Elevated plasma endothelin-1 and pulmonary arterial pressure in children exposed to air pollution

BACKGROUND: Controlled exposures of animals and humans to particulate matter (PM) or ozone air pollution cause an increase in plasma levels of endothelin-1, a potent vasoconstrictor that regulates pulmonary arterial pressure. OBJECTIVES: The primary objective of this field study was to determine whether Mexico City children, who are chronically exposed to levels of PM and [O.sub.3] that exceed the United States air quality standards, have elevated plasma endothelin-1 levels and pulmonary arterial pressures. METHODS: We conducted a study of 81 children, 7.9 [+ or -] 1.3 years of age, lifelong residents of either northeast (n = 19) or southwest (n = 40) Mexico City or Polotitlan (n = 22), a control city with PM and [O.sub.3] levels below the U.S. air quality standards. Clinical histories, physical examinations, and complete blood counts were done. Plasma endothelin-1 concentrations were determined by immunoassay, and pulmonary arterial pressures were measured by Doppler echocardiography. RESULTS: Mexico City children had higher plasma endothelin-1 concentrations compared with controls (p < 0.001). Mean pulmonary arterial pressure was elevated in children from both northeast (p < 0.001) and southwest (p < 0.05) Mexico City compared with controls. Endothelin-1 levels in Mexico City children were positively correlated with daily outdoor hours (p = 0.012), and 7-day cumulative levels of PM air pollution < 2.5 [micro]m in aerodynamic diameter ([PM.sub.2.5]) before endothelin1 measurement (p = 0.03). CONCLUSIONS: Chronic exposure of children to [PM.sub.2.5] is associated with increased levels of circulating endothelin-1 and elevated mean pulmonary arterial pressure. KEY WORDS: air pollution, endothelial dysfunction, endothelin-1, children, particulate matter, pulmonary arterial pressure. Environ Health Perspect 115:1248-1253 (2007). doi:10.1289/ehp.9641 available via http://dx.doi.org/ [Online 27 April 2007]
Activation of the endothelin system and vasoconstriction h1as been reported in animal models (Bouthillier et al. 1998; Kang et al. 2002; Thomson et al. 2004, 2005; Vincent et al. 2001a) [...]