VEGF gene variability and type 1 diabetes: evidence for a protective role

Cigarette smoke modulates binding of the transcription factor MZF1 to the VEGF promoter and regulates VEGF expression in dependence of genetic variation SNP 405

BACKGROUND

Vascular endothelial growth factor (VEGF) affects carcinogenesis of the upper aerodigestive tract. Cigarette smoke (CSE) influences VEGF-gene regulation. The single nucleotide polymorphism +405 G/C (SNP +405 G/C) and the transcriptional factor (TF) myeloid zinc finger 1 (MZF1) are endogenic regulators of the VEGFpromoter as the polymorphism 405 potentially affects binding of the transcription factor MZF1. Therefore, this in vitro study analysed cancer cells of the upper aerodigestive tract after CSE incubation concerning MZF1-binding specificity and VEGF expression in dependency of VEGF polymorphism +405 G/C compared to wild type (wt).

METHODS

In human alveolar epithelial-like type-II cells (A549) and oral squamous cell cancer cells (HNSCCUM-02T) SNP +405 G/C- and MZF1-dependent VEGF promoter activity and VEGF expression were analysed by qRT-PCR and Western blot after incubation with 10% CSE. Temporary knock-down of MZF1 was performed using siRNA. MZF1 binding was analysed by Co-Chromatin-Immunoprecipitation (Co-ChiP) (each test n = 3).

RESULTS

We found a stronger MZF1 binding to VEGF polymorphism 405 in A549 cells (P < .05) compared to HNSCCUM-02T cells (P = .02), where MZF1 binding was reduced. MZF1 knock out reduced VEGF promoter activity in HNSCCUM-02T cells, showing the relevance of the factor for transcriptional activation of the VEGF promoter. Finally, we found that CSE increases promoter activity in both cell lines and no significant differences between the two analysed polymorphisms concerning their activating capacity.

CONCLUSION

In summary, both VEGF promoter polymorphisms are similar effective in terms of transcriptional activity, and MZF1 is a transcriptional activator of VEGF promoter. Moreover, cigarette smoke increases MZF1 binding of VEGF-promoter and directly affects VEGF-gene regulation.

Gene polymorphisms of VEGF and VEGFR2 are associated with the severity of Hashimoto's disease and the intractability of Graves' disease, respectively

Vascular endothelial growth factor (VEGF) is one of main regulators of angiogenesis that functions by binding to its receptors, including VEGF receptor (VEGFR) 2. There are few data available regarding the association between VEGF and VEGFR polymorphisms and the susceptibility to and prognosis of autoimmune thyroid diseases (AITDs). To elucidate this association, we genotyped four functional VEGF and two VEGFR2 polymorphisms and measured serum VEGF levels. In the four functional VEGF polymorphisms, the frequencies of the I carrier and I allele of VEGF -2549 I/D, which has lower activity, were higher in patients with severe HD than in those with mild HD. In the two functional VEGFR2 polymorphisms, the frequency of the rs2071559 CC genotype, which has higher activity, was higher in patients with intractable GD than in controls, and the proportion of GD patients with larger goiters was higher in those with the CC genotype. Moreover, the frequency of the rs1870377 TT genotype with higher activity was higher in patients with intractable GD than in those with GD in remission. Combinations of VEGF and VEGFR2 polymorphisms with stronger interactions were associated with the intractability of GD. Serum VEGF levels were higher in HD and AITD patients than those in controls. In conclusion, VEGF polymorphisms with lower activity were associated with the severity of HD, while VEGFR2 polymorphisms and the combinations of VEGF and VEGFR2 polymorphisms, which have stronger interactions, were associated with the intractability of GD. VEGF and VEGFR2 polymorphisms were associated with HD severity and GD intractability, respectively.

Interactions between the vascular endothelial growth factor gene polymorphism and life events in susceptibility to major depressive disorder in a Chinese population

BACKGROUND

Recent studies suggest that vascular endothelial growth factor (VEGF) is involved in the development of major depressive disorder. The aim of this study is to investigate the interaction between vascular endothelial growth factor (VEGF) polymorphism (+405G/C, rs2010963) and negative life events in the pathogenesis of major depressive disorder (MDD).

METHODS

DNA genotyping was performed on peripheral blood leukocytes in 274 patients with MDD and 273 age-and sex-matched controls. The frequency and severity of negative life events were assessed by the Life Events Scale (LES). A logistics method was employed to assess the gene-environment interaction (G×E).

