Augmenting pharmacotherapy with neuromodulation techniques for the treatment of bipolar disorder: a focus on the effects of mood stabilizers on cortical excitability

Introduction: Mood stabilizers and antipsychotics have been demonstrated to be effective in Bipolar Disorder, with lithium as the gold standard. However, the presence of adverse events and treatment-resistance is still a relevant issue. To this respect, the use of brain stimulation techniques may be considered as an augmentation strategy, with both Transcranial Magnetic Stimulation (TMS) and Transcranial Direct Current Stimulation (tDCS) having shown some level of efficacy in bipolar patients although clinical trials are still not sufficient to draw any conclusion. Areas covered: The authors have conducted a systematic review of the literature, in order to evaluate the role of mood stabilizers on neural activity and cortical excitability. Furthermore, the article reviews neuromodulation techniques and highlights the potential of integrating pharmacological first-line therapies with these techniques to treat BD patients. Expert opinion: The combination of neuromodulation techniques and available pharmacotherapies is a valuable opportunity which is not undermined by specific effects on cortical excitability and could improve BD patient outcome. Neurostimulation techniques may be considered safer than antidepressant treatments in BD, with a lower level of manic switches and may represent a new treatment strategy in BD depressive episodes.

New Direct Assay of Free Protein S Antigen Applied to Diagnosis of Protein S Deficiency

Congenital deficiencies of protein S (PS) are associated with thrombophilia. Their characterization and classification have been hampered by the complex physiology of the protein C-protein S system and the poor standardization and reliability of laboratory assays. The free active form of protein S is usually determined by immunoassay using polyclonal antibodies in the plasma supemate after polyethyleneglycol (PEG) precipitation. A new one step ELISA using two monoclonal antibodies specific for distinct epitopes of the free form of protein S has been developed for the direct measurement of free PS in untreated plasma.

We have tested two ELISA assays for free PS. One assay was based on the PEG precipitation (Asserachrom PS®, Stago, Asnières, France) whereas the other was a one step ELISA assay (Asserachrom® free PS, Stago). Values were obtained in 35 PS deficient patients recruited among 500 consecutive patients evaluated by the laboratory for diagnosis of congenital disorders of coagulation. Values were compared to those obtained in 50 patients with no PS deficiency matched for age and sex with the PS deficient patients as well as in 33 normal subjects and in 12 pregnant women. Strong correlation was found between the two tests (r = 0.81, p<10-5) in the entire population (n = 130), as well as in the separate groups. The new one step ELISA was more accurate than the PEG free PS determination. Determination of PS activity and antigens allowed us to separate quantitative and qualitative deficiencies. Among the qualitative deficiencies, isolated decrease in PS activity was the most frequent defect observed (66%). This fact questions the substitution of PS activity assays by the one step antigenic free PS ELISA assay.

Increase in Plasma Concentrationof Plasminogen Activator Inhibitor, Fibrinogen, von Willebrand Factor, Factor VIII: Cand in Erythrocyte Sedimentation Rate with Age

Elderly patients have previously been shown to have an increased plasma concentration of tissue plasminogen activator (t-PA) antigen (t-PAAg). Since the concentration of t-PA Ag dependson both free t-PA and t-PA complexed with inhibitors, mainly plasminogen activator inhibitor (PA inhibitor), we have investigated the relationship between the plasma concentration of PA inhibitor and age in 20 elderly and 20 young individuals. Elderly individuals showed a slight increase in PA inhibitor, in parallel with increase on others, acute-phase proteins, fibrinogen, von Willebrand factor, factor VIII :C, and the erythrocyte sedimentation rate. The increase i PA inhibitor as well as other acute-phase proteins in the elderly may be significant in relation to the increased incidence of thrombotic disease.

Increased PA-Inhibitor Levels in the Postoperative Period – No Cause-Effect Relation with Increased Cortisol

It has been reported that the level of PA-inhibitor increases in postoperative patients and on the other hand that glucocorticoids increase the PA-inhibitor level in cell culture. Because surgery is associated with increased plasma cortisol level, a relation between the postoperative increase in plasma cortisol and PA-inhibitor levels was looked for.

Blood samples were collected from 8 patients undergoing extensive abdominal surgery, before operation and postoperatively at 2 hr, 4 hr, 24 hr and daily for 7 days. Plasma cortisol and PA-inhibitor were increased 2 hr after surgery, when there was a significant correlation (p <0.05). The maximum increase was at 24 hr and the values fell to normal on day 6. An increase in t-PA related antigen (t-PA R:Ag) and a decrease in euglobulin fibrinolytic activity (EFA) also occurred.

In 7 controls 0.25 mg ACTH was given intravenously and blood was collected after ½, 1, 2, 4, 6 hr. Although the increase in plasma cortisol level following ACTH was comparable to that observed after surgery the increase was not associated with significant change in PA-inhibitor level, t-PA R: Ag or EFA.

A cause-effect relationship between the increased plasma cortisol and PA-inhibitor level could not be shown. The mechanism of the postoperative increase in PA-inhibitor thus remains unknown.

Deficient t-PA Release and Elevated PA Inhibitor Levels in Patients with Spontaneous or Recurrent Deep Venous Thrombosis

The fibrinolytic system was investigated in 120 patients with spontaneous or recurrent deep vein thrombosis (DVT) without any known organic disease able to explain by itself the occurrence of a thrombosis and without any known defect of antithrombin III, Heparin Cofactor II, Protein C, or Protein S. The assays included: Euglobulin fibrinolytic activity (EFA), tissue-type plasminogen activator related antigen (t-PA-Ag) and plasminogen activator inhibitor activity (PA inhibitor), which were measured before and after 10 min of venous occlusion (V. O.). On the basis of the results, the patients could be classified in 3 groups:good responders with an at least two-fold increase of EFA after venous occlusion (n = 76), poor responders with a lesser increase of EFA due to deficient release of t-PA (n = 12), and poor responders with a normal t-PA release but an increased level of PA-Inhibitor (n = 32).

