Produção excessiva de proteínas explica osteoporose relacionada ao tabagismo

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July 30, 2012 – 6:54 pm

Fonte: R7

Cerca de duas décadas após cientistas identificarem o tabagismo como fator de risco para osteoporose e fraturas ósseas, um novo estudo lança luz sobre o processo desencadeado pelo fumo que é responsável pelo enfraquecimento dos ossos. O relatório publicado no ACS Journal of Proteome Research conclui que a fumaça do cigarro desencadeia a produção excessiva de duas proteínas que aceleram processo natural de reabsorção óssea do corpo .

O pesquisador envolvido no projeto Gary Guishan Xiao, da Creighton University, nos Estados Unidos, observa que estudos anteriores sugerem que toxinas presentes na fumaça do cigarro afetam a atividade dos osteoblastos – células responsáveis por construir novos ossos – e dos osteoclastos – células que reabsorvem, ou quebram os ossos velhos.

O presente estudo reúne evidências de que fumantes produzem quantidades anormalmente elevadas das proteínas S100A8 e S100A9 , que aceleram a produção dos osteoclastos. Resultados sugerem que a perda óssea relacionada ao tabagismo está ligada ao aumento da reabsorção óssea.

Descoberta foi realizada por meio da análise das diferenças da atividade genética em células de medula óssea de fumantes e não fumantes. Experimentos com ratos de laboratório confirmaram a descoberta.

 

Vitamina D e Tabagismo. Vitamin D may protect against lung function impairment and decline in smokers

Sobre Vitamina D, assista ao vídeo do Programa Sem Censura:

 Vitamina D – Sem Censura – Dr. Cicero Galli Coimbra e Daniel Cunha

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July 20, 2012 in Health

pulmões de fumante e não fumante

pulmões de fumante e não fumante

Vitamin D deficiency is associated with worse lung function and more rapid decline in lung function over time in smokers, suggesting that vitamin D may have a protective effect against the effects of smoking on lung function, according to a new study from researchers in Boston.

“We examined the relationship between vitamin D deficiency, smoking, lung function, and the rate of lung function decline over a 20 year period in a cohort of 626 adult white men from the Normative Aging Study,” said lead author Nancy E. Lange, MD, MPH, of the Channing Laboratory, Brigham and Women’s Hospital. “We found that vitamin D sufficiency (defined as serum vitamin D levels of >20 ng/ml) had a protective effect on lung function and the rate of lung function decline in smokers.”

The findings were published online ahead of print publication in the American Thoracic Society‘s American Journal of Respiratory and Critical Care Medicine.

In the study, vitamin D levels were assessed at three different time points between 1984 and 2003, and lung function was assessed concurrently with spirometry.

In vitamin D deficient subjects, for each one unit increase in pack-years of smoking, mean forced expiratory volume in one second (FEV1) was 12 ml lower, compared with a mean reduction of 6.5 ml among subjects who were not vitamin D deficient. In longitudinal models, vitamin D deficiency exacerbated the effect of pack years of smoking on the decline in FEV1 over time.

No significant effect of vitamin D levels on lung function or lung function decline were observed in the overall study cohort, which included both smokers and non-smokers.

“Our results suggest that vitamin D might modify the damaging effects of smoking on lung function,” said Dr. Lange. “These effects might be due to vitamin D’s anti-inflammatory and anti-oxidant properties.”

The study has some limitations, including that the data is observational only and not a trial, that vitamin D levels fluctuate over time, and that the study has limited generalizability due to the cohort being all elderly men.

“If these results can be replicated in other studies, they could be of great public health importance,” said Dr. Lange. “Future research should also examine whether vitamin D protects against lung damage from other sources, such as air pollution.”

“While these results are intriguing, the health hazards associated with smoking far outweigh any protective effect that vitamin D may have on lung function ,” said Alexander C. White MS, MD, chair of the American Thoracic Society’s Tobacco Action Committee. “First and foremost, patients who smoke should be fully informed about the health consequences of smoking and in addition be given all possible assistance to help them quit smoking.”

Journal reference: American Journal of Respiratory and Critical Care Medicine

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Asma e Vitamina D – Vitamin D deficiency and poorer lung function in asthmatic children treated with steroids

Asthma in America

Asthma in America (Photo credit: GDS Infographics)

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Assista à entrevista sobre este assunto, em português:

Vitamina D – Sem Censura – Dr. Cicero Galli Coimbra e Daniel Cunha

Ao vídeo:

Vitamina D – Por uma outra terapia (Vitamin D – For an alternative therapy)

Leia:

Vitamina D pode revolucionar o tratamento da esclerose múltipla

 

 

Vitamin D deficiency is associated with poorer lung function in asthmatic children treated with inhaled corticosteroids, according to a new study from researchers in Boston.

“In our study of 1,024 children with mild to moderate persistent asthma, those who were deficient in vitamin D levels showed less improvement in pre-bronchodilator forced expiratory volume in 1 second (FEV1) after one year of treatment with inhaled corticosteroids than children with sufficient levels of vitamin D,” said Ann Chen Wu, MD, MPH, assistant professor in the Department of Population Medicine at Harvard Medical School and Harvard Pilgrim Health Care Institute. “These results indicate that vitamin D supplementation may enhance the anti-inflammatory properties of corticosteroids in patients with asthma.”

The findings were published online ahead of print publication in the American Thoracic Society‘s American Journal of Respiratory and Critical Care Medicine.

The study was conducted using data from the Childhood Asthma Management Program, a multi-center trial of asthmatic children between the ages of five and 12 years who were randomly assigned to treatment with budesonide (inhaled corticosteroid), nedocromil, or placebo. Vitamin D levels were categorized as deficient (≤ 20 ng/ml), insufficient (20-30 ng/ml), or sufficient (> 30 ng/ml).

Among children treated with inhaled corticosteroids, pre-bronchodilator FEV1 increased during 12 months of treatment by 330 ml in the vitamin D insufficiency group and 290 ml in the vitamin D sufficiency group, but only 140 ml in the vitamin D deficient group.

Compared with children who were vitamin D sufficient or insufficient, children who were vitamin D deficient were more likely to be older, be African American, and have higher BMI. Compared with being vitamin D deficient, being vitamin D sufficient or insufficient was associated with a greater change in pre-bronchodilator FEV1 over 12 months of treatment after adjustment for age, gender, race, BMI, history of emergency department visits, and season that the vitamin D specimen was drawn.

The study had some limitations, including a small sample size of 101 vitamin D deficient children, and the investigators only studied vitamin D levels at one time point.

“Our study is the first to suggest that vitamin D sufficiency in asthmatic children treated with inhaled corticosteroids is associated with improved lung function,” said Dr. Wu. “Accordingly, vitamin D levels should be monitored in patients with persistent asthma being treated with inhaled corticosteroids. If vitamin D levels are low, supplementation with vitamin D should be considered.”
Source: American Thoracic Society

http://www.sciencecodex.com/vitamin_d_deficiency_and_poorer_lung_function_in_asthmatic_children_treated_with_steroids-94927

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