Vascular endothelial growth factor (VEGF) is released from platelets during blood clotting: implications for measurement of circulating VEGF levels in clinical disease

Prognostic role of vascular endothelial growth factor in hepatocellular carcinoma: systematic review and meta-analysis

Hepatocellular carcinoma (HCC) is a highly vascular tumour that expresses vascular endothelial growth factor (VEGF). Various studies have evaluated the prognostic value of VEGF levels in HCC. Its overall test performance remains unclear, however. The aim was to perform a systematic review and meta-analysis of prognostic cohort studies evaluating the use of VEGF as a predictor of survival in patients with treated HCC. Eligible studies were identified through multiple search strategies. Studies were assessed for quality using the Newcastle–Ottawa Tool. Data were collected comparing disease-free and overall survival in patients with high VEGF levels as compared to those with low levels. Studies were pooled and summary hazard ratios were calculated. A total of 16 studies were included for meta-analysis (8 for tissue and 8 for serum). Methodological analysis indicated a trend for higher study quality with serum studies as compared to tissue-based investigations. Four distinct groups were pooled for analysis: tissue overall survival (n=251), tissue disease-free survival (n=413), serum overall survival (n=579), and serum disease-free survival (n=439). High tissue VEGF levels predicted poor overall (HR=2.15, 95% CI: 1.26–3.68) and disease-free (HR=1.69, 95% CI: 1.23–2.33) survival. Similarly, high serum VEGF levels predicted poor overall (HR=2.35, 95% CI: 1.80–3.07) and disease-free (HR=2.36, 95% CI 1.76–3.16) survival. A high degree of inter-study consistency was present in three of four groups analysed. Tissue and serum VEGF levels appear to have significant predictive ability for estimating overall survival in HCC and may be useful for defining prognosis in HCC.

VEGF serum levels in depressed patients during SSRI antidepressant treatment

Recent evidence indicates that the vascular endothelial growth factor (VEGF) may be involved in the neuronal mechanisms underlying both the depression aetiology and the response to pharmacological and non pharmacological antidepressant treatments. To investigate whether VEGF peripheral levels are altered in depression and are modulated by antidepressant therapies, we analyzed the serum VEGF concentrations in 25 subjects affected by major depression (MD) before (T0) and after 8 (T8) and 12 (T12) weeks of escitalopram treatment. No significant alterations in VEGF serum levels were found at T0, even considering possible effects of confounders such as gender and smoking habit (r2=0.227 p=0.74). No changes appeared during the treatment (F(1.83, 43.86)=0.962; p=0.383) and there was no correlation between percentage VEGF variations at T12 and symptoms improvements (p=0.823). The present work represents the first report on the evaluation of serum VEGF levels in MD patients. However, before discarding serum VEGF as a biochemical marker in the diagnosis and treatment of depression, our negative results need to be confirmed in larger patient samples stratified for clinical characteristics, co-morbidities, cardiovascular diseases and confounding factors.

Mechanisms of thrombogenesis in atrial fibrillation: Virchow's triad revisited

Atrial fibrillation is the most common sustained cardiac arrhythmia, which is associated with a high risk of stroke and thromboembolism. Increasing evidence suggests that the thrombogenic tendency in atrial fibrillation is related to several underlying pathophysiological mechanisms. Abnormal changes in flow are evident by stasis in the left atrium, and seen as spontaneous echocontrast. Abnormal changes in vessel walls-essentially, anatomical and structural defects-include progressive atrial dilatation, endocardial denudation, and oedematous or fibroelastic infiltration of the extracellular matrix. Additionally, abnormal changes in blood constituents are well described, and include haemostatic and platelet activation, as well as inflammation and growth factor changes. These changes result in the fulfilment of Virchow's triad for thrombogenesis, and accord with a prothrombotic or hypercoagulable state in this arrhythmia. In this Review, we present an overview of the established and purported mechanisms for thrombogenesis in atrial fibrillation.

Prognostic factors for patients with hepatocellular carcinoma with macroscopic portal vein or inferior vena cava tumor thrombi receiving external-beam radiation therapy

Prognostic factors in patients with hepatocellular carcinoma (HCC) with tumor thrombosis are not well established, especially for those given external-beam radiation therapy (EBRT). Patients (n = 136) with HCC who had portal vein (PV) or inferior vena cava (IVC) tumor thrombus received EBRT between January 1998 and October 2007. Demographic variables, laboratory values, tumor characteristics, and treatment modalities were determined at diagnosis and before EBRT. The total radiation dose ranged from 30 to 60 Gy (median, 50 Gy) and was focused on the tumor thrombi. Predictors of survival were identified using the univariate and multivariate analysis. Of the 136 patients, the tumor thrombus completely disappeared in 41 patients (30.1%), 36 patients (26.5%) had a partial response, 49 patients (36%) had stable disease, and 10 patients (7.4%) had progressive disease. On multivariate analysis, pretreatment unfavorable predictors were associated with lower albumin, higher gamma-glutamyltransferase and alpha-fetoprotein levels, poorer Child-Pugh classification, intrahepatic multifocality, lymph node metastases, poorer response to EBRT, and 2-dimension EBRT technique. Survival rates at 1, 2, and 3 years were 31.8%, 17.5%, and 8.8% for patients with PV tumor thrombi; 66.3%, 21.1%, and 15.8% for IVC tumor thrombi; and 25%, 8.3%, and 0% for PV plus IVC tumor thrombi, respectively. Overall median survival was 9.7 months. This study provides detailed information about the survival outcomes and prognostic factors of HCC with tumor thrombi in a relatively large cohort of patients treated with radiation, and the results will help in understanding the potential factors that influence survival for patients with HCC after EBRT.

Quantitative analysis of vascular endothelial growth factor in liver metastases from pancreatic carcinoma as a predictor of chemotherapeutic effect and prognosis

PURPOSE

In pancreatic carcinoma, vascular endothelial growth factor (VEGF) expression at the primary site has been suggested to be a prognostic parameter. We quantitatively analyzed VEGF expression in liver metastases from pancreatic carcinoma and examined the correlation among VEGF expression in liver metastases, clinicopathologic factors, and clinical outcome.

EXPERIMENTAL DESIGN

The subjects consisted of 23 patients with pancreatic adenocarcinoma who had liver metastases and were treated with S-1 and gemcitabine as the first-line treatment. VEGF expression was quantitated by enzyme immunoassay in biopsy specimens of liver metastases and nontumorous liver tissue, and in plasma. In 10 of the 23 patients, VEGF expression was also quantitated in biopsy specimens of the primary pancreatic tumor. All samples were collected before treatment.

