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Critical aspects of the physiological interactions between lead and magnesium.
Wyparło-Wszelaki, M, Machoń-Grecka, A, Wąsik, M, Dobrakowski, M
Journal of biochemical and molecular toxicology. 2022;(2):e22964
Abstract
Despite technological progress, exposure to lead is an ongoing problem. There are many mechanisms governing the toxic effects of lead on the human body. One such mechanism involves the interaction of this xenobiotic with bivalent metal ions, including magnesium. Literature data suggest that the competition between these elements for binding sites at the molecular and cellular levels, as well as at the systemic level, may represent an important aspect of lead toxicity in the human body. This is especially clear in the context of oxidative stress, immune response, and gene expression modifications. This review aims to summarize current knowledge regarding these issues.
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Association between inflammatory marker, environmental lead exposure, and glutathione S-transferase gene.
Sirivarasai, J, Wananukul, W, Kaojarern, S, Chanprasertyothin, S, Thongmung, N, Ratanachaiwong, W, Sura, T, Sritara, P
BioMed research international. 2013;:474963
Abstract
A number of studies suggested that lead is related to the induction of oxidative stress, and alteration of immune response. In addition, modifying these toxic effects varied partly by GST polymorphism. The objectives of this study were to assess the association between the lead-induced alteration in serum hs-CRP, with GSTM1, GSTT1, and GSTP1 Val105Ile genetic variations and the health consequence from environmental lead exposure. The 924 blood samples were analyzed for blood lead, CRP, and genotyping of three genes with real-time PCR. Means of blood lead and serum hs-CRP were 5.45 μ g/dL and 2.07 mg/L. Both CRP and systolic blood pressure levels were significantly higher for individuals with blood lead in quartile 4 (6.48-24.63 μ g/dL) compared with those in quartile 1 (1.23-3.47 μ g/dL, P < 0.01). In particular, in men with blood lead >6.47 μ g/dL the adjusted odds ratio (OR) of CRP levels for individuals with GSTP1 variants allele, GSTM1 null, GSTT1 null, double-null GSTM1, and GSTT1 compared with wild-type allele was 1.46 (95% CI; 1.05-2.20), 1.32 (95% CI; 1.03-1.69), 1.65 (95% CI; 1.17-2.35), and 1.98 (95% CI; 1.47-2.55), respectively. Our findings suggested that lead exposure is associated with adverse changes in inflammatory marker and SBP. GST polymorphisms are among the genetic determinants related to lead-induced inflammatory response.
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3.
Biomonitoring of a population of Portuguese workers exposed to lead.
García-Lestón, J, Roma-Torres, J, Vilares, M, Pinto, R, Cunha, LM, Prista, J, Teixeira, JP, Mayan, O, Pásaro, E, Méndez, J, et al
Mutation research. 2011;(1):81-8
Abstract
Lead is a heavy metal that has been used for many centuries and it is still used for various industrial purposes thanks to its physical and chemical characteristics. Human exposure to lead can result in a wide range of biological effects depending upon the level and duration of exposure. Despite the fact that lead has been found capable of eliciting genotoxic responses in a wide range of tests, not all studies have been conclusive. Although several experimental studies have shown that lead may modulate immune responses, data in exposed humans are still preliminary. The purpose of our study was to evaluate the genotoxic and immunotoxic effects of lead exposure in a group of 70 male workers from two Portuguese factories. The control group comprised 38 healthy males. The exposed individuals showed significantly higher levels of lead in blood and zinc protoporphyrin, and significantly lower δ-aminolevulinic acid dehydratase activity than the controls, suggesting a relatively high lead exposure. Nevertheless, the limit of 70 μg/dl for lead in blood established by the Portuguese regulation was never reached. Results of the comet assay were not modified by the exposure, but a significant increase in the mutation frequency in the exposed workers was obtained in the T-cell receptor mutation assay. Furthermore, data obtained in the analysis of the different lymphocyte subsets showed a significant decrease in %CD8+ cells and a significant increase in the %CD4+/%CD8+ ratio in exposed individuals with regard to the controls. No clear effect was observed for vitamin D receptor genetic polymorphism on the parameters evaluated. In view of our results showing mutagenic and immunotoxic effects related to lead exposure in occupational settings, it seems that the Portuguese biological exposure limit for lead needs to be revised in order to increase the safety of exposed workers.
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4.
[The impact of lead and cadmium on the immune system].
Skoczyńska, A, Poreba, R, Sieradzki, A, Andrzejak, R, Sieradzka, U
Medycyna pracy. 2002;(3):259-64
Abstract
A long-lasting exposure to lead and cadmium may cause changes in the immune response. Until now only a few reports have addressed this problem. At present, the direct immunotoxicity of heavy metals is the subject of extensive studies, especially on in vitro models. Heavy metals may regulate the immune response of the body at its different stages, modifying early and late inflammatory reactions, among others through changing the number of circulating B and T lymphocytes, NK cells and immunological memory cells. Some authors show that lead and cadmium stimulate the production of cytokines and IgE antibodies, which can be the reason for the increased number of atopic diseases in populations exposed to these two metals. Clinical tests in patients occupationally exposed to lead revealed the diminished number of B and T lymphocytes, and a considerable decrease in the number of NK cells. Other authors noted the increased number of CD8+ lymphocytes, which play a pivotal role in cytotoxic response, and the decreased number of B lymphocytes together with the increased IgA levels in policemen of road services. In copper smelters some changes in humoral response can be detected, e.g. a lower production of IgA and IgG, predisposing them to infections and cancers. To elucidate the exact impact of heavy metals on the immunological response further investigations are required. The growing pollution of the environment by heavy metals probably contributes to the enhanced incidence of allergic diseases and cancers in urban populations. Our goal should be to identify the mechanisms responsible for the changes in the immunological response induced by lead and cadmium, so that it could be possible to reduce or minimize serious pathologies resulting from the exposure to these metals.