Reversal of Vocal Fold Mucosal Fibrosis Using siRNA against the Collagen-Specific Chaperone Serpinh1

Comprehensive analysis of lncRNA-miRNA-mRNA ceRNA network in ischemic stroke

Objective

Competitive endogenous RNA (ceRNA) networks have uncovered a novel mode of RNA interaction, and are implicated in various biological processes and the pathogenesis of IS. This study aimed to explore the potential mechanisms underlying the ceRNA network in IS.

Methods

Four public datasets containing lncRNA and mRNA (GSE22255 and GSE16561) and miRNA (GSE55937 and GSE43618) expression profiles from the GEO database were systematically analyzed to explore the role of RNAs in ischemic stroke (IS). Differentially expressed mRNAs (DEmRNAs), lncRNAs (DElncRNAs), and miRNAs (DEmiRNAs) between IS and normal control samples were identified. LncRNA-miRNA and miRNA-mRNA interactions were predicted, and the competing endogenous RNA (ceRNA) regulatory network was constructed using the Cytoscape software. The correlation between the RNAs in the ceRNA network and the clinical features of the samples was evaluated. Finally, principal component analysis was performed on the RNAs that constitute the ceRNA regulatory network, and their differential expression and principal component relationships among different types of samples were observed.

Results

A total of 224 DEmRNAs, 7 DEmiRNAs, and four DElncRNAs related to IS in four datasets were identified. Then, through target gene prediction, a lncRNA-miRNA-mRNA ceRNA network that contained 3 DElncRNAs, 2 DEmiRNAs, and 24 DEmRNAs was constructed. Correlations of the clinical characteristics showed that PART1 and SERPINH1 were related to clinical diseases, WNK1 was related to lifestyle, and seven RNAs were related to age. PCA results indicate that three principal components of PC1, PC2, and PC3 can clearly distinguish between control and IS samples.

Conclusion

Overall, we constructed a ceRNA network in IS, which could offer insights into the molecular mechanism and potential prognostic biomarkers for further research.

Drug delivery systems for wound healing treatment of upper airway injury

INTRODUCTION

Endotracheal intubation is a common procedure to maintain an open airway with risks for traumatic injury. Pathological changes resulting from intubation can cause upper airway complications, including vocal fold scarring, laryngotracheal stenosis, and granulomas and present with symptoms such as dysphonia, dysphagia, and dyspnea. Current intubation-related laryngotracheal injury treatment approaches lack standardized guidelines, relying on individual clinician experience, and surgical and medical interventions have limitations and carry risks.

AREAS COVERED

The clinical and preclinical therapeutics for wound healing in the upper airway are described. This review discusses the current developments on local drug delivery systems in the upper airway utilizing particle-based delivery systems, including nanoparticles and microparticles, and bulk-based delivery systems, encompassing hydrogels and polymer-based approaches.

EXPERT OPINION

Complex laryngotracheal diseases pose challenges for effective treatment, struggling due to the intricate anatomy, limited access, and recurrence. Symptomatic management often requires invasive surgical procedures or medications that are unable to achieve lasting effects. Recent advances in nanotechnology and biocompatible materials provide potential solutions, enabling precise drug delivery, personalization, and extended treatment efficacy. Combining these technologies could lead to groundbreaking treatments for upper airways diseases, significantly improving patients' quality of life. Research and innovation in this field are crucial for further advancements.

Effects of compound betamethasone on vocal fold wound healing in rabbit model: A preliminary study

Objectives

The compound betamethasone is widely used to prevent scarring in dermatology. This study aims to explore the effects of compound betamethasone on vocal fold (VF) wound healing.

Study design

Prospective animal study in rabbits.

Methods

Eighteen rabbits underwent bilateral VF stripping and three rabbits served as controls. 0.1 mL of compound betamethasone (1 mL: betamethasone sodium phosphate 5 mg and betamethasone dipropionate 2 mg) was injected into the right VF of each rabbit, and 0.1 mL 0.9% saline was injected into the contralateral VF. Endoscopy was performed for morphologic observation. Six larynges were harvested for histological analysis at 3 days, 7 days, and 1 month. The VFs were stained with hematoxylin and eosin (H&E), Alcian blue, and Masson' trichrome staining.

