Preventive Effect of Low Intensity Pulsed Ultrasound against Experimental Cerebral Ischemia/Reperfusion Injury via Apoptosis Reduction and Brain-derived Neurotrophic Factor Induction

Neuromodulation with Ultrasound: Hypotheses on the Directionality of Effects and a Community Resource

Low-intensity Transcranial Ultrasound Stimulation (TUS) is a promising non-invasive technique for deep-brain stimulation and focal neuromodulation. Research with animal models and computational modelling has raised the possibility that TUS can be biased towards enhancing or suppressing neural function. Here, we first conduct a systematic review of human TUS studies for perturbing neural function and alleviating brain disorders. We then collate a set of hypotheses on the directionality of TUS effects and conduct an initial meta-analysis on the human TUS study reported outcomes to date ( n = 32 studies, 37 experiments). We find that parameters such as the duty cycle show some predictability regarding whether the targeted area's function is likely to be enhanced or suppressed. Given that human TUS sample sizes are exponentially increasing, we recognize that results can stabilize or change as further studies are reported. Therefore, we conclude by establishing an Iowa-Newcastle (inTUS) resource for the systematic reporting of TUS parameters and outcomes to support further hypothesis testing for greater precision in brain stimulation and neuromodulation with TUS.

Highlights

Systematic review of human TUS studies for enhancing or suppressing neural functionCollated set of hypotheses on using TUS to bias towards enhancement or suppressionMeta-analysis results identify parameters that may bias the directionality of effectsTUS resource established for systematic reporting of TUS parameters and outcomes.

Analysis and Regulatory Mechanisms of Platelet-Related Genes in Patients with Ischemic Stroke

It was found that ischemic stroke (IS) was associated with abnormal platelet activity and thrombosis. However, the potential significance of platelet-related genes (PRGs) in IS still needs to be more thorough. This study extracted IS-related transcriptome datasets from the Gene Expression Omnibus (GEO) database. The target genes were obtained by intersecting the differentially expressed genes (DEGs), the module genes related to IS, and PRGs, where the key genes of IS were screened by two machine learning algorithms. The key genes-based diagnostic model was constructed. Gene set enrichment analysis (GSEA) and the immune microenvironment analyses were analyzed targeting key genes in IS. The co-expression, TF-mRNA, and competitive endogenous RNAs (ceRNA) regulatory networks were constructed to reveal the potential regulation of key genes. Potential drugs targeting key genes were predicted as well. Totals of eight target genes were obtained and were associated with immune-related functions. Four platelet-related key genes were acquired, which were related to immunity and energy metabolism. The abnormal expressions of DOCK8, GIMAP5, ICOS were determined by the quantitative real-time polymerase chain reaction (qRT-PCR), and the significant correlations among these key genes were identified. Notably, hsa-miR-17-3p, hsa-miR-3158-3p, hsa-miR-423-3p, and hsa-miR-193a-8p could regulate all key genes at the same time. In addition, Caffeine, Carboplatin, and Vopratelimab were the targeted drugs of these key genes. This study identified four platelet-related key genes of IS, which might help to deepen the understanding of the role of platelet-related genes in the molecular mechanism of IS.

Low-intensity pulsed ultrasound of different intensities differently affects myocardial ischemia/reperfusion injury by modulating cardiac oxidative stress and inflammatory reaction

Introduction

The prevalence of ischemic heart disease has reached pandemic levels worldwide. Early revascularization is currently the most effective therapy for ischemic heart diseases but paradoxically induces myocardial ischemia/reperfusion (MI/R) injury. Cardiac inflammatory reaction and oxidative stress are primarily involved in the pathology of MI/R injury. Low-intensity pulsed ultrasound (LIPUS) has been demonstrated to reduce cell injury by protecting against inflammatory reaction and oxidative stress in many diseases, including cardiovascular diseases, but rarely on MI/R injury.

Methods

This study was designed to clarify whether LIPUS alleviates MI/R injury by alleviating inflammatory reaction and oxidative stress. Simultaneously, we have also tried to confirm which intensity of the LIPUS might be more suitable to ameliorate the MI/R injury, as well as to clarify the signaling mechanisms. MI/R and simulated ischemia/reperfusion (SI/R) were respectively induced in Sprague Dawley rats and human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs). LIPUS treatment, biochemical measurements, cell death assay, estimation of cardiac oxidative stress and inflammatory reaction, and protein detections by western blotting were performed according to the protocol.

Results

In our study, both in vivo and in vitro, LIPUS of 0.1 W/cm2 (LIPUS0.1) and 0.5 W/cm2 (LIPUS0.5) make no significant difference in the cardiomyocytes under normoxic condition. Under the hypoxic condition, MI/R injury, inflammatory reaction, and oxidative stress were partially ameliorated by LIPUS0.5 but were significantly aggravated by LIPUS of 2.5 W/cm2 (LIPUS2.5) both in vivo and in vitro. The activation of the apoptosis signal-regulating kinase 1 (ASK1)/c-Jun N-terminal kinase (JNK) pathway in cardiomyocytes with MI/R injury was partly rectified LIPUS0.5 both in vivo and in vitro.

Conclusion

Our study firstly demonstrated that LIPUS of different intensities differently affects MI/R injury by regulating cardiac inflammatory reaction and oxidative stress. Modulations on the ASK1/JNK pathway are the signaling mechanism by which LIPUS0.5 exerts cardioprotective effects. LIPUS0.5 is promising for clinical translation in protecting against MI/R injury. This will be great welfare for patients suffering from MI/R injury.

Low-intensity pulsed ultrasound ameliorates glia-mediated inflammation and neuronal damage in experimental intracerebral hemorrhage conditions

BACKGROUND

Intracerebral hemorrhage (ICH) is a condition associated with high morbidity and mortality, and glia-mediated inflammation is a major contributor to neurological deficits. However, there is currently no proven effective treatment for clinical ICH. Recently, low-intensity pulsed ultrasound (LIPUS), a non-invasive method, has shown potential for neuroprotection in neurodegenerative diseases. This study aimed to investigate the neuroprotective effects and potential mechanisms of LIPUS on glia-mediated inflammation in ICH.

METHODS

This study used 289 mice to investigate the effects of LIPUS on ICH. ICH was induced by injecting bacterial collagenase (type VII-S; 0.0375 U) into the striatum of the mice. LIPUS was applied noninvasively for 3 days, including a 2-h-delayed intervention to mimic clinical usage. The study evaluated neurological function, histology, brain water content, hemoglobin content, MRI, and protein expression of neurotrophic factors, inflammatory molecules, and apoptosis. In vitro studies investigated glia-mediated inflammation by adding thrombin (10 U/mL) or conditioned media to primary and cell line cultures. The PI3K inhibitor LY294002 was used to confirm the effects of PI3K/Akt signaling after LIPUS treatment.

RESULTS

LIPUS treatment improved neurological deficits and reduced tissue loss, edema, and neurodegeneration after ICH. The protective effects of LIPUS resulted from decreased glia-mediated inflammation by inhibiting PI3K/Akt-NF-κB signaling, which reduced cytokine expression and attenuated microglial activation-induced neuronal damage in vitro.

CONCLUSIONS

LIPUS treatment improved neurological outcomes and reduced glia-mediated inflammation by inhibiting PI3K/Akt-NF-κB signaling after ICH. LIPUS may provide a non-invasive potential management strategy for ICH.

Research Progress of Low-Intensity Pulsed Ultrasound in the Repair of Peripheral Nerve Injury

Peripheral nerve injury (PNI) is a common disease that has profound impact on the health of patients, but has poor prognosis. The gold standard for the treatment of peripheral nerve defects is autologous nerve grafting; notwithstanding, due to the extremely high requirement for surgeons and medical facilities, there is great interest in developing better treatment strategies for PNI. Low-intensity pulsed ultrasound (LIPUS) is a noninterventional stimulation method characterized by low-intensity pulsed waves. It has good therapeutic effect on fractures, inflammation, soft tissue regeneration, and nerve regulation, and can participate in PNI repair from multiple perspectives. This review concentrates on the effects and mechanisms of LIPUS in the repair of PNI from the perspective of LIPUS stimulation of neural cells and stem cells, modulation of neurotrophic factors, signaling pathways, proinflammatory cytokines, and nerve-related molecules. In addition, the effects of LIPUS on nerve conduits are reviewed, as nerve conduits are expected to be a successful alternative treatment for PNI with the development of tissue engineering. Overall, the application advantages and prospects of LIPUS in the repair of PNI are highlighted by summarizing the effects of LIPUS on seed cells, neurotrophic factors, and nerve conduits for neural tissue engineering.

