Vagus nerve stimulation inhibits cytokine production and attenuates disease severity in rheumatoid arthritis

Vagotomy and the incidence of rheumatoid arthritis and osteoarthritis: a Danish register-based study

OBJECTIVES

Given the potential role of vagus nerve stimulation in treating rheumatoid arthritis (RA), we examined the incidence of RA and osteoarthritis (OA) in patients who underwent different forms of vagotomy that disparately affect the inflammatory reflex.

METHODS

Using nationwide health registries, we constructed cohorts of patients in Denmark who underwent truncal or superselective vagotomy between 1977 and 1995 and comparison members from the general population matched 10:1 on birth year, sex, and calendar year. We identified incident RA or OA and used Cox proportional hazards models to compute adjusted hazard ratios (aHRs) and corresponding 95% CI.

RESULTS

Our cohorts consisted of 2,260 truncal vagotomy patients matched with 22,610 comparators, and 3,810 superselective vagotomy patients matched with 38,090 comparators. The incidence rate (IR) of RA per 1,000 person-years (95% CI) in the truncal vagotomy cohort was 10.2 (6.5-15.3) versus 7.2 (6.1-8.4) in the matched comparison cohort. The aHR (95% CI) for RA development was 2.62 (1.47-4.67) in the truncal vagotomy cohort and 1.05 (0.51-2.17) in the superselective vagotomy cohort, with respect to comparison cohorts. The risk of developing OA was not significantly different for either vagotomy cohort compared with comparison cohorts.

CONCLUSION

Truncal vagotomy was associated with an increased incidence of RA; this association was not observed with superselective vagotomy. No association with either form of vagotomy was seen with OA. These findings support the hypothesis that disruption of vagus nerve signaling impacts the inflammatory reflex and contributes to the development of RA.

Scaling of vagus nerve stimulation parameters does not achieve equivalent nerve responses across species

BACKGROUND

Previous efforts to translate vagus nerve stimulation (VNS) therapies from preclinical studies to human clinical applications (e.g., for stroke, heart failure, and inflammatory diseases) did not account for individual- or species-specific differences in nerve responses when selecting stimulation parameters. Lack of explicit consideration for producing equivalent nerve responses could contribute to clinical outcomes not replicating promising results from preclinical animal studies.

METHODS

We used models of VNS built with ASCENT (Musselman, PLoS Comput Biol 17:e1009285, 2021) to quantify nerve responses across species and simulate translation of VNS therapies via either recycling or linear scaling of stimulation parameters. For humans (n = 9) and pigs (n = 12), we used previously validated computational models with the standard clinical helical cuff electrode on individual-specific nerve morphologies (Musselman, J Neural Eng 20:acda64, 2023b). We also modeled rat VNS (n = 9) with the Micro-Leads Neuro bipolar cuff. We calculated thresholds for fiber activation (A-, B-, and C-fibers) with biphasic rectangular pulses (0.13, 0.25, 0.5 ms). We defined "K" as the ratio of activation thresholds between a pair of individuals. We used a mixed model ANOVA on the natural logarithm of K to test for differences in inter-species Ks across fiber types and pulse widths. Lastly, using the same nerve morphologies and application-specific device design (cuff and waveform), we developed models to predict nerve responses in chronic human and rat VNS studies for treatment of stroke, inflammation, and heart failure.

RESULTS

Depending on the individual and species, the activation amplitude required to produce a given nerve response varied widely. Thus, applying the same VNS parameters across individuals within a species produced a large range of nerve responses. Further, applying the same or linearly scaled stimulation amplitudes across species also produced highly variable responses. Ks were greater for B fibers than A fibers (p < 0.0001) and decreased with longer pulse widths (p < 0.0001 between consecutive pairs).

CONCLUSIONS

The results highlight the need for systematic approaches to select stimulation parameters that account for individual- and species-specific differences in nerve responses to stimulation. Such parameter tuning may lead to higher response rates and greater therapeutic benefits from VNS therapies.

Control of spatiotemporal activation of organ-specific fibers in the swine vagus nerve by intermittent interferential current stimulation

Vagus nerve stimulation (VNS) is emerging as potential treatment for several chronic diseases. However, limited control of fiber activation, e.g., to promote desired effects over side effects, restricts clinical translation. Towards that goal, we describe a VNS method consisting of intermittent, interferential sinusoidal current stimulation (i2CS) through multi-contact epineural cuffs. In experiments in anesthetized swine, i2CS elicits nerve potentials and organ responses, from lungs and laryngeal muscles, that are distinct from equivalent non-interferential sinusoidal stimulation. Resection and micro-CT imaging of a previously stimulated nerve, to resolve anatomical trajectories of nerve fascicles, demonstrate that i2CS responses are explained by activation of organ-specific fascicles rather than the entire nerve. Physiological responses in swine and activity of single fibers in anatomically realistic, physiologically validated biophysical vagus nerve models indicate that i2CS reduces fiber activation at the interference focus. Experimental and modeling results demonstrate that current steering and beat and repetition frequencies predictably shape the spatiotemporal pattern of fiber activation, allowing tunable and precise control of nerve and organ responses. When compared to equivalent sinusoidal stimulation in the same animals, i2CS produces reduced levels of a side-effect by larger laryngeal fibers, while attaining similar levels of a desired effect by smaller bronchopulmonary fibers.

B cells modulate lung antiviral inflammatory responses via the neurotransmitter acetylcholine

The rapid onset of innate immune defenses is critical for early control of viral replication in an infected host and yet it can also lead to irreversible tissue damage, especially in the respiratory tract. Sensitive regulators must exist that modulate inflammation, while controlling the infection. In the present study, we identified acetylcholine (ACh)-producing B cells as such early regulators. B cells are the most prevalent ACh-producing leukocyte population in the respiratory tract demonstrated with choline acetyltransferase (ChAT)-green fluorescent protein (GFP) reporter mice, both before and after infection with influenza A virus. Mice lacking ChAT in B cells, disabling their ability to generate ACh (ChatBKO), but not those lacking ChAT in T cells, significantly, selectively and directly suppressed α7-nicotinic-ACh receptor-expressing interstitial, but not alveolar, macrophage activation and their ability to secrete tumor necrosis factor (TNF), while better controlling virus replication at 1 d postinfection. Conversely, TNF blockade via monoclonal antibody treatment increased viral loads at that time. By day 10 of infection, ChatBKO mice showed increased local and systemic inflammation and reduced signs of lung epithelial repair despite similar viral loads and viral clearance. Thus, B cells are key participants of an immediate early regulatory cascade that controls lung tissue damage after viral infection, shifting the balance toward reduced inflammation at the cost of enhanced early viral replication.

Neural-activity-regulated and glia-mediated control of brain lymphatic development

The nervous system regulates peripheral immune responses under physiological and pathological conditions, but the brain's impact on immune system development remains unknown. Meningeal mural lymphatic endothelial cells (muLECs), embedded in the leptomeninges, form an immune niche surrounding the brain that contributes to brain immunosurveillance. Here, we report that the brain controls the development of muLECs via a specialized glial subpopulation, slc6a11b+ radial astrocytes (RAs), a process modulated by neural activity in zebrafish. slc6a11b+ RAs, with processes extending to the meninges, govern muLEC formation by expressing vascular endothelial growth factor C (vegfc). Moreover, neural activity regulates muLEC development, and this regulation requires Vegfc in slc6a11b+ RAs. Intriguingly, slc6a11b+ RAs cooperate with calcium-binding EGF domain 1 (ccbe1)+ fibroblasts to restrict muLEC growth on the brain surface via controlling mature Vegfc distribution. Thus, our study uncovers a glia-mediated and neural-activity-regulated control of brain lymphatic development and highlights the importance of inter-tissue cellular cooperation in development.

Neuroimmune circuits in the plaque and bone marrow regulate atherosclerosis

Atherosclerosis remains the leading cause of death globally. Although its focal pathology is atheroma that develops in arterial walls, atherosclerosis is a systemic disease involving contributions by many organs and tissues. It is now established that the immune system causally contributes to all phases of atherosclerosis. Recent and emerging evidence positions the nervous system as a key modulator of inflammatory processes that underlie atherosclerosis. This neuroimmune cross-talk, we are learning, is bidirectional, and immune-regulated afferent signalling is becoming increasingly recognized in atherosclerosis. Here, we summarize data and concepts that link the immune and nervous systems in atherosclerosis by focusing on two important sites, the arterial vessel and the bone marrow.

