Levels of anti-fructose-modified HSA antibodies correlate with disease status in diabetic subjects

Int J Biol Macromol. 2016 Jul:88:93-101. doi: 10.1016/j.ijbiomac.2016.03.052. Epub 2016 Mar 25.

Abstract

Objective: This study aimed to assess the changes induced in HSA upon fructose-modification and to use the modified protein as an antigen for studying the presence of antibodies in diabetic patients. Further, magnitude of oxidative stress was also assessed.

Methods: HSA was modified with fructose, changes induced were studied by DSC measurements and near-UV CD. The binding characteristics of antibodies in the sera of diabetes patients to native and modified-HSA was assessed by ELISA and band shift assay. The oxidative stress in these patients was studied by carbonyl content estimation, FRAP assay and TBARS determination

Results: DSC revealed that fructose modified-HSA was more thermostable than its native form. Changes in tertiary structure of fructose-modified HSA were seen in near-UV CD. Patient studies showed that fructose-modified HSA acts as a potent immunogen compared to its native form and the levels of antibodies against fructose-modified HSA served as a parameter for tracking the glycemic control and oxidative stress parameters (carbonyl content, FRAP value and MDA level) in diabetic patients.

Conclusions: Fructose-modification of HSA causes perturbations in its structure and function, thereby, making the protein antigenic besides decreasing its antioxidant capacity. This study suggests that fructose-modified-HSA is an important contributor in diabetic pathophysiology.

Keywords: Diabetes mellitus; Fructose; Hyperglycemia.

MeSH terms

  • Antibodies / blood*
  • Antibody Affinity
  • Antibody Specificity
  • Diabetes Mellitus, Type 1 / blood
  • Diabetes Mellitus, Type 1 / diagnosis*
  • Diabetes Mellitus, Type 1 / immunology
  • Diabetes Mellitus, Type 1 / physiopathology
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / diagnosis*
  • Diabetes Mellitus, Type 2 / immunology
  • Diabetes Mellitus, Type 2 / physiopathology
  • Electrophoretic Mobility Shift Assay
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Fructose / chemistry*
  • Fructose / immunology
  • Glycosylation
  • Humans
  • Hyperglycemia / blood
  • Hyperglycemia / diagnosis*
  • Hyperglycemia / immunology
  • Hyperglycemia / physiopathology
  • Immune Sera / analysis*
  • Male
  • Oxidation-Reduction
  • Oxidative Stress / immunology
  • Protein Carbonylation / immunology
  • Protein Stability
  • Protein Structure, Tertiary
  • Serum Albumin / chemistry*
  • Serum Albumin / immunology
  • Thiobarbituric Acid Reactive Substances / metabolism

Substances

  • Antibodies
  • Immune Sera
  • Serum Albumin
  • Thiobarbituric Acid Reactive Substances
  • Fructose