Vagus nerve stimulation attenuates the systemic inflammatory response to endotoxin

Carbachol alleviates oxygen free radical injury in gut during enteral resuscitation of burn shock in rats

AIM: To investigate the effects of carbachol on oxygen free radical injury in gut during enteral resuscitation of burn shock in rats.

METHODS: A 35% TBSA full thickness scald injury was induced in 38 Wistar rats. The rats were divided randomly into four groups: scald with no therapy (scald alone, n = 8), scald with enteral infusing either a glucose electrolyte solution (GES, n = 10) or GES containing carbachol (60 μg/kg, GES/CAR, n = 10), and scald with enteral infusing only carbachol (CAR, n = 10). GES was infused into intestine through a duodenal stomy according to Parkland formula (4 mL·1%TBSA/kg) 30 min after scald and carbachol was administered simultaneously through the same path. Four hours after injury, the initial jejunum was collected for evaluation of xanthine oxidase (XOD), malondialdehyde (MDA), myeloperoxidase (MPO) and assessment of the pathologic damages.

RESULTS: The activity of XOD and MPO, and the MDA level were 13.2%, 21.3% and 21.1% higher in the GES containing carbachol treatment groups than in the scald alone group (P < 0.05). Resuscitation with GES/CAR resulted in significantly lower levels of XOD (1.36 ± 0.37 vs 2.51 ± 0.56, P < 0.01), MDA (3.97 ± 1.57 vs 6.59 ± 1.50, P < 0.01) and MPO (0.47 ± 0.14 vs 0.83 ± 0.21, P < 0.01) than resuscitation with GES. The parameters in the CAR group were the lowest. The gut lesions were mild in the CAR and GES/CAR groups, severe in the CAR alone group, and most severe in the GES group.

CONCLUSION: Carbachol can alleviate gut oxygen free radical injury during enteral resuscitation of burn shock, which might be associated with its anti-inflammation effects, inhibition of XOD activity and generation of oxygen free radicals in gut tissue.

Cytokines and cholinergic signals co-modulate surgical stress-induced changes in mood and memory

Inflammatory cytokines and the cholinergic system have been implicated in the effects of stressors on mood and memory; however, the underlying mechanisms involved and the potential interrelationships between these pathways remain unclear. To address these questions, we administered neuropsychological tests to 33 generally healthy surgery patients who donated blood samples several days prior to undergoing moderate surgery (baseline), on the morning of the surgery (i.e., a psychological stressor), and one day after surgery. Eighteen control subjects were similarly tested. Serum levels of inflammatory cytokines, acetylcholinesterase (AChE) activity, and the stressor-inducible AChE-R variant were measured. An elevation in anxiety levels, an increase in depressed mood, and a decline in declarative memory were observed on the morning of the surgery, prior to any medical intervention, and were exacerbated one day after surgery. The surgical stressor-induced elevated IL-1 beta levels, which contributed to the increased depressed mood and to the post-surgery increase in AChE-R expression. The latter increase, which was also predicted by pre-surgery AChE-R and post-surgery mood disturbances, was associated with exacerbated memory impairments induced by surgery. In addition, elevated levels of AChE-R on the morning of the surgery predicted the post-surgery elevation in IL-6 levels, which was associated with amelioration of the memory impairments induced by surgery. Taken together, these findings suggest that exposure to a surgical stressor induces a reciprocal up-regulation of AChE-R and pro-inflammatory cytokines, which are involved in regulating the surgery-induced mood and memory disturbances.

Abnormalities of cardiac autonomic nervous activity correlate with expansive coronary artery remodeling

BACKGROUND

Vagal fibres are distributed both in the perivascular connective tissue and in the adventitia around the circumference of arteries, and contribute to coronary artery dilation. The aim of the manuscript is to examine whether morphologic changes of the vessel wall due to the atherosclerotic process might be associated with autonomic nervous system dysfunction.

METHODS AND RESULTS

We studied 42 patients with single vessel disease referred for percutaneous coronary revascularization. Patients underwent intravascular ultrasound at the site of the ischemia-related artery before intervention. The autonomic nervous system activity was assessed by the analysis of heart rate variability (HRV) in the frequency domain. The high frequencies (HF) are predominantly under the influence of the parasympathetic system, while the low/high frequency (LF/HF) ratio represents an index of sympatho-vagal balance. Plaque plus media cross-sectional area was inversely related to HF components (r=-0.34, p<0.05), and directly related to LF/HF ratio (r=0.38, p<0.05). Patients with expansive remodeling showed lower HF values (0.07+/-0.06 nu versus 0.14+/-0.09 nu, p<0.01) and higher LH/HF ratio (2.1+/-1.1 versus 1.4+/-1.1; p<0.05). LF changes were independent of any morphologic features. On multivariate analyses the remodeling index was the only independent determinant of HF and LF/HF ratio.

CONCLUSIONS

Outward stretch of the vessel wall behind the plaque, as a consequence of increasing plaque size and expansive arterial remodeling is associated to autonomic dysfunction namely due to impairment of the vagal tone. It is unknown if remodeling is a cause of vagal impairment or if vagal impairment may contribute to arterial remodeling.

Pharmacologic cholinesterase inhibition improves survival in experimental sepsis

OBJECTIVE

Lethal sepsis occurs when an excessive inflammatory response evolves that cannot be controlled by physiologic anti-inflammatory mechanisms, such as the recently described cholinergic anti-inflammatory pathway. Here we studied whether the cholinergic anti-inflammatory pathway can be activated by pharmacologic cholinesterase inhibition in vivo.

DESIGN

Prospective, randomized laboratory investigation that used an established murine sepsis model.

SETTING

Research laboratory in a university hospital.

SUBJECTS

Female C57BL/6 mice.

INTERVENTIONS

Sepsis in mice was induced by cecal ligation and puncture. Animals were treated immediately with intraperitoneal injections of nicotine (400 microg/kg), physostigmine (80 microg/kg), neostigmine (80 microg/kg), or solvent three times daily for 3 days.

MEASUREMENTS AND MAIN RESULTS

Treatment with physostigmine significantly reduced lethality (p < or = .01) as efficiently as direct stimulation of the cholinergic anti-inflammatory pathway with nicotine (p < or = .05). Administration of cholinesterase inhibitors significantly down-regulated the binding activity of nuclear factor-kappaB (p < or = .05) and significantly reduced the concentration of circulating proinflammatory cytokines tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 (p < or = .001), and pulmonary neutrophil invasion (p < or = .05). Animals treated with the peripheral cholinesterase inhibitor neostigmine showed no difference compared with physostigmine-treated animals.

