Relationship between renal function and circulating microparticles, soluble P-selectin and E-selectin levels in atrial fibrillation.

Atrial fibrillation (AF) and chronic kidney disease are closely related, and any associated risk of stroke and thromboembolism due to AF is increased by concurrent renal dysfunction. The mechanism(s) for this include abnormalities in platelets and endothelial cells. We hypothesized relationships between levels of circulating platelet microparticles (PMPs, defined by CD42b), soluble P selectin (both reflecting platelet activation), soluble E-selectin (reflecting endothelial activation) and endothelial/platelet microparticles (EPMPs, defined by CD31) with progressive renal dysfunction. Blood samples were obtained from 160 anticoagulated AF patients. Microparticles were measured by flow cytometry, soluble E and P selectin levels by ELISA. Renal function was determined by estimated glomerular filtration rate (eGFR). EPMP levels demonstrated a linear increased trend across quartiles of eGFR (p = 0.034) and CKD stage (p < 0.001), and correlated with eGFR and serum creatinine (p < 0.01). PMPs, P-selectin and E-selectin levels were not significantly different across groupings of renal dysfunction, and no significant correlations with eGFR were evident (p = 0.186, p = 0.561, p = 0.746 respectively). Stepwise multivariable regression analysis demonstrated that worsening renal function was an independent predictor of EPMP levels (p < 0.001). In well-anticoagulated AF patients, there is potential relationship between endothelial function (as judged by elevated EPMP levels, with no change in PMPs) and renal function. Other markers of prothombotic state or cellular activation (PMP, P-selectin and E-selectin levels) were not significantly different across the various degree of renal dysfunction. Renal function must be addressed when measuring EPMP levels.

Modelling projections for the uptake of edoxaban in an European population to 2050: effects on stroke, thromboembolism, and health economics perspectives.

AIMS: In the coming decades, the number of Europeans with atrial fibrillation (AF) is set to rise as the population ages, and so with it will the number of strokes. The risk of thromboembolism (principally stroke and systemic embolism) and death can be reduced by the use of the vitamin K antagonists (VKA, e.g. warfarin) and more so by non-VKA oral anticoagulants (NOACs) such as edoxaban. METHODS AND RESULTS: We modelled the effect of the increasing use of edoxaban in preference to warfarin in a European AF population from both clinical and economic perspectives. We estimate that the introduction of NOACs in 2010 eliminated over 88 000 thromboembolisms and deaths annually, of which over 17 000 were ischaemic strokes. At a 1-year cost of €30k per ischaemic stroke, this strategy saved €510 million annually. Should the use of edoxaban increase from 11% in 2013 to 75% by 2030, we expect that rate of thromboembolism and death will fall from 5.67 to 5.42 total events per million patients per year, which will further eliminate over 12 000 of these events annually. At an inflation-adjusted 1-year cost of approximately €35k per ischaemic stroke, this will save €44.5 million each year. At a conservative rate of increase in the AF population of 2.2-fold from 2005, in 2050 there will be around 180 000 AF-related ischaemic strokes that, at an inflation-adjusted cost of around €62k per stroke, sums to €11 116 million. Should the rate of AF rise 2.6-fold from 2005, then in 2050 there will be 214 500 ischaemic strokes that will cost around €13 300 million. CONCLUSION: Our data point to a substantial increase in the human and economic cost burden of AF and so emphasize the need to reduce this burden. This may be achieved by the increased use of oral anticoagulants, particularly with the NOACs such as edoxaban.

Effects of non-vitamin K antagonist oral anticoagulants on fibrin clot and whole blood clot formation, integrity and thrombolysis in patients with atrial fibrillation.

