Genetic Polymorphisms in Glutathione (GSH-)‎ Related Genes Affect the Plasmatic HgWhole Blood Hg Partitioning and the Distribution between Inorganic and Methylmercury Levels in Plasma Collected from a Fish-Eating Population

Abstract EN

This study aims to evaluate the effects of polymorphisms in glutathione (GSH-) related genes (GSTM1, GSTT1, GSTP1, GCLM, and GCLC) in the distribution of Hg in the blood compartments in humans exposed to methylmercury (MeHg).

Subjects (n=88), exposed to MeHg from fish consumption, were enrolled in the study.

Hg species in the plasma compartment were determined by LC-ICP-MS, whereas genotyping was performed by PCR assays.

Mean total Hg levels in plasma (THgP) and whole blood (THgB) were 10±4.2 and 37±21, whereas mean evels of plasmatic MeHg (MeHgP), inorganic Hg (IHgP), and HgP/HgB were 4.3±2.9, 5.8±2.3 µg/L, and 0.33±0.15, respectively.

GSTM1 and GCLC polymorphisms influence THgP and MeHgP (multivariate analyses, P<0.050).

Null homozygotes for GSTM1 showed higher THgP and MeHgP levels compared to subjects with GSTM1 (THgP β=0.22, P=0.035; MeHgP β=0.30, P=0.050) and persons carrying at least one T allele for GCLC had significant higher MeHgP (β=0.59, P=0.046).

Also, polymorphic GCLM subjects had lower THgP/THgB than those with the nonvariant genotype.

Taken together, data of this study suggest that GSH-related polymorphisms may change the metabolism of MeHg by modifying the distribution of mercury species iin plasma compartment and the HgP/HgB partitioning.