The relationship between lead in plasma and whole blood in women.

Abstract

Studies have suggested that plasma lead levels may better reflect the toxicologically labile fraction of circulatory Pb that is more freely available for exchange with target tissues than do Pb levels in whole blood. Studies have also reported an apparent severalfold variation in the relative partitioning of Pb between whole blood and plasma (or serum) for a given whole-blood Pb level. This may reflect inherent differences in the plasma Pb/whole blood Pb partitioning among individuals and/or methodologic challenges associated with the collection and analyses of samples that generally contain < 1-2 ng total Pb. Here, we conducted a longitudinal assessment of the relationship between Pb in whole blood and plasma in environmentally exposed reproductive-age women (n = 63) living in Mexico City, Mexico. We collected whole blood and plasma samples using trace metal clean techniques and analyzed them for Pb using high-resolution inductively coupled plasma mass spectrometry. A subset of subjects provided repeated blood samples weekly for 4 consecutive weeks (n = 17 subjects) or every 1-2 months over a 9-month period (n = 14 subjects). Plasma Pb concentration was significantly positively associated with whole-blood Pb in a curvilinear fashion over the range of blood Pb values observed here (2.13-39.7 microg/dL). This relationship was best described by the function Plasma Pb = e (-2.392 + 0.0898 x blood Pb), where SE(coefficient) = 0.0054, SE(constant) = 0.063 (n = 63 subjects, n = 141 observations). Results from the short- and long-term repeated collection subjects indicated that the within- and between-subject variance components were not significantly different between the two subsets of subjects. The between-subjects component accounts for 78% of the variance in plasma Pb levels, while the residual variance (22%) may be attributed to other unmeasured factors. Collectively, this study demonstrates that plasma Pb measurements may be applied to general clinical settings, provided that established trace metal clean techniques are adopted. This study also shows that the relative (%) partitioning of whole-blood Pb in plasma naturally varies by a factor of about 2-4-fold among subjects at a given blood Pb level. Because Pb in the plasma is considered to more closely represent the fraction of Pb in the circulation that is readily exchanged with peripheral target tissues (e.g., brain, kidney, skeleton), the routine assessment of plasma Pb may provide a more meaningful measure of toxicologically available Pb.

Biological Monitoring Among Workers Exposed to Inorganic Lead and Its Compounds

“…Therefore, there is renewed and increased interest in alternative biomarkers that could facilitate better diagnosis and understanding of the lead exposure extent. Such alternatives include lead determinations in plasma/serum, saliva, bone, teeth, feces, and urine [26].…”

Characterizing Golden Eagle Risk to Lead and Anticoagulant Rodenticide Exposure: A Review

“…An additional study from the same groups of investigators reported that birth length of newborns decreased as maternal patella lead increased, and also that patella lead was significantly related to the risk of a low head circumference score (Hernandez-Avila et al 2002). In the Mexico City Prospective Study, an increase in PbB at 12 months of age from 6 to 12.5 μg/dL was associated with a decrease in head circumference of 0.34 cm (Rothenberg et al 1999c).…”

“…Lead in blood is primarily in the red blood cells (99%) (Bergdahl et al 1997a(Bergdahl et al , 1998(Bergdahl et al , 1999Hernandez-Avila et al 1998;Manton et al 2001;Schutz et al 1996;Smith et al 2002). Most of the lead found in red blood cells is bound to proteins within the cell rather than the erythrocyte membrane.…”

“…The technique has been applied to assessing lead exposures in adults (Cake et al 1996;Hernandez-Avila et al 1998;Manton et al 2001;Smith et al 2002;Tellez-Rojo et al 2004). A direct comparison of lead concentrations in plasma and serum yielded similar results (Bergdahl et al 2006); however, the interchangeability of plasma and serum lead measurements for biomonitoring of lead exposure or body burden had not been thoroughly evaluated in large numbers of subjects (Bergdahl et al 2006;Manton et al 2001;Smith et al 2002).…”

A importância da análise de especiação do chumbo em plasma para a avaliação dos riscos à saúde

“…Provavelmente, esta última fração é o centro metabolicamente ativo do depósito de chumbo no organismo e fornece a melhor aproximação do conteúdo de chumbo biologicamente efetivo 13 . Porém, a variação natural na partição relativa (%) do chumbo entre sangue total e plasma é de 2 a 4 vezes para um determinado nível deste elemento no sangue total e reflete as diferenças inerentes aos indivíduos, contanto que técnicas limpas e sensíveis sejam usadas para coleta e análise das amostras, respectivamente 65 . As baixas concentrações de chumbo no plasma fazem com que estas medidas sejam extremamente difíceis, particularmente em baixas concentrações de Pb-S (menos de 20 µg dL -1 ).…”