Antioxidant intervention attenuates oxidative stress in children and teenagers with Down syndrome.

We previously demonstrated that systemic oxidative stress is present in Down syndrome (DS) patients. In the present study we investigated the antioxidant status in the peripheral blood of DS children and teenagers comparing such status before and after an antioxidant supplementation. Oxidative stress biomarkers were evaluated in the blood of DS patients (n=21) before and after a daily antioxidant intervention (vitamin E 400mg, C 500 mg) during 6 months. Healthy children (n=18) without DS were recruited as control group. The activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), gamma-glutamyltransferase (GGT), glucose-6-phosphate dehydrogenase (G6PD) and myeloperoxidase (MPO), as well as the contents of reduced glutathione (GSH), uric acid, vitamin E, thiobarbituric acid reactive substances (TBARS), and protein carbonyls (PC) were measured. Before the antioxidant therapy, DS patients presented decreased GST activity and GSH depletion; elevated SOD, CAT, GR, GGT and MPO activities; increased uric acid levels; while GPx and G6PD activities as well as vitamin E and TBARS levels were unaltered. After the antioxidant supplementation, SOD, CAT, GPx, GR, GGT and MPO activities were downregulated, while TBARS contents were strongly decreased in DS. Also, the antioxidant therapy did not change G6PD and GST activities as well as uric acid and PC levels, while it significantly increased GSH and vitamin E levels in DS patients. Our results clearly demonstrate that the antioxidant intervention with vitamins E and C attenuated the systemic oxidative damage present in DS patients.

Congenital hypothyroidism alters the oxidative status, enzyme activities and morphological parameters in the hippocampus of developing rats.

Congenital hypothyroidism is associated with delay in cell migration and proliferation in brain tissue, impairment of synapse formation, misregulation of neurotransmitters, hypomyelination and mental retardation. However, the mechanisms underlying the neuropsychological deficits observed in congenital hypothyroidism are not completely understood. In the present study we proposed a mechanism by which hypothyroidism leads to hippocampal neurotoxicity. Congenital hypothyroidism induces c-Jun-N-terminal kinase (JNK) pathway activation leading to hyperphosphorylation of the glial fibrillary acidic protein (GFAP), vimentin and neurofilament subunits from hippocampal astrocytes and neurons, respectively. Moreover, hyperphosphorylation of the cytoskeletal proteins was not reversed by T3 and poorly reversed by T4. In addition, congenital hypothyroidism is associated with downregulation of astrocyte glutamate transporters (GLAST and GLT-1) leading to decreased glutamate uptake and subsequent influx of Ca(2+) through N-methyl-D-aspartate (NMDA) receptors. The Na(+)-coupled (14)C-α-methyl-amino-isobutyric acid ((14)C-MeAIB) accumulation into hippocampal cells also might cause an increase in the intracellular Ca(2+) concentration by opening voltage-dependent calcium channels (VDCC). The excessive influx of Ca(2+) through NMDA receptors and VDCCs might lead to an overload of Ca(2+) within the cells, which set off glutamate excitotoxicity and oxidative stress. The inhibited acetylcholinesterase (AChE) activity might also induce Ca(2+) influx. The inhibited glucose-6-phosphate dehydrogenase (G6PD) and gamma-glutamyl transferase (GGT) activities, associated with altered glutamate and neutral amino acids uptake could somehow affect the GSH turnover, the antioxidant defense system, as well as the glutamate-glutamine cycle. Reduced levels of S100B and glial fibrillary acidic protein (GFAP) take part of the hypothyroid condition, suggesting a compromised astroglial/neuronal neurometabolic coupling which is probably related to the neurotoxic damage in hypothyroid brain.

Avaliação in vivo do efeito hipoglicemiante de extratos obtidos da raiz e folha de bardana Arctium minus (Hill. ) Bernh. / In vivo study of the hypoglycemiant efect of extracts from the root and leaf of the bardana Arctium minus (Hill. ) Bernh

O objetivo do presente estudo foi avaliar in vivo o potencial hipoglicemiante, de extratos obtidos da raiz e folha de bardana, Arctium minus (Asteraceae). Também realizaram-se ensaios farmacognósticos de controle de qualidade. Nos ensaios biológicos, 60 ratos foram induzidos ao diabetes experimental pela administração de aloxano por via endovenosa, na dose única de 42 mg/kg. No sétimo dia após a indução, dosou-se a glicemia de jejum. Os animais com glicemia superior a 190 mg/dL foram redistribuídos em quatro grupos para receberem, por 21 dias, algum tipo de tratamento. Grupo 1: Glibenclamida, na dose de 0,071 mg/kg; Grupo 2: extrato bruto liofilizado da raiz de bardana, 500 mg/kg; Grupo 3: extrato bruto liofilizado da folha de bardana, 200 mg/kg; e Grupo 4: soro fisiológico. Após o tratamento, o extrato bruto da raiz de bardana reduziu em 34,6 ± 5,8 por cento os níveis glicêmicos, o extrato bruto da folha reduziu 22,9 ± 6,2 por cento e a Glibenclamida 34,5 ± 6,2 por cento. O grupo placebo manteve a glicemia. Este estudo demonstrou que o extrato bruto de Arctium minus, principalmente a raiz, é capaz de diminuir os níveis plasmáticos de glicose, com potência semelhante ao medicamento sintético de referência Glibenclamida.

The objective of the present study was to analyze in vivo the hypoglycemiant potential of the extracts from the root and leaf of the medicinal plant bardana, Arctium minus (Asteraceae). It was also carried out through pharmacognostics analysis of quality control. In the biological assays, 60 rats were induced to the experimental diabetes through endovenous injection of alloxan administration, in an only dose of 42 mg/kg. On the seventh day after the induction, the fast glycemia was dosed. The animals with glycemia superior to 190 mg/dL were redistributed in four groups to receive, for 21 days, some kind of treatment. Group 1: Glibenclamide in the dose of 0.071 mg/kg; Group 2: pure lyophilized extract of bardana root, 500 mg/kg; Group 3: pure lyophilized extract of bardana leaf, 200 mg/kg; and Group 4: physiological serum. After treatment, the pure extract of bardana root reduced in 34.6 ± 5.8 percent the glycemic levels, the pure extract of the leaf reduced in 22.9 ± 6.2 percent and the Glibenclamide 34.5 ± 6.2 percent. The placebo group kept the glicemy. This study suggests that the pure extract of Arctium minus, mainly the root extract, is able to reduce the plasmatic levels of glucose, with similar power to the synthetic medicine of Glibenclamide reference.