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3433 Tissue Engineered Nigrostriatal Pathway as a Test-Bed for Evaluating Axonal Pathophysiology in Parkinson’s disease
- Elisia Clark, Laura Struzyna, Wisberty Gordián-Vélez, Kacy Cullen
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- Journal:
- Journal of Clinical and Translational Science / Volume 3 / Issue s1 / March 2019
- Published online by Cambridge University Press:
- 26 March 2019, p. 25
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OBJECTIVES/SPECIFIC AIMS: Selective loss of long-projecting neural circuitry is a common feature of many neurodegenerative diseases, such as the vulnerable nigrostriatal pathway in Parkinson’s disease (PD). Current in vitro approaches for studying disease development generally do not mimic complex anatomical features of the afflicted substrates such as long axonal pathways between stereotypical neural populations. Such exquisite features are not only crucial for neural systems function but may also contribute to the preferential vulnerability and pathophysiological progression of these structures in neurodegenerative disease. We have previously developed micro-tissue engineered neural networks to recapitulate the anatomy of long-projecting cortical axonal tracts encased in a tubular hydrogel.1 Recently, we have extended this work to include the first tissue-engineered nigrostriatal pathway that was anatomically-inspired to replicate the structure and function of the native pathway.2 Notably, this tissue-engineered brain pathway possesses three-dimensional (3D) structure, multicellular composition, and architecture of long axonal tracts between distinct neuronal populations. Therefore, in the current study we apply this system as a biofidelic test-bed for evaluating axonal pathway development, maturation, and pathophysiology. METHODS/STUDY POPULATION: Dopaminergic neurons from the ventral mesencephalon and medium spiny neurons (MSNs) from the striatum were separately isolated from rat embryos. Tissue-engineered nigrostriatal pathways were formed by initially seeding dopaminergic neuron aggregates at one end of hollow hydrogel micro-columns with a central extracellular matrix, collectively spanning up to several centimeters in length. Several days later, tissue-engineered MSN aggregate was seeded on the other end and was allowed to integrate. Immunocytochemistry (ICC) and confocal microscopy were used to assess health, cytoarchitecture, synaptic integration, and mitochondrial dynamics with stains that label cell nuclei (Hoechst) and mitochondria (MitoTracker Red) and antibodies that recognize axons (anti-β-tubulinIII), neurons/dendrites (anti-MAP2), dopaminergic neurons/axons (anti-tyrosine hydroxylase; TH), and MSNs (anti-DARPP-32). RESULTS/ANTICIPATED RESULTS: Seeding tubular micro-columns with dopaminergic neuronal aggregates resulted in unidirectional axonal extension, ultimately spanning >5mm by 14 days in vitro. For constructs also seeded with Tissue-engineered, ICC confirmed the presence of the appropriate neuronal sub-types in the two aggregate populations, specifically TH+ dopaminergic neurons and DARPP-32+ MSNs. Moreover, confocal microscopy revealed extensive axonal-dendritic integration and synapse formation involving the dopaminergic axons and MSN somata/dendrites. Collectively, these constructs mimicked the general cytoarchitecture of the in vivo nigrostriatal pathway: a discrete population of dopaminergic neurons with long-projecting 3D axonal tracts that were synaptically integrated with a population of MSNs. Mitochondria structure along axonal tracts was also observed using MitoTracker staining, revealing dynamic intra-axonal mitochondrial motility in this system. Ongoing studies are evaluating real-time mitochondrial dynamics and axonal physiology in this tissue-engineered nigrostriatal pathway in vitro, under both baseline conditions as well as following the addition of exogenous α-Synuclein fibrils to model synucleinopathy in PD. DISCUSSION/SIGNIFICANCE OF IMPACT: This tissue-engineered nigrostriatal pathway provides an anatomically-inspired platform with neuronal-axonal architecture that structurally and functionally emulates the nigrostriatal pathway in vivo. We are applying this paradigm as a powerful in vitro test-bed for understanding mitochondrial activity and inter-axonal energetics pathways under homeostatic as well as PD pathological conditions. Successful demonstration will serve as proof-of-concept that this technique can be used to study mitochondria pathology in personalized constructs built using cells derived from PD patients in order to evaluate pharmacological therapies targeted at improving mitochondrial resiliency and fitness so as to delay and/or prevent dopaminergic axonal/neuronal degeneration in tailored to specific PD patients.
