Park Ju-Hyeong, Szponar Bogumila, Larsson Lennart, Gold Diane R, Milton Donald K
Division of Respiratory Disease Studies, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA.
Appl Environ Microbiol. 2004 Jan;70(1):262-7. doi: 10.1128/AEM.70.1.262-267.2004.
The 3-hydroxy fatty acids (3-OHFAs) in lipopolysaccharides (LPS) play an important role in determining endotoxin activity, and childhood exposure to endotoxin has recently been associated with reduced risk of atopic diseases. To characterize the 3-OHFAs in house dust (HD), we used gas chromatography-mass spectrometry to assay 190 HD samples. Dust from beds, bedroom floors, family rooms, and kitchen floors was collected as part of a birth cohort study of childhood asthma (study 1) and a longitudinal study of home allergen and endotoxin (study 2). We also measured endotoxin activity with a Limulus assay and computed specific activity (endotoxin activity per nanomole of LPS). Longer-chain (C(16:0) and C(18:0)) 3-OHFAs were predominant in HD compared with short-chain (C(10:0), C(12:0), and C(14:0)) acids. Endotoxin activity was positively correlated with short-chain 3-OHFAs in both studies. In study 2, 3-OH C(16:0) was negatively correlated and 3-OH C(18:0) was not correlated with endotoxin activity, consistent with previous findings that the Limulus assay responds preferentially to LPS containing short-chain 3-OHFAs. Kitchen dust contained the highest concentrations of 3-OH C(10:0), the highest endotoxin activities, and the highest specific activities (P < 0.03). Bed dust contained the largest amounts of long-chain 3-OHFAs, the highest concentrations of LPS, and the lowest specific activities. Apartments had significantly different types of LPS (P = 0.03) compared with single-family homes in study 2. These data suggest that the Limulus assay may underestimate exposure to certain types of LPS. Because nontoxic LPS may have immune modulating effects, analysis of 3-OHFAs may be useful in epidemiologic studies.
脂多糖（LPS）中的3-羟基脂肪酸（3-OHFAs）在决定内毒素活性方面起着重要作用，并且儿童时期接触内毒素最近被认为与特应性疾病风险降低有关。为了表征室内灰尘（HD）中的3-OHFAs，我们使用气相色谱-质谱法分析了190份HD样本。作为儿童哮喘出生队列研究（研究1）以及家庭过敏原和内毒素纵向研究（研究2）的一部分，收集了来自床铺、卧室地板、家庭活动室和厨房地板的灰尘。我们还使用鲎试剂法测量内毒素活性，并计算比活性（每纳摩尔LPS的内毒素活性）。与短链（C(10:0)、C(12:0)和C(14:0)）酸相比，长链（C(16:0)和C(18:0)）3-OHFAs在HD中占主导地位。在两项研究中，内毒素活性均与短链3-OHFAs呈正相关。在研究2中，3-OH C(16:0)与内毒素活性呈负相关，而3-OH C(18:0)与内毒素活性不相关，这与之前的研究结果一致，即鲎试剂法优先对含有短链3-OHFAs的LPS产生反应。厨房灰尘中3-OH C(10:0)的浓度最高，内毒素活性最高，比活性也最高（P < 0.03）。床铺灰尘中长链3-OHFAs的含量最高，LPS浓度最高，比活性最低。在研究2中，公寓与独栋住宅相比，LPS的类型存在显著差异（P = 0.03）。这些数据表明，鲎试剂法可能会低估对某些类型LPS的暴露。由于无毒LPS可能具有免疫调节作用，因此对3-OHFAs的分析在流行病学研究中可能有用。
