| 1. |
- Zhang, X W, et al.
(författare)
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Important role of CD18 in TNF-alpha-induced leukocyte adhesion in muscle and skin venules in vivo
- 2000
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Ingår i: Inflammation Research. - : Springer Science and Business Media LLC. - 1420-908X .- 1023-3830. ; 49:10, s. 529-534
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To examine the role of CD 18 in tumor necrosis factor-alpha (TNF-alpha)-induced leukocyte adhesion and extravasation in vivo. MATERIAL: Male wild-type (WT) and mutated mice with hypomorphic expression of CD 18. METHODS: Intravital microscopy was used to quantitate leukocyte-endothelium interactions provoked by TNF-alpha (0.5 microg) in the cremaster muscle and dorsal skin microcirculation. Tissue recruitment of leukocytes was evaluated in wholemounts of the cremaster muscle and in air pouches in the dorsal skin after TNF-alpha stimulation. RESULTS: TNF-alpha markedly increased venular leukocyte adhesion and recruitment in the cremaster muscle and skin in WT. Notably, in CD 18-targeted animals, leukocyte adhesion triggered by TNF-alpha challenge was significantly reduced by 58% and 72% in venules of the cremaster muscle and skin, respectively. Moreover, in CD18-mutants, tissue accumulation of polymorphonuclear leukocytes (PMNLs) provoked by TNF-alpha in the muscle and skin was decreased by 84% and 70%, respectively. Interestingly, the observed level of reduction in TNF-alpha-induced neutrophil adhesion and recruitment in CD18 gene-targeted animals corresponded well with the decrease in CD 18 expression on neutrophils from these mice, i.e. the surface density of CD18 was reduced by 77% in mutants compared to WT. Differential analysis revealed that the extravascular leukocytes comprised more than 90% PMNLs, indicating that neutrophils were the main inflammatory cell responding to TNF-alpha activation. Notably, the expression of CD18 increased by more than two-fold on extravasated neutrophils compared to circulating neutrophils in the peripheral blood both in WT and mutant animals. CONCLUSIONS: These findings suggest that CD18 is a dominant mediator of firm neutrophil adhesion to venular endothelial cells in the muscle and skin stimulated by TNF-alpha in vivo. In addition, this decreased adhesion in CD18-mutants attenuates leukocyte extravasation in response to TNF-alpha activation. Thus, inhibition of CD 18-function may provide an important strategy to inhibit leukocyte recruitment in cytokine-dependent diseases.
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| 2. |
- Li, Xiang, et al.
(författare)
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Interleukin-10 mediates the protective effect of Linomide by reducing CXC chemokine production in endotoxin-induced liver injury
- 2004
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Ingår i: British Journal of Pharmacology. - : Wiley. - 1476-5381 .- 0007-1188. ; 143:7, s. 865-871
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Tidskriftsartikel (refereegranskat)abstract
- 1 The immunomodulator Linomide has been shown to protect against septic liver injury by reducing hepatic accumulation of leukocytes although the detailed anti-inflammatory mechanisms remain elusive. This study examined the effect of Linomide on the production of CXC chemokines, including macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (KC) and interleukin-10 (IL-10) in lipopolysaccharide (LPS)/D-galactosamine (Gal)-induced liver injury in mice. 2 It was found that pretreatment with 300 mg kg(-1) of Linomide markedly Suppressed leukocyte recruitment, perfusion failure, and hepatocellular damage and apoptosis in the liver of endotoxemic mice. 3 Administration of Linomide inhibited endotoxin-induced gene expression of MIP-2 and KC and significantly reduced the hepatic production of MIP-2 and KC by 63 and 80%, respectively. Moreover, it was found that Linomide increased the liver content of IL-10 by more than three-fold in endotoxemic mice. 4 The protective effect of Linomide against endotoxin-induced inflammation and liver injury was abolished in IL-10-deficient mice, suggesting that the beneficial effect of Linomide is dependent on the function of IL-10. 5 Taken together, these novel findings suggest that the protective effect of Linomide is mediated via local upregulation of IL-10, which in turn decreases the generation of CXC chemokines and pathological recruitment of leukocytes in the liver of endotoxemic mice.
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| 3. |
- Li, Xiang, et al.
