San‐Marina, Serban

AbstractObjectives/HypothesisCompare proteomic profiles of rabbit vocal folds (VFs) injected with micronized cross‐linked jellyfish collagen “collagen Type 0” (MX‐JC) against two clinical products for injection medialization laryngoplasty (IL).Study DesignAnimal model.MethodsLeft recurrent laryngeal nerve sectioning and IL were performed in New Zealand White rabbits (N = 6/group). Group 1 received (MX‐JC) and adipose‐derived stem cells (ADSCs), Group 2, MX‐JC alone; Group 3, cross‐linked hyaluronic acid; and Group 4, micronized acellular dermis. Animals were sacrificed at 4 and 12 weeks. Proteomic profiling of injected versus noninjected VFs by nano‐liquid chromatography, tandem mass spectrometry, and reactome gene ontology analysis was performed.ResultsOverall, 37–61 proteins were found to be upregulated and 60–284 downregulated in injected versus non‐injected VFs (>1.5 fold, false discovery rate‐adjusted p < .05). Over‐representation analysis (% of total) revealed top up‐regulated pathways at 4 and 12 weeks, respectively: Group 1, keratan sulfate metabolism (46%) and cellular processes (29%); Group 2, extracellular matrix (ECM)/collagen processes (33%) and beta oxidation (39%); Group 3, cellular processes (50%) and energy metabolism (100%); and Group 4, keratan sulfate metabolism (31%) and inflammation (50%). Top downregulated pathways were: Group 1, Inflammation (36%) and glucose/citric acid metabolism (42%); Group 2, cell signaling (38%) and glucose/citric acid metabolism (35%); Group 3, keratan sulfate metabolism (31%) and ECM/collagen processes (48%); and Group 4, glucose/citric acid metabolism (33%) and ECM/collagen processes (43%).ConclusionsMX‐JC “collagen Type 0” upregulates pathways related to ECM/collagen formation and downregulates pathways related to inflammation suggesting that it is promising biomaterial for IL.Level of EvidenceNA

AbstractObjectivesTo examine the degree of agreement between MRI and histologically generated volumetric measurements of residual injection laryngoplasty material.MethodsFollowing left recurrent laryngeal nerve transection, rabbit vocal cords were injected with jellyfish collagen, Cymetra®, or Restylane®. Laryngeal tissue was harvested 4 or 12 weeks post injection followed by MRI imaging and histologic cross‐sectioning. Two raters estimated the volume of remaining injection material in specimens within MRI and histologic axial cross sections. Wilcoxon signed rank tests were employed to detect gross differences between inter‐rater measurements and between imaging modalities across time. Agreement between rater measurements and imaging (histology and MRI) was assessed using intra‐class correlation coefficients.ResultsData was available from 16 rabbits sacrificed at 4 weeks (n = 8) and 12 weeks (n = 8). Inter‐rater testing of MRI imaging revealed no significant differences (p > .05) between rater measurements across time points, and excellent agreement (0.93; 95% confidence interval 0.80–0.98) while histologically estimated volumes demonstrated a significant difference at 4 weeks (p < .05) and overall good agreement (0.89; 95% confidence interval 0.59–0.97). Comparison of MRI and histologically estimated volume measurements revealed significant differences at the 4‐week time point (p < .05) but not at 12 weeks (p > .05). Overall, there is only moderate agreement between MRI and histology estimates (0.72; 95% confidence interval 0.22–0.90).ConclusionsMRI imaging demonstrates good reliability and similar estimates of volume to histologically estimated measurements of residual injection laryngoplasty material at time points clinically relevant for future injection laryngoplasty experiments.Level of EvidenceNA.

AbstractObjectives/HypothesisTest a new jellyfish collagen biomaterial aimed to increase duration of injection medialization laryngoplasty (IL) against two products in clinical practice.Study DesignAnimal model.MethodsLeft recurrent laryngeal nerve sectioning and IL were performed in New Zealand White rabbits (N = 6/group). Group 1 received micronized cross‐linked jellyfish collagen (MX‐JC) and adipose derived stem cells (ADSCs), Group 2, MX‐JC alone, Group 3, cross‐linked hyaluronic acid (X‐HA), and Group 4, micronized acellular dermis (MACD). Animals were sacrificed at 4 and 12 weeks. Major outcomes were MRI tissue volumes and histopathology.ResultsAfter 100 μL IL MRI volumes (means ± STD) at 4 and 12 weeks were: Group 1: 27.2 ± 15.6 and 13.1 ± 5.2 μL, Group 2: 60.8 ± 18 and 27.8 ± 2.47 μL, Group 3: 27.4 ± 12 and 10.6 ± 8 μL, and Group 4: 37.5 ± 11 and 9.85 ± 1 μL. Group 2 volumes were largest and Group 3 were smallest in all comparisons (P < .05). Histologically, low grade inflammatory responses were observed in Group 1, mild histiocytic infiltration in Group 2, widespread muscle fiber loss in Group 3, and plasmocytic infiltration in Group 4.ConclusionsMX‐JC showed the least resorption at 4 and 12 weeks among all groups. T cell inflammatory responses were observed with MX‐JC but were reduced by 12 weeks while B cell immune responses, indicative of antibody priming, were predominantly noted with MACD. MX‐JC + ADSC showed low grade immunity while the XHA showed greater myocyte loss compared to the other groups.Level of EvidenceNA Laryngoscope, 131:E2452–E2460, 2021

