Role of neurogenic inflammation in the pathogenesis of alopecia areata

Alopecia areata refers to an autoimmune illness indicated by persistent inflammation. The key requirement for alopecia areata occurrence is the disruption of immune-privileged regions within the hair follicles. Recent research has indicated that neuropeptides play a role in the damage to hair follicles by triggering neurogenic inflammation, stimulating mast cells ambient the follicles, and promoting apoptotic processes in keratinocytes. However, the exact pathogenesis of alopecia areata requires further investigation. Recently, there has been an increasing focus on understanding the mechanisms of immune diseases resulting from the interplay between the nervous and the immune system. Neurogenic inflammation due to neuroimmune disorders of the skin system may disrupt the inflammatory microenvironment of the hair follicle, which plays a crucial part in the progression of alopecia areata.

Neurogenic Inflammation in the Context of Endometriosis-What Do We Know?

Endometriosis (EM) is an estrogen-dependent disease characterized by the presence of epithelial, stromal, and smooth muscle cells outside the uterine cavity. It is a chronic and debilitating condition affecting ~10% of women. EM is characterized by infertility and pain, such as dysmenorrhea, chronic pelvic pain, dyspareunia, dysuria, and dyschezia. Although EM was first described in 1860, its aetiology and pathogenesis remain uncertain. Recent evidence demonstrates that the peripheral nervous system plays an important role in the pathophysiology of this disease. Sensory nerves, which surround and innervate endometriotic lesions, not only drive the chronic and debilitating pain associated with EM but also contribute to a growth phenotype by secreting neurotrophic factors and interacting with surrounding immune cells. Here we review the role that peripheral nerves play in driving and maintaining endometriotic lesions. A better understanding of the role of this system, as well as its interactions with immune cells, will unearth novel disease-relevant pathways and targets, providing new therapeutics and better-tailored treatment options.

Chrysomycin A Attenuates Neuroinflammation by Down-Regulating NLRP3/Cleaved Caspase-1 Signaling Pathway in LPS-Stimulated Mice and BV2 Cells

Chrysomycin A (Chr-A), an antibiotic chrysomycin, was discovered in 1955 and is used to treat cancer and tuberculosis. In the present study, the anti-neuroinflammatory effects and possible mechanism of Chr-A in BALB/c mice and in BV2 microglia cells stimulated by lipopolysaccharide (LPS) were investigated. Firstly, the cortex tissues of mice were analyzed by RNA-seq transcriptome to identify differentially expressed genes (DEGs) regulated by Chr-A in LPS-stimulated mice. Inflammatory cytokines and inflammatory proteins were detected by enzyme-linked immunosorbent assay and Western blot. In RNAseq detection, 639 differential up-regulated genes between the control group and LPS model group and 113 differential down-regulated genes between the LPS model group and Chr-A treatment group were found, and 70 overlapping genes were identified as key genes for Chr-A against neuroinflammation. Subsequent GO biological process enrichment analysis showed that the anti-neuroinflammatory effect of Chr-A might be related to the response to cytokine, cellular response to cytokine stimulus, and regulation of immune system process. The significant signaling pathways of KEGG enrichment analysis were mainly involved in TNF signaling pathway, cytokine-cytokine receptor interaction, NF-κB signaling pathway, IL-17 signaling pathway and NOD-like receptor signaling pathway. Our results of in vivo or in vitro experiments showed that the levels of pro-inflammatory factors including NO, IL-6, IL-1β, IL-17, TNF-α, MCP-1, CXCL12, GM-CSF and COX2 in the LPS-stimulated group were higher than those in the control group, while Chr-A reversed those conditions. Furthermore, the Western blot analysis showed that its anti-neuroinflammation appeared to be related to the down-regulation of NLRP3/cleaved caspase-1 signaling pathway. The current findings provide new insights into the activity and molecular mechanisms of Chr-A for the treatment of neuroinflammation.

Metabolic Defects Caused by High-Fat Diet Modify Disease Risk through Inflammatory and Amyloidogenic Pathways in a Mouse Model of Alzheimer's Disease

High-fat diet (HFD) has been shown to accelerate Alzheimer’s disease (AD) pathology, but the exact molecular and cellular mechanisms remain incompletely understood. Moreover, it is unknown whether AD mice are more susceptible to HFD-induced metabolic dysfunctions. To address these questions, we used 5xFAD mice as an Alzheimer’s disease model to study the physiological and molecular underpinning between HFD-induced metabolic defects and AD pathology. We systematically profiled the metabolic parameters, the gut microbiome composition, and hippocampal gene expression in 5xFAD and wild type (WT) mice fed normal chow diet and HFD. HFD feeding impaired energy metabolism in male 5xFAD mice, leading to increased locomotor activity, energy expenditure, and food intake. 5xFAD mice on HFD had elevated circulating lipids and worsened glucose intolerance. HFD caused profound changes in gut microbiome compositions, though no difference between genotype was detected. We measured hippocampal mRNAs related to AD neuropathology and neuroinflammation and showed that HFD elevated the expression of apoptotic, microglial, and amyloidogenic genes in 5xFAD mice. Pathway analysis revealed that differentially regulated genes were involved in insulin signaling, cytokine signaling, cellular stress, and neurotransmission. Collectively, our results showed that 5xFAD mice were more susceptible to HFD-induced metabolic dysregulation and suggest that targeting metabolic dysfunctions can ameliorate AD symptoms via effects on insulin signaling and neuroinflammation in the hippocampus.

Pathogenesis of pelvic pain syndrome associated with endometriosis in patients resistant to surgical treatment

AIM

Endometriosis is one of the most common gynecological diseases diagnosed in almost 70% of patients with chronic pelvic pain (CPP). However, a quarter of women with pelvic pain is diagnosed with external genital endometriosis (EGE) during laparoscopy. A special group is represented by patients with PP that did not stop after the removal of endometrial foci. The mechanisms of the pathogenesis of the formation of pain syndrome are not completely explored yet. According to several authors, a significant role in the pathogenesis of pelvic pain recurrence after surgical treatment of EGE is played by active neuroangiogenesis, both in ectopic and eutopic endometrium. The aim of the study was to expand the understanding of the pathogenesis of pelvic pain that did not stop (recurrence) after surgical treatment of external genital endometriosis.

MATERIAL AND METHODS

The study involved 2 stages. At the first stage (algological), data from B&B, NRS and VRS algological questionnaires, which were completed by patients with recurrent PP after surgical treatment of EGE, were analyzed (n = 130, aged 18-45 years old, average age 32.5 ± 7.6 years). All women were operated on for EGE no later than 3-6 months after assessing the patients by the algological questionnaires; they did not receive drug therapy after surgical treatment and sought medical attention for recurrent pelvic pain. Materials for the study of the endometrium were obtained by the pipelle biopsymethod. The control group was formed from a number of women with EGE without PP, who applied for surgical treatment of infertility (n = 30).

RESULTS

The results of the study have shown that the basis of pathogenesis of pelvic pain recurrence in patients who did not receive medical therapy after surgical treatment of EGE is the activation of neuro-angiogenesis processes and reduction of apoptosis. The results show a statistically significant 1.6 times increasing expression of NGF in eutopic endometrium (57.9 ± 2.5 vs 35.3 ± 2.1% of patients with the silent form of the gene and its receptor NTRK1 1.8 times (2.78 ± 0.25 versus 1.56 ± 0.21.e. respectively). Conclusion: The pathogenesis of pelvic pain in patients who did not receive medical therapy after surgical treatment of endometriosis compared to no pain form of the disease is the activation of the processes of neurogenesis in the eutopic endometrium.