RESULTS

Differences in rs2010963 genotype distributions were observed between MDD patients and controls. Significant G×E interactions between allelic variation of rs2010963 and negative life events were observed. Individuals carrying the C alleles were susceptible to MDD only when exposed to high-negative life events.

CONCLUSIONS

These results indicate that interactions between the VEGF rs2010963 polymorphism and environment increases the risk of developing MDD.

Plasma VEGF-related polymorphisms are implied in autoimmune thyroid diseases

Autoimmune thyroid diseases (AITD), including Graves' disease (GD) and Hashimoto thyroiditis (HT), are complex multifactorial diseases. Vascular endothelial growth factor (VEGF) is implicated in various inflammatory diseases, especially autoimmune diseases. Our aim was to elucidate the relationships between plasma VEGF levels and four genome-wide association study-identified single nucleotide polymorphisms (SNPs) related to VEGF with AITD in Tunisian patients. A total of 364 healthy controls and 389 patients with AITD were genotyped for the SNPs rs6921438, rs4416670, rs6993770 and rs10738760. Levels of thyroid hormones and antibodies were quantified simultaneously with plasma VEGF after a period of six months of treatment. We found that the minor alleles of rs10738760 and rs6921438 are associated with the presence of GD. A allele of rs10738760 polymorphism is associated with increased plasma levels of free tri-iodothyronin (FT3) while no relationship was found with circulating VEGF plasma levels after six months of treatment. We also showed that the T allele of rs4416670 polymorphism was associated with increased risk of hyperthyroidism in patients treated for six months, independently of their initial diagnosis. There was no significant association between the SNPs and the risk for HT compared with controls. This study shows that AITD are influenced by 3 SNPs linked to VEGF circulating levels. Whereas rs10738760 appeared specific to GD and FT3 production after six months of treatment, rs6921438 and rs4416670 were implicated in the risk for GD. This study opens new ways to test pharmacogenomics concepts in the future especially in GD in which recurrence prognosis is still challenging.

Investigating the role of angiogenesis in systemic lupus erythematosus

OBJECTIVE

We aimed to elucidate the roles of six pro-angiogenic factors, namely, basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), placental growth factor (PlGF), hepatocyte growth factor (HGF), transforming growth factor-beta (TGF-beta) and tumor necrosis factor-alpha (TNF-alpha), in the pathogenesis of systemic lupus erythematosus (SLE).

METHODS

A group of 75 patients with SLE and a control group of 40 healthy volunteers were recruited. Angiogenic factors were tested through enzyme-linked immunosorbent assay (ELISA) measurement. The angiogenic activities of the patients with SLE and the healthy controls were assessed and a correlation analysis of these angiogenic factors was conducted.

RESULTS

A much higher level of angiogenic activity was shown in the serum of patients with SLE than that of the healthy controls, yet no statistically significant difference was found in the angiogenic activities of active SLE and inactive SLE. Serum VEGF level in the active SLE group was significantly higher than that in the control group and the inactive SLE group, and serum HGF level was strongly positively correlated with VEGF in all SLE groups; meanwhile, there was also a statistically significant positive correlation between TNF-alpha and VEGF in all SLE groups. There was a statistically significant positive correlation between serum VEGF level and bFGF level in the active SLE group. There was a slightly negative correlation between serum HGF level and TGF-beta level in the SLE group, but this negativity did not reach the significance level. Likewise, positive correlation was also shown in the serum VEGF level and PlGF level, yet not in bFGF with PlGF.

CONCLUSION

Circulating serum angiogenic cytokines may be disease markers of SLE activity. Anti-angiogenic agents such as thalidomide and endogenous angiogenesis inhibitors such as endostatin are potentially effective and promising therapies in the treatment of SLE.

