Publications by authors named "Kelly M Scheulin"

7 Publications

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Intracisternal administration of tanshinone IIA-loaded nanoparticles leads to reduced tissue injury and functional deficits in a porcine model of ischemic stroke.

IBRO Neurosci Rep 2021 Jun 5;10:18-30. Epub 2021 Jan 5.

Regenerative Bioscience Center, University of Georgia, Athens, GA 30602, United States.

Background: The absolute number of new stroke patients is annually increasing and there still remains only a few Food and Drug Administration (FDA) approved treatments with significant limitations available to patients. Tanshinone IIA (Tan IIA) is a promising potential therapeutic for ischemic stroke that has shown success in pre-clinical rodent studies but lead to inconsistent efficacy results in human patients. The physical properties of Tan-IIA, including short half-life and low solubility, suggests that Poly (lactic-co-glycolic acid) (PLGA) nanoparticle-assisted delivery may lead to improve bioavailability and therapeutic efficacy. The objective of this study was to develop Tan IIA-loaded nanoparticles (Tan IIA-NPs) and to evaluate their therapeutic effects on cerebral pathological changes and consequent motor function deficits in a pig ischemic stroke model.

Results: Tan IIA-NP treated neural stem cells showed a reduction in SOD activity in in vitro assays demonstrating antioxidative effects. Ischemic stroke pigs treated with Tan IIA-NPs showed reduced hemispheric swelling when compared to vehicle only treated pigs (7.85 ± 1.41 vs. 16.83 ± 0.62%), consequent midline shift (MLS) (1.72 ± 0.07 vs. 2.91 ± 0.36 mm), and ischemic lesion volumes (9.54 ± 5.06 vs. 12.01 ± 0.17 cm) when compared to vehicle-only treated pigs. Treatment also lead to lower reductions in diffusivity (-37.30 ± 3.67 vs. -46.33 ± 0.73%) and white matter integrity (-19.66 ± 5.58 vs. -30.11 ± 1.19%) as well as reduced hemorrhage (0.85 ± 0.15 vs 2.91 ± 0.84 cm) 24 h post-ischemic stroke. In addition, Tan IIA-NPs led to a reduced percentage of circulating band neutrophils at 12 (7.75 ± 1.93 vs. 14.00 ± 1.73%) and 24 (4.25 ± 0.48 vs 5.75 ± 0.85%) hours post-stroke suggesting a mitigated inflammatory response. Moreover, spatiotemporal gait deficits including cadence, cycle time, step time, swing percent of cycle, stride length, and changes in relative mean pressure were less severe post-stroke in Tan IIA-NP treated pigs relative to control pigs.

Conclusion: The findings of this proof of concept study strongly suggest that administration of Tan IIA-NPs in the acute phase post-stroke mitigates neural injury likely through limiting free radical formation, thus leading to less severe gait deficits in a translational pig ischemic stroke model. With stroke as one of the leading causes of functional disability in the United States, and gait deficits being a major component, these promising results suggest that acute Tan IIA-NP administration may improve functional outcomes and the quality of life of many future stroke patients.
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http://dx.doi.org/10.1016/j.ibneur.2020.11.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8019951PMC
June 2021

Exploring the predictive value of lesion topology on motor function outcomes in a porcine ischemic stroke model.

Sci Rep 2021 Feb 15;11(1):3814. Epub 2021 Feb 15.

Regenerative Bioscience Center, University of Georgia, Athens, GA, USA.

Harnessing the maximum diagnostic potential of magnetic resonance imaging (MRI) by including stroke lesion location in relation to specific structures that are associated with particular functions will likely increase the potential to predict functional deficit type, severity, and recovery in stroke patients. This exploratory study aims to identify key structures lesioned by a middle cerebral artery occlusion (MCAO) that impact stroke recovery and to strengthen the predictive capacity of neuroimaging techniques that characterize stroke outcomes in a translational porcine model. Clinically relevant MRI measures showed significant lesion volumes, midline shifts, and decreased white matter integrity post-MCAO. Using a pig brain atlas, damaged brain structures included the insular cortex, somatosensory cortices, temporal gyri, claustrum, and visual cortices, among others. MCAO resulted in severely impaired spatiotemporal gait parameters, decreased voluntary movement in open field testing, and higher modified Rankin Scale scores at acute timepoints. Pearson correlation analyses at acute timepoints between standard MRI metrics (e.g., lesion volume) and functional outcomes displayed moderate R values to functional gait outcomes. Moreover, Pearson correlation analyses showed higher R values between functional gait deficits and increased lesioning of structures associated with motor function, such as the putamen, globus pallidus, and primary somatosensory cortex. This correlation analysis approach helped identify neuroanatomical structures predictive of stroke outcomes and may lead to the translation of this topological analysis approach from preclinical stroke assessment to a clinical biomarker.
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http://dx.doi.org/10.1038/s41598-021-83432-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7884696PMC
February 2021

Magnetic Resonance Imaging and Gait Analysis Indicate Similar Outcomes Between Yucatan and Landrace Porcine Ischemic Stroke Models.