RESULTS

The VEGF level in nontumorous liver tissue was 36.6 +/- 10.0 pg/mg protein versus 376.8 +/- 106.1 pg/mg protein in liver metastases (P = 0.0016). Pretreatment VEGF levels in plasma and in primary pancreatic carcinoma did not correlate with VEGF levels in the corresponding liver metastases. The median VEGF level in liver metastases (138.9 pg/mg protein) was used as the cutoff value between high and low VEGF expression in liver metastases. Patients showing high VEGF expression had a significantly longer progression-free survival and overall survival than patients showing low VEGF expression in liver metastases (P = 0.0219 and P = 0.0074, respectively).

CONCLUSIONS

Evaluation of VEGF levels in liver metastases might be useful in assessing the prognosis of patients with metastatic pancreatic carcinoma who are under systemic chemotherapy.

Circulating vascular endothelial growth factor and systemic inflammatory markers in patients with stable and exacerbated chronic obstructive pulmonary disease

The aim of the present study was to assess circulating levels of VEGF (vascular endothelial growth factor), a biomarker with prognostic significance in cardiovascular disease, and markers of systemic inflammation in patients with stable and exacerbated COPD (chronic obstructive pulmonary disease). Lung function parameters, arterial blood gas analysis and circulating levels of VEGF, IL-6 (interleukin-6), TNF-alpha (tumour necrosis factor-alpha), CRP (C-reactive protein), fibrinogen and the peripheral blood neutrophil cell count were assessed in 30 patients on admission to the hospital for acute exacerbation of COPD, in 30 age-, gender- and BMI (body mass index)-matched patients with stable COPD, and 30 matched controls with normal lung function. Patients with acute exacerbated COPD had higher circulating concentrations of VEGF (P<0.001), IL-6 (P<0.05) and CRP (P<0.01) and an increased blood neutrophil cell count (P<0.05) compared with patients with stable COPD and healthy controls. VEGF levels in exacerbated COPD correlated with systemic inflammatory markers, such as CRP (r=0.61, P<0.005), IL-6 (r=0.46; P<0.01) and fibrinogen (r=0.39, P<0.05). In patients with stable COPD, there was a significant relationship between circulating VEGF levels and the percentage of the predicted FEV(1) (forced expiratory volume in 1 s) (r=0.47, P<0.01). Recovery from the exacerbation resulted in a significant decrease in both circulating VEGF levels and markers of systemic inflammation. In conclusion, circulating levels of VEGF and markers of systemic inflammation are up-regulated in patients with acute exacerbated COPD and decrease after recovery from the exacerbation.

Prevalence, aetiologies and significance of clubbing in a department of general internal medicine

BACKGROUND

Clubbing remains an amazing clinical sign. Its strong association with serious disease is still a clinical enigma. Moreover, the significance of diagnosing clubbing is not well established. The aim of our study was to evaluate prevalence, aetiology and clinical significance of clubbing in a department of general internal medicine.

PATIENTS AND METHODS

During one year (1511 admissions), all patients with digital clubbing assessed by determining ratio of the distal phalangeal depth (DPD) to the interphalangeal depth (IPD) and with the presence of Swamroth sign were included. Fifteen patients were diagnosed with clubbing (10 males and 5 females). They underwent complete physical examination, pulmonary CT-scan, bone scintigraphy, blood gas analysis and were compared with 86 matched controls.

RESULTS

Aetiology were renal cell carcinoma, pulmonary arteriovenous malformation, AIDS, inflammatory pseudo-tumour of the lung, adenocarcinoma of unknown origin in one case and in one case, Pet-scan suspected neoplasia but histology was not obtained. In 9 cases, no aetiology was found. Bone scan was normal in 14 cases and revealed periostitis in one case (idiopathic clubbing). Compared to control group, there was no difference in blood gas analysis but emphysema was more often present in patients with clubbing (p<0.01). No patient without aetiology developed cancer in the one year follow-up.

CONCLUSION

Clubbing is present in 1% of admission in a department of general internal medicine and is associated in nearly 40% with serious disease. In 60% of cases, aetiology is not identified but follow-up do not disclosed cancer.

Vascular endothelial growth factor in severe sepsis and septic shock

BACKGROUND

Vascular endothelial growth factor (VEGF) levels have been shown to be elevated in severe sepsis. We investigated the value of VEGF in predicting organ dysfunction and hospital mortality in adult patients with severe sepsis.

METHODS

We conducted a prospective observational cohort study in 24 closed multidisciplinary intensive care units (ICU) in Finland. All ICU admission episodes (4500) were screened for severe sepsis from November 1, 2004, to February 28, 2005. Patients were eligible if they fulfilled the criteria for severe sepsis.

RESULTS

Severe sepsis was found in 470 patients. Laboratory samples were obtained after informed consent from 250 patients at study entry (day 0) and from 215 patients after 72 h. These samples were compared with samples from 30 healthy individuals. The ICU mortality was 13.2% and hospital mortality 26%. Median serum VEGF concentrations on day 0 were 423 pg/mL (interquartile range [IQR] 159 and 858 pg/mL), and after 72 h were 521 pg/mL (IQR 182 and 1092 pg/mL), which were both higher than in healthy controls (P = 0.029 and 0.003, respectively). Low VEGF concentrations were associated with more severe renal and hematological dysfunction (Sequential Organ Failure Assessment scores 3-4 compared with scores 0-2). VEGF concentrations in day 0 and after 72 h were lower in nonsurvivors (P = 0.01 and <0.01, respectively) than in survivors, but the receiver operating characteristic curve analyses of concentrations of VEGF on day 0 and at 72 h revealed areas under the curve of 0.58 and 0.63 (95% confidence limits 0.48-0.68 and 0.54-0.72, P = 0.1 and 0.009, respectively).

CONCLUSIONS

VEGF concentrations are increased in patients with severe sepsis. Low concentrations are associated with hematological and renal dysfunction. VEGF concentrations were lower in nonsurvivors than in survivors, but did not adequately predict hospital mortality in patients with severe sepsis.

Plasma levels of vascular endothelial growth factor after treatment for cerebral arteriovenous malformations

BACKGROUND AND PURPOSE

The role of abnormal angiogenesis in the formation and progression of cerebral arteriovenous malformations (AVMs) is unclear. Previous studies have demonstrated increased local expression of vascular endothelial growth factor (VEGF) in AVM tissue and increased circulating levels of VEGF in AVM patients. We sought to further investigate the role of VEGF in AVM pathophysiology by examining changes in plasma VEGF levels in patients undergoing treatment for AVMs.

METHODS

Three serial blood samples were obtained from 13 AVM patients undergoing treatment: (1) before any treatment, (2) 24 hours postresection, and (3) 30 days postresection. Plasma VEGF concentrations were measured via commercially available enzyme-linked immunosorbent assay (ELISA). For controls, blood samples were obtained from 29 lumbar laminectomy patients.

