Exposure to Moderate Air Pollution during Late Pregnancy and Cord Blood Cytokine Secretion in Healthy Neonates

Abstract

Background/ObjectivesAmbient air pollution can alter cytokine concentrations as shown in vitro and following short-term exposure to high air pollution levels in vivo. Exposure to pollution during late pregnancy has been shown to affect fetal lymphocytic immunophenotypes. However, effects of prenatal exposure to moderate levels of air pollutants on cytokine regulation in cord blood of healthy infants are unknown.MethodsIn a birth cohort of 265 healthy term-born neonates, we assessed maternal exposure to particles with an aerodynamic diameter of 10 µm or less (PM10), as well as to indoor air pollution during the last trimester, specifically the last 21, 14, 7, 3 and 1 days of pregnancy. As a proxy for traffic-related air pollution, we determined the distance of mothers' homes to major roads. We measured cytokine and chemokine levels (MCP-1, IL-6, IL-10, IL-1ß, TNF-α and GM-CSF) in cord blood serum using LUMINEX technology. Their association with pollution levels was assessed using regression analysis, adjusted for possible confounders.ResultsMean (95%-CI) PM10 exposure for the last 7 days of pregnancy was 18.3 (10.3–38.4 µg/m3). PM10 exposure during the last 3 days of pregnancy was significantly associated with reduced IL-10 and during the last 3 months of pregnancy with increased IL-1ß levels in cord blood after adjustment for relevant confounders. Maternal smoking was associated with reduced IL-6 levels. For the other cytokines no association was found.ConclusionsOur results suggest that even naturally occurring prenatal exposure to moderate amounts of indoor and outdoor air pollution may lead to changes in cord blood cytokine levels in a population based cohort.

The health burden of pollution: the impact of prenatal exposure to air pollutants

“…Maternal smoking was associated with reduced IL-6 levels. There were no relationships involving other IL types in the cord blood 49. Another important aspect of the exposure to pollutants is its relationship with susceptibility to respiratory infections during childhood.…”

Allergy in severe asthma

“…Diesel exhaust particles may also produce other immunological effects (150,151) (Table 2). Furthermore, exposure to moderate air pollution during late pregnancy was found to cause increased cord blood IL-1b (152). A recent meta-analysis, however, showed no clear overall association between air pollution exposure and the development of sensitization in children up to 10 years of age (153).…”

The immune system and developmental programming of brain and behavior

“…While there is debate about whether maternal cytokines cross the placenta, cytokines that are produced directly by the placenta include IL-1, IL-2, IL-6, IL-8, and IL-10, interferons and TNFα, and likely many others [136, 218]. There is a current upsurge in interest into the mechanisms by which placental cytokine expression may impact fetal development; recent evidence suggests an impact on fetal growth via downstream modification of growth factors, such as IGF-1 [136], and leptin [47, 70, 158, 295, 309]. In sum, the placenta has the capacity to produce its own array of cytokines, which can enter the fetal circulation and thereby modulate or interfere with ongoing fetal growth and neurodevelopment [136, 218].…”