住宅灰尘中的内毒素与哮喘发作相关

 
 
根据全国性采集样本的研究发现，暴露于灰尘中的内毒素是哮喘的一个危险因素。研究人员从5个不同地区室内采集的2,552个家庭灰尘样本，包括卧室地板、被褥、家庭房间地板、沙发表面和厨房地板。

作者发现在哮喘、哮喘药物和喘息与卧室地板和被褥灰尘水平之间存在强烈的相关性。尽管内毒素浓度在厨房和起居室地板灰尘中最高，而在被褥中最低(包括床垫和枕头)。但是这些效应只在成人中观察到，而在儿童中则没有观察到。

没有观察到过敏状态对内毒素和哮喘预后之间关系有何影响。这就提示当前的内毒素暴露对过敏状态影响很小，而气管炎症对内毒素暴露横断面人群影响最为显著。这项研究发表在2005年12月第一期的《美国呼吸和重症监护医学》之上。

内毒素是特定革兰氏阴性细菌外膜的毒性物质。这些分子与细菌细胞壁相结合，当细菌破裂或者分裂的时候释放出来。

Endotoxins in House Dust Linked to Asthma
 
Exposure to household endotoxins in dust poses a significant risk for asthma, according to the first nationwide sampling of house dust. The investigators took 2,552 house dust samples from five locations within the home, including bedroom floors, bedding, family room floors, sofa surfaces, and kitchen floors.

The authors found that the strongest relationship between asthma, asthma medications, and wheezing came from endotoxin levels in bedroom floor and bedding dust. This was true despite the fact that endotoxin concentrations were highest in kitchen and living room floor dust, and lowest for bedding (including mattress and pillow). However, the effects were observed only in adults and not in children.

No effect was observed of allergy status on the relationship between endotoxin and asthma outcomes. This suggests that current endotoxin exposure may have little impact on allergy status and that airway inflammation is the most significant effect of endotoxin exposure in a cross-section of the population. The study appeared in the first issue for December 2005 of the American Journal of Respiratory and Critical Care Medicine.

Endotoxins are toxic substances associated with the outer membrane of certain Gram-negative bacteria. These molecules are bound to the bacterial cell wall and are released when the bacterium ruptures or disintegrates.