Potential treatment for vocal fold scar with pirfenidone

Injectable Tissue Adhesive Microgel Composite Containing Antifibrotic Drug for Vocal Fold Scarring

Vocal fold (VF) scarring, a complex problem in laryngology, results from injury and inflammation of the layered architecture of the VFs. The resultant voice hoarseness, for which successful therapeutic options are currently limited, affects the patient's quality of life. A promising strategy to reverse this disorder is the use of antifibrotic drugs. The present study proposes a novel microbead-embedded injectable hydrogel that can sustain the release of the anti-fibrotic drug pirfenidone (PFD) for vocal fold scarring. Microbeads were developed using sodium alginate and gelatin, which were further embedded into a biomimetic and tissue adhesive gellan gum (GG) hydrogel. The microbead-embedded hydrogel exhibited improved injectability, viscoelasticity, tissue adhesiveness, degradability, and swelling compared to the hydrogel without beads. Additionally, the bead-embedded hydrogel could sustain the release of the PFD for a week. In vitro studies showed that the drug-loaded hydrogel could reduce the migration and proliferation of fibroblast cells in a dose-dependent manner. In summary, this study demonstrates the potential of a PFD-loaded injectable hydrogel with enhanced viscoelastic and tissue-adhesive properties for vocal fold scarring applications.

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.

Duration of Clinical Response After In-Office Steroid Injection for Vocal Fold Scar

OBJECTIVE

To assess the duration of clinical response after in-office vocal fold steroid injection (VFSI) for vocal fold (VF) scar.

METHODS

Demographic and clinical data for in-office VFSI occurring from 2017 to 2020 were collected. Two Speech-Language Pathologists (SLPs) used perceptual evaluation of voice and functional scales to evaluate blinded voice and laryngovideostroboscopy (LVS) samples collected pre- and post-injection across multiple timepoints.

RESULTS

Blinded SLP ratings were used for 30 individual VFs undergoing initial injection in 18 patients. Persistent improvement in voice past 6 months was seen in 57% of patients after VFSI. Multiple measures of voice and amplitude, percent vibrating tissue, and closed phase predominance significantly improved at various follow-up timepoints on average.

CONCLUSION

Accounting for patient heterogeneity and disease progression, in-office VFSI for VF scar is associated with sustained improvement in a subset of patients. Approximately half of patients can expect to experience a lasting improvement in voice. Future studies of larger scale are required to identify patient factors associated with long-term benefit.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:2333-2339, 2023.

Treatment of scarring central airway stenosis with pirfenidone: Case report

INTRODUCTION

Benign scarring central airway stenosis can be managed by high-pressure balloon dilatation, laser, surgery and stent implantation. The stenosis may have a high recurrence rate that necessitates repeated treatment. Pirfenidone (PFD) has anti-fibrosis effects and has been used in a variety of fibrosis diseases. Animal experiments suggested that PFD can prevent tracheal stenosis.

PATIENT CONCERNS

Patients with scarring central airway stenosis usually have chest tightness, cough and dyspnea.

DIAGNOSIS

Computed tomography scanning showed stenosis of the trachea and/or bronchus. Bronchoscopy revealed occlusion or stenosis of the trachea or bronchus.

INTERVENTIONS

The use of PFD in combination with other interventional management was reported to treat 2 cases of tracheobronchial stenosis after injury in this study. In the combined use of PFD and interventional management, PFD could help to alleviate tracheobronchial stenosis, prolong the time interval of bronchoscopic interventional treatment, and reduce medical costs.

OUTCOMES

The stenosis in the trachea and/or bronchus is relieved and the patients do not have any relevant symptoms.