Low-intensity pulsed ultrasound in obstetrics and gynecology: advances in clinical application and research progress

In the past decade, research on ultrasound therapy in obstetrics and gynecology has rapidly developed. Currently, high-intensity ultrasound has been widely used in clinical practice, while low-intensity ultrasound has gradually emerged as a new trend of transitioning from pre-clinical research to clinical applications. Low-intensity pulsed ultrasound (LIPUS), characterized by a non-invasive low-intensity pulse wave stimulation method, employs its non-thermal effects to achieve safe, economical, and convenient therapeutic outcomes. LIPUS converts into biochemical signals within cells through pathways such as cavitation, acoustic flow, and mechanical stimulation, regulating molecular biological mechanisms and exerting various biological effects. The molecular biology mechanisms underlying the application of LIPUS in obstetrics and gynecology mainly include signaling pathways, key gene expression, angiogenesis, inflammation inhibition, and stem cell differentiation. LIPUS plays a positive role in promoting soft tissue regeneration, bone regeneration, nerve regulation, and changes in cell membrane permeability. LIPUS can improve the treatment benefit of premature ovarian failure, pelvic floor dysfunction, nerve damage caused by intrauterine growth restriction, ovariectomized osteoporosis, and incomplete uterine involution through the above biological effects, and it also has application value in the adjuvant treatment of malignant tumors such as ovarian cancer and cervical cancer. This study outlines the biological mechanisms and applications of LIPUS in treating various obstetric and gynecologic diseases, aiming to promote its precise application and provide a theoretical basis for its use in the field.

Low-Intensity Ultrasound Reduces Brain Infarct Size by Upregulating Phosphorylated Endothelial Nitric Oxide in Mouse Model of Middle Cerebral Artery Occlusion

OBJECTIVE

There have been attempts to use therapeutic ultrasound (US) for the treatment of both experimental and clinical stroke. We hypothesized that low-intensity US has direct beneficial effects on the brain independent of cerebral blood flow (CBF) during middle cerebral artery occlusion (MCAO).

METHODS

Three groups of mice were studied. Group I included 84 mice with MCAO undergoing US treatment/no treatment at two US frequencies (0.25 and 1.05 MHz) with three different acoustic pressures at each frequency in which infarct size (IS) was measured 24 h later. Group II included 11 mice undergoing treatment based on best US results from group I animals in which the IS/risk area (RA) ratio was measured 24 h later. Group III included 38 normal mice undergoing US treatment/no treatment for assessment of CBF, tissue metabolite and protein expression and histopathology.

DISCUSSION

Ultrasound at both frequencies and most acoustic pressures resulted in reduction in IS in group I animals, with the best results obtained with 0.25 MHz at 2.0 MPa: IS was reduced 4-fold in the cerebral cortex, 1.5-fold in the caudate putamen and 3.5-fold in the cerebral hemisphere compared with control. US application in group III animals elicited only a marginal increase in CBF despite a 2.6-fold increase in phosphorylated endothelial nitric oxide synthase (p-eNOS)-S1177 and a corresponding decrease in p-eNOS-T494. Histopathology revealed no evidence of hemorrhage, inflammation or necrosis.

CONCLUSION

Low-intensity US at specific frequencies and acoustic pressures results in marked neuroprotection in a mouse model of stroke by modulation of p-eNOS independent of its effect on CBF.

Low-Intensity Focused Ultrasound Neuromodulation for Stroke Recovery: A Novel Deep Brain Stimulation Approach for Neurorehabilitation?

Stroke as the leading cause of adult long-term disability and has a significant impact on patients, society and socio-economics. Non-invasive brain stimulation (NIBS) approaches such as transcranial magnetic stimulation (TMS) or transcranial electrical stimulation (tES) are considered as potential therapeutic options to enhance functional reorganization and augment the effects of neurorehabilitation. However, non-invasive electrical and magnetic stimulation paradigms are limited by their depth focality trade-off function that does not allow to target deep key brain structures critically important for recovery processes. Transcranial ultrasound stimulation (TUS) is an emerging approach for non-invasive deep brain neuromodulation. Using non-ionizing, ultrasonic waves with millimeter-accuracy spatial resolution, excellent steering capacity and long penetration depth, TUS has the potential to serve as a novel non-invasive deep brain stimulation method to establish unprecedented neuromodulation and novel neurorehabilitation protocols. The purpose of the present review is to provide an overview on the current knowledge about the neuromodulatory effects of TUS while discussing the potential of TUS in the field of stroke recovery, with respect to existing NIBS methods. We will address and discuss critically crucial open questions and remaining challenges that need to be addressed before establishing TUS as a new clinical neurorehabilitation approach for motor stroke recovery.

The Implications of Microglial Regulation in Neuroplasticity-Dependent Stroke Recovery

Stroke causes varying degrees of neurological deficits, leading to corresponding dysfunctions. There are different therapeutic principles for each stage of pathological development. Neuroprotection is the main treatment in the acute phase, and functional recovery becomes primary in the subacute and chronic phases. Neuroplasticity is considered the basis of functional restoration and neurological rehabilitation after stroke, including the remodeling of dendrites and dendritic spines, axonal sprouting, myelin regeneration, synapse shaping, and neurogenesis. Spatiotemporal development affects the spontaneous rewiring of neural circuits and brain networks. Microglia are resident immune cells in the brain that contribute to homeostasis under physiological conditions. Microglia are activated immediately after stroke, and phenotypic polarization changes and phagocytic function are crucial for regulating focal and global brain inflammation and neurological recovery. We have previously shown that the development of neuroplasticity is spatiotemporally consistent with microglial activation, suggesting that microglia may have a profound impact on neuroplasticity after stroke and may be a key therapeutic target for post-stroke rehabilitation. In this review, we explore the impact of neuroplasticity on post-stroke restoration as well as the functions and mechanisms of microglial activation, polarization, and phagocytosis. This is followed by a summary of microglia-targeted rehabilitative interventions that influence neuroplasticity and promote stroke recovery.

Ultrasound as a versatile tool for short- and long-term improvement and monitoring of brain function

Treating the brain with focused ultrasound (FUS) at low intensities elicits diverse responses in neurons, astroglia, and the extracellular matrix. In combination with intravenously injected microbubbles, FUS also opens the blood-brain barrier (BBB) and facilitates focal drug delivery. However, an incompletely understood cellular specificity and a wide parameter space currently limit the optimal application of FUS in preclinical and human studies. In this perspective, we discuss how different FUS modalities can be utilized to achieve short- and long-term improvements, thereby potentially treating brain disorders. We review the ongoing efforts to determine which parameters induce neuronal inhibition versus activation and how mechanoreceptors and signaling cascades are activated to induce long-term changes, including memory improvements. We suggest that optimal FUS treatments may require different FUS modalities and devices, depending on the targeted brain area or local pathology, and will be greatly enhanced by new techniques for monitoring FUS efficacy.

Dual-frequency ultrasound enhances functional neuron differentiation from neural stem cells by modulating Ca2+ dynamics and the ERK1/2 signaling pathway

Our previous study demonstrated that ultrasound is able to promote differentiation on neural stem cells (NSCs), and dual-frequency ultrasound promotes this effect due to enhanced acoustic cavitation compared with single-frequency ultrasound. However, the underlying biological reasons have not been well disclosed. The purpose of this study was to investigate the underlying bioeffects, mechanisms and signaling pathways of dual-frequency ultrasound on NSC differentiation. The morphology, neurite outgrowth, and differentiation percentages were investigated under various dual-frequency simulation parameters with exposure periods varying from 5 to 15 min. Morphological observations identified that dual-frequency ultrasound stimulation promoted ultrasound dose-dependent neurite outgrowth. In particular, cells exposed for 10 min/2 days showed optimal neurite outgrowth and neuron differentiation percentages. In addition, live cell calcium images showed that dual-frequency ultrasound enhanced the internal calcium content of the cells, and calcium ions entering cells from the extracellular environment could be observed. Dual frequency ultrasound exposure enhanced extracellular calcium influx and upregulated extracellular signal-regulated kinases 1/2 (ERK1/2) expression. Observations from immunostaining and protein expression examinations also identified that dual-frequency ultrasound promoted brain-derived neurotrophic factor (BDNF) secretion from astrocytes derived from NSCs. In summary, evidence supports that dual-frequency ultrasound effectively enhances functional neuron differentiation via calcium channel regulation via the downstream ERK1/2 pathway and promotes BDNF secretion to serve as feedback to cascade neuron differentiation. The results may provide an alternative for cell-based therapy in brain injury.

