Plasma and platelet-derived vascular endothelial growth factor and angiopoietin-1 in hypertension: effects of antihypertensive therapy

Influence of dabigatran on pro-inflammatory cytokines, growth factors and chemokines - Slowing the vicious circle of coagulation and inflammation

AIMS

Blood coagulation is one of the most important host-defending mechanisms in vivo by maintaining the blood pressure after injury. However, besides maintaining homeostasis, blood coagulation and the contributing factors are directly linked to pathological conditions, such as thromboembolism and inflammation, leading to cardiovascular diseases, among others. As anti-inflammatory drugs may reduce cardiovascular events, we hypothesized in this study that the direct thrombin inhibitor dabigatran may reduce cytokine, growth factor and chemokine expression in vitro.

MAIN METHODS

Initially, human whole blood was incubated in tubes for serum, EDTA plasma, and heparinized plasma. Furthermore, human PBMCs were isolated and incubated under different culture conditions, including the treatment with human serum or thrombin, respectively. The effect of the oral anticoagulant dabigatran on pro-inflammatory cytokines, growth factors and chemokines was investigated by ELISA.

KEY FINDINGS

Conditioned serum resulted in a significant alteration of the secretome's protein levels after 24 h. However, solely ANG showed a dose-dependent increment by the addition of serum (79.8 ± 9.2 ng/mL) in comparison to baseline (0.2 ± 0.2 ng/mL), as it was in trend for thrombin treatment. Furthermore, the pre-treatment of PBMCs with different doses of dabigatran significantly lowered supernatant protein levels measured. Moreover, dabigatran was shown to decrease most notably the growth factor and chemokine levels in the PBMC's secretome that were treated with 200 ng/mL thrombin in a dose-dependent manner.

SIGNIFICANCE

In conclusion, novel oral anticoagulants, such as dabigatran, could help to reduce not only procoagulatory effects in inflammatory conditions but could also reduce proinflammatory stimuli via reduced expression of cytokines and chemokines.

Angiopoietin-1 aggravates atherosclerosis by inhibiting cholesterol efflux and promoting inflammatory response

OBJECTIVE

Angiopoietin-1 (Ang-1), a secreted protein, mainly regulates angiogenesis. Ang-1 has been shown to promote the development of atherosclerosis, whereas little is known about its effects on lipid metabolism and inflammation in this process.

METHOD

Ang-1 was transfected into ApoE^-/- mice via lentiviral vector or incubated with THP-1 derived macrophages. Oil red O and HE staining were performed to measure the size of atherosclerotic plaques in ApoE^-/- mice. Immunofluorescence was employed to show the expression of target proteins in aorta. [³H] labeled cholesterol was performed to examine the efficiency of cholesterol efflux and reverse cholesterol transport (RCT) both in vivo and vitro. Western blot and qPCR were used to quantify target proteins both in vivo and vitro. ELISA detected the levels of pro-inflammatory cytokines in mouse peritoneal macrophage.

RESULTS

Our data showed that Ang-1 augmented atherosclerotic plaques formation and inhibited cholesterol efflux. The binding of Ang-1 to Tie2 resulted in downregulation of LXRα, ABCA1 and ABCG1 expression via inhibiting the translocation of TFE3 into nucleus. In addition, Ang-1 decreased serum HDL-C levels and reduced reverse cholesterol transport (RCT) in ApoE-/- mice. Furthermore, Ang-1 induced lipid accumulation followed by increasing TNF-α, IL-6, IL-1β，and MCP-1 produced by MPMs, as well as inducing M1 phenotype macrophage marker iNOS and CD86 expression in aorta of ApoE^-/- mice.

CONCLUSION

Ang-1 has an adverse effect on cholesterol efflux by decreasing the expression of ABCA1 and ABCG1 via Tie2/TFE3/LXRα pathway, thereby promoting inflammation and accelerating atherosclerosis progression.

Potential Protective Role of Blood Pressure-Lowering Drugs on the Balance between Hemostasis and Fibrinolysis in Hypertensive Patients at Rest and During Exercise

In patients with hypertension, the triad represented by endothelial dysfunction, platelet hyperactivity, and altered fibrinolytic function disturbs the equilibrium between hemostasis and fibrinolysis and translates into a hypercoagulable state, which underlies the risk of thrombotic complications. This article reviews the scientific evidence regarding some biological effects of antihypertensive drugs, which can protect patients from the adverse consequences of hypertensive disease, improving endothelial function, enhancing antioxidant activity, and restoring equilibrium between hemostatic and fibrinolytic factors. These protective effects appear not to be mediated through blood pressure reduction and are not shared by all molecules of the same pharmacological class.

