Vascular endothelial growth factor gene polymorphisms contribute to the risk of endometriosis: an updated systematic review and meta-analysis of 14 case-control studies

Interferon Signaling in the Endometrium and in Endometriosis

Endometriosis is an estrogen-dependent inflammatory disease that develops in reproductive-aged women who experience pelvic pain and infertility. Even though endometriosis is not a new disease, its molecular etiology has not been clearly elucidated. Defects in the immune system might be one of the factors that promote endometriosis progression. For example, elevated levels of proinflammatory cytokines are associated with endometriosis. Interferon is one of the cytokines that is elevated in endometriotic tissues compared with normal endometrium. Therefore, high interferon levels play a crucial role in endometriosis progression. In addition to endometriosis, however, interferon has a critical role in endometrial function, particularly in the initiation and maintenance of pregnancy. Therefore, this review describes the double-edged sword of interferon signaling in normal endometrial function versus endometriosis progression and also discusses interferon targeting as a new nonhormonal therapy for endometriosis. This approach may increase the efficacy of endometriosis treatment and reduce the adverse effects associated with current hormonal therapy for this disease.

Genetic polymorphisms of Vascular Endothelial Growth Factor (VEGF) associated with endometriosis in Nigerian women

OBJECTIVE

To determine if genetic polymorphism of VEGF is associated with the development of endometriosis in Nigerian women.

STUDY DESIGN

Case control study of 100 women (50 healthy controls and 50 with endometriosis). Serum VEGF concentration of participants were determined using enzyme-linked immunosorbent assay (ELISA) technique. Genomic DNAs were isolated from peripheral blood samples and quantified by nanodrop spectrophotometer one. Single nucleotide polymorphisms genotyping was carried out by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP).

RESULTS

Mean age of participants was 32.96 ± 6.91 years for control and 32.04 ± 7.56 years for cases. VEGF levels in case and control groups were not statistically different (82.68 pg/ml [69.11-121.11 pg/ml] vs. 82.81 pg/ml [72.90-113.82 pg/ml] respectively; p = 0.967). All four genotypes examined were in Hardy-Weinberg equilibrium. Minor allele frequency of - 460T > C, - 1154G > A, + 936C > T and + 2578C > A were 24%, 8%, 6% and 10% in the control and 19%, 9%, 5% and 14% in endometriosis patients. However, allele and genotype distributions of - 460T > C, - 1154G > A, + 936C > T and + 2578C > A VEGF polymorphisms in endometriosis patients and control were not significantly different (p > 0.05).

CONCLUSION

Our preliminary findings revealed no association between endometriosis and - 460T > C, - 1154G > A, + 936C > T and + 2578C > A of VEGF genes among Nigerian women.

The Effect of Novel Medical Nonhormonal Treatments on the Angiogenesis of Endometriotic Lesions

Importance

Irrespective of the precise mechanisms leading to endometriosis, angiogenesis is essential for the establishment and long-term proliferation of the disease. As current surgical and medical management options for women with endometriosis have substantial drawbacks and limitations, novel agents are needed and molecules targeting the angiogenic cascade could serve as potential candidates.

Objective

Our aim was to review current data about the role of angiogenesis in the pathophysiology of endometriosis and summarize the novel antiangiogenic agents that could be potentially used in clinical management of patients with endometriosis.

Evidence Acquisition

Original research and review articles were retrieved through a computerized literature search.

Results

Loss of balance between angiogenic activators and suppressors triggers the nonphysiological angiogenesis observed in endometriotic lesions. Several proangiogenic mediators have been identified and most of them have demonstrated increased concentrations in the peritoneal fluid and/or serum of women with endometriosis. Among the antiangiogenic molecules, anti-vascular endothelial growth factor agents, dopamine agonists, romidepsin, and statins have shown the most promising results so far.

Conclusions and Relevance

Given the limitations of current treatments of endometriosis, there is a need for novel, more efficient agents. Antiangiogenic molecules could be used potentially in clinical management of women with endometriosis; however, their safety and efficiency should be carefully assessed prior to that. Further large prospective trials in humans are needed before any treatment is introduced into daily clinical practice.

Polymorphisms of vascular endothelial growth factor and recurrent implantation failure: a systematic review and meta-analysis

PURPOSE

To investigate the associations between polymorphisms of vascular endothelial growth factor (VEGF) with recurrent implantation failure (RIF).

METHODS

We performed the systematic review and meta-analysis by searching databases of PubMed, EMBASE, OVID, and CNKI (China National Knowledge Infrastructure) for studies that evaluated the associations between VEGF polymorphisms with RIF. Meta-analysis was performed if the polymorphism was studied by more than two case-control studies. Data were analyzed using R software. Odds ratios (ORs) with 95% confidence intervals (CIs) were reported to assess the associations.

RESULTS

Nine VEGF polymorphisms (-1154G > A, -460T > C, +405G > C, -7C > T, -634C > G, -2578C > A, +936C > T, 5C > T, -583C > T) were systematically reviewed. Meta-analysis was performed on VEGF -1154 G > A polymorphism. Three case-control studies consisted of 683 women were included in the quantitative meta-analysis (305 RIF patients and 378 controls). Results showed that VEGF -1154A allele was significantly associated with RIF (OR 1.39, 95% CI 1.08-1.78, P-value = 0.01). The dominant genetic model showed that VEGF 1154AA plus VEGF 1154AG genotypes were more frequent in RIF patients than VEGF 1154GG genotype (OR 1.56, 95% CI 1.10-2.20, P-value = 0.01). However, the result under the recessive genetic model showed no significant difference (OR 1.67, 95% CI 0.92-3.03, P-value = 0.09).

