Vagus nerve stimulation attenuates the systemic inflammatory response to endotoxin

Autonomic modulation of the immune response and implications for CNS malignancies

While the central nervous system (CNS) has long been known to regulate global physiologic processes, its role in regulating immune responses has only relatively recently been appreciated. Specifically, CNS input via the autonomic nervous system (ANS) is increasingly emerging as a crucial modulator of immune responses in numerous pathologies, though understanding of the role of these pathways in malignancy is limited. Herein, we provide an overview of CNS-immune signaling pathways, outline the evidence of ANS inputs to immune organs, provide a detailed description of the impact of ANS signaling on immune cell functions, and consider the implications of ANS-immune regulation for the antitumor immune response and CNS inflammation, with a specific focus on how these factors coalesce to impact the antitumor immune response in intracranial malignancies. This review concludes by highlighting the need to better understand cancer neuro-immunology, the tripartite interactions of malignancy and immune cells within the unique niche of the nervous system.

Decoding the neuroimmune axis in colorectal cancer: From neural circuitry to therapeutic innovation

The nervous and immune systems are two major components that maintain body homeostasis, with their functional roles often overlapping significantly. Both systems are capable of identifying, integrating, and organizing responsive reactions to various external stimuli. The gut, referred to as the "second brain" and the largest immune organ in the body, serves as the most frequent focal site for neuroimmune interactions. Colorectal cancer (CRC), as the predominant solid tumor arising in this neuroimmune-rich microenvironment, remains understudied through the lens of neuroimmune regulatory mechanisms. This review systematically synthesizes current evidence to elucidate the neuroimmune axis in CRC pathogenesis, with particular emphasis on neuroimmune crosstalk-mediated remodeling of tumor immunity. We comprehensively catalog the immunomodulatory effects exerted by principal neuroregulatory mediators, categorized as: (1) neurotransmitters (glutamate, glutamine, γ-aminobutyric acid, epinephrine, norepinephrine, dopamine, serotonin, acetylcholine, and gaseous signaling molecules); (2) neuropeptides (substance P, calcitonin gene-related peptide, vasoactive intestinal peptide); and (3) neurotrophic factors. Furthermore, we critically evaluate the translational prospects and therapeutic challenges of targeting neuroimmune pathways and propose strategic priorities and research focuses for advancing the development of neuroimmune interaction-related therapeutic approaches in CRC.

Spontaneous and pharmacologically induced hypothermia protect mice against endotoxic shock

BACKGROUND AND PURPOSE

Despite the well-known occurrence of hypothermia during sepsis, its underlying biological nature and adaptive value remain debated.

EXPERIMENTAL APPROACH

Using indirect calorimetry, telemetry, thermal gradient studies and pharmacological studies, we examined the thermal and metabolic responses of mice treated with a shock-inducing lethal dose of lipopolysaccharide (LPS).

KEY RESULTS

We report that LPS-treated mice undergo spontaneous hypothermia, driven by hypometabolism and cold-seeking behaviours, even when animals approach the end of life. Conversely, rewarming LPS-treated mice at 30°C delayed hypothermia but worsened mortality, thus highlighting the adaptive importance of hypothermia. Additionally, we show that LPS-induced hypothermia was partly mediated by peripheral neurotensin expressed in response to vascular toll-like receptor 4 (TLR4) signalling. The administration of a neurotensin analogue (JMV449) induced pharmacological hypothermia and significantly ameliorated the clinical presentation and lethality rates in LPS-treated mice. Moreover, the therapeutic benefits of pharmacological hypothermia were prevented when LPS-treated mice were switched to 30°C. Lastly, these beneficial outcomes were attributed to a reduction in oxygen consumption, metabolic stress and cytopathic hypoxia, rather than the modulation of the cytokine storm.

CONCLUSION AND IMPLICATIONS

Collectively, our findings indicate that spontaneous and pharmacologically-induced hypothermia protect against endotoxic shock.

Enhancing seizure control in ultra-refractory postencephalitic epilepsies using multinodal network neuromodulation

This case series reports the formidable challenge posed by postencephalitic epilepsies, characterized by frequent drug-resistant seizures and neuropsychiatric and cognitive comorbidities. Polypharmacy is frequently required, and surgical resection may not be feasible due to multifocality. Neuromodulation therapies, including Deep Brain Stimulation (DBS) and Responsive Neurostimulation (RNS), offer a potential lifeline. In this case series, we shed light on the intricate landscape of seizure management and neuropsychiatric comorbidities in five individuals with frequent seizures (often weekly) and ultra-refractory epilepsy (defined as resistance to more than six different antiseizure medications, including failed epilepsy surgery) following catastrophic encephalitis. Four out of five patients achieved at least 50% reduction in seizure frequency following multimodal neuromodulation interventions. Moreover, we underscore the pivotal role of RNS electrocorticography (ECoG) in monitoring the epileptiform burden to guide therapy. Postencephalitic patients often present with a complex interplay of epileptic and nonepileptic (including neuropsychiatric) events, necessitating distinct therapeutic approaches. RNS ECoG emerges as a critical tool for differentiation and tailored therapy. While our findings highlight the potential effectiveness of neuromodulation in managing postencephalitic epilepsy, further research is needed to identify predictors of treatment response and explore the application of these therapies in chronic epilepsy caused by encephalitis. Overall, neuromodulation offers hope for improving these patients' quality of life.

Contributions of Noncardiac Organ-Heart Immune Crosstalk and Somatic Mosaicism to Heart Failure: Current Knowledge and Perspectives

Heart failure is the final outcome of most cardiovascular diseases and shares risk factors with other cardiovascular pathologies. Among these, inflammation plays a central role in disease progression and myocardial remodeling. Over the past 2 decades, numerous studies have explored immune-related mechanisms in cardiovascular disease, highlighting the importance of immune cross-talk between the heart and extra-cardiac organs, including bone marrow, spleen, liver, gut, and adipose tissue. This review examines how immune interactions among these organs contribute to heart failure pathogenesis, with a focus on clonal hematopoiesis, an age-related alteration of hematopoietic stem cells that fosters pathological bone marrow-heart communication. Additionally, we explore recent advances in the understanding of clonal hematopoiesis and its role in heart failure, emphasizing its implications for prognosis and potential therapeutic interventions. By integrating insights from immunology, metabolism, and aging, we provide a comprehensive perspective on the immunologic determinants of heart failure, paving the way for precision medicine approaches aimed at mitigating cardiovascular risk.

Neural Mechanisms in Cardiovascular Health and Disease

Although the neurocardiac axis is central to cardiovascular homeostasis, its dysregulation drives heart failure and cardiometabolic diseases. This review examines the bidirectional interplay between the autonomic nervous system and the heart, highlighting the role of this interplay in disease progression and its therapeutic potential. The autonomic nervous system modulates cardiac function and vascular tone through its sympathetic and parasympathetic branches. However, in heart failure, chronic sympathetic overdrive and parasympathetic withdrawal exacerbate myocardial remodeling and metabolic dysfunction, both of which are exacerbated by cardiometabolic conditions such as obesity and diabetes. These conditions are increasingly recognized to impair neurocardiac regulation, thereby promoting inflammation and adverse outcomes. An important emerging area concerns neuroimmune control, in which the brain orchestrates systemic inflammation through circuits involving the bone marrow, spleen, and other organs, thereby amplifying cardiovascular damage. This neuroimmune axis integrates peripheral signals to influence immune responses that contribute to disease progression. Lifestyle factors, such as stress, sleep, exercise, and diet, affect autonomic and immune balance and, thus, cardiovascular disease. Therapeutically, targeting neurocardiac and neuroimmune pathways pharmacologically or via neuromodulation (eg, vagal or splenic nerve stimulation) offers promise although the clinical translation of the latter remains challenging. In this review, we synthesize preclinical and clinical data to highlight the neurocardiac axis as a critical nexus in heart failure and cardiometabolic disease. Harnessing neuroimmune and neurocardiac interactions may inform precision approaches to reduce the burden of these conditions.

