55 research outputs found
”Fluvastatin treatment inhibits leucocyte adhesion and extravasation in models of complement-mediated acute inflamation”F.Fischetti, R. Carretta, G. Borotto, P. Durigutto, R. Bulla, P.L. Meroni, F. Tedesco.
No full textAbstract
Complement activation plays a relevant role in the development of tissue damage under inflammatory conditions, and clinical and experimental observations emphasize its contribution to inflammatory vasculitides. Statins have recently been shown to reduce cardiovascular morbidity independently of plasma cholesterol lowering and in vitro studies support a direct anti-inflammatory action of these drugs. The aim of this study was to verify the in vivo effect of fluvastatin on complement-mediated acute peritoneal inflammation. The effect of oral treatment with fluvastatin was investigated in normo-cholesterolaemic rats that received intraperitoneal injection of either yeast-activated rat serum (Y-act RS) or lipopolysaccharide to induce peritoneal inflammation monitored by the number of PMN recruited in peritoneal fluid washes. In addition, vascular adherence and extravasation of leucocytes were evaluated by direct videomicroscopy examination on mesentery postcapillary venules topically exposed to Y-act RS. The number of PMN in the peritoneal washes of rats treated with fluvastatin was 38% lower than that of untreated animals (P < 0.05) 12 h after LPS injection, and was even lower (56%) in rats treated with Y-act RS already 8 h after injection (P < 0.02). Firm adhesion to endothelium and extravasation of leucocytes evaluated under direct videomicroscopy observation were significantly inhibited in fluvastatin treated rats (77% and 72%, respectively; P < 0.01), 120 min after treatment with Y-act RS. Our results demonstrate that fluvastatin inhibits in vivo complement-dependent acute peritoneal inflammation and suggest a role for statins in preventing the inflammatory flares usually associated with complement activation in chronic diseases, such as SLE or rheumatoid arthritis
Control of apoptosis-induced ischemia/reperfusion injury by a neutralizing scFv anti-C5 antibody in heterotopic rat heart transplantation
No full textFluvastatin treatment inhibits leucocyte adhesion and extravasation in models of complement-mediated acute inflammation.
No full textComplement activation plays a relevant role in the development of tissue damage under inflammatory conditions, and clinical and experimental observations emphasize its contribution to inflammatory vasculitides. Statins have recently been shown to reduce cardiovascular morbidity independently of plasma cholesterol lowering and in vitro studies support a direct anti-inflammatory action of these drugs. The aim of this study was to verify the in vivo effect of fluvastatin on complement-mediated acute peritoneal inflammation. The effect of oral treatment with fluvastatin was investigated in normo-cholesterolaemic rats that received intraperitoneal injection of either yeast-activated rat serum (Y-act RS) or lipopolysaccharide to induce peritoneal inflammation monitored by the number of PMN recruited in peritoneal fluid washes. In addition, vascular adherence and extravasation of leucocytes were evaluated by direct videomicroscopy examination on mesentery postcapillary venules topically exposed to Y-act RS. The number of PMN in the peritoneal washes of rats treated with fluvastatin was 38% lower than that of untreated animals (P < 0.05) 12 h after LPS injection, and was even lower (56%) in rats treated with Y-act RS already 8 h after injection (P < 0.02). Firm adhesion to endothelium and extravasation of leucocytes evaluated under direct videomicroscopy observation were significantly inhibited in fluvastatin treated rats (77% and 72%, respectively; P < 0.01), 120 min after treatment with Y-act RS. Our results demonstrate that fluvastatin inhibits in vivo complement-dependent acute peritoneal inflammation and suggest a role for statins in preventing the inflammatory flares usually associated with complement activation in chronic diseases, such as SLE or rheumatoid arthritis
Thrombus formation induced by antibodies to beta2-glycoprotein I is complement dependent and requires a priming factor.
No full textAbstract
We monitored the number of intravascular platelet-leukocyte aggregates (PLAs) and thrombotic occlusions (TOs) by intravascular microscopy in the mesentery of rats receiving antiphospholipid (aPL) immunoglobulin G (IgG) purified from the sera of patients with antiphospholipid syndrome. aPL IgG had no procoagulant effect, but it caused rapid endothelial deposition of fibrinogen, followed by PLA and TO in rats receiving an intraperitoneal injection of bacterial lipopolysaccharide 3 hours before IgG infusion. Anti-beta2-glycoprotein I-depleted aPL IgG failed to induce PLAs and TOs. C3 and C9 colocalized with aPL IgG on the mesenteric vessels. The number of PLAs and TOs was markedly reduced in C6-deficient rats and in animals treated with anti-C5 miniantibody, suggesting the contribution of the terminal complement (C) complex to the aPL antibody-mediated intravascular thrombosis. In conclusion, our data indicate that antibodies to beta2-glycoprotein I trigger coagulation subsequent to a priming proinflammatory factor and that the terminal C complex is the main mediator of the coagulation process
Prevention of arthritis by locally synthesized recombinant antibody neutralizing complement component C5
