Induction of interleukin-18 in atherosclerotic patients: a role for Chlamydia pneumoniae.
OBJECTIVE
The present work explored gene expression and spontaneous induction of the inflammatory cytokine interleukin-18 (IL-18) in atherosclerotic patients. In addition, the effect of the chlamydial antigen heat shock protein 60 (HSP60) and lipopolysaccharide (LPS) on the induction of this mediator was examined.


METHODS
Detection of IL-18 mRNA and protein level were assessed by in situ hybridization and immunohistochemistry, respectively, in 15 patients with coronary artery disease undergoing angiograms and 15 matching controls.


RESULTS
These experiments showed significantly high levels of spontaneously expressed IL-18 mRNA and high protein levels in patients compared to healthy controls (p < 0.0005). Cells stimulated with chlamydial HSP60 (CHSP60) and LPS showed a significantly high expression of IL-18 at the mRNA level (p < 0.0005 for CHSP60 and p < 0.005 for LPS) and an increased production of IL-18 at protein level (p < 0.0005 for CHSP60 and p < 0.005 for LPS).


CONCLUSIONS
This study demonstrated de novo synthesis of the inflammatory cytokine IL-18 in atherosclerosis and, furthermore, that chlamydial antigens might play a role in the immunopathological events in this disease by generating more inflammatory mediators such as IL-18.
Mousa
Alyaa
A
Department of Anatomy, Faculty of Medicine, Health Sciences Centre, Kuwait University, Safat, Kuwait. amousa@hsc.edu.kw
Al-Zaki
Amani
A
Taha
Safa
S
Bakhiet
Moiz
M
D050197:Atherosclerosis / Q000150:complications / Q000503:physiopathology*; D002318:Cardiovascular Diseases / Q000150:complications; D018834:Chaperonin 60 / Q000494:pharmacology*; D016993:Chlamydophila pneumoniae; D048909:Diabetes Complications; D005260:Female; D015870:Gene Expression; D006801:Humans; D020382:Interleukin-18 / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger
D018834:Chaperonin 60; D020382:Interleukin-18; D008070:Lipopolysaccharides; D012333:RNA, Messenger