Mast cells synthesize, store, and release nerve growth factor

Cutaneous and inflammatory response to long-term percutaneous implants of sphere-templated porous/solid poly(HEMA) and silicone in mice

This study investigates mouse cutaneous responses to long-term percutaneously implanted rods surrounded by sphere-templated porous biomaterials engineered to mimic medical devices surrounded by a porous cuff. We hypothesized that keratinocytes would migrate through the pores and stop, permigrate, or marsupialize along the porous/solid interface. Porous/solid-core poly(2-hydroxyethyl methacrylate) [poly(HEMA)] and silicone rods were implanted in mice for 14 days, and for 1, 3, and 6 months. Implants with surrounding tissue were analyzed (immuno)histochemically by light microscopy. Poly(HEMA)/skin implants yielded better morphologic data than silicone implants. Keratinocytes at the poly(HEMA) interface migrated in two different directions. "Ventral" keratinocytes contiguous with the dermal-epidermal junction migrated into the outermost pores, forming an integrated collar surrounding the rods. "Dorsal" keratinocytes appearing to emanate from the differentiated epithelial layer, extended upward along and into the exterior portion of the rod, forming an integrated sheath. Leukocytes persisted in poly(HEMA) and silicone pores for the duration of the study. Vascular and collagen networks within the poly(HEMA) pores matured as a function of time up to 3-months implantation. Nerves were not observed within the pores. Poly(HEMA) underwent morphological changes by 6 months of implantation. Marsupialization, foreign body encapsulation, and infection were not observed in any implants.

Role of mast cells in male chronic pelvic pain

PURPOSE

Chronic pelvic pain syndrome accounts for 90% of all chronic prostatitis but it has an unknown pathogenesis. We sought to understand the role of mast cells and nerve growth factor in chronic pelvic pain.

MATERIALS AND METHODS

Expressed prostatic secretions in men with chronic pelvic pain syndrome and controls were tested for mast cell tryptase and nerve growth factor. Mast cell number, activation status and nerve growth factor expression were examined in the NOD/ShiLtJ experimental autoimmune prostatitis model and in mast cell deficient KitW-sh/KitW-sh mice. Tactile allodynia was quantified using von Frey filaments as a measure of pelvic pain behavior. Inhibitors of mast cell degranulation, histamine receptor antagonists and anti-nerve growth factor neutralizing antibodies were tested to decrease pelvic pain behavior.

RESULTS

Men with chronic pelvic pain syndrome showed increased mast cell tryptase and nerve growth factor in expressed prostatic secretions. In the experimental autoimmune prostatitis model increased total and activated mast cells were observed in the prostate. Mast cell deficient KitW-sh/KitW-sh mice showed attenuated pelvic pain behavior but no difference in inflammatory infiltrates in the prostate from controls. Mice with experimental autoimmune prostatitis also demonstrated increased intraprostatic nerve growth factor compared to that of KitW-sh/KitW-sh mice. Treatment of experimental autoimmune prostatitis with a mast cell stabilizer combined with a histamine 1 receptor antagonist resulted in a synergistic decrease in chronic pelvic pain. In contrast, neutralization of nerve growth factor in vivo did not result in pain relief.

CONCLUSIONS

Results suggest that mast cells are important mediators of chronic pelvic pain in experimental autoimmune prostatitis cases. They may be potential targets for therapeutic intervention in men with chronic prostatitis/chronic pelvic pain syndrome.

NGF, brain and behavioral plasticity

Nerve Growth Factor (NGF) was initially studied for its role as a key player in the regulation of peripheral innervations. However, the successive finding of its release in the bloodstream of male mice following aggressive encounters and its presence in the central nervous system led to the hypothesis that variations in brain NGF levels, caused by psychosocial stressor, and the related alterations in emotionality, could be functional to the development of proper strategies to cope with the stressor itself and thus to survive. Years later this vision is still relevant, and the body of evidence on the role of NGF has been strengthened and expanded from trophic factor playing a role in brain growth and differentiation to a much more complex messenger, involved in psychoneuroendocrine plasticity.

A Contractile Network of Interstitial Cells of Cajal in the Supratarsal Mueller's Smooth Muscle Fibers With Sparse Sympathetic Innervation

BACKGROUND

We previously reported that the supratarsal Mueller's muscle is innervated by both sympathetic efferent fibers and trigeminal proprioceptive afferent fibers, which function as mechanoreceptors-inducing reflexive contractions of both the levator and frontalis muscles. Controversy still persists regarding the role of the mechanoreceptors in Mueller's muscle; therefore, we clinically and histologically investigated Mueller's muscle.