Endocannabinoid regulation of amyloid-induced neuroinflammation

The modulation of endocannabinoid (EC) levels and the activation of cannabinoid receptors are seen as promising therapeutic strategies in a variety of diseases, including Alzheimer's disease (AD). We aimed to evaluate the effect of the pharmacologic and genetic inhibition of anandamide-degrading enzyme in a mouse model of AD (5xFAD). Pharmacologic inhibition of the fatty acid amide hydrolase (FAAH) had little impact on the expression of key enzymes and cytokines and also on the cognitive impairment, plaque deposition, and gliosis in 5xFAD mice. CB1 blockade exacerbated inflammation in this transgenic mouse model of AD. The genetic inactivation of FAAH led to increases in the expression of inflammatory cytokines. At the same time, FAAH-null 5xFAD mice exhibited a behavioral improvement in spatial memory that was independent of the level of anxiety and was not CB1 mediated. Finally, mice lacking FAAH showed diminished soluble amyloid levels, neuritic plaques, and gliosis. These data reinforce the notion of a role for the EC system in neuroinflammation and open new perspectives on the relevance of modulating EC levels in the inflamed brain.

How can sensitive dentine become hypersensitive and can it be reversed?

This paper reviews a number of studies in oral biology and endodontics that deal with the reactivity of the pulpo-dentine complex in response to mechanical and immunological stimuli. It can be hypothesized that these reactions could also apply to changes in dentine sensitivity following periodontal procedures. Some of these changes involve neurogenic inflammation of the pulp under exposed open tubules; this increases the rate of outward fluid flow through the tubules, making the overlying exposed dentine more sensitive. Other changes may be due to inflammation-related nerve sprouting of pulpal nerves, which can lead to innervation of more tubules than normal. Changes may also involve upregulation of new, more sensitive ion channels in the membranes of these nerves. The goal of the paper is to increase awareness of the complex issues involved in dentine sensitivity, so that future investigators may develop agents or techniques to stimulate mechanisms that mitigate dentine sensitivity, or to block mechanisms that aggravate the condition, for therapeutic effect.

Women of valor: post-traumatic stress disorder in the dental practice

Dental professionals can intervene in head, neck and facial pain found in female patients who suffer from post-traumatic stress disorder (PTSD). There are three theories for why women are predisposed to pain: hormonal differences, nervous system rewiring and sympathetic issues. This article includes case studies of three patients who are representative of these theories. A rapid, nonintrusive intervention will also be described.

The effect of sensory nerve stimulation on sensory nerve function in people with peripheral neuropathy associated with diabetes

OBJECTIVE

To assess the effect of sensory nerve stimulation in older people with peripheral neuropathy associated with diabetes (DPN).

MATERIALS AND METHODS

A randomized, placebo controlled, double blind trial was used to assess the effect of 12 weeks of low frequency sensory nerve stimulation (LF-SNS) in the lower limb [International Patent Application No. PCT/AU2004/001079: 'nerve function and tissue healing' (Z. Khalil)]. Response to capsaicin, basal microvascular blood flow, electric cutaneous threshold and oxygen tension were assessed pre- and post-treatment and between limbs.

PARTICIPANTS

People 55 years of age or older diagnosed with DPN: 35 active and 31 placebo participants.

RESULTS

Between groups comparisons: no significant differences occurred between stimulation groups. Within subject comparisons: in the active LF-SNS group, comparing stimulated to contralateral legs, there were significant increases in size of capsaicin flare [t(1,33)=3.65, p<0.05] and capillary blood flow [t(1,34)=-0.33, p<0.05]. There was a trend to improvement in time to initial flare response [t(1,34)=-1.86, p=0.07]. No changes were evident in the placebo group. RESPONDER ANALYSES: In a group of 'responders', the time to initial flare response (p<0.05, r=0.64), size of capsaicin flare (p<0.05 r=1.0) and microvascular blood flow (p<0.05, r=0.60) improved significantly after LF-SNS.

CONCLUSIONS

The observed data suggest that LF-SNS improves nerve function in a subset of people with DPN. Targeting toward probably 'responders' may deliver the greatest benefit from short-term therapy. Testing optimal application in others seems warranted.

[A guinea pig model of respiratory syncytial virus infection for cough and its neurogenic inflammatory mechanism]

OBJECTIVE

To establish a guinea pig model of acute and postinfectious cough caused by respiratory syncytial virus (RSV) infection and investigate the role of neurogenic inflammation in its pathogenesis.

METHODS

Fifty guinea pigs were randomly divided into control group and four groups of Days 6, 12, 28 and 42 after RSV inoculation (n = 10 each). The RSV suspension was inoculated by intranasal instillation. Buxco system was used to assess the cough reflex sensitivity (CRS) to inhaled capsaicin. Airway inflammation was determined by bronchoalveolar lavage fluid (BALF) cytology and lung histopathology. RSV antigen and nucleic acid were detected by immunofluorescence and real-time fluorescence quantitative PCR (polymerase chain reaction). After modeling, the content of substance P in homogenate of lung tissue was detected by ELISA (enzyme-linked immunosorbent assay) kit. The level of neurokinins receptor 1 (NK1) mRNA in lung tissue was detected by real-time PCR. The expression of substance P protein in lung tissue was detected by immunohistochemistry. The correlation analyses between CRS and the levels of substance P and NK1 mRNA were performed respectively.

RESULTS

The viral antigen expression could be found in lung tissue of RSV infected guinea pigs. The concentration of RSV RNA content showed a gradually decreasing trend with infection time until 42 days at very low titers. The CRS values were (8.0 ± 1.2), (8.7 ± 2.0), (7.6 ± 1.4) and (6.7 ± 1.2) cough counts at Days 6, 12, 28 and 42 respectively. Compared with (2.5 ± 0.5) cough counts of control group, the CRS to capsaicin increased significantly in all animals with PIV3 inoculation (all P < 0.05) and peaked at Day 12 (P < 0.01). BALF cytology and lung tissue pathology showed airway inflammation during the acute stage of infection without pneumonia. All the contents of substance P in lung tissue homogenates increased markedly in infected groups. The immunohistochemical results of substance P in lung tissue of infected groups showed a distinct brown-yellow positive expression. In addition to Group Day 6, the NK1 mRNA contents of lung tissue in all other infection groups became elevated significantly. The correlation analysis showed a positive correlation between CRS and the levels of substance P and NK1 mRNA (all P < 0.05).

CONCLUSION

A guinea pig model for cough of RSV infection has been successfully established. The elevated releases of substance P and its receptor may cause neurogenic inflammation. And airway neurogenic inflammation may play a decisive role in the heightened CRS and postinfectious cough induced by RSV.

Neutral endopeptidase inhibition enhances substance P mediated inflammation due to hypomagnesemia

During dietary deficiency of magnesium neurogenic inflammation is mediated, primarily, by elevated levels of substance P (SP). The enzyme most specific for degrading this neuropeptide is neutral endopeptidase (NEP). In recent studies we found that pharmacological inhibition of NEP by phosphoramidon resulted in elevated plasma levels of SP and greater oxidative stress. We also observed that hypomagnesemia reduced cardiac and intestinal expression of NEP. In these magnesium-deficient rats increased intestinal permeability and impaired cardiac contractility occurred. In our colony of genetically-engineered NEP knockout mice that have reduced ability to degrade SP, we found increased oxidative stress that was prevented by SP (neurokinin-1) receptor blockade. Thus, we submit that inhibition of NEP by pharmacological, genetic and dietary approaches (magnesium restriction), causes greater neurogenic inflammation that may result in increased intestinal and cardiac dysfunction.