Vascular endothelial growth factor (VEGF) gene polymorphisms and breast cancer risk in Punjabi population from North West India

The purpose of this study was to evaluate the association of seven VEGF promoter polymorphisms with breast cancer risk in Punjabi population from North West India. We screened DNA samples of 102 sporadic breast cancer patients and 102 unrelated healthy, gender, and age-matched individuals for seven VEGF promoter polymorphisms [-417 C/T (rs833062), -172 C/A (rs59260042), -165 C/T (rs79469752), -160 C/T, -152 G/A (rs13207351), -141 A/C (rs28357093) and -116 G/A (rs1570360)] by direct sequencing. The frequency of GG, GA, and AA genotype of -152 G/A polymorphism was 26.47 vs 38.34%, 46.08 vs 51.96%, and 27.45 vs 9.80%, in patients and controls, respectively. VEGF -152 AA genotype was significantly associated with increased risk for breast cancer (OR = 4.04, 95%CI, 1.69-9.68, p = 0.001; recessive model OR = 3.48, 95%CI, 1.59-7.63, p = 0.001). For VEGF -116 G/A polymorphism, G and A allele frequencies were 65.2 vs 76.47% and 34.8 vs 23.53% in patients and controls, respectively. Individuals having -116 AA genotype (OR = 3.40; 95%CI, 1.24-9.37; p = 0.014) and A allele (OR = 1.73; 95%CI, 1.12-2.67; p = 0.012) were associated with increased risk for breast cancer. VEGF -165 C/T and -141 A/C polymorphisms were associated with reduced risk for breast cancer. There was significantly decreased frequency of CT genotype (4.90 vs 18.63%; p = 0.002) and T allele (2.45 vs 9.31%; p = 0.003) of -165 C/T polymorphism among breast cancer patients as compared to controls. VEGF -141 A and C allele frequency were 96.57 vs 91.18% and 3.43 vs 8.82% in patients and controls, respectively. Significant reduced risk for breast cancer was observed with AC genotype (OR = 0.34, 95%CI, 0.14-0.86; p = 0.019) and C allele (OR = 0.37; 95%CI, 0.15-0.89; p = 0.023) of -141 A/C polymorphism. We did not observe association of VEGF -417 T/C, -172 C/A, -160 C/T polymorphisms with breast cancer risk in the studied subjects (p > 0.05). The VEGF -152 G/A and -116 G/A polymorphisms were found to be significantly associated with increased risk for breast cancer while -165 C/T and -141 A/C polymorphisms were found to be associated with decreased risk for breast cancer in Punjabi population from North West India.

Genome-wide association study of urinary albumin excretion rate in patients with type 1 diabetes

AIMS/HYPOTHESIS

An abnormal urinary albumin excretion rate (AER) is often the first clinically detectable manifestation of diabetic nephropathy. Our aim was to estimate the heritability and to detect genetic variation associated with elevated AER in patients with type 1 diabetes.

METHODS

The discovery phase genome-wide association study (GWAS) included 1,925 patients with type 1 diabetes and with data on 24 h AER. AER was analysed as a continuous trait and the analysis was stratified by the use of antihypertensive medication. Signals with a p value <10(-4) were followed up in 3,750 additional patients with type 1 diabetes from seven studies.

RESULTS

The narrow-sense heritability, captured with our genotyping platform, was estimated to explain 27.3% of the total AER variability, and 37.6% after adjustment for covariates. In the discovery stage, five single nucleotide polymorphisms in the GLRA3 gene were strongly associated with albuminuria (p < 5 × 10(-8)). In the replication group, a nominally significant association (p = 0.035) was observed between albuminuria and rs1564939 in GLRA3, but this was in the opposite direction. Sequencing of the surrounding genetic region in 48 Finnish and 48 UK individuals supported the possibility that population-specific rare variants contribute to the synthetic association observed at the common variants in GLRA3. The strongest replication (p = 0.026) was obtained for rs2410601 between the PSD3 and SH2D4A genes. Pathway analysis highlighted natural killer cell mediated immunity processes.

CONCLUSIONS/INTERPRETATION

This study suggests novel pathways and molecular mechanisms for the pathogenesis of albuminuria in type 1 diabetes.

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.

Short-term overexpression of VEGF-A in mouse beta cells indirectly stimulates their proliferation and protects against diabetes

AIMS/HYPOTHESIS

Vascular endothelial growth factor (VEGF) has been recognised by loss-of-function experiments as a pleiotropic factor with importance in embryonic pancreas development and postnatal beta cell function. Chronic, nonconditional overexpression of VEGF-A has a deleterious effect on beta cell development and function. We report, for the first time, a conditional gain-of-function study to evaluate the effect of transient VEGF-A overexpression by adult pancreatic beta cells on islet vasculature and beta cell proliferation and survival, under both normal physiological and injury conditions.

METHODS

In a transgenicmouse strain, overexpressing VEGF-A in a doxycycline-inducible and beta cell-specific manner, we evaluated the ability of VEGF-A to affect islet vessel density, beta cell proliferation and protection of the adult beta cell mass from toxin-induced injury.

