Maternal cigarette smoking and alveolar wall elastin in the infant lung

The harmful effects of maternal cigarette smoking to infants include reduced lung function in the neonatal period, increased airway responsiveness to inhaled agonists, and increased frequency of asthma exacerbations. Animal models of in utero smoke exposure have shown reduced amounts of elastin in alveolar walls with an increase in size, but a reduction in the number, of saccules in the lungs of smoke-exposed animals (Pediatr.Res. 1985:19:408-412). We hypothesised that infants exposed to maternal cigarette smoke would have reduced elastin in their alveolar walls. We measured the amount of elastin in the alveolar walls of infants (n=12) who died of SIDS and had been exposed to maternal cigarette smoke (20 cigarettes a day) during pregnancy and up to the time of death and compared these findings with those from infants (n=9) who also died of SIDS but had no maternal cigarette smoke exposure. Sections of lung parenchyma were stained with Resorcin-Fuchsin. The percentage of elastin in the alveolar wall was determined by point counting on 10 random high power fields (x400). The ratio of airspace to tissue (a marker of inflation) was also estimated. Results are expressed as mean standard error. Gestation Birth weight age Airspace Elastin (week) (kg) (mehs) (%) (%) Non smoke 39 ± 0.6 3.9 ± 0.6 5 ± 0.9 64 ± 2 10 ± 0.6 Smoke exp 38 ±0.5 3.0 ±0.1 4 ± 0.9 64 ±2 9.5 ± 0.6 p value n.s. n.s. n.s. n.s. n.s. These findings suggest that maternal cigarette smoke exposure does not have a significant effect on the amount of elastin in the alveolar wall in infants.