Transcranial low-intensity ultrasound stimulation for treating central nervous system disorders: A promising therapeutic application

Integrating data mining with transcranial focused ultrasound to refine neuralgia treatment strategies

BACKGROUND

Neuralgia and other neuropathic pain are difficult to treat owing to their complicated etiology and a wide variety of responses to treatment. The novel neuromodulation technology transcranial focused ultrasound (tFUS) has intriguing implications in targeted non-invasive brain stimulation. Patient-specific variables and neurological processes must be better understood to enhance tFUS for personalized therapy.

METHODS

In this research, a Machine Learning based Transcranial Focused Ultrasound Personalized Model (ML-tFUSPM) has been proposed to treat neuralgia by combining tFUS with data mining for personalized therapy. Data mining algorithms can examine patient demographics, pain factors, imaging data, and therapy outcomes to uncover response patterns and treatment predictors. According to these results, tFUS may be tailored to each patient by targeting brain regions involved in pain perception and control.

RESULTS

Initial studies show that data-driven models and tFUS enhance therapeutic efficacy, side effects, and accuracy. This collaborative endeavor uses data analytics and neuromodulation to customize neuralgia treatment. The new model's emphasis on targeted treatments and predictive analytics gives clinicians evidence-based tools to manage pain more effectively and personally, which might transform the industry.

COMPARATIVE ANALYSIS

The experimental results show that the proposed method has a high accuracy ratio of 97 % compared to other methods.

CONCLUSION

According to this study, computational principles and cutting-edge technology may lead to game-changing neurology and pain management advances.

Transcriptomic Alterations in the Hippocampus and Prefrontal Cortex of Rats with Chronic Unpredictable Stress Induced by Low-Intensity Pulsed Ultrasound

In our previous study, low-intensity pulsed ultrasound stimulation (LIPUS), a novel noninvasive neuromodulation tool, effectively alleviated depression-like behaviors in a rat model of depression. However, the underlying mechanisms remain unclear. The present study aimed to elucidate the relevant mechanisms through transcriptomic research. To induce depression-like phenotypes, rats were subjected to chronic unpredictable stress (CUS) for six weeks. Following this initial stress period, LIPUS was administered daily for an additional four weeks while the rats were continuously exposed to CUS, which was previously determined to significantly reduce immobility time in forced swimming test. The transcriptome expression profiles in the hippocampus and prefrontal cortex (PFC) were subsequently analyzed by RNA sequencing techniques. Overall, LIPUS reversed the abnormal expression of genes in the brain of model rats, especially the expression of genes linked to glucose and lipid metabolism. Specifically, we found that the CUS rats exhibited 3464 differentially expressed genes (DEGs) in the hippocampus and 1781 DEGs in the PFC compared to the control group. LIPUS reversed the expression of 592 genes in the hippocampus and 254 genes in the PFC. Functional analysis revealed a significant enrichment of DEGs related to oxygen carrier activity and sugar metabolism. Subsequently, the alterations in the top ten genes were validated using real-time PCR. The significant changes in the expression of hemoglobin subunit beta, growth hormone 1, and glucokinase were confirmed. The results suggest that LIPUS may alleviate depression-related manifestations by regulating cerebral oxygenation and sugar metabolism processes in the brain.

Low-intensity Pulsed Ultrasound Stimulation of the Intestine Improves Insulin Resistance in Type 2 Diabetes

OBJECTIVE

Ultrasound stimulation of internal organs and peripheral nerves has demonstrated promising potential in regulating blood glucose metabolism. This study aims to assess the effectiveness of low-intensity pulsed ultrasound stimulation (LIPUS) on intestine in improving insulin resistance with type 2 diabetes mellitus (T2DM).

METHODS

C57BL/6J mice, both normal and T2DM, were randomly divided into three groups: Control, T2D-sham, and T2D-LIPUS. The T2D-LIPUS group received LIPUS stimulation in the intestine. The parameters were as follows: 1 MHz frequency, 1.0 kHz pulse repetition frequency (PRF), 20% duty cycle, 100 mW/cm² intensity spatial average temporal average (ISATA), for 20 minutes per session, five days per week, over four weeks.

