Bi-directional neuro-immune dysfunction after chronic experimental brain injury.

BACKGROUND: It is well established that traumatic brain injury (TBI) causes acute and chronic alterations in systemic immune function and that systemic immune changes contribute to posttraumatic neuroinflammation and neurodegeneration. However, how TBI affects bone marrow (BM) hematopoietic stem/progenitor cells chronically and to what extent such changes may negatively impact innate immunity and neurological function has not been examined. METHODS: To further understand the role of BM cell derivatives on TBI outcome, we generated BM chimeric mice by transplanting BM from chronically injured or sham (i.e., 90 days post-surgery) congenic donor mice into otherwise healthy, age-matched, irradiated CD45.2 C57BL/6 (WT) hosts. Immune changes were evaluated by flow cytometry, multiplex ELISA, and NanoString technology. Moderate-to-severe TBI was induced by controlled cortical impact injury and neurological function was measured using a battery of behavioral tests. RESULTS: TBI induced chronic alterations in the transcriptome of BM lineage-c-Kit+Sca1+ (LSK+) cells in C57BL/6 mice, including modified epigenetic and senescence pathways. After 8 weeks of reconstitution, peripheral myeloid cells from TBI→WT mice showed significantly higher oxidative stress levels and reduced phagocytic activity. At eight months after reconstitution, TBI→WT chimeric mice were leukopenic, with continued alterations in phagocytosis and oxidative stress responses, as well as persistent neurological deficits. Gene expression analysis revealed BM-driven changes in neuroinflammation and neuropathology after 8 weeks and 8 months of reconstitution, respectively. Chimeric mice subjected to TBI at 8 weeks and 8 months post-reconstitution showed that longer reconstitution periods (i.e., time post-injury) were associated with increased microgliosis and leukocyte infiltration. Pre-treatment with a senolytic agent, ABT-263, significantly improved behavioral performance of aged C57BL/6 mice at baseline, although it did not attenuate neuroinflammation in the acutely injured brain. CONCLUSIONS: TBI causes chronic activation and progressive dysfunction of the BM stem/progenitor cell pool, which drives long-term deficits in hematopoiesis, innate immunity, and neurological function, as well as altered sensitivity to subsequent brain injury.

Luteolin-7-O-ß-d-glucuronide Ameliorates Cerebral Ischemic Injury: Involvement of RIP3/MLKL Signaling Pathway.

Luteolin-7-O-ß-d-glucuronide (LGU) is a major active flavonoid glycoside compound that is extracted from Ixeris sonchifolia (Bge.) Hance, and it is a Chinese medicinal herb mainly used for the treatment of coronary heart disease, angina pectoris, cerebral infarction, etc. In the present study, the neuroprotective effect of LGU was investigated in an oxygen glucose deprivation (OGD) model and a middle cerebral artery occlusion (MCAO) rat model. In vitro, LGU was found to effectively improve the OGD-induced decrease in neuronal viability and increase in neuronal death by a 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and a lactate dehydrogenase (LDH) leakage rate assay, respectively. LGU was also found to inhibit OGD-induced intracellular Ca2+ overload, adenosine triphosphate (ATP) depletion, and mitochondrial membrane potential (MMP) decrease. By Western blotting analysis, LGU significantly inhibited the OGD-induced increase in expressions of receptor-interacting serine/threonine-protein kinase 3 (RIP3) and mixed lineage kinase domain-like protein (MLKL). Moreover, molecular docking analysis showed that LGU might bind to RIP3 more stably and firmly than the RIP3 inhibitor GSK872. Immunofluorescence combined with confocal laser analyses disclosed that LGU inhibited the aggregation of MLKL to the nucleus. Our results suggest that LGU ameliorates OGD-induced rat primary cortical neuronal injury via the regulation of the RIP3/MLKL signaling pathway in vitro. In vivo, LGU was proven, for the first time, to protect the cerebral ischemia in a rat middle cerebral artery occlusion (MCAO) model, as shown by improved neurological deficit scores, infarction volume rate, and brain water content rate. The present study provides new insights into the therapeutic potential of LGU in cerebral ischemia.