Results

In morphological analysis, there was no visible difference between betamethasone-treated and saline-treated VFs at 3 and 7 days. After 1 month, more VF scars appeared on the saline-treated VFs than the VFs treated with betamethasone. Inflammatory cell number showed significant difference between both VFs at 3 days (p = .037) and 7 days (p = .045). No significant different was found in epithelial thickness at 1 month between the betamethasone and saline groups. The collagen in the saline-treated VFs was significantly denser than that of the betamethasone-treated group (p = .037). There was also a significant increase in the level of hyaluronic acid (HA) in betamethasone-injected VFs in comparison to the saline-injected VFs (p = .006).

Conclusions

Based on this study, compound betamethasone can improve VF healing. Our findings suggest that VF injection with compound betamethasone helps to minimize scarring by increasing HA level and decreasing collagen density.

Comparative proteomic changes in rabbit vocal folds undergoing systemic dehydration and systemic rehydration

BACKGROUND

A considerable body of clinical evidence suggests that systemic dehydration can negatively affect voice production, leading to the common recommendation to rehydrate. Evidence for the corrective benefits of rehydration, however, is limited with mixed conclusions, and biological data on the underlying tissue changes with rehydration is lacking. In this study, we used a rabbit model (n = 24) of acute (5 days) water restriction-induced systemic dehydration with subsequent rehydration (3 days) to explore the protein-level changes underlying the molecular transition from euhydration to dehydration and following rehydration using LC-MS/MS protein quantification in the vocal folds. We show that 5-day water restriction led to an average 4.3% decrease in body weight with relative increases in anion gap, Cl-, creatinine, Na+, and relative decreases in BUN, iCa2+, K+, and tCO2 compared to control (euhydrated) animals. A total of 309 differentially regulated (p < 0.05) proteins were identified between the Control and Dehydration groups. We observed a noteworthy similarity between the Dehydration and Rehydration groups, both well differentiated from the Control group, highlighting the distinct timelines of resolution of the clinical symptoms of systemic dehydration and the underlying molecular changes.

SIGNIFICANCE

Voice disorders are a ubiquitous problem with considerable economic and psychological impact. Maintenance of proper hydration is commonly prescribed as a general vocal hygiene practice. There is evidence that dehydration negatively impacts phonation, but our understanding of the state of vocal folds in the context of systemic dehydration are limited, particular from a molecular perspective. Further, ours is a novel molecular study of the short-term impact of rehydration on the tissue. Given the relatively minimal difference in vocal fold proteomic profiles between the Dehydration and Rehydration groups, our data demonstrate a complex physiological response to acute systemic dehydration, and highlight the importance of considering persistent underlying molecular pathology despite the rapid resolution of clinical measures. This study sets a foundation for future research to confirm the nature of potential beneficial outcomes of clinical recommendations related to hydration.

Hsp47 acts as a bridge between NLRP3 inflammasome and hepatic stellate cells activation in arsenic-induced liver fibrosis

The activation of hepatic stellate cells (HSCs) is a key event during the progression of liver fibrosis (LF). We have previously indicated that NLRP3 inflammasome plays a crucial role in arsenic-induced HSCs activation. However, the mechanism of cascade responses between NLRP3 inflammasome and HSCs activation is unclear. Here, we showed that the transcription and protein level of Hsp47 was upregulated after 4μM arsenic treatment, both in vivo and in vitro. Additionally, arsenic-induced HSCs activation was remarkably alleviated by the interference of Hsp47. Furthermore, blockage of NLRP3 significantly mitigated the activation of the NLRP3 inflammasome and decreased the expression of Hsp47, thereby attenuating the arsenic-induced HSCs activation. However, the ablation of Hsp47 did not affect the activation of the NLRP3 inflammasome. Notably, the protein-protein interaction between NLRP3 and Hsp47 was observed both in vivo and in vitro, and the target amino acid sequences were further identified. In summary, the present study indicated that NaAsO₂ induced HSCs activation via the NLRP3 inflammasome-Hsp47 pathway. These findings provide direct evidence that Hsp47 may be a potential therapeutic target for arsenic-induced LF.