RESULTS

Blood glucose analysis indicated that mice in the T2D-LIPUS group displayed significantly lower area under the curve (AUC) of glucose tolerance tests (GTT) and insulin tolerance tests (ITT) (p < 0.001), HOMA-IR (p < 0.001), and fasting serum insulin levels (p < 0.01) compared to the T2D-sham group. LIPUS treatment effectively lowered serum levels of IL-1β (p < 0.001) and TNF-α (p < 0.01) along with mRNA expression levels of IL-1β (p < 0.01) and IL-18 (p < 0.001) in the intestines of T2DM mice. Additionally, Western blot analysis revealed a reduction in the protein levels of NLRP3, caspase-1, and GSDMD-N in the intestinal tissues of mice treated with LIPUS.

CONCLUSION

These findings suggest that LIPUS can reduce inflammation and cellular apoptosis, while improving insulin resistance by inhibiting the NLRP3/Caspase-1/GSDMD signaling pathway. This research introduces a novel, non-pharmacological approach for managing T2DM.

Theta-gamma phase-amplitude coupling as a promising neurophysiological biomarker for evaluating the efficacy of low-intensity focused ultrasound stimulation on vascular dementia treatment

Low-intensity focused ultrasound stimulation (LIFUS) has garnered attention for its potential in vascular dementia (VD) treatment. However, the lack of sufficient data supporting its efficacy and elucidating its mechanisms of action limits its further clinical translation and application. Considerable researches support the idea that LIFUS can improve the disturbance of neural oscillation modes caused by a variety of neurological diseases. However, the effect of LIFUS on neural oscillation modes in VD remains unclear. Therefore, this study aims to investigate the therapeutic effects of LIFUS on neural oscillation modes in VD. To achieve this purpose, the VD model was established via the bilateral common carotid artery occlusion, followed by two weeks of LIFUS treatment targeting the bilateral hippocampus. The therapeutic effects of LIFUS were evaluated by behavioral tests and cerebral blood flow measurement. Electrophysiological signals were recorded from the hippocampal CA1 and CA3 and medial prefrontal cortex (mPFC). The results indicated LIFUS could effectively improve cognitive dysfunction in VD rats. The underlying electrophysiological mechanisms involved the restoration of phase-amplitude coupling (PAC) of theta-gamma oscillations within both the CA3-CA1 local circuit and the hippocampus-mPFC cross-brain circuit. Classification results based on PAC characteristics suggested that PAC metrics are effective for evaluating the efficacy of LIFUS in treating VD, with optimal recognition performance observed in the hippocampus-mPFC cross-brain circuit. Our findings provide neuroelectrophysiological insights into the mechanisms of LIFUS in VD treatment and propose a promising diagnostic biomarker for evaluating LIFUS efficacy in future applications.

Advancements in ultrasound-mediated drug delivery for central nervous system disorders

INTRODUCTION

Central nervous system (CNS) disorders present major therapeutic challenges due to the presence of the blood - brain barrier (BBB) and disease heterogeneity. The BBB impedes most therapeutic agents, which restricts conventional treatments. Focused ultrasound (FUS) -assisted delivery offers a novel solution by temporarily disrupting the BBB and thereby enhancing drug delivery to the CNS.

AREAS COVERED

This review outlines the fundamental principles of FUS-assisted drug delivery technology, with an emphasis on its role in enhancing the spatial precision of therapeutic interventions and its molecular effects on the cellular composition of the BBB. Recent promising clinical studies are surveyed, and a comparative analysis of current US-assisted delivery system is provided. Additionally, the latest advancements and challenges of this technology are discussed.

EXPERT OPINION

FUS-mediated drug delivery shows promise, but the clinical translation of research findings is challenging. Key issues include safety, dosage optimization, and balancing efficacy with the risk of tissue damage. Continued research is crucial to address these challenges and bridge the gap between preclinical and clinical applications, and could transform treatments of CNS disorders.

