IL-8 and VEGFR-2 polymorphisms modulate long-term functional response to intravitreal ranibizumab in exudative age-related macular degeneration

CFH (rs1061170, rs1410996), KDR (rs2071559, rs1870377) and KDR and CFH Serum Levels in AMD Development and Treatment Efficacy

BACKGROUND

Age-related macular degeneration (AMD) is a major global health problem as it is the leading cause of irreversible loss of central vision in the aging population. Av-vascular endothelial growth factor (anti-VEGF) therapies have been shown to be effective, but they do not respond optimally to all patients.

OBJECTIVE

This study investigates the genetic factors associated with susceptibility to AMD and response to treatment, focusing on key polymorphisms in the CFH (rs1061170, rs1410996) and KDR (rs2071559, rs1870377) genes and the association of CFH and KDR serum levels in patients with AMD.

RESULTS

A cohort of 255 patients with early AMD, 252 patients with exudative AMD, and 349 healthy controls underwent genotyping analysis, which revealed significant associations between CFH polymorphisms and the risk of exudative AMD. The CFH rs1061170 CC genotype was associated with an increased risk of early AMD (p = 0.046). For exudative AMD, the CFH rs1061170 TC + CC genotype increased odds (p < 0.001), while the rs1410996 GA + AA genotype decreased odds (p < 0.001). Haplotypes of CFH SNPs were associated with decreased odds of AMD. In terms of response to treatment, none of the SNPs were associated with the response to anti-VEGF treatment. We also found that both early and exudative AMD patients had lower CFH serum levels compared to the control group (p = 0.038 and p = 0.006, respectively). Exudative AMD patients with the CT genotype of CFH rs1061170 had lower CFH serum levels compared to the control group (p = 0.035). Exudative AMD patients with the GG genotype of CFH rs1410996 also had lower CFH serum levels compared to the control group (p = 0.021).

CONCLUSIONS

CFH polymorphisms influence susceptibility to AMD but do not correlate with a response to anti-VEGF therapy. Further research is imperative to fully evaluate the developmental significance, treatment efficacy, and predictive role in influencing susceptibility to anti-VEGF therapy for KDR and CFH.

Interleukin-8 Promoter Polymorphism -251 A/T and Treatment Response in Neovascular Age-related Macular Degeneration

Purpose

Interleukin-8 (IL-8) is a potent pro-angiogenic and pro-inflammatory chemokine, suggested to hold a role in neovascular age-related macular degeneration (nAMD). Our aim is to study the association of the single-nucleotide polymorphism -251 A/T (rs4073) in the IL-8 promoter region with the treatment response to intravitreal anti-vascular endothelial growth factor (VEGF) injections in nAMD.

Patients and Methods

This is a prospective study of treatment-naïve patients with nAMD. Treatment response after a loading dose of three intravitreal anti-VEGF injections was defined as functional response based on change in visual acuity, and morphological response based on change in central retinal thickness (CRT) and intraretinal fluid on optical coherence tomography. Morphological response was categorized in good, partial, and poor responders. Blood DNA was analyzed for -251 A/T genotype.

Results

The IL-8 promoter polymorphism -251 A/T was not significantly associated to functional treatment response (P=0.09). No significant association was found between genotype and morphological treatment response (P=0.799). Older age was significantly associated to good morphological responders compared to partial and poor responders (P=0.014).

Conclusion

The IL-8 polymorphism -251 A/T is not associated to morphological nor functional treatment response to intravitreal anti-VEGF injections in patients with nAMD.

Influence of Genetic Polymorphisms on the Short-Term Response to Ranibizumab in Patients With Neovascular Age-Related Macular Degeneration

Purpose

To determine whether genetic risk single nucleotide polymorphisms (SNPs) for age-related macular degeneration (AMD) influence short-term response to intravitreal ranibizumab treatment.

Methods

Forty-four treatment-naive AMD patients were included in a prospective observational study. They underwent three monthly injections of intravitreal ranibizumab for neovascular AMD. After an initial clinical examination (baseline measurement), a follow-up visit was performed to determine treatment response one month after the third injection (treatment evaluation). Patients were evaluated based on ophthalmoscopy, fluorescein angiography, optical coherence tomography (OCT), and OCT angiography. Peripheral venous blood was collected for DNA analysis at baseline visit. Patients were genotyped for single-nucleotide polymorphisms within AMD-relevant genes and classified on good or poor responders based on visual acuity, central retinal thickness, intraretinal fluid, and subretinal fluid.

