Speaker
Description
"Introduction
Tympanic membrane perforations (TMP) represent a common cause of visit to the ENT clinic, usually due to recurrent infections or trauma. The rate of recovery for each perforation depends mainly on the size of the perforation and the secondary infections developed. Although most TMPs heal spontaneously, some patients can develop a chronic defect. The traditional technique used in the treatment of TMP, known as myringoplasty, uses temporalis muscle fascia or tragal cartilage perichondrium, with its associated with patients’ morbidity and high healthcare expenses. Thus, there is growing interest in the application of biocompatible materials such as scaffolds for regeneration. The aim of this study is the development and validation of a protein-based biomaterial scaffold to be used as a carrier in tympanic membrane restoration.
Methodology
Scaffolds were designed based on porcine gelatin. Subsequently, the scaffold was characterised by water uptake, water vapour transmission rate and degradation degree analyses. Moreover, mechanical properties were evaluated by means of puncture and mucoadhesion tests. Finally, the biocompatibility of the scaffold was analysed by exposition to a fibroblast cell line. In light of these results, a pilot in vivo study was conducted in a rat model with chronic TMP in order to study the tympanic membrane (TM) substitute integration, regeneration and functionality. For that aim, first, the perforation was created on both TMs by applying mitomycin C before the incision and dexamethasone after the procedure. The perforations were evaluated during 8 weeks by otoendoscopic observation and those who became chronic were included. The designed scaffold was placed into the study ear after margin scar tissue removal covering the previously created defect. Afterwards, the perforation was being monitored for 2 months by closure level measurement and blood analysis. After this time, the animal will be sacrificed, and tissue will be removed from the implantation site to evaluate the regeneration degree and the response of the graft in the host.
Results
Regarding the in vitro characterisation, the substitute showed adequate hydration and permeability properties, and did not degrade when exposed to water following 6 months. Mechanical properties, pressure resistance and adhesion capacity, of biomimetic substitutes were similar or superior to those reported in the literature for native TM. The scaffolds were fully biocompatible with no relevant affection of cell viability over one-week period.
Concerning the in vivo study, the chronic TM defect was successfully created in the 60% of the cases. After scaffold placement, otoscopic observations seem to show integration of the TM substitute without apparent swelling.
Conclusion
The designed gelatin-based biomimetic TM substitute showed intrinsic and functional properties in vitro that make it suitable as a support for the regeneration of chronic TMP. Due to its intrinsic properties, it allows the maintenance of a suitable environment for wound closure and its functional properties facilitate manipulation and adaptation to the type of pathology. In view of the results compiled from the in vivo trial, this substitute could allow TMP closure without causing any adverse response."
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