The poor responders due to deficient t-PA release (10% of total) had a higher incidence of recurrence of deep vein thrombosis, than the other groups (p <0.01). An overall correlation was found between the level of PA-Inhibitor activity and the triglyceride level (r = 0.40, p <0.01), suggesting that these elevations may be due to a common cause, at least in some of the patients.

It is concluded that a poor fibrinolytic response to venous occlusion occurs in 35 percent of DVT patients. Poor responders however fall into two categories, one fourth with deficient t-PA release who have a high risk for recurrent venous thrombosis, and three fourth with increased PA-Inhibitor levels which may be associated with underlying diseases also causing hypertriglyceridemia. Further elucidation of the correlation between recurrent venous thrombosis and deficient fibrinolysis is expected to result in more specific and adequate treatment and prevention of DVT.

Detection of Plasminogen Activator Inhibitor-1 (PAI-1) mRNA in Human Megakaryocytes by In Situ Hybridization

Platelets have been described to contain a large proportion of the circulating plasminogen activator inhibitor type 1 (PAI-1) which is released on platelet activation. This protein could be taken up by platelets from the plasma or synthesized by megakaryocytes (MKs). Recently, PAI-1 mRNA has been detected in a human megakaryoblastic leukemia cell line (MEG-01) by the polymerase chain reaction (PCR). However, a direct demonstration of its presence in normal human MKs is lacking.

In order to prove directly the megakaryocytic origin of platelet PAI-1, the MEG-01 cell line, human bone marrow enriched in MKs, and bone marrow smears from allogeneic bone marrow transplantation donors were investigated for the presence of PAI-1 mRNA using in situ hybridization (ISH). Specimens of bone marrow were first stained with May-Grunwald Giemsa (MGG) for cell identification according to their morphology. Subsequently, the same slides were used for ISH. PAI-1 mRNA was clearly demonstrated in the MEG-01 cell line and in MKs, and its presence correlated with the detection of PAI-1 antigen by immunocytochemistry. PAI-1 mRNA was also detected in morphologically characterized mature granulocytes of marrow samples.

Daytime Fluctuations of Plasminogen Activator Inhibitor 1 (PAI-1) in Populations with High PAI-1 Levels

The mechanism underlying diurnal variations in PAI-1 as well as the cellular origin of PAI-1 in subjects with high PAI-1 levels are unknown. We evaluated diurnal changes (8:00 am vs 4:00 pm) in PAI-1 (functional and immunological assays), t-PA Ag and t-PA/PAI-1 complex levels in controls and subjects with high PAI-1 levels. Three test groups were recruited among obese hyperinsulinmic subjects, emergency care unit patients with inflammatory syndrome or infection and pregnant women.

The classical afternoon decrease of PAI-1 level was observed in controls and obese subjects but its amplitude was greater in the latter. The decrease in t-PA Ag and t-PA/PAI-1 complex levels was the same in controls and in obese. As, in previous studies, elevated PAI-1 levels have been correlated with insulin resistance and a decrease in insulin sensibility has been described in the early morning, it is proposed that this “dawn phenomenon” could be implicated in the circadian variations of PAI-1 in controls and could be amplified in obese subjects. Great variability in PAI-1, t-PA Ag or t-PA/PAI-1 complex levels was observed in patients with acute inflammatory syndrome or infection for whom classical biorhythms are suppressed. No diurnal changes in PAI-1 and other fibrinolytic parameters were observed in patients with inflammatory syndrome or in pregnant women suggesting that other sources and/or other regulatory mechanisms of PAI-1 production are involved.

Potentiation by Heparin Fragments of Thrombolysis Induced with Human Tissue-Type Plasminogen Activator or Human Single-Chain Urokinase-Type Plasminogen Activator

The effect of heparin and of two low molecular weight (low M r) fractions of heparin on thrombolysis with recombinant human tissue-type plasminogen activator (rt-PA, Genentech Inc., So. San Francisco, CA) or human single chain urokinase-type plasminogen activator (scu-PA, Sandoz AG, Basle, Switzerland) was measured in a rabbit jugular vein thrombosis model. Four bolus injections of 200 anti-Factor Xa units/kg body weight of heparin (Liquemine, Hoffmann-La Roche, Basle, Switzerland), of 90 units/kg of CY 216 (Choay, Paris, France) or of 90 units/kg of CY 222 (Choay, Paris, France) were given intravenously, immediately after the start of the infusion of rt-PA or scu-PA and at hourly intervals during their intravenous infusion over 4 hours. The bolus injections resulted in anti-Factor Xa levels in plasma of 5.7 ± 1.2 units/ml just before the repeat bolus injections of heparin with corresponding values of 3.9 ± 0.2 units/ml for CY 216 and 1.6 ± 0.2 units/ml for CY 222.

Thrombolysis with 0.25 mg/kg rt-PA was 36 ± 1 percent (n = 9) in the absence of anticoagulant, 40 ± 1 percent (n = 7, p <0.05) in the presence of heparin, 49 ± 5 percent (n = 7, p <0.02) with CY 216 and 62 ± 5 percent (n = 7, p <0.01) with CY 222. Thrombolysis with 0.5 mg/kg scu-PA was 23 ± 1 percent (n = 4) without heparin, and increased to 24 ± 1 percent (n = 4, p >0.1) with heparin, to 32 ± 2 percent (n = 4, p <0.01) with CY 216 and to 33 ± 3 percent (n = 4, p <0.01) with CY 222.

It is concluded that, at these high doses, the two low M r heparin fractions CY 216 and CY 222, potentiate thrombolysis by rt-PA and scu-PA in this animal model.

Plasma TAFI Antigen Variations in Healthy Subjects

The Thrombin Activatable Fibrinolysis Inhibitor (TAFI) is a recently described inhibitor of fibrinolysis. The physiological variations of plasma TAFI antigen are not well known. We studied TAFI antigen values in healthy populations with a commercially available kit from Milan Analytica (Switzerland). Broad range of TAFI antigen values (from 41% to 259%) was found in a population of 249 healthy individuals. Gender as well as pregnancy did not influence mean values of TAFI antigen. There was a positive correlation between TAFI antigen and age in female (r = 0.28; p <0.05) but not in male populations. Mean TAFI antigen value of a black African male group [mean ± SD (range): 87 ± 23 (39-144%)] was significantly lower than the one of age matched Caucasian men [114 ± 34 (52-259%)] (p <0.0001). TAFI antigen values were very stable within individuals, they did not significantly vary on day time or at several months period.

