Arachidonate 5-Lipoxygenase Metabolism in Human Neutrophils from Patients with Asthma: In vitro Effect of Nedocromil Sodium

Abstract

Among the cells which participate in amplification of the local inflammatory reaction in asthma, neutrophils (PMN) are pro-inflammatory cells that can generate inflammatory mediators and arachidonic acid derivatives in particular. In asthmatic patients (AP) with attacks, the capacity of blood PMN to produce 5-lipoxygenase metabolites was investigated and compared to the response in healthy subjects (HS). PMN from 6 AP and from 6 HS were stimulated by calcium ionophore A23187 and arachidonate 5-lipoxygenase metabolites were analyzed by reverse-phase HPLC. LTB₄, 6-trans LTB₄, ωOH-LTB₄ and 5-HETE were identified. In AP, total LTB₄ synthesis was enhanced as compared to synthesis with PMN in HS. But the total 5-HETE synthesis by PMN from AP was decreased. Thus, the inflammatory potential of PMN from AP was enhanced in comparison to HS. The anti-inflammatory effect of nedocromil sodium (NS) was studied in the 5-lipoxygenase metabolism of arachidonic acid. NS (10^––⁴ mol/l) inhibited total LTB₄ synthesized by PMN in AP but not in HS. We conclude that NS affects leukotriene synthesis only in cells with enhanced inflammatory potential.

A Method for the Measurement of Plasma Hydroxyeicosatetraenoic Acid Levels

“…In addition, a strong viral promoter may interfere with expression of the test promoter. It has been reported that the presence of different plasmids may produce significant variations in the expression level of the control plasmid, sometimes enhancing expression and other times reducing expression (2)(3)(4). To provide a more unbiased measure of transfection efficiency, direct measures of transfection efficiency for the same test plasmid have been described by using Southern blotting (5) and fluorescence in situ hybridization (FISH) (6).…”

“…Blood cells from patients with inflammatory disorders are hyperreactive compared to those from healthy subjects, since they generate higher levels of reactive oxygen species and arachidonic acidderived mediators (2)(3)(4)(5)(6)(7). It would be of potential interest to find a biomarker, associated with the disease severity, and related to the ongoing of inflammation process in diseases such as asthma and rheumatoid arthritis.…”

5(S),15(S)-dihydroxyeicosatetraenoic acid and lipoxin generation in human polymorphonuclear cells: dual specificity of 5-lipoxygenase towards endogenous and exogenous precursors.

“…~Abbrev/at/ans used m ~ pa~: AM, alveolar macrophagerg 5-HETE, 5(S)hydroxyeicosatetraenoic acid; 12-HETE, 12(S)-hydroxyeicosate~aenoic aci& 15(S)-HETE, 15~q~ydroxyeic~no*c acid; 5(S),ISCS)-~HETE, 5(S),15(S)-dihydroxyeicosa~ic acid; 15(S)-HPETE, 15(S)--hydroperoxyeicosatetraenoic acid; LT, leukotnene; LTA4, 5(S)-5,6-oxido--I 1, 14cis-7,9-traas~eicosatelraenoic a~-id; LTB~, 5(S),i2(R)--dihydroxy--6,14-c/s-8,10-trans--eicosatetraenoic acid; LTC 4, 5(S),6(R)-5-hydroxy--6-(S-glutathionyl)-7,9-trans-I 1,14-as--eicosatetraenoic acid; LX, lipoxines; LXA4, (5S, 6R, 15S)-tfihydroxy -7,9,13-trans-ll-cis-eicosatetraenoic acid; 6S-LXA 4, (5S, 6S, 15S)-trihydroxy-7,9,13-trans-11 --ds--eicosateWaenoic acid; 11-trans-LX/~, (5S, 61~, lSS~-trJhydroxy-7,9,11,13-~rans-eicosatewaenoic acid; 6S-ll-trans-LXA4, (5S, 6S, 15S)-trihydroxy-7,9,11,13-trans-eicosatetraenoic acid; 7-ds-ll-trans-LXA 4, (5S, 6R, 15S)-trihydroxy-9,ll, 13-trans-7-ds--eicosatetraenoic acid; LXB4, (5S, 14R, 15S)-trihydroxy-6,10,12-trans-8--ds--eicosatetraenoic acid; 8--ttans-LXB4, (5S, 141~ 15S)trihydroxy-6,8,10,12-trans-eicosatetraenoic acid; 14S-8-trans-LXB4, (5S, t4S, 15S)-trilaydroxy-6,8,10,12-trans--eicosatewaenoic acid; RP-HPLC, re-verse~phase high performance liquid chromatography. studies demonstrated that 5-LO activity of PMN from patients with inflammatory diseases is enhanced as compared to 5-LO activity of cells from healthy subjects (controls) (7)(8)(9)(10). This high level of 5-LO activity may occur as a result of specific cellular activation due to cooperation with surrounding blood cells.…”

“…studies demonstrated that 5-LO activity of PMN from patients with inflammatory diseases is enhanced as compared to 5-LO activity of cells from healthy subjects (controls) (7)(8)(9)(10). This high level of 5-LO activity may occur as a result of specific cellular activation due to cooperation with surrounding blood cells.…”