Vascular endothelial growth factor polymorphisms are involved in the late vascular complications in Type II diabetic patients

VEGF Polymorphisms (VEGF-936 C/T, VEGF-634 G/C and VEGF-2578 C/A) and Cardiovascular Implications in Long COVID Patients

The COVID-19 pandemic has raised awareness of the virus's long-term non-pulmonary consequences. This study examined the relationship between genetic polymorphisms of VEGF and cardiac dysfunction and subclinical atherosclerosis in patients recovering from COVID-19. This study included 67 patients previously diagnosed with COVID-19. VEGF-936C/T, VEGF-634G/C, and VEGF-2578C/A statuses were determined. Conventional echocardiography and arterial parameters assessments were performed at inclusion and at six months after the first assessment. For VEGF-936C/T, dominant and over-dominant models showed a significant increase in ejection fraction at six months after COVID (p = 0.044 and 0.048) and was also a predictive independent factor for the augmentation index (β = 3.07; p = 0.024). The dominant model showed a rise in RV-RA gradient (3.702 mmHg) (p = 0.028 95% CI: 0.040-7.363), with the over-dominant model indicating a greater difference (4.254 mmHg) (p = 0.025 95% CI: 0.624-7.884). The findings for VEGF-634G/C were not statistically significant, except for a difference in TAPSE during initial evaluation, using the codominant model. For VEGF-2578C/A, a difference in ventricular filling pressure (E/E'ratio) was best described under the recessive model. Our research suggests that the VEG-936C/T genotype may impact the baseline level and subsequent changes in cardiac function and subclinical atherosclerosis. These findings offer valuable insights into the complex correlation between genetic polymorphisms and cardiovascular disfunction in long COVID patients.

Association of Vascular Endothelial Growth Factor (VEGF) and Mouse Model Minute 2 (MDM2) Polymorphisms With Diabetic Retinopathy in a Northwest Indian Population: A Case-Control Study

INTRODUCTION

Diabetic retinopathy (DR), a microvascular complication of type 2 diabetes (T2D), results from complex interactions of genetic and environmental factors. Vascular endothelial growth factor (VEGF) and mouse model minute 2 (MDM2)are upregulated in the retina due to diabetes, which increases the risk of DR. VEGFA and MDM2 genetic variations can influence DR risk. The present case-control study was conducted to evaluate the association of VEGFA and MDM2 promoter variants with DR in a population from Punjab, Northwest India.

METHODS

A total of 414 DR patients, 425 T2D patients without DR, and 402 healthy controls were screened for VEGFA -2578C/A (rs699947), VEGFA -2549I/D (rs35569394), VEGFA -7C/T (rs25648), and MDM2 rs3730485 polymorphisms using polymerase chain reaction (PCR)-based methods.

RESULTS

VEGFA -2549 I allele (OR = 1.35 (1.00-1.81), p = 0.043) and II genotype (OR = 1.78 (1.00-3.15), p = 0.047) were significantly associated with increased risk of DR. VEGFA -7 CT genotype conferred reduced risk of DR (OR = 0.28 (0.20-0.38); p = <0.001). VEGFA -2578 and MDM2 rs3730485 showed no significant association with DR. A-I-T (OR = 0.30 (0.20-0.44); p = <0.001) and C-D-T (OR = 0.33 (0.16-0.65); p = 0.002) haplotypes of rs699947-rs35569394-rs25648 polymorphisms showed decreased risk of DR.

CONCLUSIONS

I allele and II genotype of VEGFA -2549, CT genotype of VEGFA -7, and C-I-C and A-D-C haplotypes of rs699947-rs35569394-rs25648 polymorphisms were significantly associated with DR risk in a Northwest Indian population. This is the first study worldwide to report DR risk with VEGFA promoter variants together.

Metabolic memory in diabetic foot syndrome (DFS): MICRO-RNAS, single nucleotide polymorphisms (SNPs) frequency and their relationship with indices of endothelial function and adipo-inflammatory dysfunction

BACKGROUND

Diabetic foot is a significant cause of morbidity in diabetic patients, with a rate that is approximately twice that of patients without foot ulcers. "Metabolic memory" represents the epigenetic changes induced by chronic hyperglycaemia, despite the correction of the glucose levels themselves. These epigenetic modifications appear to perpetuate the damage caused by persistently elevated glucose levels even in their absence, acting at various levels, mostly affecting the molecular processes of diabetic ulcer healing.

METHODS

The aim of our cross-sectional study was to analyse a cohort of patients with diabetes with and without lower limb ulcers. We examined the effects of epigenetic changes on miRNA 126, 305, and 217 expression and the frequency of the SNPs of genes encoding inflammatory molecules (e.g., IL-6 and TNF-alpha) and their correlations with serum levels of proangiogenic molecules (e.g., ENOS, VEGF and HIF-1alpha) and several adipokines as well as with endothelial dysfunction, assessed noninvasively by reactive hyperaemia peripheral artery tonometry. Between March 2021 and June 2022, 110 patients were enrolled into the study: 50 diabetic patients with diabetic foot injuries, 40 diabetic patients without ulcerative complications and 20 nondiabetic patients as the control group.