CyPA interacts with SERPINH1 to promote extracellular matrix production and inhibit epithelial-mesenchymal transition of trophoblast via enhancing TGF-β/Smad3 pathway in preeclampsia

We previously reported that cyclophilin A (CyPA) production is upregulated in preeclampsia (PE). Moreover, CyPA is known to induce PE-like features in pregnant mice and impair trophoblast invasiveness. In this study, we further illustrated the role of CyPA in PE. RNA-seq analysis, RT-qPCR, immunohistochemical (IHC) staining, and western blotting of mouse placentae revealed that CyPA increased the levels of extracellular matrix (ECM) proteins, such as collagen I and fibronectin, and activated the TGF-β/Smad3 signaling pathway. Additionally, CyPA inhibited the expression of genes involved in epithelial-mesenchymal transition (EMT) (e.g., E-cadherin, N-cadherin, and vimentin) in mouse placentae. We then constructed stable overexpressing and knock-down CyPA cell models (using HTR8/SVneo cells) to clarify the molecular mechanism. We found that CyPA regulated the levels of ECM-related proteins and the EMT process through the TGF-β/Smad3 pathway. We also identified SERPINH1 as a putative CyPA-binding protein, using liquid chromatography-electrospray mass spectrometry (LC-MS)/MS. SERPINH1 was found to be upregulated in the placentae of PE. Silencing SERPINH1 expression reversed the upregulation of ECM proteins and inhibition of the EMT process induced by the overexpression of CyPA. These findings revealed the functions of CyPA in the impaired invasiveness of trophoblasts in PE and indicated that CyPA and SERPINH1 may represent promising targets for the treatment of PE.

Current approaches to management of vocal fold scar

PURPOSE OF REVIEW

Vocal fold (VF) fibrosis remains an insoluble problem in most cases, with a severe impact on vocal quality and effort. This review examines current investigations and research strands that explore the understanding of VF wound healing and applied treatments for the management of VF scar.

RECENT FINDINGS

Recent work focused on VF fibrosis has examined wound healing in the glottis, fibrosis-modifying medication, and tissue engineering approaches that span cytokine and growth factor therapy, scaffold and cell delivery platforms, seeded scaffolds, conditioned media and stem cell therapy. Many show promise and may deliver improvements in the wound bed favouring less fibrogenic healing patterns, ultimately with the goal of preserving or restoring VF vibration. Further collaborative research is required that examines combined approaches, long term outcomes, better three-dimensional modelling of cell-cell interactions and delivery modalities for molecular therapies.

SUMMARY

VF fibrosis research continues to expand and explore a variety of mechanistic pathways in order to understand VF healing and identify novel and complementary targets for manipulation. Many different approaches show promise and may also offer synergistic benefits. Research continues to strive for healing that more closely resembles true VF architecture and function.

[Molecular laryngology : A new chapter in the understanding of laryngeal diseases]

BACKGROUND

Despite considerable advances in laryngological research, there is still a plethora of (benign) vocal fold pathologies that cannot be treated causally. This is due to the limited accessibility and sensitive microarchitecture of the vocal folds, which cannot be investigated at a cellular level. Consequently, current pathophysiological knowledge is frequently based on macroscopic findings. The impact of interventions is mainly evaluated endoscopically or via indirect diagnostic methods.

OBJECTIVE

The aim of this article is to discuss state-of-the-art biotechnological methods used in laryngological research, illustrated by practical examples.

RESULTS

In recent years, animal and in vitro experiments have significantly contributed to a continuous expansion of knowledge in this field, particularly regarding vocal fold inflammation and scar formation. Vocal fold fibroblasts, the most important cellular component of the lamina propria, can be accredited a central role in these processes.

CONCLUSION

Our knowledge regarding macroanatomy and macropathophysiology of several pathologies has increased considerably in recent years. In vitro trials have shown, e.g., that vocal fold fibroblasts in an inflammatory setting secrete less profibrotic and proinflammatory cytokines when exposed to vibration. Early vocal exercises after surgical interventions on the vocal folds may therefore promote better wound healing and consequently improved phonation. Research in molecular laryngology should create a solid basis of knowledge for subsequent clinical studies.

Bioinformatic Analysis of Key Genes and Pathways Related to Keloids

Background

The pathophysiology of keloids is complex, and the treatment for keloids is still an unmet medical need. Our study is aimed at identifying the hub genes among the differentially expressed genes (DEGs) between normal skin tissue and keloids and key pathways in the development of keloids.

Materials and Methods

We downloaded the GSE92566 and GSE90051 microarray data, which contain normal skin tissue and keloid gene expression data. GSE92566 was treated as a discovery dataset for summarizing the significantly DEGs, and GSE90051 served as a validation dataset. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes pathway, Reactome enrichment analysis, gene set enrichment analysis, and gene set variation analysis were performed for the key functions and pathways enriched in DEGs. Moreover, we also validated the hub genes identified from the protein-protein interaction network and predicted miRNA-hub gene interactions.