CONCLUSIONS

Our results demonstrate that cholinesterase inhibitors can be used successfully in the treatment of sepsis in a murine model and may be of interest for clinical use.

Posterior reversible encephalopathy syndrome after solid organ transplantation

BACKGROUND AND PURPOSE

Posterior reversible encephalopathy syndrome (PRES) is known to occur after solid organ transplantation (SOT), potentially associated with cyclosporine and tacrolimus. In this study, we assess the frequency and clinical and imaging characteristics of PRES after SOT.

MATERIALS AND METHODS

We identified 27 patients (13 men and 14 women; age range, 22-72 years) who developed PRES after SOT. Features noted included SOT subtype, incidence and timing of PRES, infection and rejection, mean arterial pressure (MAP), and toxicity brain edema.

RESULTS

PRES developed in 21 (0.49%) of 4222 patients who underwent transplantation within the study period (no significant difference among SOT subtypes). Transplantation was performed in 5 patients before the study period, and 1 patient underwent transplantation elsewhere. In consideration of all 27 patients, PRES typically developed in the first 2 months in patients who had SOT of the liver (9 of 10 patients) and was associated with cytomegalovirus (CMV), mild rejection, or systemic bacterial infection. PRES also typically developed after 1 year in patients who had SOT of the kidney (8 of 9 patients) and was associated with moderate rejection or bacterial infection. Toxicity MAP was significantly lower (P < .001) in liver transplants (average MAP, 104.8 +/- 16 mm Hg) compared with that in kidney transplants (average MAP, 143 +/- 20 mm Hg). Toxicity brain edema was significantly greater (P < .001) in patients who had liver transplants and developed PRES compared with patients who had undergone kidney transplants despite severe hypertension in those who had the kidney transplants.

CONCLUSION

Patients who had undergone SOTs have a similar low incidence of developing PRES. Differences between those who have had liver and kidney transplants included time after transplant, toxicity MAP, and PRES vasogenic edema noted at presentation. In patients who have undergone kidney transplants, severely elevated MAP was associated with reduced, not greater, brain edema.

Inflammation and ageing

An enhanced inflammatory state - i.e. "inflammatory/pathogen burden" - in the elderly on the one hand results from physiological immunosenescence and on the other hand is modified by the individual immune history: the latter is determined by sequential infectious/pathogenic events ("multiple hits"). Immunosenescence may prompt ageing of other organs. Cardiac ageing can be assessed by analysing heart rate variability. We present our hypothesis that the increasing "inflammatory/pathogen burden" of each organism during a lifetime significantly contributes to the cardiac ageing process. This hypothesis is grounded on the fact that a characteristic feature of the ageing heart - a narrowed heart rate variability - can be experimentally induced in humans by an inflammatory stimulus (endotoxin).

Cigarette smoke inhibits macrophage sensing of Gram-negative bacteria and lipopolysaccharide: relative roles of nicotine and oxidant stress

BACKGROUND AND PURPOSE

Smoking cigarettes is a major risk factor for the development of cardiovascular and respiratory disease. Moreover, smokers are more prone to infections. This has been associated with a suppression of the immune system by smoke. However, it is not clear how cigarette smoke affects the ability of immune cells to sense pathogens. Cigarette smoke contains a large number of molecules which may mediate responses on immune cells and of these, nicotine and oxidants have both been identified as inhibitory for the sensing of bacterial lipopolysaccharide (LPS). Nitric oxide synthase (NOS) and tumour necrosis factor (TNF)-alpha are both induced in macrophages on stimulation with Gram negative bacteria or LPS.

EXPERIMENTAL APPROACH

We used murine macrophages stimulated with whole heat-killed bacteria or LPS. We measured output of NO (as nitrite) and TNFalpha, NOS protein by Western blotting and cellular oxidant stress.

KEY RESULTS

Cigarette smoke extract suppressed the ability of murine macrophages to release NO, but not TNFalpha in response to whole bacteria. Cigarette smoke extract also inhibited nitric oxide synthase II protein expression in response to LPS. The effects of cigarette smoke extract on nitrite formation stimulated by LPS were unaffected by inhibition of nicotinic receptors with alpha-bungarotoxin (100 units ml(-1)). However, the effects of cigarette smoke extract on LPS-induced nitrite formation were mimicked by hydrogen peroxide and reversed by the anti-oxidants N-acetyl cysteine and glutathione.

CONCLUSIONS AND IMPLICATIONS

We suggest that cigarette smoke exerts its immunosuppressive effects through an oxidant-dependent and not a nicotine-dependent mechanism.

Frontiers in emphysema research

Chronic obstructive pulmonary disease (COPD) is a complex inflammatory disease with a myriad of pulmonary and nonpulmonary disease manifestations. COPD is a heterogeneous disease consisting of emphysematous destruction, airway inflammation, remodeling, and obstruction. Once conceptualized as a unidimensional disease isolated to the lung, it is now recognized to have significant systemic manifestations, such as osteoporosis, cardiovascular disease, and skeletal muscle wasting. As the clinical phenotypic expressions of COPD become more precisely characterized, so does the pathogenesis of this disease. Great strides are now being made in our understanding of genetic susceptibility, airway inflammation, the immune response to cigarette smoke, and inflammatory biomarkers. This review will discuss the most recent progress on selected topics in COPD pathogenesis, inflammation, and genetics. With time, we hope to expand our current understanding to predict who will develop disease and who will not, and why some patients develop particular disease phenotypes. In addition, we hope to clarify the inflammatory mechanisms involved in order to develop novel therapies and identify disease biomarkers that will lead to better tools for monitoring disease activity. Finally, we hope to develop treatments aimed at lung regeneration and repair, to reverse lung damage that has already occurred. We are optimistic that novel therapies like gene therapy and advanced antiinflammatory agents will be in our future. Judging by the progress made in the last decade, these tools may soon become a reality.

Severe Sepsis and Septic Shock

This chapter reviews the remarkable recent advances in the understanding of the molecular basis that underlies the pathophysiology of sepsis. This knowledge has improved diagnostic techniques and introduced new therapeutic agents into the standard management of patients with severe sepsis/septic shock. The current treatment regimens for sepsis are discussed, and the evidence to support each major treatment strategy is outlined in detail. Research priorities to further the optimal management of septic shock in the future are highlighted.

