Regulatory SNPs Alter the Gene Expression of Diabetic Retinopathy Associated Secretary Factors

Genetic Variability in VEGFA Gene Influences the Effectiveness of Tennis Elbow Therapy with PRP: A Two-Year Prospective Cohort Study

Vascular endothelial growth factor (VEGF) is implicated in both the etiology of tendinopathy and its healing process. Polymorphic variants of the VEGFA gene exhibit varied expression, which can influence the phenotype and treatment effectiveness. The aim of the present study was to analyze the influence of VEGFA gene variants on the effectiveness of tennis elbow therapy using platelet-rich plasma (PRP), measured through common patient-reported outcome measures (PROMs). A cohort of 107 patients (132 elbows) with tennis elbow was prospectively analyzed, with a two-year follow-up (at weeks 2, 4, 8, 12, 24, 52, and 104 after PRP injection). PROMs values were compared between variants of five VEGFA gene polymorphisms (rs699947 A>C, rs2010963 C>G, rs1413711 C>T, rs3024998 C>T and rs3025021 C>T) at each follow-up point. Patients with genotypes GG (rs2010963) and CC (rs3024998) had better response to PRP therapy (significantly fewer symptoms and limitations in the upper limb compared to carriers of alleles C and T, respectively). Polymorphisms influenced also selected hematological parameters. VEGFA gene polymorphisms (rs2010963 and rs3024998) appear to be significant treatment modifiers for tendinopathy, and their genotyping may serve as an effective tool for personalized patient selection for PRP therapy.

Intraretinal Microvascular Abnormalities and Venous Beading Have Different Genetic Profiles in Caucasian Patients with Non-Proliferative Diabetic Retinopathy

Diabetic Retinopathy (DR) is a leading cause of preventable visual impairment in the working age population. Despite the increasing prevalence of DR, there remain gaps in our understanding of its pathophysiology. This is a prospective case-control study comparing the genetic profiles of patients with no DR vs. non-proliferative DR (NPDR) focusing on intraretinal microvascular abnormalities (IRMA) and venous beading (VB) in Caucasians. A total of 596 participants were recruited to the study; 199 with moderate/severe NPDR and 397 with diabetes for at least 5 years without DR. Sixty-four patients were excluded due to technical issues. In total, 532 were analysed; 181 and 351 were in the NPDR group and no DR group, respectively. Those with severe IRMA and VB had distinctly different genetic profiles from each other and from the no DR group, which further supports the theory that these two features of DR might have different etiologies. This also suggests that IRMA and VB are independent risk factors for the development of PDR and may have different pathophysiologies. If these findings are confirmed in larger studies, this could pave the way for personalised treatment options for those more at risk of developing different features of NPDR.

Association between the VEGFR-2 -604T/C polymorphism (rs2071559) and type 2 diabetic retinopathy

This retrospective case-control study examined the association between the rs2071559 (-604T/C) single nucleotide polymorphism (SNP) in the vascular endothelial growth factor receptor (VEGFR)-2 gene and the risk of diabetic retinopathy (DR) in Northern Han Chinese. This study included patients diagnosed with diabetes mellitus (DM) in Shijiazhuang between 07/2014 and 07/2016. The healthy controls were unrelated individuals who received routine physical examinations. The diabetic patients were grouped as DM (diabetes but no fundus examination abnormalities), proliferative DR (PDR), and non-proliferative DR (NPDR). Finally, 438 patients were included: 114 controls and 123, 105, and 96 patients in the DM, NPDR, and PDR groups, respectively. In the multivariable analyses and all genetic models, the VEGFR-2 rs2071559 SNP was not associated with DR (among all diabetic patients) or with PDR (among the patients with DR) after adjustment for age, sex, duration of DM, blood glucose, systolic blood pressure, diastolic blood pressure, and body mass index (all P > 0.05). In conclusion, the VEGFR-2- 604T/C rs2071559 SNP is not associated with DR or PDR in the Han Chinese population of Shijiazhuang (China).