Results

117 downregulated DEGs and 204 upregulated DEGs in GSE92566 were identified. Extracellular and collagen-related pathways were prominent in upregulated DEGs, while the keratinization-related pathway was associated with downregulated DEGs. The hub genes included COL5A1, COL5A2, and SERPINH1, which were also validated in GSE90051.

Conclusion

This study identified several hub genes and provided insights for the underlying pathways and miRNA-hub gene interactions for keloid development through bioinformatic analysis of two microarray datasets. Additionally, our results would support the development of future therapeutic strategies.

Silencing Heat Shock Protein 47 (HSP47) in Fibrogenic Precision-Cut Lung Slices: A Surprising Lack of Effects on Fibrogenesis?

Idiopathic pulmonary fibrosis (IPF) is a chronic disease that is characterized by the excessive deposition of scar tissue in the lungs. As currently available treatments are unable to restore lung function in patients, there is an urgent medical need for more effective drugs. Developing such drugs, however, is challenging because IPF has a complex pathogenesis. Emerging evidence indicates that heat shock protein 47 (HSP47), which is encoded by the gene Serpinh1, may be a suitable therapeutic target as it is required for collagen synthesis. Pharmacological inhibition or knockdown of HSP47 could therefore be a promising approach to treat fibrosis. The objective of this study was to assess the therapeutic potential of Serpinh1-targeting small interfering RNA (siRNA) in fibrogenic precision-cut lung slices prepared from murine tissue. To enhance fibrogenesis, slices were cultured for up to 144 h with transforming growth factor β1. Self-deliverable siRNA was used to knockdown mRNA and protein expression, without affecting the viability and morphology of slices. After silencing HSP47, only the secretion of fibronectin was reduced while other aspects of fibrogenesis remained unaffected (e.g., myofibroblast differentiation as well as collagen secretion and deposition). These observations are surprising as others have shown that Serpinh1-targeting siRNA suppressed collagen deposition in animals. Further studies are therefore warranted to elucidate downstream effects on fibrosis upon silencing HSP47.

Mechanisms Underlying the Antifibrotic Potential of Estradiol for Vocal Fold Fibrosis

OBJECTIVES/HYPOTHESIS

Vocal fold fibrosis remains a significant clinical challenge. Estrogens, steroid hormones predominantly responsible for secondary sexual characteristics in women, have been shown to alter wound healing and limit fibrosis, but the effects on vocal fold fibrosis are unknown. We sought to elucidate the expression of estrogen receptors and the effects of estrogens on TGF-β1 signaling in rat vocal fold fibroblasts (VFFs).

STUDY DESIGN

In vitro.

METHODS

VFFs were isolated from 10-week-old, male Sprague-Dawley rats, and estrogen receptor alpha (ERα) and G protein-coupled receptor 30 (GPR30) were examined via immunostaining and quantitative polymerase chain reaction (qPCR). VFFs were treated with estradiol (E2, 10^-7 , 10^-8 or 10^-9  M) ± transforming growth factor beta 1 (TGF-β1, 10 ng/mL). ICI 182,780 (ICI, 10^-7  M) or G36 (10^-7  M) were employed as antagonists of ERα or GPR30, respectively. qPCR was employed to determine estrogen receptor-mediated effects of E2 on genes related to fibrosis.

RESULTS

ERα and GPR30 were expressed in VFFs at both the protein and the mRNA levels. E2 (10^-7  M) did not alter Smad3, Smad7, Acta2 mRNA, or extracellular matrix related genes. However, the combination of E2 (10^-8  M) and TGF-β1 significantly increased Smad7 (P = .03) and decreased Col1a1 (P = .04) compared to TGF-β1 alone; this response was negated by the combination of ICI and G36 (P = .009).

CONCLUSIONS

E2 regulated TGF-β1/Smad signaling via estrogen receptors in VFFs. These findings provide insight into potential mechanisms of estrogens on vocal fold injury with the goal of enhanced therapeutics for vocal fold fibrosis.

LEVEL OF EVIDENCE

NA Laryngoscope, 131:2285-2291, 2021.

In vitro mechanical vibration down-regulates pro-inflammatory and pro-fibrotic signaling in human vocal fold fibroblasts

INTRODUCTION

Voice rest following phonotrauma or phonosurgery has a considerable clinical impact, but clinical recommendations are inconsistent due to inconclusive data. As biopsies of the vocal folds (VF) for molecular biology studies in humans are unethical, we established a new in vitro model to explore the effects of vibration on human vocal fold fibroblasts (hVFF) in an inflammatory and normal state, which is based on previously published models.

