Cytokines and the immune–neuroendocrine network: What did we learn from infection and autoimmunity?

Decreased Systemic Monocyte Colony Protein-1 (MCP-1) Levels and Reduced sCD14 Levels in Curcumin-Treated Patients with Moderate Anxiety: A Pilot Study

Psychosocial stress may alter cortisol and/or affect the normal functioning of the immune system. Curcuminoids can promote beneficial effects in neuropsychiatric diseases. We evaluated whether curcumin supplementation for 15 consecutive days (1800 mg/day) would decrease systemic MCP-1, sCD14, and TNF alpha levels in patients with moderate anxiety (n = 81). A total number of 81 subjects were enrolled in this study, divided into the following groups according to their Hamilton scores: a control group including patients without anxiety who were not taking curcumin (Cont, n = 22) and an anxiety group including patients with moderate anxiety (Anx, n = 22). The curcumin-treated patients experienced moderate anxiety, and they take curcumin for 15 consecutive days (Anx-Cur (after), n = 15, 1800 mg/day). An evaluation of 128 patients was conducted, which allowed for their assignment to the study groups according to their scores on Hamilton scale II. The cortisol levels were quantified in salivary samples through ELISA (ng/mL), and malonaldehyde (MDA) levels were measured in plasma via the TBARS assay as an index of lipoperoxidation. Several systemic proinflammatory cytokines (pg/mL: MCP-1, TNF alpha, IL-1 beta) and mediators were quantified through ELISA (pg/mL), including systemic sCD14 levels as a marker of monocyte activation. A two-way bifactorial ANOVA was conducted to evaluate the contributions of the anxiety factor (Anx) and/or curcumin factor (Cur) in all the tested markers, including interactions between both factors. High systemic MCP-1 and elevated sCD14 levels were observed in patients with moderate anxiety, which were reduced with curcumin supplementation. In addition, curcumin prevented cortisol overexpression and decreased MDA levels as an antioxidant response in these patients. Collectively, curcumin presented anti-chemotactic effects by reducing systemic MCP-1 levels in anxiety. Curcumin decreased systemic MCP-1 as well as sCD14 levels in patients with moderate anxiety.

A mitochondrial nexus in major depressive disorder: Integration with the psycho-immune-neuroendocrine network

Nervous system processes, including cognition and affective state, fundamentally rely on mitochondria. Impaired mitochondrial function is evident in major depressive disorder (MDD), reflecting cumulative detrimental influences of both extrinsic and intrinsic stressors, genetic predisposition, and mutation. Glucocorticoid 'stress' pathways converge on mitochondria; oxidative and nitrosative stresses in MDD are largely mitochondrial in origin; both initiate cascades promoting mitochondrial DNA (mtDNA) damage with disruptions to mitochondrial biogenesis and tryptophan catabolism. Mitochondrial dysfunction facilitates proinflammatory dysbiosis while directly triggering immuno-inflammatory activation via released mtDNA, mitochondrial lipids and mitochondria associated membranes (MAMs), further disrupting mitochondrial function and mitochondrial quality control, promoting the accumulation of abnormal mitochondria (confirmed in autopsy studies). Established and putative mechanisms highlight a mitochondrial nexus within the psycho-immune neuroendocrine (PINE) network implicated in MDD. Whether lowering neuronal resilience and thresholds for disease, or linking mechanistic nodes within the MDD pathogenic network, impaired mitochondrial function emerges as an important risk, a functional biomarker, providing a therapeutic target in MDD. Several treatment modalities have been demonstrated to reset mitochondrial function, which could benefit those with MDD.

Association between T-tau protein and Aβ42 in plasma neuronal-derived exosomes and cognitive impairment in patients with permanent atrial fibrillation and the role of anticoagulant therapy and inflammatory mechanisms

BACKGROUND

This study explores whether the differences in cognitive performance among individuals with permanent atrial fibrillation (AF) are attributable to the duration of AF and anticoagulant therapy and explores the possible inflammatory mechanism of cognitive dysfunction related to AF.

