Neural immunoregulation: emerging roles for nerves in immune homeostasis and disease

Navigating the blurred path of mixed neuroimmune signaling

Evolution has created complex mechanisms to sense environmental danger and protect tissues, with the nervous and immune systems playing pivotal roles. These systems work together, coordinating local and systemic reflexes to restore homeostasis in response to tissue injury and infection. By sharing receptors and ligands, they influence the pathogenesis of various diseases. Recently, a less-explored aspect of neuroimmune communication has emerged: the release of neuropeptides from immune cells and cytokines/chemokines from sensory neurons. This article reviews evidence of this unique neuroimmune interplay and its impact on the development of allergy, inflammation, itch, and pain. We highlight the effects of this neuroimmune signaling on vital processes such as host defense, tissue repair, and inflammation resolution, providing avenues for exploration of the underlying mechanisms and therapeutic potential of this signaling.

The neuropeptide substance P/neurokinin-1 receptor system and diabetes: From mechanism to therapy

Diabetes is a significant public health issue known as the world's fastest-growing disease condition. It is characterized by persistent hyperglycemia and subsequent chronic complications leading to organ dysfunction and, ultimately, the failure of target organs. Substance P (SP) is an undecapeptide that belongs to the family of tachykinin (TK) peptides. The SP-mediated activation of the neurokinin 1 receptor (NK1R) regulates many pathophysiological processes in the body. There is also a relation between the SP/NK1R system and diabetic processes. Importantly, deregulated expression of SP has been reported in diabetes and diabetes-associated chronic complications. SP can induce both diabetogenic and antidiabetogenic effects and thus affect the pathology of diabetes destructively or protectively. Here, we review the current knowledge of the functional relevance of the SP/NK1R system in diabetes pathogenesis and its exploitation for diabetes therapy. A comprehensive understanding of the role of the SP/NK1R system in diabetes is expected to shed further light on developing new therapeutic possibilities for diabetes and its associated chronic conditions.

Expression of the Antimicrobial Peptide Piscidin 1 and Neuropeptides in Fish Gill and Skin: A Potential Participation in Neuro-Immune Interaction

Antimicrobial peptides (AMPs) are found widespread in nature and possess antimicrobial and immunomodulatory activities. Due to their multifunctional properties, these peptides are a focus of growing body of interest and have been characterized in several fish species. Due to their similarities in amino-acid composition and amphipathic design, it has been suggested that neuropeptides may be directly involved in the innate immune response against pathogen intruders. In this review, we report the molecular characterization of the fish-specific AMP piscidin1, the production of an antibody raised against this peptide and the immunohistochemical identification of this peptide and enkephalins in the neuroepithelial cells (NECs) in the gill of several teleost fish species living in different habitats. In spite of the abundant literature on Piscidin1, the biological role of this peptide in fish visceral organs remains poorly explored, as well as the role of the neuropeptides in neuroimmune interaction in fish. The NECs, by their role as sensors of hypoxia changes in the external environments, in combination with their endocrine nature and secretion of immunomodulatory substances would influence various types of immune cells that contain piscidin, such as mast cells and eosinophils, both showing interaction with the nervous system. The discovery of piscidins in the gill and skin, their diversity and their role in the regulation of immune response will lead to better selection of these immunomodulatory molecules as drug targets to retain antimicrobial barrier function and for aquaculture therapy in the future.

Homeostatic and endocrine responses as the basis for systemic therapy with medical gases: ozone, xenon and molecular hydrogen

Among medical gases, including gases used therapeutically, this review discusses the comparative physiological activity of three gases - ozone (O3), xenon (Xe) and molecular hydrogen (H2), which together form representatives of three types of substances - typical oxidizing, inert, and typical reducing agents. Upon analysis of published and proprietary data, we concluded that these three medical gases can manipulate the neuroendocrine system, by modulating the production or release of hormones via the hypothalamic-pituitary-adrenal, hypothalamic-pituitary-thyroid, hypothalamic-pituitary-gonadal axes, or the gastrointestinal pathway. With repeated administration of the gases over time, these modulations become a predictable consequence of conditioned homeostatic reflexes, resulting in regulation of physiological activity. For example, the regular activation of the unconditioned defense reflex in response to repeated intoxication by ozone leads to the formation of an anticipatory stable conditioned response, which counteracts the toxic action of O3. The concept of a Pavlovian conditioned reflex (or hormoligosis) is a brief metaphor for the understanding the therapeutic effect of systemic ozone therapy.

Use of Suvorexant and Antipsychotics in the Treatment of Delirium After Infectious Diseases: A Retrospective Study

BACKGROUND

Delirium is often treated on a subjective basis and per the discretion of the attending physician because of a lack of pharmacological evidence in the literature. To address this knowledge gap, we aimed to examine the efficacy of a hypnotic drug, suvorexant, as a therapeutic agent for the treatment of delirium.

METHODS

Fifty-seven patients were targeted. Of the 57 patients, 39 were in the subolexant group, 17 in the antipsychotic group, and 1 was taking antidepressants. The Delirium Rating Scale-Revised 98 was used to evaluate the symptoms of delirium before and 3 and 7 days after drug administration. In addition, the medical history, occurrence of adverse effects, white blood cell count, and C-reactive protein level of participants were examined.

RESULTS

Both drugs exhibited therapeutic effects on delirium, but suvorexant had a more pronounced effect. Furthermore, the suvorexant group exhibited decreased levels of C-reactive protein, suggesting an anti-inflammatory effect. Suvorexant seems to improve the symptoms of inflammation-related delirium without any serious adverse effects, suggesting that it can be explored as a safe treatment option for clinical use in future studies.

CONCLUSIONS

Our findings will be relevant for physicians interested in learning about new pharmacological treatment options and researchers interested in validating our results.

Prospective Randomized Controlled Pilot Study of High-Intensity Lightbox Phototherapy to Prevent ICU-Acquired Delirium Incidence

Background

This study aimed to evaluate the role of disturbed circadian rhythm in potentiating intensive care unit (ICU)-acquired delirium.Previous studies have demonstrated bright light therapy (BLT) as an effective modality to improve sleeping patterns and cognitive function in non-critically ill patients. However, its benefit in the ICU has not been clearly established. In this study, we aimed to evaluate the application of daily high-intensity phototherapy at the bedside to deter ICU delirium incidence and duration.

Methodology

This was a single center, prospective study conducted in ICUs at the Carilion Roanoke Memorial Hospital in Roanoke, VA. Adults patients admitted to the ICU from July 9, 2018 to March 20, 2020 were included in the study. The patients were subjected to 30-minute BLT session (10,000 lux) at the bedside starting at 0700 while in the ICU. Patients were randomized into either the control group (standard hospital lighting) or phototherapy group. Data were analyzed using Wilcoxon rank sum test for continuous variables, Pearson chi-square test for categorical variables, and logistic regression for multivariable analysis that examined significant risk factors for ICU delirium.

Results

Delirium incidence between BLT (18%) and control (17.5%) groups was non-significant. Total number of delirium-free, coma-free days, as determined by Confusion Assessment Method for the ICU, demonstrated no differences between groups with a median of 28 days (p = 0.516). In multivariable analysis, patients with a Sequential Organ Failure Assessment Score >3 also showed no significant change in ICU delirium incidence when provided bedside BLT compared to those with standard hospital lighting (odds ratio: 0.08; 95% confidence interval: 0.002-1.40; p = 0.867).

Conclusions

In this randomized control pilot study, daily morning 10,000 lux BLT of 30-minute duration alone was not associated with a significant decrease in ICU-acquired delirium incidence or duration compared to standard hospital lighting. Future studies should consider a nuanced approach to better elucidate the role of disturbed circadian rhythm in influencing ICU-acquired delirium by not only undertaking BLT during the day but also minimizing nighttime light exposure.

