Injured Hemisphere Research Articles

Precisely targeted drug delivery by mesenchymal stem cells-based biomimetic liposomes to cerebral ischemia-reperfusion injured hemisphere

The precise and targeted delivery of therapeutic agents to the lesion sites remains a major challenge in treating brain diseases represented by ischemic stroke. Herein, we modified liposomes with mesenchymal stem cells (MSC) membrane to construct biomimetic liposomes, termed MSCsome. MSCsome (115.99 ± 4.03 nm) exhibited concentrated accumulation in the cerebral infarcted hemisphere of mice with cerebral ischemia-reperfusion injury, while showing uniform distribution in the two cerebral hemispheres of normal mice. Moreover, MSCsome exhibited high colocalization with damaged nerve cells in the infarcted hemisphere, highlighting its advantageous precise targeting capabilities over liposomes at both the tissue and cellular levels. Leveraging its superior targeting properties, MSCsome effectively delivered Dl-3-n-butylphthalide (NBP) to the injured hemisphere, making a single-dose (15 mg/kg) intravenous injection of NBP-encapsulated MSCsome facilitate the recovery of motor functions in model mice by improving the damaged microenvironment and suppressing neuroinflammation. This study underscores that the modification of the MSC membrane notably enhances the capacity of liposomes for precisely targeting the injured hemisphere, which is particularly crucial in treating cerebral ischemia-reperfusion injury.

Brain metabolism after therapeutic hypothermia for murine hypoxia-ischemia using hyperpolarized [1-13C] pyruvate magnetic resonance spectroscopy.

Hypoxic-ischemic encephalopathy (HIE) is a common neurological syndrome in newborns with high mortality and morbidity. Therapeutic hypothermia (TH), which is standard of care for HIE, mitigates brain injury by suppressing anaerobic metabolism. However, more than 40% of HIE neonates have a poor outcome, even after TH. This study aims to provide metabolic biomarkers for predicting the outcomes of hypoxia-ischemia (HI) after TH using hyperpolarized [1-13C] pyruvate magnetic resonance spectroscopy. Postnatal day 10 (P10) mice with HI underwent TH at 1 h and were scanned at 6-8 h (P10), 24 h (P11), 7 days (P17), and 21 days (P31) post-HI on a 14.1-T NMR spectrometer. The metabolic images were collected, and the conversion rate from pyruvate to lactate and the ratio of lactate to pyruvate in the injured left hemisphere (kPL(L) and Lac/Pyr(L), respectively) were calculated at each timepoint. The outcomes of TH were determined by the assessments of brain injury on T2-weighted images and behavioral tests at later timepoint. kPL(L) and Lac/Pyr(L) over time between the good-outcome and poor-outcome groups and across timepoints within groups were analyzed. We found significant differences in temporal trends of kPL(L) and Lac/Pyr(L) between groups. In the good-outcome group, kPL(L) increased until P31 with a significantly higher value at P31 compared with that at P10, while the level of Lac/Pyr(L) at P31 was notably higher than those at all other timepoints. In the poor-outcome group, kPL(L) and Lac/Pyr(L) increased within 24 h. The kPL(L) value at P11 was considerably higher compared with P10. Discrete temporal changes of kPL(L) and Lac/Pyr(L) after TH between the good-outcome and poor-outcome groups were seen as early as 24 h after HI, reflecting various TH effects on brain anaerobic metabolism, which may provide insights for early screening for response to TH.

108 A Translational Approach to Suppress Local Inflammation in the Ischemic Penumbra and Deliver Local Anti-platelet Activity After Stroke

INTRODUCTION: Mechanical thrombectomy is the standard of care for ischemic stroke, but there is a significant mismatch between successful recanalization and clinical outcomes. Inflammation in the ischemic penumbra remains a target for neuroprotective interventions even in recanalized and non-recanalized patients. P-selectin (Psel) is a marker of endothelial cell activation and could be used to deliver therapeutics locally to the site of ischemic injury. METHODS: The fusion protein Pselectin-Crry was constructed using single chain antibody sequence linked to the extracellular region of mouse Crry. In-vivo testing using surface plasmon resonance for binding affinity to Psel, and zymosan assay for complement inhibitory activity. In-vivo studies were performed in C57bl/6 mice subjected to transient middle cerebral artery occlusion for 1 hour followed by administration of Psel-Crry 2 hours after reperfusion. Psel-Crry was labelled using far-red fluorescence and live-animal imaging was used to study brain-specific targeting. The modified Neurological Severity (NS) score was used for functional outcome along with survival, infarct volume and histological outcomes. RESULTS: Psel-Crry demonstrated dose-dependent complement inhibitory activity, and localized specifically to the stroke brain on in-vivo live imaging. Ex-vivo imaging of explanted brain showed Psel-Crry binding specifically to the injured hemisphere without off-target binding (Stroke vs. Sham, p < 0.001). Psel-Crry resulted in 60% reduction in infarct volume at 3 days compare to vehicle (N = 8/group, p < 0.05), reduction in NS scores compared to vehicle (Median 3 vs. 1.5, p < 0.05), and improved 1-week survival (80% vs. 50%, p < 0.05). Histological analyses demonstrated preservation of dendritic arborization in the ischemic penumbra with Psel-Crry treatment with concurrent significant reduction in microglial activation. CONCLUSIONS: Psel-Crry is a translational agent that can achieve local complement inhibitory effect and antiplatelet activity after stroke and has promise for potential use as ajuvant therapy in stroke.

