The steroid effect on the in vitro human neutrophil chemotactic response

Treatment with rhDNase in patients with cystic fibrosis alters in-vitro CHIT-1 activity of isolated leucocytes

Recent data suggest a possible relationship between cystic fibrosis (CF) pharmacotherapy, Aspergillus fumigatus colonization (AC) and/or allergic bronchopulmonary aspergillosis (ABPA). The aim of this study was to determine if anti-fungal defence mechanisms are influenced by CF pharmacotherapy, i.e. if (1) neutrophils form CF and non-CF donors differ in their ability to produce chitotriosidase (CHIT-1); (2) if incubation of isolated neutrophils with azithromycin, salbutamol, prednisolone or rhDNase might influence the CHIT-1 activity; and (3) if NETosis and neutrophil killing efficiency is influenced by rhDNase. Neutrophils were isolated from the blood of CF patients (n = 19; mean age 26·8 years or healthy, non-CF donors (n = 20; 38·7 years) and stimulated with phorbol-12-myristate-13-acetate (PMA), azithromycin, salbutamol, prednisolone or rhDNase. CHIT-1 enzyme activity was measured with a fluorescent substrate. NETosis was induced by PMA and neutrophil killing efficiency was assessed by a hyphae recovery assay. Neutrophil CHIT-1 activity was comparable in the presence or absence of PMA stimulation in both CF and non-CF donors. PMA stimulation and preincubation with rhDNase increased CHIT-1 activity in culture supernatants from non-CF and CF donors. However, this increase was significant in non-CF donors but not in CF patients (P < 0·05). RhDNase reduced the number of NETs in PMA-stimulated neutrophils and decreased the killing efficiency of leucocytes in our in-vitro model. Azithromycin, salbutamol or prednisolone had no effect on CHIT-1 activity. Stimulation of isolated leucocytes with PMA and treatment with rhDNase interfered with anti-fungal defence mechanisms. However, the impact of our findings for treatment in CF patients needs to be proved in a clinical cohort.

Effect of dexamethasone on neutrophil accumulation and oedema formation in rabbit skin: an investigation of site of action

1. The anti-inflammatory actions of dexamethasone on vascular and leukocyte responses in rabbit skin were investigated. 2. Neutrophil accumulation and oedema formation were simultaneously measured as the local accumulation of i.v. administered 111In-labelled neutrophils and 125I-labelled albumin. Systemically administered dexamethasone (3 mg kg-1) inhibited neutrophil accumulation induced by i.d. zymosan activated plasma (ZAP), N-formyl-methionyl-leucyl-phenylalanine (FMLP) and leukotriene B4 (LTB4) when co-injected with prostaglandin E2 (PGE2). Dexamethasone also inhibited oedema formation elicited by these stimuli and the responses induced by i.d. platelet activating factor (PAF)+PGE2 and bradykinin (BK)+PGE2. 3. Intradermal dexamethasone (2 x 10(-10) mol per site) but not indomethacin (10(-8) mol per site) inhibited oedema formation induced by i.d. ZAP+PGE2 and BK+PGE2. This inhibitory effect of dexamethasone was significant only with pretreatment periods of 4 h, shorter pretreatment periods resulting in greatly reduced effects. Intradermal dexamethasone had no effect on neutrophil accumulation induced by ZAP+PGE2. 4. Intradermal dexamethasone (2 x 10(-10) mol per site) had no effect on increase in blood flow induced by PGE2 as measured by 133Xenon clearance. 5. The accumulation of neutrophils isolated from donor rabbits pretreated with i.v. saline or dexamethasone (3 mg kg-1) was investigated in untreated recipient rabbits. The accumulation of neutrophils, induced by ZAP+PGE2, FMLP+PGE2 and LTB4+PGE2, from dexamethasone-pretreated donors was significantly smaller than the accumulation of neutrophils from saline-pretreated donors. 6. The results of this study suggest that dexamethasone can have a direct effect on vascular endothelial cells resulting in an inhibition of oedema formation. 7. Neutrophil accumulation can be inhibited by an effect of dexamethasone on the neutrophil itself or on the vascular endothelium. These results indicate that at least part of the inhibitory effect is on the circulating neutrophil induced by dexamethasone or a dexamethasone-induced product.

