Meyer Elbaz

Role for Matrix Metalloproteinase-2 in Oxidized Low-Density Lipoprotein-Induced Activation of the Sphingomyelin/Ceramide Pathway and Smooth Muscle Cell Proliferation

Background—Oxidized LDLs (oxLDLs) and matrix metalloproteinases (MMPs) are present in atherosclerotic lesions. OxLDLs activate various signaling pathways potentially involved in atherogenesis. OxLDLs induce smooth muscle cell (SMC) proliferation mediated by the activation of the sphingomyelin/ceramide pathway and tyrosine kinase receptors. MMPs are also able to induce SMC migration and proliferation in addition to extracellular matrix degradation. The present study was designed to investigate whether MMPs play a role in the mitogenic effect of oxLDLs. Methods and Results—OxLDLs induce the release of activated MMP-2 in SMC culture medium. MMP-2 was identified by its 65-kDa gelatinase activity on zymography and by using specific blocking antibodies and MMP-2−/− cells. MMP inhibitors (batimastat and Ro28-2653) and the blocking antibodies anti–MMP-2 and anti–membrane type 1-MMP inhibited the oxLDL-induced sphingomyelin/ceramide pathway activation and subsequent activation of ERK1/2 and DNA synthesis but did not inhibit the oxLDL-induced epidermal growth factor receptor and platelet-derived growth factor receptor activation. Exogenously added activated MMP-2 or membrane type 1-MMP-1 triggered the activation of both sphingomyelin/ceramide and ERK1/2 pathways and DNA synthesis. Conversely, suppression of MMP-2 expression in MMP-2−/− cells or in SMCs treated by small-interference RNA also blocked both sphingomyelin/ceramide signaling and DNA synthesis. Conclusions—Together, these data demonstrate that MMP-2 plays a pivotal role in oxLDL-induced activation of the sphingomyelin/ceramide signaling pathway and subsequent SMC proliferation. These pathways may constitute a potential therapeutic target for modulating the oxLDL-induced proliferation of SMCs in atherosclerosis or restenosis.

Effect of a closure device on complication rates in high‐local‐risk patients: Results of a randomized multicenter trial

Clinical trials have shown that coronary stenting is associated with a high level of complications at the access site. Arterial sealing devices have proven their efficacy in obtaining immediate hemostasis after sheath removal, in allowing early ambulation, and in improving patient comfort. However, there is no report showing a reduction of local complications related to their use. The purpose of this multicenter study was to compare randomly the efficacy of Angio‐Seal versus compression methods of hemostasis in reducing the rate of access site complications after coronary angioplasty in 612 selected patients with higher risk of local events satisfying at least one of the following high‐risk criteria: age > 70, previous puncture at the same site, history of hypertension, treatment with ticlopidine at least 2 days before the procedure, use of abciximab, 8 Fr access, prolonged heparin treatment after the angioplasty, and use of lytics if fibrinogen > 1 g/l. Group A (n = 306) had immediate sheath removal, Angio‐Seal implantation, and cessation of bed rest 4 hr after the intervention. Group B (n = 306) had sheath removal according to local practice and cessation of bed rest 6–18 hr after the hemostasis procedure, also according to local practice. Clinical follow‐up was done at 1 hr, 4 hr, 24 hr, discharge, and 7 days and a systematic color flow duplex sonography was performed to confirm diagnosis of access site complication. In group A, device deployment and immediate hemostasis were obtained in, respectively, 96.8% and 87% of patients. Time to hemostasis was shorter in group A: 5 vs. 52 min (P < 0.001). Cessation of bed rest was dramatically reduced in group A (438 ± 450 min) vs. group B (952 ± 308 min; P < 0.001). The cumulative rate of complications, using a composite primary endpoint, at 7 days was significantly different between the two groups: 5.9% of group A patients and 18% of group B patients (P < 0.001). This difference was mainly due to the dramatic reduction of prolonged bleeding in group A patients. Angio‐Seal device use in high‐local‐risk patients allows immediate sheath removal and hemostasis with a reduction of local event rate despite a higher level of anticoagulation, compared to regular compression techniques, directly related to a dramatic decrease of prolonged bleeding. Cathet Cardiovasc Intervent 2003;58:285–291.