The sensory neuroimmune frontier

Sensing and recognition are key properties of both the immune and nervous systems. In the immune system, pattern recognition or antigen-specific receptors represent classic motifs in innate and adaptive immunity, respectively. In the nervous system, there is a major anatomic division between how we sense stimuli from within the body (vagal sensory nervous system) and the outside world (somatosensory nervous system). However, in the last 5 years, there has been an explosion of discoveries revealing interactions between the immune and the sensory nervous systems that govern an array of physiologic and pathologic processes including allergy, infection, autoimmunity, regeneration, cancer, and beyond. Herein, we highlight recent advances that demonstrate how peripheral sensory neuroimmunology has emerged as a powerful field that provides new insights into classic immunologic processes including immune hypersensitivity, inflammation, and tissue homeostasis.

Dysfunction of cholinergic neuron in nucleus ambiguous aggravates sepsis-induced lung injury via a GluA1-dependment mechanism

Clinical and neuropathological observations suggest that patients with sepsis may have brainstem autonomic dysfunction. However, the influence of peripheral inflammation on vagal preganglionic neurons is poorly understood. Our hypothesis is that sepsis-induced central vagus dysfunction affects the cholinergic anti-inflammatory pathway and consequently contributes to respiratory failure. Here, we identified neuron apoptosis in the nucleus ambiguus (NA) after sepsis; NA is not only a component of the efferent arm of the inflammatory reflex but also plays an important role in respiratory regulation. Conditional ablation of cholinergic neurons in the NA leads to a decrease in vagus nerve firing, significant impairment of respiratory function, and inflammatory changes in lung tissues. The accumulation of glutamate and increased expression of Ca2+-permeable (CP)-AMPA receptors (AMPARs) mediated the excitotoxicity of NA neurons. Microinjection of IEM1460 (a selective blocker of GluA2- lacking AMPARs) partly rescued vagus firing and respiratory function in mice with sepsis. We showed that peripheral sepsis caused brainstem inflammation and impaired the cholinergic anti-inflammatory pathway after infection. We conclude that central efferent vagus dysfunction may impact vital organ systems in sepsis.

Investigating the effect of neuro-immune communication on immune responses in health and disease: Exploring immunological disorders

Recent recognition of the intricate nervous-immune system interplay has prompted research into the specific cellular components involved in these interactions. Emerging evidence suggests that immune and neural cells collaborate within distinct units and act in concert to regulate tissue function and provide protection. These specialized neuro-immune cell units have been identified in diverse body tissues, ranging from lymphoid organs to the bone marrow and mucosal barriers. Their significance has become increasingly apparent as they are recognized as pivotal regulators influencing a broad spectrum of physiological and pathological processes. This recognition extends to critical roles in hematopoiesis, organ function, inflammatory responses, and intricate tissue repair processes. This review explores the bidirectional communication between the nervous and immune systems. The focus is on understanding the profound impact of this communication on immune cells within key anatomical sites, such as the bone marrow, gastrointestinal tract, and lymphoid organs. By examining these interactions, this review aims to shed light on how this intricate network operates under normal and pathological conditions, offering insights into the mechanisms underlying health and disease.

A transcriptional atlas of gut-innervating neurons reveals activation of interferon signaling and ferroptosis during intestinal inflammation

Enteric infections often cause long-term sequelae, including persistent gastrointestinal symptoms, such as pain, discomfort, or irritable bowel syndrome. The plethora of sensory symptoms indicates that gut-innervating neurons might be directly affected by inflammation. However, sequencing studies of neurons in the gastrointestinal tract are hampered by difficulties in purifying neurons, especially during inflammation. Activating a nuclear GFP tag selectively in neurons enabled sort purification of intrinsic and extrinsic neurons of the gastrointestinal tract in models of intestinal inflammation. Using bulk and single-nucleus RNA sequencing, we mapped the whole transcriptomic landscape and identified a conserved neuronal response to inflammation, which included the interferon signaling and ferroptosis pathway. Deletion of the interferon receptor 1 in neurons regulated ferroptosis, neuronal loss, and consequently gut-transit time. Collectively, this study offers a resource documenting neuronal adaptation to inflammatory conditions and exposes the interferon and ferroptosis pathways as signaling cascades activated in neurons during inflammation.

A Randomized Controlled Trial of Sugammadex versus Neostigmine for Reversal of Rocuronium on Gastric Emptying in Adults Undergoing Elective Colorectal Surgery

BACKGROUND

Gastrointestinal function is mediated by the cholinergic pathway, which is impacted by neostigmine and glycopyrrolate, but not sugammadex. We hypothesized that sugammadex is associated with earlier gastric emptying in adults undergoing colorectal surgery, compared to neostigmine-glycopyrrolate.

METHODS

Patients were enrolled in a pragmatic, single-center, patient and assessor-blinded, randomized, controlled trial. At skin closure, subjects were randomized to sugammadex 2 mg/kg or neostigmine 0.07 mg/kg and glycopyrrolate (0.2 mg per 1 mg of neostigmine). The primary end point, gastric emptying, was assessed with the paracetamol absorption test, with greater area under the curve representing faster gastric emptying. Secondary end points included time to first bowel movement, time to achieve adequate reversal (train-of-four ratio ≥0.9), gastrointestinal complications, hospital length of stay, and postanesthesia care unit recovery time. The analysis was intention-to-treat.

RESULTS

All 60 patients randomized to sugammadex received the allocated intervention. Of 60 patients randomized to neostigmine-glycopyrrolate, 56 received neostigmine-glycopyrrolate, 2 received sugammadex, and 2 received both agents. Gastric emptying did not differ significantly between sugammadex (mean [standard deviation {SD}] area under the curve {AUC} 1118 [122]) and neostigmine (AUC 1130 [117], P = .58). Sugammadex treatment was associated with shorter time to first bowel movement (44.3 hours [33.8] vs 61.0 hours [43.0]; difference = 16.7 hours, 95% confidence interval {CI}, [2.3-31.1], P = .02) and time to adequate reversal (5.2 minutes [6.3] vs 17.5 minutes [10.1]; difference = 12.3 minutes, 95% CI, [9.2-15.4], P < .001). Neostigmine-glycopyrrolate treatment was not associated with a significant increase in gastrointestinal complications (32% vs 17%; OR = 2.3, 95% CI, [0.9-6.2], P = .09), a longer hospital length of stay (7.8 days [19.8] vs 4.8 days [4.9]; difference = 3 days, 95% CI, [-2.2 to 8.3], P = .27), or a difference in postanesthesia care unit recovery time (108 minutes [56.4] vs 115 minutes [50.3]; difference= -6.9 minutes, 95% CI, [-26.4 to 12.6], P = .48). Adverse events were similar between groups.

CONCLUSIONS

Sugammadex treatment was not associated with faster gastric emptying (primary end point). Regarding prespecified secondary end points, sugammadex treatment was associated with a 12.3-minute shorter time to adequate reversal in real-life practice conditions, but it did not benefit the proportion of subjects with a gastrointestinal complication, hospital length of stay, or postanesthesia care unit recovery time. Further studies are needed to confirm our finding that sugammadex is associated with a clinically significant 16.7-hour shorter time to first bowel movement, and to establish the role of sugammadex in colorectal surgery enhanced recovery protocols.

