MO765: Should We have to Create A Proximal Fistula in First Instance for Patients ≥75 Years Old?

BACKGROUND

In France, the Network Epidemiology and Information in Nephrology evaluated the incidence of cases of chronic end-stage renal disease (ESRD), treated by dialysis, of patients aged ≥75 years at 39.8% (2015).

Timely placement and development of functional fistulas for haemodialysis remain difficult logistical problems along with their high failure rate. Cardiovascular (CV) morbidity-mortality increases when patients initiate catheter-based treatment. The recommendations call for a glomerular filtration rate (GFR) between 15 and 30 mL/min/1.73m² (EBPG 2007 and Canadian 2006) to implement a fistula. The older the patients, the more the quality of the venous network deteriorates. In this population, clinicians face a simple problem: creating a too early fistula and preparing patients for an adequate supply.

The surgery of vascular approaches tries to avoid two pitfalls: ‘too much to preserve’ the vascular capital, ‘too much to privilege’ the permeability of the first by creating proximal approaches (Barrou B.). The guidelines [Kidney Disease Outcomes Quality Initiative (K/DOQI) 2006] recommend the most distal vascular approach possible.

Since 2016, CKD patients aged ≥75 years, have been implanted with arteriovenous fistula (native or prosthetic), localized in the first line of the humero-cephalic vein, huméro-basilique, or humero-axillary. Our primary objective is to assess primary permeability in a population of patients aged ≥75 years with stage IV/V chronic kidney disease (CKD) after the first-line proximal fistula.

METHOD

All patients aged ≥75 years for which a first-line proximal VA was created between 1 January 2016 and 31 December 2019 have been retrospectively reviewed in an observational study. They were followed for 12 months. A quarterly compilation of data has been produced.

RESULTS

A total of 31 patients (74% of men) benefit from the creation of a native fistula (90.3%) or prosthetic. During follow-up, 8 patients were excluded. 29% of patients had started catheter haemodialysis treatment prior to the creation of their first fistula.

A total of 7 changed fistula from initial surgery during the study, of which 2 after the first use. At the creation of the vascular access, the median age of patients is 81 years, of which 35.5% have vascular nephropathy and 19.4% have diabetic nephropathy.

The location of the anastomosis is as follows: 84% FAV brachiocephalic, 10% FAV brachiobasilic and 6% FAV axillary. At 12 months, 16 patients were still under observation.

A total of 5 patients had thrombosis of their VA (80% of native fistulas). The average interval between the creation of the first, and the thrombosis is 2.18 months. Patients dialyzed with VA were 68%. On a scale from 0 (no difficulty) to 10 (puncture not performed), the average difficulty score of the first puncture is 2.2.

The average time in the day between the first puncture and first ‘effective’ dialysis on the first 13.9 days and the average weekly duration of dialysis at the first effective puncture is 11.29 hours. There are 28 hospitalizations, 21% of which are related to VA, 37 ultrasound, 9 angiography and 4 surgical repairs were performed on VA. Only one ischaemia of the hand is observed, treated medically.

Estimates of the risk of thrombosis associated with diabetes are confirmed [P = 0.02; 95% confidence interval (95%CI); hazard ratio (HR): 0.054–0.332]. At 12 months, 94% of the surroundings are permeable without any thrombosis.

CONCLUSION

This study confirms the interest in a proximal vascular approach in people aged ≥75. We have voluntarily included patients from the creation of their VA and for the majority before the time of starting haemodialysis. The average age is high in a high-risk epidemiological context (HTA, diabetes) and the number of early deaths (16%).

The quality of the surroundings is confirmed by the percentage of native fistula at nearly 90% in accordance with the guidelines. The surgical team is motivated and sensitized in this collaborative project. A total of 52% of patients remained in observation at M12 and 94% had a permeable first with satisfactory dialysis quality.

These results are encouraging and require a broader multicentre prospective and comparative study like other problems in managing vascular access for haemodialysis.

What Total Body Water Measurement Should Be Used for Prescribing the Dialysis Dose in Low-Flow Home Daily Dialysis?

INTRODUCTION

In low-flow home daily dialysis (HDD), the dialysis dose is evaluated from the total body water (TBW). TBW can be estimated by anthropometric methods or bioimpedance spectroscopy.

METHODS

A multicentric cross-sectional study of patients in HDD for >3 months was conducted to assess the correlation and the difference between the anthropometric estimate of TBW (Watson-TBW) and the bioimpedance estimate (BIS-TBW) and to analyse the impact on the dialysate volume prescribed.

RESULTS

Forty patients from 10 centres were included. The median BIS-TBW and Watson-TBW were 35.1 (29.1-41.4 L) and 36.9 (32-42.4 L), respectively. The 2 methods had a good correlation (r = 0.87, p < 0.05). However, Bland-Altman analysis showed an overestimation of TBW with Watson's formula, with a bias of 2.77 L. For 4, 5, or 6 sessions per week, the use of Watson-TBW increases the dialysate prescription per week by 100 L, 45 L, or 10 L, respectively, over our entire cohort. There is no increase in the volume of dialysate prescribed with the 7 sessions per week schedule.

CONCLUSION

BIS-TBW and Watson-TBW estimation have a good correlation; however, Watson's equation overestimates TBW. This overestimation is negligible for a prescription frequency of >5 sessions per week.

Concomitant Secretion by A431 Cells of Tissue Plasminogen Activator and a Specific Inhibitor Masks EGF Modulation of tPA Activity

It has previously been reported that EGF enhances uPA but not tPA in the A431 squamous carcinoma cell line. To determine whether the absence of tPA modulation by EGF reflected steady levels or the action of an anti-activator, we assayed tPA, PAI-1 and tPA/PAI-1 complexes by zymography and immunological assays. Under conditions in which EGF had no effect on tPA activity, tPA antigen paradoxically increased with a concomitant rise of tPA/PAI-1 complexes. This indicated that tPA was rapidly inactivated through the formation of a complex, immunologically and electrophoretically related to tPA/PAI-1. tPA antigen and tPA/PAI-1 complexes were modulated by EGF in a time and concentration dependent manner. PAI-1 antigen was secreted into A431 medium (CM) after a lag phase of 16 h in both control andEGF-treated cultures. Evidence is presented here that two forms ofPAI-1 are present in A431 CM: an inactive form and an active form which neutralizes the tPA secreted, masking its enhancement by EGF infunctional assays.