Front Neurol 2020 21;11:594954. Epub 2021 Jan 21.

Regenerative Bioscience Center, University of Georgia, Athens, GA, United States.

The Stroke Therapy Academic Industry Roundtable (STAIR) has recommended that novel therapeutics be tested in a large animal model with similar anatomy and physiology to humans. The pig is an attractive model due to similarities in brain size, organization, and composition relative to humans. However, multiple pig breeds have been used to study ischemic stroke with potentially differing cerebral anatomy, architecture and, consequently, ischemic stroke pathologies. The objective of this study was to characterize brain anatomy and assess spatiotemporal gait parameters in Yucatan (YC) and Landrace (LR) pigs pre- and post-stroke using magnetic resonance imaging (MRI) and gait analysis, respectively. Ischemic stroke was induced via permanent middle cerebral artery occlusion (MCAO). MRI was performed pre-stroke and 1-day post-stroke. Structural and diffusion-tensor sequences were performed at both timepoints and analyzed for cerebral characteristics, lesion diffusivity, and white matter changes. Spatiotemporal and relative pressure gait measurements were collected pre- and 2-days post-stroke to characterize and compare acute functional deficits. The results from this study demonstrated that YC and LR pigs exhibit differences in gross brain anatomy and gait patterns pre-stroke with MRI and gait analysis showing statistical differences in the majority of parameters. However, stroke pathologies in YC and LR pigs were highly comparable post-stroke for most evaluated MRI parameters, including lesion volume and diffusivity, hemisphere swelling, ventricle compression, caudal transtentorial and foramen magnum herniation, showing no statistical difference between the breeds. In addition, post-stroke changes in velocity, cycle time, swing percent, cadence, and mean hoof pressure showed no statistical difference between the breeds. These results indicate significant differences between pig breeds in brain size, anatomy, and motor function pre-stroke, yet both demonstrate comparable brain pathophysiology and motor outcomes post-stroke. The conclusions of this study suggest pigs of these different breeds generally show a similar ischemic stroke response and findings can be compared across porcine stroke studies that use different breeds.
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http://dx.doi.org/10.3389/fneur.2020.594954DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7859633PMC
January 2021

Semi-Automated Cell and Tissue Analyses Reveal Regionally Specific Morphological Alterations of Immune and Neural Cells in a Porcine Middle Cerebral Artery Occlusion Model of Stroke.

Front Cell Neurosci 2020 22;14:600441. Epub 2021 Jan 22.

Regenerative Bioscience Center, University of Georgia, Athens, GA, United States.

Histopathological analysis of cellular changes in the stroked brain provides critical information pertaining to inflammation, cell death, glial scarring, and other dynamic injury and recovery responses. However, commonly used manual approaches are hindered by limitations in speed, accuracy, bias, and the breadth of morphological information that can be obtained. Here, a semi-automated high-content imaging (HCI) and CellProfiler histological analysis method was developed and used in a Yucatan miniature pig permanent middle cerebral artery occlusion (pMCAO) model of ischemic stroke to overcome these limitations. Evaluation of 19 morphological parameters in IBA1 microglia/macrophages, GFAP astrocytes, NeuN neuronal, FactorVIII vascular endothelial, and DCX neuroblast cell areas was conducted on porcine brain tissue 4 weeks post pMCAO. Out of 19 morphological parameters assessed in the stroke perilesional and ipsilateral hemisphere regions (38 parameters), a significant change in measured IBA1 parameters, GFAP parameters, NeuN parameters, FactorVIII parameters, and DCX parameters were observed in stroked vs. non-stroked animals. Principal component analysis (PCA) and correlation analyses demonstrated that stroke-induced significant and predictable morphological changes that demonstrated strong relationships between IBA1, GFAP, and NeuN areas. Ultimately, this unbiased, semi-automated HCI and CellProfiler histopathological analysis approach revealed regional and cell specific morphological signatures of immune and neural cells after stroke in a highly translational porcine model. These identified features can provide information of disease pathogenesis and evolution with high resolution, as well as be used in therapeutic screening applications.
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http://dx.doi.org/10.3389/fncel.2020.600441DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7862775PMC
January 2021

Dynamic Changes in the Gut Microbiome at the Acute Stage of Ischemic Stroke in a Pig Model.

Front Neurosci 2020 3;14:587986. Epub 2020 Dec 3.

Department of Foods and Nutrition, College of Family and Consumer Sciences, University of Georgia, Athens, GA, United States.