RESULTS

Diabetic subjects with lower limb ulcerative lesions exhibited higher levels of inflammatory cytokines, such as VEGF (191.40 ± 200 pg/mL vs. 98.27 ± 56.92 pg/mL vs. 71.01 ± 52.96 pg/mL; p = 0.22), HIF-1alpha (40.18 ± 10.80 ng/mL vs. 33.50 ± 6.16 ng/mL vs. 33.85 ± 6.84 ng/mL; p = 0.10), and Gremlin-1 (1.72 ± 0.512 ng/mL vs. 1.31 ± 0.21 ng/mL vs. 1.11 ± 0.19 ng/mL; p < 0.0005), than those without lower limb ulcers and healthy controls. Furthermore, we observed that miR-217-5p and miR-503-5p were 2.19-fold (p < 0.05) and 6.21-fold (p = 0.001) more highly expressed in diabetic foot patients than in healthy controls, respectively. Additionally, diabetic patients without lower limb ulcerative complications showed 2.41-fold (p = 0) and 2.24-fold (p = 0.029) higher expression of miR-217-5p and miR-503-5p, respectively, than healthy controls. Finally, diabetic patients with and without ulcerative complications of the lower limbs showed higher expression of the VEGFC2578A CC polymorphism (p = 0.001) and lower expression of the VEGFC2578A AC polymorphism (p < 0.005) than the healthy control population. We observed a significant increase in Gremlin-1 levels in patients with diabetic foot, suggesting that this inflammatory adipokine may serve as a predictive marker for the diagnosis of diabetic foot.

CONCLUSIONS

Our results highlighted that patients with diabetic foot showed predominant expression of the VEGF C2578A CC polymorphism and reduced expression of the AC allele. Additionally, we found an overexpression of miR-217-5p and miR-503-5p in diabetic patients with and without diabetic foot syndrome compared with healthy controls. These results align with those reported in the literature, in which the overexpression of miR-217-5p and miR-503-5p in the context of diabetic foot is reported. The identification of these epigenetic modifications could therefore be helpful in the early diagnosis of diabetic foot and the treatment of risk factors. However, further studies are necessary to confirm this hypothesis.

VEGF and eNOS variants may influence intervertebral disc degeneration

BACKGROUND

Intervertebral disc degeneration (IDD) is a common and complex condition. Vascular endothelial growth factor (VEGF) is one of the key regulators of angiogenesis and vascular permeability. Nitric oxide (NO) plays a role in various physiological events. The endothelial nitric oxide synthase (eNOS) that catalyses NO generation are crucial for the regulation of NO level. This study aimed to evaluate the association between VEGF/ eNOS gene variants with IDD.

MATERIALS AND METHODS

Two hundred ninety-one subjects (111 IDD patients and 180 controls) were included in the present case-control study. VEGF -2549 insertion/deletion (I/D) and eNOS VNTR variants were analysed by PCR method. The results of this analysis were evaluated for statistical significance.

RESULTS

There were no statistically significant differences in genotype and allele distribution of VEGF -2549 I/D/ eNOS VNTR variants between IDD patients and control subjects. We then evaluated the association between the allele frequencies of these variants and clinical features of IDD. Lumber IDD was more common in patients carrying VEGF I/D variant D allele (p < 0.001). Also, patients with lumbar disc herniation, cervical disc herniation, lumbar stenosis, and lumbar IDD had more 4 b allele (p = 0.005, p < 0.001, p < 0.001, and p = 0.03, respectively).

CONCLUSIONS

In conclusion, this study demonstrates first time that some clinical characteristics of IDD have been associated with allele frequencies of VEGF -2549 I/D/ eNOS VNTR variants.

Clinical Implications of MiR128, Angiotensin I Converting Enzyme and Vascular Endothelial Growth Factor Gene Abnormalities and Their Association with T2D

Type 2 DM (T2D) results from the interaction of the genetic and environmental risk factors. Vascular endothelial growth factor (VEGF), angiotensin I-converting enzyme (ACE), and MicroRNAs (MiRNAs) are involved in important physiological processes. Gene variations in VEGF, ACE and MiRNA genes are associated with diseases. In this study we investigated the associations of the VEGF-2578 C/A (rs699947), VEGF-2549 insertion/deletion (I/D), and ACE I/D rs4646994 and Mir128a (rs11888095) gene variations with T2D using the amplification refractory mutation system PCR (ARMS-PCR) and mutation specific PCR (MSP). We screened 122 T2D cases and 126 healthy controls (HCs) for the rs699947, and 133 T2D cases and 133 HCs for the VEGF I/D polymorphism. For the ACE I/D we screened 152 cases and 150 HCs, and we screened 129 cases and 112 HCs for the Mir128a (rs11888095). The results showed that the CA genotype of the VEGF rs699947 and D allele of the VEGF I/D polymorphisms were associated with T2D with OR =2.01, p-value = 0.011, and OR = 2.42, p-value = 0.010, respectively. The result indicated the D allele of the ACE ID was protective against T2D with OR = 0.10, p-value = 0.0001, whereas the TC genotype and the T allele of the Mir128a (rs11888095) were associated with increased risk to T2D with OR = 3.16, p-value = 0.0001, and OR = 1.68, p-value = 0.01, respectively. We conclude that the VEGF (rs699947), VEGF I/D and Mir128a (rs11888095) are potential risk loci for T2D, and that the D allele of the ACE ID polymorphism may be protective against T2D. These results help in identification and stratification for the individuals that at risk for T2D. However, future well-designed studies in different populations and with larger sample sizes are required. Moreover, studies to examine the effects of these polymorphisms on VEGF and ACE proteins are recommended.