METHODS

We evaluated the role of phenylephrine administration into the upper fornix in contraction of Mueller's smooth muscle fibers and how intraoperative stretching of Mueller's muscle alters the degree of eyelid retraction in 20 patients with aponeurotic blepharoptosis. In addition, we stained Mueller's muscle in 7 cadavers with antibodies against α-smooth muscle actin, S100, tyrosine hydroxylase, c-kit, and connexin 43.

RESULTS

Maximal eyelid retraction occurred approximately 3.8 minutes after administration of phenylephrine and prolonged eyelid retraction for at least 20 minutes after administration. Intraoperative stretching of Mueller's muscle increased eyelid retraction due to its reflexive contraction. The tyrosine hydroxylase antibody sparsely stained postganglionic sympathetic nerve fibers, whereas the S100 and c-kit antibodies densely stained the interstitial cells of Cajal (ICCs) among Mueller's smooth muscle fibers. A connexin 43 antibody failed to stain Mueller's muscle.

CONCLUSIONS

A contractile network of ICCs may mediate neurotransmission within Mueller's multiunit smooth muscle fibers that are sparsely innervated by postganglionic sympathetic fibers. Interstitial cells of Cajal may also serve as mechanoreceptors that reflexively contract Mueller's smooth muscle fibers, forming intimate associations with intramuscular trigeminal proprioceptive fibers to induce reflexive contraction of the levator and frontalis muscles.

Neurotrophic factor changes in the rat thick skin following chronic constriction injury of the sciatic nerve

BACKGROUND

Cutaneous peripheral neuropathies have been associated with changes of the sensory fiber innervation in the dermis and epidermis. These changes are mediated in part by the increase in local expression of trophic factors. Increase in target tissue nerve growth factor has been implicated in the promotion of peptidergic afferent and sympathetic efferent sprouting following nerve injury. The primary source of nerve growth factor is cells found in the target tissue, namely the skin. Recent evidence regarding the release and extracellular maturation of nerve growth factor indicate that it is produced in its precursor form and matured in the extracellular space. It is our hypothesis that the precursor form of nerve growth factor should be detectable in those cell types producing it. To date, limitations in available immunohistochemical tools have restricted efforts in obtaining an accurate distribution of nerve growth factor in the skin of naïve animals and those with neuropathic pain lesions. It is the objective of this study to delineate the distribution of the precursor form of nerve growth factor to those cell types expressing it, as well as to describe its distribution with respect to those nerve fibers responsive to it.

RESULTS

We observed a decrease in peptidergic fiber innervation at 1 week after the application of a chronic constriction injury (CCI) to the sciatic nerve, followed by a recovery, correlating with TrkA protein levels. ProNGF expression in CCI animals was significantly higher than in sham-operated controls from 1-4 weeks post-CCI. ProNGF immunoreactivity was increased in mast cells at 1 week post-CCI and, at later time points, in keratinocytes. P75 expression within the dermis and epidermis was significantly higher in CCI-operated animals than in controls and these changes were localized to neuronal and non-neuronal cell populations using specific markers for each.

CONCLUSIONS

We describe proNGF expression by non-neuronal cells over time after nerve injury as well as the association of NGF-responsive fibers to proNGF-expressing target tissues. ProNGF expression increases following nerve injury in those cell types previously suggested to express it.

Cyclosporine A induces nerve growth factor expression via activation of MAPK p38 and NFAT5

PURPOSE

We investigated the effects of cyclosporine A (CsA) on the mechanism of nerve growth factor (NGF) expression using a cultured human corneal epithelial cell line (HCECL).

METHODS

NGF transcription and production levels were assessed after treatment of cells with various concentrations of CsA. Activities of mitogen-activated protein kinase (MAPK), nuclear factor Kappa B (NF-κB), activator protein-1 (AP-1), and nuclear factor of activated T cells (NFATs) influenced by CsA were determined using a luciferase assay. The translocation activity of NFAT5 was assessed by confocal microscopy and Western immunoblotting after CsA treatment. Transcriptional activity of NGF was measured after pretreatment of cells with SB20429 (a p38 inhibitor) and NFAT5 small interfering RNA.

RESULTS

NGF was induced after treatment with CsA, but not dexamethasone, in the HCECL. NGF expression was mediated via p38 phosphorylation and NFAT5 activation. Transcriptional activities of NF-κB, AP-1, and NFAT1 were not stimulated by CsA; however, nuclear translocation of NFAT5 was markedly upregulated by CsA. CsA-induced NGF production was markedly decreased on inhibition of NFAT5 or SB20429.

