Abstract
Advanced glycation endproducts have been implicated in the development of diabetic complications. In addition, these products could also mediate certain bone alterations such as diabetic osteopenia. Several receptors specific for advanced glycation endproduct-modified proteins have been characterized in different cell types, contributing to the recognition and degradation of senescent proteins. In the present report, we investigated the possible presence of advanced glycation endproduct-binding proteins on osteoblast-like cells. Both UMR106 and MC3T3E1 cell lines express specific advanced glycation endproduct-binding sites, with an affinity constant between 0.4 and 1.7. 10(6) M(-1), depending on the stage of osteoblastic differentiation; and with a receptor capacity of 1.5-2.0. 10(7) sites/cell. Osteoblast-like cells were also found to participate both in the uptake and degradation of advanced glycation endproduct-modified bovine serum albumin at 37 degrees C. Radiolabelled ligand blotting studies confirmed the presence of several membrane binding proteins, with apparent molecular masses of 50, 45-40, 30, 25 and 18 kDa; the major bands corresponded to 30 and 25 kDa proteins. This study provides evidence of the presence of advanced glycation endproduct-specific binding sites, and for their regulation with the stage of differentiation, in two osteoblast-like cells in culture.
Highlights
In poorly controlled diabetes mellitus, excessive non-enzymatic glycosylation of proteins, lipids and nucleic acids occurs as a consequence of hyperglycaemia
Advanced glycation endproducts have been implicated in the development of chronic complications of diabetes, such as nephropathy, retinopathy, neuropathy and macrovascular disease [1]
Several lines of evidence have recently suggested that advanced glycation endproducts (AGEs) could contribute to the osteopenia found in poorly compensated patients with type 1 diabetes
Summary
In poorly controlled diabetes mellitus, excessive non-enzymatic glycosylation (glycation) of proteins, lipids and nucleic acids occurs as a consequence of hyperglycaemia. During this process, a reducing sugar such as glucose initially reacts reversibly with a free amino group, resulting in the formation of a Schiff base. Amadori products can irreversibly progress to the formation of a family of cross-linked and fluorescent compounds, collectively known as advanced glycation endproducts (AGEs) [1, 2]. Since the formation of AGEs is essentially irreversible, they continue to accumulate over the years, in long-lived structural proteins of insulin-independent tissues [3, 4]. These highly reactive peptides have been implicated in the pathogenesis of haemodialysis-associated amyloidosis, through secondary AGE-modification of β-2 microglobulin [7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