Review: Brain—immune communication psychoneuroimmunology of multiple sclerosis

The central nervous system (CNS) and the immune system are two extremely complex and highly adaptive systems. In the face of a real or anticipated threat, be it physical (eg, infection) or psychological (eg, psychosocial stress) in nature, the two systems act in concert to provide optimal adaptation to the demanding internal or environmental conditions. During instances of well being, the communication between these two systems is well tuned and balanced. However, a disturbed crosstalk between the CNS and the immune system is thought to play a major role in a wide series of disorders characterized by a hyporesponsive or hyperresponsive immune system. In multiple sclerosis (MS), a chronic inflammatory and neurodegenerative disease, an excess of inflammatory processes seems to be a hallmark and there is growing evidence for a disturbed communication between the CNS and the immune system as a crucial pathogenic factor. While the exact mechanisms for these phenomena are still poorly understood, the young discipline of psychoneuroimmunology (PNI), which focuses on the mechanism underlying the brain to immune crosstalk, might offer some insights into the existing pathogenic mechanisms. Findings from the field of PNI might also help to gain a better understanding regarding the origin and course of MS clinical symptoms such as fatigue and depression.

Advances in understanding sepsis

Sepsis, a systemic inflammatory response to infection, is a leading cause of death in intensive care units. Recent investigations into the pathogenesis of sepsis reveal a biphasic inflammatory process. An early phase is characterized by pro-inflammatory cytokines (e.g. tumour necrosis factor-alpha), whereas a late phase is mediated by an inflammatory high-mobility group box 1 and an anti-inflammatory interleukin-10. Inflammation aberrantly activates coagulation cascades as sepsis progresses. This dual inflammatory response concomitant with dysregulated coagulation partially accounts for unsuccessful anti-cytokine therapies that have solely targeted early pro-inflammatory mediators (e.g. tumour necrosis factor-alpha). In contrast, activated protein C, which modifies both inflammatory and coagulatory pathways, has improved survival in patients in severe sepsis. Inhibition of the late mediator high-mobility group box 1 improves survival in established sepsis in pre-clinical studies. In addition, recent advances in molecular medicine have shed light on two novel experimental interventions against sepsis. Accelerated apoptosis of lymphocytes has been shown to play an important role in organ dysfunction in sepsis and techniques to suppress apoptosis have improved survival rate in sepsis models. The vagus nerve system has also been shown to suppress innate immune response through endogenous release and exogenous administration of cholinergic agonists, ameliorating inflammation and lethality in sepsis models.

Folic acid and polyunsaturated fatty acids improve cognitive function and prevent depression, dementia, and Alzheimer's disease--but how and why?

Low blood folate and raised homocysteine concentrations are associated with poor cognitive function. Folic acid supplementation improves cognitive function. Folic acid enhances the plasma concentrations of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). EPA, DHA, and arachidonic acid (AA) are of benefit in dementia and Alzheimer's disease by up-regulating gene expression concerned with neurogenesis, neurotransmission and connectivity, improving endothelial nitric oxide (eNO) generation, enhancing brain acetylcholine levels, and suppressing the production of pro-inflammatory cytokines. EPA, DHA, and AA also form precursors to anti-inflammatory compounds such as lipoxins, resolvins, and neuroprotectin D1 (NPD1) that protect neurons from the cytotoxic action of various noxious stimuli. Furthermore, various neurotrophins and statins enhance the formation of NPD1 and thus, protect neurons from oxidative stress and prevent neuronal apoptosis Folic acid improves eNO generation, enhances plasma levels of EPA/DHA and thus, could augment the formation of NPD1. These results suggest that a combination of EPA, DHA, AA and folic acid could be of significant benefit in dementia, depression, and Alzheimer's disease and improve cognitive function.

Vagal-sparing esophagectomy

The vagal-sparing esophagectomy is associated with low mortality, reduced morbidity, and improved long-term gastrointestinal functional outcome compared with standard esophagectomy. It is the ideal operation for the management of intramucosal cancers, Barrett's with high-grade dysplasia and end-stage benign esophageal disease.

Transcutaneous vagus nerve stimulation reduces serum high mobility group box 1 levels and improves survival in murine sepsis

OBJECTIVE

Electrical vagus nerve stimulation inhibits proinflammatory cytokine production and prevents shock during lethal systemic inflammation through an alpha7 nicotinic acetylcholine receptor (alpha7nAChR)-dependent pathway to the spleen, termed the cholinergic anti-inflammatory pathway. Pharmacologic alpha7nAChR agonists inhibit production of the critical proinflammatory mediator high mobility group box 1 (HMGB1) and rescue mice from lethal polymicrobial sepsis. Here we developed a method of transcutaneous mechanical vagus nerve stimulation and then investigated whether this therapy can protect mice against sepsis lethality.

DESIGN

Prospective, randomized study.

SETTING

Institute-based research laboratory.

SUBJECTS

Male BALB/c mice.

INTERVENTIONS

Mice received lipopolysaccharide to induce lethal endotoxemia or underwent cecal ligation and puncture to induce polymicrobial sepsis. Mice were then randomized to receive electrical, transcutaneous, or sham vagus nerve stimulation and were followed for survival or euthanized at predetermined time points for cytokine analysis.

MEASUREMENTS AND MAIN RESULTS

Transcutaneous vagus nerve stimulation dose-dependently reduced systemic tumor necrosis factor levels during lethal endotoxemia. Treatment with transcutaneous vagus nerve stimulation inhibited HMGB1 levels and improved survival in mice with polymicrobial sepsis, even when administered 24 hrs after the onset of disease.

CONCLUSIONS

Transcutaneous vagus nerve stimulation is an efficacious treatment for mice with lethal endotoxemia or polymicrobial sepsis.

Chronic nicotine stimulation modulates the immune response of mucosal T cells to Th1-dominant pattern via nAChR by upregulation of Th1-specific transcriptional factor

Inflammatory bowel disease (IBD) consists of Crohn's disease (CD) and ulcerative colitis (UC). The etiology has not been clarified yet, but immune disorder is thought to be involved in the pathogenic physiology. Recently, general consensus has been reached that CD and UC are distinct, especially in respect of the immune response. Interestingly, smoking has diverse effects on CD, Th1-type enteritis, and on UC, Th2-type. However, the mechanisms remain obscure. Therefore, we hypothesized that nicotine altered the distinct immune responses in each form of IBD to affect their pathophysiology. In this study, we first demonstrated by RT-PCR analysis that human lamina propria T (LPT) cells had nicotinic acetylcholine receptor (nAChR), and express alpha7 nAChR subunit universally. In addition, the expression of T-bet mRNA in human LPT cells was significantly upregulated after the culture with 10(-7)M and 10(-5)M nicotine for 9 days, while chronic nicotine stimulation showed negligible effect on the expression of GATA-3 mRNA by real-time PCR. The effect of nicotine was inhibited by mecamylamine (MEC). These results suggested that nicotine could modulate the immune balance to Th1-dominant via nAChR in the intestine, to improve Th2-type enteritis. This may provide the experimental evidence for the fact that nicotine has a beneficial influence on UC, and exacerbates CD. Furthermore, it is of great interest that nicotine acts oppositely on CD and UC by modulation of the mucosal immune balance via the neurotransmitter receptor.