CONCLUSIONS

CsA is a potent inducer of NGF in the HCECL. These results suggest that CsA mediates NGF expression through activation of p38 and NFAT5.

Increase of colonic mast cells in obstructed defecation and their relationship with enteric glia

BACKGROUND

Mast cells are involved in visceral hypersensitivity and motor activity of the gastrointestinal tract. However, there is almost no information concerning mast cells in constipated patients.

AIMS

The purpose of this study was to investigate mast cells distribution in all colonic layers in controls and severely constipated patients with obstructed defecation.

METHODS

Full-thickness specimens from colons of patients undergoing surgery for obstructed defecation due to refractoriness to other therapeutic interventions (n = 11), compared to controls, were obtained and the number of mast cells (evaluated by specific monoclonal antibodies) were counted in the whole viscus and in the various colonic segments (cecum, ascending, transverse, descending, and sigmoid).

RESULTS

Compared to controls, constipated patients had significantly higher numbers of mast cells, both as an overall number and in single colonic segments. This increase was especially evident in the mucosa and submucosa. Mast cells were homogeneously represented in the various segment of the large bowel, in both controls and patients. Degranulated mast cells were found to be close to enteric glial cells and glial filaments.

CONCLUSIONS

Colonic mast cells are increased in obstructed defecation patients. This might represent a vicariating mechanism to the impaired colonic propulsive activity of these patients.

[³H]serotonin release assay using antigen-stimulated rat peritoneal mast cells

The concentration of nerve growth factor (NGF) is elevated in a number of inflammatory and autoimmune states in conjunction with increased accumulation of mast cells. Mast cells, which are of hematopoietic lineage, and NGF appear to be involved in neuroimmune interactions and tissue inflammation. Mast cells themselves are capable of producing and responding to NGF. Here we describe a protocol for the isolation and culture of peritoneal-derived rat mast cells, together with a [(3)H]serotonin release assay which is useful in assessing the effects of antigens and neurotrophic factors on mast-cell activation.

Nerve growth factor derived from bronchial epithelium after chronic mite antigen exposure contributes to airway hyperresponsiveness by inducing hyperinnervation, and is inhibited by in vivo siRNA

BACKGROUND

Bronchial asthma is a chronic allergic airway inflammatory disease. Neurotrophins, including nerve growth factor (NGF), play an important role in the pathogenesis of asthma. However, the effects of NGF derived from epithelium on airway hyperresponsiveness (AHR) after antigen sensitization/exposure remain uncertain.

OBJECTIVE

In this study, we examined the role of NGF on AHR after chronic antigen exposure and the effect of inhibiting NGF by in vivo siRNA on AHR exacerbation.

METHODS

We generated chronic mouse models of bronchial asthma using house-dust mite antigen (Dermatophagoides pteronyssinus; Dp). NGF concentrations in bronchoalveolar lavage fluid (BALF), lung histopathology, hyperresponsiveness, and related neuronal peptides and cytokines in supernatants of lung homogenates were determined.

RESULTS

NGF in BALF was increased in a dose- and time-dependent manner, and was expressed primarily in bronchial epithelium. Nerve fibres and substance P-positive fibres were detected in subepithelium of Dp-sensitized and challenged mice over 4 weeks of mite antigen exposure. AHR was positively correlated with NGF concentration and nerve fibre innervation. AHR, modulation of innervation, and increased substance P were inhibited by in vivo administration of siRNA that targeted NGF, although the inhibition of NGF did not affect allergic inflammation and subepithelial fibrosis.

CONCLUSION AND CLINICAL RELEVANCE

These findings suggest that NGF derived from bronchial and alveolar epithelium plays an important role in AHR after chronic exposure to mite antigen. NGF inhibition could potentially manage bronchial asthma, including AHR.

