Ocular complications of diabetes mellitus

Predictors and Outcomes of Vitrectomy and Silicone Oil Injection in Advanced Diabetic Retinopathy

PURPOSE

To evaluate visual and anatomical results and identify factors that influence vitrectomy and silicone oil (SO) injection outcomes in proliferative diabetic retinopathy (PDR).

METHODS

This retrospective study included 236 eyes with PDR that were undergoing vitrectomy and SO injection with >3-month follow-up. The primary outcomes were final best-corrected visual acuity (BCVA) and retinal attachment rate.

RESULTS

At the final visit (mean, 88 ± 58 weeks), complete, partial, and no retinal attachment were observed in 86.9%, 10.6%, and 2.5% of patients, respectively. A total of 155 eyes had experienced SO removal, while 81 had SO in place. The mean initial BCVA was 1.9 ± 0.7 logarithm of the minimum angle of resolution (logMAR) and significantly improved to 1.7 ± 0.8 logMAR (p = 0.001). Initial macular detachment (adjusted odds ratio [AOR], 0.25), development of iatrogenic break (AOR, 0.25), and use of heavy SO (AOR, 0.13) were independently associated with a lower risk of final retinal attachment, and SO removal was associated with a higher incidence (AOR, 7.55). Better baseline BCVA was associated with a higher risk of final BCVA ≥20 / 200.

CONCLUSIONS

Despite an encouraging outcome based on anatomical data in advanced PDR treated with vitrectomy and SO, the functional prognosis was not satisfying for patients. Eyes with better vision at baseline had a more favorable prognosis, whereas eyes with initial macular detachment, intraoperative iatrogenic break, or heavy SO showed more unfavorable outcomes. In selected cases, extending the time of SO use did not worsen the prognosis.

Retinal vessel diameters and reactivity in diabetes mellitus and/or cardiovascular disease

Background

Retinal vessel calibre and vascular dilation/constriction in response to flicker light provocation may provide a measure distinguishing patients suffering from diabetes mellitus and/or cardiovascular disease.

Methods

One hundred and sixteen age and sex matched patients with diabetes mellitus (DM), cardiovascular disease (CVD) and both DM and CVD (DM + CVD) underwent systemic and intraocular pressure measurements. Retinal vessel calibres were assessed using a validated computer-based program to compute central retinal artery and vein equivalents (CRVE) from monochromatic retinal images. Vessel dilation and constriction responses to flicker light provocation were assessed by continuous retinal vessel diameter recordings. Plasma endothelial markers von Willebrand factor (vWf) and soluble E selectin (sEsel) were measured by ELISA.

Results

Retinal vessel calibres were comparable across groups but CRVE correlated significantly with disease duration in DM patients (r = 0.57, p < 0.001). Patients suffering DM only exhibited reduced arterial vasomotion at rest and reduced arterial constriction following flicker light induced vessel dilation compared to patients with CVD and those suffering both CVD + DM (p = 0.030). Patients suffering from CVD + DM exhibited significant differences between each flicker cycle in regards to arterial maximum constriction (p = 0.006) and time needed to reach arterial maximum dilation (p = 0.004), whereas the other two groups did not show such inconsistencies between individual flicker cycles. vWf was raised in CVD + DM compared to the other two groups (p ≤ 0.02), whilst sEsel was raised in CVD + DM compared to DM alone (p = 0.044).

Conclusions

Dynamic retinal vascular calibres as obtained by continuous diameter measurements using flicker light provocation can reveal subtle differences between groups suffering from CVD with and without DM. This difference in reaction pattern and lack of arterial constriction in DM may provide a suitable marker to monitor progression.

