Stimulation of the hepatoportal nerve plexus with focused ultrasound restores glucose homoeostasis in diabetic mice, rats and swine

Inhibiting Effect of LIPUS on Epithelial-Mesenchymal Transition in Lens Epithelial Cells

To investigate the effect of low-intensity pulsed ultrasound (LIPUS) on epithelial-mesenchymal transition (EMT) in lens epithelial cells. EMT was induced using high glucose (HG) in SRA01/04 cells. Optimal parameters for LIPUS irradiation were determined by cell counting kit-8 assays and flow cytometry. Cell morphology was assessed by light microscopy, while cell migration ability was analyzed by a wound healing assay. Levels of specific proteins and the relationship between autophagy and the cytoskeleton were examined by immunofluorescence (IF) staining and Western blot (WB). Cytoskeletal structures were visualized by phalloidin staining and autophagosomes were quantified by transmission electron microscopy. EMT was successfully induced by HG treatment. Compared to the model group, LIPUS irradiation resulted in a change in cell morphology from spindle to oval, a significant decrease in cell migration area, and an increase in E-cadherin and LC3B/LC3A levels. In contrast, α-SMA and SQSTM1/P62 levels decreased, the number of autophagosomes increased and F-actin levels decreased in the LIPUS group. SRA01/04 cells treated with LIPUS irradiation after autophagy inhibitors 3-MA and CQ showed increased cell migration area compared to the 3-MA/CQ group; LC3B/LC3A levels decreased; SQSTM1/P62 and F-actin levels increased in the LIPUS + 3-MA/CQ group compared to 3-MA/CQ treatment alone. Colocalization of the cytoskeletal marker Arpc2 with the autophagy marker SQSTM1/P62 was also observed. After treatment with the cytoskeletal inhibitor CK666+LIPUS combination therapy, SQSTM1/P62 levels increased while LC3B/LC3A levels decreased. LIPUS inhibited HG-induced EMT by restoring autophagy, which appears to be associated with cytoskeletal remodeling.

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.

Recent advances in targeting obesity, with a focus on TGF-β signaling and vagus nerve innervation

Over a third of the global population is affected by obesity, fatty liver disease (Metabolic Dysfunction-Associated Steatotic Liver Disease, MASLD), and its severe form, MASH (Metabolic Dysfunction-Associated Steatohepatitis), which can ultimately progress to hepatocellular carcinoma (HCC). Recent advancements include therapeutics such as glucagon-like peptide 1 (GLP-1) agonists and neural/vagal modulation strategies for these disorders. Among the many pathways regulating these conditions, emerging insights into transforming growth factor-β (TGF-β) signaling highlight potential future targets through its role in pathophysiological processes such as adipogenesis, inflammation, and fibrosis. Vagus nerve innervation in the gastrointestinal tract is involved in satiety regulation and energy homeostasis, and vagus nerve stimulation has been applied in weight loss and diabetes. This review explores clinical trials in obesity, novel therapeutic targets, and the role of TGF-β signaling and vagus nerve modulation in obesity-related liver diseases and HCC.

Liver Neurobiology: Regulation of Liver Functions by the Nervous System

The nervous system plays an important role in the regulation of liver functions during physiological as well as pathological conditions. This regulatory effect is based on the processing of signals transmitted to the brain by sensory nerves innervating the liver tissue and other visceral organs and by humoral pathways transmitting signals from peripheral tissues and organs. Based on these signals, the brain modulates metabolism, detoxification, regeneration, repair, inflammation, and other processes occurring in the liver. The nervous system thus determines the functional and morphological characteristics of the liver. Liver innervation also mediates the influence of psychosocial factors on liver functions. The aim of this review is to describe complexity of bidirectional interactions between the brain and liver and to characterize the mechanisms and pathways through which the nervous system influences liver function during physiological conditions and maintains liver and systemic homeostasis.

Low intensity trans-spinal focused ultrasound reduces mechanical sensitivity and suppresses spinal microglia activation in rats with chronic constriction injury

Low intensity, trans-spinal focused ultrasound (tsFUS) is a noninvasive neuromodulation approach that has been shown to modulate spinal circuit excitability in healthy rats. Here, we evaluated the potential of tsFUS for alleviating neuropathic pain by testing it in a chronic constriction injury (CCI) model. Male rats underwent CCI of the left sciatic nerve and then received tsFUS (2 kHz pulse repetition frequency; 40% duty cycle) or sham stimulation, targeted at spinal segment level L5 for 3 min daily over three days. As expected, CCI causes significant reduction of von Frey Threshold (vFT), a measure of mechanical sensitivity. We found that tsFUS treatment is associated with increased vFT compared to sham; this increase persists beyond the duration of treatment, through days 4 to 23 post-CCI. In spinal cords of tsFUS-treated animals, counts of spinal microglia (Iba1 + cells) and of activated, pro-inflammatory microglia (Iba1 + /CD86 + cells), are reduced compared to sham-treated animals. This reduction in microglia counts is limited to the insonified side of the spinal cord, ipsilateral to CCI. These findings suggest that tsFUS may be a promising approach for treatment of neuropathic pain at early stages, possibly by attenuating the development of microglial-driven inflammation.