Modulation effect of low-intensity transcranial ultrasound stimulation on REM and NREM sleep

Previous studies have shown that modulating neural activity can affect rapid eye movement (REM) and non-rapid eye movement (NREM) sleep. Low-intensity transcranial ultrasound stimulation (TUS) can effectively modulate neural activity. However, the modulation effect of TUS on REM and NREM sleep is still unclear. In this study, we used ultrasound to stimulate motor cortex and hippocampus, respectively, and found the following: (i) In healthy mice, TUS increased the NREM sleep ratio and decreased the REM sleep ratio, and altered the relative power and sample entropy of the delta band and spindle in NREM sleep and that of the theta and gamma bands in REM sleep. (ii) In sleep-deprived mice, TUS decreased the ratio of REM sleep or the relative power of the theta band during REM sleep. (iii) In sleep-disordered Alzheimer’s disease (AD) mice, TUS increased the total sleep time and the ratio of NREM sleep and modulated the relative power and the sample entropy of the delta and spindle bands during NREM and that of the theta band during REM sleep. These results demonstrated that TUS can effectively modulate REM and NREM sleep and that modulation effect depends on the sleep state of the samples, and can improve sleep in sleep-disordered AD mice.

Preventive and Therapeutic Effects of Low-Intensity Ultrasound Stimulation on Migraine in Rats

This study sought to systematically evaluate the prophylactic and therapeutic effects of low-intensity transcranial ultrasound stimulation on migraine in rats. We used video recordings to assess the head scratching behavior and laser speckle contrast imaging to record the changes in cerebral blood flow velocity of freely moving rats in a healthy group, migraine group, migraine group with ultrasound prevention, and migraine group with ultrasound therapy. Results demonstrated that (1) head scratching during migraine attacks in rats was accompanied by an decrease in cerebral blood flow; (2) both ultrasound prevention and therapy significantly reduced the number of head scratches but did not reduce the cerebral blood flow velocity; and (3) the number of head scratches in the ultrasound stimulation groups was not affected by the auditory effect. These results reveal that low-intensity ultrasound has the potential to be used clinically in the prevention and therapeutic treatment of migraine.

Transcranial ultrasound stimulation applied in ischemic stroke rehabilitation: A review

Ischemic stroke is a serious medical condition that is caused by cerebral vascular occlusion and leads to neurological dysfunction. After stroke, patients suffer from long-term sensory, motor and cognitive impairment. Non-invasive neuromodulation technology has been widely studied in the field of stroke rehabilitation. Transcranial ultrasound stimulation (TUS), as a safe and non-invasive technique with deep penetration ability and a tiny focus, is an emerging technology. It can produce mechanical and thermal effects by delivering sound waves to brain tissue that can induce the production of neurotrophic factors (NFs) in the brain, and reduce cell apoptosis and the inflammatory response. TUS, which involves application of an acoustic wave, can also dissolve blood clots and be used to deliver therapeutic drugs to the ischemic region. TUS has great potential in the treatment of ischemic stroke. Future advancements in imaging and parameter optimization will improve the safety and efficacy of this technology in the treatment of ischemic stroke.

Early Warning of Ischemic Stroke Based on Atherosclerosis Index Combined With Serum Markers

CONTEXT

Ischemic stroke (IS) is a serious public health problem worldwide, threatening human life and health. Atherosclerosis is the cause of stroke. At present, there are few selective indexes that can be used to evaluate atherosclerosis in the clinic; providers rely mainly on the atherosclerotic index (AI). Disturbance of lipid metabolism is considered to be a key event leading to IS.

OBJECTIVE

The purpose of this study was to discover potential biomarkers in the serum of atherosclerosis-induced IS, combined with the AI to provide early warning for the diagnosis of IS.

METHODS

In this study, we used nontargeted metabolomics based on ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS) to measure the changes in serum metabolites in a group of patients with IS. To verify the reproducibility of candidate biomarkers in the population, we expanded the sample size.

RESULTS

Five metabolites were identified, including sphingomyelin (18:0/14:0), 1-Methylpyrrolinium, PC (18:0/18:0), LysoPC (18:0/0:0), and PC (18: 2/18:2). The combination of these 5 metabolic markers has good diagnostic and predictive ability, and the change level of these metabolites is significantly related to IS. Our results also indicate that changes in glycerophospholipid metabolism may indicate an early risk of IS development.

CONCLUSION

These findings may contribute to the development of new diagnostic methods of potential biomarkers in serum combined with the AI, thereby providing early warning for the diagnosis of atherosclerosis-induced IS, and may provide a new insights for pathogenesis in IS.

The Updated Role of Transcranial Ultrasound Neuromodulation in Ischemic Stroke: From Clinical and Basic Research

Ischemic stroke is a common cause of death and disability worldwide, which leads to serious neurological and physical dysfunction and results in heavy economic and social burdens. For now, timely and effective dissolution of thrombus, and ultimately improvement in the recovery of neurological functions, is the treatment strategy focus. Recently, many studies have reported that transcranial ultrasound stimulation (TUS), as a non-invasive method, can dissolve thrombus, improve cerebral blood circulation, and exert a neuroprotective effect post-stroke. TUS can promote functional recovery and improve rehabilitation efficacy among patients with ischemic stroke. This mini-review summarizes the potential mechanism and limitation of TUS in stroke aims to provide a new strategy for the future treatment of patients with ischemic stroke.

The Genetic Basis of Strokes in Pediatric Populations and Insight into New Therapeutic Options

Strokes within pediatric populations are considered to be the 10th leading cause of death in the United States of America, with over half of such events occurring in children younger than one year of life. The multifactorial etiopathology that has an influence on stroke development and occurrence signify the importance of the timely recognition of both modifiable and non-modifiable factors for adequate diagnostic and treatment approaches. The early recognition of a stroke and stroke risk in children has the potential to advance the application of neuroprotective, thrombolytic, and antithrombotic interventions and rehabilitation strategies to the earliest possible timepoints after the onset of a stroke, improving the outcomes and quality of life for affected children and their families. The recent development of molecular genetic methods has greatly facilitated the analysis and diagnosis of single-gene disorders. In this review, the most significant single gene disorders associated with pediatric stroke are presented, along with specific therapeutic options whenever they exist. Besides monogenic disorders that may present with stroke as a first symptom, genetic polymorphisms may contribute to the risk of pediatric and perinatal stroke. The most frequently studied genetic risk factors are several common polymorphisms in genes associated with thrombophilia; these genes code for proteins that are part of the coagulation cascade, fibrolysis, homocystein metabolism, lipid metabolism, or platelets. Single polymorphism frequencies may not be sufficient to completely explain the stroke causality and an analysis of several genotype combinations is a more promising approach. The recent steps forward in our understanding of the disorders underlying strokes has given us a next generation of therapeutics and therapeutic targets by which to improve stroke survival, protect or rebuild neuronal connections in the brain, and enhance neural function. Advances in DNA sequencing and the development of new tools to correct human gene mutations have brought genetic analysis and gene therapy into the focus of investigations for new therapeutic options for stroke patients.

Bioactive Flavonoids Icaritin and Icariin Protect against Cerebral Ischemia-Reperfusion-Associated Apoptosis and Extracellular Matrix Accumulation in an Ischemic Stroke Mouse Model

Stroke, which is the second leading cause of mortality in the world, is urgently needed to explore the medical strategies for ischemic stroke treatment. Both icariin (ICA) and icaritin (ICT) are the major active flavonoids extracted from Herba epimedii that have been regarded as the neuroprotective agents in disease models. In this study, we aimed to investigate and compare the neuroprotective effects of ICA and ICT in a middle cerebral artery occlusion (MCAO) mouse model. Male ICR mice were pretreated with both ICA and ICT, which ameliorated body weight loss, neurological injury, infarct volume, and pathological change in acute ischemic stroke mice. Furthermore, administration of both ICA and ICT could also protect against neuronal cell apoptotic death, oxidative and nitrosative stress, lipid peroxidation, and extracellular matrix (ECM) accumulation in the brains. The neuroprotective effects of ICT are slightly better than that of ICA in acute cerebral ischemic stroke mice. These results suggest that pretreatment with both ICA and ICT improves the neuronal cell apoptosis and responses of oxidative/nitrosative stress and counteracts the ECM accumulation in the brains of acute cerebral ischemic stroke mice. Both ICA and ICT treatment may serve as a useful therapeutic strategy for acute ischemic stroke.