3 - Wireless Intracranial Pressure Systems for the Assessment of Traumatic Brain Injury
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- By Xu Meng, Drexel University, Kevin D. Browne, University of Pennsylvania, D. Kacy Cullen, University of Pennsylvania, Mohammad-Reza Tofighi, Pennsylvania State University, Usmah Kawoos, Naval Medical Research Center, Arye Rosen, Drexel University
- Edited by Isar Mostafanezhad, University of Hawaii, Manoa, Olga Boric-Lubecke, University of Hawaii, Manoa, Jenshan Lin, University of Florida
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- Book:
- Medical and Biological Microwave Sensors and Systems
- Published online:
- 14 December 2017
- Print publication:
- 07 December 2017, pp 89-123
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Summary
A significant reason for death and long-term disability due to head injuries and pathologic conditions is an elevation in the intracranial pressure (ICP) due to vascular compromise and secondary sequelae causing edema. ICP measurements before and after injury in a completely closed-head environment have a significant research value, particularly in the acute postinjury period. With current technology, a tethered fiberoptic probe penetrates the brain and therefore can only remain implanted for relatively short time periods. Use of the probe also can cause complications such as infection and hemorrhage and prohibit immediate (at the time of injury) and long-term measurements of ICP. A small, fully embedded, wireless ICP device may simplify clinical management and research protocols by offering a means for semi-invasive and long-term ICP measurement following brain injury. In this chapter, a new digital wireless ICP (DICP) device is described. The dynamic ICP measurement performances of both the analog ICP (AICP) devices (described in Chapter 2) and the DICP devices are evaluated in a specific traumatic brain injury (TBI) (swine) model of closed-head rotational injury.
Introduction
In Chapter 2, a prototype of an AICP device operating in the industrial-scientific-medical (ISM) band at 2.4 GHz was described that successfully simplified the surgical procedure by reducing the infection rate, the risk of hemorrhage, and the degree of tissue injury.
The AICP device was implanted in a canine model only for a static test, and hypo- and hyperventilation were used to affect variations in ICP. Dynamic ICP variations as a result of TBI in a completely closed-head environment are of paramount importance for understanding the development of a prolonged postconcussion syndrome and facilitating institution of the correct treatment at different stages, particularly in the acute postinjury period. Currently, in experimental (animal) models of TBI, a tethered fiberoptic probe (if inserted before the injury) has to be removed before an injury is induced in order to avoid significant focal damage at the point of probe insertion. Moreover, reinsertion of the probe is possible only after the animal's vital signs have stabilized. However, the act of breaching the cranium after the injury affects the fidelity of the ICP measurements. In addition, proposed noninvasive ICP (NICP) solutions, such as the pulsatility index method based on the use of trancranial Doppler, argued by Figaji et al. [1], have been shown to be insufficient for accurate ICP estimation.
Thin Film Dielectrics for Electronics Using Combustion Chemical Vapor Deposition
- Wen-yi Lin, Hai Huang, D. Kacy Cullen, Shara S. Shoup, Donald Cousins, Jerome J. Schmitt, Andrew T. Hunt, Robert R. Romanofsky, Fred W. VanKeuls, Félix A. Miranda, Carl H. Mueller
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- Journal:
- MRS Online Proceedings Library Archive / Volume 574 / 1999
- Published online by Cambridge University Press:
- 10 February 2011, 371
- Print publication:
- 1999
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This paper reviewed work to date on multicomponent oxides deposited, utilizing openatmosphere Combustion Chemical Vapor Deposition for electronic applications. Epitaxial barium strontium titanate and strontium titanate thin films were deposited on (100) MgO single crystal substrates. They were patterned to form interdigitated structures for electrically tunable devices, namely, coupled microstripline phase shifters (CMPS). The undoped, as-deposited perovskite dielectrics exhibited a figure of merit of 53°/dB at 20 GHz and 23°C, indicating high degree of tunability and fairly low loss. High-permittivity (ε=263), polycrystalline BST and SrTiO3 were studied for dynamic random access memory, and leakage current density of 10−7 A/cm2 was measured. Intended for non-volatile ferroelectric memory, lead zirconium titanate was deposited onto a seed layer of perovskite structure to prevent the growth of the unwanted pyrochlore phase. To function as buffer layers for superconductor applications, epitaxial CeO2, YSZ, SrTiO3, LaAlO3, Y2O3, and Yb2O3 coatings on single crystal and textured nickel substrate were investigated. Electronic analyses and characterization, using SEM, EDS, XRD, and X-ray pole figures, were presented.
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