Subcellular Cavitation Bubbles Induce Cellular Mechanolysis and Collective Wound Healing in Ultrasound-Inflicted Cell Ablation

Focused ultrasound (FUS) has been widely adopted in medical and life science researches. Although various physical and biological effects of FUS have been well-documented, there is still a lack of understanding and direct evidence on the biological mechanism of therapeutic cell ablation caused by high-intensity ultrasound (HIFU) and the subsequent wound healing responses. This study develops an enclosed cell culture device that synergistically combines non-invasive FUS stimulation and real-time, on-the-fly live-cell imaging, providing an in vitro platform to explore short and long-term biological effects of ultrasound. The process, mechanism, and wound healing response of cell ablation induced by HIFU are elucidated, revealing a unique mechanism, termed ultrasound-inflicted cellular mechanolysis, that is mediated by growing subcellular cavitation air bubbles under confined contact with cells. This provides a previously unappreciated mechanism for understanding the biomechanical principles of ultrasound-based ablative therapy. A post-ablation phantom layer is also revealed that serves as a guiding cue for collective cell migration during wound healing, thereby providing a biomimetic model for studying wound healing after HIFU-inflicted damage. Together, this study provides theoretical and technological basis for advancing the understanding of the biological effects of ultrasound-based ablative therapy and inspiring clinically relevant applications in the future.

Emerging Wearable Acoustic Sensing Technologies

Sound signals not only serve as the primary communication medium but also find application in fields such as medical diagnosis and fault detection. With public healthcare resources increasingly under pressure, and challenges faced by disabled individuals on a daily basis, solutions that facilitate low-cost private healthcare hold considerable promise. Acoustic methods have been widely studied because of their lower technical complexity compared to other medical solutions, as well as the high safety threshold of the human body to acoustic energy. Furthermore, with the recent development of artificial intelligence technology applied to speech recognition, speech recognition devices, and systems capable of assisting disabled individuals in interacting with scenes are constantly being updated. This review meticulously summarizes the sensing mechanisms, materials, structural design, and multidisciplinary applications of wearable acoustic devices applied to human health and human-computer interaction. Further, the advantages and disadvantages of the different approaches used in flexible acoustic devices in various fields are examined. Finally, the current challenges and a roadmap for future research are analyzed based on existing research progress to achieve more comprehensive and personalized healthcare.

Next generation bioelectronic medicine: making the case for non-invasive closed-loop autonomic neuromodulation

The field of bioelectronic medicine has advanced rapidly from rudimentary electrical therapies to cutting-edge closed-loop systems that integrate real-time physiological monitoring with adaptive neuromodulation. Early innovations, such as cardiac pacemakers and deep brain stimulation, paved the way for these sophisticated technologies. This review traces the historical and technological progression of bioelectronic medicine, culminating in the emerging potential of closed-loop devices for multiple disorders of the brain and body. We emphasize both invasive techniques, such as implantable devices for brain, spinal cord and autonomic regulation, while we introduce new prospects for non-invasive neuromodulation, including focused ultrasound and newly developed autonomic neurography enabling precise detection and titration of inflammatory immune responses. The case for closed-loop non-invasive autonomic neuromodulation (incorporating autonomic neurography and splenic focused ultrasound stimulation) is presented through its applications in conditions such as sepsis and chronic inflammation, illustrating its capacity to revolutionize personalized healthcare. Today, invasive or non-invasive closed-loop systems have yet to be developed that dynamically modulate autonomic nervous system function by responding to real-time physiological and molecular signals; it represents a transformative approach to therapeutic interventions and major opportunity by which the bioelectronic field may advance. Knowledge gaps remain and likely contribute to the lack of available closed loop autonomic neuromodulation systems, namely, (1) significant exogenous and endogenous noise that must be filtered out, (2) potential drift in the signal due to temporal change in disease severity and/or therapy induced neuroplasticity, and (3) confounding effects of exogenous therapies (e.g., concurrent medications that dysregulate autonomic nervous system functions). Leveraging continuous feedback and real-time adjustments may overcome many of these barriers, and these next generation systems have the potential to stand at the forefront of precision medicine, offering new avenues for individualized and adaptive treatment.

Rspo3-mediated metabolic liver zonation regulates systemic glucose metabolism and body mass in mice

The unique architecture of the liver consists of hepatic lobules, dividing the hepatic features of metabolism into 2 distinct zones, namely the pericentral and periportal zones, the spatial characteristics of which are broadly defined as metabolic zonation. R-spondin3 (Rspo3), a bioactive protein promoting the Wnt signaling pathway, regulates metabolic features especially around hepatic central veins. However, the functional impact of hepatic metabolic zonation, regulated by the Rspo3/Wnt signaling pathway, on whole-body metabolism homeostasis remains poorly understood. In this study, we analyze the local functions of Rspo3 in the liver and the remote actions of hepatic Rspo3 on other organs of the body by using murine models. Rspo3 expression analysis shows that Rspo3 expression patterns are spatiotemporally controlled in the murine liver such that it locates in the pericentral zones and converges after feeding, and the dynamics of these processes are disturbed in obesity. We find that viral-mediated induction of Rspo3 in hepatic tissue of obesity improves insulin resistance and prevents body weight gain by restoring attenuated organ insulin sensitivities, reducing adipose tissue enlargement and reversing overstimulated adaptive thermogenesis. Denervation of the hepatic vagus suppresses these remote effects, derived from hepatic Rspo3 induction, toward adipose tissues and skeletal muscle, suggesting that signals are transduced via the neuronal communication consisting of afferent vagal and efferent sympathetic nerves. Furthermore, the non-neuronal inter-organ communication up-regulating muscle lipid utilization is partially responsible for the ameliorations of both fatty liver development and reduced skeletal muscle quality in obesity. In contrast, hepatic Rspo3 suppression through Cre-LoxP-mediated recombination system exacerbates diabetes due to glucose intolerance and insulin resistance, promotes fatty liver development and decreases skeletal muscle quality, resulting in obesity. Taken together, our study results reveal that modulation of hepatic Rspo3 contributes to maintaining systemic glucose metabolism and body composition via a newly identified inter-organ communication mechanism.

