Study of Angiogenic, Pro-Apoptotic, and Pro-Inflammatory Factors in Congenital and Acquired Cholesteatomas.

Abstract

Despite recent advances in biomolecular research that have improved our knowledge of cholesteatoma pathogenesis, the reasons behind its highly variable clinical course are still not clarified. It has been proposed that biological signaling between peri-matrix and matrix cells could play a critical role in disease homeostasis. The aim of our study was to analyze the expression of inflammatory (IL-1β), hyper-proliferative (STAT-3, TGF-β), and angiogenic (VEGF-C, PDGFr) factors in congenital and acquired cholesteatomas (both in adults and children), which might correlate with the clinical features observed. We performed an experimental study on 37 patients (29 males and 8 females, ranging from 4 to 66 years of age) who were diagnosed with cholesteatoma between 2020 and 2021 in our institution. All patients underwent clinical, audiologic, and radiologic assessments. Bone erosion grading and staging of cholesteatoma growth were assessed through preoperative evaluation and intraoperative middle ear findings, according to the PTAM System proposed by the Japan Otological Society (2016). Retro-auricular skin specimens were intraoperatively collected in all patients. Skin and cholesteatoma samples were analyzed through histopathological, western blot, and immunohistochemical evaluations. The expression rate was measured to find out the differences between congenital and acquired cholesteatomas as well as between the adult and pediatric populations. Expression of angiogenic, inflammatory, and proliferative biomarkers is significantly increased in acquired cholesteatomas in children as compared to congenital and acquired forms in adults, in accordance with the higher stage of disease shown by imaging, surgical, and histological features. Our data suggest that pathways already supposed to be involved in the pathogenesis of cholesteatomas could be differently activated in more destructive forms, typically found in children. The identification of potential biomarkers of cholesteatoma aggressiveness could lead to more personalized management (timing of intervention, recurrence prevention) and the future identification of anti-growth/anti-proliferative agents as non-surgery therapeutic options.