Non-vitamin K antagonist oral anticoagulants (NOACs) are replacing warfarin and heparins in several clinical situations. With varying modes of action, the effects of NOACs on thrombus formation, integrity, and lysis is unknown. To determine whether two techniques of thrombelastography (TEG) and a micro-plate assay (MPA) provide novel data on thrombus formation, integrity and lysis in those taking a NOACs compared to warfarin and a control group taking aspirin. We assessed thrombogenesis, clot integrity and fibrinolysis in blood (TEG) and plasma (MPA) from 182 atrial fibrillation patients-50 on aspirin, 50 on warfarin, and 82 on a NOAC (17 apixaban, 19 dabigatran and 46 rivaroxaban). Eleven of 16 TEG indices and 4 of 5 MPA indices differed (p ≤ 0.01) between those on aspirin, warfarin or a NOAC. Three TEG indices and 4 MPA indices differed (p < 0.01) between the NOACs. Time to initiation of clot formation was most rapid on apixaban, then rivaroxaban and slowest on dabigatran. The rate of clot formation was most rapid on dabigatran, then apixaban, and slowest on rivaroxaban. Clot density was greatest on rivaroxaban, then apixaban, but weakest on dabigatran. The rate of clot dissolution was most rapid in apixaban, then dabigatran, and slowest on rivaroxaban. The TEG and MPA identify major differences in thrombogenesis and fibrinolysis in different NOACs. These techniques may have value in investigating the effects of these drugs on haemostasis in a clinical setting, and in identifying those in need of targeted therapy.

Plasma CX3CL1 levels and long term outcomes of patients with atrial fibrillation: the West Birmingham Atrial Fibrillation Project.

BACKGROUND: There is growing evidence that chemokines are potentially important mediators of the pathogenesis of atherosclerotic disease. Major atherothrombotic complications, such as stroke and myocardial infarction, are common among atrial fibrillation (AF) patients. This increase in risk of adverse events may be predicted by a score based on the presence of certain clinical features of chronic heart failure, hypertension, age 75 years or greater, diabetes and stroke (the CHADS2 score). Our objective was to assess the prognostic value of plasma chemokines CCL2, CXCL4 and CX3CL1, and their relationship with the CHADS2 score, in AF patients. METHODS: Plasma CCL2, CXCL4 and CX3CL1 were measured in 441 patients (59% male, mean age 75 years, 12% paroxysmal, 99% on warfarin) with AF. Baseline clinical and demographic factors were used to define each subject's CHADS2 score. Patients were followed up for a mean 2.1 years, and major adverse cardiovascular and cerebrovascular events (MACCE) were sought, being the combination of cardiovascular death, acute coronary events, stroke and systemic embolism. RESULTS: Fifty-five of the AF patients suffered a MACCE (6% per year). Those in the lowest CX3CL1 quartile (≤ 0.24 ng/ml) had fewest MACCE (p = 0.02). In the Cox regression analysis, CX3CL1 levels >0.24 ng/ml (Hazard ratio 2.8, 95% CI 1.02-8.2, p = 0.045) and age (p = 0.042) were independently linked with adverse outcomes. The CX3CL1 levels rose directly with the CHADS2 risk score (p = 0.009). The addition of CX3CL1 did not significantly increased the discriminatory ability of the CHADS2 clinical factor-based risk stratification (c-index 0.60 for CHADS2 alone versus 0.67 for CHADS2 plus CX3CL1 >0.24 ng/ml, p = 0.1). Aspirin use was associated with lower levels of CX3CL1 (p = 0.0002) and diabetes with higher levels (p = 0.031). There was no association between CXCL4 and CCL2 plasma levels and outcomes. CONCLUSION: There is an independent association between low plasma CX3CL1 levels and low risk of major cardiovascular events in AF patients, as well as a linear association between CX3CL1 plasma levels and CHADS2-defined cardiovascular risk. The potential for CX3CL1 in refining risk stratification in AF patients merits consideration.

Vascular and platelet responses to aspirin in patients with coronary artery disease.

