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Objective Neutrophil gelatinase-associated lipocalin (NGAL), a protein found in activated neutrophils, is expressed in kidney tubule cells in response to noxious stimuli, and is thus recognized as a marker of acute kidney injury. Recent studies have suggested that NGAL could also have pathophysiological importance in cardiovascular diseases. The aim of the present study was to examine NGAL expression in human carotid endarterectomy tissues ex vivo as well as the effects of NGAL in the main cell types involved in atherogenesis, namely in human macrophages, endothelial cells, and smooth muscle cells in vitro. Methods NGAL protein was analyzed in human endarterectomy samples from patients with asymptomatic and symptomatic carotid stenosis by immunofluorescence, and NGAL mRNA expression was detected using RealTime-PCR. Human monocyte derived macrophages (MDM), human coronary artery smooth muscle cells (HCASMC), and human umbilical vein endothelial cells (HUVEC) were treated with recombinant human (rh) NGAL at different concentrations. Interleukin (IL)-6, IL-8, and monocyte chemo-attractant protein-1 (MCP-1) were determined by specific enzyme linked immunosorbent assays (ELISAs) in culture supernatants of such treated cells. Results Expression of NGAL protein was demonstrated by macrophages, smooth muscle cells, and endothelial cells in human carotid atherosclerotic tissue. NGAL mRNA expression was detected at a higher rate in atherosclerotic tissue of patients with symptomatic carotid stenosis (in 70%; n = 19) compared with asymptomatic patients (in 37%; n = 20, p < .001). Treatment of MDM, HCASMC, and HUVEC with rhNGAL led to a significant ( p < 0.05) and concentration dependent increase of pro-inflammatory cytokines IL-6, IL-8, and MCP-1 in all cell types analyzed. Conclusion By induction of pro-inflammatory mediators in human macrophages, smooth muscle cells and endothelial cells, NGAL, which is predominantly expressed in atherosclerotic plaques of symptomatic patients, could be involved in creating the local and systemic pro-inflammatory environment characteristic for atherosclerosis. [ABSTRACT FROM AUTHOR]

Aging is a major factor predisposing for multiple diseases. Telomeres at the ends of chromosomes protect the integrity of chromosomal DNA. A specialized six-protein complex termed shelterin protects the telomere from unwanted interaction with DNA damage pathways. The aim of our study was to evaluate the integrity of telomeres and the stability of telomere protection during aging in endothelial cells (EC). We describe that aging EC can be characterized by an increased cell size (40%, p = 0.02) and increased expression of PAI 1 (4 fold, p = 0.02), MCP1 (10 fold, p = 0.001) and GMCSF (15 fold, p = 0.004). Telomeric state in aging cells is defined by an increased telomere oxidation (27%, p = 0.01), reduced telomere length (62%, p = 0.02), and increased DNA damage foci formation (5% in young EC versus 16% in aged EC, p = 0.003). This telomeric dysfunction is accompanied by a reduction in the shelterin component TRF1 (33% mRNA, p = 0.001; 24% protein, p = 0.007). Overexpression of TRF1 in aging EC reduced telomere-associated DNA damage foci to 5% (p = 0.02) and reduced expression levels of MCP1 (18% reduction, p = 0.008). Aged EC have increased telomere damage and an intrinsic loss of telomere protection. Reestablishing telomere integrity could therefore be a target for rejuvenating endothelial cell function. [ABSTRACT FROM AUTHOR]

Abstract: Recent reports have implicated osteoprotegerin (OPG) in cardiovascular disease processes. Endothelial and smooth muscle cells produce OPG and its expression in these cells is upregulated by inflammatory mediators. Statins, which besides their lipid lowering properties have various vasculoprotective effects, have been shown to regulate OPG expression in osteoblasts. We investigated whether statins affect the expression of OPG in human endothelial and smooth muscle cells. Using an ELISA we could demonstrate that statins reduce tumor necrosis factor-α (TNF-α)-induced OPG production in cultured human endothelial cells and smooth muscle cells. Atorvastatin also downregulated interleukin-1α (IL-1α)-induced OPG production in endothelial cells. A significant reduction of TNF-α-induced OPG was seen when statins were used in the nanomolar range. These results were confirmed at the level of specific mRNA expression by real-time-PCR. Using LDH leakage as a marker of cell damage we show that cell viability was not affected by statins at concentrations used in our study. The effect of statins on TNF-α-induced OPG production was reversed by mevalonate and geranyl–geranyl pyrophosphate at the level of protein production and at the level of mRNA expression, suggesting that it was brought about by inhibition of the mevalonic acid pathway and protein prenylation. Through our results we have added OPG to the list of molecules whose TNF-α-induced upregulation is counteracted by statins. If such an effect is also operative in the in vivo setting, one could postulate a role for statins in the modulation of cardiovascular disease processes possibly regulated by OPG. [Copyright &y& Elsevier]