Angiopoietins bind thrombomodulin and inhibit its function as a thrombin cofactor

Angiopoietin-1 (Ang1) and Angiopoietin-2 (Ang2) are ligands for Tie2, an endothelial-specific receptor tyrosine kinase that is an essential regulator of angiogenesis. Here we report the identification, via expression cloning, of thrombomodulin (TM) as another receptor for Ang1 and Ang2. Thrombomodulin is an endothelial cell surface molecule that plays an essential role as a coagulation inhibitor via its function as a cofactor in the thrombin-mediated activation of protein C, an anticoagulant protein, as well as thrombin-activatable fibrinolysis inhibitor (TAFI). Ang1 and Ang2 inhibited the thrombin/TM-mediated generation of activated protein C and TAFI in cultured endothelial cells, and inhibited the binding of thrombin to TM in vitro. Ang2 appears to bind TM with higher affinity than Ang1 and is a more potent inhibitor of TM function. Consistent with a potential role for angiopoietins in coagulation, administration of thrombin to mice rapidly increased plasma Ang1 levels, presumably reflecting release from activated platelets (previously shown to contain high levels of Ang1). In addition, Ang1 levels were significantly elevated in plasma prepared from wound blood, suggesting that Ang1 is released from activated platelets at sites of vessel injury. Our results imply a previously undescribed role for angiopoietins in the regulation of hemostasis.

Plasma N-Terminal Probrain Natriuretic Peptide, Vascular Endothelial Growth Factor, and Cardiac Troponin I as Novel Biomarkers of Hypertensive Disease and Target Organ Damage in Cats

Background

In the absence of ocular target organ damage (ocular‐TOD), diagnosis of hypertension is challenging in cats. Biomarkers would provide additional support for the diagnosis of hypertension.

Hypothesis

Vascular endothelial growth factor (VEGF), N‐terminal probrain natriuretic peptide (NT‐proBNP), cardiac troponin I (cTnI), and urine protein‐to‐creatinine ratio (UPC) are predictors of systemic hypertension, will be increased in cats with hypertension with or without ocular‐TOD, and will decrease with antihypertensive treatment.

Methods

Plasma VEGF, NT‐proBNP, and cTnI concentrations and UPC were determined in healthy geriatric cats, normotensive cats with chronic kidney disease (CKD), hypertensive cats with evidence of hypertensive retinopathy (HT‐ocular‐TOD), and hypertensive cats without hypertensive ocular‐TOD (HT‐noTOD). Comparisons among groups were performed. Multivariable binary logistic regression models were built to identify independent biomarkers of hypertension and ocular‐TOD. Receiver operator characteristic (ROC) curves were drawn to assess clinical use.

Results

Cats with HT‐ocular‐TOD had significantly higher VEGF than all other groups (P < .05) and significantly higher NT‐proBNP than healthy cats (P < .001). Healthy cats had significantly lower cTnI than all other groups (P < .05). No differences were found among groups for UPC (P = .08). Cardiac troponin I and VEGF were independent predictors of hypertension (P < .05), but none of the biomarkers were independent predictors of ocular‐TOD. N‐terminal probrain natriuretic peptide concentrations decreased with antihypertensive treatment (P < .001). The ROC curves indicated that none of the biomarkers met the criteria to function as diagnostic tests for the diagnosis of hypertension or associated ocular‐TOD.

Conclusions and Clinical Significance

Despite statistical significance and changes with ocular‐TOD, antihypertensive treatment, or both, VEGF, NT‐proBNP, and cTnI did not function as useful diagnostic tests for hypertension. Persistently increased systolic blood pressure (SBP) measurements in combination with fundoscopy remains the preferred method for diagnosis of feline hypertension.

Circulating Angiopoietin-1 Is Not a Biomarker of Disease Severity or Prognosis in Pulmonary Hypertension

Background

Circulating angiopoietin-1 (Ang-1) has been linked to pulmonary hypertension (PH) in experimental studies. However, the clinical relevance of Ang-1 as a biomarker in PH remains unknown. We aimed to investigate the prognostic and clinical significance of Ang-1 in PH using data from the prospectively recruiting Giessen PH Registry.

