Efficacy and vitreous levels of topical NSAIDs

What else can we do to prevent diabetic retinopathy?

The classical modifiable factors associated with the onset and progression of diabetic retinopathy are the suboptimal control of blood glucose levels and hypertension, as well as dyslipidaemia. However, there are other less recognised modifiable factors that can play a relevant role, such as the presence of obesity or the abnormal distribution of adipose tissue, and others related to lifestyle such as the type of diet, vitamin intake, exercise, smoking and sunlight exposure. In this article we revisit the prevention of diabetic retinopathy based on modulating the modifiable risk factors, as well as commenting on the potential impact of glucose-lowering drugs on the condition. The emerging concept that neurodegeneration is an early event in the development of diabetic retinopathy points to neuroprotection as a potential therapeutic strategy to prevent the advanced stages of the disease. In this regard, the better phenotyping of very early stages of diabetic retinopathy and the opportunity of arresting its progression using treatments targeting the neurovascular unit (NVU) are discussed.

Comparison of the Effect of Bromfenac versus Betamethasone Ophthalmic Solutions in Patients with Diabetic Macular Edema

PURPOSE

To examine the effect of 0.1% bromfenac (BF) ophthalmic solution and 0.1% betamethasone (BM) ophthalmic solution on diabetic macular edema (DME).

METHODS

This was a prospective trial. Nineteen patients (mean age of 66.6 ± 10.1 years) with DME and mean retinal thickness within a diameter of 1 mm from the fovea (central subfield thickness: CST) of 250-500 µm were randomized and instilled with BF or BM. CST, best-corrected visual acuity (BCVA), and intraocular pressure (IOP) were measured at 4, 8, and 12 weeks after administration.

RESULTS

CST at baseline (p = .128) and that at 4, 8, and 12 weeks of administration was not significantly different between the BF (10 patients) and BM groups (9 patients). In patients with glycated hemoglobin (HbA1c) <8.0%, CST, compared with baseline, was significantly decreased in the BF group (seven patients) at 8 (p = .025) and 12 weeks (p = .043) of administration. When compared with the baseline, no significant changes in BCVA were observed at any point in time in either group. Baseline IOP was comparable between the groups. In the BM group, the values of change in IOP from baseline significantly increased at 8 (p = .025) and 12 weeks (p = .044) of administration, with no significant changes in IOP over the 12 weeks of administration in the BF group.

CONCLUSIONS

BF did not affect IOP even after 12 weeks of administration, suggesting its effect in reducing CST in DME with good glycemic control.

TRIAL REGISTRATION

University Hospital Medical Information Network (UMIN-CTR); UMIN000026201, February 18, 2017; Japan Registry of Clinical Trials; jRCTs031180308, March 15, 2019.

Metallic Engineered Nanomaterials and Ocular Toxicity: A Current Perspective

The ocular surface, comprised of the transparent cornea, conjunctiva, and protective tear film, forms a protective barrier defending deeper structures of the eye from particulate matter and mechanical trauma. This barrier is routinely exposed to a multitude of naturally occurring and engineered nanomaterials (ENM). Metallic ENMs are particularly ubiquitous in commercial products with a high risk of ocular exposure, such as cosmetics and sunscreens. Additionally, there are several therapeutic uses for metallic ENMs owing to their attractive magnetic, antimicrobial, and functionalization properties. The increasing commercial and therapeutic applications of metallic ENMs come with a high risk of ocular exposure with poorly understood consequences to the health of the eye. While the toxicity of metallic ENMs exposure has been rigorously studied in other tissues and organs, further studies are necessary to understand the potential for adverse effects and inform product usage for individuals whose ocular health may be compromised by injury, disease, or surgical intervention. This review provides an update of current literature on the ocular toxicity of metallic ENMs in vitro and in vivo, as well as the risks and benefits of therapeutic applications of metallic ENMs in ophthalmology.

