Angiotensin type 2 receptor is expressed in human atherosclerotic lesions.
OBJECTIVE
Expression of the angiotensin type 2 receptor (AT2-receptor) occurs in many animal models of atherosclerosis. However, its expression in human plaques and its functional role remains undetermined. This study examined AT2-receptor expression in human atherosclerotic plaque and also explored its potentially important functional role in atherosclerosis.


METHODS
We analysed carotid atherosclerotic plaques obtained from 14 Caucasian patients who had previously undergone endarterectomy for symptomatic carotid artery stenosis. Half of all subjects received treatment with an angiotensin receptor blocker (ARB) (n=7); the remaining subjects received no intervention in the renin-angiotensin system (n=7). Immunohistochemistry measured tissue expression of smooth muscle cells (a-actin), macrophages (CD68 antibody), collagen (picro-sirius), and AT2-receptor (AT2-receptor antibody).


RESULTS
AT2-receptor expression occurred consistently in all specimens. Although cellular localisation varied, AT2-receptor expression levels correlated with macrophage levels (p<0.01). Compared to conventional treatment, ongoing ARB treatment affected neither AT2-receptor levels nor plaque composition.


CONCLUSIONS
AT2-receptor is expressed in human atherosclerotic plaque. Furthermore, we detected no functionally important role of AT2-receptor expression and found no evidence that ARB treatment regulates AT2-receptor expression.
Johansson
Maria E
ME
Department of Molecular and Clinical Medicine/Clinical Physiology, The Sahlgrenska Academy, Göteborg University, Göteborg, Sweden.
Fagerberg
Björn
B
Bergström
Göran
G
D000368:Aged; D057912:Angiotensin II Type 2 Receptor Blockers; D015703:Antigens, CD / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D050197:Atherosclerosis / Q000378:metabolism* / Q000473:pathology; D016893:Carotid Stenosis / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D044139:Receptor, Angiotensin, Type 2 / Q000096:biosynthesis*; D000097382:CD68 Molecule
D057912:Angiotensin II Type 2 Receptor Blockers; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D044139:Receptor, Angiotensin, Type 2; C067980:CD68 antigen, human; D000097382:CD68 Molecule