Brain magnetic resonance imaging review suggests unrecognised hypoglycaemia in childhood.

Introduction: Neonatal and early-life hypoglycaemia, is a frequent finding but is often non-specific and asymptomatic, making detection and diagnosis challenging. Hypoglycaemia-induced cerebral injury can be identified by magnetic resonance imaging (MRI) changes in cerebral white matter, occipital lobes, and posterior parietotemporal regions. It is unknown if children may have hypoglycaemic brain injury secondary to unrecognised hypoglycaemia in early life. We have examined retrospective radiological findings of likely brain injury by neuroimaging to investigate the existence of previous missed hypoglycaemic events. Methods: Retrospective MRI data in children in a single tertiary centre, over a ten-year period was reviewed to identify potential cases of unrecognised early-life hypoglycaemia. A detailed search from an electronic radiology repository involved the term "hypoglycaemia'' from text-based reports. The initial report was used for those who required serial scanning. Images specific to relevant reports were further reviewed by a designated paediatric neuroradiologist to confirm likely hypoglycaemia induced brain injury. Medical records of those children were subsequently reviewed to assess if the hypoglycaemia had been diagnosed prior to imaging. Results: A total of 107 MR imaging reports were identified for review, and 52 (48.5%) showed typical features strongly suggestive of hypoglycaemic brain injury. Medical note review confirmed no documented clinical information of hypoglycaemia prior to imaging in 22 (42%) patients, raising the likelihood of missed hypoglycaemic events resulting in brain injury. Conclusions: We have identified the existence of unrecognised childhood hypoglycaemia through neuroimaging review. This study highlights the need for heightened awareness of early life hypoglycaemia to prevent adverse neurological outcomes later in childhood.

Visual evoked potential evaluation following brain injury in school-aged children.

Aim: The research aimed to establish reference values of visual evoked potentials among school-aged children after brain injury. Methods: Eighteen patients with persisting visual symptoms after brain injury have been examined. A pattern-VEP test has been used during the examination. Results: The prolongation of the N2 wave in 55,6%-66,6%, P wave in 55,7%-66,7%, and N3 wave in 16,7%-22,2% was determined in the research group. Likewise, the decrease in the amplitude of the P wave was determined in the case of 16,7%-33,3%. According to the topography, we concluded that the prechiasmatic alteration was predominantly determined as bilateral in the optic pathways, with emphasis equally on the right and left. Conclusions: VEP evaluation remains one of the most credible methods of examination. In the case of moderate or severe traumatic optic neuropathy, it allows the detection of damage to the optic pathways before the appearance of organic changes that are often irreversible. The possibility of early detection of such modifications could justify the initiation of a dosed stimulatory treatment, to avoid damage to the optic pathways that would induce secondary optic atrophy. Abbreviations: VEP = visual evoked potentials, MRI = magnetic resonance imaging.

Hyperoxia and brain: the link between necessity and injury from a molecular perspective.

Oxygen (O2) supplementation is commonly used to treat hypoxia in patients with respiratory failure. However, indiscriminate use can lead to hyperoxia, a condition detrimental to living tissues, particularly the brain. The brain is sensitive to reactive oxygen species (ROS) and inflammation caused by high concentrations of O2, which can result in brain damage and mitochondrial dysfunction, common features of neurodegenerative disorders. Hyperoxia leads to increased production of ROS, causing oxidative stress, an imbalance between oxidants and antioxidants, which can damage tissues. The brain is particularly vulnerable to oxidative stress due to its lipid composition, high O2 consumption rate, and low levels of antioxidant enzymes. Moreover, hyperoxia can cause vasoconstriction and decreased O2 supply to the brain, posing a challenge to redox balance and neurodegenerative processes. Studies have shown that the severity of hyperoxia-induced brain damage varies with inspired O2 concentration and duration of exposure. Therefore, careful evaluation of the balance between benefits and risks of O2 supplementation, especially in clinical settings, is crucial.

