Autologous fibroblasts for vocal scars and age-related atrophy: A randomized clinical trial

Glottic insufficiency caused by vocal fold atrophy with or without sulcus: systematic review of outcome measurements

PURPOSE

Identifying outcome measurements instruments (OMIs) to evaluate treatment efficacy in patients with vocal fold atrophy and/or sulcus.

METHODS

Systematic review of records published before March 2021 by searching Pubmed and EMBASE. Included studies reported on adults (> 18 year) with dysphonia caused by glottic insufficiency due to vocal fold atrophy with or without sulcus, who were enrolled into a randomized controlled trial, a non-randomized controlled trial, a case-controlled study or a cohort study. All included studies described an intervention with at least one outcome measurement.

RESULTS

A total of 5456 studies were identified. After removing duplicates, screening title and abstract and full text screening of selected records, 34 publications were included in final analysis. From these 50 separate OMIs were recorded and categorized according to the ELS protocol by DeJonckere et al. (Eur Arch Otorhinolaryngol 258: 77-82, 2001). With most OMIs being used in multiple studies the total number of OMIs reported was 265. Nineteen (19) individual OMIs accounted for 80% of reports. The most frequently used OMIs according to category were: VHI and VHI-10 (subjective evaluation); G of GRBAS (perceptual evaluation); F0, Jitter and Shimmer (acoustic evaluation); MPT and MFR (aerodynamic evaluation) and glottic closure and mucosal wave (endoscopic evaluation). Of these OMIs VHI had a high percentage of significance of 90%.

CONCLUSION

This systematic review identifies the most used OMIs in patients with glottic incompetency due to vocal fold atrophy and/or sulcus as a step toward defining a Core Outcome Set (COS) for this population.

PROSPERO REGISTRATION

238274.

Immunocytochemistry assessment of vocal fold regeneration after cell-based implant in rabbits

Objective

Cell-based outer vocal fold replacement (COVR) offers a potential treatment for severe vocal fold scarring or cancer reconstruction. Previous work in rabbits using human adipose-derived stem cells (ASC) in fibrin suggested that a hybrid structure emerged within 2 months, containing both implanted and host cells. This project uses immunocytochemistry to better define the phenotypic fate of implanted cells and features of the extracellular environment.

Methods

Immunocytochemistry was performed on sections collected from rabbits 2 months after COVR implantation or scar surgery. Cellular targets included human leukocyte antigen (HLA), CD31, and smooth muscle actin (SMA).

Results

HLA was present in all implanted sections and was used to identify human cells. In adjacent sections, HLA-positive cells were identified expressing CD31. SMA was not identified in the same cells as HLA. These markers were also present in injured vocal folds not receiving COVR. SMA protein content did not differ according to treatment.

Conclusions

Implanted human ASC persist in rabbit vocal folds. Some appear to express CD31, an endothelial marker. Smooth muscle actin, a marker of myofibroblast phenotype, was present in all sections regardless of treatment, and was not identified in hASC. Host cells also infiltrate the structure, producing a hybrid host-graft vocal fold.

High-Resolution Profiling of Human Vocal Fold Cellular Landscapes With Single-Nuclei RNA Sequencing

INTRODUCTION

The function of the vocal folds (VFs) is determined by the phenotype, abundance, and distribution of differentiated cells within specific microenvironments. Identifying this histologic framework is crucial in understanding laryngeal disease. A paucity of studies investigating VF cellular heterogeneity has been undertaken. Here, we examined the cellular landscape of human VFs by utilizing single-nuclei RNA-sequencing.

METHODS

Normal true VF tissue was excised from five patients undergoing pitch elevation surgery. Tissue was snap frozen in liquid nitrogen and subjected to cellular digestion and nuclear extraction. Nuclei were processed for single-nucleus sequencing using the 10X Genomics Chromium platform. Sequencing reads were assembled using cellranger and analyzed with the scanpy package in python.

RESULTS

RNA sequencing revealed 18 global cell clusters. While many were of epithelial origin, expected cell types, such as fibroblasts, immune cells, muscle cells, and endothelial cells were present. Subcluster analysis defined unique epithelial, immune, and fibroblast subpopulations.

CONCLUSION

This study evaluated the cellular heterogeneity of normal human VFs by utilizing single-nuclei RNA-sequencing. With further confirmation through additional spatial sequencing and microscopic imaging, a novel cellular map of the VFs may provide insight into new cellular targets for VF disease.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:3193-3200, 2024.

Vocal fold fibroblasts and exposure to vibration in vitro: Does sex matter?