RESULTS

The mean plasma VEGF level in AVM patients at baseline was 36.08+/-13.02 pg/mL, significantly lower than that of the control group (80.52+/-14.02 pg/mL, P=0.028). Twenty-four hours postresection, plasma VEGF levels dropped to 20.09+/-4.54 pg/mL, then increased to 66.81+/-26.45 pg/mL 30 days later (P=0.048). The mean plasma VEGF concentration 30 days after resection was no longer significantly different from the control group (P=0.33).

CONCLUSIONS

Plasma VEGF levels in 13 AVM patients were unexpectedly lower than controls, dropped early after AVM resection, then significantly increased 30 days later. These results support the key role of abnormal angiogenesis in AVM pathophysiology and suggest that a disruption in systemic VEGF expression may contribute to the natural history of these lesions.

Optimisation of circulating biomarkers of cell death for routine clinical use

BACKGROUND

M30 and M65 enzyme-linked immunosorbent assays detect circulating cytokeratin 18 fragments released during caspase-dependent or total cell death, respectively, and have potential as biomarkers in epithelial cancers. While these assays have been validated, their robustness for routine clinical use is unknown.

PATIENTS AND METHODS

M30 and M65 were measured in matched serum and plasma samples from 31 lung cancer patients and 18 controls.

RESULTS

Time allowable between sample acquisition and processing is critical for assays in clinical use. A 4-h delay in processing at room temperature increased M30 (P < 0.0001), an effect minimised by incubation on ice. M30 and M65 in serum were resistant to processing variations including delays. Serum and plasma measurements correlated well although M30 but not M65 was lower in serum (P < 0.0005). Less variation between duplicate assays was observed in serum. Prolonged storage (-80 degrees C) led to increased M30 (12%, 6 months; 34%, 1 year). Sample dilution in the supplied assay diluent proved non-linear, whereas dilution in donor serum or porcine plasma restored linearity up to a ratio of 1 : 6.

CONCLUSION

We present recommendations that improve the reliability of these assays for clinical use and recommend serum as the preferred matrix with data more resistant to variations in collection.

Normal human primary CD4+ T lymphocytes synthesize and release functional osteoprotegerin in vitro

Osteoprotegerin (OPG) acts as a decoy receptor for receptor activator of nuclear factor-kappaB ligand (RANKL) and TNF-related apoptosis-inducing ligand (TRAIL). OPG regulates bone remodeling and the immune response. The primary objective was to decipher, among human peripheral blood mononuclear leukocytes (PBML) that produce OPG, the subset(s) responsible for this synthesis and its regulation. To this end, normal human PBML and CD4-, 8-, 19-, 14-enriched subpopulations were studied in vitro for OPG synthesis. PBML were subjected to adherence and immunomagnetic separation, and OPG expression was analyzed by PCR, northern and western blotting, and ELISA. The antiapoptotic effects of OPG were studied on TRAIL-stimulated RPMI 8226 myeloma cells. OPG was time-dependently produced by primary CD4+ T lymphocytes exclusively. OPG secretion was upregulated by anti-CD3 antibody stimulation or incubation with interleukin (IL)-4, IL-1beta, TNF-alpha, GM-CSF, and vitamin D(3). In contrast, IL-10 inhibited the basal and IL-4-induced production of OPG by T cells. Conditioned media from activated T lymphocytes decreased TRAIL-induced apoptosis of RPMI 8226 cells. This effect was reversed by addition of RANKL to the T-cell conditioned media. As human immunodeficiency virus-1 (HIV-1) targets CD4+ T cells, we evaluated the effects of recombinant HIV-1 gp120 proteins on OPG synthesis. The gp120 from three different HIV-1 strains significantly reduced the basal output of OPG from T cells. Furthermore, all four protease inhibitors (PIs) used in highly active antiretroviral therapy decreased OPG synthesis by human blood T cells, nelfinavir being the most efficient PI. The simultaneous presence of an HIV-1 gp120 and a PI abrogated the basal output of OPG. In conclusion, these results highlight a new role for T lymphocytes involved in pathologies. Activated CD4+ T cells could, through OPG release, have a paracrine effect on adjacent cells and contribute to reduce the local process of bone remodeling and cellular apoptosis.

Thrombospondins use the VLDL receptor and a nonapoptotic pathway to inhibit cell division in microvascular endothelial cells

TSPs 1 and 2 function as endogenous inhibitors of angiogenesis. Although thrombospondins (TSPs) have been shown to induce apoptosis in HMVECs, we reasoned that a homeostatic mechanism would also be needed to inhibit EC growth without causing cell death, e.g., in the maintenance of a normal vascular endothelium. HMVECs, cultured in low serum, responded to VEGF with an increase in [(3)H]thymidine incorporation that was inhibited by TSPs and was accompanied by decreases in the phosphorylation of Akt and MAPK, without an increase in apoptosis. RAP, an inhibitor of the low-density lipoprotein (LDL) family of endocytic receptors, and blocking antibodies to VLDLR were as effective as TSPs in the inhibition of thymidine uptake in response to VEGF, and the effects of these agents were not additive. Supportive evidence for the role of the VLDLR in mediating this inhibition was provided by the demonstration of a high-affinity interaction between TSPs and the VLDLR. We propose that TSP1 and TSP2, together with the VLDLR, initiate a nonapoptotic pathway for maintenance of the normal adult vascular endothelium in a quiescent state, similar to that invoked for the regulation of mitogenesis by PDGF, but involving signaling via the VLDLR rather than LRP1.

The role of vascular endothelial growth factor leading to vascular leakage in children with dengue virus infection

Increased vascular permeability is the main aetiology for hypovolaemic shock and circulatory failure in dengue haemorrhagic fever (DHF).

AIM

To investigate the role of vascular endothelial growth factor (VEGF) in the pathogenesis of DHF.

METHODS

Serum samples from 41 patients [15 dengue fever (DF), 26 DHF] with serologically confirmed dengue virus infection during the febrile, toxic, convalescent stages and at follow-up were analysed for VEGF. Plasma samples from an additional 27 children (16 DF and 11 DHF) during the febrile, toxic stages and at 4-week follow-up and from eight healthy controls were analysed for VEGF.

RESULTS

Serum and plasma VEGF levels were not elevated during the febrile or toxic stages of dengue virus infection and did not differ between patients with DF and DHF.

CONCLUSION

Plasma leakage in patients with DHF cannot be explained by elevation of VEGF during the toxic stage of the illness.

