A novel method to quantify in vivo transferrin glycation: applications in diabetes mellitus.
BACKGROUND
In vitro glycation of transferrin leads to increased oxidative stress by impairing iron-binding antioxidant capacity. The aim of this study is to develop a method to evaluate in vivo transferrin glycation in diabetes.


METHODS
We adapted the nitroblue tetrazolium assay to measure in micro-well plates the fructosamine content of transferrin isolated from serum by immunocomplexation.


RESULTS
Introduction of the immunocomplexation step did not affect the analytical performance of the fructosamine measurement and analytical variability was lower than 7%. The diabetic group (n=107) had significantly higher transferrin glycation (1.39+/-1.12 versus 0.79+/-1.09 micromol fructosamine/g transferrin in the non-diabetic group, n=91, p<0.0005) and this was most pronounced in type 1 diabetes (1.95+/-1.02 versus 1.06+/-1.04 micromol fructosamine/g transferrin in type 2, p<0.0005). Transferrin glycation was associated with parameters of glycaemic control but did not correlate with serum iron or total iron-binding capacity. Total iron-binding capacity was lower in type 1 diabetes (63+/-9 versus 69+/-12 micromol/l in type 2, p<0.05) and was mainly determined by transferrin concentration.


CONCLUSIONS
These results indicate that the adapted nitroblue tetrazolium assay combined with immunocomplexation of serum transferrin is suitable to detect differences in in vivo transferrin glycation between non-diabetic, type 1 and type 2 diabetic subjects.
Van Campenhout
Ann
A
Laboratory of Endocrinology, Antwerp Metabolic Research Unit, University of Antwerp, T 4.37, Universiteitsplein 1, B-2610 Wilrijk-Antwerp, Belgium. ann.vancampenhout@ua.ac.be
Van Campenhout
Christel
C
Olyslager
Yung S
YS
Van Damme
Oliver
O
Lagrou
Albert R
AR
Manuel-y-Keenoy
Begoña
B
D003920:Diabetes Mellitus / Q000097:blood* / Q000378:metabolism; D005260:Female; D006031:Glycosylation; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007501:Iron / Q000097:blood; D008297:Male; D008875:Middle Aged; D014168:Transferrin / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism*
D014168:Transferrin; D007501:Iron