The use of lipid microtubes as a novel slow-release delivery system for laryngeal injection

Fabrication of Lipid Nanotubules by Ultrasonic Drag Force

This work reports a new method of fabricating lipid nanotubules using ultrasonic Stokes drag force in theory and experiment. Ultrasonic Stokes drag force generated using a planar piezoelectric ultrasonic transducer in a remotely controllable way is introduced. When ultrasonic Stokes drag force is applied on lipid vesicles, the lipid nanotubules attached can be dragged out from the lipid film. In order to demonstrate the formation mechanism of the lipid nanotubules produced by ultrasonic drag force clearly, a theoretical kinetic model is developed. In the experiments, the lipid nanotubules can be rapidly and efficiently fabricated using this ultrasonic transducer both in deionized water and NaCl solutions with different concentrations. The stretching speed of the lipid nanotubules can reach 33 μm/s, approximately 10 times faster than that of the existing methods. The formed lipid nanotubules have a diameter of 600 ± 100 nm (>80%). The length can reach the millimeter level. This work provided a remotely controllable, highly efficient, high-velocity, and solution environment-independent approach for fabricating lipid nanotubules.

Glycoside scutellarin enhanced CD-MOF anchoring for laryngeal delivery

It is essential to develop new carriers for laryngeal drug delivery in light of the lack of therapy in laryngeal related diseases. When the inhalable micron-sized crystals of γ-cyclodextrin metal-organic framework (CD-MOF) was utilized as dry powder inhalers (DPIs) carrier with high fine particle fraction (FPF), it was found in this research that the encapsulation of a glycoside compound, namely, scutellarin (SCU) in CD-MOF could significantly enhance its laryngeal deposition. Firstly, SCU loading into CD-MOF was optimized by incubation. Then, a series of characterizations were carried out to elucidate the mechanisms of drug loading. Finally, the laryngeal deposition rate of CD-MOF was 57.72 ± 2.19% improved by SCU, about two times higher than that of CD-MOF, when it was determined by Next Generation Impactor (NGI) at 65 L/min. As a proof of concept, pharyngolaryngitis therapeutic agent dexamethasone (DEX) had improved laryngeal deposition after being co-encapsulated with SCU in CD-MOF. The molecular simulation demonstrated the configuration of SCU in CD-MOF and its contribution to the free energy of the SCU@CD-MOF, which defined the enhanced laryngeal anchoring. In conclusion, the glycosides-like SCU could effectively enhance the anchoring of CD-MOF particles to the larynx to facilitate the treatment of laryngeal diseases.

A hyaluronan/methylcellulose-based hydrogel for local cell and biomolecule delivery to the central nervous system

Regenerative medicine strategies rely on exogenous cell transplantation and/or endogenous cell stimulation. Biomaterials can help to increase the regenerative potential of cells and biomolecules by controlling transplanted cell fate and provide a local, sustained release of biomolecules. In this review, we describe the use of a hyaluronan/methylcellulose (HAMC)-based hydrogel as a delivery vehicle to the brain, spinal cord, and retina to promote cellular survival and tissue repair. We discuss various controlled release strategies to prolong the delivery of factors for neuroprotection. The versatility of this hydrogel for a diversity of applications highlights its potential to enhance cell- and biomolecule-based treatment strategies.

Functional remodeling after vocal fold injury by small intestinal submucosa gel containing hepatocyte growth factor

A biomaterial derived from porcine small intestinal submucosa (SIS) was used in smart drug delivery and tissue remodeling. SIS suspensions were easily formulated by simple mixing with the drug of choice and formed an in situ gel upon injection into tissues, enabling them to act as protein drug depots. This study was conducted to determine whether functional remodeling of an injured vocal fold (VF) could be achieved by hepatocyte growth factor (HGF)-containing SIS in situ-forming gel after VF injury in a rabbit model. To accomplish this, we loaded HGF in SIS suspensions and observed a gradual, sustained release of HGF for at least 21 days in vitro. Evaluation of the in vivo efficacy demonstrated that the HGF and HGF-loaded SIS treated VFs showed improved mucosal healing when compared with the PBS-injected VFs. Histopathological evaluations revealed that treatment with the HGF/SIS group alone successfully ameliorated the deposition of type I collagen and increased synthesis of hyaluronic acids relative to the PBS group at three months post-injury. Functional analyses showed that the HGF/SIS group prevented deterioration of mucosal vibration and induced significant improvement in the mean viscoelastic modulus, but that other groups failed to achieve functional rescue of VF biomechanics. Additionally, the VF oscillation in the HGF/SIS group was superior to that in the HGF group. The results of this study suggest that SIS in situ gel has the potential for use as an HGF delivery carrier for enhancement of wound healing and improvement of functional remodeling following VF injury.

Radiation fibrosis of the vocal fold: from man to mouse

OBJECTIVES/HYPOTHESIS

To characterize fundamental late tissue effects in the human vocal fold following radiation therapy. To develop a murine model of radiation fibrosis in order to ultimately develop both treatment and prevention paradigms.

DESIGN

Translational study using archived human and fresh murine irradiated vocal fold tissue.

METHODS

1) Irradiated vocal fold tissue from patients undergoing laryngectomy for loss of function from radiation fibrosis was identified from pathology archives. Histomorphometry, immunohistochemistry, and whole-genome microarray, as well as real-time transcriptional analyses, were performed. 2) Focused radiation to the head and neck was delivered to mice in a survival fashion. One month following radiation, vocal fold tissue was analyzed with histomorphometry, immunohistochemistry, and real-time PCR transcriptional analysis for selected markers of fibrosis.

RESULTS

Human irradiated vocal folds demonstrated increased collagen transcription, with increased deposition and disorganization of collagen in both the thyroarytenoid muscle and the superficial lamina propria. Fibronectin were increased in the superficial lamina propria. Laminin decreased in the thyroarytenoid muscle. Whole genome microarray analysis demonstrated increased transcription of markers for fibrosis, oxidative stress, inflammation, glycosaminoglycan production, and apoptosis. Irradiated murine vocal folds demonstrated increases in collagen and fibronectin transcription and deposition in the lamina propria. Transforming growth factor (TGF)-β increased in the lamina propria.

CONCLUSION

Human irradiated vocal folds demonstrate molecular changes leading to fibrosis that underlie loss of vocal fold pliability occurring in patients following laryngeal irradiation. The irradiated murine tissue demonstrates similar findings, and this mouse model may have utility in creating prevention and treatment strategies for vocal fold radiation fibrosis.