Low-intensity pulsed ultrasound improves metabolic dysregulation in obese mice by suppressing inflammation and extracellular matrix remodeling

Chronic inflammation in white adipose tissue is crucial in obesity and related metabolic disorders. Low-intensity pulsed ultrasound (LIPUS) is renowned for its anti-inflammatory effects as a non-invasive treatment, yet its precise role in obesity has been uncertain. Our study investigates the therapeutic effect of LIPUS and its underlying mechanism on obesity in mice, thereby offering a novel approach for non-invasive treatment of obesity and associated metabolic disorders for human. Male C57BL/6J mice aged 10 weeks were fed a high-fat diet (HFD) for 8 weeks to establish obesity model, then underwent 8 weeks of LIPUS (frequency: 1.0 MHz, duty cycle: 20 %, Isata: 58-61 mW/cm2, 20 min per day) stimulation of the epididymal white adipose tissue. Fat and lean mass were measured using nuclear magnetic resonance (NMR), while energy homeostasis was evaluated using metabolic cages. Insulin resistance was assessed using glucose tolerance tests (GTT) and insulin tolerance tests (ITT). Regulatory mechanisms were explored using RNA sequencing. Results showed that LIPUS significantly reduced obesity markers in obese mice, including body and adipose tissue weight, and improved insulin resistance, without affecting food intake. RNA sequencing showed 250 up-regulated and 351 down-regulated genes between HFD-LIPUS group and HFD-Sham group, suggesting anti-inflammatory action. Quantitative PCR confirmed reduced pro-inflammatory gene expression and macrophage infiltration in eWAT. Gene set enrichment analysis showed decreased NF-κB signaling and extracellular matrix-receptor interactions in LIPUS-treated mice. Thus, LIPUS effectively mitigates metabolic dysregulation in HFD-induced obesity through inflammation suppression and extracellular matrix remodeling, which provides a potential physical therapy for metabolic syndrome in clinic.

Noninvasive closed-loop acoustic brain-computer interface for seizure control

Rationale: The brain-computer interface (BCI) is core tasks in comprehensively understanding the brain, and is one of the most significant challenges in neuroscience. The development of novel non-invasive neuromodulation technique will drive major innovations and breakthroughs in the field of BCI. Methods: We develop a new noninvasive closed-loop acoustic brain-computer interface (aBCI) for decoding the seizure onset based on the electroencephalography and triggering ultrasound stimulation of the vagus nerve to terminate seizures. Firstly, we create the aBCI system and decode the onset of seizure via a multi-level threshold model based on the analysis of wireless-collected electroencephalogram (EEG) signals recorded from above the hippocampus. Then, the different acoustic parameters induced acoustic radiation force were used to stimulate the vagus nerve in a rat model of epilepsy-induced by pentylenetetrazole. Finally, the results of epileptic EEG signal triggering ultrasound stimulation of the vagus nerve to control seizures. In addition, the mechanism of aBCI control seizures were investigated by real-time quantitative polymerase chain reaction (RT-qPCR). Results: In a rat model of epilepsy, the aBCI system selectively actives mechanosensitive neurons in the nodose ganglion while suppressing neuronal excitability in the hippocampus and amygdala, and stops seizures rapidly upon ultrasound stimulation of the vagus nerve. Physical transection or chemical blockade of the vagus nerve pathway abolish the antiepileptic effects of aBCI. In addition, aBCI shows significant antiepileptic effects compared to conventional vagus nerve electrical stimulation in an acute experiment. Conclusions: Closed-loop aBCI provides a novel, safe and effective tool for on-demand stimulation to treat abnormal neuronal discharges, opening the door to next generation non-invasive BCI.

Bridging the Gap: A Literature Review of Advancements in Obesity and Diabetes Mellitus Management

This literature review explores advancements in obesity and diabetes mellitus diagnosis and treatment, highlighting recent innovations that promise more personalized and effective healthcare interventions. For obesity diagnosis, traditional methods like body mass index (BMI) calculations are now complemented by bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) scans, with emerging biomarkers from “omics” technologies. Diabetes diagnosis has advanced with standard hemoglobin A1c (HbA1c) testing supplemented by novel measures such as advanced glycation end products (AGEs) and autoantibodies, alongside the use of artificial intelligence to enhance diagnostic accuracy. Treatment options for obesity are expanding beyond traditional methods. Minimally invasive bariatric surgeries, endoscopic procedures, fecal microbiota transplants (FMTs), and pharmaceuticals like GLP-1 receptor agonists (semaglutide, tirzepatide) show promising results. Cognitive behavioral therapy (CBT) and prescription digital therapeutics (PDTs) are also valuable tools for weight management. Diabetes treatment is also undergoing a transformation. Ultra-long-acting insulins and innovative oral insulin delivery methods are on the horizon. SGLT2 inhibitors and GLP-1 receptor agonists are proving to be effective medications for blood sugar control. Continuous glucose monitoring (CGM) systems and closed-loop insulin delivery are revolutionizing diabetes management, while stem cell therapy holds promise for the future. By integrating advanced diagnostic tools with personalized treatment plans, obesity and diabetes care are entering a new era. This personalized approach empowers patients and paves the way for improved health outcomes and a better quality of life.

Ultrasound Neuromodulation of an Anti-Inflammatory Pathway at the Spleen Improves Experimental Pulmonary Hypertension

BACKGROUND

Inflammation is pathogenically implicated in pulmonary arterial hypertension; however, it has not been adequately targeted therapeutically. We investigated whether neuromodulation of an anti-inflammatory neuroimmune pathway involving the splenic nerve using noninvasive, focused ultrasound stimulation of the spleen (sFUS) can improve experimental pulmonary hypertension.