Scarless Healing of Injured Vocal Folds Using an Injectable Hyaluronic Acid-Waterborne Polyurethane Hybrid Hydrogel to Tune Inflammation and Collagen Deposition

Vocal fold (VF) scarring results from injury to the unique layered structure and is one of the main reasons for long-lasting dysphonia. A minimally invasive procedure with injectable hydrogels is a promising method for therapy. However, current surgical techniques or standard injectable fillers do not yield satisfactory outcomes. In this work, an injectable hybrid hydrogel consisting of oxide hyaluronic acid and hydrazide-modified waterborne polyurethane emulsion was injected precisely into the injury site and cross-linked in situ by a dynamic hydrazone bond. The prepared hydrogel displays excellent injectability and self-healing ability, showing favorable biocompatibility and biodegradability to facilitate endogenous newborn cell migration and growth for tissue regeneration. With the aim of evaluating the antifibrosis and regeneration capacity of the hybrid hydrogel in the VF scarring model, the morphology and vibration characteristics of VFs, inflammatory response, and healing status were collected. The hybrid hydrogel can decrease the inflammation and increase the ratio of collagen III/collagen I to heal damaged scar-free tissue. Fascinatingly, the mucosal wave oscillations of healing VF by injecting the hybrid hydrogel were vibrated like the normal VF, achieving functional restoration. This work highlights the utility of hybrid hydrogels consisting of synthetic biodegradable waterborne polyurethane emulsions and natural hyaluronic acid as promising biomaterials for scarless healing of damaged VFs.

The Antiproliferative and Antifibrotic Effects of Cisplatin on Primary Human Vocal Fold Fibroblasts

OBJECTIVE

Vocal fold scarring and laryngeal stenosis are major clinical challenges. Current drugs do not efficiently reduce scarring. We examined the antiproliferative and antifibrotic effects of cisplatin on primary human vocal fold fibroblasts (HVFFs).

METHODS

HVFFs were cultured in vitro and identified by immunocytochemistry. The relative viability of HVFFs was analyzed by Cell Counting Kit-8 assays (CCK-8). The fibrogenic phenotype was induced by transforming growth factor-β1 (TGF-β1) and reversed by cisplatin as shown by immunocytochemistry. Real-time PCR and Western blotting assessed collagen III and I. Western blotting for Smad2, p-Smad2, Smad-3, p-Smad3 and caspase-3 were performed.

RESULTS

CCK-8 results showed that cisplatin decreased the relative viability of HVFFs, and Western blots revealed elevation of the apoptosis-related protein caspase-3 in HVFFs. Cisplatin treatment reduced α-smooth muscle actin staining intensity in the presence of TGF-β1. Real-time PCR revealed the downregulation of collagen III and I in cisplatin-treated HVFFs. The TGF-β1-induced increased fibrogenic protein levels were decreased by cisplatin. Reduced levels were detected at late time points.

CONCLUSIONS

Cisplatin induces antiproliferative and antifibrotic alterations in HVFFs. Cisplatin may prevent postoperative vocal fold scarring and laryngeal stenosis in patients treated with CO2 laser microsurgery and undergoing delayed wound healing.

Pirfenidone inhibits epithelial-mesenchymal transition in keloid keratinocytes

Background

Keloids are benign fibroproliferative skin lesions that are difficult to treat and become a lifetime predicament for patients. Several treatment modalities have been put forth, but as yet no satisfactory approach to the prevention or treatment of keloids has been identified. The process of epithelial-to-mesenchymal transition (EMT) has been implicated in keloid scarring, as keloid keratinocytes display an EMT-like phenotype. This study investigated the potential of pirfenidone, an antifibrotic agent, to counteract EMT-like alterations in keloid keratinocytes, including gene expression, cell migratory and proliferative functions.

Methods

Normal and keloid keratinocytes were isolated from discarded normal skin tissues and from resected keloid tissues, respectively. Cells were quiesced for 24 h without epidermal growth factor DS-Qi1MCDigital and were exposed to transforming growth factor-beta1 (TGF-β1; 10 ng/mL), with or without pirfenidone (400 μg/mL), for an additional 24 h. The effects of pirfenidone on cytotoxicity, cell migration, cell proliferation, and on expression of genes and proteins involved in EMT were assayed. Statistical significance was determined by two-way ANOVA using Sigma Plot.

