Browsing by Subject "Tissue engineering"

Now showing 1 - 10 of 22
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    Biomedical Engineering Advancements after Management of Myelomeningocele Study (MOMS): A Narrative Review
    (University of Pittsburgh Library System, 2022) Campbell, Natalie C.; Trippel, Stephen B.; Nauman, Eric A.; Orthopaedic Surgery, School of Medicine
    Spina bifida is a neural tube defect resulting from an incomplete closure of the caudal neuropore. The most debilitating form of spina bifida, myelomeningocele (MMC), can present with Chiari II malformation with concomitant hydrocephalus, bowel and bladder abnormalities, and impaired motor function of the lower limbs. The incidence rate of spina bifida is 3.4 per 10,000 live births reported within the US. Advancements in the standard therapy, namely prenatal intervention pioneered by the Management of Myelomeningocele Study (MOMS), have aimed to reduce maternal and fetal complications, and yet complications were increased, calling for the need of further improvements. Beyond current standard interventions for MMC, the most promising developments have employed various biomedical methods ranging from isolated stem cell injections to biodegradable scaffold patches. These scaffolds can be biologic or synthetic and are often incorporated with bioactive proteins or stem cells. This review discusses the benefits and limitations of post-MOMS era biomedical engineering intervention articles found in 3 medical and biomedical databases consisting of systematic reviews, meta-analyses, randomized control trials, and experimental studies. After analysis of the advancements and limitations of these studies, an engineered synthetic biodegradable scaffold seeded with bioactive proteins and stem cells create a superior scaffold possessing watertight impermeability and cytocompatibility for successful coverage and host integration with minimal inflammation. Coupled with minimally invasive intra-amniotic injection delivery, an earlier mitigation could further prevent progression of poor neurologic outcomes, and possibly even regenerate neuronal tissue in patients with MMC.
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    Effects of interstitial fluid flow and cell compression in FAK and SRC activities in chondrocytes
    (2013-11-08) Cho, Eunhye; Na, Sungsoo; Yokota, Hiroki, 1955-; Li, Jiliang
    Articular cartilage is subjected to dynamic mechanical loading during normal daily activities. This complex mechanical loading, including cell deformation and interstitial fluid flow, affects chondrocyte mechano-chemical signaling and subsequent cartilage homeostasis and remodeling. Focal adhesion kinase (FAK) and Src are known to be main mechanotransduction proteins, but little is known about the effect of mechanical loading on FAK and Src under its varying magnitudes and types. In this study, we addressed two questions using C28/I2 chondrocytes subjected to the different types and magnitudes of mechanical loading: Does a magnitude of the mechanical loading affect activities of FAK and Src? Does a type of the mechanical loading also affect their activities? Using fluorescence resonance energy transfer (FRET)-based FAK and Src biosensor in live C28/I2 chondrocytes, we monitored the effects of interstitial fluid flow and combined effects of cell deformation/interstitial fluid flow on FAK and Src activities. The results revealed that both FAK and Src activities in C28/I2 chondrocytes were dependent on the different magnitudes of the applied fluid flow. On the other hand, the type of mechanical loading differently affected FAK and Src activities. Although FAK and Src displayed similar activities in response to interstitial fluid flow only, simultaneous application of cell deformation and interstitial fluid flow induced differential FAK and Src activities possibly due to the additive effects of cell deformation and interstitial fluid flow on Src, but not on FAK. Collectively, the data suggest that the intensities and types of mechanical loading are critical in regulating FAK and Src activities in chondrocytes.
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    Enhanced Viability of Endothelial Colony Forming Cells in Fibrin Microbeads for Sensor Vascularization
    (MDPI AG, 2015-09-18) Gandhi, Jarel K.; Zivkovic, Lada; Fisher, John P.; Yoder, Mervin C.; Brey, Eric M.; Department of Pediatrics, School of Medicine
    Enhanced vascularization at sensor interfaces can improve long-term function. Fibrin, a natural polymer, has shown promise as a biomaterial for sensor coating due to its ability to sustain endothelial cell growth and promote local vascularization. However, the culture of cells, particularly endothelial cells (EC), within 3D scaffolds for more than a few days is challenging due to rapid loss of EC viability. In this manuscript, a robust method for developing fibrin microbead scaffolds for long-term culture of encapsulated ECs is described. Fibrin microbeads are formed using sodium alginate as a structural template. The size, swelling and structural properties of the microbeads were varied with needle gauge and composition and concentration of the pre-gel solution. Endothelial colony-forming cells (ECFCs) were suspended in the fibrin beads and cultured within a perfusion bioreactor system. The perfusion bioreactor enhanced ECFCs viability and genome stability in fibrin beads relative to static culture. Perfusion bioreactors enable 3D culture of ECs within fibrin beads for potential application as a sensor coating.
