Nitrones reverse hyperglycemia-induced endothelial dysfunction in bovine aortic endothelial cells

Abstract

Hyperglycemia has been implicated in the development of endothelial dysfunction through heightened ROS production. Since nitrones reverse eNOS dysfunction, increase antioxidant enzyme activity, and suppress pro-apoptotic signaling pathway and mitochondrial dysfunction from ROS-induced toxicity, the objective of this study was to determine whether nitrone spin traps DMPO, PBN and PBN-LA were effective at duplicating these effects and improving glucose uptake in an in vitro model of hyperglycemia-induced dysfunction using bovine aortic endothelial cells (BAEC). BAEC were cultured in DMEM medium with low (5.5 mM glucose, LG) or high glucose (50 mM, HG) for 14 days to model in vivo hyperglycemia as experienced in humans with metabolic disease. Improvements in cell viability, intracellular oxidative stress, NO and tetrahydrobiopterin levels, mitochondrial membrane potential, glucose transport, and activity of antioxidant enzymes were measured from single treatment of BAEC cells with nitrones for 24 h after hyperglycemia. Chronic hyperglycemia significantly increased intracellular ROS by 50%, decreased cell viability by 25%, reduced NO bioavailability by 50%, and decreased BH4 levels by 15% thereby decreasing NO production. Intracellular glucose transport and SOD activity were also decreased by 50% and 25% respectively. Nitrone (PBN and DMPO, 50 μM) treatment of BAEC cells grown in hyperglycemic conditions resulted in in the normalization of outcome measures except for SOD and catalase activities. Our findings demonstrate that the nitrones reverse the deleterious effects of hyperglycemia in BAEC cells. We believe that in vivo testing of these nitrone compounds in models of cardiometabolic disease is warranted.

Enhanced Renal Afferent Arteriolar Reactive Oxygen Species and Contractility to Endothelin-1 Are Associated with Canonical Wnt Signaling in Diabetic Mice

“…The reduction in SOD2 may underline the finding that mitochondria are the main site of producing superoxide in diabetes [ 31 , 32 ], Since SOD2 plays a central role in metabolizing O 2 .− in mitochondria the maintained level of SOD1 may prevent O 2 .− overproduction in diabetic conditions. Interestingly, SOD activity in vascular beds showed an increase [ 33 ] or decrease [ 34 , 35 ] in different animal models of diabetes. Likewise, vascular catalase activity or protein level also have been reported to be increased or decreased in diabetes [ 34 , 36 , 37 ], These inconsistent results perhaps depend on the stage or severity of the diabetic model.…”

“…Interestingly, SOD activity in vascular beds showed an increase [ 33 ] or decrease [ 34 , 35 ] in different animal models of diabetes. Likewise, vascular catalase activity or protein level also have been reported to be increased or decreased in diabetes [ 34 , 36 , 37 ], These inconsistent results perhaps depend on the stage or severity of the diabetic model. Our study clearly demonstrates a comprised antioxidant SOD and catalase system in the vasculature of diabetic mice that could contribute to the increases in O 2 .− and H 2 O 2 .…”

NO and HNO donors, nitrones, and nitroxides: Past, present, and future

“…Derivative 31 protected erythrocytes against exogenous free radicals, outperforming parent compounds PBN and lipoic acid . Treatment of BAEC with PBN–LA for 24 hr protected cells from hyperglycemia‐mediated cytotoxicity . Generally, PBN‐LA treatment in BAEC showed improved cell viability, lowered ROS production, decreased mitochondrial membrane potential polarization, improved glucose uptake, and enhanced reduced‐thiol levels.…”

“…Generally, PBN‐LA treatment in BAEC showed improved cell viability, lowered ROS production, decreased mitochondrial membrane potential polarization, improved glucose uptake, and enhanced reduced‐thiol levels. However, no significant effects were observed regarding superoxide dismutase (SOD) and CAT activity under high glucose conditions …”

Diallyl trisulfide attenuates hyperglycemia-induced endothelial apoptosis by inhibition of Drp1-mediated mitochondrial fission

“…Endothelial dysfunction is considered as a pivotal step in atherosclerosis occurrence in diabetes patients [5]. Previous studies have shown that hyperglycemia in diabetes patients leads to endothelial dysfunction and increased production of reactive oxygen species (ROS) [6, 7]. Nicotinamide adenine dinucleotide phosphate oxidases, uncoupled nitric oxide synthases (eNOS), and the mitochondria are the main sources of ROS production [8].…”