Genetics of Diabetic Retinopathy, a Leading Cause of Irreversible Blindness in the Industrialized World

Diabetic retinopathy (DR) is a chronic complication of diabetes and a leading cause of blindness in the industrialized world. Traditional risk factors, such as glycemic control and duration of diabetes, are unable to explain why some individuals remain protected while others progress to a more severe form of the disease. Differences are also observed in DR heritability as well as the response to anti-vascular endothelial growth factor (VEGF) treatment. This review discusses various aspects of genetics in DR to shed light on DR pathogenesis and treatment. First, we discuss the global burden of DR followed by a discussion on disease pathogenesis as well as the role genetics plays in the prevalence and progression of DR. Subsequently, we provide a review of studies related to DR’s genetic contribution, such as candidate gene studies, linkage studies, and genome-wide association studies (GWAS) as well as other clinical and meta-analysis studies that have identified putative candidate genes. With the advent of newer cutting-edge technologies, identifying the genetic components in DR has played an important role in understanding DR incidence, progression, and response to treatment, thereby developing newer therapeutic targets and therapies.

Growth Factor Deregulation and Emerging Role of Phosphatases in Diabetic Peripheral Artery Disease

Peripheral artery disease is caused by atherosclerosis of lower extremity arteries leading to the loss of blood perfusion and subsequent critical ischemia. The presence of diabetes mellitus is an important risk factor that greatly increases the incidence, the progression and the severity of the disease. In addition to accelerated disease progression, diabetic patients are also more susceptible to develop serious impairment of their walking abilities through an increased risk of lower limb amputation. Hyperglycemia is known to alter the physiological development of collateral arteries in response to ischemia. Deregulation in the production of several critical pro-angiogenic factors has been reported in diabetes along with vascular cell unresponsiveness in initiating angiogenic processes. Among the multiple molecular mechanisms involved in the angiogenic response, protein tyrosine phosphatases are potent regulators by dephosphorylating pro-angiogenic tyrosine kinase receptors. However, evidence has indicated that diabetes-induced deregulation of phosphatases contributes to the progression of several micro and macrovascular complications. This review provides an overview of growth factor alterations in the context of diabetes and peripheral artery disease, as well as a description of the role of phosphatases in the regulation of angiogenic pathways followed by an analysis of the effects of hyperglycemia on the modulation of protein tyrosine phosphatase expression and activity. Knowledge of the role of phosphatases in diabetic peripheral artery disease will help the development of future therapeutics to locally regulate phosphatases and improve angiogenesis.

Associations between Vascular Endothelial Growth Factor Gene Polymorphisms and Different Types of Diabetic Retinopathy Susceptibility: A Systematic Review and Meta-Analysis

BACKGROUND

Vascular endothelial growth factor (VEGF) gene polymorphisms have been shown to be associated with the risk of diabetic retinopathy (DR), but the results were inconsistent. The aim of this study was to systematically assess the associations between VEGF gene polymorphisms and different types of DR (nonproliferative DR and proliferative DR).

METHODS

Electronic databases PubMed, Embase, Web of Science, CNKI, and WANFANG DATA were searched for articles on the associations between VEGF gene polymorphisms and different types of DR up to November 6, 2019. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated, and subgroup analyses were conducted by ethnicity. Sensitivity analysis was conducted to assess the stability of the results. Publication bias was assessed by using the Egger regression asymmetry test and visualization of funnel plots. A systematic review was conducted for polymorphisms with a high degree of heterogeneity (I ² > 75%) or studied in only one study.

RESULTS

A total of 13 and 18 studies analyzed the associations between VEGF SNPs and nonproliferative DR (NPDR) as well as proliferative DR (PDR), respectively. There were significant associations between rs2010963 and NPDR in Asian (dominant model: OR = 1.29, 95%CI = 1.04 - 1.60); and rs2010963 is associated with PDR in total population (dominant model: OR = 1.20, 95%CI = 1.03 - 1.41), either Asian (recessive model: OR = 1.57, 95%CI = 1.04 - 2.35) or Caucasian (recessive model: OR = 1.83, 95%CI = 1.28 - 2.63). Rs833061 is associated with PDR in Asian (recessive model: OR = 1.58, 95%CI = 1.11 - 2.26). Rs699947 is associated with NPDR in the total population (dominant model: OR = 2.04, 95%CI = 1.30 - 3.21) and associated with PDR in Asian (dominant model: OR = 1.72, 95%CI = 1.05 - 2.84).

