Determination of advanced glycation end-products and antibodies against them (anti-CML and anti-CEL) in the serum of Graves' orbitopathy patients before and after methylprednisolone treatment.

Abstract

The glycation process is a non-enzymatic modification of proteins occurring due to the reactions of reductive carbohydrates. The glycated residues lose their biological functions, and their removal process is ineffective. They accumulate, and as a result they cause an immunological response. The aim of this study was a determination of the concentrations of advanced glycation end-products and antibodies against carboxymethyl lysine (anti-CML) and carboxyethyl lysine (anti-CEL) in the sera of Graves' orbitopathy patients. The study group were patients from the Division of Endocrinology of the Medical University of Silesia (n = 25) suffering from Graves' orbitopathy. The concentration of AGE-peptides using flow spectrofluorimetry method, and anti-CML and anti-CEL IgG antibodies using immunoenzymatic technique (ELISA), were measured in patients sera before and after methylprednisolone treatment. In sera of the study group the concentrations of AGE-peptides and anti-CML were significantly lower before and after treatment in comparison to the control group (p < 0.05). Mean values of anti-CEL concentrations were comparable (at both phases of treatment) with the value observed in the control group. After treatment the concentrations of AGE-peptides and anti-CEL significantly decreased (p < 0.05); however, the concentration of anti-CML was also lower but the observed change was not significant (p > 0.05). In the course of Graves' orbitopathy the glycation process is disturbed. The treatment modifies significantly the process by lowering the concentration of advanced glycation end-products and suppressing the immune response to them. (Endokrynol Pol 2016; 67 (4): 383-389).