Dual growth factor-immobilized bioactive injection material for enhanced treatment of glottal insufficiency

Precision-Targeted Injection Laryngoplasty and Longitudinal Biomaterial Effects Evaluation Using High-resolution Ultrasonography in a Rat Model

OBJECTIVE

Current laryngeal injection models rely on the transoral route and are suboptimal due to limited view, narrowed working space, and the need to sacrifice animals for investigation of the injectables. In the present study, a novel surgical model for laryngeal intervention therapy utilizing an ultra-high frequency ultrasound imaging system was proposed. Based on this system, we developed a systemic evaluation approach, from guidance of the injection process, documentation of the injection site of the material, to in vivo longitudinal follow-up on the augmentation and medialization effect by analyzing the ultrasonography data.

STUDY DESIGN

In vivo animal study.

SETTING

Academic institution.

METHODS

Injection laryngoplasty with hyaluronic acid under ultrasonography guidance was performed on Sprague-Dawley rats one week after induced unilateral vocal paralysis. Ultrasonography was performed at preinjection, immediately postinjection, on Day 2, Day 7 and then weekly for 4 weeks to obtain measurements, including the glottic area, angle between bilateral folds, and vocal fold width ratio. Laryngoscopic and histologic studies were also performed.

RESULTS

Unilateral injections to the paralyzed fold were successfully performed as demonstrated by ultrasonographic, laryngoscopic, and histologic studies. The width ratio was significantly increased after injection for 4 weeks, while the glottic airway area was unchanged.

CONCLUSION

Here, a novel surgical model for laryngeal injection utilizing ultrasonography in rats was established. In addition to providing visual guidance for precise localization of the injection, robust documentation of the treatment effect was also demonstrated. This methodology could be beneficial for screening therapeutic agents for treatment of glottic insufficiency.

Heparin-Functionalized Bioactive Glass to Harvest Endogenous Growth Factors for Pulp Regeneration

Pulp and periapical diseases can lead to the cessation of tooth development, resulting in compromised tooth structure and functions. Despite numerous efforts to induce pulp regeneration, effective strategies are still lacking. Growth factors (GFs) hold considerable promise in pulp regeneration due to their diverse cellular regulatory properties. However, the limited half-lives and susceptibility to degradation of exogenous GFs necessitate the administration of supra-physiological doses, leading to undesirable side effects. In this research, a heparin-functionalized bioactive glass (CaO-P2O5-SiO2-Heparin, abbreviated as PSC-Heparin) with strong bioactivity and a stable neutral pH is developed as a promising candidate to addressing challenges in pulp regeneration. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis reveal the successful synthesis of PSC-Heparin. Scanning electron microscopy and X-ray diffraction show the hydroxyapatite formation can be observed on the surface of PSC-Heparin after soaking in simulated body fluid for 12 h. PSC-Heparin is capable of harvesting various endogenous GFs and sustainably releasing them over an extended duration by the enzyme-linked immunosorbent assay. Cytological experiments show that developed PSC-Heparin can facilitate the adhesion, migration, proliferation, and odontogenic differentiation of stem cells from apical papillae. Notably, the histological analysis of subcutaneous implantation in nude mice demonstrates PSC-Heparin is capable of promoting the odontoblast-like layers and pulp-dentin complex formation without the addition of exogenous GFs, which is vital for clinical applications. This work highlights an effective strategy of harvesting endogenous GFs and avoiding the involvement of exogenous GFs to achieve pulp-dentin complex regeneration, which may open a new horizon for regenerative endodontic therapy.

A self-fused hydrogel for the treatment of glottic insufficiency through outstanding durability, extracellular matrix-inducing bioactivity and function preservation

Injection laryngoplasty with biomaterials is an effective technique to treat glottic insufficiency. However, the inadequate durability, deficient pro-secretion of extracellular matrix (ECM) and poor functional preservation of current biomaterials have yielded an unsatisfactory therapeutic effect. Herein, a self-fusing bioactive hydrogel comprising modified carboxymethyl chitosan and sodium alginate is developed through a dual-crosslinking mechanism (photo-triggered and dynamic covalent bonds). Owing to its characteristic networks, the synergistic effect of the hydrogel for vocal folds (VFs) vibration and phonation is adequately demonstrated. Notably, owing to its inherent bioactivity of polysaccharides, the hydrogel could significantly enhance the secretion of major components (type I/III collagen and elastin) in the lamina propria of the VFs both in vivo and in vitro. In a rabbit model for glottic insufficiency, the optimized hydrogel (C₁A₁) has demonstrated a durability far superior to that of the commercially made hyaluronic acid (HA) Gel. More importantly, owing to the ECM-inducing bioactivity, the physiological functions of the VFs treated with the C₁A₁ hydrogel also outperformed that of the HA Gel, and were similar to those of the normal VFs. Taken together, through a simple-yet-effective strategy, the novel hydrogel has demonstrated outstanding durability, ECM-inducing bioactivity and physiological function preservation, therefore has an appealing clinical value for treating glottic insufficiency.

Tissue Engineering as a Promising Treatment for Glottic Insufficiency: A Review on Biomolecules and Cell-Laden Hydrogel

Glottic insufficiency is widespread in the elderly population and occurs as a result of secondary damage or systemic disease. Tissue engineering is a viable treatment for glottic insufficiency since it aims to restore damaged nerve tissue and revitalize aging muscle. After injection into the biological system, injectable biomaterial delivers cost- and time-effectiveness while acting as a protective shield for cells and biomolecules. This article focuses on injectable biomaterials that transport cells and biomolecules in regenerated tissue, particularly adipose, muscle, and nerve tissue. We propose Wharton's Jelly mesenchymal stem cells (WJMSCs), induced pluripotent stem cells (IP-SCs), basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), insulin growth factor-1 (IGF-1) and extracellular vesicle (EV) as potential cells and macromolecules to be included into biomaterials, with some particular testing to support them as a promising translational medicine for vocal fold regeneration.