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    Exploring Chondrocyte Integrin Regulation of Growth Factor IGF-I Expression from a Transient pAAV Vector
    (2013-08-20) Ratley, Samantha Kay; Trippel, Stephen B.; Lin, Chien-Chi; Stocum, David L.
    Insulin-like Growth Factor I (IGF-I) is a growth factor that stimulates both mitogenic and anabolic responses in articular chondrocytes. While it has been shown that exogenous IGF-I can regulate chondrocyte integrins, little is known regarding regulatory effects of IGF-I produced from a transiently expressed plasmid based adeno-associated virus (pAAV) vector. Because chondrocytes are using cellular machinery to overexpress IGF-I, it is of interest to see whether or not pAAV IGF-I will significantly upregulate or downregulate chondrocyte integrins. Additionally, it is of interest to know whether chondrocyte adhesion through integrins will have any regulatory effects on the production of IGF-I from the transgene. Therefore, this study will ascertain if pAAV IGF-I will have similar effects that exogenous IGF-I has on integrin regulation and if integrin silencing mechanisms will affect the production of IGF-I from the transgene. To test these hypotheses, adult articular chondrocytes were doubly transfected with the pAAV vector for IGF-I and short interference ribonucleic acid (siRNA) for integrins beta 1 and alpha V. Gene products were monitored at the transcriptional levels using quantitative real time polymerase chain reactions (qPCR) and IGF-I protein production was monitored at the translational level using enzyme linked immunoabsorbant assays (ELISAs). Adult articular chondrocytes doubly transfected were encapsulated in a three dimensional hydrogel system to simulate an in vivo environment. Samples were collected for analysis at days 2, 4, and 6 post encapsulation. Results show that IGF-I treatment with the pAAV vector does not cause significant changes in the transcriptional regulation of the beta 1 integrin in a three dimensional hydrogel system. The pAAV IGF-I vector did not cause significant regulatory changes on integrin alpha V at any time point during the experiment. Additionally, by knocking down the expression levels of integrins by using siRNA, it was shown that integrin knockdown does not have a significant regulatory effect on transcriptional or translational expression levels of IGF-I from the pAAV vector.
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    In Vitro Multitissue Interface Model Supports Rapid Vasculogenesis and Mechanistic Study of Vascularization across Tissue Compartments
    (ACS Publications, 2016-08-31) Bruno, Kevin P.; Chen, Xuemei; Weibel, Justin A.; Thiede, Stephanie N.; Garimella, Suresh V.; Yoder, Mervin C.; Voytik-Harbin, Sherry L.; Department of Pediatrics, IU School of Medicine
    A significant challenge facing tissue engineers is the design and development of complex multitissue systems, including vascularized tissue-tissue interfaces. While conventional in vitro models focus on either vasculogenesis (de novo formation of blood vessels) or angiogenesis (vessels sprouting from existing vessels or endothelial monolayers), successful therapeutic vascularization strategies will likely rely on coordinated integration of both processes. To address this challenge, we developed a novel in vitro multitissue interface model in which human endothelial colony forming cell (ECFC)-encapsulated tissue spheres are embedded within a surrounding tissue microenvironment. This highly reproducible approach exploits biphilic surfaces (nanostructured surfaces with distinct superhydrophobic and hydrophilic regions) to (i) support tissue compartments with user-specified matrix composition and physical properties as well as cell type and density and (ii) introduce boundary conditions that prevent the cell-mediated tissue contraction routinely observed with conventional three-dimensional monodispersion cultures. This multitissue interface model was applied to test the hypothesis that independent control of cell-extracellular matrix (ECM) and cell-cell interactions would affect vascularization within the tissue sphere as well as across the tissue-tissue interface. We found that high-cell-density tissue spheres containing 5 × 10(6) ECFCs/mL exhibit rapid and robust vasculogenesis, forming highly interconnected, stable (as indicated by type IV collagen deposition) vessel networks within only 3 days. Addition of adipose-derived stromal cells (ASCs) in the surrounding tissue further enhanced vasculogenesis within the sphere as well as angiogenic vessel elongation across the tissue-tissue boundary, with both effects being dependent on the ASC density. Overall, results show that the ECFC density and ECFC-ASC crosstalk, in terms of paracrine and mechanophysical signaling, are critical determinants of vascularization within a given tissue compartment and across tissue interfaces. This new in vitro multitissue interface model and the associated mechanistic insights it yields provide guiding principles for the design and optimization of multitissue vascularization strategies for research and clinical applications.
