Increased cytokine release by leucocytes in survivors of stroke at young age.

BACKGROUND: Enhanced stimulus-induced release of pro-inflammatory cytokines by leucocytes may contribute to the pathogenesis of ischaemic stroke. DESIGN: We investigated the lipopolysaccharide-induced release of interleukin-1beta (IL-1beta), IL-6, IL-8, and tumour necrosis factor-alpha (TNF-alpha) in whole blood from 20 patients with a history of ischaemic stroke under the age of 50, 20 patients with a history of cervical artery dissection (CAD) and 21 age- and sex-matched healthy control subjects. RESULTS: Release of IL-8 was higher (P = 0.006) and release of TNF-alpha and IL-6 tended to be higher (P < 0.1) in young stroke patients than in control subjects. No increased release existed in CAD patients. Vascular risk factors or history of infection before stroke did not modify IL-8 production. A common T(250) --> A polymorphism in the IL-8 gene promotor was newly identified but did not correlate with the variability of IL-8 release. The C(260) --> T polymorphism in the gene of the monocytic LPS-receptor CD14--a risk factor for myocardial infarction--was not associated with increased cytokine release. CONCLUSIONS: We conclude that high inducible release of IL-8--and possibly of TNF-alpha and IL-6--may contribute to the odds of ischaemic stroke in young adults.

Cotinine effects on bile flow and biliary NNK elimination.

Nicotine and its major metabolite cotinine inhibit alpha-hydroxylation of the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) suggesting that an alternative pathway of NNK metabolism and elimination, biliary excretion of the O-glucuronide of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL-Gluc) may be enhanced. To verify the possible role of cotinine on biliary elimination of NNK and its metabolites, bile duct cannulated rats were administered a single i.p. dose of 50 mg/kg [56sup;-3 H]-NNK with or without i.p. co-administration of 5 mg/kg cotinine or nicotine. Cotinine significantly reduced cumulative bile flow and biliary elimination of NNK-derived radioactivity within six hours to 42 and 27 percent, respectively. The pattern of NNK metabolites in bile was unchanged. Nicotine had a similar inhibitory effect on bile flow. This result constitutes the first experimental evidence that cotinine inhibits bile flow. In rats, biliary elimination of NNK is reduced accordingly which may lead to an increased carcinogen burden in the body. In humans, inhibition of bile flow by tobacco alkaloids may contribute to the appetite suppressing effect of tobacco products.