The Role of Neuroinflammation in the Comorbidity of Psychiatric Disorders and Internal Diseases

Psychiatric disorders and internal diseases frequently co-occur, posing significant challenges due to overlapping symptoms, shared pathophysiological mechanisms, and increased healthcare burdens. Neuroinflammation has emerged as a central mechanism linking these conditions, driven by systemic inflammation, hypothalamic-pituitary-adrenal (HPA) axis dysregulation, and autonomic nervous system (ANS) imbalance. This review synthesizes current evidence on the role of neuroinflammation in comorbid conditions such as depression, anxiety, cardiovascular disease, and diabetes mellitus, emphasizing bidirectional relationships and shared inflammatory pathways. This analysis identifies gaps in longitudinal studies, biomarker validation, and the integration of multidisciplinary care models. Emerging therapeutic approaches, including IL-6 inhibitors, vagus nerve stimulation, and behavioral interventions, show promise but remain underexplored in combined applications. Furthermore, disparities in research representation limit the generalizability of findings and highlight the need for inclusive clinical trials. Addressing these gaps through precision medicine, advanced biomarker monitoring technologies, and equitable healthcare strategies could transform the management of these complex comorbidities. By advancing our understanding of neuroinflammatory mechanisms and promoting integrated interventions, this review underscores the need for a collaborative, patient-centered approach to improve outcomes and reduce the global burden of psychiatric and internal disease comorbidities.

Stimulation of auricular vagus nerve ameliorates chronic stress induced metabolic syndrome via activation of Sirtuin-6

Chronic stress is one of the potential causes of the progression of metabolic syndrome (MS). Chronic stress decreases the release of Sirtuin-6 (SIRT6), which regulates MS by controlling glucose, insulin, lipids, and hypertension. Vagus nerve stimulation (VNS) activates SIRT6 via the cholinergic anti-inflammatory pathway (CAP). However, the effectiveness of VNS therapy for treating MS induced by chronic stress has not yet been studied. In this study, we first validated a rat model of chronic unpredictable stress (CUS) and assessed the characteristic features of MS. The CUS rats were exposed to random stressors daily for 8 weeks. The stress response was then confirmed by behavioral alteration and elevated serum corticosterone levels in rats, as measured by various behavioral tests and an ELISA kit, respectively. The MS characteristics in CUS rats were assessed using measurements of fasting blood glucose (FBG), systolic blood pressure (SBP), lipid indices, insulin levels, and HOMA-IR. The stressed animals demonstrated a rise in FBG, SBP, and insulin along with altered lipid indices. After CUS, the rats were treated with VNS (6 Hz, 1.0 ms, 6 V, for 40 min × 14 days, alternatively), and their metabolic activity and vagal flow were assessed. Moreover, SIRT6 and AMP-activated protein kinase (AMPK) expression in rats was also assessed by immunohistochemistry and mRNA expression of liver and pancreatic tissue. SIRT6 and AMPK expression was decreased in CUS animals. Interestingly, VNS treatment attenuated CUS induced MS-associated parameters. These results indicate that VNS may be a beneficial complementary and non-pharmacological method for managing CUS-associated MS.

The gut-organ axis: Clinical aspects and immune mechanisms

The gut-brain axis exemplifies the bidirectional connection between the intestines and the brain, as evidenced by the impact of severe stress on gastrointestinal symptoms including abdominal pain and diarrhea, and conversely, the influence of abdominal discomfort on mood. Clinical observations support the notion of the gut-brain connection, including an increased prevalence of inflammatory bowel disease (IBD) in patients with depression and anxiety, as well as the association of changes in the gut microbiota with neurological disorders such as multiple sclerosis, Parkinson's disease, stroke and Alzheimer's disease. The gut and brain communicate via complex mechanisms involving inflammatory cytokines, immune cells, autonomic nerves, and gut microbiota, which contribute to the pathogenesis in certain gut and brain diseases. Two primary pathways mediate the bidirectional information exchange between the intestinal tract and the brain: signal transduction through bloodstream factors, such as bacterial metabolites and inflammatory cytokines, and neural pathways, such as neurotransmitters and inflammatory cytokines within the autonomic nervous system through the interaction between the nerve cells and beyond. In recent years, the basic mechanisms of the pathophysiology of the gut-brain axis have been gradually elucidated. Beyond the gut-brain interaction, emerging evidence suggests the influence of the gut extends to other organs, such as the liver and lungs, through intricate inter-organ communication pathways. An increasing number of reports on this clinical and basic cross-organ interactions underscore the potential for better understanding and novel therapeutic strategies targeting inter-organs networks. Further clarification of interactions between multiorgans premises transformative insights into cross-organ therapeutic strategies.

Focused Ultrasound Neuromodulation to Peripheral Nerve System

Noninvasive focused ultrasound (FUS) has been applied in the treatment of various targets. Neuromodulation using FUS is emerging as a promising therapeutic modality for the central nerve system (CNS) with the advantages of deep penetration and precise targeting in the brain. This technique can also be applied to the peripheral nerve system (PNS). The principle of FUS and the mechanisms of neromodulation on PNS are summarized. Current experimental observations on the PNS targets are introduced to show their therapeutic effects. Discussion on the limitations and perspectives of this technology illustrates the pros and cons for future development. FUS provides a noninvasive, safe, and effective modality for neurotherapeutics. Although the relevant research on PNS is much less than that on CNS, the limited studies have already shown the satisfactory performance of FUS in comparison to the FDA-approved implanted device, especially the vagus nerve stimulation (VNS). Wide applications in clinics and fast development in technology are expected in the near future.

Use of laryngeal muscle evoked potential recording for experimental vagus nerve stimulation

The laryngeal muscle evoked potential (LMEP) is a neurophysiological outcome parameter that guarantees integrity of the nerve-electrode interface during experiments with vagus nerve stimulation (VNS). This paper discusses a large series of minimally invasive LMEP recordings in 46 female Lewis rats, implanted with a custom-made VNS electrode around the left cervical vagus nerve. After a 3-week recovery, LMEPs were recorded twice in each animal, with swapping the anode and cathode positions of the VNS electrode (polarity inversion). A VNS-induced LMEP was identified as the initial negative peak wave post-stimulation artifact, consistently recorded in all sweeps at a given stimulation output current. Latency was defined as the time from stimulation onset to this negative peak, and stimulation threshold as the lowest current showing a clear and reproducible LMEP. An LMEP response was shown by 37/46 animals (80.4%), with stimulation intensity threshold of 0.37 ± 0.27 mA and latency of 2.39 ± 0.45 ms. Administering the cathodic pulse phase first at the caudal electrode contact resulted in the shortest LMEP latencies (MWU: p = 0.049. 2.36 ± 0.43 ms vs. 2.41 ± 0.47 ms). Minimally invasive LMEP recording provides a feasible and reliable means for checking electrode functioning and correct implantation.

Progress on Direct Regulation of Systemic Immunity by the Central Nervous System

This article reviews the research progress on the direct regulation of the immune system by the central nervous system (CNS). The traditional "neuro-endocrine-immune" network model has confirmed the close connection between the CNS and the immune system. However, due to the complex mediating role of the endocrine system, its application in clinical treatment is limited. In recent years, the direct regulation of the peripheral immune system through the CNS has provided new methods for the clinical treatment of neuroimmune-related diseases. This article analyzes the changes in the peripheral immune system after CNS injury and summarizes the effects of various stimulation methods, including transcranial magnetic stimulation, transcranial electrical stimulation, deep brain stimulation, spinal cord stimulation, and vagus nerve stimulation, on the peripheral immune system. Additionally, it explores the clinical research progress and future development directions of these stimulation methods. It is proposed that these neural regulation techniques exhibit positive effects in reducing peripheral inflammation, protecting immune cells and organ functions, and improving immunosuppressive states, providing new perspectives and therapeutic potential for the treatment of immune-related diseases.

The physiology, anatomy and stimulation of the vagus nerve in epilepsy

The vagus nerve is the longest cranial nerve, with much of its territory residing outside the head, in the neck, chest and abdomen. Although belonging to the parasympathetic division of the autonomic nervous system, it is dominated by sensory axons originating in the heart, lungs and airways and the gastrointestinal tract. Electrical stimulation of the cervical vagus nerve via surgically implanted cuff electrodes has been used clinically for the treatment of drug-resistant epilepsy for three decades but has also shown efficacy in the treatment of drug-resistant depression and certain gastrointestinal disorders. Through consideration of the anatomical composition of the vagus nerve, its physiology and its distribution throughout the body, we review the effects of vagus nerve stimulation in the context of drug-resistant epilepsy. This narrative review is divided into two sections: part one surveys the anatomy and physiology of the vagus nerve, and part two describes what we know about how vagus nerve stimulation works.

Vagus Nerve Stimulation in Stroke Management: Brief Review of Evolution and Present Applications Paired with Rehabilitation

Cerebrovascular accident (CVA) or stroke is a devastating neurological condition with dismal prognosis associated with recurrent episodes that further damage the neuronal networks, thus disabling neuronal plasticity. Vagus nerve stimulation (VNS) has been used in clinical practice to treat epilepsy for several decades and is well accepted as a safe procedure devoid of serious adverse events. Bailey and Bremer demonstrated that VNS has the capabilities to stimulate neuronal pathways that enhance the recovery of damaged cerebral function. Further studies have strengthened these observations, while technology has improved the tolerability of implants, resulting in VNS applications for epilepsy. Several animal models on neural plasticity have improved our understanding of VNS and its ability to provide neuromodulation to improve recovery in stroke patients. The closed-loop stimulation of the vagus nerve with individualized stimulation parameters combined with physical therapy appears to be an attractive option today. VNS is also being tested as a noninvasive trans-cutaneous modality to further improve patient acceptance and tolerability. However, the implantation of VNS is yielding desirable outcomes and appears to be a more reliable treatment for stroke rehabilitation in clinical trials.

