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In utero arsenic exposure is associated with impaired thymic function in newborns possibly via oxidative stress and

Sultan Ahmed1, Khalid Bin Ahsan, Maria Kippler

  • 1Institute of Environmental Medicine, Karolinska Institutet, 17177 Stockholm, Sweden.

Toxicological Sciences : an Official Journal of the Society of Toxicology
|June 21, 2012
PubMed

Insights

Prenatal arsenic exposure harms infant immune development by reducing thymus function. This study in Bangladesh found arsenic exposure linked to lower T-cell receptor excision circles (TRECs), indicating impaired thymic activity and potential childhood immunosuppression.

Area of Science:

  • Environmental Health
  • Immunotoxicology
  • Developmental Pediatrics

Background:

  • Prenatal exposure to arsenic is linked to infant morbidity and reduced thymus size, suggesting developmental immunotoxicity.
  • The thymus is crucial for T-cell maturation and immune system development.
  • Understanding the impact of environmental toxins on fetal immune development is critical for public health.

Purpose of the Study:

  • To evaluate the effects of prenatal arsenic exposure on thymic function at birth.
  • To investigate the underlying mechanisms, including oxidative stress and apoptosis, linking arsenic exposure to immune dysfunction.

Main Methods:

  • A cohort study in Bangladesh measured arsenic levels in maternal urine and blood during pregnancy.
  • Infant thymic index was assessed by sonography at birth, and thymic function was measured by signal-joint T-cell receptor-rearrangement excision circles (sjTRECs) in cord blood.
  • Gene expression, arsenic concentrations in placenta/cord blood, and oxidative stress markers were analyzed in a subsample.

Main Results:

  • Higher prenatal arsenic exposure (urine and blood) was inversely associated with sjTRECs in cord blood mononuclear cells (CBMC), indicating reduced thymic function.
  • These associations were also observed in isolated CD4(+) and CD8(+) T cells.
  • Arsenic exposure was positively associated with 8-hydroxy-2'-deoxyguanosine in cord blood, a marker of oxidative stress, which was inversely linked to sjTRECs.

Conclusions:

  • Prenatal arsenic exposure is associated with impaired thymic function at birth in a Bangladeshi cohort.
  • The findings suggest that arsenic may induce thymic dysfunction through oxidative stress and apoptosis.
  • This prenatal immunotoxicity could lead to increased susceptibility to infections and immune-related diseases in childhood.

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