Results

One hundred ten AMD-associated SNPs have been analyzed. Six were found to be relevant when associated to ranibizumab treatment response. The genetic variants rs890293 (CYP2J2), rs11200638 (HTRA1), rs405509 (APOE), rs9513070 (FLT1), and rs8135665 (SLC16A8) predisposed patients to a good response, whereas rs3093077 (CRP) was associated with a poor response. FTL1, SLC16A8, and APOE were the SNPs that showed significance (P < 0.05) but did not pass Bonferroni correction.

Conclusions

This is the first study that links novel polymorphisms in genes such as CRP, SCL16A8, or CYP2J2 to treatment response to ranibizumab therapy. On the other hand, HTRA1, FLT1, and APOE are linked to a good ranibizumab response. These SNPs may be good candidates for short-term treatment response biomarkers in AMD patients. However, further studies will be necessary to confirm our findings.

Genetic Polymorphisms in VEGFR Coding Genes (FLT1/KDR) on Ranibizumab Response in High Myopia and Choroidal Neovascularization Patients

A severe form of myopia defined as pathologic/high myopia is the main cause of visual impairment and one of the most frequent causes of blindness worldwide. It is characterized by at least 6 diopters or axial length (AL) of eyeball > 26 mm and choroidal neovascularization (CNV) in 5 to 10% of cases. Ranibizumab is a humanized recombinant monoclonal antibody fragment targeted against human vascular endothelial growth factor A (VEGF-A) used in the treatment of CNV. It acts by preventing VEGF-A from interacting with its receptors (VEGFR-1 and -2) encoded by the FLT1 and KDR genes. Several studies found that the KDR and FLT1 genotypes may represent predictive determinants of efficacy in ranibizumab-treated neovascular age-related macular degeneration (nAMD) patients. We performed a retrospective study to evaluate the association of single nucleotide polymorphisms (SNPs) in VEGFR coding genes with the response rate to ranibizumab in patients with high myopia and CNV. In the association study of genotypes in FLT1 with the response to ranibizumab, we found a significant association between two FLT1 variants (rs9582036, rs7993418) with ranibizumab efficacy at the 12-month follow-up. About the KDR gene, we found that two KDR variants (rs2305948, rs2071559) are associated with best-corrected visual acuity (BCVA) improvement and KDR (rs2239702) is associated with lower rates of BCVA worsening considering a 12-month follow-up period.

Epigenomic signatures in age-related macular degeneration: Focus on their role as disease modifiers and therapeutic targets

Epigenetics is characterized by molecular modifications able to shape gene expression profiles in response to inner and external stimuli. Therefore, epigenetic elements are able to provide intriguing and useful information for the comprehension and management of different human conditions, including aging process, and diseases. On this subject, Age-related Macular Degeneration (AMD) represents one of the most frequent age-related disorders, dramatically affecting the quality of life of older adults worldwide. The etiopathogenesis is characterized by an interplay among multiple genetic and non-genetic factors, which have been extensively studied. Nevertheless, a deeper dissection of molecular machinery associated with risk, onset, progression and effectiveness of therapies is still missing. In this regard, epigenetic signals may be further explored to disentangle disease etiopathogenesis, the possible therapeutic avenues and the differential response to AMD treatment. This review will discuss the epigenomic signatures mostly investigated in AMD, which could be applied to improve the knowledge of disease mechanisms and to set-up novel or modified treatment options.

Roles of IL-8 -251A/T and +781C/T polymorphisms, IL-8 level, and the risk of age-related macular degeneration

OBJECTIVE

To clarify the association between IL-8 gene polymorphisms, IL-8 level, towards the risk of age-related macular degeneration (AMD).

METHODS

Meta-analysis was performed from available studies that investigated IL-8 -251A/T (rs4073) and +781C/T (rs2227306) polymorphisms and IL-8 levels in patients with AMD and controls.

