Effects of Hepatocyte Growth Factor Injection and Reinjection on Healing in the Rabbit Vocal Fold

Characterization of intrauterine growth, proliferation and biomechanical properties of the murine larynx

Current research approaches employ traditional tissue engineering strategies to promote vocal fold (VF) tissue regeneration, whereas recent novel advances seek to use principles of developmental biology to guide tissue generation by mimicking native developmental cues, causing tissue or allogenic/autologous progenitor cells to undergo the regeneration process. To address the paucity of data to direct VF differentiation and subsequent new tissue formation, we characterize structure-proliferation relationships and tissue elastic moduli over embryonic development using a murine model. Growth, cell proliferation, and tissue biomechanics were taken at E13.5, E15.5, E16.5, E18.5, P0, and adult time points. Quadratic growth patterns were found in larynx length, maximum transverse diameter, outer dorsoventral diameter, and VF thickness; internal VF length was found to mature linearly. Cell proliferation measured with EdU in the coronal and transverse planes of the VFs was found to decrease with increasing age. Exploiting atomic force microscopy, we measured significant differences in tissue stiffness across all time points except between E13.5 and E15.5. Taken together, our results indicate that as the VF mature and develop quadratically, there is a concomitant tissue stiffness increase. Greater gains in biomechanical stiffness at later prenatal stages, correlated with reduced cell proliferation, suggest that extracellular matrix deposition may be responsible for VF thickening and increased biomechanical function, and that the onset of biomechanical loading (breathing) may also contribute to increased stiffness. These data provide a profile of VF biomechanical and growth properties that can guide the development of biomechanically-relevant scaffolds and progenitor cell differentiation for VF tissue regeneration.

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.

Human hepatocytes loaded in 3D bioprinting generate mini-liver

BACKGROUND

Because of an increasing discrepancy between the number of potential liver graft recipients and the number of organs available, scientists are trying to create artificial liver to mimic normal liver function and therefore, to support the patient's liver when in dysfunction. 3D printing technique meets this purpose. The present study was to test the feasibility of 3D hydrogel scaffolds for liver engineering.

METHODS

We fabricated 3D hydrogel scaffolds with a bioprinter. The biocompatibility of 3D hydrogel scaffolds was tested. Sixty nude mice were randomly divided into four groups, with 15 mice in each group: control, hydrogel, hydrogel with L02 (cell line HL-7702), and hydrogel with hepatocyte growth factor (HGF). Cells were cultured and deposited in scaffolds which were subsequently engrafted into livers after partial hepatectomy and radiation-induced liver damage (RILD). The engrafted tissues were examined after two weeks. The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin, total bilirubin, CYP1A2, CYP2C9, glutathione S-transferase (a-GST), and UDP-glucuronosyl transferase (UGT-2) were compared among the groups. Hematoxylin-eosin (HE) staining and immunohistochemistry of cKit and cytokeratin 18 (CK18) of engrafted tissues were evaluated. The survival time of the mice was also compared among the four groups.

RESULTS

3D hydrogel scaffolds did not impact the viability of cells. The levels of ALT, AST, albumin, total bilirubin, CYP1A2, CYP2C9, a-GST and UGT-2 were significantly improved in mice engrafted with 3D scaffold loaded with L02 compared with those in control and scaffold only (P<0.05). HE staining showed clear liver tissue and immunohistochemistry of cKit and CK18 were positive in the engrafted tissue. Mice treated with 3D scaffold+L02 cells had longer survival time compared with those in control and scaffold only (P<0.05).

CONCLUSION

3D scaffold has the potential of recreating liver tissue and partial liver functions and can be used in the reconstruction of liver tissues.