Thus, in contrast to large inter-individual variations, TAFI antigen levels are quite stable within individuals.

Adipose Tissue Expression of Gelatinases in Mouse Models of Obesity

Following the observation by Brown et al. (Am J Physiol 1997; 272: C937-49) that primary rat adipocytes in culture secrete gelatinase A (MMP-2), we have evaluated gelatinase expression in adipose tissue with the use of mouse models of obesity. Wild-type mice were kept on a standard fat diet (SFD) or on a high fat diet (42% fat, HFD) and genetically obese db/db mice were kept on SFD; gonadal and subcutaneous fat pads were removed and analysed ex vivo. These studies revealed that: 1) the HFD induced adipocyte hypertrophy; 2) after 32 weeks, significantly higher levels of 70 kDa (p <0.05) and 65 kDa proMMP-2 (p < 0.01) were observed in extracts of gonadal fat pads of mice on HFD; 3) the contribution of active MMP-2 to the total level was comparable in SFD and HFD groups (20 to 30%); and 4) gelatinase B (MMP-9) was not consistently detected. These findings were confirmed by gelatin zymography and by mRNA determination using competitive RT-PCR. The presence of MMP-2 in the adipose tissue was confirmed immunologically and its localization in adipocytes revealed by immunogold electron microscopy. The potential functional role of MMP-2 in adipose tissue remains to be determined.

Protein S Heerlen mutation heterozygosity is associated with venous thrombosis risk

Hereditary Protein S (PS) deficiency is a rare coagulation disorder associated with an increased risk of venous thrombosis (VT). The PS Heerlen (PSH) mutation is a rare S501P mutation that was initially considered to be a neutral polymorphism. However, it has been later shown that PSH has a reduced half-life in vivo which may explain the association of PSH heterozygosity with mildly reduced levels of plasma free PS (FPS). Whether the risk of VT is increased in PSH carriers remains unknown. We analyzed the association of PSH (rs121918472 A/G) with VT in 4,173 VT patients and 5,970 healthy individuals from four independent case-control studies. Quantitative determination of FPS levels was performed in a subsample of 1257 VT patients. In the investigated populations, the AG genotype was associated with an increased VT risk of 6.57 [4.06–10.64] (p = 1.73 10⁻¹⁴). In VT patients in whom PS deficiency was excluded, plasma FPS levels were significantly lower in individuals with PSH when compared to those without [72 + 13 vs 91 + 21 UI/dL; p = 1.86 10⁻⁶, mean + SD for PSH carriers (n = 21) or controls (n = 1236) respectively]. We provide strong evidence that the rare PSH variant is associated with VT in unselected individuals.

α1 -antitrypsin Pittsburgh and plasmin-mediated proteolysis

Essentials Patients with α-1-antitrypsin (α1-AT) Pittsburgh exhibit a mild bleeding tendency. A new case of α1-AT Pittsburgh with suspected high antifibrinolytic potential was studied. We showed that α1-AT Pittsburgh inhibits tissue plasminogen activator and plasmin. The antifibrinolytic potential of the variant contributes to explaining the mild bleeding phenotype.

SUMMARY

α1 -Antitrypsin (α1 -AT) Pittsburgh has a Met358 to Arg substitution at the reactive Met-Ser site of α1 -AT, which enables the protein to act as a potent thrombin inhibitor. Four patients with α1 -AT Pittsburgh have been described to date. An additional young girl was recently diagnosed with α1 -AT Pittsburgh in our center after presenting with a large hematoma in the forearm. Interestingly, all of these patients showed a potent thrombin inhibitor in the plasma and a mild bleeding phenotype. This observation suggests that the in vivo consequences of the mutation may contribute to the maintenance of normal hemostatic balance. We assessed inhibition of the fibrinolytic system by the variant protein by evaluating the fibrinolysis inhibitory potential of the patient's plasma, purified wild-type α1 -AT and purified Pittsburgh α1 -AT with an electrophoretic zymography system, western blotting, and clot fibrinolysis. Our results indicate that the patient's plasma and purified α1 -AT Pittsburgh have strong potential to inhibit tissue-type plasminogen activator and plasmin.

[Diagnosis of inherited thrombocytopenia]

Inherited thrombocytopenias are rare, heterogenous and probably under-diagnosed because often classified as autoimmune thrombocytopenia. About 20 genes were described responsible for these thrombocytopenias. Precise diagnosis is necessary because the prognosis is different and some of them can evolve into hemopathies. First of all, it is important to gather a body of evidence to orientate towards an inherited cause: presence of the thrombocytopenia since childhood and of other family cases is a strong argument. Secondly, it is difficult to target the genetic investigations that settle the precise diagnosis. Genetic variants responsible for inherited thrombocytopenias affect different stage during megakaryocytopoiesis and cause thrombocytopenias with distinct characteristics. Presence of extra-hematological features, platelets' size measurement and evaluation of bone marrow megakaryocyte morphology when it is possible allow a primary orientation. We propose a diagnostic approach considering extra-hematological features, mode of inheritance, morphology, molecular and functional platelets' studies and bone marrow megakaryocyte morphology in order to better target genetic study. Nevertheless, despite this approach, some inherited thrombocytopenias remain still unexplained and could benefit from new methods of new generation sequencing in the future.

Systemic inhibition and liver-specific over-expression of PAI-1 failed to improve survival in all-inclusive populations or homogenous cohorts of CLP mice

BACKGROUND

The role of plasminogen activator inhibitor type-1 (PAI-1) in abdominal sepsis remains elusive.

OBJECTIVES

To study the influence of inhibition and over-expression of PAI-1 upon survival in cecal ligation and puncture (CLP) sepsis.

