The effects of walnut supplementation on hippocampal NMDA receptor subunits NR2A and NR2B of rats.

OBJECTIVES: Walnuts contain numerous selected dietary factors that have an impact on brain functions, especially learning and memory formation in the hippocampus. Hippocampal N-methyl d-aspartate receptors (NMDARs) are involved in the formation of cognitive functions. In this study, we aimed to investigate the molecular effects of walnut supplementation on the hippocampal expressions of NMDARs involved in cognitive functions and lipid peroxidation levels in rats. METHODS: The male Sprague-Dawley rats (6 months old, n = 24) were fed with a walnut-supplemented diet (6% walnut diet, n = 12) and a control diet (rat food, n = 12) as ad libitum for 8 weeks. At the end of this period, NMDAR subunits NR2A and NR2B in the hippocampi were assayed by western blotting. Lipid peroxidation levels were measured using the thiobarbituric acid. RESULTS: The expression of NR2A and NR2B was elevated in the walnut-supplemented rats compared with the control group (P < 0.05). In addition, the levels of lipid peroxidation in the walnut-supplemented group were significantly decreased compared with the control group. DISCUSSION: We suggested that walnut supplementation may have protective effects against the decline of cognitive functions by regulating NMDAR and lipid peroxidation levels in the hippocampus. The study provides evidence that selected dietary factors (polyunsaturated fatty acids, melatonin, vitamin E, and flavonoids) within walnut may help to trigger hippocampal neuronal signal transduction for the formation of learning and memory.

Calorie restriction modulates hippocampal NMDA receptors in diet-induced obese rats.

Calorie restriction (CR) has attracted increased interest since CR enhances lifespan and alters age-related decline in hippocampal-dependent cognitive functions. Obesity is associated with poor neurocognitive outcome including impaired hippocampal synaptic plasticity and cognitive abilities such as learning and memory. N-Methyl-D-aspartate receptors (NMDARs) are linked to hippocampal-dependent learning and memory, which may be stabilized by CR. In the present study, we aimed to establish the effects of CR on NMDARs in CA1 region of hippocampus in obese and non-obese rats. In addition, malondialdehyde (MDA) levels were determined as a marker for lipid peroxidation (LPO) in hippocampus. Four groups were constituted as control group (C, n = 9), obese group (OB, n = 10), obese calorie-restricted group (OCR, n = 9), and non-obese calorie-restricted group (NCR, n = 10). OCR and NCR were fed with a 60% CR diet for 10 weeks. After 10 weeks of CR, the MDA levels significantly decreased in the calorie-restricted groups. Obesity caused significant decreases in NR2A and NR2B subunit expressions in the hippocampus. The hippocampal NR2A and NR2B levels significantly increased in the OCR group compared with the OB group (P < 0.05). In contrast, the hippocampal NR2A and NR2B levels significantly decreased in the NCR group compared with the C group (P < 0.05). Oxidative stress can be prevented by CR, and these data may provide a molecular and cellular mechanism by which CR may regulate NMDAR-mediated response against obesity-induced changes in the hippocampus.

Pro-inflammatory cytokine levels in association between periodontal disease and hyperlipidaemia.

AIM: The aim of this study was to evaluate serum and gingival crevicular fluid (GCF) pro-inflammatory cytokine levels in association between periodontal disease and hyperlipidaemia. MATERIAL AND METHODS: One hundred and twenty-three subjects with hyperlipidaemia and 68 systemically healthy controls (C) were included in the study. Hyperlipidaemic groups were divided into two groups as suggested diet (HD) and prescribed statin (HS). Both groups were divided into three subgroups as healthy (h), gingivitis (g) and periodontitis (p). The clinical periodontal parameters, fasting venous blood and GCF samples were obtained, and serum tumour necrosis factor-alpha (TNF-α), interleukin (IL)-1ß (IL-1ß) and IL-6 levels were evaluated. RESULTS: The ratio of total cholesterol to high-density lipoprotein (TC/HDL) was associated with gingival index and percentage of bleeding on probing (BOP%) in both hyperlipidaemic groups. In HS group, GCF and serum IL-6 were positively correlated with BOP% and TC/HDL. GCF TNF-α was positively associated with probing pocket depth and clinical attachment level, whereas serum TNF-α was associated with BOP% in the HD group. Serum and GCF TNF-α and IL-1ß were significantly associated with TC/HDL in the HD group. CONCLUSIONS: Serum pro-inflammatory cytokines may play an important role in the association between periodontal disease and hyperlipidaemia.

Evaluation of angiogenesis with vascular endothelial growth factor in patients with thalassemia major.

BACKGROUND: Thalassemia major (TM) is an important cause of severe anemia that necessitates regular blood transfusion to prevent the profound weakness and cardiac decompensation caused by the anemia. However, iron overloading is an inevitable consequence of prolonged transfusion therapy. In addition, extramedullary hematopoiesis and hemosiderosis cause spleen, liver and marrow enlargement. In recent years the role of angiogenesis has been investigated in physiological and pathological conditions. However, it is known that angiogenetic factors, especially the vascular endothelial growth factor (VEGF), cause differentiation of the hemangioblast. METHODS: The effect of angiogenesis hasn't been investigated in TM patients yet, and in this study, angiogenesis was researched in 43 thalassemic patients by serum VEGF measurement. RESULTS: VEGF levels were not affected by hemoglobin levels, ferritin levels, or chelation type (P > 0.05). However, VEGF was positively affected by chelation starting age and negatively affected by yearly transfusion requirement of TM patients (P < 0.05). In addition, VEGF of patients who underwent splenectomy were higher than those who didn't undergo splenectomy (P < 0.05). CONCLUSION: Early chelating age will negatively influence the VEGF level, which increases angiogenesis, however, early starting transfusion age and regular blood transfusion will positively influence the VEGF level, which decreases angiogenesis in thalassemic patients.

Renal deterioration caused by carcinogens as a consequence of free radical mediated tissue damage: a review of the protective action of melatonin.

This brief review summarizes some of the publications that document the preventive role of melatonin in kidney damage caused by carcinogens such as 2-nitropropane, arsenic, carbon tetrachloride, nitrilotriacetic acid and potassium bromate. Numerous chemicals generate excessive free radicals that eventually induce renal worsening. Melatonin partially or totally prevents free radical mediated tissue damages induced by many carcinogens. Protective actions of melatonin against the harmful effects of carcinogens are believed to stem from its direct free radical scavenging and indirect antioxidant activities. Dietary or pharmacologically given melatonin may attenuate the oxidative stress, thereby mitigating the subsequent renal damage.