CONCLUSIONS

Rs2010963, rs833061, and rs699947 are associated with NPDR or PDR, which may be involved in the occurrence and development of DR.

Identifying Genetic Risk Factors for Diabetic Macular Edema and the Response to Treatment

Diabetic retinopathy (DR) is the most common microvascular complication of diabetes mellitus (DM). DR is complex and the term encompasses several clinical subtypes of diabetic eye disease, including diabetic macular edema (DME), the most frequent cause of central vision loss in DR patients. Both genetic and environmental factors contribute to the pathophysiology of DR and its subtypes. While numerous studies have identified several susceptibility genes for DR, few have investigated the impact of genetics on DME susceptibility. This review will focus on the current literature surrounding genetic risk factors associated with DME. We will also highlight the small number of studies investigating the genetics of response to antivascular endothelial growth factor (anti-VEGF) injection, which is used to treat DME.

VEGF Promoter Region 18-bp Insertion-Deletion Polymorphism in Sickle Cell Disease Patients with Microalbuminuria: A Pilot Study

Purpose

Vascular endothelial growth factor (VEGF) is a potent inducer of micro vascular permeability thus leading to nephropathy. Insertion/deletion (I/D) polymorphism of 18 bp at - 2549 position in VEGF gene causes increased transcription leading to increased production of VEGF. Thus, we aimed to associate I/D polymorphism of the 18 bp fragment at - 2549 position of the promoter region of VEGF gene with sickle cell nephropathy (SCN).

Methods

This observational analytical case control study included 30 subjects each of SCN, sickle cell disease (SCD) without nephropathy and the control group. The subjects were assessed for various hematological and biochemical parameters. Further, 18 bp I/D polymorphism of VEGF gene in all three study groups was assessed by polymerase chain reaction followed by electrophoresis and compared.

Result

Though increased frequency of both DD genotype and D allele was found in SCN compared to SCD and control, only frequency of D allele was found to be significantly higher (p = 0.04). D allele posed marginal risk of microalbuminuria in SCD subjects compared to controls (OR = 2.11) as well as to SCD without MA subjects (OR = 1.84).

Conclusion

D allele in I/D polymorphism in the promoter region of VEGF gene may be associated with marginal increase in risk of susceptibility to sickle cell nephropathy.

Association of 18bp insertion/deletion polymorphism, at -2549 position of VEGF gene, with diabetic vascular complications in type 2 diabetes mellitus

PURPOSE

Diabetes mellitus type 2 (T2DM) and its vascular complications are a serious world health problem. For this reason it is important to look for new diabetes complication risk factors. The aim of this study was to determine whether 18-bp insertion/deletion (I/D) polymorphism at -2549 position of the vascular endothelial growth factor (VEGF) gene is associated with diabetic vascular complications (DVC).

MATERIAL AND METHODS

Caucasian subjects (n = 100) with T2DM were recruited for this study. Genotyping of the VEGF gene I/D polymorphism was done by the polymerase chain reaction (PCR) method. The results were correlated with laboratory and clinical data.

RESULTS

In our population heterozygous of the VEGF gene polymorphism was observed most frequently (57%). DVC were observed in 53 patients. Heterozygous T2DM patients significantly more often suffered from heart failure (HF) and stroke (p = 0.05). Amongst all the DVC, D allele of the VEGF polymorphism had a significantly increased risk of diabetic retinopathy (DR) (OR = 1.31; p = 0.033) irrespective of the duration of diabetes, BMI, the glycemia control expressed by HbA1c, renal function, lipid values or applied treatment. The studied polymorphism did not correlate with coronary heart disease, peripheral vascular disease, cardiovascular death, diabetic kidney disease or applied treatment.

CONCLUSIONS

The multivariate logistic regression analysis showed that the D allele in the promoter region of the VEGF gene is an independent risk factor of DR irrespective of other laboratory and clinical variables in T2DM patients. Our study suggests that I/D allele in the studied gene is associated with HF and strokes.

The Association Analysis of Vascular Endothelial Growth Factor -2549 Insertion/ Deletion Variant and Endometriosis Risk

Endometriosis is a debilitating disorder, defined as the presence of endometrial gland and stroma outside of the uterus. It may affect angiogenesis and vascular endothelial growth factor (VEGF) is one of the angiogenic factors that plays an important role in both physiological and pathological angiogenesis. The present study aimed to evaluate the association of VEGF -2549 insertion/deletion (I/D) polymorphism with endometriosis. This case-control study enrolled 244 (100 cases and 144 controls) women who were admitted for laparoscopy or laparotomy for gynecological procedures. Genomic DNA was separated from peripheral blood leukocytes and polymerase chain reaction (PCR) amplification was performed for genotyping of the VEGF gene Insertion/Deletion (I/D) polymorphism. The frequency of the II, ID, and DD genotype was 14%, 52% and 34% in patients versus 18.8%, 47.8% and 34% in controls. The results did not provide any evidence supporting the endometriosis risk related to the VEGF polymorphism in a group of Iranian women population.