Advancing Therapeutic Solutions for Burn Wounds: Potential Use of Noninvasive Ultrasound-Driven Splenic Stimulation

Significance: Burn wound injuries are a global health challenge, affecting millions annually and resulting in significant morbidity, mortality, and economic burden. The urgent need for accessible and cost-effective therapeutic alternatives, especially for underserved populations, has driven interest in novel approaches such as noninvasive splenic stimulation using pulsed-focused ultrasound (pFUS). This technique targets systemic inflammation, a key factor in delayed wound healing, offering a potential shift in burn care management. Recent Advances: Preclinical studies have shown that pFUS applied to the spleen can accelerate wound healing by activating the cholinergic anti-inflammatory pathway, promoting pro-angiogenic and anti-inflammatory responses. While current treatments-including biologics, antioxidants, and growth factors-have limitations, pFUS presents a noninvasive alternative. One interventional study and ongoing clinical trials are now investigating its application in burn wound care, marking an important step toward clinical translation. Critical Issues: Despite encouraging results, research on splenic stimulation for wound healing remains limited. The small number of studies highlights the need for further investigation into the underlying mechanisms, optimal treatment parameters, and potential risks. Additionally, the scalability and cost-effectiveness of pFUS in diverse clinical settings require thorough evaluation. Future Directions: Ongoing clinical trials will provide critical data on the efficacy and safety of splenic pFUS in burn patients. Future research should focus on expanding clinical studies, refining stimulation protocols, and exploring its broader application in tissue repair. If validated, this approach could offer a cost-effective, noninvasive treatment, particularly valuable in socioeconomically challenged regions.

Overcoming failure: improving acceptance and success of implanted neural interfaces

Implanted neural interfaces are electronic devices that stimulate or record from neurons with the purpose of improving the quality of life of people who suffer from neural injury or disease. Devices have been designed to interact with neurons throughout the body to treat a growing variety of conditions. The development and use of implanted neural interfaces is increasing steadily and has shown great success, with implants lasting for years to decades and improving the health and quality of life of many patient populations. Despite these successes, implanted neural interfaces face a multitude of challenges to remain effective for the lifetime of their users. The devices are comprised of several electronic and mechanical components that each may be susceptible to failure. Furthermore, implanted neural interfaces, like any foreign body, will evoke an immune response. The immune response will differ for implants in the central nervous system and peripheral nervous system, as well as over time, ultimately resulting in encapsulation of the device. This review describes the challenges faced by developers of neural interface systems, particularly devices already in use in humans. The mechanical and technological failure modes of each component of an implant system is described. The acute and chronic reactions to devices in the peripheral and central nervous system and how they affect system performance are depicted. Further, physical challenges such as micro and macro movements are reviewed. The clinical implications of device failures are summarized and a guide for determining the severity of complication was developed and provided. Common methods to diagnose and examine mechanical, technological, and biological failure modes at various stages of development and testing are outlined, with an emphasis on chronic in vivo characterization of implant systems. Finally, this review concludes with an overview of some of the innovative solutions developed to reduce or resolve the challenges faced by implanted neural interface systems.

Association between autoimmune disease and neurodevelopmental disorder: a Mendelian randomization analysis

INTRODUCTION

Neurodevelopmental disorders such as attention deficit and disruptive behaviour disorders (ADHD), autism spectrum disorder (ASD), and schizophrenia have been increasingly prevalent recently. Previous research has demonstrated that inflammatory activity from autoimmune diseases is involved in neurological diseases. However, some studies question the association between inflammatory activities and neurodevelopmental disorders. Herein, we attempt to clarify this relationship using Mendelian randomization (MR) analysis.

METHODS

We used systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and type 1 diabetes mellitus (T1D) to represent autoimmune diseases. First, we conducted MR analysis to examine associated SNPs between autoimmune and neurodevelopmental disorders. Second, we performed bidirectional MR analysis to identify 429 types of signalling peptides and proteins or relevant receptors with causality reported diseases. Finally, we compared the genes with the gene loci identified in the available TWAS-hub site.

RESULTS

The MR results of autoimmune diseases on neurodevelopmental disorders did not present any significant association in all models. However, we identified 20-45 factors in ADHD, ASD, and schizophrenia, including semaphorin 3, IL-27 receptor subunit alpha, and fibroblast growth factor 16, which were considered clinically significant pro-inflammatory mediators. GO and KEGG enrichment analyses revealed unequal integrities among the three neurodevelopmental diseases, and we failed to identify a shared pathway linking autoimmune diseases and neurodevelopmental disorders. TWAS analysis indicated that CHRNA5 potentially mediates inflammatory activities in schizophrenia.

CONCLUSION

According to our data, we failed to identify an association between autoimmune diseases and neurodevelopmental disorders. However, we demonstrated that some pro-inflammatory factors are involved in neurodevelopmental disorders.

Autonomic Nervous System in Bone Remodeling: From Mechanisms to Novel Therapies in Orthopedic Diseases

Recent literature has increasingly demonstrated the significant function of autonomic nerves in regulating physiological and pathological changes associated with the skeletal system. Extensive studies have been conducted to understand the contribution of the autonomic nervous system (ANS) to skeletal metabolic homeostasis and resistance to aseptic inflammation, specifically from the viewpoint of skeletal neurobiology. There have been plenty of studies on how the sympathetic nervous system (SNS) and parasympathetic nervous system (PNS), the two main branches of the ANS, regulate bone remodeling, which is the process of bone formation and resorption. The following studies have revealed critical neurological pathways that induce significant alterations in bone cell biology and uncover the intricate linkages between the ANS and the skeletal system. Furthermore, inspired by the connection between the ANS and bone remodeling, neuromodulation has been utilized as a therapeutic method for patients with orthopedic diseases: by directly influencing the ANS, it is possible to alter the excitability of nerve fibers and the release of neurotransmitters, which can lead to anti-inflammatory and analgesic effects, thereby directly or indirectly impacting bone formation and bone resorption. Our work aims to review the most recent findings on the impact of the ANS on bone remodeling, enhance the current understanding of the interaction between nerves and bones, and explore potential neuromodulation methods that could be used to treat orthopedic conditions, thereby drawing attention to the significant role of the ANS in the skeletal system.

Noninvasive Vagus Nerve Electrical Stimulation for Immune Modulation in Sepsis Therapy

Sepsis presents a significant medical challenge due to its intense inflammatory response to infection, often resulting in high mortality rates. A promising therapeutic strategy targets the cholinergic anti-inflammatory pathway (CAIP), which regulates immune responses. This study investigates the ingestion of piezoelectric particles that adhere to the stomach lining, specifically targeting TRPV1 receptors. In a mouse model of sepsis, these particles, when activated by low-intensity pulsed ultrasound, generate mild electrical pulses. These pulses stimulate vagal afferent fibers, transmitting signals to the brain and modulating the neural-immune network via the CAIP. Consequently, this leads to a reduction in systemic inflammation, mitigating weight loss, alleviating multiple tissue injuries, and preventing death by modulating immune cells in the spleen. This approach addresses the critical need for noninvasive sepsis therapies, potentially improving patient outcomes. Utilizing portable ultrasound equipment with minimal thermal effects, this technique offers a safe and convenient treatment option, even for home use.

Neuroimmune Interactions in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive primary malignancy, and recent technological advances in surgery have opened up more possibilities for surgical treatment. Emerging evidence highlights the critical roles of diverse immune and neural components in driving the aggressive behavior of PDAC. Recent studies have demonstrated that neural invasion, neural plasticity, and altered autonomic innervation contribute to pancreatic neuropathy in PDAC patients, while also elucidating the functional architecture of nerves innervating pancreatic draining lymph nodes. Research into the pathogenesis and therapeutic strategies for PDAC, particularly from the perspective of neuroimmune network interactions, represents a cutting-edge area of investigation. This review focuses on neuroimmune interactions, emphasizing the current understanding and future challenges in deciphering the reciprocal relationship between the nervous and immune systems in PDAC. Despite significant progress, key challenges remain, including the precise molecular mechanisms underlying neuroimmune crosstalk, the functional heterogeneity of neural and immune cell populations, and the development of targeted therapies that exploit these interactions. Understanding the molecular events governing pancreatic neuroimmune signaling axes will not only advance our knowledge of PDAC pathophysiology but also provide novel therapeutic targets. Translational efforts to bridge these findings into clinical applications, such as immunomodulatory therapies and neural-targeted interventions, hold promise for improving patient outcomes. This review underscores the need for further research to address unresolved questions and translate these insights into effective therapeutic strategies for PDAC.