Ocular progenitor cells and current applications in regenerative medicines - Review

The recent emerging field of regenerative medicine is to present solutions for chronic diseases which cannot be sufficiently repaired by the body's own mechanisms. Stem cells are undifferentiated biological cells and have the potential to develop into many different cell types in the body during early life and growth. Self renewal and totipotency are the characteristic features of stem cells and it holds a promising result for treating various diseases like diabetic foot ulcer, heart diseases, lung diseases, Autism, Skin diseases, arthritis including eye disease. Failure of complete recovery of eye diseases and complications that follow conventional treatments have shifted search to a new form of regenerative medicine using Stem cells. The ocular progenitor cells are remarkable in stem cell biology and replenishing degenerated cells despite being present in low quantity and quiescence in our body has a high therapeutic value. In this paper we have review the applications on ocular progenitor stem cells in treatment of human eye diseases and address the strategies that have been exploited in an effort to regain visual function in the advance treatment of stem cells without any side effects and also present the significance in advance stem cell research.

Risk Factors of Hyperglycemia in Patients After a First Episode of Acute Pancreatitis: A Retrospective Cohort

OBJECTIVES

The aim of this study was to evaluate the risk factors for hyperglycemia development after a first episode of acute pancreatitis (AP).

METHODS

Three hundred and ten patients treated for AP were retrospectively evaluated. Hyperglycemia was determined by fasting blood glucose. All data were collected from the medical records room database and a follow-up telephone call.

RESULTS

The incidence rate of hyperglycemia was obviously increased 5 years after the event. Hazard ratios (HRs) of developing hyperglycemia in patients with hyperlipidemia, fatty liver, and hypertension were 2.52 (P < 0.001), 1.87 (P = 0.01), and 1.78 (P = 0.017), respectively. Patients of biliary origin that underwent endoscopic retrograde cholangiopancreatography presented a 4.62-fold greater risk than those managed conservatively. Other risk factors were random blood glucose greater than 8.33 mmol/L (HR, 4.19; P < 0.001), lactate dehydrogenase greater than 350 U/L (HR, 1.99; P = 0.017), calcium less than 1.75 mmol/L (HR, 3.86; P = 0.004), and elevated creatine kinase (HR, 2.74; P = 0.001). Patients with AB blood type showed 2.92-fold greater risk compared with those with O blood type. Among them, hyperlipidemia and hyperglycemia on admission were the only independent risk factors (both P < 0.05).

CONCLUSIONS

Hyperlipidemia, fatty liver, hypertension, endoscopic retrograde cholangiopancreatography treatment, acute hyperglycemia, elevated lactate dehydrogenase and creatine kinase, decreased calcium, and AB blood type were risk factors for hyperglycemia development after AP.

The association between diabetes and dermal microvascular dysfunction non-invasively assessed by laser Doppler with local thermal hyperemia: a systematic review with meta-analysis

Background/Introduction

Diabetes and cardiovascular disease develop in concert with metabolic abnormalities mirroring and causing changes in the vasculature, particularly the microcirculation. The microcirculation can be affected in different parts of the body of which the skin is the most easily accessible tissue.

Purpose

The association between diabetes and dermal microvascular dysfunction has been investigated in observational studies. However, the strength of the association is unknown. Therefore we conducted a systematic review with meta-analysis on the association between diabetes and dermal microvascular dysfunction as assessed by laser Doppler/laser speckle contrast imaging with local thermal hyperaemia as non-invasive indicator of microvascular functionality.

Methods

PubMed and Ovid were  systematically searched for eligible studies through March 2015. During the first selection, studies were included if they were performed in humans and were related to diabetes or glucose metabolism disorders and to dermal microcirculation. During the second step we selected studies based on the measurement technique, measurement location (arm or leg) and the inclusion of a healthy control group. A random effects model was used with the standardised mean difference as outcome measure. Calculations and imputation of data were done according to the Cochrane Handbook.

Results

Of the 1445 studies found in the first search, thirteen cross-sectional studies were included in the meta-analysis, comprising a total of 857 subjects. Resting blood flow was similar between healthy control subjects and diabetes patients. In contrast, the microvascular response to local skin heating was reduced in diabetic patients compared to healthy control subjects [pooled effect of −0.78 standardised mean difference (95% CI −1.06, −0.51)]. This effect is considered large according to Cohen’s effect size definition. The variability in effect size was high (heterogeneity 69%, p < 0.0001). However, subgroup analysis revealed no difference between the type and duration of diabetes and other health related factors, indicating that diabetes per se causes the microvascular dysfunction.