Craniofacial reconstruction of critical bone defects typically requires a bone graft. As graft availability may be restricted by disease or comorbidities, tissue engineering approaches are actively sought. The pericranium could provide new bone graft material. During development and repair, bone transitions through a chondrogenic phase. However, with tissue engineering, pluripotent cells can differentiate directly into bone cells. Does ability to recapitulate bone formation in vitro affect osteogenesis and vascularization of pericranium grafts? To answer this, we obtained tissue from nine patients with preplanned craniotomy surgery and studied three-dimensional osteogenesis and angiogenesis of pericranium-derived spheroids. First, we established growth and differentiation conditions on Matrigel. For each spheroid sample, we investigated (i) continuous osteogenic differentiation (COD) and (ii) osteogenic differentiation preceded by chondrogenesis (CD → OD). The effect of vascular endothelial growth factor (VEGF) was compared to VEGF supplemented with fibroblast growth factor, interleukin (IL)-1, IL-6, platelet-derived growth factor, and tumor necrosis factor-α, a growth factor mix (GFM) with possible synergistic effects. In this limited sample, we observed no age- or sex-related differences in cell expansion. Similarly, no statistically significant differences in osteogenic or angiogenic scores between COD or CD → OD spheroids were noted with regular media. In COD, however, VEGF statistically significantly increased angiogenesis compared to control media ( p = 0.007). Also, in COD, both VEGF and VEGF + GFM increased osteogenesis ( p = 0.047 and p = 0.038, respectively). By contrast, in CD → OD, neither VEGF nor VEGF + GFM yielded statistically significant angiogenesis or osteogenesis scores compared to control media. To understand these results, we characterized spheroid protein expression by nanoliquid chromatography coupled to tandem mass spectrometry. Nine angiogenic proteins were either uniquely expressed or upregulated in COD compared to CD → OD: (i) endothelial markers JUP, PTGIS, PTGS2, and TYMP, (ii) tissue remodeling factors CHI3L1 and MMP14, and (iii) metabolic pathways modulators ANGPTL4, ITGA5, and WNT5A. ANGPTL4, ITGA5, PTGIS, PTGS2, and WNT5A define a conserved angiogenic network and were >2-fold increased in VEGF compared to VEGF + GFM. Finally, we examined bone formation on printable poly-(propylene-fumarate) (PPF) scaffolds for individualized grafting. Under COD + VEGF conditions, PPF scaffolds loaded with pericranium-derived cells displayed hallmarks of spongiform-like bone formation. Thus, the human pericranium may be a potential repository for bone-generating cells with applications in craniofacial bone repair using tissue printing.

Objectives/HypothesisVocal fold (VF) paralysis by sectioning the recurrent laryngeal nerve dramatically impacts the life of thyroidectomy patients. Volume‐expanding materials can temporarily restore VF medialization. To prolong this benefit, adipose mesenchymal stem cells (ADSCs) and micronized acellular dermis (MACD) were co‐injected in a rabbit model of injection medialization laryngoplasty. Biomarkers of in situ proliferation were identified by mass spectrometry proteomics and pathway analysis to guide future efforts to increase the length of benefit.MethodsADSCs were expanded and/or differentiated into chondrocytes (CHON) as collagen microspheres. After VF paralysis rabbits received MACD, MACD + undifferentiated ADSC, or MACD+CHON, ADSCs differentiated into chondrocytes. After 12 weeks, animals were sacrificed and 5‐µm paraffin‐embedded cryosections were prepared from larynges for hematoxylin and eosin visualization and nanoflow liquid chromatography electrospray‐ionization tandem‐mass spectrometry analysis of tissue collections. Validated proteins were processed by Venn subtraction and gene ontology (GO) overrepresentation analysis to identify unique pathways and biomarkers.ResultsConfirmed proteins numbered 147 (MACD), 1,243 (MACD+ADSC), and 1,033 (MACD+CHON). Totally, 333 proteins were uniquely found in the MACD+ADSC group, including mesenchymal surface markers CD9, CD44, fibronectin, and vimentin. Over 70% of proteins belonged to catalytic activity and binding GO categories, with the histone (H) family being overrepresented (P < 0.05). Histone variants H3.3, H2A.V, and H2A.Z (associated with open chromatin states) were overrepresented in the MACD+ADSC group, whereas structural histones H2A, H2B, and H4 were not.ConclusionBiomarkers, including atypical histones, are associated with in vivo proliferation of ADSCs and an expanded VF medialization volume.Level of EvidenceNA Laryngoscope, 128:E402–E408, 2018

Objectives/HypothesisRadiation plays a prominent role in advanced stage head and neck tumors. Often, the radiated area includes adjacent nonmalignant mesenchymal tissue, which contains a mixture of cells that has been shown to accelerate wound healing. The purpose of this study is to determine the long‐term effect of radiation on the expansion potential of adipose‐derived stromal/stem cell (ADSC) tissue and on the ability of resident stem cells in this fraction to undergo phenotypic differentiation.Study Design/Methods: After institutional review board approval, 12 patients with a history of head and neck radiation and pending surgery were enrolled. Adipose tissue was collected from irradiated tissue (XRT) and nonirradiated tissue (NRT) sites. Mesenchymal stem cells were isolated from these populations, with subsequent assessment of cellular kinetics and differentiation potential between harvest sites.ResultsAdipose‐derived stromal/stem cells could not be isolated from XRT in six patients due to lack of in vitro cell proliferation. For the remaining six patients, overall cumulative population‐doubling time was longer for XRT relative to NRT (29.3 vs. 11.5 days; P = 0.02). However, no significant differences were observed in cell generation time or viability. When XRT and NRT ADSC fractions were grown to standardized concentrations and incubated under conditions that induce phenotypic differentiation of resident stem cells, no significant changes in chondrogenic, adipogenic, or osteogenic differentiation were observed.ConclusionThese preliminary observations suggest that irradiated ADSCs close to the surgical site undergo long‐term changes in proliferative capacity. The potential for phenotypic differentiation is retained, however, in ADSCs that survive the irradiation process.Level of Evidence2b.