Overview on the pathomechanisms of allergic rhinitis

Allergic rhinitis a chronic inflammatory disease of the upper airways that has a major impact on the quality of life of patients and is a socio-economic burden. Understanding the underlying immune mechanisms is central to developing better and more targeted therapies. The inflammatory response in the nasal mucosa includes an immediate IgE-mediated mast cell response as well as a latephase response characterized by recruitment of eosinophils, basophils, and T cells expressing Th2 cytokines including interleukin (IL)-4, a switch factor for IgE synthesis, and IL-5, an eosinophil growth factor and on-going allergic inflammation. Recent advances have suggested new pathways like local synthesis of IgE, the IgE-IgE receptor mast cell cascade in on-going allergic inflammation and the epithelial expression of cytokines that regulate Th2 cytokine responses (i.e., thymic stromal lymphopoietin, IL-25, and IL-33). In this review, we briefly review the conventional pathways in the pathophysiology of allergic rhinitis and then elaborate on the recent advances in the pathophysiology of allergic rhinitis. An improved understanding of the immune mechanisms of allergic rhinitis can provide a better insight on novel therapeutic targets.

Involvement of mast cells in a mouse model of postoperative pain

Recent studies have indicated that nearly half of all surgical patients still have inadequate pain relief; therefore, it is becoming increasingly more important to understand the mechanisms involved in postoperative pain in order to be better treated. Previous studies have shown that incisions can cause mast cell degranulation. Thus, the aim of this study was to investigate the involvement of mast cells in a model of postoperative pain in mice. The depletion of mast cell mediators produced by pre-treatment with compound 48/80 (intraplantar (i.pl.)) widely (98 ± 23% of inhibition) and extensively (up to 96 h) prevented postoperative nociception and reduced histamine and serotonin levels (88 ± 4% and 68 ± 10%, respectively) in operated tissue. Furthermore, plantar surgery produced immense mast cell degranulation, as assessed by histology and confirmed by the increased levels of serotonin (three-fold higher) and histamine (fifteen-fold higher) in the perfused tissue, 1h after surgery. Accordingly, pre-treatment with the mast cell membrane stabilizer cromoglycate (200 μg/paw, i.pl.) prevented mechanical allodynia (inhibition of 96 ± 21%) and an increase in histamine (44 ± 10% of inhibition) and serotonin (73 ± 5% of inhibition) levels induced by plantar surgery. Finally, local treatment with H(1) (promethazine, 100 μg/paw, i.pl.), 5-HT(3) (ondansetron, 10 μg/paw, i.pl.) or 5-HT(2A) (ketanserin, 5 μg/paw, i.pl.) receptor antagonists partially decreased postoperative nociception in mice, but when co-administered together it completely reversed the mechanical allodynia in operated mice. Thus, mast cell activation mechanisms are interesting targets for the development of novel therapies to treat postoperative pain.

Colonic mast cells in controls and slow transit constipation patients

BACKGROUND

There is recent evidence that mast cells may play important roles in the gut, especially concerning visceral hypersensitivity and motor activity. However, most data are only available for clinical conditions characterised by diarrhoea, where MC have chiefly investigated in the mucosal layer of the colon and there is almost no information concerning constipation.

AIM

To investigate mast cells distribution in all colonic layers in controls and severely constipated patients.

METHODS

Full-thickness specimens from colons of patients undergoing surgery for slow transit constipation (n=29), compared with controls, were obtained and the number of mast cells (evaluated by specific monoclonal antibodies) counted as a whole and in single colonic segments (caecum, ascending, transverse, descending and sigmoid).

RESULTS

Compared with controls, constipated patients revealed significantly higher number of mast cells, both as overall number and in single colonic segments. The distribution of mast cells resulted fairly homogeneous in the various segment of the large bowel, in both controls and patients, and no significant difference in the percentage of degranulated cells was found between groups.

CONCLUSIONS

Colonic mast cells display a homogeneous distribution within the viscus. This cell population is shown to increase in severely constipated patients, which might represent a mechanism trying to compensate for the impaired propulsive activity of these patients.

Antagonism of nerve growth factor-TrkA signaling and the relief of pain

Nerve growth factor (NGF) was originally discovered as a neurotrophic factor essential for the survival of sensory and sympathetic neurons during development. However, in the adult NGF has been found to play an important role in nociceptor sensitization after tissue injury. The authors outline mechanisms by which NGF activation of its cognate receptor, tropomyosin-related kinase A receptor, regulates a host of ion channels, receptors, and signaling molecules to enhance acute and chronic pain. The authors also document that peripherally restricted antagonism of NGF-tropomyosin-related kinase A receptor signaling is effective for controlling human pain while appearing to maintain normal nociceptor function. Understanding whether there are any unexpected adverse events and how humans may change their behavior and use of the injured/degenerating tissue after significant pain relief without sedation will be required to fully appreciate the patient populations that may benefit from these therapies targeting NGF.