Functional brain networks in Developmental Topographical Disorientation.

Despite a decade-long study on Developmental Topographical Disorientation, the underlying mechanism behind this neurological condition remains unknown. This lifelong selective inability in orientation, which causes these individuals to get lost even in familiar surroundings, is present in the absence of any other neurological disorder or acquired brain damage. Herein, we report an analysis of the functional brain network of individuals with Developmental Topographical Disorientation ($n = 19$) compared against that of healthy controls ($n = 21$), all of whom underwent resting-state functional magnetic resonance imaging, to identify if and how their underlying functional brain network is altered. While the established resting-state networks (RSNs) are confirmed in both groups, there is, on average, a greater connectivity and connectivity strength, in addition to increased global and local efficiency in the overall functional network of the Developmental Topographical Disorientation group. In particular, there is an enhanced connectivity between some RSNs facilitated through indirect functional paths. We identify a handful of nodes that encode part of these differences. Overall, our findings provide strong evidence that the brain networks of individuals suffering from Developmental Topographical Disorientation are modified by compensatory mechanisms, which might open the door for new diagnostic tools.

Mitochondrial Calcium Uniporter (MCU) is Involved in an Ischemic Postconditioning Effect Against Ischemic Reperfusion Brain Injury in Mice.

The phenomenon of ischemic postconditioning (PostC) is known to be neuroprotective against ischemic reperfusion (I/R) injury. One of the key processes in PostC is the opening of the mitochondrial ATP-dependent potassium (mito-KATP) channel and depolarization of the mitochondrial membrane, triggering the release of calcium ions from mitochondria through low-conductance opening of the mitochondrial permeability transition pore. Mitochondrial calcium uniporter (MCU) is known as a highly sensitive transporter for the uptake of Ca2+ present on the inner mitochondrial membrane. The MCU has attracted attention as a new target for treatment in diseases, such as neurodegenerative diseases, cancer, and ischemic stroke. We considered that the MCU may be involved in PostC and trigger its mechanisms. This research used the whole-cell patch-clamp technique on hippocampal CA1 pyramidal cells from C57BL mice and measured changes in spontaneous excitatory post-synaptic currents (sEPSCs), intracellular Ca2+ concentration, mitochondrial membrane potential, and N-methyl-D-aspartate receptor (NMDAR) currents under inhibition of MCU by ruthenium red 265 (Ru265) in PostC. Inhibition of MCU increased the occurrence of sEPSCs (p = 0.014), NMDAR currents (p < 0.001), intracellular Ca2+ concentration (p < 0.001), and dead cells (p < 0.001) significantly after reperfusion, reflecting removal of the neuroprotective effects in PostC. Moreover, mitochondrial depolarization in PostC with Ru265 was weakened, compared to PostC (p = 0.004). These results suggest that MCU affects mitochondrial depolarization in PostC to suppress NMDAR over-activation and prevent elevation of intracellular Ca2+ concentrations against I/R injury.

Shared inflammatory glial cell signature after stab wound injury, revealed by spatial, temporal, and cell-type-specific profiling of the murine cerebral cortex.

Traumatic brain injury leads to a highly orchestrated immune- and glial cell response partially responsible for long-lasting disability and the development of secondary neurodegenerative diseases. A holistic understanding of the mechanisms controlling the responses of specific cell types and their crosstalk is required to develop an efficient strategy for better regeneration. Here, we combine spatial and single-cell transcriptomics to chart the transcriptomic signature of the injured male murine cerebral cortex, and identify specific states of different glial cells contributing to this signature. Interestingly, distinct glial cells share a large fraction of injury-regulated genes, including inflammatory programs downstream of the innate immune-associated pathways Cxcr3 and Tlr1/2. Systemic manipulation of these pathways decreases the reactivity state of glial cells associated with poor regeneration. The functional relevance of the discovered shared signature of glial cells highlights the importance of our resource enabling comprehensive analysis of early events after brain injury.