Neurovascular Unit: A New Target for Treating Early Stages of Diabetic Retinopathy

The concept of diabetic retinopathy as a microvascular disease has evolved and is now considered a more complex diabetic complication in which neurovascular unit impairment plays an essential role and, therefore, can be considered as a main therapeutic target in the early stages of the disease. However, neurodegeneration is not always the apparent primary event in the natural story of diabetic retinopathy, and a phenotyping characterization is recommendable to identify those patients in whom neuroprotective treatment might be of benefit. In recent years, a myriad of treatments based on neuroprotection have been tested in experimental models, but more interestingly, there are drugs with a dual activity (neuroprotective and vasculotropic). In this review, the recent evidence concerning the therapeutic approaches targeting neurovascular unit impairment will be presented, along with a critical review of the scientific gaps and problems which remain to be overcome before our knowledge can be transferred to clinical practice.

Nonsteroidal anti-inflammatory drugs for retinal neurodegenerative diseases

Nonsteroidal anti-inflammatory drugs (NSAIDs) are among the most common prescription drugs for inflammation, and topical NSAIDs are often used in ophthalmology to reduce pain, photophobia, inflammation, and edema. In recent years, many published reports have found that NSAIDs play an important role in the treatment of retinal neurodegenerative diseases, such as age-related macular degeneration (AMD), diabetic retinopathy (DR), glaucoma, pathological myopia, and retinitis pigmentosa (RP). The aim of the current review is to provide an overview of the role of various NSAIDs in the treatment of retinal neurodegenerative diseases and the corresponding mechanisms of action. This review highlighted that the topical application of NSAIDs for the treatment of retinal degenerative diseases has been studied to a remarkable extent and that its beneficial effects in many diseases have been proven. In the future, prospective studies with large study populations are required to extend these effects to clinical settings.

Diabetes and diabetic retinopathy in patients undergoing cataract surgery: a prevalence study-DiCat study report #2

PURPOSE

To report on the prevalence of diabetes, diabetic macula oedema (DME) and retinopathy and their respective grading in a large cohort of patients undergoing cataract surgery.

METHODS

Data on previous diagnosis of diabetes, fasting glucose, glycated haemoglobin, presence and type of retinopathy and other maculopathy of 3657 patients over 55 years of age undergoing cataract surgery in 13 centres scattered throughout Italy were analysed.

RESULTS

A total of 20.4% of patients were known diabetics and 27.9% of diabetics showed signs of retinopathy. Haemoglobin A1C was higher than 48 mmol/L (6.5%) in 32% of diabetics and 2.4% non-diabetics. Fasting blood glucose level was higher than 120 mg/dL in 4.3% non-diabetics and 50% diabetics. Duration of diabetes did not significantly correlate with either fasting glucose or glycated haemoglobin, while higher grades of diabetic retinopathy were significantly more prevalent as duration of disease increased. DME was present in almost 40% of diabetics and 22% of patients showed non-diabetic maculopathy.

DISCUSSION

Diabetic retinopathy and DME worsen after cataract extraction thus complicating long-term prognosis and requiring expensive injective therapy. Since unknown diabetics represent 2-4% of the many million cataract candidates and even known diabetics show poor metabolic control and high rates of DME, preoperative medical testing and accurate retinopathy screening may prove both ethically necessary and cost-effective.

Adjuvant Therapies in Diabetic Retinopathy as an Early Approach to Delay Its Progression: The Importance of Oxidative Stress and Inflammation