CONCLUSION

VEGF -1154A allele may serve as one of the predisposing factors of RIF. Women with VEGF 1154 AA/GA genotypes were at higher risk of RIF. However, we should consider the haplotype effect of VEGF polymorphisms in future studies.

Polymorphisms and endometriosis: a systematic review and meta-analyses

BACKGROUND

Endometriosis is an estrogen-dependent gynecological disorder that affects at least 10% of women of reproductive age. It may lead to infertility and non-specific symptoms such as chronic pelvic pain. Endometriosis screening and diagnosis are difficult and time-consuming. Late diagnosis (with a delay ranging from 3.3 to 10.7 years) is a major problem and may contribute to disease progression and a worse response to treatment once initiated. Efficient screening tests might reduce this diagnostic delay. As endometriosis is presumed to be a complex disease with several genetic and non-genetic pathogenic factors, many researchers have sought to identify polymorphisms that predispose to this condition.

OBJECTIVE AND RATIONALE

We performed a systematic review and meta-analysis of the most regularly reported polymorphisms in order to identify those that might predispose to endometriosis and might thus be of value in screening.

SEARCH METHODS

The MEDLINE database was searched for English-language publications on DNA polymorphisms in endometriosis, with no date restriction. The PubTator text mining tool was used to extract gene names from the selected publications' abstracts. We only selected polymorphisms reported by at least three studies, having applied strict inclusion and exclusion criteria to their control populations. No stratification based on ethnicity was performed. All steps were carried out according to PRISMA guidelines.

OUTCOMES

The initial selection of 395 publications cited 242 different genes. Sixty-two genes (corresponding to 265 different polymorphisms) were cited at least in three publications. After the application of our other selection criteria (an original case-control study of endometriosis, a reported association between endometriosis and at least one polymorphism, data on women of reproductive age and a diagnosis of endometriosis in the cases established by surgery and/or MRI and confirmed by histology), 28 polymorphisms were eligible for meta-analysis. Only five of the 28 polymorphisms were found to be significantly associated with endometriosis: interferon gamma (IFNG) (CA) repeat, glutathione S-transferase mu 1 (GSTM1) null genotype, glutathione S-transferase pi 1 (GSTP1) rs1695 and wingless-type MMTV integration site family member 4 (WNT4) rs16826658 and rs2235529. Six others showed a significant trend towards an association: progesterone receptor (PGR) PROGINS, interCellular adhesion molecule 1 (ICAM1) rs1799969, aryl-hydrocarbon receptor repressor (AHRR) rs2292596, cytochrome family 17 subfamily A polypeptide 1 (CYP17A1) rs743572, CYP2C19 rs4244285 and peroxisome proliferator-activated receptor gamma (PPARG) rs1801282), and 12 showed a significant trend towards the lack of an association: tumor necrosis factor (TNF) rs1799964, interleukin 6 (IL6) rs1800796, transforming growth factor beta 1 (TGFB1) rs1800469, estrogen receptor 1 (ESR1) rs2234693, PGR rs10895068, FSH receptor (FSHR) rs6166, ICAM1 rs5498, CYP1A1 rs4646903, CYP19A1 rs10046, tumor protein 53 (TP53) rs1042522, X-ray repair complementing defective repair in Chinese hamster cells 1 (XRCC1) rs25487 and serpin peptidase inhibitor clade E member 1 (SERPINE1) rs1799889; however, for the 18 polymorphisms identified in the latter two groups, further studies of the potential association with the endometriosis risk are needed. The remaining five of the 28 polymorphisms were not associated with endometriosis: glutathione S-transferase theta 1 (GSTT1) null genotype, vascular endothelial growth factor alpha (VEGFA) rs699947, rs833061, rs2010963 and rs3025039.

WIDER IMPLICATIONS

By carefully taking account of how the control populations were defined, we identified polymorphisms that might be candidates for use in endometriosis screening and polymorphisms not associated with endometriosis. This might constitute the first step towards identifying polymorphism combinations that predispose to endometriosis (IFNG (CA) repeat, GSTM1 null genotype, GSTP1 rs1695, WNT4 rs16826658 and WNT4 rs2235529) in a large cohort of patients with well-defined inclusion criteria. In turn, these results might improve the diagnosis of endometriosis in primary care. Lastly, our present findings may enable a better understanding of endometriosis and improve the management of patients with this disease.

The impact of vascular endothelial growth factor single nucleotide polymorphisms in the development and severity of endometriosis: A systematic review of the literature

OBJECTIVE

To review the impact of single nucleotide polymorphisms (SNPs) of the vascular endothelial growth factor (VEGF) gene in the development and severity of endometriosis.

SEARCH STRATEGY

We searched Medline, Scopus, Clinicaltrials.gov, EMBASE, Cochrane Central Register of Controlled Trials CENTRAL and Google Scholar databases for published studies in the field.

SELECTION CRITERIA

We included prospective and retrospective observational studies.

DATA COLLECTION AND ANALYSIS

Data extraction was performed using a modified data form that was based in Cochrane`s data collection form for intervention reviews.

MAIN RESULTS

Twenty studies were included that investigated the frequency of the various alleles of the -460C/T, +405G/C, +936C/T, -2578A/C and -1154G/A SNPs. The Hardy-Weinberg equilibrium revealed that the different genotypes were comparable among patients with endometriosis and control women, as well as among patients with mild and severe forms of the disease. No differences were observed in the expression of the various alleles in the majority of cases. Ethnical variations were observed; however, the results should be regarded as inconclusive due to the small amount of available data.

CONCLUSIONS

The results of our meta-analysis suggest that the investigated single nucleotide polymorphisms are unlikely to significantly contribute to the development and severity of endometriosis.

