N-Acetyl Cysteine Attenuated the Deleterious Effects of Advanced Glycation End-Products on the Kidney of Non-Diabetic Rats
CELLULAR PHYSIOLOGY AND BIOCHEMISTRY
Authors: Thieme, Karina; Da Silva, Karolline S.; Fabre, Nelly T.; Catanozi, Sergio; Monteiro, Maria Beatriz; Santos-Bezerra, Daniele Pereira; Costa-Pessoa, Juliana Martins; Oliveira-Souza, Maria; Machado, Ubiratan F.; Passarelli, Marisa; Correa-Giannella, Maria Lucia
Abstract
Aim: To assess the renal effects of chronic exposure to advanced glycation end-products (AGEs) in the absence of diabetes and the potential impact of concomitant treatment with the antioxidant N-acetyl cysteine (NAC). Methods: Wistar rats received intraperitoneally 20 mg/kg/day of albumin modified (AIbAGE) or not (AIbC) by advanced glycation for 12 weeks and oral NAC (600mg/L; AIbAGE+NAC and AlbC+NAC, respectively). Biochemical, urinary and renal morphological analyses; carboxymethyl-lysine (CML, an AGE), CD68 (macrophage infiltration), and 4-hydroxynonenal (4-HNE, marker of oxidative stress) immunostaining; intrarenal mRNA expression of genes belonging to pathways related to AGEs (Ager, Ddost, Nfkb1), renin-angiotensin system (Agt, Ren, Ace), fibrosis (Tgfb1, Col4a1), oxidative stress (Nox4, Txnip), and apoptosis (Box, Bcl2); and reactive oxidative species (ROS) content were performed. Results: AIbAGE significantly increased urine protein-to-creatinine ratio; glomerular area; renal CML content and macrophage infiltration; expression of Ager, Nfkb1, Agt, Ren, Tgfb1, Col4a1, Txnip, Bax/Bcl2 ratio; and 4-HNE and ROS contents. Some of these effects were attenuated by NAC concomitant treatment. Conclusion: Because AGEs are highly consumed in modern diets and implicated in the progression of different kidney diseases, NAC could be a therapeutic intervention to decrease renal damage, considering that long-term restriction of dietary AGEs is difficult to achieve in practice. (C) 2016 The Author(s) Published by S. Karger AG, Basel
Increased liver AGEs induce hepatic injury mediated through an OST48 pathway
SCIENTIFIC REPORTS
Authors: Zhuang, Aowen; Yap, Felicia Yt.; Bruce, Clinton; Leung, Chris; Plan, Manuel R.; Sullivan, Mitchell A.; Herath, Chandana; McCarthy, Domenica; Sourris, Karly C.; Kantharidis, Phillip; Coughlan, Melinda T.; Febbraio, Mark A.; Hodson, Mark P.; Watt, Matthew J.; Angus, Peter; Schulz, Benjamin L.; Forbes, Josephine M.
Abstract
The protein oligosaccharyltransferase-48 (OST48) is integral to protein N-glycosylation in the endoplasmic reticulum (ER) but is also postulated to act as a membrane localised clearance receptor for advanced glycation end-products (AGE). Hepatic ER stress and AGE accumulation are each implicated in liver injury. Hence the objective of this study was to increase the expression of OST48 and examine the effects on hepatic function and structure. Groups of 8 week old male mice (n = 10-12/group) over-expressing the gene for OST48, dolichyl-diphosphooligosaccharide- protein glycosyltransferase (DDOST+/-), were followed for 24 weeks, while randomised to diets either low or high in AGE content. By week 24 of the study, either increasing OST48 expression or consumption of high AGE diet impaired liver function and modestly increased hepatic fibrosis, but their combination significantly exacerbated liver injury in the absence of steatosis. DDOST+/- mice had increased both portal delivery and accumulation of hepatic AGEs leading to central adiposity, insulin secretory defects, shifted fuel usage to fatty and ketoacids, as well as hepatic glycogen accumulation causing hepatomegaly along with hepatic ER and oxidative stress. This study revealed a novel role of the OST48 and AGE axis in hepatic injury through ER stress, changes in fuel utilisation and glucose intolerance.