Choline: An Essential Nutrient for Skeletal Muscle

BACKGROUND

Choline is an essential micronutrient with a pivotal role in several metabolic pathways contributing to liver, neurological, and hematological homeostasis. Although choline is commonly administered to improve physical performance, its effects on muscle are still unclear. The aim of this scoping review is to analyze the role of choline on skeletal muscle in terms of biological effects and clinical implications.

METHODS

A technical expert panel (TEP) of 6 medical specialists with expertise in muscle physiology and skeletal muscle disorders performed the review following the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews) model. The TEP planned a research on PubMed selecting "choline" as MeSH (Medical Subject Headings) term adding to PubMed Search Builder the terms "skeletal muscle" and "muscle striated". TEP considered for eligibility articles published in the last 30 years, including original researches, particularly in vitro studies, and animal and clinical studies in the English language.

RESULTS

From the 1239 studies identified, TEP included 14 studies, 3 in vitro, 9 animal, and 2 clinical studies.

CONCLUSIONS

Our scoping review elucidates and summarizes the crucial role of choline in modulating muscle fat metabolism, muscle proteins homeostasis, and the modulation of inflammation and autophagy.

Regulating appetite in broilers for improving body and muscle development - A review

Appetite is the desire for feed and water and the voluntary intake of feed and is an important regulator of livestock productivity and animal health. Economic traits such as growth rate and muscle development (meat deposition) in broilers are directly correlated to appetite. Factors that may influence appetite include environmental factors, such as stress and temperature variation, and animal‐specific factors, such as learning period, eating capacity and preferences. Feed preferences have been reported to be determined in early life, and this period is important in broilers due to their fast growth and relatively short growth trajectories. This may be of importance when contemplating the use of more circular and sustainable feeds and the optimization of appetite for these feeds. The objective of this review was to review the biological mechanisms underlying appetite using data from human, animal and bird models and to consider the option for modulating appetite particularly as it relates to broiler chickens.

Neuro-Immunity Controls Obesity-Induced Pain

The prevalence of obesity skyrocketed over the past decades to become a significant public health problem. Obesity is recognized as a low-grade inflammatory disease and is linked with several comorbidities such as diabetes, circulatory disease, common neurodegenerative diseases, as well as chronic pain. Adipocytes are a major neuroendocrine organ that continually, and systemically, releases pro-inflammatory factors. While the exact mechanisms driving obesity-induced pain remain poorly defined, nociceptor hypersensitivity may result from the systemic state of inflammation characteristic of obesity as well as weight surplus-induced mechanical stress. Obesity and pain also share various genetic mutations, lifestyle risk factors, and metabolic pathways. For instance, fat pads are often found hyper-innervated and rich in immune cell types of multiple origins. These immunocytes release cytokines, amplifying nociceptor function, which, in turn, via locally released neuropeptides, sustain immunocytes' function. Here, we posit that along with mechanical stress stemming from extra weight, the local neuro-immune interplay occurring within the fat pads maintains the state of chronic low-grade inflammation and heightens sensory hypersensitivity. Overall, stopping such harmful neuro-immune crosstalk may constitute a novel pathway to prevent obesity-associated comorbidities, including neuronal hypersensitivity.

Plasma biomarkers of inflammation, coagulation, and brain injury as predictors of delirium duration in older hospitalized patients

Background

Delirium's pathophysiology is poorly understood. We sought to determine if plasma biomarkers of inflammation, coagulation, endothelial activation, and blood brain barrier (BBB) injury were associated with emergency department (ED) delirium duration.

Methods

We enrolled hospitalized patients who were 65 years or older from the ED. Plasma biomarkers of inflammation (interleukin-6 [IL-6], IL-8, soluble tumor necrosis factor receptor I [sTNFRI]), coagulation (Protein C), endothelial activation (plasminogen activating inhibitor-1 [PAI-1]), and BBB injury (S100B) at were measured using blood obtained at enrollment. The dependent variable was ED delirium duration which was determined by the Brief Confusion Assessment Method assessed in the ED and hospitalization. Proportional odds logistic regression analyses were performed adjusted for relevant confounders and allowing for interaction by baseline dementia status.

Results

A total of 156 patients were enrolled. IL-6 (POR = 1.59, 95%CI: 1.09–2.32) and PAI-1 (POR = 2.96, 95%CI: 1.48 to 6.85) were independently associated with more prominent ED delirium duration in subjects without dementia only. No significant associations between IL-8, Protein C, sTNRFI, and S100B and ED delirium duration were observed.

Conclusions

Plasma Biomarkers of systemic inflammation and endothelial activation are associated with ED delirium duration in older ED patients without dementia.

Is the Cerebellum Involved in the Nervous Control of the Immune System Function?

BACKGROUND

According to the views of psychoneuroendocrinoimmunology, many interactions exist between nervous, endocrine and immune system the purpose of which is to achieve adaptive measures restoring an internal equilibrium (homeostasis) following stress conditions. The center where these interactions converge is the hypothalamus. This is a center of the autonomic nervous system that controls the visceral systems, including the immune system, through both the nervous and neuroendocrine mechanisms. The nervous mechanisms are based on nervous circuits that bidirectionally connect hypothalamic neurons and neurons of the sympathetic and parasympathetic system; the neuroendocrine mechanisms are based on the release by neurosecretory hypothalamic neurons of hormones that target the endocrine cells and on the feedback effects of the hormones secreted by these endocrine cells on the same hypothalamic neurons. Moreover, the hypothalamus is an important subcortical center of the limbic system that controls through nervous and neuroendocrine mechanisms the areas of the cerebral cortex where the psychic functions controlling mood, emotions, anxiety and instinctive behaviors take place. Accordingly, various studies conducted in the last decades have indicated that hypothalamic diseases may be associated with immune and/or psychic disorders.

OBJECTIVE

Various researches have reported that the hypothalamus is controlled by the cerebellum through a feedback nervous circuit, namely the hypothalamocerebellar circuit, which bi-directionally connects regions of the hypothalamus, including the immunoregulatory ones, and related regions of the cerebellum. An objective of the present review was to analyze the anatomical bases of the nervous and neuroendocrine mechanisms for the control of the immune system and, in particular, of the interaction between hypothalamus and cerebellum to achieve the immunoregulatory function.

CONCLUSION

Since the hypothalamus represents the link through which the immune functions may influence the psychic functions and vice versa, the cerebellum, controlling several regions of the hypothalamus, could be considered as a primary player in the regulation of the multiple functional interactions postulated by psychoneuroendocrinoimmunology.

Vitamin D Deficiency and Long-Term Cognitive Impairment Among Older Adult Emergency Department Patients

INTRODUCTION

Approximately 16% of acutely ill older adults develop new, long-term cognitive impairment (LTCI), many of whom initially seek care in the emergency department (ED). Currently, no effective interventions exist to prevent LTCI after an acute illness. Identifying early and modifiable risk factors for LTCI is the first step toward effective therapy. We hypothesized that Vitamin D deficiency at ED presentation was associated with LTCI in older adults.

METHODS

This was an observational analysis of a prospective cohort study that enrolled ED patients ≥ 65 years old who were admitted to the hospital for an acute illness. All patients were enrolled within four hours of ED presentation. Serum Vitamin D was measured at enrollment and Vitamin D deficiency was defined as serum concentrations <20 mg/dL. We measured pre-illness and six-month cognition using the short form Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), which ranges from 1 to 5 (severe cognitive impairment). Multiple linear regression was performed to determine whether Vitamin D deficiency was associated with poorer six-month cognition adjusted for pre-illness IQCODE and other confounders. We incorporated a two-factor interaction into the regression model to determine whether the relationship between Vitamin D deficiency and six-month cognition was modified by pre-illness cognition.