Central resistin induces hepatic insulin resistance via neuropeptide Y

Sensing of peripheral hormones and nutrients by the hypothalamus plays an important role in maintaining peripheral glucose homeostasis. The hormone resistin impairs the response to insulin in liver and other peripheral tissues. Here we demonstrate that in normal mice resistin delivered in the lateral cerebral ventricle increased endogenous glucose production during hyperinsulinemic-euglycemic clamp, consistent with induction of hepatic insulin resistance. In agreement, central resistin inhibited Akt phosphorylation and increased the expression of glucose-6-phosphatase, the enzyme regulating glucose output in the liver. Central resistin induced expression of proinflammatory cytokines as well as suppressor of cytokine signaling-3, a negative regulator of insulin action in liver. Central infusion of resistin was associated with neuronal activation in the arcuate, paraventricular and dorsomedial nuclei, and increased neuropeptide Y (NPY) expression in the hypothalamus. The effects of central resistin on glucose production as well as hepatic expression of proinflammatory cytokines were abrogated in mice lacking NPY. Pretreatment of wild-type mice with antagonists of the NPY Y1 receptor, but not the Y5 receptor, also prevented the effects of central resistin. Together, these results suggest that resistin action on NPY neurons is an important regulator of hepatic insulin sensitivity.

Cotinine-induced convergence of the cholinergic and PI3 kinase-dependent anti-inflammatory pathways in innate immune cells

Nicotine [(S)-3-(1-methyl-2-pyrrolidinyl)pyridine] is a major component of tobacco and a highly efficient acetylcholine receptor (nAChR) agonist that triggers the cholinergic anti-inflammatory pathway. We demonstrate that pre-treatment of monocytes with the stable nicotine catabolite, cotinine [(S)-1-methyl-5-(3-pyridinyl)-2-pyrrolidinone], dramatically alters the nature of the inflammatory response to Gram negative bacteria by abrogating the production of cytokines that are under the transcriptional control of the NF-kappaB system (TNF-alpha, IL-1beta, IL-6, IL-12/IL-23 p40) and shifting the response towards an IL-10-dominated anti-inflammatory profile. This anti-inflammatory phenomenon is initiated specifically by engagement of the monocytic alpha7 nAChR; and is PI3K/GSK-3beta-dependent; but NF-kappaB-independent. These mechanistic insights suggest an ability to exploit convergent, endogenous anti-inflammatory pathway(s) to either up-regulate or down-regulate the production of specific cytokine groups (pro- or anti-inflammatory cytokines) depending on the clinical necessity.

Gene expression profile in obesity and type 2 diabetes mellitus

Obesity is an important component of metabolic syndrome X and predisposes to the development of type 2 diabetes mellitus. The incidence of obesity, type 2 diabetes mellitus and metabolic syndrome X is increasing, and the cause(s) for this increasing incidence is not clear. Although genetics could play an important role in the higher prevalence of these diseases, it is not clear how genetic factors interact with environmental and dietary factors to increase their incidence. We performed gene expression profile in subjects with obesity and type 2 diabetes mellitus with and without family history of these diseases. It was noted that genes involved in carbohydrate, lipid and amino acid metabolism pathways, glycan of biosynthesis, metabolism of cofactors and vitamin pathways, ubiquitin mediated proteolysis, signal transduction pathways, neuroactive ligand-receptor interaction, nervous system pathways, neurodegenerative disorders pathways are upregulated in obesity compared to healthy subjects. In contrast genes involved in cell adhesion molecules, cytokine-cytokine receptor interaction, insulin signaling and immune system pathways are downregulated in obese. Genes involved in signal transduction, regulation of actin cytoskeleton, antigen processing and presentation, complement and coagulation cascades, axon guidance and neurodegenerative disorders pathways are upregulated in subjects with type 2 diabetes with family history of diabetes compared to those who are diabetic but with no family history. Genes involved in oxidative phosphorylation, immune, nervous system, and metabolic disorders pathways are upregulated in those with diabetes with family history of diabetes compared to those with diabetes but with no family history. In contrast, genes involved in lipid and amino acid pathways, ubiquitin mediated proteolysis, signal transduction, insulin signaling and PPAR signaling pathways are downregulated in subjects with diabetes with family history of diabetes. It was noted that genes involved in inflammatory pathway are differentially expressed both in obesity and type 2 diabetes. These results suggest that genes concerned with carbohydrate, lipid and amino acid metabolic pathways, neuronal function and inflammation play a significant role in the pathobiology of obesity and type 2 diabetes.

The effect of the cholinergic anti-inflammatory pathway on experimental colitis

Inflammatory bowel diseases (IBD) are characterized by proinflammatory cytokines, tissue damage and loss of neuron in inflamed mucosa, which implies the cholinergic anti-inflammatory pathway may be destroyed during the process of inflammatory response. In the study, we identified the effect of cholinergic agonist as anabaseine (AN) and nicotinic receptor antagonist as chlorisondamine diiodide (CHD) on trinitrobenzene sulfonic acid (TNBS)-induced colitis, to investigate the potential therapeutic effect of the cholinergic anti-inflammatory pathway on IBD. Experimental colitis was induced by TNBS at day 1, 10 mug AN or 1.5 mug CHD was injected i.p. to mouse right after the induction of colitis, and repeated on interval day till the mice were sacrificed at day 8. Colonic inflammation was examined by histological analysis, myeloperoxidase (MPO) activity, and the production of tumour necrosis factor (TNF)-alpha in tissue. Lamina propria mononuclear cells (LPMC) were isolated, and NF-kappaB activation was detected by western blot. The mice with colitis treated by AN showed less tissue damage, less MPO activity, less TNF-alpha production in colon, and inhibited NF-kappaB activation in LPMC, compared with those mice with colitis untreated, whereas the mice with colitis treated by CHD showed the worst tissue damage, the highest MPO activity, the highest TNF-alpha level, and enlarged NF-kappaB activation in LPMC. Agonist of the cholinergic anti-inflammatory pathway inhibits colonic inflammatory response by downregulating the production of TNF-alpha, and inhibiting NF-kappaB activation, which suggests that modulating the cholinergic anti-inflammatory pathway may be a new potential management for IBD.