BACKGROUND: Variability in the response to aspirin (sometimes known as aspirin resistance) in modulating platelet activity is a potentially important clinical issue in coronary artery disease (CAD), but may be also be important in other areas of pathophysiology. MATERIALS AND METHODS: Testing the hypothesis of a relationship between aspirin resistance and vascular function, inflammation and coagulation, we recruited 175 stable CAD outpatients taking 75 mg aspirin daily. Indices were compared to 58 controls not taking aspirin. Platelet activity was assessed by light transmission aggregometry (LTA) to 0·5 mg/mL arachidonic acid (AA), plasma markers soluble P selectin and thromboxane (ELISA), and resting and AA stimulated membrane P selectin and PAC-1 expression (flow cytometry). Vascular function was assessed by arterial stiffness (Sphygmocor system), von Willebrand factor and soluble E selectin (ELISA), inflammation by high sensitivity CRP and interleukin-6, and coagulation by tissue factor and fibrin d-dimers levels (all immunoassay). RESULTS: The 5-min LTA response AA was superior to flow cytometry in discriminating the response of platelets to aspirin. Using the cut-off of 20% LTA response to AA, 32·6% of patients were aspirin resistant. The latter had higher soluble P selectin (P = 0·03), CRP (P = 0·029) and fibrin d-dimers (P = 0·01) compared to those who were aspirin sensitive. There was no relationship between aspirin response status and any vascular index. CONCLUSION: We conclude that LTA is a more sensitive marker of aspirin resistance than is flow cytometry for P-selectin and PCA-1, and that aspirin response has no influence on vascular function.

Angiogenin outperforms VEGF, EPCs and CECs in predicting Dukes' and AJCC stage in colorectal cancer.

BACKGROUND: Circulating endothelial cells (CECs), endothelial progenitor cells (EPCs), Willebrand factor (vWf), soluble E-selectin, vascular endothelial growth factor (VEGF) and angiogenin are of interest in cancer vascular biology. However, few studies have looked at more than one in combination. We set out to determine which would be best in predicting the Dukes' and American Joint Committee on Cancer (AJCC) scores in colorectal cancer patients. METHODS: We recruited 154 patients with colorectal cancer, 29 healthy controls and 26 patients with benign bowel disease. CD34(+) /CD45(-) /CD146(+) CECs and CD34(+) /CD45(-) /CD309[KDR](+) EPCs were measured by flow cytometry, plasma markers by ELISA. RESULTS: All research indices were raised in colorectal cancer (P < 0·05) compared to control groups. Although CECs (P < 0·05), EPCs (P < 0·01) and angiogenin (P < 0·01) increased stepwise across the four Dukes' stages and four AJCC stages, only angiogenin remained significant in multiple regression analysis (P = 0·003 for Dukes, P = 0·01 for AJCC). Angiogenin levels were higher in Dukes' stages C and D compared to stage A, and AJCC stages 4-6 and 7-10 compared to stage 1 (all P < 0·05). Adding a second research marker to angiogenin did not markedly improve this relationship. CONCLUSION: Although we found disturbances in endotheliod cells and plasma markers of the endothelium and growth factors, only angiogenin levels were independently associated with progression of the Dukes' stage and AJCC stage, with the association with Duke's stage being stronger. We suggest that angiogenin is a potential biomarker in risk stratification for colorectal cancer, and may aid clinical decision making.

An observational study of endothelial function in early arthritis.

BACKGROUND: Endothelial dysfunction is present in established rheumatoid arthritis, but it is not clear at what stage of the disease this abnormality develops. We set out to determine whether endothelial damage/dysfunction is present in a group of patients with early arthritis (EA) (new onset inflammatory arthritis, EA). MATERIALS AND METHODS: Eighteen patients with EA, 48 healthy controls and 25 disease controls were recruited. Plasma was obtained for endothelial [von Willebrand factor (vWF) and soluble E-selectin] and angiogenesis markers (vascular endothelial growth factor and its receptor sFlt-1), adhesion molecules (intercellular adhesion molecule 1 and vascular cell adhesion molecule 1) and circulating endothelial cells (CECs, as a marker of endothelial damage). Microvascular endothelial function was assessed using laser Doppler perfusion imaging and macrovascular function using flow-mediated dilatation of the brachial artery. RESULTS: von Willebrand factor and CECs (both P < 0.05) were significantly elevated in EA suggesting endothelial dysfunction and damage but were unrelated to classical laboratory markers of inflammation C-reactive protein, erythrocyte sedimentation rate or IL6. No other biomarkers was elevated in EA. Microvascular and macrovascular abnormalities were confined to endothelium-independent (smooth muscle cell) responses. CONCLUSIONS: Endothelial damage/dysfunction is present early in the course of inflammatory arthritis but is not directly related to inflammation markers.