RESULTS

We included a total of 134 older ED patients; the median (interquartile range [IQR]) age was 74 (69, 81) years old, 61 (46%) were female, and 14 (10%) were nonwhite race. The median (IQR) vitamin D level at enrollment was 25 (18, 33) milligrams per deciliter and 41 (31%) of enrolled patients met criteria for vitamin D deficiency. Seventy-seven patients survived and had a six-month IQCODE. In patients with intact pre-illness cognition (IQCODE of 3.13), Vitamin D deficiency was significantly associated with worsening six-month cognition (β-coefficient: 0.43, 95% CI, 0.07 to 0.78, p = 0.02) after adjusting for pre-illness IQCODE and other confounders. Among patients with pre-illness dementia (IQCODE of 4.31), no association with Vitamin D deficiency was observed (β-coefficient: -0.1;, 95% CI, [-0.50-0.27], p = 0.56).

CONCLUSION

Vitamin D deficiency was associated with poorer six-month cognition in acutely ill older adult ED patients who were cognitively intact at baseline. Future studies should determine whether early Vitamin D repletion in the ED improves cognitive outcomes in acutely ill older patients.

Profiling of how nociceptor neurons detect danger - new and old foes

The host evolves redundant mechanisms to preserve physiological processing and homeostasis. These functions range from sensing internal and external threats, creating a memory of the insult and generating reflexes, which aim to resolve inflammation. Impairment in such functioning leads to chronic inflammatory diseases. By interacting through a common language of ligands and receptors, the immune and sensory nervous systems work in concert to accomplish such protective functions. Whilst this bidirectional communication helps to protect from danger, it can contribute to disease pathophysiology. Thus, the somatosensory nervous system is anatomically positioned within primary and secondary lymphoid tissues and mucosa to modulate immunity directly. Upstream of this interplay, neurons detect danger, which prompts the release of neuropeptides initiating (i) defensive reflexes (ranging from withdrawal response to coughing) and (ii) chemotaxis, adhesion and local infiltration of immune cells. The resulting outcome of such neuro-immune interplay is still ill-defined, but consensual findings start to emerge and support neuropeptides not only as blockers of T_H 1-mediated immunity but also as drivers of T_H 2 immune responses. However, the modalities detected by nociceptors revealed broader than mechanical pressure and temperature sensing and include signals as various as cytokines and pathogens to immunoglobulins and even microRNAs. Along these lines, we aggregated various dorsal root ganglion sensory neuron expression profiling datasets supporting such wide-ranging sensing capabilities to help identifying new danger detection modalities of these cells. Thus, revealing unexpected aspects of nociceptor neuron biology might prompt the identification of novel drivers of immunity, means to resolve inflammation and strategies to safeguard homeostasis.

Neurons and Microglia; A Sickly-Sweet Duo in Diabetic Pain Neuropathy

Diabetes is a common condition characterized by persistent hyperglycemia. High blood sugar primarily affects cells that have a limited capacity to regulate their glucose intake. These cells include capillary endothelial cells in the retina, mesangial cells in the renal glomerulus, Schwann cells, and neurons of the peripheral and central nervous systems. As a result, hyperglycemia leads to largely intractable complications such as retinopathy, nephropathy, hypertension, and neuropathy. Diabetic pain neuropathy is a complex and multifactorial disease that has been associated with poor glycemic control, longer diabetes duration, hypertension, advanced age, smoking status, hypoinsulinemia, and dyslipidemia. While many of the driving factors involved in diabetic pain are still being investigated, they can be broadly classified as either neuron -intrinsic or -extrinsic. In neurons, hyperglycemia impairs the polyol pathway, leading to an overproduction of reactive oxygen species and reactive nitrogen species, an enhanced formation of advanced glycation end products, and a disruption in Na⁺/K⁺ ATPase pump function. In terms of the extrinsic pathway, hyperglycemia leads to the generation of both overactive microglia and microangiopathy. The former incites a feed-forward inflammatory loop that hypersensitizes nociceptor neurons, as observed at the onset of diabetic pain neuropathy. The latter reduces neurons' access to oxygen, glucose and nutrients, prompting reductions in nociceptor terminal expression and losses in sensation, as observed in the later stages of diabetic pain neuropathy. Overall, microglia can be seen as potent and long-lasting amplifiers of nociceptor neuron activity, and may therefore constitute a potential therapeutic target in the treatment of diabetic pain neuropathy.

Sympathetic Nerve Hyperactivity in the Spleen: Causal for Nonpathogenic-Driven Chronic Immune-Mediated Inflammatory Diseases (IMIDs)?

Immune-Mediated Inflammatory Diseases (IMIDs) is a descriptive term coined for an eclectic group of diseases or conditions that share common inflammatory pathways, and for which there is no definitive etiology. IMIDs affect the elderly most severely, with many older individuals having two or more IMIDs. These diseases include, but are not limited to, type-1 diabetes, obesity, hypertension, chronic pulmonary disease, coronary heart disease, inflammatory bowel disease, and autoimmunity, such as rheumatoid arthritis (RA), Sjőgren's syndrome, systemic lupus erythematosus, psoriasis, psoriatic arthritis, and multiple sclerosis. These diseases are ostensibly unrelated mechanistically, but increase in frequency with age and share chronic systemic inflammation, implicating major roles for the spleen. Chronic systemic and regional inflammation underlies the disease manifestations of IMIDs. Regional inflammation and immune dysfunction promotes targeted end organ tissue damage, whereas systemic inflammation increases morbidity and mortality by affecting multiple organ systems. Chronic inflammation and skewed dysregulated cell-mediated immune responses drive many of these age-related medical disorders. IMIDs are commonly autoimmune-mediated or suspected to be autoimmune diseases. Another shared feature is dysregulation of the autonomic nervous system and hypothalamic pituitary adrenal (HPA) axis. Here, we focus on dysautonomia. In many IMIDs, dysautonomia manifests as an imbalance in activity/reactivity of the sympathetic and parasympathetic divisions of the autonomic nervous system (ANS). These major autonomic pathways are essential for allostasis of the immune system, and regulating inflammatory processes and innate and adaptive immunity. Pathology in ANS is a hallmark and causal feature of all IMIDs. Chronic systemic inflammation comorbid with stress pathway dysregulation implicate neural-immune cross-talk in the etiology and pathophysiology of IMIDs. Using a rodent model of inflammatory arthritis as an IMID model, we report disease-specific maladaptive changes in β₂-adrenergic receptor (AR) signaling from protein kinase A (PKA) to mitogen activated protein kinase (MAPK) pathways in the spleen. Beta₂-AR signal "shutdown" in the spleen and switching from PKA to G-coupled protein receptor kinase (GRK) pathways in lymph node cells drives inflammation and disease advancement. Based on these findings and the existing literature in other IMIDs, we present and discuss relevant literature that support the hypothesis that unresolvable immune stimulation from chronic inflammation leads to a maladaptive disease-inducing and perpetuating sympathetic response in an attempt to maintain allostasis. Since the role of sympathetic dysfunction in IMIDs is best studied in RA and rodent models of RA, this IMID is the primary one used to evaluate data relevant to our hypothesis. Here, we review the relevant literature and discuss sympathetic dysfunction as a significant contributor to the pathophysiology of IMIDs, and then discuss a novel target for treatment. Based on our findings in inflammatory arthritis and our understanding of common inflammatory process that are used by the immune system across all IMIDs, novel strategies to restore SNS homeostasis are expected to provide safe, cost-effective approaches to treat IMIDs, lower comorbidities, and increase longevity.

Neuropeptide regulation of adaptive immunity in the tibia fracture model of complex regional pain syndrome

Background

Both dysfunctional neuropeptide signaling and immune system activation are characteristic of complex regional pain syndrome (CRPS). Unknown is whether substance P (SP) or calcitonin gene-related peptide (CGRP) support autoantibody production and, consequently, nociceptive sensitization.