Evaluation of Sensitivity and Specificity of a Standardized Procedure Using Different Reagents for the Detection of Lupus Anticoagulants

This study was designed to test the sensitivity and specificity of a combination of 3 phospholipid-dependent assays performed with various reagents, for the detection of lupus anticoagulant (LA). Plasmas containing an LA (n = 56) or displaying various confounding pathologies [58 intrinsic pathway factor deficiencies, 9 factor VIII inhibitors, 28 plasmas from patients treated with an oral anticoagulant (OAC)] were selected. In a first step, the efficiency of each assay and reagent was assessed using the Receiving Operating Characteristic (ROC) method. Optimal cut-offs providing both sensitivity and specificity ≥80% were determined. The APTT assay and most of the phospholipid neutralization assays failed to discriminate factor VIII inhibitors from LA. In a second step, using the optimal cut-offs determined above, the results of all the possible combinations of the 3 assays performed with 4 different reagents were analyzed. Thirteen combinations of reagents allowed ≥ 80% of plasmas of each category (LA, factor deficiency or OAC) to be correctly classified (3/3 positive test results in LA-containing plasmas and 0/3 positive results in LA-negative samples).

French Multicentric Evaluation of Recombinant Tissue Factor (Recombiplastin) for Determination of Prothrombin Time

Recombiplastin, a recombinant a human tissue factor, elaborated by Ortho Diagnostic Systems, produced by Baculovirus and relipidated with highly purified phospholipids, was tested as a new reagent for determining prothrombin time (PT) in a French multicentric study. Its intralaboratory- performances, including sensitivity, repeatability, reproducibility and stability, were explored to establish whether its use would reduce the interlaboratory dispersion of PT values, and therefore improve the standardization of oral anticoagulant treatment.

The 9 university hospital hematology laboratories involved in this study used the same type of instrument (KC 10). For 10 consecutive days, they determined PTS on a normal plasma pool, plasma dilutions of 1/2, 1/3 and 1/8, 3 identical lyophilized calibrated plasmas, as well as plasmas from 20 normal subjects, 50 patients on oral anticoagulant therapy with Recombiplastin which has an International Sensitivity Index (ISI) of 1, and 2 commercial thromboplastin extracts (ISI #1 or 2). In the patients on anticoagulants, factors VII, X and V were measured when results were conflicting.

The intra and interlaboratory reproducibilities of Recombiplastin, calculated on the basis of either PTS expressed in seconds, or of the International Normalized Ratio (INR), were good, with coefficients of variation (CV) similar to those observed with the 5 other reagents used by the different laboratories (2% <CV <8%).

The stability of Recombiplastin was excellent, with no variation in PT after 72 h of incubation at 37° C.

A normal PT of 12 s was obtained with Recombiplastin, similar to the values found for the reagents with ISI #2. In the patients on anticoagulants, Recombiplastin gave the longest coagulation times (PTRecombipiastin = 64.2 s vs PTNeoPlastin = 32.8 s, and PTThromborel = 54.4 s). These results suggest that Recombiplastin is highly sensitive to the changes in coagulation induced by anticoagulants. Recombiplastin was more sensitive to factor VII deficiency than any of the other reagents, even those with ISI #1.

The coefficients of correlation between the INRS calculated on the basis of the PTS obtained with Recombiplastin and the INRS based on the PTS for other thromboplastins, were satisfactory (0.85 <R <0.95) but a breakpoint in the slope of the regression curves was observed when INR >4. This observation requires further investigation, particularly in connection with the exact ISI values for Recombiplastin and the other thromboplastins used in this study.

In conclusion, Recombiplastin is stable and sensitive and gives accurate reproducible results. However, the behavior of Recombiplastin is slightly different from that of the commercial reagents whether their ISI is 1 or 2, and its use did not reduce the interlaboratory dispersion of PT values.

Rapid Isolation of Human Endothelial Cells from Whole Blood Using S-Endo1 Monoclonal Antibody Coupled to Immuno-Magnetic Beads: Demonstration of Endothelial Injury after Angioplasty

The presence in whole blood of circulating endothelial cells (EC) has been a subject of debate for many years. It could represent a good marker of vessel injury. We demonstrate here that human endothelial cells can be directly isolated and identified in circulating blood by means of an endothelial cell specific monoclonal antibody, S-Endol, coupled to micromagnetic beads. The specificity and efficacy of the assay were established using normal blood samples with cultured EC added. Specific rosettes formed between EC and beads could subsequently be isolated with a magnet. The rosetted cells were recovered with a yield >80%. Their endothelial origin was confirmed by the positive labelling of von Willebrand factor and thrombomodulin, as well as the presence of Weibel-Palade bodies. We applied this method to demonstrate significantly increased levels of EC in venous and arterial human blood samples in patients undergoing heart catheterization. This new whole blood immuno-separation method may be useful in determining endothelial cell injury in vascular disorders.

Release Pattern of the Vascular Plasminogen Activator and Its Inbibitor in Human Postvenous Occlusion Plasma as Assessed by a Spectrophotometric Solid-Phase Fibrin-tPA Activity Assay

Vascular or tissue-type plasminogen activatbr(plasma t-PA) is the circulating physiological fibrinolytic enzyme of endothelial cell origin which function is regulated by fibrin and a specific inhibitor (PAI). To study the pattern of release of t-PA and the behavior of t-PA-PAI complexes in plasma. we determined t-PA activity in 44 healthy subjects before and after 10 min offorearm venous occlusion using a new spectrophotmnetrio solid-phase fibrin-tPA activity assay. The assay is based on 1) the high affinity binding of t-PA tofibrin, and 2) the detection of fibrin-bound t-PA by measuring the release of pNA from a chromogenic substrate in the presence of plasminogeu. Values at.rest were rather undetectable in plasma (0.05 ± 0.03 IU/ml, in 23 out of 44 samples) but were positively detected in all the euglobulins: 0.88 ± 0.68 IU/ml. After venous occlusion the majority ofplasmas (36 out of 44) shoWed a slight increase in t-PA activity (0.65 ± 0.63 IU/ml) as compared to the important level observed in all the euglobulins (9.78 ± 9.58 IU/ml). So, the ratio plasma/euglobulin t-PA activity was very low (0.06) and remained identical in both pre- and postocclusion samples. However, when diluted plasmas were tested the inhibitory effect disappeared and t-PA activity increased indicating that although t-PA circulates in a neutralized state it can be available for fibrinolysis. Since 1) no binding of α2 antiplasmin to fibrin in solid-phase could be demonstrated, 2) there was no correlation between α2 antiplasmin and t-PA activity, and 3) a PAI-depleted plasma with a normal content of α2 antiplasmin did not suppress the activity of t-PA, the inhibitory effect was attributed to PAL Our findings suggest that both t-PA and PAI are released. by venous occlusion and circulates in plasma as a t-PA-PAI complex.

Measurement of Low Molecular Weight Heparin Ex Vivo Activities in Clinical Laboratories Using Various Anti-Xa Assays: Interlaboratory Variability and Requirement for an Agreed Low Molecular Weight Heparin Standard

The only sensitive and convenient assay to assess the biological activity of low molecular weight heparins (LMWHs) is based on the potentiation of activated factor Xa inhibition. Several procedures for measuring the socalled anti Xa activity have been proposed. In this collaborative study including eight laboratories, we have used four different assays (three amidolytic and one clotting based methods) for measuring the anti Xa activity of ex vivo samples obtained after injecting three different LMWHs. The dispersion of the results obtained by calibration against standard heparin could be reduced by using any of the three LMWHs for calibration. A coefficient of variation less than 0.20 between values obtained in different laboratories using a variety of methods seems acceptable. However it is necessary to refer to a common international standard for expressing the results in units and to define, for each of the three products, the therapeutic range.