Need for a comprehensive medical approach to the neuro-immuno-gastroenterology of irritable bowel syndrome

Irritable bowel syndrome (IBS) is defined by the Rome III criteria as symptoms of recurrent abdominal pain or discomfort with the onset of a marked change in bowel habits with no evidence of an inflammatory, anatomic, metabolic, or neoplastic process. As such, many clinicians regard IBS as a central nervous system problem of altered pain perception. Here, we review the recent literature and discuss the evidence that supports an organic based model, which views IBS as a complex, heterogeneous, inter-dependent, and multi-variable inflammatory process along the neuronal-gut axis. We delineate the organic pathophysiology of IBS, demonstrate the role of inflammation in IBS, review the possible differences between adult and pediatric IBS, discuss the merits of a comprehensive treatment model as taught by the Institute of Functional Medicine, and describe the potential for future research for this syndrome.

Repeated muscle injury as a presumptive trigger for chronic masticatory muscle pain

skeletal muscles sustain a significant loss of maximal contractile force after injury, but terminally damaged fibers can eventually be replaced by the growth of new muscle (regeneration), with full restoration of contractile force over time. After a second injury, limb muscles exhibit a smaller reduction in maximal force and reduced inflammation compared with that after the initial injury (i.e., repeated bout effect). In contrast, masticatory muscles exhibit diminished regeneration and persistent fibrosis, after a single injury; following a second injury, plasma extravasation is greater than after a single injury and maximal force is decreased more than after the initial injury. Thus, masticatory muscles do not exhibit a repeated bout effect and are instead increasingly damaged by repeated injury. We propose that the impaired ability of masticatory muscles to regenerate contributes to chronic muscle pain by leading to an accumulation of tissue damage, fibrosis, and a persistent elevation and prolonged membrane translocation of nociceptive channels such as P2X(3) as well as enhanced expression of neuropeptides including CGRP within primary afferent neurons. These transformations prime primary afferent neurons for enhanced responsiveness upon subsequent injury thus triggering and/or exacerbating chronic muscle pain.

Potential targets for intervention in radiation-induced heart disease

Radiotherapy of thoracic and chest wall tumors, if all or part of the heart was included in the radiation field, can lead to radiation-induced heart disease (RIHD), a late and potentially severe side effect. RIHD presents clinically several years after irradiation and manifestations include accelerated atherosclerosis, pericardial and myocardial fibrosis, conduction abnormalities, and injury to cardiac valves. The pathogenesis of RIHD is largely unknown, and a treatment is not available. Hence, ongoing pre-clinical studies aim to elucidate molecular and cellular mechanisms of RIHD. Here, an overview of recent pre-clinical studies is given, and based on the results of these studies, potential targets for intervention in RIHD are discussed.

Breast cancer-induced bone remodeling, skeletal pain, and sprouting of sensory nerve fibers

Breast cancer metastasis to bone is frequently accompanied by pain. What remains unclear is why this pain tends to become more severe and difficult to control with disease progression. Here we test the hypothesis that with disease progression, sensory nerve fibers that innervate the breast cancer bearing bone undergo a pathological sprouting and reorganization, which in other nonmalignant pathologies has been shown to generate and maintain chronic pain. Injection of human breast cancer cells (MDA-MB-231-BO) into the femoral intramedullary space of female athymic nude mice induces sprouting of calcitonin gene-related peptide (CGRP(+)) sensory nerve fibers. Nearly all CGRP(+) nerve fibers that undergo sprouting also coexpress tropomyosin receptor kinase A (TrkA(+)) and growth-associated protein-43 (GAP43(+)). This ectopic sprouting occurs in periosteal sensory nerve fibers that are in close proximity to breast cancer cells, tumor-associated stromal cells, and remodeled cortical bone. Therapeutic treatment with an antibody that sequesters nerve growth factor (NGF), administered when the pain and bone remodeling were first observed, blocks this ectopic sprouting and attenuates cancer pain. The present data suggest that the breast cancer cells and tumor-associated stromal cells express and release NGF, which drives bone pain and the pathological reorganization of nearby CGRP(+)/TrkA(+)/GAP43(+) sensory nerve fibers.

PERSPECTIVE

Therapies that block breast cancer pain by reducing the tumor-induced pathological sprouting and reorganization of sensory nerve fibers may provide insight into the evolving mechanisms that drive breast cancer pain and lead to more effective therapies for attenuating this chronic pain state.