Complications of Intracranial Multimodal Monitoring for Neurocritical Care: A Systematic Review and Meta-Analysis.

Intracranial multimodal monitoring (iMMM) is increasingly used for neurocritical care. However, concerns arise regarding iMMM invasiveness considering limited evidence in its clinical significance and safety profile. We conducted a synthesis of evidence regarding complications associated with iMMM to delineate its safety profile. We performed a systematic review and meta-analysis (PROSPERO Registration Number: CRD42021225951) according to the Preferred Reporting Items for Systematic Review and Meta-Analysis and Peer Review of Electronic Search Strategies guidelines to retrieve evidence from studies reporting iMMM use in humans that mention related complications. We assessed risk of bias using the Newcastle-Ottawa Scale and funnel plots. The primary outcomes were iMMM complications. The secondary outcomes were putative risk factors. Of the 366 screened articles, 60 met the initial criteria and were further assessed by full-text reading. We included 22 studies involving 1206 patients and 1434 iMMM placements. Most investigators used a bolt system (85.9%) and a three-lumen device (68.8%), mainly inserting iMMM into the most injured hemisphere (77.9%). A total of 54 postoperative intracranial hemorrhages (pooled rate of 4%; 95% confidence interval [CI] 0-10%; I2 86%, p < 0.01 [random-effects model]) was reported, along with 46 misplacements (pooled rate of 6%; 95% CI 1-12%; I2 78%, p < 0.01) and 16 central nervous system infections (pooled rate of 0.43%; 95% CI 0-2%; I2 64%, p < 0.01). We found 6 system breakings, 18 intracranial bone fragments, and 5 cases of pneumocephalus. Currently, iMMM systems present a similar safety profile as intracranial devices commonly used in neurocritical care. Long-term outcomes of prospective studies will complete the benefit-risk assessment of iMMM in neurocritical care. Consensus-based reporting guidelines on iMMM use are needed to bolster future collaborative efforts.

Effect of aging on the cerebral metabolic mechanism of electroacupuncture treatment in rats with traumatic brain injury.

Aging has great influence on the clinical treatment effect of cerebrovascular diseases, and evidence suggests that the effect may be associated with age-related brain plasticity. Electroacupuncture is an effective alternative treatment for traumatic brain injury (TBI). In the present study, we aimed to explore the effect of aging on the cerebral metabolic mechanism of electroacupuncture to provide new evidence for developing age-specific rehabilitation strategies. Both aged (18 months) and young (8 weeks) rats with TBI were analyzed. Thirty-two aged rats were randomly divided into four groups: aged model, aged electroacupuncture, aged sham electroacupuncture, and aged control group. Similarly, 32 young rats were also divided into four groups: young model, young electroacupuncture, young sham electroacupuncture, and young control group. Electroacupuncture was applied to "Bai hui" (GV20) and "Qu chi" (LI11) for 8 weeks. CatWalk gait analysis was then performed at 3 days pre- and post-TBI, and at 1, 2, 4, and 8 weeks after intervention to observe motor function recovery. Positron emission computed tomography (PET/CT) was performed at 3 days pre- and post-TBI, and at 2, 4, and 8 weeks after intervention to detect cerebral metabolism. Gait analysis showed that electroacupuncture improved the forepaw mean intensity in aged rats after 8 weeks of intervention, but after 4 weeks of intervention in young rats. PET/CT revealed increased metabolism in the left (the injured ipsilateral hemisphere) sensorimotor brain areas of aged rats during the electroacupuncture intervention, and increased metabolism in the right (contralateral to injury hemisphere) sensorimotor brain areas of young rats. This study demonstrated that aged rats required a longer electroacupuncture intervention duration to improve motor function than that of young rats. The influence of aging on the cerebral metabolism of electroacupuncture treatment was mainly focused on a particular hemisphere.

Intranasally administered human MSC-derived extracellular vesicles inhibit NLRP3-p38/MAPK signaling after TBI and prevent chronic brain dysfunction

