Estudo conduzido por pesquisadores dos Departamentos de Nefrologia e Neurofisiologia Clínica do University Center Utrecht, na Holanda, investigou a atividade simpática em pacientes hipertensos e em controles, na presença e ausência de tratamentos à base de anti-hipertensivos. Após a análise dos resultados, o artigo - publicado no Journal of the American Society of Nephrology - concluiu que a atividade simpática está inapropriadamente aumentada em pacientes com doença do parênquima renal.
Journal of the American Society of Nephrology
Am Soc Nephrol 14:3239-3244, 2003
© 2003 American Society of Nephrology
Sympathetic Nerve Activity Is Inappropriately Increased in Chronic Renal Disease
Inge H.H.T. Klein*, Gerry Ligtenberg*, Jutta Neumann*, P. Liam Oey
, Hein A. Koomans* and Peter J. Blankestijn*
Departments of *Nephrology and Clinical Neurophysiology, University Medical Center Utrecht, The Netherlands
Correspondence to Dr. Peter J. Blankestijn, Department of Nephrology, Room F03.226, University Medical Center, P.O. Box 85500, 3508 GA Utrecht, The Netherlands. Phone: +31-30-2507336; Fax: +31-30-2543492; E-mail: p.j.blankestijn@azu.nl
ABSTRACT. The hypothesis that in hypertensive patients with renal parenchymal disease sympathetic activity is "inappropriately" elevated and that this overactivity is a feature of renal disease and not of a reduced number of nephrons per se is addressed. Fifty seven patients with renal disease (various causes, no diabetes, all on antihypertensive medication) were studied, age range 18 to 62, creatinine clearance 10 to 114 ml/min per 1.73 m2. Antihypertensives were stopped, but diuretics were allowed, to prevent overhydration. Matched control subjects were also studied. The effect of changes in fluid status was examined in seven patients while on and after stopping diuretics and in eight control subjects while on low- and high-sodium diet. Seven kidney donors were studied before and after unilateral nephrectomy. Sympathetic activity was quantified as muscle sympathetic nerve activity (MSNA) in the peroneal nerve. Mean arterial pressure, MSNA, and plasma renin activity were higher in patients than in control subjects, respectively (115 ± 12 and 88 ± 11 mmHg, 31 ± 15 and 18 ± 10 bursts/min, and 500 [20 to 6940] and 220 [40 to 980] fmol/L per s; P < 0.01 for all items). Extracellular fluid volume (bromide distribution) did not differ. Seven patients were studied again after stopping diuretics. MSNA decreased from 34 ± 18 to 19 ± 18 bursts/min (P < 0.01). Eight healthy subjects were studied during low- and high-sodium diet. MSNA was 26 ± 12 and 13 ± 7 bursts/min (P < 0.01). The curves relating extracellular fluid volume to MSNA were parallel in the two groups but shifted to a higher level of MSNA in the patients. In the kidney donors, creatinine clearance reduced by 25%, but MSNA was identical before and after donation. It is concluded that in hypertensive patients with renal parenchymal disease, sympathetic activity is inappropriately high for the volume status and that reduction of nephron number in itself does not influence sympathetic activity.