Vagus nerve stimulation (VNS) preventing postoperative cognitive dysfunction (POCD): two potential mechanisms in cognitive function

Postoperative cognitive dysfunction (POCD) impacts a significant number of patients annually, frequently impairing their cognitive abilities and resulting in unfavorable clinical outcomes. Aimed at addressing cognitive impairment, vagus nerve stimulation (VNS) is a therapeutic approach, which was used in many mental disordered diseases, through the modulation of vagus nerve activity. In POCD model, the enhancement of cognition function provided by VNS was shown, demonstrating VNS effect on cognition in POCD. In the present study, we primarily concentrates on elucidating the role of the VNS improving the cognitive function in POCD, via two potential mechanisms: the inflammatory microenvironment and epigenetics. This study provided a theoretical support for the feasibility that VNS can be a potential method to enhance cognition function in POCD.

GTS-21 modulates rheumatoid arthritis Th17 and Th2 lymphocyte subset differentiation through the ɑ7nAch receptor

Previous research has demonstrated ɑ7nAch receptor (ɑ7nAchR) agonists to provide benefit for rheumatoid arthritis (RA) patients. However, the immunological mechanism of action for these ɑ7nAchR agonists has not been elucidated. Herein, the effect of GTS-21, a selective ɑ7nAchR agonist, on the differentiation of Th17 and Th2 cells was assessed. CD4 + T cells were obtained from the peripheral blood mononuclear cells (PBMCs) of RA patients and healthy donors. CD4 + T cells were separately differentiated into Th2 or Th17 cells with or without GTS-21 and with or without alpha-bungarotoxin (ɑBgt) (a ɑ7nAchR antagonist). The proportions of Th17 and Th2 cells were assessed by flow cytometry. Levels of the T cell cytokines, IL-17A and IL-4, were assessed by ELISA. Specific transcription factors, retinoic orphan receptor c (RORc), and GATA Binding Protein 3 (GATA-3) were detected by western blot. GTS-21 reduced IL-17A and increased IL-4 production by RA PBMCs. GTS-21 reduced the percentage of Th17 cells and increased the percentage of Th2 cells during Th17 and Th2 differentiation, respectively. GTS-21 downregulated RA CD4 + T cells RORc levels and reduced the secretion of IL-17A during Th17 differentiation. GTS-21 upregulated RA CD4 + T cells GATA3 and promoted IL-4 production during Th2 differentiation. ɑ-Bgt blocked the effects of GTS-21 during Th17 and Th2 differentiation. These results demonstrated that GTS-21 suppressed RA Th17 differentiation and promoted Th2 differentiation. As such, the use of GTS-21 may be a new therapeutic approach by which to treat RA patients. Key Points • GTS-21 suppressed RA Th17 differentiation and promoted Th2 differentiation via acting on ɑ7nAchR. • The protective effect of GTS-21 on RA may be related to its regulation of Th cell subsets.

Clinical neurocardiology: defining the value of neuroscience-based cardiovascular therapeutics - 2024 update

The intricate role of the autonomic nervous system (ANS) in regulating cardiac physiology has long been recognized. Aberrant function of the ANS is central to the pathophysiology of cardiovascular diseases. It stands to reason, therefore, that neuroscience-based cardiovascular therapeutics hold great promise in the treatment of cardiovascular diseases in humans. A decade after the inaugural edition, this White Paper reviews the current state of understanding of human cardiac neuroanatomy, neurophysiology and pathophysiology in specific disease conditions, autonomic testing, risk stratification, and neuromodulatory strategies to mitigate the progression of cardiovascular diseases.

Phosphotungstic Acid Staining to Visualize the Vagus Nerve Perineurium Using Micro-CT

BACKGROUND AND PURPOSE

Peripheral nerve stimulation is approved by the US Food and Drug Administration for treating various disorders, but it is often limited by side effects, highlighting the need for a clear understanding of fascicular and fiber organization to design selective therapies. Micro-CT imaging of contrast-stained nerves enables the visualization of tissue microstructures, such as the fascicular perineurium and vasculature. In this work, we evaluated phosphotungstic acid (PTA) as a contrast agent and assessed its compatibility with downstream histology.

METHODS

Human vagus nerve samples were collected from three embalmed cadavers and subjected to three different staining methods, followed by micro-CT imaging: Lugol's iodine, osmium tetroxide, and PTA. Contrast ratios of adjacent tissue microstructures (perineurium, interfascicular epineurium, and fascicle) were quantified for each stain and compared. We further developed a pipeline to optimize micro-CT scan acquisition parameters based on objective metrics for sharpness, noise, and pixel saturation. The PTA-stained samples underwent subsequent histological processing and staining with hematoxylin and eosin, Masson's trichrome, and immunohistochemistry and were assessed for tissue degradation.

RESULTS

PTA enhanced the visualization of perineurium, providing high contrast ratios compared to iodine and osmium tetroxide. Optimized scanning parameters for PTA-stained nerves (55 kV and 109 µA) effectively balanced noise and sharpness. While we found that PTA is generally nondestructive for downstream histology, higher concentrations and longer exposure could alter the optical density of nuclei and affect stain differentiation in special stains.

CONCLUSION

PTA serves as a valuable micro-CT contrast agent for nerve imaging, effective in visualizing the perineurium with minimal impact on histological integrity.

Mechanism and Applications of Vagus Nerve Stimulation

Over the past three decades, vagus nerve stimulation (VNS) has emerged as a promising rehabilitation therapy for a diverse range of conditions, demonstrating substantial clinical potential. This review summarizes the in vivo biological mechanisms activated by VNS and their corresponding clinical applications. Furthermore, it outlines the selection of parameters and equipment for VNS implementation. VNS exhibits anti-inflammatory effects, modulates neurotransmitter release, enhances neural plasticity, inhibits apoptosis and autophagy, maintains blood-brain barrier integrity, and promotes angiogenesis. Clinically, VNS has been utilized in the treatment of epilepsy, depression, headache, stroke, and obesity. Its potential applications extend to anti-inflammatory treatment and the management of cardiovascular and cerebrovascular diseases and various brain disorders. However, further experiments are required to definitively establish the efficacy of VNS's various mechanisms. Additionally, there is a need to explore and identify optimal rehabilitation treatment parameters for different diseases.

Characterization of motor nerve stimulation using sinusoidal low frequency alternating currents and cuff electrodes

Objective:Direct electrical neurostimulation using continuous sinusoidal low frequency alternating currents (LFAC) is an emerging modality for neuromodulation. As opposed to the traditional rectangular pulse stimulation, there is limited background on the characteristics of peripheral nerves responses to sinusoidal LFAC stimulation; especially within the low frequency range (<50 Hz). In this study, we demonstrate LFAC activation as a means to activate motor nerves by direct bipolar nerve stimulation via cuff electrodes, and characterize the factors of activation. We study and quantify the effects of sinusoidal frequency and electrode geometry on the motor nerve activation thresholdin-vivoand in computational models,in-silico.Approach:Acutein-vivoexperiments (N= 34) were conducted on isoflurane-anaesthetized rats. A pure tone continuous sinusoidal current was applied to the rat sciatic nerve in bipolar configurations via bipolar or tripolar nerve cuff electrodes (different contact separations). LFAC activation thresholds were quantified by measuring the electromyogram (EMG) response of the triceps surae muscles and the induced twitch force to LFAC stimulation at six frequencies (1, 2, 3, 4, 8, and 20 Hz). Computationally, we utilized a volume conductor model of a bipolar cuff electrode around a single rat-size fascicle and projected the potentials to the McIntyre-Richardson-Grill models of myelinated motor nerve fibers. We compared thein-silicoresponses of a range of fiber diameters (5.7 to 16µm) to LFAC stimulation and their activation thresholds to thein-vivofindings.Main results: Sinusoidal LFAC stimulation elicited motor nerve activityin-vivoandin-silico, with a remarkable convergence of thein-silicopredictions to thein-vivoobservations. The EMG activity showed that muscle responses to LFAC stimulation were phase-locked to the sinusoidal cycle but exhibited two distinct activation modes. These modes were classified as burst and unitary, indicating the presence of two distinct patterns of muscle activation during LFAC stimulation. The LFAC motor activation threshold was significantly dependent on frequency and influenced by the contact separation of the cuff electrode, with a greater extent of reduction at a higher frequency or wider separation. Moreover, the order of fiber recruitment was suggested to be normal-physiological (small-to-large caliber) given the nature of the induced EMG activity andin-silicopredictions.Significance: These findings provide significant insights into the nature of sinusoidal LFAC stimulation, at the explored range of frequency, and the expected mammalian peripheral motor nerve responses to LFAC. The characteristics of sinusoidal LFAC stimulation would facilitate selectivity approaches in a broader range of therapeutic and rehabilitative neuromodulation applications.