Traumatic brain injury (TBI) leads to lasting brain dysfunction with chronic neuroinflammation typified by nucleotide-binding domain leucine-rich repeat and pyrin domain-containing receptor 3 (NLRP3) inflammasome activation in microglia. This study probed whether a single intranasal (IN) administration of human mesenchymal stem cell-derived extracellular vesicles (hMSC-EVs) naturally enriched with activated microglia-modulating miRNAs can avert chronic adverse outcomes of TBI. Small RNA sequencing confirmed the enrichment of miRNAs capable of modulating activated microglia in hMSC-EV cargo. IN administration of hMSC-EVs into adult mice ninety minutes after the induction of a unilateral controlled cortical impact injury resulted in their incorporation into neurons and microglia in both injured and contralateral hemispheres. A single higher dose hMSC-EV treatment also inhibited NLRP3 inflammasome activation after TBI, evidenced by reduced NLRP3, apoptosis-associated speck-like protein containing a CARD, activated caspase-1, interleukin-1 beta, and IL-18 levels in the injured brain. Such inhibition in the acute phase of TBI endured in the chronic phase, which could also be gleaned from diminished NLRP3 inflammasome activation in microglia of TBI mice receiving hMSC-EVs. Proteomic analysis and validation revealed that higher dose hMSC-EV treatment thwarted the chronic activation of the p38 mitogen-activated protein kinase (MAPK) signaling pathway by IL-18, which decreased the release of proinflammatory cytokines. Inhibition of the chronic activation of NLRP3-p38/MAPK signaling after TBI also prevented long-term cognitive and mood impairments. Notably, the animals receiving higher doses of hMSC-EVs after TBI displayed better cognitive and mood function in all behavioral tests than animals receiving the vehicle after TBI. A lower dose of hMSC-EV treatment also partially improved cognitive and mood function. Thus, an optimal IN dose of hMSC-EVs naturally enriched with activated microglia-modulating miRNAs can inhibit the chronic activation of NLRP3-p38/MAPK signaling after TBI and prevent lasting brain dysfunction.

The pericontused cortex can support function early after TBI but it remains functionally isolated from normal afferent input

Traumatically injured brain functional connectivity (FC) is altered in a region-dependent manner with some regions functionally disconnected while others are hyperconnected after experimental TBI. Remote, homotopic cortical regions become hyperexcitable after injury, and we hypothesize that this results in increased trans-hemispheric cortical inhibition, preventing reorganization of the primary injured hemisphere. Previously we have shown that temporary silencing the contralesional cortex at 1wk normalizes affected forelimb behavioral use, but not at 4wks. To investigate the potential mechanism for this and to determine whether this occurs due to restoration of afferent pathway FC, and/or reorganization of brain circuits, we probed forelimb circuit function with sensorimotor task-evoked-fMRI, resting state fMRI seed-based analysis, and exploratory structural equation modelling (SEM) of directed causal connections due to forelimb task at 1 and 4wks post-injury after temporary, contralateral silencing with intraparenchymal injection of muscimol versus vehicle, as well as from sham rats. As predicted, silencing at 1wk and 4wks post-injury decimated the contralesional cortical forelimb map evoked by stimulation of the opposite, unaffected forelimb compared to vehicle-injected injured rats indicating the success of the intervention. Surprisingly however, this also resulted in activation of the pericontused cortex ipsilateral to the stimulated forelimb at 1wk, yet this same region could not be activated by directly stimulating the opposite, injury-affected forelimb. Underpinning this were significant increases in interhemispheric FC at the level of the cortex but decreases within subcortical regions. Causal SEM analysis confirmed increased corticothalamic connectivity and suggested changes from and to bilateral thalamus are important for the effect. At 4wks post-injury only cortical increases in FC were found in response to silencing indicating a less flexible brain, and ipsilesional cortex evoked activity was mostly absent. The absence of a reinstatement of ipsilesional evoked activity through normal pathways by temporary neuromodulation despite prior data showing behavioral improvements under the same conditions, indicates that while the pericontused cortex does retain function initially after injury, it is too functionally disconnected to be controlled by normal afferent input. More significant alterations in cross-brain FC during neuromodulation at 1wk compared to 4wk post-injury, suggest that more distributed brain activity accounts for prior behavior improvements in sensorimotor function, and that hemispheric imbalance in function is causally involved in early loss of sensorimotor function in this TBI model.

In-depth characterization of a mouse model of post-traumatic epilepsy for biomarker and drug discovery

Post-traumatic epilepsy (PTE) accounts for 5% of all epilepsies and 10–20% of the acquired forms. The latency between traumatic brain injury (TBI) and epilepsy onset in high-risk patients offers a therapeutic window for intervention to prevent or improve the disease course. However, progress towards effective treatments has been hampered by the lack of sensitive prognostic biomarkers of PTE, and of therapeutic targets. There is therefore a pressing clinical need for preclinical PTE models suitable for biomarker discovery and drug testing. We characterized in-depth a model of severe TBI induced by controlled cortical impact evolving into PTE in CD1 adult male mice. To identify sensitive measures predictive of PTE development and severity, TBI mice were longitudinally monitored by video-electrocorticography (ECoG), examined by MRI, and tested for sensorimotor and cognitive deficits and locomotor activity. At the end of the video-ECoG recording mice were killed for brain histological analysis. PTE occurred in 58% of mice with frequent motor seizures (one seizure every other day), as determined up to 5 months post-TBI. The weight loss of PTE mice in 1 week after TBI correlated with the number of spontaneous seizures at 5 months. Moreover, the recovery rate of the sensorimotor deficit detected by the SNAP test before the predicted time of epilepsy onset was significantly lower in PTE mice than in those without epilepsy. Neuroscore, beam walk and cognitive deficit were similar in all TBI mice. The increase in the contusion volume, the volume of forebrain regions contralateral to the lesioned hemisphere and white matter changes over time assessed by MRI were similar in PTE and no-PTE mice. However, brain histology showed a more pronounced neuronal cell loss in the cortex and hippocampus contralateral to the injured hemisphere in PTE than in no-PTE mice. The extensive functional and neuropathological characterization of this TBI model, provides a tool to identify sensitive measures of epilepsy development and severity clinically useful for increasing PTE prediction in high-risk TBI patients. The high PTE incidence and spontaneous seizures frequency in mice provide an ideal model for biomarker discovery and for testing new drugs.

