(A1120) Immunohistochemical Analysis of Cellularity in Nasal Polyp Tissue

Introduction: Nasal polyps (NP) are a common form of chronic rhinosinusitis (CRS), where inflammatory cell infiltrates play a large role in underlying physiology. Most ex-vivo models of CRS focus on a specific cell type, and are limited by lack of the ability to test intercellular communication or multicellular actions. The study objective was to test a novel experimental model of fresh ex-vivo study of CRSwNP tissues, where biospecimens are maintained in standard cell culture conditions over the period of three days.

Methods: Surgical tissues from two CRSwNP patients were cultured in standard cell culture conditions for a duration of 24, 48, and 72 hours. Tissues were fixed in formalin and paraffin embedded, and immunohistochemical (IHC) staining for leukocytes, mast cells, and neutrophils was performed in triplicate for each subject. Analysis was performed using traditional cells per high power field (HPF) count, and by using ImageJ software for semi-automatic cell quantification.

Results: Cellularity was demonstrated in nasal polyp tissues cultured for 24, 48 and 72 hours under standard conditions. Immunohistochemical staining demonstrated all three immune cell types across all time points. Mean cell counts were highest at 48 hours before decreasing slightly at 72 hours. (Average ∆ ~73 cells). Quantification using both traditional HPF count, and semi-automatic ImageJ analysis confirmed consistent detection through 72 hours.

Conclusions: Ex-vivo polyp tissue models may be an exciting new experimental consideration for study of inflammatory processes and testing novel therapies. Standard culture conditions appear to be sufficient at least for a limited period of time. Further study using flow cytometry and other methods can be used to test and confirm these findings in various cell culture conditions.