Assessing the therapeutic potential of vagus nerve stimulation in autoimmune diseases: A systematic review

Emerging evidence suggests that the vagus nerve can modulate the immune system in experimental settings. Vagus nerve stimulation (VNS), initially developed for managing epilepsy, is now being explored as a treatment for autoimmune diseases due to its potential immunomodulatory effects. This systematic review evaluates the therapeutic potential of VNS in autoimmune diseases by critically appraising findings from human clinical studies. This systematic review was conducted in accordance with the PRISMA guideline, with a comprehensive literature search performed in Ovid, Cochrane, and PubMed databases up to July 2024. Studies focusing on VNS in patients with autoimmune diseases were eligible, and the quality of study was assessed using the QualSyst tool. Of the 53 papers identified for full-text assessment, 19 studies met the eligibility criteria. Findings suggest that VNS is a promising adjunctive therapy for Crohn's disease and rheumatoid arthritis, showing potential to alleviate symptoms and modulate immune responses. The efficacy and safety of VNS vary widely across studies, highlighting the complex nature of autoimmune diseases and the diverse mechanisms of VNS action. Future research should prioritize large-scale, randomized controlled trials with standardized protocols to further elucidate the efficacy, long-term safety, and optimal parameters of VNS across various autoimmune conditions.

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.

Transcutaneous vagus nerve stimulation as a pain modulator in knee osteoarthritis: a randomized controlled clinical trial

BACKGROUND

Our understanding of osteoarthritis (OA) has evolved from a degenerative disease to one in which low-grade, chronic inflammation plays a central role. In addition, evidence suggests that OA is accompanied by both peripheral and central nervous system sensitization that can cause pain. It has been demonstrated that transcutaneous vagus nerve stimulation (tVNS) can relieve pain, inflammation, and central sensitization in other conditions including fibromyalgia, pelvic pain, and headaches. We aimed to assess the efficacy and safety of tVNS on nociceptive pain, central sensitization, and physical function in knee OA.

METHODS

In this 12-week study, we stimulated the auricular branch of the vagus nerve with an auricular electrode connected to a transcutaneous electrical nerve stimulation device once a day for 3 days each week for 12 weeks. A total of 68 patients with chronic knee OA were randomly assigned to the active and sham groups (34 patients in each group). We used a variety of outcome measures, including the visual analog scale (VAS), pressure pain threshold (PPT), knee injury and osteoarthritis outcome score (KOOS), PainDETECT (PD-Q) and Douleur Neuropathique 4 (DN4) questionnaires. Outcome measures were recorded at baseline, At the end of the stimulation period, and then after 4 weeks.

RESULTS

In the active group, compared to baseline, there was a significant improvement in VAS scores between the first and second follow-up visits (P < 0.001). A significant improvement in PPT was seen in the right knee, left knee, and right elbow in active tVNS, and this improvement persisted for four weeks post-intervention. Meanwhile, in the sham group, right knee PPT was improved but not maintained. There were statistically significant improvements in the PD-Q and DN4 scores in the active tVNS group (P < 0.001), whereas in the sham group, DN4 questionnaire did not show any improvement. In terms of functional outcomes, the improvement in KOOS was significant only in the active group (31.44 ± 18.49, P < 0.001). No serious adverse events were observed.

CONCLUSION

There is preliminary evidence to support the benefits of tVNS in OA, suggesting that neuromodulation can be used as an adjunct to existing pharmacological and non-pharmacological treatments.

TRIAL REGISTRATION

The study was registered on ClinicalTrials.gov (NCT05387135) on 24/05/2022.

Mechanisms of vagus nerve stimulation for the treatment of neurodevelopmental disorders: a focus on microglia and neuroinflammation

The vagus nerve (VN) is the primary parasympathetic nerve, providing two-way communication between the body and brain through a network of afferent and efferent fibers. Evidence suggests that altered VN signaling is linked to changes in the neuroimmune system, including microglia. Dysfunction of microglia, the resident innate immune cells of the brain, is associated with various neurodevelopmental disorders, including schizophrenia, attention deficit hyperactive disorder (ADHD), autism spectrum disorder (ASD), and epilepsy. While the mechanistic understanding linking the VN, microglia, and neurodevelopmental disorders remains incomplete, vagus nerve stimulation (VNS) may provide a better understanding of the VN's mechanisms and act as a possible treatment modality. In this review we examine the VN's important role in modulating the immune system through the inflammatory reflex, which involves the cholinergic anti-inflammatory pathway, which releases acetylcholine. Within the central nervous system (CNS), the direct release of acetylcholine can also be triggered by VNS. Homeostatic balance in the CNS is notably maintained by microglia. Microglia facilitate neurogenesis, oligodendrogenesis, and astrogenesis, and promote neuronal survival via trophic factor release. These cells also monitor the CNS microenvironment through a complex sensome, including groups of receptors and proteins enabling microglia to modify neuroimmune health and CNS neurochemistry. Given the limitations of pharmacological interventions for the treatment of neurodevelopmental disorders, this review seeks to explore the application of VNS as an intervention for neurodevelopmental conditions. Accordingly, we review the established mechanisms of VNS action, e.g., modulation of microglia and various neurotransmitter pathways, as well as emerging preclinical and clinical evidence supporting VNS's impact on symptoms associated with neurodevelopmental disorders, such as those related to CNS inflammation induced by infections. We also discuss the potential of adapting non-invasive VNS for the prevention and treatment of these conditions. Overall, this review is intended to increase the understanding of VN's potential for alleviating microglial dysfunction involved in schizophrenia, ADHD, ASD, and epilepsy. Additionally, we aim to reveal new concepts in the field of CNS inflammation and microglia, which could serve to understand the mechanisms of VNS in the development of new therapies for neurodevelopmental disorders.

Bioelectronic Medicines-A Novel Approach of Therapeutics in Current Epoch

BACKGROUND

Bioelectronic medicines aim to diagnose and treat a wide range of illnesses and ailments, including cancer, rheumatoid arthritis, inflammatory bowel disease, obesity, diabetes, asthma, paralysis, blindness, bleeding, ischemia, organ transplantation, cardiovascular disease, and neurodegenerative diseases. The focus of bioelectronic medicine is on electrical signaling of the nervous system. Understanding the nervous system's regulatory roles and developing technologies that record, activate, or inhibit neural signaling to influence particular biological pathways.

OBJECTIVE

Bioelectronic medicine is an emerging therapeutic option with the interconnection between molecular medicine, neuroscience, and bioengineering. The creation of nerve stimulating devices that communicate with both the central and peripheral nervous systems has the potential to completely transform how we treat disorders. Although early clinical applications have been largely effective across entire nerves, the ultimate goal is to create implantable, miniature closed-loop systems that can precisely identify and modulate individual nerve fibers to treat a wide range of disorders.

METHODOLOGY

The data bases such as PubMed, and Clinicaltrial.gov.in were searched for scientific research, review and clinical trials on bioelectronic medicine.

CONCLUSION

The field of bioelectronic medicine is trending at present. In recent years, researchers have extended the field's applications, undertaken promising clinical trials, and begun delivering therapies to patients, thus creating the groundwork for significant future advancements. Countries and organizations must collaborate across industries and regions to establish an atmosphere and guidelines that foster the advancement of the field and the fulfillment of its prospective advantages.

The Case for Neurosurgical Intervention in Cancer Neuroscience

The emerging field of cancer neuroscience reshapes our understanding of the intricate relationship between the nervous system and cancer biology; this new paradigm is likely to fundamentally change and advance neuro-oncological care. The profound interplay between cancers and the nervous system is reciprocal: Cancer growth can be induced and regulated by the nervous system; conversely, tumors can themselves alter the nervous system. Such crosstalk between cancer cells and the nervous system is evident in both the peripheral and central nervous systems. Recent advances have uncovered numerous direct neuron-cancer interactions at glioma-neuronal synapses, paracrine mechanisms within the tumor microenvironment, and indirect neuroimmune interactions. Neurosurgeons have historically played a central role in neuro-oncological care, and as the field of cancer neuroscience is becoming increasingly established, the role of neurosurgical intervention is becoming clearer. Examples include peripheral denervation procedures, delineation of neuron-glioma networks, development of neuroprostheses, neuromodulatory procedures, and advanced local delivery systems. The present review seeks to highlight key cancer neuroscience mechanisms with neurosurgical implications and outline the future role of neurosurgical intervention in cancer neuroscience.

A Mechanistic Analysis of the Neural Modulation of the Inflammatory System Through Vagus Nerve Stimulation: A Systematic Review and Meta-analysis

OBJECTIVE

We aimed to conduct a systematic review and meta-analysis assessing the antiinflammatory effects of various VNS methods while exploring multiple antiinflammatory pathways.