Endothelial progenitor cells and circulating endothelial cells in early prostate cancer: a comparison with plasma vascular markers.

BACKGROUND: Separate studies indicate that endothelial perturbation, as demonstrated by abnormal endothelial progenitor cells (EPCs), circulating endothelial cells (CECs), and plasma markers such as von Willebrand factor (vWf) and soluble E selectin (sEsel) are present in cancer. However, there are no reports where these indices are compared. Accordingly, we hypothesized altered EPCs and CECs in prostate cancer that would correlate with vWf, sEsel, and prostate specific antigen (PSA). METHODS: We recruited 29 men with biopsy proven prostate cancer, with 25 with benign prostate disease and 27 free of prostate disease. CECs were defined on flow cytometry as being CD34+, CD146+, CD45-, and CD309-, EPCs were similarly defined as being CD34+, CD309+,CD45-, and CD146-. vWf, sEsel, and PSA were measured by immunoassay. RESULTS: Despite higher PSA, sE-sel, and vWf in prostate cancer (all P < 0.02), neither EPCs, CECs, nor their ratio, were significantly different. EPCs and CECs correlated significantly with each other in each group (r > 0.48, P < 0.01) but failed to correlate with any plasma marker. CONCLUSION: Unlike plasma endothelial markers, CECs and EPCs may play little part in the pathophysiology of early prostate cancer.

Endothelium-dependent and endothelium-independent vasodilatation of the cutaneous circulation in sickle cell disease.

BACKGROUND: Whilst there is evidence of endothelial dysfunction in sickle cell disease (SCD), whether this affects regulation in the microcirculation is not known. METHODS: We studied 19 patients with SCD, eight with sickle cell-haemoglobin C (HbSC), 11 with homozygous sickle cell (HbSS) disease and 11 matched control subjects with normal haemoglobin genotype (HbAA). Vasodilator responses were evoked by iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) in finger and forearm, cutaneous red cell flux (RCF) being measured by laser Doppler fluximetry. RESULTS: Increases in RCF evoked in the finger by ACh were not different between SCD and HbAA subjects (P = 0·789), but were smaller in patients with HbSS than HbSC (P < 0·05). By contrast, increases in RCF evoked in forearm by ACh were greater in SCD than HbAA subjects (P < 0·05) and similar in patients with HbSC and HbSS. Increases in RCF evoked by SNP did not differ between patients with SCD and HbAA subjects in finger or forearm. CONCLUSIONS: Our results indicate that endothelium-dependent cutaneous vasodilatation is augmented in forearm of patients with SCD relative to HbAA subjects, but impaired in the finger of SCD patients with the more severe HbSS genotype. Thus, endothelial dysfunction associated with SCD is not accompanied by generalised impairment in endothelium-dependent dilatation, but with more localised impairment that includes the fingers of patients with HbSS.

Validation of the Edinburgh Claudication Questionnaire in 1st generation Black African-Caribbean and South Asian UK migrants: a sub-study to the Ethnic-Echocardiographic Heart of England Screening (E-ECHOES) study.

