Role of HIF-1α and CASPASE-3 in cystogenesis of odontogenic cysts and tumors.

OBJECTIVES: Odontogenic cysts and tumors are the most relevant lesions that affect the gnathic bones. These lesions have in common the formation of cystic areas and this common feature may suggest involvement of similar mechanisms. The hypoxia inducible factor 1 alpha (HIF-1α), a responsive protein to hypoxia and caspase-3, an irreversible apoptosis marker, may contribute to cyst formation. Thus, this study aimed to investigate the immunoexpression of these proteins in odontogenic cysts and tumors. MATERIAL AND METHODS: Twenty cases of ameloblastoma, keratocystic odontogenic tumor (KOT) (n = 20), radicular cyst (RC) (n = 18), dentigerous cyst (DC) (n = 11), calcifying cystic odontogenic tumor (n = 8), and dental follicle (DF) (n = 10) were used to investigate HIF-1α and caspase-3 expression in sequential serial cuts by immunohistochemistry. RESULTS: HIF-1α was overexpressed in RC, DC, and ameloblastoma when compared with DF. The basal and sometimes the lower suprabasal layer showed no or very low expression in DC, KOT, and ameloblastoma, the last also showing strong expression in solid epithelial areas and initial cystic formation regions. Caspase-3 was found to be overexpressed in all lesions, with the highest expression in odontogenic cysts compared to tumors. HIF-1α and caspase-3 were localized in similar areas of the same lesions, especially in the epithelium surrounding cystic formations. CONCLUSIONS: This study showed distinct immunoexpression of HIF-1α and caspase-3 in odontogenic cyst and tumors, with higher expression observed in odontogenic cysts. CLINICAL RELEVANCE: These findings suggest a possible correlation between hypoxia, apoptosis, and cystogenesis, leading to understand the mechanisms responsible to cystic formation in odontogenic lesions.

Environmental tobacco smoke and interleukin 4 polymorphism (C-589T) gene: environment interaction increases risk of wheezing in African-American infants.

OBJECTIVES: To determine whether infants exposed to environmental tobacco smoke (ETS) having the interleukin 4 (IL-4) or interleukin 13 (IL-13) gene polymorphisms were at increased risk of wheezing. STUDY DESIGN: A birth cohort of 758 infants was evaluated annually by a questionnaire, physical examination, and skin prick testing. DNA samples from 560 children were genotyped for IL-4 C-589T and IL-13 C-1112T. The relationship of ETS exposure and genotype with the outcome of wheezing was analyzed. RESULTS: At the time of evaluation, mean age was 13.4 +/- 2.2 months. The prevalence of sensitization was 29%, and wheezing without a cold was 26.2%. The interaction of ETS exposure and the CT/TT genotypes for IL-4 C-589T showed a significant association with wheezing (odds ratio: 10.84; 95% confidence interval: 1.12-104.64, P = .04) in African-American infants. CONCLUSIONS: In African-American infants with a family history of atopy, the interaction of ETS and IL-4 C-589T demonstrated a 10-fold risk associated with wheezing without a cold.