Association of vascular endothelial growth factor expression and polymorphisms with the risk of gestational diabetes mellitus

OBJECTIVE

To study the associations of vascular endothelial growth factor (VEGF) expression and its gene polymorphisms with the risk of gestational diabetes mellitus (GDM).

METHODS

A total of 239 GDM patients (GDM group) and 275 healthy pregnant women (Control group) were included in this study. VEGF genotypes (including rs2146323, rs2010963, rs3025039, rs3025010, and rs833069) were analyzed by TaqMan assay. ELISA was used to determine the serum VEGF levels. The software SHEsis was performed to analyze haplotypes.

RESULTS

The carrier with the rs2146323 AA, CA+AA genotypes, and A allele, as well as the rs3025039 CT, TT, CT+TT genotypes, and T allele showed the increased risk of GDM (all P < 0.05), but the distributions of genotype and allele at rs2010963, rs3025010, and rs833069 were not significantly different between GDM patients and controls (all P > 0.05). Notably, the frequency of rs2010963-rs833069-rs2146323-rs3025010 haplotypes CAAC, CAAT, CACC, CACT, GACT, and GGCT was found statistically different between GDM patients and controls (all P < 0.05). The patients with rs3025039 CT+TT genotype had higher VEGF levels than those with CC genotype (all P < 0.05). Besides, age, family histories of diabetes, previous GDM, hypertension, pre-pregnancy body mass index, fasting plasma glucose, fasting insulin, homeostasis model assessment (HOMA)-IR, rs2146323 CA+AA, rs3025039 CT+TT, and VEGF expression level were independent risk factors, while HOMA-β was an independent protective factor for GDM (all P < 0.05).

CONCLUSION

VEGF rs2146323 and rs3025039 polymorphisms and its expression were significantly correlated with the risk of GDM, providing a great clinical value for GDM assessment and diagnosis.

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.

Genetic determinants of essential hypertension in the population of Tatars from Russia

OBJECTIVE

Systemic inflammation and impaired function of endothelium play an important role in the development of hypertension. Our study aimed to analyze an association between essential hypertension and polymorphic markers in candidate genes in the group of 530 Tatars from the Republic of Bashkortostan, Russia.

METHODS

The study group consisted of 216 male patients with essential hypertension (mean age 48.92 ± 8.8 years) and 314 healthy individuals of corresponding sex and age without history of cardiovascular disease. Association between studied polymorphisms and essential hypertension was analyzed using PLINK.

RESULTS

We detected an association between EDNRB rs5351, VEGFA -2549(18)I/D, and ADRB2 rs1042713 polymorphisms and essential hypertension in men of Tatar ethnic origin. EDNRB, VEGFA, and VCAM1 single-nucleotide polymorphisms were associated with SBP and DBP. However, only EDNRB rs5351 remained associated with hypertension after Bonferroni correction for multiple testing. A Markov chain Monte Carlo-based approach implemented in the APSampler program was used to analyze association of genotype and/or allele combinations with disease. The most influential in conferring risk of hypertension was EDNRBG/G+ADRB2A+VCAM1A combination (odds ratio = 4.15, PBonf = 5.43 × 10).

CONCLUSION

Our results suggest that rs5351 single-nucleotide polymorphism is a strong independent predictor of essential hypertension in men of Tatar ethnic origin.

Association between the vascular endothelial growth factor single nucleotide polymorphisms and diabetic retinopathy risk: A meta-analysis

BACKGROUND

The aim of the present study was to reveal the relationship between vascular endothelial growth factor (VEGF) single nucleotide polymorphisms (SNPs) and susceptibility to diabetic retinopathy (DR).

METHODS

A literature review was conducted (PubMed, Web of Science, Embase) to identify papers about VEGF SNPs and DR published up to 23 September 2015. The VEGF gene SNPs analyzed with regard to DR susceptibility were rs2010963 (G > C), rs833061 (T > C), rs699947 (C > A), rs3025039 (C > T) and rs1570360 (G > A). Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated, and meta-analyses were performed using fixed or random effects models.

RESULTS

Sixteen studies were included in the meta-analysis. Significant associations between the rs3025039 (C > T) polymorphism and increased DR risk were found in the allele model (T/C; pooled OR 1.60, 95% CI 1.07-2.41, P = 0.02), homozygote model (TT/CC; pooled OR 2.08, 95% CI 1.29-3.35, P = 0.003), heterozygote model (TC/CC; pooled OR 1.68, 95% CI 1.04-2.72, P = 0.04), dominant model (TT+TC/CC; pooled OR 1.72, 95% CI 1.06-2.80, P = 0.03), and recessive model (TT/TC+CC; pooled OR 1.80, 95% CI 1.12-2.90, P = 0.02). For rs833061, a significant association between VEGF SNPs and DR was found only in the allele model (C/T; pooled OR 6.34, 95% CI 2.10-19.14, P = 0.001).