Asbestos-related disease in upholsterers

Before its use was banned in developed countries, asbestos was widely applied in upholstery. However, the risk of asbestos diseases among upholsterers has only rarely been reported. In this case series, we present a first series of 6 workers employed in small workshops who developed several asbestos-related diseases, including pleural plaques, pleural fibrosis, and asbestosis. Exposures were intermittent and difficult to quantify, but lung asbestos content assessed by bronchoalveolar lavage was high in the 3 patients evaluated. In conclusion, upholstery work should be considered an at-risk occupation for developing asbestos-related diseases during the 20th century.

Platelet Associated u-PA Up-regulates u-PA Synthesis by Endothelial Cells

Adhesion of platelets to endothelium has been shown to induce important changes in endothelial properties. In this study, we examined the effect of platelet-endothelial cell interactions on the expression of urokinase-type plasminogen activator (u-PA) by human microvascular endothelial cells. After incubation of endothelial cells with platelets, a dose-dependent increase in the expression of u-PA Ag was observed and reached a plateau for a ratio of 300 platelets per endothelial cells. The u-PA Ag upregulation resulted from an increase in u-PA mRNA that originated from a synthesis by endothelial cells since no u-PA mRNA was detected in platelets. The platelet-induced u-PA synthesis was inhibited when the endothelial cells were pre-treated with phospholipase C to remove the u-PA receptor, or when the platelets were incubated with an antibody that blocks the binding of u-PA to u-PAR. Taken together, these data indicate that u-PA present on the platelet surface interacts with u-PAR on the endothelial cells and induces the u-PA synthesis. This mechanism may represent a physiological control of platelet-mediated intravascular fibrin deposition.

Evidence for the Expression of Urokinase-type Plasminogen Activator by Human Venous Endothelial Cells In Vivo

Endothelial cells (ECs) in culture synthesize and secrete urokinase-type plasminogen activator (u-PA), but the normal vascular endothelium is believed to synthesize only tissue plasminogen activator (t-PA), which is thought to be responsible for intravascular fibrinolysis. More recently, animal studies have shown that the biological role of u-PA in fibrinolysis has been underestimated, prompting a re-examination of its synthesis by the endothelium. In this study, we investigated whether u-PA was synthesized by non-atherosclerotic endothelial cells in vivo by testing ECs dislodged by venipuncture from 12 normal volunteers and 17 patients admitted for plasmapheresis. The ECs were isolated with an anti-endothelial monoclonal antibody coupled to immunomagnetic beads and characterized by morphology and by labelling for vWF, CD31, and UEA-1 binding. U-PA antigen was found in 50% of the ECs from the normal subjects and in 60% of those from patients. U-PA enzymatic activity on zymograms was detected in 50% of the normal samples and 60% of the patient samples, with the latter being more frequently and more strongly positive. U-PA mRNA was found in all the normal and patient samples tested. The results indicate that u-PA is synthesized by the venous endothelium in vivo but that its expression is highly variable.

Impact of pre-analytical parameters on the measurement of circulating microparticles: towards standardization of protocol

BACKGROUND

Microparticles (MP) are small vesicles of 0.1-1 μm, released in response to activation or apoptosis. Over the past decade, they received an increasing interest both as biomarkers and biovectors in coagulation, inflammation and cancer. Clinical studies were conducted to assess their contribution to the identification of patients at cardiovascular risk. However, among the limitation of such studies, pre-analytical steps remains an important source of variability and artifacts in MP analysis.

OBJECTIVES

Because data from the literature are insufficient to establish recommendations, the objective of the present study was to assess the impact of various pre-analytical parameters on MP measurement. These parameters included the type of collection tube, phlebotomy conditions, transportation practices, centrifugation steps and freezing.

METHODS

MP were assessed by three methods: flow cytometry using a standardized approach, a thrombin generation test (Calibrated Automated Thrombogram(®)) and a procoagulant phospholipid-dependent clotting time assay (STA(®) -Procoag-PPL).

RESULTS

The main results show that the three major pre-analytical parameters which impact on MP-related data are the delay before the first centrifugation, agitation of the tubes during transportation and the centrifugation protocol.

CONCLUSIONS

Based on both this work and literature data, we propose a new protocol that needs to be validated on a larger scale before being applied for multicenter studies.

7-ketocholesterol inhibits Na,K-ATPase activity by decreasing expression of its α1-subunit and membrane fluidity in human endothelial cells

As cholesterol, oxysterols, can insert the cell membrane and thereby modify the functions of membrane-bound proteins. The Na,K-ATPase is very sensitive to its lipid environment, seems to be involved in important endothelial functions as the regulation of nitric oxide (NO) release. The effects of 7-ketocholesterol , an oxysterol present in oxidized LDL, was investigated on Na,K-ATPase in isolated human endothelial cells. Cells were incubated 24h with lecithin-, cholesterol- or 7-ketocholesterol liposomes (6 μg/ml). K+-stimulated paranitrophenyl phosphatase activity, reflecting Na,K-ATPase activity, was evaluated as well as cell viability and lipoperoxidation. The expression of Na,K-ATPase subunits mRNAs and membrane fluidity were also investigated. As Na,K-ATPase and nitric oxide seem to be related, we determined the production of NO and the expression of endothelial NO synthase mRNAs. Na,K-ATPase activity was strongly decreased by 7-ketocholesterol. This decrease, not related to lipoperoxidation, was correlated with a decreased expression of the Na,K-ATPase α1-subunit messengers and with rigidity of plasma membranes. Cholesterol induced similar effects but was less potent than 7-ketocholesterol. Basal NO production and expression of endothelial NO synthase mRNAs were not modified by 7-ketocholesterol. Our new findings demonstrate that 7-ketocholesterol, used at non toxic doses, was very potent to disrupt the transport of ions by Na,K-ATPase and perturb membrane structure. These data demonstrate that 7-ketocholesterol induces endothelial dysfunction without cell death that may contribute to early events in atherosclerosis.

