Association of combined cigarette smoking and ARMS2/LOC387715 A69S polymorphisms with age-related macular degeneration: A meta-analysis

10q26 - The enigma in age-related macular degeneration

Despite comprehensive research efforts over the last decades, the pathomechanisms of age-related macular degeneration (AMD) remain far from being understood. Large-scale genome wide association studies (GWAS) were able to provide a defined set of genetic aberrations which contribute to disease risk, with the strongest contributors mapping to distinct regions on chromosome 1 and 10. While the chromosome 1 locus comprises factors of the complement system with well-known functions, the role of the 10q26-locus in AMD-pathophysiology remains enigmatic. 10q26 harbors a cluster of three functional genes, namely PLEKHA1, ARMS2 and HTRA1, with most of the AMD-associated genetic variants mapping to the latter two genes. High linkage disequilibrium between ARMS2 and HTRA1 has kept association studies from reliably defining the risk-causing gene for long and only very recently the genetic risk region has been narrowed to ARMS2, suggesting that this is the true AMD gene at this locus. However, genetic associations alone do not suffice to prove causality and one or more of the 14 SNPs on this haplotype may be involved in long-range control of gene expression, leaving HTRA1 and PLEKHA1 still suspects in the pathogenic pathway. Both, ARMS2 and HTRA1 have been linked to extracellular matrix homeostasis, yet their exact molecular function as well as their role in AMD pathogenesis remains to be uncovered. The transcriptional regulation of the 10q26 locus adds an additional level of complexity, given, that gene-regulatory as well as epigenetic alterations may influence expression levels from 10q26 in diseased individuals. Here, we provide a comprehensive overview on the 10q26 locus and its three gene products on various levels of biological complexity and discuss current and future research strategies to shed light on one of the remaining enigmatic spots in the AMD landscape.

HTRA1 rs11200638 variant and AMD risk from a comprehensive analysis about 15,316 subjects

BACKGROUND

The high-temperature requirement factor A1 (HTRA1) gene located at 10q26 locus has been associated with age-related macular degenerative (AMD), with the significantly related polymorphism being (rs11200638, -625G/A), however, above association is not consistent. We investigated a comprehensive analysis to evaluate the correlations between rs11200638 polymorphism and AMD susceptibility thoroughly addressing this issue.

METHODS

An identification was covered from the PubMed and Wanfang databases until 27th Jan, 2020. Odds ratios (OR) with 95% confidence intervals (CI) were applied to evaluate the associations. After a thorough and meticulous search, 35 different articles (33 case-control studies with HWE, 22 case-control studies about wet/dry AMD) were retrieved.

RESULTS

Individuals carrying A-allele or AA genotype may have an increased risk to be AMD disease. For example, there has a significantly increased relationship between rs11200638 polymorphism and AMD both for Asians (OR: 2.51, 95%CI: 2.22-2.83 for allelic contrast) and Caucasians [OR (95%CI) = 2.63(2.29-3.02) for allelic contrast]. Moreover, a similar trend in the source of control was detected. To classify the type of AMD, increased association was also observed in both wet (OR: 3.40, 95%CI: 2.90-3.99 for dominant model) and dry (OR: 2.08, 95%CI: 1.24-3.48 for dominant model) AMD. Finally, based on the different genotyping methods, increased relationships were identified by sequencing, TaqMan, PCR-RFLP and RT-PCR.

CONCLUSIONS

Our meta-analysis demonstrated that HTRA1 rs11200638 polymorphism may be related to the AMD development, especially about individuals carrying A-allele or AA genotype, who may be as identified targets to detect and intervene in advance. Further studies using Larger sample size studies, including information about gene-environment interactions will be necessary to carry out.

Association of combined complement factor H Y402H and ARMS2/LOC387715 A69S polymorphisms with age-related macular degeneration: an updated meta-analysis

BACKGROUND

Complement factor H (CFH) Y402 H (rs1061170) and age-related maculopathy susceptibility2 (ARMS2)/LOC387715 A69 S (rs10490924) polymorphisms shown to have significant association with AMD. In this meta-analysis, we updated and pooled the results of available association studies between combined ARMS2/LOC387715A69 S-CFHY402 H genotypes and AMD to estimate the synergistic effects.

METHODS

Heterogeneity of studies was evaluated using Cochran Q-test and I-square index. To modify the heterogeneity in the variables we used random effects model. Meta-analysis was performed using STATA. To estimate the additive or supra-additive effects we calculated RERI (relative excess risk due to interaction), AP (attributable proportion due to interaction), S (synergy index) and V (multiplicative index).