CONCLUSIONS

The rs3025039 and rs833061 SNPs are most likely associated with an increased risk of DR. The T allele in rs3025039 and the C allele in rs833061 are associated with increased DR susceptibility.

Ethnic differences in the +405 and -460 vascular endothelial growth factor polymorphisms and peripheral neuropathy in patients with diabetes residing in a North London, community in the United Kingdom

BACKGROUND

There are marked ethnic differences in the susceptibility to the long-term diabetic vascular complications including sensory neuropathy. The vascular endothelial growth factor (VEGF) +405 (C/G) and -460 (T/C) polymorphisms are associated with retinopathy and possibly with nephropathy, however no information is available on their relationship with peripheral neuropathy. Therefore, we examined the prevalence of these VEGF genotypes in a multi-ethnic cohort of patients with diabetes and their relationship with evident peripheral diabetic neuropathy.

METHODS

In the current investigation, we studied 313 patients with diabetes mellitus of African-Caribbean, Indo-Asian and Caucasian ethnic origin residing in an inner-city community in London, United Kingdom attending a single secondary care centre. Genotyping was performed for the VEGF +405 and VEGF -460 polymorphisms using a pyrosequencing technique.

RESULTS

Forty-nine patients (15.6%) had clinical evidence of peripheral neuropathy. Compared to Caucasian patients, African-Caribbean and Indo-Asian patients had lower incidence of neuropathy (24.6%, 14.28%, 6.7%, respectively; P = 0.04). The frequency of the VEGF +405 GG genotype was more common in Indo-Asian patients compared to African-Caribbean and Caucasian patients (67.5%, 45.3%, 38.4%, respectively; p ≤ 0.02). The G allele was more common in patients with type 2 diabetes of Indo-Asian origin compared to African-Caribbean and Caucasian origin (p ≤ 0.02). There was no difference between the ethnic groups in VEGF -460 genotypes. The distributions of the VEGF +405 and VEGF -460 genotypes were similar between the diabetic patients with and without neuropathy.

CONCLUSIONS

In this cohort of patients, VEGF +405 and VEGF -460 polymorphisms were not associated with evident diabetic peripheral neuropathy, however an association was found between VEGF +405 genotypes and Indo-Asian which might have relevance to their lower rates of ulceration and amputation. This finding highlights the need for further investigation of any possible relationship between VEGF genotype, circulating VEGF concentrations and differential vulnerability to peripheral neuropathy amongst diabetic patients of different ethnic backgrounds.

The role of NOS2A -954G/C and vascular endothelial growth factor +936C/T polymorphisms in type 2 diabetes mellitus and diabetic nonproliferative retinopathy risk management

Type 2 diabetes mellitus (T2DM) remains one of the major health problems in Europe. Retinopathy is one of the major causes of morbidity in T2DM, strongly influencing the evolution and prognosis of these patients. In the last 2 decades, several studies have been conducted to identify the possible genetic susceptibility factors involved in the pathogenesis of the disease. However, there is little data related to the involvement of vascular endothelial growth factor (VEGF) and nitric oxide synthase (NOS) gene polymorphisms in the T2DM Caucasian population. The objective of this study was to identify a possible connection between NOS2A −954G/C (rs2297518) and VEGF +936C/T (rs3025039) polymorphisms and the risk of developing T2DM and nonproliferative diabetic retinopathy in a Caucasian population group. We investigated 200 patients diagnosed with T2DM and 208 controls. Genotypes were determined by multiplex polymerase chain reaction-restriction fragment length polymorphism. Statistical and comparative analyses (Fisher’s exact test) for dominant and recessive models of NOS2A −954G/C and VEGF +936C/T polymorphisms revealed an increased risk of T2DM (χ²=8.14, phi =0.141, P=0.004, odds ratio [OR] =2.795, 95% confidence interval [CI] =1.347–5.801; χ²=18.814, phi =0.215, P<0.001, OR =2.59, 95% CI =1.675–4.006, respectively). Also, comparative analysis for the recessive model (using Pearson’s chi-square test [χ²] and the phi coefficient [phi]) reveals that the variant CC genotype of NOS2A gene is more frequently associated with T2DM without retinopathy (χ²=3.835, phi =−0.138, P=0.05, OR =0.447, 95% CI =0.197–1.015). In conclusion, the results of the study place VEGF +936C/T polymorphisms among the genetic risk factor for T2DM, whereas NOS2A −954G/C polymorphisms act like a protective individual factor for nonproliferative retinopathy.

Association study of C936T polymorphism of the VEGF gene and the C242T polymorphism of the p22phox gene with diabetes mellitus type 2 and distal diabetic polyneuropathy

Even with long‑term glycemic control, diabetes mellitus type 2 (DM2) remains the predominant cause of diabetic neuropathy. Single nucleotide polymorphism (SNP) C936T of the vascular endothelial growth factor (VEGF) gene and the SNP C242T of the p22phox (CYBA) gene have been investigated in relation to DM2 and its complications. The aim of the present study was to investigate the association between these two SNPs and DM2, and also between the SNPs and the signs and symptoms of diabetic distal polyneuropathy. The DM2 group consisted of 98 individuals and the control group consisted of 104 individuals. The results demonstrated that there was no association between the different genotypes or alleles and increased risk of the disease (P>0.05). With SNP C242T, a significant association with body mass index between the CTxTT genotypes (P=0.043) was identified; and the greatest body mass indexes were among individuals with the TT genotype. An association between the degree of neuropathic symptoms and genotypic/allelic distribution of these polymorphisms was not observed. In conclusion, the investigated polymorphisms are not correlated with the risk of developing DM2.