Methylglyoxal induces advanced glycation end product (AGEs) formation and dysfunction of PDGF receptor-β: implications for diabetic atherosclerosis

Purpose: Low molecular weight carbonyl compounds, such as the α‐ketoaldehydes methylglyoxal (MGO) and glyoxal (GO), are formed under hypergly‐cemic conditions and behave as advanced glycation end product (AGE) precursors. They form adducts on proteins, thereby inducing cellular dysfunctions involved in chronic complications of diabetes. Methods and main findings: Nontoxic concentrations of GO or MGO altered the PDGF‐induced PDGFRβ‐phosphorylation, ERKl/2‐activation, and nuclear translocation, and the subsequent proliferation of mesenchymal cells (smooth muscle cells and skin fibroblasts). This resulted mainly from inhibition of the intrinsic tyrosine kinase of PDGFRβ and in part from altered PDGF‐BB binding to PDGFRβ. Concomitantly, the formation of AGE adducts (Nεcarboxyrnethyl‐lysine and Nεcarboxyethyl‐ly‐sine) was observed on immunoprecipitated PDGFRβ. Arginine and aminoguanidine, used as carbonyl scavengers, reversed the inhibitory effect and the formation of AGE adducts on PDGFRβ. AGE‐PDGFRβ adducts were also detected by anti‐AGE antibodies in PDGFRβ immunopurified from aortas of diabetic (streptozoto‐cin‐treated) compared to nondiabetic apolipoprotein E‐null mice. Mass spectrometry analysis of aortas demonstrated increased AGE formation in diabetic specimens. Conclusions: these data indicate that MGO and GO induce desensitization of PDGFRβ that helps to reduce mesenchymal cell proliferation.—Cantero, A.‐V., Portero‐Otín, M., Ayala, V., Auge, N., Sanson, M., Elbaz, M., Thiers, J.‐C., Pamplona, R., Salvayre, R., Negre‐Salvayre, A. Methylglyoxal induces advanced gly‐cation end product (AGEs) formation and dysfunction of PDGF receptor‐β: implications for diabetic atherosclerosis. FASEB J. 21, 3096–3106 (2007)

Two Distinct Calcium-Dependent Mitochondrial Pathways Are Involved in Oxidized LDL-Induced Apoptosis

Objective—Oxidized low-density lipoprotein (oxLDL)–induced apoptosis of vascular endothelial cells may contribute to plaque erosion and rupture. We aimed to clarify the relationship between the oxLDL-induced calcium signal and induction of apoptotic pathways. Methods and Results—Apoptosis was evaluated by biochemical methods, including studies of enzyme activities, protein processing, release of proapoptotic factors, chromatin cleavage, and especially by morphological methods that evaluate apoptosis/necrosis by SYTO-13/propidium iodide fluorescent labeling. The oxLDL-induced sustained calcium rise activated 2 distinct calcium-dependent mitochondrial apoptotic pathways in human microvascular endothelial cells. OxLDLs induced calpain activation and subsequent Bid cleavage and cytochrome C release, which were blocked by calpeptin. Cyclosporin-A inhibited cytochrome C release, possibly by inhibiting the opening of the mitochondrial permeability transition pore (mPTP). Calcineurin, another cyclosporin-sensitive step, was not implicated, because oxLDLs inhibited calcineurin and FK-506 treatment was ineffective. Cytochrome C release in turn induced caspase-3 activation. In addition, oxLDLs triggered release and nuclear translocation of mitochondrial apoptosis-inducing factor through a mechanism dependent on calcium but independent of calpains, mPTP, and caspases. Conclusions—OxLDL-induced apoptosis involves 2 distinct calcium-dependent pathways, the first mediated by calpain/mPTP/cytochrome C/caspase-3 and the second mediated by apoptosis-inducing factor, which is cyclosporin-insensitive and caspase-independent.