Methods

Patients with suspected PH (without previous specific pulmonary arterial hypertension [PAH] therapy) who underwent initial right heart catheterization (RHC) in our national referral center between July 2003 and May 2012 and who agreed to optional biomarker analysis were included if they were diagnosed with idiopathic PAH, connective tissue disease-associated PAH (CTD-PAH), PH due to left heart disease (PH-LHD), or chronic thromboembolic PH (CTEPH), or if PH was excluded by RHC (non-PH controls). The association of Ang-1 levels with disease severity (6-minute walk distance and pulmonary hemodynamics) was assessed using linear regression, and the impact of Ang-1 levels on transplant-free survival (primary endpoint) and clinical worsening was assessed using Kaplan—Meier curves, receiver operating characteristic (ROC) analyses, and Cox regression.

Results

151 patients (39, 39, 32, and 41 with idiopathic PAH, CTD-PAH, PH-LHD, and CTEPH, respectively) and 41 non-PH controls were included. Ang-1 levels showed no significant difference between groups (p = 0.8), and no significant associations with disease severity in PH subgroups (p ≥ 0.07). In Kaplan—Meier analyses, Ang-1 levels (stratified by quartile) had no significant impact on transplant-free survival (p ≥ 0.27) or clinical worsening (p ≥ 0.51) in PH subgroups. Regression models found no significant association between Ang-1 levels and outcomes (p ≥ 0.31). ROC analyses found no significant cut-off that would maximize sensitivity and specificity.

Conclusions

Despite a strong pathophysiological association in experimental studies, this first comprehensive analysis of Ang-1 in PH subgroups suggests that Ang-1 is not a predictive and clinically relevant biomarker in PH.

Fruitflow®: the first European Food Safety Authority-approved natural cardio-protective functional ingredient

Hyperactive platelets, in addition to their roles in thrombosis, are also important mediators of atherogenesis. Antiplatelet drugs are not suitable for use where risk of a cardiovascular event is relatively low. It is therefore important to find alternative safe antiplatelet inhibitors for the vulnerable population who has hyperactive platelets in order to reduce the risk of cardiovascular disease. Potent antiplatelet factors were identified in water-soluble tomato extract (Fruitflow^®), which significantly inhibited platelet aggregation. Human volunteer studies demonstrated the potency and bioavailability of active compounds in Fruitflow^®. Fruitflow^® became the first product in Europe to obtain an approved, proprietary health claim under Article 13(5) of the European Health Claims Regulation 1924/2006 on nutrition and health claims made on foods. Fruitflow^® is now commercially available in different countries worldwide. In addition to its reduction in platelet reactivity, Fruitflow^® contains anti-angiotensin-converting enzyme and anti-inflammatory factors, making it an effective and natural cardio-protective functional food.

P-selectin and subclinical and clinical atherosclerosis: the Multi-Ethnic Study of Atherosclerosis (MESA)

OBJECTIVE

P-selectin is a cellular adhesion molecule that has been shown to be crucial in development of coronary heart disease (CHD). We sought to determine the role of P-selectin on the risk of atherosclerosis in a large multi-ethnic population.

METHODS

Data from the Multi-Ethnic Study of Atherosclerosis (MESA), including 1628 African, 702 Chinese, 2393 non-Hispanic white, and 1302 Hispanic Americans, were used to investigate the association of plasma P-selectin with CHD risk factors, coronary artery calcium (CAC), intima-media thickness, and CHD. Regression models were used to investigate the association between P-selectin and risk factors, Tobit model for CAC, and Cox regression for CHD events.

RESULTS

Mean levels of P-selectin differed by ethnicity and were higher in men (P<0.001). For all ethnic groups, P-selectin was positively associated with measures of adiposity, blood pressure, current smoking, LDL, and triglycerides and inversely with HDL. A significant ethnic interaction was observed for the association of P-selectin and prevalent diabetes; however, P-selectin was positively associated with HbA1c in all groups. Higher P-selectin levels were associated with greater prevalence of CAC. Over 10.1 years of follow-up, there were 335 incident CHD events. There was a positive linear association between P-selectin levels and rate of incident CHD after adjustment for traditional risk factors. However, association was only significant in non-Hispanic white Americans (HR: 1.81, 95% CI 1.07 to 3.07, P=0.027).

