Effect of acetate, bicarbonate dialysis, and acetate-free biofiltration on nitric oxide synthesis: Implications for dialysis hypotension

Marina Noris, Marta Todeschini, Federica Casiraghi, Dario Roccatello, Guido Martina, Luigi Minetti, Barbara Imberti, Flavio Gaspari, Mauro Atti, Giuseppe Remuzzi

Research output: Contribution to journalArticlepeer-review

Abstract

The effect of acetate dialysis (AD), bicarbonate dialysis (BD), and acetate-free biofiltration (AFB) on nitric oxide (NO) synthesis and the implications for dialysis hypotension was studied. The finding that uremic plasma is a potent inducer of NO synthesis by endothelial cells in vitro suggested that the cardiovascular instability of dialysis patients might result from excessive NO formation. Cardiovascular instability is more frequent in patients undergoing AD than BD. To see whether these differences were attributable to NO, we studied the NO synthetic pathway ex vivo in patients undergoing different dialysis procedures. Five patients were treated, in a random order, with AD, BD, and AFB, a technique using a buffer- free dialysate and postdilution of a sterile bicarbonate solution. Each type of dialysis was used for 1 week, comprising three dialysis sessions. A polyacrylonitrile dialyzer was used for all three methods. Before and after the third dialysis, plasma was collected, added to [3H]L-arginine, and incubated with human umbilical vein endothelial cells (HUVECs) for 24 hours. NO synthesis was evaluated as [3H]L-citrulline formation. Plasma concentrations of interleukin-1β (IL-1β), a potent inducer of inducible NO synthase (INOS) in endothelial cells, were also measured. Plasma collected from patients after AD stimulated endothelial NO synthesis more than plasma from the same patients before the dialysis session (pre-AD, 0.173 ± 0.028 nmol/105 cells v post-AD, 0.280 ± 0.093 nmol/105 cells; P <0.05). A slight, although not significant, increase was also observed when HUVECs were incubated with plasma drawn after BD (pre-BD, 0.151 ± 0.014 nmol/105 cells; post-BD, 0.230 ± 0.055 nmol/105 cells). AFB did not aggravate the stimulatory effect of uremic plasma on endothelial NO synthesis (pre-AFB, 0.184 ± 0.038 nmol/105 cells; post-AFB, 0.189 ± 0.040 nmol/105 cells). Plasma IL-1β was greater (P <0.01) after AD than after BD and AFB (post- AD, 0.234 ± 0.028 pg/mL; post-BD, 0.124 ± 0.019 pg/mL; post-AFB, 0.120 ± 0.013 pg/mL). With AD, there was a greater intradialytic decrease in systolic blood pressure than with BD or AFB. Weight and blood volume loss and sodium balance were similar in AD, BD, and AFB. These data were consistent with the possibility that NO and cytokines, released in excessive amounts during AD, may contribute to hemodynamic instability.

Original languageEnglish
Pages (from-to)115-124
Number of pages10
JournalAmerican Journal of Kidney Diseases
Volume32
Issue number1
Publication statusPublished - Jul 1998

Keywords

  • Acetate dialysate
  • Acetatefree biofiltration
  • Bicarbonate dialysate
  • Dialysis
  • Endothelial cells
  • Hypotension
  • Interleukin-1
  • Monocytes
  • Nitric oxide
  • Patients

ASJC Scopus subject areas

  • Nephrology

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