Advanced glycation end products accelerate rat vascular calcification through RAGE/oxidative stress

Abstract

BackgroundArterial media calcification (AMC) is highly prevalent and is a major cause of morbidity, mortality, stroke and amputation in patients with diabetes mellitus (DM). Previous research suggests that advanced glycation end products (AGEs) are responsible for vascular calcification in diabetic patients. The potential link between oxidative stress and AGEs-induced vascular calcification, however, has not been examined.MethodsMale Wistar rats received a high fat diet for 8 weeks followed by a single dose of streptozotocin to induce DM (DM). Calcification was induced with Vitamin D3 and nicotine (VDN). We started VDN treatment at 1 week after the initial streptozotocin injection (DM+VDN). Age-matched rats were used as controls (CON). Metabolic parameters, aortic calcium content, alkaline phosphatase (ALP) protein, malondialdehyde (MDA) content, Cu/Zn superoxide dismutase (SOD) activity, aorta receptor for advanced glycation end products (RAGE) and aorta AGEs levels were measured. In vitro, vascular smooth muscle cells (VSMCs) were cultured with AGEs in DMEM containing 10 mmol·L-1 ß -glycerophosphate (ß-GP). Calcium content and ALP activity were used to identify osteoblastic differentiation and mineralization. Western blots were used to examine protein expression of Cu/Zn SOD, NADPH oxidase Nox1 and RAGE. In addition, the intracellular reactive oxygen species (ROS) generation was evaluated using fluorescent techniques with dihydroethidine (DHE) method.ResultsThe DM+VDN group showed a significant increase in aortic calcium content, levels of aorta AGEs, MDA content, ALP protein levels and RAGE expression, although Cu/Zn SOD activity decreased significantly. In vitro, enhanced Nox1, RAGE expression as well as the production of intracellular superoxide anions, and reduced expression of Cu/Zn SOD induced by AGEs were attenuated by the anti-RAGE antibody or a ROS inhibitor. Furthermore, the AGEs-stimulated ROS increase was also significantly inhibited by a SOD mimetic. Increased ALP activity and calcium deposition were also inhibited markedly by the ROS inhibitor and the anti-RAGE antibody.ConclusionsThese results suggest that AGEs enhance vascular calcification partly through a RAGE/oxidative stress pathway.

Uremic Toxicity of Advanced Glycation End Products in CKD

“…[109][110][111][112][113] Vascular calcification is an independent predictor of cardiovascular mortality, 114,115 and one of its consequences is altered aortic compliance. 116 119 Moreover, lower sRAGE levels were recently associated with carotid plaque calcification. 76 Arterial stiffness has a major role not only in the increase in systolic BP and pulse pressure, but also in the decrease in diastolic BP.…”

Effects of empagliflozin on blood pressure and markers of arterial stiffness and vascular resistance in patients with type 2 diabetes

“…The metabolic abnormalities that are characteristic of diabetes, such as hyperglycaemia, excess free fatty acids and insulin resistance, can lead to suppression of nitric oxide production and activation of the renin-angiotensin system, leading to oxidative stress, endothelial dysfunction and activation of the receptor for advanced glycation end products (RAGE) [4][5][6]. These may contribute to hypertension [7] or to increased arterial stiffness related to vascular calcification or accumulation of collagen [8,9] that could partly explain the increased risk of vascular complications associated with T2DM [4].…”

“…The risk of CV disease in adults with diabetes is double that in adults without diabetes, and diabetes is estimated to account for 10-12% of all vascular deaths [2]. Patients with T2DM often have numerous CV risk factors and a multifactorial approach to addressing CV risk, including controlling glycaemia, blood pressure (BP) and body weight, is recommended in these patients [1,3].The metabolic abnormalities that are characteristic of diabetes, such as hyperglycaemia, excess free fatty acids and insulin resistance, can lead to suppression of nitric oxide production and activation of the renin-angiotensin system, leading to oxidative stress, endothelial dysfunction and activation of the receptor for advanced glycation end products (RAGE) [4][5][6]. These may contribute to hypertension [7] or to increased arterial stiffness related to vascular calcification or accumulation of…”

Ectopic calcification and bone: a comparison of the effect of dietary carbohydrates, sugars and protein

“…When AGEs come into contact with their receptor (RAGE), intracellular reactive oxygen species (ROS) are generated and mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-kB) signalling is initiated [87] . VSMCs cultured with AGEs showed enhanced production of ROS, upregulated expression of RAGEs and increased phosphorylation of p38 MAPK, as well as increased activity of markers of bone formation: alkaline phosphatase, osteopontin and osteocalcin 88,89 . When an antioxidant or anti-RAGE antibody was added to the medium, ROS expression, p38 MAPK phosphorylation and calcification were reduced and endogenous antioxidant expression increased, suggesting that calcification of VSMCs occurs through a RAGE/oxidative stress pathway via osteoblast-like differentiation of smooth muscle cells 88,89 .…”