Publications

C-X-C chemokines are potent chemoattractants that are believed to mediate neutrophilic inflammation in several organs. Recent studies suggest a role for C-X-C chemokines in the pathogenesis of neutrophilic hepatitis but do not prove causation. We investigated the biological consequences of hepatic chemokine production in vivo by transiently overexpressing cytokine-induced neutrophil chemoattractant (CINC), a member of the C-X-C chemokine family, in intact rats. Rats were injected intraportally with a replication-defective recombinant adenovirus containing the CINC complementary DNA (cDNA). Within 4 days, treated animals had high levels of CINC in both liver tissue and plasma Rats overexpressing CINC exhibited an eightfold increase in circulating neutrophils; they also developed severe hepatic injury, characterized by a 6- to 25-fold increase in plasma transaminases and marked hepatic inflammation on biopsy. Liver disease in CINC-producing rats correlated positively with the number of neutrophils sequestered in the hepatic parenchyma. Tissue injury was attributed directly to chemokine overproduction, because control rats infected with adenoviruses lacking the CINC cDNA did not produce CINC and developed only minor hepatic abnormalities. These experiments provide direct evidence that C-X-C chemokines, when expressed in sufficient quantity in the liver in vivo, induce neutrophil recruitment and tissue invasion and provoke severe liver injury. The data suggest that C-X-C chemokines have important pathogenic potential in both clinical and experimental liver disease.

The association between serum beta-carotene or retinol concentration and level of ventilatory function was investigated in a population of asbestos-exposed men with a high rate of current and former cigarette smoking. The study population consisted of 816 subjects enrolled in the pilot component of the Carotene and Retinol Efficacy Trial (CARET), a placebo-controlled trial of supplemental beta-carotene and retinyl palmitate for the chemoprevention of lung cancer. Data available for analysis included baseline questionnaire, spirometry, chest X-ray, food frequency questionnaire, and serum beta-carotene and retinol concentrations. Serum beta-carotene concentration was associated with FEV1 (p < 0.05) and FVC (p < 0.05), with an approximately 100-ml increase over predicted values associated with raising the serum concentration from the 25th to the 75th percentile of the distribution in the study population (absolute difference = 155 ng/ml), even after adjustment for the confounding effects of asbestos exposure and cigarette smoking. Raising the serum retinol concentration from the 25th to the 75th percentile (absolute difference = 211 ng/ml) was associated with an approximately 70 ml increase in FVC (p < 0.05) over the predicted value. These results provide support for the hypothesis that beta-carotene and retinol have a protective effect on loss of ventilatory function.

OBJECTIVE

To examine the combined influence of workplace demands and changes in blood pressure induced by stress on the progression of carotid atherosclerosis.

DESIGN

Population based follow up study of unestablished as well as traditional risk factors for carotid atherosclerosis, ischaemic heart disease, and other outcomes.

SETTING

Eastern Finland.

SUBJECTS

591 men aged 42-60 who were fully employed at baseline and had complete data on the measures of carotid atherosclerosis, job demands, blood pressure reactivity, and covariates.

MAIN OUTCOME MEASURES

Change in ultrasonographically assessed intima-media thickness of the right and left common carotid arteries from baseline to 4 year follow up.

RESULTS

Significant interactions between workplace demands and stress induced reactivity were observed for all measures of progression (P < 0.04). Men with large changes in systolic blood pressure (20 mm Hg or greater) in anticipation of a maximal exercise test and with high job demands had 10-40% greater progression of mean (0.138 v 0.123 mm) and maximum (0.320 v 0.261 mm) intima-media thickness and plaque height (0.347 v 0.264) than men who were less reactive and had fewer job demands. Similar results were obtained after excluding men with prevalent ischaemic heart disease at baseline. Findings were strongest among men with at least 20% stenosis or non-stenotic plaque at baseline. In this subgroup reactive men with high job demands had more than 46% greater atherosclerotic progression than the others. Adjustment for atherosclerotic risk factors did not alter the results.

CONCLUSIONS

Men who showed stress induced blood pressure reactivity and who reported high job demands experienced the greatest atherosclerotic progression, showing the association between dispositional risk characteristics and contextual determinants of disease and suggesting that behaviourally evoked cardiovascular reactivity may have a role in atherogenesis.