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A study of inflammatory mediators in the human tympanosclerotic middle ear
M Forséni1, D Bagger-Sjöbäck, M Hultcrantz
1Department of Plastic and Reconstructive Surgery, Karolinska Hospital, 171 76 Stockholm, Sweden. marie.forseni@ood.ki.se
Insights
Immunocompetent cells and inflammatory factors like interleukin-6 (IL-6) differ between secretory otitis media and tympanosclerosis. Macrophages, B cells, and IL-6 are prominent in early stages, while inducible nitric oxide synthase is more common in later stages.
Area of Science:
- Otolaryngology
- Immunology
- Cell Biology
Background:
- Secretory otitis media (SOM) and chronic otitis media with tympanosclerosis (COMT) involve inflammation and potential bone remodeling in the middle ear.
- Interleukin-6 (IL-6) and inducible nitric oxide synthase (iNOS) are key inflammatory mediators implicated in tissue repair and remodeling.
Purpose of the Study:
- To investigate the expression of immunocompetent cells (macrophages, T cells, B cells) and inflammatory factors (IL-6, iNOS) in the human middle ear and tympanic membrane.
- To differentiate the cellular and molecular profiles between early-stage (SOM) and late-stage (COMT) otitis media.
Main Methods:
- Immunohistochemical analysis of biopsy specimens from the human middle ear and tympanic membrane.
- Analysis included evaluation of macrophages, T cells, B cells, IL-6, and iNOS expression.
Main Results:
- Biopsies from children with SOM showed significantly higher expression of macrophages, B cells, and IL-6 compared to patients with COMT.
- Biopsies from patients with COMT exhibited greater expression of iNOS than those from children with SOM.
- IL-6 and iNOS were primarily located in surface cells, whereas macrophages and B cells were found deeper within connective tissue or around sclerotic lesions.
Conclusions:
- Distinct patterns of antigen presentation and inflammation are observed in SOM versus COMT.
- Macrophages, B cells, and IL-6 are more prevalent in the early inflammatory phase of secretory otitis media.
- Inducible nitric oxide synthase is more frequently detected in the later, established phase of tympanosclerosis.
Objective:
To analyze immunocompetent cells as well as 2 factors involved in inflammation and also thought to be involved in bone remodeling-interleukin 6 (IL-6) and inducible nitric oxide synthase in the human middle ear, including the tympanic membrane.
Design:
Biopsy specimens were obtained from the human middle ear and tympanic membrane during surgery. Using an immunohistochemical technique, the expression of macrophages, T cells, B cells, IL-6, and inducible nitric oxide synthase were analyzed.
Materials:
Nine biopsy specimens from tympanic membranes in children having a transtympanic ventilation tube inserted as a treatment for secretory otitis media and 11 biopsy specimens from tympanosclerotic plaques from patients with chronic otitis media and tympanosclerosis.
Results:
More positively stained specimens showing macrophages, B cells, and IL-6 were seen in the biopsy specimens from children with secretory otitis media compared with the biopsy specimens from patients with chronic otitis media and tympanosclerosis. The biopsy specimens from patients with chronic otitis media and tympanosclerosis more often showed positive stainings for inducible nitric oxide synthase than the biopsy specimens from children with secretory otitis media. The presence of IL-6 and inducible nitric oxide synthase was shown by staining to be mostly in the surface cells, while macrophages and B cells were stained deeper in the tissues, in connective tissue, or around sclerotic lesions.
Conclusions:
The 2 patient groups differed in antigen presentation so that macrophages, B cells, and IL-6 were labeled more frequently in patients with secretory otitis media, that is, an early phase of the disease. Inducible nitric oxide synthase was seen more frequently in the patients with already established tympanosclerosis in a later phase of the disease.