Repetitive transcranial magnetic stimulation ameliorates cognitive deficits in mice with radiation-induced brain injury by attenuating microglial pyroptosis and promoting neurogenesis via BDNF pathway.

BACKGROUND: Radiation-induced brain injury (RIBI) is a common and severe complication during radiotherapy for head and neck tumor. Repetitive transcranial magnetic stimulation (rTMS) is a novel and non-invasive method of brain stimulation, which has been applied in various neurological diseases. rTMS has been proved to be effective for treatment of RIBI, while its mechanisms have not been well understood. METHODS: RIBI mouse model was established by cranial irradiation, K252a was daily injected intraperitoneally to block BDNF pathway. Immunofluorescence staining, immunohistochemistry and western blotting were performed to examine the microglial pyroptosis and hippocampal neurogenesis. Behavioral tests were used to assess the cognitive function and emotionality of mice. Golgi staining was applied to observe the structure of dendritic spine in hippocampus. RESULTS: rTMS significantly promoted hippocampal neurogenesis and mitigated neuroinflammation, with ameliorating pyroptosis in microglia, as well as downregulation of the protein expression level of NLRP3 inflammasome and key pyroptosis factor Gasdermin D (GSDMD). BDNF signaling pathway might be involved in it. After blocking BDNF pathway by K252a, a specific BDNF pathway inhibitor, the neuroprotective effect of rTMS was markedly reversed. Evaluated by behavioral tests, the cognitive dysfunction and anxiety-like behavior were found aggravated with the comparison of mice in rTMS intervention group. Moreover, the level of hippocampal neurogenesis was found to be attenuated, the pyroptosis of microglia as well as the levels of GSDMD, NLRP3 inflammasome and IL-1ß were upregulated. CONCLUSION: Our study indicated that rTMS notably ameliorated RIBI-induced cognitive disorders, by mitigating pyroptosis in microglia and promoting hippocampal neurogenesis via mediating BDNF pathway.

Gathering Self-Initiated Rat Behavioral Data to Characterize Post-Stroke Deficits.

Behavioral testing in rat models is frequently utilized for diverse purposes, including psychological, biomedical, and behavioral research. Many traditional approaches involve individual, one-on-one testing sessions between a single researcher and each animal in an experiment. This setup can be very time consuming for the researcher, and their presence may impact the behavioral data in unwanted ways. Additionally, traditional caging for rat research imposes a lack of enrichment, exercise, and socialization that would normally be typical for the species, and this context may also skew the results of behavioral data. Overcoming these limitations may be worthwhile for several research applications, including the study of acquired brain injury. Here, an example method is presented for automatically training and testing individual rat behavior in a colony cage without the presence of humans. Radio frequency identification can be utilized to tailor sessions to the individual rat. The validation of this system occurred in the example context of measuring skilled forelimb motor performance before and after stroke. Traditional characteristics of post-stroke behavioral impairments and novel measures enabled by the system are measured, including success rate, various aspects of pull force, bout analysis, initiation rate and patterns, session duration, and circadian patterns. These variables can be collected automatically with few limitations; though the apparatus removes experimental control of exposure, timing and practice, the validation produced reasonable consistency in these variables from animal to animal.

[Injury mechanism, clinical status and prospects of traumatic brain injury].

Traumatic brain injury (TBI) is an important in the world's public health and an important subject of basic and clinical research in the medical field. In the past 30 years, the epidemiology, injury mechanism, safety prevention, medical strategies, nursing measures and other aspects of TBI have made great progress, and the level of treatment has also been continuously improved, but it still faces many challenges. The focus of research on the injury mechanism of TBI has gradually shifted from the classic signaling pathways of primary injury to the study of secondary injury mechanisms. Pharmacological research on various therapeutic targets has also made significant progress, which is expected to be transformed into new TBI therapeutic drugs. On the other hand, many new clinical concepts, new systems, and new methods are constantly being integrated into the diagnosis and treatment of TBI, which has gradually transformed from the original treatment of acute neurological injury to the comprehensive treatment of chronic systemic diseases. This paper is based on the latest research progress in the basic and clinical aspects of TBI, and provides a review of its current status and development trends, providing reference for the medical treatment and research of TBI.