CONCLUSION

We observed ethnic heterogeneity in the association of P-selectin and risk of CHD.

Maternal and fetoplacental hypoxia do not alter circulating angiogenic growth effectors during human pregnancy

One causal model of preeclampsia (PE) postulates that placental hypoxia alters the production of angiogenic growth effectors (AGEs), causing an imbalance leading to maternal endothelial cell dysfunction. We tested this model using the natural experiment of high-altitude (HA) residence. We hypothesized that in HA pregnancies 1) circulating soluble fms-like tyrosine kinase 1 (sFlt-1) is increased and placental growth factor (PlGF) decreased, and 2) AGE concentrations correlate with measures of hypoxia. A cross-sectional study of healthy pregnancies at low altitude (LA) (400 m) versus HA (3600 m) compared normal (n = 80 at HA, n = 90 at LA) and PE pregnancies (n = 20 PE at HA, n = 19 PE at LA). Blood was collected using standard serum separation and, in parallel, by a method designed to inhibit platelet activation. AGEs were measured by enzyme-linked immunosorbent assays. AGEs did not differ between altitudes in normal or PE pregnancies. AGE concentrations were unrelated to measures of maternal or fetal hypoxia. PlGF was lower and sFlt-1 higher in PE, but overlapped considerably with the range observed in normal samples. PlGF correlated with placental mass in both normal and PE pregnancies. The contribution of peripheral cells to the values measured for AGEs was similar at LA and HA, but was greater in PE than in normotensive women. Hypoxia, across a wide physiological range in pregnancy, does not alter levels of circulating AGEs in otherwise normal pregnancies. Peripheral cell release of AGEs with the hemostasis characteristic of standard blood collection is highly variable and contributes to a doubling of the amount of sFlt-1 measured in PE as compared to normal pregnancies.

Between candidate genes and whole genomes: time for alternative approaches in blood pressure genetics

Blood pressure has a significant genetic component, but less than 3% of the observed variance has been attributed to genetic variants identified to date. Candidate gene studies of rare, monogenic hypertensive syndromes have conclusively implicated several genes altering renal sodium balance, and studies of essential hypertension have inconsistently implicated over 50 genes in pathways affecting renal sodium balance and other functions. Genome-wide linkage scans have replicated numerous quantitative trait loci throughout the genome, and over 50 single nucleotide polymorphisms (SNPs) have been replicated in multiple genome-wide association studies. These studies provide considerable evidence that epistasis and other interactions play a role in the genetic architecture of blood pressure regulation, but candidate gene studies have limited scope to test for epistasis, and genome-wide studies have low power for both main effects and interactions. This review summarizes the genetic findings to date for blood pressure, and it proposes focused, pathway-based approaches involving epistasis, gene-environment interactions, and next-generation sequencing to further the genetic dissection of blood pressure and hypertension.

Selectins and Associated Adhesion Proteins in Inflammatory disorders

Inflammation is defined as the normal response of living tissue to injury or infection. It is important to emphasize two components of this definition. First, that inflammation is a normal response and, as such, is expected to occur when tissue is damaged. Infact, if injured tissue does not exhibit signs of inflammation this would be considered abnormal and wounds and infections would never heal without inflammation. Secondly, inflammation occurs in living tissue, hence there is need for an adequate blood supply to the tissues in order to exhibit an inflammatory response. The inflammatory response may be triggered by mechanical injury, chemical toxins, and invasion by microorganisms, and hypersensitivity reactions. Three major events occur during the inflammatory response: the blood supply to the affected area is increased substantially, capillary permeability is increased, and leucocytes migrate from the capillary vessels into the surrounding interstitial spaces to the site of inflammation or injury. The inflammatory response represents a complex biological and biochemical process involving cells of the immune system and a plethora of biological mediators. Cell-to-cell communication molecules such as cytokines play an extremely important role in mediating the process of inflammation. Inflammation and platelet activation are critical phenomena in the setting of acute coronary syndromes. An extensive exposition of this complex phenomenon is beyond the scope of this article (Rankin 2004).