Neuroimmune cross-talk in heart failure

Heart failure (HF) is characterized by autonomic nervous system (ANS) imbalance and low-grade chronic inflammation. The bidirectional relationship between the ANS and immune system (IS) is named 'neuroimmune cross-talk' (NICT) and is based on common signaling molecules, receptors, and pathways. NICT may be altered in HF, and neuroinflammation seems to be a main driver of HF progression. In HF, heightened sympathetic nerve activity triggers inflammatory cascades that lead to cardiomyocyte death and myocardial interstitial fibrosis. Concurrently, parasympathetic withdrawal may impair the cholinergic anti-inflammatory pathway, with a less effective immune response to infections or inflammatory events. Additionally, microglial activation and inflammatory molecules contribute to autonomic imbalance by acting on central nuclei and peripheral visceral feedbacks, which in turn promote adverse cardiac remodeling, HF decompensation, and potentially life-threatening arrhythmias. Therefore, neuroinflammation has been identified as a potential target for treatment. Pharmacological antagonism of the neurohormonal system remains the cornerstone of chronic HF therapy. While some drugs used in HF management may have additional benefits due to their anti-inflammatory properties, clinical trials targeting inflammation in patients with HF have so far produced inconclusive results. Nevertheless, considering the pathophysiological relevance of NICT, its modulation seems an appealing strategy to optimize HF management. Current research is therefore investigating novel pharmacological targets for anti-inflammatory drugs, and the immunomodulatory properties of denervation approaches and bioelectronic medicine devices targeting NICT and neuroinflammation in HF. A deeper understanding of the complex relationship between the ANS and IS, as outlined in this review, could therefore facilitate the design of future studies aimed at improving outcomes by targeting NICT in patients with HF.

Vagus nerve modulates acute-on-chronic liver failure progression via CXCL9

BACKGROUND

Hepatic inflammatory cell accumulation and the subsequent systematic inflammation drive acute-on-chronic liver failure (ACLF) development. Previous studies showed that the vagus nerve exerts anti-inflammatory activity in many inflammatory diseases. Here, we aimed to identify the key molecule mediating the inflammatory process in ACLF and reveal the neuroimmune communication arising from the vagus nerve and immunological disorders of ACLF.

METHODS

Proteomic analysis was performed and validated in ACLF model mice or patients, and intervention animal experiments were conducted using neutralizing antibodies. PNU-282987 (acetylcholine receptor agonist) and vagotomy were applied for perturbing vagus nerve activity. Single-cell RNA sequencing (scRNA-seq), flow cytometry, immunohistochemical and immunofluorescence staining, and clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) technology were used for in vivo or in vitro mechanistic studies.

RESULTS

The unbiased proteomics identified C-X-C motif chemokine ligand 9 (CXCL9) as the greatest differential protein in the livers of mice with ACLF and its relation to the systematic inflammation and mortality were confirmed in patients with ACLF. Interventions on CXCL9 and its receptor C-X-C chemokine receptor 3 (CXCR3) improved liver injury and decreased mortality of ACLF mice, which were related to the suppressing of hepatic immune cells' accumulation and activation. Vagus nerve stimulation attenuated while vagotomy aggravated the expression of CXCL9 and the severity of ACLF. Blocking CXCL9 and CXCR3 ameliorated liver inflammation and increased ACLF-associated mortality in ACLF mice with vagotomy. scRNA-seq revealed that hepatic macrophages served as the major source of CXCL9 in ACLF and were validated by immunofluorescence staining and flow cytometry analysis. Notably, the expression of CXCL9 in macrophages was modulated by vagus nerve-mediated cholinergic signaling.

CONCLUSIONS

Our novel findings highlighted that the neuroimmune communication of the vagus nerve-macrophage-CXCL9 axis contributed to ACLF development. These results provided evidence for neuromodulation as a promising approach for preventing and treating ACLF.

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.

Nervous system-gut microbiota-immune system axis: future directions for preventing tumor

Tumor is one of the leading causes of death worldwide. The occurrence and development of tumors are related to multiple systems and factors such as the immune system, gut microbiota, and nervous system. The immune system plays a critical role in tumor development. Studies have also found that the gut microbiota can directly or indirectly affect tumorigenesis and tumor development. With increasing attention on the tumor microenvironment in recent years, the nervous system has emerged as a novel regulator of tumor development. Some tumor therapies based on the nervous system have also been tested in clinical trials. However, the nervous system can not only directly interact with tumor cells but also indirectly affect tumor development through the gut microbiota. The nervous system-mediated gut microbiota can regulate tumorigenesis, growth, invasion, and metastasis through the immune system. Here, we mainly explore the potential effects of the nervous system-gut microbiota-immune system axis on tumorigenesis and tumor development. The effects of the nervous system-gut microbiota-immune system axis on tumors involve the nervous system regulating immune cells through the gut microbiota, which can prevent tumor development. Meanwhile, the direct effects of the gut microbiota on tumors and the regulation of the immune system by the nervous system, which can affect tumor development, are also reviewed.

Exploring the Potential Role of the Cholinergic Anti-Inflammatory Pathway from the Perspective of Sepsis Pathophysiology

Sepsis is one of the most prevalent conditions in critical care medicine and is characterized by a high incidence, mortality, and poor prognosis, with no specific treatment currently available. The pathogenesis of sepsis is complex with a dysregulated inflammatory response at its core. If the initial inflammatory response is not promptly controlled, patients often develop multiple organ dysfunction syndrome or die, whereas survivors may experience post-sepsis syndrome. Regulation by the central and autonomic nervous systems is essential for maintaining inflammatory homeostasis. Among these, the cholinergic anti-inflammatory pathway (CAP) has been extensively studied in sepsis owing to its significant role in modulating inflammatory responses. Recent advancements in CAP-related interventions include minimally invasive vagus nerve stimulation, novel α7nAchR-targeting drugs, serum choline acetyltransferase and cholinesterase, acupuncture, and focused ultrasound stimulation therapy. This review primarily discusses the advantages, limitations, and therapeutic prospects of these approaches. Additionally, heart rate variability, which reflects changes in autonomic nervous system function, can serve as an indicator for assessing the functional status of the vagus nerve. In summary, modulation of inflammatory responses through the vagus nerve-mediated CAP represents a potential strategy for achieving precision medicine for sepsis. Future research should focus on conducting high-quality clinical studies on CAP-based therapies in the context of sepsis-induced inflammatory dysregulation. Incorporating indicators to evaluate the autonomic nervous system function may further elucidate the impact of inflammatory dysregulation in the body.

The effect of corticotropin-release hormone on duodenal permeability and immune activation in healthy volunteers in a double-blind placebo-controlled study

In functional dyspepsia, increased gut permeability, low-grade inflammation, and altered sensorimotor function have been reported. Both stress and corticotropin-release hormone (CRH) have been shown to increase small bowel permeability in a mast-cell-dependent manner. Moreover, eosinophil-derived CRH has been implicated in mast cell activation. The aim of this study was to evaluate whether CRH administration alters duodenal permeability and immune activation in healthy volunteers (HVs). An intravenous bolus of 100-µg CRH or placebo was administered in HVs in a crossover, double-blind, randomized manner. Two hours later, a gastroscopy was performed to measure permeability in Ussing chambers and to count mast cells and eosinophils on duodenal biopsies. Supernatant was assessed for eosinophil-derived neurotoxin (EDN), tryptase, and chymase. In addition, CRH was administrated ex vivo to baseline biopsies pretreated with or without lodoxamide. Results are described as means ± SD. P values < 0.05 were considered significant. Twenty HVs completed the study. Mast cell or eosinophil counts were not significantly altered after CRH versus Placebo (respectively P = 0.31 and P = 0.069). Tryptase, but not chymase, significantly decreased after CRH (respectively P = 0.037 and P = 0.44) with a trend for a decrease in EDN (P = 0.053). Permeability was unaltered comparing both conditions. Ex vivo, transepithelial electrical resistance significantly decreased after CRH exposure compared with baseline (P = 0.010), which was not prevented by pretreatment with lodoxamide. In vivo CRH administration reduced tryptase levels in the supernatant of duodenal biopsies without affecting permeability, whereas ex vivo duodenal permeability increased regardless of mast cell stabilization. These results suggest the involvement of mast cells in regulating gut permeability in HVs in response to CRH, possibly influenced by in vivo compensatory mechanisms.NEW & NOTEWORTHY Our investigation breaks new ground by directly examining the effects of corticotropin-release hormone (CRH) on duodenal alterations, including permeability and immune activation, in healthy subjects. Intriguingly, our findings highlight disparities between ex vivo and in vivo pathways affecting duodenal permeability, offering novel insights into the potential pathophysiology of CRH on the duodenum.