VEGF and eNOS genes polymorphism features in patients with diabetes mellitus with and without initial non-proliferative diabetic retinopathy

The endothelial NO synthase (eNOS) and vascular endothelial growth factor (VEGF) imbalance and the polymorphism of these genes may be the predisposition for diabetic retinopathy (DR) development and progression.The aim: to analyze VEGF (rs699947 and rs3025039) and eNOS (rs2070744) genes polymorphism and their combinations in patients with type 2 diabetes mellitus (DM2) with and without initial non-proliferative DR.Materials and methods. The study included 200 patients with type 2 diabetes (155 women and 45 men, age – 43–70 years): 111 people without and 89 people with DR. The polymorphism of the regulatory regions of VEGF (rs699947 and rs3025039) and eNOS (rs2070744) genes was studied using restriction fragment length polymorphism analysis and TaqMan Real-Time PCR by. Statistical processing was carried out using the software packages Statistica 10.0, SPSS Statistics 23 and the package of original programs for volumetric processing of bioinformation.Results. The VEGF-2578 heterozygosity and two complex genotypes – VEGF-2578CA:VEGF+936CC and NOS3-786CT:VEGF-2578CA:VEGF+936CC – signifi cantly decreased in patients with DR. The predisposition to early DR development to minor genotype of eNOS gene in the NOS3-786CC:VEGF+936CT complex and signifi cantly decreased the homozygous wild-type eNOS genotype in DM2 patients with ophthalmopathology were shown. NOS3-86TT:VEGF2578AA genotype signifi cantly decreased in group with retinopathy developing and the glycated hemoglobin high level.Conclusion. Along with the clinical risk factors for the development of DR in DM2, the genetic polymorphism of the regulatory regions of the genes analyzed by us has a signifi cant weight. When analyzing potential genetic markers, it is important to consider possible joint epistatic/hypostatic effects. The complex analysis of polymorphic gene can help early prognosis of the DR development.

Association of four gene polymorphisms in Chinese Guangxi population with diabetic retinopathy in type 2 diabetic patients

Background

Diabetic retinopathy (DR) is one of the most common chronic microvascular complications of diabetes. Many studies have suggested that genetic factors are important in the context of DR. This study evaluated the associations of GWAS (Genome-wide association study) -identified DR-associated SNPs in a Chinese population in Guangxi Province with type 2 diabetes mellitus (T2DM).

Methods

A total of 386 hospitalized T2DM patients without proliferative diabetic retinopathy (PDR) and 316 hospitalized T2DM patients with PDR were included in this case–control study. Four tag SNPs, including rs1800896 in the IL-10 gene, rs2010963 in the VEGFA gene, rs2070600 in the RAGE gene and rs2910164 in the miR-146a gene, were examined using KASP (kompetitive allele specific PCR) genotyping assays.

Results

There were no significant differences in the genotype or allele frequencies of the miR-146a polymorphism (rs2910164) between subjects with PDR and those without DR. The TC genotype of rs1800896 was determined to be associated with an increased risk of PDR (the odds ratio (OR) was 2.366, with a 95% confidence interval (CI) ranging from 1.144 to 4.894). The CG genotypes of rs2010963 was associated with an decreased risk of PDR (the OR was 0.588, with a 95% CI ranging from 0.366 to 0.946). Regarding rs2070600, 2 genotypes (TT and CT) were associated with a decreased risk of PDR (the OR of the TT genotype was 0.180, with a 95% CI ranging from 0.037 to 0.872, and the OR of the CT genotype was 0.448, with a 95% CI ranging from 0.266 to 0.753).

Conclusions

The rs1800896 polymorphisms in the IL-10 gene, rs2010963 in the VEGFA gene and rs2070600 in the RAGE gene are associated with the risk of PDR in the Han Chinese population of Guangxi Province. Our findings provide suggestive evidence that these polymorphisms may be involved in the pathogenesis of PDR and should be investigated further.

Association of Genetic Variants in ANGPT/TEK and VEGF/VEGFR with Progression and Survival in Head and Neck Squamous Cell Carcinoma Treated with Radiotherapy or Radiochemotherapy