Studies have shown that certain vocal fold pathologies are more common in one sex than the other. This is often explained by differences in the composition of the lamina propria and anatomical differences between female and male vocal folds, resulting in e.g. different fundamental frequencies. Here, we investigated a potential sex-specific voice frequency effect in an in vitro setting using vocal fold fibroblasts from one male and one female donor with and without cigarette smoke extract (CSE) addition. After exposure to either male or female vibration frequency with or without CSE, cells and supernatants were harvested. Gene and protein analysis were performed by means of qPCR, western blot, ELISA and Luminex. We found that exposure of cells to both male and female vibration pattern did not elicit significant changes in the expression of extracellular matrix-, inflammation-, and fibrosis-related genes, compared to control cells. The addition of CSE to vibration downregulated the gene expression of COL1A1 in cells exposed to the female vibration pattern, as well as induced MMP1 and PTGS2 in cells exposed to both female and male vibration pattern. The protein expression of MMP1 and COX2 was found to be significantly upregulated only in cells exposed to CSE and female vibration pattern. To conclude, different vibration patterns alone did not cause different responses of the cells. However, the female vibration pattern in combination with CSE had a tendency to elicit/maintain more pro-inflammatory responses in cells than the male vibration pattern.

Evaluating Interventions for Sulcus Vocalis or Vocal Fold Scar: A Systematic Review and Meta-analysis

BACKGROUND

Sulcus vocalis reflects varying degrees of vocal cord lamina propria (LP) damage. Many interventions have been discussed in the literature for addressing sulcus vocalis, but there is no universally accepted gold standard for its management.

AIM

We aim in our study to collectively evaluate the effectiveness of different relevant interventions in the literature used for sulcus vocalis or vocal fold scar.

METHODS

We searched five electronic databases to collect all relevant studies. Records were screened for eligibility. Data were extracted from the included studies independently. Our continuous outcomes were pooled in our single-arm meta-analysis as mean change (MC) and with 95% confidence interval (CI).

RESULTS

Our systematic review and meta-analysis included 43 studies encompassing 1302 patients. The jitter parameter indicated that laser degeneration and LP regeneration/scar degradation led to the highest improvements compared to their baseline, with pooled MC of -0.897 and -0.893, respectively. Graft interposition showed a MC of -0.848, while medialization and dissection had less pronounced changes at -0.200. Shimmer parameter results were similar, with medialization and laser degeneration leading to MC of -2.129 and -2.123, while LP regeneration/scar degradation and graft interposition showed smaller changes MC -1.530 and -1.217. For the noise-to-harmonic ratio (NHR) parameter, LP regeneration/scar degradation demonstrated MC = -0.028. In aerodynamics outcomes, graft interposition and LP regeneration/scar degradation showed the highest MCs in mean phonatory time (MPT) (4.214 and 3.467, respectively). Endoscopic outcomes for mucosal wave showed high improvements in medialization and graft interposition (MC = 10.40 and 10.18, respectively). Perceptual outcomes favored graft interposition in various parameters, while laser degeneration performed well in most categories. Graft interposition and LP regeneration/scar degradation had a high voice handicap index (VHI) (MC = -27.195 and -19.269, respectively).

CONCLUSION

Laser degeneration and LP regeneration/scar degradation were particularly effective in improving acoustic parameters. In aerodynamics, graft interposition and LP regeneration/scar degradation improved vocal efficiency compared to their baselines. Medialization and laser degeneration had the largest impact compared to their baseline on shimmer and MPT. Endoscopic assessments showed that medialization and graft interposition had high improvement in mucosal waves, and perceptual outcomes were generally high with graft interposition and laser degeneration.

Treatments for Age-related Vocal Atrophy: A Systematic Review

OBJECTIVE

Age-related vocal atrophy (ARVA) can dramatically affect voice, communication, and quality of life. The objectives of this systematic review were to (1) determine whether treatments for ARVA were superior to controls (2) compare the relative efficacy of procedural and behavioral treatments (3) review the various types of outcome measures, and (4) evaluate the quality of studies.

REVIEW METHODS

The literature was searched using strategies designed by a medical librarian (2/18/21, updated 3/9/22). Studies investigating treatments for bilateral vocal atrophy were included. Studies involving unilateral atrophy, presbyphonia (without endoscopic findings), or an absent comparator group were excluded. The Preferred Reporting Items for Systematic Reviews and Meta-analyses checklist was used to guide this study.

RESULTS

After applying the inclusion/exclusion criteria, 8 articles remained, including 4 randomized trials and 4 cohort studies, and a narrative synthesis was performed. Surgical and behavioral treatments for ARVA appeared to be superior to control groups, based on specific outcome measures. However, the superiority of these treatments over controls was not uniformly observed across multiple outcome measures. When comparing different treatments, superiority could not be established based on the quality and completeness of the studies included in the systematic review. Outcome measures also varied between individual studies. Finally, the risk of bias was analyzed and scored. Consistent point deductions among reviewed studies were noted.

CONCLUSIONS

When comparing treatments for ARVA. Surgery and voice therapy were both superior to control groups based on specific outcome measures from different domains. Superiority of one treatment could not be established.

LEVEL OF EVIDENCE

N/A Laryngoscope, 133:2846-2855, 2023.

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.

Antifibrotic effects of Quercetin on TGF-β1-induced vocal fold fibroblasts

OBJECTIVE

To investigate the effects of Quercetin on vocal fold fibroblasts induced by TGF-β1 and vocal fold injury.