Neurophysiological prognostic factors of motor function and spasticity after stroke

Purpose: Understanding the neural mechanisms of recovery of motor control and development of spasticity after stroke is paramount importance for neurorehabilitation.Methods: For this purpose, we have analyzed several TMS and EEG variables and their association with motor recovery and development of spasticity. Forty-two subjects with stroke have taken part in the investigation. The neurophysiological examination included assessments by transcranial magnetic stimulation (TMS), intra- and inter-hemispheric EEG coherence in different frequency bands (e.g. Theta (4.0–7.99 Hz)) as determined by quantitative electroencephalography (qEEG). Motor function has been measured by Fugl-Meyer (FM), spasticity has been measured by modified Ashworth scale. Multiple univariate and multivariate linear regression analyses have been performed to identify the predictors for motor function and spasticity.Results: Univariate analyses have shown a significant interaction of amplitude and motor threshold (MT) of injured and MT, central motor conduction time of uninjured hemisphere with motor function according to Fugle-Meyer (FM). Also significant interaction has been shown between MT of injured hemisphere and spasticity.Multivariate analyses have shown a significant interaction of MT and beta coherence in injured, uninjured hemisphere and interhemispheric in prediction of motor function by FM. Also significant interaction of MT of injured hemisphere, delta and theta coherence between C3-C4 and spasticity has been shown.These interaction suggests that higher beta activity in the lesioned hemisphere strengthens the association between MT and FM scores. Higher beta activity in the uninjured hemisphere strengthens the association between MT and FM scores. Higher interhemispheric beta activity between C3-C4 strengthens the association between MT and FM scores. Higher delta and theta interhemispheric activity between C3-C4 strengthens the association between MT and Ashworth scores.Conclusions: Our results suggest that MT of both hemispheres is the strongest predictors of motor recovery after stroke. Moreover, cortical activity in the injured and uninjured hemisphere measured by qEEG provides additional information, specifying the association between MT and FM scores. MT of injured hemisphere in the association with low-frequency cortical activity are the strongest predictors of spasticity after stroke.Thus, the combination of EEG and TMS in predicting the recovery of motor control after stroke provides additional opportunities in the study of nonlinear relationships of influencing the interhemispheric networks, uninjured hemisphere and the release of subcortical activity

An In Vivo Study of a Rat Fluid-Percussion-Induced Traumatic Brain Injury Model with [11C]PBR28 and [18F]flumazenil PET Imaging.

Traumatic brain injury (TBI) modelled by lateral fluid percussion-induction (LFPI) in rats is a widely used experimental rodent model to explore and understand the underlying cellular and molecular alterations in the brain caused by TBI in humans. Current improvements in imaging with positron emission tomography (PET) have made it possible to map certain features of TBI-induced cellular and molecular changes equally in humans and animals. The PET imaging technique is an apt supplement to nanotheranostic-based treatment alternatives that are emerging to tackle TBI. The present study aims to investigate whether the two radioligands, [11C]PBR28 and [18F]flumazenil, are able to accurately quantify in vivo molecular-cellular changes in a rodent TBI-model for two different biochemical targets of the processes. In addition, it serves to observe any palpable variations associated with primary and secondary injury sites, and in the affected versus the contralateral hemispheres. As [11C]PBR28 is a radioligand of the 18 kD translocator protein, the up-regulation of which is coupled to the level of neuroinflammation in the brain, and [18F]flumazenil is a radioligand for GABAA-benzodiazepine receptors, whose level mirrors interneuronal activity and eventually cell death, the use of the two radioligands may reveal two critical features of TBI. An up-regulation in the [11C]PBR28 uptake triggered by the LFP in the injured (right) hemisphere was noted on day 14, while the uptake of [18F]flumazenil was down-regulated on day 14. When comparing the left (contralateral) and right (LFPI) hemispheres, the differences between the two in neuroinflammation were obvious. Our results demonstrate a potential way to measure the molecular alterations in a rodent-based TBI model using PET imaging with [11C]PBR28 and [18F]flumazenil. These radioligands are promising options that can be eventually used in exploring the complex in vivo pharmacokinetics and delivery mechanisms of nanoparticles in TBI treatment.

Quantitative Electroencephalography After Pediatric Anterior Circulation Stroke.

