TITLE

Identification of Amadori-modified plasma proteins in type 2 diabetes and the effect of short-term intensive insulin treatment

AUTHOR(S)
Jaleel, Abdul; Halvatsiotis, Panagiotis; Williamson, Brian; Juhasz, Peter; Martin, Stephen; Nair, K. Sreekumaran
PUB. DATE
March 2005
SOURCE
Diabetes Care;Mar2005, Vol. 28 Issue 3, p645
SOURCE TYPE
Academic Journal
DOC. TYPE
journal article
ABSTRACT
OBJECTIVE -- Growing evidence supports that nonenzymatic glycation products may cause hyperglycemia-induced diabetes complications. Amadori-modified proteins are the intermediate products of nonenzymatic glycation and constitute the forms of glycated proteins in diabetes. The objective of the current study was to utilize two-dimensional gel electrophoresis, Western blot, and mass spectrometry to identify Amadori-modified plasma proteins in type 2 diabetic patients with poor glycemic control and assess the impact of short-term insulin treatment on the glycation of these proteins. RESEARCH DESIGN AND METHODS -- We compared eight type 2 diabetic subjects (aged 56 ± 3 years and BMI 29.7 ± 0.9 kg/m²) with an average diabetes duration of 8.5 years (range 3-19) with equal numbers of weight-matched (aged 56 ± 2 years and BMI 30.1 ± 10.0 kg/m²) and lean (aged 58 ± 2 years and BMI 25 ± 00.5 kg/m²) nondiabetic subjects who have no first-degree relatives with diabetes. Two separate blood samples were collected from the type 2 diabetic subjects, one following 2 weeks of withdrawal of all antidiabetic medications (T[sub 2]D-; plasma glucose 12.6 ± 1.0 mmol/l) and another following 10 days of intensive insulin treatment (T[sub 2]D+; plasma glucose 5.5 ± 0.2 mmol/l). Plasma proteins were separated using single and two-dimensional gel electrophoresis. Western blot analysis was performed, and several proteins, which reacted with the Amadori-antibody (1-deoxyfructosyl lysine), were identified by tandem mass spectrometry. RESULTS -- No significant differences in the glycation of proteins between the obese and lean groups were noted, but type 2 diabetic patients had several proteins with higher glycation than the control groups. We identified 12 plasma proteins with reduced reaction to the anti-Amadori antibody upon intensive insulin treatment. A significant (P < 0.03) difference in Amadori modification was observed between the T[sub 2]D- and control subjects for all these proteins except the Ig light chain. Insulin treatment reduced Amadori modification of albumin (23.2%, P < 0.02), fibrin (34.6%, P < 0.001), Ig heavy chain constant region (20.7%, P < 0.05), transferrin (25.4%, P < 0.04), and Ig light chain (13%, P < 0.02). In addition, Western blot analysis of two-dimensional gel electrophoresis identified α-fibrinogen precursor, β-fibrinogen precursor, fibrinogen γ-B chain precursor, hemopexin, vitamin D binding protein, and serine protease inhibitor as proteins with a reduced reaction to anti-Amadori antibody upon intensive insulin treatment. CONCLUSIONS -- The current approach offers the opportunity to identify Amadori modification of many proteins that may cause functional alterations and offers the potential for monitoring short-term glycemic control in diabetic patients.
ACCESSION #
16563454

 

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