Angiogenesis is essential for growth, progression, and metastasis of solid tumors. Vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR) and angiopoietin (ANGPT)/ tyrosine kinase endothelial (TEK) signaling plays an important role in regulating angiogenesis. Very little is known about the effects of single-nucleotide polymorphisms (SNPs) in angiogenesis-related genes on treatment outcome in head and neck squamous cell carcinoma (HNSCC). Therefore, we evaluated the association between SNPs in ANGPT1, ANGPT2, TEK, VEGF, VEGFR1, and VEGFR2 genes and five clinical endpoints in 422 HNSCC patients receiving radiotherapy alone or combined with chemotherapy. Multivariate analysis showed an association of ANGPT2 rs3739391, rs3020221 and TEK rs639225 with overall survival, and VEGF rs2010963 with overall and metastasis-free survival. VEGFR2 rs1870377 and VEGF rs699947 affected local recurrence-free survival in all patients. In the combination treatment subgroup, rs699947 predicted local, nodal, and loco-regional recurrence-free survival, whereas VEGFR2 rs2071559 showed an association with nodal recurrence-free survival. However, these associations were not statistically significant after multiple testing correction. Moreover, a strong cumulative effect of SNPs was observed that survived this adjustment. These SNPs and their combinations were independent risk factors for specific endpoints. Our data suggest that certain germline variants in ANGPT2/TEK and VEGF/VEGFR2 axes may have predictive and prognostic potential in HNSCC treated with radiation or chemoradiation.

Influence of polymorphisms in VEGF, TNF-α, and GSTP1 genes on retinopathy of prematurity risk: a Meta-analysis

Purpose: To investigate the influence of polymorphisms in vascular endothelial growth factor (VEGF), tumor necrosis factor-α (TNF-α), and glutathione S-transferase Pi isoform (GSTP1) genes on retinopathy of prematurity (ROP) risk, we performed a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-compliant meta-analysis.Methods: An exhaustive search was conducted in PubMed, Web of Science, and CNKI for genetic studies evaluating the relationship between VEGF (-460 T/C, +936 C/T, -634 G/C, and -2578 C/A), TNF-α (-308 G/A) and GSTP1 (Ile/Val) polymorphisms and ROP risk from inception until November 2019. Odds ratio (OR) with the 95% confidence interval (CI) were used for estimating combined effect size. The quality of the included studies was evaluated using the Newcastle-Ottawa Scale (NOS).Results: A total of 14 studies met the inclusion criteria. The meta-analyses revealed that VEGF - 460 T/C was associated with ROP risk in the allele model (C vs. T, OR = 0.83, 95% CI: 0.74-0.94, P_OR=0.004), homozygous gene model (CC vs. TT, OR = 0.70, 95% CI: 0.54-0.91, P_OR=0.008), dominant gene model (CC + TC vs. TT, OR = 0.80, 95% CI: 0.67-0.95, P_OR = 0.012), and recessive gene model (CC vs. TC + TT, OR = 0.74, 95% CI: 0.59-0.94, P_OR = 0.014). However, we did not find significant differences in the genotype and allele distribution of VEGF + 936 C/T, -634 G/C, -2578 C/A, TNF-α - 308 G/A and GSTP1 Ile/Val polymorphisms, between ROP and control group (p > .05).Conclusions: VEGF polymorphism -460 T/C was associated with a lower ROP risk. Further research is warranted to investigate haplotype effects of VEGF polymorphisms on the risk of ROP.

Genetics of Diabetic Retinopathy

PURPOSE OF REVIEW

The goal of this paper is to review the latest findings in understanding the genetics of diabetic retinopathy. We highlight recent literature using a variety of molecular genetic techniques to identify variants which contribute to genetic susceptibility for diabetic retinopathy.

RECENT FINDINGS

New genome-wide association study (GWAS) and whole-exome sequencing approaches have been utilized to identify both common and rare variants associated with diabetic retinopathy. While variants have been identified in isolated studies, no variants have been replicated across multiple studies. The identification of genetic factors associated with diabetic retinopathy remains elusive. This is due to the multifactorial nature of the disease, small sample sizes for GWAS, and difficulty in controlling covariates of the disease. Larger populations as well as utilization of new sequencing and data analysis techniques may lead to new insights into genetic factors associated with diabetic retinopathy in the future.