Platelet-associated PF-4 as a biomarker of early tumor growth

Early tumor detection and intervention are important determinants of survival in patients with cancer. We have recently reported that the "platelet angiogenesis proteome" may be used to detect microscopic tumors in mice. We now present evidence that changes in platelet-associated platelet factor-4 (PF-4) detect malignant growth across a spectrum of human cancers in mice. A deregulated expression of an 8206-Da protein was observed by surfaceenhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-ToF MS) proteomic comparison of platelets from normal and tumor-bearing mice. The differentially expressed protein was identified as PF-4 by tandem mass spectrometry and ProteinChip immunoassay using anti-PF-4 antibody. The platelet-associated PF-4 appeared to be up-regulated in early growth of human liposarcoma, mammary adenocarcinoma, and osteosarcoma. A 120-day follow-up study of liposarcoma revealed a sustained 2-fold or higher increase of platelet-associated PF-4 at 19, 30, and 120 days. In contrast, only an insignificant change of PF-4 was observed in the plasma of mice bearing the different human tumor xenografts, and throughout the 120 days of the liposarcoma study. We conclude that platelet-associated PF-4, but not its plasma counterpart, may represent a potential biomarker of early tumor presence.

Pathophysiological mechanisms of angiogenesis

The growth of new blood vessels may be either beneficial or harmful. The angiogenic process may be measured by a variety of techniques, although it may often be the quality rather than quantity of resulting blood vessels that determines function. Endothelial cells play a key role in the initiation of angiogenesis, and vascular endothelial growth factor (VEGF) may be viewed as a prototypical direct-acting angiogenic factor. VEGF acts through multiple cell surface receptors and signaling pathways to stimulate endothelial cell proliferation, survival, and migration. By inducing other growth factor expression, VEGF stimulates a cascade of angiogenic activity. Different tissues may utilize various angiogenic pathways that are modulated by diverse host tissue responses. Furthermore, a single tissue may progress through a sequence of angiogenic pathways, for example, as acute injury progresses to chronic inflammation. The phenotype of the resulting neovasculature is critically dependent on the context in which it is formed. Biomarkers of angiogenesis are being developed as an aid to assessing human disease. Histological assessment of vascular density and angiogenic factor expression, in vivo imaging, Doppler ultrasound, and biofluid assays each may have clinical utility. Therapeutic targeting of angiogenesis will depend both on the generation of acceptable pharmacological agents and on the identification of patients who may and do gain benefit from such treatments.

Evaluation of a xenogeneic VEGF vaccine in dogs with soft tissue sarcoma

Active immunization against pro-angiogenic growth factors or their receptors is an emerging strategy for controlling tumor growth and angiogenesis. Previous studies in rodent tumor models have indicated that immunization against xenogeneic growth factors is more likely to induce effective anti-tumor responses than immunization against the autologous growth factor. However, the effectiveness or safety of the xenogeneic vaccination approach has not been previously assessed in a clinically relevant outbred, spontaneous tumor model. Therefore, we investigated the safety and anti-tumor and anti-angiogenic effects of a xenogeneic vascular endothelial cell growth factor (VEGF) vaccine in pet dogs with spontaneous cancer. Nine dogs with soft tissue sarcoma were immunized with a recombinant human VEGF vaccine over a 16-week period. The effects of immunization on antibodies to human and canine VEGF, circulating VEGF concentrations, tumor microvessel density (MVD), and tumor growth were assessed. The xenogeneic VEGF vaccine was well-tolerated by all dogs and resulted in induction of humoral responses against both human and canine VEGF in animals that remained in the study long enough to receive multiple immunizations. Three of five multiply immunized dogs also experienced sustained decreases in circulating plasma VEGF concentrations and two dogs had a significant decrease in tumor MVD. The overall tumor response rate was 30% for all treated dogs in the study. We conclude therefore that a xenogeneic VEGF vaccine may be a safe and effective alternative means of controlling tumor growth and angiogenesis.

Genetic control of VEGF and TGF-beta1 gene polymorphisms in childhood urinary tract infection and vesicoureteral reflux

We investigated whether genetic polymorphisms of vascular endothelial growth factor (VEGF) and transforming growth factor-beta1 (TGF-beta1), potential candidate genes in the pathogenesis of urinary tract infection (UTI) and vesicoureteral reflux (VUR), are associated with the susceptibility to UTI and VUR, and renal scarring. We recruited 89 controls and 86 UTI and 58 VUR children. The UTI group was subdivided into two groups according to renal scarring. Two polymorphisms of VEGF and three of TGF-beta1 genes were investigated by using PCR-restriction fragment length polymorphism analysis. In both UTI and VUR groups, there was an increase in frequency of the VEGF -460 CC (control, 4.3; UTI, 15.9; VUR, 17.8%; p < 0.05), TGF-beta1 -509 CC (control, 8.7; UTI, 34.6; VUR, 35.1%; p < 0.001), and TGF-beta1 -800 GG genotypes (control, 19.1; UTI, 40.5; VUR, 40.4%; p < 0.05). An increase in the TGF-beta1 +869 CC (scar-positive, 35.4; scar-negative, 10.3%; p < 0.05) and a decrease in the +869 TC genotype (scar-positive, 29.2; scar-negative, 55.2%; p < 0.05) were observed in the scar-positive subjects. There were no differences in +405 VEGF genotype frequencies. The VEGF T-460C and the TGF-beta1 C-509T, G-800A, and T869C polymorphisms could be genetic markers of the process of UTI and VUR.

VEGF C-634G polymorphism is associated with protection from isolated ventricular septal defect: case-control and TDT studies

The ventricular septal defect (VSD) is the most common congenital heart defect and no candidate susceptibility gene has been identified. Endocardial cushion and outflow septal morphogenesis, malalignment of which induces VSD, have been suggested to be mediated by the vascular endothelial growth factor (VEGF). Three single-nucleotide polymorphism (SNP) variants in promoter and 5'-UTR region of the VEGF gene, C-2578A (rs699947), G-1154A (rs1570360) and G-634C (rs2010963), were reported to alter its expression. We assessed the association in a Chinese population between these SNPs and VSD using a double approach: case-control and TDT designs. Among the three SNPs, only -634C allele was less frequently present in 222 patients compared to 352 controls (odds ratio: 0.76, 95% CI: 0.59-0.97, X(2)=5.06, P=0.024, not significant after a Bonferroni correction). This was significantly less transmitted to VSD patients (trios: 142) (odds ratio: 0.39, 95% CI: 0.25-0.62, X(2)=8.11, df=1, P=0.004, corrected P=0.024). A similar result was observed for haplotype -2578C/-1154G/-634C allele in both studies (in TDT: X(2)=7.51, df=1, P=0.006, corrected P=0.048). All these associations for the first time demonstrated that -634C allele was in a significant protective association against VSD, suggesting that VEGF dysregulation was involved in the pathological processes of VSD.

Increased Serum Vascular Endothelial Growth Factor Following Major Surgical Injury

OBJECTIVES

Vascular endothelial growth factor (VEGF) plays an important role in angiogenesis. We evaluated the changes in serum levels of VEGF following major surgical trauma and postoperative inflammatory complications.

