in the SCORE Study remains the standard care for patients with vision loss associated with macular edema secondary to BRVO who have characteristics similar to participants in the SCORE-BRVO trial. Grid photocoagulation should remain the benchmark against which other treatments are compared in clinical trials for eyes with vision loss associated with macular edema secondary to BRVO. Trial Registration clinicaltrials.gov Identifier: NCT00105027.

A randomized trial comparing the efficacy and safety of intravitreal triamcinolone with observation to treat vision loss associated with macular edema secondary to central retinal vein occlusion: the Standard Care vs Corticosteroid for Retinal Vein Occlusion (SCORE) study report 5

OBJECTIVE

To compare the efficacy and safety of 1-mg and 4-mg doses of preservative-free intravitreal triamcinolone with observation for eyes with vision loss associated with macular edema secondary to perfused central retinal vein occlusion (CRVO).

METHODS

Multicenter, randomized, clinical trial of 271 participants.

MAIN OUTCOME MEASURE

Gain in visual acuity letter score of 15 or more from baseline to month 12.

RESULTS

Seven percent, 27%, and 26% of participants achieved the primary outcome in the observation, 1-mg, and 4-mg groups, respectively. The odds of achieving the primary outcome were 5.0 times greater in the 1-mg group than the observation group (odds ratio [OR], 5.0; 95% confidence interval [CI], 1.8-14.1; P = .001) and 5.0 times greater in 4-mg group than the observation group (OR, 5.0; 95% CI, 1.8-14.4; P = .001); there was no difference identified between the 1-mg and 4-mg groups (OR, 1.0; 95% CI, 0.5-2.1; P = .97). The rates of elevated intraocular pressure and cataract were similar for the observation and 1-mg groups, but higher in the 4-mg group.

CONCLUSIONS

Intravitreal triamcinolone is superior to observation for treating vision loss associated with macular edema secondary to CRVO in patients who have characteristics similar to those in the SCORE-CRVO trial. The 1-mg dose has a safety profile superior to that of the 4-mg dose. Application to Clinical Practice Intravitreal triamcinolone in a 1-mg dose, following the retreatment criteria applied in the SCORE Study, should be considered for up to 1 year, and possibly 2 years, for patients with characteristics similar to those in the SCORE-CRVO trial. Trial Registration clinicaltrials.gov Identifier: NCT00105027.

Pharmacotherapy for diabetic retinopathy

BACKGROUND

Diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR) continue to cause significant visual loss among patients with diabetes mellitus. In some patients unresponsive to standard laser techniques, as well as improved control of blood pressure and blood sugar, pharmacologic treatment may be beneficial. Although no agent is now approved by the FDA for this purpose, many agents are now being studied in randomized clinical trials (RCTs).

OBJECTIVE

To review concisely the chief pharmacotherapies for diabetic retinopathy available at present.

METHODS

Literature review and synopsis.

RESULTS

Used alone, intravitreal triamcinolone acetonide (IVTA) seems to have some short-term efficacy against DME, but longer-term outcomes (< or = 3 years) using IVTA monotherapy showed a lesser benefit than focal/grid laser treatment in a prospective RCT done by the Diabetic Retinopathy Clinical Research Network. Intravitreal anti-VEGF agents have demonstrated some short-term efficacy against DME, and continuing RCTs will evaluate combination therapies (anti-VEGF and laser) for both DME and PDR. Other agents are being evaluated in pilot studies and Phase II RCTs.

CONCLUSION

Pharmacotherapies for DME and PDR have potential for vision stabilization or improvement. Continuing RCTs will provide evidence-based data on their role in clinical practice. A potential role for pharmacotherapy in the prevention of DME and PDR is also emerging.

Triamcinolone acetonide preparations: impact of crystal size on in vitro behavior

PURPOSE

To characterize the in vitro behavior of three preparations of triamcinolone acetonide (TA).

METHODS

Three preparations of TA were mixed with Balanced Salt Solution Plus: commercially available TA (Kenalog 40, Bristol-Myers Squibb, Princeton, NJ), compounded preservative-free triamcinolone acetonide (PFTA, New England Compounding Center, Framingham, MA), and triamcinolone acetonide injectable suspension (TAIS, TRIESENCE, Alcon, Inc., Fort Worth, TX). We determined the mean number of crystalline aggregates per high-power deconvolution microscopy field, largest aggregate area, and spectroscopic photometric absorption.

RESULTS

Preservative-free triamcinolone acetonide had larger mean number of aggregates compared with TA (time 0 P = 0.002, 10 minutes P < 0.001) and TAIS (time 0 P < 0.001, 10 minutes P = 0.003). Aggregate size varied at both 0 and 10 minutes: TAIS > TA > PFTA. Spectroscopic photometric absorption decreased in direct correlation to aggregate size over time for all three preparations.