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    Investigating pediatric disorders with induced pluripotent stem cells
    (Springer Nature, 2018-10) Durbin, Matthew D.; Cadar, Adrian G.; Chun, Young W.; Hong, Charles C.; Pediatrics, School of Medicine
    The study of disease pathophysiology has long relied on model systems, including animal models and cultured cells. In 2006, Shinya Yamanaka achieved a breakthrough by reprogramming somatic cells into induced pluripotent stem cells (iPSCs). This revolutionary discovery provided new opportunities for disease modeling and therapeutic intervention. With established protocols, investigators can generate iPSC lines from patient blood, urine, and tissue samples. These iPSCs retain ability to differentiate into every human cell type. Advances in differentiation and organogenesis move cellular in vitro modeling to a multicellular model capable of recapitulating physiology and disease. Here, we discuss limitations of traditional animal and tissue culture models, as well as the application of iPSC models. We highlight various techniques, including reprogramming strategies, directed differentiation, tissue engineering, organoid developments, and genome editing. We extensively summarize current established iPSC disease models that utilize these techniques. Confluence of these technologies will advance our understanding of pediatric diseases and help usher in new personalized therapies for patients.
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    Laryngeal Reconstruction Using Tissue-Engineered Implants in Pigs: A Pilot Study
    (Wiley, 2021-10) Brookes, Sarah; Zhang, Lujuan; Puls, Theodore J.; Kincaid, John; Voytik-Harbin, Sherry; Halum, Stacey; Otolaryngology -- Head and Neck Surgery, School of Medicine
    Objective/hypothesis: There are currently no treatments available that restore dynamic laryngeal function after hemilaryngectomy. We have shown that dynamic function can be restored post hemilaryngectomy in a rat model. Here, we report in a first of its kind, proof of concept study that this previously published technique is scalable to a porcine model. Study design: Animal study. Methods: Muscle and fat biopsies were taken from three Yucatan minipigs. Muscle progenitor cells (MPCs) and adipose stem cells (ASCs) were isolated and cultured for 3 weeks. The minipigs underwent a left laterovertical partial laryngectomy sparing the left arytenoid cartilage and transecting the recurrent laryngeal nerve. Each layer was replaced with a tissue-engineered implant: 1) an acellular mucosal layer composed of densified Type I oligomeric collagen, 2) a skeletal muscle layer composed of autologous MPCs and aligned oligomeric collagen differentiated and induced to express motor endplates (MEE), and 3) a cartilage layer composed of autologous ASCs and densified oligomeric collagen differentiated to cartilage. Healing was monitored at 2 and 4 weeks post-op, and at the 8 week study endpoint. Results: Animals demonstrated appropriate weight gain, no aspiration events, and audible phonation. Video laryngoscopy showed progressive healing with vascularization and re-epithelialization present at 4 weeks. On histology, there was no immune reaction to the implants and there was complete integration into host tissue with nerve and vascular ingrowth. Conclusions: This pilot study represents a first in which a transmural vertical partial laryngectomy was performed and successfully repaired with a customized, autologous stem cell-derived multi-layered tissue-engineered implant.
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    Microstructured Electroceutical Fiber-Device for Inhibition of Bacterial Proliferation in Wounds
    (Wiley, 2023) van der Elst, Louis Alexandre; Gokce, Merve; Coulter, Jeffery Robert; Cavdar, Zeynep Burcu; Koraganji, Veda Narayana; Ozturk, Murat; Ghatak, Subhadip; Sen, Chandan K.; Gumennik, Alexander; Surgery, School of Medicine
    Antibiotic-resistant infections caused by bacterial pathogens pose a serious threat to public health, hampering wound healing and causing significant morbidities worldwide. A biomedical fiber-device that functions as a drugless antiseptic is introduced as a solution to this problem. Through stitching, piercing, or topical application to the wound, this fiber slows down the proliferation of pathogenic bacteria, thereby reducing the risks associated with inflammation and inhibiting infections. The fiber's bacterial proliferation inhibition function is based on the galvanic effect, which disturbs bacterial quorum sensing. Detailed herein are the fiber design optimization, scalable fabrication approach, electrical function characterization, and antiseptic function verification in cultures of typical wound pathogens. Such a fiber—mechanically and environmentally resilient, insensitive to harsh storage conditions with nominally infinite shelf-life, resulting from machining rather than pharmacochemical fabrication— provides a cost-effective and widely available alternative to current antibiotic treatments of physical injury.
