Prognostic phenotypic and genotypic factors associated with photodynamic therapy response in patients with age-related macular degeneration

VEGFA Haplotype and VEGF-A and VEGF-R2 Protein Associations with Exudative Age-Related Macular Degeneration

Our study aimed to reveal the associations between VEGFA SNPs (rs1570360, rs699947, rs3025033, and rs2146323), their haplotypes, VEGF-A and VEGF-R2 serum concentrations, and early and exudative AMD. A total of 339 subjects with early AMD and 419 with exudative AMD groups, and 374 healthy subjects, were genotyped for four VEGFA SNPs (rs1570360, rs699947, rs3025033, and rs2146323). VEGF-A and VEGFR-2 serum concentrations were measured in exudative AMD and controls. The results revealed that rs3025033 G allele was significantly associated with lower odds of exudative AMD under the dominant model (OR = 0.67; 95% CI: 0.49–0.80; p = 0.0088) and additive (OR = 0.7; 95% CI: 0.54–0.90; p = 0.0058) models after Bonferroni correction. In the female group, rs3025033 AG genotype was associated with exudative AMD under the codominant model (OR = 0.57; 95% CI: 0.37–0.87; p = 0.009) and G allele under the dominant (OR = 0.55; 95% CI: 0.37–0.82; p = 0.0032) and additive models (OR = 0.60; 95% CI: 0.42–0.84; p = 0.0028). Haplotype analysis revealed that individuals carrying rs1570360, rs699947, rs3025033, and rs2146323 haplotype A-A-G-A had decreased risk of exudative AMD (OR = 0.46, 95% CI: 0.23–0.90; p = 0.023). The VEGF-A and VEGF-R2 serum concentrations did not differ between study groups; we found that patients with exudative AMD carrying at least one C allele at rs699947 have statistically significantly higher VEGF-A serum concentrations compared to AA genotype carriers (485.95 (945.93) vs. 194.97 (-), respectively, p = 0.046). In conclusion, we found that VEGFA rs3025033 and haplotype rs1570360A-rs699947A-rs3025033G- rs2146323A play a protective role for exudative AMD in the Caucasian population. Furthermore, rs699947 is associated with elevated VEGF-A serum concentrations in exudative AMD.

Impact of methylenetetrahydrofolate reductase C677T polymorphism on the efficacy of photodynamic therapy in patients with neovascular age-related macular degeneration

The most severe visual impairments due to age-related macular degeneration (AMD) are frequently caused by the occurrence of choroidal neovascularization (CNV). Although photodynamic therapy with verteporfin (PDT-V) is currently a second-line treatment for neovascular AMD, it can be conveniently combined with drugs acting against vascular endothelial growth factor (anti-VEGF) to reduce the healthcare burden associated with the growing necessity of anti-VEGF intravitreal re-injection. Because the common 677 C > T polymorphism of the methylenetetrahydrofolate reductase gene (MTHFR-C677T; rs1801133) has been described as predictor of satisfactory short-term responsiveness of AMD-related CNV to PDT-V, we retrospectively examined the outcomes of 371 Caucasian patients treated with standardized, pro-re-nata, photodynamic regimen for 24 months. Responder (R) and non-responder (NR) patients were distinguished on the basis of the total number of scheduled PDT-V (TN-PDT-V) and change of best-corrected visual acuity (∆-BCVA). The risk for both TN-PDT-V and ∆-BCVA to pass from R to NR group was strongly correlated with CT and TT genotypes of MTHFR-C677T variant resulting, respectively, in odd ratios of 0.19 [95% CI, 0.12-0.32] and 0.09 [95% CI, 0.04-0.21] (P < 0.001), and odd ratios of 0.24 [95% CI, 0.15-0.39] and 0.03 [95% CI, 0.01-0.11] (P < 0.001). These pharmacogenetic findings indicate a rational basis to optimize the future clinical application of PDT-V during the combined treatments of AMD-related CNV, highlighting the role of thrombophilia to be aware of the efficacy profile of photodynamic therapy.

Association between PEDF gene polymorphisms and the risk of age-related macular degeneration

OBJECTIVE

Pigment epithelium-derived factor (PEDF) strongly inhibits angiogenesis, and plays an important role in retinoblastoma cells. In this study we detect the association of PEDF gene polymorphisms (rs1136287 and rs12150053) and age-related macular degeneration (AMD) risk.

METHODS

This is a case-control study including 118 AMD patients and 121 healthy controls. PEDF gene polymorphisms were genotyped by TaqMan method. Hardy-Weinberg equilibrium (HWE) was used to detect the representativeness of the cases and controls. Differences of genotype and allele distributions of PEDF polymorphisms were calculated by Chi-square test. Odds ratios (ORs) and corresponding 95% confidence intervals (95% CIs) were used to present the relative risk of AMD.

RESULTS

Genotype and allele distributions in controls were in accordance with HWE. Genotype and allele distributions of rs1136287 had no significant association with the susceptibility of AMD under five contrast models (P<0.05). CC genotype and C allele of rs12150053 were higher in cases than that in controls, and rs12150053 was obviously related to the risk of AMD under T vs. C model (P=0.044, OR=1.499, 95% CI=1.009-2.226).

CONCLUSION

In this study, there was no obvious association between PEDF gene rs1136287 polymorphism and AMD susceptibility, and rs12150053T might act as a susceptible allele in the occurrence of AMD.