CONCLUSION

In vitro, PFTA in Balanced Salt Solution Plus had more aggregates of smaller size than either TA or TAIS. By contrast, TAIS had much larger aggregate size than both PFTA and TA, and this increased over time. These findings correlate with the clinical observations that PFTA and TA tend to disperse throughout the vitreous, whereas TAIS tends to conglomerate and gravitate toward the most dependent portion of the eye in a globular fashion.

Optical coherence tomographic hyperreflective foci: a morphologic sign of lipid extravasation in diabetic macular edema

PURPOSE

To analyze hyperreflective foci typically seen in diabetic macular edema (DME) in optical coherence tomography (OCT).

DESIGN

Prospective clinical trial.

PARTICIPANTS

Twelve consecutive patients with treatment-naïve, clinically significant DME.

METHODS

During a same-day examination, a standardized visual acuity assessment (Early Treatment of Diabetic Retinopathy Study protocol), infrared fundus imaging, color fundus photography, and biomicroscopy were performed. Additionally, all patients were scanned using Stratus, Cirrus, and Spectralis OCT and results correlated.

MAIN OUTCOME MEASURES

Morphologic changes secondary to DME.

RESULTS

In all eyes with DME, distinct hyperreflective foci distributed throughout all retinal layers were found in the OCT scans of all 3 OCT devices. These deposits could not be identified by infrared imaging, fundus photography, or biomicroscopy as long as they were not confluent. Accumulations of such foci at the border of the outer nuclear and in the outer plexiform layer were recognizable clinically as hard exudates showing the same hyperreflective features in OCT. The hyperreflectivity of these foci did not correspond with intraretinal hemorrhage, nor did the lesions cause the characteristic OCT laser beam scattering phenomena typically seen secondary to intraretinal bleedings or microaneurysms. Further, they were detected within the walls of intraretinal microaneurysms.

CONCLUSIONS

Well-demarcated, hyperreflective foci were identified in the retina of patients with DME. The deposits were located within walls of intraretinal microaneurysms and scattered throughout all retinal layers, forming confluent plaques in the outer plexiform layer. It is suggested that the foci represent extravasated lipoproteins and/or proteins being a very early subclinical barrier breakdown sign in DME.

Steroids do not prevent photoreceptor degeneration in the light-exposed T4R rhodopsin mutant dog retina irrespective of AP-1 inhibition

PURPOSE

AP-1 has been proposed as a key intermediate linking exposure to light and photoreceptor cell death in rodent light-damage models. Inhibition of AP-1 associated with steroid administration also prevents light damage. In this study the role of steroids in inhibiting AP-1 activation and/or in preventing photoreceptor degeneration was examined in the rhodopsin mutant dog model.

METHODS

The dogs were dark adapted overnight, eyes dilated with mydriatics; the right eye was light occluded and the fundus of the left eye photographed ( approximately 15-17 overlapping frames) with a fundus camera. For biochemical studies, the dogs remained in the dark for 1 to 3 hours after exposure. Twenty-four hours before exposure to light, some dogs were treated with systemic dexamethasone or intravitreal/subconjunctival triamcinolone. AP-1 DNA-binding activity was determined by electrophoresis mobility shift assay (EMSA) and phosphorylation of c-Fos and activation of ERK1/2 were determined by immunoblot analyses. The eyes were collected 1 hour and 2 weeks after exposure to light, for histopathology and immunocytochemistry.

RESULTS

Inhibition of AP-1 activation, and phosphorylation of ERK1/2 and c-Fos were found after dexamethasone treatment in light-exposed T4R RHO mutant dog retinas. In contrast, increased AP-1 activity and phosphorylation of c-Fos and ERK1/2 were found in triamcinolone-treated mutant retinas. Similar extensive rod degeneration was found after exposure to light with or without treatment, and areas with surviving photoreceptor nuclei consisted primarily of cones. Only with systemic dexamethasone did the RPE cell layer remain.

CONCLUSIONS

Intraocular or systemic steroids fail to prevent light-induced photoreceptor degeneration in the T4R RHO dog retina. Finding that systemic dexamethasone prevents AP-1 activation, yet does not prevent retinal light damage, further supports the hypothesis that AP-1 is not the critical player in the cell-death signal that occurs in rods.

Novel Pharmacologic Approaches for the Management of Diabetic Retinopathy

Diabetic retinopathy is the leading cause of vision loss among working-age people in the United States. The hallmark of diabetic retinopathy is vascular compromise. Increased vascular permeability leads to the development of diabetic macular edema, which is the major cause of vision loss in patients with diabetic retinopathy. Vascular occlusion causes retinal ischemia and subsequent angiogenesis (proliferative diabetic retinopathy), which increases the risk for vitreous hemorrhage and retinal detachment. Over the past 30 years our understanding of the pathophysiology of diabetic retinopathy has evolved greatly and has fostered the development of many novel treatments for this condition. This article will review promising new local and systemic pharmacologic treatments for diabetic macular edema and proliferative diabetic retinopathy.