Intravitreal triamcinolone as an adjunct in the treatment of concomitant proliferative diabetic retinopathy and diffuse diabetic macular oedema

OMICs approaches-assisted identification of macrophages-derived MIP-1γ as the therapeutic target of botanical products TNTL in diabetic retinopathy

BACKGROUND

Inflammatory reaction in the dysfunction of retinal endotheliocytes has been considered to play a vital role in diabetic retinopathy (DR). Anti-inflammatory therapy so far gains poor outcome as DR treatment. This study aims to identify a novel therapeutic target of DR from the OMICs studies of a traditional anti-DR botanical products TNTL.

METHODS

Hyperglycemic mice were treated with TNTL. The anti-hyperglycemic effect of TNTL was validated to confirm the biological consistency of the herbal products from batches. Improvement of DR by TNTL was examined by various assays on the retina. Next-generation transcriptome sequencing and cytokine array was used to identify the therapeutic targets. In vitro study was performed to validate the target.

RESULTS

We observed that TNTL at its high doses possessed anti-hyperglycemic effect in murine type I diabetic model, while at its doses without reducing blood glucose, it suppressed DR incidence. TNTL restored the blood-retina barrier integrity, suppressed retinal neovascularization, and attenuated the retinal ganglion cell degeneration. Transcriptomic analysis on the retina tissue of hyperglycemic mice with or without TNTL revealed that the inflammatory retina microenvironment was significantly repressed. TNTL treatment suppressed pro-inflammatory macrophages in the retina, which resulted in the inactivation of endothelial cell migration, restoration of endothelial cell monolayer integrity, and prevention of leakage. Cytokine array analysis suggested that TNTL could significantly inhibit the secretion of MIP1γ from pro-inflammatory macrophages. Prevention of endothelial dysfunction by TNTL may be mediated by the inhibition of MIP1γ/CCR1 axis. More specifically, TNTL suppressed MIP1γ release from pro-inflammatory macrophages, which in turn inhibited the activation of CCR1-associated signaling pathways in endothelial cells.

CONCLUSION

Our findings demonstrated that TNTL might be an alternative treatment to DR, and the primary source of potential drug candidates against DR targeting MIP1γ/CCR1 axis in the retinal microenvironment.

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.

Current and future approaches in the prevention and treatment of diabetic retinopathy

Diabetic retinopathy (DR) is a major cause of blindness worldwide and is the number one cause of blindness in working-age individuals in developed countries. We review the current literature and discuss the pathogenesis, modifying risk factors, genetics, and treatment of DR. Special focus is placed on the rationale and effectiveness of therapeutic modalities, both current and future.

Efficacy of intravitreal triamcinolone after or concomitant with laser photocoagulation in nonproliferative diabetic retinopathy with macular edema

PURPOSE

To investigate the clinical effects and outcomes of intravitreal injection of 4 mg of triamcinolone acetonide (IVTA) after or concomitant with macular laser photocoagulation (MP) for clinically significant macular edema (CSME).

METHODS

Forty-nine eyes of 49 patients with nonproliferative diabetic retinopathy and CSME were randomized into three groups. The eyes in the laser group (n=17), group 1, were subjected to MP 3 weeks after IVTA; the eyes in the IVTA group (n=13), group 2, were subjected to MP, concomitant with IVTA; the eyes in the control group (n=19), group 3, underwent only IVTA application. Visual acuity (VA), fundus fluorescein angiography, and photography were performed in each group.

RESULTS

In the first group, the mean VA improved from 0.17-/+0.09 at baseline to 0.28-/+0.15 (p=0.114) and in the second group, deteriorated from 0.19-/+0.08 at baseline to 0.14-/+0.08 at the sixth month (p=0.141), respectively. In Group 3, the mean VA improved from 0.16-/+0.08 at baseline to 0.28-/+0.18 (p=0.118) at the end of the follow-up. When VA was compared between the control and study groups, significant difference was detected at the sixth month (p=0.038).

CONCLUSIONS

MP after IVTA improved VA, rather than MP concomitant with IVTA, and only IVTA application for CSME. MP after IVTA may reduce the recurrence of CSME and needs further investigations in a longer period.

Combined laser and intravitreal triamcinolone for proliferative diabetic retinopathy and macular edema: one-year results of a randomized clinical trial

PURPOSE

To evaluate laser combined with intravitreal triamcinolone acetonide (IVTA) for the management of patients with proliferative diabetic retinopathy (PDR) and clinically significant macular edema (CSME).

DESIGN

Randomized clinical trial.

METHODS

settings: Single center. study population: Twenty-two patients with bilateral treatment-naïve moderate PDR and CSME. intervention: Laser (panretinal and macular) photocoagulation was performed in each eye, followed by IVTA in one randomly assigned eye. Best-corrected visual acuity (BCVA), fundus photography, and optical coherence tomography were performed at baseline and at months 1, 3, 6, 9, and 12. main outcome measures: Changes in BCVA, central macular thickness (CMT), and total macular volume (TMV).

RESULTS

The mean logarithm of the minimal angle of resolution (logMAR) BCVA improved significantly, and mean CMT and TMV were significantly reduced in the IVTA group compared with the laser-only group (controls) at all study follow-up visits (P < .001). The mean logMAR BCVA (Snellen equivalent) was 0.44 (20/50(-2)) for the IVTA group and 0.38 (20/50(+1)) for the controls at baseline, and 0.12 (20/25(-1)) for the IVTA group and 0.32 (20/40(-1)) for the controls at 12 months (P < .001). The mean CMT and TMV were, respectively, 360 microm and 8.59 mm(3) for the IVTA group and 331 microm and 8.44 mm(3) for the controls at baseline, and 236 microm and 7.32 mm(3) for the IVTA group and 266 microm and 7.78 mm(3) for the controls at 12 months (P < .001).

