Is the pregnancy hormone relaxin an important player in human heart failure?
BACKGROUND
The pregnancy hormone relaxin has been raised as a new compensatory mediator of cardiac origin in heart failure (HF). We set out to assess the role of relaxin in pressure overload-induced human HF.


METHODS
We studied 129 adult patients undergoing cardiac catheterization for isolated aortic valve stenosis (AS). Blood was sampled from the aortic root and, in a subset of 49 patients, from the coronary sinus for the determination of plasma relaxin by enzyme immunoassay. HF was diagnosed when the patient had dyspnea or fatigue on ordinary effort in association with pulmonary wedge pressure >14 mm Hg at catheterization.


RESULTS
Forty-one patients had HF, which was systolic (ejection fraction <50%) in 16 patients and diastolic in 25 patients. The median plasma relaxin was 32 pg/ml (<12-297 pg/ml) in 88 AS patients without HF, 28 pg/ml (<12-825 pg/ml) in the 41 AS patients with HF, and 42 pg/ml (range, <12-100 pg/ml) in 11 control patients free of heart disease (p=0.82). Plasma relaxin did not correlate with any measurement of cardiac structure or function. The concentration gradients of relaxin from the aortic root to the coronary sinus indicated relaxin extraction by the heart in the control patients (median change, -5 pg/ml, p=0.038) vs. relaxin production in patients with systolic HF (median change, +6 pg/ml, p=0.028) (p=0.002 between groups).


CONCLUSIONS
Although the heart may release relaxin into the circulation in certain forms of HF, this does not translate into elevated systemic concentrations. Relaxin is not a major player in human HF.
Kupari
Markku
M
Division of Cardiology, Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland. markku.kupari@hus.fi
Mikkola
Tomi S
TS
Turto
Heikki
H
Lommi
Jyri
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000097:blood* / Q000150:complications; D006328:Cardiac Catheterization; D002303:Cardiac Output, Low / Q000097:blood* / Q000209:etiology; D016022:Case-Control Studies; D019332:Endothelin-1 / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain; D009419:Nerve Tissue Proteins / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D012065:Relaxin / Q000097:blood*
D019332:Endothelin-1; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain; D012065:Relaxin