Immunomodulatory effects of calorie restriction and its mimetics: A new potential therapeutic approach for autoimmune diseases

Calorie restriction (CR) is a well known intervention associated with multifaceted anti-aging and pro-longevity health benefits. It induces complex physiological cellular and molecular adaptations, resulting in the fine-tuning of metabolic and immune responses in both homeostatic and diseased states. It has thus been extensively studied both preclinically and clinically, uncovering its therapeutic potential against inflammatory conditions, particularly autoimmune diseases. CR mimetics (CRMs), that is, molecules that mimic CR's effects, have also been widely investigated to counteract inflammatory states associated with numerous diseases, including autoimmunity. However, a comprehensive overview of how CR and CRMs modulate different aspects of immune responses, thereby potentially modifying autoimmunity, is still lacking. Here, we reviewed the latest progress on the impacts of CR and CRMs on the immune system and the current evidence on their potential translation in the clinical management of people with autoimmune diseases. First, we summarized different types of CR and CRMs and their main mechanisms of action. We next reviewed comprehensively how CR and CRMs modulate immune cells and discussed up-to-date preclinical and clinical advances in using CR and CRMs in the context of some of the most common autoimmune diseases. Finally, challenges faced in CR-related research and its translation into the clinic are discussed. SIGNIFICANCE STATEMENT: Calorie restriction (CR) encompasses various approaches for daily or intermittent reduction in calorie intake while maintaining adequate nutrient intake. It acts through cell-intrinsic and -extrinsic pathways to modulate immune cell functions. CR is emerging as a strategy for autoimmune disease management. CR's effects could be partially mimicked by molecules called CR mimetics, which are proposed to achieve CR's effects without reducing food intake. CR and CR mimetics have been tested as promising potential therapeutics in preclinical and clinical autoimmune disease studies.

Neural representation of cytokines by vagal sensory neurons

The nervous system coordinates with the immune system to detect and respond to harmful stimuli. Inflammation is a universal response to injury and infection that involves the release of cytokines. While it is known that information about cytokines is transmitted from the body to the brain, how the nervous system encodes specific cytokines in the form of neural activity is not well understood. Using in vivo calcium imaging, we show that vagal sensory neurons within the nodose ganglia exhibit distinct real-time neuronal responses to inflammatory cytokines. Some neurons respond selectively to individual cytokines, while others encode multiple cytokines with distinct activity patterns. In male mice with induced colitis, inflammation increased the baseline activity of these neurons but decreased responsiveness to specific cytokines, reflecting altered neural excitability. Transcriptomic analysis of vagal ganglia from colitis mice revealed downregulation of cytokine signaling pathways, while neuronal activity pathways were upregulated. Thus, nodose ganglia neurons perform real-time encoding of cytokines at the first neural station in a body-brain axis, providing a new framework for studying the dynamic nature of neuroimmune communication.

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.

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.

Hydrotherapy and acupressure in restless legs syndrome: results of a randomized, controlled, three-armed, pilot study (HYDRAC-study)

Study objectives

Non-pharmacological interventions for restless legs syndrome (RLS) are frequently used, although scientific evidence remains limited. The study aimed to investigate the feasibility and effects of self-applied hydrotherapy and self-applied acupressure in patients with RLS.

Methods

In a three-armed randomized single-center open exploratory pilot study, adults with moderate to severe RLS were randomly allocated to 6 weeks of daily hydrotherapy plus routine care (HT group), acupressure plus routine care (AP group), or routine care alone (RC group). Outcome measures included RLS symptom severity (IRLS), disease-specific quality of life (RLSQoL), the impression of change (PGI-C), health-related quality of life (SF-12), psychological outcomes (SGW-B, HADS, and GSE), and adherence and adverse events (AEs) after 6 and 12 weeks.

Results

Fifty-four adults (mean age 57.5 ± 11.4 years, 63% women) were included. The study showed good feasibility with an 83% retention rate. After 6 weeks, baseline-adjusted mean IRLS scores were 19.8 (95% [16.4, 23.2]) for HT, 22.9 (19.2, 26.6) for AP, and 24.0 (20.8, 27.2) for RC. RLSQoL adjusted means were 65.3 (59.7, 70.9) for HT, 68.3 (62.3, 74.3) for AP, and 56.2 (50.9, 61.5) for RC, after 6 weeks. Both interventions were safe, with high adherence rates.

Conclusion

Self-applied hydrotherapy and acupressure appear to be feasible and safe interventions for patients with RLS. This exploratory pilot study suggests potential benefits, though larger, well-designed confirmatory studies are needed to validate these findings.

Clinical trial registration

This study was registered in the German Clinical Trials Register (number DRKS00029960) on August 09, 2022. https://drks.de/search/de/trial/DRKS00029960.

Beta Adrenergic Signaling as a Therapeutic Target for Autoimmunity

Background

We recently identified a molecular mechanism involving beta-adrenergic 1 and 2 receptors (β1/2) in the development of T H 17 lymphocytes. Pharmacological and genetic inhibition of these receptors in combination, but not separately, impaired the ability of T-lymphocytes to produce proinflammatory interleukin 17A (IL-17A) and instead promoted the production of protective T reg cells that secrete anti-inflammatory interleukin-10 (IL-10). However, it remained unclear whether this regulatory mechanism could serve as a novel therapeutic approach for autoimmune disorders mediated by IL-17A-producing T-lymphocytes.

Methods

Multiple sclerosis (MS) is an inflammatory demyelinating disorder of the central nervous system (CNS) characterized by an autoimmune response where both T-lymphocytes and IL-17A are implicated in the pathogenesis of the disease. Using an animal model of MS, termed experimental autoimmune encephalomyelitis (EAE), we addressed the impact of beta adrenergic receptor blockade (genetically and pharmacologically) on EAE disease progression, severity, and T H 17/T reg balance.

Results

The genetic deletion β1/2 receptors, either systemically or specifically in T-lymphocytes, significantly attenuated EAE disease severity and animal weight loss. Pharmacological blockade of β1/2 receptors with either propranolol (lipophilic) or nadolol (aqueous) limited disease severity and weight loss similar to the genetic models. All models showed degrees of shifted T H 17/T reg balance (suppressing T H 17 and promoting T reg ) and decreased T-lymphocyte IL-17A production. Importantly, pharmacological blockade was initiated at the time of symptom development, which mimics the typical time where diagnosis of disease would occur.

Conclusions

Our data depict a novel role for β1/2 adrenergic signaling in the control of T H 17/T reg cells in EAE. These findings provide new insight into the disease progression as well as provide a potential new pharmacological therapy for IL-17A-related autoimmune diseases.

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.

Role of Microencapsulated Essential Oil and Pepper Resin in the Diet of Cows in the Third Lactation Phase on Immunological Pathways

