Impact of Molecular Biology in Diagnosis, Prognosis, and Therapeutic Management of BCR::ABL1-Negative Myeloproliferative Neoplasm

BCR::ABL1-negative myeloproliferative neoplasms (MPNs) include three major subgroups-polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF)-which are characterized by aberrant hematopoietic proliferation with an increased risk of leukemic transformation. Besides the driver mutations, which are JAK2, CALR, and MPL, more than twenty additional mutations have been identified through the use of next-generation sequencing (NGS), which can be involved with pathways that regulate epigenetic modifications, RNA splicing, or DNA repair. The aim of this short review is to highlight the impact of molecular biology on the diagnosis, prognosis, and therapeutic management of patients with PV, ET, and PMF.

The aminosterol Claramine inhibits β-secretase 1-mediated insulin receptor cleavage

The cleavage of the insulin receptor by β-secretase 1 (BACE1) in the liver increases during diabetes, which contributes to reduce insulin receptor levels and impair insulin signaling. However, the precise signaling events that lead to this increased cleavage are unclear. We showed that BACE1 cleaves the insulin receptor in the early secretory pathway. Indeed, coimmunoprecipitation experiments reveal the interaction of the proforms of the two proteins. Moreover, fragments of insulin receptor are detected in the early secretory pathway and a mutated form of BACE1 that retains its prodomain cleaves an early secretory pathway-resident form of the insulin receptor. We showed that BACE1 proform levels are regulated by proteasome and/or lysosome-dependent degradation systems whose efficiencies are dependent on the O-GlcNacylation process. Our results showed that enhanced O-GlcNacylation reduces the efficiency of intracellular protein degradation systems, leading to the accumulation of the proform of BACE1 in the early secretory pathway where it cleaves the precursor of the insulin receptor. All these dysregulations are found in the livers of diabetic mice. In addition, we performed a screen of molecules according to their ability to increase levels of the insulin receptor at the surface of BACE1-overexpressing cells. This approach identified the aminosterol Claramine, which accelerated intracellular trafficking of the proform of BACE1 and increased autophagy. Both of these effects likely contribute to the reduced amount of the proform of BACE1 in the early secretory pathway, thereby reducing insulin receptor cleavage. These newly described properties of Claramine are consistent with its insulin sensitizing effect.

Ultrasound arterial anomalies in patients exposed to nilotinib therapy for chronic myeloid leukemia

INTRODUCTION

Patients exposed to nilotinib for chronic myeloid leukemia (CML) appear to be at risk of arterial complication. The prevalence and aspect of ultrasound asymptomatic arterial lesions are unknown.

OBJECTIVE

To describe prevalence and characteristics of ultrasound arterial anomalies in patients treated with nilotinib for CML.

METHODS

Patients treated with nilotinib from 2006 to 2015 in the department of the Paoli-Calmettes Institute, Marseille, were included retrospectively. A vascular ultrasound screening was carried out from 2010. The arterial lesions at the first examination were described: plaque and its echogenicity, stenosis or occlusion. A vascular arterial anomaly (VAA) was defined by the presence of a clinical and/or ultrasound anomaly. Patients with or without VAA at initial vascular examination were compared using bivariate and multivariate analysis.

RESULTS

74 patients were included (51.4% men, mean age 54.5 years); 25 patients had ultrasound arterial anomalies (33.8%). Carotid bulb was the most involved territory (44%). Arterial anomalies were: 88% plaques, 44%>50% stenosis and 12% occlusion. 72.7% plaques were echolucent or hypoechogenic. A VAA was present in 25 patients with initial vascular evaluation (33.8%). Patients with VAA at baseline were significantly older (64.9 vs 49.3, P<0.001), older at nilotinib initiation (60.8 vs 46.5, P<0.001), with more arterial hypertension (40% vs 12.2%, P=0.01), with more cardiovascular risk factors (P=0.03). In patient with no cardiovascular risk factor 12.5% had VAA (n=24).

CONCLUSION

Nilotinib seems to be associated to arterial lesions of unstable lipid-like appearance. The most involved arterial territory was the carotid bulb and the most common lesion was echolucent or hypoechogenic plaque. VAA can occur in patients without cardiovascular risk factors. This result encourages us to systematically screen and follow all patients exposed to nilotinib even those without cardiovascular risk factors.

Descriptive study of the general practitioners' perception of direct oral anticoagulants and the risk of genital bleeding in women of childbearing age

AIM OF THE STUDY AND PATIENTS

Direct oral anticoagulants (DOA) tend to replace antivitamins K (VKA). The incidence of major and minor hemorrhages is higher in women, a difference potentially linked to genital hemorrhages. The objective is to assess the practices and perception of general practitioners of the use of oral anticoagulant therapy in women of childbearing age.

MATERIALS AND METHODS

Descriptive, observational, transversal and monocentric study. An 11-items questionnaire was sent to 900 randomized general practitioners, assessing the type of patient, the type of anticoagulant prescribed, the management of genital bleeding, and the assessment of the quality of life of anticoagulated patients.

RESULTS

DOA were the most prescribed anticoagulants. Genital hemorrhage was the second leading cause of minor hemorrhage. Most doctors (60.6%) believed they were due to VKAs. 25% reported an alteration in the quality of life of patients following these genital hemorrhages and 47.5% addressed this subject in consultation.

