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- All Subjects: neuroinflammation
- Creators: Stabenfeldt, Sarah
- Member of: Barrett, The Honors College Thesis/Creative Project Collection
Description
Traumatic brain injury (TBI) can result in many pathologies, one of which being coagulopathy. TBI can progress to hemorrhagic lesions and increased intercranial pressure leading to coagulopathy. The coagulopathy has been linked to poor clinical outcomes and occurs in 60% of severe TBI cases. To improve hemostasis, synthetic platelets (SPs) have been repurposed. SPs are composed of a poly(N-isopropylacrylamide-co-acrylic-acid) microgel, conjugated with a fibrin-specific antibody and are biomimetic in their ability to deform and collapse within a fibrin matrix. The objective of this study is to diminish coagulopathy with a single, intravenous injection of SPs, and subsequently decrease neuropathologies. TBI was modeled in animal cohorts using the well-established controlled cortical impact and SPs were injected 2-3 hours post-injury. Control cohorts received no injection. Brain tissue was harvested at acute (24h) and delayed (7 days) time points post-TBI, and fluorescently imaged to quantify reactive astrocytes (GFAP+), microglial morphology and presence (Iba1+), and tissue lesion spared. SP-treatment resulted in significant reduction of GFAP expression at 7 days post-TBI. Furthermore, SP-treatment significantly reduced the percent difference from 24h to 7 days in microglia/macrophage per field compared to the control. For microglial morphology, SP-treated cohorts observed a significant percent difference in endpoints per soma from 24h to 7 days compared to untreated cohorts. However, microglial branch length significantly decreased in percent difference from 24h to 7 days when compared to the control. Finally, tissue sparing did not significantly decrease between 24h and 7 day for SP-treated cohorts as was observed in untreated cohorts, implying inhibition of delayed necrosis. Overall, these results suggest decreased neuroinflammation by 7 days, supporting SPs as potentially therapeutic post-TBI.
ContributorsTodd, Jordan Cecile (Author) / Stabenfeldt, Sarah (Thesis director) / Bharadwaj, Vimala (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Traumatic brain injury (TBI) is a leading cause of death in individuals under the age of 45, resulting in over 50,000 deaths each year. Over 80,000 TBI patients report long-term deficits consisting of motor or cognitive dysfunctions due to TBI pathophysiology. The biochemical secondary injury triggers a harmful inflammatory cascade, gliosis, and astrocyte activation surrounding the injury lesion, and no current treatments exist to alleviate these underlying pathologies. In order to mitigate the negative inflammatory effects of the secondary injury, we created a hydrogel comprised of hyaluronic acid (HA) and laminin, and we hypothesized that the anti-inflammatory properties of HA will decrease astrocyte activation and inflammation after TBI. C57/BL6 mice were subjected to mild-to-moderate CCI. Three days following injury, mice were treated with injection of vehicle or HA-Laminin hydrogel. Mice were sacrificed at three and seven days post injection and analyzed for astrocyte and inflammatory responses. In mice treated with vehicle injections, astrocyte activation was significantly increased at three days post-transplantation in the injured cortex and injury lesion. However, mice treated with the HA-Laminin hydrogel experienced significantly reduced acute astrocyte activation at the injury site three days post transplantation. Interestingly, there were no significant differences in astrocyte activation at seven days post treatment in either group. Although the microglial and macrophage response remains to be investigated, our data suggest that the HA-Laminin hydrogel demonstrates potential for TBI therapeutics targeting inflammation, including acute modulation of the astrocyte, microglia, and macrophage response to TBI.
ContributorsGoddery, Emma Nicole (Author) / Stabenfeldt, Sarah (Thesis director) / Addington, Caroline (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Neurological disorders are difficult to treat with current drug delivery methods due to their inefficiency and the lack of knowledge of the mechanisms behind drug delivery across the blood brain barrier (BBB). Nanoparticles (NPs) are a promising drug delivery method due to their biocompatibility and ability to be modified by cell penetrating peptides, such as transactivating transciptor (TAT) peptide, which has been shown to increase efficiency of delivery. There are multiple proposed mechanisms of TAT-mediated delivery that also have size restrictions on the molecules that can undergo each BBB crossing mechanism. The effect of nanoparticle size on TAT-mediated delivery in vivo is an important aspect to research in order to better understand the delivery mechanisms and to create more efficient NPs. NPs called FluoSpheres are used because they come in defined diameters unlike polymeric NPs that have a broad distribution of diameters. Both modified and unmodified 100nm and 200nm NPs were able to bypass the BBB and were seen in the brain, spinal cord, liver, and spleen using confocal microscopy and a biodistribution study. Statistically significant differences in delivery rate of the different sized NPs or between TAT-modified and unmodified NPs were not found. Therefore in future work a larger range of diameter size will be evaluated. Also the unmodified NPs will be conjugated with scrambled peptide to ensure that both unmodified and TAT-modified NPs are prepared in identical fashion to better understand the role of size on TAT targeting. Although all the NPs were able to bypass the BBB, future work will hopefully provide a better representation of how NP size effects the rate of TAT-mediated delivery to the CNS.
ContributorsCeton, Ricki Ronea (Author) / Stabenfeldt, Sarah (Thesis director) / Sirianni, Rachael (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Traumatic brain injury (TBI) poses a significant global health concern with substantial health and economic consequences. Patients often face significant consequences after injury, notably persistent cognitive changes and an increased risk of developing neurodegenerative disease later in life. Apart from the immediate insult, the resulting inflammatory response can lead to neuroinflammation, oxidative stress, tissue death, and long-term neurodegeneration. Microglia and astrocytes play critical roles in these inflammatory processes, emphasizing the unmet need for targeted therapies. Vaccine formulations consisting of poly (a-ketoglutarate) (paKG) microparticles (MPs) encapsulating PFK15 (1-(4-pyridinyl)-3-(2-quinolinyl)-2-propen-1-one) and myelin proteolipid protein (PLP) were developed for prior studies and have demonstrated the production of antigen-specific adaptive T-cell responses in the brain, spleen, and lymph nodes of mice, suggesting that these formulations may be able to prevent neuronal inflammation in mice after TBI. The vaccine efficacy was further evaluated through the image analysis of immunohistochemically stained brain tissue sections from naive, saline, and paKG(PFK15+PLP) MPs or paKG(PFK15) MPs treated mice. Though microglia (Iba1), astrocytes (GFAP) and CD86 were visualized in this method, only Iba1 was found to be significantly reduced in the contralateral hemisphere for paKG(PFK15+PLP) MPs and paKG(PFK15) MPs groups when compared to naive (p=0.0373 and p=0.0186, respectively). However, the naive group also showed an unexpectedly high level of CD86 after thresholding (compared to the TBI groups), indicating flaws were present in the analysis pipeline. Challenges of the image analysis process included thresholding setting optimization, folded tissues, bubbles, and saturated punctate signal. These issues may have impacted data accuracy, underscoring the need for rigorous optimization of experimental techniques and imaging methodologies when evaluating the therapeutic potential of the vaccines in mitigating TBI-induced neuroinflammation. Thus, future analyses should consider microglial morphology and employ more accurate thresholding in FIJI/ImageJ to better measure cellular activation and the overall positive signal.
ContributorsSundem, Andrea (Author) / Stabenfeldt, Sarah (Thesis director) / Willingham, Crystal (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2024-05