Neurogenic inflammation and cardiac dysfunction due to hypomagnesemia

Hypomagnesemia continues to be a significant clinical disorder that is present in patients with diabetes mellitus, alcoholism, and treatment with magnesuric drugs (diuretics, cancer chemotherapy agents, etc.). To determine the role of magnesium in cardiovascular pathophysiology, we have used dietary restriction of this cation in animal models. This review highlights some key observations that helped formulate the hypothesis that release of substance P (SP) during experimental dietary Mg deficiency (MgD) may initiate a cascade of deleterious inflammatory, oxidative, and nitrosative events, which ultimately promote cardiomyopathy, in situ cardiac dysfunction, and myocardial intolerance to secondary stresses. SP acts primarily through neurokinin-1 receptors of inflammatory and endothelial cells, and may induce production of reactive oxygen and nitrogen species (superoxide anion, NO*, peroxynitrite, hydroxyl radical), leading to enhanced consumption of tissue antioxidants; stimulate release of inflammatory mediators; promote tissue adhesion molecule expression; and enhance inflammatory cell tissue infiltration and cardiovascular lesion formation. These SP-mediated events may predispose the heart to injury if faced with subsequent oxidative stressors (ischemia/reperfusion, certain drugs) or facilitate development of in situ cardiac dysfunction, especially with prolonged dietary Mg restriction. Significant protection against most of these MgD-mediated events has been observed with interventions that modulate neuronal SP release or its bioactivity, and with several antioxidants (vitamin E, probucol, epicaptopril, d-propranolol). In view of the clinical prevalence of hypomagnesemia, new treatments, beyond magnesium repletion, may be needed to diminish deleterious neurogenic and prooxidative components described in this article.

Neurogenic inflammation of the upper airway mucosa

Chronic inflammation of the upper airway mucosa is most likely caused by multiple factors, but is frequently associated with local neurogenic inflammation. This phenomenon can be induced by the inhalation of exogenous particles and chemicals present in our environment, as well as irritants produced endogenously. These irritants, i.e. histamine, H+ or bradykinin, can stimulate the abundant afferent sensory nerves endings, epithelial and neuroendocrine cells present in the upper airways mucosa. These structures can interact with our immune and neural cells by producing pro-inflammatory neuropeptides, cytokines, chemokines and neurotrophins. This short review summarizes some of our current knowledge with regard to the role of airborne chemical stimuli and their possible implications in the development of chronic inflammation of the upper airways mucosa.

The pillar pain in the carpal tunnel's surgery. Neurogenic inflammation? A new therapeutic approach with local anaesthetic

AIM

After the surgical decompression of the transverse carpal ligament as treatment of the tunnel carpal syndrome, pillar pain manifestation is possible. This is a painful and temporary invaliding syndrome with unknown aetiology. Aim of the study is to demonstrate that pillar pain is based on autonomic irritation that disappears with simple infiltration of local anaesthetic (LA), or rather by neuromodulation.

METHODS

Eighty-four patients were enrolled for this study and underwent an open release technique surgery. They were then asked for regular postoperative follow-ups.

RESULTS

Thirty-two out of 84 patients (38%) developed pillar pain. Accordingly, injection of LA as pain treatment has since been studied and results compared with the conventional protocol for this painful syndrome.

CONCLUSION

Even if the number of the patients considered is not great, there is evidence of a decrement of pillar pain by means of LA injections. Excellent functional outcomes and satisfaction were achieved using LA infiltrations for pillar pain after carpal tunnel decompression. The minimally invasive technique offers a quick, easy, effective, and inexpensive method useful to minimize and cure in a few days the pillar pain.

The Mast Cell in Interstitial Cystitis: Role in Pathophysiology and Pathogenesis

Current evidence from clinical and laboratory studies confirms that mast cells play a central role in the pathogenesis and pathophysiology of interstitial cystitis (IC). In this article, we focus on the role of the mast cell in IC and examine the ways in which mast cells and other pathophysiologic mechanisms are interrelated in this disease. Identifying the patients with IC who have mast cell proliferation and activation will enable us to address this aspect of disease pathophysiology in these individuals with targeted pharmacotherapy to inhibit mast cell activation and mediator release.

The role of Transient Receptor Potential Vanilloid 1 (TRPV1) channels in pancreatitis

Premature activation of digestive enzymes within the pancreas which leads to autodigestion of the gland is an early step in the pathogenesis of pancreatitis. Pancreatic injury is followed by other manifestations of inflammation including plasma extravasation, edema, and neutrophil infiltration which constitute the features of pancreatitis. Recent studies indicate that neural innervation of the pancreas may play an important role in the initiation and maintenance of the inflammatory response to injury. The pancreas is innervated by vagal, sympathetic and parasympathetic neurons, as well as sensory neurons. Activation of pancreatic primary sensory neurons causes the release of inflammatory neuropeptides both in the spinal cord to signal pain and in the pancreas itself where they produce plasma extravasation and neutrophil infiltration. Recent studies indicate that primary sensory neurons of the pancreas express transient receptor potential V1 (TRPV1) channels whose activation induces pancreatic inflammation. Moreover, blockade of these TRP channels significantly ameliorates experimental pancreatitis. This review describes our current understanding of the role of TRPV1 channels in pancreatitis and illustrates how this mechanism might be used to direct future treatments of pancreatic diseases.

Apolipoprotein E-derived peptides reduce CNS inflammation: implications for therapy of neurological disease

The apolipoprotein E4 isoform (apoE4) was initially identified as a susceptibility gene for the development of Alzheimer's disease, and has also recently been associated with poor outcome after acute traumatic and ischemic brain injury. One mechanism by which apoE may influence outcome in acute and chronic neurological disease is by downregulating glial activation and the neuroinflammatory response. Because it does not readily cross the blood-brain barrier (BBB), the apoE holoprotein has limited therapeutic potential. However, smaller peptides derived from the receptor binding region of apoE have been developed that mimic the functional anti-inflammatory and neuroprotective effects of the intact apoE protein. These apoE-derived therapeutic peptides cross the BBB and have been demonstrated to improve functional and histological outcomes in murine models of brain injury. Thus, the development of apoE-derived peptides represent a novel therapeutic strategy for the treatment of acute and chronic neurological disease.

[Multiple sclerosis--difficult answers to easy questions]

Multiple sclerosis is an autoimmune disease of the nervous system leading to irreversible disability. The illness affects young, professionally and socially active adults. Patients ask their neurologists many questions concerning prognosis and their future lifestyle. The paper discusses factors enabling us to predict the course of the disease based on clinical data and findings of additional examinations. The authors present the effects of external factors such as temperature, stress, infections and preventive vaccination on relapse as well as their importance for long-term progression of the disease. Moreover, the current results of examinations evaluating the influence of pregnancy and delivery on the risk of relapse and deterioration of disability in the immediate and remote postpartum period and the importance of diet and rehabilitation are presented.

Airway acidification: interactions with nitrogen oxides and airway inflammation

Airway acidification is increasingly appreciated to occur in inflammatory obstructive airway diseases, resulting from acid reflux and aspiration and from direct acid formation in the airways. Acidity activates oxidants and nitrogen oxides to create a potent antimicrobial environment. Neurogenic inflammation is triggered by airway or esophageal acidification, innate immune cells are affected by acidity, and there are pathways by which the acquired immune system also can be activated by the chemistry of an acidic airway. Measuring airway acidity is now readily achievable with noninvasive breath assays, a procedure that has opened a window on the need to understand airway pH homeostasis in health and pH dysregulation in disease.

Enhanced susceptibility to periodontitis in an animal model of depression: reversed by chronic treatment with the anti-depressant tianeptine

OBJECTIVE

To test the hypothesis that the olfactory bulbectomy model of depression in rats could influence susceptibility to ligature-induced periodontitis, and that chronic treatment with the anti-depressant drug tianeptine could attenuate this effect.

MATERIAL AND METHODS

Tianeptine was given twice daily (10 mg/kg, i.p.) during the entire experiment, starting 29 days before induction of olfactory bulbectomy and periodontitis. Olfactory bulbectomized (OB) rats and sham-operated rats were given saline in a similar manner. Periodontal disease was assessed when the ligatures had been in place for 21 days. Two hours before decapitation, rats were injected with lipopolysaccharide (LPS;100 microg/kg, i.p.) to induce a robust immune and stress response.

