PON1, APOE and SDF-1 Gene Polymorphisms and Risk of Retinal Vein Occlusion: A Case-Control Study

Numerous studies have tried to evaluate the potential role of thrombophilia-related genes in retinal vein occlusion (RVO); however, there is limited research on genes related to different pathophysiological mechanisms involved in RVO. In view of the strong contribution of oxidative stress and inflammation to the pathogenesis of RVO, the purpose of the present study was to investigate the association of inflammation- and oxidative-stress-related polymorphisms from three different genes [apolipoprotein E (APOE), paraoxonase 1 (PON1) and stromal cell-derived factor 1 (SDF-1)] and the risk of RVO in a Greek population. Participants in this case-control study were 50 RVO patients (RVO group) and 50 healthy volunteers (control group). Blood samples were collected on EDTA tubes and genomic DNA was extracted. Genotyping of rs854560 (L55M) and rs662 (Q192R) for the PON1 gene, rs429358 and rs7412 for the APOE gene and rs1801157 [SDF1-3'G(801)A] for SDF-1 gene was performed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Multiple genetic models (codominant, dominant, recessive, overdominant and log-additive) and haplotype analyses were performed using the SNPStats web tool to assess the correlation between the genetic polymorphisms and the risk of RVO. Binary logistic regression analysis was used for the association analysis between APOE gene variants and RVO. Given the multifactorial nature of the disease, our statistical analysis was adjusted for the most important systemic risk factors (age, hypertension and diabetes mellitus). The dominant genetic model for the PON1 Q192R single nucleotide polymorphism (SNP) of the association analysis revealed that there was a statistically significant difference between the RVO group and the control group. Specifically, after adjusting for age and hypertension, the PON1 192 R allele (QR + RR) was found to be associated with a statistically significantly higher risk of RVO compared to the QQ genotype (OR = 2.51; 95% CI = 1.02-6.14, p = 0.04). The statistically significant results were maintained after including diabetes in the multivariate model in addition to age and hypertension (OR = 2.83; 95% CI = 1.01-7.97, p = 0.042). No statistically significant association was revealed between the other studied polymorphisms and the risk of RVO. Haplotype analysis for PON1 SNPs, L55M and Q192R, revealed no statistically significant correlation. In conclusion, PON1 192 R allele carriers (QR + RR) were associated with a statistically significantly increased risk of RVO compared to the QQ homozygotes. These findings suggest that the R allele of the PON1 Q192R is likely to play a role as a risk factor for retinal vein occlusion.

Highlights on Genetic Polymorphism Associated with Thromboembolic Risk; Implications in Ophthalmic and Autoimmune Disorders—A Review

The present paper explores genetic polymorphism and its association with thromboembolic retinal venous disorders, such as central/hemi-retinal vein occlusion, as well as possible correlations with other ocular findings, such as closed angle glaucoma, but also with autoimmune general disorders. In this review, we are highlighting the importance of establishing a correspondence between all of the above, since they all have complex etiopathogeneses; sometimes, when all coexist together, they could generate effects that may be very difficult to manage. There are studies supporting that genetic polymorphism, such as the variant MTHFR A1298C, may increase the risk for developing glaucoma, especially in the heterozygote model. Being aware of all these aspects may prove to be useful in patients with several associated diseases, as a combined effort between several medical specialties may prove to the benefit of these patients. Our review, completed with an exemplifying clinical case, shows that it is necessary to raise awareness of all aspects of a complex medical situation, including the genetic one, of a patient being at risk for thromboembolic episodes, for preventing them or managing them promptly and properly in the future.

Role of Genetic Thrombophilia Markers in Thrombosis Events in Elderly Patients with COVID-19

Thrombosis is an extremely dangerous complication in elderly patients with COVID-19. Since the first months of the pandemic, anticoagulants have been mandatory in treatment protocols for patients with COVID-19, unless there are serious contraindications. We set out to discover if genetic thrombophilia factors continue to play a triggering role in the occurrence of thrombosis in patients with COVID-19 with prophylactic or therapeutic anticoagulants. We considered the following genetic markers as risk factors for thrombophilia: G1691A in the FV gene, C677T and A1298C in the MTHFR gene, G20210A and C494T in the FII gene, and (−675) 4G/5G in the PAI-I gene. In a cohort of 176 patients, we did not obtain a reliable result indicating a higher risk of thrombotic complications when taking therapeutic doses of anticoagulants in carriers of genetic markers for thrombophilia except the C494T mutation in the FII gene. However, there was still a pronounced tendency to a higher incidence of thrombosis in patients with markers of hereditary thrombophilia, such as FV G1691A and FII G20210A mutations. The presence of the C494T (Thr165Met) allele in the FII gene in this group of patients showed a statistically significant effect of the mutation on the risk of thrombotic complications despite anticoagulant therapy.

