Association between interleukin-6 and carotid atherosclerosis in hemodialysis patients.
BACKGROUND
Interleukin-6 (IL-6) is associated with cardiovascular complications in general subjects. Although blood IL-6 is greatly elevated in hemodialysis (HD) patients, the role of IL-6 in the advance of atherosclerosis remains to be determined.


METHODS
We conducted a cross-sectional study to investigate the relationship between circulating IL-6 and carotid atherosclerotic changes in 156 HD patients (age 58 +/- 1 years; time on HD treatment 13 +/- 1 years; 97 males and 59 females). Serum IL-6, IgG and IgA titers of Chlamydia pneumoniae antibodies, the intima-media thickness (IMT) and the cross-sectional intima-media area (IMarea) of the carotid arteries were measured by ultrasonography in each patient.


RESULTS
Serum IL-6 levels were significantly higher in HD patients (2.04 +/- 0.16 pg/mL) compared to normal age-matched control subjects (0.31 +/- 0.06 pg/mL, N = 24). Circulating log IL-6 levels were positively correlated with IMT (r = 0.278, P < 0.01) and IMarea (r = 0.344, P < 0.01), respectively. A stepwise multiple regression analysis revealed that IL-6 became significant predictors for IMT and IMarea but not for aortic wall calcification at L2/3 vertebrae. Serum log IL-6 was significantly correlated with IgG (r = 0.277, P < 0.01) and IgA titers of anti-Chlamydia antibodies (r = 0.192, P < 0.02). Serum IgA anti-Chlamydia titers were also correlated with the maximal diameter of carotid plaque (r = 0.293, P < 0.04).


CONCLUSIONS
These findings suggested that IL-6 is associated with the severity of carotid atherosclerosis in HD patients. Persistent chronic chlamydial infection may be related, in part, to the advance of carotid plaque enlargement in dialysis patients.
Kato
Akihiko
A
First Department of Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu, 431-3192 Japan. akato@hama-med.ac.jp
Odamaki
Mari
M
Takita
Takako
T
Maruyama
Yukitaka
Y
Kumagai
Hiromichi
H
Hishida
Akira
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D002340:Carotid Artery Diseases / Q000097:blood* / Q000000981:diagnostic imaging / Q000503:physiopathology; D016993:Chlamydophila pneumoniae / Q000276:immunology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D006435:Renal Dialysis; D012720:Severity of Illness Index; D014463:Ultrasonography
D000907:Antibodies, Bacterial; D007070:Immunoglobulin A; D015850:Interleukin-6