Conclusion

Our meta-analysis shows that diabetes is associated with a large reduction of dermal microvascular function in diabetic patients. The local thermal hyperaemia methodology may become a valuable non-invasive tool for diagnosis and assessing progress of diabetes-related microvascular complications, but standardisation of the technique and quality of study conduct is urgently required.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-016-0487-1) contains supplementary material, which is available to authorized users.

Vitrectomy for complications of proliferative diabetic retinopathy in young adults: clinical features and surgical outcomes

PURPOSE

To investigate the clinical manifestations and surgical results after vitrectomy for proliferative diabetic retinopathy (PDR) in young patients.

METHODS

Clinical features of patients between 18 to 40 years old who received vitrectomy for PDR between January 2009 and January 2015 were retrospectively reviewed. Those older than 40 years who received vitrectomy for PDR during the same period were retrospectively enrolled and compared as the control group.

RESULTS

There were 68 eyes (52 patients) in the study group and 77 eyes (61 patients) in the control group. The average age at operation was 33.15 ± 4.92 years and 56.67 ± 7.52 years, respectively (p < 0.001). At presentation, those in the study group had significantly higher proportions of active fibrovascular proliferation and traction retinal detachment, and with significantly higher-severity gradings than those in the control group. After operation, the recurrent detachment rates were 13.2% in the study group and 1.3% in the control group (p = 0.006), and the final anatomical success rates were 91.2% in the study group and 100% in the control group (p = 0.009). The most significant risk factor for poor visual outcome in the study group was neovascular glaucoma (NVG) (p = 0.001). Patients with Type 1 and Type 2 diabetes mellitus subgroups shared similar clinical features and visual outcome.

CONCLUSIONS

Younger patients who received vitrectomy for PDR presented with more severe anatomical features at the time of vitrectomy and had a higher rate of post-operative recurrent detachment. More than 90% achieved final anatomical success. NVG was associated with worse visual outcome.

The Relationship between Cardiovascular Autonomic Dysfunction and Ocular Abnormality in Chinese T2DM

OBJECTIVE

This study aims to explore the relationship between autonomic nerve dysfunction-assessed by cardiovascular autonomic neuropathy risk score (CAN-RS)-and ocular abnormality in Chinese type 2 diabetes mellitus (T2DM).

METHOD

This is a cross-sectional study. A total of 335 subjects with T2DM were enrolled. The state of visual acuity, the lens, the vitreous, and the fundus were tested by professional ophthalmic instruments. The electrochemical skin conductance (ESC) of the hands and feet was measured by SUDOSCAN, from which a cardiovascular autonomic neuropathy risk score (CAN-RS) was calculated. Receiver operating characteristic (ROC) curves were drawn to evaluate the feasibility and accuracy of CAN-RS in diabetic oculopathy screening.

RESULTS

Abnormalities of the lens, vitreous, and fundus accounted for 7.8%, 5.1%, and 9.9%, respectively, in this study. The means of hands and feet ESC were higher than 60 μS, and CAN-RS was 33.1 ± 14.8%. In logistic regression analysis, CAN-RS was positively associated with lens (OR = 1.055, P < 0.001) and vitreous (OR = 1.044, P < 0.01) abnormality. The area under ROC to detect lens and vitreous abnormality was 0.713 and 0.725, respectively.

CONCLUSION

CAN-RS, a cardiac autonomic nerve dysfunction index calculated by SUDOSCAN, may be a promising index for lens and vitreous abnormality screening in T2DM patients. Further studies are needed to confirm the conclusion.

Dexamethasone Intravitreal Implant at the Time of Cataract Surgery in Eyes with Diabetic Macular Edema

Purpose

To determine the potential role of intraoperative dexamethasone intravitreal implant (DEX-I) in reducing diabetic macular edema (DME) worsening after phacoemulsification.

Methods

This was a prospective study on 19 eyes of 19 patients with type 2 diabetes mellitus with DME and cataract. Mean preoperative Early Treatment Diabetic Retinopathy Study visual acuity (VA) was 16.7 letters. Mean foveal thickness (FT) was 451 μm. The DME was naive in 11 eyes and refractory in 8 eyes. All eyes underwent a standard phacoemulsification and intraocular lens implantation; DEX-I was injected at the end of surgery. Follow-up was performed at 1 week and then monthly until DME recurrence (up to 8 months).

