Epidermal growth factor mediated healing in stem cell-derived vocal fold mucosa

Prospective Outcomes After Serial Platelet-Rich Plasma (PRP) Injection in Vocal Fold Scar and Sulcus

OBJECTIVE

Vocal fold scar and sulcus pose significant treatment challenges with no current optimal treatment. Platelet-rich plasma (PRP), an autologous concentration of growth factors, holds promise for regenerating the superficial lamina propria. This study aims to evaluate the potential benefits of serial PRP injections on mucosal wave restoration and vocal function.

METHODS

In a prospective clinical trial across two institutions, patients with vocal fold scar underwent four serial PRP injections, one month apart. Blinded independent laryngologists and expert listeners used pretreatment and one-month post-fourth injection videostroboscopy and CAPE-V assessments to evaluate mucosal wave and voice quality changes, respectively. Additionally, patient reported outcome measures (PROMs) were evaluated.

RESULTS

In the study, 15 patients received 55 PRP injections without adverse effects. Eight patients (53.3%) had mild, three patients (20%) had moderate, and four patients (26.7%) had severe scar. There was an average reduction of 8.7 points in post-treatment VHI-10 scores (p = 0.007). The raters observed an improvement in post-treatment voice in 73.4% of cases, and CAPE-V scores showed a reduction of 18.8 points on average (p = 0.036). The videostroboscopic VALI ratings showed an improvement in mucosal wave rating from 2.0 to 4.0. On average, the raters perceived the post-PRP exams to be better in 56.7% of cases.

CONCLUSIONS

PRP has been validated as a safe autologous option for treatment of vocal fold scar. While results for mucosal wave and voice quality varied, there was a consistent improvement in PROMs.

LEVEL OF EVIDENCE

Level 3: Prospective cohort study, with blinded analysis Laryngoscope, 2024.

Introducing a new type of alternative laryngeal mucosa model

Research of human vocal fold (VF) biology is hampered by several factors. The sensitive microstructure of the VF mucosa is one of them and limits the in vivo research, as biopsies carry a very high risk of scarring. A laryngeal organotypic model consisting of VF epithelial cells and VF fibroblasts (VFF) may overcome some of these limitations. In contrast to human VFF, which are available in several forms, availability of VF epithelial cells is scarce. Buccal mucosa might be a good alternative source for epithelial cells, as it is easily accessible, and biopsies heal without scarring. For this project, we thus generated alternative constructs consisting of immortalized human VF fibroblasts and primary human buccal epithelial cells. The constructs (n = 3) were compared to native laryngeal mucosa at the histological and proteomic level. The engineered constructs reassembled into a mucosa-like structure after a cultivation period of 35 days. Immunohistochemical staining confirmed a multi-layered stratified epithelium, a collagen type IV positive barrier-like structure resembling the basement membrane, and an underlying layer containing VFF. Proteomic analysis resulted in a total number of 1961 identified and quantified proteins. Of these, 83.8% were detected in both native VF and constructs, with only 53 proteins having significantly different abundance. 15.3% of detected proteins were identified in native VF mucosa only, most likely due to endothelial, immune and muscle cells within the VF samples, while 0.9% were found only in the constructs. Based on easily available cell sources, we demonstrate that our laryngeal mucosa model shares many characteristics with native VF mucosa. It provides an alternative and reproducible in vitro model and offers many research opportunities ranging from the study of VF biology to the testing of interventions (e.g. drug testing).

Lack of Association between Epidermal Growth Factor or Its Receptor and Reflux Esophagitis, Barrett’s Esophagus, and Esophageal Adenocarcinoma: A Case-Control Study

