Objective/Hypothesis Mesenchymal stem cells (MSCs) originally isolated from bone marrow, are fibroblast-looking cells that are now assumed to be present in the stromal component of many tissues. MSCs are characterized by a certain set of criteria including their growth culture characteristics, a combination of cell surface markers, and the ability to differentiate along multiple mesenchymal tissue lineages. We hypothesized that human vocal fold fibroblasts (hVFF) isolated from the lamina propria meet the criteria established to define MSCs and are functionally similar to MSCs derived from BM and adipose tissue. Study Design In vitro study Methods HVFF were previously derived from human vocal fold tissues. MSCs were derived from adipose tissue (AT), and BM of healthy donors, based on their attachment to culture dishes and their morphology, and expanded in culture. Cells were analyzed for standard cell surface markers identified on BM-derived MSCs as well as the ability to differentiate into cells of mesenchymal lineage, i.e. fat, bone and cartilage. We investigated the immunophenotype of these cells before and after interferon-γ (INF- γ) stimulation. Results HVFF displayed cell surface markers and multipotent differentiation capacity characteristic of MSCs. Furthermore, these cells exhibited similar patterns of expression of HLA and co-stimulatory molecules, after stimulation with INF- γ compared to MSCs derived from BM and AT. Conclusions Based on our findings hVFF derived from lamina propria have the same cell surface markers, immunophenotypic characteristics, and differentiation potential as BM- and AT-derived MSCs. We propose VF fibroblasts are MSCs resident in the vocal fold lamina propria.

Objectives-To determine if the utilization of injectable chemically-modified hyaluronan (HA) derivative at the time of intentional vocal fold resection may facilitate wound repair and preserve the unique viscoelastic properties of the extracellular matrix and lamina propria 6 months after treatment.Study Design-Prospective, controlled animal study.Methods-Twelve rabbit vocal folds were biopsied bilaterally, and the left side of vocal fold was treated with Extracel, an injectable, chemically-modified HA derivative, and the right side of vocal fold was injected with saline as control at the time of resection. Animals were sacrificed six months after biopsy and injection. Outcomes measured include transcription levels for procollagen, fibronectin, fibromodulin, TGF-β1, hyaluronan synthase and hyaluronidase and tissue biomechanics --viscosity and elasticity.Results-Extracel treated vocal folds were found to have significantly less fibrosis than saline treated controls. Extracel treated vocal folds had significantly improved biomechanical properties of elasticity and viscosity. Significantly decreased levels of fibronectin, fibromodulin, TGF-β1, procollagen I and hyaluronan synthase were measured.Correspondence to: Susan L. Thibeault, thibeault@surgery.wisc.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Conclusions-Prophylactic in vivo manipulation of the extracellular matrix with an injectable HA hydrogel appears to induce vocal fold tissue regeneration to yield improved tissue composition and biomechanical properties at 6 months. NIH Public Access

TNF (designated as TNF-α under previous nomenclature) is the preeminent activator of MMP-9 generation from a variety of cells including eosinophils. We have previously established that TNF strongly synergizes with IFN-γ and IL-4 for eosinophil synthesis of Th1- and Th2-type chemokines respectively. Thus, we sought to determine if TNF-induced synthesis of MMP-9 would be enhanced by the presence of Th1, Th2, or the eosinophil-associated common beta chain (βc) cytokines. Human blood eosinophils were cultured with TNF alone or in combination with either IFN-γ, IL-4, IL-3, IL-5, or GM-CSF. Concentrations and activities of MMP-9 in eosinophil culture supernates were measured by ELISA and gelatin zymography, mRNA transcription and stabilization by quantitative real-time PCR, and signaling events by immunoblotting and intracellular flow cytometric analysis. Singularly, TNF, GM-CSF, or IL-3, but not IL-4 or IFN-γ, induced relatively small (<0.2 ng/ml) but statistically significant quantities of MMP-9. Remarkable synergistic synthesis of MMP-9 (ng/ml levels) occurred in response to TNF plus IL-3, GM-CSF or IL-5, in the order of IL-3>GM-CSF>IL-5. Zymography revealed that eosinophils release MMP-9 in its pro-form. Eosinophil stimulation with the combination of IL-3 plus TNF led to increased steady-state levels of MMP-9 mRNA, prolonged mRNA stabilization, and enhanced activation of ERK1/2 phosphorylation. Inhibition of NF-κB, MEK kinase, or p38 MAP kinase, but not JNK signaling pathways, diminished IL-3/TNF-induced MMP-9 mRNA and protein production. Thus, the synergistic regulation of eosinophil MMP-9 by IL-3 plus TNF likely involves cooperative interaction of multiple transcription factors downstream from ERK, p38, and NF-κB activation as well as post-transcriptional regulation of MMP-9 mRNA stabilization. Our data indicate that within microenvironments rich in βc-family cytokines and TNF, eosinophils are an important source of proMMP-9 and highlight a previously unrecognized role for synergistic interaction between TNF and βc-family cytokines, particularly IL-3, for proMMP-9 synthesis.

Objective To determine the effectiveness of bone marrow mesenchymal stem cell (BM-MSC) transplantation in isolation or within a synthetic extracellular matrix (sECM) for tissue regeneration of the scarred vocal fold lamina propria. Methods In vitro stability and compatibility of mouse BM-MSC embedded in sECM was assessed by flow cytometry detection of BM-MSC marker expression and proliferation. Eighteen rats were subjected to vocal fold injury bilaterally, followed by one month post-treatment with unilateral injections of saline or sECM hydrogel (Extracel), GFP-mouse BM-MSC or BM-MSC suspended in sECM. Outcomes measured one month after treatment included procollagen-III, fibronectin, hyaluronan synthase-III (HAS3), hyaluronidase (HYAL3), smooth muscle actin (SMA) and transforming growth factor-beta 1(TGF-β1) mRNA expression. The persistence of GFP BM-MSC, proliferation, apoptosis and myofibroblast differentiation was assessed by immunofluorescence. Results BM-MSC grown in vitro within sECM express Sca-1, are positive for hyaluronan receptor CD44 and continue to proliferate. In the in vivo study, groups injected with BM-MSC had detectable GFP-labeled BM-MSC remaining, showed proliferation and low apoptotic or myofibroblast markers compared to the contralateral side. Embedded BM-MSC in sECM group exhibited increased levels of procollagen III, fibronectin and TGF-β1. BM-MSC within sECM downregulated the expression of SMA compared to BM-MSC alone, exhibited upregulation of HYAL3 and no change in HAS3 compared to saline. Conclusions Treatment of vocal fold scarring with BM-MSC injected in a sECM displayed the most favorable outcomes in ECM production, hyaluronan metabolism, myofibroblast differentiation and production of TGF-β1. Furthermore, the combined treatment had no detectable cytotoxicity and preserved local cell proliferation.