Browsing by Author "Trubelja, Alen"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Directing Collective Epithelial Morphology Using a Light-Based Carving Tool
    (2022-08-11) Trubelja, Alen; Grande-Allen, Kathryn J; Harrington, Daniel A
    Head and Neck Cancer (HNC) refers to tumors that originate predominantly in the mouth, nose, and throat, accounting for more than 10,000 deaths yearly in the US. Radiotherapy is a common treatment for HNC. Patients that undergo radiotherapy (RT) oftentimes develop Xerostomia (dry mouth). This is an iatrogenic disorder with no cure, which significantly impacts quality of life. Xerostomia results from irreversible damage to the salivary glands (SG), which are complex branched organs with an unmet need for regenerative therapy. RT causes apoptosis of secretory salivary acinar cells and their progenitor source in the ducts. Tissue engineering could offer a therapeutic solution by harvesting healthy SG tissue prior to RT, expanding these cells in vitro to form 3D spheroids, then creating functional tissue for implantation post-RT. During development, salivary glands form by repeated cleft and bud formation, forming a divergent, duct-to-acini architecture difficult to recapitulate with standard gel scaffolds. Recent advances in biofabrication have enabled high-resolution control over user-defined architectures within 3D tissue constructs. In this work, we leverage a subtractive manufacturing technique known as laser-based hydrogel degradation (LBHD) to guide collective epithelial morphology and exert spatiotemporal control over cell differentiation. We demonstrate the ability to carve features at high resolution within 3D tissue constructs. This thesis demonstrates the potential to direct clusters of salivary cells to migrate through the tunnels carved into hydrogels, form open lumens, and obey branching cues to form a rudimentary gland. This work has the potential to contribute to our understanding of how to create microscale glandular tissues.
  • Thumbnail Image
    Item
    Tissue Engineered, Hydrogel-Based Endothelial Progenitor Cell Therapy Robustly Revascularizes Ischemic Myocardium and Preserves Ventricular Function
    (Elsevier, 2014) Atluri, Pavan; Miller, Jordan S.; Emery, Robert J.; Hung, George; Trubelja, Alen; Cohen, Jeffrey E.; Lloyd, Kelsey; Han, Jason; Gaffey, Ann C.; MacArthur, John W.; Chen, Christopher S.; Woo, Y. Joseph
    Objectives: Cell-based angiogenic therapy for ischemic heart failure has had limited clinical impact, likely related to low cell retention (<1%) and dispersion. We developed a novel, tissue-engineered, hydrogel-based cell-delivery strategy to overcome these limitations and provide prolonged regional retention of myocardial endothelial progenitor cells at high cell dosage. Methods: Endothelial progenitor cells were isolated from Wistar rats and encapsulated in fibrin gels. In vitro viability was quantified using a fluorescent live-dead stain of transgenic enhanced green fluorescent protein+ endothelial progenitor cells. Endothelial progenitor cell-laden constructs were implanted onto ischemic rat myocardium in a model of acute myocardial infarction (left anterior descending ligation) for 4 weeks. Intramyocardial cell injection (2 × 106 endothelial progenitor cells), empty fibrin, and isolated left anterior descending ligation groups served as controls. Hemodynamics were quantified using echocardiography, Doppler flow analysis, and intraventricular pressure-volume analysis. Vasculogenesis and ventricular geometry were quantified. Endothelial progenitor cell migration was analyzed by using endothelial progenitor cells from transgenic enhanced green fluorescent protein+ rodents. Results: Endothelial progenitor cells demonstrated an overall 88.7% viability for all matrix and cell conditions investigated after 48 hours. Histologic assessment of 1-week implants demonstrated significant migration of transgenic enhanced green fluorescent protein+ endothelial progenitor cells from the fibrin matrix to the infarcted myocardium compared with intramyocardial cell injection (28 ± 12.3 cells/high power field vs 2.4 ± 2.1 cells/high power field, P = .0001). We also observed a marked increase in vasculogenesis at the implant site. Significant improvements in ventricular hemodynamics and geometry were present after endothelial progenitor cell-hydrogel therapy compared with control. Conclusions: We present a tissue-engineered, hydrogel-based endothelial progenitor cell-mediated therapy to enhance cell delivery, cell retention, vasculogenesis, and preservation of myocardial structure and function.