MATERIALS AND METHODS

We included clinical trials that used electrical stimulation of the vagus nerve and assessed inflammatory markers up to October 2022. We excluded studies lacking control groups, those with combined interventions, or abstracts without full text. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and the Cochrane Handbook for Systematic Reviews. For each inflammatory marker, a random-effects meta-analysis using the inverse variance method was performed. Methods used include transcutaneous auricular VNS (taVNS), transcutaneous cervical VNS (tcVNS), invasive cervical VNS (iVNS), and electroacupuncture VNS (eaVNS). Main reported outcomes included tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1ß, C-reactive protein (CRP), and IL-10. Risk of bias was evaluated using the Cochrane Collaboration Tool (RoB 2.0).

RESULTS

This review included 15 studies, involving 597 patients. No statistically significant general VNS effect was observed on TNF-α, IL-6, and IL-1ß. However, CRP, IL-10, and interferon (IFN)-γ were significantly modulated by VNS across all methods. Subgroup analysis revealed specific stimulation techniques producing significant results, such as taVNS effects in IL-1ß and IL-10, and iVNS in IL-6, whereas tcVNS and eaVNS did not convey significant pooled results individually. Cumulative exposure to VNS, higher risk of bias, study design, and pulse width were identified as effect size predictors in our meta-regression models.

CONCLUSIONS

Pooling all VNS techniques indicated the ability of VNS to modulate inflammatory markers such as CRP, IL-10, and IFN-γ. Individually, methods such as taVNS were effective in modulating IL-1ß and IL-10, whereas iVNS modulated IL-6. However, different VNS techniques should be separately analyzed in larger, homogeneous, and powerful studies to achieve a clearer and more consistent understanding of the effect of each VNS method on the inflammatory system.

The mechanisms of electrical neuromodulation

The central and peripheral nervous systems are specialized to conduct electrical currents that underlie behaviour. When this multidimensional electrical system is disrupted by degeneration, damage, or disuse, externally applied electrical currents may act to modulate neural structures and provide therapeutic benefit. The administration of electrical stimulation can exert precise and multi-faceted effects at cellular, circuit and systems levels to restore or enhance the functionality of the central nervous system by providing an access route to target specific cells, fibres of passage, neurotransmitter systems, and/or afferent/efferent communication to enable positive changes in behaviour. Here we examine the neural mechanisms that are thought to underlie the therapeutic effects seen with current neuromodulation technologies. To gain further insights into the mechanisms associated with electrical stimulation, we summarize recent findings from genetic dissection studies conducted in animal models. KEY POINTS: Electricity is everywhere around us and is essential for how our nerves communicate within our bodies. When nerves are damaged or not working properly, using exogenous electricity can help improve their function at distinct levels - inside individual cells, within neural circuits, and across entire systems. This method can be tailored to target specific types of cells, nerve fibres, neurotransmitters and communication pathways, offering significant therapeutic potential. This overview explains how exogenous electricity affects nerve function and its potential benefits, based on research in animal studies. Understanding these effects is important because electrical neuromodulation plays a key role in medical treatments for neurological conditions.

The Impact of Autonomic Nervous System Modulation on Heart Rate Variability and Musculoskeletal Manifestations in Chronic Neck Pain: A Double-Blind Randomized Clinical Trial

Background: The role of autonomic nervous system (ANS) modulation in chronic neck pain remains elusive. Transcutaneous vagus nerve stimulation (t-VNS) provides a novel, non-invasive means of potentially mitigating chronic neck pain. This study aimed to assess the effects of ANS modulation on heart rate variability (HRV), pain perception, and neck disability. Methods: In this double-blind randomized clinical trial, 102 participants with chronic neck pain were randomly allocated to one of three groups: t-VNS plus standard-care physiotherapy (SC-PT), heart rate variability biofeedback (HRV-BF) with SC-PT, or SC-PT alone. Interventions were administered three times weekly for 6 weeks. The following outcome measures were assessed at baseline and after 6 weeks: HRV, the visual analog scale (VAS), the pressure pain threshold (PPT), and the neck disability index (NDI). Results: The t-VNS group exhibited significant improvements compared to the HRV-BF and SC-PT groups. Specifically, t-VNS increased the RR interval (mean difference [MD] = 35.0 ms; p = 0.037) and decreased the average heart rate (MD = -5.4 bpm; p = 0.039). Additionally, t-VNS reduced the VAS scores (versus HRV-BF: MD = -0.8 cm, p = 0.044; SC-PT: MD = -0.9 cm, p = 0.018), increased the PPT (versus HRV-BF: MD = 94.4 kPa, p < 0.001; SC-PT (MD = 56.2 kPa, p = 0.001)), and lowered the NDI scores (versus HRV-BF: MD = -4.0, p = 0.015; SC-PT: MD = -5.9, p < 0.001). Conclusions: t-VNS demonstrated superior effectiveness compared to HRV-BF and SC-PT in regulating HRV, alleviating pain, and enhancing functional capabilities in individuals with chronic neck pain.

Facing stress and inflammation: From the cell to the planet

As identified in 1936 by Hans Selye, stress is shaping diseases through the induction of inflammation. But inflammation display some yin yang properties. On one hand inflammation is merging with the innate immune response aimed to fight infectious or sterile insults, on the other hand inflammation favors chronic physical or psychological disorders. Nature has equipped the cells, the organs, and the individuals with mediators and mechanisms that allow them to deal with stress, and even a good stress (eustress) has been associated with homeostasis. Likewise, societies and the planet are exposed to stressful settings, but wars and global warming suggest that the regulatory mechanisms are poorly efficient. In this review we list some inducers of the physiological stress, psychologic stress, societal stress, and planetary stress, and mention some of the great number of parameters which affect and modulate the response to stress and render it different from an individual to another, from the cellular level to the societal one. The cell, the organ, the individual, the society, and the planet share many stressors of which the consequences are extremely interconnected ending in the domino effect and the butterfly effect.

Electroceuticals: Unlocking the promise of therapies

OBJECTIVES

Electroceuticals refers to the constantly growing disciplines of bioelectric and bioelectronic medication. These include a broad variety of devices that have been invented and are now being utilized in medical implants, wearable medical electronics, and bioelectronics. The primary aim of this study is to encompass several facets of electroceuticals, their applications, and recent advancements in the field of medical challenges.

EVIDENCE ACQUISITIONS

A complete literature study was conducted, which included a comprehensive review of globally recognized scientific research databases.

RESULTS

The progressive refinement and diminution of technology, in conjunction with swift advancements in comprehending the role of electrical pathways in the human body, have rendered it progressively viable to manipulate these pathways for therapeutic purposes.

DISCUSSION AND CONCLUSION

Electrical stimulation impacts and modifies biological functioning and pathological processes in the body. In the contemporary era of medicine, health care practitioners from a variety of fields utilize electricity to cure disease or injury or to assess and diagnose using a variety of electrically driven medical tools.

Electrostimulation suppresses allograft rejection via promoting lymphatic regulatory T cell migration mediated by lymphotoxin - lymphotoxin receptor β signaling

Conventional immunosuppressants that suppress allograft rejection cause various side effects. Although regulatory T cells (Tregs) are essential for allograft survival, the limited efficacy of Treg therapy demands improvement. Thus, it is imperative to seek new approaches to enhancing Treg suppression. Low-intensity electrostimulation (ES) has been shown to exert antiinflammatory effects without causing major adverse reactions. However, it remains unknown whether and how ES regulates alloimmunity. Here, we found that regional ES delayed murine skin allograft rejection and promoted long-term allograft survival induced by an mTOR inhibitor, rapamycin. ES also extended islet allograft survival. Mechanistically, ES enhanced the expression of lymphotoxin α (LTα) on Tregs after transplantation. Blockade of lymphotoxin β receptor-mediated nonclassical NFκB signaling suppressed lymphatic Treg migration and largely reversed the effects of ES on allograft survival. Moreover, ES failed to extend allograft survival when recipients lacked LTα/lymph nodes or if transferred Tregs lacked LTα. Therefore, ES promoted the lymphatic migration of CD4+Foxp3+ Tregs by upregulating their surface expression of LTα. Finally, ES augmented expression of LTα on murine or human Tregs, but not conventional T cells, while promoting their calcium influx in vitro. This ES-mediated upregulation of LTα relied on calcium influx. Thus, our findings have unveiled novel mechanisms underlying ES-mediated immunoregulation.

Effect of Neurostimulation on Chronic Pancreatic Pain: A Systematic Review

BACKGROUND

Chronic pancreatic pain is one of the most severe causes of visceral pain, and treatment response is often limited. Neurostimulation techniques have been investigated for chronic pain syndromes once there are pathophysiological reasons to believe that these methods activate descending pain inhibitory systems. Considering this, we designed this systematic literature review to investigate the evidence on neuromodulation techniques as a treatment for chronic pancreatic pain.