Circulating endothelial cells, microparticles and progenitors: key players towards the definition of vascular competence

The balance between lesion and regeneration of the endothelium is critical for the maintenance of vessel integrity. Exposure to cardiovascular risk factors (CRF) alters the regulatory functions of the endothelium that progresses from a quiescent state to activation, apoptosis and death. In the last 10 years, identification of circulating endothelial cells (CEC) and endothelial-derived microparticles (EMP) in the circulation has raised considerable interest as non-invasive markers of vascular dysfunction. Indeed, these endothelial-derived biomarkers were associated with most of the CRFs, were indicative of a poor clinical outcome in atherothrombotic disorders and correlated with established parameters of endothelial dysfunction. CEC and EMP also behave as potential pathogenic vectors able to accelerate endothelial dysfunction and promote disease progression. The endothelial response to injury has been enlarged by the discovery of a powerful physiological repair process based on the recruitment of circulating endothelial progenitor cells (EPC) from the bone marrow. Recent studies indicate that reduction of EPC number and function by CRF plays a critical role in the progression of cardiovascular diseases. This EPC-mediated repair to injury response can be integrated into a clinical endothelial phenotype defining the ‘vascular competence’ of each individual. In the future, provided that standardization of available methodologies could be achieved, multimarker strategies combining CEC, EMP and EPC levels as integrative markers of ‘vascular competence’ may offer new perspectives to assess vascular risk and to monitor treatment efficacy.

Standardization of platelet-derived microparticle counting using calibrated beads and a Cytomics FC500 routine flow cytometer: a first step towards multicenter studies?

BACKGROUND

Platelet microparticles (PMPs) have proved useful to identify patients with vascular risk. However, PMP counting, which is currently done by flow cytometry (FCM), needs to be standardized.

OBJECTIVES

The objectives were (i) to standardize FCM settings for PMP counts on a routine instrument (Cytomics FC500) using size-calibrated fluorescent beads; (ii) to determine intra-instrument and inter-instrument reproducibility; and (iii) to establish PMP values in healthy subjects.

METHODS

Using a blend of size-calibrated fluorescent beads (0.5 and 0.9 mum) in a fixed numerical ratio (Megamix), we gated PMPs in a restricted size window. To test intra-instrument and inter-instrument reproducibility, annexin V and CD41 coexpression were used to count PMPs in frozen aliquots of the same platelet-free plasma (PFP) over 4 months and in PFP from 10 healthy subjects on three independent flow cytometers.

RESULTS

This calibrated-bead strategy allowed full long-term control of the FCM-based microparticle protocol and reproducible PMP counts over time [coefficient of variation (CV) < 10%]. Optimal settings were easily transferred from one instrument to another, using Megamix as a stable template. Similar PMP counts (CV < 12%) were obtained using the three instruments. With such a standardized FCM protocol, PMP values were established in healthy subjects (n = 60) with significantly higher levels in women than in men [median (1st quartile to 3rd quartile): 1775 microL(-1) (1014-3039 microL(-1)) vs. 656 microL(-1) (407-962 microL(-1))].

CONCLUSIONS

The present strategy provides a new option for PMP count standardization and thus opens the way for multicenter studies.

The standardized Ginkgo biloba extract Egb-761 protects vascular endothelium exposed to oxidized low density lipoproteins

Dietary antioxidants are frequently proposed as protective agents for the vascular endothelium during the onset of atherosclerosis. This protection may occur at two distinct levels. First, they prevent oxidative modification of atherogenic lipoproteins (LDL). Second, they can provide a cellular protection against oxidized LDL-mediated endothelium dysfunction, although this mechanism remains poorly considered in many instances. To gain insight into the mechanism underlying such cellular protection against oxidized LDL, we examined the impact of a popular traditional medicine, an extract from Ginkgo biloba with well-known antioxidant properties, on two endothelial cells properties: cell adhesion and ionic homeostasis. Cellular lipoperoxides levels were also measured as a marker of cellular oxidative stress. Human umbilical-vein endothelial cells were exposed to native (nat-) or oxidized (ox-) LDL, the latter prepared to be compatible with clinically observed levels of oxidation. Although nat-LDL had little effect, ox-LDL increased endothelial adhesive properties (35%, p<0.01) and lipoperoxidation (45%, p<0.01). Na,K-ATPase activity, a key regulator of ionic homeostasis, was significantly decreased after exposure to nat-LDL (30%, p<0.01) and dramatically depressed after exposure to ox-LDL (65%, p<0.001). The standardized preparation of Ginkgo biloba EGb-761 totally protected adhesive properties and endothelial lipoperoxide levels. Moreover, it limited the decrease in Na,K-ATPase activity induced by ox-LDL to levels similar to nat-LDL. This suggests that EGb-761 protects endothelial adhesive properties and helps prevent the disruption of ionic homeostasis. The EGb-761-mediated inhibition of ox-LDL-induced lipoperoxide levels in endothelial cells appears to be an important mechanism by which Ginkgo biloba extract protects endothelial properties.

Vasodilator-stimulated phosphoprotein phosphorylation analysis prior to percutaneous coronary intervention for exclusion of postprocedural major adverse cardiovascular events

BACKGROUND

Despite dual antiplatelet therapy, the rate of major adverse cardiovascular events (MACE) after percutaneous coronary angioplasty remains high. Studies have shown interindividual variations in response to clopidogrel. Furthermore, there is an apparent link between clinical outcomes and clopidogrel resistance.

OBJECTIVES

To investigate the value of platelet reactivity index (PRI), assessed by vasodilator-stimulated phosphoprotein (VASP) phosphorylation analysis, for predicting MACE after percutaneous coronary intervention (PCI) with stent implantation.

METHODS

A prospective monocentric study was performed on 144 patients undergoing PCI. PR was evaluated by VASP phosphorylation analysis 24 h after they received a 300-mg loading dose of clopidogrel. MACE were recorded during a 6-month follow-up. Patients were divided into quintiles according to PRI, as assessed by VASP analysis. The receiver operating characteristic (ROC) curve served to determine the optimal cut-off value of VASP analysis to detect MACE.

RESULTS

Of the 144 patients, 34% had stable angina pectoris, 40% silent ischemia, and 26% low-risk non-ST-segment elevation acute coronary syndrome. During the follow-up, 21 MACE were observed. Patients in quintile 1 of VASP analysis had a significantly lower risk of MACE as compared with those among the four higher quintiles (0 vs. 21, P < 0.01). ROC curve analysis of VASP showed an optimal cut-off value of 50% PR to exclude MACE. The negative predictive value of the test was 100%.

CONCLUSIONS

VASP phosphorylation analysis can evaluate the individual response to clopidogrel loading dose prior to PCI and predict postprocedural MACE.

Elevation of circulating endothelial microparticles in patients with chronic renal failure

BACKGROUND

Chronic renal failure patients are at high risk of cardiovascular events and display endothelial dysfunction, a critical element in the pathogenesis of atherosclerosis. Upon activation, the endothelium sheds microparticles, considered as markers of endothelial dysfunction that also behave as vectors of bioactive molecules.

AIM

To measure plasma levels of endothelial microparticles (EMPs) in chronic renal failure patients (CRF), either undialyzed or hemodialyzed (HD), and to investigate the ability of uremic toxins to induce EMP release in vitro.

