Intracellular Phosphate Concentration Evolution During Hemodialysis by MR Spectroscopy
Condition: End-Stage Renal Disease (ESRD)
MeSH terms: Kidney Failure, Chronic
Study type: Interventional

Summary: 
      End-stage renal disease is associated with hyperphosphatemia due to a decrease of renal
      phosphate excretion. This hyperphosphatemia is associated with an increase of cardiovascular
      risk and mortality. Thus, three therapeutic options have been developed: dietary restriction,
      administration of phosphate binders and phosphorus clearance by hemodialysis (HD).

      During a standard HD session, around 600 to 700mg phosphate is removed from the plasma,
      whereas it contains only 90 mg inorganic phosphate (Pi); 85% of phosphate is stored in bones
      and teeth in hydroxyapatite form, 14% is stored in the intracellular space (90% organic
      phosphate and 10% Pi), and 1% remains in the extracellular space.

      Currently, the source of Pi cleared during HD remains to be determined. Phosphorus (31P)
      magnetic resonance spectroscopy allows reliable, dynamic and non-invasive measurements of
      phosphate intracellular concentration. The investigator's team recently published data
      obtained in anephric pigs, suggesting that phosphate intracellular concentration increases
      during a HD session. In parallel, we showed that ATP intracellular concentration decreased.
      These results suggest that the source of Pi cleared during HD could be located inside the
      cell.

      In this study, investigators will measure intracellular phosphate and ATP concentrations and
      intracellular potential of hydrogen (pH) evolution during hemodialysis in 12 patients
      suffering from end-stage renal disease by MR spectroscopy.

      If these results were confirmed in humans, it could explain, at least in part, HD intolerance
      in some patients and would lead to modify therapeutic approaches of hyperphosphatemia, for
      example, by modifying HD sessions time.
    


Intervention name(s): Phosphorus (31P) magnetic resonance spectroscopy; Hemodialysis
Intervention type(s): Device; Other
Intervention description(s): Phosphorus MR spectroscopy realized using a 3-Tesla MR imaging system. A twenty-cm circular surface coil will be set to the 31P resonance frequency and placed over the leg muscle region to obtain spectroscopy acquisitions. 31P MR spectra will be acquired before, during (every 160 seconds), and 30 minutes after dialysis. 31P MR system data will be analyzed using jMRUI Software. Five different peaks will be analyzed: inorganic phosphate, phosphocreatine, α-, β-, and γ-ATP.; Hemodialysis realized using a 5008 generator, a portable plant, a FX80 Dialyzer, a dialyzing solution with a standard electrolytes composition. The dialysis generator will be placed outside of the MRI examination room. The dialysis lines will pass through a wave guide to connect patients positioned on the bed of the MRI. A suitably trained nurse will proceed to the cannulation of the fistula, the connection of the catheter, and the monitoring of the clinical tolerance of the session.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: ESRD; hemodialysis; phosphate; ATP; magnetic resonance spectroscopy