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    Mouse and human islets survive and function after coating by biosilicification
    (American Physiological Society, 2013-11-15) Jaroch, David B.; Lu, Jing; Madangopal, Rajtarun; Stull, Natalie D.; Stensberg, Matthew; Shi, Jin; Kahn, Jennifer L.; Herrera-Perez, Ruth; Zeitchek, Michael; Sturgis, Jennifer; Robinson, J. Paul; Yoder, Mervin C.; Porterfield, D. Marshall; Mirmira, Raghavendra; Rickus, Jenna L.; Medicine, School of Medicine
    Inorganic materials have properties that can be advantageous in bioencapsulation for cell transplantation. Our aim was to engineer a hybrid inorganic/soft tissue construct by inducing pancreatic islets to grow an inorganic shell. We created pancreatic islets surrounded by porous silica, which has potential application in the immunoprotection of islets in transplantation therapies for type 1 diabetes. The new method takes advantage of the islet capsule surface as a template for silica formation. Mouse and human islets were exposed to medium containing saturating silicic acid levels for 9-15 min. The resulting tissue constructs were then cultured for up to 4 wk under normal conditions. Scanning electron microscopy and energy dispersive X-ray spectroscopy was used to monitor the morphology and elemental composition of the material at the islet surface. A cytokine assay was used to assess biocompatibility with macrophages. Islet survival and function were assessed by confocal microscopy, glucose-stimulated insulin release assays, oxygen flux at the islet surface, expression of key genes by RT-PCR, and syngeneic transplant into diabetic mice.
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    Multi-Layered Implant Approach for Hemilaryngectomy Reconstruction in a Porcine Model
    (Wiley, 2025) Wesson, Troy; Morrison, Rachel A.; Zhang, Lujuan; Brookes, Sarah; Kaefer, Sam; Finnegan, Patrick R.; Calcagno, Haley; Campiti, Vincent J.; Voytik-Harbin, Sherry; Halum, Stacey; Otolaryngology -- Head and Neck Surgery, School of Medicine
    Objective: Partial laryngectomies result in voice, swallowing, and airway impairment for thousands of patients in the United States each year. Treatment options for dynamic restoration of laryngeal function are limited. Thus, there is a need for new reconstructive approaches. Here, we evaluated early (4 week) outcomes of multi-layered mucosal-myochondral (MMC) implants when used to restore laryngeal form and function after hemilaryngectomy in a porcine model. Methods: Six Yucatan minipigs underwent transmural hemilaryngectomies followed by reconstruction with customized MMC implants aiming to provide site-appropriate localization of regenerated laryngeal tissues, while supporting laryngeal function. All implants were fabricated from polymeric collagen, with a subset of muscle and cartilage implants containing motor endplate-expressing muscle progenitor cells or cartilage-like cells differentiated from adipose stem cells, respectively. Vocalization and laryngeal electromyography (L-EMG) measurements with nerve conduction studies were performed post-operatively and compared with baseline along with gross and histological analyses of the healing response. Results: All animals (n = 6) survived and maintained airway patency, safe swallowing, and phonation, without the use of tracheostomy and/or gastrostomy tubes. Histological evaluation indicated no adverse tissue reaction or implant degradation, showing progressive regenerative remodeling with mucosa reformation and ingrowth of new muscle and cartilage. Preliminary L-EMG suggested weak but detectable motor unit action potentials. Although vocalization duration, frequency, and intensity decreased post-operatively, all animals retained vocal capacity and parameter recovery was evident over the study duration. Conclusion: Engineered collagen polymeric implants in the presence or absence of autologous cell populations may serve as a feasible reconstructive option to restore dynamic function after hemilaryngectomy. Long-term follow-up is needed to further assess functional outcomes.