METHODS

(i) Mice underwent moderate CLP and received 10 mg kg(-1) of either monoclonal anti-PAI-1 (MA-MP6H6) or control (MA-Control) antibody intravenously at 0, 18 or 30 h post-CLP. The 30-h treatment group was additionally stratified into mice predicted to survive (P-SUR) or die (P-DIE) based on IL 6 measured at 24 h post-CLP. (ii) PAI-1 expression was induced with pLIVE.PAI-1 plasmid administered 72 h pre-CLP. Blood was sampled for 5 days and survival was monitored for 28 days.

RESULTS

MA-MP6H6 effectively neutralized active PAI-1 and fully restored fibrinolysis while PAI-1 over-expression was liver-specific and correlated with PAI-1 increase in the blood. Without stratification, MA-MP6H6 co-/post-treatment conferred no survival benefit. Prospective stratification (IL-6 cut-off: 14 ng mL(-1) ) suggested increased mortality by MA-MP6H6 treatment in P-SUR that reached 30% difference (vs. MA-Control; P < 0.05) after a retrospective cut-off readjustment to 3.3 ng mL(-1) for better P-SUR homogeneity. Subsequent prospective anti-PAI-1 treatment in P-SUR mice with 3.3 ng mL(-1) cut-off demonstrated a negative but statistically insignificant effect: mortality was higher by 17% after MA-MP6H6 vs. MA-Control. Over-expression of PAI 1 did not alter post-CLP survival. Neither PAI-1 inhibition nor over-expression meaningfully modified inflammatory response and/or organ function.

CONCLUSIONS

Restoration of fibrinolysis in early abdominal sepsis was not beneficial and it may prove detrimental in subjects with the lowest risk of death, while preemptive PAI-1 up-regulation at the current magnitude was not protective.

Risk assessment of venous thrombosis in families with known hereditary thrombophilia: the MARseilles-NImes prediction model

BACKGROUND

Although predicting the risk of venous thrombosis (VT) in an individual from a family with inherited thrombophilia is of major importance, it is often not feasible.

OBJECTIVES

To develop a simple risk assessment model that improves prediction of the risk of VT for individuals of families with inherited thrombophilia.

PATIENTS/METHODS

1201 relatives from 430 families with inherited thrombophilia (deficiencies of antithrombin, protein C or protein S, and the factor V Leiden and F2 20210A mutations) were recruited at the referral center for thrombophilia in Marseilles, France, from 1986 to 2008. One hundred and twenty-two individuals had a personal history of VT. Sixteen preselected clinical and laboratory variables were used to derive the VT risk score.

RESULTS

The scores based on the 16 variables and on the five most strongly associated variables performed similarly (areas under receiver operating characteristic curves of 0.85 and 0.83, respectively). For the five-variable score, named the MARNI score, derived from family history score of VT, von Willebrand factor antigen levels, age, severity of thrombophilia, and FGG rs2066865, the risk of VT ranged from 0.2% for individuals with a score of 0 (n = 186) to > 70% for individuals with a score of ≥ 7 (n = 27). The model was validated with an internal bootstrap method.

CONCLUSIONS

With the use of a simple scoring system, assessment of the risk of VT in subjects from families with inherited thrombophilia can be greatly improved. External validation is now needed to replicate these findings.

Risk assessment of venous thrombosis in families with known hereditary thrombophilia: the MARseilles-NImes prediction model

BACKGROUND

Although predicting the risk of venous thrombosis (VT) in an individual from a family with inherited thrombophilia is of major importance, it is often not feasible.

OBJECTIVES

To develop a simple risk assessment model that improves prediction of the risk of VT for individuals of families with inherited thrombophilia.

PATIENTS/METHODS

1201 relatives from 430 families with inherited thrombophilia (deficiencies of antithrombin, protein C or protein S, and the factor V Leiden and F2 20210A mutations) were recruited at the referral center for thrombophilia in Marseilles, France, from 1986 to 2008. One hundred and twenty-two individuals had a personal history of VT. Sixteen preselected clinical and laboratory variables were used to derive the VT risk score.

RESULTS

The scores based on the 16 variables and on the five most strongly associated variables performed similarly (areas under receiver operating characteristic curves of 0.85 and 0.83, respectively). For the five-variable score, named the MARNI score, derived from family history score of VT, von Willebrand factor antigen levels, age, severity of thrombophilia, and FGG rs2066865, the risk of VT ranged from 0.2% for individuals with a score of 0 (n = 186) to > 70% for individuals with a score of ≥ 7 (n = 27). The model was validated with an internal bootstrap method.

CONCLUSIONS

With the use of a simple scoring system, assessment of the risk of VT in subjects from families with inherited thrombophilia can be greatly improved. External validation is now needed to replicate these findings.

In vivo assessment of murine elastase-induced abdominal aortic aneurysm with high resolution magnetic resonance imaging

OBJECTIVES

There are, to date, no published non-invasive or longitudinal studies performed in mice to measure aortic diameter and wall thickness in an elastase-induced abdominal aortic aneurysm. This MRI study at 11.75 T aimed at evaluating the reliability of longitudinal in vivo aortic diameter and wall thickness measurements in this particular model.

METHODS

Adult male C57BL/6 mice underwent transient elastase or heat-inactivated elastase perfusion (controls). Aortic dilatation was measured before, during and immediately after elastase perfusion, and again 14 days after, with a calibrated ocular grid. MRI was performed just before initial surgery and at day 14 before harvest using an 11.75 T MR microscopy imager.

RESULTS

Aortic diameter was significantly greater in elastase-perfused mice compared to controls as measured by optic grid (1.150 ± 0.153 mm vs 0.939 ± 0.07 mm, P = 0.038) and according to MRI measurement of the outer diameter on spin echo images (1.203 ± 0.105 mm vs 1070 ± 0.048 mm, P = 0.0067). Aortic wall thickness was found to be significantly increased in elastase-perfused mice at day 14.

CONCLUSIONS

This study demonstrates in the mouse elastase-induced aneurysm model that characterization of aneurysm development by its inner and outer vessel diameter and vessel wall thickness can be carried out longitudinally using high resolution MRI without significant mortality.