RESULTS

We included 12 studies with 4668 AMD patients and 4936 control subjects. Considering the GGTT genotypes as reference line, the pooled AMD odds ratios for stratified combined genotypes was 2.13 (95% CI 1.64-2.78) for GGnonTT, 2.17 (95% CI 1.63-2.89) for nonGGTT and 7.23 (95% CI 4.95-10.55) for nonGGnonTT. Pooled synergy analysis revealed RERI = 3.90 (95% CI 0.58-10.03), AP = .53 (95% CI 0.09-0.69), S = 2.57 (95% CI 1.27-5.22) and V = 1.47 (95% CI 1.21-1.80).

CONCLUSION

This updated analysis showed a strong synergistic and positive multiplicative effect of these two genes indicating that there is common pathway of ARMS2/LOC387715 A69 S and CFH Y402 H in AMD pathogenesis which may be complement system pathway.

Anti-VEGF Treatment and Response in Age-related Macular Degeneration: Disease's Susceptibility, Pharmacogenetics and Pharmacokinetics

The current review is focussing different factors that contribute and directly correlate to the onset and progression of Age-related Macular Degeneration (AMD). In particular, the susceptibility to AMD due to genetic and non-genetic factors and the establishment of risk scores, based on the analysis of different genes to measure the risk of developing the disease. A correlation with the actual therapeutic landscape to treat AMD patients from the point of view of pharmacokinetics and pharmacogenetics is also exposed. Treatments commonly used, as well as different regimes of administration, will be especially important in trying to classify individuals as "responders" and "non-responders". Analysis of different genes correlated with drug response and also the emerging field of microRNAs (miRNAs) as possible biomarkers for early AMD detection and response will be also reviewed. This article aims to provide the reader a review of different publications correlated with AMD from the molecular and kinetic point of view as well as its commonly used treatments, major pitfalls and future directions that, to our knowledge, could be interesting to assess and follow in order to develop a personalized medicine model for AMD.

Microvascular contributions to age-related macular degeneration (AMD): from mechanisms of choriocapillaris aging to novel interventions

Aging of the microcirculatory network plays a central role in the pathogenesis of a wide range of age-related diseases, from heart failure to Alzheimer's disease. In the eye, changes in the choroid and choroidal microcirculation (choriocapillaris) also occur with age, and these changes can play a critical role in the pathogenesis of age-related macular degeneration (AMD). In order to develop novel treatments for amelioration of choriocapillaris aging and prevention of AMD, it is essential to understand the cellular and functional changes that occur in the choroid and choriocapillaris during aging. In this review, recent advances in in vivo analysis of choroidal structure and function in AMD patients and patients at risk for AMD are discussed. The pathophysiological roles of fundamental cellular and molecular mechanisms of aging including oxidative stress, mitochondrial dysfunction, and impaired resistance to molecular stressors in the choriocapillaris are also considered in terms of their contribution to the pathogenesis of AMD. The pathogenic roles of cardiovascular risk factors that exacerbate microvascular aging processes, such as smoking, hypertension, and obesity as they relate to AMD and choroid and choriocapillaris changes in patients with these cardiovascular risk factors, are also discussed. Finally, future directions and opportunities to develop novel interventions to prevent/delay AMD by targeting fundamental cellular and molecular aging processes are presented.

Estimating the Relative Excess Risk Due to Interaction in Clustered-Data Settings

The risk difference scale is often of primary interest when evaluating public health impacts of interventions on binary outcomes. However, few investigators report findings in terms of additive interaction, probably because the models typically used for binary outcomes implicitly measure interaction on the multiplicative scale. One measure with which to assess additive interaction from multiplicative models is the relative excess risk due to interaction (RERI). The RERI measure has been applied in many contexts, but one limitation of previous approaches is that clustering in data has rarely been considered. We evaluated the RERI metric for the setting of clustered data using both population-averaged and cluster-conditional models. In simulation studies, we found that estimation and inference for the RERI using population-averaged models was straightforward. However, frequentist implementations of cluster-conditional models including random intercepts often failed to converge or produced degenerate variance estimates. We developed a Bayesian implementation of log binomial random-intercept models, which represents an attractive alternative for estimating the RERI in cluster-conditional models. We applied the methods to an observational study of adverse birth outcomes in mothers with human immunodeficiency virus, in which mothers were clustered within clinical research sites.