CONCLUSION

Our study suggests that, according to the general practitioners interviewed, genital hemorrhage is more frequent on VKA than on DOA in women of reproductive age, which is contradictory with the data in the literature. The probably taboo subject is rarely mentioned in consultation and is responsible for a deterioration in the quality of life in these young patients. No recommendation exists on the management of this type of genital hemorrhage in these women. An algorithm is proposed for their management.

[Bilateral adrenal hemorrhage under apixaban in primary antiphospholipid syndrome]

INTRODUCTION

Adrenal hemorrhage is a classical but rare complication of antiphospholipid syndrome, revealing diagnosis in one third of the cases. Anti-vitamin K therapy is the standard treatment but direct oral anticoagulants are discussed as an alternative. In the latest recommendations, it is advised not to use direct oral anticoagulants in the setting of antiphospholipid syndrome.

CASE REPORT

We present a case of bilateral adrenal hemorrhage revealing primary antiphospholipid syndrome with triple positive antibody profile, in a 47-year-old man treated by apixaban for previous venous thromboembolism.

CONCLUSION

To our knowledge, it is the first case of adrenal hemorrhage occurring during apixaban treatment in a patient with antiphospholipid syndrome. This case illustrates the inefficacy of direct oral anticoagulants to prevent thrombotic events in antiphospholipid syndrome, in accordance with the latest recommendations.

[Evaluation of an "Emergency Thrombosis" care system in a university-hospital department of general emergencies]

GOAL

Describe the use of diagnostic, prognostic and therapeutic algorithms for venous thromboembolism (VTE), derived from the 2014 European guidelines, in a teaching hospital's emergencies department and compare two groups: the 2015 group "without a care path" and the 2017 group "with a care path".

METHOD

Comparative and retrospective study of the characteristics of emergencies department patients admitted for VTE from January to June 2015 for the 2015 group and from January to June 2017 for the 2017 group.

RESULTS

Seventy-nine patients were included in the 2015 group and 62 patients in the 2017 group. In 24% of cases a clinical probability rule was calculated in the 2017 group (vs. no score in 2015, P<0.05). In the 2015 group, 10% of patients did not have a D-Dimer measurement in case of low clinical probability (vs. 0% in 2017, P<0.05). For both groups, the severity score sPESI was not noted in the medical record. All patients with pulmonary embolism were hospitalized in both groups. A total of 36% of patients with deep vein thrombosis (DVT) were hospitalized in the 2015 group (vs. none in 2017, P<0.05). A total of 52.5% of patients were treated with direct oral anticoagulants (DOAS) in the 2017 group vs. 32.5% in the 2015 group (P<0.05). In 18% of cases DOAS were prescribed by emergency physicians in the 2017 group vs. 2.5% in the 2015 group (P<0.05). Mean hospital stay was 7.4 days in the 2017 group and 9.4 days in the 2015 group (P<0.05).

CONCLUSION

We observed a change in clinical practices and prescriptions after the establishment of an "Emergency Thrombosis" care system. Indeed, improvement in the calculation of the clinical probability score, increase in the outpatient management of DVT, increase in prescribing DOAS and reducing the length of hospital stay were the main revisions. The implementation of standardized digitally calculated clinical and prognostic probability scores would optimize this care path, as well as allow a better distribution of the post-emergency consultations created for outpatients.

Initial strides for invent-VTE: Towards global collaboration to accelerate clinical research in venous thromboembolism

Venous thromboembolism (VTE) represents a major global burden of disease and requires collaborative efforts to conduct large, high-quality investigator-initiated and academically sponsored studies addressing the most relevant clinical questions. Owing to increasing regulatory requirements, the highly competitive nature of peer-reviewed funding and costs associated with conducting large, multinational clinical trials, completing practice-changing research constitutes a growing challenge for clinical investigators. As clinical trialists interested in VTE, we founded INVENT (International Network of Venous Thromboembolism Clinical Research Networks) in an effort to promote and accelerate patient-oriented, investigator-initiated, international collaborative research, to identify, prioritize and answer key clinical research questions for patients with VTE. We report on our activities to formalize the INVENT network and our accomplishments in our first year.

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.

Relationship of Plasminogen Activator Inhibitor-1 Levels following Thrombolytic Therapy with rt-PA as Compared to Streptokinase and Patency of Infarct Related Coronary Artery

Background: Type 1 plasminogen activator inhibitor (PAI-1) is considered to be risk factor for acute myocardial infarction (AMI). A rebound of circulating PAI-1 has been reported after rt-PA administration. We investigated the relationships between PAI-1 levels before and after thrombolytic therapy with streptokinase (SK) as compared to rt-PA and the patency of infarct-related arteries.

Methods and Results: Fifty five consecutive patients with acute MI were randomized to strep-tokinase or rt-PA. The plasma PAI-1 levels were studied before and serially within 24 h after thrombolytic administration. Vessel patency was assessed by an angiogram at 5 ± 1days. The PAI-1 levels increased significantly with both rt-PA and SK as shown by the levels obtained from a control group of 10 patients treated with coronary angioplasty alone. However, the area under the PAI-1 curve was significantly higher with SK than with rt-PA (p <0.01) and the plasma PAI-1 levels peaked later with SK than with rt-PA (18 h versus 3 h respectively). Conversely to PAI-1 levels on admission, the PAI-1 levels after thrombolysis were related to vessel patency. Plasma PAI-1 levels 6 and 18 h after SK therapy and the area under the PAI-1 curve were significantly higher in patients with occluded arteries (p <0.002, p <0.04 and p <0.05 respectively).The same tendency was observed in the t-PA group without reaching significance.