Prothrombin G20210A carriers the genetic mutation and a history of venous thrombosis contributes to thrombin generation independently of factor II plasma levels

SUMMARY BACKGROUND

The prothrombin (PT) G20210A gene mutation is a common risk factor for venous thrombosis (VT), which is mainly mediated through an increase in factor II (FII) plasma levels. High FII plasma levels may act through an increase in endogenous thrombin potential (ETP) a key step in hemostasis and thrombosis. While FII may be the main contributor to ETP in PT G20210A carriers, the knowledge of other environmental or genetic factors influencing ETP may help to better identify those at risk of VT.

AIMS

ETP was determined in 472 non-carriers of PT G20210A (PT-) and in 325 unrelated carriers of PT G20210A (PT+) with (symptomatic n = 158) or without (asymptomatic, n = 167) a history of VT. All PT+ were heterozygous and free of other thrombophilic defects.

RESULTS

ETP was higher in asymptomatic PT+ than in PT- (2038 +/- 371 vs. 1616 +/- 267 nmol L(-1) min; P < 0.0001). ETP was significantly higher in symptomatic PT+ than in controls PT+ (2129 +/- 430 vs. 2038 +/- 371 nmol L(-1) min; P = 0.01). Multivariate analyses evidenced the importance of FII and fibrinogen plasma levels in determining ETP.

DISCUSSION

After taking these variables into account, a personal history of VT remained associated with ETP in PT+ carriers. Moreover, PTG20210A still contributes to ETP after consideration of FII levels.

CONCLUSION

In conclusion, the increase in ETP observed in carriers is not entirely explained by higher FII or fibrinogen plasma levels but also by the history of VT.

The inflammatory receptor CD40 is expressed on human adipocytes: contribution to crosstalk between lymphocytes and adipocytes

AIMS/HYPOTHESIS

Obesity is associated with adipose tissue inflammation. The CD40 molecule, TNF receptor superfamily member 5 (CD40)/CD40 ligand (CD40L) pathway plays a role in the onset and maintenance of the inflammatory reaction, but has not been studied in human adipose tissue. Our aim was to examine CD40 expression by human adipocytes and its participation in adipose tissue inflammation.

METHODS

CD40 expression was investigated in human whole adipose tissue and during adipocyte differentiation by real-time PCR, Western blot and immunohistochemistry. The CD40/CD40L pathway was studied using recombinant CD40L (rCD40L) in adipocyte culture and neutralising antibodies in lymphocyte/adipocyte co-culture.

RESULTS

CD40 mRNA levels in subcutaneous adipose tissue were higher in the adipocyte than in the stromal-vascular fraction. CD40 expression was upregulated during adipocyte differentiation. Addition of rCD40L to adipocytes induced mitogen activated protein kinase (MAPK) activation, stimulated inflammatory adipocytokine production, and decreased insulin-induced glucose transport in parallel with a downregulation of IRS1 and GLUT4 (also known as SCL2A4). rCD40L decreased the expression of lipogenic genes and increased lipolysis. CD40 mRNA levels were significantly higher in subcutaneous adipose tissue than in visceral adipose tissue of obese patients and were positively correlated with BMI, and with IL6 and leptin mRNA levels. Lymphocyte/adipocyte co-culture led to an upregulation of proinflammatory adipocytokines and a downregulation of leptin and adiponectin. Physical separation of the two cell types attenuated these effects, suggesting the involvement of a cell-cell contact. Blocking the CD40/CD40L interaction with neutralising antibodies reduced IL-6 secretion from adipocytes.

CONCLUSIONS/INTERPRETATION

Adipocyte CD40 may contribute to obesity-related inflammation and insulin resistance. T lymphocytes regulate adipocytokine production through both the release of soluble factor(s) and heterotypic contact with adipocytes involving CD40.

Activated thrombin activatable fibrinolysis inhibitor levels are associated with the risk of cardiovascular death in patients with coronary artery disease: the AtheroGene study

BACKGROUND

Thrombin activatable fibrinolysis inhibitor (TAFI) attenuates fibrinolysis. Results on the association between TAFI levels and the risk of coronary artery disease (CAD) are inconsistent.

OBJECTIVES

We investigated the association between TAFI levels and the risk of cardiovascular events in CAD.

PATIENTS/METHODS

1668 individuals with angiographically proven CAD at baseline were followed for a median of 2.3 years, as part of the prospective AtheroGene cohort. Fifty-six deaths from cardiovascular (CV) causes and 35 non-fatal CV events were observed.

RESULTS

At baseline, three TAFI measurements were available: one evaluating the total amount of TAFI (t-TAFI), one measuring the TAFIa/TAFIai amount, and the last the released activated peptide (TAFI-AP). TAFIa/TAFIai levels were associated with increased risk of CV death [hazard ratio (HR) for one tertile increase, 2.38 (1.56-3.63); P < 10(-4)]. This association remained significant after adjustment for conventional risk factors, CRP levels, white blood count and markers of thrombin generation and fibrinolysis [HR = 1.69 (1.07-2.67); P = 0.01]. In addition, CPB2 gene polymorphisms explained 12%, 6%, and 3% of t-TAFI, TAFIa/TAFIai and TAFI-AP levels, respectively, but none was associated with CV events.

CONCLUSIONS

The amount of activated TAFI, measured by TAFIa/TAFIai ELISA, but not of the t-TAFI is independently associated with the risk of CV death.

Pharmacokinetics and pharmacodynamics of a new highly secured fibrinogen concentrate

BACKGROUND

Inherited afibrinogenemia is a rare autosomal recessive disorder characterized by the absence or trace amounts of plasma fibrinogen inducing varying bleeding tendencies. Little is known about the pharmacokinetics of plasma-derived fibrinogen concentrates used in the treatment of afibrinogenemic patients.

OBJECTIVE

This open, prospective, multicenter study assessed the pharmacokinetic and pharmacodynamic profiles of FIBRINOGENE T1 (FGT1; LFB, Les Ulis, France), a human fibrinogen concentrate treated with three specific biological safety steps.

PATIENTS/METHODS

Five adult patients with congenital afibrinogenemia received a single infusion of 0.06 g kg(-1) of FGT1. Plasma samples drawn up to day 14 were assayed for fibrinogen antigen and activity and for coagulation parameters in a central laboratory.