Evaluation of apoptosis and angiogenesis in ectopic and eutopic stromal cells of patients with endometriosis compared to non-endometriotic controls

Background

Endometriosis is a chronic, painful, and inflammatory disease characterized by extra-uterine growth of endometrial tissues. Increased angiogenesis and resistance to apoptosis have been suggested to be involved in pathogenesis and development of endometriosis. The objective of this study was to examine apoptosis potential and angiogenesis contribution of eutopic (EuESCs) and ectopic (EESCs) endometrial stromal cells in patients with endometriosis compared to endometrial stromal cells from non-endometriotic controls (CESCs).

Methods

Stromal cells were isolated by enzymatic digestion of ectopic (n = 11) and eutopic (n = 17) endometrial tissues from laparoscopically-confirmed endometriotic patients. Endometrial stromal cells of 15 non-endometriotic patients served as control. Following cell characterization by immunofluorescent staining and flow cytometry using a panel of antibodies, the total RNA was isolated from the cultured cells, and analyzed for the expression of genes involved in apoptosis (Bcl-2, Bcl-xL, Bax, and caspase-3) and angiogenesis [vascular endothelial growth factor-A (VEGF-A) and hepatocyte growth factor (HGF)] by Real-time PCR.

Results

Significantly higher gene expression levels of Bcl-2 and Bcl-xL were found in EESCs compared with EuESCs and CESCs (p < 0.01). The gene expression of Bax in EESCs, EuESCs, and CESCs was not statistically significant. Furthermore, EuESCs exhibited a significantly lower caspase-3 gene expression compared with CESCs (p < 0.01) or EESCs (p < 0.05). Regarding angiogenesis, VEGF-A gene expression in EESCs (p < 0.001) and EuESCs (p < 0.05) were significantly higher compared with those of CESCs. EESCs exhibited a significantly higher HGF gene expression compared with EuESCs (p < 0.05).

Conclusions

These findings suggest reduced propensity to apoptosis and increased angiogenesis potential of EESCs, which may be involved in pathogenesis of endometriosis.

EPHA3 enhances macrophage autophagy and apoptosis by disrupting the mTOR signaling pathway in mice with endometriosis

Background: Endometriosis is a chronic fibrotic disease characterized by agonizing pelvic pain and low fertility, mainly affecting middle-aged women. The aim of the present study is to assess the potential effects of erythropoietin-producing hepatocellular carcinoma A3 (EPHA3) on endometriosis, with emphasis on the autophagy and apoptosis of macrophages via inhibition of the mammalian target of rapamycin (mTOR) signaling pathway.

Methods: The mouse models of endometriosis were established followed by culturing the macrophages and macrophage transfection via the EPHA3 vector, siRNA EPHA3, and RAPA (an inhibitor of the mTOR signaling pathway). The expression of EPHA3, related factors in the mTOR signaling pathway, macrophage autophagy (autophagy-related gene 3 (Atg3), light chain 3-I (LC3-I), light chain 3-II (LC3-II) and Beclin1) and apoptosis (B-cell lymphoma-2 (bcl-2), bax and fas) were all detected and documented, respectively. The changes of autophagic lysosomes and the apoptosis of macrophages in each group following transfection were also inspected and detected.

Results: The results of the in silico analysis ascertained EPHA3 to be a candidate gene of endometriosis. After successful modeling, the uterine tissues of endometriosis mice presented with a low expression of EPHA3 and activated mTOR signaling pathway. Overexpression of EPHA3 inhibited the activation of the mTOR signaling pathway, down-regulated bcl-2 expression, up-regulated the expression of Atg3, LC3-II/LC3-I, Beclin1, bax and fas, and also promoted the autophagy and apoptosis of macrophages in endometriosis mice.

Conclusion: Altogether, EPHA3 could potentially promote the autophagy and apoptosis of macrophages in endometriosis via inhibition of the mTOR signaling pathway, highlighting the potential of EPHA3 as the target to treat endometriosis.

Defining the genetic profile of endometriosis

Endometriosis is a pathological condition which has been extensively studied, since its pathophysiology stems from a broad spectrum of environmental influences and genetic factors. Familial studies aim at defining inheritance trends, while linkage analysis studies focus on the identification of genetic sites related to endometriosis susceptibility. Genetic association studies take into account candidate genes and single nucleotide polymorphisms, and hence target at unraveling the association between disease severity and genetic variation. The common goal of various types of studies is, through genetic mapping methods, the timely identification of therapeutic strategies for disease symptoms, including pelvic pain and infertility, as well as efficient counselling. While genome-wide association studies (GWAS) play a primary role in depicting genetic contributions to disease development, they entail a certain bias as regards the case-control nature of their design and the reproducibility of the results. Nevertheless, genetic-oriented studies and the implementation of the results through clinical tests, hold a considerable advantage in proper disease management. In this review article, we present information about gene-gene and gene-environment interactions involved in endometriosis and discuss the effectiveness of GWAS in identitying novel potential therapeutic targets in an attempt to develop novel therapeutic strategies for a better management and treatment of patients with endometriosis.

Basic mechanisms of vascularization in endometriosis and their clinical implications

BACKGROUND

Vascularization is a major hallmark in the pathogenesis of endometriosis. An increasing number of studies suggests that multiple mechanisms contribute to the vascularization of endometriotic lesions, including angiogenesis, vasculogenesis and inosculation.

OBJECTIVE AND RATIONALE

In this review, we provide an overview of the basic mechanisms of vascularization in endometriosis and give special emphasis on their future clinical implications in the diagnosis and therapy of the disease.

SEARCH METHODS

Literature searches were performed in PubMed for English articles with the key words 'endometriosis', 'endometriotic lesions', 'angiogenesis', 'vascularization', 'vasculogenesis', 'endothelial progenitor cells' and 'inosculation'. The searches included both animal and human studies. No restriction was set for the publication date.