RESULTS

Overall, the pooled result showed a significant association between AMD with allelic (T vs. C; OR 1.53; p = 0.005), dominant (TT + CT vs. CC; OR 1.95; p = 0.017), homozygous (TT vs. CC; OR 2.03; p = 0.039) and heterozygous (CT vs. CC; OR 1.92; p = 0.032) models of rs2227306; while subgroup analysis revealed a significant association between rs2227306 with wet AMD in allelic (T vs. C; OR 1.69; p = 0.016), recessive (TT vs. CT + CC; OR 1.81; p = 0.00007), and homozygous (TT vs. CC; OR 2.64; p = 0.003) models. No significant association was observed between rs4073 with AMD in all inheritance models. In parallel, patients with AMD, particularly wet AMD had an elevated level of IL-8 compared to control.

CONCLUSION

This meta-analysis suggests that patients with AMD or wet AMD have higher IL-8 levels compared to control, which is also supported by the evidence that carrier T allele of rs2227306 exhibited an increase in the risk of AMD or wet AMD. Thus, IL-8 +781C/T (rs2227306) polymorphism and the level of intraocular IL-8 may be useful as a biomarker for early detection and a therapeutic target of AMD.

Quiescent Neovascular Age-Related Macular Degeneration After Endophthalmitis

Purpose:

This article describes eyes that achieved extended remission of neovascular age-related macular degeneration (NVAMD) following acute endophthalmitis.

Methods:

Adults who presented to the Duke Eye Center with acute endophthalmitis over a 9-year period and had at least 3 months of follow-up were identified. A retrospective review of medical records was performed to collect clinical data including demographic information, examination findings, etiology, treatment, and outcomes.

Results:

A total of 133 eyes of 130 patients with endophthalmitis were identified. Of these, 15 eyes of 14 patients (11.3%) were receiving intravitreal antivascular endothelial growth factor (anti-VEGF) injections for NVAMD. Six of these 15 eyes (40%) did not require an anti-VEGF injection after endophthalmitis for a mean of 36.2 months. Endophthalmitis was injection-related in 5 of 6 eyes (83%) and Baerveldt glaucoma drainage device–related in 1 of 6 eyes (17%). Two of the 6 (33%) had culture-proven infectious endophthalmitis, whereas 4 of 6 (67%) had culture-negative endophthalmitis. Five of 6 eyes have required no anti-VEGF therapy to date; the remaining eye restarted intravitreal aflibercept therapy 9.3 months after endophthalmitis.

Conclusions:

Acute endophthalmitis may be associated with reduced activity of choroidal neovascularization in a subset of eyes with NVAMD.

Further understanding of epigenetic dysfunction of the retinal pigment epithelium in AMD

Introduction

Modulation of epigenetic mechanisms that contribute to retinal development may render the eye susceptible to age-related macular degeneration (AMD). Progression of AMD involves alterations of epigenome such as CpG methylation and histone modifications, and study of the epigenetic regulation of molecular/ cellular pathways associated with AMD might identify target epigenetic markers for treatment of AMD.

Areas covered

In this review, we provide an overview of the influence of epigenetic factors on signaling pathways/ related genes associated with AMD, mainly hypoxia, angiogenesis, inflammation, complement, and oxidative stress; and discuss the critical role of microRNAs in AMD.

Expert Opinion

Better understanding of epigenetic-mediated and microRNA-mediated regulation of the AMD disease-related pathways would help to assess the risk of developing AMD besides providing valuable insight on potential target candidates for AMD therapy.

Age-related macular degeneration: A two-level model hypothesis

Age-related diseases, including age-related macular degeneration (AMD), are of growing importance in a world where population ageing has become a dominant global trend. Although a wide variety of risk factors for AMD have been identified, age itself remains by far the most important risk factor, making it an urgent priority to understand the connections between underlying ageing mechanisms and pathophysiology of AMD. Ageing is both multicausal and variable, so that differences between individuals in biological ageing processes are the focus of a growing number of pathophysiological studies seeking to explain how ageing contributes to chronic, age-related conditions. The aim of this review is to integrate the available knowledge on the pathophysiology of AMD within the framework of the biology of ageing. One highly significant feature of biological ageing is systemic inflammation, which arises as a second-level response to a first level of molecular damage involving oxidative stress, mutations etc. Combining these insights, the various co-existing pathophysiological explanations in AMD arrange themselves according to a two-level hypothesis. Accordingly, we describe how AMD can be considered the consequence of age-related random accumulation of molecular damage at the ocular level and the subsequent systemic inflammatory host response thereof. We summarize evidence and provide original data to enlighten where evidence is lacking. Finally, we discuss how this two-level hypothesis provides a foundation for thoughts and future studies in prevention, prognosis, and intervention.

