title: Modifications to bicarbonate conductivity: A way to increase phosphate removal during hemodialysis? Proof of concept.
abstract: Introduction Hyperphosphatemia and cardiovascular mortality are associated particularly with end-stage renal disease. Available therapeutic strategies (i.e., diet restriction, calcium [or not]-based phosphate binders, calcimimetics) are associated with extrarenal blood purification. Compartmentalization of phosphate limits its depuration during hemodialysis. Several studies suggest that plasmatic pH is involved in the mobilization of phosphate from intracellular to extracellular compartments. Consequently, the efficiency of modified bicarbonate conductivity to purify blood phosphate was tested. Methods Ten hemodialysis patients with chronic hyperphosphatemia (>2.1 mmol/L) were included in the two three-sessions-per week periods. Bicarbonate concentration was fixed at 40 mmol/L and 30 mmol/L in the first and second periods, respectively. Phosphate depuration was evaluated by phosphate mobilization clearance (KM). Findings Although bicarbonatemia was lower during the second period (21.0 ± 2.7 vs. 24.4 ± 3.1 mmol/L, P < 0.01), no difference was observed in phosphatemia (2.4 ± 0.5 vs. 2.3 ± 0.4 mmol/L, P = NS). The in-session variation of phosphate was lower (-1.45 ± 0.42 vs. -1.58 ± 0.44 mmol/L, P < 0.05) and KMwas higher during the second period (82.94 ± 38.00 vs. 69.74 ± 24.48 mL/min, P < 0.05). Discussion The decrease of in-session phosphate and the increase in KMreflect phosphate refilling during hemodialysis. Thus, modulation of serum bicarbonate may play a role in controlling the phosphate pool. Even though correcting metabolic acidosis during hemodialysis remains important, alkaline excess can impair phosphate mobilization clearance. Clinical trials are needed to test the efficiency and relevance of a strategy where bicarbonatemia is corrected less at the beginning of sessions.
authors.affiliation: Nephrology, Hemodialysis and Transplantation Unit, Reims University Hospital, Reims, France. jean-philippe.bertocchio@aphp.fr.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Bertocchio
authors.affiliation: Nephrology, Hemodialysis and Transplantation Unit, Reims University Hospital, Reims, France.
authors.forename: Médérick
authors.initials: M
authors.lastname: Mohajer
authors.affiliation: Nephrology, Hemodialysis and Transplantation Unit, Reims University Hospital, Reims, France.
authors.forename: Khaled
authors.initials: K
authors.lastname: Gaha
authors.affiliation: CHU de Reims, Laboratoire Central de Biochimie, 51092, Reims, France.|Université de Reims Champagne-Ardenne, CNRS UMR 7369 (Matrice Extracellulaire et Dynamique Cellulaire, MEDyC), 51095, Reims, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Ramont
authors.affiliation: Nephrology, Hemodialysis and Transplantation Unit, Reims University Hospital, Reims, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Maheut
authors.affiliation: Nephrology, Hemodialysis and Transplantation Unit, Reims University Hospital, Reims, France.|Université de Reims Champagne-Ardenne, CNRS UMR 7369 (Matrice Extracellulaire et Dynamique Cellulaire, MEDyC), 51095, Reims, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Rieu
mesh_terms: D000368:Aged; D001639:Bicarbonates / Q000737:chemistry*; D005260:Female; D006801:Humans; D054559:Hyperphosphatemia / Q000628:therapy*; D007676:Kidney Failure, Chronic / Q000628:therapy*; D008297:Male; D010710:Phosphates / Q000097:blood*; D006435:Renal Dialysis / Q000379:methods*
chemical_list: D001639:Bicarbonates; D010710:Phosphates
keywords: Renal dialysis; acid-base equilibrium; phosphorus; phosphorus metabolism disorders