Age-related Histological Changes in Subjects with Nasal Polyps and Healthy Controls
METHODS: Sinonasal tissues from young (18-49 yr), mature (50-64 yr), and older adults (≥65 yr) with NP and from age-matched healthy controls were collected during surgery. Sinonasal tissues from young (2 months) and aged (24 month) mice were also obtained. For age related histopathological changes, tissues were embedded in paraffin, sectioned, and processed with periodic acid-Schiff (PAS) staining and Masson’s trichrome staining.
RESULTS: The overall volume of submucosal glands and the proportion of mucus cells/serous cells in healthy subjects was increased with age. Goblet cell hyperplasia, a decrease in the volume of submucosal glands, and epithelial cell metaplasia with increased thickness of epithelial layer was observed in NP subjects versus healthy controls, regardless of age. There was significantly more goblet cell hyperplasia, increased thickness of the epithelial layer with increased eosinophil infiltration, and more submucosal glandular proliferation in older adults with NP compared to Young ones with NP. Consistent with this human data, aged mice showed goblet cell hyperplasia and increased proportion of PAS-positive area in submucosal glands. Interestingly, there was remarkably increased collagen deposition in aged mice compared to young mice.
CONCLUSION: Significant histological differences in subjects with NP and healthy controls exist among different age groups. These age-related histological changes may be related to higher prevalence of NP in the older population. The mechanisms and functional consequences of these changes need further investigation.