Postprandial serum induces apoptosis in endothelial cells: role of plymorphonuclear-derived myeloperoxidase and metalloproteinase-9 activity

Postprandial state is a pro-inflammatory condition associated with a transient impairment of endothelial function. Recent evidence suggests that myeloperoxidase (MPO) and matrix metalloproteinase-9 (MMP-9) are involved in the pathogenesis of inflammatory vascular diseases such as atherosclerosis. The present study was carried out to investigate whether a fat meal induces polymorphonuclear (PMN) activation and increases the plasma activity of MPO and MMP-9 and whether postprandial serum exerts pro-apoptotic effects on endothelial cells. Fifteen healthy young men underwent a high-fat challenge containing 60 g butter. Blood samples were drawn before, and 1, 2, and 4 h after the meal. Leukocyte reactive oxygen species (ROS) production, plasma MPO and MMP-9 activity, endothelial-derived soluble CD 146 levels, and advanced oxidation protein product (AOPP) levels were determined. Human umbilical vein endothelial cells (HUVECs) were treated with human sera to evaluate mitochondrial membrane potential, ROS production, annexin PI staining, and caspase-3 activity. Triglycerides, ROS production, MPO activity, AOPP levels, pro-MMP-9 zymographic activity, and soluble CD146 levels significantly increased during the 4 h after the test meal. Postprandial serum significantly decreased the mitochondrial membrane potential, and increased the rate of ROS production, the percentage of annexin-positive HUVECs, and caspase-3 activity. A strong relationship was observed between postprandial increase in PMN-derived MPO and pro-MMP-9 activity, and the increased rate of apoptosis of endothelial cells exposed to postprandial serum. Data show that postprandial serum exerts pro-apoptotic effects on endothelial cells. The close relationships between markers of endothelial cell apoptosis and MPO and pro-MMP-9 activity suggest that the latter may contribute to the development of fat meal induced endothelial damage. (C) 2007 Elsevier Ireland Ltd. All rights reserved

Increased neutrophil lifespan in patients with congestive heart failure.

AIMS: Congestive heart failure (CHF) can be thought of as a state of chronic immune activation. Polymorphonuclear neutrophil (PMN) apoptosis is one of the mechanisms responsible for the resolution of inflammation. A reduced PMN apoptotic rate in CHF patients may generate a persistent inflammatory response and hence mediate tissue damage in this group of patients. We aimed to measure levels of spontaneous apoptosis of circulating PMNs in CHF patients and in controls, and to examine whether NYHA class, left ventricular ejection fraction (LV-EF), and laboratory parameters of inflammation, endothelial damage, and of liver and renal function, could predict the rate of PMN apoptosis in CHF patients. METHODS AND RESULTS: A total of 29 CHF patients and 26 controls were studied. Propidium iodide and flow cytometry were used to assess PMN apoptosis. Delay in PMN apoptosis was expressed as percentage (expressed as median, first and third quartiles) of surviving PMNs in the study subjects. We found an increased percentage of surviving PMNs [38(27.1-47.1)] in CHF patients compared with controls [19.4 (15.8-25.2)] (P < 0.05). The PMN survival rate in the CHF group was correlated to NYHA class, and plasma levels of C-reactive protein and alkaline phosphatase, while it was inversely correlated to LV-EF and protein levels. A positive relationship between PMN survival and increased ex vivo endothelial apoptosis was found.CONCLUSION: Increased PMN lifespan in patients with worsening CHF could be used as a novel measurement of tissue and endothelial damage in this group of patients

Role of Cell-Cell bond for the viability and the function of vascular smooth muscle cells

Vascular smooth muscle cell (VSMC) viability and homeostasis is regulated by cell-matrix and cell-cell contact: disruption of these interactions are responsible of a switch from a mature to a high proliferative phenotype. VSMCs migration, rate of growth and apoptosis, and the extent of their extracellular matrix (ECM) deposition can be also modulated by proatherogenic peptides. Among them, ATII induces the transactivation of IGF I R, which, together with the binding protein IGFBP3, represents a determinant of cell survival, growth and proliferation. Aim of our in vitro study was to verify the role of elective cell-cell bond in moulating the response to ATII. Thus, we evaluated viability, proliferation, IGFIR, IGFBP3 expression and the long term survival and production of ECM in a provisional tissue. A7r5 cell-line was used in adherent cultures or incubated in agarose-coated culture plates to inhibit cell-matrix interactions. Cells, treated or not with ATII 100 nM, were evaluated for apoptosis rate, cell cycle, IGFIR and IGFBP3 protei expression. Fibrin provisional tissue was developed polymerizing a fibrin solution. cantaining A7r5 cells with thrombin. Histological stainings for ECM components were performed on sections of prvisional tissue. An exclusive cell-cell contact resulted to monolayer cell cultures. ATII did not affect the cell survival in both culture conditions, but promoted a 10% decrease in "S" phase and an increases IGFIR expression only in adherent cells. while suspended cell aggregates were resistant to ATII administration; IGFBP3 was reduced both in ATII treated adherent cells and in floating clustered cells, irrespective of the treatmentn. VSMC conditioning in agarose-coated plates before seeding in fibrin provisional matrix reduced, but not abolished, the cell ability to colonize the clot and to produce ECM. This study demonstrates that the elective cell-cell contact induces a quiescent status in cells lacking of cell-matrix interactions and reduces the responsiveness to ATII. Therefore, preserved cell-cell contac may couteract vascular remodeling induced by proatherogenic stimuli