Five blood pressure loci identified by an updated genome-wide linkage scan: meta-analysis of the Family Blood Pressure Program

BACKGROUND

A preliminary genome-wide linkage analysis of blood pressure in the Family Blood Pressure Program (FBPP) was reported previously. We harnessed the power and ethnic diversity of the final pooled FBPP dataset to identify novel loci for blood pressure thereby enhancing localization of genes containing less common variants with large effects on blood pressure levels and hypertension.

METHODS

We performed one overall and 4 race-specific meta-analyses of genome-wide blood pressure linkage scans using data on 4,226 African-American, 2,154 Asian, 4,229 Caucasian, and 2,435 Mexican-American participants (total N = 13,044). Variance components models were fit to measured (raw) blood pressure levels and two types of antihypertensive medication adjusted blood pressure phenotypes within each of 10 subgroups defined by race and network. A modified Fisher's method was used to combine the P values for each linkage marker across the 10 subgroups.

RESULTS

Five quantitative trait loci (QTLs) were detected on chromosomes 6p22.3, 8q23.1, 20q13.12, 21q21.1, and 21q21.3 based on significant linkage evidence (defined by logarithm of odds (lod) score ≥3) in at least one meta-analysis and lod scores ≥1 in at least 2 subgroups defined by network and race. The chromosome 8q23.1 locus was supported by Asian-, Caucasian-, and Mexican-American-specific meta-analyses.

CONCLUSIONS

The new QTLs reported justify new candidate gene studies. They may help support results from genome-wide association studies (GWAS) that fall in these QTL regions but fail to achieve the genome-wide significance.

Angiogenic growth factors correlate with disease severity in young patients with autosomal dominant polycystic kidney disease

Renal cysts, pain, and hematuria are common presentations of autosomal dominant polycystic kidney disease (ADPKD) in children. Renal function, however, is typically preserved in these patients despite increased renal volume. Since angiogenesis has been implicated in promotion of renal cyst growth in ADPKD, we measured the serum level of various angiogenic factors and early renal structural changes and cardiovascular parameters in 71 patients with ADPKD, with a mean age of 16 years. Renal structure and left ventricular mass index were measured by magnetic resonance imaging or by echocardiogram. Renal function was assessed by creatinine clearance and urinary protein excretion. Serum growth factor levels were measured by enzyme-linked immunosorbent assay. Because of skewed distributions, the various parameters are reported as log(10). Serum log(10) vascular endothelial growth factor was positively correlated with renal and cardiac structure, but negatively with creatinine clearance. Serum angiopoietin 1 levels significantly correlated with structural change in both the kidney and the heart and with urinary protein. Thus, the correlation between angiogenic growth factors with both renal and cardiac disease severity is compatible with a possible role for angiogenesis in the early progression of disease in ADPKD.

A functional variant in the 3'-UTR of angiopoietin-1 might reduce stroke risk by interfering with the binding efficiency of microRNA 211

Angiopoietin-1 is a vascular strengthening factor during vascular development and a protective factor for pathological vascular inflammation and leakage. Brain vascular leaking and inflammation are two important pathological processes of stroke; therefore, we hypothesized that variants of the microRNA-binding site in angiopoietin-1 would affect its expression and confer a risk of stroke. To test our hypothesis, a predicted microRNA-binding site was found in the 3'-UTR of angiopoietin-1 using bioinformatics; variant rs2507800 was identified to be located in the miR-211-binding site of angiopoietin-1. Secondly, the effects of the identified variant on angiopoietin-1 translation were assessed using a luciferase reporter assay and ELISA. We found that the A allele of rs2507800 suppressed angiopoietin-1 translation by facilitating miR-211 binding, but not the T allele. Subjects carrying the TT genotype had higher plasma angiopoietin-1 levels than those with the A allele. Finally, the association of the variant with stroke was tested in 438 stroke patients and 890 controls, and replicated in an independent population of 1791 stroke patients and 1843 controls. The TT genotype resulted in a significant reduction in overall stroke risk {OR, 0.51 [95% confidence interval (CI), 0.36-0.74], P = 0.0003}, ischemic stroke [OR, 0.56 (95% CI, 0.36-0.85), P = 0.007] and hemorrhagic stroke [OR, 0.46 (95% CI, 0.26-0.80), P = 0.007]. These results were confirmed in an independent study. Our results provide evidence that the TT genotype (rs2507800) in the 3'-UTR of angiopoietin-1 might reduce the risk of stroke by interfering with miR-211 binding.