RESULTS

Short-term VEGF-A overexpression resulted in islet hypervascularisation, increased beta cell proliferation and protection from toxin-mediated beta cell death, and thereby prevented the development of hyperglycaemia. Extended overexpression of VEGF-A led to impaired glucose tolerance, elevated fasting glycaemia and a decreased beta cell mass.

CONCLUSIONS/INTERPRETATION

Overexpression of VEGF-A in beta cells time-dependently affects glycometabolic control and beta cell protection and proliferation. These data nourish further studies to examine the role of controlled VEGF delivery in (pre)clinical applications aimed at protecting and/or restoring the injured beta cell mass.

Pre-transplant signal induction for vascularisation in human islets

Human islet transplant success is partially impaired by slow revascularisation. Our study investigated the potential for rotational cell culture (RC) of human islets combined with thiazolidinedione (TZD) stimulation of peroxisome proliferator-activated receptor gamma (PPARγ) to upregulate vascular endothelial growth factor (VEGF) expression in the islets. Four groups of human islets were studied: static culture (SC) with and without 25 mmol/L TZD and RC with and without 25 mmol/L TZD. These were assessed for insulin secretion and soluble VEGF-A release. Both proteins were quantified by enzyme-linked immunosorbent assay (ELISA), supported with qualitative immunofluorescence staining. RC + TZD increased insulin secretion by >20% (p < 0.05-0.001) in response to 16.7 mmol/L glucose and 16.7 mmol/L glucose + 10 mmol/L theophylline (G + T). This effect was seen at all time intervals compared with SC and without addition of TZD. Soluble VEGF-A release was significantly augmented by RC and TZD exposure with an increased effect of >30% (p < 0.001) at 72 h under both SC and RC conditions. RC supplemented with a TZD enhances and prolongs the release of insulin and soluble VEGF-A by isolated human islets.

Common polymorphisms in angiogenesis

A wide variety of diseases have a significant genetic component, including major causes of morbidity and mortality in the western world. Many of these diseases are also angiogenesis dependent. In humans, common polymorphisms, although more subtle in effect than rare mutations that cause Mendelian disease, are expected to have greater overall effects on human disease. Thus, common polymorphisms in angiogenesis-regulating genes may affect the response to an angiogenic stimulus and thereby affect susceptibility to or progression of such diseases. Candidate gene studies have identified several associations between angiogenesis gene polymorphisms and disease. Similarly, emerging pharmacogenomic evidence indicates that several angiogenesis-regulating polymorphisms may predict response to therapy. In contrast, genome-wide association studies have identified only a few risk alleles in obvious angiogenesis genes. As in other traits, regulatory polymorphisms appear to dominate the landscape of angiogenic responsiveness. Rodent assays, including the mouse corneal micropocket assay, tumor models, and a macular degeneration model have allowed the identification and comparison of loci that directly affect the trait. Complementarity between human and animal approaches will allow increased understanding of the genetic basis for angiogenesis-dependent disease.

FTY720 protects cardiac microvessels of diabetes: a critical role of S1P1/3 in diabetic heart disease

Background: Diabetes is associated with an increased risk of cardiac microvascular disease. The mechanisms by which this damage occurs are unknown. However, research suggests that signaling through the sphingosine-1-phosphates receptor 1 and 3 (S1P1/3) by FTY720, a sphiongolipid drug that is structually similar to SIP, may play a role in the treatment on cardiac microvascular dysfunction in diabetes. We hypothesized that FTY720 might exert the cardioprotective effects of S1P1 and S1P3 viaprotein kinase C-beta (PKCβ II) signaling pathway.

Methodology/Principal Findings: Transthoracic echocardiography was performed to detect the change of cardiac function. Scanning and transmission electron microscope with lanthanum tracer were used to determine microvascular ultrastructure and permeability in vivo. Apoptosis was detected by TUNEL and CD31 dual labeling in paraffin-embedded sections. Laser capture miscrodissection was used to assess cardiac micovascular endothelial cells (CMECs) in vivo. RT-PCR and Western blot analysis were used to determine the mRNA levels and protein expression of S1P1, S1P3, and PKCβ II. In the diabetic rats vs. controls, cardiac capillaries showed significantly higher density; CD31 positive endothelial cells were significantly reduced; the apoptosis index of cardiac endothlial cells was significantly higher. And FTY720 could increase the expressional level of S1P1 and boost S1P3 trasnslocation from membrane to nuclear, then ameliorate cardiac microvascular barrier impairment and pathologic angiogenesis induced by diabetes. In addition, overexpression of PKCβ II significantly decreased the protective effect of FTY720.