RESULTS

Fibrinogen antigen and activity were similar and highly correlated, with very low between-patient variability for pharmacokinetic parameters. Fibrinogen levels increased rapidly and significantly, with a mean plasma concentration of 1.39 g L(-1) being achieved 1 h after the end of the infusion, leading to almost complete in vivo recovery (94%). The mean half-life was 3.4 days, with slow linear elimination, and the distribution was mainly restricted to the vascular compartment. Coagulation parameters were normalized after the infusion and during the following 6-10 days. FGT1 was well tolerated overall.

CONCLUSIONS

FGT1 behaves like natural functional fibrinogen, and its pharmacokinetic properties are in line with those expected from a fibrinogen concentrate. Our findings suggest that FGT1 can restore efficient hemostasis in afibrinogenemic patients, and predict good clinical efficacy.

Chronic plasminogen activator inhibitor-1 (PAI-1) overexpression dampens CD25+ lymphocyte recruitment after lipopolysaccharide endotoxemia in mouse lung

BACKGROUND

Plasma plasminogen activator inhibitor-1 (PAI-1) level rises during sepsis and confers a worse prognosis. PAI-1 participation to sepsis has been poorly documented and was mainly associated with fibrin deposits. Beside fibrin deposits, increased tissue PAI-1 expression may contribute to the poor outcome of endotoxemia through other mechanisms.

OBJECTIVE AND METHODS

During lipopolysaccharide (LPS) challenge, the role of PAI-1 in the early phase of inflammation was examined in the lungs of transgenic mice that either overexpress or lack the PAI-1 gene (PAI-1Tg or PAI-1(-/-)).

RESULTS

Analysis of leukocytes revealed that neutrophil and macrophage infiltrations did not differ for PAI-1Tg and wild-type (WT) mice. Remarkably, CD25+ lymphocyte infiltration was totally blunted in PAI-1Tg lungs and inversely correlated with fibrin depositions. In parallel, mRNA levels of the regulatory T cell (Treg) markers FoxP3, CTLA-4, and GITR were significantly lower in PAI-1Tg than in WT lungs after LPS challenge. These data are supported by opposite results in PAI-1(-/-) lungs. The systemic compartments (spleen and peripheral blood) showed no decrease in CD25+, CD4+ CD25+ lymphocytes, and Treg markers in PAI-1Tg mice after LPS injection compared with WT mice. In addition, plasma and lung concentrations of interleukin-6 (IL-6) and macrophage inflammatory protein-1alpha (MIP-1alpha) were significantly higher in PAI-1Tg mice than WT mice.

CONCLUSION

Our results suggest that chronic tissue PAI-1 overexpression influences the early phase of the inflammatory response during endotoxemia through the control of T lymphocyte traffic.

Effect of sleep apnea syndrome on the circadian profile of cortisol in obese men

It has been hypothesized that sleep apnea syndrome (SAS) increases hypothalamic-pituitary-adrenal axis activity and, through increased cortisol levels, participates in the pathophysiology of metabolic and cardiovascular complications. We compared the circadian profiles of cortisol in obese men with [obSAS+; apnea-hypopnea index (AHI) >or= 20/h] and without SAS (obSAS-; AHI <or= 5/h). 1) Salivary cortisol (5 samples: before/30 min after dinner, 2100, upon/30 min after awakening) was measured in 15 obSAS+, 19 obSAS-, and 19 normal-weight controls (NWC). 2) Plasma cortisol (every 30 min for 24 h under highly controlled conditions and portable EEG device) was measured in 9 obSAS+, 8 obSAS-, and 10 NWC men. Visceral adipose tissue surface was measured by CT scan. In both studies, obSAS+ and obSAS- men were comparable for age, BMI, waist circumference, and waist-to-hip ratio. First, no difference was found, using ANOVA for repeated measures, between obSAS+ and obSAS- subjects for any salivary cortisol measurement. No correlation was found between salivary cortisol and AHI or nocturnal SaO(2). Similarly, obSAS+ and obSAS- men showed no difference in plasma cortisol rhythmicity: 24-h minimum, maximum, and mean, ANOVA for repeated measures, mathematical modeling of cortisol rhythm (COSINOR), and morning secretory peak. Conversely, ANOVA for repeated measures showed decreased cortisol levels in obese vs. NWC men during both the trough (2200-0130) and the peak (0600-0900) independently of SAS status. We show that SAS per se is not associated with any change of the level or of the features of salivary and plasma cortisol rhythmicity and confirm that men with visceral obesity display lower plasma cortisol levels than NWC men.

Association of plasminogen activator inhibitor (PAI)-1 (SERPINE1) SNPs with myocardial infarction, plasma PAI-1, and metabolic parameters: the HIFMECH study

OBJECTIVE

The purpose of this study was to investigate the effects of plasminogen activator inhibitor-1 (PAI-1) gene (SERPINE1) single nucleotide polymorphisms (SNPs) on the risk of myocardial infarction (MI), on PAI-1 levels, and factors related to the metabolic syndrome.

METHODS AND RESULTS

Eleven SNPs capturing the common genetic variation of the SERPINE1 gene were genotyped in the HIFMECH study. In the 510 male cases and their 543 age-matched controls, a significant gene-smoking interaction was observed. In nonsmokers, the rs7242-G allele was more frequent in cases than in controls (0.486 versus 0.382, P=0.013) whereas the haplotype derived from the rs2227631 (-844A>G)-G and rs2227683-A alleles was approximately 3-fold lower in cases than in controls (0.042 versus 0.115, P=0.006). SERPINE1 haplotypes explained 3.5% (P=0.007) of the variability of PAI-1 levels, which was attributable to the combined effects of 3 SNPs, -844A>G, rs2227666, and rs2227694. The rs6092 (Ala15Thr) and rs7242 SNPs acted additively to explain 4.4% of the variability of plasma insulin levels and 1.6% of the variability of BMI (P<10(-3) and P=0.023, respectively).

CONCLUSIONS

SERPINE1 haplotypes are mildly associated with plasma levels of PAI-1 and with the risk of MI in nonsmokers. They are also associated with insulin levels and BMI.