CONCLUSIONS

The combination of laser photocoagulation with IVTA was associated with improved BCVA and decreased CMT and TMV when compared with laser photocoagulation alone for the treatment of moderate PDR with CSME.

Intravitreal bevacizumab versus combined bevacizumab-triamcinolone versus macular laser photocoagulation in diabetic macular edema

PURPOSE

To evaluate the additive effect of triamcinolone to bevacizumab in comparison to standard macular laser photocoagulation versus bevacizumab in the management of diabetic macular edema (DME).

METHODS

In a prospective, randomized clinical trial, 130 eyes of 110 patients with type 2 diabetes with DME were included. Eligible eyes were randomly assigned to 1.25 mg intravitreal bevacizumab (42 eyes) (IVB group) or combination of 1.25 mg bevacizumab and 2 mg triamcinolone acetonide (41 eyes) (IVB+IVT group) or macular laser photocoagulation (47 eyes) (MPC). Central macular thickness (CMT) and visual acuity changes at week 6 and 16 were assessed.

RESULTS

The mean age of the patients was 57 -/+7 years. Patients were followed 16 weeks. At week 6, all the three groups showed significant reduction in CMT but the reductions for IVB and IVB+IVT were significantly more than MPC (p<0.001). At week 16, the response was not stable for IVB (p<0.001), but IVB+IVT maintained its superior status to MPC (p<0.001). At week 16, visual acuities were essentially unchanged for the two groups of MPC and IVB and improvement for IVB+IVT was marginal and at most was 0.1 log MAR. No patient developed uveitis, endophthalmitis, or thromboembolic event.

CONCLUSIONS

Single intravitreal bevacizumab or triamcinolone plus bevacizumab injection brought about significantly greater macular thickness reduction in diabetic patients in comparison to standard laser treatment. However, the response for bevacizumab alone was short-lived. Reduction in macular thickness was only marginally associated with visual acuity improvement in the triamcinolone plus bevacizumab injection group.

Targeting the retinal microcirculation to treat diabetic sight problems

Diabetic retinopathy is a secondary complication of hyperglycemia caused by diabetes mellitus. The damage to the retina can ultimately cause vision loss as a result of increased capillary permeability and angiogenesis. Recent progress in the understanding of the mediators that drive angiogenesis, as well as the phenotypes of cells that are involved in this process, has provided a multitude of targets for pharmacologic intervention. This review presents the inhibitors of the biochemical processes that are at the root of diabetic retinopathy (i.e., non-enzymatic glycosylation of biomolecules, oxidative stress, activation of aldose reductase and activation of protein kinase C by formation of diacylglycerol) in addition to the inhibitors of the mechanical damage (i.e., increased vascular permeability, capillary occlusion and neovascularization).

The relationship of macular thickness to clinically graded diabetic retinopathy severity in eyes without clinically detected diabetic macular edema

PURPOSE

To examine the relationship of optical coherence tomography (OCT) measured macular thickness to retinopathy severity in patients with diabetes and no clinically detectable macular edema.

DESIGN

Retrospective observational case series.

PARTICIPANTS

Three hundred eighty-three eyes of 383 patients of a private retina practice; including 100 normal eyes of patients without diabetes, 100 eyes of diabetics without retinopathy, 100 eyes of diabetics with mild to moderate retinopathy, 35 eyes of diabetics with severe nonproliferative or proliferative retinopathy, and 48 eyes of diabetics with regressed proliferative retinopathy.

METHODS

Review of clinical charts and optical coherence tomography measurements.

MAIN OUTCOME MEASURES

Central subfield mean thickness (CSMT), inner and outer zone measurements, and total macular volume.

RESULTS

Central subfield mean thicknesses (mean +/- standard deviation) were 208+/-22, 198+/-25, 204+/-26, 224+/-38, and 205+/-27 microm for normals, eyes of diabetics without retinopathy, eyes with mild to moderate nonproliferative retinopathy, eyes with severe nonproliferative to proliferative retinopathy, and eyes with regressed proliferative retinopathy, respectively. For all groups, mean CSMT was larger in males than in females. Statistically significant differences by gender were observed for normals, diabetics without retinopathy, and diabetics with mild to moderate nonproliferative retinopathy (mean differences, 12, 14, and 18 microm, respectively; Ps = 0.0057, 0.0057, and 0.0002). For increasing retinopathy severity, the probability of macular thickening detected by OCT but not detected by clinical examination increased. Fifteen percent of eyes with severe nonproliferative or proliferative retinopathy and no clinically detected edema had OCT-measured macular thickening.

CONCLUSIONS

Because OCT measurements are gender dependent, gender balance or statistical adjustment for gender imbalances of compared groups in OCT studies of diabetic macular edema is important. As retinopathy severity increases, the probability of subclinical edema rises. Except for an individual baseline measurement possibly useful for longitudinal comparison, the data suggest that there is little reason routinely to obtain OCT in eyes with diabetes and no retinopathy or mild to moderate diabetic retinopathy when clinical examination fails to show macular edema.