Diabetic retinopathy: variations in patient therapeutic outcomes and pharmacogenomics

Diabetes and its microvascular complications in patients poses a significant challenge and constitutes a major health problem. When it comes to manifestations in the eye, each case of diabetic retinopathy (DR) is unique, in terms of the phenotype, genotype, and, more importantly, the therapeutic response. It is therefore important to identify factors that distinguish one patient from another. Personalized therapy in DR is a new trend aimed at achieving maximum therapeutic response in patients by identifying genotypic and phenotypic factors that may result in less than optimal response to conventional therapy, and consequently, lead to poorer outcome. With advances in the identification of these genetic markers, such as gene polymorphisms and human leucocyte antigen associations, as well as development of drugs that can target their effects, the future of personalized medicine in DR is promising. In this comprehensive review, data from various studies have been analyzed to present what has been achieved in the field of pharmacogenomics thus far. An insight into future research is also provided.

Meta-analysis of association between the -2578C/A polymorphism of the vascular endothelial growth factor and retinopathy in type 2 diabetes in Asians and Caucasians

BACKGROUND AND OBJECTIVES

Vascular endothelial growth factor (VEGF) has been shown to play an important role in the development and progress of diabetic retinopathy (DR). A number of case-control studies focused on the association between VEGF -2578C/A and risk for DR. But the results were not always consistent, so we performed a meta-analysis to evaluate the precise association between this variant and risk for DR.

METHODS

All publications on the association between VEGF -2578C/A polymorphism and DR were searched in the following electronic databases: PubMed, Embase, the Cochrane Library and Chinese Biomedical Literature Database, with the last report up to January 2013. This meta-analysis was assessed by Review Manager 5.1.

RESULTS

A total of 6 studies were involved in this meta-analysis, including 835 cases and 867 controls. Overall, we found a significant association between this polymorphism and DR (A vs. C: OR=1.49, 95% CI=1.26-1.77, p<0.00001; AA vs. CA+CC: OR=1.26, 95% CI=0.94-1.68, p=0.12; AA+CA vs. CC: OR=1.56, 95% CI=1.27-1.91, p<0.00001; AA vs. CC: OR=1.67, 95% CI=1.20-2.32, p=0.003; CA vs. CC: OR=1.51, 95% CI=1.21-1.87, p=0.0002), but we did not find any significant association in Caucasians in subgroup analysis. The results were not materially altered after the studies which did not fulfill the Hardy-Weinberg equilibrium were excluded.

CONCLUSION

Our meta-analysis supports the association between the VEGF -2578C/A polymorphism and DR, but not in the Caucasian population.

Genetics in diabetic retinopathy: current concepts and new insights

There is emerging evidence which indicates the essential role of genetic factors in the development of diabetic retinopathy (DR). In this regard it should be highlighted that genetic factors account for 25-50% of the risk of developing DR. Therefore, the use of genetic analysis to identify those diabetic patients most prone to developing DR might be useful in designing a more individualized treatment. In this regard, there are three main research strategies: candidate gene studies, linkage studies and Genome-Wide Association Studies (GWAS). In the candidate gene approach, several genes encoding proteins closely related to DR development have been analyzed. The linkage studies analyze shared alleles among family members with DR under the assumption that these predispose to a more aggressive development of DR. Finally, Genome-Wide Association Studies (GWAS) are a new tool involving a massive evaluation of single nucleotide polymorphisms (SNP) in large samples. In this review the available information using these three methodologies is critically analyzed. A genetic approach in order to identify new candidates in the pathogenesis of DR would permit us to design more targeted therapeutic strategies in order to decrease this devastating complication of diabetes. Basic researchers, ophthalmologists, diabetologists and geneticists should work together in order to gain new insights into this issue.

The associations between VEGF gene polymorphisms and diabetic retinopathy susceptibility: a meta-analysis of 11 case-control studies

AIMS. Published data on the associations of VEGF polymorphisms with diabetic retinopathy (DR) susceptibility are inconclusive. A systematic meta-analysis was undertaken to clarify this topic. METHODS. Data were collected from the following electronic databases: PubMed, Embase, OVID, Web of Science, Elsevier Science Direct, Excerpta Medica Database (EMBASE), and Cochrane Library with the last report up to January 10, 2014. ORs and 95% CIs were calculated for VEGF-2578C/A (rs699947), -1154G/A (rs1570360), -460T/C (rs833061), -634G>C (rs2010963), and +936C/T (rs3025039) in at least two published studies. Meta-analysis was performed in a fixed/random effect model by using the software STATA 12.0. RESULTS. A total of 11 studies fulfilling the inclusion criteria were included in this meta-analysis. A significant relationship between VEGF+936C/T (rs3025039) polymorphism and DR was found in a recessive model (OR = 3.19, 95% CI = 1.20-8.41, and P(z) = 0.01) in Asian and overall populations, while a significant association was also found between -460T/C (rs833061) polymorphism and DR risk under a recessive model (OR = 2.12, 95% CI = 1.12-4.01, and P(z) = 0.02). CONCLUSIONS. Our meta-analysis demonstrates that +936C/T (rs3025039) is likely to be associated with susceptibility to DR in Asian populations, and the recessive model of -460T/C (rs833061) is associated with elevated DR susceptibility.