Treatment with RNase alleviates brain injury but not neuroinflammation in neonatal hypoxia/ischemia.

There is a need for new treatments to reduce brain injuries derived from neonatal hypoxia/ischemia. The only viable option used in the clinic today in infants born at term is therapeutic hypothermia, which has a limited efficacy. Treatments with exogenous RNase have shown great promise in a range of different adult animal models including stroke, ischemia/reperfusion injury, or experimental heart transplantation, often by conferring vascular protective and anti-inflammatory effects. However, any neuroprotective function of RNase treatment in the neonate remains unknown. Using a well-established model of neonatal hypoxic/ischemic brain injury, we evaluated the influence of RNase treatment on RNase activity, gray and white matter tissue loss, blood-brain barrier function, as well as levels and expression of inflammatory cytokines in the brain up to 6 h after the injury using multiplex immunoassay and RT-PCR. Intraperitoneal treatment with RNase increased RNase activity in both plasma and cerebropinal fluids. The RNase treatment resulted in a reduction of brain tissue loss but did not affect the blood-brain barrier function and had only a minor modulatory effect on the inflammatory response. It is concluded that RNase treatment may be promising as a neuroprotective regimen, whereas the mechanistic effects of this treatment appear to be different in the neonate compared to the adult and need further investigation.

ADAMTS13 deficiency exacerbates neuroinflammation by targeting matrix metalloproteinase-9 in ischemic brain injury.

Our design aimed to explore the potential involvement of matrix metalloproteinase-9 (MMP-9) in the inflammatory response associated with acute ischemic stroke (AIS). We also aimed to preliminarily examine the potential impact of a disintegrin-like and metalloprotease with thrombospondin type I repeats-13 (ADAMTS13) on MMP-9 in AIS. We conducted oxygen-glucose deprivation models of microglia cells and mice models of AIS with middle cerebral artery occlusion (MCAO). We assessed the expression pattern of MMP-9 with western blotting (WB) and real-time quantitative PCR both in vivo and in vitro. MMP-9 downregulation was achieved by using ACE inhibitors such as trandolapril. For the MCAO model, we used ADAMTS13-deficient mice. We then evaluated the related neurological function scores, cerebral edema and infarct volume. The levels of inflammation-related proteins, such as COX2 and iNOS, were assessed using WB, and the expression of inflammatory cytokines was measured via enzyme-linked immuno sorbent assay in vivo. Our findings indicated that MMP-9 was up-regulated while ADAMTS13 was down-regulated in the MCAO model. Knockdown of MMP-9 reduced both inflammation and ischemic brain injury. ADAMTS13 prevented brain damage, improved neurological function and decreased the inflammation response in mice AIS models. Additionally, ADAMTS13 alleviated MMP-9-induced neuroinflammation in vivo. It showed that ADAMTS13 deficiency exacerbated ischemic brain injury through an MMP-9-dependent inflammatory mechanism. Therefore, the ADAMTS13-MMP-9 axis could have therapeutic potential for the treatment of AIS.

The results of the corrective rehabilitation program on the gait of amateur athletes with long-term consequences of brain injury.