METHODS

Pulmonary hypertension was induced in rats either by Sugen 5416 (20 mg/kg SQ) injection, followed by 21 (or 35) days of hypoxia (sugen/hypoxia model), or by monocrotaline (60 mg/kg IP) injection (monocrotaline model). Animals were randomized to receive either 12-minute-long sessions of sFUS daily or sham stimulation for 14 days. Catheterizations, echocardiography, indices of autonomic function, lung and heart histology and immunohistochemistry, spleen flow cytometry, and lung single-cell RNA sequencing were performed after treatment to assess the effects of sFUS.

RESULTS

Splenic denervation right before induction of pulmonary hypertension results in a more severe disease phenotype. In both sugen/hypoxia and monocrotaline models, sFUS treatment reduces right ventricular systolic pressure by 25% to 30% compared with sham treatment, without affecting systemic pressure, and improves right ventricular function and autonomic indices. sFUS reduces wall thickness, apoptosis, and proliferation in small pulmonary arterioles, suppresses CD3+ and CD68+ cell infiltration in lungs and right ventricular fibrosis and hypertrophy and lowers BNP (brain natriuretic peptide). Beneficial effects persist for weeks after sFUS discontinuation and are more robust with early and longer treatment. Splenic denervation abolishes sFUS therapeutic benefits. sFUS partially normalizes CD68+ and CD8+ T-cell counts in the spleen and downregulates several inflammatory genes and pathways in nonclassical and classical monocytes and macrophages in the lung. Differentially expressed genes in those cell types are significantly enriched for human pulmonary arterial hypertension-associated genes.

CONCLUSIONS

sFUS causes dose-dependent, sustained improvement of hemodynamic, autonomic, laboratory, and pathological manifestations in 2 models of experimental pulmonary hypertension. Mechanistically, sFUS normalizes immune cell populations in the spleen and downregulates inflammatory genes and pathways in the lung, many of which are relevant in human disease.

Transspinal Focused Ultrasound Suppresses Spinal Reflexes in Healthy Rats

OBJECTIVES

Low-intensity, focused ultrasound (FUS) is an emerging noninvasive neuromodulation approach, with improved spatial and temporal resolution and penetration depth compared to other noninvasive electrical stimulation strategies. FUS has been used to modulate circuits in the brain and the peripheral nervous system, however, its potential to modulate spinal circuits is unclear. In this study, we assessed the effect of trans-spinal FUS (tsFUS) on spinal reflexes in healthy rats.

MATERIALS AND METHODS

tsFUS targeting different spinal segments was delivered for 1 minute, under anesthesia. Monosynaptic H-reflex of the sciatic nerve, polysynaptic flexor reflex of the sural nerve, and withdrawal reflex tested with a hot plate were measured before, during, and after tsFUS.

RESULTS

tsFUS reversibly suppresses the H-reflex in a spinal segment-, acoustic pressure- and pulse-repetition frequency (PRF)-dependent manner. tsFUS with high PRF augments the degree of homosynaptic depression of the H-reflex observed with paired stimuli. It suppresses the windup of components of the flexor reflex associated with slower, C-afferent, but not faster, A- afferent fibers. Finally, it increases the latency of the withdrawal reflex. tsFUS does not elicit neuronal loss in the spinal cord.

CONCLUSIONS

Our study provides evidence that tsFUS reversibly suppresses spinal reflexes and suggests that tsFUS could be a safe and effective strategy for spinal cord neuromodulation in disorders associated with hyperreflexia, including spasticity after spinal cord injury and painful syndromes.

Noninvasive imaging-guided ultrasonic neurostimulation with arbitrary 2D patterns and its application for high-quality vision restoration

Retinal degeneration, a leading cause of irreversible low vision and blindness globally, can be partially addressed by retina prostheses which stimulate remaining neurons in the retina. However, existing electrode-based treatments are invasive, posing substantial risks to patients and healthcare providers. Here, we introduce a completely noninvasive ultrasonic retina prosthesis, featuring a customized ultrasound two-dimensional array which allows for simultaneous imaging and stimulation. With synchronous three-dimensional imaging guidance and auto-alignment technology, ultrasonic retina prosthesis can generate programmed ultrasound waves to dynamically and precisely form arbitrary wave patterns on the retina. Neuron responses in the brain's visual center mirrored these patterns, evidencing successful artificial vision creation, which was further corroborated in behavior experiments. Quantitative analysis of the spatial-temporal resolution and field of view demonstrated advanced performance of ultrasonic retina prosthesis and elucidated the biophysical mechanism of retinal stimulation. As a noninvasive blindness prosthesis, ultrasonic retina prosthesis could lead to a more effective, widely acceptable treatment for blind patients. Its real-time imaging-guided stimulation strategy with a single ultrasound array, could also benefit ultrasound neurostimulation in other diseases.