METHODS

Circulating EMPs were numerated by flow cytometry, after staining of platelet-free plasma with phycoerythrin (PE)-conjugated anti-CD144 (CD144+ EMP) or anti-CD146 (CD146+ EMP) monoclonal antibodies. Platelet MP (CD41+ PMP), leukocyte MP (CD45+ leukocyte microparticles (LMP)), and annexin-V+ MPs were also counted. In parallel, MPs were counted in supernatant of human umbilical vein endothelial cells incubated with uremic toxins [oxalate, indoxyl sulfate, p-cresol, and homocysteine (Hcy)], at concentrations found in patients.

RESULTS AND CONCLUSIONS

CD144+ EMP and CD146+ EMP levels were significantly higher in CRF and HD patients than in healthy subjects. Furthermore, annexin-V+ MPs were elevated in both groups of uremic patients, and CD41+ PMP and CD45+ LMP were increased in CRF and HD patients, respectively. In vitro, p-cresol and indoxyl sulfate significantly increased both CD146+ and annexin-V+ EMP release. Increased levels of circulating EMP in CRF and HD patients represent a new marker of endothelial dysfunction in uremia. The ability of p-cresol and indoxyl sulfate to increase EMP release in vitro suggests that specific uremic factors may be involved in EMP elevation in patients.

Increased expression of CD146, a new marker of the endothelial junction in active inflammatory bowel disease

BACKGROUND

Crohn's disease (CD) and ulcerative colitis (UC), the 2 major forms of inflammatory bowel diseases (IBD), have been associated with disturbances in vascular physiology, including permeability and angiogenesis, that are in part regulated by the endothelial intercellular junctions. These junctions are composed of several adhesion molecules including the platelet endothelial cell adhesion molecule-1 (PECAM-1, CD31) and the more recently described CD146 (S-Endo1 Ag, MUC18).

AIM

To study the expression of tissue and soluble form of CD146 in patients with CD or UC in relation to disease activity and location. This study was made in comparison with the soluble form of CD31 (sCD31).

RESULTS

In active disease, a high expression of CD146 was observed on endothelial cells in intestinal biopsies from both CD and UC. In addition, we observed a decrease of sCD146 in relation to active disease and extensive location of CD and UC. Lower levels of sCD31 were also detected in active and extensive location of UC, but no difference could be observed in CD.

CONCLUSION

sCD146 is a novel marker of the endothelial intercellular junction that reflects endothelial remodeling more effectively than soluble CD31. Further studies are warranted to determine whether sCD146 will provide a serological assay reflecting alterations in vascular permeability and vessel proliferation in the inflamed IBD intestine.

Elevation of circulating endothelial microparticles in patients with chronic renal failure

BACKGROUND

Chronic renal failure patients are at high risk of cardiovascular events and display endothelial dysfunction, a critical element in the pathogenesis of atherosclerosis. Upon activation, the endothelium sheds microparticles, considered as markers of endothelial dysfunction that also behave as vectors of bioactive molecules.

AIM

To measure plasma levels of endothelial microparticles (EMPs) in chronic renal failure patients (CRF), either undialyzed or hemodialyzed (HD), and to investigate the ability of uremic toxins to induce EMP release in vitro.

METHODS

Circulating EMPs were numerated by flow cytometry, after staining of platelet-free plasma with phycoerythrin (PE)-conjugated anti-CD144 (CD144+ EMP) or anti-CD146 (CD146+ EMP) monoclonal antibodies. Platelet MP (CD41+ PMP), leukocyte MP (CD45+ leukocyte microparticles (LMP)), and annexin-V+ MPs were also counted. In parallel, MPs were counted in supernatant of human umbilical vein endothelial cells incubated with uremic toxins [oxalate, indoxyl sulfate, p-cresol, and homocysteine (Hcy)], at concentrations found in patients.

RESULTS AND CONCLUSIONS

CD144+ EMP and CD146+ EMP levels were significantly higher in CRF and HD patients than in healthy subjects. Furthermore, annexin-V+ MPs were elevated in both groups of uremic patients, and CD41+ PMP and CD45+ LMP were increased in CRF and HD patients, respectively. In vitro, p-cresol and indoxyl sulfate significantly increased both CD146+ and annexin-V+ EMP release. Increased levels of circulating EMP in CRF and HD patients represent a new marker of endothelial dysfunction in uremia. The ability of p-cresol and indoxyl sulfate to increase EMP release in vitro suggests that specific uremic factors may be involved in EMP elevation in patients.

Prognostic value of inducible myocardial ischemia in predicting cardiovascular events after renal transplantation

BACKGROUND

The aims of the present study were to determine the prevalence of inducible myocardial ischemia (IMI) in renal transplant recipients (RTR) more than 50 years old, to identify predictors of IMI, and to search for its prognostic value.

METHODS

Among the 377 renal transplantations performed between 1989 and 1998 in a single institution, 120 were done in patients > or =50 years old, and 97 were recruited for the study. During the last quarter of 1998, all of them underwent an exercise test (EST), an exercise-thallium 201 single photon emission computed tomography coupled with dipyridamole (SPECT), and 81% of them had a dobutamine stress echocardiography (DSE). Patients with IMI subsequently underwent coronary angiography to detect coronary stenosis.

RESULTS

IMI was present in 12 of the 97 patients (10%). The diagnosis was evidenced by EST in four cases, by SPECT in 11 cases, and DSE in three cases. Five of these 12 patients (42%) had significant coronary artery stenosis (> or =50%). Multivariate analysis of several pre- and post-transplant variables evidenced acute rejection and left ventricular hypertrophy as significant correlates of IMI (both P < 0.03). Patients were prospectively followed-up for 48 months for the occurrence of major cardiovascular events. Kaplan-Meier analysis revealed a significant increase in cardiovascular events in the IMI group (P < 0.0001). In addition, the Cox proportional hazards model revealed that IMI and diabetes mellitus had an independent significant effect on the occurrence of major cardiovascular events.

CONCLUSION

IMI was present in 10% of RTR aged > or =50 years, and was predicted by acute rejection and left ventricular hypertrophy. IMI had a strong effect on major cardiovascular events in this population.

Experimental infection of human erythrocytes from alcoholic patients with Bartonella quintana

Bartonella spp. are found in the erythrocytes of their specific natural hosts and B. quintana bacteremia is associated epidemiologically with lice, alcoholism, and homelessness. The aim of our study was to compare the growth and the number of bacteria per erythrocyte in vitro in laboratory-infected red blood cells from alcoholic patients versus normal blood donor erythrocytes. Enumeration of bacteria was performed either with plate counting or with a real-time PCR quantitative assay. Number of bacteria per cell was determined using immunofluorescence assay and laser confocal microscopy. Although the number of bacteria after 4 days of incubation was similar in the two groups of erythrocytes, we found that the distribution of bacteria per erythrocyte in the two groups was different. Erythrocytes from alcoholics contain significantly more bacteria per cell than erythrocytes from blood donors. Our results suggest that there is a link between alcoholism and infections of B. quintana that may be due to the macrocytosis of erythrocytes.

