Effects of smoking cessation and nicotine substitution on systemic eicosanoid production in man

This study investigated the effects of smoking cessation with and without n icotine substitution on the excretion of major urinary metabolites of throm boxane A(2) and prostacyclin, 11-dehydrothromboxane B-2 and 2,3-dinor-6-ket oprostaglandin F1(alpha), respectively, as well as on the, excretion of leu kotriene E-4 in man. Urine samples were, obtained from 20 healthy non-smoki ng controls and from 60 healthy smoking volunteers before, and 3, 7 and 14 days after smoking cessation. Fifteen smokers quit smoking without nicotine substitution, 15 used nicotine chewing gum and 30 used nicotine patches as a substitution therapy, Urinary thiocyanate as well as cotinine and trans- 3'-hydroxycotinine excretions were used as compliance and nicotine substitu tion indicators. 11-Dehydrothromboxane B-2, 2,3-dinor-6-ketoprostaglandin F-1 alpha and leuk otriene E-4 after smoking cessation. Fifteen smokers quit smoking without e xcretion was about two, three and five times higher in smokers than in cont rols, respectively. Three days after smoking cessation without nicotine sub stitution. 11-dehydrothrombosane B-2 and 2,3-dinor-6-ketoprostaglandin F-1 alpha levels were lowered to 75% (P <0.01) and 80% (P <0.05) of the initial values, and after 14 days to 50% (P <0.01) and 60% (P <0.05), respectively . Tn 3 days leukotriene E-4 excretion was dropped to 78% of the initial val ue (P <0.05), but no ful ther decrease was observed during the study, In in dividuals using nicotine chewing gum or nicotine patches no significant cha nges were observed in the analytes during the 2-week follow-up? The increas ed systemic eicosanoid synthesis observed in smokers may be involved in the harmful cardiovascular effects of smoking, The: fact that eicosanoid produ ction remains at pre-cessation level in volunteers who quit smoking but use nicotine substitution may be involved in the risk of cardiovascular compli cations reported during nicotine replacement therapy.