3-4-dideoxyglucosone-3-ene and glucosone

Fibrosis and vascular sclerosis are main complications that limit the long-term application of peritoneal dialysis (PD). Low biocompatibility has been largely attributed to the presence of glucose degradation products (GDPs), which are formed during the heat sterilization of PD fluids. GDPs readily modify proteins in the peritoneum, leading to a decline of their biological function. After absorption, GDPs can also promote systemic protein glycation. Additionally, GDPs may augment DNA glycation, a process enhanced in uremia. Apart from their glycating activity, GDPs induce cytotoxicity and interfere with cell signaling in peritoneal mesothelial cells. Targeted screening revealed the nature of the 6 major GDPs with α-dicarbonyl structure as 3-deoxyglucosone, 3-deoxygalactosone, glucosone, glyoxal, methylglyoxal, and 3,4-dideoxyglucosone-3-ene. Valid quantification of these GDPs was achieved by ultrahigh-performance liquid chromatography/diode array detector/tandem mass spectrometry. Identification and quantification of single GDPs allow a structure-dependent risk evaluation. As a consequence, PD fluids and processes can be improved to reduce the GDP burden of patients undergoing PD.

Topics: Deoxyglucose; Dialysis Solutions; Galactose; Glucose; Glyoxal; Hot Temperature; Humans; Ketoses; Peritoneal Dialysis; Pyrones; Structure-Activity Relationship

In peritoneal dialysis (PD), glucose degradation products (GDPs), which are formed during heat sterilization of dialysis fluids, lead to structural and functional changes in the peritoneal membrane, which eventually result in the loss of its ultrafiltration capacity. To determine the molecular mechanisms behind these processes, the present study tested the influence of the six major α-dicarbonyl GDPs in PD fluids, namely, glyoxal, methylglyoxal, 3-deoxyglucosone (3-DG), 3-deoxygalactosone (3-DGal), 3,4-dideoxyglucosone-3-ene (3,4-DGE), and glucosone with respect to their potential to impair the enzymatic activity of RNase A as well as their effects on cell viability. For comprehensive risk assessment, the α-dicarbonyl GDPs were applied separately and in concentrations as present in conventional PD fluids. Thus, it was shown that after 5 days, glucosone impaired RNase A activity most distinctly (58% remaining activity, p < 0.001 compared to that of the control), followed by 3,4-DGE (62%, p < 0.001), 3-DGal (66%, p < 0.001), and 3-DG (76%, p < 0.01). Methylglyoxal and glyoxal caused weaker inactivation with significant effects only after 10 days of incubation (79%, 81%, p < 0.001). Profiling of the advanced glycation end products formed during the incubation of RNase A with methylglyoxal revealed predominant formation of the arginine modifications imidazolinone, CEA/dihydroxyimidazoline, and tetrahydropyrimidine at Arg10, Arg33, Arg39, and Arg85. Particularly, modification at Arg39 may severely affect the active site of the enzyme. Additionally, structure- and concentration-specific assessment of the cytotoxicity of the α-dicarbonyl GDPs was performed. Although present at very low concentration, the cytotoxic effect of PD fluids after 2 days of incubation was exclusively caused by 3,4-DGE (14% cell viability, p < 0.001). After 4 days of incubation, 3-DGal (13% cell viability, p < 0.001), 3-DG (24%, p < 0.001), and, to a lower extent, glyoxal and methylglyoxal (both 57%, p < 0.01) also reduced cell viability significantly. In conclusion, 3,4-DGE, 3-DGal, and glucosone appear to be the most relevant parameters for the biocompatibility of PD fluids.

Topics: Animals; Cell Proliferation; Cell Survival; Chromatography, High Pressure Liquid; Deoxyglucose; Dialysis Solutions; Galactose; Glucose; Glycation End Products, Advanced; Glyoxal; Ketoses; Mice; NIH 3T3 Cells; Peptides; Peritoneal Dialysis; Pyrones; Pyruvaldehyde; Ribonuclease, Pancreatic; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization