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Advanced glycation end products and the pathogenesis of nonalcoholic fatty liver disease in non-diabetic adults

Published online by Cambridge University Press:  24 November 2016

S.A. Palma-Duran
Affiliation:
Human Nutrition, School of Medicine, University of Glasgow, G31 2ER, UK
M.D. Kontogianni
Affiliation:
Department of Nutrition & Dietetics, School of Health Science and Education, Harokopio University, Kallithea, Greece
A. Vlassopoulos
Affiliation:
Human Nutrition, School of Medicine, University of Glasgow, G31 2ER, UK
S. Zhao
Affiliation:
Human Nutrition, School of Medicine, University of Glasgow, G31 2ER, UK
G.V. Papatheodoridis
Affiliation:
2nd Department of Internal Medicine, Athens University Medical School, Hippokration Hospital of Athens, Athens, Greece
E. Combet
Affiliation:
Human Nutrition, School of Medicine, University of Glasgow, G31 2ER, UK
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Abstract

Type
Abstract
Copyright
Copyright © The Authors 2016 

Non-alcoholic fatty liver disease (NALFD) is considered as the hepatic manifestation of the metabolic syndrome, with insulin resistance (IR) as key underlying pathophysiological mechanism. NAFLD comprise a wide range of liver damage, from simple fatty liver to non-alcoholic steatohepatitis (NASH), including cirrhosis(Reference Ratziu, Bellentani and Cortez-Pinto1). Hyperglycemia, IR and oxidative stress increase advance glycation end products (AGEs) that may contribute to the pathophysiology of NAFLD through the AGE-RAGE axis. AGEs such pentosidine, Nɛ-carboxyethyl-L-lysine (CEL) and Nɛ-carboxymethyl-L-lysine (CML) exert pathological effects by binding to AGEs receptors (RAGE), triggering inflammation, cellular dysfunction and cell death. Soluble RAGE (sRAGE) may protect by preventing AGEs/RAGE interaction(Reference Yilmaz, Ulukaya and Gul2). The aim of the study was to evaluate the association of AGEs and sRAGE levels in a case (NAFLD)-control cohort with markers of liver function (ALT, AST, and GGT) and IR.

The study included 131 non-diabetic adults in age, sex and BMI matched pairs based on the presence/absence of NAFLD (liver enzymes and ultrasound hepatic steatosis)(Reference Georgoulis, Kontogianni and Tileli3). AGEs were analysed by liquid chromatography-mass spectrometry (CML, CEL), fluorescence (pentosidine, AGE fluorescence), colorimetry (fructosamine) and ELISA (sRAGE).

Mean values of cases were significantly different from the controls (independent t-test, *P < 0.01 selecting cases if match by age, sex and BMI). a Data are not normally distributed.

Patients’ mean age was 45 year with a BMI of 29 kg/m2. Glycation biomarkers were significantly higher in cases compared to controls, except for CML (p = 0·19). The absence of difference could be explained by the suppressed CML plasma levels observed in overweight subjects, thereby reducing our ability to detect an effect(Reference Delgado-Andrade4). Compared to controls, AGEs were 36 % higher in cirrhosis patients, 18 % higher in NASH and 27 % higher in fatty liver patients (p < 0·01). Two-fold lower sRAGE levels were present in cases and were inversely associated with CEL and AGE fluorescence (r = 0·59, p < 0·01). sRAGE levels were inversely associated with the severity of NAFLD based on liver function and IR (r = 0·44, p < 0·01), and the stage of the disease (r = 0·38, P < 0·001). These findings support the hypothesis that AGEs-RAGE axis is associated with the reduction of hepatic function and highlight their potential as markers of NAFLD progression.

The cross-sectional study was financially supported by the Hellenic Foundation of Gastroenterology & Nutrition. S.P acknowledges receipt of a CONACyT Ph.D. scholarship.

References

1.Ratziu, V, Bellentani, S, Cortez-Pinto, H, et al. (2010). Journal of hepatology. 53, 372384.10.1016/j.jhep.2010.04.008Google Scholar
2.Yilmaz, Y, Ulukaya, E, Gul, OO, et al. (2009). Clin Biochem. 42, 802807.10.1016/j.clinbiochem.2009.02.003Google Scholar
3.Georgoulis, M, Kontogianni, MD, Tileli, N, et al. (2014). Eur J Nutr. 53, 17271735.10.1007/s00394-014-0679-yGoogle Scholar
4.Delgado-Andrade, C (2016). Food Funct. 7, 4657.10.1039/C5FO00918AGoogle Scholar