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Thrombin is a multifunctional serine protease generated at the site of vascular injury that transforms fibrinogen into fibrin, activates blood platelets and elicits multiple effects on a variety of cell types including endothelial cells, vascular smooth muscle cells (VSMC), monocytes, T lymphocytes and fibroblasts. Cellular effects of thrombin are mediated by protease-activated receptors (PARs), members of the G protein-coupled receptors that carry their own ligand which remains cryptic until unmasked by proteolytic cleavage. Thrombin signalling in platelets contributes to haemostasis and thrombosis. In normal arteries PARs are mainly expressed in endothelial cells, while their expression in VSMC is limited. Endothelial PARs participate in the regulation of vascular tone, vascular permeability and endothelial secretory activity while in VSMC they mediate contraction, migration, proliferation, hypertrophy and production of extracellular matrix. PARs contribute to the pro-inflammatory phenotype observed in endothelial dysfunction and their up-regulation in VSMC seems to be a key element in the pathogenesis of atherosclerosis and restenosis. In the last years a myriad of studies have emphasized the critical role of PAR signalling in thrombin mediated effects in haemostasis, inflammation, cancer and embryonic development. Lately, PARs have become a therapeutic target to inhibit platelet aggregation and thrombosis. Early data from a clinical trial (TRA-PCI) to evaluate safety and efficacy of a potent new oral thrombin receptor antagonist (TRA) have promisingly indicated that overall TRA treatment reduces adverse event rates without an increase in bleeding risk. In this paper we review cellular responses triggered by thrombin and their implication in vascular pathophysiology.

Lysyl oxidase (LOX) plays a crucial role in the maintenance of extracellular matrix stability and could participate in vascular remodelling associated with cardiovascular diseases. Evidence from in vitro and in vivo studies shows that LOX downregulation is associated with the endothelial dysfunction characteristic of earlier stages of the atherosclerotic process. Conversely, upregulation of this enzyme in vascular cells could induce neointimal thickening in atherosclerosis and restenosis. In fact, LOX is chemotactic for vascular smooth muscle cells and monocytes, is modulated by proliferative stimulus in these cells, and could control other cellular processes such as gene expression and cell transformation. Furthermore, it is conceivable that LOX downregulation could underlie plaque instability and contribute to the destructive remodelling that takes place during aneurysm development. Overall, LOX could play a key role in vascular homeostasis and, hence, it emerges as a new player in cardiovascular diseases. This review addresses the experimental evidence related to the role of LOX in vascular disorders and the potential benefits of controlling its expression and function.

Background-Low-density lipoprotein (LDL) receptor-related protein (LRP) is highly expressed in vascular smooth muscle cells (VSMCs) of both normal and atherosclerotic lesions. However, little is known about LRP regulation in the vascular wall. Methods and Results-We analyzed the regulation of LRP expression in vitro in human VSMCs cultured with native LDL (nLDL) or aggregated LDL (agLDL) by semiquantitative reverse transcriptase-polymerase chain reaction, real-time polymerase chain reaction, and Western blot and in vivo during diet-induced hypercholesterolemia by in situ hybridization. LRP expression in human VSMCs is increased by nLDL and agLDL in a time-and dose-dependent manner. Maximal induction of LRP mRNA expression was observed after 24 hours of exposure to LDL. However, agLDL induced higher LRP mRNA expression (3.0-fold) than nLDL (1.76-fold). LRP mRNA upregulation was associated with an increase on LRP protein expression with the greatest induction by agLDL. VSMC-LRP upregulation induced by nLDL or agLDL was reduced by an inhibitor of sterol regulatory element binding protein (SREBP) catabolism (N-acetyl-leucyl-leucyl-norleucinal). In situ hybridization analysis indicates that there is a higher VSMC-LRP expression in hypercholesterolemic than in normocholesterolemic pig aortas. Conclusions-These results indicate that LRP expression in VSMCs is upregulated by intravascular and systemic LDL.

Abstract. In marine ecosystems climatic fluctuation and other physical variables greatly influence population dynamics, but differential effects of physical variables on the demographic parameters of the two sexes and different age classes are largely unexplored. We analyzed the effects of climate on the survival and recruitment of both sexes and several age classes of a long-lived tropical seabird, the Blue-footed Booby (Sula nebouxii ), using longterm observations on marked individuals. Results demonstrated a complex interaction between yearly fluctuations in climate (both local and global indexes, during both winter and breeding season) and the sex and age of individuals. Youngest birds' survival and recruitment were commonly affected by local climate, whereas oldest birds' parameters tended to be constant and less influenced by environmental variables. These results confirm the theoretical prediction that sex-and age-related variation in life-history demographic traits is greater under poor environmental conditions, and they highlight the importance of including variability in fitness components in demographic and evolutionary models. Males and females showed similar variation in survival but different recruitment patterns, in relation to both age and the spatial scale of climatic influence (local or global). Results indicate different lifehistory tactics for each sex and different ages, with birds likely trying to maximize their fitness by responding to the environmental contingencies of each year.

In utero exposure to anti-TNFα drugs does not seem to be associated with increased short-term or long-term risk of severe infections in children.

The incidence rate of inflammatory bowel disease relapse after anti-TNF discontinuation is relevant. Some predictive factors of relapse after anti-TNF withdrawal have been identified. Retreatment with the same anti-TNF drug was effective and safe.