C3H/HeJ mice carrying a toll-like receptor 4 mutation are protected against the development of insulin resistance in white adipose tissue in response to a high-fat diet

AIMS/HYPOTHESIS

Inflammation is associated with obesity and has been implicated in the development of diabetes and atherosclerosis. During gram-negative bacterial infection, lipopolysaccharide causes an inflammatory reaction via toll-like receptor 4 (TLR4), which has an essential function in the induction of innate and adaptative immunity. Our aim was to determine what role TLR4 plays in the development of metabolic phenotypes during high-fat feeding.

MATERIALS AND METHODS

We evaluated metabolic consequences of a high-fat diet in TLR4 mutant mice (C3H/HeJ) and their respective controls.

RESULTS

TLR4 inactivation reduced food intake without significant modification of body weight, but with higher epididymal adipose tissue mass and adipocyte hypertrophy. It also attenuated the inflammatory response and increased glucose transport and the expression levels of adiponectin and lipogenic markers in white adipose tissue. In addition, TLR4 inactivation blunted insulin resistance induced by lipopolysaccharide in differentiated adipocytes. Increased feeding efficiency in TLR4 mutant mice was associated with lower mass and lower expression of uncoupling protein 1 gene in brown adipose tissue. Finally, TLR4 inactivation slowed the development of hepatic steatosis, reducing the liver triacylglycerol content and also expression levels of lipogenic and fibrosis markers.

CONCLUSIONS/INTERPRETATION

TLR4 influences white adipose tissue inflammation and insulin sensitivity, as well as liver fat storage, and is important in the regulation of metabolic phenotype during a fat-enriched diet.

Prognostic value of plasma tissue factor and tissue factor pathway inhibitor for cardiovascular death in patients with coronary artery disease: the AtheroGene study

BACKGROUND

Tissue factor (TF) and its specific inhibitor, tissue factor pathway inhibitor (TFPI), are important contributors to the initiation of the coagulation process.

OBJECTIVES

To compare plasma levels of soluble TF (sTF) and free-TFPI (f-TFPI) between patients with stable angina pectoris (SAP) and acute coronary syndrome (ACS) and to assess the impact of the two variables on long-term prognosis.

PATIENTS/METHODS

Patients with SAPs (n = 1146) and acute coronary syndrome (n = 523) from the AtheroGene study were included and followed for 2.3 years. Because of the strong impact of unfractionated heparin (UFH) on f-TFPI levels, but not on sTF levels, patients having received UFH before blood drawing were excluded from the analyses on f-TFPI (n = 226).

RESULTS

On admission, no significant differences in sTF levels were observed between SAP and ACS patients. By comparison to patients with stable angina, f-TFPI levels significantly increased in patients with acute unstable angina and further increased in patients presenting with non-ST-elevation myocardial infarction and ST-elevation myocardial infarction (P < 10(-4)). Among the 1669 individuals with a coronary artery disease, 56 died from a cardiovascular cause. In prospective analyses, high sTF levels were independently associated with an increased risk of cardiovascular death in individuals with ACS (fully adjusted hazard ratio associated with one quartile increase = 2.06; 95% confidence interval 1.24-3.45; P = 0.006) but not in those with SAP (hazard ratio = 1.07; 95% confidence interval 0.78-1.46; P = 0.67). In SAP and ACS patients, high f-TFPI levels were not independently associated with an increased risk of cardiovascular death.

CONCLUSIONS

Plasma sTF levels were predictive of cardiovascular mortality in individuals with ACS, whereas f-TFPI levels were associated with the severity of myocardial damage on admission but were not independently related to outcome.

[Acute stent thrombosis due to resistance to clopidogrel ? A case report]

The authors report the case of a 65 year old man who presented with an acute coronary syndrome without ST elevation due to acute stent thrombosis 12 hours after implantation. Recent reports in the literature suggest the role of resistance to antiplatelet drugs in acute, subacute or late stent thrombosis. This patient was included in a protocol studying the response to antiplatelet drugs in patients undergoing coronary stenting and fulfilled the criteria of resistance to clopidogrel. This clinical case illustrates the possible role of "resistance" to antiplatelet drugs in stent thromboses.

[Platelet function after a high dose bolus of tirofiban immediately after coronary angioplasty]

In the TARGET trial, the lower incidence of cardiac events at one month with abciximab compared with tirofiban was attributed to a lack of efficacy in the first hour because of suboptimal dosage. The object of this study was to confirm that high dose tirofibal is associated with over 90% platelet inhibition during the first hour and to analyse the effect of this new dosage on platelet activation. Thirty-three patients treated with clopidogrel and aspirin for an acute coronary syndrome without ST elevation were given before angioplasty a bolus of 25 microg/Kg of tirofiban injected in 3 minutes, followed by an infusion of 0.15 microg/kg/min. Blood samples were taken before the treatment (TO) and at the 45th minute (T1) to measure platelet aggregation induced by ADP, the expression of P-selection, the quantification of circulating monocyte-platelet aggregates and the phospholyration of VASP protein. The results showed that all patients had over 90% (100%) inhibition of platelet aggregation at T1. The expression of P-selection was significantly reduced (T0: 0.195 +/- 0.057 MFI; T1: 0.186 +/- 0.055 MFI, p = 0.03). There was no significant difference in the number of monocyte-platelet aggregates or in the phosphorylation of VASP. In conclusion, a bolus of 25 microg/Kg/3 min of tirofiban provides over 90% inhibition of platelet aggregation in the first hour. The initial platelet proactivator effect at this dosage was shown to have disappeared with an inhibition of platelet activation.

[Beneficial effect of a loading dose of 600 mg of clopidogrel on platelet parameters in patients admitted for acute coronary syndrome]

INTRODUCTION

Despite the beneficial effect of an aspirin-clopidogrel combination in acute coronary syndrome, the incidence of ischaemic recurrences remains significant and very probably implicates a variability in the response to anti-platelet agents.

OBJECTIVE

We sought to demonstrate the evidence for a beneficial effect, in terms of anti-platelet effect, of a higher loading dose of 600 mg of clopidogrel compared to the usual 300 mg in patients admitted to our centre with acute coronary syndrome.