Diabetic macular oedema: under-represented in the genetic analysis of diabetic retinopathy

Diabetic retinopathy, a complication of both type 1 and type 2 diabetes, is a complex disease and is one of the leading causes of blindness in adults worldwide. It can be divided into distinct subclasses, one of which is diabetic macular oedema. Diabetic macular oedema can occur at any time in diabetic retinopathy and is the most common cause of vision loss in patients with type 2 diabetes. The purpose of this review is to summarize the large number of genetic association studies that have been performed in cohorts of patients with type 2 diabetes and published in English-language journals up to February 2017. Many of these studies have produced positive associations with gene polymorphisms and diabetic retinopathy. However, this review highlights that within this large body of work, studies specifically addressing a genetic association with diabetic macular oedema, although present, are vastly under-represented. We also highlight that many of the studies have small patient numbers and that meta-analyses often inappropriately combine patient data sets. We conclude that there will continue to be conflicting results and no meaningful findings will be achieved if the historical approach of combining all diabetic retinopathy disease states within patient cohorts continues in future studies. This review also identifies several genes that would be interesting to analyse in large, well-defined cohorts of patients with diabetic macular oedema in future candidate gene association studies.

Association of VEGFA variants with altered VEGF secretion and type 2 diabetes: A case-control study

BACKGROUND

Vascular endothelial growth factor (VEGF) contributes to type 2 diabetes (T2DM) pathogenesis, and genetic variations in VEGFA gene were suggested to influence VEGF secretion and T2DM pathogenesis.

AIM

To evaluate the association of specific VEGFA variants with altered VEGF levels, and with T2DM among Tunisians.

SUBJECTS AND METHODS

A retrospective case-control study, performed on 815 T2DM patients, and 805 healthy controls. VEGF levels were measured by ELISA, genotyping of VEGFA variants was done by allelic exclusion method (real-time PCR).

RESULTS

MAF of rs1570360, rs2010963, rs25648, rs833068, rs3025036, and rs3025039 were significantly different between T2DM cases and controls. Increased T2DM risk was associated with rs699947, rs1570360, and rs3025020, while reduced T2DM risk was seen with rs1547651, rs2010963, rs25648, rs3025036, and rs3025039 genotypes, thus assigning T2DM susceptibility and protection, respectively. Reduced VEGF levels were associated with rs833061, rs2010963, and rs3025039 heterozygosity and rs3025036 major allele homozygosity in T2DM cases, while increased VEGF levels were seen in rs833070 homozygous major allele genotype. Both rs699947 and rs1570360 positively, while rs2010963 and rs3025036 negatively correlated with fasting glucose. In addition, rs699947 positively correlated with LDL-cholesterol, and rs3025039 positively correlated with diabetes duration, but negatively with HbA1c and serum triglycerides. Haploview analysis identified Block 1 containing 8 loci, and Block 2 with the remaining 3 loci. Haplotypes ACTGCCGG and AACGGCGA (Block 1) were negatively associated with T2DM, while haplotype CCC was positively and haplotype CGC (Block 2) were negatively associated with T2DM.

CONCLUSION

This study confirms the contribution of altered VEGF secretion, resulting from genetic variation in VEGFA gene into T2DM pathogenesis, hence supporting role for VEGFA as T2DM candidate locus.

IGF1 gene polymorphisms associated with diabetic retinopathy risk in Chinese Han population

Objective

This study aimed to explore the association of insulin-like growth factor 1 gene (IGF1) polymorphisms with diabetic retinopathy (DR) in a Chinese Han population.

Methods

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used for genotyping. Genotype frequencies were compared by chi-square test. Odds ratio (OR) with 95% confidence interval (95%CI) was calculated to express the risk intensity of DR. Linkage disequilibrium between IGF1 polymorphisms was analyzed by Haploview. Serum IGF1 concentration was measured by enzyme-linked immunosorbent assays (ELISA) and assessed by student's t test.

Results

AG genotype of rs6218 and TT genotype of rs35767 were significantly associated with the elevated risk of DR (rs6218: OR=1.77, P=0.04; rs35767: OR=2.32, P=0.03) and type II diabetes mellitus (T2DM) (rs6218: OR=1.92, P=0.00. rs35767: OR=2.29, P=0.02). Only T allele of rs35767 significantly increased the risk of DR (OR=1.45, P=0.04), however, rs6218 (OR=1.92, P=0.00), rs35767 (OR=0.02, P=0.02) and rs5742612 (OR=2.21, P=0.04) showed obvious association with T2DM. Haplotypes were only associated with T2DM, but not DR. Minor allele homozygote of rs35767 was obviously correlated with serum IGF1 level.

Conclusion

IGF1 rs6218 and rs35767 polymorphisms contribute to the risk of DR. IGF1 rs35767 polymorphism may participate in the regulation of serum IGF1 concentration in DR.