Evaluation of angiopoietins and cell-derived microparticles after stem cell transplantation

Although stem cell transplantation (SCT) is being used for hematopoietic reconstitution following high-dose chemotherapy for malignancy, it involves certain serious transplant-related complications such as graft-versus-host disease (GVHD). Angiopoietins play important roles in angiogenesis. However, the role of angiopoietins after SCT is poorly understood. In this study, 52 patients underwent SCT; 26 patients received allogeneic SCT, while the remaining 26 received autologous SCT. In 48 of 52 patients, levels of angiopoietins, cytokines, and soluble factors were measured by enzyme-linked immunosorbent assay. Soluble Fas ligand (sFasL) and endothelial cell-derived microparticle (EDMP) exhibited significant elevation in the early phase (2-3 weeks) after SCT. In addition, the elevation of interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, and sIL-2 receptor (sIL-2R), which are GVHD markers after allogeneic SCT was observed. The level of angiopoietin (Ang)-2 in allogeneic SCT continued to increase for up to 4 weeks, although the level of Ang-1 did not show significant changes. The patients with high Ang-2 exhibited significant increase of sFasL and EDMP compared with those with low Ang-2. In addition, the patients with high-grade GVHD exhibited a significant increase in Ang-2 compared to patients with low-grade GVHD. In the in vitro experiment using endothelial cells, the suppressive effect of Ang-1 on EDMP generation by TNF-alpha was partially inhibited by the addition of Ang-2. Furthermore, multivariate regression analysis showed that EDMP and sFasL were significant factors in Ang-2 elevation. Our results suggest that Ang-2 generation after allogeneic SCT relates to GVHD.

In vivo platelet activation is responsible for enhanced vascular endothelial growth factor levels in hypertensive patients

BACKGROUND

Essential hypertension may be a consequence of an abnormal regulation of vascular endothelial growth factor (VEGF). In vivo activation of platelets does result in the release of VEGF. Thus, we investigated whether VEGF production in hypertensive patients is related to in vivo platelet activation, and whether it may be modified by aspirin treatment.

METHODS

Plasma VEGF, soluble (s)P-selectin and thrombin-anti-thrombin complex (TATc) were analyzed in 80 patients with therapeutically controlled essential hypertension and 40 age and sex-matched healthy normotensive controls. The effects of a 6-month treatment with aspirin 100 mg/day on VEGF levels of 20 hypertensive patients were also studied.

RESULTS

Plasma VEGF (p<0.0001), sP-selectin (p=0.01) and TATc (p=0.02) levels were higher in hypertensives compared to controls. Multivariate analysis including age, sex, risk factors, cardiovascular disease, anti-hypertensive treatment, sP-selectin and TATc showed that only sP-selectin was an independent predictor of VEGF (beta=0.40, p<0.03). Aspirin treated hypertensives showed a significant reduction of sP-selectin (-26%, p<0.01) and VEGF (-33%, p<0.01) levels. Moreover, the reduction of plasma VEGF levels directly correlated with that of sP-selectin (Rho=0.46, p=0.04).

CONCLUSIONS

In vivo activation of platelets in hypertensive patients is responsible for enhanced circulating VEGF levels, which are significantly lowered by aspirin treatment.

The angiogenic factor thymidine phosphorylase up-regulates the cell adhesion molecule P-selectin in human vascular endothelial cells and is associated with P-selectin expression in breast cancers

