Apoptosis in the developing human cricoid cartilage: a pilot study.

Apoptosis is widely recognized as a major phenomenon in normal development. Deficiencies in this process may lead to developmental abnormalities such as congenital subglottic stenosis. We studied apoptosis using in situ end labeling of the 3'-OH ends of fragmented DNA in 5 progressively older, normal, human cricoid cartilage specimens. Results show that apoptosis is a very active process in fetal and neonatal tissue. The process gradually slows with advancing age. In the 4- and 13-year-old specimens, minimal to no apoptosis was seen. We conclude that apoptosis plays a critical role in the intraluminal and extraluminal expansion of the cricoid cartilage.