Methods

These experiments involved the use of a well-characterized tibia fracture model of CRPS. Mice deficient in SP expression (Tac1^−/−) and CGRP signaling (RAMP1^−/−) were used to probe the neuropeptide dependence of post-fracture sensitization and antibody production. The deposition of IgM in the spinal cord, sciatic nerves, and skin was followed using Western blotting, as was expression of the CRPS-related autoantigen cytokeratin 16 (Krt16). Passive serum transfer to B-cell-deficient muMT mice was used to assess the production of functional autoantibodies in CRPS model mice. The use of immunohistochemistry allowed us to assess neuropeptide-containing fiber distribution and Langerhans cell abundance in mouse and human CRPS patient skin, while Langerhans cell-deficient mice were used to assess the functional contributions of these cells.

Results

Functional SP and CGRP signaling were required both for the full development of nociceptive sensitization after fracture and the deposition of IgM in skin and neural tissues. Furthermore, the passive transfer of serum from wildtype but not neuropeptide-deficient mice to fractured muMT mice caused enhanced allodynia and postural unweighting. Langerhans cells were increased in number in the skin of fracture mice and CRPS patients, and those increases in mice were reduced in neuropeptide signaling-deficient animals. Unexpectedly, Langerhans cell-deficient mice showed normal nociceptive sensitization after fracture. However, the increased expression of Krt16 after tibia fracture was not seen in neuropeptide-deficient mice.

Conclusions

Collectively, these data support the hypothesis that neuropeptide signaling in the fracture limb of mice is required for autoantigenic IgM production and nociceptive sensitization. The mechanism may be related to neuropeptide-supported autoantigen expression.

Weaning stress and gastrointestinal barrier development: Implications for lifelong gut health in pigs

The gastrointestinal (GI) barrier serves a critical role in survival and overall health of animals and humans. Several layers of barrier defense mechanisms are provided by the epithelial, immune and enteric nervous systems. Together they act in concert to control normal gut functions (e.g., digestion, absorption, secretion, immunity, etc.) whereas at the same time provide a barrier from the hostile conditions in the luminal environment. Breakdown of these critical GI functions is a central pathophysiological mechanism in the most serious GI disorders in pigs. This review will focus on the development and functional properties of the GI barrier in pigs and how common early life production stressors, such as weaning, can alter immediate and long-term barrier function and disease susceptibility. Specific stress-related pathophysiological mechanisms responsible for driving GI barrier dysfunction induced by weaning and the implications to animal health and performance will be discussed.

Modulatory in vitro effect of stress hormones on the cytokine response of rainbow trout and gilthead sea bream head kidney stimulated with Vibrio anguillarum bacterin

In fish, the stress response and their consequences in the immune system have been widely described. Recently, a differential cytokine regulation between rainbow trout (Oncorhynchus mykiss) and gilthead sea bream (Sparus aurata) was reported after treatment with stress hormones together with their receptor antagonists. Nevertheless, there is no evidence of whether antagonists for stress hormone receptors may influence the interaction between hormones and cytokines after bacterial administration. Thus, the aim of our study was to evaluate the cytokine expression in the presence of stress hormones (cortisol, ACTH, adrenaline), hormone receptor antagonists and inactivated Vibrio anguillarum bacterin in rainbow trout and gilthead sea bream head kidney primary cell culture (HKPCC). Mifepristone, spironolactone, propranolol and phentolamine were used to block GR, MR, MC2R, and β-/α-adrenoreceptors. Our results showed an expected increase of the pro-inflammatory and anti-inflammatory response after inactivated V. anguillarum bacterin treatment in both species. Cortisol, ACTH and adrenaline did not modulate the expression of immune-related genes in rainbow trout, while in sea bream cortisol was able to reduce the stimulated gene expression of all cytokines. This effect was only restored to basal expression level in IL-1β and TNF-α by mifepristone. ACTH reduced both pro-inflammatory and anti-inflammatory cytokine expression, excluding IL-1β, only in sea bream. Adrenaline enhanced the expression of IL-1β and TGF-β1 stimulated by inactivated V. anguillarum in sea bream, and the effect was diminished by propranolol. In sum, our results confirm that the immunoendocrine differences reported at gene expression profile between two teleost species are also observed after exposure to inactivated V. anguillarum bacterin, suggesting that stress hormones would differentially modulate the immune response against pathogens in teleost species.

[Non-withdrawal-related delirium : Evidence on prevention and therapy]

Delirium is a severe and common yet under-diagnosed disorder in the clinical routine. Multiple factors may contribute to the development of delirium, which is associated with increased mortality and high healthcare costs. Treatment of delirium is often provided with delay and limited to pharmacological interventions. This article summarizes the key symptoms for delirium as well as risk factors and highlights the pharmacological and non-pharmacological options for treatment and prevention.

Modulation of Dental Inflammation by the Sympathetic Nervous System

Recent findings have indicated that immune responses are subjected to modulation by the sympathetic nervous system (SNS). Moreover, the findings show that the SNS inhibits the production of pro-inflammatory cytokines, while stimulating the production of anti-inflammatory cytokines. The present review is an attempt to summarize the current results on how the SNS affects inflammation in dental tissues. In dental tissues, it has been found that the SNS is significant for recruitment of inflammatory cells such as CD 43+ granulocytes. Sympathetic nerves appear to have an inhibitory effect on osteoclasts, odontoclasts, and on IL-1α production. The SNS stimulates reparative dentin production, since reparative dentin formation was reduced after sympathectomy. Sprouting of sympathetic nerve fibers occurs in chronically inflamed dental pulp, and neural imbalance caused by unilateral sympathectomy recruits immunoglobulin-producing cells to the dental pulp. In conclusion, this article presents evidence in support of interactions between the sympathetic nervous system and dental inflammation.

Fish oil enhances intestinal barrier function and inhibits corticotropin-releasing hormone/corticotropin-releasing hormone receptor 1 signalling pathway in weaned pigs after lipopolysaccharide challenge

Stress induces injury in intestinal barrier function in piglets. Long-chain n-3 PUFA have been shown to exhibit potential immunomodulatory and barrier protective effects in animal models and clinical trials. In addition, corticotropin-releasing hormone (CRH)/CRH receptor (CRHR) signalling pathways play an important role in stress-induced alterations of intestinal barrier function. We hypothesised that fish oil could affect intestinal barrier function and CRH/CRHR signalling pathways. In total, thirty-two weaned pigs were allocated to one of four treatments. The experiment consisted of a 2×2 factorial design, and the main factors included immunological challenge (saline or lipopolysaccharide (LPS)) and diet (5 % maize oil or 5 % fish oil). On d 19 of the trial, piglets were treated with saline or LPS. At 4 h after injection, all pigs were killed, and the mesenteric lymph nodes (MLN), liver, spleen and intestinal samples were collected. Fish oil decreased bacterial translocation incidence and the number of translocated micro-organisms in the MLN. Fish oil increased intestinal claudin-1 protein relative concentration and villus height, as well as improved the intestinal morphology. In addition, fish oil supplementation increased intestinal intraepithelial lymphocyte number and prevented elevations in intestinal mast cell and neutrophil numbers induced by LPS challenge. Moreover, fish oil tended to decrease the mRNA expression of intestinal CRHR1, CRH and glucocorticoid receptors. These results suggest that fish oil supplementation improves intestinal barrier function and inhibits CRH/CRHR1 signalling pathway and mast cell tissue density.

The Regulation of Immunological Processes by Peripheral Neurons in Homeostasis and Disease

The nervous system and the immune system are the principal sensory interfaces between the internal and external environment. They are responsible for recognizing, integrating, and responding to varied stimuli, and have the capacity to form memories of these encounters leading to learned or 'adaptive' future responses. We review current understanding of the cross-regulation between these systems. The autonomic and somatosensory nervous systems regulate both the development and deployment of immune cells, with broad functions that impact on hematopoiesis as well as on priming, migration, and cytokine production. In turn, specific immune cell subsets contribute to homeostatic neural circuits such as those controlling metabolism, hypertension, and the inflammatory reflex. We examine the contribution of the somatosensory system to autoimmune, autoinflammatory, allergic, and infectious processes in barrier tissues and, in this context, discuss opportunities for therapeutic manipulation of neuro-immune interactions.