Conclusions: This study showed that the PAI-1 level increase is more pronounced after SK treatment than after t-PA treatment. There is a relationship between increased PAI-1 levels after thrombolytic therapy and poor patency. Therapeutic approaches aimed at quenching PAI-1 activity after thrombolysis might be of interest to improve the efficacy of thrombolytic therapy for acute myocardial infarction.

Association between TAFI antigen and Ala147Thr polymorphism of the TAFI gene and the angina pectoris incidence

Thrombin activatable fibrinolysis inhibitor (TAFI), a recently described inhibitor of fibrinolysis, has been hypothesized as playing a role in atherothrombosis. However, the evidence from retrospective studies, which have evaluated the role of TAFI in vascular risk, is conflicting.

In a prospective cohort (the PRIME Study) of nearly 10 000 apparently healthy men recruited in France (Lille, Strasbourg, Toulouse) and Northern Ireland (Belfast), we measured baseline plasma concentration of TAFI antigen among 143 participants (81 from France and 62 from Ireland) who subsequently developed angina pectoris and among 286 age-matched participants who remained free of disease during the 5 years of follow-up. Genotyping of the Ala147Thr polymorphism located in the TAFI gene was performed using an allele specific PCR. In France, mean levels of TAFI were significantly higher at baseline among men who subsequently developed angina pectoris compared with their control subjects (119 versus 107 %; p = 0.02). The risk of future angina pectoris increased with increasing tertiles of TAFI (p = 0.02), such that men in the highest tertile at study entry had a 5-fold higher relative risk than those in the lowest tertile (95% confidence interval, 1.38 to 18.58) after controlling for the conventional cardiovascular risk factors. No such difference was observed in Northern Ireland. In France, Thr/Thr carriers of the Ala147Thr polymorphism were significantly more frequent in cases than in controls (p = 0.01) leading to a relative risk of angina pectoris of 2.7 (95%CI 1.2-5.8).

Increase in plasma TAFI antigen levels is a risk factor for angina pectoris in France. Genotyping for the Ala147Thr polymorphism seems to be a reliable tool to assess the risk mediated by TAFI.

Activation of Plasminogen Activator Inhibitor-1 Synthesis by Phorbol Esters in Human Promyelocyte HL-60

HL-60 cells treated by PMA develop the monocyte adherent pheno-type and synthesize plasminogen activator inhibitor type-1 (PAI-1). We focused our study on the identification of the PMA-activated protein kinase C (PKC) isoform and its downstream transduction pathway activating PAI-1 synthesis. Acquisition of the monocytic phenotype was evidenced by cell adherence (90-95%) and a sharp increase of CD 36 and receptor for urokinase plasminogen activator (uPAR) surface expression. Ro 31-8220, a specific inhibitor of PKC, prevented PMA-induced PAI-1 synthesis (mRNA and protein levels) and cell adhesion. To identify the PKC isoform, we took advantage of the HL-525 cell line, an HL-60 cell variant deficient in PKCβ gene expression. This defect prevents PMA to induce the differentiation process. HL-525 stimulated by PMA did not synthesize PAI-1 nor become adherent. However, in HL-525 cells either pretreated by retinoic acid that reinduces PKCβ gene expression or transfected with PKCβ cDNA, PMA significantly activated PAI-1 synthesis and adhesion of cells. Immunoblotting of active Mitogen Activated Protein Kinase (MAPK) p42/p44 in HL-60 cells showed a preferential and sustained activation of the p42 isoform by PMA over the p44 isoform. Ro 31-8220 significantly attenuated this activation. PD 098059 and U0126, both highly specific MEK inhibitors, efficiently prevented PMA-induced PAI-1 synthesis (mRNA and protein levels) and cell adhesion whereas SB203580, a specific inhibitor of stress-activated MAPK p38, did not. Results obtained from HL-60 and HL-525 cells indicate that the PMA-activated transduction pathway of uPAR expression involves a PKC isoform other than PKCβ.

In conclusion, we propose that the pathway PKCβ-MEK-MAPK p42 is a potential linear route for PAI-1 synthesis leading to morphological changes and adherence linked to PMA-induced differentiation in HL-60 cells.

Polymorphism A36G of the tumor necrosis factor receptor 1 gene is associated with PAI-1 levels in obese women

The tumor necrosis factor (TNF) pathway may be implicated in etiopathogenesis of PAI-1 overexpression during obesity. The aim of this study was to investigate the influence of polymorphismA36G of the TNF receptor 1 (TNFRSF1A +36A/G) on plasma concentrations of PAI-1 in 163 obese (31 with the metabolic syndrome, MetS) and 150 lean, healthy women. Genotypic and allele frequencies did not significantly differ between obese and lean subjects. TNFRSF1A genotypes were significantly associated with sTNFR1 plasma levels in obese women only (p<0.01); TNFRSF1A +36G/G obese carriers exhibited higher sTNFR1 and PAI-1 levels than A carriers (p<0.01 and p<0.05, respectively). In obese women, the presence of the MetS significantly potentiated the elevation of sTNFR1 and PAI-1 levels observed in the TNFRSF1A+36G/G carriers. Our results suggest that association between TNFRSF1A +36G/G genotype and the MetS renders obese women more prone to activation of the TNF pathway reflected by high circulating sTNFR1 and PAI-1 levels.