Association of -2549 insertion/deletion polymorphism of vascular endothelial growth factor with breast cancer in North Indian patients

AIMS

The aim of the present study was to assess the role of the vascular endothelial growth factor (VEGF) -2549 insertion/deletion (I/D) polymorphism in susceptibility to sporadic breast cancer.

METHODS

DNA samples of 94 breast cancer patients and 94 unrelated healthy control individuals with matched age and gender from the same geographical region of Punjab, North West India were screened for the -2549 I/D polymorphism. Serum VEGF-C (sVEGF-C) levels of breast cancer patients and healthy controls were measured using an enzyme-linked immunosorbent assay.

RESULTS

The frequency of the II, ID, and DD genotype was 23.40 versus 10.64%, 48.94 versus 52.13%, and 27.66 versus 37.23%, in patients and controls, respectively. A statistically significant difference was observed for genotype distribution among the patients and controls (χ(2)=6.039, p=0.049). There was a significant increase in the I allele frequency in the patients as compared with controls (47.86 versus 36.70%, p=0.028). The sVEGF-C levels were also considerably higher in patients as compared to healthy controls (p<0.01).

CONCLUSIONS

The VEGF -2549 I/D polymorphism has a role in the susceptibility to breast cancer in the Amritsar region of Punjab, India.

Vascular endothelial growth factor (VEGF-a) in Fabry disease: association with cutaneous and systemic manifestations with vascular involvement

INTRODUCTION

Fabry disease is an X-linked inherited metabolic disorder characterized by the deficiency of lysosomal α-galactosidase A enzyme. This leads to the accumulation, into lysosomes through the body, of glycosphingolipids, mainly Gb3. Skin involvement and progressive multi-organ failure are usually observed. Endothelium is the preferential target of the Gb3 storage that determines endothelial dysfunction and vasculopathy leading to the clinical manifestations of the disease. The serum levels of Vascular Endothelial Growth Factor-A (VEGF-A), a specific endothelial cell mitogen, were analyzed in Fabry patients to explore a possible association to the clinical manifestations with vascular involvement.

METHODS

Thirty-five patients with a biochemical and genetic diagnosis of Fabry disease, along with an age-gender-matched healthy control group, were enrolled. Serum samples were collected and analyzed by ELISA. The genetic mutations, the specific organ dysfunction, and the cardiovascular risk factors such as dyslipidaemia, diabetes, smoking habits and hypertension were evaluated in Fabry patients.

RESULTS

The mean serum level of VEGF-A in Fabry patients group was significantly higher than in the control group (P=0.006). A statistical significant association, between VEGF-A levels and the skin manifestation including angiokeratomas, sweating abnormalities and Fabry Facies was found. An association was also found between high VEGF-A and specific GLA mutations, the male gender, the renal and neurological manifestations, the presence of eye vessels tortuosity, smoking habit and hypertension.

CONCLUSIONS

We detected increased VEGF-A levels in patients with Fabry disease compared to the controls, and we hypothesized that this could be a response to the vascular damage characterising this lysosomal disorder. However, further studies are necessary to clarify the role of VEGF-A in Fabry.

Impact of VEGF polymorphisms on the severity of peripheral artery disease in diabetic patients

OBJECTIVE

To determine the potential genotype vascular endothelial growth factor (VEGF) gene differences in diabetic patients with peripheral arterial disease (PAD), which might be associated with different stages of the vascular disease.

METHODS

A study was conducted with type 2 diabetic patients with PAD [n = 70; 32 intermittent claudication and 38 critical limb ischaemia (CLI)]. Genotyping of the VEGF gene insertion/deletion - 2549, - 2578 C/A and +405 G/C polymorphisms was done in both groups and correlated them with the severity of PAD. We compared serum VEGF levels in both groups.

RESULTS

There was a higher frequency of +405 CC and - 2578 CC genotypes in claudication group [(31.3% vs. 5.4%, p = 0.01) and (37.5% vs. 15.8%, p = 0.05), respectively]. The presence of +405 GG and - 2578 AA genotypes was more common among CLI patients [(57.8% vs. 37.5%, p = 0.01) and (42.1% vs. 18.8%, p = 0.05), respectively]. There were higher serum VEGF levels in patients with CLI (p = 0.029).

CONCLUSIONS

We found preliminary evidence regarding the association between VEGF polymorphisms and different stages of PAD in diabetic patients.