Phase I trial: the use of autologous cultured adipose-derived stroma/stem cells to treat patients with non-revascularizable critical limb ischemia.

BACKGROUND AIMS: Non-revascularizable critical limb ischemia (CLI) is the most severe stage of peripheral arterial disease, with no therapeutic option. Extensive preclinical studies have demonstrated that adipose-derived stroma cell (ASC) transplantation strongly improves revascularization and tissue perfusion in ischemic limbs. This study, named ACellDREAM, is the first phase I trial to evaluate the feasibility and safety of intramuscular injections of autologous ASC in non-revascularizable CLI patients. METHODS: Seven patients were consecutively enrolled, on the basis of the following criteria: (i) lower-limb rest pain or ulcer; (ii) ankle systolic oxygen pressure <50 or 70 mm Hg for non-diabetic and diabetic patients, respectively, or first-toe systolic oxygen pressure <30 mm Hg or 50 mm Hg for non-diabetic and diabetic patients, respectively; (iii) not suitable for revascularization. ASCs from abdominal fat were grown for 2 weeks and were then characterized. RESULTS: More than 200 million cells were obtained, with almost total homogeneity and no karyotype abnormality. The expressions of stemness markers Oct4 and Nanog were very low, whereas expression of telomerase was undetectable in human ASCs compared with human embryonic stem cells. ASCs (10(8)) were then intramuscularly injected into the ischemic leg of patients, with no complication, as judged by an independent committee. Trans-cutaneous oxygen pressure tended to increase in most patients. Ulcer evolution and wound healing showed improvement. CONCLUSIONS: These data demonstrate the feasibility and safety of autologous ASC transplantation in patients with objectively proven CLI not suitable for revascularization. The improved wound healing also supports a putative functional efficiency.

Effect of clopidogrel on circulating biomarkers of angiogenesis and endothelial activation.

Angiogenic cytokines have been shown to influence vessel injury, and platelets represent a disposable circulating pool of angiogenic molecules. In the present study, objectives were to determine whether clopidogrel could have a potential effect on levels of circulating biomarkers of angiogenesis and endothelial activation. We explored 28 healthy white male volunteers treated for 7 days with clopidogrel 75 mg/day. We quantified angiogenic growth factors that have been shown to be correlated to cardiovascular risk or endothelial progenitor cell mobilization such as vascular endothelial growth factor (VEGF)-A and its soluble receptor forms VEGFR1 and VEGFR2, placenta growth factor, and stromal cell-derived factor-1. We also quantified soluble E-selectin and von Willebrand factor to evaluate endothelial activation. Blood samples were drawn just before the first clopidogrel intake on day 1, and after the last dosing (day 7). As expected, we observed a decrease in platelet reactivity in response to clopidogrel, confirmed by vasodilator-stimulated phosphoprotein phosphorylation assay. However, the 7-day intake of clopidogrel did not significantly modify the levels of the selected angiogenic factors or biomarkers of endothelial activation. These results show that circulating angiogenic factor level in healthy subjects is not driven by P2Y12 platelet receptor-induced activation and clopidogrel does not modify in a significant way the endothelial activation level.

Arterial ultrasound screening as a tool for coronary risk assessment in asymptomatic men and women.

One of the imaging tests most commonly used to assess cardiovascular diseases (CVDs) in daily practice is Doppler ultrasonography of the carotid and femoral arteries. We included 2709 participants with no history or symptoms of CVD; they had a risk factor assessment and a carotid and femoral ultrasonography at baseline. Incident cases of definite coronary events were recorded during a median follow-up of 6 years. Approximately, 63% of the sample presented abnormalities (carotid stenosis >50%, carotid plaque, femoral plaque, increased intima-media thickness [IMT]). A moderately increased IMT (>0.63 mm) or the presence of carotid or femoral artery plaque was related to prognosis. The associations persisted after adjustment for pretest risk, treatment with statins, and other Doppler ultrasonography abnormalities. The hazard ratio increased significantly with the number of abnormalities (varying from 2.35 [1.16-4.74] to 14.83 [6.47-33.9]).

Initial treatment of venous thromboembolism.

Immediate anticoagulant treatment is essential to reduce morbidity and mortality in patients with acute venous thromboembolism (VTE). Currently, rapid anticoagulation can only be achieved with parenteral anticoagulants, such as heparin or low-molecular-weight heparin (LMWH). Weight-adjusted LMWH is the treatment of choice, because it produces predictable anticoagulation and does not require coagulation monitoring. If heparin is used, the activated partial thromboplastin time must be monitored and the heparin dose adjusted to ensure a therapeutic level of anticoagulation. Heparin is recommended for patients with renal impairment and for those at high risk of bleeding. The selective factor Xa inhibitor fondaparinux is a recently introduced alternative to heparin or LMWH for initial VTE treatment. Heparin, LMWH, or fondaparinux should be given for at least five to seven days. Vitamin K antagonists should be initiated on the first day, or as soon as possible, in patients who are candidates for an oral anticoagulant. An oral anticoagulant agent to be used without laboratory monitoring for both acute and long-term treatment of VTE remains an unsolved clinical need in the treatment of VTE.

Cytochrome P450 2C19 loss-of-function polymorphism is a major determinant of clopidogrel responsiveness in healthy subjects.

The capacity of clopidogrel to inhibit ADP-induced platelet aggregation shows wide intersubject variability. To determine whether frequent functional variants of genes coding for candidate cytochrome P450 (CYP) isoenzymes involved in clopidogrel metabolic activation (CYP2C19*2, CYP2B6*5, CYP1A2*1F, and CYP3A5*3 variants) influence the platelet responsiveness to clopidogrel, we conducted a prospective pharmacogenetic study in 28 healthy white male volunteers treated for 7 days with clopidogrel 75 mg/d. We observed that pharmacodynamic response to clopidogrel was significantly associated with the CYP2C19 genotype. Twenty of the subjects were wild-type CYP2C19 (*1/*1) homozygotes, while the other 8 subjects were heterozygous for the loss-of-function polymorphism CYP2C19*2 (*1/*2). Baseline platelet activity was not influenced by the CYP2C19 genotype. In contrast, platelet aggregation in the presence of 10 muM ADP decreased gradually during treatment with clopidogrel 75 mg once daily in *1/*1 subjects, reaching 48.9% +/- 14.9% on day 7 (P < .001 vs baseline), whereas it did not change in *1/*2 subjects (71.8% +/- 14.6% on day 7, P = .22 vs baseline, and P < .003 vs *1/*1 subjects). Similar results were found with VASP phosphorylation. The CYP2C19*2 loss-of-function allele is associated with a marked decrease in platelet responsiveness to clopidogrel in young healthy male volunteers and may therefore be an important genetic contributor to clopidogrel resistance in the clinical setting.

[Thrombophilia and pregnancy: which tests for which patients? The clinician's point of view]. / Thrombophilie et grossesse: quel bilan pour quelles patientes? Le point de vue du clinicien.

Venous thromboembolism is the leading cause of death in the ante-partum and post-partum period. The role of genetic thrombophilia in venous thrombosis has been analyzed in several studies, but the role of genetic thrombophilia in fetal loss, intra-uterine growth restriction and pre-eclampsia is much more controversial. While we can give some recommendations on thromboprophylaxis of venous thromboembolism, data concerning the usefulness of antithrombotic treatment in obstetric complications of genetic thrombophilia are lacking. When a laboratory work-up of thrombophilia is required, all the known causes of thrombophilia must be checked as none of them is specific of a single clinical feature, but also because they can be associated in the same patient.