Analysis of complement factor H Y402H, LOC387715, HTRA1 polymorphisms and ApoE alleles with susceptibility to age-related macular degeneration in Hungarian patients

Non-Neovascular Age-Related Macular Degeneration Assessment: Focus on Optical Coherence Tomography Biomarkers

The imagistic evaluation of non-neovascular age-related macular degeneration (AMD) is crucial for diagnosis, monitoring progression, and guiding management of the disease. Dry AMD, characterized primarily by the presence of drusen and retinal pigment epithelium atrophy, requires detailed visualization of the retinal structure to assess its severity and progression. Several imaging modalities are pivotal in the evaluation of non-neovascular AMD, including optical coherence tomography, fundus autofluorescence, or color fundus photography. In the context of emerging therapies for geographic atrophy, like pegcetacoplan, it is critical to establish the baseline status of the disease, monitor the development and expansion of geographic atrophy, and to evaluate the retina's response to potential treatments in clinical trials. The present review, while initially providing a comprehensive description of the pathophysiology involved in AMD, aims to offer an overview of the imaging modalities employed in the evaluation of non-neovascular AMD. Special emphasis is placed on the assessment of progression biomarkers as discerned through optical coherence tomography. As the landscape of AMD treatment continues to evolve, advanced imaging techniques will remain at the forefront, enabling clinicians to offer the most effective and tailored treatments to their patients.

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.

The association study of lipid metabolism gene polymorphisms with AMD identifies a protective role for APOE-E2 allele in the wet form in a Northern Spanish population

PURPOSE

To elucidate the potential role of eleven single nucleotide polymorphisms (SNPs) in the most relevant lipid metabolism genes in Northern Spanish patients with age-related macular degeneration (AMD).

METHODS

A case-control study of 228 unrelated native Northern Spanish patients diagnosed with AMD (73 dry and 155 wet) and 95 healthy controls was performed. DNA was isolated from peripheral blood and genotyped for the SNPs APOE rs429358 and rs7412; CTEP rs3764261; LIPC rs10468017 and rs493258; LPL rs12678919; ABCA1 rs1883025; ABCA4 rs76157638, rs3112831 and rs1800555; and SCARB1 rs5888, using TaqMan probes. An additional association study of ε2, ε3 and ε4 major isoforms of APOE gene with AMD has been carried out.

RESULTS

The allele and genotype frequencies for each of the eleven sequence variants in the lipid metabolism genes did not show significant differences when comparing AMD cases and controls. Statistical analysis revealed that APOE-ε2 carrier genotypes were less frequently observed in patients with wet AMD compared to controls (5.8% versus 13.7%, respectively: p = 3.28 × 10^-2 ; OR = 0.42, 95% CI: 0.19-0.95). The frequency of the allele T of rs10468017 (LIPC gene) was lower in dry AMD cases compared to controls (15.8 versus 27.9%, respectively: p = 8.4 × 10^-3 OR = 0.57, 95% CI: 0.33-0.98).

CONCLUSIONS

Our results suggest a protective role for APOE-ε2 allele to wet AMD in the Northern Spanish population.

The association between complement factor H rs1061170 polymorphism and age-related macular degeneration: a comprehensive meta-analysis stratified by stage of disease and ethnicity

PURPOSE

The strength of association between complement factor H (CFH) rs1061170 polymorphism and age-related macular degeneration (AMD) differs between AMD subtypes and ethnicities. The main aim was to provide a systematic review and an updated meta-analysis stratified by stage of disease and ethnicity.

METHODS

A literature search in the PubMed-Medline, EMBASE and Web of Science databases was conducted to identify epidemiological studies, published before September 2017, that included at least twp comparison groups (a control group with no signs of AMD and a case group of AMD patients). Genotype distribution, phenotype of the cases, ethnicity, mean age and gender ratio were collected. Odds ratios (ORs) and 95%CIs were estimated under the allelic, homozygous and heterozygous models. Sensitivity and subgroup analyses, by AMD subtype and ethnicity, were performed.

RESULTS

The meta-analysis included data of 27 418 AMD patients and 32 843 controls from 76 studies. In Caucasians, the rs1061170 showed a significant association with early AMD (OR: 1.44; 95%CI 1.27-1.63), dry AMD (OR: 2.90; 95%CI 1.89-4.47) and wet AMD (OR: 2.46; 95%CI 2.15-2.83), under an allelic model. In Asians, the rs1061170 showed a significant association with advanced AMD (OR: 2.09; 95%CI 1.67-2.60), especially wet AMD (OR: 2.24; 95%CI 1.81-2.77).