Training-related risk of common illnesses in elite swimmers over a 4-yr period

PURPOSE

The objective of this study is to investigate the relation between sport training and the risk of common illnesses: upper respiratory tract and pulmonary infections (URTPI), muscular affections (MA), and all-type pathologies in highly trained swimmers.

METHODS

Twenty-eight French professional swimmers were monitored weekly for 4 yr. Training variables included 1) in-water and dryland intensity levels: low-load, high-load, resistance, maximal strength, and general conditioning training (expressed as the percentage of the maximal load performed by each subject, at each intensity level over the study period); and 2) training periods: moderate, intensive, taper, competition, and postcompetition. Illnesses were diagnosed by a sports physician using a standardized questionnaire. Mixed-effects logistic regression analyses were used to model odds ratios for the association between common illnesses and training variables, adjusted for sport season, semiseason (summer or winter), age, competition level, sex, and history of recent events, whereas controlling for heterogeneity among swimmers.

RESULTS

The risk of common illnesses was significantly higher in winter months, for national swimmers (for URTPI), and in cases of history of recent event (notably for MA). The odds of URTPI increased 1.08 (95% CI, 1.01-1.16) and 1.10 (95% CI, 1.01-1.19) times for every 10% increase in resistance and high-load trainings, respectively. The odds of MA increased by 1.49 (95% CI, 1.14-1.96) and 1.63 (95% CI, 1.20-2.21) for each 10% increase in high load and general conditioning training, respectively. The odds of illnesses were 50%-70% significantly higher during intensive training periods.

CONCLUSION

Particular attention must be paid to illness prevention strategies during periods of intensive training, particularly in the winter months or in case of the recent medical episode.

Functional changes in neutrophils and psychoneuroendocrine responses during 105 days of confinement

The innate immune system as one key element of immunity and a prerequisite for an adequate host defense is of emerging interest in space research to ensure crew health and thus mission success. In ground-based studies, spaceflight-associated specifics such as confinement caused altered immune functions paralleled by changes in stress hormone levels. In this study, six men were confined for 105 days to a space module of ∼500 m3mimicking conditions of a long-term space mission. Psychic stress was surveyed by different questionnaires. Blood, saliva, and urine samples were taken before, during, and after confinement to determine quantitative and qualitative immune responses by analyzing enumerative assays and quantifying microbicide and phagocytic functions. Additionally, expression and shedding of L-selectin (CD62L) on granulocytes and different plasma cytokine levels were measured. Cortisol and catecholamine levels were analyzed in saliva and urine. Psychic stress or an activation of the psychoneuroendocrine system could not be testified. White blood cell counts were not significantly altered, but innate immune functions showed increased cytotoxic and reduced microbicide capabilities. Furthermore, a significantly enhanced shedding of CD62L might be a hint at increased migratory capabilities. However, this was observed in the absence of any acute inflammatory state, and no rise in plasma cytokine levels was detected. In summary, confinement for 105 days caused changes in innate immune functions. Whether these changes result from an alert immune state in preparation for further immune challenges or from a normal adaptive process during confinement remains to be clarified in future research.

Immune neuroendocrine phenotypes in Coturnix coturnix: do avian species show LEWIS/FISCHER-like profiles?

Immunoneuroendocrinology studies have identified conserved communicational paths in birds and mammals, e.g. the Hypothalamus-Pituitary-Adrenal axis with anti-inflammatory activity mediated by glucocorticoids. Immune neuroendocrine phenotypes (INPs) have been proposed for mammals implying the categorization of a population in subgroups underlying divergent immune-neuroendocrine interactions. These phenotypes were studied in the context of the LEWIS/FISCHER paradigm (rats expressing high or low pro-inflammatory profiles, respectively). Although avian species have some common immunological mechanisms with mammals, they have also evolved some distinct strategies and, until now, it has not been studied whether birds may also share with mammals similar INPs. Based on corticosterone levels we determined the existence of two divergent groups in Coturnix coturnix that also differed in other immune-neuroendocrine responses. Quail with lowest corticosterone showed higher lymphoproliferative and antibody responses, interferon-γ and interleukin-1β mRNA expression levels and lower frequencies of leukocyte subpopulations distribution and interleukin-13 levels, than their higher corticosterone counterparts. Results suggest the existence of INPs in birds, comparable to mammalian LEWIS/FISCHER profiles, where basal corticosterone also underlies responses of comparable variables associated to the phenotypes. Concluding, INP may not be a mammalian distinct feature, leading to discuss whether these profiles represent a parallel phenomenon evolved in birds and mammals, or a common feature inherited from a reptilian ancestor millions of years ago.

The enteric nervous system neuropeptide, bombesin, reverses innate immune impairments during parenteral nutrition

BACKGROUND

Lack of enteral stimulation during parenteral nutrition (PN) impairs mucosal immunity. Bombesin (BBS), a gastrin-releasing peptide analogue, reverses PN-induced defects in acquired immunity. Paneth cells produce antimicrobial peptides (AMPs) of innate immunity for release after cholinergic stimulation.

OBJECTIVE

Determine if BBS restores AMPs and bactericidal function during PN.

METHODS

Intravenously cannulated male ICR mice were randomized to Chow, PN, or PN+BBS (15 μg 3 times daily, n = 7 per group) for 5 days. Ileum was analyzed for AMPs (Protein: sPLA2 by fluorescence, lysozyme and RegIII-γ by western andcryptdin-4 by ELISA; mRNA: all by RT-PCR). Cholinergic stimulated (100 μM bethanechol) ileal specimens assessed Pseudomonas bactericidal activity. Ileum (Chow: n = 7; PN: n = 9; PN+BBS: n = 8) was assessed for Escherichia coli invasion in ex-vivo culture.

RESULTS

PN significantly decreased most AMPs versus Chow while BBS maintained Chow levels (sPLA2: Chow: 107 + 14*, PN: 44.6 + 7.2, PN+BBS: 78.7 + 13.4* Fl/min/μL/total protein; Lysozyme: Chow: 63.9 + 11.9*, PN: 26.8 + 6.2; PN+BBS: 64.9 + 13.8* lysozyme/total protein; RegIII-γ: Chow: 51.5 + 10.0*, PN: 20.4 + 4.3, PN+BBS: 31.0 + 8.4 RegIII-γ/total protein; Cryptdin-4: Chow: 18.4 + 1.5*, PN: 12.7 + 1.6, PN+BBS: 26.1 + 2.4*† pg/mg [all *P < 0.05 vs PN and †P < 0.05 vs Chow]). Functionally, BBS prevented PN loss of bactericidal activity after cholinergic stimulation (Chow: 25.3 + 3.6*, PN: 13.0 + 3.2; PN+BBS: 27.0 + 4.7* percent bacterial killing, *P < 0.05 vs PN). BBS reduced bacterial invasion in unstimulated tissue barely missing significance (P = 0.06).

CONCLUSIONS

The enteric nervous system (ENS) controls AMP levels in Paneth cells during PN but mucosal protection by innate immunity requires both ENS and parasympathetic stimulation.

Chemical sympathectomy increases neutrophil-to-lymphocyte ratio in tumor-bearing rats but does not influence cancer progression

The sympathetic nervous system regulates many immune functions and modulates the anti-tumor immune defense response, too. Therefore, we studied the effect of 6-hydroxydopamine induced sympathectomy on selected hematological parameters and inflammatory markers in rats with Yoshida AH130 ascites hepatoma. We found that chemically sympathectomized tumor-bearing rats had significantly increased neutrophil-to-lymphocyte ratio, leukocyte-to-lymphocyte ratio, and plasma levels of tumor necrosis factor alpha. Although our findings showed that sympathetic denervation in tumor-bearing rats led to increased neutrophil-to-lymphocyte ratio, that is an indicator of the disease progression, we found no significant changes in tumor growth and survival of sympathectomized tumor-bearing rats.

