Structural and glycation site changes of albumin in diabetic patient with very high glycated albumin.
BACKGROUND
Glycated albumin (GA) has been utilized to monitor mid-term glycemic control, and reflects the status of blood glucose more rapidly and effectively than hemoglobin A(1c) (HbA(1c)). To examine the relationship between GA level and structural changes or glycation sites of albumin, we analyzed pre- and post-treatment samples from a diabetic patient with extraordinary increase of GA.


METHODS
A female diabetic patient with poor glycemic control had a GA >94% and was treated with intensive insulin therapy to decrease blood glucose. We analyzed changes in fluorescence derived from tryptophan (Trp) and advanced glycation end product (AGE) of albumin isolated/purified from pre- and post-treatment samples. To determine the sites of glycation of albumin, samples were carboxymethylated and digested by Glu-C endoprotease, and peptides were analyzed using liquid chromatography/mass spectrometry.


RESULTS
GA level decreased almost linearly and reflected the improved glycemic state well. Trp-related fluorescence of pre- and post-treated samples did not change while AGE-related fluorescence increased depending on GA level. Ten major glycation sites were detected in the pre-treatment sample, while 3 major glycation sites were detected in post-treated samples.


CONCLUSIONS
GA level reflects the status of blood glucose more rapidly than HbA(1c). Since GA level was related to AGE-related fluorescence and number of glycation sites, it might be a good marker for not only glycemic control of diabetic patients but also structural and functional changes of albumin.
Kisugi
Reiko
R
Division of Central Laboratory, Daisan Hospital, Jikei University School of Medicine, Tokyo, Japan.
Kouzuma
Takuji
T
Yamamoto
Tamotsu
T
Akizuki
Setsuko
S
Miyamoto
Hiroyasu
H
Someya
Yasutoshi
Y
Yokoyama
Junichi
J
Abe
Ikurho
I
Hirai
Noriyuki
N
Ohnishi
Akihiro
A
D001786:Blood Glucose / Q000378:metabolism*; D002853:Chromatography, Liquid; D048909:Diabetes Complications / Q000097:blood* / Q000378:metabolism; D003920:Diabetes Mellitus / Q000097:blood* / Q000378:metabolism; D005260:Female; D005470:Fluorometry; D006442:Glycated Hemoglobin / Q000378:metabolism; D017127:Glycation End Products, Advanced; D006801:Humans; D013058:Mass Spectrometry; D008875:Middle Aged; D012709:Serum Albumin / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism*; D000093423:Glycated Serum Albumin
D001786:Blood Glucose; D006442:Glycated Hemoglobin; D017127:Glycation End Products, Advanced; D012709:Serum Albumin; D000093423:Glycated Serum Albumin