Carbonyl scavenger and antiatherogenic effects of hydrazine derivatives.

Reactive carbonyl compounds (RCC) generated by polyunsaturated fatty acid oxidation alter progressively cellular and tissular proteins by forming adducts on free amino groups and thiol residues (carbonyl stress). Carbonyl scavengers may neutralize RCC, but their protective effect in atherosclerosis has not been extensively studied. We report the carbonyl scavenger and antiatherogenic properties of hydrazine derivatives, namely hydralazine, an antihypertensive drug, isoniazid, an antituberculosis agent, and two antidepressants, phenelzine and iproniazid. These drugs were poorly efficient in preventing the oxidation of LDL mediated by smooth muscle cells (SMCs), but inhibited the toxicity of UV-oxidized LDL (oxLDL) and of 4-hydroxynonenal (4-HNE). Hydrazine derivatives prevented the formation of foam cells resulting from LDL oxidation in human macrophagic U937 cells, and blocked the carbonyl stress in SMCs, by inhibiting the decrease in free amino group content, the increase in carbonylated proteins, and the formation of 4-HNE adducts on PDGFR. Experimental studies carried out on apoE-/- mice supplemented with drugs (30 mg/L in drinking water) showed a significant carbonyl stress inhibition correlated with a net reduction of atherosclerotic lesion development. In conclusion, these data indicate that hydrazine derivatives exhibit carbonyl scavenger and antiatherogenic properties, which opens novel therapeutical approaches for atherosclerosis and its cardiovascular complications.

Comparison of direct coronary stenting with and without balloon predilatation in patients with stable angina pectoris

The purpose of this study was to compare the effects of stent placement with and without balloon predilatation on duration of the procedure, reduction of procedure-related costs, and clinical outcomes. Although preliminary trials of direct coronary stenting have demonstrated promising results, the lack of randomized studies with long-term follow-up has limited the critical evaluation of the role of direct stenting in the treatment of obstructive coronary artery disease. Between January and September 1999, 338 patients were randomly assigned to either direct stent implantation (DS+; 173 patients) or standard stent implantation with balloon predilatation (DS-; 165 patients). Baseline clinical and angiographic characteristics were similar in the 2 groups. Procedural success was achieved in 98.3% of patients assigned to DS+ and 97.5% of patients assigned to DS- (p = NS), with a crossover rate of 13.9%. Compared with DS-, DS+ conferred a dramatic reduction in procedure-related cost (

Desensitization of Platelet-Derived Growth Factor Receptor-β by Oxidized Lipids in Vascular Cells and Atherosclerotic Lesions. Prevention by Aldehyde Scavengers

956.4 +/-

No post-conditioning in the human heart with thrombolysis in myocardial infarction flow 2-3 on admission.

352.2 vs

Clinical Assessment of Ischemia-modified Albumin and Heart Fatty Acid–binding Protein in the Early Diagnosis of Non-ST-elevation Acute Coronary Syndrome in the Emergency Department

1,164.6 +/-

Adiponectin and Long-Term Mortality in Coronary Artery Disease Participants and Controls

383.9, p <0.0001) and duration of the procedure (424.2 +/- 412.1 vs 634.5 +/- 390.1 seconds, p < 0.0001). At 6-month follow-up, the incidence of major adverse cardiac events including death, angina pectoris, myocardial infarction, congestive heart failure, repeat angioplasty, or coronary artery bypass graft surgery was 5.3% in DS+ and 11.4% in DS- (p = NS). Multivariate analysis demonstrated that major adverse cardiac events rates were related to stent length of 10 mm (relative risk [RR] 3.25, 95% confidence intervals [CI] 1.36 to 7.78; p = 0.008), stent diameter of 3 mm (RR 2.69, 95% CI 1.03 to 7.06; p = 0.043), and complex lesion type C (RR 2.83, 95% CI 1.02 to 7.85; p = 0.045). Thus, in selected patients, this prospective randomized study shows the feasibility of DS+ with reduction in procedural cost and length, and without an increase in in-hospital clinical events and major adverse cardiac events at 6-month follow-up.