Regional differences were investigated in quantitative EEG (QEEG) characteristics and associations of QEEG to hemodynamics after pediatric acute stroke. Quantitative EEG was analyzed, including power in delta, theta, alpha, and beta bands, alpha-delta power ratio, total power, and spectral edge frequency from 11 children with unilateral, anterior circulation strokes during the first 24 hours of continuous EEG recording. Differences between injured and uninjured hemispheres were assessed using multivariate dynamic structural equations modeling. Dynamic structural equations modeling was applied to six children with hemorrhagic stroke undergoing arterial blood pressure, heart rate, and cerebral oximetry monitoring to investigate associations between hemodynamics with QEEG adjacent to anterior circulation regions. All patients with acute ischemic stroke ( n = 5) had lower alpha and beta power and spectral edge frequency on injured compared with uninjured regions. This was not consistent after hemorrhagic stroke ( n = 6). All hemorrhagic stroke patients demonstrated negative association of total power with arterial blood pressure within injured regions. No consistency was observed for direction or strength of association in other QEEG measures to arterial blood pressure nor were such consistent relationships observed for any QEEG measure studied in relation to heart rate or cerebral oximetry. After pediatric anterior circulation acute ischemic stroke, reduced spectral edge frequency and alpha and beta power can be observed on injured as compared with noninjured regions. After pediatric anterior circulation hemorrhagic stroke, total power can be negatively associated with arterial blood pressure within injured regions. Larger studies are needed to understand conditions in which QEEG patterns manifest and relate to hemodynamics and brain penumbra.

Prevalence of spatial neglect post-stroke: A systematic review.

Spatial neglect (SN) impedes stroke rehabilitation progress, slows functional recovery, and increases caregiver stress and burden. The estimation of SN prevalence varies widely across studies. We aimed to establish the prevalence of SN based on the injured cerebral hemisphere, recovery stage post-stroke, and diagnostic methodology. All journal articles published up to February 27, 2019 from CINAHL, PsycINFO, PubMed and Web of Science were searched. We selected original research articles that described observational studies, included both individuals with left brain damage (LBD) and those with right brain damage (RBD) post-stroke, and reported specific diagnostic methods for SN. All authors reached consensus for the final selection of 41 articles. Time post-stroke, patient selection criteria, study setting, SN diagnostic methods were extracted. A total of 6324 participants were included: 3411 (54%) with RBD and 2913 (46%) with LBD. Without considering time post-stroke or diagnostic methods, the occurrence rate of SN was 29% (38% after RBD and 18% after LBD). Using ecological assessments resulted in higher prevalence than using tests not directly related to daily life activities (53% vs. 24%). Using methods based on a single-cutoff criterion led to lower occurrence of SN than using multi-test methods (27% vs. 33%). The prevalence decreased from the acute to chronic stage post-stroke. The estimated prevalence of SN after unilateral stroke is 30%. SN is more common after RBD than after LBD, but SN after LBD is still quite common. Using ecological assessments and multi-test methods to detect SN is preferred to using a single-cutoff criterion of a test that is not directly related to daily function. The decrease in SN prevalence over time is evident, but the exact prevalence in later stages cannot be estimated. More research is needed to better understand chronic SN.

A scalable, fully automated approach for regional quantification of immunohistochemical staining of astrocytes in the rat brain

BackgroundAstrocytes play a critical role in CNS functions by providing physiological support to surrounding cells. These cells present a particularly unique challenge for in vitro immunohistochemical quantification due reactive gliosis after insult or injury, which is characterized by the extension of long processes. New methodWe present an optimized QuPath protocol that is scalable, fully automated, and capable of being applied to images generated by whole slide scanning technology using this open-source software. ResultsWe induced mechanical injury in the rat brain and stained astrocytes using glial fibrillary acidic protein (GFAP) and 3,3-diaminobenzidine (DAB) chromogen detection. Slides were scanned using a whole slide scanner, Vectra Polaris. Using QuPath, we summarize and contrast three ways of quantifying astrocytes in uninjured (contralateral) and injured (ipsilateral) hemispheres: optical density, positive pixels and positive proportion. Comparison with existing methodsRobust quantification of DAB stained astrocytes remains elusive. Previous methodologies have relied on software that is not compatible with whole slide scanner images. Use of such software can compromise the data integrity within the image and is limited by issues with scalability and lack of automation. Previous methods using manual histopathological scoring are also limited by the ability to quantify large numbers of astrocytes. Given these limitations, we were unable to directly compare our method with those using other software or manual histopathology. ConclusionsBased on an analysis of our method, we conclude that positive proportion may be the most effective way to quantify astrocytic responses using GFAP and DAB immunohistochemistry in the brain.

