Vagus Nerve Stimulation Protects Enterocyte Glycocalyx After Hemorrhagic Shock Via the Cholinergic Anti-Inflammatory Pathway

TRAUMA AND THE ENTEROCYTE: DISTURBANCE OF COMMUNICATION AND DELINEATION

ABSTRACT

The enterocyte as major building stone of the intestinal barrier plays a central role in maintaining cellular homeostasis and mediating host-environment interactions. Trauma, whether direct or remote, disrupts enterocyte function through complex mechanisms including impaired oxygen delivery, disturbed intercellular communication, and compromised nutrient uptake and metabolite clearance. These changes may lead to barrier dysfunction and altered repair mechanisms, facilitating systemic inflammation and remote organ injury. The failure of communication pathways-both within enterocytes and across epithelial networks-undermines coordinated responses to injury. Understanding these multifaceted perturbations reveals the enterocyte not merely as a passive victim but as an active participant in trauma-induced pathology. Emerging therapeutic strategies focus on enhancing mucosal repair via sealing agents, promoting epithelial proliferation, and restoring metabolic and signaling homeostasis. This review delineates the dynamic response of the enterocyte to trauma, highlighting opportunities for targeted interventions aimed at restoring intestinal integrity and function.

Neuropsychological Insights Into Child Survival: Possible Protective Dissociation During Prolonged Entrapment After a Turkish Earthquake

BACKGROUND Earthquakes and other catastrophic events can lead to conditions of being trapped under the rubble, which can cause minor-major health consequences. One of the most challenging issues in entrapment is the need to rescue people as fast as possible. A related issue for rescue forces is how long to continue searching survivors. Indeed, sometimes victims survive longer than expected. The cases described below led us to postulate that certain adverse psychological effects of being trapped under the rubble may be beneficial for survival in such extreme situations. CASE REPORT In this article, we report two cases of children who were rescued from under the rubble following the earthquake in Turkey in February 2023. The children were rescued approximately one week after the earthquake, exhibiting symptoms that could be understood as dissociation. We bring converging neuropsychological and neurophysiological scientific evidence which enables us to propose that dissociation-related imagination together with excessive sleep may have increased vagal nerve activity. Vagal activity in turn may have helped to reduce risk of infections and inflammation, and possibly increased the chance of survival. CONCLUSIONS Though impossible to measure and prove in such extreme contexts, we propose a plausible psychobiological mechanism for those children’s symptoms and relatively long survival under entrapment. While only a speculation, dissociation might have been protective in such conditions. We discuss the limitations of these reports and the speculative mechanisms, and provide  further implications for policy.

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.

Intestinal epithelial glycocalyx and intestinal disease

With the continuous research on glycobiology, more and more diseases are found to be associated with the glycocalyx. Glycocalyx can be categorized as endothelial glycocalyx and epithelial glycocalyx. Past studies mostly target endothelial glycocalyx, and this review focuses on the structure and function of intestinal epithelial glycocalyx, its degradation mechanism and biological relevance to different diseases of the intestinal tract, as well as the targeted delivery of drugs to organs by nanoparticle libraries mimicking the glycocalyx, in order to provide a theoretical basis for the study of potential diagnostic markers and therapeutic targets of intestinal epithelial glycocalyx in intestinal diseases.

Research progress on intestinal microbiota regulating cognitive function through the gut-brain axis

The intestinal microbiota community is a fundamental component of the human body and plays a significant regulatory role in maintaining overall health and in the management disease states.The intestinal microbiota-gut-brain axis represents a vital connection in the cognitive regulation of the central nervous system by the intestinal microbiota.The impact of intestinal microbiota on cognitive function is hypothesized to manifest through both the nervous system and circulatory system. Imbalances in intestinal microbiota during the perioperative period could potentially contribute to perioperative neurocognitive dysfunction. This article concentrates on a review of existing literature to explore the potential influence of intestinal microbiota on brain and cognitive functions via the nervous and circulatory systems.Additionally, it summarizes recent findings on the impact of perioperative intestinal dysbacteriosis on perioperative neurocognitive dysfunction and suggests novel approaches for prevention and treatment of this condition.