The Role of Ultrasound as a Diagnostic and Therapeutic Tool in Experimental Animal Models of Stroke: A Review

Ultrasound is a noninvasive technique that provides real-time imaging with excellent resolution, and several studies demonstrated the potential of ultrasound in acute ischemic stroke monitoring. However, only a few studies were performed using animal models, of which many showed ultrasound to be a safe and effective tool also in therapeutic applications. The full potential of ultrasound application in experimental stroke is yet to be explored to further determine the limitations of this technique and to ensure the accuracy of translational research. This review covers the current status of ultrasound applied to monitoring and treatment in experimental animal models of stroke and examines the safety, limitations, and future perspectives.

Effects of Low-Intensity Transcranial Pulsed Ultrasound Treatment in a Model of Alzheimer's Disease

Alzheimer's disease (AD) is the most common neurodegenerative disease. One of the main pathology markers of AD is the beta-amyloid plaques (βA_1-42) created from residues of the badly processed amyloid precursor protein. The accumulation of these plaques can induce neuroinflammation and oxidative stress and impair antioxidant mechanisms, culminating in cognitive and memory deficits. New therapies are necessary to treat AD as the approved drugs do not treat the progress of the disease. Transcranial low-intensity pulsed ultrasound (LIPUS) affects brain metabolism and could be tested as a treatment for AD. This study was aimed at evaluating the LIPUS treatment in a model of AD induced by βA_1-42 intracerebroventricularly (ICV) and its effects on learning memory, neurotrophins, neuroinflammation and oxidative status. βA_1-42 was administered ICV 24 h before the start of a 5-wk LIPUS treatment. The treatment with LIPUS improved recognition memory, as well as increasing nerve growth factor β and brain-derived neurotrophic factor levels in the hippocampus and cortex. There was a decrease in protein damage in the hippocampus treated with LIPUS. Neuroinflammation and oxidative stress were not present in the AD model used. The results indicated that LIPUS is a novel and promising adjuvant strategy for treatment of the late stage of AD.

Low-Intensity Pulsed Ultrasound Stimulation Inhibits Cortical Spreading Depression

Cortical spreading depression (CSD), which is closely correlated with migraine aura, cerebral ischemia, seizure, and brain injury, is a spreading wave of neuronal and glial depolarization. The purpose of this study is to investigate whether low-intensity pulsed ultrasound stimulation (PUS) inhibits CSD by modulating neural activity and hemodynamics. Behavioral test, intrinsic signal optical imaging and western blot analysis were used for evaluating the inhibition effect of PUS on CSD in rat. We found that: 1) 30 min of PUS can significantly improve motor activity of rat with CSD. 2) Both 30 s and 30 min of PUS can significantly reduce count and propagation speed of CSD in rat and the inhibitory effect was enhanced with increase of ultrasound intensity. 3) 30 min of PUS significantly enhanced levels of brain-derived neurotrophic factor protein in brain tissue with CSD. These results suggest that PUS has the potential to treat brain disorders associated with CSD.

Wearable Transcranial Ultrasound System for Remote Stimulation of Freely Moving Animal

OBJECTIVE

Transcranial focused ultrasound (tFUS) has drawn considerable attention in the neuroscience field as a noninvasive approach to modulate brain circuits. However, the conventional approach requires the use of anesthetized or immobilized animal models, which places considerable restrictions on behavior and affects treatment. Thus, this work presents a wireless, wearable system to achieve ultrasound brain stimulation in freely behaving animals.

METHODS

The wearable tFUS system was developed based on a microcontroller and amplifier circuit. Brain activity induced by tFUS was monitored through cerebral hemodynamic changes using near-infrared spectroscopy. The system was also applied to stroke rehabilitation after temporal middle cerebral artery occlusion (tMCAO) in rats. Temperature calculations and histological results showed the safety of the application even with prolonged 40 min sonication.

RESULTS

The output ultrasonic wave produced from a custom PZT transducer had a central frequency of 457 kHz and peak to peak pressure of 426 kPa. The device weight was 20 g, allowing a full range of motion. The stimulation was found to induce hemodynamic changes in the sonicated area, while open-field tests showed that ultrasound applied to the ipsilateral hemisphere for 5 consecutive days after the stroke facilitated recovery.

CONCLUSION

The wearable tFUS system has been designed and implemented on moving rats. The results showed the ability of device to cause both short- and long lasting effects.

SIGNIFICANCE

The proposed device provides a more natural environment to investigate the effects of tFUS for behavioral and long-term studies.

Antenatal low-intensity pulsed ultrasound reduces neurobehavioral deficits and brain injury following dexamethasone-induced intrauterine growth restriction

Intrauterine growth restriction (IUGR) is a leading cause of perinatal mortality and morbidity, and IUGR survivors are at increased risk of neurodevelopmental deficits. No effective interventions are currently available to improve the structure and function of the IUGR brain before birth. This study investigated the protective effects of low‐intensity pulsed ultrasound (LIPUS) on postnatal neurodevelopmental outcomes and brain injury using a rat model of IUGR induced by maternal exposure to dexamethasone (DEX). Pregnant rats were treated with DEX (200 μg/kg, s.c.) and LIPUS daily from gestational day (GD) 14 to 19. Behavioral assessments were performed on the IUGR offspring to examine neurological function. Neuropathology, levels of neurotrophic factors, and CaMKII‐Akt‐related molecules were assessed in the IUGR brain, and expression of glucose and amino acid transporters and neurotrophic factors were examined in the placenta. Maternal LIPUS treatment increased fetal weight, fetal liver weight, and placental weight following IUGR. LIPUS treatment also increased neuronal number and myelin protein expression in the IUGR brain, and attenuated neurodevelopmental deficits at postnatal day (PND) 18. However, the number of oligodendrocytes or microglia was not affected. These changes were associated with the upregulation of brain‐derived neurotrophic factor (BDNF) and placental growth factor (PlGF) protein expression, and enhancement of neuronal CaMKII and Akt activation in the IUGR brain at PND 1. Additionally, LIPUS treatment promoted glucose transporter (GLUT) 1 production and BDNF expression in the placenta, but had no effects on GLUT3 or amino acid transporter expression. Our findings suggest that antenatal LIPUS treatment may reduce IUGR‐induced brain injury via enhancing cerebral BDNF/CaMKII/Akt signaling. These data provide new evidence that LIPUS stimulation could be considered for antenatal neuroprotective therapy in IUGR.

Virtual reality for limb motor function, balance, gait, cognition and daily function of stroke patients: A systematic review and meta-analysis

AIMS

To explore the beneficial effects of virtual reality (VR) interventions on upper- and lower-limb motor function, balance, gait, cognition and daily function outcomes in stroke patients.

DESIGN

A systematic review and meta-analysis of randomized controlled trials.

DATA SOURCES

English databases (PubMed, EMBASE, the Cochrane Library, CINAHL, Web of Science, Physiotherapy Evidence Database, ProQuest Dissertations and Theses) and Chinese databases (Chinese BioMedical Literature Service System, WANFANG, CNKI) and the Clinical Trial Registry Platform were systematically searched from inception until December 2019. Additionally, reference lists of the included studies were manually searched.

REVIEW METHODS

The methodological quality of studies was scored with the Cochrane 'risk-of-bias tool' and PEDro scale from the Physiotherapy Evidence Database by two independent evaluators.

RESULTS

In total, 87 studies with 3540 participants were included. Stroke patients receiving VR interventions showed significant improvements in Fugl-Meyer assessment of Upper Extremity, Action Research Arm Test, Wolf Motor Function Test, Fugl-Meyer Assessment of Lower Extremity, Functional Ambulation Classification, Berg Balance Scale, Time Up and Go, Velocity, Cadence, Modified Barthel Index and Functional Independence Measure. However, differences between VR intervention and traditional rehabilitation groups were not significant for Box-Block Test, 10 m Walk Test, Auditory Continuous Performance Test, Mini-Mental State Examination and Visual Continuous Performance Test.

CONCLUSION

This review suggests that VR interventions effectively improve upper- and lower-limb motor function, balance, gait and daily function of stroke patients, but have no benefits on cognition.

IMPACT

This review identified the positive effects of VR-assisted rehabilitation on upper- and lower-limb motor function, balance, gait and daily function of stroke patients. And, we verified the duration of VR intervention affects some health benefits. The benefit of VR on cognitive function requires further investigation through large-scale multicentre RCTs.