Poly(ester amide) microspheres are efficient vehicles for long-term intracerebral growth factor delivery and improve functional recovery after stroke

Growth factors promote plasticity in injured brain and improve impaired functions. For clinical application, efficient approaches for growth factor delivery into the brain are necessary. Poly(ester amide) (PEA)-derived microspheres (MS) could serve as vehicles due to their thermal and mechanical properties, biocompatibility and biodegradability. Vascular endothelial growth factor (VEGF) exerts both vascular and neuronal actions, making it suitable to stimulate post-stroke recovery. Here, PEA (composed of adipic acid, L-phenyl-alanine and 1,4-butanediol) MS were loaded with VEGF and injected intracerebrally in mice subjected to cortical stroke. Loaded MS provided sustained release of VEGF in vitro and, after injection, biologically active VEGF was released long-term, as evidenced by high VEGF immunoreactivity, increased VEGF tissue levels, and higher vessel density and more NG2+ cells in injured hemisphere of animals with VEGF-loaded as compared to non-loaded MS. Loaded MS gave rise to more rapid recovery of neurological score. Both loaded and non-loaded MS induced improvement in neurological score and adhesive removal test, probably due to anti-inflammatory action. In summary, grafted PEA MS can act as efficient vehicles, with anti-inflammatory action, for long-term delivery of growth factors into injured brain. Our data suggest PEA MS as a new tool for neurorestorative approaches with therapeutic potential.

Type 2 Innate Lymphoid Cells Accumulate in the Brain After Hypoxia-Ischemia but Do Not Contribute to the Development of Preterm Brain Injury.

BackgroundThe immune system of human and mouse neonates is relatively immature. However, innate lymphoid cells (ILCs), commonly divided into the subsets ILC1, ILC2, and ILC3, are already present in the placenta and other fetal compartments and exhibit higher activity than what is seen in adulthood. Recent reports have suggested the potential role of ILCs, especially ILC2s, in spontaneous preterm labor, which is associated with brain damage and subsequent long-term neurodevelopmental deficits. Therefore, we hypothesized that ILCs, and especially ILC2s, play a role in preterm brain injury.MethodsC57Bl/6J mice at postnatal day 6 were subjected to hypoxia-ischemia (HI) insult induced by left carotid artery ligation and subsequent exposure to 10% oxygen in nitrogen. The presence of ILCs and ILC2s in the brain was examined at different time points after HI. The contribution of ILC2s to HI-induced preterm brain damage was explored using a conditionally targeted ILC2-deficient mouse strain (Rorαfl/flIL7rCre), and gray and white-matter injury were evaluated at 7 days post-HI. The inflammatory response in the injured brain was assessed using immunoassays and immunochemistry staining.ResultsSignificant increases in ILCs and ILC2s were observed at 24 h, 3 days, and 7 days post-HI in the injured brain hemisphere compared with the uninjured hemisphere in wild-type mice. ILC2s in the brain were predominantly located in the meninges of the injured ipsilateral hemispheres after HI but not in the brain parenchyma. Overall, we did not observe changes in cytokine/chemokine levels in the brains of Rorαfl/flIL7rCre mice compared with wild type animals apart from IL-13. Gray and white-matter tissue loss in the brain was not affected after HI in Rorαfl/flIL7rCre mice. Correspondingly, we did not find any differences in reactive microglia and astrocyte numbers in the brain in Rorαfl/flIL7rCre mice compared with wild-type mice following HI insult.ConclusionAfter HI, ILCs and ILC2s accumulate in the injured brain hemisphere. However, ILC2s do not contribute to the development of brain damage in this mouse model of preterm brain injury.

Densitometric analysis of brain computed tomography as a new prognostic factor in patients with acute subdural hematoma.

Acute subdural hematoma (ASDH) is a major cause of mortality and morbidity after traumatic brain injury (TBI). Surgical evacuation is the mainstay of treatment in patients with altered neurological status or significant mass effect. Nevertheless, concerns regarding surgical indication still persist. Given that clinicians often make therapeutic decisions on the basis of their prognosis assessment, to accurately evaluate the prognosis is of great significance. Unfortunately, there is a lack of specific and reliable prognostic models. In addition, the interdependence of certain well-known predictive variables usually employed to guide surgical decision-making in ASDH has been proven. Because gray matter and white matter are highly susceptible to secondary insults during the early phase after TBI, the authors aimed to assess the extent of these secondary insults with a brain parenchyma densitometric quantitative CT analysis and to evaluate its prognostic capacity. The authors performed a retrospective analysis among their prospectively collected cohort of patients with moderate to severe TBI. Patients with surgically evacuated, isolated, unilateral ASDH admitted between 2010 and 2017 were selected. Thirty-nine patients were included. For each patient, brain parenchyma density in Hounsfield units (HUs) was measured in 10 selected slices from the supratentorial region. In each slice, different regions of interest (ROIs), including and excluding the cortical parenchyma, were defined. The injured hemisphere, the contralateral hemisphere, and the absolute differences between them were analyzed. The outcome was evaluated using the Glasgow Outcome Scale-Extended at 1 year after TBI. Fifteen patients (38.5%) had a favorable outcome. Collected demographic, clinical, and radiographic data did not show significant differences between favorable and unfavorable outcomes. In contrast, the densitometric analysis demonstrated that greater absolute differences between both hemispheres were associated with poor outcome. These differences were detected along the supratentorial region, but were greater at the high convexity level. Moreover, these HU differences were far more marked at the cortical parenchyma. It was also detected that these differences were more prone to ischemic and/or edematous insults than to hyperemic changes. Age was significantly correlated with the side-to-side HU differences in patients with unfavorable outcome. The densitometric analysis is a promising prognostic tool in patients diagnosed with ASDH. The supplementary prognostic information provided by the densitometric analysis should be evaluated in future studies.