Flexible Organic Photovoltaic-Powered Hydrogel Bioelectronic Dressing With Biomimetic Electrical Stimulation for Healing Infected Diabetic Wounds

Electrical stimulation (ES) is proposed as a therapeutic solution for managing chronic wounds. However, its widespread clinical adoption is limited by the requirement of additional extracorporeal devices to power ES-based wound dressings. In this study, a novel sandwich-structured photovoltaic microcurrent hydrogel dressing (PMH dressing) is designed for treating diabetic wounds. This innovative dressing comprises flexible organic photovoltaic (OPV) cells, a flexible micro-electro-mechanical systems (MEMS) electrode, and a multifunctional hydrogel serving as an electrode-tissue interface. The PMH dressing is engineered to administer ES, mimicking the physiological injury current occurring naturally in wounds when exposed to light; thus, facilitating wound healing. In vitro experiments are performed to validate the PMH dressing's exceptional biocompatibility and robust antibacterial properties. In vivo experiments and proteomic analysis reveal that the proposed PMH dressing significantly accelerates the healing of infected diabetic wounds by enhancing extracellular matrix regeneration, eliminating bacteria, regulating inflammatory responses, and modulating vascular functions. Therefore, the PMH dressing is a potent, versatile, and effective solution for diabetic wound care, paving the way for advancements in wireless ES wound dressings.

Ultrasound-Triggered Amoxicillin Release from Chitosan/Ethylene Glycol Diglycidyl Ether/Amoxicillin Hydrogels Having a Covalently Bonded Network

An antibiotic release system triggered by ultrasound (US) was investigated using chitosan (CS)/ethylene glycol diglycidyl ether (EGDE) hydrogel carriers with amoxicillin (Amox) drug. Different CS concentrations of 1.5, 2, 2.5, and 3 wt % were gelled with EGDE and Amox was entrapped in the hydrogel carrier; the accelerated release was observed as triggered by 43 kHz US exposure at different US output powers ranging from 0 to 35 W. Among these CS hydrogel systems, the degree of accelerated Amox release depended on the CS concentration for the hydrogelation and the matrix with 2 wt % CS exhibited efficient Amox release at 35 W US power with around 19 μg/mL. The drug released with time was fitted with Higuchi and Korsmeyer-Peppas models, and the enhancement was caused by US aiding drug diffusion within the hydrogel matrix by a non-Fickian diffusion mechanism. The US effect on the viscoelasticity of the hydrogel matrix indicated that the matrix became somewhat softened by the US exposure to the dense hydrogels for 2.5 and 3% CS/EGDE, while the degree of softening was slightly marked in the CS/EGDE hydrogels prepared with 1.5 and 2% CS concentration. Such US softening also aided drug diffusion within the hydrogel matrix, suggesting an enhanced Amox release.

High-Performing and Capacitive-Matched Triboelectric Implants Driven by Ultrasound

In implantable bioelectronics, which aim for semipermanent use of devices, biosafe energy sources and packaging materials to protect devices are essential elements. However, research so far has been conducted in a direction where they cannot coexist. Here, the development of capacitance-matched triboelectric implants driven is reported by ultrasound under 500 mW cm-2 safe intensity and realize a battery-free, miniatured, and wireless neurostimulator with full titanium (Ti) packaging. The triboelectric implant with high dielectric composite, which has ultralow output impedance, can efficiently deliver sufficient power to generate the stimulation pulse without an energy-storing battery, despite ultrasound attenuation due to the Ti, and has the highest energy transmission efficiency among those reported so far. In vivo study using a rat model demonstrated that the proposed device system is an effective solution for relieving urinary symptoms. These achievements provide a significant step toward permanently implantable devices for controlling human organs and treating various diseases.

[Research advances in neuromodulation techniques for blood glucose regulation and diabetes intervention]

Diabetes and its complications that seriously threaten the health and life of human, has become a public health problem of global concern. Glycemic control remains a major focus in the treatment and management of patients with diabetes. The traditional lifestyle interventions, drug therapies, and surgeries have benefited many patients with diabetes. However, due to problems such as poor patient compliance, drug side effects, and limited surgical indications, there are still patients who fail to effectively control their blood glucose levels. With the development of bioelectronic medicine, neuromodulation techniques have shown great potential in the field of glycemic control and diabetes intervention with its unique advantages. This paper mainly reviewed the research advances and latest achievements of neuromodulation technologies such as peripheral nerve electrical stimulation, ultrasound neuromodulation, and optogenetics in blood glucose regulation and diabetes intervention, analyzed the existing problems and presented prospects for the future development trend to promote clinical research and application of neuromodulation technologies in the treatment of diabetes.

Rib detection using pitch-catch ultrasound and classification algorithms for a novel ultrasound therapy device

BACKGROUND

Noninvasive ultrasound (US) has been used therapeutically for decades, with applications in tissue ablation, lithotripsy, and physical therapy. There is increasing evidence that low intensity US stimulation of organs can alter physiological and clinical outcomes for treatment of health disorders including rheumatoid arthritis and diabetes. One major translational challenge is designing portable and reliable US devices that can be used by patients in their homes, with automated features to detect rib location and aid in efficient transmission of energy to organs of interest. This feasibility study aimed to assess efficacy in rib bone detection without conventional imaging, using a single channel US pitch-catch technique integrated into an US therapy device to detect pulsed US reflections from ribs.

METHODS

In 20 healthy volunteers, the location of the ribs and spleen were identified using a diagnostic US imaging system. Reflected ultrasound signals were recorded at five positions over the spleen and adjacent ribs using the therapy device. Signals were classified as between ribs (intercostal), partially over a rib, or fully over a rib using four models: threshold-based time domain classification, threshold-based frequency domain classification, logistic regression, and support vector machine (SVM).

RESULTS

SVM performed best overall on the All Participants cohort with accuracy up to 96.25%. All models' accuracies were improved by separating participants into two cohorts based on Body Mass Index (BMI) and re-fitting each model. After separation into Low BMI and High BMI cohorts, a simple time-thresholding approach achieved accuracies up to 100% and 93.75%, respectively.

CONCLUSION

These results demonstrate that US reflection signal classification can accurately provide low complexity, real-time automated onboard rib detection and user feedback to advance at-home therapeutic US delivery.