(författare)
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Lymphocyte function antigen-1 mediates leukocyte adhesion and subsequent liver damage in endotoxemic mice
- 2004
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Ingår i: British Journal of Pharmacology. - : Wiley. - 1476-5381 .- 0007-1188. ; 141:4, s. 709-716
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Tidskriftsartikel (refereegranskat)abstract
- 1 Sepsis is associated with leukocyte activation and recruitment in the liver. We investigated the role of lymphocyte function antigen-1 (LFA-1) in endotoxin-induced leukocyte-endothelium interactions, microvascular perfusion failure, hepatocellular injury and apoptosis in the liver by use of gene-targeted mice, blocking antibodies and a synthetic inhibitor of LFA-1 (LFA703). For this purpose, mice were challenged with lipopolysaccharide (LPS)+D-galactosamine (Gal), and intravital microscopy of the liver microcirculation was conducted 6 h later. 2 The number of Firmly adherent leukocytes in response to LPS/Gal was reduced by 48% in LFA-1-deficient mice. Moreover, endotoxin-induced increases of apoptosis and enzyme markers of hepatocellular injury were decreased by 64 and 69-90%, respectively, in LFA-1-deficient mice. Furthermore, sinusoidal perfusion was improved in endotoxemic mice lacking LFA-1. 3 A similar protective pattern was observed in endotoxemic mice pretreated with an antibody against LFA-1. Thus, immunoneutralization of LFA-1 reduced endotoxin-induced leukocyte adhesion by 55%, liver enzymes by 64-66% and apoptosis by 42%, in addition to the preservation of microvascular perfusion. 4 Administration of a novel statin-derived inhibitor of LFA-1, LFA703, significantly decreased leukocyte adhesion (more than 56%) and the subsequent liver injury in endotoxemic mice. 5 Thus, this study demonstrates a pivotal role of LFA-1 in supporting leukocyte adhesion in the liver. Moreover, interference with LFA-1-mediated leukocyte adhesion protects against endotoxemic liver damage, and may constitute a potential therapeutic strategy in sepsis.
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| 4. |
- Mangell, Peter, et al.
(författare)
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Critical role of P-selectin-dependent leukocyte recruitment in endotoxin-induced intestinal barrier dysfunction in mice.
- 2007
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Ingår i: Inflammation Research. - : Springer Science and Business Media LLC. - 1420-908X .- 1023-3830. ; 56:5, s. 189-194
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To define the importance of leukocyte recruitment in endotoxin-induced gut permeability. Materials and methods: 31 male C57BL/6 mice were challenged with lipopolysaccharide (LPS). Ileal permeability was measured in Ussing chambers and leukocyte-endothelium interactions studied with intravital fluorescence microscopy after 18 h. Results: LPS caused a clear-cut increase in leukocyte accumulation and intestinal permeability. Immunoneutralisation of P-selectin not only reduced leukocyte recruitment significantly (54% reduction) but also abolished endotoxin-induced intestinal leakage. Intestinal levels of pro-inflammatory chemokines increased markedly in response to LPS but were not influenced by inhibition of P-selectin in vivo. Conclusion: The present study shows not only that endotoxin-induced leukocyte recruitment is mediated by P-selectin but also that sepsis-associated intestinal leakage in the gut is largely regulated by leukocyte accumulation. Thus, our novel data demonstrate a critical link between P-selectin-dependent leukocyte recruitment and gut barrier failure in endotoxemia.
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| 5. |
- Menger, MD, et al.
