title: Intracellular Phosphate Dynamics in Muscle Measured by Magnetic Resonance Spectroscopy during Hemodialysis.
abstract: Of the 600-700 mg inorganic phosphate (Pi) removed during a 4-hour hemodialysis session, a maximum of 10% may be extracted from the extracellular space. The origin of the other 90% of removed phosphate is unknown. This study tested the hypothesis that the main source of phosphate removed during hemodialysis is the intracellular compartment. Six binephrectomized pigs each underwent one 3-hour hemodialysis session, during which the extracorporeal circulation blood flow was maintained between 100 and 150 ml/min. To determine in vivo phosphate metabolism, we performed phosphorous ((31)P) magnetic resonance spectroscopy using a 1.5-Tesla system and a surface coil placed over the gluteal muscle region. (31)P magnetic resonance spectra (repetition time =10 s; echo time =0.35 ms) were acquired every 160 seconds before, during, and after dialysis. During the dialysis sessions, plasma phosphate concentrations decreased rapidly (-30.4 %; P=0.003) and then, plateaued before increasing approximately 30 minutes before the end of the sessions; 16 mmol phosphate was removed in each session. When extracellular phosphate levels plateaued, intracellular Pi content increased significantly (11%; P<0.001). Moreover, βATP decreased significantly (P<0.001); however, calcium levels remained balanced. Results of this study show that intracellular Pi is the source of Pi removed during dialysis. The intracellular Pi increase may reflect cellular stress induced by hemodialysis and/or strong intracellular phosphate regulation.
authors.affiliation: Service d'exploration Fonctionnelle Rénale and Service de Néphrologie, Hôpital E. Herriot, Hospices Civils de Lyon, Lyon, France; Cardiovasculaire, Métabolisme, Diabétologie et Nutrition (CarMeN U1060 Institut National de la Santé et de la Recherche Médicale), University of Lyon, University Claude Bernard Lyon 1, Lyon, France; and sandrine.lemoine01@chu-lyon.fr.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Lemoine
authors.affiliation: Service de Néphrologie, Hôpital E. Herriot, Hospices Civils de Lyon, Lyon, France;
authors.forename: Thomas
authors.initials: T
authors.lastname: Fournier
authors.affiliation: University of Lyon, University Claude Bernard Lyon 1, Lyon, France; and Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (Unité Mixte de Recherche 5220 Centre national de la recherche scientifique and U1044 Institut National de la Santé et de la Recherche Médicale ), and.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Kocevar
authors.affiliation: Service de Néphrologie, Hôpital E. Herriot, Hospices Civils de Lyon, Lyon, France;
authors.forename: Amélie
authors.initials: A
authors.lastname: Belloi
authors.affiliation: Service de Néphrologie, Hôpital E. Herriot, Hospices Civils de Lyon, Lyon, France; University of Lyon, University Claude Bernard Lyon 1, Lyon, France; and.
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Normand
authors.affiliation: Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (Unité Mixte de Recherche 5220 Centre national de la recherche scientifique and U1044 Institut National de la Santé et de la Recherche Médicale ), and.
authors.forename: Danielle
authors.initials: D
authors.lastname: Ibarrola
authors.affiliation: University of Lyon, University Claude Bernard Lyon 1, Lyon, France; and Centre de Recherche en Acquisition et Traitement de l'Image pour la Santé (Unité Mixte de Recherche 5220 Centre national de la recherche scientifique and U1044 Institut National de la Santé et de la Recherche Médicale ), and Centre d'Etude et de Recherche Multimodale Et Pluridisciplinaire en imagerie du vivant, Imagerie du Vivant, Bron, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Sappey-Marinier
authors.affiliation: Service de Néphrologie, Hôpital E. Herriot, Hospices Civils de Lyon, Lyon, France; Cardiovasculaire, Métabolisme, Diabétologie et Nutrition (CarMeN U1060 Institut National de la Santé et de la Recherche Médicale), University of Lyon, University Claude Bernard Lyon 1, Lyon, France; and.
authors.forename: Laurent
authors.initials: L
authors.lastname: Juillard
mesh_terms: D000818:Animals; D005260:Female; D042541:Intracellular Space / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D018482:Muscle, Skeletal / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*; D006435:Renal Dialysis; D013552:Swine
chemical_list: D010710:Phosphates
keywords: chronic dialysis; hyperphosphatemia; intracellular pH; intracellular signal; ion transport; phosphate uptake