MATERIALS AND METHODS

Platelet reactivity was evaluated with the ADP 10_mol test and the degree of platelet activation by the expression of P-selectin. 178 consecutive patients admitted for acute coronary syndrome received 250 mg of intravenous aspirin together with either a loading dose of 300 mg of clopidogrel (n = 104) or 600 mg (n = 74) administered 12 to 24 hours prior to coronary angiography.

RESULTS

The patients who received 600 mg of clopidogrel had an average aggregation intensity to ADP and a rate of platelet high reactivity post treatment that was significantly lower [48+20 vs 58+18, p = 0.0011 and 11 patients (15%) vs 26 patients (25%), p = 0.0003 respectively]. The degree of platelet activation evaluated with P-selectin was significantly lower in patients receiving 600mg [0.33 + 0.17 vs 0.50+0.29, p < 0.001].

CONCLUSION

Our study provides evidence for a beneficial effect of a loading dose of 600mg of clopidogrel compared to the usual 300 mg in terms of platelet reactivity and platelet activation post treatment.

Biological and genetic factors influencing plasma factor VIII levels in a healthy family population: results from the Stanislas cohort

The mechanisms underlying the variability of factor VIII (FVIII) levels are still poorly understood. The only receptor of FVIII identified so far is the lipoprotein receptor-related protein (LRP), which is thought to be involved in FVIII degradation. We aimed to characterize biological and genetic factors related to FVIII variability, focusing on coding polymorphisms of the LRP gene and polymorphisms potentially detected by molecular screening of the LRP-binding domains of the FVIII gene. Plasma FVIII coagulant activity (FVIII:C) and von Willebrand factor (VWF:Ag) antigen levels were measured in a sample of 100 healthy nuclear families (200 parents and 224 offspring). The ABO blood group and the three coding polymorphisms of the LRP gene (A217V, D2080N and C766T) were genotyped. Lipids and anthropometric factors poorly contributed to the variability of FVIII:C (<5%). A strong effect of ABO blood groups on FVIII:C levels was observed that remained significant after adjustment for VWF:Ag levels (P = 0.02). These two factors explained more than 50% of FVIII:C variability. After adjustment for VWF:Ag and ABO blood groups, a residual resemblance for FVIII:C persisted between biological relatives (rho = 0.13 +/- 0.06 between parents and offspring, rho = 0.24 +/- 0.09 between siblings) compatible with an additional genetic influence. The N allele of the LRP/D2080N polymorphism was associated with decreased levels of FVIII:C (90.4 +/- 8.7 vs. 102.2 +/- 3.5 IU/dl, P = 0.03) and VWF:Ag levels (109.1 +/- 11.2 vs. 125.4 +/- 4.4 IU/dl, P = 0.02). No polymorphism was detected in the LRP-binding domains of the FVIII gene. This study reinforces the hypothesis of a genetic influence of FVIII levels beyond the influence of VWF:Ag and ABO blood groups. The D2080N polymorphism of the LRP gene weakly contributed to the variability of FVIII:C levels in this healthy population.

Interaction between the C-260T polymorphism of the CD14 gene and the plasma IL-6 concentration on the risk of myocardial infarction: the HIFMECH study

Experimental and clinical observations suggest that innate immunity plays a major role in the pathogenesis and progression of atherosclerosis. A common C-260T polymorphism in the promoter of the CD14 gene, the trans-membrane receptor of lipopolysaccharides, has been inconsistently associated with coronary heart disease. Our objective was to evaluate the contribution of the CD14 polymorphism to the inflammatory response and to the risk of myocardial infarction (MI). We used an European case-control study, the HIFMECH study, comparing 533 men with MI and 575 sex- and age-matched controls. Associations between genotype and disease outcome, according to interleukin-6 (IL-6) and C-reactive protein (CRP) levels, were assessed using conditional logistic regression. The CD14/C-260T polymorphism was associated with plasma IL-6 levels, T/T subjects having higher plasma levels than C/C in cases but not in controls (mean+/-S.D.: 2.04+/-1.37 versus 1.70+/-1.15, p=0.01; 1.20+/-0.75 versus 1.35+/-0.88, p=0.31, respectively). Overall, the CD14/C-260T polymorphism was not associated with the risk of MI. However, in individuals with IL-6 plasma levels in the highest tertile, T allele carriers had a higher risk of MI than C/C (OR: 1.85; CI 95 1.05-3.25). IL-6 increased the risk of MI in carriers of the T allele (OR for first versus third IL-6 tertile: 4.02; CI 95 2.24-7.21), but not in C/C (OR: 0.75; CI 95 0.32-1.74, p=0.004 for interaction). The data indicate a role for CD14/C-260T in MI. The risk mediated by the polymorphism is highly dependent on IL-6 plasma levels.

Contribution of PAI-1 in cardiovascular pathology

Plasminogen activator inhibitor-1 (PAI-1), is a serpin whose major function is to negate plasminogen activation and impair fibrinolysis. It occurs in plasma and tissues. Studies in genetically modified mice indicate that PAI-1 might be involved in thrombosis, vascular healing and atherosclerosis although contradictory findings have been obtained in the latter two processes. Differences between results depend on the types and the lengths of the models and underline the fact that besides its role in regulating fibrinolysis, PAI-1 plays a role in several cellular processes independent of plasminogen activation. In patients, high plasma PAI-1 levels worsen the prognosis of myocardial infarction in the acute phase and have been considered as a risk factor for coronary heart disease. The predictive capacity of PAI-1 is mainly related to several metabolic covariates which constitute the metabolic syndrome (MS). This syndrome is associated with increased cardiovascular morbidity and mortality and is becoming one of the major health problems as its prevalence is growing rapidly. Accelerated atherothrombotic process in the MS is attributed not only to metabolic abnormalities but also to a specific inflammatory state which leads to increased plasma PAI-1 levels. Modifying PAI-1 expression by PAI-1 inhibitors may open a new field of research and may reveal the true role of PAI-1 in atherosclerotic and insulin resistance processes.