RESULTS

Compared with sham-operated controls, OB rats developed significantly more periodontal bone loss, exhibited characteristic behavioural responses in a novel open field test, and showed a decreased expression of glucocorticoid receptors (GRs) in the hippocampus. LPS provoked a significantly larger increase in circulating levels of the stress hormone corticosterone and the cytokine transformation growth factor (TGF)-1beta but smaller tumour necrosis factor (TNF)-alpha levels. Tianeptine treatment of OB rats significantly inhibited peridodontal bone loss, normalized behavioural responses, enhanced TGF-1beta levels, and abolished TNF-alpha decrease, but did not attenuate the increased corticosterone response and the decreased hippocampal GR expression.

CONCLUSIONS

These experimental results are consistent with an emerging literature showing that life stress, anxiety, depression, pathological grief, and poor coping behaviour may dysregulate regulatory mechanisms within the brain involved in immune regulation, and thereby alter immune responses and influence the susceptibility/resistance to inflammatory disorders.

Accumulation of irreversible disability in multiple sclerosis: from epidemiology to treatment

There is convincing evidence that neurological relapses in multiple sclerosis (MS) are the clinical counterpart of acute focal inflammation of the central nervous system (CNS) whereas neurological progression is that of chronic diffuse neurodegeneration. The classical view is to consider that MS is an organ-specific autoimmune disease, i.e. that inflammation is the cause of the neurodegeneration. The succession of relapses eventually leads to accumulation of disability and clinical progression results from subclinical relapses. A series of recent observations tends to challenge this classical concept. Important observations have come from the study of the natural history of MS. In the Lyon MS cohort, accumulation of irreversible disability appeared not to be affected by clinically detectable neurological relapses. This has also been shown to be "amnesic" for the early clinical characteristics of the disease, and essentially age-dependent. Suppressing relapses by disease-modifying agents does not dramatically influence the progression of irreversible disability. Interferons beta reduce the relapse rate by 30% and conventional MRI activity by more than 50%. In spite of this effect on inflammation, the effect on disability is only marginal and possibly relapse-reduction-dependent. Administration of Campath-1H to patients with very active disease in terms of frequency of relapses, accumulation of disability and MRI activity, results in a profound, prolonged lymphopenia and the suppression of clinical and MRI activity, but in spite of this, clinical disability and cerebral atrophy still progress. The same experience has been reported with cladribine and autologous haematopoietic stem cell transplantation. All these observations give support to the fact that relapses do not essentially influence irreversible disability in the long term in MS. They are consistent with what has been shown at the individual level in the 1970s by performing serial quantitative neurological examinations over several years, and with what is currently emerging from early and serial structural brain MRI studies. These breakthroughs have immediate implications for the counselling of patients with MS. They suggest that MS is as much neurodegenerative as inflammatory, and should cause the modification of disease-modifying therapeutic strategies by focussing on the protection and repair of the nervous system and not only on the control of inflammation.

Role of neurogenic inflammation in pancreatitis and pancreatic pain

Pain arising from pancreatic diseases can become chronic and difficult to treat. There is a paucity of knowledge regarding the mechanisms that sensitize neural pathways that transmit noxious information from visceral organs. In this review, neurogenic inflammation is presented as a possible amplifier of the noxious signal from peripheral organs including the pancreas. The nerve pathways that transmit pancreatic pain are also reviewed as a conduit of the amplified signals. It is likely that components of these visceral pain pathways can also be sensitized after neurogenic inflammation.

Clinical and experimental aspects of cutaneous neurogenic inflammation

The aim of this paper is to present the state of knowledge on cutaneous neurogenic inflammation. Peripheral effector functions served by afferent sensory neurons underlie the so-called neurogenic inflammation. The mechanism of cutaneous neurogenic inflammation is connected with the release of neuropeptides from the sensory endings. They also exert a number of functions within the immune system. The activity of neuropeptides in the inflammation of the skin can be observed in the form of erythema, edema, hyperthermia and pruritus. Beside these peptides and their receptors, inflammatory skin response, is regulated by tryptase and proteinase-activated receptor 2 (PAR-2). Capsaicin decreases effects of inflammation-induced sensory neuropeptides, which was used in the treatment of diseases caused by inflammation. The activity of transient receptor potential vanilloid receptor 1 (TRP-V1) is associated with the neurogenic inflammation. In inflammatory processes, the neuro-immuno-cutaneous system undergoes activation, which is responsible for triggering and maintaining the inflammatory conditions, both in the healthy skin as well as in the pathological conditions, like psoriasis. Skin exposure to UV radiation influences the neuro-immuno-cutaneous system and causes the release of neuropeptides, thereby eliciting inflammatory response in photodermatosis. In conclusion, understanding the mechanisms and the factors controlling neurotransmitters and their receptors will lead to the identification of novel therapeutic targets for the treatment of cutaneous diseases e.g. pruritus, psoriasis, alopecia areata.

A pilot study of nitric oxide blood levels in patients with chronic orofacial pain

BACKGROUND

Control of pain is the major goal in the management of chronic orofacial pain (COP) patients. The pathogenesis of COP is currently not well understood. Consequently, the treatment of COP may be suboptimal or even harmful. Based on independent observations, we propose that local elevated levels of nitric oxide (NO) may have a central role in the pathogenesis of COP.

HYPOTHESIS

NO level in the orofacial region of COP patients is elevated. A regional increased level of NO causes excessive vasodilatation. This hyperperfusion is manifested by hyperthermia of the overlying skin, while NO enhances nociception, aggravating orofacial pain. An alternative mechanism involving NO as a neurotransmitter at the CNS level may contribute to orofacial pain, but seems not to account for all the known clinical observations.

METHODS

Two groups of subjects were studied: 5 patients with COP and 59 control subjects. For each subject we collected blood samples for analysis of nitrite\nitrate (or NOx).

RESULTS

(1) NOx blood levels for 5 patients diagnosed with COP was 65.9 microM (SD of 10.4) verses 42.7 microM (SD of 24.2) for 59 control subjects, the difference being statistically significant, t-statistic = -2.12 (P > .05). (2) No statistical difference was found for NOx blood levels for 59 control subjects divided by gender (male vs female), with 23 female controls having NOx blood levels of 42.6 microM (SD of 25.2) and male controls having NOx blood levels of 42.8 microM (SD of 24.0), t-statistic = -0.03, P = .98.

CONCLUSION

This pilot study suggests that NO blood levels may have an association with COP. A better understanding of the mechanism of chronic orofacial pain is expected to lead to more precise diagnostic staging and management of this disorder.

Effects of an acetone extract of Boswellia carterii Birdw. (Burseraceae) gum resin on rats with persistent inflammation

OBJECTIVE

Ruxiang, or Gummi olibanum, an herbal medicine derived from the gum resin of Boswellia carterii Birdw. (BC) of the family Burseraceae, has been used traditionally in China to alleviate pain and reduce inflammation. The present study is an investigation of the effects of a BC extract on persistent hyperalgesia and edema in rats with peripheral inflammation.

DESIGN

In this randomized, blinded study, the antihyperalgesic and antiedema effects of 3 dosages of BC were compared to a vehicle control. Inflammation was induced in rats by injecting complete Freund's adjuvant (CFA) into one hind paw. A single oral dose of the BC extract was administered daily for 7 days, beginning one day before CFA. Hyperalgesia was assessed using a paw withdrawal latency (PWL) test pre-CFA and 2 hours, 5 hours, 1 day, and 5 days post-CFA. Edema was determined by measuring paw thickness at the same time points. Spinal Fos protein expression was analyzed 2 hours post-CFA. Adverse effects of the extract were monitored by observing the animals closely for unusual behavioral changes.