MATERIALS AND METHODS

The serum concentration of VEGF was measured with enzyme-linked immunosorbent assay in 41 patients with esophageal cancer who underwent right transthoracic esophagectomy with extensive lymphadenectomy and in 13 patients with gallstones who underwent less-invasive laparoscopic cholecystectomy for comparison. Serum and plasma samples were obtained before the operation and on postoperative days (PODs) 1, 7, 14, 21, and 28. The changes in serum VEGF levels were compared among groups categorized by age, sex, blood loss volume during operation, amount of transfusion, pathological stage of the tumor, and postoperative inflammatory complications. The correlation between serum VEGF levels and inflammatory factors, such as peripheral blood cell count, interleukin-6 (IL-6), C-reactive protein (CRP), and severity of postoperative inflammatory complications, was also investigated. Furthermore, because platelets are a potential source of serum VEGF, platelet-poor plasma (PPP) was prepared from plasma samples, and the VEGF concentration in PPP was measured to compare with those in sera.

RESULTS

Serum VEGF levels increased significantly postoperatively. After reaching maximal levels on POD 14, VEGF levels gradually decreased until POD 28. The increase in the tranthoracic esophagectomy group was approximately twice that in laparoscopic cholecystectomy group on POD 14. Serum VEGF levels were not correlated with sex, age, blood loss, amount of transfusion, or tumor stage. However, serum VEGF levels were significantly higher in patients with postoperative inflammatory lung complications than in patients without such complications, and the maximal level of serum VEGF correlated with the severity of postoperative lung complications. However, there were no significant correlations between the increase in the level of serum VEGF and that of serum IL-6 or CRP. The increase of platelet counts in the peripheral blood correlated with that of the serum VEGF level, and VEGF levels in PPP were significantly lower than those in sera.

CONCLUSIONS

Serum VEGF levels increased in the angiogenesis phase of wound healing following major surgical injury. Platelets are a potential source of increased serum VEGF levels, whereas inflammatory lung complications might also be related to increased serum VEGF levels.

Major abdominal surgery increases plasma levels of vascular endothelial growth factor: open more so than minimally invasive methods

INTRODUCTION

Vascular endothelial growth factor (VEGF) is a potent inducer of angiogenesis that is necessary for wound healing and also promotes tumor growth. It is anticipated that plasma levels would increase after major surgery and that such elevations may facilitate tumor growth. This study's purpose was to determine plasma VEGF levels before and early after major open and minimally invasive abdominal surgery.

METHODS

Colorectal resection for cancer (n = 139) or benign pathology (n = 48) and gastric bypass for morbid obesity (n = 40) were assessed. Similar numbers of open and laparoscopic patients were studied for each indication. Plasma samples were obtained preoperatively and on postoperative days (POD) 1 and 3. VEGF levels were determined via ELISA. The following statistical methods were used: Fisher exact test, unmatched Student t test, Wilcoxon's matched pairs test, and the Mann Whitney U Test with P < 0.05 considered significant.

RESULTS

The mean preoperative VEGF level of the cancer patients was significantly higher than baseline level of benign colon patients. Regardless of indication or surgical method, on POD3, significantly elevated mean VEGF levels were noted for each subgroup. In addition, on POD1, open surgery patients for all 3 indications had significantly elevated VEGF levels; no POD1 differences were noted for the closed surgery patients. At each postoperative time point for each procedure and indication, the open group's VEGF levels were significantly higher than that of the matching laparoscopic group. VEGF elevations correlated with incision length for each indication.

CONCLUSION

As a group colon cancer patients prior to surgery have significantly higher mean VEGF levels than patients without tumors. Also, both open and closed colorectal resection and gastric bypass are associated with significantly elevated plasma VEGF levels early after surgery. This elevation is significantly greater and occurs earlier in open surgery patients. The duration and clinical importance of this finding is uncertain but merits further study.

Vascular endothelial growth factor levels in serum and plasma from patients undergoing controlled ovarian hyperstimulation for IVF

BACKGROUND

Vascular endothelial growth factor (VEGF) has been investigated as a marker of ovarian response to controlled ovarian hyperstimulation and as a predictor of ovarian hyperstimulation syndrome (OHSS) in IVF cycles. In most studies, serum has been used for circulating VEGF concentration measurement, but it has been suggested that plasma is the preferred medium to measure VEGF levels because of the potential contribution of VEGF released from platelets during blood clotting. This study investigated VEGF concentrations in paired serum and plasma samples from patients undergoing controlled ovarian hyperstimulation for IVF.

METHODS

Serum and plasma VEGF levels, as well as the number of platelets, were measured in 30 IVF patients who comprised three study groups delineated according to the estradiol (E(2)) serum concentration reached on the day of HCG administration: 10 patients having low E(2) serum levels (<1500 pg/ml, group L), 10 patients having intermediate E(2) serum levels (1500-3000 pg/ml, group I) and 10 patients having high E(2) serum levels (>3000 pg/ml, group H).

RESULTS

There was a statistically significant correlation between plasma and serum VEGF levels (rho = 0.61; P < 0.005) for the entire population studied, although serum values were higher by a factor of approximately 6-fold. No significant correlation was found between peripheral blood VEGF concentrations and serum E(2) or follicle number on HCG day or the number of oocytes collected. Similarly, paired serum and plasma VEGF measurements did not correlate with platelet count.

CONCLUSIONS

Serum and plasma VEGF concentrations are strongly correlated in paired samples from infertile patients undergoing controlled ovarian hyperstimulation. However, neither serum nor plasma VEGF levels were correlated with parameters associated with ovarian follicular activity. Peripheral blood VEGF levels were not correlated with platelet count.

Effect of heparin on blood vascular endothelial growth factor levels in patients with ST-elevation acute myocardial infarction undergoing primary percutaneous coronary intervention

It has been demonstrated that high blood vascular endothelial growth factor (VEGF) levels in patients with myocardial infarction decrease rapidly after reperfusion, possibly in response to heparin administration. We measured serum VEGF concentration before and after heparin infusion in 105 patients with ST-elevation acute myocardial infarction (STEMI) who underwent primary percutaneous coronary intervention (PCI). Serum VEGF concentration in patients with STEMI was significantly higher than in healthy controls. After PCI, the concentration of VEGF decreased by approximately 70%, with the greatest decrease seen in patients with the highest initial VEGF levels. To determine whether heparin could decrease VEGF concentration by sequestering VEGF in the endothelium, a fixed dose of recombinant VEGF was incubated for 40 minutes with EA.hy926 endothelial cells in vitro. Recovery of VEGF from medium after culture was decreased by up to 15% with increasing doses of heparin. Concentration of VEGF did not change in the absence of heparin and/or endothelial cells. In conclusion, these results suggest that a rapid decrease in blood VEGF after PCI may be related to the administration of heparin, which binds simultaneously to VEGF and endothelial cells.

Vascular endothelial growth factor (VEGF) in acute lung injury (ALI) and acute respiratory distress syndrome (ARDS): paradox or paradigm?