Mining the topography and dynamics of the 4D Nucleome to identify novel CNS drug pathways

The pharmacoepigenome can be defined as the active, noncoding province of the genome including canonical spatial and temporal regulatory mechanisms of gene regulation that respond to xenobiotic stimuli. Many psychotropic drugs that have been in clinical use for decades have ill-defined mechanisms of action that are beginning to be resolved as we understand the transcriptional hierarchy and dynamics of the nucleus. In this review, we describe spatial, temporal and biomechanical mechanisms mediated by psychotropic medications. Focus is placed on a bioinformatics pipeline that can be used both for detection of pharmacoepigenomic variants that discretize drug response and adverse events to improve pharmacogenomic testing, and for the discovery of novel CNS therapeutics. This approach integrates the functional topology and dynamics of the transcriptional hierarchy of the pharmacoepigenome, gene variant-driven identification of pharmacogenomic regulatory domains, and mesoscale mapping for the discovery of novel CNS pharmacodynamic pathways in human brain. Examples of the application of this pipeline are provided, including the discovery of valproic acid (VPA) mediated transcriptional reprogramming of neuronal cell fate following injury, and mapping of a CNS pathway glutamatergic pathway for the mood stabilizer lithium. These examples in regulatory pharmacoepigenomics illustrate how ongoing research using the 4D nucleome provides a foundation to further insight into previously unrecognized psychotropic drug pharmacodynamic pathways in the human CNS.

Age-related macular degeneration and polypoidal choroidal vasculopathy in Asians

Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in elderly people globally. It is estimated that there will be more Asians with AMD than the rest of the world combined by 2050. In Asian populations, polypoidal choroidal vasculopathy (PCV) is a common subtype of exudative AMD, while choroidal neovascularization secondary to AMD (CNV-AMD) is the typical subtype in Western populations. The two subtypes share many common clinical features and risk factors, but also have different epidemiological and clinical characteristics, natural history and treatment outcomes that point to distinct pathophysiological processes. Recent research in the fields of genetics, proteomics and imaging has provided further clarification of differences between PCV and CNV-AMD. Importantly, these differences have manifested as disparity in response to intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) treatment between PCV and CNV-AMD, emphasizing the need for accurate diagnosis of PCV and in distinguishing PCV from CNV-AMD, particularly in Asian patients. Current clinical trials of intravitreal anti-VEGF therapy and photodynamic therapy will provide clearer perspectives of evidence-based management of PCV and may lead to paradigm shifts in therapeutic strategies away from those currently employed in the treatment of CNV-AMD. Further research is needed to clarify the relative contribution of specific pathways in inflammation, complement activation, extracellular matrix dysregulation, lipid metabolism and angiogenesis to the pathogenesis of PCV. Findings from this research, together with improved diagnostic technology and new therapeutics, will facilitate more optimal management of Asian AMD.

Photodynamic therapy in VEGF inhibition non-responders-Pharmacogenetic study in age-related macular degeneration assessed with swept-source optical coherence tomography

BACKGROUND

Treatment of neovascular age-related macular degeneration (nAMD) remains a major challenge in ophthalmology. It is essential to determine which of VEGF inhibition non-responders can benefit from photodynamic therapy (PDT). As AMD is strongly related to gene polymorphisms, genetic factors can modify efficacy of treatment. Swept-source optical coherence tomography (SS-OCT) gives exceptional insight into the retina and choroid. SS-OCT usefulness needs to be evaluated in nAMD patients.

METHODS

Prospective 6-month study included consecutive 110 patients (110 eyes) with predominantly classic neovascular AMD treated with photodynamic therapy. Only non-responders to anti-VEGF were included in the study. Greatest linear dimension (GLD) of the lesion, best corrected visual acuity (BCVA), central subfield macular thickness (CSMT) and central choroidal thickness were assessed and compared between CFH and ARMS2 genotype groups. Success rate was the main endpoint. It was defined as not active CNV in the center of the fovea and no worsening in BCVA. Multiple regression was used to assess gene polymorphisms influence on PDT results. Wilcoxon tests were performed to determine significance of changes from baseline values.

RESULTS

Following genotype frequencies were obtained-CFH CC 35 patients (31.8%), CT 52 (47.3%), TT 23 (20.9%); ARMS2 TT 28 patients (25.4%), GT 43 (39.1%), GG 39 (35.4%) success rate in CC/CT/TT CFH and TT/GT/GG ARMS2 groups were as follows respectively: 22.9%, 28.8%, 30.4% and 28.6%, 25.6%, 28.2%. The differences were not significant with highest odds ratio TT vs. CC CFH 1.57 (95% CI 0.48-5.2, p=0.4). Significant increase in GLD was observed only in CC CFH group. Overall mean following measured parameters were obtained at baseline/day 7/month 3/month 6 (significant changes from baseline are marked with asterisk): GLD-3825±1301μm/3901±1579μm/3861±1463μm/3925±1523μm; CSMT-405±203μm/434±257μm*/321±163μm*/295±157*μm; CCT-235±103μm/278±157*μm/211±113μm*/201±107*μm; BCVA-49.3±12.5/43.2±14.2*/49.6±11.6/48.7±12.2 letters on ETDRS charts. In all patients classic component of the lesion was assessed with SS-OCT with no need to be reaffirmed in FA. Thus FA was used mainly for lesion size calculation.

CONCLUSIONS

Common genetic factors seem not to influence PDT effectiveness in VEGF inhibitors non-responders. SS-OCT is a valuable tool of nAMD monitoring, especially for choroid assessment. Deterioration of retinal structure and function is observed one week after PDT. It is related to increase in both retinal and choroidal thickness and is accompanied by mild temporary BCVA decrease.