Severe sepsis and septic shock: the role of gram-negative bacteremia

Abstract Although Gram-negative bacteria have often been implicated in the pathogenesis of severe sepsis and septic shock, how they trigger these often lethal syndromes is uncertain. In particular, the role played by blood-borne bacteria is controversial. This review considers two alternatives. In the first, circulating Gram-negative bacteria induce toxic reactions directly within the vasculature; in the second, the major inflammatory stimulus occurs in local extravascular sites of infection and circulating bacteria contribute little to inducing toxic responses. Evidence for each alternative is found in the literature. Bacteremia and severe sepsis are not so closely linked that the most striking cases can be a model for the rest. Intravascular and extravascular triggers may warrant different approaches to prevention and therapy.

Inflammation, genes and zinc in Alzheimer's disease

Alzheimer's disease (AD) is a heterogeneous and progressive neurodegenerative disease which in Western society mainly accounts for clinical dementia. AD has been linked to inflammation and metal biological pathway. Neuro-pathological hallmarks are senile plaques, resulting from the accumulation of several proteins and an inflammatory reaction around deposits of amyloid, a fibrillar protein, Abeta, product of cleavage of a much larger protein, the beta-amyloid precursor protein (APP) and neurofibrillary tangles. Amyloid deposition, due to the accumulation of Abeta peptide, is the main pathogenetic mechanism. Inflammation clearly occurs in pathologically vulnerable regions of AD and several inflammatory factors influencing AD development, i.e. environmental factors (pro-inflammatory phenotype) and/or genetic factors (pro-inflammatory genotype) have been described. At the biochemical level metals such as zinc are known to accelerate the aggregation of the amyloid peptide and play a role in the control of inflammatory responses. In particular, zinc availability may regulate mRNA cytokine expression, so influencing inflammatory network phenotypic expression.

The involvement of AMP-activated protein kinases in the anti-inflammatory effect of nicotine in vivo and in vitro

AMP-activated protein kinase (AMPK) is the downstream component of a kinase cascade that plays a pivotal role in energy homeostasis. AMPK has recently emerged as an attractive and novel target for inflammatory disorders. Thus, the aim of this study was to assess the role of AMPKalpha in the anti-inflammatory effect of nicotine in carrageenan-induced rat paw edema model and to evaluate the mechanism of nicotine-induced AMPKalpha phosphorylation in RAW 264.7 cells. The results indicate that nicotine alleviated paw edema and the activation of AMPKalpha involved in the anti-inflammatory effect of nicotine in vivo. In addition, nicotine was able to activate AMPKalpha phosphorylation in macrophages and this effect was mediated through nicotinic acetylcholine receptors. Furthermore, nicotine significantly induced the phosphorylation of Akt and the Ca(2+)/calmodulin-dependent protein kinase kinase (CaMKK) protein expression in macrophages. Wortmannin, a specific inhibitor of phosphotidylinositol 3-kinase (PI3K), suppressed nicotine-induced Akt and AMPKalpha phosphorylation. STO-609, a CaMKK inhibitor, not only inhibited the activation of AMPKalpha but also suppressed the phosphorylation of Akt induced by nicotine. In conclusion, both of CaMKK and PI3K/Akt pathways are involved in the nicotine-induced AMPKalpha phosphorylation in macrophages, and the interaction of CaMKK and Akt may exist. AMPKalpha is a novel and critical component of anti-inflammatory effect of nicotine.

Ghrelin inhibits sympathetic nervous activity in sepsis

Our previous studies have shown that norepinephrine (NE) upregulates proinflammatory cytokines by activating alpha(2)-adrenoceptor. Therefore, modulation of the sympathetic nervous system represents a novel treatment for sepsis. We have also shown that a novel stomach-derived peptide, ghrelin, is downregulated in sepsis and that its intravenous administration decreases proinflammatory cytokines and mitigates organ injury. However, it remains unknown whether ghrelin inhibits sympathetic activity through central ghrelin receptors [i.e., growth hormone secretagogue receptor 1a (GHSR-la)] in sepsis. To study this, sepsis was induced in male rats by cecal ligation and puncture (CLP). Ghrelin was administered through intravenous or intracerebroventricular injection 30 min before CLP. Our results showed that intravenous administration of ghrelin significantly reduced the elevated NE and TNF-alpha levels at 2 h after CLP. NE administration partially blocked the inhibitory effect of ghrelin on TNF-alpha in sepsis. GHSR-la inhibition by the administration of a GHSR-la antagonist, [d-Arg(1),d-Phe(5), d-Trp(7,9),Leu(11)]substance P, significantly increased both NE and TNF-alpha levels even in normal animals. Markedly elevated circulating levels of NE 2 h after CLP were also significantly decreased by intracerebroventricular administration of ghrelin. Ghrelin's inhibitory effect on NE release was completely blocked by intracerebroventricular injection of the GHSR-1a antagonist or a neuropeptide Y (NPY)/Y(1) receptor antagonist. However, ghrelin's downregulatory effect on TNF-alpha release was only partially diminished by these agents. Thus ghrelin has sympathoinhibitory properties that are mediated by central ghrelin receptors involving a NPY/Y1 receptor-dependent pathway. Ghrelin's inhibitory effect on TNF-alpha production in sepsis is partially because of its modulation of the overstimulated sympathetic nerve activation.

Mechanisms of CCK signaling from gut to brain

Following the observation that exogenous peripheral injection of CCK could inhibit food intake, the mechanisms by which CCK influences the gut-brain pathway have been the subject of intense study for nearly 30 years. Recently, it has become evident that the system is more complex and that the consequences of CCK's action on the gut-brain pathway are more far reaching than previously recognized. This review will examine the recent evidence showing the role of CCK and CCK1Rs in modulating expression of other receptors for orexigenic and anorexigenic regulatory peptides at the level of vagal afferent neurons. In addition, new evidence showing the importance of the action of CCK at the level of the vagus nerve in the regulation of food intake, body weight, and in activation of an anti-inflammatory pathway will be reviewed.