The immunology of delirium

Delirium is an acute neuropsychiatric syndrome characterized by acute-onset global cognitive deficits, perceptual and behavioural disturbances affecting mainly elderly subjects with underlying medical or surgical conditions. The pathophysiology of delirium is complex and inflammation is a relevant precipitant factor of this syndrome, although it remains unclear how acute systemic inflammation induces the clinical picture of delirium. The central nervous system is able to detect peripheral infection or tissue destruction through circulating immune mediators and neural ascending signs. Activated microglia is responsible for an acute neuroinflammatory reaction underlying the symptoms of sickness. In healthy conditions descending pathways from the paraventricular nucleus, locus coeruleus and dorsal motor nucleus organize a centralized response to influence the immune response at the periphery and restore homeostasis. In the context of ageing and chronic neurodegeneration, adaptive changes to acute insults are characterized by exaggerated production of pro-inflammatory cytokines by primed microglia coupled with dysfunction of brain-to-immune pathways. In animal models, these changes underlie a more severe manifestation of sickness behaviour with working memory deficits suggesting that inattention, a core feature of delirium, can be a clinical correlate of an increased neuroinflammatory reaction. In patients with delirium, higher levels of pro-inflammatory cytokines and cortisol were identified in plasma and cerebrospinal fluid. However, to date it has not been clarified how peripheral inflammatory or endocrine biomarkers can reflect the likelihood or severity of delirium symptoms. In the future, a better understanding of the interaction between the brain and peripheral organs and the exact mechanism by which systemic inflammation can lead to delirium, will allow the development of new therapeutic agents.

The microbiota-gut-brain axis: neurobehavioral correlates, health and sociality

Recent data suggest that the human body is not such a neatly self-sufficient island after all. It is more like a super-complex ecosystem containing trillions of bacteria and other microorganisms that inhabit all our surfaces; skin, mouth, sexual organs, and specially intestines. It has recently become evident that such microbiota, specifically within the gut, can greatly influence many physiological parameters, including cognitive functions, such as learning, memory and decision making processes. Human microbiota is a diverse and dynamic ecosystem, which has evolved in a mutualistic relationship with its host. Ontogenetically, it is vertically inoculated from the mother during birth, established during the first year of life and during lifespan, horizontally transferred among relatives, mates or close community members. This micro-ecosystem serves the host by protecting it against pathogens, metabolizing complex lipids and polysaccharides that otherwise would be inaccessible nutrients, neutralizing drugs and carcinogens, modulating intestinal motility, and making visceral perception possible. It is now evident that the bidirectional signaling between the gastrointestinal tract and the brain, mainly through the vagus nerve, the so called “microbiota–gut–vagus–brain axis,” is vital for maintaining homeostasis and it may be also involved in the etiology of several metabolic and mental dysfunctions/disorders. Here we review evidence on the ability of the gut microbiota to communicate with the brain and thus modulate behavior, and also elaborate on the ethological and cultural strategies of human and non-human primates to select, transfer and eliminate microorganisms for selecting the commensal profile.

The prevalence and clinical characteristics of primary headache in irritable bowel syndrome: a subgroup of the functional somatic syndromes

CONTEXT

The irritable bowel syndrome and primary headache are two chronic diseases characterized by symptoms of recurring pain and affect approximately 10%-20% of the general population.

OBJECTIVES

To study the prevalence of primary headache in volunteers with irritable bowel syndrome in a Brazilian urban community.

METHODS

It was evaluated the prevalence of primary headache associated with irritable bowel syndrome in adult volunteers 330 no patients.The protocol included the Rome III criteria, international classification of Headaches, later divided into four groups: I- Irritable bowel syndrome (n = 52), II- Primary headache (n = 45), III-Irritable bowel syndrome (n = 26) and headache, and IV- Controls (207).

RESULTS

We not found significant difference in the average age of the four groups and the diagnosis of irritable bowel syndrome, primary headache and their association was more frequent in females. The frequent use of analgesics was greater in groups II and III.

CONCLUSION

Our results suggest that irritable bowel syndrome and primary headache are also common in third world countries. The frequency in use of analgesics in association between the two entities was relevant. The identification of irritable bowel syndrome patients with different clinical sub-types could improve the therapeutics options and the prevention strategies.

Parasympathetic stimulation via the vagus nerve prevents systemic organ dysfunction by abrogating gut injury and lymph toxicity in trauma and hemorrhagic shock

We tested if vagus nerve stimulation (VNS) would prevent gut injury, mesenteric lymph toxicity, and systemic multiple organ dysfunction syndrome following trauma-hemorrhagic shock (T/HS). Four groups of experiments were performed. The first tested whether VNS (5 V for 10 min) would protect against T/HS-induced increases in gut and lung permeability as well as neutrophil priming. In the second experiment, mesenteric lymph was collected from rats subjected to T/HS or trauma-sham shock with or without VNS and then injected into naive mice to assess its biologic activity. Lung permeability, neutrophil priming, and red blood cell deformability were measured. Next, the role of the spleen in VNS-mediated protection was tested by measuring gut and lung injury in splenectomized rats subjected to sham or actual VNS. Lastly, the ability of nicotine to replicate the gut-protective effect of VNS was tested. Vagus nerve stimulation protected against T/HS-induced gut injury, lung injury, and neutrophil priming (P < 0.05). Not only did VNS limit organ injury after T/HS, but in contrast to the mesenteric lymph collected from the sham-VNS T/HS rats, the mesenteric lymph from the VNS T/HS rats did not cause lung injury, neutrophil priming, or loss of red blood cell deformability (P < 0.05) when injected into naive mice. Removal of the spleen did not prevent the protective effects of VNS on gut or lung injury after T/HS. Similar to VNS, the administration of nicotine also protected the gut from injury after T/HS. Vagus nerve stimulation prevents T/HS-induced gut injury, lung injury, neutrophil priming, and the production of biologically active mesenteric lymph. This protective effect of VNS was not dependent on the spleen but appeared to involve a cholinergic nicotinic receptor, because its beneficial effects could be replicated with nicotine.

Impact of Heat Stress on Poultry Production

Simple Summary

Due to the common occurrence of environmental stressors worldwide, many studies have investigated the detrimental effects of heat stress on poultry production. It has been shown that heat stress negatively affects the welfare and productivity of broilers and laying hens. However, further research is still needed to improve the knowledge of basic mechanisms associated to the negative effects of heat stress in poultry, as well as to develop effective interventions.

Abstract

Understanding and controlling environmental conditions is crucial to successful poultry production and welfare. Heat stress is one of the most important environmental stressors challenging poultry production worldwide. The detrimental effects of heat stress on broilers and laying hens range from reduced growth and egg production to decreased poultry and egg quality and safety. Moreover, the negative impact of heat stress on poultry welfare has recently attracted increasing public awareness and concern. Much information has been published on the effects of heat stress on productivity and immune response in poultry. However, our knowledge of basic mechanisms associated to the reported effects, as well as related to poultry behavior and welfare under heat stress conditions is in fact scarce. Intervention strategies to deal with heat stress conditions have been the focus of many published studies. Nevertheless, effectiveness of most of the interventions has been variable or inconsistent. This review focuses on the scientific evidence available on the importance and impact of heat stress in poultry production, with emphasis on broilers and laying hens.