No full textTreatment of patients suffering from chronic diseases such as rheumatoid arthritis with recombinant antibodies is time consuming and fairly expensive and can be associated with side effects due to generalized depletion of the target molecule. We have addressed these issues by developing an alternative approach consisting of the intraarticular injection of a DNA vector encoding for the anti-C5 neutralizing recombinant miniantibody MB12/22. This method allows local production of the antibody in sufficient amount to be effective in preventing joint inflammation in a rat model of antigen-induced arthritis. Injection of the DNA vector in a right knee of normal rats resulted in the production of the minibody detected in the synovial washes by western blot with a strong signal peaking at 3 days after administration. DNA encoding for the minibody was shown for 14 days in the synovial tissue and was undetectable in the controlateral knee and in other organs. The preventive effect of this approach was evaluated in rats receiving a single injection of the vector 3 days before the induction of antigen-induced arthritis and analyzed 3 days later. The treated rats exhibited a lower increase in swelling, associated with a lower number of PMN in the articular washes and reduced deposition of C9 in synovial tissue compared to control rats. These results suggest that treating the inflamed joints with a vector that induces a local production of a neutralizing anti-C5 antibody may represent a useful strategy to inhibit in situ complement activation and to treat patients with monoarthritis. Moreover, this approach may be adopted as a novel therapeutic strategy to prevent monoarthritis as an alternative to local treatment with antibodies commonly used in this form of arthritis, with the advantages of the lower cost and the longer persistence of antibody production
Attenuation of apoptosis-induced ischemia/reperfusion injury by a novel scFV anti-C5 antibody in heterotopic rat heart transplantation
No full textOsteoprotegerin increases leukocyte adhesion to endothelial cells both in vitro and in vivo
No full textRecombinant osteoprotegerin (OPG) promoted the adhesion of both primary polymorphonuclear neutrophils (PMNs) and leukemic HL60 cells to endothelial cells. Leukocyte/endothelial cell adhesion was promoted by short (peak at 1 hour) preincubation of either endothelial cells or PMNs with OPG, and the peak of proadhesive activity was observed in the same range of OPG concentrations detected in the sera of patients affected by cardiovascular diseases. Although the cognate high-affinity ligands for OPG, membrane receptor activator of nuclear factor-kappaB ligand (RANKL) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), were detected at significant levels on both PMNs and HL60 cells, they were not expressed on the surface of endothelial cells. However, preincubation of OPG with heparin abrogated its proadhesive activity, whereas pretreatment of endothelial cells with chondroitinase plus heparinases significantly decreased the proadhesive activity of OPG. Taken together, these findings suggest the involvement of both the ligand binding and the N-terminal heparin-binding domains of OPG in mediating its pro-adhesive activity. The relevance of these in vitro findings was underscored by in vivo experiments, in which the topical administration of recombinant OPG increased leukocyte rolling and adhesion to rat mesenteric postcapillary venules. Our data suggest that a pathological increase of OPG serum levels might play an important role in promoting leukocyte/endothelial cell adhesion
Osteoprotegerin increases leukocyte adhesion to endothelial cells both in vitro and in vivo.
No full textRecombinant osteoprotegerin (OPG) promoted the adhesion of both primary polymorphonuclear neutrophils (PMNs) and leukemic HL60 cells to endothelial cells. Leukocyte/endothelial cell adhesion was promoted by short (peak at 1 hour) preincubation of either endothelial cells or PMNs with OPG, and the peak of proadhesive activity was observed in the same range of OPG concentrations detected in the sera of patients affected by cardiovascular diseases. Although the cognate high-affinity ligands for OPG, membrane receptor activator of nuclear factor-kappaB ligand (RANKL) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), were detected at significant levels on both PMNs and HL60 cells, they were not expressed on the surface of endothelial cells. However, preincubation of OPG with heparin abrogated its proadhesive activity, whereas pretreatment of endothelial cells with chondroitinase plus heparinases significantly decreased the proadhesive activity of OPG. Taken together, these findings suggest the involvement of both the ligand binding and the N-terminal heparin-binding domains of OPG in mediating its pro-adhesive activity. The relevance of these in vitro findings was underscored by in vivo experiments, in which the topical administration of recombinant OPG increased leukocyte rolling and adhesion to rat mesenteric postcapillary venules. Our data suggest that a pathological increase of OPG serum levels might play an important role in promoting leukocyte/endothelial cell adhesion
Innate immunity, through late complement components activation, contributes to the development of early vascular inflammation and morphologic alterations in experimental diabetes.
No full textTo verify if innate immunity, and namely the assembly of terminal complement complex (TCC) could be involved in the development of early diabetic vascular damage.At first in 2 groups of diabetic or non-diabetic Wistar rats the occurrence of basal or stimulated stable adherence to the endothelial layer and extravasation of circulating fluorescently-labelled leukocytes was assessed by using an in vivo videomicroscopy technique. In a second part of the study, the development of vascular damage in short term diabetes was studied in the genetically C6 deficient rats of the PVG strain, and compared with those observed in the wild-type C6 sufficient animals. Here, the analysis of mesentery vascular expression of mRNA for vascular cell adhesion molecule (VCAM)-1, transforming growth factor-β (TGF-β), connective tissue growth factor (CTGF), and platelet-derived growth factor (PDGF), the evaluation of intravascular protein levels of VCAM-1, TGF-β, CTGF, proliferative cell nuclear antigen (PCNA), as well as the assessment of structural changes and Complement components deposition at the mesentery arterial vascular wall were also performed.Leukocyte trafficking, mesentery arteries hypertrophy, extracellular matrix deposition, local vascular gene and protein expression of VCAM-1, TGF-β, CTGF and PCNA, as well as PGDF gene expression were all increased by short term diabetes, but all significantly reduced in the C6 deficient diabetic animals, thus suggesting an active role for TCC in the development of vascular inflammation in the early phases of experimental diabetes
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