(författare)
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Experimental models to study microcirculatory dysfunction in muscle ischemia-reperfusion and osteomyocutaneous flap transfer
- 2003
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Ingår i: Langenbeck's Archives of Surgery. - : Springer Science and Business Media LLC. - 1435-2451 .- 1435-2443. ; 388:5, s. 281-290
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Tidskriftsartikel (refereegranskat)abstract
- Background. During the past decade, experimental studies have provided convincing evidence that microcirculatory dysfunction plays a pivotal role in the manifestation of tissue injury in ischemia-reperfusion and osteomyocutaneous flap transfer. The study of the mechanisms of injury, however, requires sophisticated experimental in vivo models. With the use of microsurgical techniques, osteomyocutaneous flap transfer can successfully be performed in rat hind limbs, allowing in vivo fluorescent microscopic analysis of post-ischemic microcirculatory dysfunction in all tissues involved, including periosteum, striated muscle, subcutis and skin. The drawback of this "acute" model is that the period of analysis is restricted to a few hours only. Method. To overcome this limitation, the "chronic" dorsal skinfold chamber preparation, containing striated muscle and subcutis, can be used. This model allows one to study microcirculatory dysfunction after both tourniquet-induced and pressure-induced ischemia-reperfusion-induced tissue injury over a period of up to 3 weeks. Results. With the use of these models, recent investigations have demonstrated that ischemia-reperfusion and osteomyocutaneous flap transfer are associated with capillary perfusion failure (no-reflow), mediated by intravascular hemoconcentration, endothelial swelling and endothelin (ET)-1-mediated microvascular constriction. In addition, post-ischemic reperfusion provokes an inflammatory response (reflow paradox) in post-capillary venules, which is characterized by beta(2)-integrin-mediated and intercellular adhesion molecule (ICAM)-1-mediated leukocyte adhesion and vascular hyperpermeability, which results in interstitial edema formation. Treatment studies have produced evidence that isovolemic hemodilution and heat shock protein induction are successful in ameliorating capillary no-reflow, while blockade of adhesion molecules, inactivation of oxygen radicals and, also, induction of heat shock proteins, are capable of reducing the post-ischemic inflammatory response. Conclusion. These experimental results not only demonstrate the importance of the use of advanced in vivo methods to delineate pathophysiological mechanisms in complex disease models, but may also provide a basis for potential prospective randomized trials to test the benefit for the patient in the daily clinical routine.
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| 6. |
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| 7. |
- Riaz, AA, et al.
(författare)
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Role of angiotensin II in ischemia/reperfusion-induced leukocyte-endothelium interactions in the colon
- 2004
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Ingår i: FASEB Journal. - : Wiley. - 1530-6860 .- 0892-6638. ; 18:3, s. 881-881
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Tidskriftsartikel (refereegranskat)abstract
- The aims of the present study were to determine the effects and mechanisms of angiotensin II (Ang II) on leukocyte-endothelium interactions and the role of Ang II in a novel model of ischemia/reperfusion (I/R) in the mouse colon. Ang II dose-dependently increased leukocyte rolling and adhesion in colonic venules. Importantly, Ang II-induced leukocyte rolling was completely inhibited by immunoneutralization of P-selectin, and leukocyte adhesion was abolished in lymphocyte function antigen-1 (LFA-1)-deficient mice. The P-selectin-dependent rolling was found to be a precondition for the subsequent LFA-1-dependent leukocyte adhesion. Moreover, Ang II-induced leukocyte responses involved generation of reactive oxygen species and up-regulation of CXC chemokines. Notably, CXC chemokines, but not Ang II, stimulated leukocyte chemotaxis in vitro. I/R increased gene expression of angiotensin converting enzyme (ACE) in the colon and plasma concentrations of Ang II. Inhibition of ACE and the type 1 angiotensin (AT(1)) receptor significantly decreased the I/R-induced leukocyte adhesion. Taken together, these novel findings demonstrate that Ang II exerts potent pro-inflammatory effects in the colonic microcirculation and that inhibition of Ang II expression or function protects against I/R-induced leukocyte responses in the colon. Thus, it is suggested that Ang II is a major target to control pathological inflammation in the colon.
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| 8. |
- Roller, Jonas, et al.
(författare)
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Direct in vivo observations of P-selectin glycoprotein ligand-1-mediated leukocyte-endothelial cell interactions in the pulmonary microvasculature in abdominal sepsis in mice.
- 2013
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Ingår i: Inflammation Research. - : Springer Science and Business Media LLC. - 1420-908X .- 1023-3830. ; 62:3, s. 275-282
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: P-selectin glycoprotein ligand-1 (PSGL-1) has been shown to play a significant role in septic lung injury. However, the detailed role of PSGL-1 in the pulmonary leukocyte recruitment remains elusive. We have developed a method based on intravital fluorescence microscopy of the lung microcirculation to examine the role of PSGL-1 in the extravasation process of leukocytes in septic lung damage. METHODS: Male C57BL/6 mice were treated with a control antibody or an anti-PSGL-1 antibody prior to cecal ligation and puncture (CLP). Leukocyte-endothelium interactions and microvascular hemodynamics were studied in pulmonary arterioles, capillaries and venules 4 h after CLP. RESULTS: Immunoneutralization of PSGL-1 decreased CLP-induced leukocyte rolling in pulmonary arterioles and venules significantly. Inhibition of PSGL-1 had no effect on leukocyte adhesion in venules, whereas the number of adherent leukocytes in lung arterioles and the number of trapped leukocytes in capillaries were markedly decreased. Moreover, immunoneutralization of PSGL-1 improved microvascular perfusion in the lung of septic animals. CONCLUSIONS: Taken together, these results document that PSGL-1 mediates leukocyte rolling in arterioles and venules. However, inhibition of PSGL-1 only decreases leukocyte adhesion in arterioles, suggesting that leukocyte rolling is not a prerequisite for pulmonary venular adhesion of leukocytes in sepsis. In addition, our data show that capillary trapping of leukocytes is dependent on PSGL-1 function.
