High-frequency repetitive magnetic stimulation rescues ischemia-injured neurons through modulation of glial-derived neurotrophic factor present in the astrocyte's secretome.

Due to its ability to improve the most frequent clinical sequelae left by ischemia, repetitive transcranial magnetic stimulation has been considered a promising therapeutic strategy for stroke. Those improvements are associated with changes in neurons and their synaptic liaisons. However, the hypothesis that this technique modulates astrocytes, potentiating their neuroprotective capabilities, was also raised. This study aims to identify the effects triggered by high-frequency repetitive magnetic stimulation (HF-rMS) on astrocytes that contribute to its neuroprotective effects. Neuron-glia and astrocyte cortical cultures subject to oxygen and glucose deprivation were used as an in vitro model of ischemia. Neuroprotection promoted by HF-rMS was evaluated by analysis of markers of neuronal activity and morphometric analysis of neurons. Glial reactivity was determined by immunocytochemistry. The levels of growth factors in the astrocyte-conditioned medium (CM) were assessed through a Growth Factor Array and glial-derived neurotrophic factor (GDNF) expression was analyzed by RT-PCR and Western blot. Our results show that neurons injured by ischemia can be rescued through the modulation of astrocytes by HF-rMS. This modulation helps to maintain the number and length of neurites and increases the number of neurons expressing ERK1/2 and c-Fos. Analysis of the astrocyte-CM showed that HF-rMS stimulated the release of several trophic factors by astrocytes. Moreover, GDNF was one of the released factors that contributed to the recovery mechanisms triggered by HF-rMS. Our results show that modulation of astrocytes by HF-rMS effectively rescues neurons injured by ischemia and suggest that by targeting astrocytes this approach can also be used to promote neuroprotection in other brain lesions.

Sulfite concentration and the occurrence of headache in young adults: a prospective study.

BACKGROUND/OBJECTIVES: Sulfites are additives commonly used in food and wine industries that are associated to adverse clinical effects such as headaches. The objective of this study is to investigate the possible association between sulfite concentration in wine and the occurrence of headaches in young adults. SUBJECTS/METHODS: Eighty volunteers, aged between 18 and 25 years, were evaluated. Sub-groups (with or without previous headaches related with wine) were created and volunteers were submitted to two wine tests (minimum and maximum sulfite concentration accordingly to weight). A questionnaire was handed out after the test regarding the presence or not of headaches, their main characteristics, as well as other symptoms associated. RESULTS: Subjects that refer a previous headache history upon wine ingestion presented a risk 2266 greater of developing headaches after wine ingestion with a greater sulfite concentration. Those that refer constant headaches related to wine ingestion previous to the test present a risk of 6232 times more of developing headaches compared to those who refer sporadic headaches related to wine consumption. CONCLUSIONS: In our group of subjects, sulfite concentration in wine is related to the risk of developing headaches in individuals who are susceptible to wine induced headaches.