Stroke is a major cause of death and long-term disability affecting seven million adults in the United States each year. Recently, it has been demonstrated that neurological diseases, associated pathology, and susceptibility changes correlated with changes in the gut microbiota. However, changes in the microbial community in stroke has not been well characterized. The acute stage of stroke is a critical period for assessing injury severity, therapeutic intervention, and clinical prognosis. We investigated the changes in the gut microbiota composition and diversity using a middle cerebral artery (MCA) occlusion ischemic stroke pig model. Ischemic stroke was induced by cauterization of the MCA in pigs. Blood samples were collected prestroke and 4 h, 12 h, 1 day, and 5 days poststroke to evaluate circulating proinflammatory cytokines. Fecal samples were collected prestroke and 1, 3, and 5 days poststroke to assess gut microbiome changes. Results showed elevated systemic inflammation with increased plasma levels of tumor necrosis factor alpha at 4 h and interleukin-6 at 12 h poststroke, relative to prestroke. Microbial diversity and evenness were reduced at 1 day poststroke compared to prestroke. Microbial diversity at 3 days poststroke was negatively correlated with lesion volume. Moreover, beta-diversity analysis revealed trending overall differences over time, with the most significant changes in microbial patterns observed between prestroke and 3 days poststroke. Abundance of the Proteobacteria was significantly increased, while Firmicutes decreased at 3 days poststroke, compared to prestroke populations. Abundance of the lactic acid bacteria was reduced at 3 days poststroke. By day 5, the microbial pattern returned to similar values as prestroke, suggesting the plasticity of gut microbiome in an acute period of stroke in a pig model. These findings provide a basis for characterizing gut microbial changes during the acute stage of stroke, which can be used to assess stroke pathology and the potential development of therapeutic targets.
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http://dx.doi.org/10.3389/fnins.2020.587986DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7744295PMC
December 2020

An integrative multivariate approach for predicting functional recovery using magnetic resonance imaging parameters in a translational pig ischemic stroke model.

Neural Regen Res 2021 May;16(5):842-850

Regenerative Bioscience Center; Neuroscience, Biomedical and Health Sciences Institute; Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, USA.

Magnetic resonance imaging (MRI) is a clinically relevant, real-time imaging modality that is frequently utilized to assess stroke type and severity. However, specific MRI biomarkers that can be used to predict long-term functional recovery are still a critical need. Consequently, the present study sought to examine the prognostic value of commonly utilized MRI parameters to predict functional outcomes in a porcine model of ischemic stroke. Stroke was induced via permanent middle cerebral artery occlusion. At 24 hours post-stroke, MRI analysis revealed focal ischemic lesions, decreased diffusivity, hemispheric swelling, and white matter degradation. Functional deficits including behavioral abnormalities in open field and novel object exploration as well as spatiotemporal gait impairments were observed at 4 weeks post-stroke. Gaussian graphical models identified specific MRI outputs and functional recovery variables, including white matter integrity and gait performance, that exhibited strong conditional dependencies. Canonical correlation analysis revealed a prognostic relationship between lesion volume and white matter integrity and novel object exploration and gait performance. Consequently, these analyses may also have the potential of predicting patient recovery at chronic time points as pigs and humans share many anatomical similarities (e.g., white matter composition) that have proven to be critical in ischemic stroke pathophysiology. The study was approved by the University of Georgia (UGA) Institutional Animal Care and Use Committee (IACUC; Protocol Number: A2014-07-021-Y3-A11 and 2018-01-029-Y1-A5) on November 22, 2017.
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http://dx.doi.org/10.4103/1673-5374.297079DOI Listing
May 2021

Characterization of tissue and functional deficits in a clinically translational pig model of acute ischemic stroke.

Brain Res 2020 06 16;1736:146778. Epub 2020 Mar 16.

Regenerative Bioscience Center, University of Georgia, Athens, GA, United States; Neuroscience Program, Biomedical and Health Sciences Institute, University of Georgia, Athens, GA, United States; Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, United States. Electronic address:

The acute stroke phase is a critical time frame used to evaluate stroke severity, therapeutic options, and prognosis while also serving as a major tool for the development of diagnostics. To further understand stroke pathophysiology and to enhance the development of treatments, our group developed a translational pig ischemic stroke model. In this study, the evolution of acute ischemic tissue damage, immune responses, and functional deficits were further characterized. Stroke was induced by middle cerebral artery occlusion in Landrace pigs. At 24 h post-stroke, magnetic resonance imaging revealed a decrease in ipsilateral diffusivity, an increase in hemispheric swelling resulting in notable midline shift, and intracerebral hemorrhage. Stroke negatively impacted white matter integrity with decreased fractional anisotropy values in the internal capsule. Like patients, pigs showed a reduction in circulating lymphocytes and a surge in neutrophils and band cells. Functional responses corresponded with structural changes through reductions in open field exploration and impairments in spatiotemporal gait parameters. Characterization of acute ischemic stroke in pigs provided important insights into tissue and functional-level assessments that could be used to identify potential biomarkers and improve preclinical testing of novel therapeutics.
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http://dx.doi.org/10.1016/j.brainres.2020.146778DOI Listing
June 2020