Conclusions: Our study represents that the deregulation of S1P1 and S1P3 is an important signalresponsible for cardiac microvascular dysfunction in diabetes. FTY720 might be competent to serve as a potential therapeutic approach for diabetic heart disease through ameliorating cardiac microvascular barrier impairment and pathologic angiogenesis, which might be partly dependent on PKCβII-mediated signaling pathway.

Vascular endothelial growth factor polymorphisms increase the risk of developing Graves' disease

BACKGROUND

Graves' disease (GD) is a consequence of genetic and environmental factors. Vascular endothelial growth factor (VEGF) is a strong angiogenic and mitogenic factor, which plays a key role in lymphocyte infiltration, and hypervascularization in the thyroid gland of patients with GD.

AIM

The aim of this study is to investigate the relationship between GD and A-2578C, T-460C and G+405C single nucleotide polymorphisms (SNPs) of VEGF gene, as well as to evaluate whether there are any relationships between genotypes and some clinical/laboratory parameters of GD.

METHODS

We analyzed the genotype and allele distributions of the above mentioned SNPs in 167 patients with established GD diagnosis and 203 healthy controls by real-time PCR combined with melting curve analysis using fluorescence-labeled hybridization probes.

RESULTS

The distribution of VEGF A-2578C and T-460C genotypes and allele frequencies in control and GD groups were not significantly different. With regard to the +405 polymorphism, the frequency of C allele was 1.8-fold increased in GD patients compared to controls, and the CC genotype was associated with a 4.6-fold increased disease risk. There was no relationship between some clinical/laboratory parameters with G+405C polymorphism. However, in -2578C allele carrying GD patients the anti-thyroid antibody levels were increased according to wild homozygous. Additionally, -2578C and -460T alleles were related with early (at age before 40) disease onset.

CONCLUSION

VEGF +405 polymorphism may be a risk factor for GD, while the -2578 SNP is related with increased autoantibody production.

The association of single nucleotide polymorphism within vascular endothelial growth factor gene with systemic lupus erythematosus and lupus nephritis

There were no statistically significant difference in allele and genotype frequency of the polymorphisms within the vascular endothelial growth factor (VEGF) gene (-460 and +405) between 193 systemic lupus erythematosus patients and 234 healthy controls. However, the +405 GG was significantly associated with lupus nephritis (LN) patients with low VEGF mRNA expression and LN with end-stage renal disease.

Association of hypoxia inducible factor-1 alpha gene polymorphism with both type 1 and type 2 diabetes in a Caucasian (Hungarian) sample

Background

Hypoxia inducible factor-1 alpha (HIF-1α) is a transcription factor that plays an important role in neo-vascularisation, embryonic pancreas beta-cell mass development, and beta cell protection. Recently a non synonymous single nucleotide polymorphism (g.C45035T SNP, rs11549465) of HIF-1α gene, resulting in the p.P582S amino acid change has been shown to be associated with type 2 diabetes (T2DM) in a Japanese population. Our aim was to replicate these findings on a Caucasian (Hungarian) population, as well as to study whether this genetic effect is restricted to T2DM or can be expanded to diabetes in general.

Methods

A large Caucasian sample (N = 890) was recruited including 370 T2DM, 166 T1DM and 354 healthy subjects. Genotyping was validated by two independent methods: a restriction fragment analysis (RFLP) and a real time PCR using TaqMan probes. An overestimation of heterozygotes by RFLP was observed as a consequence of a nearby SNP (rs34005929). Therefore genotyping results of the justified TaqMan system were accepted. The measured genotype distribution corresponded to Hardy-Weinberg equilibrium (P = 0.740)

Results

As the TT genotype was extremely rare in the population (0.6% in clinical sample and 2.5% in controls), the genotypes were grouped as T absent (CC) and T present (CT and TT). Genotype-wise analysis showed a significant increase of T present group in controls (24.0%) as compared to patients (16.8%, P = 0.008). This genetic effect was demonstrated in the separated samples of type 1 (15.1%, P = 0.020), and also in type 2 (17.6%, P = 0.032) diabetes. Allele-wise analysis gave identical results showing a higher frequency of the T allele in the control sample (13.3%) than in the clinical sample (8.7%, P = 0.002) with similar results in type 1 (7.8%, P = 0.010) and type 2 (9.1%, P = 0.011) diabetes. The odds ratio for diabetes (either type 1 or 2) was 1.56 in the presence of the C allele.

