Impact of enriched environment on production of tau, amyloid precursor protein and, amyloid-ß peptide in high-fat and high-sucrose-fed rats.

OBJECTIVE: The Western-type diet is associated with an elevated risk of Alzheimer's disease and other milder forms of cognitive impairment. The aim of the present study was to investigate the effects of the environmental enrichment on amyloid and tau pathology in high-fat and high-sucrose-fed rats. METHODS: In total, 40 adult male rats were categorised into two main groups according to their housing conditions: enriched environment (EE, n=16) and standard housing condition (n=24). The groups were further divided into five subgroups that received standard diet, high-fat diet, and high-sucrose diet. We performed the analysis of amyloid ß-peptide (Aß) (1-40), Aß(1-42), amyloid precursor protein (APP), and tau levels in the hippocampus of rats that were maintained under standard housing conditions or exposed to an EE. RESULTS: The EE decreased the Aß(1-40), Aß(1-42), APP, and tau levels in high-fat and high-sucrose-fed rats. CONCLUSION: This observation shows that EE may rescue diet-induced amyloid and tau pathology.

Environmental enrichment reverses cognitive impairments provoked by Western diet in rats: Role of corticosteroid receptors.

AIMS: Previous studies demonstrated that the Western diet (WD), which is rich in saturated fat (HFD) and refined sugar (HSU), is related to the impairments of hippocampus-dependent learning and memory and forebrain synaptic plasticity in rodents. The environmental enrichment (EE) has been shown to enhance learning and memory in the HFD-induced cognitive deficits, but the exact mechanism is still not clearly understood. Therefore, the present study aimed to clarify the effects of the EE on spatial memory in WD-fed rats, and to analyze the potential role of corticosteroid receptors in the EE conditioning. MAIN METHODS: Male Wistar albino rats were housed in either an enriched or standard environment and fed with the HFD (35% of energy as fat), HSU (100% of carbohydrate as sucrose) or standard rat chow for 4weeks. We used the Morris' water maze test (MWM) to assess the learning and memory performance, and measured plasma levels of corticosterone (CORT) and adrenocorticotropic hormone (ACTH), as well as glucocorticoid (GR) and mineralocorticoid receptor (MR) levels in the hippocampus. KEY FINDINGS: The results showed that HFD-fed rats displayed poorer learning and memory performance evaluated with MWM than controls. The EE reversed the cognitive deficits caused by the HFD. In addition, the EE resulted in an increase of GR and MR levels without affecting plasma CORT and ACTH concentrations. SIGNIFICANCE: Based on these findings, it could be suggested that the EE plays an important role in amelioration of the HFD-induced cognitive impairments, but this intervention is independent of the hypothalamic-pituitary-adrenal axis and hippocampal corticosteroid receptor levels.

Antidepressant-like effects of quercetin in diabetic rats are independent of hypothalamic-pituitary-adrenal axis.

OBJECTIVE: Quercetin, one of the most potent flavonol in the family of flavonoids, has been shown to have benefits against diabetes and its complications. In the present study, we investigated effects of quercetin on depression-like behaviours and hypothalamic-pituitary-adrenal (HPA) axis in diabetic rats. METHODS: Experimental diabetes was induced by using streptozotocin, and either 50 or 100 mg/kg quercetin was intraperitoneally administered for 21 days. Following the last treatment, animals were subjected to the forced swim test, and subsequently, the blood was obtained by cardiac puncture to measure plasma adrenocorticotropic hormone (ACTH) and corticosterone (CORT) levels. RESULTS: A significant increase of the total immobile time, accompanied by a decrease in the immobility latency, which suggests a depressive status, was observed in diabetic animals that was reversed by the treatment of 50 mg/kg quercetin. However, the higher dose of quercetin (100 mg/kg) was ineffective in alleviating depression-like behaviours. The plasma concentrations of ACTH, and total- and free-CORT were not affected by both doses of quercetin. CONCLUSION: Therefore, we concluded that the antidepressant-like effects of quercetin in diabetes are independent of the HPA axis.

Effects of coenzyme Q10 supplementation on plasma adiponectin, interleukin-6, and tumor necrosis factor-alpha levels in men.

The aim of the study was to determine the effects of coenzyme Q10 supplementation on plasma adiponectin, interleukin (IL)-6, and tumor necrosis factor (TNF )-alpha levels in sedentary men. Fourteen healthy, nonsmoking, sedentary men participated in the study. The protocol was approved by the Ethical Committee of our institution. This study was a randomized, double-blind, crossover trial. Blood samples were collected from all participants before coenzyme Q10 or placebo supplementation. The participants were randomly allocated to two groups. Seven participants received oral coenzyme Q10 (100 mg/day) supplementation, and seven participants received placebo (glucose) for 8 weeks. At the end of the 8 weeks, a second blood sampling was performed. After a 4-week washout period, placebo was given to the participants who used coenzyme Q10 the first time, and vice versa, and blood sampling was repeated. Plasma was stored at -80 degrees C until the time of analysis for adiponectin, IL-6, and TNF-alpha. Both CoQ10 and placebo supplementation did not affect plasma adiponectin and TNF-alpha levels. IL-6 level increased with coenzyme Q10 supplementation, but this increase did not differ from that seen with placebo supplementation. Coenzyme Q10 supplementation did not affect plasma adiponectin, IL-6, and TNF-alpha levels in sedentary men.

Increased homocysteine in heart failure: a result of renal impairment?

BACKGROUND: Hyperhomocysteinemia may constitute a risk factor for patients with severe heart failure. This study examines the relationship between plasma homocysteine concentration and left ventricular ejection fraction with renal function in heart failure patients free of coronary artery disease. METHODS: Left ventricular ejection fraction was documented in 62 patients with advanced heart failure who had no proven significant coronary artery stenosis. Glomerular filtration rate was measured using the Cockroft-Gault equation. RESULTS: Elevated homocysteine levels (>or=15 micromol/L) were detected in 22 patients. Low glomerular filtration rate was observed in patients who had normal serum creatinine concentration. Homocysteine was strongly correlated with age, duration of disease, left ventricular ejection fraction, serum creatinine, and glomerular filtration rate. Statistically significant trends were observed across respective homocysteine quartiles. However, by multivariate regression, the strongest predictor of homocysteine was the glomerular filtration rate. CONCLUSIONS: Impaired renal function leads to a diminished clearance rate, which can be a prominent pathophysiological mechanism in the elevation of homocysteine concentration in heart failure.

Elevated serum nitric oxide and superoxide dismutase in euthymic bipolar patients: impact of past episodes.

Nitric oxide (NO) has been implicated to play a role in the pathogenesis of many neuropsychiatric disorders. NO level was found high in acute manic inpatients. In this study, we aimed to assess NO level and activity of the antioxidant enzyme, superoxide dismutase (SOD), in euthymic bipolar patients. Twenty-seven patients with bipolar disorder (BD) in euthymic phase, and 20 healthy volunteers were included in this study. A semi-structured form was used to note social, demographic and clinical parameters of the patients. NO level and SOD activity were studied in the serum samples obtained from the patients and controls. The mean serum NO level in BD was significantly higher than in controls. Mean serum SOD activity was found to be elevated in patients with BD compared to controls. Total number of the manic episodes correlated with NO levels, but not with SOD activity. In conclusion, the number of manic episodes is positively associated with NO levels. NO and SOD appear to have a pathophysiological role in BD, especially in Type I euthymic phase, and may be considered an available trait marker for BD.