ABSTRACT
The aims of this study were to investigate the effects of Interleukin-8 (IL-8) and Growth related oncogene-alpha (Gro-alpha) on neutrophil apoptosis and determine the potential for a selective CXCR2 antagonist to inhibit these responses. IL-8 and Gro-alpha both produced dose dependent inhibition of spontaneous human neutrophil apoptosis after 16 hours incubation (59+/-3.5% and 27.5+/-3% respectively; EC50s 2.2+/-1.8 nM, and 0.5+/-0.2 nM respectively). The pro-survival effect of a fixed concentration of agonist (IL-8 or Gro-alpha) on cultured neutrophils was abrogated by a selective CXCR2 antagonist SB272844 (K(D)s 253 nM and 49.9 nM in the presence of IL-8 or Gro-alpha respectively). Our data suggests that the anti-apoptotic effect of Gro-alpha is mediated through CXCR2 as selective CXCR2 blockade with SB272844 can potently abrogate this response. The inhibitory effect of IL-8 may in addition partly be mediated through CXCR1 as SB272844 was less potent in its ability to abrogate the anti-apoptotic effects of IL-8 when this agent was used as an agonist. CXCR2 antagonists may have a therapeutic role in controlling neutrophil-driven inflammation by reducing neutrophil recruitment and restoring neutrophils to the tissue clearance pathway of apoptosis.
Subject(s)
Apoptosis/drug effects , Interleukin-8/physiology , Neutrophils/drug effects , Receptors, Interleukin-8A/antagonists & inhibitors , Receptors, Interleukin-8B/antagonists & inhibitors , Cells, Cultured , HumansABSTRACT
Cryptogenic fibrosing alveolitis (CFA) is characterized by increased pulmonary recruitment of peripheral blood neutrophils (PBNs) by interleukin (IL)-8 and other chemotactic mediators. This study investigated whether, in CFA, the PBN motility response is primed by IL-8 and growth-related oncogene (Gro)-alpha, as demonstrated in other neutrophilic inflammatory diseases, and whether the motility response of PBNs to IL-8 and Gro-alpha can be abrogated using a selective antagonist for the neutrophil receptor for IL-8 and Gro-alpha, CXCR2. The percentage of PBNs to undergo shape change (%SC), spontaneously and in response to IL-8 and Gro-alpha, was measured in patients with CFA (n=10) and controls (n=10), and the effect of the CXCR2 antagonist SB272844 studied. Plasma levels of IL-8, and Gro-alpha were measured using an enzyme-linked immunosorbent assay (ELISA). The %SC of unstimulated PBNs and the potency of Gro-alpha and IL-8 to produce neutrophil polarization was greater in CFA than in controls; dose which produces 50% of maximal effect (EC50) of IL-8 was 3.6 +/- 0.7 nM for CFA versus 6.3 +/- 1.0 nM for controls; p<0.05. SB272844 inhibited Gro-alpha induced but not IL-8 induced neutrophil shape change (equilibrium constant (KD) 123 +/- 18 nM). Plasma concentrations of Gro-alpha were increased in patients with CFA. PBNs are spontaneously activated and undergo a greater motility response to IL-8 and Gro-alpha in CFA. Interleukin-8 and growth-related oncogene-alpha, circulating in substimulatory amounts in cryptogenic fibrosing alveolitis, may prime the peripheral blood neutrophils motility response, thus increasing their capacity for migration to the lung. Selective CXCR2 antagonists may be useful to block the Gro-alpha-induced priming response whilst preserving neutrophil functions mediated by CXCR1, the alternative neutrophil receptor for interleukin-8.
Subject(s)
Chemokines, CXC/physiology , Chemotactic Factors/physiology , Growth Substances/physiology , Intercellular Signaling Peptides and Proteins , Interleukin-8/physiology , Lung Diseases, Interstitial/blood , Lung Diseases, Interstitial/physiopathology , Neutrophils/physiology , Aged , Chemokine CXCL1 , Chemotaxis, Leukocyte , Dose-Response Relationship, Drug , Female , Flow Cytometry , Humans , Male , Middle Aged , Receptors, Interleukin-8B/antagonists & inhibitorsABSTRACT
Hospital-based drug monitoring facilities have been used to investigate the frequency of perceptual disturbances in inpatients receiving pentazocine and the occurrence of dependence upon this drug after discharge from hospital. A pilot study was carried out in which seven out of 70 hospital inpatients receiving pentazocine reported such episodes, while in a prospective study, 9 out of 132 patients receiving pentazocine and 1 out of 112 receiving cyclimorph, dihydrocodeine, or pethidine reported their occurrence. A total of 135 patients who received pentazocine for disorders likely to require longterm analgesia were followed up for six months after their discharge from hospital. 24 had received pentazocine after discharge; two required an increase in dosage and four expressed a preference for pentazocine.