Functional material-mediated wireless physical stimulation for neuro-modulation and regeneration

Nerve injuries and neurological diseases remain intractable clinical challenges. Despite the advantages of stem cell therapy in treating neurological disorders, uncontrollable cell fates and loss of cell function in vivo are still challenging. Recently, increasing attention has been given to the roles of external physical signals, such as electricity and ultrasound, in regulating stem cell fate as well as activating or inhibiting neuronal activity, which provides new insights for the treatment of neurological disorders. However, direct physical stimulations in vivo are short in accuracy and safety. Functional materials that can absorb energy from a specific physical field exerted in a wireless way and then release another localized physical signal hold great advantages in mediating noninvasive or minimally invasive accurate indirect physical stimulations to promote the therapeutic effect on neurological disorders. In this review, the mechanism by which various physical signals regulate stem cell fate and neuronal activity is summarized. Based on these concepts, the approaches of using functional materials to mediate indirect wireless physical stimulation for neuro-modulation and regeneration are systematically reviewed. We expect that this review will contribute to developing wireless platforms for neural stimulation as an assistance for the treatment of neurological diseases and injuries.

Investigation of liver-targeted peripheral focused ultrasound stimulation (pFUS) and its effect on glucose homeostasis and insulin resistance in type 2 diabetes mellitus: a proof of concept, phase 1 trial

BACKGROUND

Mechanical waves produced by ultrasound pulses have been shown to activate mechanosensitive ion channels and modulate peripheral nerves. However, while peripheral ultrasound neuromodulation has been demonstrated in vitro and in pre-clinical models, there have been few reports of clinical tests.

AIM

We modified a diagnostic imaging system for ultrasound neuromodulation in human subjects. We report the first safety and feasibility outcomes in subjects with type 2 diabetes (T2D) mellitus and discuss these outcomes in relation to previous pre-clinical results.

DESIGN

The study was performed as an open label feasibility study to assess the effects of hepatic ultrasound (targeted to the porta hepatis) on glucometabolic parameters in subjects with T2D. Stimulation (peripheral focused ultrasound stimulation treatment) was performed for 3 days (i.e. 15 min per day), preceded by a baseline examination and followed by a 2-week observation period.

METHODS

Multiple metabolic assays were employed including measures of fasting glucose and insulin, insulin resistance and glucose metabolism. The safety and tolerability were also assessed by monitoring adverse events, changes in vital signs, electrocardiogram parameters and clinical laboratory measures.

RESULTS AND CONCLUSION

We report post-pFUS trends in several outcomes that were consistent with previous pre-clinical findings. Fasting insulin was lowered, resulting in a reduction of HOMA-IR scores (P-value 0.01; corrected Wilcoxon signed-rank test). Additional safety and exploratory markers demonstrated no device-related adverse impact of pFUS. Our findings demonstrate that pFUS represents a promising new treatment modality that could be used as a non-pharmaceutical adjunct or even alternative to current drug treatments in diabetes.

Combining Celiac and Hepatic Vagus Nerve Neuromodulation Reverses Glucose Intolerance and Improves Glycemic Control in Pre- and Overt-Type 2 Diabetes Mellitus

Neurological disorders and type 2 diabetes mellitus (T2DM) are deeply intertwined. For example, autonomic neuropathy contributes to the development of T2DM and continued unmanaged T2DM causes further progression of nerve damage. Increasing glycemic control has been shown to prevent the onset and progression of diabetic autonomic neuropathies. Neuromodulation consisting of combined stimulation of celiac vagal fibers innervating the pancreas with concurrent electrical blockade of neuronal hepatic vagal fibers innervating the liver has been shown to increase glycemic control in animal models of T2DM. The present study demonstrated that the neuromodulation reversed glucose intolerance in alloxan-treated swine in both pre- and overt stages of T2DM. This was demonstrated by improved performance on oral glucose tolerance tests (OGTTs), as assessed by area under the curve (AUC). In prediabetic swine (fasting plasma glucose (FPG) range: 101-119 mg/dL) the median AUC decreased from 31.9 AUs (IQR = 28.6, 35.5) to 15.9 AUs (IQR = 15.1, 18.3) p = 0.004. In diabetic swine (FPG range: 133-207 mg/dL) the median AUC decreased from 54.2 AUs (IQR = 41.5, 56.6) to 16.0 AUs (IQR = 15.4, 21.5) p = 0.003. This neuromodulation technique may offer a new treatment for T2DM and reverse glycemic dysregulation at multiple states of T2DM involved in diabetic neuropathy including at its development and during progression.

Ultrasound Stimulation Potentiates Management of Diabetic Hyperglycemia

OBJECTIVE

Glucose homeostasis is the only way to manage diabetic progression as all medications used do not cure diabetes. This study was aimed at verifying the feasibility of lowering glucose with non-invasive ultrasonic stimulation.

METHODS

The ultrasonic device was homemade and controlled via a mobile application on the smartphone. Diabetes was induced in Sprague-Dawley rats through high-fat diets followed by streptozotocin injection. The treated acupoint CV12 was at the middle of the xiphoid and umbilicus of the diabetic rats. Parameters of ultrasonic stimulation were an operating frequency of 1 MHz, pulse repetition frequency of 15 Hz, duty cycle of 10% and sonication time of 30 min for a single treatment.

DISCUSSION

The diabetic rats exhibited a significant decrease of 11.5% ± 3.6% in blood glucose in 5 min of ultrasonic stimulation (p < 0.001). After the single treatment on the first day, third day and fifth day in the first week, the treated diabetic rats had a significantly small area under the curve of the glucose tolerance test (p < 0.05) compared with the untreated diabetic rats in the sixth week. Hematological analyses indicated that the serum concentrations of β-endorphin were significantly increased by 58% ± 71.9% (p < 0.05) and the insulin level was increased by 56% ± 88.2% (p = 0.15) without statistical significance after a single treatment.