The epidermal growth factor (EGF) and its receptor (EGFR) gene-gene interactions were shown to increase the susceptibility to esophageal cancer. However, the role of the EGF/EGFR pathway in the development of gastroesophageal reflux disease (GERD) and its complications (reflux esophagitis (RE), Barrett's esophagus (BE), and esophageal adenocarcinoma (EAC)) remains unclear. This association study is aimed at investigating functional EGF and EGFR gene polymorphisms, their mRNA expression in esophageal tissues, and EGF plasma levels in relation to RE, BE, and EAC development in the Central European population. 301 patients with RE/BE/EAC (cases) as well as 98 patients with nonerosive reflux disease (NERD) and 8 healthy individuals (controls) were genotyped for +61 A>G EGF (rs4444903) and +142285 G>A EGFR (rs2227983) polymorphisms using the TaqMan quantitative polymerase chain reaction (qPCR). In random subgroups, the EGF and EGFR mRNA expressions were analyzed by reverse transcription qPCR in esophageal tissue with and without endoscopically visible pathological changes; and the EGF plasma levels were determined by enzyme-linked immunosorbent assay. None of the genotyped SNPs nor EGF-EGFR genotype interactions were associated with RE, BE, or EAC development (p > 0.05). Moreover, mRNA expression of neither EGF nor EGFR differed between samples of the esophageal tissue with and without endoscopically visible pathology (p > 0.05) nor between samples from patients with different diagnoses, i.e., RE, BE, or EAC (p > 0.05). Nevertheless, the lower EGF mRNA expression in carriers of combined genotypes AA +61 EGF (rs4444903) and GG +142285 EGFR (rs2227983; p < 0.05) suggests a possible direct/indirect effect of EGF-EGFR gene interactions on EGF gene expression. In conclusion, EGF and EGFR gene variants and their mRNA/protein expression were not associated with RE, BE or EAC development in the Central European population.

Descriptive proteomics of paired human vocal fold and buccal mucosa tissue

The vast majority of voice disorders is associated with changes of the unique, but delicate, human vocal fold mucosa. The ability to develop new effective treatment methods is significantly limited by the physical inaccessibility and the extremely rare occasions under which healthy tissue biopsies can be obtained. Therefore, the interest in laryngological research has shifted to human oral (buccal) mucosa, a similar and more easily available tissue. The harvesting process is less invasive and accompanied with faster healing and less scarring, compared to vocal fold mucosa. Here we report a descriptive proteomic comparison of paired human buccal and vocal fold mucosa by high‐resolution mass spectrometry (CID‐MS/MS). Our study identified a total of 1575 proteins detected within both tissues that are highly consistent in several crucial biological processes, cellular components, and molecular functions. Hence, our proteomic analysis will provide a fundamental resource for the laryngological research community.

Growth Factors, Reactive Oxygen Species, and Metformin-Promoters of the Wound Healing Process in Burns?

Burns can be caused by various factors and have an increased risk of infection that can seriously delay the wound healing process. Chronic wounds caused by burns represent a major health problem. Wound healing is a complex process, orchestrated by cytokines, growth factors, prostaglandins, free radicals, clotting factors, and nitric oxide. Growth factors released during this process are involved in cell growth, proliferation, migration, and differentiation. Reactive oxygen species are released in acute and chronic burn injuries and play key roles in healing and regeneration. The main aim of this review is to present the roles of growth factors, reactive oxygen species, and metformin in the healing process of burn injuries.

Novel immortalized human vocal fold epithelial cell line: In vitro tool for mucosal biology

Study of vocal fold (VF) mucosal biology requires essential human vocal fold epithelial cell (hVFE) lines for use in appropriate model systems. We steadily transfected a retroviral construct containing human telomerase reverse transcriptase (hTERT) into primary normal hVFE to establish a continuously replicating hVFE cell line. Immortalized hVFE across passages have cobblestone morphology, express epithelial markers cytokeratin 4, 13 and 14, induced hTERT gene and protein expression, have similar RNAseq profiling, and can continuously grow for more than 8 months. DNA fingerprinting and karyotype analysis demonstrated that immortalized hVFE were consistent with the presence of a single cell line. Validation of the hVFE, in a three‐dimensional in vitro VF mucosal construct revealed a multilayered epithelial structure with VF epithelial cell markers. Wound scratch assay revealed higher migration capability of the immortalized hVFE on the surface of collagen‐fibronectin and collagen gel containing human vocal fold fibroblasts (hVFF). Collectively, our report demonstrates the first immortalized hVFE from true VFs providing a novel and invaluable tool for the study of epithelial cell‐fibroblast interactions that dictate disease and health of this specialized tissue.