Alzheimer’s disease and genetics of inflammation: a pharmacogenomic vision

Inflammation plays a key role in Alzheimer disease, and dissecting the genetics of inflammation may provide an answer to the possible treatment. The next-generation therapy is based on a pharmacogenomics that will reconure new approaches to a drug used on definite people with specific dosage. The translation of pharmacogenomics into clinical practice will allow bold steps to be taken toward personalized medicine. In response to tissue injury elicited by trauma or infection, the inflammatory response sets in as a complex network of molecular and cellular interactions, directed to facilitate a return to physiological homeostasis and tissue repair. The role of an individual’s genetic background and predisposition for the extent of an inflammatory response is determined by variability of genes encoding endogenous mediators that constitute the pathways of inflammation. Due to its clinical relevance, in this review, the view on genetics of inflammation will be illustrated through a description of the genetic basis of a specific inflammatory disease, Alzheimer’s disease (AD). Several studies report a significantly different distribution, in patients and controls, of proinflammatory genes, alleles of which are under-represented in control subjects and over-represented in patients affected by AD. These studies will permit the detection of a risk profile that will potentially allow both the early identification of individuals susceptible to disease and the possible design or utilization of drug at the right dose for a desired effect – a pharmacogenomic approach for this disease.

Interleukin-18 and stress

Interleukin-18 (IL-18) is a pro-inflammatory cytokine believed to play a role in a variety of conditions and diseases including infections, autoimmunity, cancer, diabetes and atherosclerosis. IL-18 is also a possible contributor to the sickness syndrome by inducing anorexia and sleep. Originally recognized to be produced by cells of the immune system, IL-18 is also found in endocrine tissues, including the adrenal and the pituitary glands, and in the central nervous system where it is produced by microglial and ependymal cells as well as by neurons of the medial habenular nucleus. IL-18 is produced constitutively and its levels can increase during infection but also during stress in the absence of an exogenous stimulus. IL-18 levels are elevated by activation of the hypothalamic-pituitary-adrenal (HPA) axis in a tissue specific way via differential promoter and splicing usage, and may be down-regulated by the activation of the para-sympathetic system. This suggested the possibility that IL-18 may participate in the regulation of the HPA axis or that it may have a role in mediating the CNS dependent effects on the susceptibility to or the progression of diseases. This review summarizes the evidence linking stress and IL-18 and discusses the possible implication of the neuro-immuno-modulatory action of IL-18.

The neuroimmune basis of anti-inflammatory acupuncture

This review article presents the evidence that the antiinflammatory actions of acupuncture are mediated via the reflexive central inhibition of the innate immune system. Both laboratory and clinical evidence have recently shown the existence of a negative feedback loop between the autonomic nervous system and the innate immunity. There is also experimental evidence that the electrical stimulation of the vagus nerve inhibits macrophage activation and the production of TNF, IL-1beta , IL-6, IL-18, and other proinflammatory cytokines. It is therefore conceivable that along with hypnosis, meditation, prayer, guided imagery, biofeedback, and the placebo effect, the systemic anti-inflammatory actions of traditional and electro-acupuncture are directly or indirectly mediated by the efferent vagus nerve activation and inflammatory macrophage deactivation. In view of this common physiological mediation, assessing the clinical efficacy of a specific acupuncture regimen using conventional double-blind placebo-controlled trials inherently lacks objectivity due to (1) the uncertainty of ancient rules for needle placement, (2) the diffuse noxious inhibitory control triggered by control-needling at irrelevant points, (3) the possibility of a dose-response relationship between stimulation and effects, and (4) the possibility of inadequate blinding using an inert sham procedure. A more objective assessment of its efficacy could perhaps consist of measuring its effects on the surrogate markers of autonomic tone and inflammation. The use of acupuncture as an adjunct therapy to conventional medical treatment for a number of chronic inflammatory and autoimmune diseases seems plausible and should be validated by confirming its cholinergicity.

Challenges for modeling and interpreting the complex biology of severe injury and inflammation

Human injury is associated with inflammatory responses that are modulated by the acute and chronic activity of endogenous factors and exogenous interventions. A characteristic feature of chronic, severe inflammatory states is the diminished signal output variability of many organ systems, including innate immune responsiveness and endogenous neural and endocrine-mediated functions. The attenuation of signal/response variability and integration of feedback capacity may contribute to systemic and tissue-specific deterioration of function. Some well-intentioned therapies directed toward support of systemic and tissue functions may actually promote the loss of system(s) adaptability and contribute to adverse outcomes in severely stressed patients. In vivo and in silico models of stress, injury, and infection have yet to fully define the influences of ongoing stressful stimulae as well as genetic variation and epigenetic factors in the context of an evolving inflammatory state. Experimental and human models incorporating variable, antecedent stress(es) and altered neuroendocrine rhythms might approximate the altered adaptability in immune and organ function responses. Such models may also provide insights into the salient mechanisms of risk and outcome more precisely than do the constrained study conditions of current animal or human models of systemic inflammation.

Tiotropium suppresses acetylcholine-induced release of chemotactic mediators in vitro

The driving force in the progression of COPD is the development of exacerbations which are mostly the result of excessive inflammation. Bronchodilatators play an important role in the treatment of COPD. The reported reduction in exacerbation rates in COPD is due to the inhibition of vagal-mediated bronchoconstriction and mucus secretion. However, recent studies have highlighted the existence of muscarinic receptors on inflammatory cells and we have explored the possibility that tiotropium bromide might also inhibit neutrophil migration. We analysed the influence of tiotropium on the release of neutrophil chemotactic activity in response to acetylcholine (ACh) and the expression of muscarinic receptors on human alveolar macrophages (AM), A549 cells, MonoMac6 cells, and human lung fibroblasts. We found significant levels of all muscarinic receptor subtypes on all analysed cells except the fibroblasts. Fibroblasts expressed predominantly M2, receptors and did not release chemotactic activity. AM, A549 cells, and MonoMac6 cells released chemotactic active mediators after incubation with ACh. The secretion could be suppressed by more than 70% after coincubation with tiotropium. Tiotropium alone did not influence the granulocyte migration. Most of the chemotactic activity could be attributed to leukotriene B4 (LTB4). The release of interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1) was not induced by ACh. From this, we suggest that the suppression of the Ach-mediated release of chemotactic substances like LTB4 modulates the inflammatory reaction. This may contribute to the decreased rate of exacerbations in COPD, which was observed in clinical trials.

Stimulated production of proinflammatory cytokines covaries inversely with heart rate variability

OBJECTIVE

To examine whether high-frequency heart rate variability, an indirect measure of parasympathetic (vagal) control over variations in heart rate, is associated with immune reactivity to an in vitro inflammatory challenge. Convergent evidence from the animal literature shows that the autonomic nervous system plays a key role in regulating the magnitude of immune responses to inflammatory stimuli. Signaling by the parasympathetic system inhibits the production of proinflammatory cytokines by activated monocytes/macrophages and thus decreases local and systemic inflammation. As yet, no direct human evidence links parasympathetic activity to inflammatory competence.