Neuromodulation Strategies in Lifelong Bipolar Disorder: A Narrative Review

Bipolar disorder is a debilitating psychiatric condition characterized by recurrent episodes of mania and depression, affecting millions worldwide. While pharmacotherapy remains the cornerstone of treatment, a significant proportion of patients exhibit inadequate response or intolerable side effects to conventional medications. In recent years, neuromodulation techniques have emerged as promising adjunctive or alternative treatments for bipolar disorder. We performed a narrative review, according to the Scale for the Assessment of Narrative Review Articles (SANRA) guidelines, to provide a comprehensive overview of the current literature on neuromodulation interventions in bipolar disorder across the course of lifespan. Specifically, it examines the efficacy, safety, and mechanisms of action of various neuromodulation strategies, including, among others, transcranial magnetic stimulation (TMS), electroconvulsive therapy (ECT), vagus nerve stimulation (VNS), deep brain stimulation (DBS), and it describes the therapeutic experiences across the different ages of illness. Additionally, this review discusses the clinical implications, challenges, and future directions of the integration, in clinical practice, of neuromodulation into the management of bipolar disorder. By synthesizing evidence from different studies, this review aims to inform clinicians, researchers, and stakeholders about the evolving landscape of neuromodulation treatments and their potential role in improving outcomes for individuals with bipolar disorder.

Clinical efficacy of low-intensity pulsed ultrasound in Parkinson's disease with cognitive impairment

Low-intensity pulsed ultrasound (LIPUS) is a new technique for invasive brain stimulation and modulation that has emerged recently, but the effects in Parkinson's disease with cognitive impairment (PD-CI) have been less observed. In this study, we recruited 56 patients with PD-CI who were continuously treated with LIPUS for 8 wk, and observed the clinical efficacy of LIPUS on patients with PD-CI by comparing with the Sham stimulation continuous treatment. Fifty-six patients with PD-CI were divided into the Sham group (given Sham stimulation on top of conventional medication, n = 28) and the LIPUS group (given LIPUS stimulation on top of conventional medication, n = 28), and both groups continued treatment for 8 wk. Post-treatment efficacy and pre- and post-treatment cognitive function [Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA)], emotional state [Beck Anxiety Inventory (BAI), Beck Depression Inventory (BDI)], quality of life [Unified Parkinson's Disease Rating Scale (UPDRS), 39-item Parkinson's Disease Questionnaire (PDQ-39)], and serologic indices [5-hydroxytryptamine (5-HT), norepinephrine (NE), and dopamine (DA)] were compared. The total effective rate of the LIPUS group was higher versus that of the Sham group. In both groups, MMSE and MoCA scores increased; BDI and BAI scores decreased; UPDRS and PDQ-39 scores were reduced; the levels of 5-HT, NE, and DA were elevated. The aforementioned changes were more pronounced in the LIPUS group (all P < 0.05). The application of LIPUS on PD-CI could ameliorate patients' cognitive function, emotional state, and quality of life, and regulate and optimize neurotransmitter expression levels.NEW & NOTEWORTHY This paper provides some data to inform the potential of LIPUS in the treatment of PD-CI.

Long-term transcranial ultrasound stimulation regulates neuroinflammation to ameliorate post-myocardial infarction cardiac arrhythmia and remodeling

BACKGROUND

Sympathetic overactivation and neuroinflammation in the paraventricular nucleus (PVN) are crucial factors in post-myocardial infarction (MI) cardiac remodeling and ventricular arrhythmias (VAs). Prior study has indicated that low-intensity focused ultrasound stimulation could attenuate sympathetic neuroinflammation within the PVN to prevent the occurrence of VAs in an acute MI model. Meanwhile, the cGAS-STING pathway has shown potential to ameliorate the neuroinflammatory response. However, the effect and mechanisms of long-term transcranial ultrasound stimulation (LTUS) for modulating neuroinflammation in the chronic stage of MI remain unclear.

OBJECTIVE

This study aimed to ascertain whether LTUS could mitigate post-MI neuroinflammation and improve cardiac arrhythmia and remodeling through the cGAS-STING pathway.

METHODS

Thirty-six SD rats were equally randomized to the sham group (pseudo-MI modeling), chronic MI group (MI modeling), and LTUS group (MI modeling and long-term ultrasound stimulation). Transcranial ultrasound stimulation (15 min/d) was conducted on the PVN for 4 consecutive weeks. After 4-week intervention, echocardiography, electrophysiologic experiments, and histopathologic staining were performed to assess the role of LTUS on post-MI neuroinflammation and cardiac remodeling.