Acute respiratory distress syndrome (ARDS), the most severe form of acute lung injury (ALI), remains a devastating condition with a high mortality. It is characterised by alveolar injury and increased pulmonary vascular permeability. Vascular endothelial cell growth factor (VEGF) was identified by its properties to increase permeability and act as a cellular growth factor, hence its potential for a key role in the pathogenesis of ALI/ARDS. This review describes the basic biology of VEGF and its receptors as an essential prerequisite to discussing the available and sometimes paradoxical published data, before considering a paradigm for the role of VEGF in the human lung.

Preoperative plasma vascular endothelial growth factor but not nitrite is a useful complementary tumor marker in patients with colorectal cancer

PURPOSE

Vascular endothelial growth factor and nitric oxide are both related to tumor progression. This study was designed to measure preoperative plasma vascular endothelial growth factor and nitrite levels in patients with colorectal cancer to evaluate their clinical applications as tumor markers.

METHODS

In total, 279 patients with primary colorectal cancer and 20 patients with hemorrhoids (as a control) were included in this study. Plasma vascular endothelial growth factor was measured by quantitative, solid-phase, enzyme-linked immunosorbent assay (R&D Systems), whereas nitrite was measured by a high-performance liquid chromatographic method.

RESULTS

The vascular endothelial growth factor (mean, 220.6 pg/ml, P < 0.005) and nitrite (mean, 29.4 microM, P = 0.043) levels of patients with cancer were significantly higher than those of controls (mean vascular endothelial growth factor, 67 pg/ml; mean nitrite, 23 microM). Preoperative plasma vascular endothelial growth factor levels were positively correlated with tumor stage, T class, M class, and tumor size (Spearman correlation, P < 0.01), but were not associated with gender, N class, tumor location, histology type, or grade. There were no statistical differences in nitrite levels among different groups of patients with cancer. Higher vascular endothelial growth factor levels also were correlated with leukocytosis, elevated carcinoembryonic antigen, and a higher platelet count. The positive rates of vascular endothelial growth factor elevation (>148.6 pg/ml) compared with carcinoembryonic antigen elevation were 36.9 to 14.6 percent in Stage I, 60.9 to 33 percent in Stage II, 62.9 to 48.7 percent in Stage III, and 86 to 70.2 percent in Stage IV, respectively. The overall positive rate of vascular endothelial growth factor elevation also was higher than that of carcinoembryonic antigen elevation (63 percent for vascular endothelial growth factor vs. 42.5 percent for carcinoembryonic antigen, P = 0.016). More than one-half of the patients without carcinoembryonic antigen elevation still had elevated vascular endothelial growth factor levels. The combined assessment using vascular endothelial growth factor and carcinoembryonic antigen was superior to individual assessment using vascular endothelial growth factor or carcinoembryonic antigen. In node-negative tumor, the patients with vascular endothelial growth factor elevation had worse disease-free survival than those without vascular endothelial growth factor elevation (P = 0.0367). There was no association of vascular endothelial growth factor elevation with survival in patients with node-positive tumor.

CONCLUSIONS

Plasma vascular endothelial growth factor is a useful complementary tumor marker; however, synchronous measurement of white blood cells, platelets, and carcinoembryonic antigen is suggested in the clinical application of vascular endothelial growth factor to colorectal cancer.

Angiogenesis in non-small cell lung cancer: The prognostic impact of neoangiogenesis and the cytokines VEGF and bFGF in tumours and blood

BACKGROUND

Due to a dismal prognosis of advanced lung cancer, novel screening tools and more effective treatments are clearly needed. Lately, an increasing number of tumour-released angiogenic cytokines which affect vessel formation, tumour growth, invasion, and metastasis have been identified. Vascular endothelial growth factors (VEGFs) and basic fibroblast growth factor (bFGF) are among the most important angiogenic factors. Based on available literature, we have explored the mechanisms of angiogenesis and its prognostic significance in non-small cell lung cancer, estimated by microvessel density (MVD) and the presence of VEGF and bFGF in the tumour and blood from NSCLC patients.

METHODS

Several comprehensive Pubmed searches for the period January 1993 to May 2005 were performed using strategic combinations of the terms non-small cell lung cancer, angiogenesis, vascular endothelial growth factor, basic fibroblast growth factor, tumour expression, microvessel density, circulating, and serum.

RESULTS

NSCLC neoangiogenesis, as measured by MVD, and tumour expression of VEGF are poor prognostic factors for survival (MVD, HR 1.8-2.0; VEGF, HR 1.5). bFGF tumour expression is also associated with poor survival and more aggressive disease. When evaluating the prognostic impact of elevated VEGF levels in blood, 10 of 16 studies (63%) indicated a negative prognostic impact. Of five studies on the prognostic value of circulating bFGF, three studies reported a negative prognostic impact, while one indicated bFGF as a good prognostic factor and one was inconclusive.

CONCLUSION

Angiogenic factors are poor prognostic indicators for tumour aggressiveness and survival in NSCLC. Assessments of circulating levels of VEGF and possibly bFGF may be valuable future tools for treatment planning and monitoring of treatment effect and relapse. First, however, these blood tests need to be standardised and validated in large-scale prospective clinical trials.

Changes in circulating mesenchymal stem cells, stem cell homing factor, and vascular growth factors in patients with acute ST elevation myocardial infarction treated with primary percutaneous coronary intervention

OBJECTIVE

To investigate the spontaneous occurrence of circulating mesenchymal stem cells (MSC) and angiogenic factors in patients with ST elevation acute myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI).

DESIGN

In 20 patients with STEMI, blood samples were obtained on days 1, 3, 7, 14, 21, and 28 after the acute PCI. Fifteen patients with a normal coronary angiography formed a control group. MSC (CD45-/CD34-), plasma stromal derived factor 1 (SDF-1), vascular endothelial growth factor A (VEGF-A), and fibroblast growth factor 2 (FGF-2) were measured by multiparametric flow cytometry and enzyme linked immunosorbent assay (ELISA).

RESULTS

Circulating CD45-/CD34- cells were significantly decreased on day 7 compared with day 3. Cell counts normalised one month after the acute onset of STEMI. The changes were mainly seen in patients with a large infarction. Plasma SDF-1 increased significantly from day 3 to day 28, and VEGF-A and FGF-2 increased significantly from day 7 to day 28.

CONCLUSIONS

Spontaneous sequential fluctuations in MSC and the increase in vascular growth factor concentrations after STEMI suggest that the optimal time for additional stem cell therapy is three weeks after a myocardial infarction to obtain the maximum effects by stimulating endogenous growth factors on the delivered stem cells.

