Intracellular Phosphate Dynamics in Muscle Measured by Magnetic Resonance Spectroscopy during Hemodialysis

• Published in: Journal of the American Society of Nephrology 2016-07, Vol.27 (7), p.2062-2068
• Main Authors: Lemoine, Sandrine, Fournier, Thomas, Kocevar, Gabriel, Belloi, Amélie, Normand, Gabrielle, Ibarrola, Danielle, Sappey-Marinier, Dominique, Juillard, Laurent
• Format: Article
• Language: English
• Subjects: Animals; Basic Research; Female; Intracellular Space - metabolism; Life Sciences; Magnetic Resonance Spectroscopy; Muscle, Skeletal - metabolism; Phosphates - metabolism; Renal Dialysis; Swine
• ISSN: 1046-6673; 1533-3450
• DOI: 10.1681/ASN.2015050546

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