Computational biology-based study of the molecular mechanism of spermidine amelioration of acute pancreatitis

Acute pancreatitis (AP) is an acute inflammatory gastrointestinal disease, the mortality and morbility of which has been on the increase in the past years. Spermidine, a natural polyamine, has a wide range of pharmacological effects including anti-inflammation, antioxidation, anti-aging, and anti-tumorigenic. This study aimed to investigate the reliable targets and molecular mechanisms of spermidine in treating AP. By employing computational biology methods including network pharmacology, molecular docking, and molecular dynamics (MD) simulations, we explored the potential targets of spermidine in improving AP with dietary supplementation. The computational biology results revealed that spermidine had high degrees (degree: 18, betweenness: 38.91; degree: 18, betweenness: 206.41) and stable binding free energy (ΔGbind: - 12.81 ± 0.55 kcal/mol, - 15.00 ± 1.00 kcal/mol) with acetylcholinesterase (AchE) and serotonin transporter (5-HTT). Experimental validation demonstrates that spermidine treatment could reduce the necrosis and AchE activity in pancreatic acinar cells. Cellular thermal shift assay (CETSA) results revealed that spermidine could bind to and stabilize the 5-HTT protein in acinar cells. Moreover, spermidine treatment impeded the rise of the expression of 5-HTT in pancreatic tissues of caerulein induced acute pancreatitis mice. In conclusion, serotonin transporter might be a reliable target of spermidine in treating AP. This study provides new idea for the exploration of potential targets of natural compounds.

Transcutaneous vagus nerve stimulation: a new strategy for Alzheimer's disease intervention through the brain-gut-microbiota axis?

Transcutaneous vagus nerve stimulation (tVNS) is an emerging non-invasive technique designed to stimulate branches of the vagus nerve distributed over the body surface. Studies suggest a correlation between the brain-gut-microbiota (BGM) axis and the pathogenesis of Alzheimer's disease (AD). The BGM axis represents a complex bidirectional communication system, with the vagus nerve being a crucial component. Therefore, non-invasive electrical stimulation of the vagus nerve might have the potential to modify-most of the time probably in a non-physiological way-the signal transmission within the BGM axis, potentially influencing the progression or symptoms of AD. This review explores the interaction between percutaneous vagus nerve stimulation and the BGM axis, emphasizing its potential effects on AD. It examines various aspects, such as specific brain regions, gut microbiota composition, maintenance of intestinal environmental homeostasis, inflammatory responses, brain plasticity, and hypothalamic-pituitary-adrenal (HPA) axis regulation. The review suggests that tVNS could serve as an effective strategy to modulate the BGM axis and potentially intervene in the progression or treatment of Alzheimer's disease in the future.

Resuscitating the Endothelial Glycocalyx in Trauma and Hemorrhagic Shock

The endothelium is lined by a protective mesh of proteins and carbohydrates called the endothelial glycocalyx (EG). This layer creates a negatively charged gel-like barrier between the vascular environment and the surface of the endothelial cell. When intact the EG serves multiple functions, including mechanotransduction, cell signaling, regulation of permeability and fluid exchange across the microvasculature, and management of cell-cell interactions. In trauma and/or hemorrhagic shock, the glycocalyx is broken down, resulting in the shedding of its individual components. The shedding of the EG is associated with increased systemic inflammation, microvascular permeability, and flow-induced vasodilation, leading to further physiologic derangements. Animal and human studies have shown that the greater the severity of the injury, the greater the degree of shedding, which is associated with poor patient outcomes. Additional studies have shown that prioritizing certain resuscitation fluids, such as plasma, cryoprecipitate, and whole blood over crystalloid shows improved outcomes in hemorrhaging patients, potentially through a decrease in EG shedding impacting downstream signaling. The purpose of the following paragraphs is to briefly describe the EG, review the impact of EG shedding and hemorrhagic shock, and begin entertaining the notion of directed resuscitation. Directed resuscitation emphasizes transitioning from macroscopic 1:1 resuscitation to efforts that focus on minimizing EG shedding and maximizing its reconstitution.

The protective effect of pericytes on vascular permeability after hemorrhagic shock and their relationship with Cx43

Vascular hyperpermeability is a complication of hemorrhagic shock. Pericytes (PCs) are a group of mural cells surrounded by microvessels that are located on the basolateral side of the endothelium. Previous studies have shown that damage to PCs contributes to the occurrence of many diseases such as diabetic retinopathy and myocardial infarction. Whether PCs can protect the vascular barrier function following hemorrhagic shock and the underlying mechanisms are unknown. A hemorrhagic shock rat model, Cx43 vascular endothelial cell (VEC)-specific knockdown mice, and VECs were used to investigate the role of PCs in vascular barrier function and their relationship with Cx43. The results showed that following hemorrhagic shock, the number of PCs in the microvessels was significantly decreased and was negatively associated with an increase in pulmonary and mesenteric vascular permeability. Exogenous infusion of PCs (106 cells per rat) colonized the microvessels and improved pulmonary and mesenteric vascular barrier function. Upregulation of Cx43 in PCs significantly increased the number of PCs colonizing the pulmonary vessels. In contrast, downregulation of Cx43 expression in PCs or knockout of Cx43 in VECs (Cx43 KO mice) significantly reduced PC colonization in pulmonary vessels in vivo and reduced direct contact formation between PCs and VECs in vitro. It has been suggested that PCs have an important protective effect on vascular barrier function in pulmonary and peripheral vessels following hemorrhagic shock. Cx43 plays an important role in the colonization of exogenous PCs in the microvessels. This finding provides a potential new shock treatment measure.

