No correlation was observed between vitamin D levels and disability of patients with multiple sclerosis between latitudes 18° and 30° South / Não foi observada correlação entre os níveis séricos de vitamina D e a incapacidade em pacientes com esclerose múltipla entre as latitudes Sul 18° e 30°

ABSTRACT Objective: Vitamin D has taken center stage in research and treatment of multiple sclerosis (MS). The objective of the present study was to assess the serum vitamin D levels of a large population of patients with MS and controls living in a restricted tropical area. Methods: Data from 535 patients with MS and 350 control subjects were obtained from 14 cities around the Tropic of Capricorn. Results: The mean serum 25-OH vitamin D level was 26.07 ± 10.27 ng/mL for the control subjects, and 28.03 ± 12.19 ng/mL for patients with MS. No correlation was observed between vitamin D levels and the disability of patients over the disease duration. Conclusion: At least for the region around the Tropic of Capricorn, serum levels of vitamin D typically are within the range of 20 to 30 ng/mL for controls and patients with MS.

RESUMO Objetivo: Vitamina D assumiu um papel central na pesquisa e tratamento da esclerose múltipla (EM). O objetivo deste estudo foi avaliar os níveis séricos de vitamina D de pacientes com EM e controles que residem em uma área tropical. Métodos: Foram analisados dados de 535 pacientes com EM e 350 indivíduos controle em 14 cidades próximas ao Trópico de Capricórnio. Resultados: O valor médio da determinação de 25-OH vitamina D foi 26,07 ± 10,27 ng/mL para controles e 28,03 ± 12,19 ng/mL para pacientes com EM. Não houve correlação entre os níveis de vitamina D e o grau de incapacidade ao longo da duração da doença. Conclusão: Pelo menos na região que cerca o Trópico de Capricórnio, os níveis séricos de vitamina D estão entre valores de 20 a 30 ng/mL tanto para controles quanto para pacientes com EM.

A seasonal switch in histone deacetylase gene expression in the hypothalamus and their capacity to modulate nuclear signaling pathways.

Seasonal animals undergo changes in physiology and behavior between summer and winter conditions. These changes are in part driven by a switch in a series of hypothalamic genes under transcriptional control by hormones and, of recent interest, inflammatory factors. Crucial to the control of transcription are histone deacetylases (HDACs), generally acting to repress transcription by local histone modification. Seasonal changes in hypothalamic HDAC transcripts were investigated in photoperiod-sensitive F344 rats by altering the day-length (photoperiod). HDAC4, 6 and 9 were found to change in expression. The potential influence of HDACs on two hypothalamic signaling pathways that regulate transcription, inflammatory and nuclear receptor signaling, was investigated. For inflammatory signaling the focus was on NF-κB because of the novel finding made that its expression is seasonally regulated in the rat hypothalamus. For nuclear receptor signaling it was discovered that expression of retinoic acid receptor beta was regulated seasonally. HDAC modulation of NF-κB-induced pathways was examined in a hypothalamic neuronal cell line and primary hypothalamic tanycytes. HDAC4/5/6 inhibition altered the control of gene expression (Fos, Prkca, Prkcd and Ptp1b) by inducers of NF-κB that activate inflammation. These inhibitors also modified the action of nuclear receptor ligands thyroid hormone and retinoic acid. Thus seasonal changes in HDAC4 and 6 have the potential to epigenetically modify multiple gene regulatory pathways in the hypothalamus that could act to limit inflammatory pathways in the hypothalamus during long-day summer-like conditions.

Expression of the retinoic acid catabolic enzyme CYP26B1 in the human brain to maintain signaling homeostasis.

Retinoic acid (RA) is a potent regulator of gene transcription via its activation of a set of nuclear receptors controlling transcriptional activation. Precise maintenance of where and when RA is generated is essential and achieved by local expression of synthetic and catabolic enzymes. The catabolic enzymes Cyp26a1 and Cyp26b1 have been studied in detail in the embryo, where they limit gradients of RA that form patterns of gene expression, crucial for morphogenesis. This paracrine role of RA has been assumed to occur in most tissues and that the RA synthetic enzymes release RA at a site distant from the catabolic enzymes. In contrast to the embryonic CNS, relatively little is known about RA metabolism in the adult brain. This study investigated the distribution of Cyp26a1 and Cyp26b1 transcripts in the rat brain, identifying several novel regions of expression, including the cerebral cortex for both enzymes and striatum for Cyp26b1. In vivo use of a new and potent inhibitor of the Cyp26 enzymes, ser 2-7, demonstrated a function for endogenous Cyp26 in the brain and that hippocampal RA levels can be raised by ser 2-7, altering the effect of RA on differential patterning of cell proliferation in the hippocampal region of neurogenesis, the subgranular zone. The expression of CYP26A1 and CYP26B1 was also investigated in the adult human brain and colocalization of CYP26A1 and the RA synthetic enzyme RALDH2 indicated a different, autocrine role for RA in human hippocampal neurons. Studies with the SH-SY5Y human neuroblastoma cell line implied that the co-expression of RA synthetic and catabolic enzymes maintains retinoid homeostasis within neurons. This presents a novel view of RA in human neurons as part of an autocrine, intracellular signaling system.

Thyroid hormone activation of retinoic acid synthesis in hypothalamic tanycytes.

