Dataset Information

Assessment of Polychlorinated Biphenyls and Their Hydroxylated Metabolites in Postmortem Human Brain Samples: Age and Brain Region Differences.

ABSTRACT: Exposure to polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs) has been implicated in neurodevelopmental disorders. However, the distribution of PCBs and OH-PCBs in the human brain has not been characterized. This study investigated the age-, sex-, and brain region-specific distribution of all 209 PCBs using gaschromatography-tandem mass spectrometry (GC-MS/MS) in neonatal (N = 7) and adult (N = 7) postmortem brain samples. OH-PCB analyses were performed by GC-MS/MS (as methylated derivatives) and, in a subset of samples, by nontarget liquid chromatography high-resolution mass spectrometry (Nt-LCMS). Fourteen higher chlorinated PCB congeners were observed with a detection frequency >50%. Six lower chlorinated PCBs were detected with a detection frequency >10%. Higher chlorinated PCBs were observed with higher levels in samples from adult versus younger donors. PCB congener profiles from adult donors showed more similarities across brain regions and donors than younger donors. We also assess the potential neurotoxicity of the PCB residues in the human brain with neurotoxic equivalency (NEQ) approaches. The median ΣNEQs, calculated for the PCB homologues, were 40-fold higher in older versus younger donors. Importantly, lower chlorinated PCBs made considerable contributions to the neurotoxic potential of PCB residues in some donors. OH-PCBs were identified for the first time in a small number of human brain samples by GC-MS/MS and Nt-LCMS analyses, and all contained four or fewer chlorine.

SUBMITTER: Li X

PROVIDER: S-EPMC9260965 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Hydroxylated metabolites of polychlorinated biphenyls (OH-PCBs) have been found to be ubiquitous in the environment due to the oxidative metabolism of their parent PCBs. With more polarity, OH-PCBs may be more toxic and mobile than their parent compounds. However, the behavior and fate of OH-PCBs have been neglected in the environment because they are not the original contaminants. Some of these hydroxylated metabolites are chiral, and chiral compounds can be used to probe biological metabolic processes. Therefore, chiral OH-PCBs were selected to study their uptake, translocation, transformation, and enantioselectivity in plants in this work. Poplars (Populus deltoides × nigra, DN34), a model plant with complete genomic sequence, were hydroponically exposed to 5-hydroxy-2,2',3,4',6-pentachlorobiphenyl (5-OH-PCB91) and 5-hydroxy-2,2',3,5',6-pentachlorobiphenyl (5-OH-PCB95) for 10 days. Chiral 5-OH-PCB91 and 5-OH-PCB95 were clearly shown to be sorbed, taken up, and translocated in whole poplars, and they were detected in various tissues of whole poplars. However, the enantioselectivity of poplar for 5-OH-PCB91 and 5-OH-PCB95 proved to be quite different. The second-eluting enantiomer of OH-PCB95, separated on a chiral column (Phenomenex Lux Cellulose-1), was enantioselectively removed in whole poplar. Enantiomeric fractions in the middle xylem, top bark, top xylem, and stem, reached 0.803 ± 0.022, 0.643 ± 0.110, 0.835 ± 0.087, and 0.830 ± 0.029, respectively. Therefore, 5-OH-PCB95 was significantly enantioselectively biotransformed inside poplar tissues, in contrast to nearly racemic mixtures of 5-OH-PCB95 remaining in hydroponic solutions. Unlike 5-OH-PCB95, 5-OH-PCB91 remained nearly racemic in most tissues of whole poplars during 10 day exposure, suggesting the enantiomers of 5-OH-PCB91 were equally transported and metabolized in whole poplars. This is the first evidence of enantioselectivity of chiral OH-PCBs and suggests that poplars can enantioselectively biotransform at least one chiral OH-PCB: namely, 5-OH-PCB95.

Dataset Information

Assessment of Polychlorinated Biphenyls and Their Hydroxylated Metabolites in Postmortem Human Brain Samples: Age and Brain Region Differences.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets