Take Care in how you Store Your PD Fluids: Actual Temperature Determines the Balance between Reactive and Non-Reactive GDPs

Abstract

Objective

During heat sterilization and during prolonged storage, glucose in peritoneal dialysis fluids (PDF) degrades to carbonyl compounds commonly known as glucose degradation products (GDPs). Of these, 3,4-dideoxyglucosone-3-ene (3,4-DGE) is the most cytotoxic. It is an intermediate in degradation between 3-deoxyglucosone (3-DG) and 5-hydroxymethyl-2-furaldehyde (5-HMF). We have earlier reported that there seems to be equilibrium between these GDPs in PDF. The aim of the present study was to investigate details of this equilibrium.

Methods

Aqueous solutions of pure 3-DG, 3,4-DGE, and 5-HMF were incubated at 40°C for 40 days. Conventional and low-GDP fluids were incubated at various temperatures for up to 3 weeks. Formaldehyde, acetaldehyde, glyoxal, methylglyoxal, 3-DG, 3,4-DGE, and 5-HMF were analyzed using high performance liquid chromatography.

Results

Incubation of 100 μmol/L 3,4-DGE resulted in the production of 36 μmol/L 3-DG, 4 μmol/L 5-HMF, and 40 μmol/L unidentified substances. With the same incubation, 200 μmol/L 3-DG was converted to 9 μmol/L 3,4-DGE, 6 μmol/L 5-HMF, and 14 μmol/L unidentified substances. By contrast, 100 μmol/L 5-HMF was uninfluenced by incubation. In a conventional PDF incubated at 60°C for 1 day, the 3,4-DGE concentration increased from 14 to a maximum of 49 μmol/L. When the fluids were returned to room temperature, the concentration decreased but did not reach original values until after 40 days. In a low GDP fluid, 3,4-DGE increased and decreased in the same manner as in the conventional fluid but reached a maximum of only 0.8 μmol/L.

Conclusions

Considerable amounts of 3,4-DGE may be recruited by increases in temperature in conventional PDFs. Lowering the temperature will again reduce the concentration but much more time will be needed. Precursors for 3,4-DGE recruitment are most probably 3-DG and the enol 3-deoxyaldose-2-ene, but not 5-HMF. Considering the ease at which 3,4-DGE is recruited from its pool of precursors and the difficulty of getting rid of it again, one should be extremely careful with the temperatures conventional PDFs are exposed to.