Analysis of donor NK and T cells infused in patients undergoing MHC-matched allogeneic hematopoietic transplantation

We retrospectively analyzed the percentages and absolute numbers of T cells, natural killer (NK) cells and NK cell subsets in cryopreserved samples of either bone marrow or blood non-T cell-depleted allogeneic MHC-matched hematopoietic grafts. Using flow cytometry, we found higher numbers of NK cells in aphereses than in bone marrow collections. We further investigated the distribution of NK cell subsets, defined by the cell surface expression of MHC class I-specific receptors, in these allogeneic grafts. The distribution of NK cell subsets from the two different origins were similar, with the exception of the CD158a/h(+) NK cell subset, whose size appeared to be smaller in bone marrow. The search for relations between the numbers of infused cells and post-transplantation events demonstrated that increasing numbers of infused T cells but not NK cells are related with decreased overall survival. Our study highlights the toxicity of infused T cells but not NK cells in allogeneic MHC-matched hematopoietic grafts. These data pave the way for further trials to investigate the effect of NK cell infusion in MHC-matched allogeneic transplantation, and in particular whether ex vivo NK cell expansion and activation may enhance the anti-tumoral effect of the procedure and decrease its morbidity.

Platelet associated u-PA up-regulates u-PA synthesis by endothelial cells

Adhesion of platelets to endothelium has been shown to induce important changes in endothelial properties. In this study, we examined the effect of platelet-endothelial cell interactions on the expression of urokinase-type plasminogen activator (u-PA) by human microvascular endothelial cells. After incubation of endothelial cells with platelets, a dose-dependent increase in the expression of u-PA Ag was observed and reached a plateau for a ratio of 300 platelets per endothelial cells. The u-PA Ag upregulation resulted from an increase in u-PA mRNA that originated from a synthesis by endothelial cells since no u-PA mRNA was detected in platelets. The platelet-induced u-PA synthesis was inhibited when the endothelial cells were pre-treated with phospholipase C to remove the u-PA receptor, or when the platelets were incubated with an antibody that blocks the binding of u-PA to u-PAR. Taken together, these data indicate that u-PA present on the platelet surface interacts with u-PAR on the endothelial cells and induces the u-PA synthesis. This mechanism may represent a physiological control of platelet-mediated intravascular fibrin deposition.

Identification of CD146 as a component of the endothelial junction involved in the control of cell-cell cohesion

CD146 is a cell-surface molecule belonging to the immunoglobulin superfamily and expressed in all types of human endothelial cells. Confocal and electron microscopic analysis of confluent human umbilical vein endothelial cells (HUVECs) were used to demonstrate that CD146 is a component of the endothelial junction. Double immunolabeling with vascular endothelial cadherin showed that CD146 is localized outside the adherens junction. Moreover, CD146 expression is not restricted to the junction, since part of the labeling was detectable at the apical side of the HUVECs. Interestingly, cell-surface expression of CD146 increased when HUVECs reached confluence. In addition, the paracellular permeability of CD146-transfected fibroblast cells was decreased compared with that of control cells. Finally, CD146 colocalized with actin, was partly resistant to Triton X-100 extraction, and had its expression altered by actin-disrupting agents, indicating that CD146 is associated with the actin cytoskeleton. These results show the regulated expression of CD146 at areas of cell-cell junction and strongly suggest involvement of CD146 as a mediator of cell-cell interaction.

Maternal endothelial soluble cell adhesion molecules with isolated small for gestational age fetuses: comparison with pre-eclampsia

OBJECTIVE

1. To evaluate the activation profile of the endothelium in pregnancies complicated by small for gestational age fetuses compared with pre-eclampsia and normal pregnancy, by measuring the plasma levels of soluble adhesion molecules soluble E-selectin, intercellular cell adhesion molecule-1 and vascular cell adhesion molecule-1. 2. To determine whether soluble adhesion molecules were related to the severity of small for gestational age fetuses and pre-eclampsia.

DESIGN

Observational study.

PARTICIPANTS

Sixteen women with small for gestational age fetuses; 15 women with pre-eclampsia and 15 healthy primigravidae were recruited as controls.

METHODS

Plasma levels of soluble E-selectin, intercellular cell adhesion molecule-1 and vascular cell adhesion molecule-1 were measured by ELISA.

RESULTS

Compared with the healthy controls, soluble E-selectin was significantly increased in both small for gestational age fetuses and pre-eclampsia, whereas intercellular cell adhesion molecule-1 and vascular cell adhesion molecule-1 were increased only in pre-eclampsia. In the small for gestational age fetuses group, soluble E-selectin correlated inversely with the ratio between birthweight and the expected normal birthweight (r = -0.4, P = 0.007). In the pre-eclampsia group, a significant correlation was observed between vascular cell adhesion molecule-1 and blood pressure (r = 0.54, P = 0.039).

CONCLUSIONS

Endothelial activation, reflected by raised levels of soluble E-selectin, is a feature of small for gestational age fetuses and is correlated with the severity of the disease. Differences in the profile of soluble cell adhesion molecules suggest variations in the degrees of endothelial activation between pre-eclampsia and small for gestational age fetuses.

High adenosine and deoxyadenosine concentrations in mononuclear cells of hemodialyzed patients

Infections are one of the most important complications of hemodialysis (HD). The high concentrations of adenosine (Ado) and of its metabolites during HD may contribute to the dialysis-induced immune deficiency through their known ability to alter lymphocyte function. The influence of HD on Ado metabolism was assessed in mononuclear cells through the measurement of (1) the concentrations of nucleosides in mononuclear cells and (2) the activities of mononuclear cell Ado deaminase (MCADA) and Ado kinase, two enzymes involved in Ado concentration regulation. Nine end-stage renal failure hemodialyzed patients (five men and four women; mean age, 69 +/- 10 yr) and eight healthy volunteers (four men and four women; mean age, 53 +/- 19 yr) were included in the study. Before HD, Ado, deoxyadenosine, and inosine concentrations were respectively 2.9-, 2.5-, and 2.5-fold higher in mononuclear cells of patients than in healthy volunteers. During HD, Ado concentration decreased by 34%, whereas inosine concentration increased by 27%. Before HD, MCADA activity level was 2.1-fold lower in patients than in control subjects. After HD, MCADA activity increased by nearly 50% but remained lower than in control subjects. Ado kinase activity level of patients did not differ from that of control subjects and was unchanged by HD. The influence of Ado on in vitro mononuclear cell proliferation and interferon-gamma production also was evaluated. Ado inhibited cell proliferation and interferon-gamma production in a dose-dependent manner, and these inhibitions were stronger for patients than for healthy volunteers. The high concentrations of Ado and deoxyadenosine in mononuclear cells and the low MCADA activity level likely are involved in the immune defect of patients who are undergoing HD.