METHODS

The effects of Quercetin on collagen type I (COL-I), collagen type III (COL-III), and fibronectin (FN) expressions in transforming growth factor-β1 (TGF-β1)-induced human vocal fold fibroblasts were examined by the quantitative reverse transcription-polymerase chain reaction and the enzyme-linked immunosorbent assay. The Cell Counting Kit-8 was used to assess the influence of Quercetin on cell proliferation. A rat vocal fold injury model was developed. These rats were divided into a control group, a model group, and a Quercetin group. Pathorphological observations from Hematoxylin-eosin staining, the density of fibroblasts, and hypertrophic index were compared among the three groups.

RESULTS

Compared with cells untreated with TGF-β1, the mRNA and protein expression levels of COL-I, COL-II, and FN and proliferation ability in TGF-β1-induced human vocal fold fibroblasts were increased (all P<0.05). Compared with human vocal fold fibroblasts induced by TGF-β1, the mRNA and protein expression levels of COL-I, COL-II, and FN and proliferation ability in TGF-β1-induced human vocal fold fibroblasts following Quercetin stimulation were decreased (all P<0.05). There were no statistical differences between human vocal fold fibroblasts treated with or without Quercetin regarding cell proliferation and COL-I, COL-II, and FN expressions. Compared with the model group, Quercetin suppressed the fibrosis of the vocal fold following injury and the protein levels of COL-I, COL-II, and FN in tissue samples (all P<0.001). The density of fibroblasts and hypertrophic index in the vocal fold scar from the Quercetin group were lower than those in the model group (all P<0.05).

CONCLUSIONS

Quercetin inhibited TGF-β1-induced fibrotic changes and proliferation in human vocal fold fibroblasts and had an antifibrotic effect in vocal fold after injuries.

A xenograft study of human adipose stromal cell-based vocal fold mucosal replacement in rabbits

Objectives

Vocal fold (VF) scarring, manifested by increased collagen, decreased glycosaminoglycans (GAGs), and disrupted elastic fibers, remains a negative consequence of VF injury or resection. The objective of this study is to compare four reconstructive options after Vf mucosal resection in rabbits. A Cell-Based Outer Vocal fold Replacement (COVR) using human adipose-derived mesenchymal stromal cells (hASCs) in fibrin scaffold is directly compared with a decellularized scaffold implant, hASC injection, and resection alone without reconstruction. The primary hypothesis is that the cells-in-scaffold construct better reconstitutes the VF structure than either cells or scaffold alone, or than healing by secondary intention.

Methods

A total of49 rabbits received bilateral VF cordectomy, followed by either COVR implant, decellularized scaffold implant, hASC injection, or no reconstruction (injured control group). Larynges were harvested after 6 weeks.

Results

Histology demonstrated greater lamina propria thickness, less collagen deposition, and more GAGs in COVR animals versus all other treatment groups. Evidence of persistent human cells was found in about half of the cell-treated animals. RNA levels of fibrosis pathway and macrophage phenotype markers were statistically unchanged among treatment groups at 6 weeks.

Conclusion

These data support the efficacy of COVR implantation in restoring VF microstructure in rabbits. The intact COVR was required; isolated components of decellularized scaffold or injected hASC still produced histologic scarring. We propose that the unique bilayered cell structure within fibrin enables controlled matrix remodeling to minimize wound contraction and fibrosis, and to promote GAG deposition.

Level of Evidence

Basic science study.

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.

A Systematic Review on Surgical Treatments for Sulcus Vocalis and Vocal Fold Scar

OBJECTIVES/HYPOTHESIS

Vocal fold sulcus and scars are benign vocal fold lesions that present as a challenge to the laryngologist. A number of different surgical techniques have been proposed, aiming at restoring the lamina propria (LP), closing the glottal gap, or both. This study aimed to provide a systematic review of surgical treatment for sulcus and scar and to propose a new classification for these techniques.

STUDY DESIGN

A literature search using MEDLINE and Google Scholar through August 2020.

METHODS

Data on study design were retrieved and outcomes were classified as acoustic, aerodynamic, self-reported, perceptual, and stroboscopic. Methodological quality was assessed using the MINORs criteria. Each technique was classified as direct, indirect, or combined.

RESULTS

Our search included 31 studies with a total of 617 patients. Direct techniques included dissection, graft interposition, or LP regeneration/scar degradation while indirect techniques aimed for glottal gap closure. Only one article performed a comparison between different types of techniques and only eight studied the five types of outcomes. No superiority of any technique was noted in our analysis. Self-reported outcomes were the most frequently improved.

CONCLUSIONS

There seems to not exist a one-fits-all treatment for this clinical picture and no clear decision-making pattern. A recent trend toward sequential approaches, starting with less invasive procedures, can be observed. Laryngoscope, 2021.

Advances in regenerative medicine for otolaryngology/head and neck surgery

Head and neck structures govern the vital functions of breathing and swallowing. Additionally, these structures facilitate our sense of self through vocal communication, hearing, facial animation, and physical appearance. Loss of these functions can lead to loss of life or greatly affect quality of life. Regenerative medicine is a rapidly developing field that aims to repair or replace damaged cells, tissues, and organs. Although the field is largely in its nascence, regenerative medicine holds promise for improving on conventional treatments for head and neck disorders or providing therapies where no current standard exists. This review presents milestones in the research of regenerative medicine in head and neck surgery.