Is platelet inhibition correlated with time from last intake on P2Y12 blockers after an acute coronary syndrome? A pilot study

Delay from the last intake of drug could be an important and unexplored variable in the biological response to antiplatelet agents after acute coronary syndrome (ACS) discharge. The objective was to define the impact of the delay from P2Y12 blocker intake on the platelet inhibition level. We compared ticagrelor-, prasugrel-, and clopidogrel-treated patients. All consecutive patients, who had been addressed between 2013 and 2014 for ACS, treated with aspirin and a P2Y12 blocker as maintenance dose, were eligible. One month after discharge, blood sample and a questionnaire were proposed to the patient by a nurse blinded to the protocol. On this questionnaire, three questions about name of the drug, regularity of the intakes, and hour of the last intake were collected. The response to antiplatelet therapy was assessed using platelet reactivity index vasodilator-stimulated phosphoprotein (PRI VASP) and % of adenosine-5'-diphosphate-induced aggregation (%ADP).The primary objective of this study was to evaluate the correlation between platelet inhibition and delay from drug intake. We enrolled 474 ACS treated with clopidogrel 75 mg in 182 cases (38% patients), prasugrel in 190 cases (40%), or ticagrelor in 102 patients (22%). We observed a significant correlation between delay from intake and PRI VASP and %ADP for ticagrelor (r = 0.25, p = 0.01; r = 0.21, p = 0.03; respectively). On clopidogrel (r = 0.09, p = 0.24; r = 0.02, p = 0.80; respectively) and prasugrel (r = 0.02, p = 0.82; r = 0.11, p = 0.12 respectively), no correlation exists. In conclusion, ticagrelor, unlike thienopyridines, is associated with a significant correlation between delay from the last intake and platelet inhibition.

[Antiphospholipids antibodies and hemodialysis: a frequent association linked to arteriovenous fistula thrombosis]

Antiphospholipid antibodies (APL) are a heterogeneous family of auto-antibodies that recognize phospholipoproteins bound antigenic epitopes. APL prevalence in patients on chronic hemodialysis ranges from 11 to 37% in the literature. The association of APL with hemodialysis vascular access (VA) thrombosis has already been reported in small studies. In this single center and retrospective study, we defined the APL prevalence and APL risk factors in a large cohort of 192 hemodialysis patients. The association between history of VA thrombosis and APL presence was also analyzed. At least one type of APL was found in 38 patients (19.8%) of which 74% (n=28) had only lupus anticoagulant. Median age of APL positive patients was 68.1years vs. 71.3years in APL negative patients (P=0.02). Smoking history was associated with APL presence: 35.5% of APL positive patients had a smoking history vs only 18.3% of APL negative patients (P=0.04). The multivariate analysis showed an association between the history of VA thrombosis and patient age (HR [IC 95%]=1.04 [1.02-1.06]; P=0.001) or APL presence (HR [IC 95%]=3.03 [1.69-4.42]; P<10(-3)). In conclusion, the prevalence of APL in hemodialysis patients remains high despite hemodialysis techniques improvement: hemodiafiltration, biocompatibility improvements, ultrapure dialysis water. We report that a younger age and past history of smoking are associated with an increased risk of APL presence. The presence of APL, especially lupus anticoagulant, is associated to VA thrombosis in hemodialysis patients.

Safety and effectiveness of the association ezetimibe-statin (E-S) versus high dose rosuvastatin after acute coronary syndrome: the SAFE-ES study

BACKGROUND

Statin therapy is a cornerstone therapy for secondary prevention after acute coronary syndrome (ACS). However, the use of these drugs can be limited by side effects, mainly muscular pain. Ezetimibe is a newer lipid-lowering agent, with fewer side effects.

AIMS

The present study was designed to compare a commercially available association of ezetimibe and simvastatin (E-S) to high dose Rosuvastatin on cholesterol and muscular enzyme levels and occurrence of muscular pain.

METHODS

All consecutive ACS statin-naïve patients with LDL cholesterol (LDL-C)>100mg/dL randomly received either high dose statin (Rosuvastatin 20mg) or E-S 10/40-mg. All patients had one-month follow-up with biological testing and clinical examination. We compared the two groups on the biological efficiency and incidence of muscular pain.

RESULTS

One hundred and twenty-eight patients were randomized; 64 received E-S and 64 Rosuvastatin. In the two groups, the lowering of LDL-C level (Δ=51%) at one month was significant (P<0.01) without any difference in the rate of lowering on LDL-C or HDL-C suggesting that E-S is as effective as high dose Rosuvastatin (P=0.77 and P=0.99). The rate of patients reaching the objective of LDL-C<100mg/dL (45%) and LDL-C<70mg/dL (51%) was not different in the two clusters (P=0.65). Incidence of muscular pain was 15% higher in patients treated with Rosuvastatin (P=0.01) without any difference on CPK level (P=0.6).