METHODS

A total of 260 patients aged 50-75 years without previous cerebrovascular events were enrolled in this study. These 260 patients had been divided into the AF group (140 patients) and sinus rhythm group (120 patients). In the AF group, we divided participants into cognitive impairment (CI) group (90 patients) and cognitive normal (CN) group (50 patients). In the sinus rhythm group, we also divided participants into CI group (61 patients) and CN group (59 patients). The Mini-Mental State Examination (MMSE) was used to assess the cognitive function of all participants. Neuronal-derived exosomes were enriched in peripheral blood by immunoprecipitation and were confirmed by a transmission electron microscope, nanoparticle tracking analysis, and western blot. Alzheimer's disease-pathogenic exosomal proteins and inflammatory cytokines were quantified. The association between AF and cognitive function was estimated by logistic regression analysis. ANOVA or Welch's t-test compared the difference in protein concentrations between groups.

RESULTS

Non-anticoagulant therapy in patients with AF was significantly associated with CI (OR = 13.99, 95% CI: 2.67-73.36, p < .01). The incidence of dementia in patients with AF > 3 years was significantly higher than in patients with AF ≤ 3 years, but there was no significant difference in total cognitive dysfunction (mild cognitive impairment [MCI] + dementia) (p = .126). The adjusted exosome concentrations of T-tau and amyloid-β protein 42 (Aβ42) in the CI group were significantly higher than in the CN group (p < .001). The serum concentrations of IL-6 and matrix metalloproteinase-9 (MMP-9) in patients with AF were higher than those in patients with sinus rhythm (p <  .001).

CONCLUSION

Aβ42 and T-tau in peripheral blood neuronal-derived exosomes maybe be associated with the early diagnosis of CI in patients with permanent AF. However, the value of Aβ42 and T-tau for CI in patients with permanent AF still needs to be confirmed in future randomized control trials.

Probiotic consumption during puberty mitigates LPS-induced immune responses and protects against stress-induced depression- and anxiety-like behaviors in adulthood in a sex-specific manner

Puberty/adolescence is a significant period of development and a time with a high emergence of psychiatric disorders. During this period, there is increased neuroplasticity and heightened vulnerability to stress and inflammation. The gut microbiome regulates stress and inflammatory responses and can alter brain chemistry and behaviour. However, the role of the gut microbiota during pubertal development remains largely uninvestigated. The current study examined gut manipulation with probiotics during puberty in CD1 mice on lipopolysaccharide (LPS)-induced immune responses and enduring effects on anxiety- and depression-like behaviours and stress-reactivity in adulthood. Probiotics reduced LPS-induced sickness behaviour at 12 h in females and at 48 h following LPS treatment in males. Probiotics also reduced LPS-induced changes in body weight at 48 h post-treatment in females. Probiotic treatment also prevented LPS-induced increases in pro- and anti-inflammatory peripheral cytokines at 8 h following LPS treatment, reduced central cytokine mRNA expression in the hypothalamus, hippocampus and PFC, and prevented LPS-induced changes to in the gut microbiota. A single exposure to LPS during puberty resulted in enduring depression-like behaviour in female mice, and anxiety-like behaviour in male mice in adulthood. However, pubertal exposure to probiotics prevented enduring LPS-induced depression-like behaviour in females and anxiety-like behaviors in males. Moreover, probiotics altered toll-like receptor-4 activity in the paraventricular nucleus of the hypothalamus (PVN) in males in response to a novel stressor in adulthood. Our results suggest that the gut microbiome plays an important role in pubertal neurodevelopment. These findings indicate that exposure to probiotics during puberty mitigates inflammation and decreases stress-induced vulnerabilities to emotional behaviours later in life, in a sex-specific manner.

Health, pre-disease and critical transition to disease in the psycho-immune-neuroendocrine network: Are there distinct states in the progression from health to major depressive disorder?

The psycho-immune-neuroendocrine (PINE) network is a regulatory network of interrelated physiological pathways that have been implicated in major depressive disorder (MDD). A model of disease progression for MDD is presented where the stable, healthy state of the PINE network (PINE physiome) undergoes progressive pathophysiological changes to an unstable but reversible pre-disease state (PINE pre-diseasome) with chronic stress. The PINE network may then undergo critical transition to a stable, possibly irreversible disease state of MDD (PINE pathome). Critical transition to disease is heralded by early warning signs which are detectible by biomarkers specific to the PINE network and may be used as a screening test for MDD. Critical transition to MDD may be different for each individual, as it is reliant on diathesis, which comprises genetic predisposition, intrauterine and developmental factors. Finally, we propose the PINE pre-disease state may form a "universal pre-disease state" for several non-communicable diseases (NCDs), and critical transition of the PINE network may lead to one of several frequently associated disease states (influenced by diathesis), supporting the existence of a common Chronic Illness Risk Network (CIRN). This may provide insight into both the puzzle of multifinality and the growing clinical challenge of multimorbidity.