Low-intensity pulsed ultrasound therapy promotes recovery from stroke by enhancing angio-neurogenesis in mice in vivo

Since the treatment window of thrombolytic therapy for stroke is limited, new therapy remains to be developed. We have recently developed low-intensity pulsed ultrasound (LIPUS) therapy to improve cognitive dysfunction in mouse models of vascular dementia and Alzheimer’s disease. Here, we further aimed to examine whether our LIPUS therapy improves neurological recovery from ischemic stroke, and if so, to elucidate the mechanisms involved. In a mouse model of middle cerebral artery occlusion (MCAO), we applied LIPUS (32 cycles, 193 mW/cm²) to the whole brain 3 times in the first week (days 1, 3, and 5) after MCAO. We evaluated neurological functions using behavioral tests and performed histological analyses. Furthermore, to elucidate how LIPUS works within the injured brain, we also tested the effects of LIPUS in endothelial nitric oxide synthase (eNOS)-deficient (eNOS^−/−) mice. In wild-type mice, the LIPUS therapy markedly improved neurological functions in the tightrope and rotarod tests at 28 days after MCAO. Histological analyses showed that the LIPUS therapy significantly increased the numbers of CD31-positive blood vessels in the perifocal lesion and doublecortin (DCX)-positive neurons in the ischemic striatum, indicating the angio-neurogenesis effects of the therapy. Importantly, these beneficial effects of the LIPUS therapy were totally absent in eNOS^−/− mice. No adverse effects of the LIPUS therapy were noted. These results indicate that the LIPUS therapy improves neurological functions after stroke through enhanced neuro-angiogenesis in mice in vivo in an eNOS-dependent manner, suggesting that it could a novel and non-invasive therapeutic option for stroke.

Effect of Low Intensity Transcranial Ultrasound (LITUS) on Post-traumatic Brain Edema in Rats: Evaluation by Isotropic 3-Dimensional T2 and Multi-TE T2 Weighted MRI

Background: Brain edema is one of the important factors affecting the prognosis of traumatic brain injury (TBI). Low-intensity transcranial ultrasound (LITUS) has significant anti-cerebral edema effect. T2-weighted image-based volume and T2 value measurements can sensitively reflect tissue edema.

Purpose: To evaluate the effect and possible mechanisms of LITUS on brain edema by iso-voxel 3-dimensional T2WI (iso-3D T2WI) and multi-TE T2WI. Methods: Forty-five rats were randomly divided into sham control, TBI and TBI + LITUS groups (n = 15, respectively). Iso-voxel 3-dimensional T2WI and multi-TE T2WI sequences at 3.0T to obtain T2 value and edema volume of the injury cortex. T2 values were obtained on days 1, 7, 14, 21, 28, 35, and 42 after TBI and brain edema volume were obtained on days 7 and 14.

Results: The T2 values of the damaged cortex in the TBI group showed a slow decreasing trend after a significant increase. For TBI+LITUS group, T2 values decreased with continuous LITUS treatment. At day 28, the T2 values were not significantly longer than the control group (adjusted P = 0.0535), but were significantly shorter than the TBI group at day 42 (adjusted P = 0.0003). The edema volume at day 7 and 14 in the LITUS group was significantly lower than the TBI group (P = 0.0004 and P < 0.0001, respectively). AQP-4 and β-APP protein staining showed a strong positive reaction near the CCI point, TBI+LITUS group showed a medium positive reaction, and the sham control group showed a weak positive reaction.

Conclusion: The therapeutic effect of LITUS on post-traumatic brain edema was confirmed through T2 value and edema volume, and the mechanism may be related to inhibiting the expression of AQP-4 and promoting the removal of β-APP.

Neuroprotective Effects of Anti-proBDNF in a Rat Photothrombotic Ischemic Model

Up-regulation of proBDNF in ischemic brain and the detrimental role of proBDNF on cellular survival has already been established. We propose that the up-regulated proBDNF may trigger the harmful events and evoke a secondary ischemic damage after ischemia. This study aimed to establish the neuroprotective effects of anti-proBDNF antibody in a rat photothrombotic ischemic model. Photothrombotic ischemic model was performed on Sprague Dawley rats and anti-proBDNF antibodies were administered intraperitoneally to the ischemic rats at a dose of 5 mg/kg after 6 hours (6 h) and on 3 days (3d) after ischemia. Behavioural tests were performed for sensorimotor functional analyses. Animals were euthanized at 7d for histochemical and biochemical studies. We observed higher proBDNF expression around the ischemic infarct. Higher level of apoptosis and inflammation was evident at 7d after ischemia on brain sections. Interestingly, the anti-proBDNF treatment instigated significant reduction of the infarction size as detected by Haematoxylin and Eosin (H&E) staining. Similar reduction of apoptotic signaling proteins in western blot and immunostaining after anti-proBDNF treatment was found. Up-regulation of synaptic protein expression was also observed after this treatment. Significant sensorimotor functional improvements were also noticed at 7d after anti-proBDNF treatment. We conclude that anti-proBDNF treatment is anti-apoptotic and anti-inflammatory, and plays advantageous role in promoting cellular growth and improving sensorimotor function after ischemic insult. Taken together, our study suggests that this anti-proBDNF treatment can be considered as a therapeutic approach for ischemic recovery.

Safety Assessment of a Wearable Low-Intensity Pulsed Ultrasound Device for Relieving Mental Illness Symptoms

Depression is expected to be one of the significant global medical burdens. Ultrasound therapy, with much-encouraging evidence, has been demonstrated to have a beneficial effect on alleviating mental illness symptoms (neuropsychiatric conditions). However, the study of estimating the risk of using transcranial therapeutic ultrasound has barely been investigated. In this experiment, we develop a wearable head-mounted LIPUS device and assessed the possible tissue damage when applying the LIPUS stimulation on the brain. Our computer simulation and in-vitro experiment results demonstrate that the low-intensity ultrasound (LIPUS) device can safely deliver small doses of low-intensity pulsed ultrasound through the skull into the brain without significant thermal injury. The preliminary results indicate that this modality has the potential for the transcranial treatment of neurological diseases in safety.

Curcumin Prevents Brain Damage and Cognitive Dysfunction During Ischemic-reperfusion Through the Regulation of miR-7-5p

OBJECTIVE

This study was to investigate the potential protective effects of curcumin in cerebral ischemia-reperfusion (CIR) and its regulation of miR-7.

METHODS

Rats were occluded by middle cerebral artery occlusion (MCAO) for 1.5 h and reperfused for 2 h to establish a local CIR model. After 24 hours of model establishment, MCAO rats were given curcumin for 3 days by intragastric administration. PC12 cells were cultured for 6 h in oxygen-glucose deprivation medium and then reoxygenated for 24 h to establish an oxygenglucose deprivation/reoxygenation (OGD/R) model. The OGD/R model cells were treated with curcumin for 48 h.

RESULTS

Curcumin inhibited the decrease of miR-7-5p expression and an increase of RelA p65 expression induced by CIR and ODG/R. RelA p65 was a target of miR-7-5p. MiR-7-5p antagonists were able to counteract the effect of curcumin on the expression of RelA p65 in ischemic brain tissue of MCAO rats and OGD/R model cells. Curcumin improved OGD/R-induced inhibition of cell activity, necrosis and apoptosis. Curcumin significantly reduced the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β, reactive oxygen species (ROS) and malondialdehyde (MDA) and increased the activity of superoxide dismutases (SOD) and catalase (CAT) in OGD/R-induced cells. Curcumin may inhibit OGD/R-induced cell damage by regulating miR-7-5p. Curcumin improved cerebral infarction, nerve damage and cognitive dysfunction in rats with CIR, which may be related to the regulation of miR-7-5p/RelA p65 axis.

CONCLUSION

Curcumin exerts cerebral protection by attenuating cell necrosis and apoptosis, inflammatory response and oxidative stress following CIR, which may be related to its regulation of the miR-7/RELA p65 axis.

Rapamycin Pretreatment Alleviates Cerebral Ischemia/Reperfusion Injury in Dose-Response Manner Through Inhibition of the Autophagy and NFκB Pathways in Rats

Although rapamycin can attenuate cerebral ischemia/reperfusion (I/R) injury, the potential roles of rapamycin on cerebral I/R injury remain largely controversial. The present work aims to evaluate underlying molecular mechanisms of rapamycin pretreatment on I/R injury. In total, 34 Sprague-Dawley rats were randomly grouped to 3 groups: sham group (n = 2), vehicle group (n = 16), and rapamycin-pretreatment group (n = 16). Before the focal cerebral ischemia was induced, those rats in the pretreatment group were intraperitoneally injected rapamycin (1 mg/kg body) for 20 hours, while rats in the vehicle group received same-volume saline. Then, rats in these 2 groups received focal cerebral ischemia for 3 and 6 hours, respectively (n = 8 in each group), which was followed by the application of reperfusion for 4, 24, 72 hours, and 1 week (n = 2 in each group). The results showed that the rapamycin pretreatment improved the memory functions of rats after I/R injury, which was evaluated using a Y-maze test. Rapamycin pretreatment significantly reduced the size of triphenyltetrazolium chloride infarction and decreased the expression of I/R injury markers. Moreover, the expression of LC-3 and NFκB was also significantly reduced after rapamycin pretreatment. Taken together, rapamycin pretreatment may alleviate cerebral I/R injury partly through inhibiting autophagic activities and NFκB pathways in rats.

