Marina, Serban San

Objectives/HypothesisDesign and test a novel biomaterial for injection laryngoplasty aimed to increase the duration of effectiveness of micronized acellular dermis.Study DesignAnimal model.MethodsInjection laryngoplasty was performed in three groups (n = 5) of New Zealand White rabbits. Acellular dermis was either used alone as a control (group 1), was combined with undifferentiated stem cells (group 2), or with predifferentiated chondrocytic cells (group 3). Groups 2 and 3 were supplemented with growth factors. Animals were sacrificed 4 and 12 weeks after laryngoplasty and histologic analysis was completed. The major outcome measure was volume of tissue remaining.ResultsAfter 4 weeks, the mean volume of tissue remaining was 341 ± 89 mm3, 295 ± 102 mm3, and 133 ± 15 mm3, for groups 1 to 3, respectively. At the 12‐week time point, volumes were 62 ± 62 mm3, 235 ± 35 mm3, and 107 ± 99 mm3. After 12 weeks, there was a significantly higher volume in group 2 compared to group 1 or 3 (P = .01, P = .04). Volumes between week 4 and week 12 were significantly lower in group 1 (P = .02), but not significantly different for groups 2 and 3 (P = .38, P = .74). Histologic evaluation revealed a robust lymphocytic infiltration in all cases as well as morphologic and immunophenotypic features suggestive of chondrogenic differentiation in a single animal.ConclusionsMicronized acellular dermis combined with stem cells and growth factors showed significantly less resorption 12 weeks after injection laryngoplasty compared to micronized acellular dermis alone. Groups using novel tissue‐engineered biomaterial showed a lower resorption rate over time compared with acellular dermis alone.Level of EvidenceNA. Laryngoscope, 128:160–167, 2018

ObjectiveHuman adipose‐derived mesenchymal stem cells (ADSCs) were used to rehabilitate bone damaged by osteoradionecrosis (ORN) in an established animal model.Study DesignProspective animal study.SettingAcademic department laboratory.Subjects and MethodsAfter institutional review board and Institutional Animal Care and Use Committee approval, 24 athymic nude rats were divided into 5 groups: 4 groups irradiated (20 Gy) by brachytherapy catheter placed at the left hemimandible and 1 mock irradiation control (n = 4). For all groups, ORN was initiated by extraction of the central molar 1 week later. After 28 days, animals (n = 5/group) received injection at the extraction site with saline (SAL), ADSCs, platelet‐rich plasma and collagen (PRP/COL), or ADSCs + PRP/COL. Rats were sacrificed 28 days later and their mandibles harvested for histopathology analysis (osteoblasts, osteoclasts, and fibrosis) and bone volume measurement using 3‐dimensional micro–computed tomography.ResultsAll but 1 rat survived the experiment period (23/24). Radiographic and histological analysis revealed 60% bone loss in the SAL group compared with the nonirradiated control. Injection of ADSCs increased jaw region bone volume by up to 36% (P <. 01). All experimental groups (ADSC, PRP/COL, and ADSC + PRP/COL) showed dramatically decreased osteoclast counts (P <. 001) while injection of PRP/COL with or without ADSCs increased osteoblasts. Increased fibrosis was observed after ADSC injection (P <. 05).ConclusionThe application of human ADSCs to an induced mandibular osteoradionecrosis model in athymic rats results in increased deposition or preservation of bone, demonstrated both histologically and radiographically. This offers an encouraging possible treatment option for translational research in this difficult disease.

Objectives/HypothesisMicronized AlloDerm is a commonly used injectable material for injection laryngoplasty; however, the histologic response to laryngeal implantation and resorption rate over time have not been elucidated. This study aimed to evaluate the in vivo response of micronized AlloDerm over time after laryngeal implantation using a rabbit model.Study DesignAnimal model.MethodsThe left recurrent laryngeal nerve was sectioned in five New Zealand White rabbits to create a vocal cord paralysis. Two weeks later, injection laryngoplasty was performed with 100 μL of micronized AlloDerm. Animals were sacrificed 4 (two rabbits) and 12 (three rabbits) weeks after injection. Histologic sections were stained and evaluated by a single pathologist. Volume estimates were made by assuming the implant took an ellipsoid shape using dimensions calculated from histologic slides.ResultsIn all cases, histological analysis revealed a lymphocytic inflammatory response infiltrating the peripheral margins of injection. After 4 weeks, the volume of injected material remaining in two rabbits was 404 and 278 mm3 (average 341 mm3). After 12 weeks, the volume of injected material remaining in three rabbits was 0, 61, and 124 mm3 (average 62 mm3), an 82% difference in volume of material between animals sacrificed at 4 weeks versus 12 weeks.ConclusionsInjection laryngoplasty using micronized AlloDerm induces a lymphocytic inflammatory response after injection in a rabbit model. Though a significant amount of material remains after 4 weeks, by 12 weeks the majority has been reabsorbed.Level of EvidenceNA Laryngoscope, 127:E166–E169, 2017