Enhanced nerve-mast cell interaction by a neuronal short isoform of cell adhesion molecule-1

Close apposition of nerve and mast cells is viewed as a functional unit of neuro-immune mechanisms, and it is sustained by trans-homophilic binding of cell adhesion molecule-1 (CADM1), an Ig superfamily member. Cerebral nerve-mast cell interaction might be developmentally modulated, because the alternative splicing pattern of four (a-d) types of CADM1 transcripts drastically changed during development of the mouse cerebrum: developing cerebrums expressed CADM1b and CADM1c exclusively, while mature cerebrums expressed CADM1d additionally and predominantly. To probe how individual isoforms are involved in nerve-mast cell interaction, Neuro2a neuroblastoma cells that express CADM1c endogenously were modified to express additionally either CADM1b (Neuro2a-CADM1b) or CADM1d (Neuro2a-CADM1d), and they were cocultured with mouse bone marrow-derived mast cells (BMMCs) and BMMC-derived cell line IC-2 cells, both of which expressed CADM1c. BMMCs were found to adhere to Neuro2a-CADM1d neurites more firmly than to Neuro2a-CADM1b neurites when the adhesive strengths were estimated from the femtosecond laser-induced impulsive forces minimally required for detaching BMMCs. GFP-tagging and crosslinking experiments revealed that the firmer adhesion site consisted of an assembly of CADM1d cis-homodimers. When Neuro2a cells were specifically activated by histamine, intracellular Ca(2+) concentration was increased in 63 and 38% of CADM1c-expressing IC-2 cells that attached to the CADM1d assembly site and elsewhere, respectively. These results indicate that CADM1d is a specific neuronal isoform that enhances nerve-mast cell interaction, and they suggest that nerve-mast cell interaction may be reinforced as the brain grows mature because CADM1d becomes predominant.

Respiratory syncytial virus prevention and therapy: past, present, and future

Respiratory syncytial virus (RSV) is the most common respiratory pathogen in infants and young children worldwide. More than 50 years after its discovery, and despite relentless attempts to identify pharmacological therapies to improve the clinical course and outcomes of this disease, the most effective therapy remains supportive care. Although the quest for a safe and effective vaccine remains unsuccessful, pediatricians practicing during the past decade have been able to protect at least the more vulnerable patients with safe and effective passive prophylaxis. This review summarizes the history, microbiology, epidemiology, pathophysiology, and clinical manifestations of this infection in order to provide the reader with the background information necessary to fully appreciate the many challenges presented by the clinical management of young children with bronchiolitis. The last part of this article attempts an evidence-based review of the pharmacologic strategies currently available and those being evaluated, intentionally omitting highly experimental approaches not yet tested in clinical trials and, therefore, not likely to become available in the foreseeable future.

Targeted downregulation of N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase significantly mitigates chondroitin sulfate proteoglycan-mediated inhibition

Chondroitin sulfate-4,6 (CS-E) glycosaminoglycan (GAG) upregulation in astroglial scars is a major contributor to chondroitin sulfate proteoglycan (CSPG)-mediated inhibition [Gilbert et al. (2005) Mol Cell Neurosci 29:545–558]. However, the role of N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase (GalNAc4S6ST) catalyzed sulfation of CS-E, and its contribution to CSPG-mediated inhibition of CNS regeneration remains to be fully elucidated. Here, we used in situ hybridization to show localized upregulation of GalNAc4S6ST mRNA after CNS injury. Using in vitro spot assays with immobilized CS-E, we demonstrate dose-dependent inhibition of rat embryonic day 18 (E18) cortical neurons. To determine whether selective downregulation of CS-E affected the overall inhibitory character of extracellular matrix produced by reactive astrocytes, single [against (chondroitin 4) sulfotransferase 11 (C4ST1) or GalNAc4S6ST mRNA] or double [against C4ST1 and GalNAc4S6ST mRNA] siRNA treatments were conducted and assayed using quantitative real-time polymerase chain reaction and high-performance liquid chromatography to confirm the specific downregulation of CS-4S GAG (CS-A) and CS-E. Spot and Bonhoeffer stripe assays using astrocyte-conditioned media from siRNA-treated rat astrocytes showed a significant decrease in inhibition of neuronal attachment and neurite extensions when compared with untreated and TGF-treated astrocytes. These findings reveal that selective attenuation of CS-E via siRNA targeting of GalNAc4S6ST significantly mitigates CSPG-mediated inhibition of neurons, potentially offering a novel intervention strategy for CNS injury.