Alteration of neutrophil (PMN) function by heparin, dexamethasone, and enalapril

The aim of this study is to investigate the effect of a seemingly divergent class of pharmacologic agents, each having been reported to suppress intimal hyperplasia, on neutrophil (PMN) function. Human PMNs were isolated and exposed for 30 min to either saline or one of three different pharmacologic agents, each tested at three different concentrations: Group 1, saline (control, n = 14); Groups 2-4, heparin (5000 units, n = 8; 2500 units, n = 6; 1250 units, n = 6) respectively; Groups 5-7, dexamethasone (4 mg, n = 8; 2 mg, n = 6; 1 mg, n = 6), respectively; and Groups 8-10, enalapril (1.25 mg, n = 8; 0.62 mg, n = 6; 0.31 mg, n = 6). Superoxide anion production was measured by the reduction of cytochrome c in a spectrophotometric assay. Chemotaxis was evaluated by the number of PMNs migrating across a filter using a Neuro Probe chamber. Phagocytosis was determined by the ingestion of opsonized zymosan particles by PMNs. Serum obtained from each PMN donor was used both to opsonize the zymosan and as a chemoattractant in the chemotaxis assay. No agent, at any dose, significantly changed superoxide production when compared to control cells. All three agents significantly inhibited PMN chemotaxis at every dose tested (P less than 0.01). In the phagocytosis assay, both heparin (at high and intermediate doses) and enalapril (at all doses) significantly reduced phagocytic activity (P less than 0.01); however, dexamethasone (at high and intermediate doses) produced a marked stimulation (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Antifungal drugs affecting the chemotaxis of polymorphonuclear neutrophils

Investigations on the chemotaxis of polymorphonuclear neutrophils (PMNs) towards a cytoplasmic extract of Trichophyton rubrum in the presence and absence of antifungal drugs are described. It is shown that with griseofulvin, clotrimazole, econazole, ketoconazole, miconazole and natamycin at 1 mg l(-1), the number of PMNs migrating was significantly reduced. After 3 h of exposure to 10 mg l(-1), not one of the drugs tested had any discernable effect on the viability of the PMNs, or the complement. The anti-inflammatory activity of the drugs is discussed and whilst the chemosuppression of PMN chemotaxis may be an undesirable feature in a drug used to treat systemic mycoses, it is unlikely to have any adverse effect in the therapy of the dermatophytoses.

Reduction by dexamethasone of chemotactic activity in inflammatory exudates

Using an experimental model for allergic inflammation of the air pouch type in rats, the effects of dexamethasone and indomethacin on leukocyte infiltration and level of chemotactic activity in the inflammatory exudate were examined to clarify the mechanisms of anti-inflammatory effects of glucocorticoids. Both dexamethasone and indomethacin when locally administered inhibited leukocyte infiltration, while chemotactic activity of the exudate was reduced by dexamethasone only. Indomethacin failed to reduce the level of chemotactic activity. Suppression by dexamethasone of the level of chemotactic activity became evident prior to the decrease in the number of leukocytes in the inflammatory exudate. These results suggest that the anti-inflammatory steroids manifest their inhibitory effect on leukocyte infiltration by inhibiting the generation of chemotactic factors in the inflammatory site. Besides this, the possible production of some inhibitory factors by the steroids may be considered as an alternative mechanism.

Chemotactic factor production by rat polymorphonuclear leukocytes: stimulation with opsonized zymosan particles and inhibition by dexamethasone

Rat polymorphonuclear leukocytes exposed to opsonised zymosan particles in vitro instantaneously and continuously release a chemotactic factor in the medium. The activity of this factor was mainly attributed to leukotriene B4, based on the data with high performance liquid chromatography. Preincubation of the cells with an antiinflammatory steroid, dexamethasone, at a dose of 0.25 micrograms/ml caused suppression in generation of the chemotactic factor from the leukocytes in a time-dependent manner.

The effect of epicutaneous glucocorticosteroids on human monocyte and neutrophil migration in vivo

The effect of epicutaneous methyl prednisolone (MP) at 10-4, 10-5, and 10-6 molar concentration was studied in 54 normal, healthy volunteers using a new, in vivo microchemotaxis technique. Significant inhibition of monocyte chemotaxis occurred at all concentrations studied and persisted over a 24-hr period with 10-4 molar MP. Neutrophil chemotaxis was significantly inhibited only with 10-4 MP. The inhibitory effect of MP on neutrophil and monocyte chemotaxis occurred earlier and at lower concentrations if the skin sites were pretreated with steroid. Thus, when corticosteroids are applied on abraded skin in concentrations achievable in vivo, monocyte chemotaxis into tissue is inhibited for longer periods and at lower drug concentrations than is neutrophil chemotaxis. By avoiding the significant systemic effects of corticosteroids on circulating monocyte and neutrophil populations, these experiments establish that local inhibition of chemotaxis is an important anti-inflammatory effect of corticosteroids, with differential effect on monocytes and neutrophils.