The objective was to determine whether dairy cows may activate traditional and alternative inflammatory pathways by consuming a combination of a phytogenic diet (essential oil and pepper resin). Twenty pregnant Jersey cows in the final (third) lactation phase (260 days in milk) were divided into two groups: control, with no additive consumption, and test, with the addition of the phytogenic to the concentrate portion of the diet (150 mg/day/kg dry matter). Blood samples were collected on experimental days 1, 7, 14, 21, 28, 35, and 42 by coccygeal vein puncture to assess the complete blood count, serum biochemistry of levels of total protein, albumin, and globulin, as well as carbohydrate metabolism (glucose), lipid metabolism (cholesterol and triglycerides), protein metabolism (urea), activities of hepatic enzymes (gamma-glutamyl transferase (GGT) and aspartate aminotransferase (AST)), cytokine levels (interleukins IL-1β, IL-6, and IL-10), antioxidant response [thiobarbituric acid reactive substances (TBARS), reactive oxygen species (ROS), total thiol (PSH), and non-protein thiol (NPSH), and glutathione S(GST)], cholinergic system [total cholinesterase (ChE) and acetylcholinesterase (AChE)], purinergic signaling [NTPDase, 5'ectonucleotidase and adenosine deaminase (ADA)], and energetic metabolism enzymes [creatine kinase (CK), pyruvate kinase (PK), and adenylate kinase (AK)]. Productive performance was assessed through feed intake and milk production. The results revealed that the use of phytogenic compounds significantly influenced the cholinergic system and purinergic signaling associated with immunology. The reduction in cholinesterase (ChE) activity and the increase in acetylcholinesterase (AChE) activity in lymphocytes suggest the modulation of the cholinergic system, enhancing the immune response. Furthermore, the elevated activity of adenosine deaminase (ADA) in lymphocytes and platelets, together with increased ATP and ADP hydrolysis in platelets, indicates the beneficial regulation of purinergic signaling, potentially contributing to inflammatory modulation. These effects were accompanied by a lower production of pro-inflammatory cytokines (IL-1β and IL-6) and a higher production of IL-10, reinforcing an anti-inflammatory profile. The reduced leukocyte and lymphocyte counts may reflect a lower inflammatory demand, while the increased levels of NPSH and GST antioxidants suggest cellular protection. Despite these physiological changes, productive performance and milk quality remained unaffected. In summary and practical terms, including this additive in the cows' diet benefits the cow's health in the final third of gestation when the animal already has a reduced immune response due to advanced gestation.

Structural basis for allosteric agonism of human α7 nicotinic acetylcholine receptors

The α7 nicotinic acetylcholine receptor (nAChR), a pentameric ligand-gated ion channel, plays important roles in cognition, neuroprotection, and anti-inflammation. As a potential drug target, α7 nAChR has different binding sites for different ligands, particularly agonists and positive allosteric modulators (PAMs). Ago-PAMs can both directly activate and allosterically modulate α7 nAChR. However, the mechanism underlying α7 nAChR modulation by ago-PAM has yet to be fully elucidated. Here, we present cryo-EM structures of α7 nAChR in complex with the ago-PAM GAT107 and Ca2+ in the open and desensitized states, respectively. Our results from both structural comparisons and functional assays suggest an allosteric mechanism underlying GAT107 modulation and calcium potentiation of α7 nAChR, involving local conformational changes in the ECD-TMD coupling region and a global structural rearrangement in the transmembrane domain. This work provides a new mechanism of α7 nAChR gating distinct from that of conventional agonist binding. These findings would aid in drug design and enrich our biophysical understanding of pentameric ligand-gated ion channels.

Emerging Technologies in Inflammatory Bowel Disease: A Minireview on Future Treatment Modalities

Inflammatory bowel disease (IBD) can present as either Crohn's disease or ulcerative colitis. Both phenotypes are inflammatory conditions of the gastrointestinal tract. Despite scientific advances, the overall incidence and morbidity of IBD continues to increase worldwide. Fortunately, we continue to develop novel therapies, in hopes of providing safer, more effective treatment options. Such therapies include cell therapy, exosome therapy, hyperbaric oxygen therapy, and central nerve stimulation. The aim of this review is to briefly highlight each of these novel therapeutic interventions as they relate to the treatment of IBD.

Microglial activation and neuroinflammation in acute and chronic cognitive deficits in sepsis

Sepsis is characterised by dysregulated immune responses to infection, leading to multi-organ dysfunction and high rates of mortality. With increasing survival rates in recent years long-term neurological and psychiatric consequences have become more apparent in survivors. Many patients develop sepsis associated encephalopathy (SAE) which encompasses the profound but usually transient neuropsychiatric syndrome delirium but also new brain injury that emerges in the months and years post-sepsis. It is now clear that systemic inflammatory signals reach the brain during sepsis and that very significant neuroinflammation ensues. The major brain resident immune cell population, the microglia, has been implicated in acute and chronic cognitive dysfunction in animal models of sepsis based on a growing number of studies using bacterial endotoxin and in polymicrobial sepsis models such as cecal ligation and puncture. The current review explores the effects of sepsis on the brain, focussing on how systemic insults translate to microglial activation and neuroinflammation and how this disrupts neuronal function and integrity. We examine what has been demonstrated specifically with respect to microglial activation, revealing robust evidence for a role for neuroinflammation in sepsis-induced brain sequelae but less clear information on the extent of the specific microglial contribution to this, arising from findings using global knockout mice, non-selective drugs and treatments that equally target peripheral and central compartments. There is, nonetheless, clear evidence that microglia do become activated and do contribute to brain consequences of sepsis thus arguing for improved understanding of these neuroinflammatory processes toward the prevention and treatment of sepsis-induced brain dysfunction.

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.

Heart Rate Variability and Cytokines are Involved in Anxiety in Breast Cancer Patients: A Cross-Sectional Study

OBJECTIVE

To explore the correlation between heart rate variability (HRV), peripheral cytokines, anxiety and pain scores in patients with breast cancer (BC).

METHODS

We collected blood samples from 100 BC patients and measured the concentrations of Interleukin 6 (IL-6), Interleukin 4 (IL-4) and Interferon gamma (IFN-γ). We collected the patients' 5-minute dynamic electrocardiograms and evaluated their anxiety and pain levels through the Anxiety Self-Rating Scale and the Short-Form McGill Pain Questionnaire (SF-MPQ) Scale.

RESULTS

Compared with patients in the high HRV group, the low HRV group had lower IL-4 levels and higher IFN-γ/IL-4 concentrations. At the same time, the level of anxiety was also higher, but there was no significant difference in pain. Spearman correlation analysis showed that the normal-to-normal cardiac intervals (SDNN), the square root of the mean of the sum of the squares of differences between adjacent normal-to-normal cardiac intervals (RMSSD), high frequency -HRV (HF-HRV) and IL-4 were positively correlated, SDNN and RMSSD were negatively correlated with IFN-γ/IL-4. HRV is negatively correlated with anxiety. Higher SDNN predicts higher IL-4 levels.

CONCLUSION

Our results indicate that BC patients with low HRV are associated with higher levels of inflammation and anxiety. Therefore, the measurement of HRV may serve as an objective and non-invasive measurement method for monitoring the immune system and anxiety problems of BC patients.

The innervated gut and critical illness

PURPOSE OF REVIEW

This review highlights brain-gut neuroimmune interactions in the context of critical illness. Neural regulation of inflammation, gut innervation, and the brain-gut axis in critical illness are discussed.

RECENT FINDINGS

Recent studies indicate that the brain-gut axis and the enteric nervous system are integral to the regulation of local and systemic inflammation. Experimental evidence suggests that neural reflexes control immune responses, and specific neural signals promote gastrointestinal homeostasis. The understanding of these interactions in the clinical context remains limited, necessitating further investigation. Notably, therapeutic interventions targeting neuro-immune pathways have shown promise in preclinical models, suggesting that a better understanding of the neuro-immune crosstalk in the critically ill may potentially identify novel therapeutic targets.

SUMMARY

Critical illness involves complex organ dysfunction, not least in the gastrointestinal system. A multitude of neuroimmune interactions between the intestinal wall, immune cells, peripheral nerves and the central nervous system regulate inflammation. While experimental evidence supports the role of neural reflexes in controlling immune responses, clinical validation is lacking in the context of critical care. Future research needs to explore whether specific neural signals or mechanisms of neuro-immune crosstalk can be harnessed to restore and support gastrointestinal homeostasis in the critically ill.