Determination of dehydroepiandrosterone and its biologically active oxygenated metabolites in human plasma evinces a hormonal imbalance during HIV-TB coinfection

An estimated one third of the world's population is affected by latent tuberculosis (TB), which once active represents a leading cause of death among infectious diseases. Human immunodeficiency virus (HIV) infection is a main predisposing factor to TB reactivation. Individuals HIV-TB co-infected develop a chronic state of inflammation associated with hypothalamic-pituitary-adrenal (HPA) axis dysregulation. This results in a hormonal imbalance, disturbing the physiological levels of cortisol and dehydroepiandrosterone (DHEA). DHEA and its oxygenated metabolites androstenediol (AED), androstenetriol (AET) and 7-oxo-DHEA are immunomodulatory compounds that may regulate physiopathology in HIV-TB co-infection. In order to study possible changes in plasma levels of these hormones, we developed an approach based on high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). To our knowledge, this represents the first report of their simultaneous measurement in HIV-TB individuals and the comparison with healthy donors, obtaining statistically higher plasma levels of DHEA, AET and 7-oxo-DHEA in patients. Moreover, we found that concentrations of 7-oxo-DHEA positively correlated with absolute CD4+ T cell counts, nadir CD4+ T cell values and with individuals who presented TB restricted to the lungs. This research contributes to understanding the role of these hormones in HIV-TB and emphasizes the importance of deepening their study in this context.

Altered Neuroendocrine Immune Responses, a Two-Sword Weapon against Traumatic Inflammation

During the occurrence and development of injury (trauma, hemorrhagic shock, ischemia and hypoxia), the neuroendocrine and immune system act as a prominent navigation leader and possess an inter-system crosstalk between the reciprocal information dissemination. The fundamental reason that neuroendocrinology and immunology could mix each other and permeate toward the field of traumatology is owing to their same biological languages or chemical information molecules (hormones, neurotransmitters, neuropeptides, cytokines and their corresponding receptors) shared by the neuroendocrine and immune systems. The immune system is not only modulated by the neuroendocrine system, but also can modulate the biological functions of the neuroendocrine system. The interactive linkage of these three systems precipitates the complicated space-time patterns for the courses of traumatic inflammation. Recently, compelling evidence indicates that the network linkage pattern that initiating agents of neuroendocrine responses, regulatory elements of immune cells and effecter targets for immune regulatory molecules arouse the resistance mechanism disorders, which supplies the beneficial enlightenment for the diagnosis and therapy of traumatic complications from the view of translational medicine. Here we review the alternative protective and detrimental roles as well as possible mechanisms of the neuroendocrine immune responses in traumatic inflammation.

miR-30c is specifically repressed in patients with active pulmonary tuberculosis

Tuberculous pleurisy (PLTB) is a common form of extrapulmonary tuberculosis. It often resolves without chemotherapy being hence considered a rather benign manifestation of the disease. Patients with PLTB mount an effective anti-mycobacterial response, unlike those with active pulmonary TB (pTB) that were shown to present an imbalance in plasma immune and endocrine mediators. In this work, we explored whether expression of the active isoform of the glucocorticoid receptor (hGRα) in the context of the inflammatory-anti-inflammatory responses of TB patients may be associated to microRNA levels. As expected, the inflammatory response triggered in patients coexists with increased circulating cortisol and altered hGRα levels in the peripheral blood mononuclear cells. However, while hGRα expression is significantly downregulated in PLTB, its levels in pTB patients are higher within the control values. These results point out to the existence of an additional mechanism tending to preserve hGRα levels probably to deal with the chronic inflammation observed in pTB. In this regard, we found that miR-30c is strongly downregulated in mononuclear cells of pTB patients compared to PLTB cases, showing an expression profile opposite to that seen with hGRα. Interestingly, low levels of miR-30c are specific for this active form of TB, as its expression is not altered in mononuclear cells from either healthy controls or patients with tuberculous or non-tuberculous pleurisy. Moreover, miR-30c and hGRα also showed an inverse expression pattern in M. tuberculosis-stimulated THP-1 macrophage cultures. In sum, our studies identify miR-30c as a specific correlate of pulmonary manifestations of TB, potentially involved in the altered glucocorticoid sensitivity observed in these patients.