METHODS

We examined the relationship of variations in heart rate, recorded during paced respiration, to lipopolysaccharide-induced production of the inflammatory cytokines interleukin (IL)-1beta, IL-6, tumor necrosis factor (TNF)-alpha, and IL-10 among a community sample of 183 healthy adults (mean age = 45 years; 59% male; 92% White, 7% African-American).

RESULTS

Consistent with animal findings, higher derived estimates of vagal activity measured during paced respiration were associated with lower production of the proinflammatory cytokines TNF-alpha and IL-6 (r = -.18 to -.30), but were not related to production of the anti-inflammatory cytokine IL-10. These associations persisted after controlling for demographic and health characteristics, including age, gender, race, years of education, smoking, hypertension, and white blood cell count.

CONCLUSIONS

These data provide initial human evidence that vagal activity is inversely related to inflammatory competence, raising the possibility that vagal regulation of immune reactivity may represent a pathway linking psychosocial factors to risk for inflammatory disease.

The survival time post-cecal ligation and puncture in sinoaortic denervated rats

Arterial baroreflex (ABR) function is an important determinant factor in prognosis of many cardiovascular diseases. The present work was designed to study the relationship between ABR function and the survival time of septic shock in a cecal ligation and puncture (CLP) rat model. The dysfunction of ABR was introduced by sinoaortic denervation (SAD). It was found that the survival time after CLP was significantly reduced in SAD rats compared with sham-operated rats (12.7 +/- 2.92 hours versus 15.0 +/- 4.01 hours; P < 0.05). Furthermore, significant differences were also seen when the results were expressed by Kaplan-Meier survival curves. Compared with the baseline values, both noradrenaline and adrenaline significantly increased in both SAD and Sham groups after CLP, but we found the baseline of noradrenaline was significantly elevated in SAD rats. In addition, the TNF-alpha, noradrenaline, and adrenaline levels of the SAD group were significantly higher than those of the Sham group at 5 hours post-CLP. In conclusion, the present work demonstrates that ABR function was related to the survival time in CLP-induced lethal shock model. The loss of inhibition in the sympathetic activity and in the release of some inflammatory cytokines during CLP-induced septic shock related to baroreflex and/or chemoreflex dysfunction may be the mechanisms involved in the poorer prognosis in septic shock.

Association between short term and long term communication in pathological autonomic control

Autonomic Information Flow (AIF) reflects the time scale dependence of autonomic communications such as vagal, sympathetic, and slower rhythms and their complex interplay. We investigated the hypothesis that pathologically disturbed short term control is associated with simplified complex long term control. This particular characteristic of altered autonomic communication was evaluated in different medical patient groups. Holter recordings were assessed in patients with multiple organ dysfunction (MODS) (26 survivors, 10 non-survivors); with heart failure (14 low risk-without history of aborted cardiac arrest (CA), 13 high risk--with history of CA); with idiopathic dilated cardiomyopathy (IDC) (26 low risk, 11 high risk of CA), after myocardial infarction (MI) (1221 low risk--survivors, 55 high risk--non-survivors); after abdominal aorta surgery (AAS, 32 length of stay in hospital LOS>7 days, 62 LOS < or =7 days). AIF of short and long time scales was investigated. We found a fundamental association of increased short term randomness and decreased long term randomness due to pathology. Concerning risk, high risk patients were characterized by increased short term complexity and decreased long term complexity in all patients groups with the exception of the IDC patients. We conclude that different time scales of AIF represent specific pathophysiological aspects of altered autonomic communication and control. The association of altered short term control with simplified long term behavior might be a pathophysiologically relevant compensation mechanism in the case of a disturbed fastest actuator. This knowledge might be useful for the development of comprehensive therapeutic strategies besides the predictive implications.

Neostigmine and pilocarpine attenuated tumour necrosis factor α expression and cardiac hypertrophy in the heart with pressure overload

The inflammatory cytokine tumour necrosis factor alpha (TNF alpha) is known to be a major factor contributing to cardiac remodelling and dysfunction. Parasympathetic nervous system cholinergic function can inhibit TNF alpha expression during systemic infection. In the present study, we tested the effects of a cholinesterase inhibitor, neostigmine, and a muscarinic cholinergic agonist, pilocarpine, on cardiac hypertrophy and TNF alpha levels during pressure overload. Rats with transverse aortic constriction exhibited elevated TNF alpha protein levels in the heart, increased heart weight to body weight ratios (an index of cardiac hypertrophy) and decreased left ventricular diastolic function. Two weeks of infusion with neostigmine (6 microg kg(-1) day(-1)) or pilocarpine (0.3 mg kg(-1) day(-1)) significantly reduced cardiac hypertrophy, reduced TNF alpha levels and elevated interleukin-10 levels in heart tissues, and improved ventricular function in rats with transverse aortic constriction. Neither of these treatments significantly changed ventricular pressure load. Furthermore, in primary cultured neonatal cardiac cells, treatment with pilocarpine attenuated adrenergic agonist phenylephrine-induced increased TNF alpha expression and [3H]leucine (a marker of protein synthesis) incorporation in the cells. Collectively, both cholinergic agents decreased TNF alpha levels and attenuated cardiac hypertrophy. Since both agents potentially enhanced cholinergic function, the anti-inflammatory action may be involved in the cardioprotective effect of the treatments with these agents.

Association of decreased variation of R-R interval and elevated serum C-reactive protein level in a general population in Japan

Several studies have suggested that an increased high sensitivity C-reactive protein (hsCRP) level is a strong independent predictor of increased risk for atherosclerotic cardiovascular mortality and morbidity. Reduced heart rate variability (HRV) has also been reported to predict cardiovascular events such as sudden death and myocardial infarction in apparently healthy subjects. The aim of this cross-sectional study was to test the possible correlation between variation of the R-R interval as one of the markers of HRV and serum hsCRP levels in a general population in Japan. Resting, supine, 2-minute, beat-to-beat heart rate data were collected in 823 randomly selected participants enrolled in our cohort study. The coefficient of variation of the R-R interval (CVrr) was obtained as a parameter of HRV. To determine which factors predict the presence of low CVrr (below the 5 percentile) in this group, we performed a multivariate logistic regression analysis using cardiovascular risk factors and an elevated hsCRP level as independent variables. The lowest CVrr group showed significantly higher hsCRP levels compared to those of other quartiles (P < 0.01). After adjustment for confounding factors such as age, heart rate, obesity, hypercholesterolemia, and hypertension by multivariate logistic analysis, an elevated hsCRP level (OR = 3.11, 95%CI; 1.27-7.60: P < 0.02) was a significant independent predictor of low CVrr. The results of the present study indicate that an increased serum hsCRP level is significantly associated with reduced CVrr in this general population. It is conceivable that the parasympathetic nerve withdrawal and inflammation could interact with each other, resulting in the progression of atherosclerotic cardiovascular disease.