Innate immunity and immunotherapy for hemorrhagic shock

Hemorrhagic shock (HS) is a shock result of hypovolemic injury, in which the innate immune response plays a central role in the pathophysiology ofthe severe complications and organ injury in surviving patients. During the development of HS, innate immunity acts as the first line of defense, mediating a rapid response to pathogens or danger signals through pattern recognition receptors. The early and exaggerated activation of innate immunity, which is widespread in patients with HS, results in systemic inflammation, cytokine storm, and excessive activation of complement factors and innate immune cells, comprised of type II innate lymphoid cells, CD4⁺ T cells, natural killer cells, eosinophils, basophils, macrophages, neutrophils, and dendritic cells. Recently, compelling evidence focusing on the innate immune regulation in preclinical and clinical studies promises new treatment avenues to reverse or minimize HS-induced tissue injury, organ dysfunction, and ultimately mortality. In this review, we first discuss the innate immune response involved in HS injury, and then systematically detail the cutting-edge therapeutic strategies in the past decade regarding the innate immune regulation in this field; these strategies include the use of mesenchymal stem cells, exosomes, genetic approaches, antibody therapy, small molecule inhibitors, natural medicine, mesenteric lymph drainage, vagus nerve stimulation, hormones, glycoproteins, and others. We also reviewed the available clinical studies on immune regulation for treating HS and assessed the potential of immune regulation concerning a translation from basic research to clinical practice. Combining therapeutic strategies with an improved understanding of how the innate immune system responds to HS could help to identify and develop targeted therapeutic modalities that mitigate severe organ dysfunction, improve patient outcomes, and reduce mortality due to HS injury.

Neuromodulation Strategies to Reduce Inflammation and Improve Lung Complications in COVID-19 Patients

Since the outbreak of the COVID-19 pandemic, races across academia and industry have been initiated to identify and develop disease modifying or preventative therapeutic strategies has been initiated. The primary focus has been on pharmacological treatment of the immune and respiratory system and the development of a vaccine. The hyperinflammatory state ("cytokine storm") observed in many cases of COVID-19 indicates a prognostically negative disease progression that may lead to respiratory distress, multiple organ failure, shock, and death. Many critically ill patients continue to be at risk for significant, long-lasting morbidity or mortality. The human immune and respiratory systems are heavily regulated by the central nervous system, and intervention in the signaling of these neural pathways may permit targeted therapeutic control of excessive inflammation and pulmonary bronchoconstriction. Several technologies, both invasive and non-invasive, are available and approved for clinical use, but have not been extensively studied in treatment of the cytokine storm in COVID-19 patients. This manuscript provides an overview of the role of the nervous system in inflammation and respiration, the current understanding of neuromodulatory techniques from preclinical and clinical studies and provides a rationale for testing non-invasive neuromodulation to modulate acute systemic inflammation and respiratory dysfunction caused by SARS-CoV-2 and potentially other pathogens. The authors of this manuscript have co-founded the International Consortium on Neuromodulation for COVID-19 to advocate for and support studies of these technologies in the current coronavirus pandemic.

Mucosal Plasma Cell Activation and Proximity to Nerve Fibres Are Associated with Glycocalyx Reduction in Diarrhoea-Predominant Irritable Bowel Syndrome: Jejunal Barrier Alterations Underlying Clinical Manifestations

Irritable bowel syndrome (IBS) is a disorder of brain-gut interaction characterised by abdominal pain and changes in bowel habits. In the diarrhoea subtype (IBS-D), altered epithelial barrier and mucosal immune activation are associated with clinical manifestations. We aimed to further evaluate plasma cells and epithelial integrity to gain understanding of IBS-D pathophysiology. One mucosal jejunal biopsy and one stool sample were obtained from healthy controls and IBS-D patients. Gastrointestinal symptoms, stress, and depression scores were recorded. In the jejunal mucosa, RNAseq and gene set enrichment analyses were performed. A morphometric analysis by electron microscopy quantified plasma cell activation and proximity to enteric nerves and glycocalyx thickness. Immunoglobulins concentration was assessed in the stool. IBS-D patients showed differential expression of humoral pathways compared to controls. Activation and proximity of plasma cells to nerves and IgG concentration were also higher in IBS-D. Glycocalyx thickness was lower in IBS-D compared to controls, and this reduction correlated with plasma cell activation, proximity to nerves, and clinical symptoms. These results support humoral activity and loss of epithelial integrity as important contributors to gut dysfunction and clinical manifestations in IBS-D. Additional studies are needed to identify the triggers of these alterations to better define IBS-D pathophysiology.