Our findings indicated that the combination of lycopene and vitamin E antioxidants acted in a synergistic fashion to bring significant effects against oxidative stress in tauopathies.

Hypobaric hypoxia (HH) leads to reduced oxygen delivery to brain. It could trigger cognitive dysfunction and increase the risk of dementia including Alzheimer's disease (AD). The present study was undertaken in order to examine whether B vitamins (B6, B12, folate, and choline) could exert protective effects on hypoxia-induced memory deficit and AD related molecular events in mice. Adult male Kunming mice were assigned to five groups: normoxic control, hypoxic model (HH), hypoxia+vitamin B6/B12/folate (HB), hypoxia+choline (HC), hypoxia+vitamin B6/B12/folate+choline (HBC). Mice in the hypoxia, HB, HC, and HBC groups were exposed to hypobaric hypoxia for 8 h/day for 28 days in a decompression chamber mimicking 5500 meters of high altitude. Spatial and passive memories were assessed by radial arm and step-through passive test, respectively. Levels of tau and glycogen synthase kinase (GSK)-3β phosphorylation were detected by western blot. Homocysteine (Hcy) concentrations were determined using enzymatic cycling assay. Mice in the HH group exhibited significant spatial working and passive memory impairment, increased tau phosphorylation at Thr181, Ser262, Ser202/Thr205, and Ser396 in the cortex and hippocampus, and elevated Hcy levels compared with controls. Concomitantly, the levels of Ser9-phosphorylated GSK-3β were significantly decreased in brain after hypoxic treatment. Supplementations of vitamin B6/B12/folate+choline could significantly ameliorate the hypoxia-induced memory deficits, observably decreased Hcy concentrations in serum, and markedly attenuated tau hyperphosphorylation at multiple AD-related sites through upregulating inhibitory Ser9-phosphorylated GSK-3β. Our finding give further insight into combined neuroprotective effects of vitamin B6, B12, folate, and choline on brain against hypoxia.

Zhang, Zhiqing, Zhonghai Xiao, Bingnan Deng, Xiaohua Liu, Wei Liu, Hongjing Nie, Xi Li, Zhaoli Chen, Danfeng Yang, and Ruifeng Duan. Therapeutic efficacy of methazolamide against intermittent hypoxia-induced excessive erythrocytosis in rats. High Alt Med Biol 19:69-80, 2018.-This study aimed to determine whether methazolamide is effective for the treatment of chronic mountain sickness. Forty-eight male Wistar rats were randomly divided into eight groups: normoxia control, hypoxia control, hypoxia + acetazolamide (30 mg·kg·d), and five hypoxia + methazolamide groups (5, 10, 30, 90, and 120 mg·kg·d). Excessive erythrocytosis was induced through 4 weeks of hypobaric hypoxia (8 hours O 10%/16 hours O 21%). Rats were then treated for 4 weeks, and their body weight was measured. Hematological, hemorheological, and biochemical parameters were analyzed. Renal hypoxia-inducible factor-1alpha (HIF-1α) and vascular endothelial growth factor (VEGF) levels were detected by immunohistochemistry. Proteomic analysis of plasma was conducted to determine the most differentially expressed proteins. Methazolamide with doses lower than 30 mg·kg·d had no significant effects on body weight compared with the hypoxia control group (p > 0.05). Methazolamide dose-dependently reduced the hemoglobin concentration, hematocrit (Hct), and blood viscosity. Hct/blood viscosity, an oxygen delivery index, dose-dependently increased after methazolamide treatment. A methazolamide dose of 10 mg·kg·d showed similar efficacy to an acetazolamide dose of 30 mg·kg·d for all the above parameters. Plasma levels of low-density lipoprotein cholesterol, total cholesterol, creatinine, and hemoglobin increased substantially after long-term hypoxia, but decreased after methazolamide treatment. HIF-1α and VEGF both increased substantially after long-term hypoxia and decreased in the kidney after methazolamide treatment. The most differentially expressed protein was haptoglobin, an endogenous protective factor, which was depleted in rats with excessive erythrocytosis and increased substantially after methazolamide treatment. In summary, methazolamide exhibits dose-dependent efficacy for the treatment of excessive erythrocytosis induced by long-term hypoxia. It also has beneficial effects on oxygen transport and lipid metabolism, which are encouraging with regard to the development of methazolamide-based chronic mountain sickness therapies.

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The present study aimed to examine the effects of hypoxia and cold on vascular endothelial cells (VECs), as well as the protective ability of novel VECs-protective drugs against these injuries. A rat model simulating exposure to hypoxia and cold at high altitude environments was established. Based on these animal experiments, rat aortic VECs were established as injury models and exposed to hypoxia and/or adrenaline (ADR) in vitro. The results revealed that hypoxia significantly altered the levels of nitric oxide and vascular endothelial growth factor, while the cold temperature significantly increased the release of ADR and noradrenaline. Exposure to hypoxia combined with cold temperature significantly affected all these indices. In vitro experiments demonstrated that hypoxia, ADR (which was used to simulate cold in the animal experiments) and the combination of the two factors resulted in damage to the VECs and endothelial dysfunction. In addition, the results also showed that diazoxide, a highly selective mitoKATP opener, protected VECs against these injuries. In conclusion, hypoxia and cold temperature induced endothelial cell dysfunction and endocrine disorders, respectively. Improving endothelial function using diazoxide may be an effective therapeutic strategy in patients with altitude-associated disorders. However, the potential for clinical application requires further study.