Thyroid hormone (TH) is essential for adult brain function and its actions include several key roles in the hypothalamus. Although TH controls gene expression via specific TH receptors of the nuclear receptor class, surprisingly few genes have been demonstrated to be directly regulated by TH in the hypothalamus, or the adult brain as a whole. This study explored the rapid induction by TH of retinaldehyde dehydrogenase 1 (Raldh1), encoding a retinoic acid (RA)-synthesizing enzyme, as a gene specifically expressed in hypothalamic tanycytes, cells that mediate a number of actions of TH in the hypothalamus. The resulting increase in RA may then regulate gene expression via the RA receptors, also of the nuclear receptor class. In vivo exposure of the rat to TH led to a significant and rapid increase in hypothalamic Raldh1 within 4 hours. That this may lead to an in vivo increase in RA is suggested by the later induction by TH of the RA-responsive gene Cyp26b1. To explore the actions of RA in the hypothalamus as a potential mediator of TH control of gene regulation, an ex vivo hypothalamic rat slice culture method was developed in which the Raldh1-expressing tanycytes were maintained. These slice cultures confirmed that TH did not act on genes regulating energy balance but could induce Raldh1. RA has the potential to upregulate expression of genes involved in growth and appetite, Ghrh and Agrp. This regulation is acutely sensitive to epigenetic changes, as has been shown for TH action in vivo. These results indicate that sequential triggering of two nuclear receptor signalling systems has the capability to mediate some of the functions of TH in the hypothalamus.

Patients with multiple sclerosis do not necessarily consume more alcohol or tobacco than the general population / Pacientes com esclerose múltipla não necessariamente consomem mais álcool ou tabaco do que a população geral

Purpose Recent papers suggest that patients with multiple sclerosis (MS) are prone to alcohol misuse. This may be due to the combination of a lifelong and disabling disease with a psychiatric profile typical of MS. The objective of the present study was to assess these findings in a culturally different population of patients with MS.Method The present case-control transversal study assessed 168 patients with MS and 168 control subjects from Brazil.Results There were no evidence that patients with MS drank more alcohol or, smoked more than did controls. In fact, control subjects had a significantly higher alcohol consumption. The only trait associated to higher alcohol consumption was anxiety, both for patients and controls.Conclusion Unlike previous reports in the literature, patients with MS in our study did not drink or smoked more than a control population.

Propósito Artigos recentes sugerem que pacientes com esclerose múltipla (EM) tem tendência ao abuso de álcool. Isto poderia se dever à combinação de uma doença crônica e incapacitante e um perfil psiquiátrico típico da EM. O objetivo do presente estudo foi avaliar estes achados em uma população de pacientes com EM culturalmente diferente.Método O presente estudo caso-controle transversal avaliou 168 pacientes com EM e 168 controles, todos brasileiros.Resultados Não houve evidência que pacientes com EM usassem mais álcool ou tabaco do que os controles. Na verdade, os controles apresentavam um consumo significativamente maior de álcool. O único aspecto associado ao maior consumo de álcool foi a ansiedade, tanto para pacientes quanto para controles.Conclusão Ao contrário de outros dados da literatura, pacientes com EM neste nosso estudo não bebem ou fumam mais do que a população controle.

Patients with multiple sclerosis do not necessarily consume more alcohol or tobacco than the general population.

Purpose Recent papers suggest that patients with multiple sclerosis (MS) are prone to alcohol misuse. This may be due to the combination of a lifelong and disabling disease with a psychiatric profile typical of MS. The objective of the present study was to assess these findings in a culturally different population of patients with MS.Method The present case-control transversal study assessed 168 patients with MS and 168 control subjects from Brazil.Results There were no evidence that patients with MS drank more alcohol or, smoked more than did controls. In fact, control subjects had a significantly higher alcohol consumption. The only trait associated to higher alcohol consumption was anxiety, both for patients and controls.Conclusion Unlike previous reports in the literature, patients with MS in our study did not drink or smoked more than a control population.

Synaptic Ras GTPase activating protein regulates pattern formation in the trigeminal system of mice.

The development of ordered connections or "maps" within the nervous system is a common feature of sensory systems and is crucial for their normal function. NMDA receptors are known to play a key role in the formation of these maps; however, the intracellular signaling pathways that mediate the effects of glutamate are poorly understood. Here, we demonstrate that SynGAP, a synaptic Ras GTPase activating protein, is essential for the anatomical development of whisker-related patterns in the developing somatosensory pathways in rodent forebrain. Mice lacking SynGAP show only partial segregation of barreloids in the thalamus, and thalamocortical axons segregate into rows but do not form whisker-related patches. In cortex, layer 4 cells do not aggregate to form barrels. In Syngap(+/-) animals, barreloids develop normally, and thalamocortical afferents segregate in layer 4, but cell segregation is retarded. SynGAP is not necessary for the development of whisker-related patterns in the brainstem. Immunoelectron microscopy for SynGAP from layer 4 revealed a postsynaptic localization with labeling in developing postsynaptic densities (PSDs). Biochemically, SynGAP associates with the PSD in a PSD-95-independent manner, and Psd-95(-/-) animals develop normal barrels. These data demonstrate an essential role for SynGAP signaling in the activity-dependent development of whisker-related maps selectively in forebrain structures indicating that the intracellular pathways by which NMDA receptor activation mediates map formation differ between brain regions and developmental stage.