Silencing SIX1 inhibits epithelial mesenchymal transition through regulating TGF-β/Smad2/3 signaling pathway in papillary thyroid carcinoma

OBJECTIVE

To investigate the sineoculis homeobox homolog 1 (SIX1) affect the epithelial mesenchymal transition (EMT) in papillary thyroid carcinoma (PTC) through regulating TGF-β/Smad2/3 signaling pathway.

METHODS

The SIX1 expression in cytological specimens, tissues or PTC cell lines was detected by qRT-PCR, western blotting or immunohistochemistry. A series of vitro experiments including flow cytometry, CCK-8, wound-healing and Transwell were used to evaluate the biological characteristics in a PTC cell line (NPA cells), which were divided into Blank, Negative control (NC), SIX1, SIX1-siRNA, LY-364947 (TGF-β/Smad2/3 pathway inhibitor) and SIX1 + LY-364947 groups. TGF-β/Smad2/3 pathway and EMT related protein expression were measured by qRT-PCR and western blotting.

RESULTS

SIX1 mRNA expression was increased in cytological specimens from PTC patients as compared with the non-toxic nodular goitre (NTG) patients. Moreover, compared with adjacent normal tissues, expressions of SIX1, N-cadherin and Vimentin were higher while E-cadherin was lower in PTC tissues; and SIX1 was positively correlated with N-cadherin and Vimentin but was negatively correlated with E-cadherin. Furthermore, the SIX1 expression was associated with histopathology, extrathyroidal extension (ETE), lymph node metastasis (LNM), pT stage, TNM stage, and distant metastasis. In addition, the expressions of TGFβ1, p-SMAD2/3, N-cadherin and Vimentin were downregulated in NPA cells after LY-364947 treatment with upregulated E-cadherin, decreased cell proliferation and metastasis, and enhanced cell apoptosis, which was reversed by SIX1 overexpression.

CONCLUSION

Silencing SIX1 can inhibit TGF-β/Smad2/3 pathway, thereby suppressing EMT in PTC, which may be a novel avenue for the treatment of PTC.

Tissue engineering applications in otolaryngology-The state of translation

While tissue engineering holds significant potential to address current limitations in reconstructive surgery of the head and neck, few constructs have made their way into routine clinical use. In this review, we aim to appraise the state of head and neck tissue engineering over the past five years, with a specific focus on otologic, nasal, craniofacial bone, and laryngotracheal applications. A comprehensive scoping search of the PubMed database was performed and over 2000 article hits were returned with 290 articles included in the final review. These publications have addressed the hallmark characteristics of tissue engineering (cellular source, scaffold, and growth signaling) for head and neck anatomical sites. While there have been promising reports of effective tissue engineered interventions in small groups of human patients, the majority of research remains constrained to in vitro and in vivo studies aimed at furthering the understanding of the biological processes involved in tissue engineering. Further, differences in functional and cosmetic properties of the ear, nose, airway, and craniofacial bone affect the emphasis of investigation at each site. While otolaryngologists currently play a role in tissue engineering translational research, continued multidisciplinary efforts will likely be required to push the state of translation towards tissue-engineered constructs available for routine clinical use.

LEVEL OF EVIDENCE

NA.

Prolactin may serve as a regulator to promote vocal fold wound healing

Reduced prolactin (PRL) has been shown to delay wound healing with a limited understanding of the underlying mechanisms. Here, we aim to explore the role of PRL in the repair of vocal fold (VF) injury. A microarray was used to detect the expressed levels of PRL in rat VF tissue at 1, 4, and 8 weeks after VF injury compared with normal uninjured rats. Then, a systematic bioinformatics analysis has been conducted to explore the literature-based biology network and signaling pathways involved in the repair of VF injury. The expression of PRL was significantly decreased in all VF injury groups (week 1, 4, and 8) compared with the control group (F stats = 280.34; P=4.88e-14), with no significant difference among the three VF injury groups (F stats = 1.97; P=0.18). Wounding has been shown to interfere with both PRL-promoting and inhibiting pathways that were involved in wound healing, including 11 PRL inhibitors and 6 PRL promoters. Our results reveal decreased PRL expression levels in VF injury, which is not in favor of the wound healing. The pathways identified may help in understanding the role of PRL as a treatment target for VF wound healing.