RESULTS

The results indicated that LTUS significantly facilitated microglial M1 to M2 polarization through the cGAS-STING signaling pathway within the PVN. Furthermore, LTUS inhibited MI-induced sympathetic neuroinflammation, thereby improving cardiac dysfunction, ameliorating cardiac remodeling, and reducing VA inducibility.

CONCLUSION

Long-term ultrasound stimulation of the PVN was found to alleviate post-MI neuroinflammation and to improve cardiac remodeling, which might inspire novel insights and clinical strategies for noninvasive neuromodulation and the treatment of post-MI VAs.

Targeted sonogenetic modulation of GABAergic interneurons in the hippocampal CA1 region in status epilepticus

Rationale: Sonogenetics is an advanced ultrasound-based neurostimulation approach for targeting neurons in specific brain regions. However, the role of sonogenetics in treating status epilepticus (SE) remains unclear. Here, we aimed to investigate the effects of ultrasound neurostimulation and MscL-G22S (a mechanosensitive ion channel that mediates Ca2+ influx)-mediated sonogenetics (MG-SOG) in a mouse model of kainic acid (KA)-induced SE. Methods: For MG-SOG, a Cre-dependent AAV expressing MscL-G22S was injected into parvalbumin (PV)-cre and somatostatin (SST)-cre mice to induce the expression of MscL-G22S-EGFP in PV interneurons (PV-INs) and SST interneurons (SST-INs), respectively; mice were stimulated with continuous pulses of ultrasound stimulation during the latency of generalized seizures (GSs), the latency to SE, in SE model mice. We performed calcium fiber photometry, patch-clamp recording, local field potential recording, and SE monitoring to investigate the role of MG-SOG in treating SE. Results: First, we observed obvious neuronal activation in the hippocampal CA1 region in SE model mice. Both excitatory neurons (ENs) and GABAergic interneurons (GABA-INs) in the CA1 region were activated in SE model mice; however, the inhibitory effect of GABA-INs on ENs seemed to be insufficient to reduce EN excitability despite the increased activation of GABA-INs in SE model mice. Thus, we speculated that MG-SOG-induced activation of GABA-INs, mainly SST-INs and PV-INs, in the CA1 region may protect against SE. We found that MG-SOG-mediated PV-IN activation in the CA1 region ameliorated SE and changed SE-related electrophysiological abnormalities in the CA1 region; however, MG-SOG-induced SST-IN activation in the CA1 region did not ameliorate SE. Conclusions: MG-SOG-mediated activation of PV-INs had a positive effect on relieving SE. Our work may promote the development of sonogenetic neurostimulation techniques for treating SE.

Ultrasound pulse repetition frequency preferentially activates different neuron populations independent of cell type

Objective. Transcranial ultrasound (US) stimulation serves as an external input to a neuron, and thus the evoked response relies on neurons' intrinsic properties. Neural activity is limited to a couple hundred hertz and often exhibits preference to input frequencies. Accordingly, US pulsed at specific physiologic pulse repetition frequencies (PRFs) may selectively engage neurons with the corresponding input frequency preference. However, most US parametric studies examine the effects of supraphysiologic PRFs. It remains unclear whether pulsing US at different physiologic PRFs could activate distinct neurons in the awake mammalian brain.Approach. We recorded cellular calcium responses of individual motor cortex neurons to US pulsed at PRFs of 10, 40, and 140 Hz in awake mice. We compared the evoked responses across these PRFs in the same neurons. To further understand the cell-type dependent effects, we categorized the recorded neurons as parvalbumin positive fast spiking interneurons or putative excitatory neurons and analyzed single-cell mechanosensitive channel expression in mice and humans using the Allen Brain Institute's RNA-sequencing databases.Main results. We discovered that many neurons were preferentially activated by only one PRF and different PRFs selectively engaged distinct neuronal populations. US-evoked cellular calcium responses exhibited the same characteristics as those naturally occurring during spiking, suggesting that US increases intrinsic neuronal activity. Furthermore, evoked responses were similar between fast-spiking inhibitory neurons and putative excitatory neurons. Thus, variation in individual neuron's cellular properties dominates US-evoked response heterogeneity, consistent with our observed cell-type independent expression patterns of mechanosensitive channels across individual neurons in mice and humans. Finally, US transiently increased network synchrony without producing prolonged over-synchronization that could be detrimental to neural circuit functions.Significance. These results highlight the feasibility of activating distinct neuronal subgroups by varying PRF and the potential to improve neuromodulation effects by combining physiologic PRFs.

