4-Pyridoxic Acid in the Spent Dialysate: Contribution to Fluorescence and Optical Monitoring

PLoS One. 2016 Sep 6;11(9):e0162346. doi: 10.1371/journal.pone.0162346. eCollection 2016.

Abstract

Aim: In this work we estimated the contribution of the fluorescence of 4-pyridoxic acid (4-PA) to the total fluorescence of spent dialysate with the aim of evaluating the on-line monitoring of removal of this vitamin B-6 metabolite from the blood of patients with end-stage renal disease (ESRD).

Methods: Spectrofluorometric analysis of spent dialysate, collected from hemodialysis and hemodiafiltration sessions of 10 patients receiving regularly pyridoxine injections after dialysis treatment, was performed in the range of Ex/Em 220-500 nm. 4-PA in dialysate samples was identified and quantified using HPLC with fluorescent and MS/MS detection.

Results: Averaged HPLC chromatogram of spent dialysate had many peaks in the wavelength region of Ex320/Em430 nm where 4-PA was the highest peak with contribution of 42.2±17.0% at the beginning and 47.7±18.0% in the end of the dialysis. High correlation (R = 0.88-0.95) between 4-PA concentration and fluorescence intensity of spent dialysate was found in the region of Ex310-330/Em415-500 nm, respectively.

Conclusion: 4-PA elimination from the blood of ESRD patients can be potentially followed using monitoring of the fluorescence of the spent dialysate during dialysis treatments.

MeSH terms

  • Aged
  • Biotransformation
  • Chromatography, High Pressure Liquid
  • Dialysis Solutions
  • Female
  • Fluorescence
  • Hemodiafiltration*
  • Humans
  • Kidney Failure, Chronic / blood*
  • Kidney Failure, Chronic / complications
  • Kidney Failure, Chronic / diagnosis
  • Kidney Failure, Chronic / therapy
  • Male
  • Middle Aged
  • Pyridoxic Acid / blood*
  • Spectrometry, Fluorescence
  • Vitamin B 6 / administration & dosage
  • Vitamin B 6 / blood*
  • Vitamin B 6 / pharmacokinetics
  • Vitamin B 6 Deficiency / blood*
  • Vitamin B 6 Deficiency / complications
  • Vitamin B 6 Deficiency / diagnosis
  • Vitamin B 6 Deficiency / therapy

Substances

  • Dialysis Solutions
  • Pyridoxic Acid
  • Vitamin B 6

Grants and funding

We would like to thank all the participating patients. The study was supported by the European Union through the European Regional Development Fund and the Estonian Ministry of Education and Research (https://www.hm.ee/en) under institutional research funding IUT19-02. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.