Urotensin II receptor expression in human right atrium and aorta: effects of ischaemic heart disease.
BACKGROUND
Urotensin II (UII) and its receptor UT are involved in control of the cardiovascular system and are implicated in heart failure. We measured UT expression by quantitative PCR (Q-PCR) in atrial and aortic tissue, and plasma UII while simultaneously assessing cardiac function in 40 patients undergoing coronary artery bypass surgery.


METHODS
RNA extracted from atrial and aortic samples was probed with specific Q-PCR UT and housekeeper (glyceraldehyde-3-phosphate dehydrogenase, GAPDH) TaqMan primers. Plasma UII was measured using radioimmunoassay. Left ventricular ejection fraction (LVEF) was measured using preoperative trans-thoracic echocardiography and ventriculography, and intraoperatively using transoesophageal echocardiography. Q-PCR data are expressed as difference in cycle threshold (DeltaC(t)=C(tUT)-C(tGAPDH): high number indicates low expression).


RESULTS
There was no difference in DeltaC(t) in either atrium or aorta between patients with normal (LVEF >50%) or those with impaired (LVEF <50%) preoperative systolic function. There was a weak negative correlation (r(2)=0.245, P=0.031) between intraoperative LVEF and DeltaC(t) in 19 patients possibly indicating down-regulation of UT with worsening LVEF. Atria expressed significantly more UT than aorta (P=0.011). In the absence of non-diseased controls, plasma UII was higher than a historical control group.


CONCLUSIONS
This is the first study to simultaneously measure UT (mRNA), UII, and cardiovascular function. Collectively, these pilot data may suggest a down-regulation of UT within the right atrium of patients with heart failure.
Leonard
A D
AD
Department of Cardiovascular Sciences (Pharmacology and Therapeutics Group), Division of Anaesthesia, Critical Care and Pain Management, University of Leicester, Leicester Royal Infirmary, Leicester LE1 5WW, UK.
Thompson
J P
JP
Hutchinson
E L
EL
Young
S P
SP
McDonald
J
J
Swanevelder
J
J
Lambert
D G
DG
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001013:Aorta, Thoracic / Q000378:metabolism; D015415:Biomarkers / Q000097:blood; D002478:Cells, Cultured; D001026:Coronary Artery Bypass; D005260:Female; D015870:Gene Expression; D006325:Heart Atria / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000378:metabolism* / Q000503:physiopathology; D009206:Myocardium / Q000378:metabolism*; D010865:Pilot Projects; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000032:analysis; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D013318:Stroke Volume; D014579:Urotensins / Q000097:blood; D016277:Ventricular Function, Left
D015415:Biomarkers; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; C121697:UTS2R protein, human; D014579:Urotensins; C029677:urotensin II