OUTCOMES

The engraftment of endometriotic lesions is typically associated with angiogenesis, i.e. the formation of new blood vessels from pre-existing ones. This angiogenic process underlies the complex regulation by angiogenic growth factors and hormones, which activate intracellular pathways and associated signaling molecules. In addition, circulating endothelial progenitor cells (EPCs) are mobilized from the bone marrow and recruited into endometriotic lesions, where they are incorporated into the endothelium of newly developing microvessels, referred to as vasculogenesis. Finally, preformed microvessels in shed endometrial fragments inosculate with the surrounding host microvasculature, resulting in a rapid blood supply to the ectopic tissue. These vascularization modes offer different possibilities for the establishment of novel diagnostic and therapeutic approaches. Angiogenic growth factors and EPCs may serve as biomarkers for the diagnosis and classification of endometriosis. Blood vessel formation and mature microvessels in endometriotic lesions may be targeted by means of anti-angiogenic compounds and vascular-disrupting agents.

WIDER IMPLICATIONS

The establishment of vascularization-based approaches in the management of endometriosis still represents a major challenge. For diagnostic purposes, reliable angiogenic and vasculogenic biomarker panels exhibiting a high sensitivity and specificity must be identified. For therapeutic purposes, novel compounds selectively targeting the vascularization of endometriotic lesions without inducing severe side effects are required. Recent progress in the field of endometriosis research indicates that these goals may be achieved in the near future.

Association between vascular endothelial growth factor promoter polymorphisms and the risk of recurrent implantation failure

The objective of the present study was to investigate the association between recurrent implantation failure (RIF) and vascular endothelial growth factor (VEGF) gene polymorphisms that are associated with various female infertility disorders. A total of 116 women diagnosed with RIF and 218 control subjects were genotyped for the VEGF -2578C>A, -1154G>A, -634C>G and 936C>T polymorphisms using a polymerase chain reaction-restriction fragment length polymorphism assay. The VEGF -2578AA genotype was associated with an increased prevalence (≥4) of RIF [adjusted odds ratio (AOR)=2.77; 95% confidence interval (CI)=1.10-7.02; P=0.031], whereas the VEGF -634CG+GG genotype was associated with an increased incidence of total RIF (AOR=2.03; 95% CI=1.02-4.05; P=0.044) and ≥4 RIF (AOR=3.16; 95% CI=1.19-8.37; P=0.021). The results of the haplotype analysis indicated that -2578A/-1154A/-634G/936C (AOR=1.76; 95% CI=1.03-3.00; P=0.040 for total RIF and AOR=2.11; 95% CI=1.12-3.97; P=0.021 for ≥4 RIF) was associated with the occurrence of RIF. In addition, it was revealed that there was a significant difference in serum prolactin level associated with the VEGF -634C>G polymorphism (P=0.013). Therefore the findings of the present study indicate that the VEGF -2578AA genotype, -634G allele and -2578A/-1154A/-634G/936C haplotype may be genetic markers for susceptibility to RIF. However, further studies on VEGF promoter polymorphisms that include an independent randomized-controlled population are required to confirm these results.

miRNA‑34a‑5p downregulation of VEGFA in endometrial stem cells contributes to the pathogenesis of endometriosis

Endometrial-derived stem cells (EnSCs) serve an important role in the development of endometriosis via retrograde menstruation. Abnormal expression of miRNAs in EnSCs is involved in the etiology of endometriosis, however, the mechanisms remain unclear. The aim of the present study was to investigate the expression of miR‑34a‑5p and VEGFA in endometrial samples from patients with or without endometriosis, and then examine the underlying mechanism of microRNA‑34a‑5p regulation of VEGFA in EnSCs. Endometrial samples from patients with or without endometriosis were collected, and miR‑34a‑5p expression in the two groups was measured using RT‑PCR. Human endometrial‑derived stem cells (hEnSCs) were isolated from these endometrial samples, and hEnSCs were transfected with the miR‑34a‑5p mimics or control miRNAs. qPCR and western blotting were performed to assess the effects of miR‑34a‑5p on the expression of VEGFA in hEnSCs, and cell growth was assessed by an MTT assay. miR‑34a‑5p was significantly downregulated in patients with endometriosis when compared with that of those without endometriosis. VEGFA expression levels in hEnSCs with an overexpression of miR‑34a‑5p were significantly reduced when compared with those in the negative control (P<0.01). In addition, the upregulation of miR‑34a‑5p suppressed EnSCs proliferation by targeting the 3' untranslated region of VEGFA. miR‑34a‑5p provides a novel avenue for the understanding of the development of endometriosis, and may facilitate the development of potential therapeutics against endometriosis.

PSYCHO-SOCIAL ASPECTS OF QUALITY OF LIFE IN WOMEN WITH ENDOMETRIOSIS

OBJECTIVES

The objective of this study was to assess the impact of endometriosis on the quality of life.

PATIENTS AND METHODS

Study group of 205 women, aged between 18-45 years old, hospitalized in the "Cuza-Voda" Hospital of Iasi, between 2013-2015. We used the Fertility Problem Inventory, the Endometriosis Health Profile and the Beck Depression Inventory.

RESULTS

We first realized a descriptive analyses of patients' health related quality of life - 60% of women reported higher infertility distress associated with relationship issues caused by difficulties to conceive. The descriptive analysis over the quality of life in patients with endometriosis suggests that the high level of stress related factors, are: the loss over the control of the symptoms, dyspareunia and altered emotional status. Regarding the sexual aspect of life, almost a quarter of the women complained about an altered sexual status, due to both fear of failing in conceiving and dyspareunia caused by the endometriosis. The descriptive analysis over the infertility related stress suggests that the factors associated with a high level of stress are: sadness, pessimism, feeling of failure, irritability, lack of confidence, self-hatred and fatigue.