BACKGROUND: We determined the diagnostic accuracy of the Edinburgh Claudication Questionnaire (ECQ) in 1st generation Black African-Caribbean UK migrants as previous diagnostic questionnaires have been found to be less accurate in this population. We also determined the diagnostic accuracy of translated versions of the ECQ in 1st generation South Asian UK migrants, as this has not been investigated before. METHODS: Subjects were recruited from the Ethnic-Echocardiographic Heart of England Screening (E-ECHOES) study, a community based screening survey for heart failure in minority ethnic groups. Translated versions of the ECQ were prepared following a recognised protocol. All participants attending screening between October 2007 and February 2009 were asked to complete the ECQ in the language of their choice (English, Punjabi, Bengali, Urdu, Hindi or Gujarati). Subjects answering positively to experiencing leg pain or discomfort on walking were asked to return to have Ankle Brachial Pressure Index (ABPI) measured. RESULTS: 154 out of 2831 subjects participating in E-ECHOES (5.4%) were eligible to participate in this sub-study, for which 74.3% returned for ABPI assessment. Non-responders were younger than participants (59[9] vs. 65[11] years; p=0.015). Punjabi, English and Bengali questionnaires identified participants with Intermittent Claudication, so these questionnaires were assessed. The sensitivities (SN), specificities (SP), positive (PPV) and negative (NPV) predictive values were calculated. English: SN: 50%; SP: 68%; PPV: 43%; NPV: 74%. Punjabi: SN: 50%; SP: 87%; PPV: 43%; NPV: 90%. Bengali: SN: 33%; SP: 50%; PPV: 13%; NPV: 73%. There were significant differences in diagnostic accuracy between the 3 versions (Punjabi: 83.8%; Bengali: 45%; English: 62.2%; p<0.0001). No significant differences were found in sensitivity and specificity between illiterate and literate participants in any of the questionnaires and there was no significant different difference between those under and over 60 years of age. CONCLUSIONS: Our findings suggest that the ECQ is not as sensitive or specific a diagnostic tool in 1st generation Black African-Caribbean and South Asian UK migrants than in the Edinburgh Artery Study, reflecting the findings of other diagnostic questionnaires in these minority ethnic groups. However this study is limited by sample size so conclusions should be interpreted with caution.

Inflammatory cytokines, endothelial markers and adhesion molecules in rheumatoid arthritis: effect of intensive anti-inflammatory treatment.

Tumour necrosis factor alpha (TNF-alpha) and interlekin-6 (IL-6) are key inflammatory cytokines in the pathogenesis of rheumatoid arthritis (RA), a disease also associated with endothelial perturbation and increased serum levels of adhesion molecules. As relationships between these processes and molecules are unclear, we tested the hypotheses (a) that TNF-alpha and IL-6 are linked to endothelial activation/damage and levels of soluble adhesion molecules, and (b) that intensive anti-inflammatory treatment improves levels of these indices. We recruited 66 patients with RA, 48 community controls (CC), and 25 disease controls (DC). Plasma TNF-alpha and IL-6 were compared to markers of vascular biology (vWF, sE-sel), soluble adhesion molecules (sICAM, sVCAM) and routine inflammatory markers (CRP and ESR). Blood was obtained at baseline and at 1 week and again 4 weeks after anti-inflammatory treatment in a subgroup of 29 patients with RA. With the exception of sE-selectin, RA patients had increased levels of all plasma markers compared to the HCs, whilst levels in the DCs were largely intermediate between RA and the CCs. Within the RA group, sEsel correlated with both CRP and ESR whilst TNF-alpha correlated with sVCAM (all r > 0.32, P < 0.01). After 1 week of combined anti-inflammatory therapy, only CRP, ESR, sEsel and sVCAM were significantly reduced (all P < 0.05). In RA, endothelial activation (as sEsel) correlates with classical markers of inflammation and is reduced by intensive anti-inflammatory medications.

Circulating endothelial cells and rheumatoid arthritis: relationship with plasma markers of endothelial damage/dysfunction.