Methylenetetrahydrofolate reductase polymorphisms as risk factors for retinal venous occlusive disease: A literature review

The role of polymorphisms of methylenetetrahydrofolate reductase (MTHFR) gene in retinal vein occlusion (RVO) is a theme of discussion since the first reports of RVO in patients with MTHFR C677T mutation and without classic acquired risk factors for retinal vascular disease. The association between MTHFR polymorphisms and RVO has been studied over the last 20 years producing conflicting results. This review aims to summarize the literature concerning the role MTHFR polymorphisms as risk factors for RVO.

Correlation between PAI-1 rs1799889 polymorphism and venous thromboembolism: A meta-analysis of 48 case-control studies

BACKGROUND

We performed this meta-analysis to better assess the relationship between plasminogen activator inhibitor-1 (PAI-1) rs1799889 polymorphism and the risk of venous thromboembolism.

METHOD

Eligible studies were searched in PubMed, Medline, Embase, Web of Science and CNKI. Odds ratios with 95% confidence intervals were calculated.

RESULT

A total of 48 studies with 14,806 participants were analyzed. No positive results were detected in overall analyses. Further subgroup analyses revealed that the PAI-1 rs1799889 polymorphism was significantly associated with the risk of venous thromboembolism in Caucasians and East Asians. When we stratified available data according to type of disease, we found that the PAI-1 rs1799889 polymorphism was significantly correlated with the risk of DVT. No any other positive results were observed in overall and subgroup analyses.

CONCLUSION

Our findings indicate that the PAI-1 rs1799889 polymorphism may serve as a potential biological marker for venous thromboembolism in Caucasians and East Asians.

Thrombophilic risk factors for retinal vein occlusion

The aim is to study risk factors for retinal vein occlusion (RVO), such as thrombophilic and cardiovascular risk factors (CRF). A retrospective consecutive case series of 60 patients with RVO was made, tested for CRF, hyperhomocysteinemia, lupic anticoagulant, antiphospholipid antibody and 5 gene variants: factor V (FV) Leiden (G1691A), factor II (PT G20210A), 5,1-methylenetetra-hydrofolate reductase (MTHFR; 677 C > T and 1298 A > C), plasminogen activator inhibitor 1 (PAI-1; 4 G/5 G). More than 1 CRF were present in 36 patients (60%), which had a significantly higher mean age at diagnosis (66.7 ± 12.9 versus 59.5 ± 13.7 with ≤1 CRF, [t(57) = −2.05, p = 0.045, d = 0.54). Patients with thermolabile MTHFR forms with decreased enzyme activity (T677T or C677T/A1298C) had a significant lower mean age [57.6 ± 15.1; t (58) = 3.32; p = 0.002; d = 0.846] than patients with normal MTHFR enzyme activity (68.5 ± 10.2). Regarding CRF and thermolabile forms of MTHFR, the mean age at diagnosis could be significantly predicted [F(2,56) = 7.18; p = 0.002] by the equation: 64.8 − 10.3 × (thermolabile MTHFR) − 5.31 × ( ≤ 1CRF). Screening of MTHFR polymorphisms may be useful in younger RVO patients, particularly when multiple CRF are absent.

Genetic polymorphisms associated with the prevalence of retinal vein occlusion in a Greek population

PURPOSE

To investigate possible associations of single-nucleotide polymorphisms (SNPs) from five genes with branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO).

METHODS

A total of 69 patients with retinal vein occlusion-RVO (24 with BRVO and 45 with CRVO), and 82 controls, were enrolled in this study. All subjects were screened for hypertension, diabetes mellitus, hyperlipidemia, glaucoma, anticoagulant medication, smoking status and history of stroke. The genotyping of AGTR1-A1166C, adiponectin + 276 G/T, MMP2-1306C/T, Gpla/lla-C807T/G873A and VKORC1-G1639A polymorphisms was performed using restriction fragment length polymorphism or allele-specific polymerase chain reaction.

