Nasal biopsies of children exposed to air pollutants

Southwest Metropolitan Mexico City (SWMMC) atmosphere is a complex mixture of air pollutants, including ozone, particulate matter, and aldehydes. Children in SWMMC are exposed chronically and sequentially to numerous toxicants, and they exhibit signiecant nasal damage. The objective of this study was to assess p53 accumulation by immunohistochemistry in nasal biopsies of SWMMC children. We evaluated 111 biopsies from 107 children (83 exposed SWMMC children and 24 control children residents in a pollutant-compliant Caribbean island). Complete clinical histories and physical examinations, including an ear‐nose‐throat (ENT) exam were done. There was a signie cant statistical difference in the upper and lower respiratory symptomatology and ENT endings between control and exposed children (p < 0.001). Control children gave no respiratory symptomatology in the 3 months prior to the study; their biopsies exhibited normal ciliated respiratory epithelium and were p53-negative. SWMMC childrencomplainedofepistaxis,nasalobstruction,andcrusting.Irregularareasofwhitish-grayrecessedmucosaovertheinferiorandmiddleturbinates were seen in 25% of SWMMC children, and their nasal biopsies displayed basal cell hyperplasia, decreased numbers of ciliated and goblet cells, neutrophilic epithelial ineltrates, squamous metaplasia, and mild dysplasia. Four of 21 SWMMC children with grossly abnormal mucosal changes exhibited strong transmural nuclear p53 staining in their nasal biopsies (p 0.005, odds ratio 26). In the context of lifetime exposures to toxic and potentiallycarcinogenic air pollutants, p53 nasal induction in children could potentially represent. a) acheckpoint responsetotoxic exposures, setting up a selective condition for p53 mutation, or b) a p53 mutation has already occurred as a result of such selection. Because the biological signiecance of p53 nuclear accumulation in the nasal biopsies of these children is not clear at this point, we strongly suggest that children with macroscopic nasal mucosal abnormalities should be closely monitored by the ENT physician. Parents should be advised to decrease the children’s number of outdoor exposure hours and encourage a balanced diet with an important component of fresh fruits and vegetables.