RESULTS

Compared to control, a dosage of 0.45 g/kg BC significantly lengthened PWL and reduced paw edema on day 5 post-CFA. At 0.90 g/kg, BC significantly lengthened PWL at 5 hours, 1 day, and 5 days, and reduced paw edema at 2 hours, 5 hours, 1 day, and 5 days. This dosage also significantly suppressed spinal Fos expression in the medial half of laminae I-II. At 1.80 g/kg, BC significantly lengthened PWL and reduced paw edema at all time points. No noticeable adverse effects were observed in animals given the lower dosages of BC, but adverse effects in some animals were observed at 1.80 g/kg per day. In the acute toxicity study, the maximal single dose of 2.50 g/kg produced no adverse effects in the treated rats during the 14 days of observation.

CONCLUSIONS

The data suggest that BC produces significant antihyperalgesia and anti-inflammation effects and that the antihyperalgesia may be mediated by suppressed inflammation-induced Fos expression in the spinal dorsal horn neurons.

Neurogenic inflammation in acute pancreatitis

Acute pancreatitis is a clinical condition whose incidence has increased over the past few years. The exact mechanism of its development is not yet clear. Substance P, the proinflammatory neuropeptide, has a role in the initiation of neurogenic inflammation. Substance P and its receptor neurokinin-1 receptor (NK-1R) are involved in the development of local as well as systemic inflammation in acute pancreatitis. This editorial focuses on the role of substance P and its receptors in the development of acute pancreatitis.

Endogenous cannabinoid receptor agonists inhibit neurogenic inflammations in guinea pig airways

BACKGROUND

Although neurogenic inflammation via the activation of C fibers in the airway must have an important role in the pathogenesis of asthma, their regulatory mechanism remains uncertain.

OBJECTIVE

The pharmacological profiles of endogenous cannabinoid receptor agonists on the activation of C fibers in airway tissues were investigated and the mechanisms how cannabinoids regulate airway inflammatory reactions were clarified.

METHODS

The effects of endogenous cannabinoid receptor agonists on electrical field stimulation-induced bronchial smooth muscle contraction, capsaicin-induced bronchoconstriction and capsaicin-induced substance P release in guinea pig airway tissues were investigated. The influences of cannabinoid receptor antagonists and K+ channel blockers to the effects of cannabinoid receptor agonists on these respiratory reactions were examined.

RESULTS

Both endogenous cannabinoid receptor agonists, anandamide and palmitoylethanolamide, inhibited electrical field stimulation-induced guinea pig bronchial smooth muscle contraction, but not neurokinin A-induced contraction. A cannabinoid CB2 antagonist, SR 144528, reduced the inhibitory effect of endogenous agonists, but not a cannabinoid CB1 antagonist, SR 141716A. Inhibitory effects of agonists were also reduced by the pretreatment of large conductance Ca2+ -activated K+ channel (maxi-K+ channel) blockers, iberiotoxin and charybdotoxin, but not by other K+ channel blockers, dendrotoxin or glibenclamide. Anandamide and palmitoylethanolamide blocked the capsaicin-induced release of substance P-like immunoreactivity from guinea pig airway tissues. Additionally, intravenous injection of palmitoylethanolamide dose-dependently inhibited capsaicin-induced guinea pig bronchoconstriction, but not neurokinin A-induced reaction. However, anandamide did not reduce capsaicin-induced guinea pig bronchoconstriction.

CONCLUSIONS

These findings suggest that endogenous cannabinoid receptor agonists inhibit the activation of C fibers via cannabinoid CB2 receptors and maxi-K+ channels in guinea pig airways.

Complex regional pain syndrome

Complex regional pain syndrome (CRPS) may develop after limb trauma and is characterized by pain, sensory-motor and autonomic symptoms. Most important for the understanding of the pathophysiology of CRPS are recent results of neurophysiological research. Major mechanism for CRPS symptoms, which might be present subsequently or in parallel during the course of CRPS, are trauma-related cytokine release, exaggerated neurogenic inflammation, sympathetically maintained pain and cortical reorganisation in response to chronic pain (neuroplasticity). The recognition of these mechanisms in individual CRPS patients is the prerequisite for a mechanism-oriented treatment.

Neurogenic inflammation and pancreatitis

Stimulation of primary sensory neurons produces local vasodilation, plasma extravasation, and pain and is due largely to the release of the tachykinins substance P and calcitonin-gene-related peptide. Pathological activation of sensory neurons and the inflammatory sequelae are known as neurogenic inflammation and appear to be important in many organ systems, including the pancreas. Factors that stimulate primary sensory neurons include hydrogen ions, heat, leukotrienes, arachidonic acid metabolites, bradykinin, and proteases such as trypsin, all of which may participate in the generation of acute pancreatitis. The current review examines the cellular and molecular mechanisms involved in sensory nerve activation within the pancreas and the potential contribution of neurogenic inflammation to the pathogenesis of pancreatitis.

Neuropeptides stimulate production of interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha in human dental pulp cells

OBJECTIVE

Orthodontic tooth movement causes inflammatory reactions in the periodontal membrane and dental pulp. It has been reported that substance P (SP) and calcitonin gene-related peptide (CGRP), both sensory neuropeptides, are manifested in the dental pulp of rats during experimental tooth movement, suggesting that they might be involved in the dental pulp inflammation during orthodontic tooth movement. However, the relationships between neuropeptides and pro-inflammatory cytokines have not been fully elucidated.

MATERIALS AND METHODS

Human dental pulp (HDP) fibroblasts were prepared from 6 healthy young volunteers (3 males, 3 females; 15-25 years old) during the course of orthodontic treatment. HDP cells were incubated for 24 h in fresh medium containing 2% FCS in the presence of various concentrations of CGRP (10(-12) to 10(-4) M) and SP (10(-12) to 10(-4) M), and the levels of interleukin (IL)-1 beta, IL-6, and tumor necrosis factor (TNF)-alpha present in the media were determined using commercially available high-sensitivity enzyme-linked immunosorbent assay kit.

RESULTS

We examined the effects of stimulation by these neuropeptides on the production of inflammatory cytokines in HDP fibroblasts, and found that the levels of IL-1 beta, IL-6, and TNF-alpha increased in a time- and concentration-dependent manner. However, the neuropeptides did not act synergistically to increase cytokine secretion in HDP cells or significantly modify LPS-induced cytokine production by HDP cells.

CONCLUSIONS

Our results suggest that human pulp fibroblasts may be involved in the progress of inflammation in pulp tissue during orthodontic tooth movement, as they produced large amounts of IL-1 beta, IL-6, and TNF-alpha following stimulation with neuropeptides.

Studies on ocular inflammation and development of a prostaglandin analogue for glaucoma treatment

This review summarizes the Ernst H. Bárány Prize Lecture given at the meeting of the International Society of Eye Research in Geneva 2002. In the paper the path from the author's early studies on neurogenic inflammation in the eye to the search for a suitable prostaglandin analogue for glaucoma treatment, and the development of latanoprost are described. In particular the solution to the nociceptive and hyperemic side-effects of naturally occurring prostaglandins in the eye, the mechanism of action of FP prostanoid receptor agonists as well as the selection of dose for glaucoma treatment are discussed. In addition, pharmacokinetical aspects of latanoprost, and the melanogenic side-effect of prostaglandins in the iris are addressed. The paper is primarily focused on studies performed by the author and complete reference to other previous, or contemporary studies is therefore not always given as the purpose is not to present a comprehensive review article.

