Assessment of cricopharyngeal muscle aging with apoptotic markers.

Objectives: The aims of this study were to evaluate histochemical markers of apoptosis in the cricopharyngeus muscle, which is the gatekeeper of the pharyngoesophageal region during the swallowing process; to investigate the effects of primary aging on this muscle; and to determine whether a relationship exists with gastroesophageal reflux disease.

Materials And Methods: The study included 30 fresh cadavers with a time of death of 12 hours or less obtained from the Turkish Ministry of Justice Forensic Medicine Unit. All cadavers were dissected with routine postmortem skin incisions to extract specimens from the cricopharyngeus muscle and the esophagocardiac junction mucosa. Muscle degeneration and primary aging were demonstrated by immunodetection of Bax, Bcl-2, and Caspase-3 proteins as markers of the apoptosis. Esophageal specimens were examined for the presence of reflux esophagitis.

Results: The mean age was 41.5 (14-74) years, and the study included 18 male and 9 female cadavers. Three of them were excluded because of fixation artifacts. The mean Bax, Bcl-2, and Caspase scores showed no statistically significant relationship with age (P = 0.94). The right and left sides of the muscle were investigated separately, and the Bax scores of the right side of the cricopharyngeus muscle showed a statistically significant decrease with age (P = 0.026), whereas the Bax and Bcl-2 scores were increased with age (P = 0.035 and 0.049, respectively) on the left side. Evaluation of the 23 esophagus specimens revealed 10 cases of esophagitis. No relationship was found between the mean of each apoptotic marker and esophagitis.

Conclusions: It is histopathologically not possible to demonstrate muscle death due to either primary aging or reflux. This might be attributable to the defensive capability of this unique muscle to maintain the feeding process.