Jiri Prazma, MD, PhD

Jiri Prazma, MD, PhD, and his colleagues have continued in their study of allergy-induced Eustachian tube dysfunction. The role of allergy in the development of Eustachian tube dysfunction (ETD) and otitis media with effusion (OME) has been investigated in the laboratory for many years. While the etiology of OME most likely involves many factors, allergic inflammation in and around the nasopharyngeal portion of the Eustachian tube (ET) or within the middle ear leads to the breakdown of the protective functions of the ET, thereby resulting in increased risk for the development of otitis media. For this reason, it is theorized that by modulating the pathways that lead to the allergic response, we can limit the inflammation caused by the allergic response resulting in ETD.

We have developed a model of ETD where rats are sensitized to ova-albumin (OVA) and subsequently challenged with this allergen either transtympanically or through the nasopharynx. This challenge causes an allergic-like response leading to inflammation within the middle or around the nasopharyngeal portion of the ET. This inflammation consequently leads to worsening of the ET’s ventilatory function manifested as increased passive opening and closing pressures as well as worsening of active clearance of negative pressure. It also impairs the mucociliary clearance of the ET.

Supported by the Resident Research Grant of the American Academy of Otolaryngic Allergy, Rose J. Eapen, MD, resident in the research track, has investigated a new and influential mediator of allergic inflammation, immunomodulatory oligodeoxynucleotides (IMOs). Studies have shown that these types of oligodeoxynucleotides were efficacious in the treatment of allergic-like airway inflammation and airway hyperresponsiveness by preventing naive T-lymphocyte differentiation. In addition, IMOs demonstrated a potent effect on early and late phase allergic airway responses by reducing eosinophils, IL-10, IL-4, IL-5, and IL-6. However, there has been no research investigating the ability of these drugs to inhibit allergy induced OME. Dr. Eapen continues to investigate the role of allergy while middle ear effusions are induced by LPS administered into the middle ear in ovalbumin sensitized Brown Norway rats.

Conclusion: IMO given via transtympanic or nasopharyngeal application can treat allergy-induced ETD in rats. IMO may offer substantial promise in the future management of OME. Treatment with IMOs prevented OVA-induced allergic Eustachian tube inflammation in the rat and in the future may provide a useful agent in the management of allergy-induced OME in children. The role of ovalbumin-induced allergy on LPS-induced middle ear effusions are presently being investigated.