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.

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.

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.

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.

Co-designing positive behaviour support (PBS+PLUS) training resources: a qualitative study of people with ABI, close-others, and clinicians' experiences.

Background Challenging behaviours are often a significant difficulty faced following acquired brain injury (ABI), for which PBS+PLUS (a Positive Behaviour Support framework) is an effective intervention. Clinicians report experiencing a range of barriers to supporting behaviour change for individuals with ABI and require tailored resources to support the implementation of PBS+PLUS. This study aimed to describe the process of co-designing a PBS+PLUS intervention guidebook and podcast series together with individuals with ABI, close-others, and clinicians, and qualitatively examine co-design experiences. Methods The Knowledge-To-Action Framework was followed to support the translation of PBS+PLUS into clinical practice. Participants with ABI (n = 4), close-others (n = 7), and clinicians (n = 3) participated in focus groups contributing to the development of a PBS+PLUS intervention guidebook and podcast series. Following completion of the groups, qualitative interviews were conducted to understand participants' perspectives of the co-design experience. Transcripts were analysed using reflexive thematic analysis. Results Co-design processes are described, and participants provided practical suggestions for co-design and the dissemination of developed resources. Two core themes encapsulating four sub-themes were identified. Firstly, 'Esteeming Experiences ' described the person-driven approach of co-design whereby participants felt supported and connected with other contributors and facilitators through sharing their perspectives. Secondly, 'Empowerment ' reflected participants' increased confidence and skills in applying PBS+PLUS. Conclusions Overall, participants endorsed the therapeutic benefits of co-design engagement and high utility of PBS+PLUS resources. This study adds to the growing literature supporting the use of co-design methodology within clinical implementation, and is inclusive of individuals with ABI, close-others, and clinicians.

"NeuroVanguard": a contemporary strategy in neuromonitoring for severe adult brain injury patients.

Severe acute brain injuries, stemming from trauma, ischemia or hemorrhage, remain a significant global healthcare concern due to their association with high morbidity and mortality rates. Accurate assessment of secondary brain injuries severity is pivotal for tailor adequate therapies in such patients. Together with neurological examination and brain imaging, monitoring of systemic secondary brain injuries is relatively straightforward and should be implemented in all patients, according to local resources. Cerebral secondary injuries involve factors like brain compliance loss, tissue hypoxia, seizures, metabolic disturbances and neuroinflammation. In this viewpoint, we have considered the combination of specific noninvasive and invasive monitoring tools to better understand the mechanisms behind the occurrence of these events and enhance treatment customization, such as intracranial pressure monitoring, brain oxygenation assessment and metabolic monitoring. These tools enable precise intervention, contributing to improved care quality for severe brain injury patients. The future entails more sophisticated technologies, necessitating knowledge, interdisciplinary collaboration and resource allocation, with a focus on patient-centered care and rigorous validation through clinical trials.

Co-developing 'The CyberABIlity Scale' to assess vulnerability to cyberscams for people with acquired brain injury: Delphi and cognitive interviews with clinicians and people with acquired brain injury.

Background Although individuals with acquired brain injury (ABI) may be vulnerable to cyberscams, the lack of existing measures documenting cybersafety behaviours in people with ABI limits our understanding of ABI-specific risk factors, the frequency of this problem, and the ability to evaluate evidence-based interventions. The CyberABIlity Scale was developed to assess vulnerability in people with ABI via self-rated statements and practical scam-identification tasks. This study aimed to develop and refine The CyberABIlity Scale through feedback from clinicians and people with ABI. Methods Scale feedback was collected via three rounds of clinician surveys (n = 14) using Delphi methods and two rounds of cognitive interviews with participants with ABI (n = 8). Following each round, feedback was quantitatively and qualitatively summarised, and revisions were made accordingly. Results Key revisions included removing 12 items deemed irrelevant. Instructions and rating scales were revised to improve clarity. Cognitive interviews identified 15 comprehension errors, with further revisions made to support response clarity for participants with ABI. Clinicians and participants with ABI endorsed the content and face validities of The CyberABIlity Scale . Conclusions Following further validation, The CyberABIlity Scale has the potential to be an effective screening measure for online vulnerability for people with ABI within clinical and research settings.

Understanding barriers and facilitators to long-term participation needs in children and young people following acquired brain injuries: a qualitative multi-stakeholder study.

Background This study focused on exploring the longer-term participation needs of children and young people with acquired brain injury (CYP-ABI) and their families in one region of the UK and identifying the barriers and facilitators of their participation and well-being to inform the development of a behavioural change intervention for clinical implementation. Methods Qualitative interviews were conducted with CYP-ABI and parents. Focus groups were created with health, education, care and charity stakeholders. The International Classification of Functioning, Disability and Health (ICF) and the Behaviour Change Wheel (BCW) were used to map needs, barriers and facilitators. Results A total of 10 CYP/parent dyads (n = 20) and 17 health, education, care and charity stakeholders were included in this study. Unmet participation needs were mapped to the ICF and barriers/facilitators to the BCW. Significant unmet needs impacting CYP-ABI participation and family well-being were found. Barriers spanned 'Capability', 'Opportunity' and 'Motivation', the greatest being knowledge, skills, social influences, environmental context and resources, social identity and emotion. Facilitators included increasing awareness and understanding, supporting parents, long-term access to specialist assessment and rehabilitation, peer support and integrated collaborative pathways. Conclusion The long-term impact of ABI on CYP and families' participation and well-being were significant, with barriers spanning every sector and level of society. Implementation of collaborative, cross-sector (education, health and social care) accessible and family-centred care pathways is needed to meet the long-term needs of CYP-ABI and their families, ensuring equity of access. Multi-modal, family-centred, needs-led, theory-based interventions should be co-developed with CYP, families and stakeholders to improve the health and well-being outcomes and the lives of CYP-ABI and their families.

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.

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.

The effectiveness and safety of centralized early rehabilitation care for critically ill children with severe acquired brain injury: A retrospective cohort and implementation study.

BACKGROUND: Most children with neurocritical illness are at risk of physical, neurocognitive, and psychosocial sequelae and need centralized early rehabilitation care. OBJECTIVE: To identify the effectiveness and safety of centralized early rehabilitation care for children with severe acquired brain injury. METHODS: This is a mixed methods study-an implementation study and single-center retrospective cohort study with historical control. All children with severe acquired brain injury hospitalized in a specialized rehabilitation center in a comprehensive tertiary pediatric hospital between September 2016 and August 2020 were included. Patients treated in the centralized early rehabilitation unit were compared to historical controls dispersed in the normal inpatient rehabilitation ward. The effectiveness outcomes were measured by the Pediatric Cerebral Performance Category (PCPC) scale and the incidence of newly onset comorbidities. The safety outcomes were indicated by the mortality rate and the incidence of unexpected referrals. RESULTS: One hundred seventy-five patients were included. The delta PCPC scores of the first 4 weeks of inpatient rehabilitation in the intervention group were significantly lower than the control group (Z = -2.395, p = 0.017). The PCPC scores at 1 year in the intervention group were significantly reduced as compared to the control group (Z = -3.337, p = 0.001). The incidence of newly onset pneumonia/bronchitis was also decreased in the intervention group (χ2 = 4.517, p = 0.034). No death of patients was recorded, and there was no significant difference in unexpected referral rate between the two groups (χ2 = 0.374, p = 0.541). CONCLUSIONS: The centralized pediatrics early rehabilitation unit is effective and safe for children with severe acquired brain injury. Further multicenter prospective implementation studies on effectiveness, safety, and economic evaluation are needed.