The immunomodulatory role of the hypothalamus-pituitary-gonad axis: Proximate mechanism for reproduction-immune trade offs?

The present review discusses the communication between the hypothalamic-pituitary-gonad (HPG) axis and the immune system of vertebrates, attempting to situate the HPG-immune interaction into the context of life history trade-offs between reproductive and immune functions. More specifically, (i) we review molecular and cellular interactions between hormones of the HPG axis, and, as far as known, the involved mechanisms on immune functions, (ii) we evaluate whether the HPG-immune crosstalk serves as proximate mechanism mediating reproductive-immune trade-offs, and (iii) we ask whether the nature of the HPG-immune interaction is conserved throughout vertebrate evolution, despite the changes in immune functions, reproductive modes, and life histories. In all vertebrate classes studied so far, HPG hormones have immunomodulatory functions, and indications exist that they contribute to reproduction-immunity resource trade-offs, although the very limited information available for most non-mammalian vertebrates makes it difficult to judge how comparable or different the interactions are. There is good evidence that the HPG-immune crosstalk is part of the proximate mechanisms underlying the reproductive-immune trade-offs of vertebrates, but it is only one factor in a complex network of factors and processes. The fact that the HPG-immune interaction is flexible and can adapt to the functional and physiological requirements of specific life histories. Moreover, the assumption of a relatively fixed pattern of HPG influence on immune functions, with, for example, androgens always leading to immunosuppression and estrogens always being immunoprotective, is probably oversimplified, but the HPG-immune interaction can vary depending on the physiological and envoironmental context. Finally, the HPG-immune interaction is not only driven by resource trade-offs, but additional factors such as, for instance, the evolution of viviparity shape this neuroendocrine-immune relationship.

The effects of ryanodine receptor (RYR1) mutation on natural killer cell cytotoxicity, plasma cytokines and stress hormones during acute intermittent exercise in pigs

Stress susceptibility has been mapped to a single recessive gene, the ryanodine receptor 1 (RYR1) gene or halothane (Hal) gene. Homozygous (Hal(nn)), mutated pigs are sensitive to halothane and susceptible to Porcine Stress Syndrome (PSS). Previous studies have shown that stress-susceptible RYR1 gene mutated homozygotes in response to restraint stress showed an increase in natural killer cell cytotoxicity (NKCC) accompanied by more pronounced stress-related hormone and anti-inflammatory cytokine changes. In order to determine the relationship of a RYR1 gene mutation with NKCC, plasma cytokines and stress-related hormones following a different stress model - exercise - 36 male pigs (representing different genotypes according to RYR1 gene mutation: NN, homozygous dominant; Nn, heterozygous; nn, homozygous recessive) were submitted to an intermittent treadmill walking. During the entire experiment the greatest level of NKCC and the greatest concentrations of interleukin (IL-) 6, IL-10, IL-12, interferon (IFN-)γ and tumor necrosis factor-α and stress-related hormones (adrenaline, prolactin, beta-endorphin) were observed in nn pigs, and the greatest concentration of IL-1 and growth hormone in NN pigs. Immunostimulatory effects of intermittent exercise on NKCC in nn pigs were concomitant with increases in IL-2, IL-12 and IFN-γ, the potent NKCC activators. Our findings suggest that stress-susceptible pigs RYR1 gene mutated pigs develop a greater level of NKCC and cytokine production in response to exercise stress. These results suggest that the heterogeneity of immunological and neuroendocrine response to exercise stress in pigs could be influenced by RYR1 gene mutation.

Quantitative Analysis of Intestinal Flora of Uygur and Han Ethnic Chinese Patients with Ulcerative Colitis