Results

We found that pirfenidone did not elicit any cytotoxic effect at concentrations up to 1000 μg/mL. A statistically significant dose-dependent decrease in basal cell proliferation rate was noted in both normal and keloid keratinocytes when exposed to pirfenidone at concentrations ranging from 200 to 1000 μg/mL. Pirfenidone significantly decreased basal cell migration in both normal and keloid keratinocytes, but a significant decrease in TGF-β1-induced cell migration was seen only in keloid keratinocytes. Significant inhibition of the expression of TGF-β1-induced core EMT genes, namely hyaluronan synthase 2, vimentin, cadherin-11, and wingless-type MMTV integration site family, member 5A along with fibronectin-1, was observed in both normal and keloid keratinocytes treated with pirfenidone. In addition, the protein levels of vimentin and fibronectin were significantly reduced by pirfenidone (400 μg/mL) in both normal and keloid keratinocytes.

Conclusions

For the first time, this study shows the efficacy of pirfenidone in inhibiting the EMT-like phenotype in keratinocytes derived from keloids, suggesting that pirfenidone may counteract a critical contributor of keloid progression and recurrence.

Effect of pirfenidone injection on ferret vocal fold scars: A preliminary in vivo study

OBJECTIVES

This study examined the antifibrotic effect of pirfenidone (PFD), which has received regulatory approval in the United States and Japan for treatment of idiopathic pulmonary fibrosis, on the scarred ferret vocal fold (VF) in vivo.

METHODS

Eight male ferrets were divided into two groups: saline and PFD. All animals underwent unilateral scarring under anesthesia. The right VF was electrocauterized with ablation of the entire lamina propria. PFD (1.0 mg/mL) or saline injections into right-side scarred VFs were performed (under an operating microscope) 4 weeks later. After an additional 4 weeks, the larynges were harvested for histological analysis. Prior to harvesting, the ferrets were re-anesthetized, and the VFs were observed and recorded using a rigid video laryngoscope. We immunohistochemically evaluated the expression of collagen types I and III, alpha-smooth muscle actin (α-SMA), and fibronectin in the entire lamina propria. We compared the affected areas (calculated using ImageJ software) between the treated (right) and untreated (left) sides within the same animals and between groups.

RESULTS

Collagen type I (P = 0.0021) and α-SMA (P = 0.0021) expression levels were lower in the PFD group, but the collagen type III and fibronectin levels did not differ significantly between the two groups.

CONCLUSION

PFD injection into the scarred VF is a potentially promising novel antifibrotic treatment.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:726-731, 2020.

Pathophysiology of Fibrosis in the Vocal Fold: Current Research, Future Treatment Strategies, and Obstacles to Restoring Vocal Fold Pliability

Communication by voice depends on symmetrical vibrations within the vocal folds (VFs) and is indispensable for various occupations. VF scarring is one of the main reasons for permanent dysphonia and results from injury to the unique layered structure of the VFs. The increased collagen and decreased hyaluronic acid within VF scars lead to a loss of pliability of the VFs and significantly decreases their capacity to vibrate. As there is currently no definitive treatment for VF scarring, regenerative medicine and tissue engineering have become increasingly important research areas within otolaryngology. Several recent reviews have described the problem of VF scarring and various possible solutions, including tissue engineered cells and tissues, biomaterial implants, stem cells, growth factors, anti-inflammatory cytokines antifibrotic agents. Despite considerable research progress, these technical advances have not been established as routine clinical procedures. This review focuses on emerging techniques for restoring VF pliability using various approaches. We discuss our studies on interactions among adipose-derived stem/stromal cells, antifibrotic agents, and VF fibroblasts using an in vitro model. We also identify some obstacles to advances in research.