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Arch Biochem Biophys. 2018 Jun 1;647:54-66. doi: 10.1016/j.abb.2018.02.004. Epub 2018 Feb 11.

Effect of glycated insulin on the blood-brain barrier permeability: An in vitro study.

Author information

1
Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.
2
Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran. Electronic address: ghriazi@ut.ac.ir.
3
Department of Tissue Engineering and Advanced Cell Culture, Pioneer Research Anahita Company, Pardis Technology Park, Tehran, Iran.
4
Faculty of Basic Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran.
5
Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran; Department of Life Science Engineering, Faculty of New Sciences & Technologies, University of Tehran, Tehran, Iran.

Abstract

Altered blood-brain barrier (BBB) permeability may contribute to pathogenesis of diabetes-related central nervous system disorders. Considering the presence of glycated insulin in plasma of type 2 diabetic patients, we hypothesized that glycated insulin could induce changes in paracellular permeability in BBB. Therefore, the authors decided to study the effect of glycated insulin on paracellular permeability in a BBB model and the change induced in insulin conformation upon glycation. In this study, the structural modification was examined by fluorescence and circular dichroism spectroscopies and dynamic light scattering. Cell proliferation and production of ROS in astrocytes and HUVEC cells were analyzed by MTT and spectrofluorometric assays, respectively. Apoptosis induction was determined and confirmed by flow cytometry and western blot analyses, respectively. The permeability was measured Lucifer yellow and FITC-Dextran. According to our results, glycated insulin presented altered conformation and more exposed hydrophobic patches than insulin. Formation of oligomeric species and advanced glycated end products (AGEs) were determined. Lower cell viability, higher apoptosis, and more ROS were detected upon treatment of cells with glycated insulin. Finally, glycated insulin led to increased Lucifer yellow and FITC-dextran transportation across the BBB model which could result from ROS producing and apoptosis-inducing activities of AGE-insulin.

KEYWORDS:

AGE products; Blood-brain barrier; Glycated insulin; Permeability; Type 2 diabetes

PMID:
29444458
DOI:
10.1016/j.abb.2018.02.004
[Indexed for MEDLINE]

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