Aim. To study the correlation between intestinal flora and ulcerative colitis by analyzing the abundance of Bacteroides, Fusobacterium, Clostridium, Bifidobacterium spp., and Faecalibacterium prausnitzii in the intestinal of ulcerative colitis (UC) patients and healthy controls with Uygur and Han ethnic. Methods. Bacterial genomic DNA was extracted from fecal samples and analyzed with real-time fluorescence quantitative polymerase chain reaction (PCR) to identify the abundance of Bacteroides, Fusobacterium, Clostridium, Bifidobacterium spp., and Faecalibacterium prausnitzii. Results. The samples from UC patients, Uygur and Han ethnic combined, had higher abundance of Bacteroides (P = 0.026) but lower Clostridium (P = 0.004), Bifidobacterium spp. (P = 0.009), and Faecalibacterium prausnitzii (P = 0.008) than those from healthy controls. Among UC patients, Bacteroides population was raised in acute UC patients (P ≤ 0.05), while the abundance of Clostridium, Bifidobacterium spp., Fusobacterium, and Faecalibacterium prausnitzii decreased (P ≤ 0.05) compared with the remission. In both UC patients group and control group, no difference was observed in the abundance of these 5 bacteria between the Han and the Uygur group. Conclusions. Variations in the abundance of these five bacterial strains in intestines may be associated with the occurrence of UC in Uygur and Han populations; however, these variations were not associated with ethnic difference.

Inflammation and Nutritional Science for Programs/Policies and Interpretation of Research Evidence (INSPIRE)

An increasing recognition has emerged of the complexities of the global health agenda—specifically, the collision of infections and noncommunicable diseases and the dual burden of over- and undernutrition. Of particular practical concern are both 1) the need for a better understanding of the bidirectional relations between nutritional status and the development and function of the immune and inflammatory response and 2) the specific impact of the inflammatory response on the selection, use, and interpretation of nutrient biomarkers. The goal of the Inflammation and Nutritional Science for Programs/Policies and Interpretation of Research Evidence (INSPIRE) is to provide guidance for those users represented by the global food and nutrition enterprise. These include researchers (bench and clinical), clinicians providing care/treatment, those developing and evaluating programs/interventions at scale, and those responsible for generating evidence-based policy. The INSPIRE process included convening 5 thematic working groups (WGs) charged with developing summary reports around the following issues: 1) basic overview of the interactions between nutrition, immune function, and the inflammatory response; 2) examination of the evidence regarding the impact of nutrition on immune function and inflammation; 3) evaluation of the impact of inflammation and clinical conditions (acute and chronic) on nutrition; 4) examination of existing and potential new approaches to account for the impact of inflammation on biomarker interpretation and use; and 5) the presentation of new approaches to the study of these relations. Each WG was tasked with synthesizing a summary of the evidence for each of these topics and delineating the remaining gaps in our knowledge. This review consists of a summary of the INSPIRE workshop and the WG deliberations.

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.

Epinephrine enhances the response of macrophages under LPS stimulation

Trauma associated with infection may directly trigger a neuroendocrine reaction in vivo while the hormone epinephrine is known to mediate immune responses to inflammation after injury. However, the role of epinephrine during the earliest stage of trauma still remains unclear. We therefore explored the role of epinephrine on activated macrophages under LPS stimulation in vitro as well as the mechanisms underlying its effect. Dose- and time-dependent effects of epinephrine on macrophage immune function were assessed after LPS activation. We also employed CD14 siRNA interference to investigate whether CD14 played a role in the mechanism underlying the effect of epinephrine on LPS-induced macrophage responses. Our results showed that epinephrine pretreatment (10 ng/mL) significantly promoted immune responses from LPS stimulated macrophages, including phagocytic rate, phagocytic index, TNFα/IL-1β/IL-10 secretion, and CD14 expression (P < 0.05). Moreover, TNFα/IL-1β/IL-10 levels attained their peak value 1 hour after incubation with 10 ng/mL epinephrine (P < 0.05), and CD14 siRNA transfection dramatically decreased phagocytosis and cytokine secretion by LPS-activated macrophages (P < 0.05). We therefore conclude that 10 ng/mL epinephrine enhances immune responses from macrophages under LPS stimulation and that the underlying mechanism may relate to CD14 upregulation on the surface of macrophages.

Molecular and cellular neuroinflammatory status of mouse brain after systemic lipopolysaccharide challenge: importance of CCR2/CCL2 signaling

Background

Genetic and environmental factors are critical elements influencing the etiology of major depression. It is now accepted that neuroinflammatory processes play a major role in neuropsychological disorders. Neuroinflammation results from the dysregulation of the synthesis and/or release of pro- and anti-inflammatory cytokines with central or peripheral origin after various insults. Systemic bacterial lipopolysaccharide (LPS) challenge is commonly used to study inflammation-induced depressive-like behaviors in rodents. In the present study, we investigated immune-to-brain communication in mice by examining the effects of peripheral LPS injection on neuroinflammation encompassing cytokine and chemokine production, microglia and central nervous system (CNS)-associated phagocyte activation, immune cell infiltration and serotonergic neuronal function.

