Presence of a mobilizable intracellular pool of hepatocyte growth factor in human polymorphonuclear neutrophils

Hepatocyte growth factor (HGF), a heparin-binding factor, is synthesized as a single-chain inactive precursor (pro-HGF), which is converted by proteolysis to an active heterodimer (mature HGF). HGF has pleiotropic activities and has been implicated in the regulation of mitogenesis, motogenesis, and morphogenesis of epithelial and endothelial cells. As polymorphonuclear neutrophils (PMNs) secrete numerous cytokines involved in the modulation of local inflammation, we investigated their ability to produce HGF. We found that HGF was stored in secretory vesicles and in gelatinase/specific granules. This intracellular stock was rapidly mobilized by degranulation when neutrophils were stimulated with phorbol myristate acetate or N-formylmethionyl-leucyl-phenylalanine. Cycloheximide did not affect the release of HGF. Moreover, HGF messenger RNA and protein expression was found in bone marrow myeloid cells, suggesting that HGF synthesis likely occurs during PMN maturation. In mature circulating PMNs, intracellular HGF was in the pro-HGF form, whereas the HGF secreted by degranulation was the mature form. Furthermore, PMNs pretreated with diisopropyl fluorophosphate only released the pro-HGF form, suggesting that PMN-derived serine protease(s) are involved in the proteolytic process. We also obtained evidence that secreted mature HGF binds PMN-derived glycosaminoglycans (probably heparan sulfate). These findings suggest that PMNs infiltrating damaged tissues may modulate local wound healing and repair through the production of HGF, a major mediator of tissue regeneration.     

Signaling through ZAP-70 is required for CXCL12-mediated T-cell transendothelial migration

Transendothelial migration of activated lymphocytes from the blood into the tissues is an essential step for immune functions. The housekeeping chemokine CXCL12 (or stroma cell-derived factor-1alpha), a highly efficient chemoattractant for T lymphocytes, drives lymphocytes to sites where they are highly likely to encounter antigens. This suggests that cross-talk between the T-cell receptor (TCR) and CXCR4 (the CXCL12 receptor) might occur within these sites. Here we show that the zeta-associated protein 70 (ZAP-70), a key element in TCR signaling, is required for CXCR4 signal transduction. The pharmacologic inhibition of ZAP-70, or the absence of ZAP-70 in Jurkat T cells and in primary CD4(+) T cells obtained from a patient with ZAP deficiency, resulted in an impairment of transendothelial migration that was rescued by the transfection of ZAP-70. Moreover, the overexpression of mutated forms of ZAP-70, whose kinase domain was inactivated, also abrogated the migratory response of Jurkat T cells to CXCL12. In contrast, no involvement of ZAP-70 in T-cell arrest on inflammatory endothelium under flow conditions or in CXCL12-induced actin polymerization was observed. Furthermore, CXCL12 induced time-dependent phosphorylation of ZAP-70, Vav1, and extracellular signal-regulated kinases (ERKs); the latter were reduced in the absence of functional ZAP-70. However, though a dominant-negative Vav1 mutant (Vav1 L213A) blocked CXCL12-induced T-cell migration, pharmacologic inhibition of the ERK pathway did not affect migration, suggesting that ERK activation is dispensable for T-cell chemotaxis. We conclude that cross-talk between the ZAP-70 signaling pathway and the chemokine receptor CXCR4 is required for T-cell migration.     

Skeletal myoblast transplantation through a catheter-based coronary sinus approach: an effective means of improving function of infarcted myocardium.

AIMS: This study was designed to assess the functional effects of a transvenous coronary sinus technique of skeletal myoblast delivery in infarcted myocardium. METHODS AND RESULTS: An anterior myocardial infarction was created percutaneously in 14 sheep. Simultaneously, a muscle biopsy was harvested and expanded. Two weeks later, sheep were instrumented percutaneously with a dedicated catheter incorporating an extendable needle for puncture of the venous wall and, under endovascular ultrasound guidance, a microcatheter was advanced through the needle into the target scar for cell delivery. Following the baseline echocardiographic assessment of left ventricular (LV) function, sheep were randomly allocated to receive four-staged in-scar injections of either autologous cells (n=7) or culture medium (n=7). Two months later, LV function was reassessed blindly and hearts were explanted for subsequent histological and immunohistochemical analysis. There were no acute procedural complications. Baseline LV ejection fraction (EF) was significantly lower in transplanted sheep than in controls [38% (35-48) vs. 51% (38-55), respectively, P=0.03; median (range)]. Two months later, LVEF was significantly higher in the transplanted group than in controls [50% (47-56) vs. 39% (36-47), respectively, P=0.002]. Clusters of myoblasts were identified by histology and immunohistochemistry in three of the seven transplanted sheep. CONCLUSION: These data suggest the functional efficacy of the transvenous coronary sinus technique as a less invasive means of cell delivery to infarcted myocardium.     

