Differential inhibition of polymorphonuclear leukocyte recruitment in vivo by dextran sulphate and fucoidan

The selectin-mediated rolling of leukocytes along the endothelial cells is a prerequisite step followed by firm adhesion and extravasation into the inflamed tissue. This initial contact can be suppressed by sulphated polysaccharides. We have studied the effect of sulphated polysaccharides on the ultimate polymorphonuclear leukocyte (PMN) recruitment and plasma leakage in rabbit skin in response to intradermal injection of various inflammatory mediators. PMN infiltration evoked by various PMN chemoattractants (FMLP, C5a desArg, LTB4 and IL-8) was significantly inhibited after intravenous injection of dextran sulphate (25 mg/kg), heparin (2 × 90 mg/kg) or fucoidan (1 mg/kg). PMN-dependent plasma leakage was equally well reduced by the different sulphated polymers. Vascular permeability induced by histamine or thrombin acting via a PMN-independent mechanism was not reduced. Fucoidan was the only polysaccharide able to suppress IL-1-induced PMN infiltration for 60–70%. Local administration of dextran sulphate had no effect on PMN-dependent plasma leakage. Differential inhibition of PMN recruitment was determined after injection of dextran sulphate or fucoidan depending on the type of insult. Therefore, these results suggest that different adhesion pathways are utilized during PMN recruitment in vivo in response to chemoattractants and IL-1

Increased microvascular permeability in vivo in response to intradermal injection of neutrophil-activating protein (NAP-2) in rabbit skin.

Neutrophil-activating protein-2 (NAP-2), an NH2-terminally processed form of the platelet-release product beta thromboglobulin (beta TG), was purified to homogeneity from stimulated human blood leukocytes. In the presence of a vasodilator substance (PGE2, CGRP) picomolar (pmol/l) amounts of NAP-2 induced neutrophil accumulation and plasma leakage on intradermal injection in rabbit skin, whereas the longer forms, beta TG itself and connective tissue-activating peptide III (CTAP-III), had no such effect. NAP-2-induced increased in microvascular permeability was neutrophil dependent and fast in onset, with a half-life of 65 to 75 minutes, comparable to that previously reported for the structural-related neutrophil-activating protein-1/interleukin-8 (NAP-1/IL-8). However NAP-2 showed a lower potency in that more protein was needed to provoke skin reactivity. Nevertheless the finding that a platelet release product can elicit neutrophil-mediated inflammation further narrows the gap between thrombotic events and inflammatory disorders

Evidence that inducible nitric oxide synthase is involved in LPS-induced plasma leakage in rat skin through the activation of nuclear factor-kB

IF 3,68