CONCLUSION

Therefore, non-invasive ultrasound stimulation at an appropriate dose can produce a hypoglycemic effect and improve glucose tolerance for glucose homeostasis and may play a role as adjuvant therapy with diabetic medications in the future.

Focused ultrasound neuromodulation of the spleen activates an anti-inflammatory response in humans

Focused ultrasound stimulation (FUS) activates mechanosensitive ion channels and is emerging as a method of noninvasive neuromodulation. In preclinical studies, FUS of the spleen (sFUS) activates an anti-inflammatory neural pathway which suppresses acute and chronic inflammation. However, the relevance of sFUS for regulating inflammatory responses in humans is unknown. Here, we used a modified diagnostic ultrasound imaging system to target the spleen of healthy human subjects with 3 min of continuously swept or stationary focused pulsed ultrasound, delivered at three different energy levels within allowable safety exposure limits. Potential anti-inflammatory effects of sFUS were assessed by measuring sFUS-elicited changes in endotoxin-induced tumor necrosis factor (TNF) production in whole blood samples from insonified subjects. We found that stimulation with either continuously swept or focused pulsed ultrasound has an anti-inflammatory effect: sFUS lowers TNF production for >2 h, with TNF returning to baseline by 24 h following sFUS. This response is independent of anatomical target (i.e., spleen hilum or parenchyma) or ultrasound energy level. No clinical, biochemical, or hematological parameters are adversely impacted. This is the first demonstration that sFUS suppresses the normal inflammatory response in humans, with potential implications for noninvasive bioelectronic therapy of inflammatory disorders.

Current Trends in Nanotheranostics: A Concise Review on Bioimaging and Smart Wearable Technology

The area of interventional nanotheranostics combines the use of interventional procedures with nanotechnology for the detection and treatment of physiological disorders. Using catheters or endoscopes, for example, interventional techniques make use of minimally invasive approaches to diagnose and treat medical disorders. It is feasible to increase the precision of these approaches and potency by integrating nanotechnology. To visualize and target various parts of the body, such as tumors or obstructed blood veins, one can utilize nanoscale probes or therapeutic delivery systems. Interventional nanotheranostics offers targeted, minimally invasive therapies that can reduce side effects and enhance patient outcomes, and it has the potential to alter the way that many medical illnesses are handled. Clinical enrollment and implementation of such laboratory scale theranostics approach in medical practice is promising for the patients where the user can benefit by tracking its physiological state. This review aims to introduce the most recent advancements in the field of clinical imaging and diagnostic techniques as well as newly developed on-body wearable devices to deliver therapeutics and monitor its due alleviation in the biological milieu.

Imaging Guided Endogenic H2 -Augmented Electrochemo-Sonodynamic Domino Co-therapy of Tumor in Vivo

Precise and on-demand release of sufficient hydrogen (H₂ ) to tumor sites remains a key challenge for emerging H₂ -oncotherapy, and little is known about the physiological effects of "abundant" H₂ on complex tumor microenvironments (TME). Here, a highly efficient and cost-effective imaging-guided/-assessed H₂ -therapy of tumors based on a joint electrochemo-sonodynamic treatment (H₂ -EC/SD co-therapy) with strong "domino effect" triggered by endogenous H₂ generation at tumor sites is reported to speedily eliminate tumor tissue (≤80 mm³ ) within 1 day. Adequate H₂ is controllably generated in tumor sites through mild electrochemistry in vivo due to acidic TME by using clinical acupuncture Fe needles as electrodes. Besides starvation damage due to gas blockage/destruction of vessels, nano-/micro-bubbles of H₂ formed in situ can elevate the tumor's internal temperature and burst vessels to further destroy the tumor under ultrasound irradiation. Remarkably, vulnerable homeostasis of TME is disturbed as H₂ also participates in the physiological activity of tumor cells, leading to tumor dysfunction. Last but not least, the body's inflammatory response to cancer is reduced after the treatment, which is beneficial for the body's immune system during post-treatment recovery. Based on all of these merits, the H₂ -EC/SD co-therapy provides a potentially safe and viable therapeutic strategy for future clinical applications.

Peripheral focused ultrasound stimulation and its applications: From therapeutics to human-computer interaction

Peripheral focused ultrasound stimulation (pFUS) has gained increasing attention in the past few decades, because it can be delivered to peripheral nerves, neural endings, or sub-organs. With different stimulation parameters, ultrasound stimulation could induce different modulation effects. Depending on the transmission medium, pFUS can be classified as body-coupled US stimulation, commonly used for therapeutics or neuromodulation, or as an air-coupled contactless US haptic system, which provides sensory inputs and allows distinct human-computer interaction paradigms. Despite growing interest in pFUS, the underlying working mechanisms remain only partially understood, and many applications are still in their infancy. This review focused on existing applications, working mechanisms, the latest progress, and future directions of pFUS. In terms of therapeutics, large-sample randomized clinical trials in humans are needed to translate these state of art techniques into treatments for specific diseases. The airborne US for human-computer interaction is still in its preliminary stage, but further efforts in task-oriented US applications might provide a promising interaction tool soon.