High frequency electrical field-ultrashort wave therapy for treatment of cerebral ischemia/reperfusion injury in rats*: Histopathological evaluation

Abstract BACKGROUND Ultrashortwave (USW) therapy may be a new method for treatment of ischemic cerebrovascular diseases. It is necessary to study its treatment time window. OBJECTIVE To observe the effect of USW on reperfusion injury after occlusion of the middle cerebral artery (MCAO) in rats and discuss its acting mechanisms and best occasion. DESIGN Randomized controlled observation, animal experiment. SETTING Laboratory of Department of Rehabilitation Medicine, First Hospital Affiliated to China Medical University. MATERIALS Sixty-six healthy Wistar rats of either gender and of clean grade, aged 18 – 20 weeks, weighing from 250 to 300 g, were provided by the Experimental Animal Center of China Medical University. An USW device (Shanghai Electrical Device Company) with the frequency of 40.68 MHz and the maximum output power of 40 W, and the first channel power controlled at about 11 W was used in this study. Output power was determined by photometry. METHODS Sixty-six rats were randomly divided into 3 groups: Sham-operation group (n = 6): The suture was inserted only 1.0 depth during operation, which did not cause MACO; Model group (n = 12): The USW treatment procedure was performed with the power off on the model rats; USW treatment group (n = 48): The 48 rats were randomly divided into modeling 0, 6, 12 and 18 hours 4 subgroups. USW therapy without heat was used on the head of rats for 10 minutes at each time point. Twelve rats in USW treatment group were decapitated following treatment at each time point, and then their brain tissues were harvested. The rat brain tissues in other groups were harvested by decapitation at 24 hours after modeling. When the rats were awake, the neurologic deficit was scored by Zea-Longa five-point scale (a score of 0 indicated no neurologic deficit, a score of 1 indicated failure to extend left paw fully, a score of 2 indicated circling to the left, and a score of 3 indicated falling to the left, and rats with a score of 4 did not walk spontaneously and has a depressed level of consciousness.) Rats which still survived at 24 hours and was scored 1 and 2 on the neurologic scoring were involved in the analysis. (1) Determination of cerebral water content: Cerebral water contents of healthy and injured hemisphere were determined by wet/dry weighing method. Cerebral water content (100%) = (1 – dry/wet weight) × 100%. (2)Infarction volume: The brain tissue was sliced into 2 mm sections and each section was stained with 20 g/L 2,3,5-triphenyltetrazolium chloride (TTC) by TTC staining technique for 30 minutes in a water bath at 37 °C. Then, the section was fixed in 100 g/L formaldehyde for 10 minutes. The infarction volume was analyzed by using an imaging analyzer. (3) Preparation of light microscopic sample: The rat brain tissue fixed by 100 g/L neutral formaldehyde and stained with TTC, were gradiently dehydrated with alcoholic, embedded with paraffin, sliced and stained by HE, finally, the sections were observed under the light microscope. MAIN OUTCOME MEASURES Cerebral water content, cerebral infarction volume and cerebral histomorphology of rats in each group. RESULTS Sixty-six rats were involved in the final analysis. (1) Cerebral water content: There were no significant differences of cerebral water content in healthy hemisphere among groups (P > 0.05). Cerebral water content of injured hemisphere in the model group and at modeling 0, 6, 12 and 18 hours in the USW treatment group was (81.50±0.74) %, (81.02±0.83) %, (79.78±0.70) %, (79.74±0.84) %, (79.39±1.06) %, respectively, which was significantly higher than that in the sham-operation group [(78.09±0.52) %, P CONCLUSION USW may play a protective effect on cerebral ischemia/reperfusion injury by decreasing brain edema and/or cerebral infarction volume. The treatment action of USW may start at 6 hours after reperfusion, and the best occasion of application may be at 18 hours after reperfusion.

Fe Porphyrin-Based SOD Mimic and Redox-Active Compound, (OH)FeTnHex-2-PyP4+, in a Rodent Ischemic Stroke (MCAO) Model: Efficacy and Pharmacokinetics as Compared to Its Mn Analogue, (H2O)MnTnHex-2-PyP5+.

