Unbound MEDLINE

Impaired drug-binding capacities of in vitro and in vivo glycated albumin.

Abstract

Albumin, the major circulating protein in blood, can undergo increased glycation in diabetes. One of the main properties of this plasma protein is its strong affinity to bind many therapeutic drugs, including warfarin and ketoprofen. In this study, we investigated whether or not there were any significant changes related to in vitro or in vivo glycation in the structural properties and the binding of human albumin to both therapeutic drugs. Structural parameters, including redox state and ketoamine contents of in vitro and in vivo glycated purified albumins, were investigated in parallel with their affinity for warfarin and ketoprofen. High-performance liquid chromatography was used to determine the free drug concentrations and dissociation constants according to the Scatchard method. An alternative method based on fluorescence spectroscopy was also used to assess drug-binding properties. Oxidation and glycation levels were found to be enhanced in albumin purified from diabetic patients or glycated with glucose or methylglyoxal, after determination of their ketoamine, free thiol, amino group and carbonyl contents. In parallel, significant impairments in the binding affinity of in vitro and in vivo glycated albumin, as indicated by the higher dissociation constant values and confirmed by higher free drug fractions, were observed. To a lesser extent, this alteration also significantly affected diabetic albumin affinity, indicated by a lower static quenching in fluorescence spectroscopy. This work provides useful information supporting in vivo diabetic albumin could be the best model of glycation for monitoring diabetic physiopathology and should be valuable to know if glycation of albumin could contribute to variability in drugs response during diabetes.

Links

  • Publisher Full Text

    • Authors

    Baraka-Vidot J, Guerin-Dubourg A, Bourdon E, Rondeau P

    Institution

    Groupe d'Etude sur l'Inflammation Chronique et l'Obésité, Structure fédérative Environnement Biodiversité Santé-FED4126, Université de La Réunion, Plateforme CYROI, 15, avenue René Cassin - BP 7151, 97715 Saint Denis Messag Cedex 09, La Réunion, France.

    Source

    Biochimie 94:9 2012 Sep pg 1960-7

    MeSH

    Adult
    Female
    Humans
    Ketoprofen
    Male
    Middle Aged
    Protein Binding
    Serum Albumin
    Warfarin

    Pub Type(s)

    Journal Article

    Language

    eng

    PubMed ID

    22627382