CONCLUSIONS

Patients with endometriosis are dealing daily with a large spectrum of symptoms, including pain, dyspareunia, emotional instability and high levels of stress, which have a negative impact upon the quality of life, by lowering it on different levels. Also, within the present study we showed a significant presence of high infertility stress in patients of all ages that lead to depression and social anxiety.

Macrophage and nerve interaction in endometriosis

Dysregulation of the immune system in endometriotic milieus has been considered to play a pivotal role in the pathogenesis of endometriosis. Macrophage recruitment and nerve fiber infiltration are the two major characteristics of this aberrant immune environment. First, the recruitment of macrophages and their polarization phenotype within the endometriotic lesion have been demonstrated to facilitate the development and maintenance of endometriosis. M1 phenotype of macrophages has the capacity to secrete multiple cytokines for inflammatory response, while M2 macrophage possesses an opposite property that can mediate the process of immunosuppression and neuroangiogenesis. Upon secretion of multiple abnormal signal molecules by the endometriotic lesion, macrophages could alter their location and phenotype. These changes facilitate the accommodation of the aberrant microenvironment and the exacerbation of disease progression. Second, the infiltration of nerve fibers and their abnormal distribution are proved to be involved in the generation of endometriosis-associated pain and inflammatory response. An imbalance in sensory and sympathetic innervation and the abnormal secretion of different cytokines could mediate neurogenesis and subsequent peripheral neuroinflammation in endometriosis. Although endometriosis creates an inflammatory milieu promoting macrophage infiltration and an imbalanced innervation, interaction between macrophages and nerve fibers in this process remains unknown. The aim of this review is to highlight the role of macrophage and nerve interaction in endometriosis, where macrophage recruitment and neurogenesis can be the underlying mechanism of neuroinflammation and pathogenesis of endometriosis.

Allele rs2010963 C of the VEGFA gene is associated with the decreased risk of primary varicose veins in ethnic Russians

Objective To study the association of polymorphisms rs699947, rs2010963, rs3025039 in the VEGFA gene region and rs1870377, rs2305949, rs2071559 in the VEGFR2 gene region with the risk of primary varicose veins in ethnic Russians. Methods Genotypes were determined by real-time PCR allelic discrimination. The case group consisted of 448 patients with primary varicose veins and the control group comprised 609 individuals without a history of chronic venous disease. Association was studied by logistic regression analysis. Results Allele rs2010963 C was associated with the decreased risk of varicose veins (additive model of inheritance: odds ratio = 0.73, 95% confidence interval = 0.59-0.91, P = 0.004). Conclusions Our results provide evidence that polymorphism rs2010963 located in the 5' untranslated region of the VEGFA gene can influence genetic susceptibility to primary varicose veins in Russians. Otherwise, it can be in linkage disequilibrium with another functional single nucleotide polymorphism that can alter the level of vascular endothelial growth factor A protein.

Polymorphisms in VEGF and KDR genes in the development of endometriosis: a systematic review

Abstract Objectives: to review studies that used case-control design to verify the association of polymorphisms in VEGF and KDR genes in the development of endometriosis. Methods: the systematic review selected articles published until September 1, 2015 from PubMed, MEDLINE, BVS, SciELO databases, considering the following key words: endometriosis and ("polymorphism" or "SNP" or "genetic polymorphism") and ("VEGF" OR "Vascular endothelial growth factor" or "VEGFR-2" or "Vascular endothelial growth factor-2" or "KDR" or "Kinase Insert Domain Receptor"). Results: 106 articles were identified, only 11 were eligible. Discrepant results were observed regarding polymorphisms in VEGF gene in the development of endometriosis, which can be explained by methodological differences, sample size, eligible control type, using the unadjusted risk estimates and the heterogeneity of the studied population. Only one study investigated polymorphisms in KDR gene in the development of endometriosis, however it was ineligible for this review. Conclusions: to avoid discrepancy in the results, we suggest that the ideal control group should be formed by fertile women and free of gynecological diseases. Multicentric studies with adequate design, involving different population besides the combined analysis on polymorphisms in VEGF and KDR genes are still necessary to contribute in the understanding of this disease, which are social, clinical and economical problems.

Vascular endothelial growth factor pathway in endometriosis: genetic variants and plasma biomarkers

OBJECTIVE

To study single nucleotide polymorphisms (SNPs) involved in angiogenesis (VEGF, PLGF, VEGFR1, VEGFR2, HIF-1α) and plasma levels of the corresponding proteins (VEGF, PLGF, sVEGFR1, sVEGFR2) in women with and without endometriosis.

DESIGN

Allele frequencies of vascular endothelial growth factor (VEGF) pathway SNPs and plasma levels of the corresponding proteins were investigated in patients with endometriosis and in controls.

SETTING

University hospital.

PATIENT(S)

Samples of DNA from 1,931 Caucasian patients were included (1,109 patients with endometriosis and 822 controls). An additional study group included 973 DNA samples from volunteers, self-reported to be healthy without laparoscopic evaluation.

INTERVENTION(S)

Women who underwent a laparoscopy for subfertility and/or pain and healthy volunteers without laparoscopic evaluation.

MAIN OUTCOME MEASURE(S)

Functional SNPs of the VEGF, VEGFR1, VEGFR2, HIF-1α genes and Hap Map tagging SNPs of the PLGF gene were genotyped by using iPLEX technology on a Sequenom MassArray and TaqMan SNP Genotyping Assay. The VEGF levels were determined in ethylenediaminetetraacetic acid plasma samples by using Bio-Plex Protein Array System. PLGF, sVEGFR1, and sVEGFR2 levels were measured in ethylenediaminetetraacetic acid plasma samples by using ELISA Quantikine kits.