CONCLUSION

Our work provides a more comprehensive meta-analysis of studies investigating the effect of the CFH rs1061170 polymorphism on AMD risk. These findings not only improve the assessment of disease risk associated with the polymorphism, but also constitute a scientific background to be translated into clinical practice for AMD prevention.

Association of Apolipoprotein E Polymorphisms with Age-related Macular Degeneration Subtypes: An Updated Systematic Review and Meta-analysis

BACKGROUND AND AIMS

Age-related macular degeneration (AMD) is the worldwide leading cause of blindness among the elderly, especially in developed countries. The possible association between apolipoprotein E (ApoE) polymorphism (ε2, ε3, ε4) and AMD has been extensively investigated with conflicting results, especially when specifying different clinical phenotypes of AMD. Herein, we conducted a meta-analysis by integrating several recent large-sample studies to verify the effect of ApoE polymorphisms on AMD subtypes.

METHODS

The retrieve for targeted literature was conducted based on the PubMed, Embase, Cochrane library, and Web of Science. Summary odds ratio (OR) and its 95% confidence intervals (CIs) were used for estimation of risk. The p-value was adjusted due to the multiple comparison.

RESULTS

A total of 12 studies included in the final summary analysis, including 13842 cases and 38647 controls. ApoE ε4 carrier was inversely associated with early stage AMD (OR = 0.889, 95% CI = 0.82-0.97), geographic atrophy (OR = 0.594, 95% CI = 0.43-0.83) and neovascular AMD (OR = 0.670, 95% CI = 0.58-0.76). Stratification analysis by ethnicity revealed that the ApoE ε4 carriers was associated with neovascular AMD in both Caucasians (OR = 0.62, 95% CI = 0.47-0.83) and East Asians (OR = 0.68, 95% CI = 0.58-0.79). A significant association of ApoE ε2 carriers was only found with early AMD in Black and East Asian population, however small samples and limited studies restrict its generalization.

CONCLUSION

Our meta-analysis revealed a significantly protective role of ε4 on each subtypes of AMD, but no supportive evidence of the association of ε2 with AMD. Thus, further studies with larger samples are needed to understand the precise role of ε2 on AMD susceptibility.

Association of Combined Complement Factor H Y402H and ARMS/LOC387715 A69S Polymorphisms with Age-related Macular Degeneration: A Meta-analysis

PURPOSE

Complement factor H (CFH) Y402H (rs1061170) and age-related maculopathy susceptibility2 (ARMS2)/LOC387715 A69S (rs10490924) polymorphisms shown to have significant association with age-related macular degeneration (AMD). In this meta-analysis, we pooled the results of the available association studies between combined ARMS2/LOC387715A69S-CFHY402H genotypes and AMD to estimate the possible synergistic or multiplicative effects.

METHODS

Heterogeneity of studies was evaluated using the Cochran Q-test and the 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 relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP), synergy index (S), and multiplicative index (V).

RESULTS

We included eight studies with 2915 AMD patients and 3505 control subjects. Considering the GGTT genotypes as reference lines, the pooled AMD Odds Ratios for stratified combined genotypes were 2.32 (95% CI 1.64-3.28) for GGnon-TT, 2.49 (95% CI 1.72-3.60) for non-GGTT, and 7.82 (95% CI 5.09-12.00) for non-GGnon-TT. Pooled synergy analysis revealed RERI = 4.08 (95% CI 3.15-5.27), AP = 0.50 (95% CI 0.42-0.57), S = 2.31 (95% CI 1.9-2.82), and V = 1.21 (95% CI 0.93-1.49).

CONCLUSION

This analysis revealed the synergistic and positive multiplicative effect of these two genes indicating that there is a common pathway of ARMS2/LOC387715 and CFH in AMD pathogenesis which may be the complement system pathway.

CFH polymorphisms in a Northern Spanish population with neovascular and dry forms of age-related macular degeneration

PURPOSE

To elucidate the potential role of single-nucleotide polymorphisms (SNPs) in complement factor H (CFH) gene in Northern Spanish patients with age-related macular degeneration (AMD).

METHODS

A case-control study of 130 unrelated native Northern Spanish diagnosed with AMD (46 dry, 35 neovascular and 49 mixed) and 96 healthy controls matched by age and ethnicity were enrolled. DNA was isolated from peripheral blood and genotyped for AMD-associated SNPs (rs3753394, rs529825, rs800292, rs3766404, rs203674, rs10671170, rs3753396 and rs1065489) using TaqMan probes and restriction fragment length polymorphism (RFLP). The association study was performed using the HaploView 4.0 software.