Methods

LPS was administered to C57BL/6 J mice by intraperitoneal injection; brains were collected and pro-inflammatory cytokine mRNA and proteins were measured. To examine the relative contribution of the different populations of brain immune cells to the occurrence of neuroinflammation after acute systemic inflammation, we precisely characterized them by flow cytometry, studied changes in their proportions and level of activation, and measured the amount of cytokines they released by Cytometric Bead Array™ after cell sorting and ex vivo culture. Because of the central role that the chemokine CCL2 seems to play in our paradigm, we studied the effect of CCL2 on the activity of serotonergic neurons of the raphe nucleus using electrophysiological recordings.

Results

We report that systemic LPS administration in mice caused a marked increase in pro-inflammatory IL-1β, IL-6, TNFα and CCL2 (monocyte chemoattractant protein-1) mRNA and protein levels in the brain. Moreover, we found that LPS caused microglia and CNS-associated phagocyte activation characterized by upregulation of CCR2, TLR4/CD14, CD80 and IL-4Rα, associated with overproduction of pro-inflammatory cytokines and chemokines, especially CCL2. LPS also induced a marked and selective increase of CCR2⁺ inflammatory monocytes within the brain. Finally, we showed that CCL2 hyperpolarized serotonergic raphe neurons in mouse midbrain slices, thus probably reducing the serotonin tone in projection areas.

Conclusion

Together, we provide a detailed characterization of the molecular and cellular players involved in the establishment of neuroinflammation after systemic injection of LPS. This highlights the importance of the CCL2/CCR2 signaling and suggests a possible link with depressive disorders.

The effects of ryanodine receptor 1 (RYR1) mutation on plasma cytokines and catecholamines during prolonged restraint in pigs

In the current study, plasma cytokines, including interleukin (IL) 1, IL-2, IL-6, IL-10, IL-12, interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) and catecholamines (adrenaline and noradrenaline) were evaluated during 4h restraint and recovery phase in 60 male pigs. Blood samples were collected from three groups of pigs representing different RYR1 genotypes, namely NN homozygotes (wild-type), Nn heterozygous and nn homozygous (mutant). The 4h restraint evoked an increase in plasma cytokine concentrations in each of the RYR1 genotype groups. During the restraint, the greatest concentrations of plasma IL-6, IL-10, IL-12 and TNF-α in nn homozygous pigs and IFN-γ in NN homozygous were observed. Interleukin 1, IL-2, IL-10, and TNF-α measures were positively intercorrelated in each of the three RYR1 genotype group. A positive correlation was seen between all measured cytokines (with the exception of IL-6) and plasma catecholamine concentrations in Nn heterozygous and nn homozygous pigs. The results suggest that of the cytokine parameters evaluated, IL-6, IL-10, IL-12 and TNF-α of the nn homozygous group seem to show a stronger stress-related response as compared with those of the other two (NN and Nn) groups.

Comparison of the cytokine and chemokine dynamics of the early inflammatory response in models of burn injury and infection

The inflammatory response, and its subsequent resolution, are the result of a very complex cascade of events originating at the site of injury or infection. When the response is severe and persistent, Systemic Inflammatory Response Syndrome can set in, which is associated with a severely debilitating systemic hypercatabolic state. This complex behavior, mediated by cytokines and chemokines, needs to be further explored to better understand its systems properties and potentially identify multiple targets that could be addressed simultaneously. In this context, short term responses of serum cytokines and chemokines were analyzed in two types of insults: rats receiving a "sterile" cutaneous dorsal burn on 20% of the total body surface area (TBSA); rats receiving a cecum ligation and puncture treatment (CLP) to induce infection. Considering the temporal variability observed in the baseline corresponding to the control group, the concept of area under the curve (AUC) was explored to assess the dynamic responses of cytokines and chemokines. MCP-1, GROK/KC, IL-12, IL-18 and IL-10 were observed in both burn and CLP groups. While IL-10 concentration was only increased in the burn group, Eotaxin was only elevated in CLP group. It was also observed that Leptin and IP-1 concentrations were decreased in both CLP and sham-CLP groups. The link between the circulating protein mediators and putative transcription factors regulating the cytokine/chemokine gene expression was explored by searching the promoter regions of cytokine/chemokine genes in order to characterize and differentiate the inflammatory responses based on the dynamic data. Integrating multiple sources together with the bioinformatics tools identified mediators sensitive to type and extent of injury, and provided putative regulatory mechanisms. This is essential to gain a better understanding for the important regulatory points that can be used to modulate the inflammatory state at molecular level.