OBJECTIVES: RA is associated with endothelial cell dysfunction (ECD) and increased cardiovascular mortality and morbidity. Circulating endothelial cells (CECs) are a novel marker of severe endothelial damage. We hypothesized altered CECs in patients with RA compared with community controls (CCs) and hospital controls (HCs, with diabetes and hypertension) correlate with established plasma markers of inflammation and of ECD. METHODS: CECs (CD146-immunobeads), von Willebrand factor, soluble E-selectin, soluble intercellular adhesion molecule-1, soluble vascular endothelial adhesion molecule-1 (sVCAM, all ELISA) and C-reactive protein (CRP, immunonephelometry) were measured in 57 patients with RA, 45 CC and 23 HC patients. RESULTS: CECs in RA [median/interquartile range 8 (5-13.5) cells/ml] were elevated compared with either CC [4 (2-8.5) cells/ml] or HC [4 (1-8) cells/ml] (both P < 0.001). Levels of CECs did not correlate with other markers of ECD or of inflammation but did correlate inversely with sVCAM. CONCLUSION: Evidence of endothelial damage in the form of mildly increased numbers of CECs is present in RA and is independent of plasma markers of inflammation and of ECD.

Markers of thrombosis and hemostasis in acute coronary syndromes: relationship to increased heart rate and reduced heart-rate variability.

BACKGROUND: Acute coronary syndromes (ACS) are characterized by abnormal heart-rate variability (HRV) and biomarkers of endothelial damage and thrombosis. HYPOTHESIS: We hypothesized an association between these factors in patients with ACS. METHODS: We studied 99 patients with ACS measuring HRV and plasma markers of endothelial damage/dysfunction (von Willebrand factor, vWF) and thrombosis/hemostasis (soluble P-selectin (s-Psel); CD(40)-ligand (CD(40)-L); D-dimer). HRV and plasma indices were compared to age- and gender-matched controls. Measures were repeated at 4 months in a subset. vWF, s-Psel and D-Dimer levels were raised compared to control. RESULTS: HRV indices were reduced (mean RR, SDNN, SDNNi, RMSSD, Triangular index, LF and HF). There were weak correlations between mean RR and s-Psel (R = - 0.234, p = 0.023) and D-dimer (R = - 0.219, p = 0.041). At 4-month follow-up, significant correlations were between mean RR and CD(40)L (R = - 0.414, p = 0.008) and D-dimer (R = - 0.363, p = 0.012). On multivariate logistic regression analysis statin use (p = 0.046) was the only independent predictor of acute s-Psel levels. Age (p = 0.004) and mean RR interval (p = 0.01) were independent predictors of D-dimer levels at follow-up. CONCLUSIONS: Abnormal HRV is associated with markers of hemostasis and thrombosis in ACS, and present both in the acute and rehabilitation phases.

Von Willebrand factor antigen levels predict major adverse cardiovascular events in patients with carotid stenosis of the ICARAS study.

BACKGROUND AND AIMS: Von Willebrand factor (VWF) plays an important role in thrombogenesis and mediates platelet adhesion particularly under high shear stress. Such conditions are generally found in stenotic arteries and can eventually cause myocardial infarction or stroke. We aimed to study whether levels of VWF antigen (VWF:Ag) predict future major adverse cardiovascular events (MACE) in patients suffering from carotid artery stenosis. METHODS: Patients with atherosclerotic carotid artery disease defined by the presence of nonstenotic plaques or any degree of carotid stenosis were prospectively enrolled. Concentrations of VWF were measured by enzyme immunoassay. RESULTS: VWF:Ag levels were more stable after 4 freeze-thaw cycles, when compared to VWF activity, and we showed similar concentrations of VWF in citrated plasma and serum (±4%). Levels of VWF:Ag predicted future cardiovascular events in 811 patients with carotid stenosis independent of known cardiovascular risk factors. Patients with VWF:Ag concentrations in the 4th quartile had a 44% event rate after an average 3-year follow up and a hazard ratio of 2.15 (95% confidence interval 1.46-3.16; p < 0.001). CONCLUSIONS: High concentrations of VWF:Ag predict major cardiovascular events in patients with carotid stenosis, and given their high event rate may be useful for risk stratification of such patients.

Platelets: the universal killer?