RESULTS

The allelic frequency analysis revealed that rs529825, rs800292, rs203674 and rs10671170 were significantly associated with an increased risk for AMD. The haplotypes CGG (rs3753394, rs529825 and rs800292) and GCAG (rs203674, rs1061170, rs3753396 and rs1065489) were significantly associated with AMD while the haplotypes CAA (rs3753394, rs529825 and rs800292) and TTAG (rs203674, rs1061170, rs3753396 and rs1065489) were found to be protective. Small differ-ences in allelic frequencies were found between dry and neovascular cases; however, these differences were not significant and did not distinguish one form the other.

CONCLUSIONS

This study found significant association of SNPs rs529825, rs800292, rs203674 and rs1061170 in the CFH gene with susceptibility to AMD. We identified haplotypes that confer protection or increased risk of AMD but not specific genetic variants in CFH capable to distinguish the different clinical forms of AMD in this cohort. Collectively, our results confirmed that CFH represents a strong genetic risk factor for this disease in the Northern Spanish population.

Activation of the UPR protects against cigarette smoke-induced RPE apoptosis through up-regulation of Nrf2

Recent studies have revealed a role of endoplasmic reticulum (ER) stress-induced unfolded protein response (UPR) in the regulation of RPE cell activity and survival. Herein, we examined the mechanisms by which the UPR modulates apoptotic signaling in human RPE cells challenged with cigarette smoking extract (CSE). Our results show that CSE exposure induced a dose- and time-dependent increase in ER stress markers, enhanced reactive oxygen species (ROS), mitochondrial fragmentation, and apoptosis of RPE cells. These changes were prevented by the anti-oxidant NAC or chemical chaperone TMAO, suggesting a close interaction between oxidative and ER stress in CSE-induced apoptosis. To decipher the role of the UPR, overexpression or down-regulation of XBP1 and CHOP genes was manipulated by adenovirus or siRNA. Overexpressing XBP1 protected against CSE-induced apoptosis by reducing CHOP, p-p38, and caspase-3 activation. In contrast, XBP1 knockdown sensitized the cells to CSE-induced apoptosis, which is likely through a CHOP-independent pathway. Surprisingly, knockdown of CHOP reduced p-eIF2α and Nrf2 resulting in a marked increase in caspase-3 activation and apoptosis. Furthermore, Nrf2 inhibition increased ER stress and exacerbated cell apoptosis, while Nrf2 overexpression reduced CHOP and protected RPE cells. Our data suggest that although CHOP may function as a pro-apoptotic gene during ER stress, it is also required for Nrf2 up-regulation and RPE cell survival. In addition, enhancing Nrf2 and XBP1 activity may help reduce oxidative and ER stress and protect RPE cells from cigarette smoke-induced damage.

Identification of genome-wide SNP-SNP and SNP-clinical Boolean interactions in age-related macular degeneration

We propose here a methodology to uncover modularities in the network of SNP-SNP interactions most associated with disease. We start by computing all possible Boolean binary SNP interactions across the whole genome. By constructing a weighted graph of the most relevant interactions and via a combinatorial optimization approach, we find the most highly interconnected SNPs. We show that the method can be easily extended to find SNP/environment interactions. Using a modestly sized GWAS dataset of age-related macular degeneration (AMD), we identify a group of only 19 SNPs, which include those in previously reported regions associated to AMD. We also uncover a larger set of loci pointing to a matrix of key processes and functions that are affected. The proposed integrative methodology extends and overlaps traditional statistical analysis in a natural way. Combinatorial optimization techniques allow us to find the kernel of the most central interactions, complementing current methods of GWAS analysis and also enhancing the search for gene-environment interaction.

Effect of the Gas6 c.834+7G>A polymorphism and the interaction of known risk factors on AMD pathogenesis in Hungarian patients