MATERIALS AND METHODS

We performed a literature search using the databases MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), and Embase until April 2024. The included studies used neurostimulation techniques in participants with chronic pancreatic pain and reported pain-related outcomes, with a focus on pain scales and opioid intake. Two reviewers screened and extracted data, and a third reviewer resolved discrepancies. We assessed the risk of bias using the Jadad scale. The authors then grouped the findings by the target of the neurostimulation, cortex, spinal cord, or peripheral nerves; described the findings qualitatively in the results section, including qualitative data reported by the articles; and calculated effect sizes of pain-related outcomes.

RESULTS

A total of 22 studies were included (7 randomized clinical trials [RCTs], 14 case series, and 1 survey), including a total of 257 clinical trial participants. The two outcomes most commonly reported were pain, measured by the visual analogue scale (VAS), numeric rating scale (NRS), and pressure pain threshold scores, and opioid intake. Two RCTs investigated repetitive transcranial magnetic stimulation (rTMS), showing a reduction of 36% (±16) (d = 2.25; 95% CI, 0.66-3.83) and 27.2% (±24.5%) (d = 2.594; 95% CI, 1.303-3.885) in VAS pain scale. In another clinical trial, transcranial direct-current stimulation (tDCS) and transcranial pulsed current stimulation were not observed to effect a significant reduction in VAS pain (χ2 = 5.87; p = 0.12). However, a complete remission was reported in one tDCS case. Spinal cord stimulation (SCS) and dorsal root ganglion stimulation were performed in a survey and 11 case series, showing major pain decrease and diminished opioid use in 90% of participants after successful implantation; most studies had follow-up periods of months to years. Two noninvasive vagal nerve stimulation (VNS) RCTs showed no significant pain reduction in pain thresholds or VAS (d = 0.916; 95% CI, -0.005 to 1.838; and d = 0.17; -0.86 to 1.20; p = 0.72; respectively). Splanchnic nerve stimulation in one case report showed complete pain reduction accompanied by discontinuation of oral morphine and fentanyl lozenges and a 95% decrease in fentanyl patch use. Two RCTs investigated transcutaneous electrical nerve stimulation (TENS). One found a significant pain reduction effect with the NRS (d = 1.481; 95% CI, 1.82-1.143), and decreased opioid use, while the other RCT did not show significant benefit. Additionally, one case report with TENS showed pain improvement that was not quantitatively measured.

DISCUSSION

The neuromodulation techniques of rTMS and SCS showed the most consistent potential as a treatment method for chronic pancreatic pain. However, the studies have notable limitations, and SCS has had no clinical trials. For VNS, we have two RCTs that showed a non-statistically significant improvement; we believe that both studies had a lack of power issue and suggest a gap in the literature for new RCTs exploring this modality. Additionally, tDCS and TENS showed mixed results. Another important insight was that opioid intake decrease is a common trend among most studies included and that adverse effects were rarely reported. To further elucidate the potential of these neurostimulation techniques, we suggest the development of new clinical trials with larger samples and adequate sham controls.

Vagus nerve stimulation: Novel concept for the treatment of glioblastoma and solid cancers by cytokine (interleukin-6) reduction, attenuating the SASP, enhancing tumor immunity

Immuno-oncology, specifically immune checkpoint inhibitors (ICIs), has revolutionized cancer care with dramatic, long-term responses and increased survival, including patients with metastatic cancer to the brain. Glioblastomas, and other primary brain tumors, are refractory to ICIs as monotherapy or in combination with standard therapy. The tumor microenvironment (TME) poses multiple biological hurdles: blood-brain barrier, immune suppression, heterogeneity, and tumor infiltration. Genomic analysis of the senescence-associated secretory phenotype (SASP) and preclinical models of glioma suggest that an exciting approach would entail reprogramming of the glioma microenvironment, attenuating the pro-inflammatory, pro-tumorigenic cytokines of the SASP, especially interleukin-6 (IL-6). A testable hypothesis now proposed is to modulate the immune system by harnessing the body's 'inflammatory reflex' to reduce cytokines. Vagus nerve stimulation can activate T cell immunity by the cholinergic, α7nicotinic acetylcholine receptor agonist (α7nAchR), and suppress IL-6 systemically, as well as other pro-inflammatory cytokines of the SASP, interleukin -1β (IL-1β) and tumor necrosis factor-alpha (TNF-α). The hypothesis predicts that electrical activation of the vagus nerve, with cytokine reduction, in combination with ICIs, would convert an immune resistant ("cold") tumor to an immune responsive ("hot") tumor, and halt glioma progression. The hypothesis also envisions cancer as an immune "dysautonomia" whereby a therapeutic intervention, vagus nerve stimulation (VNS), resets the systemic and local cytokine levels. A prospective, randomized, phase II clinical trial, to confirm the hypothesis, is a logical, exigent, next step. Cytokine reduction by VNS could also be useful for other forms of human cancer, e.g., breast, colorectal, head and neck, lung, melanoma, ovarian, pancreatic, and prostate cancer, as the emerging field of "cancer neuroscience" shows a role for neural regulation of multiple tumor types. Because IL-6, and companion pro-inflammatory cytokines, participate in the initiation, progression, spread and recurrence of cancer, minimally invasive VNS could be employed to suppress glioma or cancer progression, while also mitigating depression and/or seizures, thereby enhancing quality of life. The current hypothesis reimagines glioma pathophysiology as a dysautonomia with the therapeutic objective to reset the autonomic nervous system and form an immune responsive state to halt tumor progression and prevent recurrence. VNS, as a novel method to control cancer, can be administered with ICIs, standard therapy, or in clinical trials, combined with emerging immunotherapy: dendritic cell, mRNA, or chimeric antigen receptor (CAR) T cell vaccines.

Vagus nerve stimulation (VNS): recent advances and future directions

PURPOSE

Vagus nerve stimulation (VNS) is emerging as a unique and potent intervention, particularly within neurology and psychiatry. The clinical value of VNS continues to grow, while the development of noninvasive options promises to change a landscape that is already quickly evolving. In this review, we highlight recent progress in the field and offer readers a glimpse of the future for this bright and promising modality.

METHODS

We compiled a narrative review of VNS literature using PubMed and organized the discussion by disease states with approved indications (epilepsy, depression, obesity, post-stroke motor rehabilitation, headache), followed by a section highlighting novel, exploratory areas of VNS research. In each section, we summarized the current role, recent advancements, and future directions of VNS in the treatment of each disease.

RESULTS

The field continues to gain appreciation for the clinical potential of this modality. VNS was initially developed for treatment-resistant epilepsy, with the first depression studies following shortly thereafter. Overall, VNS has gained approval or clearance in the treatment of medication-refractory epilepsy, treatment-resistant depression, obesity, migraine/cluster headache, and post-stroke motor rehabilitation.

CONCLUSION

Noninvasive VNS represents an opportunity to bridge the translational gap between preclinical and clinical paradigms and may offer the same therapeutic potential as invasive VNS. Further investigation into how VNS parameters modulate behavior and biology, as well as how to translate noninvasive options into the clinical arena, are crucial next steps for researchers and clinicians studying VNS.

Electrical vagus nerve stimulation is a promising approach to reducing pulmonary complications after an esophagectomy: an experimental rodent model

After esophagectomy, an imbalanced inflammatory response increases the risk of postoperative morbidity. The vagus nerve modulates local and systemic inflammatory responses, but its pulmonary branches are transected during esophagectomy as part of the oncological resection, which may account for the high incidence of postoperative (pulmonary) complications. This study investigated the effect of electrical vagus nerve stimulation (VNS) on lipopolysaccharide (LPS)-induced lung injury in rats. Rats (n = 60) were randomly assigned to a non-vagotomy or cervical vagotomy group, with VNS or without (NOSTIM). There were four non-vagotomy groups: NOSTIM and bilateral VNS with 100, 50, or 10 µA. The four vagotomy groups were NOSTIM and VNS with fixed amplitude (50 µA) bilaterally before (VNS-50-before) or after bilateral vagotomy (VNS-50-after), or unilaterally (left) before ipsilateral vagotomy (VNS-50-unilaterally). LPS was administered intratracheally after surgery. Pulmonary function, pro-inflammatory cytokines in serum, broncho-alveolar lavage fluid (BALF), and histopathological lung injury (LIS) were assessed 180 min post-procedure. In non-vagotomized rats, neutrophil influx in BALF following intra-tracheal LPS (mean 30 [± 23]; P = 0.075) and LIS (mean 0.342 [± 0.067]; P = 0.142) were similar after VNS-100, compared with NOSTIM. VNS-50 reduced neutrophil influx (23 [± 19]; P = 0.024) and LIS (0.316 [± 0.093]; P = 0.043). VNS-10 reduced neutrophil influx (15 [± 6]; P = 0.009), while LIS (0.331 [± 0.053]; P = 0.088) was similar. In vagotomized rats, neutrophil influx (52 [± 37]; P = 0.818) and LIS (0.407 [SD ± 0.037]; P = 0.895) in VNS-50-before were similar compared with NOSTIM, as well as in VNS-50-after (neutrophils 30 [± 26]; P = 0.090 and LIS 0.344 [± 0.053]; P = 0.073). In contrast, VNS-50-unilaterally reduced neutrophil influx (26 [± 10]; P = 0.050) and LIS (0.296 [± 0.065]; P = 0.005). Systemic levels of cytokines TNF-α and IL-6 were undetectable in all groups. Pulmonary function was not statistically significantly affected. In conclusion, VNS limited influx of neutrophils in lungs in non-vagotomized rats and may attenuate LIS. Unilateral VNS attenuated lung injury even after ipsilateral vagotomy. This effect was absent for bilateral VNS before and after bilateral vagotomy. It is suggested that the effect of VNS is dependent on (partially) intact vagus nerves and that the level of the vagotomy during esophagectomy may influence postoperative pulmonary outcomes.