Effect of high-dose methylprednisolone infusion on polymorphonuclear leukocyte function in patients with systemic lupus erythematosus

We have studied the effect of high-dose (1 gm) methylprednisolone infusion on polymorphonuclear leukocyte (PMN) function in 11 patients with active systemic lupus erythematosus (SLE). The only alteration of polymorphonuclear leukocyte function produced consistently by methylprednisolone was decreased adherence to plastic surfaces when tested 2 hours after infusion. This steroid-induced abnormality, however, was transient. Cells obtained from patients 24 hours after a single dose of drug exhibited normal adhesiveness. These results indicate that single, large doses of methylprednisolone do not produce long-lasting abnormalities of PMN function in patients with lupus.

Effect of one gold salt, of betamethasone, and of aspirin on the chemotaxis of human neutrophils measured in vitro

The effects of 1 gold salt, of betamethasone, and of acetylsalicylate on the chemotaxis of human neutrophils were compared in normal volunteers by means of a modified Boyden chamber. The gold salt inhibited chemotaxis by reducing both cell migration capacity and the capacity of plasma to attract the cell. Betamethasone reduced cell migration capacity, but not the chemoattractant capacity of plasma. Acetylsalicylate had no effect on these functions.

Prolactin suppression of leukocyte chemotaxis in vitro

Leukocyte chemotaxis in vitro was studied for cells from patients with pituitary adenomas. Leukocytes obtained preoperatively from two of three patients with elevated serum prolactin levels demonstrated chemotaxic alterations described in other malignant disease. Statistically significant suppression of chemotaxis occurred in the leukocytes of four of 12 specimens from normal donors at concentrations of 1000 ng/ml, and in four of eight specimens at 2000 ng/ml of prolactin in preincubation media. Thus prolactin concentration may influence the motility of leukocytes. The variable neoplastic behavior of morphologically similar pituitary adenomas may, in part, reflect a neurohormonally altered host response to the presence of these lesions.

Steroids, aspirin, and inflammation

The ability of adrenal corticosteroids to both both suppress inflammation and compromise host defenses has been well documented. Recently, a series of in vitro and in vivo experiments, based on our new knowledge of the cell biology of inflammation and the biochemistry of the phagocytic cell itself, has provided new insights into the mechanism of steroid action in the inflammatory process. Evidence is presented that pharmacologic doses of steroids are capable of inhibiting each of the steps in phagocytic-micro-organism interaction: chemotaxis, recognition and opsonization, phagocytosis, membrane fusion, and degranulation. In addition, steroid alteration of the postphagocytic superoxide production, hydrogen peroxide generation, and prostaglandin and thromboxane synthesis is described. The antiinflammatory effects of aspirin and indomethacin can be explained almost entirely by virtue of their ability to inhibit cyclooxygenase, this preventing the transformation of arachidonic acid to both prostaglandins and thromboxanes. The cortisol-induced inhibition of endoperoxides, prostaglandins, and thromboxanes (at a site proximal to the release of arachidonic acid) may well explain those antiinflammatory actions that cortisone shares with aspirin. However, patients treated with nonsteroidal antiinflammatory agents effectively combat infections. In contrast, corticosteroids have more profound effects, as can be seen by the inhibition of superoxide production, with the subsequent decrease in hydrogen peroxide generation and the diminution in release of the antibacterial lysosomal hydrolases within the phagocytic vacuole. Thus, corticosteroids interfere with the killing of microorganisms. This new understanding of the pharmacologic action of cortisol on phagocytic cells explains, we believe, how glucocorticoids alleviate inflammation while, at the same time, they permit multiplication of the offending microorganism within the phagocyte.

Functional capabilities of steroid-recruited neutrophils harvested for clinical transfusion

To determine whether steroids exert a direct inhibitory effect on neutrophil function, thus contraindicating their use to increase granulocyte yields for white-cell transfusions to infected neutropenic patients, we gave normal donors a single intravenous dose of dexamethasone (4 mg per square meter of body-surface area). Approximately two hours later the absolute neutrophil count increased from an initial value (mean +/- 1S.D.) of 3800 +/- 1400 to 5700 +/- 2400 per microliter. Granulocytes were then collected by discontinuous-flow centrifugation and tested. Viability (98.4 per cent), the percentage of neutrophils capable of phagocytosis (97.6), particle accumulation (12.3 candida per phagocyte), fungicidal activity (1.08 "ghost" yeast cells per phagocyte), the percentage of bacteria killed (97.7) and chemotaxis (119 per cent) did not significantly differ from observations in nontreated paired controls. The functional competence of neutrophils used for granulocyte transfusions was not altered after short-term exposure of these healthy donors to steroid medication.