Diabetes mellitus (DM) is a progressive disease induced by a sustained state of chronic hyperglycemia that can lead to several complications targeting highly metabolic cells. Diabetic retinopathy (DR) is a multifactorial microvascular complication of DM, with high prevalence, which can ultimately lead to visual impairment. The genesis of DR involves a complex variety of pathways such as oxidative stress, inflammation, apoptosis, neurodegeneration, angiogenesis, lipid peroxidation, and endoplasmic reticulum (ER) stress, each possessing potential therapeutic biomarkers. A specific treatment has yet to be developed for early stages of DR since no management is given other than glycemic control until the proliferative stage develops, offering a poor visual prognosis to the patient. In this narrative review article, we evaluate different dietary regimens, such as the Mediterranean diet, Dietary Pattern to Stop Hypertension (DASH) and their functional foods, and low-calorie diets (LCDs). Nutraceuticals have also been assessed in DR on account of their antioxidant, anti-inflammatory, and antiangiogenic properties, which may have an important impact on the physiopathology of DR. These nutraceuticals have shown to lower reactive oxygen species (ROS), important inflammatory factors, cytokines, and endothelial damage biomarkers either as monotherapies or combined therapies or concomitantly with established diabetes management or nonconventional adjuvant drugs like topical nonsteroidal anti-inflammatory drugs (NSAIDs).

Fabrication of conductive fibrous scaffold for photoreceptor differentiation of mesenchymal stem cell

Conductive nanofibrous scaffolds with that can conduct electrical current have a great potential in neural tissue engineering. The purpose of this study was to survey effects of electrical stimulation and polycaprolactone/polypyrrole/multiwall carbon nanotube (PCL/PPY/MWCNTs) fibrous scaffold on photoreceptor differentiation of trabecular meshwork mesenchymal stem cells (TM-MSCs). PCL/PPY/MWCNTs scaffold was made by electrospinning method. TM-MSCs were seeded on PCL/PPY/MWCNTs scaffold and stimulated with a potential of 115 V/m. Scanning electron microscopy, transmission electron microscopy, and FT-IR were used to evaluate the fabricated scaffold. Immunofluorescence and quantitative real-time polymerase chain reaction were used to examine differentiated cells. Scanning electron microscopy, transmitting electron microscopy, and FT-IR confirmed the creation of the composite structure of fibers. RT-qPCR analysis showed that the expression of rhodopsin and peripherin genes in electrically stimulated cells were significantly higher (5.7- and 6.23-fold, respectively; p ≤ 0.05) than those with no electrical stimulation. Collectively, it seems that the combination of PCL/PPY/MWCNTs scaffold, as a suitable conductive scaffold, and electrical stimulation could be an effective approach in the differentiation of stem cells in retinal tissue engineering.

SOCS1-Derived Peptide Administered by Eye Drops Prevents Retinal Neuroinflammation and Vascular Leakage in Experimental Diabetes

Current treatments for diabetic retinopathy (DR) target late stages when vision has already been significantly affected. Accumulating evidence suggests that neuroinflammation plays a major role in the pathogenesis of DR, resulting in the disruption of the blood-retinal barrier. Suppressors of cytokine signaling (SOCS) are cytokine-inducible proteins that function as a negative feedback loop regulating cytokine responses. On this basis, the aim of the present study was to evaluate the effect of a SOCS1-derived peptide administered by eye drops (2 weeks) on retinal neuroinflammation and early microvascular abnormalities in a db/db mouse model. In brief, we found that SOCS1-derived peptide significantly reduced glial activation and neural apoptosis induced by diabetes, as well as retinal levels of proinflammatory cytokines. Moreover, a significant improvement of electroretinogram parameters was observed, thus revealing a clear impact of the histological findings on global retinal function. Finally, SOCS1-derived peptide prevented the disruption of the blood-retinal barrier. Overall, our results suggest that topical administration of SOCS1-derived peptide is effective in preventing retinal neuroinflammation and early microvascular impairment. These findings could open up a new strategy for the treatment of early stages of DR.

Comparative assessment of intraocular inflammation following standard or heavy silicone oil tamponade: a prospective study

PURPOSE

To evaluate the inflammation associated with the use of standard silicone oil (polydimethylsiloxane; PDMS) and heavy silicone oil (HSO) Densiron-68™ in patients undergoing vitrectomy for retinal detachment.

MATERIALS AND METHODS

A prospective study was performed involving 35 patients scheduled to undergo vitrectomy for retinal detachment. Patients received PDMS or Densiron-68™ HSO according to superior or inferior retinal localization of the tears, respectively. For assessing the inflammation, prostaglandin E2 (PGE₂ ) and interleukin-1α (IL-1α) levels were evaluated in the aqueous.