Low intensity focused ultrasound stimulation targeted on M1 ameliorates neuroinflammation in hemi-parkinsonian rats

OBJECTIVE

Low intensity focused stimulation (LIFUS) has been proved to improve motor function in Parkinson's disease (PD) animal modules. The aim of this study is to investigate whether LIFUS target on the primary motor cortex (M1) can improve motor deficit in the PD rats.

METHODS

The PD rat model was induced by injection of 6-hydroxydopamine (6-OHDA) in the medial forebrain bundle (MFB). Two weeks after the injection, LIFUS was used on PD rats for two weeks. Behavioral tests were performed including open field test and rotarod test to examine the motor ability of the rats. The activity of microglia and astrocyte were tested to evaluate the inflammation level in the brain. The tyrosine hydroxylase (TH) staining was done to detect the recovery of dopaminergic (DA) neurons in the substantia nigra (SN) and DA fibers in the striatum (STR).

RESULTS

LIFUS treatment decreased the resting time in OFT(p<0.05) and increased the latency to falls in the rotarod test(p<0.05) compared with the untreated PD rats. Moreover, LIFUS reduced the inflammation response reflected in microglia and astrocyte activation. Additionally, TH-immunoreactive fibers increased in the STR after LIFUS.

CONCLUSION

These findings demonstrated that LIPUS targeted on M1 can inhibit neuroinflammation and improve movement disorders of PD rats.

SIGNIFICANCE

This study provides a new therapeutic strategy for further clinical application in PD.

MR-guided focused ultrasound in movement disorders and beyond: Lessons learned and new frontiers

The development of MR-guided focused ultrasound (MRgFUS) has provided a new therapeutic tool for neuropsychiatric disorders. In contrast to previously available neurosurgical techniques, MRgFUS allows precise impact on deep brain structures without the need for incision and yields an immediate effect. In its high-intensity modality (MRgHIFU), it produces accurate therapeutic thermoablation in previously selected brain targets. Importantly, the production of the lesion is progressive and highly controlled in real-time by both neuroimaging and clinical means. MRgHIFU ablation is already an accepted and widely used treatment for medically-refractory Parkinson's disease and essential tremor. Notably, other neurological disorders and diverse brain targets, including bilateral treatments, are currently under examination. Conversely, the low-intensity modality (MRgLIFU) shows promising prospects in neuromodulation and transient blood-brain barrier opening (BBBO). In the former circumstance, MRgLIFU could serve as a powerful clinical and research tool for non-invasively modulating brain activity and function. BBBO, on the other hand, emerges as a potentially impactful method to influence disease pathogenesis and progression by increasing brain target engagement of putative therapeutic agents. While promising, these applications remain experimental. As a recently developed technology, MRgFUS is not without challenges and questions to be addressed. Further developments and broader experience are necessary to enhance MRgFUS capabilities in both research and clinical practice, as well as to define device constraints. This clinical mini-review aims to provide an overview of the main evidence of MRgFUS application and to highlight unmet needs and future potentialities of the technique.

Ultrasound pulse repetition frequency preferentially activates different neuron populations independent of cell type

Transcranial ultrasound activates mechanosensitive cellular signaling and modulates neural dynamics. Given that intrinsic neuronal activity is limited to a couple hundred hertz and often exhibits frequency preference, we examined whether pulsing ultrasound at physiologic pulse repetition frequencies (PRFs) could selectively influence neuronal activity in the mammalian brain. We performed calcium imaging of individual motor cortex neurons, while delivering 0.35 MHz ultrasound at PRFs of 10, 40, and 140 Hz in awake mice. We found that most neurons were preferentially activated by only one of the three PRFs, highlighting unique cellular effects of physiologic PRFs. Further, ultrasound evoked responses were similar between excitatory neurons and parvalbumin positive interneurons regardless of PRFs, indicating that individual cell sensitivity dominates ultrasound-evoked effects, consistent with the heterogeneous mechanosensitive channel expression we found across single neurons in mice and humans. These results highlight the feasibility of tuning ultrasound neuromodulation effects through varying PRFs.

