Normal short-term renal response to acute volume expansion in heart transplant recipients: a role for atrial natriuretic peptide?
BACKGROUND
The breakdown of blood pressure and body fluid homeostasis observed in heart transplant (Htx) recipients may partly be due, as in heart failure, to a blunted renal response to elevated atrial natriuretic peptide (ANP).


METHODS
This possibility was addressed through determination of the relationship between ANP, the urinary cyclic guanosine monophosphate (cGMP), a biologic marker of ANP renal activity, and the early renal responses to 10 mL/kg isotonic saline infusion over 30 minutes in 8 control subjects and 8 matched Htx recipients.


RESULTS
Urine flow, natriuresis, and urinary cGMP excretion increased similarly in both groups, resulting in elimination of, respectively, 1/2 and 2/3 of the sodium and the water load during the experiment that lasted 4 hours and 30 minutes. Plasma renin and aldosterone decreases were similar in both groups. Elevated ANP further increased in Htx after saline infusion (from 19.5 +/- 3.7 to 33.8 +/- 5.6 pmol/L, P < .001). Plasma cGMP paralleled ANP in both groups (r = 0.81; P < .001). Significant correlations were observed between plasma ANP and urinary cGMP excretion (r = 0.48, P < .025 and r = 0.43, P < .05 in Htx recipients and control subjects) and between plasma ANP and urinary sodium excretion (r = 0.64, P < .001 in Htx recipients).


CONCLUSIONS
In spite of a relative renal hyporesponsiveness to the cardiac hormone, with higher plasma ANP being not associated with increased renal excretions in Htx recipients, ANP is likely to participate in the appropriate short-term renal response to acute volume expansion in Htx recipients.
Geny
B
B
Laboratoire d'Explorations Fonctionnelles du Système Circulatoire, Faculté de Médecine, Université Louis Pasteur, Strasbourg, France.
Charloux
A
A
Schaefer
A
A
Brandt
C
C
Charpentier
A
A
Kretz
J G
JG
Eisenmann
B
B
Haberey
P
P
Piquard
F
F
D000450:Aldosterone / Q000097:blood; D009320:Atrial Natriuretic Factor / Q000502:physiology*; D006152:Cyclic GMP / Q000502:physiology / Q000652:urine; D004231:Diuresis; D016027:Heart Transplantation / Q000502:physiology*; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009318:Natriuresis; D012083:Renin / Q000097:blood; D012964:Sodium / Q000652:urine; D012965:Sodium Chloride / Q000008:administration & dosage; D014556:Urine; D014882:Water-Electrolyte Balance / Q000502:physiology*
D012965:Sodium Chloride; D000450:Aldosterone; D009320:Atrial Natriuretic Factor; D012964:Sodium; D012083:Renin; D006152:Cyclic GMP