RESULTS

Thirty-five eyes of 35 patients completed the study: 20 eyes received HSO, and 15 eyes received PDMS. The mean aqueous PGE₂ level was significantly higher in HSO patients than in PDMS patients (869.16 ± 242.83 pg/ml versus 369.38 ± 209.7 pg/ml, respectively; p < 0.0001). The mean aqueous IL-1α level was also significantly higher in HSO patients than in PDMS patients (81.40 ± 36.9 pg/ml versus 40.8 ± 32.5 pg/ml, respectively; p = 0.002). In HSO, a moderate positive correlation between the endotamponade duration and both PGE₂ (r = 0.44; p = 0.05) and IL-1α (r = 0.48; p = 0.033) levels was observed. In PDMS, a strong positive correlation between the endotamponade duration and both PGE₂ (r = 0.89; p < 0.0001) and IL-1α (r = 0.68; p = 0.006) levels was observed.

CONCLUSION

Although both HSO and PDMS yielded favourable success rates in the surgical treatment of complicated retinal detachments, HSO triggered a more severe inflammatory reaction, in a time-dependent manner.

Comparative study of the efficacy and safety of bromfenac, nepafenac and diclofenac sodium for the prevention of cystoid macular edema after phacoemulsification

AIM

To compare the efficacy, tolerability and safety of bromfenac 0.09%, nepafenac 0.1% or diclofenac 0.1% for the prophylaxis of the cystoid macular edema (CME) after phacoemulsification.

METHODS

Group sequential observational comparative study. After phacoemulsification, patients received two months for topical treatment of either diclofenac sodium, bromfenac or nepafenac. All patients received concomitant topical tobramycin 0.3% and topical prednisolone 1%. We measured CME using optical coherence tomography (OCT) central foveal thickness, macular thickness and total macular volume.

RESULTS

We enrolled 243 patients from January to June 2015, and 35% received diclofenac, 32.9% bromfenac and 32.1% nepafenac. When we compared pre-operative to three weeks to two months, bromfenac was more effective in reducing foveal volume (21.3 and 35.4 mm³, respectively), compared with the diclofenac (1.3 and 11.5 mm³, respectively), and the nepafenac group, became more edematous 6.4 and 5.3, respectively. Totally 133 patients completed the post-surgical satisfaction questionnaire. Patients complained of eye stickiness in 13.8% whom we gave nepafenac, versus 10.3% whom we gave diclofenac sodium, and in 0 whom we gave bromfenac.

CONCLUSION

Bromfenac is the best tolerated and is more effective than diclofenac and nepafenac in reducing CME after phacoemulsification.

Effects of Pranoprofen on Aqueous Humor Monocyte Chemoattractant Protein-1 Level and Pain Relief During Second-Eye Cataract Surgery

The aim of our present study is to evaluate the efficacy of pranoprofen eye drops as pain relief during sequential second-eye cataract surgery and to investigate the possible mechanism. Seventy-six patients scheduled for bilateral sequential cataract surgery were randomly assigned to two groups: (1) treatment group (administered pranoprofen eye drops), or (2) control group (administered artificial tears). Preoperative anxiety and intraoperative pain were assessed. Monocyte chemoattractant protein 1 (MCP-1) in the aqueous humor was measured with a suspension cytokine array. An extracapsular lens extraction model was established in the Wistar rat and the MCP-1 concentrations were measured with an enzyme-linked immunosorbent assay. We found that in the control group, the pain scores were significantly higher during second-eye surgery than during first-eye surgery (both scores P < 0.001). In the treatment group, there was no significant difference in the pain scores during first-eye and second-eye surgery (both scores P > 0.1). The pain during second-eye surgery was significantly lower in the treatment group than in the control group (both scores P < 0.01). And in the 1-week and 6-week interval subgroups, the pain scores during second-eye surgery were significantly lower in the treatment group than the control group (P = 0.047 and P = 0.035, respectively). While the second-eye MCP-1 level was significantly lower after a 1-week interval in the treatment group than in the control group (P = 0.012), but did not differ significantly after a 6-week interval (P > 0.1). A parallel trend in the MCP-1 concentration was detected in the rat model. In conclusion, the preoperative administration of pranoprofen eye drops reduced the perceived pain during second-eye cataract surgery, especially when performed after 1-week and 6-week intervals between the first-eye and second-eye surgery. MCP-1, a pain-related cytokine, was associated with the pain-relief mechanism of pranoprofen when second-eye surgery was performed 1 week after second-eye surgery.