RESULT(S)

A significant association was found between the rs2268613 polymorphism in the PLGF gene and PLGF plasma levels. In all study subjects, women with the AA variant of the rs2268613 PLGF gene had significantly lower PLGF plasma levels (median [interquartile range] 9.36 [8.19-10.43] pg/mL) than those with the AG variant (12.1 [11.81-20.84] pg/mL; P(a)=.0085, P(b)=.04), both before and after multiple testing. Plasma levels of VEGF were elevated in endometriosis patients (especially in minimal-mild endometriosis during the menstrual cycle phase) compared with laparoscopic controls but had a moderate diagnostic performance (area under the curve, 0.73) in this discovery dataset. At a cut-off plasma level of VEGF >3.88 pg/mL, minimal-mild stages of endometriosis were diagnosed with a sensitivity of 74% and a specificity of 80% during the menstrual phase of cycle. The associations between the presence of endometriosis and SNPs in PLGF (rs2268614), HIF-1α (rs11549465), and VEGFR1 (rs9582036) genes lost statistical significance after multiple testing.

CONCLUSION(S)

Genetic variants in the PLGF rs2268613 gene may influence plasma levels of the corresponding protein. Plasma levels of VEGF were elevated in endometriosis patients compared with controls. The associations between the presence of endometriosis and SNPs in PLGF (rs2268614), HIF-1α (rs11549465), and VEGFR1 (rs9582036) genes lost statistical significance after multiple testing.

VASCULAR ENDOTHELIAL GROWTH FACTOR SERUM LEVELS IN WOMEN WITH ADVANCED ENDOMETRIOSIS

CONTEXT

Endometriosis is a common gynecological disease, characterized by ectopic deposits of endometrial tissue outside of the uterine cavity, and it is associated with pelvic pain and infertility, with an important impact on the quality of life. At this point there is a controversy regarding the etiology and pathophysiology of endometriosis and it seems that pro-angiogenic growth factors might be involved, but their role is not completely understood.

OBJECTIVE

To evaluate the serum concentration of the main growth factors in patients with diagnosed endometriosis compared to healthy controls.

SUBJECTS AND METHODS

A total of 157 women were divided into two study groups (Group I - endometriosis; Group 2 - healthy women). Serum levels of VEGF, G-CSF, GM-CSF, b-FGF, EGF, and HGF were measured with Human Multiplex Cytokine Panels.

RESULTS

VEGF serum levels were significantly lower in women with endometriosis compared to controls (1.924±0.145 compared to 1.806±0.078 pg/mL, p<0.001). Serum levels of GM-CSF, b-FGF, EGF, and HGF respectively did not differ significantly between patients with endometriosis and healthy controls. G-CSF had a very low detection rate.

CONCLUSIONS

The present study showed that VEGF serum levels are significantly lower in endometriosis patients compared to healthy controls, indicating a possible role in endometriosis pathogenesis.

Genetics of endometriosis

Endometriosis is a heritable complex disorder that is influenced by multiple genetic and environmental factors. Identification of these genetic factors will aid a better understanding of the underlying biology of the disease. In this article, we describe different methods of studying genetic variation of endometriosis, summarize results from genetic studies performed to date and provide recommendations for future studies to uncover additional factors contributing to the heritable component of endometriosis.

Profiling of Selected MicroRNAs in Proliferative Eutopic Endometrium of Women with Ovarian Endometriosis

It has been well documented that aberrant expression of selected microRNAs (miRNAs) might contribute to the pathogenesis of disease. The aim of the present study is to compare miRNA expression by the most comprehensive locked-nucleic acid (LNA) miRNA microarray in eutopic endometrium of patients with endometriosis and control. In the study we recruited 21 patients with endometriosis and 25 were disease-free women. The miRNA expression profiles were determined using the LNA miRNA microarray and validated for selected molecules by real-time PCR. We identified 1198 human miRNAs significantly differentially altered in endometriosis versus control samples using false discovery rate of <5%. However only 136 miRNAs showed differential regulation by fold change of at least 1.3. By the use of selected statistical analysis we obtained 45 potential pathways that might play a role in the pathogenesis of endometriosis. We also found that natural killer cell mediated cytotoxicity pathway was found to be inhibited which is consistent with previous studies. There are several pathways that may be potentially dysregulated, due to abnormal miRNA expression, in eutopic endometrium of patients with endometriosis and in this way contribute to its pathogenesis.

Vascular endothelial growth factor (-460 C/T, +405 G/C, and +936 C/T) polymorphisms and endometriosis risk in Tunisian population

The vascular endothelial growth factor (VEGF), a major angiogenic factor, is known to play an important role in the development of endometriosis. The aim of this study was to investigate the association of three VEGF (-460 C/T, +405 G/C, and +936 C/T) polymorphisms with the risk of endometriosis in the Tunisian population. This study includes 105 women with endometriosis and 150 women with no laparoscopic evidence of disease. Genotyping of the VEGF -460 C/T, +405 G/C, and +936 C/T polymorphisms were performed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). The distribution of genotypes (P = 0.006) and allele (P = 0.0009) frequencies of the +936 C/T polymorphism was significantly different between patients and controls. Patients with stages III-IV endometriosis showed a higher VEGF + 936T allele frequency than controls (P = 0.0001). However, the distribution of genotypes and allele frequencies of the VEGF -460 C/T and +405 G/C polymorphisms did not differ significantly between endometriosis patients and controls. These findings suggest that the VEGF +936 C/T polymorphism may be a risk factor for endometriosis development and the VEGF +936 T allele is associated with an increased risk of stages III-IV endometriosis in the Tunisian population.

