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Background Platelet-activating factor (PAF) is a highly potent phospholipid mediator responsible for the life-threatening manifestations of anaphylaxis. PAF acetylhydrolase (PAF-AH) inactivates PAF and protects against severe anaphylaxis whereas deficiency of PAF-AH predisposes to severe or fatal anaphylaxis. Determinants of PAF-AH activity have not been studied in patients with peanut allergy. Objectives To determine whether plasma PAF-AH activity in patients with peanut allergy is related to formation of circulating complexes with apolipoprotein B (apoB) the main surface protein on low density lipoprotein particles. Methods Plasma PAF-AH activity and apoB concentrations were measured in 63 peanut allergic patients (35 boys, 28 girls, ages 2 - 19 years). ApoB concentration was measured immunoturbidimetrically using goat anti-human apoB. The correlation between PAF-AH activity and apoB concentration was determined. Results A positive correlation was found between PAF-AH activity and apoB concentration (r² = 0.59, P < 0.0001). Conclusion In peanut allergic patients, PAF-AH activity strongly correlates with apoB concentration, suggesting the presence of circulating PAF-AH- lipoprotein complexes. [ABSTRACT FROM AUTHOR]

Highlights: [•] IL-1β induces a time dependent synthesis of intracellular PAF in U-937. [•] The last enzymes of both biosynthetic routes of PAF are activated by IL-1β. [•] PAF-AH is crucial for the maintenance of intracellular PAF levels in U-937. [ABSTRACT FROM AUTHOR]

Background: Platelet-activating factor (PAF) is a potent bioactive phospholipid, which may be one of the determinants of atherogenesis. The purpose of this study was to investigate the relationship between the concentrations of plasma platelet-activating factor and age in a common Chinese population. Methods: Two-hundred seventy-nine Han nation subjects (male: n=162; female: n=117) who had visited two hospitals for overall health survey, as an annual medical check-up or for other reasons by clinical examinations were recruited and divided into six age groups (21–30, 31–40, 41–50, 51–60, 61–70, 71–80 years). PAF was extracted from their plasma and purified by thin-layer chromatography (TLC). The PAF concentrations were detected by radioimmunoassay. Results: The PAF concentrations (pg/ml) in plasma showed significantly age-related increase (r=0.3348, P<0.01, n=279). In the 21–30-year group, the PAF concentration was 338±96 pg/ml. Except for the 31–40-year group, the PAF concentrations in other four groups were all higher than that of the 21–30-year group (P<0.05, P<0.01, P<0.001 and P<0.001, respectively). Conclusions: Considering PAF is one of the key factors relevant to progression of atherogenesis, and the high concentrations of plasma PAF may therefore serve as a marker for the risk of atherosclerosis. Adjustment of the concentrations of plasma PAF correlated with aging may be helpful to reducing the prevalence rate of multi-senile arteriosclerosis occlusive diseases. [Copyright &y& Elsevier]