Results

At 1 week, mean VA improved by 15 letters (range 0-29 letters) and mean FT decreased by 147 μm (range 69-236 μm). Improvement consolidated at month 1, with a mean VA improvement of 18 letters (range 3-32 letters) and a mean improvement in FT of 193 μm (range 76-304 μm), remaining stable at month 2 after surgery in all eyes. The DME recurred in 1 eye at month 3, in 14 eyes (73.8%) between months 4 and 5, and after month 6 in 4 eyes (21%). Refractory DMEs demonstrated the same benefit but recurred earlier than naive ones (4 months versus 5.8 months, p<0.01).

Conclusions

Intraoperative DEX-I prevents DME worsening after phacoemulsification. Its positive effects last for at least 3 months.

Ophthalmologic evaluation in geriatric patients: Assessment of consistency between patients' complaints and ocular diagnoses

PURPOSE

This study aimed to assess the consistency between patients' complaints and their eye diseases.

DESIGN

Cross-sectional study.

METHODS

RESULTS: The frequencies of at least one newly diagnosed visually important ocular disease were 25.9%, 27.0%, and 45.3% in groups 1, 2, and 3, respectively (p<0.001). The same frequencies were significantly higher in patients >75 years of age compared with the younger group (59.1% vs. 22.0%, p<0.001). Although these values were statistically significant in patients ≤75 years of age (p<0.001), they were insignificant in patients >75 years of age according to type of complaints (p=0.773). Patients with diabetes mellitus exhibited significantly lower vision, higher rate of visually important ocular diseases, and higher intraocular pressure readings than patients without diabetes mellitus (p=0.009, 0.015, and 0.002, respectively).

CONCLUSIONS

Visually important ocular diseases were diagnosed approximately in a quarter of patients who had no complaints about decrease in vision and in more than half of the oldest geriatric patients (>75years) irrespective of the type of complaints.

Association of vascular endothelial growth factor -634G/C and receptor for advanced glycation end products G82S gene polymorphisms with diabetic retinopathy

AIM

To investigate the association of receptor for advanced glycation end products (RAGE) G82S and vascular endothelial growth factor (VEGF) -634 G/C gene polymorphisms with diabetic retinopathy (DR).

METHODS

Our cross-sectional study included 61 diabetic patients, 12 of them had proliferative diabetic retinopathy (PDR), 15 had non proliferative diabetic retinopathy (NPDR), 34 had no diabetic retinopathy (NDR) and 61 healthy controls. Participants were tested for RAGE G82S and VEGF -634 G/C polymorphisms by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

We found a significant association between VEGF -634 G/C polymorphism and PDR as PDR patients had increased incidence of VEGF -634 CC genotype compared to NDR patients [odds ratio for CC vs (GC+GG)=6.5, 95% CI=1.5-27.8, P=0.021]. Also VEGF -634 CC genotype and C allele were significantly higher in the PDR than in NPDR patients, which is a novel finding in our study (P=0.024, 0.009 respectively). The mean triglycerides level was significantly higher in diabetic patients with CC genotype (P=0.01) as compared to patients with other genotypes. All cases and control subjects were of the same heterozygous RAGE 82G/S genotype.

CONCLUSION

Patients carrying VEGF -634 C polymorphism have a higher risk of PDR development, so VEGF -634 G/C polymorphism could be used as a predictive marker for PDR in diabetic patients. We could not find a significant association between RAGE G82S polymorphism and DR.

The relationship of systemic markers of renal function and vascular function with retinal blood vessel responses

PURPOSE

To test the hypothesis of a significant relationship between systemic markers of renal and vascular function (processes linked to cardiovascular disease and its development) and retinal microvascular function in diabetes and/or cardiovascular disease.