Conclusion

We confirmed the protective effect of a rare genetic variant of HIF-1α gene against type 2 diabetes in a Caucasian sample. Moreover we demonstrated a genetic contribution of the same polymorphism in type 1 diabetes as well, supporting a possible overlap in pathomechanism for T2DM and a T1DM.

VEGF genetic variability is associated with increased risk of developing Alzheimer's disease

Specific polymorphisms within the vascular endothelial growth factor (VEGF) gene promoter region are of particular interest: VEGF variability has been associated with increased risk of developing a wide variety of disorders from diabetes to neurodegenerative diseases, suggesting functions not confined to its originally described vascular effects. A hypothetical loss of the VEGF-mediated neuroprotective effect has been proposed as a cause of neurodegenerative disorders. An impaired regulation of VEGF expression has been also reported in Alzheimer's disease (AD) pathogenesis. Recently, VEGF gene promoter polymorphisms have been associated with an increased risk for AD in the Italian population. Conversely, two subsequent studies failed to find a positive association between VEGF variability and greater risk for AD. To better clarify this issue, a meta-analysis of all published association studies has been performed. Overall, polymorphic variants within VEGF gene promoter confer greater risk for AD at least in the Italian population; the meta-analysis provides evidence of a role of the functional variant C(-2578)A in the pathogenesis of the disease, although the pooled odds ratio obtained represents a modest effect. These findings provide new evidence for an additional candidate genetic risk factor for AD that can be tested in further studies.

Novel single nucleotide polymorphism of the VEGF gene as a risk predictor for gastroduodenal ulcers

BACKGROUND AND AIM

The gastroduodenal ulcer (GDU) mostly develops on the lesser curvature side of stomach and the anterior wall of duodenal bulb, irrespective of the etiologies including Helicobacter pylori infection, non-steroidal anti-inflammatory drugs, alcohol, etc. However, a clear explanation as to why ulcers are prevalent in these areas has still not been given. The current study was designed to evaluate whether the vascular endothelial growth factor (VEGF) polymorphism could predict susceptibility to GDU through deranged angiogenic activities.

METHODS

A large scale case-control study based on known single nucleotide polymorphisms (SNP) of VEGF and another case control study based on the novel SNP of VEGF was performed through the SNP-IT assay using the SNP stream 25 k system. A site-directed mutagenesis and functional assay was executed to document the biological effect of a novel VEGF SNP on angiogenesis.

RESULTS

Even though the case-control study between non-ulcer dyspepsia (NUD) and gastric ulcer (GU) patients was done in 10 SNP of the VEGF gene including -2488C/T, -634G/C, -7C/T, 3436G/C, 6112C/A, 6894C/T, 9374G/A, 9812C/T, 13128C/T, and 13553C/T, the analysis showed no statistically significant association between NUD and GU. Denaturing high-performance liquid chromatography analysis could identify two novel SNP of the VEGF gene, -1780T/C and IVS-99 G/C, among which -1780T/C showed a very strong association between NUD and GDU, presenting with OR=2.93 on codominant analysis (P<0.001), OR=8.62 on dominant analysis (P<0.001), and OR=3.21 on recessive analysis (P<0.001). The promoter assay using a site-directed mutagenesis and in vitro angiogenesis assay showed repressed transcription of the VEGF gene in gastric epithelial cells and defective tube formation in endothelial cells, both transfected with a plasmid containing -1780C/C mutant of VEGF gene.

CONCLUSION

The novel VEGF polymorphism -1780T/C could significantly predict the predisposition to GDU after the exposure to etiologic risks, based on defective angiogenic activity.