The association between vascular endothelial growth factor (VEGF) +405G>C genetic polymorphism and endometriosis

The vascular endothelial growth factor (VEGF) is one of the most important candidate genes for the development of endometriosis, and VEGF genetic polymorphisms might be potentially associated with endometriosis risk. However, the results still remain controversial. The objective of this study aimed to perform a comprehensive meta-analysis to explore a better understanding of the effects of VEGF +405G>C genetic polymorphism on the risk of endometriosis. A total of eleven eligible studies were eventually identified in this meta-analysis, including 2829 endometriosis cases and 2947 controls. In the overall analysis, no significant association between the VEGF +405G>C genetic polymorphism and the risk of endometriosis was detected in all genetic models (for homozygote comparison [CC versus vs. GG]: OR = 1.21, 95% CI 0.67-2.19, P = 0.537; for heterozygote comparison [CG vs. GG]: OR = 1.16, 95% CI 0.86-1.56, P = 0.348; for dominant comparison CC/CG vs. GG: OR = 1.10, 95% CI 0.93-1.30, P = 0.263; for recessive comparison [CC vs. CG/GG]: OR = 1.03, 95% CI 0.73-1.47, P = 0.857; allele comparison [C vs. G]: OR = 0.99, 95% CI 0.70-1.40, P = 0.962). In the subgroup analysis by ethnicities, there was no significant association between VEGF +405G>C genetic polymorphism and endometriosis risk in Asians and/or Caucasians under all genetic models (all P-values >0.05). No publication bias was observed in this study. This meta-analysis supports that the VEGF +405G>C genetic polymorphism is not significant associated with the risk of endometriosis.

Involvement of vascular endothelial growth factor -460 C/T, +405 G/C and +936 C/T polymorphisms in the development of endometriosis

There are inconsistent data on the contribution of vascular endothelial growth factor (VEGF) -460 C/T (rs833061), +405 G/C (rs2010963) and +936 C/T (rs3025039) single-nucleotide polymorphisms (SNPs) to endometriosis in different ethnicities. Therefore, using high-resolution melting curve analysis, the present study examined the distribution of these SNPs in females with endometriosis-related infertility and a control group. None of the three VEGF SNPs were associated with endometriosis-related infertility in the dominant and recessive models. The lowest P-values of the trend were observed for the VEGF +936 C/T (rs3025039) SNP in endometriosis-related infertility (P_trend =0.149). Similarly, haplotype analyses of VEGF SNPs did not demonstrate any SNP combination as a risk for endometriosis-related infertility, and the lowest overall P-values, P=0.141 and P_corr =0.395, were observed for a haplotype (TGT) of the above SNPs. Taken together, these results did not demonstrate the contribution of VEGF C/T, +405 G/C and +936 C/T SNPs to endometriosis-related infertility.

Role of vascular endothelial growth factor polymorphisms (-2578C>A, -460 T>C, -1154G>A, +405G>C and +936C>T) in endometriosis: a case-control study with Brazilians

Background

Endometriosis is regarded as a complex and heterogeneous disease in which genetic and environmental factors contribute to the phenotype. The Vascular Endothelial Growth Factor (VEGF) plays important roles in the pathogenesis of endometriosis. The present study was aimed at investigating the contribution of VEGF polymorphisms as risk factors for the development of endometriosis. This is the first study to evaluate the combined influence of the five most common VEGF polymorphisms.

Methods

This study was conducted at two hospitals from the Brazilian public health system, and comprised 294 women submitted to laparoscopic or laparotomy surgery: 182 patients had a histologically confirmed diagnosis of endometriosis (cases), whereas 112 had no evidence of the disease (controls). The VEGF polymorphisms were determined by TaqMan real-time polymerase chain reaction. The odds ratio (OR) with their 95% confidence intervals (CI) were calculated using an unconditional logistic regression model.

Results

Endometriosis patients and controls did not differ regarding age distribution, whereas the body mass index was significantly lower in endometriosis patients, when compared with controls (23.1 ± 3.9 versus 27.3 ± 5.9, P < 0.001). The evaluation of gynecological symptoms, including dysmenorrhea, non-cyclic chronic pelvic pain, dyspareunia and infertility, indicates significantly higher prevalences among endometriosis cases. The variant allele -1154A was significantly associated with endometriosis, either considering all cases (OR: 1.90, 95% CI: 1.23–2.97), deep infiltrating endometriosis (DIE) (OR: 1.83, 95% CI: 1.16-2.90) or moderate and severe endometriosis (stages III-IV) (OR: 1.97, 95% CI: 1.21-3.19). No significant differences were found in allele or genotype distributions of the –2578C > A, -460 T > C, +405G > C and +936C > T polymorphisms between endometriosis cases and controls. A total of six haplotypes were inferred derived from four polymorphisms (-2578C > A, -460 T > C, -1154G > A and +405G > C). There was a protective association between CCGG haplotype and endometriosis, either considering all cases (OR: 0.36, 95% CI: 0.15–0.86), DIE (OR: 0.37 95% CI: 0.15 – 0.90) or stages III-IV (OR: 0.35 95% CI: 0.13 – 0.95).

Conclusions

The present results indicate a positive association between VEGF -1154G > A and the risk of developing endometriosis, whereas the CCGG haplotype may be protective against the development of disease.

Distinct peritoneal fluid ghrelin and leptin in infertile women with endometriosis and their correlation with interleukin-6 and vascular endothelial growth factor

OBJECTIVE

The objective of the present study was to evaluate the levels of leptin, ghrelin, interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) in peritoneal fluid in patients with endometriosis and infertility, and study their correlation.