CONCLUSION

Using an association of E-S in an effective alternative strategy to high dose Rosuvastatin with a lower incidence of muscular pain, which might impact adherence to medication after ACS.

[DVT and combined oral contraceptives: update of the pluridisciplinary CNGOF-FNCGM-GEHT-SFMV group]

Thrombotic risk among combined oral contraceptives (COC) users has recently been debated following a court action initiated by a patient. Recent epidemiological data, as well as accumulating biological data underlying these data, have led French Health authorities to modify COC prescription and reimbursement modalities. A short synthesis is proposed by a multidisciplinary group of experts from four French societies (CGOF, FNCGM, GHT, and SFMV).

TFPI resistance related to inherited or acquired protein S deficiency

BACKGROUND

Protein S (PS) is an essential component of the protein C pathway and PS deficiency can explain a poor response to activated protein C. It has recently been shown that PS also acts as a cofactor of Tissue Factor Pathway Inhibitor (TFPI).

OBJECTIVES

In the present study, we investigated whether PS deficiency could be responsible for a poor response to TFPI.

PATIENTS/METHODS

Thirty-one patients with inherited PS deficiency, seven pregnant women and 36 controls were enrolled in the study. We measured the plasma response to added TFPI using a two-step diluted prothrombin time (dPT) assay. The response of the different plasmas to the anticoagulant activity of TFPI was expressed as TFPI Normalised Ratio (TFPI NR).

RESULTS

The median TFPI NR was statistically significantly lower in patients with inherited PS deficiency (0.5) than in controls (1.0) (p<0.0001). It was statistically significantly lower in patients with type I inherited PS deficiency (0.47) compared to patients with type III inherited PS deficiency (0.58) (p=0.018). In contrast, it did not differ between patients with and without thrombosis. Median TFPI NR values were statistically significantly lower during pregnancy (0.54) than 3 months after delivery (0.71) (p=0.016). TFPI NR values correlated well with PS activity values (R(2)=0.681) whatever the nature of the PS deficiency.

CONCLUSIONS

Our findings confirm that PS deficiency results in a poor anticoagulant response to TFPI, demonstrating again the cofactor role of PS in TFPI activity.

Systemic chemokine levels, coronary heart disease, and ischemic stroke events: the PRIME study

OBJECTIVES

To quantify the association between systemic levels of the chemokine regulated on activation normal T-cell expressed and secreted (RANTES/CCL5), interferon-γ-inducible protein-10 (IP-10/CXCL10), monocyte chemoattractant protein-1 (MCP-1/CCL2), and eotaxin-1 (CCL11) with future coronary heart disease (CHD) and ischemic stroke events and to assess their usefulness for CHD and ischemic stroke risk prediction in the PRIME Study.

METHODS

After 10 years of follow-up of 9,771 men, 2 nested case-control studies were built including 621 first CHD events and 1,242 matched controls and 95 first ischemic stroke events and 190 matched controls. Standardized hazard ratios (HRs) for each log-transformed chemokine were estimated by conditional logistic regression.

RESULTS

None of the 4 chemokines were independent predictors of CHD, either with respect to stable angina or to acute coronary syndrome. Conversely, RANTES (HR = 1.70; 95% confidence interval [CI] 1.05-2.74), IP-10 (HR = 1.53; 95% CI 1.06-2.20), and eotaxin-1 (HR = 1.59; 95% CI 1.02-2.46), but not MCP-1 (HR = 0.99; 95% CI 0.68-1.46), were associated with ischemic stroke independently of traditional cardiovascular risk factors, hs-CRP, and fibrinogen. When the first 3 chemokines were included in the same multivariate model, RANTES and IP-10 remained predictive of ischemic stroke. Their addition to a traditional risk factor model predicting ischemic stroke substantially improved the C-statistic from 0.6756 to 0.7425 (p = 0.004).

CONCLUSIONS

In asymptomatic men, higher systemic levels of RANTES and IP-10 are independent predictors of ischemic stroke but not of CHD events. RANTES and IP-10 may improve the accuracy of ischemic stroke risk prediction over traditional risk factors.

Effects of insulin-like growth factor 1 in preventing acute coronary syndromes: the PRIME study

OBJECTIVE

Insulin-like growth factor-1 (IGF-1) has been associated with cardiovascular risk factors and atherosclerosis. The aim of the present study was to evaluate the prognostic value of IGF-1 concentrations with respect to occurrence of well-defined coronary syndromes.

METHODS

The PRIME study is a prospective cohort having included 10,600 subjects from Northern Ireland and France. Detailed information on cardiovascular risk factors, socioeconomic and behavioural variables were collected and a cardiologic examination was performed. At 5-year follow-up, 317 incident cases of coronary events were recorded according to strict protocols. They were matched to 634 age- and centre-paired controls from the same cohort, free of coronary disease. Baseline IGF-1 concentrations were measured, together with variables of lipid and glucose metabolism and markers of vascular and systemic inflammation.