Role of VEGF gene variability in longevity: A lesson from the Italian population

Vascular endothelial growth factor (VEGF) gene polymorphisms have been associated with an increased risk of developing a wide variety of disorders from diabetes to neurodegenerative diseases suggesting functions not confined to its vascular effects originally described. Based on the VEGF protective roles undisclosed in pathological conditions, we evaluate whether VEGF variability might be a determinant also for longevity. Four polymorphisms (-2578C/A, -1190G/A, -1154G/A and -634G/C) within the VEGF gene promoter region in 490 unrelated Italian healthy subjects have been analysed. Significant changes of allele, genotype (-2578/AA versus -2578/CC: OR=2.08, p=0.007; -1190/AA versus -1190/GG: OR=2.01, p=0.011) and haplotype (AAGG: 10.4% versus 14.9%, p=0.03) frequency distributions were observed between young/elderly (25-84 years old) and long-lived (85-99 years old) subjects. These results suggest that VEGF gene variability can be inserted among the genetic factors influencing the lifespan.

Targeting the retinal microcirculation to treat diabetic sight problems

Diabetic retinopathy is a secondary complication of hyperglycemia caused by diabetes mellitus. The damage to the retina can ultimately cause vision loss as a result of increased capillary permeability and angiogenesis. Recent progress in the understanding of the mediators that drive angiogenesis, as well as the phenotypes of cells that are involved in this process, has provided a multitude of targets for pharmacologic intervention. This review presents the inhibitors of the biochemical processes that are at the root of diabetic retinopathy (i.e., non-enzymatic glycosylation of biomolecules, oxidative stress, activation of aldose reductase and activation of protein kinase C by formation of diacylglycerol) in addition to the inhibitors of the mechanical damage (i.e., increased vascular permeability, capillary occlusion and neovascularization).

Recent advancement of understanding pathogenesis of type 1 diabetes and potential relevance to diabetic nephropathy

Type 1 diabetes mellitus is an autoimmune disease characterized by progressive destruction of pancreatic beta cells by genetic and environmental factors which leads to an absolute dependence of insulin for survival and maintenance of health. Although the majority of mechanisms of beta cell destruction remain unclear, many molecules, including proinflammatory cytokines and chemokines such as tumor necrosis factor alpha and monocyte chemoattractant protein-1, are implicated in the development of beta cell damage. Furthermore, beta cell destruction is enhanced by the Th1 and Th17 subsets of CD4+ T cells. In contrast, there are mechanisms involved in the maintenance of peripheral tolerance by regulatory T cells, the function of which depends on the pleiotropic cytokine transforming growth factor beta. Development and progression of renal injuries in patients with diabetic nephropathy are also associated with several growth factors and proinflammatory cytokines, including tumor necrosis factor alpha, insulin-like growth factor-1, monocyte chemoattractant protein-1, vascular endothelial growth factor, and transforming growth factor beta. Although the pathogenic mechanisms underlying type 1 diabetes and diabetic nephropathy are principally different, i.e., autoimmunity and inflammation, some common factors, including susceptibility genes and proinflammatory cytokines, are involved in both mechanisms, including infiltrating cell recruitment, upregulation of other cytokines and chemokines, or apoptosis.

The role of vascular endothelial growth factor (VEGF) in inflammatory bowel disease

BACKGROUND

Vascular endothelial growth factor (VEGF) is a candidate susceptibility gene to inflammatory bowel disease (IBD), both from a functional as well as genetic perspective. Moreover, serum VEGF (sVEGF) levels are increased in IBD and correlate with disease activity. Both VEGF expression and sVEGF levels may be influenced by VEGF gene polymorphisms.

AIMS

To study VEGF polymorphisms in IBD susceptibility and their impact on sVEGF levels.

METHODS

Four functional VEGF polymorphisms (-C2578A, -G1154A, -G634C, and C936T) were genotyped in two independent cohorts (cohort 1: 372 IBD trios; cohort 2: 452 unrelated IBD patients, 271 healthy controls [HC]; and 93 patients with non-IBD gastrointestinal inflammation [non-IBD GI]), using polymerase chain reaction with restriction fragment length polymorphism and TaqMan minor groove binding. Phenotypical data on all patients as well as sVEGF levels were correlated with the genetic data.

RESULTS

Both the VEGF genotype and haplotype frequencies did not differ between IBD patients and controls, and no distortion of transmission was observed. sVEGF levels were increased in IBD but also in non-IBD GI patients, compared with HC, and were only influenced by VEGF polymorphisms in patients with Crohn's disease (-G1154A genotype and -2578/-1154/-634 AAG promoter haplotype).

CONCLUSIONS

The VEGF polymorphisms studied are not implicated in susceptibility to IBD and do not predict sVEGF levels. Although increased sVEGF and angiogenesis are important features of IBD, they do not appear genetically determined.