Thymidine phosphorylase (TP) is an angiogenic enzyme, catalysing the reversible phosphorylation of thymidine to thymine and 2-deoxyribose. TP is up-regulated in neoplasia, being associated with advanced tumour stage, microvessel density and prognosis in several tumour types. Although TP is a non-mitogenic migratory factor for endothelium, the mechanism by which TP mediates these effects is still unclear. We compared the gene expression profile of endothelial cells grown in vitro in the presence or absence of TP by cDNA microarray analysis. To determine the time-course of TP angiogenic induction, endothelial cells were stimulated with TP (10 ng/ml) for 5 and 18 h. Gene expression levels of Tie2, angiopoietin (Ang)1 and Ang2, measured by RNase protection assay (RPA), showed maximal alteration at 18 h. cDNA from human umbilical vein endothelial cells (HUVEC) grown for 18 h in the presence or absence of TP (10 ng/ml) was hybridized to a human cDNA cytokine array representing 375 angiogenic genes. Significantly altered expression occurred in 89 human angiogenic genes (72 genes were up-regulated and 17 down-regulated). Changes in five genes relevant to vascular remodelling biology (Tie2, nNos, P-selectin, ephrin-B1 and TP) were validated in triplicate experiments by real-time RT-PCR. But only P-selectin gene expression remained significant. Correlation between P-selectin and TP was assessed by immunohistochemistry on 161 human breast cancers, using human tissue microarray. Tumour cell TP correlated with tumour cell P-selectin but not with endothelial cell P-selectin. These data show that TP stimulates changes in mRNA expression maximally after 18 h culture in vitro. It confirms a role for TP in vascular remodelling involving several classes of genes, including the cell adhesion molecule, P-selectin. Although confirmation of the role of TP-mediated cell adhesion molecule (CAM) induction is required; however, this pathway may provide an attractive therapeutic target, since it is likely to affect several important tumour processes, including angiogenesis and metastasis.

Angiopoietin-2 levels are elevated in exudative pleural effusions

OBJECTIVE

To examine the pleural fluid (PF) and serum levels of angiopoietin (Ang)-1, Ang-2, and vascular endothelial growth factor (VEGF) in patients with pleural effusions (PEs).

METHODS

One hundred fifteen patients, 16 with transudative PEs due to heart failure and 99 with exudative PEs (malignant, 40; para-pneumonic, 24; tuberculous, 13; miscellaneous etiologies, 22) were included in the study. PF and serum levels of the growth factors were measured using enzyme-linked immunosorbent assay.

RESULTS

PF Ang-2 and VEGF levels but not Ang-1 levels were higher (p < 0.001) in exudates than in transudates. PF Ang-2 levels were higher in tuberculous PEs than in PEs of any other etiology and were lower in heart failure PEs than in PEs of any other etiology. The highest PF VEGF levels were observed in patients with malignant and parapneumonic PEs. The lowest PF VEGF levels were observed in patients with transudates. In PEs, Ang-2 levels correlate with VEGF levels (p < 0.001), RBC count (p = 0.002), nucleated cell count (p < 0.001), total protein levels (p < 0.001), and lactate dehydrogenase levels (p < 0.001). PF Ang-1 levels were lower than serum Ang-1 levels both in patients with exudates (p < 0.001) and in those with transudates (p = 0.001). PF Ang-2 levels were higher than serum Ang-2 levels both in patients with exudates (p < 0.001) and in those with transudates (p = 0.045). PF VEGF levels were higher than serum VEGF levels in patients with malignant PEs (p < 0.001) and parapneumonic PEs (p = 0.003), but lower than serum VEGF levels in heart failure PEs (p < 0.001). In patients with tuberculous PEs and exudative PEs of miscellaneous etiology, PF and serum VEGF levels did not differ significantly.

CONCLUSION

Ang-2 levels but not Ang-1 levels are elevated in exudative PEs, and they correlate with levels of VEGF and markers of pleural inflammation. It is thus possible that Ang-2 along with VEGF participate in pleural inflammation and the pathogenesis of exudative PEs.

New susceptibility locus for hypertension on chromosome 8q by efficient pedigree-breaking in an Italian isolate

Essential hypertension (EH) affects a large proportion of the adult population in Western countries and is a major risk factor for cardiovascular diseases. EH is a multifactorial disease with a complex genetic component. To tackle the complexity of this genetic component, we have initiated a study of Campora, an isolated village in South Italy. A random sample of 389 adults was genotyped for a very dense microsatellite genome scan and phenotyped for EH. Of this sample, 173 affected individuals were all related through a 2,180-member pedigree and could be integrated within a linkage analysis. The complexity of the pedigree prevented its direct use for a non-parametric linkage (NPL) analysis. Therefore, the method proposed by Falchi et al. [2004, Am. J. Hum. Genet., 75, 1015-1031] was used for automatic pedigree-breaking. We identified a new locus for EH on chromosome 8q22-23 and detected linkage with two known loci for EH: 1q42-43 and 4p16. Simulations showed that the linkage with 8q22-23 is highly genome-wide significant, even when accounting for the breaking of the pedigree. An extension to qualitative traits of another pedigree-breaking approach [Pankratz et al., 2001, Genet. Epidemiol., 21 (Suppl. 1), S258-S263] also detected a significant linkage on 8q22-23 using a remarkably different set of sub-pedigrees and helped to refine the location of the linkage signal. This work both identifies a new locus strongly linked to hypertension and shows that the power of linkage analysis can be improved by the appropriate use of efficient pedigree-breaking strategies.