An in vitro scaffold-free epithelial-fibroblast coculture model for the larynx

OBJECTIVES/HYPOTHESIS

Physiologically relevant, well-characterized in vitro vocal fold coculture models are needed to test the effects of various challenges and therapeutics on vocal fold physiology. We characterize a healthy state coculture model, created by using bronchial/tracheal epithelial cells and immortalized vocal fold fibroblasts. We also demonstrate that this model can be induced into a fibroplastic state to overexpress stress fibers using TGFβ1.

STUDY DESIGN

In vitro.

METHODS

Cell metabolic activity of immortalized human vocal fold fibroblasts incubated in different medium combinations was confirmed with an MTT (3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazolium bromide) assay. Fibroblasts were grown to confluence, and primary bronchial/tracheal epithelial cells suspended in coculture medium were seeded directly over the base layer of the fibroblasts. Cells were treated with transforming growth factor β1 (TGFβ1) to induce myofibroblast formation. Cell shape and position were confirmed by live cell tracking, fibrosis was confirmed by probing for α smooth muscle actin (αSMA), and phenotype was confirmed by immunostaining for vimentin and E-cadherin.

RESULTS

Fibroblasts retain metabolic activity in coculture epithelial medium. Live cell imaging revealed a layer of epithelial cells atop fibroblasts. αSMA expression was enhanced in TGFβ1-treated cells, confirming that both cell types maintained a healthy phenotype in coculture, and can be induced into overexpressing stress fibers. Vimentin and E-cadherin immunostaining show that cells retain phenotype in coculture.

CONCLUSIONS

These data lay effective groundwork for a functional coculture model that retains the reproducibility necessary to serve as a viable diagnostic and therapeutic screening platform.

LEVEL OF EVIDENCE

NA Laryngoscope, 127:E185-E192, 2017.

Tissue engineering in the larynx and airway

PURPOSE OF REVIEW

Tissue engineering is a rapidly expanding field in medicine and involves regeneration and restoration of many organs, including larynx and the airways. Currently, this is not included in routine practice; however, a number of clinical trials in humans are ongoing or starting. This review will cover publications during the past 2 years and the focus is on larynx and trachea.

RECENT FINDINGS

Recent reports concern the development and investigations of cell therapies, including biological factors such as growth factors which promote healing of damage and increased vascular support of the tissue. A separate section concerns studies of stromal cells and stem cells in tissue engineering. Cell therapies and treatment with biological active factors are often combined with the development of scaffolds to support or reconstruct the soft tissue in the larynx or the cartilages in trachea or larynx. New techniques for scaffold construction, such as 3D printing, are developed. The trend in the recent publications is to combine these methods.

SUMMARY

Recent advances in tissue engineering of the larynx and trachea include the development of cell therapies or treatment with biological active factors often in combination with scaffolds.

Anemonin improves intestinal barrier restoration and influences TGF-β1 and EGFR signaling pathways in LPS-challenged piglets

The present study was aimed at investigating whether dietary anemonin could alleviate LPS-induced intestinal injury and improve intestinal barrier restoration in a piglet model. Eighteen 35-d-old pigs were randomly assigned to three treatment groups (control, LPS and LPS+anemonin). The control and LPS groups were fed a basal diet, and the LPS + anemonin group received the basal diet + 100 mg anemonin/kg diet. After 21 d of feeding, the LPS- and anemonin-treated piglets received i.p. administration of LPS; the control group received saline. At 4 h post-injection, jejunum samples were collected. The results showed that supplemental anemonin increased villus height and transepithelial electrical resistance, and decreased crypt depth and paracellular flux of dextran (4 kDa) compared with the LPS group. Moreover, anemonin increased tight junction claudin-1, occludin and ZO-1 expression in the jejunal mucosa, compared with LPS group. Anemonin also decreased TNF-α, IL-6, IL-8 and IL-1β mRNA expression. Supplementation with anemonin also increased TGF-β1 mRNA and protein expression, Smad4 and Smad7 mRNA expressions, and epidermal growth factor and epidermal growth factor receptor (EGFR) mRNA expression in the jejunal mucosa. These findings suggest that dietary anemonin attenuates LPS-induced intestinal injury by improving mucosa restoration, alleviating intestinal inflammation and influencing TGF-β1 canonical Smads and EGFR signaling pathways.