RESULTS

Baseline IGF-1 concentration was lower in subjects developing an acute coronary syndrome than in unaffected controls. IGF-1 levels correlated negatively with age, waist circumference, tobacco consumption and markers of inflammation. Subjects in the highest quartile of IGF-1 distribution had a 55% reduction in the relative risk of developing myocardial infarction and a 45% decrease for all-combined acute coronary syndromes. A similar trend, although non-significant, was noted for angina pectoris. Multiple adjustments on classical risk factors and inflammation markers did not affect IGF-1 results. Elevated levels of both IGF-1 and apo A-I conferred a significantly greater risk reduction than either one alone. However, interaction between the two markers was not significant.

CONCLUSION

Like HDL markers, high levels of IGF-1 confer protection against coronary artery disease.

C-reactive protein, interleukin 6, fibrinogen and risk of sudden death in European middle-aged men: the PRIME study

OBJECTIVE

To examine prospectively the association of high-sensitivity C-reactive protein, interleukin 6, and fibrinogen with sudden death in asymptomatic European men.

METHODS AND RESULTS

Among the 9771 men from the Etude PRospective de l'Infarctus du Myocarde (PRIME) Study, 664 had a first coronary heart disease over 10 years, including 50 sudden deaths, 34 nonsudden coronary deaths, and 580 nonfatal coronary heart disease events. For each outcome, 2 matched controls, who were free of coronary heart disease at the index date, were randomly selected from the initial cohort (nested case control study design). There was a 3-fold increased risk (95% CI, 1.20 to 7.81) of sudden death between the upper and the lower third of interleukin 6 after adjustment for baseline confounders in conditional logistic regression analysis. Neither high-sensitivity C-reactive protein (hazard ratio(third versus first tertile)=1.27; 95% CI, 0.51 to 3.17) nor fibrinogen (hazard ratio(third versus first tertile)=1.90; 95% CI, 0.76 to 4.75) was associated with sudden death. For comparison, there was a 6-fold increased risk of nonsudden coronary death from the highest compared with the lowest tertile of fibrinogen and a trend toward an association with higher C-reactive protein and higher interleukin 6. All 3 inflammatory biomarkers were moderately, but significantly, associated with nonfatal coronary heart disease.

CONCLUSIONS

Interleukin 6, but not high-sensitivity C-reactive protein or fibrinogen, is an independent predictor of sudden death in asymptomatic European men.

On the use of phylogeny-based tests to detect association between quantitative traits and haplotypes

With the increasing availability of genetic data, several SNPs in a candidate gene can be combined into haplotypes to test for association with a quantitative trait. When the number of SNPs increases, the number of haplotypes can become very large and there is a need to group them together. The use of the phylogenetic relationships between haplotypes provides a natural and efficient way of grouping. Moreover, it allows us to identify disease or quantitative trait-related loci. In this article, we describe ALTree-q, a phylogeny-based approach to test for association between quantitative traits and haplotypes and to identify putative quantitative trait nucleotides (QTN). This study focuses on ALTree-q association test which is based on one-way analyses of variance (ANOVA) performed at the different levels of the tree. The statistical properties (type-one error and power rates) were estimated through simulations under different genetic models and were compared to another phylogeny-based test, TreeScan, (Templeton, 2005) and to a haplotypic omnibus test consisting in a one-way ANOVA between all haplotypes. For dominant and additive models ALTree-q is usually the most powerful test whereas TreeScan performs better under a recessive model. However, power depends strongly on the recurrence rate of the QTN, on the QTN allele frequency, and on the linkage disequilibrium between the QTN and other markers. An application of the method on Thrombin Activatable Fibronolysis Inhibitor Antigen levels in European and African samples confirms a possible association with polymorphisms of the CPB2 gene and identifies several QTNs.

[The two sides of ADAM17 in inflammation: implications in atherosclerosis and obesity]

ADAM17 was initially characterized as the TNF Alpha Converting Enzyme (TACE) and, until now, has been the most studied member of the ADAM family. It is a type I transmembrane metalloproteinase involved in the shedding of the extracellular domain of several transmembrane proteins (at least 40) such as cytokines, growth factors, receptors or adhesion molecules. As a consequence, depending on the transmembrane molecule cleaved, one may expect possible opposite effects of ADAM17 activity on inflammation (e.g. TNF and its receptors). The role of ADAM17 in regulating inflammatory cellular processes is clearly demonstrated in cells deficient in active ADAM17 or expressing substrates mutated for the ADAM17 cleavage site. As ADAM17-deficient mice died at birth, mice overexpressing the mutated uncleavable form of some substrates and recently conditional knock-out of ADAM17 are used to approach in vivo the role of this metalloprotease in regulating inflammation. Arguments are provided that ADAM17 plays a role in atherosclerosis, in adipose tissue metabolism, insulin resistance and diabetes. The multitude of substrates cleaved by ADAM17 makes this enzyme an attractive candidate to study its role in inflammation-driven pathologies.