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly in the developed world. Numerous genetic factors contribute to the development of the multifactorial disease. We performed a case-control study to assess the risk conferred by known and candidate genetic polymorphisms on the development of AMD. We searched for genetic interactions and for differences in dry and wet AMD etiology. We enrolled 213 patients with exudative, 67 patients with dry AMD and 106 age and ethnically matched controls. Altogether 12 polymorphisms in Apolipoprotein E, complement factor H, complement factor I, complement component 3, blood coagulation factor XIII, HTRA1, LOC387715, Gas6 and MerTK genes were tested. No association was found between either the exudative or the dry form and the polymorphisms in the Apolipoprotein E, complement factor I, FXIII and MerTK genes. Gas6 c.834+7G>A polymorphism was found to be significantly protective irrespective of other genotypes, reducing the odds of wet type AMD by a half (OR = 0.50, 95%CI: 0.26–0.97, p = 0.04). Multiple regression models revealed an interesting genetic interaction in the dry AMD subgroup. In the absence of C3 risk allele, mutant genotypes of both CFH and HTRA1 behaved as strongly significant risk factors (OR = 7.96, 95%CI: 2.39 = 26.50, p = 0.0007, and OR = 36.02, 95%CI: 3.30–393.02, p = 0.0033, respectively), but reduced to neutrality otherwise. The risk allele of C3 was observed to carry a significant risk in the simultaneous absence of homozygous CFH and HTRA1 polymorphisms only, in which case it was associated with a near-five-fold relative increase in the odds of dry type AMD (OR = 4.93, 95%CI: 1.98–12.25, p = 0.0006). Our results suggest a protective role of Gas6 c.834+7G>A polymorphism in exudative AMD development. In addition, novel genetic interactions were revealed between CFH, HTRA1 and C3 polymorphisms that might contribute to the pathogenesis of dry AMD.

Genetic factors associated with age-related macular degeneration

Age-related macular degeneration (AMD) is a complex, multifactorial disease associated with environmental and genetic factors. This review emphasizes the clinical impact of the major genetic factors mainly located in the complement factor H gene and on the 10q26 locus, and their current and future implications for the management of AMD.

Association of variants in the LIPC and ABCA1 genes with intermediate and large drusen and advanced age-related macular degeneration

PURPOSE

Intermediate and large drusen usually precede advanced age-related macular degeneration (AMD). There is little information about which genes influence drusen accumulation. Discovery of genetic variants associated with drusen may lead to prevention and treatments of AMD in its early stages.

METHODS

A total of 3066 subjects were evaluated on the basis of ocular examinations and fundus photography and categorized as control (n = 221), intermediate drusen (n = 814), large drusen (n = 949), or advanced AMD (n = 1082). SNPs in the previously identified CFH, C2, C3, CFB, CFI, APOE, and ARMS2/HTRA1 genes/regions and the novel genes LIPC, CETP, and ABCA1 in the high-density lipoprotein (HDL) cholesterol pathway were genotyped. Associations between stage of AMD and SNPs were assessed using logistic regression.

RESULTS

Controlling for age, sex, education, smoking, body mass index, and antioxidant treatment, the number of minor (T) alleles of the genes LIPC and ABCA1 were significantly associated with a reduced risk of intermediate drusen (LIPC [P trend = 0.045], ABCA1 [P = 4.4 × 10(-3)]), large drusen (LIPC [P = 0.041], ABCA1 [P = 7.7 × 10(-4)]), and advanced AMD (LIPC [P = 1.8 × 10(-3)], ABCA1 [P = 3 × 10(-4)]). After further adjustment for known genetic factors, the protective effect of the TT genotype was significant for intermediate drusen (LIPC [odds ratio (OR), 0.56; 95% confidence interval (CI), 0.33-0.94], ABCA1 [OR, 0.48; 95% CI, 0.27-0.85]), large drusen (LIPC [OR, 0.58; 95% CI, 0.34-0.98)], ABCA1 [OR, 0.41; 95% CI, 0.23-0.74)]), and advanced AMD (LIPC [OR, 0.39; 95% CI, 0.21-0.74)], ABCA1 [OR, 0.35; 95% CI, 0.17-0.71)]). CFH, C3, C2, and ARMS2/HTRA1 were associated with large drusen and advanced AMD.

CONCLUSIONS

LIPC and ABCA1 are related to intermediate and large drusen, as well as advanced AMD. CFH, C3, C2, and ARMS2/HTRA1 are associated with large drusen and advanced AMD. Genes may have varying effects on different stages of AMD.

Genetics of age-related macular degeneration: current concepts, future directions

Age-related macular degeneration (AMD) is a progressive degenerative disease which leads to blindness, affecting the quality of life of millions of Americans. More than 1.75 million individuals in the United States are affected by the advanced form of AMD. The etiological pathway of AMD is not yet fully understood, but there is a clear genetic influence on disease risk. To date, the 1q32 (CFH) and 10q26 (PLEKHA1/ARMS2/HTRA1) loci are the most strongly associated with disease; however, the variation in these genomic regions alone is unable to predict disease development with high accuracy. Therefore, current genetic studies are aimed at identifying new genes associated with AMD and their modifiers, with the goal of discovering diagnostic or prognostic biomarkers. Moreover, these studies provide the foundation for further investigation into the pathophysiology of AMD by utilizing a systems-biology-based approach to elucidate underlying mechanistic pathways.