BACKGROUND: The resemblance of the circadian rhythm of glomerular filtration rate (GFR) to that of arterial blood pressure (BP) suggests that systemic hemodynamic factors contribute to this variation. In the present study, this was investigated using continuous BP monitoring and pulse wave analysis. The study was performed in eight healthy subjects and in seven patients with nephrotic syndrome who had normal or reversed rhythms of GFR. METHODS: Circadian variations of renal function (continuous infusion of inulin/paraaminohippuric acid), noninvasive finger arterial pressure (Portapres), and vasoactive hormone levels were monitored during 27 hours. With stepwise backward regression analysis, the contributions of the measured variables to the circadian variation of GFR were investigated. RESULTS: Both groups showed a reduction of BP at night. In the controls, this was related to a drop in cardiac output, while in the patients, total peripheral resistance decreased at night. None of the hemodynamic variables explained the circadian GFR variation in both groups. In the controls, only 6% of the effective renal plasma flow (ERPF) rhythm was associated with variations in cardiac output (P = 0.03). In the patients, atrial natriuretic peptide and plasma renin activity were responsible for 36% of the variation in GFR (P < 0.01). CONCLUSIONS: These results indicate that the circadian variation of GFR does not result directly from changes in BP or cardiac output. An inverted GFR rhythm in patients with nephrotic syndrome may originate from hormonal mechanisms rather than directly from the hemodynamic effects of edema mobilization.
BACKGROUND: The resemblance of the circadian rhythm of glomerular filtration rate (GFR) to that of arterial blood pressure (BP) suggests that systemic hemodynamic factors contribute to this variation. In the present study, this was investigated using continuous BP monitoring and pulse wave analysis. The study was performed in eight healthy subjects and in seven patients with nephrotic syndrome who had normal or reversed rhythms of GFR. METHODS: Circadian variations of renal function (continuous infusion of inulin/paraaminohippuric acid), noninvasive finger arterial pressure (Portapres), and vasoactive hormone levels were monitored during 27 hours. With stepwise backward regression analysis, the contributions of the measured variables to the circadian variation of GFR were investigated. RESULTS: Both groups showed a reduction of BP at night. In the controls, this was related to a drop in cardiac output, while in the patients, total peripheral resistance decreased at night. None of the hemodynamic variables explained the circadian GFR variation in both groups. In the controls, only 6% of the effective renal plasma flow (ERPF) rhythm was associated with variations in cardiac output (P = 0.03). In the patients, atrial natriuretic peptide and plasma renin activity were responsible for 36% of the variation in GFR (P < 0.01). CONCLUSIONS: These results indicate that the circadian variation of GFR does not result directly from changes in BP or cardiac output. An inverted GFR rhythm in patients with nephrotic syndrome may originate from hormonal mechanisms rather than directly from the hemodynamic effects of edema mobilization.
Authors: Ming-Cheng Chan; Peter M Spieth; Kieran Quinn; Matteo Parotto; Haibo Zhang; Arthur S Slutsky Journal: Crit Care Med Date: 2012-01 Impact factor: 7.598
Authors: Michelle L Gumz; Kit-Yan Cheng; I Jeanette Lynch; Lisa R Stow; Megan M Greenlee; Brian D Cain; Charles S Wingo Journal: Biochim Biophys Acta Date: 2010-09-22
Authors: Sushrut S Waikar; Casey M Rebholz; Zihe Zheng; Shelley Hurwitz; Chi-Yuan Hsu; Harold I Feldman; Dawei Xie; Kathleen D Liu; Theodore E Mifflin; John H Eckfeldt; Paul L Kimmel; Ramachandran S Vasan; Joseph V Bonventre; Lesley A Inker; Josef Coresh Journal: Am J Kidney Dis Date: 2018-07-18 Impact factor: 8.860