DESIGN AND SETTING

This cross-sectional study included women undergoing diagnostic and/or therapeutic laparoscopy for endometriosis with chief complaint of infertility and/or pain at a tertiary care hospital. Based upon laparoscopic and histopathological findings, patients were categorized as with endometriosis and no endometriosis. Of the 50 patients with infertility (age 23-41 years), 19 had endometriosis while 31 had no endometriosis. The markers were assessed using ELISA kits.

RESULTS

The median levels of leptin in patients with endometriosis (10.20 ng/mL) were higher (p = 0.04) and median levels of ghrelin in patients with endometriosis (150.4 pg/mL) were lower (p = 0.037) versus patients with no endometriosis (5.07 ng/mL and 229.6 pg/mL, respectively). The median levels of IL-6 and VEGF in patients with endometriosis were not different between the groups. The correlation analyses showed that leptin levels and IL-6 were positively correlated (p = 0.0001).

CONCLUSIONS

The results suggest that ghrelin and leptin might play a key role in pathophysiology of endometriosis, and leptin is associated with inflammation in endometriosis.

Impact of surgical excision of lesions on pain in a rat model of endometriosis

BACKGROUND

Chronic pain is the most common and disabling feature of endometriosis. Surgical excision of endometriosis lesions provides relief but pain relapse is common. Studies in a preclinical model of endometriosis might help to unravel the role of the ectopic lesions as the source of pain. Thus, we evaluated the impact of lesion excision on mechanical hyperalgesia in a preclinical model of endometriosis pain.

METHODS

Endometriosis was induced by implanting autologous uterine tissue onto the gastrocnemius muscle. Surgical excision or aspiration drainage of the cystic lesion was performed at different times post-implant and mechanical nociceptive thresholds were assessed at the site of the lesion.

RESULTS

Lesions at 2, 8 and 16 weeks post-implant produced mechanical hyperalgesia of similar magnitude (n = 6/group). Excision of lesions (n = 6/group) produced a longer inhibition, with a magnitude and time course depending upon the timing of excision. Excision at 2 and 8 weeks produced a rapid onset marked attenuation of hyperalgesia, which returned to pre-excision values by post-surgical week 3. In contrast, excision of the lesion at 16 weeks produced a peak of inhibition of hyperalgesia 2 weeks post-excision, but then the inhibition was sustained. Aspiration of fluid from cysts in the lesions briefly attenuated mechanical hyperalgesia (n = 6/group).

CONCLUSIONS

In this preclinical model, we demonstrate that endometriosis pain is alleviated by surgical excision of the ectopic lesion or drainage of its cysts, providing support for the clinical observation that endometriosis pain is dependent upon the ongoing presence of the lesions.

Polymorphisms of VEGF and VEGF receptors are associated with the occurrence of ovarian hyperstimulation syndrome (OHSS)-a retrospective case-control study

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is the most serious complication of IVF/ICSI therapy. The pathophysiology and etiology of the disease is still not fully clarified.

METHODS

To assess whether polymorphisms of the VEGF/VEGF-receptor system contribute to the occurrence of ovarian hyperstimulation syndrome (OHSS), we performed a retrospective analysis of 116 OHSS patients, and 124 female controls. The following SNPs were genotyped: Rs2071559 (VEGFR2-604); rs2305948 (VEGFR2-1192); rs1870377 (VEGFR2-1719); rs2010963 (VEGF-405); and rs111458691 (VEGFR1-519). Odds ratios (ORs) were estimated with a 95% confidence interval (CI). Linkage disequilibrium (LD) analysis was performed in the three loci of the VEGFR2 gene.

RESULT

We found an overrepresentation of the T allele of the VEGFR1-519 polymorphism in OHSS patients (P = 0.02, OR: 3.62, CI: 1.16 - 11.27). By genotype modeling, we found that polymorphism of VEGFR1-519 and VEGF-405 showed significant differences in patients and controls (p = 0.02, OR: 3.79 CI: 1.98 - 11.97 and p = 0.000005, OR: 0.29, CI: 0.17 - 0.50). LD analysis revealed significant linkage disequilibrium in VEGFR2.

CONCLUSION

Polymorphisms in the VEGFR2 gene and in the VEGF gene are associated with the occurrence of OHSS. This strengthens the evidence for an important role of the VEGF/VEGF- receptor system in the occurrence of OHSS.

Association of the vascular endothelial growth factor (VEGF) gene single-nucleotide polymorphisms with osteosarcoma susceptibility in a Chinese population

Osteosarcoma (OS) is the most common bone malignancy worldwide. The vascular endothelial growth factor (VEGF) gene plays an important role in the pathogenesis of OS. The objective of this study aimed to detect the potential association between VEGF genetic polymorphisms and OS susceptibility in Chinese Han population. We recruited 330 OS patients and 342 cancer-free controls in this case-control study. Three single-nucleotide polymorphisms (SNPs) (-634 G > C, +936 C > T, and +1612 G > A) of the VEGF gene were investigated by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method and confirmed by direct DNA sequencing. Among these SNPs, we found that the genotypes/alleles of +936 C > T were statistically associated with the increased risk of OS (TT versus (vs.) CC: OR = 2.70, 95% CI 1.34-5.45, χ(2) = 8.2271, p = 0.0041; T vs. C: OR = 1.31, 95% CI 1.02-1.68, χ(2) = 4.3861, p = 0.0362). The T allele and TT genotype of +936 C > T could be factors that increase the risk for susceptibility to OS. The results from this study suggest that VEGF genetic variants are potentially related to OS susceptibility in Chinese Han population and might be used as molecular markers for assessing OS susceptibility.