Polymorphism A36G of the tumor necrosis factor receptor 1 gene is associated with PAI-1 levels in obese women

The tumor necrosis factor (TNF) pathway may be implicated in etiopathogenesis of PAI-1 overexpression during obesity. The aim of this study was to investigate the influence of polymorphism A36G of the TNF receptor 1 (TNFRSF1A +36A/G) on plasma concentrations of PAI-1 in 163 obese (31 with the metabolic syndrome, MetS) and 150 lean, healthy women. Genotypic and allele frequencies did not significantly differ between obese and lean subjects. TNFRSF1A genotypes were significantly associated with sTNFR1 plasma levels in obese women only (p < 0.01); TNFRSF1A +36G/G obese carriers exhibited higher sTNFR1 and PAI-1 levels than A carriers (p < 0.01 and p < 0.05, respectively). In obese women, the presence of the MetS significantly potentiated the elevation of sTNFR1 and PAI-1 levels observed in the TNFRSF1A + 36G/G carriers. Our results suggest that association between TNFRSF1A +36G/G genotype and the MetS renders obese women more prone to activation of the TNF pathway reflected by high circulating sTNFR1 and PAI-1 levels.

Predictive factors for thrombosis and major bleeding in an observational study in 181 patients with heparin-induced thrombocytopenia treated with lepirudin

The antithrombotic efficacy of lepirudin in patients with heparin-induced thrombocytopenia (HIT) is compromised by an increased risk for bleeding. A retrospective observational analysis in 181 patients (median age, 67 years) with confirmed HIT treated in routine practice with lepirudin was performed to identify predictive factors for thrombotic and bleeding complications. Lepirudin was administered at a mean (± SD) dose of 0.06 ± 0.04 mg/kg/h (compared with a recommended initial dose of 0.15 mg/kg/h). Mean activated partial thromboplastin time was greater than 1.5 times baseline value in 99.4% of patients. Median treatment duration was 7.7 days. Until discharge from the hospital, 13.8% and 20.4% of patients experienced a thrombotic or a major bleeding event, respectively. On multivariate analysis, mean lepirudin dose was not a significant predictive factor for thrombosis. In contrast, mean lepirudin dose greater than 0.07 mg/kg/h, long duration of lepirudin treatment, and moderate to severe renal impairment were significant positive factors for major bleeding. Overall, these results suggest that the recommended dose of lepirudin in patients with HIT is too high; the use of reduced doses may be safer with regard to bleeding risk and does not compromise antithrombotic efficacy.

Exclusive expression of transmembrane TNF-alpha in mice reduces the inflammatory response in early lipid lesions of aortic sinus

We investigated the effect of transmembrane form of tumor necrosis factor-alpha (TNF) on atherosclerosis in mice. We compared the development of early atherosclerotic lesions in the aortic sinus of (1) TNF-deficient mice that express only a non-cleavable transmembrane form of TNF (tmTNF), (2) wild-type (WT) C57BL/6 mice, and (3) TNF-deficient mice (TNF(-/-)). All mice were fed an atherogenic diet for 20 weeks. Lipid deposition was the most prominent in WT mice (25030 +/- 5693 microm2), tended to be lower in tmTNF mice (13640+/- 2190 microm2, P > 0.05 versus WT mice) and rare in TNF(-/-) mice (1408 +/- 513 microm2, P < 0.05 versus tmTNF and P < 0.01 versus WT). Macrophage accumulation was five-fold lower (P < 0.05) in tmTNF than in WT mice. In addition, the alpha-actin immuno-reactivity of medial smooth muscle cells remained intact in tmTNF mice but not in WT mice. In WT mice, the plasma lipid profile was significantly more atherogenic than that of TNF(-/-) mice (P < 0.05), but not significantly different from that of tmTNF mice (P > 0.05). These results indicated that in contrast to TNF(-/-) mice, mice expressing exclusively tmTNF were not completely protected from early atherosclerotic lesion formation, although their lesions have a less inflammatory state than those of WT mice, which underlines the stronger proinflammatory potential of soluble TNF.

Plasma PAI-1 levels are more strongly related to liver steatosis than to adipose tissue accumulation

OBJECTIVE

Because obesity and insulin resistance (IR) are strongly associated with liver steatosis (LS), we investigated the relation between the degree of LS and plasminogen activator inhibitor-1 (PAI-1) in ob/ob mice, in C57/BL6 mice with alcoholic LS, and in severely obese humans.

METHODS AND RESULTS

In both mouse models, plasma PAI-1 levels were associated with PAI-1 expression in the liver and with the degree of LS. Liver PAI-1 antigen was associated with the tumor necrosis factor receptor-II (TNFRII) antigen, whereas association with TNF antigen content was found in ob/ob mice only. No significant correlation between plasma PAI-1 and PAI-1 expression in adipose tissue of ob/ob mice was observed. Furthermore, the relation between plasma PAI-1 levels and body weight was positive in ob/ob mice but negative in C57/BL6 mice (both P<0.001). In humans, PAI-1 levels were correlated with the degree of LS, and 26% of plasma PAI-1 activity was independently explained by LS and serum insulin levels.

CONCLUSIONS

Plasma PAI-1 levels are more closely related to fat accumulation and PAI-1 expression in the liver than in adipose tissue. In steatotic liver, PAI-1 antigen content is associated with those of TNF and TNFRII. Therefore, we suggest that TNF pathway dysregulation in LS could be involved in increased plasma PAI-1 in obesity with IR.

Nutritionally induced obesity is attenuated in transgenic mice overexpressing plasminogen activator inhibitor-1

OBJECTIVE

The objective of this study was to investigate the role of plasminogen activator inhibitor-1 (PAI-1) in adipose tissue development in vivo.