Prevention of acute kidney injury by low intensity pulsed ultrasound via anti-inflammation and anti-apoptosis

The therapeutic effects of low intensity pulsed ultrasound (LIPUS) on renal ischemia/reperfusion injury (IRI) with acute kidney injury (AKI) are still unclear. A renal tubule cell model under H₂O₂ or hypoxia/reoxygenation (H/R) conditions with or without LIPUS pre-treatment (1 MHz, 30 and 100 mW/cm², 15 min) was used to test the in vitro effects of LIPUS. An AKI mouse model of unilateral IRI with nephrectomy of the contralateral kidney for 48 h with or without LIPUS treatment (3 MHz, 100 mW/cm², 20 min/day) 5 day before IRI were used to investigate the in vivo effects of LIPUS. LIPUS significantly protected the renal tubule cell viability and prevented inflammatory signals against H₂O₂ challenge. LIPUS could inhibit the apoptosis-related molecular signals and increase the protein levels of endogenous antioxidant enzymes, α-Klotho, and Sirt1 in renal tubule cells after H/R challenge. LIPUS alleviated the increases in the serum levels of blood urea nitrogen, creatinine, and cystatin C, renal pathological changes and apoptosis-related molecular signals, and impaired antioxidant enzymes in AKI mice. The IRI-induced inflammatory responses in the kidneys and spleens could be reversed by LIPUS. These findings suggest that LIPUS treatment displays the benefits for renal protection in IRI-induced AKI mice.

Treatment with AAV1-Rheb(S16H) provides neuroprotection in a mouse model of photothrombosis-induced ischemic stroke

We recently reported that upregulation of the constitutively active ras homolog enriched in brain [Rheb(S16H)], which induces the activation of the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway, can protect adult neurons, mediated by the induction of neurotrophic factors, such as brain-derived neurotrophic factor (BDNF), in animal models of neurodegenerative diseases. Here we show that neuronal transduction of Rheb(S16H) using adeno-associated virus serotype 1 provides neuroprotection in a mouse model of photothrombosis-induced ischemic stroke. Rheb(S16H)-expressing neurons exhibited neurotrophic effects, such as mTORC1 activation, increases in neuronal size, and BDNF production, in mouse cerebral cortex. Moreover, the upregulation of neuronal Rheb(S16H) significantly attenuated ischemic damage and behavioral impairments as compared to untreated mice, suggesting that Rheb(S16H) upregulation in cortical neurons may be a useful strategy to treat ischemic stroke.

Recent Preclinical Insights Into the Treatment of Chronic Traumatic Encephalopathy

Chronic traumatic encephalopathy (CTE) is a neurodegenerative condition associated with significant mortality and morbidity. The central pathophysiological mechanisms by which repetitive cranial injury results in the neurodegeneration of CTE are poorly understood. Current well-established working models emphasize a central role for trauma-induced excessive phosphorylation and accumulation of insoluble tangles of Tau protein. In this review, we summarize recent data from preclinical animal models of CTE where a series of candidate treatments have been carefully evaluated, including kinase inhibitors, antibody therapy, and anti-inflammatory therapies. We discuss the overall translational potential of these approaches and provide recommendations for future bench-to-bedside treatment strategies.

Neuroprotective effect of low-intensity transcranial ultrasound stimulation in endothelin-1-induced middle cerebral artery occlusion in rats

BACKGROUND

Ischemic stroke is one of the leading causes of death and disability worldwide. Low-intensity transcranial ultrasound stimulation (LITUS) is a promising neuroprotective treatment for ischemic stroke. Diffusion-weighted imaging (DWI) can be highly sensitive in the detection of ischemic brain injury. Relative apparent diffusion coefficient (rADC) values can be used to evaluate the effect of LITUS on ischemic stroke.

PURPOSE

The aim of this study was to determine the neuroprotective effect of LITUS at different time points using endothelin-1-induced middle cerebral artery occlusion in rats as a model of ischemic stroke.

METHODS

Endothelin-1 (ET-1) was injected into the cerebral parenchyma near the middle cerebral artery, which induced focal, reversible, low-flow ischemia in rats. After occlusion of the middle cerebral artery for 30 min, 120 min, and 240 min, LITUS stimulation was used respectively. DWI was performed at 1, 3, 6, 12, 18, 24, 48, and 72 h after ischemia using a 3 T scanner. The rADC values were calculated, and functional outcomes assessed using neurobehavioral scores after ischemia. Nissl staining and estimation of Na⁺-K⁺-ATPase activity were used to assess the neuropathology after completing the last Magnetic Resonance Imaging (MRI) examination.

RESULTS

Endothelin-1-induced occlusion of the middle cerebral artery resulted in significant dysfunction and neuronal damage in rats. Rats that received LITUS exhibited reduced damage of the affected brain tissue after cerebral ischemia. The greatest protective effect was found when LITUS stimulation occurred 30 min after cerebral ischemia.

CONCLUSIONS

Imaging, behavioral, and histological results suggested that LITUS stimulation after an ischemic stroke produced significant neuroprotective effects.

Closed-Loop Transcranial Ultrasound Stimulation for Real-Time Non-invasive Neuromodulation in vivo

The closed-loop brain stimulation technique plays a key role in neural network information processing and therapies of neurological diseases. Transcranial ultrasound stimulation (TUS) is an established neuromodulation method for the neural oscillation in animals or human. All available TUS systems provide brain stimulation in an open-loop pattern. In this study, we developed a closed-loop transcranial ultrasound stimulation (CLTUS) system for real-time non-invasive neuromodulation in vivo. We used the CLTUS system to modulate the neural activities of the hippocampus of a wild-type mouse based on the phase of the theta rhythm recorded at the ultrasound-targeted location. In addition, we modulated the hippocampus of a temporal lobe epilepsy (TLE) mouse. The ultrasound stimulation increased the absolute power and reduced the relative power of the theta rhythm, which were independent of the specific phase of the theta rhythm. Compared with those of a sham stimulation, the latency of epileptic seizures was significantly increased, while the epileptic seizure duration was significantly decreased under the CLTUS. The above results indicate that the CLTUS can be used to not only modulate the neural oscillation through the theta-phase-specific manipulation of the hippocampus but also effectively inhibit the seizure of a TLE mouse in time. CLTUS has large application potentials for the understanding of the causal relationship of neural circuits as well as for timely, effective, and non-invasive therapies of neurological diseases such as epilepsy and Parkinson’s disease.

Icariside II, a PDE5 Inhibitor, Suppresses Oxygen-Glucose Deprivation/Reperfusion-Induced Primary Hippocampal Neuronal Death Through Activating the PKG/CREB/BDNF/TrkB Signaling Pathway

Background

Ischemic stroke remains the leading cause of death and adult disability. Cerebral ischemic/reperfusion (I/R) injury is caused by ischemic stroke thereafter aggravates overwhelming neuronal apoptosis and even the death of neurons. Of note, hippocampus is more susceptive to cerebral I/R injury than the other brain region. This study was designed to explore the effects and mechanism of icariside II (ICS II), a pharmacologically active compound exists in herbal Epimedii with previous study-proved as a phosphodiesterase 5 (PDE5) inhibitor, on the oxygen glucose deprivation/reoxygenation (OGD/R)-induced primary hippocampal neurons injury.

Methods

Effects of ICS II on primary hippocampal neuronal impairment and apoptosis induced by OGD/R were examined by MTT, lactate dehydrogenase (LDH) release, TUNEL staining, and flow cytometry, respectively. Activation of memory-related signaling pathways was measured using Western blot analysis. The direct interaction between ICS II and PDE5 was further evaluated by molecular docking.