METHODS

By using a phonomimetic bioreactor we were able to apply predefined vibrational stress patterns on hVFF cultured under inflammatory or normal conditions. Inflammatory and pro-fibrotic stimuli were induced by interleukin (IL)1β and transforming growth factor (TGF)β1, respectively. Mechanical stimulation was applied four hours daily, over a period of 72 hours. Outcome measurements comprised assessment of extracellular matrix (ECM)-related components, angiogenic factors, and inflammatory and fibrogenic markers on gene expression and protein levels.

RESULTS

Under inflammatory conditions, the inflammatory cytokine IL11, as well as the myofibroblast marker alpha smooth muscle actin (α-SMA) were significantly reduced when additional vibration was applied. The desirable anti-fibrotic ECM component hyaluronic acid was increased following cytokine treatment, but was not diminished following vibration.

CONCLUSION

Our experiments revealed the effect of vibrational stress on hVFF in an inflammatory state. Elevated levels of certain pro-inflammatory/pro-fibrotic factors could be mitigated by additional vibrational excitation in an in vitro setting. These findings corroborate clinical studies which recommend early voice activation following an acute event.

Phlorotannins ameliorate extracellular matrix production in human vocal fold fibroblasts and prevent vocal fold fibrosis via aerosol inhalation in a laser-induced fibrosis model

Vocal fold fibrosis is an abnormal condition characterized by unfavorable changes in the organization of the extracellular matrix in vocal fold lamina propria. To prevent and treat vocal fold fibrosis, a number of synthetic drugs, such as mitomycin C and the glucocorticoid family, are used after surgery, but these are known to have some side effects. Therefore, using both in vitro and in vivo studies, this study investigated whether phlorotannins extracted from Ecklonia cava have the potential to prevent vocal fold fibrosis with minimal side effects. The results show that phlorotannins suppressed both the expression of the fibrotic phenotypic marker and cell migration by inhibiting the activation of the mitogen-activated protein kinase (MAPK) and Smad2/3 signaling pathways in human vocal fold fibroblasts stimulated by transforming growth factor-β. Additionally, phlorotannins exhibited antifibrotic efficacy without an excessive inflammatory response in a laser-induced fibrosis rabbit model when delivered as an aerosol via inhalation. Based on these results, phlorotannins should be considered a promising candidate for use in the prevention of vocal fold fibrosis.

Unraveling the molecular pathobiology of vocal fold systemic dehydration using an in vivo rabbit model

Vocal folds are a viscoelastic multilayered structure responsible for voice production. Vocal fold epithelial damage may weaken the protection of deeper layers of lamina propria and thyroarytenoid muscle and impair voice production. Systemic dehydration can adversely affect vocal function by creating suboptimal biomechanical conditions for vocal fold vibration. However, the molecular pathobiology of systemically dehydrated vocal folds is poorly understood. We used an in vivo rabbit model to investigate the complete gene expression profile of systemically dehydrated vocal folds. The RNA-Seq based transcriptome revealed 203 differentially expressed (DE) vocal fold genes due to systemic dehydration. Interestingly, function enrichment analysis showed downregulation of genes involved in cell adhesion, cell junction, inflammation, and upregulation of genes involved in cell proliferation. RT-qPCR validation was performed for a subset of DE genes and confirmed the downregulation of DSG1, CDH3, NECTIN1, SDC1, S100A9, SPINK5, ECM1, IL1A, and IL36A genes. In addition, the upregulation of the transcription factor NR4A3 gene involved in epithelial cell proliferation was validated. Taken together, these results suggest an alteration of the vocal fold epithelial barrier independent of inflammation, which could indicate a disruption and remodeling of the epithelial barrier integrity. This transcriptome provides a first global picture of the molecular changes in vocal fold tissue in response to systemic dehydration. The alterations observed at the transcriptional level help to understand the pathobiology of dehydration in voice function and highlight the benefits of hydration in voice therapy.

The Role of Cytokines in Modulating Vocal Fold Fibrosis: A Contemporary Review

OBJECTIVES

Vocal fold (VF) scarring and laryngeal stenosis are a significant clinical challenge. Excessive scar formation causes low voice quality or even life-threatening obstructions. Cytokines are thought to modulate multiple steps of the establishment of VF fibrosis, but there is no systematic report regarding their role in modulating VF fibrosis. This review aims to investigate the role of cytokines in modulating vocal fold fibrosis.