RT-PCR detection of Na,K-ATPase subunit isoforms in human umbilical vein endothelial cells (HUVEC): evidence for the presence of alpha1 and beta3

The endothelial Na,K-ATPase is an active component in maintaining a variety of normal vascular functions. The enzyme is characterized by a complex molecular heterogeneity that results from differential expression and association of multiple isoforms of both its alpha- and beta-subunits. The aim of the present study was to determine which isoforms of the Na,K-ATPase are expressed in human endothelial cells. HUVEC (human umbilical vein endothelial cells) were used as a model of well known human endothelial cells. The high sensitive method RT-PCR was used with primers specific for the various isoforms of the alpha- and beta-subunits of the Na,K-ATPase. The results show that HUVEC express alpha1-, but not alpha2-, alpha3- or alpha4-isoforms of the catalytic subunit and that beta3- but not beta2- or beta1-isoforms is present in these cells. These findings are in contradiction with our previous detection of Na,K-ATPase isoforms in HUVEC using antibodies (14). Such results raise the technical problem of the specificity of the available antibodies directed against the different isoforms as well as the question of the physiological relevance of the diversity of the Na,K-ATPase isoforms.

Omegacoeur, a Mediterranean nutritional complement, stimulates Na,K-ATPase activity in human endothelial cells

Fatty acids are known as modulators of the vasoactive properties of the vessel wall and can influence the physical and functional properties of cell membrane. The membrane-bound enzyme Na,K-ATPase plays a central role in endothelial function such as vasoconstriction. In a previous study, we have shown that omega3 fatty acids inhibited Na,K-ATPase activity in human endothelial cells. As Mediterranean diet is known to protect from cardiovascular diseases, we have investigated the effects of Omegacoeur, a Mediterranean nutritional complement consisting of omega3, omega6, omega9 fatty acids, garlic and basil, on Na,K-ATPase activity in human endothelial cells (HUVECs). Cells were incubated for 18 hr with pure lecithin liposomes or Omegacoeur-enriched emulsions (4 mg lecithin/ml). Na,K-ATPase and 5'-nucleotidase activities were determined using coupled assay methods on microsomal fractions obtained from HUVECs. Cell fatty acid composition was evaluated by gas chromatography after extraction of lipids and fatty acids methylation. The results showed that Omegacoeur (0.1 mM) increased Na,K-ATPase activity by 40% without changes in 5'-nucleotidase activity. Cells incubated with Omegacoeur preferentially incorporated linoleic acid. Therefore, linoleic acid or others constituents of Omegacoeur could be responsible of the stimulation of the Na,K-ATPase activity that might be related to changes in endothelial membrane fluidity.

Outside-in signaling pathway linked to CD146 engagement in human endothelial cells

CD146 (S-Endo 1 Ag or MUC18) is a transmembrane glycoprotein expressed on endothelial cells on the whole vascular tree. CD146 is located at the intercellular junction where it plays a role in the cohesion of the endothelial monolayer. CD146 engagement initiates an outside-in signaling pathway involving the protein tyrosine kinases FYN and FAK as well as paxillin. Here we report that CD146 engagement by its specific monoclonal antibody in human umbilical vein endothelial cells induces a Ca(2+) influx that is sensitive to thapsigargin and EGTA treatment, indicating that CD146 engagement initiates a store-operated calcium mobilization. In addition, biochemical and pharmacological analysis revealed that CD146 engagement initiates the tyrosine phosphorylation of phospholipase C-gamma, Pyk2, and p130(Cas). Pharmacological inhibition of Ca(2+) flux with 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acetoxymethyl ester and EGTA indicated that an increase in Ca(2+) is required for Pyk2 and p130(Cas) tyrosine phosphorylation. Moreover, a complex association was observed between Pyk2, p130(Cas), and paxillin. These results indicate that CD146 is coupled to a FYN-dependent pathway that triggers Ca(2+) flux via phospholipase C-gamma activation leading subsequently to the tyrosine phosphorylation of downstream targets such as Pyk2, p130(Cas), FAK, and paxillin. In addition to its role in cell-cell adhesion, CD146 is a signaling molecule involved in the dynamics of actin cytoskeleton rearrangement.

Adenosine and hemodialysis in humans

BACKGROUND

Infections and hypotension are serious complications that develop during hemodialysis (HD) treatment. Adenosine (ADO), a strong hypotensive and immunosuppressive agent, may participate in these two HD complications, because high concentrations of ADO metabolites are found in dialyzed human plasma. ADO, which is released by endothelial cells, is quickly transformed into inosine (INO) by plasmatic ADO deaminase (ADA) and mononuclear cell ADO deaminase (MCADA). In plasma, the degradation of ADO into INO and its uptake by red blood cells (RBC) are both very rapid, resulting in the short half-life of ADO in blood.

METHODS

Using liquid chromatography, we evaluated ADO and INO plasma concentrations before and after HD session.

RESULTS

Before the HD session, ADO and INO plasma concentrations were higher in hemodialyzed patients than in controls and in peritoneally dialyzed patients. At the end of the HD session, ADO plasma concentration was increased. ADO plasma concentration for the undialyzed patients was in the same range as that of the controls. Before HD, ADA activity was higher in hemodialyzed patients (559 +/- 349 IU) than in controls (219 +/- 48 IU), and the activity rose during the session (665 +/- 135 IU). ADA activity in the undialyzed patients (222 +/- 80 IU) was in the same range as that of the controls (219 +/- 48 IU). Before the HD session, the MCADA activity (247 +/- 144 IU) was lower than in controls (624 +/- 99 IU). HD did not modify ADO RBC uptake. ADO inhibited mononuclear cell proliferation and interferon-gamma production in humans. Finally, as much as 50 microM INO does not inhibit ADO uptake by RBC and does not modify ADA and MCADA activities.

CONCLUSIONS

These data indicate that chronic HD inhibited MCADA activity and increased ADO plasma concentration. Both high ADO plasma concentration and low MCADA activity may be involved in dialysis-induced immune system failure and thereby favor infectious diseases.

Neutrophil activation in preeclampsia and isolated intrauterine growth restriction

OBJECTIVE

Neutrophils have been implicated in the pathogenesis of preeclampsia. Because preeclampsia and intrauterine growth restriction result from similar placental lesions, the aim of this study was to investigate neutrophil activation in isolated intrauterine growth restriction relative to preeclampsia and uncomplicated pregnancy. Polymorphonuclear neutrophil activation was analyzed by measuring cell surface and soluble cell adhesion molecule expressions.

STUDY DESIGN

L -Selectin (CD62L ) and CD11b surface expressions on polymorphonuclear neutrophils were analyzed in 13 women with preeclampsia, 11 women with isolated intrauterine growth restriction, and 17 age- and gestation-matched control women by means of a standardized quantitative flow cytometry assay. Serum levels of soluble L -selectin were measured by enzyme-linked immunosorbent assay.

RESULTS

Neutrophils from women with isolated intrauterine growth restriction and women with preeclampsia displayed higher levels of CD11b and lower levels of CD62L than did neutrophils from healthy pregnant women. Soluble L -selectin serum levels were significantly increased in the preeclampsia and intrauterine growth restriction groups relative to normal values. No significant difference in the levels of CD11b, CD62L, and soluble L -selectin were observed between women with isolated intrauterine growth restriction and those with preeclampsia. Leukocyte activation was not correlated with disease severity.