Met identification on human platelets: role of hepatocyte growth factor in the modulation of platelet activation

Circulating HGF is significantly increased in a number of thrombus-associated disorders. Since platelets play a pivotal role in thrombogenesis, the ability of HGF to interact with human platelets was investigated. This paper shows for the first time that human platelets express HGF receptor, the tyrosine kinase encoded by c-MET gene. At physiological concentrations HGF was found to inhibit both glycoprotein (alpha)IIb(beta)3 activation and thrombin-dependent platelet aggregation in a dose- and time-dependent manner. These results suggest that circulating HGF may counteract thrombogenesis by negatively modulating platelet functions.

Vascular endothelial growth factor (VEGF) in physiological and pathological conditions

Vascular endothelial growth factor (VEGF) is the major endothelial-cell specific stimulatory factor regarded as the most important positive regulator of angiogenesis and vascular permeability. Due to its powerful angiogenic and mitogenic properties, VEGF takes part in a variety of crucial biological processes, including wound repair and tumorigenesis. The elevated expression of VEGF and its receptors has been found in malignancies of various origin as being associated with metastasis formation and poor prognosis. Recently, some possibilities appeared to block the VEGF action when it is undesirable or promote its activity when it can be useful. These new therapeutic strategies based upon the knowledge of VEGF biological role, are being tried and up till now they proved to be successful, especially in anticancer therapy and the coronary heart disease treatment.

Serum Levels of Macrophage Colony Stimulating, Vascular Endothelial, and Placenta Growth Factor in Relation to Later Clinical Onset of Pre-Eclampsia and a Small-for-Gestational Age Birth

PROBLEM

The multisystem disorder of pre-eclampsia (PE) becomes manifest in late gestation, but the pathology originates in early pregnancy by the deleterious action of placental substances to the maternal endothelial system. These factors were searched for in the attempt to identify, as early as possible, the pregnancies with an increased risk of developing pre-eclampsia. The literature is equivocal regarding the usefulness of various markers including vascular endothelial growth factor (VEGF) and macrophage colony-stimulating factor (M-CSF). Results are often confounded by a varying fraction of pregnancies affected by foetal growth restriction (FGR) amongst the case and control groups.

METHOD OF STUDY

In a nested case-control study we compared the serum levels of M-CSF, VEGF, and placenta growth factor (PLGF) in 23 pregnancies with subsequent mild PE without FGR and nine FGR pregnancies without PE with 40 matched controls at 17, 25, and 33 weeks of gestation cross-sectionally and longitudinally.

RESULTS

VEGF levels were reduced in FGR but not in subsequently pre-eclamptic pregnancies at 17, 25, and 33 weeks. In contrast, PLGF was reduced in the PE but not in the FGR group. M-CSF did not differ between the three groups.

CONCLUSION

Depending on which growth factor is found to be reduced, an early distinction can be made in terms of an increased risk for PE or FGR. Inconsistencies in the literature may reflect differences in PE disease severity between studies and the presence of a varying fraction of cases with FGR.

VEGF -460 genotype plays an important role in progression to chronic kidney disease stage 5

BACKGROUND

Changes in renal vasculature, with vascular and interstitial fibrosis, are hallmarks of progression to chronic kidney disease (CKD) stage 5. Vascular endothelial growth factor (VEGF) is a potent angiogenic and vascular permeability factor. Transforming growth factor-beta1 (TGF-beta1) plays a critical role in promoting extracellular matrix (ECM) deposition and fibrosis. This study investigates whether genetic polymorphisms of VEGF or TGF-beta1 are associated with (i) progressive decline in renal function in patients with glomerular disorders (cohort 1) and (ii) predisposition to CKD stage 5 in a separate group of renal transplant recipients with various primary diseases (cohort 2).

METHODS

Two patient groups were studied. Cohort 1 comprised 91 patients with biopsy-proven glomerular disease who were followed-up for 5 years before categorization as either non-progressors (with stable serum creatinine or < or =30% increase over 5 years, n = 39) or progressors (requiring dialysis, transplantation or whose serum creatinine increased by >30% over 5 years, n = 52). Cohort 2 comprised 107 patients with various primary renal diseases, who had reached CKD stage 5 and undergone renal transplantation at the time of study. All patients were genotyped for the VEGF polymorphisms at positions -460 (C/T) and +405 (G/C). Linkage disequilibrium (LD) was established using EHplus. SNPHAP was used to estimate haplotype frequency and to infer haplotypes to all patients. Cohort 1 patients were genotyped for the TGF-beta1 polymorphisms at positions -800, -509, codons 10 and 25. Genotyping was performed by polymerase chain reaction-restriction length polymorphism (PCR-RFLP).

RESULTS

In cohort 1, there was a significant increase in frequency of the -460 VEGF CC genotype 30.8 vs 5.1%, P = 0.008; odds ratio (OR), CC vs TT 10.67, 95% confidence interval (CI), 1.94-58.72 and C allele 56.7 vs 37.2%, P = 0.009; OR 2.22, 95% CI, 1.21-4.04, in the progressor patients when compared with the non-progressors. In cohort 2, there was a significant increase in the VEGF -460 CC genotype when compared with healthy volunteers 37 vs 20.8%, P = 0.011; OR CC vs TT 1.59, 95% CI, 0.72-3.51. The -460 and +405 polymorphisms were in LD P < 0.00007. There were significant differences in diplotype (haplotype pair) frequencies in cohort 1 and 2, P = 0.018, which confirmed the importance of the -460C allele. There were no associations between the VEGF +405 or TGF-beta1 polymorphisms and progressive renal disease.

CONCLUSION

In this study, we have demonstrated an association between the VEGF -460 polymorphism and progression to CKD stage 5. The function of this polymorphism remains unclear although previous evidence suggests that promoter constructs containing this single nucleotide polymorphism (SNP) have been associated with increased activity. Clearly there is a role for TGF-beta1 in chronic kidney disease. However, this study found no associations with four TGF-beta1 polymorphisms in this cohort.

Vascular endothelial growth factor and insulin-like growth factor-1 in polycystic ovary syndrome and their relation to ovarian blood flow

OBJECTIVES

(1) To determine the serum levels of vascular endothelial growth factor (VEGF) and insulin-like growth factor-1 (IGF-1) in women with polycystic ovary syndrome (PCOS). (2) To study Doppler blood flow changes within the ovarian stroma of women with PCOS. (3) To evaluate the relationship between VEGF and IGF-1 and Doppler indices as well as hormonal profile.

SETTING

Department of Obstetrics and Gynecology, and Department of Biochemistry, Faculty of Medicine, Assiut University, Egypt.

DESIGN

Cross-sectional study.

PATIENTS AND METHODS

Fifty infertile women with PCOS diagnosed by ultrasound examination and a history of oligomenorrhea, hirsutism and obesity were studied. Serum levels of vascular endothelial growth factor (VEGF), insulin-like growth factor-1 (IGF-1) and hormonal profile were measured. Doppler blood flow velocity waveforms analysis in both right and left intraovarian arteries was done. Twenty healthy and fertile women with regular menstrual cycles served as a comparison group were similarly studied at the third day of the cycle.

