Effects of Preinjury Administration of Corticosteroids on Pseudointimal Hyperplasia and Cytokine Response in a Rat Model of Balloon Aortic Injury

Effects of glucocorticoid agonist and antagonist on the pathogenesis of L-arginine-induced acute pancreatitis in rat

OBJECTIVES

To investigate the consequences of treatment with an exogenous glucocorticoid agonist (methylprednisolone) and antagonist (RU-38486) on the local and systemic responses in L-arginine-induced acute pancreatitis in rats.

METHODS

The methylprednisolone and RU-38486 were administered just before pancreatitis induction. Plasma amylase activity, interleukin 6 activity, pancreatic weight/body weight ratio, plasma macrophage migration inhibitory factor (MIF) concentration, and pancreatic nuclear transcription factor (NF) kappaB activity were determined. The extents of pancreas, liver, and lung injuries were assessed by histology.

RESULTS

Acute pancreatitis resulted in NF-kappaB activation and proinflammatory cytokine release in rats. In the glucocorticoid agonist group, plasma amylase and interleukin 6 levels were significantly decreased as compared with those of RU-38486 and nontreated groups. Antagonist treatment led to significantly higher MIF production at 8 and 12 hours after L-arginine injection as compared with the agonist-treated and nontreated groups. Glucocorticoid agonist treatment significantly decreased the level of NF-kappaB 24 hours after pancreatitis induction. Histological investigations showed protective effect of agonist treatment on acute pancreatitis-induced tissue damage in the pancreas and lung.

CONCLUSIONS

These results corroborated the importance of MIF in acute pancreatitis. The glucocorticoid-dependent mechanisms seem to play a crucial role in the control of the inflammatory response and tissue damage in L-arginine-induced experimental acute pancreatitis.

Novel blocker of NFAT activation inhibits IL-6 production in human myometrial arteries and reduces vascular smooth muscle cell proliferation

The calcineurin/nuclear factor of activated T cells (NFAT) signaling pathway has been found to play a role in regulating growth and differentiation in several cell types. However, the functional significance of NFAT in the vasculature is largely unclear. Here we show that NFATc1, NFATc3, and NFATc4 are expressed in human myometrial arteries. Confocal immunofluorescence and Western blot analysis revealed that endothelin-1 efficiently increases NFATc3 nuclear accumulation in native arteries. Endothelin-1 also stimulates NFAT-dependent transcriptional activity, as shown by a luciferase reporter assay. Both the agonist-induced NFAT nuclear accumulation and transcriptional activity were prevented by the calcineurin inhibitor CsA and by the novel NFAT blocker A-285222. Chronic inhibition of NFAT significantly reduced IL-6 production in intact myometrial arteries and inhibited cell proliferation in vascular smooth muscle cells cultured from explants from the same arteries. Furthermore, by using small interfering RNA-mediated reduction of NFATc3, we show that this isoform is involved in the regulation of cell proliferation. Protein synthesis in intact arteries was investigated using autoradiography of [(35)S]methionine incorporation in serum-free culture. Inhibition of NFAT signaling did not affect overall protein synthesis or specifically the synthesis rates of major proteins associated with the contractile/cytoskeletal system. An intact contractile phenotype under these conditions was also shown by unchanged force response to depolarization or agonist stimulation. Our results demonstrate NFAT expression and activation in native human vessels and point out A-285222 as a powerful pharmacological blocker of NFAT signaling in the vasculature.

EFFECTS OF DEXAMETHASONE ON MACROPHAGE MIGRATION INHIBITORY FACTOR PRODUCTION IN SEPSIS

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that plays a major role in the pathogenesis of sepsis. Some studies have indicated that glucocorticoids increase MIF production in physiological conditions. The goal of this study was to determine whether glucocorticoid treatment also upregulates MIF production in sepsis. Male NMRI mice (6-10 weeks old) underwent laparotomy, proximal ligation of the cecum, and double perforation with a 19-gauge needle (cecal ligation and puncture). Mice were randomly treated with saline (control) or dexamethasone at doses of 0.1, 1, or 10 mg/kg ip. At 6 or 18 h postoperatively, 10 mice per group were euthanized; and blood, peritoneal fluid, liver, lung, kidney, and heart tissue samples were retrieved. MIF, IL-6, TNF-alpha, and IL-10 were measured by enzyme-linked immunosorbent assay. Sepsis induced by cecal ligation and puncture produced a marked increase in MIF and cytokine levels in plasma and peritoneal fluid. Treatment with dexamethasone 10 mg/kg decreased MIF levels in plasma after 18 h, but there was no effect of dexamethasone on MIF production locally in the peritoneal cavity or in the liver, lungs, heart, or kidneys. We conclude that glucocorticoid treatment does not upregulate MIF production in sepsis.

Early elevation of interleukin-1beta and interleukin-6 levels after bare or drug-eluting stent implantation in patients with stable angina

INTRODUCTION

Drug-eluting stent (DES) implantation represents an important innovation in the treatment of coronary artery disease. However, inflammatory-related complications, including subacute thrombosis and in-stent restenosis, are still important limitations to percutaneous coronary intervention (PCI). The aim of this study was to compare early local release of interleukin 1beta (IL-1beta) and IL-6 proinflammatory cytokines after elective placement of either bare metal stents or DES.

MATERIALS AND METHODS

IL-1beta and IL-6 levels were assayed in plasma obtained from the coronary sinus both before and 20 min after stent implantation in 59 patients with stable angina, who were randomly assigned to receive bare, paclitaxel-, or sirolimus-eluting stents during elective PCI.

RESULTS

We found that IL-1beta and IL-6 levels were significantly increased in the coronary sinus of patients receiving either bare, paclitaxel- or sirolimus-eluting stents 20 min after stent implantation as compared with basal concentrations. The variation in the level of both cytokines was comparable among the three study groups.

CONCLUSIONS

A local release of proinflammatory cytokines occurs shortly after coronary stent placement, including DES, which is possibly related to plaque rupture and/or endothelium traumatism following the stenting procedure. This suggests that precocious anti-inflammatory treatment could be of benefit to further improve the PCI clinical outcome.