The role of neurotrophins in bronchial asthma: contribution of the pan-neurotrophin receptor p75

Allergic bronchial asthma is characterized by chronic inflammation of the airways, development of airway hyperreactivity and recurrent reversible airway obstruction. Target and effector cells responsible for airway hyperresponsiveness and airway obstruction include sensory and motor neurons as well as epithelial and smooth muscle cells. Although it is well established that the inflammatory process is controlled by T-helper-2 (Th2) cells, the mechanisms by which immune cells interact with neurons, epithelial cells or smooth muscle cells still remain uncertain. Due to growing evidence for extensive communication between neurons and immune cells, the mechanisms of this neuroimmune crosstalk in lung and airways of asthmatic patients are becoming the focus of asthma research. Neurotrophins represent molecules potentially responsible for regulating and controlling the crosstalk between the immune and peripheral nervous system. They are constitutively expressed by resident lung cells and produced in increasing concentrations by immune cells invading the airways under pathological conditions. Neurotrophins modify the functional activity of sensory and motor neurons, leading to enhanced and altered neuropeptide and tachykinin production. These effects are defined as neuronal plasticity. The consequences are the development of neurogenic inflammation.

Role of NGF and neurogenic inflammation in the pathogenesis of psoriasis

A contributing role of neurogenic inflammation has provided a new dimension in understanding the pathogenesis of various cutaneous and systemic inflammatory diseases such as atopic dermatitis, urticaria, rheumatoid arthritis, ulcerative colitis and bronchial asthma. Several critical observations, such as (i) psoriasis resolves at sites of anaesthesia, (ii) neuropeptides are upregulated, and (iii) there is a marked proliferation of terminal cutaneous nerves in psoriatic plaques, encouraged us to search for a mechanism of neural influence in inflammation and inflammatory diseases. In immunohistochemical studies, we found that keratinocytes in lesional and nonlesional psoriatic tissue express high levels of nerve growth factor (NGF) and that there is a marked upregulation of NGF receptors, p75 neurotrophin receptor (p75NTR) and tyrosine kinase A (TrkA), in the terminal cutaneous nerves of psoriatic lesions. As keratinocytes of psoriatic plaques express increased levels of NGF, it is likely that murine nerves will promptly proliferate into the transplanted plaques on a severe combined immunodeficient mouse. Indeed, we have noted marked proliferation of nerve fibers in transplanted psoriatic plaques compared with the few nerves in transplanted normal human skin. By double label immunofluorescence staining, we have further demonstrated that in these terminal cutaneous nerves there is a marked upregulation of neuropeptides, such as substance P and calcitonin gene-related protein. These observations, as well as recent findings about NGF-induced chemokine expression in keratinocytes, further substantiate a role of the NGF-p75NTR-TrkA system in the inflammatory process of psoriasis. Currently, we are evaluating antagonists to selected neuropeptides and NGF/receptors, with the expectation of identifying pharmacological agents to counter neurogenic inflammation in psoriasis.

[The role of neuromodulators (substance P and calcitonin gene-related peptide) in the development of neurogenic inflammation in the oral mucosa]

Vatous observations carried out in the course of the years have shown that certain neuropeptides have a possible role to play as inflammation mediators. The substances on which attention has been principally focused are: substance P, calcitonin gene-related peptide, capsaicin an histamine. Knowledge acquired in this field, however, does not yet permit us to sufficiently clarify the role, not to speak of the possible action mechanism, on the basis of which these neuropeptides act, although it is confirmed that these substances have been found first in laboratory animals and later also in human tissues in the course of experimentally induced neurogenic inflammation. The need to know more and more about inflammatory mechanisms and the increasingly complex possibilities offered by the application of technology in the field of medical research have led to many small advance in our knowledge of what is involved in inflammation. In fact it has been understood that behind the typical signs of inflammation (the famous four cardinal signs of Celsus: pain, redness, swelling, heat) no abstract entities or strange alchemies are concealed, but a series of well-known, classified substance, the so-called "inflammation mediators", namely a variety of substances of cellular or plasmatic origin united by the fact that exist, in stationary state conditions, in the form of inactive precursors, or sequestered in intracellular sites where they are unable to carry out their action. Following an inflammatory stimulus, they are activated, or their synthesis can be induced, or their release from intracellular sequestration sites in favoured; in any case they are stored in the disturbance district in concentrations that are such as to act on their respective targets, triggering event s that characterise the various stages of the inflammatory process.

Neurogenic inflammation in primary headaches

The headache in migraine is thought to result from neuronal nociceptive activity in the trigeminovascular system, that is, the meninges. In addition, trigeminal axons projecting to the meninges contain vasoactive neuropeptides, such as substance P, calcitonin gene-related peptide and neurokinin A, that may promote, when released, plasma protein leakage and vasodilation within dura mater, characteristic of neurogenic inflammation. Thus, it has been hypothesized that a sterile neurogenic inflammation in the meninges may be involved in generating or sustaining, via occurrence of a vicious cycle, the pain accompanying the migraine attacks. We here review the evidence in support of this hypothesis as well as its potential significance in better tailoring therapies in migraine or other types of primary headaches.

Emboli, inflammation, and CNS impairment: an overview

Perioperative stroke occurs in 2-3% of adult cardiac surgery patients, and significant cognitive dysfunction is experienced by 40-60% of patients in the first postoperative week. Perioperative neurocognitive abnormalities are associated with a greatly increased risk of perioperative mortality, lengthy intensive care and hospital stay, and more intensive rehabilitative care. Long-term cognitive dysfunction, ranging from months to years, occurs in 25-40% of adult cardiac surgery patients, resulting in a decreased quality of life. Cerebral emboli are an important cause of perioperative neurocognitive abnormalities. Aortic cannulation, clamping, and manipulation during surgery may dislodge atheromatous materials into the cerebral circulation, leading to perioperative or postoperative stroke. Nevertheless, acute and chronic neurocognitive dysfunction frequently occurs in non-cardiac surgery patients as well, suggesting that some element of surgery and/or anesthesia itself causes or contributes to this phenomenon. One possible cause may be central nervous system (CNS) responses to peripheral tissue injury or inflammation. The CNS is sensitive to systemic pro-inflammatory mediators such as endotoxin and the cytokines interleukin-6 and interleukin- 8, which are activated by surgical trauma. This article discusses the behavior and effects of these inflammatory agents and their intensification in combination with postoperative hyperthermia. The potential beneficial role of pharmacological agents such as heparin, lidocaine, and aprotinin is also examined.

Scintigraphic visualization of inflammation in neurodegenerative disorders

In the past few decades, our understanding of the central nervous system has evolved from one of an immune-privileged site, to one where inflammation is pathognomonic for some of the most prevalent and tragic neurodegenerative diseases. Current research indicates that diseases as diverse as multiple sclerosis, stroke and Alzheimer's disease exhibit inflammatory processes that contribute to cellular dysfunction or loss. Inflammation, whether in the brain or periphery, is almost always a secondary response to a primary pathogen. In head trauma, for example, the blow to the head is the primary event. What typically concerns the neurologist and neurosurgeon more, however, is the secondary inflammatory response that will ensue and likely cause more neuron loss than the initial injury. This paper reviews the basic neuroinflammatory mechanisms, the potential neurotoxic mediators during activation of microglia, the brain resident macrophages, and their role in neurodegeneration. Alzheimer's disease is taken as a prototype for exploring these mechanisms, as it expresses more than 40 inflammatory mediators, it is the most extensively studied disorder in terms of immune-related pathogenesis, and because of its importance as the most prevalent type of dementia. Tools for the visualization of these neuroinflammatory processes, both structural and mainly functional, are critically reviewed and discussed.

The involvement of nervous and some inflammatory response mechanisms in the acute snuff-induced gingival hyperaemia in humans

BACKGROUND AND AIM

Tobacco users and especially cigarette smokers are at higher risk than non-smokers for periodontal disease. The pathogenic mechanism has been proposed to be the vasoconstrictive properties of nicotine, with reduced gingival blood flow (GBF) as a contributing factor in the development of periodontal disease. However, in a previous study in humans, we found GBF to increase in response to acute exposure to snuff. The present study was designed to investigate whether the tobacco-induced acute GBF increase is dependent on intact nervous conduction. We further investigated the effect of piroxicam (NSAID) and dexchlorpheniramin (DCPA) (antihistamine) on the snuff-induced responses in the gingiva, to see if chemical mediators of inflammation also influenced the response.