Müller cells in pathological retinal angiogenesis

Müller cells are the major glial cells spanning the entire layer of the retina and maintaining retinal structure. Under pathological conditions, Müller cells are involved in retinal angiogenesis, a process of growing new blood vessels from pre-existing capillaries. In response to hypoxia, high glucose, and inflammation conditions, multiple signaling pathways are activated in Müller cells, followed by the increased production of proangiogenic factors including vascular endothelial growth factor, basic fibroblast growth factor, matrix metalloproteinases, Netrin-4, and angiopoietin-like 4. Expression of antiangiogenic factors is also downregulated in Müller cells. Besides, proliferation and dedifferentiation of Müller cells facilitates retinal angiogenesis. In this review, we summarized molecular mechanisms of Müller cells-related retinal angiogenesis. The potential of Müller cells as a therapeutic target for retinal angiogenesis was also discussed.

Role of inflammatory factors in the effects of aflibercept or ranibizumab treatment for alleviating wet age-associated macular degeneration

Aflibercept and ranibizumab are novel drugs for effectively treating wet age-associated macular degeneration (AMD). In the present study, the effect of aflibercept and ranibizumab on wet AMD was compared. A total of 80 AMD patients were intravitreously treated with aflibercept (2.0 mg/dose, 40 participants) or ranibizumab (0.3 mg/dose, 40 participants). The mean visual acuity and central subfield thickness (CTS) were determined at baseline and each follow-up visit (every 4 weeks). ELISA was used to detect the expression of transforming growth factor-β1 (TGF-β1), monocyte chemoattractant protein 1 (MCP-1) and interleukin 6 (IL-6). The primary outcome was the mean change in visual acuity letter score (VAS) and CTS at 1 year. The VAS was markedly improved by 13.1 in the aflibercept group and by 11.0 in the ranibizumab group. In a subgroup of patients with an initial VAS of <69, the mean improvement in the VAS was 17.7 in the aflibercept group and 13.2 in the ranibizumab group (P<0.01). The mean CTS was markedly decreased by 141 in the aflibercept group and by 134 in the ranibizumab group. In the subgroup of patients with an initial VAS of <69, the mean CTS was decreased by 171 in the aflibercept group and by 154 in the ranibizumab group (P<0.01). However, the change of VAS and CTS was similar between the ranibizumab and aflibercept groups when the initial VAS was ≥69. No significant differences in serious adverse events were identified between the aflibercept and ranibizumab groups. The levels of TGF-β1, IL-6 and MCP-1 were decreased by the aflibercept and ranibizumab treatments. The decrease in the levels of the inflammatory factors was more obvious in patients with an initial VAS of <69 in comparison with that in patients with an initial VAS of ≥69. Negative correlations between the levels of TGF-β1, MCP-1 and IL-6 and the mean change of VAS when patients were treated with aflibercept or ranibizumab were identified among all ages. Positive correlations between the levels of TGF-β1, MCP-1 and IL-6 and the mean change of CTS were observed when the initial VAS of the patients was <69. In conclusion, the efficacy of aflibercept in treating patients with AMD was better than that of ranibizumab when the initial VAS of the patients was <69. The inhibition of inflammatory factors may be a secondary effect of aflibercept and ranibizumab treatment. The present study provides a useful reference for the clinical treatment of wet AMD (Chinese Clinical Trial Registry no. ChiCTR1800017782).

