Regenerating airway epithelium using fibrous biomimetic basement membranes.

There are reciprocal interactions between epithelial cells and underlying basement membrane. The resemblance of biomaterials to native basement membrane is thus critical for their success when used to regenerate epithelium-containing organs. Particularly, the use of nanofibers and the incorporation of basement membrane proteins may mimic both biophysical and biochemical properties of basement membrane, respectively. Herein we tested how electrospun polycaprolactone/heparin fibers with and without adsorbed laminin and collagen IV proteins affect epithelial cell functions. We found that airway epithelial cells attached, migrated, and proliferated on all scaffolds but protein-functionalized fibers promoted higher attachment, quicker migration, and increased proliferation. Fibers were then integrated on polyethylene scaffolds and cultured at an air-liquid interface. The detection of secretory and ciliated cell markers was higher in cells on polyethylene with fibers. These findings demonstrate that electrospun fibers incite beneficial epithelial cell responses and can be used in the fabrication of bioengineered functional epithelia.

Human amniotic epithelial cell transplantation improves scar remodeling in a rabbit model of acute vocal fold injury: a pilot study.

OBJECTIVE: To gain insight into the molecular mechanisms underlying the early stages of vocal fold extracellular matrix (ECM) remodeling after a mid-membranous injury resulting from the use of human amniotic epithelial cells (hAEC), as a novel regenerative medicine cell-based therapy. METHODS: Vocal folds of six female, New Zealand White rabbits were bilaterally injured. Three rabbits had immediate bilateral direct injection of 1 × 106 hAEC in 100 µl of saline solution (hAEC) and three with 100 µl of saline solution (controls, CTR). Rabbits were euthanized 6 weeks after injury. Proteomic analyses (in-gel trypsin protein digestion, LC-MS/MS, protein identification using Proteome Discoverer and the Uniprot Oryctolagus cuniculus (Rabbit) proteome) and histological analyses were performed. RESULTS: hAEC treatment significantly increased the expression of ECM proteins, elastin microfibril interface-located protein 1 (EMILIN-1) and myocilin that are primarily involved in elastogenesis of blood vessels and granulation tissue. A reactome pathway analysis showed increased activity of the anchoring fibril formation by collagen I and laminin, providing mechanical stability and activation of cell signaling pathways regulating cell function. hAEC increased the abundance of keratin 1 indicating accelerated induction of the differentiation programming of the basal epithelial cells and, thereby, improved barrier function. Lastly, upregulation of Rab GDP dissociation inhibitor indicates that hAEC activate the vesicle endocytic and exocytic pathways, supporting the exosome-mediated activation of cell-matrix and cell-to-cell interactions. CONCLUSIONS: This pilot study suggests that injection of hAEC into an injured rabbit vocal fold favorably alters ECM composition creating a microenvironment that accelerates differentiation of regenerated epithelium and promotes stabilization of new blood vessels indicative of accelerated and improved repair.

Improving the Osteogenicity of PCL Fiber Substrates by Surface-Immobilization of Bone Morphogenic Protein-2.

Polycaprolactone (PCL) fiber scaffolds are attractive, albeit inert, substrates for ligament regeneration, that may be improved by incorporating trophic factors to guide tissue remodeling in vivo. In particular, immobilization of bone morphogenic protein-2 (BMP-2) to the scaffold surface may facilitate rapid and robust integration of the scaffold with adjacent bone tissues. As a first step toward testing this, model PCL surfaces were modified by the addition of heparin (Hep) and BMP-2 to facilitate osteoblastic differentiation. Specifically, Hep was combined with PCL at 0, 0.5, and 1 wt% (denoted as PCL, PCL-0.5Hep, and PCL-1Hep), cast into films, and then BMP-2 was immobilized to surfaces by either adsorption and covalent conjugation. Here, BMP-2 concentration increased systematically with incorporation of Hep, and higher concentrations were achieved by covalent conjugation. Next, blends were electrospun to form thin meshes with fiber diameters of 0.92, 0.62, and 0.54 µm for PCL, PCL-0.5Hep, and PCL-1Hep, respectively. Mesenchymal stem cells (MSCs) had no difficulty attaching to and proliferating on all meshes. Lastly, PCL-1Hep meshes were prepared with adsorbed or covalently conjugated BMP-2 and cultured with MSCs in the absence of osteogenic factors. Under these conditions, alkaline phosphatase activity and deposition of bone sialoprotein, osteopontin, and calcium minerals-markers of osteoblastic differentiation-were significantly higher on surfaces with immobilized BMP-2. Together, these data indicate that covalent immobilization of trophic factors confers bioactivity to scaffolds, which may be applied in a spatially controlled manner for ligament regeneration and bone integration.

Synergistic Nanomedicine: Passive, Active, and Ultrasound-Triggered Drug Delivery in Cancer Treatment.

Nanocarriers are heavily researched as drug delivery vehicles capable of sequestering antineoplastic agents and then releasing their contents at the desired location. The feasibility of using such carriers stems from their ability to produce a multimodel delivery system whereby passive, ligand and triggered targeting can be applied in the fight against cancer. Passive targeting capitalizes on the leaky nature of tumor tissue which allows for the extravasation of particles with a size smaller than 0.5 µm into the tumors. Ligand targeting utilizes the concept of receptor-mediated endocytosis and involves the conjugation of ligands onto the surface of nanoparticles, while triggered targeting involves the use of external and internal stimuli to release the carriers contents upon reaching the diseased location. In this review, micelles and liposomes have been considered due to the promising results they have shown in vivo and in vitro and their potential for advancements into clinical trials. Thus, this review focuses on the most recent advancements in the field of micellar and liposomal drug delivery and considers the synergistic effect of passive- and ligand-targeting strategies, and the use of ultrasound in triggering drug release at the tumor site.