Chlamydia pneumoniae in carotid artery atherosclerosis: a comparison of its presence in atherosclerotic plaque, healthy vessels, and circulating leukocytes from the same individuals.
OBJECTIVE
There is growing clinical and experimental evidence that infections with Chlamydia pneumoniae might contribute to the development and progression of atherosclerosis. However, studies detecting the pathogen in atherosclerotic lesions examined either only atherosclerotic vessels or control vessels without atherosclerosis obtained from a different group of individuals. We analyzed atherosclerotic plaques of the carotid artery, samples of apparently healthy greater saphenous veins, and circulating leukocytes from the same individual patients for the presence of C pneumoniae.


METHODS
From each of 46 patients undergoing carotid endarterectomy for symptomatic carotid artery stenosis, these samples were analyzed by nested polymerase chain reaction for C pneumoniae-specific DNA. Furthermore, we determined IgA and IgG titers specific for the pathogen and plasma levels of C-reactive protein in these patients.


RESULTS
C pneumoniae DNA was detected in 86.9% of the leukocytes and in 82.6% of the atherosclerotic plaques but in only 6.5% of the saphenous veins. In 85% of patients who also had leukocytes positive for C pneumoniae, the atherosclerotic plaques were positive and the saphenous veins were negative. The presence of C pneumoniae-specific DNA in leukocytes significantly coincided with the presence of the respective DNA in the plaques of the carotid arteries (P=0.0002). No association between the presence of C pneumoniae and specific IgA or IgG levels was seen. C-reactive protein levels were significantly higher in patients with chlamydia-positive atherosclerotic plaques and with positive leukocytes than in patients with negative plaques of the carotid arteries or negative leukocytes, respectively (P<0.01, P<0.05).


CONCLUSIONS
Our observation of >80% incidence of C pneumoniae in atherosclerotic plaques of the carotid artery does not prove causality between an infection with the pathogen and the development of atherosclerosis. It must be emphasized, however, that >90% of apparently healthy saphenous veins were negative for C pneumoniae. Given the structural and functional differences between veins and arteries, careful interpretation of our results regarding a possible causative role of C pneumoniae seems warranted.
Prager
Manfred
M
Department of Vascular Surgery, University of Vienna, Vienna, Austria.
Türel
Zeynep
Z
Speidl
Walter S
WS
Zorn
Gerlinde
G
Kaun
Christoph
C
Niessner
Alexander
A
Heinze
Georg
G
Huk
Igor
I
Maurer
Gerald
G
Huber
Kurt
K
Wojta
Johann
J
D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D002339:Carotid Arteries / Q000382:microbiology* / Q000473:pathology / Q000601:surgery; D002340:Carotid Artery Diseases / Q000382:microbiology* / Q000473:pathology / Q000601:surgery; D016993:Chlamydophila pneumoniae / Q000235:genetics / Q000302:isolation & purification*; D004269:DNA, Bacterial / Q000032:analysis; D016894:Endarterectomy, Carotid; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007962:Leukocytes / Q000737:chemistry / Q000382:microbiology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012501:Saphenous Vein / Q000737:chemistry / Q000382:microbiology* / Q000473:pathology; D012698:Serologic Tests
D000907:Antibodies, Bacterial; D004269:DNA, Bacterial; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D002097:C-Reactive Protein