METHODS AND RESULTS

Transgenic (Tg) mice overexpressing murine PAI-1 under control of the adipocyte promoter aP2 and wild-type (WT) controls were kept on standard food (SFD) or on high-fat diet (HFD) for 15 weeks. The body weight and the weight of the isolated subcutaneous and gonadal fat deposits of the Tg mice kept on the HFD were significantly lower than those of the WT mice. The number of adipocytes in the adipose tissue was similar for Tg and WT mice on the HFD, but adipocyte hypotrophy and a significantly lower ratio of stroma cells/adipocytes were observed in the Tg mice. A significant negative correlation (P<0.01) was observed between expression of preadipocyte factor-1, which blocks adipocyte differentiation, and adipose tissue weight. Fasting insulin and total cholesterol levels on the HFD were lower in Tg than in WT mice.

CONCLUSIONS

High circulating PAI-1 levels attenuate nutritionally induced obesity. This may be related to modifications in adipose tissue cellularity affecting weight and plasma metabolic parameters.

Stromal cells are the main plasminogen activator inhibitor-1-producing cells in human fat: evidence of differences between visceral and subcutaneous deposits

Elevated plasma plasminogen activator inhibitor (PAI)-1 observed during insulin resistance has been connected with an excessive PAI-1 adipose tissue secretion mainly by visceral fat. Our aim was to compare the localization of PAI-1 in human visceral and subcutaneous fats. PAI-1 secretion was also investigated in vitro during human adipocyte differentiation. PAI-1 antigen and mRNA were localized in the stromal area of the tissue and were also present in a few CD14-positive monocytes, in direct contact with adipocytes. In addition, in subcutaneous tissue, PAI-1 mRNA contents, determined by using real-time polymerase chain reaction, were higher in the stromal fraction than in the adipocyte fraction. PAI-1 mRNA-positive cells were 5-fold more frequent in the visceral area than in the subcutaneous stromal area (P=0.004). Such a difference was also observed for PAI-1 mRNA content between both whole adipose tissues. In contrast to leptin, during adipocyte differentiation, PAI-1 secretion did not follow adipocyte maturation. In situ hybridization in culture did not reveal PAI-1 mRNA in lipid-filled cells. Our results demonstrate that PAI-1 production is mainly due to stromal cells, which were more numerous in the visceral than in the subcutaneous depot. These results could explain the strong relationship observed between circulating PAI-1 levels and the accumulation of visceral fat.

Combined segregation-linkage analysis of plasma thrombin activatable fibrinolysis inhibitor (TAFI) antigen levels with TAFI gene polymorphisms

By decreasing plasminogen binding to fibrin surface, the thrombin activatable fibrinolysis inhibitor (TAFI) has been hypothesized to constitute an early marker for atherothrombotic diseases. Previous studies have shown that plasma TAFI levels exhibit a high interindividual variability that is only poorly explained by lifestyle factors. Several polymorphisms of the TAFI gene have been described, and a combination of a C+1542G substitution in the 3' untranslated region and an Ala147Thr amino acid change has been shown to explain 60% of TAFI variability in a sample of unrelated individuals. A segregation-linkage analysis was performed to determine whether these polymorphisms are directly involved in the genetic regulation of TAFI levels, or whether they are only markers in linkage disequilibrium (LD) with unmeasured TAFI-linked quantitative trait loci (QTLs). The sample consisted of 97 healthy nuclear families from the Stanislas Cohort. The C+1542G and Ala147Thr polymorphisms were in complete negative LD, with minor allele frequencies of 0.27 and 0.28, respectively. Results of the segregation-linkage analysis provided evidence of two TAFI-linked QTLs in LD with the two measured polymorphisms, which would explain 78% of the TAFI variance, as compared with 55% explained by the C+1542G and the Ala147Thr polymorphisms combined. The two putative QTLs would have minor allele frequencies of 0.45 and 0.32, respectively. The hypothesis that one of the measured polymorphisms is one of the QTLs was rejected. The putative QTLs also did not seem compatible with the other TAFI gene polymorphisms that we have previously described. More extensive sequencing of the TAFI gene is necessary to identify the functional variants.

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.

Fat cell function and fibrinolysis

Plasminogen activator inhibitor-1 (PAI-1) is a specific inhibitor of plasminogen activators and may be the principal regulator of plasminogen activation in vivo. PAI-1 levels are elevated in insulin-resistant subjects and are associated with an increased risk of atherothrombosis. After adjustment for metabolic parameters, increased PAI-1 levels were no longer considered as a cardiovascular risk factor. The mechanisms underlying the strong association between PAI-1 levels and the metabolic disturbances found in insulin resistance are still not understood. Several studies have suggested that visceral adipose tissue may be a major source of PAl-1. Accordingly, adipose tissue PAI-1 production particularly that from visceral fat, was found to be elevated in obese human subjects. Within human adipose tissue, stromal cells appear to be the main cells involved in PAI-1 synthesis. This review discusses the potential mechanisms linking adipose tissue to plasma PAI-1 levels such as the intervention of cytokines (TNFalpha and TGFbeta), free fatty acids and hormones (insulin and glucocorticoids). Moreover alteration of adipose tissue cellular composition induced by the modulation of PAI-1 expression opens a novel field of interest.