METHODS

Ocular microcirculatory function was measured in 116 patients with diabetes and/or cardiovascular disease using static and continuous retinal vessel responses to three cycles of flickering light. Endothelial function was evaluated by von Willebrand factor (vWf), endothelial microparticles and soluble E selectin, renal function by serum creatinine, creatinine clearance and estimated glomerular filtration rate (eGFR). HbA1c was used as a control index.

RESULTS

Central retinal vein equivalence and venous maximum dilation to flicker were linked to HbA1c (both p < 0.05). Arterial reaction time was linked to serum creatinine (p = 0.036) and eGFR (p = 0.039); venous reaction time was linked to creatinine clearance (p = 0.018). Creatinine clearance and eGFR were linked to arterial maximum dilatation (p < 0.001 and p = 0.003, respectively) and the dilatation amplitude (p = 0.038 and p = 0.048, respectively) responses in the third flicker cycle. Of venous responses to the first flicker cycle, HbA1c was linked to the maximum dilation response (p = 0.004) and dilatation amplitude (p = 0.017), vWf was linked to the maximum constriction response (p = 0.016), and creatinine clearance to the baseline diameter fluctuation (p = 0.029). In the second flicker cycle, dilatation amplitude was linked to serum creatinine (p = 0.022).

CONCLUSIONS

Several retinal blood vessel responses to flickering light are linked to glycaemia and renal function, but only one index is linked to endothelial function. Renal function must be considered when interpreting retinal vessel responses.

Osteogenic differentiation of human lens epithelial cells might contribute to lens calcification

Calcification of the human lens has been described in senile cataracts and in young patients with congenital cataract or chronic uveitis. Lens calcification is also a major complication of cataract surgery and plays a role in the opacification of intraocular lenses. A cell-mediated process has been suggested in the background of lens calcification, but so far the exact mechanism remained unexplored. Lens calcification shares remarkable similarities with vascular calcification; in both pathological processes hydroxyapatite accumulates in the soft tissue. Vascular calcification is a regulated, cell-mediated process in which vascular cells undergo osteogenic differentiation. Our objective was to investigate whether human lens epithelial cells (HuLECs) can undergo osteogenic transition in vitro, and whether this process contributes to lens calcification. We used inorganic phosphate (Pi) and Ca to stimulate osteogenic differentiation of HuLECs. Osteogenic stimuli (2.5mmol/L Pi and 1.2mmol/L Ca) induced extracellular matrix mineralization and Ca deposition in HuLECs with the critical involvement of active Pi uptake. Osteogenic stimuli almost doubled mRNA expressions of osteo-/chondrogenic transcription factors Runx2 and Sox9, which was accompanied by a 1.9-fold increase in Runx2 and a 5.5-fold increase in Sox9 protein expressions. Osteogenic stimuli induced mRNA and protein expressions of alkaline phosphatase and osteocalcin in HuLEC. Ca content was higher in human cataractous lenses, compared to non-cataractous controls (n=10). Osteocalcin, an osteoblast-specific protein, was expressed in 2 out of 10 cataractous lenses. We conclude that osteogenic stimuli induce osteogenic differentiation of HuLECs and propose that this mechanism might play a role in lens calcification.

Study of Association between Pre-Senile Cataracts and the Polymorphisms rs2228000 in XPC and rs1042522 in p53 in Spanish Population

Purpose

To determine if the presence of certain polymorphisms in the DNA repair gene XPC and the apoptosis inductor gene p53 is associated with pre-senile cataract development.

Methods

We have performed a retrospective study over three groups of patients. The group with pre-senile cataract formed by 72 patients younger than 55 with cataract surgery. The group with senile cataract formed by 101 patients older than 55 with cataract surgery. The group without cataract was formed by 42 subjects older than 55 without lens opacities. We analyzed the presence of SNP rs2228000 from XPC and rs1042522 from p53; and the relationship between risk factors such as smoking, alcohol intake, hypertension or diabetes.

Results

The comparison of the genotype distribution in XPC, within the different groups, did not show any statistically significant association in any of our analysis (p>0,05). The comparison of the genotype distribution in p53 within the different groups did not show any statistically significant association (p>0,05); except for the comparison between the pre-senile cataract group and the group with senile cataract where the genotype Pro/Pro (C/C) in the recessive inheritance model showed a higher risk for developing pre-senile cataract (p = 0,031; OR = 1.04–15.97). This association decreased when we performed the analysis adjusting by the studied risk factors (p = 0.056).