RESULTS

The serum levels of VEGF, IGF-1 (4.79 +/- 0.91, 253.15 +/- 70.07 versus 2.39 +/- 0.42, 186.65 +/- 42.7) were significantly elevated (P <0.001 and P <0.01, respectively) in women with PCOS compared with control. Doppler indices, PI (2.01 +/- 0.77, 2.66 +/- 1.00 versus 2.98 +/- 0.77, 3.75 +/- 0.98) and RI (0.77 +/- 0.12, 0.82 +/- 0.09 versus 0.87 +/- 0.09, 0.89 +/- 0.09) in both right and left intraovarian vessels were significantly lower in the patients than controls. The VEGF and IGF-1 levels were negatively correlated with RI and PI in the uterine and intraovarian arteries. VEGF level was positively correlated with IGF-1 (r=0.41, P <0.05) in women with PCOS.

CONCLUSIONS

Higher serum levels of VEGF and IGF-1 in PCOS women may be related to the increased vascularity that underlies the increased blood flow demonstrated by Doppler blood flow measurements in these women.

Pathogenesis of high altitude pulmonary edema: does alveolar epithelial lining fluid vascular endothelial growth factor exacerbate capillary leak?

Vascular endothelial growth factor (VEGF) is a potent mediator of capillary leak if it gains access to its receptors on the capillary endothelium. We have observed that there are high levels of VEGF compartmentalized in the alveolar epithelial lining fluid of normal humans at levels 500-fold greater than plasma. The potential for high altitude to result in compromise of alveolar epithelial tight junctions and experimental animal studies in which pulmonary edema is induced when VEGF is overexpressed in the alveolar epithelium, suggest a mechanism. We hypothesize that when the epithelial barrier is compromised at high altitude the normally high level of VEGF in the alveolar epithelial fluid has access to the pulmonary endothelium, where it acutely alters permeability, markedly exacerbating the high permeability pulmonary edema that characterizes high altitude pulmonary edema. If correct, this paradigm opens the possibility of testing available anti-VEGF therapies to treat this potentially fatal disorder.

Clinical significance of serum levels of vascular endothelial growth factor and its receptor in biliary disease and carcinoma

AIM: To investigate the clinical significance of serum vascular endothelial growth factor (VEGF) and soluble VEGF receptor-1 (VEGFR1/Flt-1) (sVEGFR1) levels in biliary diseases.

METHODS: We analyzed the serum levels of these proteins in patients with acute cholangitis (group 1), biliary malignancies (group 2), and primary biliary cirrhosis or primary sclerosing cholangitis (group 3), and in healthy donors (group 4). The influence of inflammation was also analyzed. Serum VEGF levels were expressed as VEGF per platelet (VEGF/PLT, pg/10⁶) in order to exclude the influence of platelet counts.

RESULTS: sVEGFR1 levels were significantly higher in groups 1 and 2 than in the control group, but did not correlate with inflammatory markers. VEGF/PLT levels were generally higher in patients with active inflammation than in those with carcinoma. C-reactive protein strongly correlated with the levels of serum VEGF independently of platelet and leukocyte counts, even in cancer patients. In cancer patients, VEGF/PLT and sVEGFR1 levels might be indicators for evaluating the effect of medical treatment or the disease progression.

CONCLUSION: Serum VEGF and VEGFR1 might be useful markers for gauging the clinical effect of various treatments on patients.

Circulating plasma levels of vascular endothelial growth factor in patients with sleep disordered breathing

INTRODUCTION

Cellular vascular endothelial growth factor (VEGF) expression is increased in response to regional hypoxia, however, contradictory results were reported on the effects of systemic hypoxemia on circulating VEGF levels. This study investigated plasma concentrations of VEGF in patients with a variable degree of overnight hypoxemia due to sleep disordered breathing (SDB).

METHODS

VEGF levels were assessed by ELISA in non-activated (VEGFbl) and thrombin stimulated platelet rich plasma (VEGFprp) of 45 patients with SDB: Group 1 patients with obstructive sleep apnea and an apnea-hypopnea index (AHI) > 15/h; Group 2 subjects with an AHI < 5/h; Group 3 patients on CPAP treatment for sleep apnea.

RESULTS

39 patients were included in the final analysis. Patients in Group 1 had a higher %time of sleep with SaO2 <90% and a significantly lower mean and minimum overnight oxygen saturation than subjects in Group 2 and patients in Group 3 (P<0.05). Despite significant differences in overnight oxygenation, VEGFbl and VEGFprp concentrations were not significantly different between the three study groups. However, plasma levels of VEGFbl were significantly higher (P = 0.02) in SDB patients with arterial hypertension (n = 19; VEGFbl: 14.0+/-3.3 pg/ml) than in those without arterial hypertension (n = 20; VEGFbl: 10.9+/-5.2 pg/ml). There were no relationships between VEGF levels and polysomnographic oxygenation parameters. In univariate analysis we observed significant relationships for VEGFbl with BMI (C: 0.393; P<0.05) and serum fibrinogen (C: 0.399; P<0.05).

CONCLUSIONS

Circulating plasma VEGF levels in patients with sleep disordered breathing may be unrelated to night time hypoxemia (257 Words).

Plasma vascular endothelial growth factor and serum soluble angiopoietin receptor sTIE-2 in patients with dural arteriovenous fistulas: a pilot study

Our aim was to correlate concentrations of circulating vascular endothelial growth factor (VEGF) and serum soluble angiopoietin receptor (sTIE-2) before and after endovascular treatment with the grading in human dural arteriovenous fistulas (DAVFs). In ten patients with DAVFs undergoing diagnostic cerebral angiography and endovascular intervention, pre-treatment and post-treatment levels of plasma VEGF and serum TIE-2 were examined in a prospective study design. A total of 32 plasma samples and 19 serum samples was collected from the cubital vein, the arterial sheath before and--if applicable--after intervention. Plasma VEGF and serum Tie-2 levels were measured by standardized ELISA protocols. In eight of ten patients with DAVF increased circulating VEGF levels (elevation of more than mean + 2 SD of published normal values) were found, whereas two patients showed increased sTIE-2 levels. Six of the seven patients treated by endovascular embolization displayed a post-interventional decrease of VEGF values. The serum TIE-2 levels decreased slightly after intervention. Pre-treatment vVEGF levels varied significantly between patients with grades I and II/III fistulas according to the Cognards classification system. Our pilot study suggests that assessment of angiogenesis parameters in patients with DAVFs might correlate with the DAVFs' grade. To support the hypothesis that a change in angiogenic indicators may serve as indicators for a response to therapy, a larger number of patients should be followed for a longer time period.