MATERIAL AND METHODS

Laser Doppler flowmetry (LDF) was used to measure gingival blood flow bilaterally in the buccal maxillary gingiva, in the forehead skin and in the thumb. Also arterial blood pressure (BP) and heart rate (HR) were monitored. Infraorbital nerve block anaesthesia (INB), superficial mucosal anaesthesia, 20 mg piroxicam or 2 mg DCPA were used in combination with snuff to study the vascular responses to 500 mg snuff (1% nicotine).

RESULTS

Snuff induced a rapid increase in GBF that was higher than the increase in BP, indicating an active vasodilatation. The snuff-induced vasodilatation was partly blocked by INB and more so by superficial mucosal anaesthesia. Piroxicam and DCPA exerted diverse effects on vascular homeostasis but had no effect on the snuff-induced vasodilatation in the gingiva.

CONCLUSIONS

The results of this study confirm that snuff induces local gingival vasodilatation, and imply that this vasodilatation most likely is a summation of responses due to both autonomic and antidromic reflex mechanisms. We further discuss the possible involvement of the nervously mediated effects of tobacco and nicotine on vascular homeostasis and in tobacco-associated periodontitis.

Modulatory effect of two novel CGRP receptor antagonists on nasal vasodilatatory responses to exogenous CGRP, capsaicin, bradykinin and histamine in anaesthetised pigs

Calcitonin gene-related peptide (CGRP) is a 37-amino acid peptide and potent vasodilatator agent located in sensory C fibres. Several functional studies suggest that CGRP could be involved in the vasodilatation of different vascular beds during neurogenic inflammation. We have studied, in pentobarbital anaesthetised pigs, the antagonistic effect of local intra-arterial (i.a.) pretreatment with the analogues CGRP 8-37, [D31, P34, F35]CGRP 27-37 and [N31, P34, F35]CGRP 27-37 on the vasodilatation of the nasal vascular bed induced by exogenous CGRP, capsaicin, bradykinin (BK) and histamine. The attenuating effect of CGRP 8-37 analogue on exogenous CGRP-induced vasodilatation, previously described in other in vivo animal models, was confirmed in the pig nasal mucosa. It also interfered with BK-and, to a lesser extent, with capsaicin-and histamine-induced decrease in vascular resistance. CGRP 27-37 analogues reduced the duration of CGRP-, capsaicin- and BK-induced vasodilatation by more than 50%. Peak values of vasodilatation were attenuated by more than 25% overall. Attenuation of histamine-induced decrease in vascular resistance was less pronounced. It is concluded that CGRP 27-37 analogues antagonise the action of exogenous CGRP, capsaicin, BK and histamine by attenuating their vasodilatation effect, both in intensity and duration. These results strongly suggest that BK- and histamine-induced vasodilatation is partly mediated by CGRP. CGRP 8-37 and 27-37 appear to be potential contributors to the study of CGRP and its physiological role in neurogenic inflammation. In addition, they may have putative therapeutic applications in the treatment of rhinitic patients suffering from chronic nasal obstruction.

[Involvement of peripheral 5-HT2A receptor activation in inflammatory pain]

Serotoninergic neuron is concerned as an one of the pivotal factor of the tissue inflammation which lead to pain behavior. Sarpogrelate HCl is a novel compound which may modulate inflammatory reaction through 5-HT2A receptor antagonist. We show the involvement of the 5-HT2A receptor activity in the inflammatory and neuropathic pain. Systemic or local sarpogrelate administration provokes antinociceptive effect on 5-HT- or formalin-produced inflammatory pain behaviour in relation to spinal glutamate. Local sarpogrelate inhibits apoptosis and neuronal degeneration after chronic construction injury(CCI). These effects are reversed by 5-HT2A receptor agonist. These results suggests sarpogrelate has a beneficial effect on hyperalgesia and neuropathic pain via inhibiting 5-HT2A receptor.

The effect of unilateral sympathectomy and cavity preparation on peptidergic nerves and immune cells in rat dental pulp

Recent evidence suggests interactions between primary afferent nociceptors and postganglionic sympathetic efferents in the pathogenesis of inflammation. The effect of unilateral removal of the superior cervical ganglion on the innervation pattern of nerve fibers immunoreactive (IR) to calcitonin gene-related peptide (CGRP), substance P (SP), and neuropeptide Y (NPY), as well as the occurrence of immune cells in the injured and uninjured rat molar pulp, was investigated. Light microscopic immunocytochemistry demonstrated that the molar pulps contralateral to the sympathectomy contained a NPY-IR nerve fiber network more dense and heavily stained than unoperated control rats. The NPY-IR fibers showed, however, no sprouting after deep cavity preparation. There was no compensatory increase in CGRP- and SP-IR nerve fibers in the dental pulp after unilateral sympathectomy, although a significant increase in cells IR to CGRP and SP was found in the ipsilateral trigeminal ganglion. Unilateral sympathectomy induced a significant increase in immune cell density both in the inflamed and in the uninflamed dental pulp bilaterally. Our results demonstrate, for the first time, a trophic effect of the sympathetic nerves on immune cells in the dental pulp, indicating that an imbalance of sympathetic nerves may induce inflammation and pain in teeth.

[Respiratory syncytial virus infection and asthma]

Presentation of bronchial asthma, in the years following the first outbreak of bronchiolitis due to respiratory syncytial virus (RSV) was first described by McIntosh, who postulated a common pathogenesis that was confirmed by the greater frequency (50%) of wheezing bronchiolitis and asthma during the more than 5 year follow up of these children. More recently, Hibbert and Schroechkenstein have again confirmed this phenomenon. These authors report that the percentage of asthma was increased by up to 71% in a group of children who contracted bronchiolitis during the first year of life and who were closely followed-up for 5 years after the outbreak. Other authors report figures between 25% and 57%. Stein et al. followed-up 888 children with RSV bronchiolitis until the age of 13 years and observed that at the age of 3-5 years 69% had asthma, at 4-5 years 55% did so and at 6-8 years 31% were asthmatic. In our experience of children who developed RSV bronchiolitis before the age of 6 months, 58 of 75 developed infantile asthma in following 3 years. Seventeen infants were aged more than 6 months at onset of bronchiolitis and of these 5 had bronchiolitis. We carried out a prospective study of 50 children aged 3-7 months with RSV bronchiolitis from December 1997 to February 1998. Follow-up was until the year 2000. Of these children, 22 (44%) had asthma and the remaining 28 (56%) had isolated episodes of cough and wheezing, which did not fulfill the criteria for asthma. Of the 22 children with asthma, all presented elevated total IgE by the second year of follow-up but only one of the children presented hypersensitivity to egg. The breathing difficulties that appeared in the initial outbreak of bronchiolitis is well explained by the cytopathic effect of the virus on the airways of infants. RSV virus produces inflammation of the bronchial mucosa, the effects of which may persist for 6-7 weeks, even after recovery from the first episode. The damaged and denuded epithelium provides fertile ground for future viral reinfections which, although less severe, produce dyspnea due to irritation of the exposed vagal receptors. Irrespective of the mechanism involved (RSV, histamine, methacholine or ozone inhalation) inflammation alters the intercellular junctions of the bronchial mucosal epithelium which, even in the absence of significant necrotic lesions, leads to increased penetration of irritants and stimulates the vagal receptors, leading to bronchospasm. In conclusion, it can currently be stated that RSV bronchiolitis constitutes a risk factor for the development of infantile asthma. The risk is increased in children with familial or personal antecedents of atopy. Serious forms of bronchiolitis due to RSV are more frequent in atopic individuals. The appearance of extrinsic asthma is more frequent in children who have previously had RSV bronchiolitis than in those who have not.