Biological implications of preformed mast cell mediators

Mast cells store an impressive array of preformed compounds (mediators) in their secretory granules. When mast cells degranulate, these are released and have a profound impact on any condition in which mast cell degranulation occurs. The preformed mast cell mediators include well-known substances such as histamine, proteoglycans, proteases, and preformed cytokines, as well as several recently identified compounds. Mast cells have recently been implicated in a large number of novel pathological settings in addition to their well-established contribution to allergic reactions, and there is consequently a large current interest in the molecular mechanisms by which mast cells act in the context of a given condition. In many cases, preformed mast cell mediators have been shown to account for functions ascribed to mast cells, and these compounds are hence emerging as major players in numerous pathologies. In this review we summarize the current knowledge of preformed mast cell mediators.

Palmitoylethanolamide reduces granuloma-induced hyperalgesia by modulation of mast cell activation in rats

The aim of this study was to obtain evidences of a possible analgesic role for palmitoylethanolamide (PEA) in chronic granulomatous inflammation sustained by mast cell (MC) activation in rats at 96 hours. PEA (200-400-800 μg/mL), locally administered at time 0, reduced in a concentration-dependent manner the expression and release of NGF in comparison with saline-treated controls. PEA prevented nerve formation and sprouting, as shown by histological analysis, reduced mechanical allodynia, evaluated by Von Frey filaments, and inhibited dorsal root ganglia activation. These results were supported by the evidence that MCs in granuloma were mainly degranulated and closely localized near nerve fibres and PEA significantly reduced MC degranulation and nerves fibre formation. These findings are the first evidence that PEA, by the modulation of MC activation, controls pain perception in an animal model of chronic inflammation, suggesting its potential use for the treatment of all those painful conditions in which MC activation is an initial key step.

Effects of endogenous substance P expression on degranulation in RBL-2H3 cells

OBJECTIVE AND DESIGN

To determine whether RBL-2H3 cells have endogenous substance P (SP) expression under immunoglobulin E (IgE)-activated and inactivated conditions, and to ascertain the function of endogenous SP in the antigen-induced degranulation of RBL-2H3 cells.

MATERIALS AND METHODS

SP mRNA and protein expression in both inactivated and 2,4-dinitrophenol (DNP)-specific IgE-activated RBL-2H3 cells were assessed by real-time PCR and immunofluorescence, respectively. Following activation with DNP-specific IgE, the degranulation of RBL-2H3 cells in response to DNP-bovine serum albumin (BSA), with and without endogenous SP expression, was assessed by monitoring the release of the granular enzyme β-hexosaminidase.

RESULTS

Endogenous SP mRNA and peptide expression increased in activated RBL-2H3 cells, compared with inactivated RBL-2H3 cells. The small hairpin RNA (shRNA)-mediated knockdown of endogenous SP reduced the degranulation ability of RBL-2H3 cells.

CONCLUSIONS

Activated RBL-2H3 cells express endogenous SP which plays a role in antigen-induced degranulation.

Preclinical research into basic mechanisms of radiation-induced heart disease

Radiation-induced heart disease (RIHD) is a potentially severe side effect of radiotherapy of thoracic and chest wall tumors if all or part of the heart was included in the radiation field. RIHD presents clinically several years after irradiation and manifestations include accelerated atherosclerosis, pericardial and myocardial fibrosis, conduction abnormalities, and injury to cardiac valves. There is no method to prevent or reverse these injuries when the heart is exposed to ionizing radiation. This paper presents an overview of recent studies that address the role of microvascular injury, endothelial dysfunction, mast cells, and the renin angiotensin system in animal models of cardiac radiation injury. These insights into the basic mechanisms of RIHD may lead to the identification of targets for intervention in this late radiotherapy side effect.

Airway mast cells in a rhesus model of childhood allergic airways disease

Asthma is a leading cause of morbidity in children. Risk factors include chronic exposure to allergens and air pollution. While chronically activated mast cells contribute to the pathophysiology of asthma in part through their proteases such as chymase and tryptase, previous studies of airway mast cell abundance and distribution in asthmatics have been inconsistent. To determine whether repeated episodic exposures to environmental pollutants during postnatal lung development alter airway mast cell abundance and distribution, we exposed infant rhesus monkeys to a known human allergen, house dust mite antigen (HDMA), and/or a known environmental pollutant, ozone (O(3)), and quantitatively compared the abundance of tryptase- or chymase-positive mast cells in three airway levels. Mast cells are resident in multiple compartments of the airway wall in infant rhesus monkeys raised from birth in filtered air. Tryptase- and chymase-positive cells were most abundant in trachea and least in terminal bronchioles. The majority of tryptase-positive and almost all chymase-positive cells were in extracellular matrix and smooth muscle bundles. Chronic exposure to HDMA elevated the abundance of both tryptase- and chymase-positive cells in the trachea and intrapulmonary bronchi. Neither exposure to O(3) nor HDMA + O(3) increased mast cell accumulations in the airway wall. We conclude that during postnatal airway development (1) mast cells are a resident airway cell population even in the absence of toxic air contaminants; (2) aeroallergen exposure alters large airway mast cell distribution and abundance, increasing chymase-positive mast cells; and (3) this response is attenuated by exposure to oxidant air pollutants.