Association of Genetic Variants With Response to Anti-Vascular Endothelial Growth Factor Therapy in Age-Related Macular Degeneration

Importance

Visual acuity (VA) outcomes differ considerably among patients with neovascular age-related macular degeneration (nAMD) treated with anti-vascular endothelial growth factor (VEGF) drugs. Identification of pharmacogenetic associations may help clinicians understand the mechanisms underlying this variability as well as pave the way for personalized treatment in nAMD.

Objective

To identify genetic factors associated with variability in the response to anti-VEGF therapy for patients with nAMD.

Design, Setting, and Participants

In this multicenter genome-wide association study, 678 patients with nAMD with genome-wide genotyping data were included in the discovery phase; 1380 additional patients with nAMD were genotyped for selected common variants in the replication phase. All participants received 3 monthly injections of bevacizumab or ranibizumab. Clinical data were evaluated for inclusion/exclusion criteria from October 2014 to October 2015, followed by data analysis from October 2015 to February 2016. For replication cohort genotyping, clinical data collection and analysis (including meta-analysis) was performed from March 2016 to April 2017.

Main Outcomes and Measures

Change in VA after the loading dose of 3 monthly anti-VEGF injections compared with baseline.

Results

Of the 2058 included patients, 1210 (58.8%) were women, and the mean (SD) age across all cohorts was 78 (7.4) years. Patients included in the discovery cohort and most of the patients in the replication cohorts were of European descent. The mean (SD) baseline VA was 51.3 (20.3) Early Treatment Diabetic Retinopathy Study (ETDRS) score letters, and the mean (SD) change in VA after the loading dose of 3 monthly injections was a gain of 5.1 (13.9) ETDRS score letters (ie, 1-line gain). Genome-wide single-variant analyses of common variants revealed 5 independent loci that reached a P value less than 10 × 10-5. After replication and meta-analysis of the lead variants, rs12138564 located in the CCT3 gene remained nominally associated with a better treatment outcome (ETDRS letter gain, 1.7; β, 0.034; SE, 0.008; P = 1.38 × 10-5). Genome-wide gene-based optimal unified sequence kernel association test of rare variants showed genome-wide significant associations for the C10orf88 (P = 4.22 × 10-7) and UNC93B1 (P = 6.09 × 10-7) genes, in both cases leading to a worse treatment outcome. Patients carrying rare variants in the C10orf88 and UNC93B1 genes lost a mean (SD) VA of 30.6 (17.4) ETDRS score letters (ie, loss of 6.09 lines) and 26.5 (13.8) ETDRS score letters (ie, loss of 5.29 lines), respectively, after 3 months of anti-VEGF treatment.

Conclusions and Relevance

We propose that there is a limited contribution of common genetic variants to variability in nAMD treatment response. Our results suggest that rare protein-altering variants in the C10orf88 and UNC93B1 genes are associated with a worse response to anti-VEGF therapy in patients with nAMD, but these results require further validation in other cohorts.

Exploring the Use of Molecular Biomarkers for Precision Medicine in Age-Related Macular Degeneration

Precision medicine aims to improve patient care by adjusting medication to each patient's individual needs. Age-related macular degeneration (AMD) is a heterogeneous eye disease in which several pathways are involved, and the risk factors driving the disease differ per patient. As a consequence, precision medicine holds promise for improved management of this disease, which is nowadays a main cause of vision loss in the elderly. In this review, we provide an overview of the studies that have evaluated the use of molecular biomarkers to predict response to treatment in AMD. We predominantly focus on genetic biomarkers, but also include studies that examined circulating or eye fluid biomarkers in treatment response. This involves studies on treatment response to dietary supplements, response to anti-vascular endothelial growth factor, and response to complement inhibitors. In addition, we highlight promising new therapies that have been or are currently being tested in clinical trials and discuss the molecular studies that can help identify the most suitable patients for these upcoming therapeutic approaches.

Changing vision: a review of pharmacogenetic studies for treatment response in age-related macular degeneration patients

Nonresponsiveness to age-related macular degeneration (AMD) treatments has become a growing concern in ophthalmology. Disparity among publications that have assessed pharmacogenetic (PGx) connections between AMD disease genes and treatments has delayed the implementation of PGx testing in AMD. We assessed all AMD PGx publications to identify the degree of agreement for publications within similar ethnic cohorts and worldwide, and the causes for differences in study outcomes. There are no accepted genotype–phenotype correlations, either within similar ethnic cohorts or worldwide. The diversity of measured outcomes, treatment protocols and statistical methods used may be causing this discrepancy. A universally accepted treatment protocol and the creation of agreed response group classification may bridge the gap between AMD PGx publications.