OBJECTIVE: Aim: To study the results of the quality of life, the state of vestibular disorders and the nature of walking of amateur athletes with the consequences of a combat craniocerebral injury after rehabilitation treatment according to a correctional program. PATIENTS AND METHODS: Materials and Methods: The study was conducted on the basis of the Ukrainian Scientific Research Institute of Prosthetics in Kharkov. Under observation were 38 men aged 25-42 years with long-term consequences of a closed craniocerebral injury in the late long-term period. In all patients, complications after TBI were persistent headache, decreased muscle strength in the lower extremities, impaired coordination and balance, and walking patterns. All patients were involved in amateur sports before injury. The following research methods were used during the examination: visual analogue pain scale (VAS), Lovett manual muscle test, Bohannon test, ≪Timed Up and Go test≫. RESULTS: Results: All patients were randomly divided into two groups. Patients Gr.1 (n=20) were trained according to the developed program, which included training according to the PNF method, kinesiotherapy, classes on the C-mill sensory treadmill and the Hunova computer device, segmental reflex massage. Patients Gr. 2 (n=18) underwent a course of physical rehabilitation according to the generally accepted methodology of the Ministry of Health of Ukraine. After working with patients according to the developed correction and rehabilitation program, the following dynamics were observed: the quality of life on the VAS scale in Gr.1 patients had a statistically significant difference (p<0.05) compared to the primary indicator. The dynamics of the Lovett manual muscle test indicated an increase in the muscle strength of the extensor and flexor muscle groups of the lower extremities, the dynamics of the balance indicator in the standing position behind Bohann in all Gr.1 patients and acquired statistical significance (p<0,05). According to the test "Timed Up and Go" patients Gr.1 approached the standard value (p<0,05). In all patients of Gr. 2, the studied characteristics had a positive trend (p>0,05). CONCLUSION: Conclusions: Individual selection of physical exercises, development of correctional and rehabilitation programs, multidisciplinary approach has a positive impact on changes in the functional state of amateur athletes, quality of life and contributes to the return to an active social life.

Understanding factors that influence goal setting in rehabilitation for paediatric acquired brain injury: a qualitative study using the Theoretical Domains Framework.

Background While goal setting with children and their families is considered best practice during rehabilitation following acquired brain injury, its successful implementation in an interdisciplinary team is not straightforward. This paper describes the application of a theoretical framework to understand factors influencing goal setting with children and their families in a large interdisciplinary rehabilitation team. Methods A semi-structured focus group was conducted with rehabilitation clinicians and those with lived experience of paediatric acquired brain injury (ABI). The 90-min focus group was audio-recorded and transcribed verbatim. Data were thematically coded and mapped against the Theoretical Domains Framework (TDF) to understand influencing factors, which were then linked to the Capability, Opportunity, Motivation - Behaviour (COM-B) model. Results A total of 11 participants (nine paediatric rehabilitation clinicians, one parent and one young person with lived experience of paediatric ABI) participated in the focus group. Factors influencing collaborative goal setting mapped to the COM-B and six domains of the TDF: Capabilities (Skills, Knowledge, Beliefs about capabilities, and Behavioural regulation), Opportunities (Environmental context and resources), and Motivation (Social/professional role and identity). Results suggest that a multifaceted intervention is needed to enhance rehabilitation clinicians' and families' skills and knowledge of goal setting, restructure the goal communication processes, and clarify the roles clinicians play in goal setting within the interdisciplinary team. Conclusion The use of the TDF and COM-B enabled a systematic approach to understanding the factors influencing goal setting for children with acquired brain injury in a large interdisciplinary rehabilitation team, and develop a targeted, multifaceted intervention for clinical use. These represent important considerations for the improvement of collaborative goal setting in paediatric rehabilitation services to ensure that best practice approaches to goal setting are implemented effectively in clinical practice.

Impact of Impedance Levels on Recording Quality in Flexible Neural Probes.

Flexible neural probes are attractive emerging technologies for brain recording because they can effectively record signals with minimal risk of brain damage. Reducing the electrode impedance of the probe before recording is a common practice of many researchers. However, studies investigating the impact of low impedance levels on high-quality recordings using flexible neural probes are lacking. In this study, we electrodeposited Pt onto a commercial flexible polyimide neural probe and investigated the relationship between the impedance level and the recording quality. The probe was inserted into the brains of anesthetized mice. The electrical signals of neurons in the brain, specifically the ventral posteromedial nucleus of the thalamus, were recorded at impedance levels of 50, 250, 500 and 1000 kΩ at 1 kHz. The study results demonstrated that as the impedance decreased, the quality of the signal recordings did not consistently improve. This suggests that extreme lowering of the impedance may not always be advantageous in the context of flexible neural probes.