Downregulation of hypoxia-inducible factor-1α contributes to impaired megakaryopoiesis in immune thrombocytopenia

Impaired megakaryocyte maturation and exaggerated platelet destruction play a pivotal role in the pathogenesis of immune thrombocytopenia (ITP). Previous studies have shown that HIF-1α promotes the homing and engraftment of haematopoietic stem cells (HSCs), thereby stimulating HSC differentiation. However, whether HIF-1α plays a role in megakaryocytic maturation and platelet destruction in ITP remains elusive. Using enzyme-linked immunosorbent assays (ELISAs), we demonstrated that there were lower HIF-1α levels in the bone marrow (BM) of ITP patients than in that of healthy donors and patients with chemotherapy-related thrombocytopenia. Subjects with lower megakaryocyte (<100/slide) and platelet (<30 × 109/L) counts exhibited significantly decreased BM HIF-1α levels, compared to those with higher megakaryocyte (≥100/slide) and platelet (≥30 × 109/L) counts. To test whether HIF-1α regulates megakaryopoiesis and platelet production, megakaryocytes derived from mouse BM cells were treated with an HIF-1α activator (IOX-2; 50 µM) or inhibitor (PX-478; 50 µM). PX-478 significantly decreased HIF-1α expression, cell size, and the populations of CD41-positive and high-ploidy cells. Importantly, to evaluate the role of HIF-1α as a potential therapeutic target in ITP, mouse BM cells were incubated with plasma from ITP patients in the presence or absence of IOX-2. IOX-2 significantly attenuated the ITP plasma-induced decrease in cell size as well as the proportions of CD41-positive and high-ploidy cells. In addition, IOX-2 increased the number of megakaryocytes from mouse BM cells treated with ITP plasma. Our findings indicate that decreased HIF-1α may contribute to impaired megakaryopoiesis in ITP, and HIF-1α may provide a potential therapy for ITP patients.

Supplementary Material to this article is available online at www.thrombosis-online.com.

Diabetic retinopathy: new therapeutic perspectives based on pathogenic mechanisms

Diabetic retinopathy (DR) is the leading cause of visual impairment and preventable blindness and represents a significant socioeconomic cost for healthcare systems worldwide. In early stages of DR the only therapeutic strategy that physicians can offer is a tight control of the risk factors for DR (mainly blood glucose and blood pressure). The currently available treatments for DR are applicable only at advanced stages of the disease and are associated with significant adverse effects. Therefore, new treatments for the early stages of DR are needed. However, in early stages of DR invasive treatments such as intravitreal injections are too aggressive, and topical treatment seems to be an emerging route. In the present review, therapeutic strategies based on the main pathogenic mechanisms involved in the development of DR are reviewed. The main gap in the clinical setting is the treatment of early stages of DR and, therefore, this review emphasizes in this issue by giving an overview of potential druggable targets. By understanding of disease-specific pathogenic mechanisms, biological heterogeneity and progression patterns in early and advanced DR a more personalised approach to patient treatment will be implemented.

A novel hydrogel with dual temperature and pH responsiveness based on a nanostructured lipid carrier as an ophthalmic delivery system: enhanced trans-corneal permeability and bioavailability of nepafenac

A schematic illustration of a novel formulation that can be instilled on the surface of eyes (A) and the results of in vivo studies (B and C).