Eriobotrya japonica hydrophilic extract modulates cytokines in normal tissues, in the tumor of Meth-A-fibrosarcoma bearing mice, and enhances their survival time

Background

Cytokines play a key role in the immune response to developing tumors, and therefore modulating their levels and actions provides innovative strategies for enhancing the activity of antigen presenting cells and polarizing towards T helper 1 type response within tumor microenvironment. One of these approaches could be the employment of plant extracts that have cytokine immunomodulation capabilities. Previously, we have shown that the Eriobotrya japonica hydrophilic extract (EJHE) induces proinflammatory cytokines in vitro and in vivo.

Methods

The present study explored the in vivo immunomodulatory effect on interferon-gamma (IFN-γ), interleukin-17 (IL-17), and transforming growth factor-beta 1 (TGF-β1) evoked by two water-extracts prepared from EJ leaves in the tissues of normal and Meth-A-fibrosarcoma bearing mice.

Results

Intraperitoneal (i.p.) administration of 10 μg of EJHE and EJHE-water residue (WR), prepared from butanol extraction, increased significantly IFN-γ production in the spleen (p < 0.01) and lung (p < 0.03) tissues at 6-48 hours and suppressed significantly TGF-β1 production levels (p < 0.001) in the spleen for as long as 48 hours. The latter responses, however, were not seen in Meth-A fibrosarcoma-bearing mice. On the contrary, triple i.p. injections, 24 hours apart; of 10 μg EJHE increased significantly IFN-γ production in the spleen (p < 0.02) while only EJHE-WR increased significantly IFN-γ, TGF-β1 and IL-17 (p < 0.03 - 0.005) production within the tumor microenvironment of Meth-A fibrosarcoma. In addition, the present work revealed a significant prolongation of survival time (median survival time 72 days vs. 27 days of control, p < 0.007) of mice inoculated i.p. with Meth-A cells followed by three times/week for eight weeks of i.p. administration of EJHE-WR. The latter prolonged survival effect was not seen with EJHE.

Conclusions

The therapeutic value of EJHE-WR as an anticancer agent merits further investigation of understanding the effect of immunomodulators' constituents on the cellular components of the tissue microenvironment. This can lead to the development of improved strategies for cancer treatment and thus opening up a new frontier for future studies.

Infection, immunity and the neuroendocrine response

The Central Nervous (CNS) and Immune Systems (IS) are the two major adaptive systems which respond rapidly to numerous challenges that are able to compromise health. The defensive response strictly linking innate to acquired immunity, works continuously to limit pathogen invasion and damage. The efficiency of the innate response is crucial for survival and for an optimum priming of acquired immunity. During infection, the immune response is modulated by an integrated neuro-immune network which potentiates innate immunity, controls potential harmful effects and also addresses metabolic and nutritional modifications supporting immune function. In the last decade much knowledge has been gained on the molecular signals that orchestrate this integrated adaptive response, with focus on the systemic mediators which have a crucial role in driving and controlling an efficient protective response. These mediators are also able to signal alterations and control pathway dysfunctions which may be involved in the persistence and/or overexpression of inflammation that may lead to tissue damage and to a negative metabolic impact, causing retarded growth. This review aims to describe some important signalling pathways which drive bidirectional communication between the Immune and Nervous Systems during infection. Particular emphasis is placed on pro-inflammatory cytokines, immunomodulator hormones such as Glucocorticoids (GCs), Growth hormone (GH), Insulin-like Growth Factor-1 (IGF-1), and Leptin, as well as nutritional factors such as Zinc (Zn). Finally, the review includes up-to-date information on this neuroimmune cross-talk in domestic animals. Data in domestic animal species are still limited, but there are several exciting areas of research, like the potential interaction pathways between mediators (i.e. cytokine-HPA regulation, IL-6-GCS-Zn, cytokines-GH/IGF-1, IL-6-GH-Leptin and thymus activity) that are or could be promising topics of future research in veterinary medicine.