STUDY DESIGN

Literature review.

METHODS

This review searched for all relevant peer publications in English for the period 2009 to 2019 in the PubMed database using search terms: "laryngeal stenosis," "vocal fold scarring," and "cytokines." A thorough investigation of the methods and results of the reviewed studies was performed.

RESULTS

Comprehensive research in various studies, including analyses of prostaglandin E2 (PGE2), granulocyte-macrophage colony-stimulating factor (GM-CSF), hepatocyte growth factor (HGF), basic fibroblast growth factor (bFGF), transforming growth factor-β3 (TGF-β3), and interleukin-10 (IL-10), supports cytokine therapy for VF scarring and laryngeal stenosis to some extent. A few clinical studies on this topic support the conclusion that HGF and bFGF can be selected as effective drugs, and no serious side effects were found.

CONCLUSIONS

This review describes the potential of cytokines for modulating the process of VF fibrogenesis, although cytokines are still an unproven treatment method. As no ideal drugs exist, cytokines may be considered the candidate treatment for preventing VF fibrogenesis. Laryngoscope, 131:139-145, 2021.

Heat Shock Protein 47 Maintains Cancer Cell Growth by Inhibiting the Unfolded Protein Response Transducer IRE1α

HSP47 is a collagen-specific protein chaperone expressed in fibroblasts, myofibroblasts, and stromal cells. HSP47 is also expressed in and involved in growth of cancer cells in which collagen levels are extremely low. However, its role in cancer remains largely unclear. Here, we showed that HSP47 maintains cancer cell growth via the unfolded protein response (UPR), the activation of which is well known to be induced by endoplasmic reticulum (ER) stress. We observed that HSP47 forms a complex with both the UPR transducer inositol-requiring enzyme 1α (IRE1α) and ER chaperone BiP in cancer cells. Moreover, HSP47 silencing triggered dissociation of BiP from IRE1α and IRE1α activation, followed by an increase in the intracellular level of reactive oxygen species (ROS). Increase in ROS induced accumulation of 4-hydroxy-2-nonenal-protein adducts and activated two UPR transducers, PKR-like ER kinase (PERK) and activating transcription factor 6α (ATF6α), resulting in impaired cancer cell growth. Our work indicates that HSP47 expressed in cancer cells relieves the ER stress arising from protein synthesis overload within these cells and tumor environments, such as stress induced by hypoxia, low glucose, and pH. We also propose that HSP47 has a biological role that is distinct from its normal function as a collagen-specific chaperone. IMPLICATIONS: HSP47 maintains cancer cell growth by inhibiting IRE1α.

A tissue-specific, injectable acellular gel for the treatment of chronic vocal fold scarring

Gel-based injectable biomaterials have significant potential for treating vocal fold defects such as scarring. An ideal injectable for vocal fold lamina propria restoration should mimic the microenvironment of the lamina propria to induce scarless wound healing and functional tissue regeneration. Most current synthetic or natural injectable biomaterials do not possess the same level of complex, tissue-specific constituents as the natural vocal fold lamina propria. In this study we present a newly-developed injectable gel fabricated from decellularized bovine vocal fold lamina propria. Blyscan assay and mass spectrometry indicated that the vocal fold-specific gel contained a large amount of sulfated glycosaminoglycans and over 250 proteins. Gene Ontology overrepresentation analysis revealed that the proteins in the gel dominantly promote antifibrotic biological process. In vivo study using a rabbit vocal fold injury model showed that the injectable gel significantly reduced collagen density and decreased tissue contraction of the lamina propria in vocal folds with chronic scarring. Furthermore, this acellular gel only elicited minimal humoral immune response after injection. Our findings suggested that the tissue-specific, injectable extracellular matrix gel could be a promising biomaterial for treating vocal fold scarring, even after the formation of mature scar. STATEMENT OF SIGNIFICANCE: Vocal fold lamina propria scarring remains among the foremost therapeutic challenges in the management of patients with voice disorders. Surgical excision of scar may cause secondary scarring and yield inconsistent results. The present study reports an extracellular matrix-derived biomaterial that demonstrated antifibrotic effect on chronic scarring in vocal fold lamina propria. Its injectability minimizes the invasiveness of the delivery procedure and the degree of mucosal violation. In this work we also describe a new methodology which can more accurately identify proteins from the complex mixture of an acellular extracellular matrix gel by excluding interfering peptides produced during the enzymatic digestion in gel fabrication.