Cholinesterase and Inflammation: Exploring Its Role and Associations with Inflammatory Markers in Patients with Lower Extremity Artery Disease

Background: Inflammation is a major driver of atherosclerotic diseases including lower extremity artery disease (LEAD). Serum cholinesterase (ChE) has been shown to impact cardiovascular health and regulate inflammatory processes. Objectives: The aim of this study was to investigate the relationship between serum ChE levels and inflammatory markers in patients with hemodynamically relevant iliac artery stenosis, assessing its potential role in the inflammatory processes of lower extremity artery disease (LEAD). Methods: In the following retrospective data analysis, we investigated 150 patients with hemodynamically relevant iliac artery stenosis as documented by a delta peak systolic velocity (δPSV) ≥ 1.4 m/s and investigated the possible influence of ChE on established inflammatory markers, such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and hemoglobin-to-platelet ratio (HPR), along with other routine laboratory or vascular parameters. Results: ChE levels differed significantly between patients with stable claudication (Fontaine stage II) and critical ischemia (Fontaine stages III and IV): 7.76 mg/dL (6.55-8.7 mg/dL) vs. 6.77 mg/dL (5.85-7.48 mg/dL), p = 0.004. Using the spearman correlation coefficient, testing of NLR and ChE revealed a highly significant inverse correlation, with a coefficient of -0.303 (p < 0.001). Additionally, a weak inverse correlation was observed between PLR and ChE, with a coefficient of -0.162 (p = 0.049). Patients with an elevated body mass index (BMI) showed increased levels of serum ChE, with a spearman correlation coefficient of 0.298 (p < 0.001). Conclusions: The observed correlations in this study depict active inflammation in LEAD with an emphasis on patients with critical ischemia. Serum ChE could serve as a potential biomarker for inflammation in patients with LEAD, particularly in distinguishing between stable claudication and critical ischemia. Future research is needed to explore the role of ChE as a complementary biomarker, offering insights into the cholinergic regulation of inflammation in LEAD.

Differential senolytic inhibition of normal versus Aβ-associated cholinesterases: implications in aging and Alzheimer's disease

Cellular senescence is a hallmark of aging and the age-related condition, Alzheimer's disease (AD). How senescence contributes to cholinergic and neuropathologic changes in AD remains uncertain. Furthermore, little is known about the relationship between senescence and cholinesterases (ChEs). Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are important in neurotransmission, cell cycle regulation, and AD amyloid-β (Aβ) pathology. Senolytic agents have shown therapeutic promise in AD models. Therefore, we evaluated in vitro and in silico activity of senolytics, dasatinib (1), nintedanib (2), fisetin (3), quercetin (4), GW2580 (5), and nootropic, meclofenoxate hydrochloride (6), toward AChE and BChE. As ChEs associated with AD pathology have altered biochemical properties, we also evaluated agents 1-6 in AD brain tissues. Enzyme kinetics showed agents 1, 3, 4, and 6 inhibited both ChEs, while 2 and 5 inhibited only AChE. Histochemistry showed inhibition of Aβ plaque-associated ChEs (1 and 2: both ChEs; 5: BChE; 6: AChE), but not normal neural-associated ChEs. Modeling studies showed 1-6 interacted with the same five binding locations of both ChEs, some of which may be allosteric sites. These agents may exert their beneficial effects, in part, by inhibiting ChEs associated with AD pathology and provide new avenues for development of next-generation inhibitors targeting pathology-associated ChEs.

Heart Rate Variability, Microvascular Dysfunction, and Inflammation: Exploring the Potential of taVNS in Managing Heart Failure in Type 2 Diabetes Mellitus

Patients with type 2 diabetes mellitus (T2DM) predominantly experience mortality due to cardiovascular diseases (CVD), particularly in low- and middle-income nations. Among these, heart failure (HF) is the most severe cardiovascular complication in terms of prognosis and management. Despite advancements in individualized glycemic control and cardiovascular risk management, including the development of novel glucose- and lipid-lowering agents, the prevalence of HF in T2DM patients remains persistently high. This indicates that factors beyond hyperglycemia significantly contribute to the heightened risk of HF associated with T2DM. This review examines critical factors influencing CVD risk in T2DM, particularly the roles of reduced heart rate variability (HRV), a marker of autonomic dysfunction, and chronic inflammation, both of which play pivotal roles in HF pathogenesis. Recent evidence highlights the potential of vagus nerve activation to modulate these risk factors, underscoring its capacity to reduce T2DM-related cardiovascular complications. Specifically, we discuss the therapeutic promise of transcutaneous auricular vagus nerve stimulation (taVNS) as a non-invasive intervention to enhance vagal tone, decrease systemic inflammation, and improve cardiovascular outcomes in T2DM. By addressing the interplay among HRV, microvascular disease, and inflammation, this review provides a comprehensive perspective on the potential utility of taVNS in managing HF in T2DM.

Interleukin 18 and the brain: neuronal functions, neuronal survival and psycho-neuro-immunology during stress

Interleukin 18 (IL-18) is a pleiotropic cytokine that regulates peripheral innate and adaptive immune response and is also expressed in the brain. Here, we summarize the current knowledge on the biology of IL-18 in the brain and the efforts to determine its significance concerning neurological and psychiatric conditions. The picture that emerges is that of a heavily regulated molecule that can contribute to neuroinflammatory-mediated neuronal survival but can also serve as a neuromodulator that affects behaviour. We also summarize evidence showing how the brain can control the synthesis of peripheral IL-18 during stress by hormonal and neuronal signalling, regulating tissue-specific promoter usage. We discuss how this may represent one of the mechanisms by which the brain affects immune functions and what its implications are when considering IL-18 as a biomarker of psychiatric conditions.

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.

Immunity and neuroinflammation in early stages of life and epilepsy

The immune system is crucial for the correct brain development, and recent findings also point toward central control of immune response. As the immune system is not fully developed at birth, the early years become an important window for infections and for the development of epilepsy. Both central and even peripheral inflammation may impact brain function, promoting opening of the blood-brain/blood and cerebrospinal barriers and allowing entry of immune cells and cytokines, which in turn may affect neuron function and connections. The resident brain immune cells, microglia, besides providing protection, also affect neurons, myelination, and astrocyte function. They may, via the complement system, remove synapses, both physiologically and pathologically. After seizures during development, activated microglia releases proinflammatory molecules, which are detrimental for neurons, and inhibition of microglial activation shows promising antiepileptogenic effects. In addition to cytokines, seizures and excessive excitability stimulate calpain 2 expression, which can promote neuron loss and contribute to amplification of inflammatory responses via stimulation of proinflammatory cytokines. In summary, the immature immune system during postnatal early life may be an important target for the development of long-desired antiepileptogenic drugs.

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.

α-Bisabolol alleviates doxorubicin-induced cognitive dysfunction in rats via enhancing the hippocampal BDNF/TrKB signaling and inhibiting neuroinflammation

Chemofog is a serious sequela commonly manifested among cancer patients receiving doxorubicin (DOX) chemotherapy. Our goal was to explore the abrogative action of α-Bisabolol (BISA), a phytochemical sesquiterpene, against DOX-induced cognitive deficit. Rats were allocated into 5 groups: Group I: control; Group II received BISA orally (100 mg/kg/day for 4 weeks); Group III received DOX (2 mg/kg/week/i.p.) for 4 weeks; Groups IV and V were administered BISA orally at 50 and 100 mg/kg, respectively plus DOX, i. p. Results: 1) BISA attenuated DOX-induced chemofog as shown in memory-related behavioral tests. 2) BISA restored the hippocampal histological structure and redox homeostasis via diminishing MDA content and upregulating Nrf2 and HO-1 genes. 3) BISA mitigated DOX-induced neuroinflammation through reducing NF-kB, TNF-α, IL-6, IL-1β, and GFAP expressions. 4) BISA repressed the hippocampal apoptosis via downregulating Bax gene and upregulating Bcl-2 gene. 5) BISA enhanced the synaptic plasticity by activating the BDNF/TrKB signaling and increasing the levels of neurotransmitters that enhance memory, i.e., ACh, 5-HT, and DA. BISA at 100 mg/kg/day exerted a better neuroprotection than BISA at 50 mg/kg/day. Thus, BISA may protect cancer patients from cognitive disorders caused by DOX.