Sustained elevation of extracellular dopamine causes motor dysfunction and selective degeneration of striatal GABAergic neurons

Dopamine is believed to contribute to the degeneration of dopamine-containing neurons in the brain. However, whether dopamine affects the survival of other neuronal populations has remained unclear. Here we document that mice with persistently elevated extracellular dopamine, resulting from inactivation of the dopamine transporter gene, sporadically develop severe symptoms of dyskinesia concomitant with apoptotic death of striatal dopamine-responsive gamma-aminobutyric acidergic neurons. Chronic inhibition of dopamine synthesis prevents the appearance of motor dysfunction. The neuronal death is associated with overactivation of dopaminergic signaling as evidenced by the robust up-regulation of striatal DeltaFosB, cyclin-dependent kinase 5, and p35. Moreover, hyperphosphorylation of the tau protein, a phenomenon associated with the activation of cyclin-dependent kinase 5 in several neurodegenerative disorders, is observed in symptomatic mice. These findings provide in vivo evidence that, in addition to its proposed role in the degeneration of dopamine neurons, dopamine can also contribute to the selective death of its target neurons via a previously unappreciated mechanism.     

A prospective study on the evolution of the T-cell repertoire in patients with Sézary syndrome treated by extracorporeal photopheresis

Sézary syndrome is a leukemic form of epidermotropic cutaneous T-cell lymphoma related to the malignant proliferation of clonal CD4(+) T cells. Extracorporeal photochemotherapy may induce a transient improvement of the clinical signs, but its efficiency is discussed. To investigate the frequency of the T-cell clone in the peripheral blood of patients with Sézary syndrome and to monitor its evolution in patients treated using extracorporeal photopheresis or chemotherapy, we used the immunoscope technique. In one patient, we observed a decrease of the relative frequency of the clone from 15.6% to 0%, paralleling a complete remission of the clinical disease and a disappearance of the circulating Sézary cells. In the other cases, the evolution of the relative frequency paralleled the initial improvement of the clinical status and the absence of long-term efficiency in patients treated with extracorporeal photopheresis or chemotherapy. We observed a quick-acting direct cytotoxicity of the association 8MOP + UVA on the T-cell clone. The immunoscope technique appears to be an efficient tool to appreciate the amount of tumoral cells and to monitor the evolution of the clonal component in the Sézary syndrome.     

Homocysteine is the only plasma thiol associated with carotid artery remodeling

Several authors have reported that moderate hyperhomocysteinemia is related to asymptomatic carotid arterial wall remodeling, but few data are available on other thiol compounds with potential vascular toxicity. We, therefore, investigated the relationships between major plasma thiol compounds (homocysteine, cysteine and glutathione) and the structural phenotype of the common carotid artery in a cohort of 123 subjects with no evidence of cardiovascular disease. Fasting levels of thiol compounds were measured by high-performance liquid chromatography, and arterial geometry was evaluated using high-resolution echotracking devices. In univariate regression analysis, plasma homocysteine and plasma cysteine concentrations were positively associated with carotid artery internal diameter (P=0.0001 and 0.002, respectively) and intima media thickness (P=0.003 and 0.004), but the plasma glutathione concentration was not. In multivariate analysis, plasma homocysteine was independently and positively associated with carotid artery internal diameter (P<0.005) and intima media thickness (P<0.05), but plasma cysteine was not. These data suggest that homocysteine is the only plasma thiol compound that may be considered as a risk factor for preclinical cardiovascular disease.     

Echocardiography remains the standard for the diagnostic evaluation of left ventricular tumors: a case report with anatomical correlation.

Primary cardiac tumors are rare. Although the majority are benign, they may cause significant morbidity and mortality. Two-dimensional transthoracic echocardiography (2D-TTE) is the primary imaging modality for the diagnosis of cardiac tumors. New and more complex non-invasive imaging modalities, such as cardiac magnetic resonance (CMR), do not always provide an added value. This is illustrated in the presented case report of a papillary fibroelastoma (PFE).     

Myeloma in patients younger than age 50 years presents with more favorable features and shows better survival: an analysis of 10 549 patients from the International Myeloma Working Group

We analyzed the presenting features and survival in 1689 patients with multiple myeloma aged younger than 50 years compared with 8860 patients 50 years of age and older. Of the total 10 549 patients, 7765 received conventional therapy and 2784 received high-dose therapy. Young patients were more frequently male, had more favorable features such as low International Staging System (ISS) and Durie-Salmon stage as well as less frequently adverse prognostic factors including high C-reactive protein (CRP), low hemoglobin, increased serum creatinine, and poor performance status. Survival was significantly longer in young patients (median, 5.2 years vs 3.7 years; P < .001) both after conventional (median, 4.5 years vs 3.3 years; P < .001) or high-dose therapy (median, 7.5 years vs 5.7 years; P = .04). The 10-year survival rate was 19% after conventional therapy and 43% after high-dose therapy in young patients, and 8% and 29%, respectively, in older patients. Multivariate analysis revealed age as an independent risk factor during conventional therapy, but not after autologous transplantation. A total of 5 of the 10 independent risk factors identified for conventional therapy were also relevant for autologous transplantation. After adjusting for normal mortality, lower ISS stage and other favorable prognostic features seem to account for the significantly longer survival of young patients with multiple myeloma with age remaining a risk factor during conventional therapy.