RESULTS

The percentage of the AGTR1-A1166C C allele carriers and Gpla/lla-C807T/G873A T/A carriers was significantly higher in the CRVO patients than in the controls (P = 0.00001 and P = 0.0004, respectively). At the multiple logistic regression analysis, the AGTR1-A1166C C allele carrier status and the Gpla/lla-C807T/G873A T/A allele carrier status were found to be associated with an increased risk of CRVO. Moreover, adiponectin + 276 G/T T allele carriers had a significantly increased risk of RVO in subjects ≥ 75 years old. There was no significant difference between the BRVO patients and controls concerning the genotype or the allele frequency distributions of these SNPs. The genotype distributions or allelic frequencies of the other evaluated polymorphisms did not significantly differ between the patients with RVO and the control subjects.

CONCLUSIONS

AGTR1 A1166C and Gpla/lla C807T/G873A polymorphisms are likely to be risk factors for CRVO. Adiponectin + 276 G/T SNP is likely to predispose to RVO in older subjects.

Can Rotational Thromboelastometry be a New Predictive Tool for Retinal Vein Occlusion Development?

PURPOSE

To evaluate clotting dynamics by a new tool called rotational tromboelastometry (ROTEM) in retinal vein occlusion.

MATERIALS AND METHODS

Thirty-six patients who were diagnosed with retinal vein occlusion and 43 age and sex matched healthy controls were included in this study. Diabetes and use of anticoagulant therapy were exclusion criteria. All study participants underwent detailed ophthalmologic and systemic medical examination, including blood pressure measurement, hemoglobin-hematocrit levels, platelet count, coagulation parameters including prothrombin time, activated partial thromboplastin time, fibrinogen levels, and D-dimer levels. Peripheral blood samples were collected and analyzed with ROTEM Coagulation Analyzer (Tem International, Munich, Germany).

RESULTS

The RVO patients and controls did not differ with respect to age, sex, hemoglobin, hematocrit, platelet numbers, prothrombin time, activated partial thromboplastin time, fibrinogen levels, D-dimer levels, and glucose levels. When extrinsic thromboelastometry results were analyzed, RVO patients showed a significantly decreased clotting time (76.5 ± 15.0 vs. 95.0 ± 21 s, respectively; p = 0.01) and clot formation time (83.3 ± 22 vs. 99.7 ± 24s; p = 0.01) as compared with healthy controls. Other ROTEM parameters did now show any difference between two groups.

CONCLUSION

Patients with retinal vein occlusion showed faster clotting time and shorter clotting formation time as compared with healthy controls. ROTEM detects the altered clotting dynamics and may be a useful tool to elucidate the disease pathophysiology. Further studies are needed to investigate if it can be used as a screening test for individuals who are under risk to develop RVO or as a first step test to evaluate hypercoagulable state in RVO.

Genetic Background of a Recurrent Unusual Combined Form of Retinal Vein Occlusion: A Case Report

The authors report a rare case of nonischemic branch retinal vein occlusion and nonischemic hemiretinal vein occlusion in a patient with impaired fibrinolysis. A 61-year-old woman presented to the Department of Ophthalmology, Clinical Hospital Center Split, Croatia, with acute blurring of vision in the right eye (RE) due to branch retinal vein occlusion. Ophthalmologic evaluation revealed a best corrected visual acuity (BCVA) of 0.02 in the RE and of 1.0 in the left eye. Ophthalmoscopy and fluorescein angiography of the RE demonstrated signs of nonischemic branch retinal vein occlusion. She was otherwise healthy and had no other ocular and systemic diseases. She was treated with 3 consecutive intravitreal applications of anti-vascular endothelial growth factor (anti-VEGF; bevacizumab) due to cystoid macular edema with full resolution of the intraretinal fluid and improvement of the BCVA to 0.9. After 8 months, she presented again with acute blurring of vision in the same (right) eye with a BCVA of 0.5. Ophthalmoscopy and fluorescein angiography of the RE indicated nonischemic hemiretinal vein occlusion. She was treated with a single intravitreal application of anti-VEGF (ranibizumab) due to macular edema. Full resolution of the intraretinal fluid and improvement of the BCVA to 0.9 were achieved. A laboratory workup was performed to rule out all known causes of retinal venous occlusive disease, which showed negative results. A molecular analysis showed the gen of thrombophilia – plasminogen activator inhibitor (PAI)-1 4G/5G polymorphism genotype – as the only risk factor for retinal venous occlusive disease in our patient.