Chlorella vulgaris treatment ameliorates the suppressive effects of single and repeated stressors on hematopoiesis

The reports regarding the mutual influence between the central nervous system and the immune system constitute a vast and somewhat controversial body of literature. Stress is known to disturb homeostasis, impairing immunological functions. In this study, we investigated the hematopoietic response of Chlorella vulgaris (CV)-treated mice exposed to single (SST) and repeated stress (RST). We observed a reduction in the numbers of hematopoietic progenitors (HP) in the bone marrow and long-term bone marrow cultures (LTBMC) using flow cytometry and a coinciding decrease in the number of granulocyte-macrophage colonies (CFU-GM) after treatment with both stressors, but SST caused a more profound suppression. We observed a proportional increase in the colony-stimulating activity (CSA) of the serum of animals subjected to SST or RST. In the bone marrow, SST and RST induced a decrease in both mature myeloid and lymphoid populations but did not affect pluripotent hematopoietic progenitors (Lin(-)Sca-1(+)c-kit(+), LSK), and again, a more profound suppression was observed after SST. We further quantified the levels of interleukin-1α (IL-1α) and interleukin-6 (IL-6) and the number of myeloid cells in LTBMC. Both SST and RST reduced the levels of these cytokines to similar degrees. The myeloid population was also reduced in LTBMC, and SST induced a more intense suppression. Importantly, CV treatment prevented the changes produced by SST and RST in all of the parameters evaluated. Together, our results suggest that CV treatment is an effective tool for the prophylaxis of myelosuppression caused by single or repeated stressors.

Neurokinin-1 receptor agonists bias therapeutic dendritic cells to induce type 1 immunity by licensing host dendritic cells to produce IL-12

Substance-P and hemokinin-1 are proinflammatory neuropeptides with potential to promote type 1 immunity through agonistic binding to neurokinin-1 receptor (NK1R). Dendritic cells (DCs) are professional antigen-presenting cells that initiate and regulate the outcome of innate and adaptive immune responses. Immunostimulatory DCs are highly desired for the development of positive immunization techniques. DCs express functional NK1R; however, regardless of their potential DC-stimulatory function, the ability of NK1R agonists to promote immunostimulatory DCs remains unexplored. Here, we demonstrate that NK1R signaling activates therapeutic DCs capable of biasing type 1 immunity by inhibition of interleukin-10 (IL-10) synthesis and secretion, without affecting their low levels of IL-12 production. The potent type 1 effector immune response observed following cutaneous administration of NK1R-signaled DCs required their homing in skin-draining lymph nodes (sDLNs) where they induced inflammation and licensed endogenous-conventional sDLN-resident and -recruited inflammatory DCs to secrete IL-12. Our data demonstrate that NK1R signaling promotes immunostimulatory DCs, and provide relevant insight into the mechanisms used by neuromediators to regulate innate and adaptive immune responses.

S100+ cells: a new neuro-immune cross-talkers in lymph organs

Up to now, the ‘hardwired’ neural pathway of the neuro-immune regulation is not fully understood. Here we reported a new neural pathway which links sympathetic nerves with immune cells of the lymphoid tissues. Our results demonstrated that nerve fibers derived from superior cervical ganglion directly targeted only S100⁺ cells in the cervical lymph nodes. Moreover, we found co-expression of neurotransmitters such as norepinephrine, vasoactive intestinal polypeptide and neuropeptide Y in the postganglionic sympathetic nerve endings that innervate S100⁺ cells. Our findings suggested that S100⁺ cells serve as a neuro-immune cross-talker in lymph organs that may play a significant role in transmitting signals of nervous cells to targeted immune cells. The new findings provide better understanding of the cross-talk mechanism between the nervous system and the immune system.

Insights into the clinical and functional significance of cardiac autonomic dysfunction in Chagas disease

INTRODUCTION

Exclusive or associated lesions in various structures of the autonomic nervous system occur in the chronic forms of Chagas disease. In the indeterminate form, the lesions are absent or mild, whereas in the exclusive or combined heart and digestive disease forms, they are often more pronounced. Depending on their severity these lesions can result mainly in cardiac parasympathetic dysfunction but also in sympathetic dysfunction of variable degrees. Despite the key autonomic effect on cardiovascular functioning, the pathophysiological and clinical significance of the cardiac autonomic dysfunction in Chagas disease remains unknown.

METHODS

Review of data on the cardiac autonomic dysfunction in Chagas disease and their potential consequences, and considerations supporting the possible relationship between this disturbance and general or cardiovascular clinical and functional adverse outcomes.

RESULTS

We hypothesise that possible consequences that cardiac dysautonomia might variably occasion or predispose in Chagas disease include: transient or sustained arrhythmias, sudden cardiac death, adverse overall and cardiovascular prognosis with enhanced morbidity and mortality, an inability of the cardiovascular system to adjust to functional demands and/or respond to internal or external stimuli by adjusting heart rate and other hemodynamic variables, and immunomodulatory and cognitive disturbances.

CONCLUSIONS

Impaired cardiac autonomic modulation in Chagas disease might not be a mere epiphenomenon without significance. Indirect evidences point for a likely important role of this alteration as a primary predisposing or triggering cause or mediator favouring the development of subtle or evident secondary cardiovascular functional disturbances and clinical consequences, and influencing adverse outcomes.

Cholinergic signalling in gut immunity

The gut immune system shares many signalling molecules and receptors with the autonomic nervous system. A good example is the vagal neurotransmitter acetylcholine (ACh), for which many immune cell types express cholinergic receptors (AChR). In the last decade the vagal nerve has emerged as an integral part of an immune regulation network via its release of ACh; a system coined "the cholinergic anti-inflammatory reflex". The perspective of cholinergic immune regulation in the gut mucosa has been widened by the recent discovery of populations of ACh producing immune cells in the spleen and other organs. As such, ACh, classically referred to as neurotransmitter, may serve a much broader function as bi-directional signalling molecule between neurons and non-neuronal cell types of the immune system.

You may need the vagus nerve to understand pathophysiology and to treat diseases

Can different pathophysiological mechanisms and risk factors leading to various diseases be linked with altered transmission of signals by one common pathway? The present article provides evidence for the hypothesis that adequate vagal nerve activity reduces the risk of major diseases, via common basic mechanisms and interim risk factors. These diseases include cardiovascular disease, cancer, Alzheimer's disease and the metabolic syndrome. Three basic mechanisms contribute to such illnesses: local oxidative stress and DNA damage, inflammatory reactions and excessive sympathetic responses, all of which are inhibited by vagal nerve activity. Efferent vagal activity that can be non-invasively measured by HRV (heart rate variability), derived from an ECG, is inversely related to all three basic mechanisms, to various risk factors (e.g. diabetes and dyslipidaemia) and, more broadly, to the diseases as well. Finally, vagal activity is proposed to moderate the effects of risk factors on developing such illnesses. By proposing an integrative neurobiological model of major diseases, identifying people at risk for, and treating patients with, such diseases may be done more efficiently. People with low HRV may be identified and subsequently treated by vagus nerve activation to possibly prevent or treat such illnesses. This proposed disease paradigm may have important preventative and therapeutic implications, whose clinical effects need to be investigated.

Leukocyte β2-adrenergic receptor expression in response to resistance exercise

PURPOSE

Epinephrine and norepinephrine mediate interactions between the neuroendocrine and the immune systems to alter immune cell activity. Although both systems respond to exercise stress, less is known about how they interact in response to such stress. The purpose of this investigation was to examine β2-adrenergic receptor (β2-ADR) expression on circulating leukocytes to an acute bout of resistance exercise in men and women.

METHODS

Resistance-trained men (n = 8; mean ± SD age = 24.63 ± 5.07 yr, body mass index = 26.09 ± 2.21 kg·m(-2)) and women (n = 7; age = 22.13 ± 3.09 yr, body mass index = 22.63 ± 2.03 kg·m(-2)) performed an acute resistance exercise protocol (six sets of five-repetition maximum heavy squats) and a control test (i.e., identical conditions with no exercise) in a balanced, randomized order. Using a within-subject design, β2-ADR expressions on circulating leukocytes were evaluated with flow cytometry, and plasma epinephrine and norepinephrine were evaluated with high-performance liquid chromatography.