Towards the application of precision medicine in Age-Related Macular Degeneration

The review essentially describes genetic and non-genetic variables contributing to the onset and progression of exudative Age-related Macular Degeneration (AMD) in Italian population. In particular, AMD susceptibility within Italian population is contributed to by genetic variants, accounting for 23% of disease and non-genetic variants, accounting for 10% of AMD. Our data highlighted prominent differences concerning genetic and non-genetic contributors to AMD in our cohort with respect to worldwide populations. Among genetic variables, SNPs of CFH, ARMS2, IL-8, TIMP3, SLC16A8, RAD51B, VEGFA and COL8A1 were significantly associated with the risk of AMD in the Italian cohort. Surprisingly, other susceptibility variants described in European, American and Asiatic populations, did not reach the significance threshold in our cohort. As expected, advanced age, smoking and dietary habits were associated with the disease. In addition, we also describe a number of gene-gene and gene-phenotype interactions. In fact, AMD-associated genes may be involved in the alteration of Bruch's membrane and induction of angiogenesis, contributing to exacerbate the damage caused by aging and environmental factors. Our review provides an overview of genetic and non-genetic factors characterizing AMD susceptibility in Italian population, outlining the differences with respect to the worldwide populations. Altogether, these data reflect historical, geographic, demographic and lifestyle peculiarities of Italian population. The role of epigenetics, pharmacogenetics, comorbities and genetic counseling in the management of AMD patients have been described, in the perspective of the application of a "population-specific precision medicine" approach addressed to prevent AMD onset and improve patients' quality of life.

Retinal and choroidal angiogenesis: a review of new targets

Retinal and choroidal neovascularization are a major cause of significant visual impairment, worldwide. Understanding the various factors involved in the accompanying physiopathology is vital for development of novel treatments, and most important, for preserving patient vision. The intraocular use of anti-vascular endothelial growth factor therapeutics has improved management of the retinal and choroidal neovascularization but some patients do not respond, suggesting other vascular mediators may also contribute to ocular angiogenesis. Several recent studies examined possible new targets for future anti-angiogenic therapies. Potential targets of retinal and choroidal neovascularization therapy include members of the platelet-derived growth factor family, vascular endothelial growth factor sub-family, epidermal growth factor family, fibroblast growth factor family, transforming growth factor-β superfamily (TGF-β1, activins, follistatin and bone morphogenetic proteins), angiopoietin-like family, galectins family, integrin superfamily, as well as pigment epithelium derived factor, hepatocyte growth factor, angiopoietins, endothelins, hypoxia-inducible factors, insulin-like growth factors, cytokines, matrix metalloproteinases and their inhibitors and glycosylation proteins. This review highlights current antiangiogenic therapies under development, and discusses future retinal and choroidal pro- and anti-angiogenic targets as wells as the importance of developing of new drugs.

Regulation of the hypoxic tumor environment in hepatocellular carcinoma using RNA interference

OBJECTIVES

Hypoxia is the condition where tumor cells have been deprived of oxygen and has been shown to have a role of tumor development in the hepatocellular carcinoma (HCC).

METHODS

Using PubMed online database and Google scholar web site, the terms "angiogenesis", "apoptosis", "RNA interference" and/or "hepatocellular carcinoma (HCC)" were searched and analyzed.

RESULTS

The hypoxia inducible factors (HIFs) are transcriptional regulators that affect a homeostatic response to oxidative stress and have been identified as a key transcription activator of angiogenesis, survival, and metabolism. Cytokines, such as IL-8, also controlled endothelia cells survival and angiogenesis. IL-8 was also overexpressed under hypoxia and induced tumor angiogenesis and growth.

CONCLUSION

Therefore, regulation of HIFs and IL-8 controlled the tumor microenvironment in terms of tumor angiogenesis and apoptosis. The review summarizes the results of regulation of the hypoxic tumor environment.