Conclusions

Allelic variants in the gene XPC are not associated with an increased risk for developing pre-senile cataract. The presence of the genotype Pro/Pro in p53 might be associated with a major risk for developing pre-senile cataract.

Stem Cell Therapy for Treatment of Ocular Disorders

Sustenance of visual function is the ultimate focus of ophthalmologists. Failure of complete recovery of visual function and complications that follow conventional treatments have shifted search to a new form of therapy using stem cells. Stem cell progenitors play a major role in replenishing degenerated cells despite being present in low quantity and quiescence in our body. Unlike other tissues and cells, regeneration of new optic cells responsible for visual function is rarely observed. Understanding the transcription factors and genes responsible for optic cells development will assist scientists in formulating a strategy to activate and direct stem cells renewal and differentiation. We review the processes of human eye development and address the strategies that have been exploited in an effort to regain visual function in the preclinical and clinical state. The update of clinical findings of patients receiving stem cell treatment is also presented.

Dry Eye Syndrome in Patients with Diabetes Mellitus: Prevalence, Etiology, and Clinical Characteristics

There has been substantial progress in our understanding of the ocular surface system/lacrimal function unit in the past 15 years. Keratoconjunctivitis sicca, more commonly referred to as dry eye syndrome (DES), is the most frequently encountered condition and diabetes mellitus (DM) has been identified as one of the leading causes of DES. Poor glycemic control affects both the anterior and the posterior segments of the eye and increasing prevalence of diabetes-associated DES (DMDES) has been reported in recent years. The pathogenesis and specific features of DMDES remain uncertain and interventions are limited to those used in DES. This review outlines the pathogenesis, clinical manifestations, and the current preventive and treatment strategies for diabetes-related DES.

Hormetic and regulatory effects of lipid peroxidation mediators in pancreatic beta cells

Nutrient sensing mechanisms of carbohydrates, amino acids and lipids operate distinct pathways that are essential for the adaptation to varying metabolic conditions. The role of nutrient-induced biosynthesis of hormones is paramount for attaining metabolic homeostasis in the organism. Nutrient overload attenuate key metabolic cellular functions and interfere with hormonal-regulated inter- and intra-organ communication, which may ultimately lead to metabolic derangements. Hyperglycemia and high levels of saturated free fatty acids induce excessive production of oxygen free radicals in tissues and cells. This phenomenon, which is accentuated in both type-1 and type-2 diabetic patients, has been associated with the development of impaired glucose tolerance and the etiology of peripheral complications. However, low levels of the same free radicals also induce hormetic responses that protect cells against deleterious effects of the same radicals. Of interest is the role of hydroxyl radicals in initiating peroxidation of polyunsaturated fatty acids (PUFA) and generation of α,β-unsaturated reactive 4-hydroxyalkenals that avidly form covalent adducts with nucleophilic moieties in proteins, phospholipids and nucleic acids. Numerous studies have linked the lipid peroxidation product 4-hydroxy-2E-nonenal (4-HNE) to different pathological and cytotoxic processes. Similarly, two other members of the family, 4-hydroxyl-2E-hexenal (4-HHE) and 4-hydroxy-2E,6Z-dodecadienal (4-HDDE), have also been identified as potential cytotoxic agents. It has been suggested that 4-HNE-induced modifications in macromolecules in cells may alter their cellular functions and modify signaling properties. Yet, it has also been acknowledged that these bioactive aldehydes also function as signaling molecules that directly modify cell functions in a hormetic fashion to enable cells adapt to various stressful stimuli. Recent studies have shown that 4-HNE and 4-HDDE, which activate peroxisome proliferator-activated receptor δ (PPARδ) in vascular endothelial cells and insulin secreting beta cells, promote such adaptive responses to ameliorate detrimental effects of high glucose and diabetes-like conditions. In addition, due to the electrophilic nature of these reactive aldehydes they form covalent adducts with electronegative moieties in proteins, phosphatidylethanolamine and nucleotides. Normally these non-enzymatic modifications are maintained below the cytotoxic range due to efficient cellular neutralization processes of 4-hydroxyalkenals. The major neutralizing enzymes include fatty aldehyde dehydrogenase (FALDH), aldose reductase (AR) and alcohol dehydrogenase (ADH), which transform the aldehyde to the corresponding carboxylic acid or alcohols, respectively, or by biding to the thiol group in glutathione (GSH) by the action of glutathione-S-transferase (GST). This review describes the hormetic and cytotoxic roles of oxygen free radicals and 4-hydroxyalkenals in beta cells exposed to nutritional challenges and the cellular mechanisms they employ to maintain their level at functional range below the cytotoxic threshold.

