Sputum leukotrienes in obstructive airways diseases.

Area of Science:

• Biochemistry
• Pulmonology
• Immunology

Background:

• Leukotrienes are inflammatory mediators implicated in obstructive airways diseases.
• Previous studies suggest SRS-A leukotrienes (LTC4, LTD4) play a role in asthma pathogenesis.

Purpose of the Study:

• To investigate the presence and biological activity of leukotrienes B4, C4, and D4 in sputum from patients with bronchial asthma, chronic bronchitis, and cystic fibrosis.
• To compare the levels and characteristics of these leukotrienes across different obstructive airways diseases.

Main Methods:

• Sputum samples were analyzed for leukotrienes using ethanol extraction and purification on Amberlite XAD-8.
• High-performance liquid chromatography (HPLC) was used for leukotriene identification.
• Biological activity was assessed using the Boyden chemotaxis assay and guinea-pig ileum contraction assay.

Main Results:

• Leukotriene B4 (LTB4) was detected in all sputum samples from patients with bronchial asthma, chronic bronchitis, and cystic fibrosis.
• SRS-A leukotrienes (LTC4/LTD4) were detected in cystic fibrosis and chronic bronchitis sputum but were largely absent in bronchial asthma sputum.
• Anaphylatoxin-like substances were found in a significant proportion of asthmatic sputum samples.

Conclusions:

• Lipoxygenase products of arachidonic acid metabolism are present in sputum in various obstructive airways diseases.
• The absence of detectable SRS-A leukotrienes in bronchial asthma sputum may be due to extraction losses, assay insensitivity, or rapid catabolism by bronchial secretions.
• Further research is needed to elucidate the precise role and metabolism of leukotrienes in different obstructive lung diseases.