Autonomic function and change in functional capacity in older adults: a longitudinal investigation

Functional capacity is an important objective health metric, and relies on the maintenance of physiological homeostasis. Autonomic nervous system is known to coordinates the maintenance of multi-organ homeostasis. The objective of this study was to examine the association of autonomic nervous system function with functional capacity in adults aged 55 years and older. A cohort of 542 adults (mean age of 70.1 years) received repeated measurements of heart rate variability, an autonomic nervous system function marker, and chair rise time, a functional capacity measure. Linear mixed models analysis showed that 1 SD lower powers in low-frequency range at baseline was associated with a 0.11 (95% CI 0.01-0.21) s/year faster increase in chair rise time during the follow-up, whereas 1 SD increase in powers in high-frequency range and 1 SD decrease in the ratio of powers in low-frequency range to powers in high-frequency range during the follow-up were associated with a 0.22 (95% CI 0.06-0.39) s and 0.17 (95% CI 0.01-0.33) s increase in chair rise time. In conclusion, autonomic nervous system function and its changes were longitudinally associated with changes in functional capacity in older adults.

Vagal stimulation ameliorates murine colitis by regulating SUMOylation

Inflammatory bowel diseases (IBDs) are chronic debilitating conditions without cure, the etiologies of which are unknown, that shorten the lifespans of 7 million patients worldwide by nearly 10%. Here, we found that decreased autonomic parasympathetic tone resulted in increased IBD susceptibility and mortality in mouse models of disease. Conversely, vagal stimulation restored neuromodulation and ameliorated colitis by inhibiting the posttranslational modification SUMOylation through a mechanism independent of the canonical interleukin-10/α7 nicotinic cholinergic vagal pathway. Colonic biopsies from patients with IBDs and mouse models showed an increase in small ubiquitin-like modifier (SUMO)2 and SUMO3 during active disease. In global genetic knockout mouse models, the deletion of Sumo3 protected against development of colitis and delayed onset of disease, whereas deletion of Sumo1 halted the progression of colitis. Bone marrow transplants from Sumo1-knockout (KO) but not Sumo3-KO mice into wild-type mice conferred protection against development of colitis. Electric stimulation of the cervical vagus nerve before the induction of colitis inhibited SUMOylation and delayed the onset of colitis in Sumo1-KO mice and resulted in milder symptoms in Sumo3-KO mice. Treatment with TAK-981, a first-in-class inhibitor of the SUMO-activating enzyme, ameliorated disease in three murine models of IBD and reduced intestinal permeability and bacterial translocation in a severe model of the disease, suggesting the potential to reduce progression to sepsis. These results reveal a pathway of vagal neuromodulation that reprograms endogenous stress-adaptive responses through inhibition of SUMOylation and suggest SUMOylation as a therapeutic target for IBD.

Non-invasive vagus nerve stimulation in anti-inflammatory therapy: mechanistic insights and future perspectives

Non-invasive vagus nerve stimulation (VNS) represents a transformative approach for managing a broad spectrum of inflammatory and autoimmune conditions, including rheumatoid arthritis and inflammatory bowel disease. This comprehensive review delineates the mechanisms underlying VNS, emphasizing the cholinergic anti-inflammatory pathway, and explores interactions within the neuro-immune and vagus-gut axes based on both clinical outcomes and pre-clinical models. Clinical applications have confirmed the efficacy of VNS in managing specific autoimmune diseases, such as rheumatoid arthritis, and chronic inflammatory conditions like inflammatory bowel disease, showcasing the variability in stimulation parameters and patient responses. Concurrently, pre-clinical studies have provided insights into the potential of VNS in modulating cardiovascular and broader inflammatory responses, paving the way for its translational application in clinical settings. Innovations in non-invasive VNS technology and precision neuromodulation are enhancing its therapeutic potential, making it a viable option for patients who are unresponsive to conventional treatments. Nonetheless, the widespread adoption of this promising therapy is impeded by regulatory challenges, patient compliance issues, and the need for extensive studies on long-term efficacy and safety. Future research directions will focus on refining VNS technology, optimizing treatment parameters, and exploring synergistic effects with other therapeutic modalities, which could revolutionize the management of chronic inflammatory and autoimmune disorders.

Targeting TNF/TNFR superfamilies in immune-mediated inflammatory diseases

Dysregulated signaling from TNF and TNFR proteins is implicated in several immune-mediated inflammatory diseases (IMIDs). This review centers around seven IMIDs (rheumatoid arthritis, systemic lupus erythematosus, Crohn's disease, ulcerative colitis, psoriasis, atopic dermatitis, and asthma) with substantial unmet medical needs and sheds light on the signaling mechanisms, disease relevance, and evolving drug development activities for five TNF/TNFR signaling axes that garner substantial drug development interest in these focus conditions. The review also explores the current landscape of therapeutics, emphasizing the limitations of the approved biologics, and the opportunities presented by small-molecule inhibitors and combination antagonists of TNF/TNFR signaling.

Vagus nerve stimulation with a small total charge transfer improves motor behavior and reduces neuroinflammation in a mouse model of Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative disease characterized by the loss of dopaminergic (DA) neurons in the substantia nigra (SN). Conventional treatments are ineffective in reversing disease progression. Recently, the therapeutic and rehabilitation potential of vagus nerve stimulation (VNS) in PD has been explored. However, the underlying mechanisms remain largely unknown. In this study, we investigated the neuroprotective effects of VNS in a lateral lesioned mice model of PD. Excluding controls, experimental mice received cuff electrode implantation on the left vagus nerve and 6-hydroxydopamine administration into the bilateral striatum. After ten days, electrical stimulation was delivered for 11 consecutive days onto PD animals. Behavioral tests were performed after stimulation. The expression of TH, Iba-1, GFAP, adrenergic receptors and cytokines in the SN and striatum was detected by immunofluorescence or western blotting. The activity of noradrenergic neurons in the locus coeruleus (LC) was also measured. Our results suggest that VNS improved behavioral performance in rod rotation, open field tests and pole-climbing tests in PD mice, accompanied by a decrease in the loss of dopaminergic neurons in the SN and increased TH expression in the striatum. Neuroinflammation-related factors, such as GFAP, Iba-1, TNF-α and IL-1β were also suppressed in PD mice after VNS compared to those without treatment. Furthermore, the proportion of c-Fos-positive noradrenergic neurons in the LC increased when animals received VNS. Additionally, the expression of the adrenergic receptor of α1BR was also upregulated after VNS compared to PD mice. In conclusion, VNS has potential as a novel PD therapy for neuroprotective effects, and indicate that activation of norepinephric neurons in LC may plays an important role in VNS treatment for PD.

Physiopathological Roles of White Adiposity and Gut Functions in Neuroinflammation

White adipose tissue (WAT) and the gut are involved in the development of neuroinflammation when an organism detects any kind of injury, thereby triggering metainflammation. In fact, the autonomous nervous system innervates both tissues, although the complex role played by the integrated sympathetic, parasympathetic, and enteric nervous system functions have not been fully elucidated. Our aims were to investigate the participation of inflamed WAT and the gut in neuroinflammation. Firstly, we conducted an analysis into how inflamed peripheral WAT plays a key role in the triggering of metainflammation. Indeed, this included the impact of the development of local insulin resistance and its metabolic consequences, a serious hypothalamic dysfunction that promotes neurodegeneration. Then, we analyzed the gut-brain axis dysfunction involved in neuroinflammation by examining cell interactions, soluble factors, the sensing of microbes, and the role of dysbiosis-related mechanisms (intestinal microbiota and mucosal barriers) affecting brain functions. Finally, we targeted the physiological crosstalk between cells of the brain-WAT-gut axis that restores normal tissue homeostasis after injury. We concluded the following: because any injury can result not only in overall insulin resistance and dysbiosis, which in turn can impact upon the brain, but that a high-risk of the development of neuroinflammation-induced neurodegenerative disorder can also be triggered. Thus, it is imperative to avoid early metainflammation by applying appropriate preventive (e.g., lifestyle and diet) or pharmacological treatments to cope with allostasis and thus promote health homeostasis.