Thrombophilic and cardiovascular risk factors for retinal vein occlusion

BACKGROUND

The role of thrombophilic and cardiovascular risk factors in different manifestations of retinal vein occlusion (RVO), i.e., central or branch RVO, and at different ages is still debated.

AIMS

To evaluate the association between thrombophilic and cardiovascular risk factors and the risk of RVO (overall, separately for central and branch RVO, and at different ages).

METHODS

Case-control study on 313 patients with a first objectively-confirmed RVO (216 central and 97 branch RVO) and 415 healthy individuals.

RESULTS

Antithrombin, protein C or protein S deficiency (adjusted odds ratio [95%CI]: 15.60 [2.01-121]; p=0.009), hyperhomocysteinemia (HHCy; 3.22 [1.38-7.49]; p=0.007), high factor VIII (FVIII) levels (3.08 [1.20-7.89]; p=0.019), factor V Leiden (2.93 [0.97-8.86]; p=0.058) and the presence of at least one cardiovascular risk factor (1.79 [1.00-3.23]; p=0.050) were associated with an increased risk of branch RVO. The association was weaker for central RVO, and limited to HHCy (2.15 [1.09-4.24]; p=0.027) and high FVIII (1.99 [0.90-4.42]; p=0.091). For HHCy, high FVIII and cardiovascular risk factors the association with the risk of RVO was stronger at an age>50years (3.41[1.29-8.99], p=0.013; 2.57[1.00-6.68], p=0.050; and 2.03[1.16-3.56], p=0.013, respectively) than ≤50years (1.93[0.85-4.36], p=0.114; 1.67[0.54-5.12], p=0.371; and 1.22[0.73-2.03], p=0.454, respectively), whereas classic inherited thrombophilia (antithrombin, protein C or protein S deficiencies, factor V Leiden and prothrombin G20210A mutation) was slightly more prevalent at an age≤50years (1.62 [0.76-3.45], p=0.210) than >50years (1.11[0.44-2.79], p=0.833).

CONCLUSIONS

Thrombophilic and cardiovascular risk factors are associated with RVO, particularly branch RVO. The risk of RVO associated with HHCy, high FVIII and cardiovascular risk factors is higher at an older age.

Preservation of retinal structure and function after cilioretinal artery occlusion: a case report

Cilioretinal artery occlusion is a cause of sudden, often catastrophic loss of central vision. There are no established effective treatments. Recently, a patient presented 24 hours after a cilioretinal artery occlusion, following a cardiac catheterization prior to which her blood thinners had been discontinued. Lacking an effective way to address the severe retinal ischemic oxidative stress, she was offered, under compassionate use, a multivitamin complex designed to address retinal ischemia and oxidative stress. Significant components of this product are L-methylfolate and n-acetyl cysteine. The patient experienced a rapid unexpected improvement in vision and preservation of retinal structure, suggesting that marked improvement in retinal artery occlusions outcomes may be possible as late as 24 hours postocclusion. This is the third reported case of cilioretinal artery occlusion associated with cardiac catheterization.

The role of coagulation disorders in patients with retinal vein occlusion

BACKGROUND

The role of a hypercoagulable state in the pathogenesis of retinal vein occlusion (RVO) has not been conclusively established.

AIM

To analyse the prevalence of thrombophilia in RVO.

DESIGN

Prospective case-control study.

METHODS

All the patients diagnosed with RVO were referred to an Internal Medicine clinic and compared with sex- and age-matched individuals from a population-based cohort. Demographic, clinical and laboratory variables (including a thrombophilia panel) were analysed.