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| 9. |
- Santén, Stefan, et al.
(författare)
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P-selectin glycoprotein ligand-1 regulates chemokine-dependent leukocyte recruitment in colonic ischemia-reperfusion.
- 2007
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Ingår i: Inflammation Research. - : Springer Science and Business Media LLC. - 1420-908X .- 1023-3830. ; 56:11, s. 452-458
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Tidskriftsartikel (refereegranskat)abstract
- Objective and design: Leukocyte recruitment is a key feature in ischemia-reperfusion (I/R) -provoked tissue injury. This study evaluated the role of P-selectin-glycoprotein ligand-1 (PSGL-1) in CXC chemokine- and ischemia-reperfusion- induced leukocyte rolling and adhesion in the colon. Materials Balb/c mice were used in an inverted intravital fluorescence microscopy study of the microvascular bed in the colon. Treatment: Mice were challenged with macrophage inflammatory protein-2 (MIP-2) intraperitonally and leukocyte-endothelium interactions were analysed 3 h later. In separate experiments, mice were exposed to I/R by clamping of the superior mesenteric artery for 30 min and leukocyte rolling and adhesion were analysed after 120 min of reperfusion. Results: MIP-2 dose-dependently increased leukocyte rolling and adhesion in the colon. Pretreatment with an anti-PSGL-1 antibody reduced MIP-2-provoked leukocyte rolling and adhesion by more than 89%. I/R increased expression of MIP-2 as well as leukocyte rolling and adhesion. Immunoneutralization of PSGL-1 decreased reperfusion-induced leukocyte rolling by 85% and adhesion by 93% in colonic venules. Conclusions: Our data demonstrates that PSGL-1 is a dominant adhesion molecule supporting MIP-2- and I/R-provoked leukocyte rolling. Inhibition of PSGL-1 abolished leukocyte rolling and abrogated I/R-induced leukocyte adhesion in colonic venules. These findings suggest that targeting PSGL-1 may be an effective strategy to prevent I/R-induced inflammation in the colon.
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| 10. |
- Schramm, R, et al.
(författare)
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Leukocyte adhesion in aorta and femoral artery in vivo is mediated by LFA-1
- 2004
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Ingår i: Inflammation Research. - : Springer Science and Business Media LLC. - 1420-908X .- 1023-3830. ; 53:10, s. 523-527
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Cytokine-induced recruitment of leukocytes is an early feature during arterial injury and atherosclerotic plaque formation. The aim of this study was to analyze the role of the beta(2)-integrin lymphocyte function-associated antigen-1 (LFA- 1; CD11a/CD18) in cytokine-triggered firm leukocyte adhesion to arterial endothelium in vivo. Material and Methods: Intravital fluorescence microscopy was used to study leukocyte firm adhesion in the mouse aorta and femoral artery in response to combined local challenge with TNF-alpha and IL-1beta. Results: In wild-type (WT) mice, cytokine stimulation resulted in firm adhesion of 14.6 +/- 2.8 and 11.3 +/- 1.3 leukocytes/mm along the endothelium in the aorta and femoral artery (P < 0.05 vs. PBS-treated controls, n = 5-6). Notably, the number of firmly adherent leukocytes in aorta and femoral artery of cytokine-stimulated LFA-1-deficient animals was reduced by 54% and 92% indicating an important role of LFA-1 in leukocyte adhesion to arterial endothelium (P < 0.05 vs. controls, n = 5-6). In addition, pretreatment of WT mice with a monoclonal antibody (mAb) directed against murine LFA-1 attenuated the leukocyte adhesive response by 60% and 86% in aorta and femoral artery, respectively (P < 0.05 vs. control mAb-treated WT, n = 5-12). Conclusion: These novel data demonstrate that cytokine-induced firm leukocyte adhesion in the mouse aorta and femoral artery is LFA-1-dependent in vivo, which may implicate an important role for this β(2)-integrin leukocyte extravasation. in arterial injury and atherogenesis.
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