Electrically evoked neuropeptide release and neurogenic inflammation differ between rat and human skin

Protein extravasation and vasodilatation can be induced by neuropeptides released from nociceptive afferents (neurogenic inflammation). We measured electrically evoked neuropeptide release and concomitant protein extravasation in human and rat skin using intradermal microdialysis. Plasmapheresis capillaries were inserted intradermally at a length of 1.5 cm in the volar forearm of human subjects or abdominal skin of rats. Capillaries were perfused with Ringer solution at a flow rate of 2.5 or 1.6 microl min(-1). After a baseline period of 60 min capillaries were stimulated electrically (1 Hz, 80 mA, 0.5 ms or 4 Hz, 30 mA, 0.5 ms) for 30 min using a surface electrode directly above the capillaries and a stainless-steel wire inserted in the capillaries. Total protein concentration was assessed photometrically and calcitonin gene-related peptide (CGRP) and substance P (SP) concentrations were measured by enzyme-linked immunosorbent assay (ELISA). In rat skin, electrical stimulation increased CGRP and total protein concentration in the dialysate. SP measurements showed a larger variance but only for the 1 Hz stimulation was the increased release significant. In human skin, electrical stimulation provoked a large flare reaction and at a frequency of 4 Hz both CGRP and SP concentrations increased significantly. In spite of the large flare reactions no protein extravasation was induced, which suggests major species differences. It will be of interest to investigate whether the lack of neurogenic protein extravasation is also valid under pathophysiological conditions.

The effect of a sciatic nerve block on the development of inflammation in carrageenan injected rats

Neurogenic inflammation may participate in postoperative inflammatory pain. We evaluated, in the rat, the influence of a short and prolonged sciatic nerve block on carrageenan-induced inflammation, the time course of which may be compared to postoperative inflammation. A catheter was placed on the right sciatic nerve and injected with 0.5% bupivacaine with epinephrine (0.2 mL): one injection in the Short Block Group, and four injections performed at 90-min intervals in the Prolonged Block Group. In all groups, the two hind paws were then injected with carrageenan. The development of inflammation was evaluated in both hind paws by measurement of paw circumference (PC) before, and 1, 2, 3, 4, 6, and 24 h after carrageenan injection. Temperature of both hind paws was evaluated at the same time points. The vocalization threshold to paw pressure test (VTPP) of both hind paws was evaluated at 6, 8, 10, 12, and 24 h after carrageenan injection. The left hind paw was used for the Control Group. A Sham Group had a catheter placed on the sciatic nerve and injected with normal saline. Inflammation developed in the Control Group with a maximum increase of PC (32%) and temperature (14%) 4 h after carrageenan injection and a maximal reduction of VTPP (44%) at 6 h, reflecting mechanical allodynia. A similar evolution was observed in the Sham Group. In the Short Block Group, the nerve block did not influence the PC, the paw temperature, or the VTPP when compared with the Control Group. In the Prolonged Block Group, when compared with the Control Group, the increased PC was reduced throughout the 24 h (P < 0.0001). The maximal increase in PC at 4 h was limited to 23%, as compared with the precarrageenan value. This effect on PC did not persist at 24 h. Paw temperature was increased (P = 0.07) throughout the study in the Prolonged Block Group, as compared with the Control Group. The VTPP reduction was still limited in the Prolonged Block Group at 24 h, as compared with the Control Group (P < 0.0001). We conclude that a prolonged sciatic nerve block limits carrageenan-induced increase in PC and, subsequently, mechanical allodynia at 24 h in rats.

IMPLICATIONS

Our study has shown that a prolonged (6 h) but not a short sciatic nerve block (90 min) can limit edema and related pain after carrageenan-induced inflammation in rat.

Effects of selective slow wave sleep disruption on musculoskeletal pain and fatigue in middle aged women

OBJECTIVE

To determine whether disrupted slow wave sleep (SWS) would evoke musculoskeletal pain, fatigue, and an alpha electroencephalograph (EEG) sleep pattern. We selectively deprived 12 healthy, middle aged, sedentary women without muscle discomfort of SWS for 3 consecutive nights. Effects were assessed for the following measures: polysomnographic sleep, musculoskeletal tender point pain threshold, skinfold tenderness, reactive hyperemia (inflammatory flare response), somatic symptoms, and mood state.

METHODS

Sleep was recorded and scored using standard methods. On selective SWS deprivation (SWSD) nights, when delta waves (indicative of SWS) were detected on EEG, a computer generated tone (maximum 85 decibels) was delivered until delta waves disappeared. Musculoskeletal tender points were measured by dolorimetry; skinfold tenderness was assessed by skin roll procedure; and reactive hyperemia was assessed with a cotton swab test. Subjects completed questionnaires on bodily feelings, symptoms, and mood.

RESULTS

On each SWSD night, SWS was decreased significantly with minimal alterations in total sleep time, sleep efficiency, and other sleep stages. Subjects showed a 24% decrease in musculoskeletal pain threshold after the third SWSD night. They also reported increased discomfort, tiredness, fatigue, and reduced vigor. The flare response (area of vasodilatation) in skin was greater than baseline after the first, and again, after the third SWSD night. However, the automated program for SWSD did not evoke an alpha EEG sleep pattern.

CONCLUSION

Disrupting SWS, without reducing total sleep or sleep efficiency, for several consecutive nights is associated with decreased pain threshold, increased discomfort, fatigue, and the inflammatory flare response in skin. These results suggest that disrupted sleep is probably an important factor in the pathophysiology of symptoms in fibromyalgia.

Neural modulation of inflammatory reactions in dental tissues incident to orthodontic tooth movement. A review of the literature

This article reviews the current knowledge of the biological aspects of dental tissue changes incident to orthodontic tooth movement. The inflammatory nature of these tissue changes was first recognized in the early 1970s, and since then a number of morphological and quantitative investigations have been published in support of this view. The studies dealing with vascular and cellular dental tissue changes, as well as those concerned with inflammatory mediators present at sites of orthodontic tooth movement are systematized and presented accordingly. Special emphasis is placed upon the role of the sensory nerve fibres and their neuropeptides in the control, and development of an inflammatory process, i.e. their role in tooth movement.

Analysis of the inflammatory response induced by substance P in the mouse pleural cavity

This study analyzes both cell migration and exudation responses elicited by substance P (SP) in the mouse pleural cavity. SP caused, 4 h after its administration into the mouse pleural cavity, a dose-related recruitment of leukocytes (ED50 = 14.2 nmol), mainly due to mononuclears. Leukocytes peaked between 2 and 4 h, being followed by a slight decay that remained elevated for up to 24 h. Exudation, although small, was significantly elevated from 2 to 96 h after. NK1 (FK 888) or NK3 (SR 142801), but not NK2 (SR 48968) tachykinin receptor antagonists, significantly inhibited cell migration. HOE 140 and NPC 17731, bradykinin B2 receptor antagonists, caused graded inhibition of cell influx (ID50s of 0.03 and 0.04 pmol), but des-Arg9-Leu8-BK, B1 receptor antagonist, had no effect. The nitric oxide inhibitors L-NOARG and L-NAME, but not D-NAME, significantly inhibited SP-induced pleurisy. Pretreatment of the animals with indomethacin, dexamethasone, terfenadine, theophylline or salbutamol produced significant inhibition of the inflammatory parameters, whereas cromolyn only inhibited exudation. These results indicate that intrapleural injection of SP in mice elicit a long-lasting inflammatory reaction that is characterized by the participation of nitric oxide, kinins, cyclooxygenase metabolites and histamine. Antiasthmatic drugs such as theophylline, salbutamol, dexamethasone, and, to a lesser extent cromolyn, also markedly inhibit this inflammatory reaction. These results provide clear evidence supporting the role played by SP in neurogenic inflammation.