General-Purpose Ultrasound Neuromodulation System for Chronic, Closed-Loop Preclinical Studies in Freely Behaving Rodents

Transcranial focused ultrasound stimulation (tFUS) is an effective noninvasive treatment modality for brain disorders with high clinical potential. However, the therapeutic effects of ultrasound neuromodulation are not widely explored due to limitations in preclinical systems. The current preclinical studies are head-fixed, anesthesia-dependent, and acute, limiting clinical translatability. Here, this work reports a general-purpose ultrasound neuromodulation system for chronic, closed-loop preclinical studies in freely behaving rodents. This work uses microelectromechanical systems (MEMS) technology to design and fabricate a small and lightweight transducer capable of artifact-free stimulation and simultaneous neural recording. Using the general-purpose system, it can be observed that state-dependent ultrasound neuromodulation of the prefrontal cortex increases rapid eye movement (REM) sleep and protects spatial working memory to REM sleep deprivation. The system will allow explorative studies in brain disease therapeutics and neuromodulation using ultrasound stimulation for widespread clinical adoption.

Bioelectronic medicine: Preclinical insights and clinical advances

The nervous system maintains homeostasis and health. Homeostatic disruptions underlying the pathobiology of many diseases can be controlled by bioelectronic devices targeting CNS and peripheral neural circuits. New insights into the regulatory functions of the nervous system and technological developments in bioelectronics drive progress in the emerging field of bioelectronic medicine. Here, we provide an overview of key aspects of preclinical research, translation, and clinical advances in bioelectronic medicine.

Activation of Mechanosensitive Ion Channels by Ultrasound

Mechanosensitive channels (MSCs) play an important role in how cells transduce mechanical stimuli into electrical or chemical signals, which provides an interventional possibility through the manipulation of ion channel activation using different mechanical stimulation conditions. With good spatial resolution and depth of penetration, ultrasound is often proposed as the tool of choice for such therapeutic applications. Despite the identification of many ion channels as mechanosensitive in recent years, only a limited number of MSCs have been reported to be activated by ultrasound with substantial evidence. Furthermore, although many therapeutic implications using ultrasound have been explored, few offered insights into the molecular basis and the biological effects induced by ultrasound in relieving pain and accelerate tissue healing. In this review, we examined the literature, in particular studies that provided evidence of cellular responses to ultrasound, with and without the target ion channels. The ultrasound activation conditions were then summarized for these ion channels, and these conditions were related to their mode of activation based on the current biological concepts. The overall goal is to bridge the results relating to the activation of MSCs that is specific for ultrasound with the current knowledge in molecular structure and the available physiological evidence that may have facilitated such phenomena. We discussed how collating the information revealed by available scientific investigations helps in the design of a more effective stimulus device for the proposed translational purposes. Traditionally, studies on the effects of ultrasound have focused largely on its mechanical and physical interaction with the targeted tissue through thermal-based therapies as well as non-thermal mechanisms including ultrasonic cavitation; gas body activation; the direct action of the compressional, tensile and shear stresses; radiation force; and acoustic streaming. However, the current review explores and attempts to establish whether the application of low-intensity ultrasound may be associated with the activation of specific MSCs, which in turn triggers relevant cell signaling as its molecular mechanism in achieving the desired therapeutic effects. Non-invasive brain stimulation has recently become an area of intense research interest for rehabilitation, and the implication of low-intensity ultrasound is particularly critical given the need to minimize heat generation to preserve tissue integrity for such applications.

Ultrasound Neuromodulation of the Spleen Has Time-Dependent Anti-Inflammatory Effect in a Pneumonia Model

Interfaces between the nervous and immune systems have been shown essential for the coordination and regulation of immune responses. Non-invasive ultrasound stimulation targeted to the spleen has recently been shown capable of activating one such interface, the splenic cholinergic anti-inflammatory pathway (CAP). Over the past decade, CAP and other neuroimmune pathways have been activated using implanted nerve stimulators and tested to prevent cytokine release and inflammation. However, CAP studies have typically been performed in models of severe, systemic (e.g., endotoxemia) or chronic inflammation (e.g., collagen-induced arthritis or DSS-induced colitis). Herein, we examined the effects of activation of the splenic CAP with ultrasound in a model of local bacterial infection by lung instillation of 10⁵ CFU of Streptococcus pneumoniae. We demonstrate a time-dependent effect of CAP activation on the cytokine response assay during infection progression. CAP activation-induced cytokine suppression is absent at intermediate times post-infection (16 hours following inoculation), but present during the early (4 hours) and later phases (48 hours). These results indicate that cytokine inhibition associated with splenic CAP activation is not observed at all timepoints following bacterial infection and highlights the importance of further studying neuroimmune interfaces within the context of different immune system and inflammatory states.

Strategies for precision vagus neuromodulation

The vagus nerve is involved in the autonomic regulation of physiological homeostasis, through vast innervation of cervical, thoracic and abdominal visceral organs. Stimulation of the vagus with bioelectronic devices represents a therapeutic opportunity for several disorders implicating the autonomic nervous system and affecting different organs. During clinical translation, vagus stimulation therapies may benefit from a precision medicine approach, in which stimulation accommodates individual variability due to nerve anatomy, nerve-electrode interface or disease state and aims at eliciting therapeutic effects in targeted organs, while minimally affecting non-targeted organs. In this review, we discuss the anatomical and physiological basis for precision neuromodulation of the vagus at the level of nerve fibers, fascicles, branches and innervated organs. We then discuss different strategies for precision vagus neuromodulation, including fascicle- or fiber-selective cervical vagus nerve stimulation, stimulation of vagal branches near the end-organs, and ultrasound stimulation of vagus terminals at the end-organs themselves. Finally, we summarize targets for vagus neuromodulation in neurological, cardiovascular and gastrointestinal disorders and suggest potential precision neuromodulation strategies that could form the basis for effective and safe therapies.