Results

ICS II (12.5, 25, 50 μM) markedly abrogated OGD/R-induced hippocampal neuronal death as suggested by the increase in neurons viability and the decrease in cellular LDH release. Furthermore, ICS II not only effectively decreased the protein expression and activity of PDE5, restored the 3′5′-cyclic guanosine monophosphate (cGMP) level and its downstream target protein kinase G (PKG) activity but also increased the phosphorylation of cAMP response element binding protein (CREB) level, expressions of brain derived neurotrophic factor (BDNF), and tyrosine protein kinase B (TrkB). Mechanistically, the inhibitory effects of ICS II were abrogated by Rp-8-Br-cGMP (a PKG inhibitor) or ANA-12 (a TrkB inhibitor), which further confirmed that the favorable effects of ICS II were attributed to its activation of the PKG/CREB/BDNF signaling pathways. Intriguingly, ICS II might effectively bind and inhibited PDE5 activity as demonstrated by relatively high binding scores (−6.52 kcal/mol).

Conclusions

ICS II significantly rescues OGD/R-induced hippocampal neuronal injury. The mechanism is, at least partly, due to inhibition of PDE5 and activation of PKG/CREB/BDNF/TrkB signaling pathway. Hence it is thought that ICS II might be a potential naturally PDE5 inhibitor to combat cerebral I/R injury.

Ultrasound in tumor immunotherapy: Current status and future developments

Immunotherapy has considerable potential in eliminating cancers by activating the host's own immune system, while the thermal and mechanical effects of ultrasound have various applications in tumor therapy. Hyperthermia, ablation, histotripsy, and microbubble stable/inertial cavitation can alter the tumor microenvironment to enhance immunoactivation to inhibit tumor growth. Microbubble cavitation can increase vessel permeability and thereby improve the delivery of immune cells, cytokines, antigens, and antibodies to tumors. Violent microbubble cavitation can disrupt tumor cells and efficiently expose them to numerous antigens so as to promote the maturity of antigen-presenting cells and subsequent adaptive immune-cell activation. This review provides an overview and compares the mechanisms of ultrasound-induced immune modulation for peripheral and brain tumor therapy, even degenerative brain diseases therapy. The possibility of reversing tumors to an immunoactive microenvironment by utilizing the cavitation of microbubbles loaded with therapeutic gases is also proposed as another potential pathway for immunotherapy. Finally, we disuss the challenges and opportunities of ultrasound in immunotherapy for future development.

Neuroprotective Effect of Low-Intensity Transcranial Ultrasound Stimulation in Moderate Traumatic Brain Injury Rats

Traumatic brain injury (TBI) is a kind of severe brain injury characterized with a high incidence rate and a high disability rate. Low-intensity transcranial ultrasound stimulation (LITUS) is a promising neuroprotective method for improving the functional prognosis of TBI. The fractional anisotropy (FA) value and mean diffusivity (MD) value can be sensitive to abnormal brain structure and function and can thus be used to evaluate the effect of LITUS on TBI. Our purpose was to evaluate the therapeutic effect of LITUS in a moderate TBI rat model with FA and MD values. For our method, we used 45 male Sprague Dawley rats (15 sham normal, 15 TBI, and 15 LITUS treatment rats). We used single-shot spin echo echo-planar imaging sequences at 3.0T to obtain the DTI parameters. Parameters of FA and MD on the treated side of the injury cortex were measured to evaluate the therapeutic effect of LITUS in a TBI rat model. For FA and MD values, groups were compared by using a two-way analysis of variance for repeated measures, and this was followed by Tukey's post hoc test. Differences were considered significant at P < 0.05. The results were that the FA value in the LITUS treatment group at 1 day after TBI was significantly higher than that in the control group (adjusted P = 0.0422) and significantly lower than that in the TBI group at 14, 21, and 35 days after TBI (adjusted P = 0.0015, 0.0064, and 0.0173, respectively). At the end of the scan time point, the differences between the two groups were not significant (adjusted P = 0.3242). The MD values in the LITUS treatment group were significantly higher in the early stage than that in the TBI group (adjusted P = 0.0167) and significantly lower at the following time points than in the TBI group. In conclusion, daily treatment with LITUS for 10 min effectively improved the brain damage in the Controlled Cortical Impact (CCI)-caused TBI model. FA and MD values can serve as evaluation indicators for the neuro-protective effect of LITUS.

Therapeutic potential role of exosomes for ischemic stroke

Exosomes are extracellular vesicles with a diameter of 30–100 nm, which are released into the extracellular space by fusion of multivesicular and plasma membranes. These vesicles actually play a distinct role in cell communication, although they were considered as membrane debris in the past. The endosomal sorting complex required for transport (ESCRT)-dependent and ESCRT-independent mechanisms are currently considered to be involved in the sorting of exosomes, and the release of exosomes is related to the members of Rab protein family and SNARE family. In recent years, the therapeutic potential of exosomes has become apparent. For example, via the direct transplantation of exosomes, the ischemic area after stroke is reduced, and the neurological function is improved significantly. Furthermore, they can be used as effective drug delivery vehicles due to their unique characteristics such as low immunogenicity and nanometer size. In conclusion, exosomes provide a cell-free treatment for ischemic stroke.

Transcranial Ultrasound Stimulation Directly Influences the Cortical Excitability of the Motor Cortex in Parkinsonian Mice

BACKGROUND

Low-intensity transcranial ultrasound stimulation is a new noninvasive brain modulation method with high spatial resolution and high penetration depth. However, until now, it was unclear whether transcranial ultrasound stimulation has a significant effect on PD.

OBJECTIVES

In order to evaluate the effect of transcranial ultrasound stimulation on PD.

METHODS

We used transcranial ultrasound stimulation to modulate parkinsonian-related activity in mice administered MPTP and recorded local field potentials in the motor cortex before and after ultrasound stimulation. We analyzed neuronal oscillatory activity known to be relevant to the pathophysiology of PD.

RESULTS

After ultrasound stimulation, mean power intensity in the beta band (13-30 Hz) significantly decreased, and the phase-amplitude coupling strength between the beta and high gamma (55-100 Hz) bands and between the beta and ripple (100-200 Hz) bands also became significantly weaker.

CONCLUSIONS

This study demonstrates that ultrasonic neuromodulation can significantly decrease parkinsonian-related activity in mice administered MPTP. © 2019 International Parkinson and Movement Disorder Society.

The Mechanosensitive Ion Channel Piezo1 Significantly Mediates In Vitro Ultrasonic Stimulation of Neurons

Ultrasound brain stimulation is a promising modality for probing brain function and treating brain disease non-invasively and with high spatiotemporal resolution. However, the mechanism underlying its effects remains unclear. Here, we examine the role that the mouse piezo-type mechanosensitive ion channel component 1 (Piezo1) plays in mediating the in vitro effects of ultrasound in mouse primary cortical neurons and a neuronal cell line. We show that ultrasound alone could activate heterologous and endogenous Piezo1, initiating calcium influx and increased nuclear c-Fos expression in primary neurons but not when pre-treated with a Piezo1 inhibitor. We also found that ultrasound significantly increased the expression of the important proteins phospho-CaMKII, phospho-CREB, and c-Fos in a neuronal cell line, but Piezo1 knockdown significantly reduced this effect. Our findings demonstrate that the activity of mechanosensitive ion channels such as Piezo1 stimulated by ultrasound is an important contributor to its ability to stimulate cells in vitro.

Low Intensity Pulsed Ultrasound Prevents Recurrent Ischemic Stroke in a Cerebral Ischemia/Reperfusion Injury Mouse Model via Brain-derived Neurotrophic Factor Induction

The incidence of stroke recurrence is still higher despite the advanced progression of therapeutic treatment and medical technology. Low intensity pulsed ultrasound (LIPUS) has been demonstrated to possess therapeutic effects on neuronal diseases and stroke via brain-derived neurotrophic factor (BDNF) induction. In this study, we hypothesized that LIPUS treatment possessed therapeutic benefits for the improvement of stroke recurrence. Adult male C57BL/6J mice were subjected to a middle cerebral artery occlusion (MCAO) surgery and then followed to secondary MCAO surgery as a stroke recurrence occurred after nine days from the first MCAO. LIPUS was administered continuously for nine days before secondary MCAO. LIPUS treatment not only decreased the mortality but also significantly moderated neuronal function injury including neurological score, motor activity, and brain pathological score in the recurrent stroke mice. Furthermore, the administration of LIPUS attenuated the apoptotic neuronal cells and increased Bax/Bcl-2 protein expression ratio and accelerated the expression of BDNF in the brain of the recurrent stroke mice. Taken together, these results demonstrate for the first time that LIPUS treatment arouses the expression of BDNF and possesses a therapeutic benefit for the improvement of stroke recurrence in a mouse model. The neuroprotective potential of LIPUS may provide a useful strategy for the prevention of a recurrent stroke.

