Cytokines and Defensins in Tissue Biopsies Obtained by Bronchoscopy from Patients with Post-Intubation Tracheal Stenosis

Aims: The objective of our study was to perform the routine analysis of bronchoscopically obtained tracheal samples to determine the appearance and relative distribution of cytokines and antimicrobial proteins in patients with post-intubation tracheal stenosis (PITS).

Study Design: Retrospective.

Place and Duration of Study: Rīga Stradiņš University, Institute of Anatomy and Anthropology, Pauls Stradiņš Clinical University Hospital, between May 2014 and May 2015.

Methodology: Five patients with PITS were involved in this study. Tissue samples were obtained by bronchoscopy from the upper part of trachea, then proceeded for routine histological staining with hematoxylin and eosin. Interleukine-1 (IL-1), interleukine-10 (IL-10) and tumor necrosis factor alpha (TNFα), as well as beta defensin-2 (β def-2) were detected by use of immunohistochemistry (IMH) method. The number of immunoreactive (positive) structures was graded semi-quantitatively.

Results: Squamous metaplasia, inflammatory cell infiltration and formation of granulation tissue were observed in all cases. Significant expression of IL-10 and β def-2 was seen as various number of immunoreactive structures in tracheal tissue. Only few scattered IL-1 and TNFα positive macrophages were found in part of cases.

Conclusions: The leading role in pathogenesis of post-intubation tracheal stenosis is assumed to be the chronic inflammation, fibrous scarring, as well as the remodeling of tracheal wall due to the ischemia. Compensatory expression of antimicrobial peptide β def-2 and anti-inflammatory cytokine IL-10 indicates the intense local tissue defense reactions. TNFα and IL-1 are not among the most significant factors in pathogenesis of PITS.