For many, the final terminal event in life is cessation of the heart beat. In turn, this is generally because this organ has been deprived of oxygen and glucose as the blood can no longer deliver these requirements to the myocardium. The principal reason for this is blockage of one or more coronary arteries or arterioles by platelet rich thrombus. A similar process exists for the pathophysiology of stroke--a disabilitating and often fatal event caused by occlusion or rupture of arteries in, or feeding, the brain. These scenarios are best developed in cardiovascular disease, but apply to almost all human disease. Therefore, the ultimate culprit for these major life events is the overactive platelet-too ready to form an inappropriate thrombus. Thus, one way forward in postponing an occlusive thrombotic event is to minimise platelet activation, new tools and treatments for which are eagerly sought.

Changes in plasma vascular endothelial growth factor, angiopoietins, and their receptors following surgery for breast cancer.

BACKGROUND: Vascular endothelial growth factor (VEGF), a major angiogenic growth factor, is involved in the pathogenesis of cancer. Plasma VEGF is raised in breast cancer and falls after successful surgery. Less is known about angiopoietins 1 and 2 (Ang-1, Ang-2). All three growth factors act on cells via receptors; Flt-1 for VEGF and Tie-2 for the angiopoietins. Cancer is also marked by abnormalities in platelet activation (marked by soluble P selectin) and inflammation (interleukin-6 [IL6]). We hypothesised altered plasma Ang-1, Ang-2, Flt-1 and Tie-2 in breast cancer that would normalize after 3 and 12 months treatment (i.e., surgery plus chemo/radiotherapy). METHODS: Baseline venous blood was obtained from 40 women with breast cancer and 30 age-matched women with benign breast disease (BBD) also requiring surgery. Samples were taken again 3 months and 1 year later. Soluble P selectin, IL6, VEGF, Ang-1, Ang-2, Flt-1 and Tie-2 were measured in citrated plasma by ELISA. RESULTS: Women with breast cancer had raised VEGF (7-fold), Ang-1 (50% higher) and Tie-2 (2-fold), but lower Flt-1 (to 26%), compared to the BBD women that broadly correlated with markers of platelet activation and inflammation. A level of Tie-2 or VEGF >95th percentile of the BBD group correctly identified 68% and 52% of the women with breast cancer. After 3 months of treatment, VEGF and Ang-1 normalized (as did IL6 and soluble P selectin) but Tie-2 was significantly lower only after 1 year. There were no significant changes in the women with BBD. CONCLUSIONS: Treatment for breast cancer (surgery followed by chemotherapy and/or radiotherapy) is effective in reducing plasma VEGF, Tie-2 and Ang-1. These may be linked pathogenically with coagulation and inflammation.

Significant decrease in angiopoietin-1 and angiopoietin-2 after radical prostatectomy in prostate cancer patients.

BACKGROUND: Abnormalities in coagulation/platelet activation and angiogenesis are present in all common human cancers. We hypothesized that surgical treatment of prostate cancer would modulate these abnormalities. METHODS: Forty-two men with biopsy-proven prostate cancer were recruited of whom 24 had radical prostatectomy (RP), 12 other treatments and 6 had no treatment. RP patients were followed up from baseline, and samples were collected at 3- and 12-month intervals to assess the effects of the surgery. Plasma was obtained for the measurement of markers of vascular/coagulation/platelet activation (von Willebrand factor (vWf), soluble P selectin (sPsel) (all ELISA), fibrinogen and D-dimer (both nephelometry)) and angiogenesis (vascular endothelial growth factor (VEGF), angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2) and their receptors s-Flt-1 and s-Tie-2). We also measured the angiogenesis markers VEGF and angiopoietin-1 within platelets (all ELISA). RESULTS: In those undergoing RP, there were changes in plasma VEGF (to 48% of pre-surgery levels at 1 year follow up), Ang-1 (to 82%), Ang-2 (to 27%), sPsel (78%), and fibrinogen (to 91%) at 3 months and/or 12 months (p<0.03). The relative falls in Ang-2, Ang-1 and VEGF were not significant (p=0.448). CONCLUSIONS: RP is associated with a lowering of markers of angiogenesis and platelet activation. This suggests that these pathological processes are driven to a large extent by the tumour and/or tumour-secreted factors, and that removal of the primary growth results in a gradual normalisation of measured indices.