Preventive potential of low intensity pulsed ultrasound for chronic traumatic encephalopathy after repetitive head collisions in contact sports

Chronic traumatic encephalopathy (CTE), a disease process well-recognized in boxers, American football players and military personnel, is a progressive neurodegenerative disease caused by repetitive blows to the head. Subjects with CTE can have a wide range of emotional, cognitive and physical symptoms. The cognitive group patients had a significantly higher probability of developing dementia in later years. Currently, there are no disease modifying regimen for CTE. Timely intervention of head blow could diminish the development of CTE. Low-intensity pulsed ultrasound (LIPUS) is a common adjunct used to promote bone healing for fresh fracture. Recent reports suggest that LIPUS can noninvasively modulate the cortical function and have neuroprotective effect in various animal models of traumatic brain injury, stroke, Alzheimer's disease and major depressive disorder. The multifunctional mechanisms of LIPUS neuroprotective effect include several trophic factor stimulations, anti-inflammatory properties and reduction of brain edema. From the above evidence, LIPUS intervention could be a strategy for the prevention of the clinical CTE sequelae of repetitive head blows. We hypothesized that due to its neuroprotective effects, the non-invasive and easy-to-use method of LIPUS brain stimulation could have a preventive effect on players who have head blows during the match. The development of a time sensitive protocol, resembling the therapeutic algorithm for traumatic brain injury, would potentially prevent the development of subsequent CTE adverse outcome. Further long-term longitudinal studies of LIPUS stimulation are warranted to verify the prevention efficacy of this intervention for CTE.

Histone deacetylase 6 interference protects mice against experimental stroke-induced brain injury via activating Nrf2/HO-1 pathway

Cerebral stroke is a fatal disease with increasing incidence. The study was to investigate the role and mechanism of Histone deacetylase 6 (HDAC6) on experimental stroke-induced brain injury. The recombinant shRNA-HDAC6 or scramble shRNA lentivirus was transfected to ICR mice. Then, the ischemia/reperfusion injury (I/RI) mice were constructed using middle cerebral artery occlusion (MCAO) method. Brain TTC staining was used to determine infarct areas. Serum levels of oxidative stress-related factors were detected by enzyme linked immunosorbnent assay (ELISA). Realtime-qPCR (RT-qPCR) and Western blot were used to respectively detect mRNA and protein levels. HDAC6 was up-regulated in brain I/RI mice (MCAO group), and down-regulated again in MCAO mice transfected with shRNA-HDAC6 (MCAO + shRNA group). The infarct area of the MCAO mice was increased, neurological scores were higher, and serum protein levels of 3-NT, 4-HNE and 8-OHdG were higher. HDAC6 interference attenuated above effects. Though protein levels of Nrf2 and HO-1 in cytoplasm increased slightly in MCAO group, they increased significantly by HDAC6 interference. The protein levels of Nrf2 in cytoblast decreased significantly in MCAO group, and increased markedly by HDAC6 interference. HDAC6 interference protected mice against experimental stroke-induced brain injury via Nrf2/HO-1 pathway.

The Role of Astragaloside IV against Cerebral Ischemia/Reperfusion Injury: Suppression of Apoptosis via Promotion of P62-LC3-Autophagy

Background: Ischemia/reperfusion (I/R) caused by ischemic stroke treatments leads to brain injury, and autophagy plays a role in the pathology. Astragaloside IV is a potential neuroprotectant, but its underlying mechanism on cerebral I/R injury needs to be explored. The objective of this study is to investigate the neuroprotective mechanism of Astragaloside IV against cerebral I/R injury. Methods: Middle cerebral artery occlusion method (MCAO) and oxygen and glucose deprivation/reoxygenation (OGD/R) method were used to simulate cerebral I/R injury in Sprague-Dawley (SD) rats and HT22 cells, respectively. The neurological score, 2,3,5-Triphe-nyltetrazolium chloride (TTC) staining, and transmission electron microscope were used to detect cerebral damage in SD rats. Cell viability and cytotoxicity assay were tested in vitro. Fluorescent staining and flow cytometry were applied to detect the level of apoptosis. Western blotting was conducted to examine the expression of proteins associated with autophagy. Results: This study found that Astragaloside IV could decrease the neurological score, reduce the infarct volume in the brain, and alleviate cerebral I/R injury in MCAO rats. Astragaloside IV promoted cell viability and balanced Bcl-2 and Bax expression in vitro, reduced the rate of apoptosis, decreased the expression of P62, and increased the expression of LC3II/LC3I in HT22 cells after OGD/R. Conclusions: These data suggested that Astragaloside IV plays a neuroprotective role by down-regulating apoptosis by promoting the degree of autophagy.

Protective effect of low-intensity transcranial ultrasound stimulation after differing delay following an acute ischemic stroke

BACKGROUND

Ischemic stroke is a clinically common disease requiring early treatment in the acute period of stroke onset. Such early treatment reduces the level of brain injury, promotes functional recovery, and improves long-term prognosis. Previous studies have demonstrated that, in the event of an acute ischemic stroke, low-intensity transcranial ultrasound stimulation (LITUS) can provide neuroprotection. However, from existing studies, the protective effect of LITUS with differing delay after an acute ischemic stroke remains unclear.

OBJECTIVE

The aim of the present study is to investigate whether the protective effect of LITUS in the event of an acute ischemic stroke differs with the time delay between the stroke and the application of LITUS.

METHODS

In the present study, 60 Sprague Dawley rats (250 ± 10 g) were divided randomly into five groups (each group including LITUS group (6 rats) and control group (CTRL group: 6 rats)) with different treatment delays (0.5 h, 1 h, 3 h, 6 h, and 9 h). The rats were made to have an ischemic stroke by means of a distal middle cerebral artery occlusion. Next, magnetic response (MR) imaging was performed 15 min before LITUS in each group (marked as Pre-Stim). Once the MR imaging was finished, the rats were stimulated with ultrasound for 10 min (I_sppa = 2.6 W/cm², fundamental frequency: 500 kHz, duty cycle: 50%, stimulation duration: 400 ms) in the LITUS groups and went without ultrasound stimulation in the control (CTRL) group. Then, MR imaging was performed once every hour for three hours after LITUS (marked as Post-Stim (1 h), Post-Stim (2 h), and Post-Stim (3 h)). Finally, triphenyltetrazolium chloride staining of the rat brain tissues was performed. We analyzed the apparent diffusion coefficient (ADC) of the lesion area in Pre-Stim and Post-Stim and evaluated the differences between the LITUS groups and the CTRL group for the different treatment delays (0.5 h, 1 h, 3 h, 6 h, and 9 h).

RESULTS

Compared to the CTRL group, LITUS significantly inhibited the ADC decrease (i) at the Post-Stim (1 h), Post-Stim (2 h), and Post-Stim (3 h) stages when the rats were stimulated at 0.5 h, (ii) at Post-Stim (1 h) and Post-Stim (2 h) when the rats were stimulated at 1 h and 3 h, and (iii) at Post-Stim (1 h) when the rats were stimulated at 6 h. There was no significant change in the ADC at Post-Stim (1 h), Post-Stim (2 h), and Post-Stim (3 h) when the rats were stimulated at 9 h.

CONCLUSION

In the event of an acute ischemic stroke, LITUS can inhibit the decrease of ADC and the effect is closely related to the delay in treatment. The earlier the ultrasound intervention, the better the protective effect.

The effect of anesthetic dose on the motor response induced by low-intensity pulsed ultrasound stimulation

Background

Low-intensity pulsed ultrasound stimulation (LIPUS) has been proven to be a noninvasive method with high spatial resolution and deep penetration. Previous studies have qualitatively demonstrated that the electromyographic response caused by LIPUS in the mouse motor cortex is affected by the anesthetic state of the mice. However, the quantitative relationship between motor response and anesthetic dose remains unclear.

Results

Experimental results show that the success rate decreases stepwise as the isoflurane concentration/mouse weight ratio increases (ratios: [0.004%/g, 0.01%/g], success rate: ~ 90%; [0.012%/g, 0.014%/g], ~ 40%; [0.016%/g, 0.018%/g], ~ 7%; 0.024%/g, 0). The latency and duration of EMG increase significantly when the ratio is more than 0.016%/g. Compared with that at ratios from 0.004 to 0.016%/g, normalized EMG amplitude decreases significantly at ratios of 0.018%/g and 0.020%/g.

Conclusions

Quantitative calculations indicate that the anesthetic dose has a significant regulatory effect on the motor response of mice during LIPUS. Our results have guiding significance for the selection of the anesthetic dose for LIPUS in mouse motor cortex experiments.