The corticotropin-releasing factor system in inflammatory bowel disease: prospects for new therapeutic approaches

Mounting evidence suggests that stress is implicated in the development of inflammatory bowel disease (IBD), via initial nervous disturbance and subsequent immune dysfunction through brain-gut interactions. The corticotropin-releasing factor (CRF) system, being the principal neuroendocrine coordinator of stress responses, is involved in the inflammatory process within the gastrointestinal tract, via vagal and peripheral pathways, as implied by multiple reports reviewed here. Blocking of CRF receptors could theoretically exert beneficial anti-inflammatory effects in colonic tissues. The recently synthesised small-molecule CRF(1) antagonists or alternatively non-peptide CRF(2) antagonists when available, may become new reliable options in the treatment of IBD.

MCP-1-deficient mice show reduced neuroinflammatory responses and increased peripheral inflammatory responses to peripheral endotoxin insult

BACKGROUND

An endotoxin insult mimics a severe peripheral infection and recent evidence suggests that a single exposure can cause long-term cognitive deficits. A peripheral injection of LPS results in production of pro-inflammatory cytokines, such as IL-1beta and TNF-alpha, in the brain and periphery and these cytokines mediate many effects of the acute phase response including activation of the HPA axis. The chemokine MCP-1 is highly expressed during endotoxemia and although much is known about the importance of MCP-1 in peripheral inflammatory responses to LPS, information about MCP-1 and CNS responses to peripheral LPS is lacking.

METHODS

C57Bl/6 mice were administered LPS by intraperitoneal (i.p.) injection, serum and brains were collected at several time points, and the time course of MCP-1 protein up-regulation was measured. To examine the role of MCP-1 in activation of the brain during acute systemic inflammation, we injected MCP-1 knockout (MCP-1-/-) or control C57Bl/6 (MCP-1+/+) mice with LPS i.p. and measured the levels of selected cytokines and chemokines in serum and brain extracts 6 hours later. Activated microglia were examined by CD45 immunohistochemistry, and serum corticosterone and ACTH levels were measured by enzyme immunoassay.

RESULTS

We report that LPS injection induces a robust increase in MCP-1 protein levels in serum and brain, with peak brain levels reached at 6 hrs after LPS administration. MCP-1-/- mice injected with LPS showed higher levels of serum IL-1beta and TNF-alpha compared to LPS-treated MCP-1+/+ mice. In contrast, these MCP-1-/- mice showed significantly lower inductions of brain pro-inflammatory cytokines and chemokines, fewer activated microglia, and a reduction in serum corticosterone levels.

CONCLUSION

MCP-1-/- mice have decreased brain inflammation after a peripheral LPS insult, despite an exaggerated peripheral response. These data demonstrate an important role for MCP-1 in regulation of brain inflammation after peripheral endotoxemia.

On the mechanisms and putative pathways involving neuroimmune interactions

Bidirectional interdependence between the immune system and the CNS involves the intervention of common cofactors. Cytokines are endogenous to the brain, endocrine and immune systems. These shared ligands are used as a chemical language for communication. Such interaction suggests an immunoregulatory role for the brain, and a sensory function for the immune system. Interplay between the immune, nervous and endocrine systems is associated with effects of stress on immunity. Cytokines are thus capable of modulating responses in the CNS, while neuropeptides can exert their effects over cellular groups in the immune system. One way is controlled by the HPA axis, a coordinator of neuroimmune interactions that is essential to unravel in order to elucidate vital communications in a manner that this crosstalk remains a cornerstone in perpetuating a stance of homeostasis.

TNFalpha: a trigger of autonomic dysfunction

During disease, infection, or trauma, the cytokine tumor necrosis factor alpha (TNF alpha) causes fever, fatigue, malaise, allodynia, anorexia, gastric stasis associated with nausea, and emesis via interactions with the central nervous system. Our studies have focused on how TNF alpha produces a profound gastric stasis by acting on vago-vagal reflex circuits in the brainstem. Sensory elements of this circuit (i.e., nucleus of the solitary tract [NST] and area postrema) are activated by TNF alpha. In response, the efferent elements (i.e., dorsal motor neurons of the vagus) cause gastroinhibition via their action on the gastric enteric plexus. We find that TNF alpha presynaptically modulates the release of glutamate from primary vagal afferents to the NST and can amplify vagal afferent responsiveness by sensitizing presynaptic intracellular calcium-release mechanisms. The constitutive presence of TNF alpha receptors on these afferents and their ability to amplify afferent signals may explain how TNF alpha can completely disrupt autonomic control of the gut.