The Regenerative Effects of c-Met Agonistic Antibodies in Vocal Fold Atrophy

Background: Atrophy of the vocal folds and the accompanying glottic insufficiency affect the quality of life. Although growth factors have been used to treat muscle atrophy, their effectiveness is limited by their short half-life. Methods: In total, 15 rabbits and 24 rats were used for the study. The right recurrent laryngeal nerves of all animals were transected. One month following nerve transection, PBS (PBS group), rHGF (HGF group), or a c-Met agonistic antibody (c-Met group) was injected into the paralyzed vocal folds. The larynges of the rabbits were harvested from each group for histologic examination and subjected to PCR analysis. Results: Cross-sectional areas (CSAs) of thyroarytenoid muscles were evaluated. The c-Met group had increased CSAs compared to the PBS and HGF groups, but there were no significant differences compared to normal controls. The expression levels of myogenesis-related genes were evaluated three weeks after the injection. The expression levels of myosin heavy chain IIa were significantly increased in the PBS group, while the expression levels of MyoD were increased in the c-Met group. Conclusions: The c-Met agonistic antibody showed promise for promoting muscle regeneration in a vocal fold palsy model.

Red Blood Cell Membrane-Camouflaged PLGA Nanoparticles Loaded With Basic Fibroblast Growth Factor for Attenuating Sepsis-Induced Cardiac Injury

Cardiac injury is recognized as a major contributor to septic shock and a major component of the multiple organ dysfunction associated with sepsis. Emerging evidence shows that regulation of the intramyocardial oxidative stress and inflammatory response has a promising prospect. Basic fibroblast growth factor (bFGF) exhibits anti-inflammatory and antioxidant properties. In this study, red blood cell membrane-camouflaged poly (lactide-co-glycolide) nanoparticles were synthesized to deliver bFGF (bFGF-RBC/NP) for sepsis-induced cardiac injury. The in vitro experiments revealed that bFGF-RBC/NP could protect cardiomyocytes from oxidative and inflammatory damage. In addition, the antioxidant and anti-inflammatory properties of bFGF-RBC/NP against cardiac injury were validated using data from in vivo experiments. Collectively, our study used bFGF for the treatment of sepsis-induced cardiac injury and confirmed that bFGF-RBC/NP has therapeutic benefits in the treatment of myocardial dysfunction. This study provides a novel strategy for preventing and treating cardiac injury in sepsis.

Injection laryngoplasty of human adipose-derived stem cell spheroids with hyaluronic acid-based hydrogel improves the morphological and functional characteristics of geriatric larynx

Aim

As the geriatric population increased, the need of treatment for laryngeal atrophy and dysfunction increased. This study was performed to evaluate the effects of injection of human adipose-derived stem cell (hASC) spheroid-loaded catechol-conjugated hyaluronic acid (HA-CA) hydrogel on therapeutic rejuvenation of the geriatric larynx.

Methods

Stem cell spheroids with hyaluronic acid-based hydrogel were injected into the laryngeal muscles of 18-month-old Sprague–Dawley rats. The effects of hASC spheroids were examined in the following four groups: SHAM, injected with PBS; GEL, injected with HA-CA hydrogel; MONO, injected with single hASCs in HA-CA hydrogel; and SP, injected with hASCs spheroids in HA-CA hydrogel. The rejuvenation efficacy in geriatric laryngeal muscle tissues at 12 weeks postinjection was evaluated and compared by histology, immunofluorescence staining, and functionality analysis.

Results

Total myofiber cross-sectional area and myofiber number/density, evaluated by detection of myosin heavy chain with antibodies against laminin and fast myosin heavy chain, were significantly higher in the SP group than in the other groups. The lamina propria of the larynx was evaluated by alcian blue staining, which showed that the HA was increased significantly in the SP group compared to the other groups. In functional analysis, the glottal gap area was significantly reduced in the SP group compared to the other groups. The phase difference in the vocal fold during vibration was also smaller in the SP group than in the other groups, but the difference did not reach statistical significance.

Conclusion

Injection of hASC spheroids with hyaluronic acid-based hydrogel improves the morphological and functional characteristics of geriatric larynx.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40824-022-00261-x.

Rehabilitation Therapy for Vocal Fold Paralysis Caused by Lung Cancer: A Case Report

OBJECTIVE

Unilateral vocal fold paralysis (UVFP) can be caused by iatrogenic injury or tumor-induced damage to the recurrent laryngeal nerve. Studies of comprehensive rehabilitation therapies for patients suffering from severe UVFP are limited. The purpose of this case report is to describe an improvement in complete aphonia after comprehensive rehabilitation therapies in a patient with severe UVFP due to a lung tumor.

METHODS

An 81-year-old woman with a history of bronchial adenoma had complete aphonia due to compression of the left recurrent laryngeal nerve by the tumor. Dynamic fibrolaryngoscope revealed paralysis of the left vocal fold. The patient was treated with interferential current therapy, vocal training, and kinesiology taping. Indicators of voice recovery were scored according to the grade, roughness, breathiness, asthenia, strain scale, and the voice handicap index.

RESULTS

After 10 days of comprehensive rehabilitation treatment, the patient recovered from complete aphonia to normal communication. The hoarseness and breathiness of patient were significantly improved. In addition, the grade, roughness, breathiness, asthenia, strain, and the voice handicap index scores changed from severe to mild or absent.

CONCLUSION

This case provided a novel comprehensive treatment for a patient with UVFP, which was safe, cost-effective, and easy to implement in clinic.