RESULTS

One hundred and seventy patients (93 men and 77 women; 68 ± 11 years) and 170 controls (80 men and 90 women; 67 ± 10 years) were included. RVO was peripheral in 113 cases. Genetic thrombophilia was detected in 13% of patients. Acquired thrombophilia was observed in 10% of cases and 4.7 % of controls (P < 0.01). Sixty-three percent of cases and 24.6% of controls had serum hyperhomocysteinemia (odds ratio [OR] 5.2, IC 95% 2.7-10.1; P < 0.0001) : In RVO patients aged <50 years (n = 11), 36.4% had genetic thrombophilia (P = 0.04), as well as 50% of those without vascular risk factors (n = 18; P = 0.01). Forty-one (24%) patients with RVO received antiplatelet agents and 13 (7.6%) were on anticoagulants due to preexistent atrial fibrillation.

CONCLUSIONS

We suggest that, in patients with RVO, hyperhomocysteinemia and antiphospholipid syndrome should be ruled out. Moreover, a study of genetic thrombophilia should only be considered in those aged <50 years or without cardiovascular risk factors. Antiplatelet therapy with aspirin is probably the treatment of choice of RVO, to reduce the overall vascular risk. Anticoagulation should only be considered in patients with high-risk thrombophilia.

Association between the prothrombin G20210A mutation and sudden sensorineural hearing loss in European population: a meta-analysis

PURPOSE

Epidemiological studies have reported inconsistent findings on the association between the prothrombin G20210A mutation and sudden sensorineural hearing loss (SSNHL) in European population. The aim of this meta-analysis was to clarify the association of this polymorphism with SSNHL in European population.

METHODS

PubMed, Embase, and the China National Knowledge Infrastructure (CNKI) were searched up to August 1, 2014. We used STATA12.0 to calculate summary odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

Eight studies including 1972 patients were identified. Pooled data showed no significant association between the prothrombin G20210A mutation and risk of SSNHL in European population : A vs. G (OR =1.645, 95% CI:0.78-3.49,POR =0.194); AG vs.GG (OR =1.660, 95% CI:0.77-3.60,POR=0.199).

CONCLUSIONS

The present meta-analysis suggests that the prothrombin G20210A mutation is not significantly associated with an increased risk of SSNHL in European population.

Homocysteine, methylenetetrahydrofolate reductase C677T polymorphism, and risk of retinal vein occlusion: an updated meta-analysis

Background

To evaluate the role of plasma total homocysteine (tHcy) and homozygosity for the thermolabile variant of the methylenetetrahydrofolate reductase (MTHFR) C677T genotype in the risk of retinal vein occlusion (RVO).

Methods

Relevant studies were selected through an extensive search of PubMed, EMBASE, and the Web of Science databases. Summary weighted mean differences (WMDs) or odds ratios (ORs) and 95% confidence intervals (CI) were calculated with a random-effects model.

Results

Forty-two studies with 6445 participants were included in this updated systematic review and meta-analysis. The mean plasma tHcy level in the RVO patients was significantly higher than in the controls (WMD =2.13 μmol/L; 95% CI: 1.29 to 2.98, P < 0.001), but there was evidence of between-study heterogeneity (P < 0.001). No significant association between MTHFR C677T genotype and RVO was found under all genetic models.

Conclusion

There was some evidence that plasma tHcy is associated with an increased risk of RVO. There was no evidence to suggest an association between homozygosity for the MTHFR C677T genotype and RVO.

Relationship between angiotensin I-converting enzyme insertion/deletion gene polymorphism and retinal vein occlusion

To evaluate the association between angiotensin I-converting enzyme insertion/deletion (ACE I/D) gene polymorphism and retinal vein occlusion (RVO). A total of 80 patients with retinal vein occlusion who was admitted to the Eye Department of Kartal Training and Research Hospital between 2008 and 2011, and 80 subjects were enrolled in this retrospective case–control study. Patients who experienced RVO within one week to six months of study enrolment were included, and those with coronary artery diseases, prior myocardial infarction history and coagulation disturbances were excluded from the study. The diagnosis was made by ophthalmoscopic fundus examination and fluorescein angiography. The ACE gene I/D polymorphism was determined by polymerase chain reaction, and the ACE gene was classified into three types: I/I, I/D and D/D. In multivariate logistic regression analysis, ACE D/D genotype (p = 0.035), diabetes-mellitus (p = 0.019) and hypertension (p = 0.001) were found to be independent predictive factors for RVO. The results of the present study reveal that ACE D/D polymorphism is an independent predictive factor for RVO. However, one cannot definitely conclude that ACE gene polymorphism is a risk factor for retinal vein occlusion.