Mn(III) meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin, (H2O)MnTnHex-2-PyP5+ (MnHex) carrying long hexyl chains, is a lipophilic mimic of superoxide dismutase (SOD) and a redox-active drug candidate. MnHex crosses the blood–brain barrier, and improved neurologic outcome and decreased infarct size and inflammation in a rat middle cerebral artery occlusion (MCAO) ischemic stroke model. Yet, the dose and the therapeutic efficacy of Mn porphyrin were limited by an adverse effect of arterial hypotension. An equally lipophilic Fe analog, (OH)FeTnHex-2-PyP4+ (FeHex), is as redox-active and potent SOD mimic in vitro. With different coordination geometry of the metal site, FeHex has one hydroxo (OH) ligand (instead of water) bound to the Fe center in the axial position. It has ~2 orders of magnitude higher efficacy than MnHex in an SOD-deficient E. coli model of oxidative stress. In vivo, it does not cause arterial hypotension and is less toxic to mice. We thus evaluated FeHex versus MnHex in a rodent MCAO model. We first performed short- and long-term pharmacokinetics (PK) of both porphyrins in the plasma, brain, and liver of rats and mice. Given that damage to the brain during stroke occurs very rapidly, fast delivery of a sufficient dose of drug is important. Therefore, we aimed to demonstrate if, and how fast after reperfusion, Fe porphyrin reaches the brain relative to the Mn analog. A markedly different plasma half-life was found with FeHex (~23 h) than with MnHex (~1.4 h), which resulted in a more than 2-fold higher plasma exposure (AUC) in a 7-day twice-daily treatment of rats. The increased plasma half-life is explained by the much lower liver retention of FeHex than typically found in Mn analogs. In the brain, a 3-day mouse PK study showed similar levels of MnHex and FeHex. The same result was obtained in a 7-day rat PK study, despite the higher plasma exposure of FeHex. Importantly, in a short-term PK study with treatment starting 2 h post MCAO, both Fe- and Mn- analogs distributed at a higher level to the injured brain hemisphere, with a more pronounced effect observed with FeHex. While a 3-day mouse MCAO study suggested the efficacy of Fe porphyrin, in a 7-day rat MCAO study, Mn-, but not Fe porphyrin, was efficacious. The observed lack of FeHex efficacy was discussed in terms of significant differences in the chemistry of Fe vs. the Mn center of metalloporphyrin; relative to MnHex, FeHex has the propensity for axial coordination, which in vivo would preclude the reactivity of the Fe center towards small reactive species.

Sex differences in the therapeutic effects of anti-PDL2 neutralizing antibody on stroke.

Inflammation involving migration of immune cells across the damaged blood-brain barrier (BBB), activation of resident innate microglia and production of inflammatory humoral mediators such as cytokines and chemokines play a critical role in the pathogenesis of ischemic stroke. Cell-cell signaling involved in the process also includes checkpoint interaction between programmed death receptor (PD1) and programmed death ligands, PDL1 and PDL2. Based on our previous studies showing reduced MCAO infarct volumes in PDL2 deficient mice, we evaluated the ability of anti-PDL2 mAb to treat MCAO in male and female C57BL/6 mice. We found that anti-PDL2 neutralizing antibody treatment of MCAO significantly reduced infarct volumes in male mice but had no protective effects in female mice even at a 5-fold increased dose of anti-PDL2 mAb. The protection in male mice was likely mediated by reduced percentages in the spleen of PDL2+CD19+ B cells, PDL1+CD4+ T cells and CD86+CD11b+ macrophages in concert with reduced expression of PDL1 and TNFα and continued expression of CD206, in the injured ipsilateral brain hemisphere. The lack of a therapeutic benefit of anti-PDL2 on stroke-induced infarct volumes in female mice was reflected by no detectable reduction in expressed PDL2 or PDL1 and an increased frequency of Th1 and Th17 pro-inflammatory T cell subsets in the spleen, an effect not seen in PDL2 mAb treated males. This result potentially limits the utility of anti-PDL2 mAb therapy in stroke to males but underscores the importance of meeting the STAIR requirements for development of new stroke therapies for both sexes.

Deficit of Motor Skill Acquisition on the Upper Limb Ipsilesional to the Injured Hemisphere in Individuals with Stroke.

BackgroundMovement deficits in limbs ipsilesional to the damaged hemisphere in individuals with stroke have been established through various motor tasks. Nevertheless, there has been little evidence regarding hindrance of motor skill acquisition on the ipsilesional limb in patients with stroke. Therefore, we attempted to demonstrate whether the characteristics of ipsilesional deficits involved motor learning insufficiency in stroke survivors with unilateral brain damage.Material/MethodsThirty-six participants (18 patients with stroke and 18 normal individuals) were recruited. Patients with stroke performed a visuo-spatial tracking task in the upper limb ipsilesional to the injured hemisphere, and normal participants did the same task with the upper limb matched for the same side. The participants were required to track a target sine wave as accurately as possible while the wave was displayed on the computer screen for 15 seconds. An accuracy index was calculated for each of the trials.ResultsWe found that motor skill learning improved in both stroke and normal groups with repetitive practice. However, the normal group exhibited greater motor skill acquisition than in comparison the stroke group for motor skill improvement. Statistical analyses revealed significant differences in time effects and time x group interactions.ConclusionsOur findings provide evidence that individuals with stroke might have difficulty in performing visuo-spatial movements and acquiring motor skills with the ipsilateral upper limb. Improvement of ipsilesional limb function increases self-care activity in daily life. Therefore, we recommend that clinicians adopt remedial strategies for ipsilesional limbs.