Functional polymorphisms in the vascular endothelial growth factor gene are associated with development of end-stage renal disease in males

This study elucidates the genetic role of vascular endothelial growth factor (VEGF) as a predisposing factor for progression of chronic kidney disease. Single-nucleotide polymorphisms were genotyped and haplotype structures were determined in the 3' untranslated region (UTR) of VEGF gene, and the distribution of each haplotype in male patients with ESRD (n=101) and healthy male control subjects (n=189) was examined. The 936C/T and 1451C/T polymorphisms in the 3' UTR were in nearly absolute linkage disequilibrium, and haplotype analysis demonstrated that they were the primary responsible single-nucleotide polymorphisms. The distribution of the 936CC-1451CC genotype was significantly more frequent among patients with ESRD than among the age-matched healthy control subjects. In addition to case-control association study, the 936CC-1451CC genotype was also associated with significantly higher plasma VEGF levels in healthy individuals, but a significant association was found only in males, not in females. We also examined the effect of the 936C-1451C haplotype on mRNA stability. Consistent with the results of plasma VEGF levels, mRNA carrying 936C-1451C haplotype showed higher stability. The 936CC-1451CC genotype in the 3' UTR showed not only susceptibility for ESRD but also higher plasma VEGF levels and mRNA stability, indicating the contribution of VEGF to chronic kidney disease progression, especially in males.

Treatment of comorbidities besides the treatment of primary tumor may further increase effective management of cancer

For most of the patients with cancer comorbidity had independent prognostic effect. This negative influence of comorbidity on survival of cancer might be due to several mechanisms: the increased risk of death due to the comorbid condition itself, more contra-indications for anti-cancer treatment, more indications for dose reduction and a higher rate of treatment-related complications, such as infections and cardiovascular events. It is known that in some chronic diseases (e.g., coronary artery disease, hypertension, and obesity) pro-angiogenic growth factors are increased compared to controls and mostly normalized after specific treatment. We propose that increased pro-angiogenic growth factor levels in cancer patients due to comorbidities may lead to the progression of the tumors and poor prognosis. Treatment of comorbidities besides the treatment of primary tumor may further increase effective management of cancer.

Cocoa reduces blood pressure and insulin resistance and improves endothelium-dependent vasodilation in hypertensives

Consumption of flavanol-rich dark chocolate (DC) has been shown to decrease blood pressure (BP) and insulin resistance in healthy subjects, suggesting similar benefits in patients with essential hypertension (EH). Therefore, we tested the effect of DC on 24-hour ambulatory BP, flow-mediated dilation (FMD), and oral glucose tolerance tests (OGTTs) in patients with EH. After a 7-day chocolate-free run-in phase, 20 never-treated, grade I patients with EH (10 males; 43.7+/-7.8 years) were randomized to receive either 100 g per day DC (containing 88 mg flavanols) or 90 g per day flavanol-free white chocolate (WC) in an isocaloric manner for 15 days. After a second 7-day chocolate-free period, patients were crossed over to the other treatment. Noninvasive 24-hour ambulatory BP, FMD, OGTT, serum cholesterol, and markers of vascular inflammation were evaluated at the end of each treatment. The homeostasis model assessment of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), and insulin sensitivity index (ISI) were calculated from OGTT values. Ambulatory BP decreased after DC (24-hour systolic BP -11.9+/-7.7 mm Hg, P<0.0001; 24-hour diastolic BP -8.5+/-5.0 mm Hg, P<0.0001) but not WC. DC but not WC decreased HOMA-IR (P<0.0001), but it improved QUICKI, ISI, and FMD. DC also decreased serum LDL cholesterol (from 3.4+/-0.5 to 3.0+/-0.6 mmol/L; P<0.05). In summary, DC decreased BP and serum LDL cholesterol, improved FMD, and ameliorated insulin sensitivity in hypertensives. These results suggest that, while balancing total calorie intake, flavanols from cocoa products may provide some cardiovascular benefit if included as part of a healthy diet for patients with EH.