Ranibizumab: A Review of Its Use in the Treatment of Diabetic Retinopathy in Patients With Diabetic Macular Edema

Objective: To evaluate the pharmacotherapy role of ranibizumab, a vascular endothelial growth factor (VEGF) inhibitor, for the treatment of diabetic retinopathy (DR) in patients with diabetic macular edema (DME). Data Sources: PubMed, Science Direct, Google Scholar, and ClinicalTrials.gov searches (January 2000-May 2015) were conducted for articles published in English, and limited to clinical trials using the key words ranibizumab, DR, DME, anti-VEGF, and DR treatment. Study Selection and Data Extraction: Following PubMed, Science Direct, Google Scholar, and ClinicalTrials.gov searches, 4 clinical trials were identified and included in this review. Phase III/IV studies evaluating the clinical efficacy of ranibizumab versus placebo, ranibizumab versus laser, and ranibizumab versus other anti-VEGF agents were selected and evaluated. Data Synthesis: Ranibizumab administered to patients with DME for 12 to 36 months improved and prevented worsening of visual acuity. At month 36 the ranibizumab-treated eyes had a >2 or >3 step DR improvement compared with the sham crossover eyes. Ranibizumab was also found to be superior to laser treatment. Patients receiving ranibizumab gained 6.0 letters, improved tritan and protan color contrast thresholds, and demonstrated improved retinal sensitivity versus the subjects receiving laser treatment who lost 0.9 letters. When ranibizumab was compared with other anti-VEGF agents (aflibercept, pegaptanib, and bevacizumab), it was not always demonstrated to be significantly superior. Conclusion: Ranibizumab has been shown to be safe and efficacious for use in the treatment of DR in patients with DME. Thus, it is an alternative treatment approach to laser photocoagulation therapy.

Consumption of Polyphenol-Rich Zingiber Zerumbet Rhizome Extracts Protects against the Breakdown of the Blood-Retinal Barrier and Retinal Inflammation Induced by Diabetes

The present study investigates the amelioration of diabetic retinopathy (DR) by Zingiber zerumbet rhizome ethanol extracts (ZZRext) in streptozotocin-induced diabetic rats (STZ-diabetic rats). ZZRext contains high phenolic and flavonoid contents. STZ-diabetic rats were treated orally with ZZRext (200, 300 mg/kg per day) for three months. Blood-retinal barrier (BRB) breakdown and increased vascular permeability were found in diabetic rats, with downregulation of occludin, and claudin-5. ZZRext treatment effectively preserved the expression of occludin, and claudin-5, leading to less BRB breakdown and less vascular permeability. Retinal histopathological observation showed that the disarrangement and reduction in thickness of retinal layers were reversed in ZZRext-treated diabetic rats. Retinal gene expression of tumor necrosis factor-α, interleukin (IL)-1β, IL-6, vascular endothelial growth factor, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 were all decreased in ZZRext-treated diabetic rats. Moreover, ZZRext treatment not only inhibited the nuclear factor κB (NF-κB) activation, but also downregulated the protein expression of p38 mitogen-activated protein kinase (MAPK) in diabetic retina. In conclusion, the results suggest that the retinal protective effects of ZZRext occur through improved retinal structural change and inhibiting retinal inflammation. The antiretinopathy property of ZZRext might be related to the downregulation of p38 MAPK and NF-κB signal transduction induced by diabetes.