The renal sympathetic and renin-angiotensin response to lower body negative pressure in well-compensated cirrhosis.
OBJECTIVE
Certain antinatriuretic hormonal systems may be involved in the subclinical sodium handling abnormality in preascitic cirrhosis. The aims of this study were to determine the following in preascitic cirrhosis: (1) basal activity of the renal sympathetic and renin-angiotensin systems and (2) the relationship between the response of these systems to lower body negative pressure and sodium excretion.


METHODS
Seven preascitic cirrhotic patients and 9 age- and sex-matched controls were studied on a 150 mmol sodium per day diet. Systemic and renal hemodynamics, renal neurohormonal secretion rates, and sodium excretion were assessed before, during increasing levels of, and after lower body negative pressure, each for 30 minutes.


RESULTS
Both groups responded with a significant decrease in central venous pressure (P < 0.01) that remained higher in the cirrhotics than in the controls throughout the study. Cirrhotics showed significant increases compared with controls in renal renin and angiotensin II secretion rates at -20 mm Hg of lower body negative pressure, which was associated with significant renal sodium retention (96 +/- 17 micromol/min vs. 218 +/- 21 micromol/min at baseline, P < 0.05), but there was no change in renal sympathetic activity.


CONCLUSIONS
In preascitic cirrhosis, sodium retention occurs in response to lower body negative pressure, which was associated with increased renal renin-angiotensin activity. Stimulation of the intrarenal renin-angiotensin system may be the initial renal pathophysiological change causing sodium retention in cirrhosis.
Department of Medicine, Toronto Hospital, University of Toronto, Ontario, Canada.
F
F
Wong
K
K
Sniderman
L
L
Blendis
D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D002496:Central Venous Pressure / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007668:Kidney / Q000294:innervation*; D008104:Liver Cirrhosis, Alcoholic / Q000503:physiopathology*; D008150:Lower Body Negative Pressure; D008297:Male; D008875:Middle Aged; D009318:Natriuresis / Q000502:physiology; D012016:Reference Values; D012079:Renal Circulation / Q000502:physiology; D012084:Renin-Angiotensin System / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000503:physiopathology*