RESULTS

Plasma epinephrine and norepinephrine increased during the exercise bout and returned to baseline during recovery. β2-ADR expression on monocytes was elevated in anticipation of the exercise protocol. β2-ADR expression on monocytes and granulocytes decreased during the exercise. β2-ADR expression on lymphocytes was elevated during the recovery time points.

CONCLUSIONS

In conclusion, β2-ADR expression on leukocyte subpopulations changes in response to acute heavy resistance exercise protocol. The present findings provide insights into the potential temporal interactions between the neuroendocrine and the immune systems in response to the physiological stress of acute heavy resistance exercise in men and women.

Cholinergic regulatory lymphocytes re-establish neuromodulation of innate immune responses in sepsis

Many anti-inflammatory strategies that are successful in treating sepsis in healthy animals fail in clinical trials, in part because sepsis normally involves immunocompromised patients, and massive lymphocyte apoptosis prevents immunomodulation. In this article, we report a new set of regulatory lymphocytes that are able to re-establish the cholinergic anti-inflammatory modulation and to provide therapeutic advantages in sepsis. The vagus nerve controls inflammation in healthy, but not in septic, mice. Likewise, vagus nerve and cholinergic agonists fail to control inflammation in splenectomized and nude animals. Unlike typical suppressor CD25(+) cells, CD4(+)CD25(-) lymphocytes re-establish the anti-inflammatory potential of the vagus nerve and cholinergic agonists in immunocompromised and septic animals. These cholinergic lymphocytes re-establish splenic protection and the potential of cholinergic agonists to rescue immunocompromised animals from established sepsis. The study results revealed these new regulatory lymphocytes as, to our knowledge, the first known physiological target for neuromodulation of the innate immune responses and a potential therapeutic target for sepsis.

Impaired immune responses following spinal cord injury lead to reduced ability to control viral infection

Spinal cord injuries disrupt central autonomic pathways that regulate immune function, and increasing evidence suggests that this may cause deficiencies in immune responses in people with spinal cord injuries. Here we analyze the consequences of spinal cord injury (SCI) on immune responses following experimental viral infection of mice. Female C57BL/6 mice received complete crush injuries at either thoracic level 3 (T3) or 9 (T9), and 1 week post-injury, injured mice and un-injured controls were infected with different dosages of mouse hepatitis virus (MHV, a positive-strand RNA virus). Following MHV infection, T3- and T9-injured mice exhibited increased mortality in comparison to un-injured and laminectomy controls. Infection at all dosages resulted in significantly higher viral titer in both T3- and T9-injured mice compared to un-injured controls. Investigation of anti-viral immune responses revealed impairment of cellular infiltration and effector functions in mice with SCI. Specifically, cell-mediated responses were diminished in T3-injured mice, as seen by reduction in virus-specific CD4(+) T lymphocyte proliferation and IFN-γ production and decreased numbers of activated antigen presenting cells compared to infected un-injured mice. Collectively, these data indicate that the inability to control viral replication following SCI is not level dependent and that increased susceptibility to infection is due to suppression of both innate and adaptive immune responses.

Interleukin 2-regulated in vitro antibody production following a single spinal manipulative treatment in normal subjects

Background

Our recent investigations have demonstrated that cell cultures from subjects, who received a single spinal manipulative treatment in the upper thoracic spine, show increased capacity for the production of the key immunoregulatory cytokine, interleukin-2. However, it has not been determined if such changes influence the response of the immune effector cells. Thus, the purpose of the present study was to determine whether, in the same subjects, spinal manipulation-related augmentation of the in vitro interleukin-2 synthesis is associated with the modulation of interleukin 2-dependent and/or interleukin-2-induced humoral immune response (antibody synthesis).

Methods

A total of seventy-four age and sex-matched healthy asymptomatic subjects were studied. The subjects were assigned randomly to: venipuncture control (n = 22), spinal manipulative treatment without cavitation (n = 25) or spinal manipulative treatment associated with cavitation (n = 27) groups. Heparinized blood samples were obtained from the subjects before (baseline) and then at 20 minutes and 2 hours post-treatment. Immunoglobulin (antibody) synthesis was induced in cultures of peripheral blood mononuclear cells by stimulation with conventional pokeweed mitogen or by application of human recombinant interleukin-2. Determinations of the levels of immunoglobulin G and immunoglobulin M production in culture supernatants were performed by specific immunoassays.

Results

The baseline levels of immunoglobulin synthesis induced by pokeweed mitogen or human recombinant interleukin-2 stimulation were comparable in all groups. No significant changes in the production of pokeweed mitogen-induced immunoglobulins were observed during the post-treatment period in any of the study groups. In contrast, the production of interleukin-2 -induced immunoglobulin G and immunoglobulin M was significantly increased in cultures from subjects treated with spinal manipulation. At 20 min post-manipulation, immunoglobulin G synthesis was significantly elevated in subjects who received manipulation with cavitation, relative to that in cultures from subjects who received manipulation without cavitation and venipuncture alone. At 2 hr post-treatment, immunoglobulin M synthesis was significantly elevated in subjects who received manipulation with cavitation relative to the venipuncture group. There were no quantitative alterations within the population of peripheral blood B or T lymphocytes in the studied cultures.

Conclusion

Spinal manipulative treatment does not increase interleukin-2 -dependent polyclonal immunoglobulin synthesis by mitogen-activated B cells. However, antibody synthesis induced by interleukin-2 alone can be, at least temporarily, augmented following spinal manipulation. Thus, under certain physiological conditions spinal manipulative treatment might influence interleukin-2 -regulated biological responses.

Dendritic Cell Regulation by Cannabinoid-Based Drugs

Cannabinoid pharmacology has made important advances in recent years after the cannabinoid system was discovered. Studies in experimental models and in humans have produced promising results using cannabinoid-based drugs for the treatment of obesity and cancer, as well as neuroinflammatory and chronic inflammatory diseases. Moreover, as we discuss here, additional studies also indicates that these drugs have immunosuppressive and anti-inflammatory properties including modulation of immune cell function. Thus, manipulation of the endocannabinoid system in vivo may provide novel therapeutic strategies against inflammatory disorders. At least two types of cannabinoid receptors, cannabinoid 1 and cannabinoid 2 receptors are expressed on immune cells such as dendritic cells (DC). Dendritic cells are recognized for their critical role in initiating and maintaining immune responses. Therefore, DC are potential targets for cannabinoid-mediated modulation. Here, we review the effects of cannabinoids on DC and provide some perspective concerning the therapeutic potential of cannabinoids for the treatment of human diseases involving aberrant inflammatory processes.

α2-Adrenergic Receptors Are Present in Normal Human Conjunctiva

PURPOSE

Despite the passage of medications, including antiglaucoma drugs, through the ocular surface, and despite the increasing relevance of neurogenic inflammation in the ocular surface, the presence of some neuroreceptors in the conjunctiva has not been ascertained. This study describes the presence of alpha2-adrenergic receptors in normal human conjunctiva.

METHODS

Immunofluorescence microscopy, electrophoresis, and Western blot analyses were done in human conjunctival biopsies and rat control tissues. Antibodies against alpha2-adrenergic receptor subtypes alpha2A, alpha2B, and alpha2C were used.

RESULTS

Immunoreactivity for alpha2A- and alpha2B-, but not alpha2C-adrenergic receptors was evenly distributed in epithelial cells of human conjunctiva cryosections. Immunoreactive bands were detected for the three alpha2-adrenergic receptor subtypes: a major band of 48-50 kDa and fellow bands of 65-67 kDa.

CONCLUSIONS

Normal human conjunctival epithelial cells express alpha2A-, alpha2B-, and alpha2C-adrenergic receptors. Further studies to determine the functional implications of these receptors in ocular surface homeostasis are warranted.