Pregnancy increases mobilization of lead from maternal skeleton
Pregnancy increases mobilization of lead from maternal skeleton
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DOI：
10.1016/s0022-2143(97)90058-5
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发表时间：
1997-07-01
期刊：
影响因子：
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通讯作者：
Vimpani, G
中科院分区：
文献类型：
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作者：
Gulson, BL;Jameson, CW;Vimpani, G
在怀孕和哺乳期间，母体骨骼中铅的动员程度问题是铅毒性最突出的问题之一。我们进行了一项纵向队列研究，在城市环境中的欧洲女性移民的育龄期（18至35岁），澳大利亚的骨骼铅同位素组成已被确定为不同的，在他们目前的环境。该队列由100名移民组成，预计将提供20名妊娠受试者，并将其与两组对照受试者进行比较：匹配的移民非妊娠对照组和第二代澳大利亚妊娠对照组。怀孕的受试者也作为自己的对照，比较怀孕期间的变化与怀孕前的变化。高精度的铅同位素组成和铅浓度测量母体血液和尿液产前，每月在怀孕期间，和产后6个月;他们也测量婴儿血液和尿液6个月;环境措施采样每季度6天重复饮食，房屋灰尘和水，城市空气和汽油。由于对铅暴露的持续公共卫生关注，正在报告该队列的中期结果。到目前为止，移民受试者中有13例受孕，7例分娩，此外，澳大利亚对照组中有3例受孕，2例分娩。铅含量普遍较低，几何平均值为3.0微克/分升，范围为1.9至20微克/分升。即使在血铅水平较低的受试者中，也可检测到妊娠期间PbB增加约20%。基于同位素测量，骨骼对血铅水平的贡献显示出平均增加（和标准差）31% +/- 19%，范围为9%至65%。早期仅使用铅浓度的研究表明，血铅水平仅在怀孕后半期增加。在本研究中也观察到血铅水平的增加。然而，在两名受试者中，在怀孕的前2个月也检测到总血铅的增加。澳大利亚孕妇对照组在妊娠期间同位素组成和血铅的变化可以忽略不计。脐带血/母血铅水平的比值为0.54 ~ 1.05，同位素组成的比值为0.993 ~ 1.002。这项研究的结果证实，铅是动员从骨骼商店在怀孕期间加速，并转移到胎儿。这些结果还表明，从长期储存（即，骨）在怀孕期间对血铅水平有很大影响。此外，胎儿在怀孕期间暴露于铅对解释仅归因于产后暴露的神经行为障碍具有影响。即使在澳大利亚居住800天后，欧洲骨骼铅对未怀孕受试者血铅的贡献可能约为50%，但目前的PbB可能没有表明以前的高骨骼铅负荷。
The question of the extent of lead mobilization from the maternal skeleton during pregnancy and lactation is one of the most outstanding problems of lead toxicity. We have undertaken a longitudinal cohort study in an urban environment of European female immigrants of child-bearing age (18 to 35 years) to Australia whose skeletal lead isotopic composition has been determined to be different from that in their current environment. The cohort was to consist of 100 immigrants anticipated to provide 20 pregnant subjects who would be compared with two groups of control subjects: a matched immigrant nonpregnant control group and second-generation Australian pregnant control subjects. Pregnant subjects also serve as their own controls for a comparison of changes during gestation with those before conception. High-precision lead isotopic compositions and lead concentrations are measured in maternal blood and urine prenatally, monthly during gestation, and post-natally for 6 months; they are also measured in infant blood and urine for 6 months; environmental measures are sampled quarterly for 6-day duplicate diet, house dust and water, and urban air and gasoline. Because of continuing public health concerns about lead exposure; interim findings from this cohort are being reported. To date there have been 13 conceptions in immigrant subjects, with 7 births, in addition to 3 conceptions in the Australian control group, with 2 births. PbBs have been generally low, with a geometric mean of 3.0 mu g/dl, and have ranged from 1.9 to 20 mu g/dl. Increases in PbB of similar to 20% during pregnancy have been detectable even in subjects with low blood lead levels, The skeletal contribution to blood lead level, based on isotopic measurements, has exhibited a mean increase (and standard deviation) of 31% +/- 19% with a range from 9% to 65%. Earlier studies that used lead concentrations only have suggested that blood lead levels increased only during the second half of pregnancy. This increase in blood lead levels has also been observed in the present study. However, in two subjects the increases in total blood lead were also detected in the first 2 months of pregnancy. Changes in isotopic composition and blood lead during gestation for Australian pregnant controls were negligible. The ratio of cord/maternal blood lead levels varied from 0.54 to 1.05, and the ratio for the isotopic composition was 0.993 to 1.002. Results of this study confirm that lead is mobilized from skeletal stores at an accelerated rate during pregnancy and is transferred to the fetus. These results also show that mobilization from longterm stores (i.e., bone) contributes significantly to blood lead levels during pregnancy. Furthermore, exposure of the fetus to lead during pregnancy has implications for interpretations of neurobehavioral disorders attributed to only postnatal exposure. Even after 800 days of residence in Australia, the contribution of European skeletal lead to blood lead in nonpregnant subjects can be on the order of 50%, but the current PbB may give no indication of the former high skeletal lead burden.