Elevated platelet microparticle levels in nonvalvular atrial fibrillation: relationship to p-selectin and antithrombotic therapy.

BACKGROUND: Platelet microparticles (PMPs), are procoagulant membrane vesicles that are derived from activated platelets, the levels of which are elevated in patients with hypertension, coronary artery disease (CAD), diabetes, and stroke, all of which are conditions that lead to (and are associated with) atrial fibrillation (AF). We hypothesized the following: (1) PMP levels are elevated in patients with AF compared to levels in both healthy control subjects (ie, patients without cardiovascular diseases who are in sinus rhythm) and disease control subjects (ie, patients with hypertension, CAD, diabetes or stroke, but who are in sinus rhythm); (2) PMP levels correlate with levels of soluble P-selectin (sP-selectin) [a marker of platelet activation]; and (3) PMP levels are related to the underlying factors in patients with AF that contribute to the overall risk of stroke secondary to AF. METHODS: We performed a case-control study of 70 AF patients, 46 disease control subjects and 33 healthy control subjects. Peripheral venous levels of PMP and sP-selectin were analyzed by flow cytometry and enzyme-linked immunosorbent assay, respectively. RESULTS: Both AF patients and disease control subjects had significantly higher levels of PMPs (p < 0.001) and sP-selectin (p = 0.001) compared to healthy control subjects, but there was no difference between AF patients and disease control subjects. There was no difference in PMP levels between patients with paroxysmal and permanent AF (p = 0.581), and between those receiving therapy with aspirin and warfarin (p = 0.779). No significant correlation was observed between PMP and sP-selectin levels (p = 0.463), and the clinical characteristics that contribute to increased stroke risk in patients with AF. On stepwise multiple regression analysis in the combined cohort of AF patients plus disease control subjects, the presence/absence of AF was not an independent determinant of PMP and sP-selectin levels. CONCLUSION: There is evidence of platelet activation (ie, high PMP and sP-selectin levels) in AF patients, but this is likely to be due to underlying cardiovascular diseases rather than the arrhythmia per se.

Effects of percutaneous coronary intervention on peripheral venous blood circulating endothelial cells and plasma indices of endothelial damage/dysfunction.

BACKGROUND: The relationship between endothelial damage/dysfunction and coronary artery disease is well recognized. However, the effects of percutaneous coronary intervention (PCI) [stenting/angioplasty] on circulating markers of endothelial damage/dysfunction (eg, von Willebrand factor [vWF], soluble E-selectin [sEsel] levels, and more recently circulating endothelial cells [CECs]) has been less well defined. AIMS AND METHODS: We investigated the effects of both diagnostic coronary angiography (CA) [n = 15; blood sampling immediately before CA and 15 min after CA] and PCI (n = 38; blood sampling before PCI, 15 min after PCI, and 24 h after PCI) on levels of CECs, vWF, and sEsel across comparable patient groups. We also included a cohort of comparable healthy control subjects in order to compare baseline levels of three endothelial markers. RESULTS: There were no differences in baseline levels of CECs, vWF, or sEsel between the three study groups (healthy control subjects, CA, PCI; all p = not significant). Following CA (before to 15 min after), there were no significant changes in vWF and CECs (p = not significant). Following PCI, there were significant increases observed at 15 min after PCI and at 24 h after PCI (when compared with pre-PCI levels) in CECs (p = 0.0006), vWF (p = 0.007), and sEsel (p = 0.024). CONCLUSION: We observed significant increases in three endothelial markers (CECs, vWF, and sEsel) with elective PCI but not CA. This is in keeping with endothelial damage/dysfunction following PCI.