The effect of transcranial ultrasound pulse repetition frequency on sustained inhibition in the human primary motor cortex: A double-blind, sham-controlled study

BACKGROUND

Non-invasive brain stimulation techniques such as transcranial magnetic stimulation and transcranial direct current stimulation hold promise for inducing brain plasticity. However, their limited precision may hamper certain applications. In contrast, Transcranial Ultrasound Stimulation (TUS), known for its precision and deep brain targeting capabilities, requires further investigation to establish its efficacy in producing enduring effects for treating neurological and psychiatric disorders.

OBJECTIVE

To investigate the enduring effects of different pulse repetition frequencies (PRF) of TUS on motor corticospinal excitability.

METHODS

T1-, T2-weighted, and zero echo time magnetic resonance imaging scans were acquired from 21 neurologically healthy participants for neuronavigation, skull reconstruction, and the performance of transcranial ultrasound and thermal modelling. The effects of three different TUS PRFs (10, 100, and 1000 Hz) with a constant duty cycle of 10 % on corticospinal excitability in the primary motor cortex were assessed using TMS-induced motor evoked potentials (MEPs). Each PRF and sham condition was evaluated on separate days, with measurements taken 5-, 30-, and 60-min post-TUS.

RESULTS

A significant decrease in MEP amplitude was observed with a PRF of 10 Hz (p = 0.007), which persisted for at least 30 min, and with a PRF of 100 Hz (p = 0.001), lasting over 60 min. However, no significant changes were found for the PRF of 1000 Hz and the sham conditions.

CONCLUSION

This study highlights the significance of PRF selection in TUS and underscores its potential as a non-invasive approach to reduce corticospinal excitability, offering valuable insights for future clinical applications.

Liability, risks, and recommendations for ultrasound use in the diagnosis of obstetrics diseases

This literature review will summarize the liability issues, risks, and ultrasound recommendations for diagnosing obstetrics diseases. One liability issue is related to misdiagnosis or failure to detect abnormalities during an ultrasound examination. Ultrasound images can be subjective interpretations, and errors may occur due to factors such as operator skill, equipment limitations, or fetal positioning. Another liability concern is related to the potential adverse effects of ultrasound exposure on both the mother and fetus. While extensive research has shown that diagnostic ultrasound is generally safe when used appropriately, there are still uncertainties regarding long-term effects. Some studies suggest a possible association between prolonged or excessive exposure to ultrasound waves and adverse outcomes such as low birth weight, developmental delays, or hearing impairment. Additionally, obtaining informed consent from patients is crucial in mitigating liability risks. Patients should be informed about the purpose of the ultrasound examination, its benefits, limitations, potential risks (even if minimal), and any alternative diagnostic options available. This ensures that patients know the procedure and can make informed decisions about their healthcare. Proper documentation helps establish a clear record of the care provided and can serve as evidence in any legal disputes.

Current emerging novel therapies for Alzheimer's disease and the future prospects of magneto-mechanical force therapy

Alzheimer's disease (AD) is the most common neurodegenerative disease among the elderly, and the morbidity increases with the aging population aggravation. The clinical symptoms of AD mainly include cognitive impairment and memory loss, which undoubtedly bring a huge burden to families and society. Currently, the drugs in clinical use only improve the symptoms of AD but do not cure or prevent the progression of the disease. Therefore, it is urgent for us to develop novel therapeutic strategies for effective AD treatment. To provide a better theoretical basis for exploring novel therapeutic strategies in future AD treatment, this review introduces the recent AD treatment technologies from three aspects, including nanoparticle (NP) based drug therapy, biological therapy and physical therapy. The nanoparticle-mediated therapeutic approaches at the nanomaterial-neural interface and biological system are described in detail, and in particular the magneto-regulated strategies by magnetic field actuating magnetic nanoparticles are highlighted. Promising application of magneto-mechanical force regulated strategy in future AD treatment is also addressed, which offer possibilities for the remote manipulation in a precise manner. In the future, it may be possible for physicians to realize a remote, precise and effective therapy for AD using magneto-mechanical force regulated technology based on the combination of magnetic nanoparticles and an external magnetic field.