Canagliflozin ameliorates renal oxidative stress and inflammation by stimulating AMPK-Akt-eNOS pathway in the isoprenaline-induced oxidative stress model.

Diabetes is a leading cause of chronic kidney disease, and the high prevalence of sympathetic nervous system (SNS) hyperactivity in diabetic patients makes them further susceptible to SNS-mediated oxidative stress and accelerated kidney damage. Here, we investigated if canagliflozin can reverse isoprenaline (ISO)-induced renal oxidative damage in rats, a model that mimics SNS overstimulation-induced organ injuries in humans. We found that ISO administration elevates renal oxidative stress markers including malondialdehyde (MDA), advanced protein oxidation product (APOP), myeloperoxidase (MPO) and nitric oxide (NO), while depleting levels of endogenous antioxidants such as catalase (CAT), superoxide dismutase (SOD) and glutathione (GSH). Strikingly, canagliflozin treatment of ISO-treated rats not only prevents elevation of oxidative stress markers but also rescues levels of depleted antioxidants. Our results also show that canagliflozin stimulates antioxidant/anti-inflammatory signaling pathways involving AMP-activated protein kinase (AMPK), Akt and eNOS, and inhibits iNOS and NADPH oxidase isoform 4 (NOX4), all of which are associated with oxidative stress and inflammation. Further, canagliflozin prevents ISO-induced apoptosis of kidney cells by inhibiting Bax protein upregulation and caspase-3 activation. Histological examination of kidney sections reveal that canagliflozin attenuates ISO-mediated increases in inflammatory cell infiltration, collagen deposition and fibrosis. Finally, consistent with these findings, canagliflozin treatment improves kidney function in ISO-treated rats, suggesting that the antioxidant effects may be clinically translatable.

High-fat diet-induced metabolic syndrome and oxidative stress in obese rats are ameliorated by yogurt supplementation.

The main objective of this experiment was to determine the effects of yogurt supplementation on fat deposition, oxidative stress, inflammation and fibrosis in the liver of rats with high-fat (HF) diet-induced obesity. Male Wistar rats were used in this study and were separated into the following four different groups: the control, control + yogurt, high fat and high fat+ yogurt groups. The high fat groups received a HF diet for eight weeks. A 5% yogurt (w/w) supplement was also provided to rats fed the HF diet. Yogurt supplementation prevented glucose intolerance and normalized liver-specific enzyme activities in the HF diet-fed rats. Yogurt supplementation also significantly reduced the levels of oxidative stress markers in the plasma and liver of HF diet-fed rats. Moreover, inflammatory cell infiltration, collagen deposition and fibrosis in the liver of HF diet-fed rats were also prevented by yogurt supplementation. Furthermore, yogurt supplementation normalized the intestinal lining and brush border in HF diet-fed rats. This study suggests that yogurt supplementation potentially represents an alternative therapy for the prevention of metabolic syndrome in HF diet-fed rats.

A systematic literature review of the effect of insulin sensitizers on the cognitive symptoms of Alzheimer's Disease in transgenic mice.

CLINICAL IMPLICATION: Alzheimer's Disease (AD) presents as a gradual decline in cognitive function, with its characteristic pathology consisting of Amyloid ß (Aß) accumulation and hyperphosphorylated tau. Impaired insulin signalling was recently found in the brain in AD, and shown to increase AD pathology. Similar insulin resistance is found in type 2 diabetes and is currently treated with insulin sensitizers (IS). AIMS AND METHOD: The aim of this literature review was to evaluate whether IS could effectively reduce AD's characteristic pathology and symptoms in models of AD in transgenic mice. The efficacy of an IS (Metformin, Rosiglitazone or Pioglitazone) at improving each characteristic in transgenic mice was evaluated. RESULTS: A variety of cognitive tests and measures of pathology were utilized to assess these outcomes, hindering comparison. Improvements in cognition, learning and Aß pathology were demonstrated by some papers, and all papers reported a decrease in tau phosphorylation, but no effect on total tau levels.