Monocyte angiotensin converting enzyme expression may be associated with atherosclerosis rather than arteriosclerosis in hemodialysis patients.
OBJECTIVE
Circulating monocytes can be divided into functionally distinct subpopulations according to their surface expression of CD14 and CD16. Monocytes with high-level expression of both antigens (CD14(++)CD16(+), Mo2 cells) are associated with cardiovascular morbidity and mortality in hemodialysis patients. These cells express angiotensin converting enzyme (ACE) on their surface. They are involved in the association of chronic inflammation and cardiovascular disease in kidney patients. Cardiovascular morbidity results from atherosclerosis (plaque-forming, vessel occluding disease) and arteriosclerosis (loss of arterial dampening function). It is unknown whether ACE-expressing proinflammatory monocytes are related to atherosclerosis, arteriosclerosis, or both.


METHODS
During baseline examination for a prospective study on monocyte ACE expression and mortality, 60 chronic hemodialysis patients of an academic outpatient center were screened for atherosclerosis by carotid artery ultrasound, for arteriosclerosis by pulse pressure measurement, and for ACE expression on Mo2 cells by flow cytometry.


RESULTS
ACE expression on Mo2 monocytes was significantly higher in patients with severe compared with those with little or no carotid atherosclerosis. Mo2 ACE correlated with a score to semiquantify atherosclerosis and remained a significant predictor of carotid plaques in multivariate analysis including the other univariately associated variables of age, hemoglobin A1c, and albumin. Mo2 ACE was not related to pulse pressure.


CONCLUSIONS
ACE expression on Mo2, although being a known predictor of mortality and cardiovascular disease in end-stage renal disease patients, may act via enhancement of atherosclerosis rather than arteriosclerosis.
Department of Internal Medicine II, Martin Luther University, Halle-Wittenberg, Germany.
Christof
C
Ulrich
Eric
E
Seibert
Gunnar H
GH
Heine
Danilo
D
Fliser
Matthias
M
Girndt
D000046:Academic Medical Centers; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001161:Arteriosclerosis / Q000175:diagnosis / Q000201:enzymology / Q000209:etiology* / Q000503:physiopathology; D050197:Atherosclerosis / Q000000981:diagnostic imaging / Q000201:enzymology / Q000209:etiology*; D001794:Blood Pressure; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging / Q000201:enzymology* / Q000209:etiology / Q000503:physiopathology; D005260:Female; D005434:Flow Cytometry; D058851:GPI-Linked Proteins / Q000097:blood; D005858:Germany; D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications / Q000628:therapy*; D016014:Linear Models; D018950:Lipopolysaccharide Receptors / Q000097:blood; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000201:enzymology* / Q000276:immunology; D007703:Peptidyl-Dipeptidase A / Q000097:blood*; D011446:Prospective Studies; D011673:Pulsatile Flow; D017452:Receptors, IgG / Q000097:blood; D006435:Renal Dialysis / Q000009:adverse effects; D014463:Ultrasonography
C428200:FCGR3B protein, human; D058851:GPI-Linked Proteins; D018950:Lipopolysaccharide Receptors; D017452:Receptors, IgG; D007703:Peptidyl-Dipeptidase A