Activation of the cholinergic anti-inflammatory pathway ameliorates postoperative ileus in mice

BACKGROUND & AIMS

We previously showed that intestinal inflammation is reduced by electrical stimulation of the efferent vagus nerve, which prevents postoperative ileus in mice. We propose that this cholinergic anti-inflammatory pathway is mediated via alpha7 nicotinic acetylcholine receptors expressed on macrophages. The aim of this study was to evaluate pharmacologic activation of the cholinergic anti-inflammatory pathway in a mouse model for postoperative ileus using the alpha7 nicotinic acetylcholine receptor-agonist AR-R17779.

METHODS

Mice were pretreated with vehicle, nicotine, or AR-R17779 20 minutes before a laparotomy (L) or intestinal manipulation (IM). Twenty-four hours thereafter gastric emptying was determined using scintigraphy and intestinal muscle inflammation was quantified. Nuclear factor-kappaB transcriptional activity and cytokine production was assayed in peritoneal macrophages.

RESULTS

Twenty-four hours after surgery IM led to a delayed gastric emptying compared with L (gastric retention: L(saline) 14% +/- 4% vs IM(saline) 38% +/- 10%, P = .04). Pretreatment with AR-R17779 prevented delayed gastric emptying (IM(AR-R17779) 15% +/- 4%, P = .03). IM elicited inflammatory cell recruitment (L(saline) 50 +/- 8 vs IM(saline) 434 +/- 71 cells/mm(2), P = .001) which was reduced by AR-R17779 pretreatment (IM(AR-R17779) 231 +/- 32 cells/mm(2), P = .04). An equimolar dose of nicotine was not tolerated. Subdiaphragmal vagotomy did not affect the anti-inflammatory properties of AR-R17779. In peritoneal macrophages, both nicotinic agonists reduced nuclear factor kappaB transcriptional activity and proinflammatory cytokine production, with nicotine being more effective than AR-R17779.

CONCLUSIONS

AR-R17779 treatment potently prevents postoperative ileus, whereas toxicity limits nicotine administration to ineffective doses. Our data further imply that nicotinic inhibition of macrophage activation may involve other receptors in addition to alpha7 nicotinic acetylcholine receptor.

The protective effect of the vagus nerve in a murine model of chronic relapsing colitis

The vagus nerve inhibits the response to systemic administration of endotoxin, and we have recently extended this observation to show that the vagus attenuates acute experimental colitis in mice. The purpose of the present study was to determine whether there is a tonic counterinflammatory influence of the vagus on colitis maintained over several weeks. We assessed disease activity index, macroscopic and histological damage, myeloperoxidase (MPO) activity, and Th1 and Th2 cytokine profiles in chronic colitis induced by administration of dextran sodium sulfate (DSS) in drinking water for three cycles during 5 days with 11 days of rest between each cycle (DSS 3, 2, 2%) in healthy and vagotomized C57BL/6 mice and in mice deficient in macrophage-colony stimulating factor (M-CSF). A pyloroplasty was performed in vagotomized mice. Vagotomy accelerated the onset and the severity of inflammation during the first and second but not the third cycle. Although macroscopic scores were not significantly changed, histological scores as well as MPO activity and colonic tissue levels of IL-1alpha, TNF-alpha, IFN-gamma, and IL-18 but not IL-4 were significantly increased in vagotomized mice compared with sham-operated mice that received DSS. In control mice (without colitis), vagotomy per se did not affect any inflammatory marker. Vagotomy had no effect on the colitis in M-CSF-derived macrophage-deficient mice. These results indicate that the vagus protects against acute relapses on a background of chronic inflammation. Identification of the molecular mechanisms underlying the protective role of parasympathetic nerves opens a new therapeutic avenue for the treatment of acute relapses of chronic inflammatory bowel disease.

Pain in chronic pancreatitis: a salutogenic mechanism or a maladaptive brain response?

Pain in chronic pancreatitis is frequently refractory to medical and even surgical treatment. This refractoriness leads us to believe that a pancreas-independent, brain-mediated mechanism must be responsible. If so, several scenarios are worth considering. First, chronic pain could be the consequence of undesirable neuroplastic changes, by which pathology becomes established and causes disability. Alternatively, pain may be linked to the salutogenic (from salutogenesis, the Latin word for health and well-being) central nervous system response (we defined 'salutogenic response' as the specific modulation of the immune system induced by brain activity changes) to promote healing of the injured viscera. If so, chronic pain could index the ongoing nervous system attempt to promote healing. In this review, we discuss (1) the mechanisms of pain in chronic pancreatitis; (2) potential brain-related salutogenic mechanisms, and (3) the potential relationship of these two factors to the disease status. Furthermore, we consider these aspects in light of a new approach to treat visceral pain: transcranial magnetic stimulation, a noninvasive method of brain stimulation.

Phagocyte-derived catecholamines enhance acute inflammatory injury

It is becoming increasingly clear that the autonomic nervous system and the immune system demonstrate cross-talk during inflammation by means of sympathetic and parasympathetic pathways. We investigated whether phagocytes are capable of de novo production of catecholamines, suggesting an autocrine/paracrine self-regulatory mechanism by catecholamines during inflammation, as has been described for lymphocytes. Here we show that exposure of phagocytes to lipopolysaccharide led to a release of catecholamines and an induction of catecholamine-generating and degrading enzymes, indicating the presence of the complete intracellular machinery for the generation, release and inactivation of catecholamines. To assess the importance of these findings in vivo, we chose two models of acute lung injury. Blockade of alpha2-adrenoreceptors or catecholamine-generating enzymes greatly suppressed lung inflammation, whereas the opposite was the case either for an alpha2-adrenoreceptor agonist or for inhibition of catecholamine-degrading enzymes. We were able to exclude T cells or sympathetic nerve endings as sources of the injury-modulating catecholamines. Our studies identify phagocytes as a new source of catecholamines, which enhance the inflammatory response.