Acetylcholine-loaded nanoparticles protect against doxorubicin-induced toxicity inin vitrocardiac spheroids

Doxorubicin (DOX) is widely used in chemotherapy, yet it significantly contributes to heart failure-associated death. Acetylcholine (ACh) is cardioprotective by enhancing heart rate variability and reducing mitochondrial dysfunction and inflammation. Nonetheless, the protective role of ACh in countering DOX-induced cardiotoxicity (DIC) remains underexplored as current approaches to increasing ACh levels are invasive and unsafe for patients. In this study, we explore the protective effects of ACh against DIC through three distinct ACh administration strategies: (i) freely-suspended 100µM ACh; (ii) ACh-producing cholinergic neurons (CNs); or (iii) ACh-loaded nanoparticles (ACh-NPs). These are tested inin vitrocardiac spheroids (CSs), which have previously been shown to approximate the complex DIC. We assess ACh's protective effects by measuring the toxicity ratio (cell death/viability), contractile activity, gene expression changes via qPCR and nitric oxide (NO) signaling. Our findings show that ACh effectively attenuates DOX-induced cell death and contractile dysfunction. ACh also counteracts the DOX-induced downregulation of genes controlling myocardial fibrosis, endothelial and cardiomyocyte dysfunction, and autonomic dysregulation. ACh cardioprotection against DOX is dependent on NO signaling in endothelial cells but not in cardiac myocytes or fibroblasts. Altogether, this study shows for the first time that elevating ACh levels showed a promising therapeutic approach for preventing DIC.

Sour neuronal signalling attenuates macrophage-mediated liver injury

BACKGROUND & AIMS

Liver injury, a common pathophysiological basis of various liver diseases, is associated with inflammation. Hepatic nerves regulate inflammation. However, the specific signals that trigger inflammation and methods to treat inflammation by targeting nerves remain unknown.

METHODS

First, we constructed an animal model to detect the effect of sour stimuli on liver ischaemia-reperfusion injury (IRI) in mice. Next, we analysed the altered gene expression of neurons during liver IRI by single-cell sequencing. In addition, we explored the effect of sour stimuli on liver IRI in mice. Finally, we designed clinical trials to explore the effect of sour stimuli on liver IRI during hepatectomy.

RESULTS

In this study, single-cell sequencing data from the liver and celiac ganglion showed that TAFA2 was induced in neurones during liver IRI, whereas sour stimuli decreased TAFA2 production and liver injury. In vivo studies showed that TAFA2 ablation and specific knockdown in neurones reduce liver injury. Using FLAG-tagged TAFA2, we found that TAFA2 interacted with chemokine C-C-motif receptor 2 (CCR2) and promoted macrophage activation, consistent with RNA sequencing data showing that TAFA2 induced the expression of inflammatory genes in wild-type macrophages, but not in Ccr2 knockout macrophages. Moreover, patients exposed to sour stimuli exhibited less severe liver IRI during hepatectomy.

CONCLUSIONS

Our results reveal a neuroimmune interaction in which neurone-derived TAFA2 recruits CCR2+ macrophages to the liver and triggers liver injury, which is at least partly reduced by nerve signalling in response to sour stimuli, i.e. consumption of acidic substances. Our findings provide new insights into the brain-liver axis and potential therapeutic approaches for liver injury.

IMPACT AND IMPLICATIONS

In this study, we demonstrated that sour stimuli, which are related to consumption of acidic foods, are at least partly responsible for reducing human and mouse liver ischaemia-reperfusion injury (IRI), and we confirmed the important role of the brain-liver axis in liver IRI. In this study, we found that the brain-liver axis increases liver IRI through the secretion of TAFA2 protein. TAFA2 mediated liver IRI through the recruitment and activation of macrophages via the receptor CCR2. Additionally, TAFA2 was shown to induce a proinflammatory transcriptional profile in macrophages. Our findings provide new insights into the brain-liver axis and uncover a potential therapeutic strategy to reduce IRI.

CLINICAL TRIAL NUMBER

This clinical trial was registered with the Chinese Clinical Trial Registry (ChiCTR2400088096).

Fighting off a gut feeling: A gut-brain-lung neuroimmune circuit

In this issue of Neuron, Chen et al. identify a postprandial neuroimmune axis by which feeding-induced stimulation of the gastrointestinal tract triggers type 2 immunity in the lung.1 This study hints that there are likely distinct sensory and motor circuits coordinated by the brain across different tissues to drive neuroinflammation.

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.

Activation of α7nAch receptors ameliorates α-synuclein pathology in the brain and gut of a subacute MPTP mouse model of Parkinson's disease

Parkinson's disease (PD) is a neurological disorder that causes a gradual decrease in mobility. Abnormal α-synuclein (α-syn) levels and aggregation contribute to PD development. The dissemination of α-synuclein pathology via the gut-brain axis has emerged as a critical aspect in α-synucleinopathies, including PD. Recently, α7 nicotinic acetylcholine receptor (α7nAchR) agonists have been proposed as promising agents for treating PD, owing to their biological properties such as anti-inflammatory effects. This study aims to investigate whether activation of α7nAchR improves α-synuclein pathology in the brain and gut of a mouse model of PD. We found that α7nAchR agonists, GTS-21 and PNU-282987, induced behavioral recovery and improved nigrostriatal dopaminergic neurotransmission in a subacute MPTP mouse model of PD. In addition, GTS-21 and PNU-282987 facilitated α-syn clearance in the brain and distal colon, as evidenced by a considerable reduction in the accumulation of pathogenic forms of α-syn. Accordingly, GTS-21 and PNU-282987 were found to promote the AMPK-mTOR autophagy signaling pathway. Furthermore, GTS-21 and PNU-282987 exerted anti-inflammatory effects, reducing the levels of proinflammatory mediators such as inducible nitric oxide synthase, interleukin-6, and tumor necrosis factor-α in both the brain and gut. To validate the specific effects of α7nAchR agonists, subacute MPTP mice were pretreated with methyllycaconitine (MLA), a selective α7nAchR antagonist before GTS-21 administration. Pretreatment with MLA abolished the GTS-21-elicited behavioral recovery, α-syn clearance, and anti-inflammatory effects in the brain and gut. Therefore, α7nAchR activation may be a potential candidate strategy for the treatment of PD by altering α-syn aggregation in the brain and gut.

Dynamic human gut microbiome and immune shifts during an immersive psychosocial intervention program

BACKGROUND

Although depression is a leading cause of disability worldwide, the pathophysiological mechanisms underlying this disorder-particularly those involving the gut microbiome-are poorly understood.

METHOD

To investigate, we conducted a community-based observational study to explore complex associations between changes in the gut microbiome, cytokine levels, and depression symptoms in 51 participants (Mage = 49.56, SD = 13.31) receiving an immersive psychosocial intervention. A total of 142 multi-omics samples were collected from participants before, during, and three months after the nine-day inquiry-based stress reduction program.

RESULTS

Results revealed that depression was associated with both an increased presence of putatively pathogenic bacteria and reduced microbial beta-diversity. Following the intervention, we observed reductions in neuroinflammatory cytokines and improvements in several mental health indicators. Interestingly, participants with a Prevotella-dominant microbiome showed milder symptoms when depressed, along with a more resilient microbiome and more favorable inflammatory cytokine profile, including reduced levels of CXCL-1.

CONCLUSIONS

These findings reveal a potentially protective link between the Prevotella-dominant microbiome and depression, as evidenced by a reduced pro-inflammatory environment and fewer depressive symptoms. These insights, coupled with observed improvements in neuroinflammatory markers and mental health from the intervention, may highlight potential avenues for microbiome-targeted therapies for managing depression.