CONCLUSION

The observed alteration in polymorphonuclear neutrophil adhesion molecule expressions and increased serum soluble L -selectin levels are consistent with activation of peripheral blood neutrophils occurring in isolated intrauterine growth restriction in a manner similar to that seen in preeclampsia. This evidence of neutrophil activation may help to advance our understanding of the disease process in isolated intrauterine growth restriction.

Circulating endothelial cells in vascular disorders: new insights into an old concept

The endothelial contribution to vascular disorders has been widely documented in experimental models. However, its implication in human pathology is difficult to investigate, owing to the paucity of noninvasive methods and of specific endothelial markers. The enumeration of circulating endothelial cells (CEC) released in peripheral blood after vascular injury represents a direct exploration of the endothelium. For this purpose, we have produced a monoclonal antibody (S-Endo 1), which recognizes CD 146, a molecule expressed on all types of human endothelial cells but absent from haemopoietic cells. Using this antibody, we have designed a specific and sensitive immunocapture test, which allowed us to detect high numbers of CEC in thrombotic, infectious or immunological disorders, while CEC were found to be very rare ( < 3/ml) in normal subjects. This quantitative approach using CEC might prove useful as a marker of vascular wall injury. Their enumeration is of interest in the clinical follow-up of vascular disorders, in the evaluation of therapeutic effectiveness or in the direct diagnosis of infectious diseases involving intra-endothelial microbial agents. Furthermore, an immunological and/or functional study of CEC could allow one to assess their procoagulant and proadhesive properties, as well as their viability, opening new perspectives for CEC investigation in vascular pathology.

Circulating endothelial cells in vascular disorders: new insights into an old concept

The endothelial contribution to vascular disorders has been widely documented in experimental models. However, its implication in human pathology is difficult to investigate, owing to the paucity of noninvasive methods and of specific endothelial markers. The enumeration of circulating endothelial cells (CEC) released in peripheral blood after vascular injury represents a direct exploration of the endothelium. For this purpose, we have produced a monoclonal antibody (S-Endo 1), which recognizes CD 146, a molecule expressed on all types of human endothelial cells but absent from haemopoietic cells. Using this antibody, we have designed a specific and sensitive immunocapture test, which allowed us to detect high numbers of CEC in thrombotic, infectious or immunological disorders, while CEC were found to be very rare ( < 3/ml) in normal subjects. This quantitative approach using CEC might prove useful as a marker of vascular wall injury. Their enumeration is of interest in the clinical follow-up of vascular disorders, in the evaluation of therapeutic effectiveness or in the direct diagnosis of infectious diseases involving intra-endothelial microbial agents. Furthermore, an immunological and/or functional study of CEC could allow one to assess their procoagulant and proadhesive properties, as well as their viability, opening new perspectives for CEC investigation in vascular pathology.

Antiphospholipid and antiprotein syndromes in non-thrombotic, non-autoimmune women with unexplained recurrent primary early foetal loss. The Nîmes Obstetricians and Haematologists Study--NOHA

Various antiphospholipid and/or antiprotein antibodies have been suspected to be associated with recurrent early foetal loss in absence of any habitual aetiology. We conducted a hospital-based case control study on women with no antecedent of thromboembolic or autoimmune disease. We studied 3 groups of 518 women: patients with unexplained primary recurrent early foetal loss, patients with explained episodes and mothers with no previous obstetrical accident. Matching the 3 groups was carried out on the basis of age, number or pregnancies and time elapsed since the end of the last pregnancy. Significant biological markers were then prospectively tested. The various antibodies were shown to be dependent on parity and on the presence of previous foetal loss: cut-off values were thus calculated using data obtained from the group of explained accidents, and adjusted for parity. Only anti-phosphatidylethanolamine IgM [odds ratio: 6.0, 95% confidence interval (2.3-15.7), p = 0.0003], anti-beta2-glycoprotein I IgG [4.4, (1.6-11.7), p = 0.0035] anti-annexin V IgG antibodies [3.2 (1.2-8.1), p = 0.015] and lupus anticoagulant [3.0, (1.3-6.8), p = 0.009], were found to be independent retrospective risk factors for unexplained early foetal loss. These four markers were subsequently found to be, during the following pregnancy, associated with a significant risk of foetal loss despite a low-dose aspirin treatment. In non-thrombotic, non-auto-immune women with unexplained primary recurrent early foetal loss, subgroups of patients with positive anti-phosphatidylethanolamine IgM antibodies, or positive anti-beta2-glycoprotein-I IgG antibodies, or positive anti-annexin V IgG antibodies or lupus anticoagulant must be particularised. This should allow therapeutic trials to be carried in well-defined patients.

Modulation of adenosine concentration by opioid receptor agonists in rat striatum

There is evidence that adenosine and morphine interact in the striatum. However, little is known about the precise role of the opioid receptor subtypes implicated in the modulation of adenosine tissue concentration and in adenosine receptor expression and function. We sought to evaluate, in the absence of withdrawal symptoms, the effects of the short-term administration of selective mu-, delta- or kappa-opioid receptor agonists on adenosine concentration and on adenosine A(2A) receptor function in rat striatum. Adenosine A(2A) receptor was chosen because the neuronal sub-population expressing this receptor coexpresses enkephalin, suggesting that adenosine A(2A) receptor may be regulated by opioid receptor agonists. Oxymorphone hydrochloride mu-opioid receptor agonist, 6 mg/kg/day), +[-(5 alpha,7 alpha, 8 beta)-(-)-N-methyl-N(7-(1-pyrrolidinyl)1-oxaspiro (4.5)dec-8-yl) benzenacetamide] (U69593) (kappa-opioid receptor agonist, 0.75 mg/kg/day), and (+)-4[(alpha R)-alpha-((2S,5R)-4-allyl-2, 5-dimethyl-1-piperazinyl)-3-methoxybenzyl]-N,N-diethylbenzamide) (SNC80) (delta-opioid receptor agonist, 9 mm/kg/day), or vehicle, were administered i.p 3 x daily during 5 days to groups of rats (n=6). We also investigated the effects of opioid receptor agonists on adenosine uptake by striatal cell extracts. We found that administration of mu- or delta-opioid receptor agonists significantly decreased adenosine uptake in striatal cell extracts and increased adenosine concentration (mean+24% and +45% for mu- and delta-opioid receptor agonist, respectively, relative to controls). None of the receptor agonists tested induced obvious modifications of adenosine A(2A) receptor function. However, the delta-opioid receptor agonist induced an increase in adenosine A(2A) mRNA expression (mean 44%). We conclude that mu and delta receptor agonists inhibit adenosine uptake by striatal cell extracts and increase adenosine concentrations in rat striatum.