Vagus nerve stimulation: A targeted approach for reducing tissue-specific ischemic reperfusion injury

Vagus Nerve Stimulation (VNS), a neuromodulation technique of applying controlled electrical impulses to the vagus nerve, has now emerged as a potential therapeutic approach for ischemia-reperfusion insults. It provides a pivotal link in improving functional outcomes for the central nervous system and multiple target organs affected by ischemia-reperfusion injury (I/RI). Reduced blood flow during ischemia and subsequent resumption of blood supply during reperfusion to the tissue compromises cellular health because of the combination of mitochondrial dysfunction, oxidative stress, cytokine release, inflammation, apoptosis, intracellular calcium overload, and endoplasmic reticulum stress, which ultimately leads to cell death and irreversible tissue damage. Furthermore, inflammation and apoptosis also play critical roles in the acute progression of ischemic injury pathology. Emerging evidence indicates that VNS in I/RI may act in an anti-inflammatory capacity, reducing oxidative stress and apoptosis, while also improving endothelial and mitochondrial function leading to reduced infarct sizes and cytoprotection in skeletal muscle, gastrointestinal tract, liver, kidney, lung, heart, and brain tissue. In this review, we attempt to shed light on the mechanistic links between tissue-specific damage following I/RI and the therapeutic approach of VNS in attenuating damage, considering both direct and remote I/RI scenarios. Thus, we want to advance the understanding of VNS that could further warrant its clinical implementation, especially as a treatment for I/RI.

Chronic Cr(VI) exposure-induced biotoxicity involved in liver microbiota-gut axis disruption in Phoxinus lagowskii Dybowski based on multi-omics technologies

Cr(VI) is widely used in industry and has high toxicity, making it one of the most common environmental pollutants. Long-term exposure to Cr(VI) can cause metabolic disorders and tissue damage. However, the effects of Cr(VI) on liver and gut microbes in fish have rarely been reported. In this study, 240 fish were randomly divided into 3 groups: the control group, low-dose Cr(VI) group (0.5 mg/L), and high-dose Cr(VI) group (2 mg/L). The mechanism by which Cr(VI) affects the enterohepatic axis of common carp was elucidated via multiomic analysis, serology, histomorphology, and physiological and biochemical indices. The results revealed that Cr(VI) stress led to hepatocyte damage, nuclear lysis, inflammatory cell infiltration, and vacuolated degeneration. The structure of the intestinal villi was severely damaged, and the length and width of the intestinal villi were significantly reduced. We also found that the accumulation of Cr(VI) in tissues increased in a concentration-dependent manner, and the content of Cr(VI) in each tissue increased in the order of gut > gill > liver > muscle. Multiple omics studies have revealed that chronic Cr(VI) stress leads to disturbances in the intestinal flora, with a significant reduction in the abundance of the beneficial bacterium Akkermansia and a significant increase in the abundance of the harmful bacterium Escherichia/Shigella. Intestinal injury and dysbiosis lead to an increase in blood LPS levels, further inducing metabolic disorders in the liver. The metabolites in the liver, including geniposide, leucine, C17 sphingosine, and 9,10-DiHODE, were significantly increased, whereas the beneficial metabolites, such as carnitine propionate and palmitoyl ethanolamide, were significantly reduced. In conclusion, our results suggest that chronic Cr(VI) stress leads to disturbances in gut microbial homeostasis and disturbed fatty acid and amino acid metabolism in the liver. LPS released into the bloodstream reaches the liver through the portal circulation, further exacerbating Cr(VI) stress-induced hepatotoxicity. This study revealed the mechanism of Cr(VI) toxicity to the liver-microbiota-gut axis of common carp. Our study provides new insights into the effects of Cr(VI) on the liver-microbiota-gut axis.

Effects of Auricular Stimulation on Inflammatory Parameters: Results of a Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

The number of randomized controlled trials (RCTs) using auricular stimulation (AS) techniques, such as transauricular vagus nerve stimulation, auricular electrostimulation, auricular acupuncture, and acupressure in experimental and clinical settings has increased markedly over the last three decades. This systematic review evaluates the effects of AS on biomarkers of inflammation and stress responses.

MATERIALS AND METHODS

The following data bases were searched: MEDLINE (PubMed), EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), ISI Web of Science, and Scopus Data base. Data collection and analysis were conducted independently by two reviewers. Quality and risk assessments of the included studies were performed, and a meta-analysis of the effects of the most frequently assessed biomarkers was conducted using RevMan statistical software.

RESULTS

A total of 1122 patients and healthy volunteers from 27 RCTs were included in this systematic review; 81% of the participants were female, with a median age of 51 years. Pooled data of 18 studies showed a significant effect of AS regarding a reduction of serum C-reactive protein, tumor necrosis factor-α, interleukin (IL)-6, and IL-10. Although IL-4, IL1β, cortisol, substance P and calcitonin gene-related peptide, and adrenocorticotropic hormone did not show any changes, salivary amylase increased under AS.

CONCLUSIONS

The influence of inflammatory cytokines seems to be mediated by AS. More research is needed to investigate the effects of AS on the immunologic system in addition to its clinical significance in high-quality RCT.

Stimulation of TRPV1+ peripheral somatosensory nerves suppress inflammation via the somato-autonomic reflex

Excessive inflammation causes a wide range of diseases. Here, we found that stimulating TRPV1+ nerves at the nape activated the nucleus of the solitary tract and C1 neurons in the brainstem via the somatosensory afferent pathway, and rapidly induced the secretion of corticosterone, and drove the vagal-adrenal axis to release serum catecholamines, and activated the autonomic-splenic reflex to suppress cytokine production. RNA sequencing (RNA-seq) analysis revealed that stimulating TRPV1+ nerves significantly changed the expression of genes enriched in multiple pathways related to the inflammatory response in the spleen under pathological and normal physiological conditions. TRPV1 agonist lost these anti-inflammatory effects in trpv1ko mice. Our study revealed a neural circuit that stimulating TRPV1+ somatosensory afferents at the nape could concurrently drive the sympathetic and parasympathetic efferents to synergistically induce anti-inflammatory effects. Furthermore, stimulation of TRPV1+ peripheral sensory afferents in specific body regions is an efficient therapeutic approach to treat inflammatory diseases.

Esmolol upregulates the α7 nAChR/STAT3/NF-κB pathway by decreasing the ubiquitin and increasing the ChAT+CD4+ T lymphocyte to alleviate inflammation in septic cardiomyopathy

Esmolol has been demonstrated to mitigate inflammation damage and T lymphocyte apoptosis in septic cardiomyopathy. It has been established that the activation of α7 nicotinic acetylcholine receptor (nAChR) by cluster of differentiation 4(CD4) + T lymphocytes expressing choline acetyltransferase (ChAT) can prevent excessive inflammation and reduce splenocyte apoptosis in septic cardiomyopathy. Given the similar anti-inflammatory effects, we hypothesized that esmolol might be associated with α7 nAChR and thereby exert its cardioprotective functions. In the cecal ligation puncture (CLP)-induced rat septic cardiomyopathy model, esmolol was found to attenuate myocardial injury as evidenced by Hematoxylin and Eosin (HE) staining, terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay, and the reduced concentration of interleukin (IL)-1, IL-6, and Tumor Necrosis Factor (TNF)-α detected by enzyme-linked immunosorbent assay (ELISA). Western blotting (WB) revealed that esmolol enhanced the expression of α7 nAChR, elevated the level of Phosphorylated-Signal transducer and activator of transcription 3 (P-STAT3)/STAT3, and decreased the level of Nuclear factor-κB (NF-κB), which led to the reduction of plasma IL-1, IL-6, and TNF-α. Methyl lycaconitine Citrate (MLA, an α7 nAChR inhibitor) suppressed the level of P-STAT3/STAT3, while stattic (a STAT3 inhibitor) inhibited the level of P-STAT3/STAT3 and up-regulated the expression of NF-κB. Real-time quantitative PCR (RT-qPCR) results indicated no significant difference in the mRNA level of α7 nAChR, but immunofluorescence and WB results verified the upregulation of α7 nAChR by esmolol and the reduction of ubiquitin induced by esmolol. In the spleen, esmolol decreased splenocyte apoptosis and increased the expression of α7 nAChR as shown by immunofluorescence. In isolated CD4+ T cells obtained through magnetic cell separation, esmolol enhanced the expression of ChAT mRNA. In conclusion, esmolol upregulates α7 nAChR by decreasing ubiquitin and increasing ChAT+CD4+ T lymphocytes and then increases the P-STAT3/STAT3 which inhibits NF-κB thus alleviating inflammation in septic cardiomyopathy.