Facioscapulohumeral muscular dystrophy: do neurotrophins play a role?

Although the molecular defect of facioscapulohumeral muscular dystrophy (FSHD) is well established and involves the contraction of the polymorphic 3.3 kb D4Z4 repeat on the subtelomeric region of chromosome 4q35, the pathologic effects of this deletion remain largely unknown. As a consequence, no specific treatment for FSHD is at present available. Thus, there is the need to explore new areas in an attempt to better characterize pathophysiological alterations in FSHD that might be useful for managing the disease. Neurotrophins (nerve growth factor, brain-derived neurotrophic factor, neurotrophin-3, and neurotrophin-4/5) are a class of proteins involved in the development, maintenance, and function of neurons of the peripheral and central nervous systems. In addition, neurotrophins and their RNAs are expressed in muscle, where they have a role in development and regeneration. In this article we put together the experimental evidence that indicates neurotrophins might be involved in the pathophysiology of FSHD and discuss the possible implications of this assumption.

Adrenergic stimulation mediates visceral hypersensitivity to colorectal distension following heterotypic chronic stress

BACKGROUND & AIMS

Chronic stress exacerbates or causes relapse of symptoms such as abdominal pain and cramping in patients with irritable bowel syndrome. We investigated whether chronic stress increases plasma norepinephrine and sensitizes colon-specific dorsal root ganglion (DRG) neurons by increasing expression of nerve growth factor (NGF) in the colon wall.

METHODS

Heterotypic chronic stress (HeCS) was applied to male Wistar rats and neurologic and molecular responses were analyzed. Tissues were analyzed for NGF expression.

RESULTS

HeCS significantly increased visceromoter response to colorectal distension; expression of NGF increased in colonic muscularis externa and mucosa/submucosa. Rheobase decreased, resting membrane potential was depolarized, and electrogenesis of action potentials increased in colon-specific thoracolumbar DRG neurons. Luminal administration of resiniferatoxin in distal colon, systemic administration of anti-NGF antibody, or inhibition of the NGF receptor trkA by k252a or antisense oligonucleotides in thoracolumbar DRG blocked the chronic stress-induced visceral hypersensitivity to colorectal distension. Blockade of alpha1/alpha2- and beta1/beta2-adrenergic receptors prevented the stress-induced visceral hypersensitivity and increased expression of NGF in the colon wall. HeCS did not induce any inflammatory response in the colon wall.

CONCLUSIONS

The peripheral stress mediator norepinephrine induces visceral hypersensitivity to colorectal distension in response to HeCS by increasing the expression of NGF in the colon wall, which sensitizes primary afferents in the absence of an inflammatory response.

Metalloproteinase MT5-MMP is an essential modulator of neuro-immune interactions in thermal pain stimulation

Peripheral interactions between nociceptive fibers and mast cells contribute to inflammatory pain, but little is known about mechanisms mediating neuro-immune communication. Here we show that metalloproteinase MT5-MMP (MMP-24) is an essential mediator of peripheral thermal nociception and inflammatory hyperalgesia. We report that MT5-MMP is expressed by CGRP-containing peptidergic nociceptors in dorsal root ganglia and that Mmp24-deficient mice display enhanced sensitivity to noxious thermal stimuli under basal conditions. Consistently, mutant peptidergic sensory neurons hyperinnervate the skin, a phenotype that correlates with changes in the regulated cleavage of the cell-cell adhesion molecule N-cadherin. In contrast to basal nociception, Mmp24(-/-) mice do not develop thermal hyperalgesia during inflammation, a phenotype that appears associated with alterations in N-cadherin-mediated cell-cell interactions between mast cells and sensory fibers. Collectively, our findings demonstrate an essential role of MT5-MMP in the development of dermal neuro-immune synapses and suggest that this metalloproteinase may be a target for pain control.

Prenatal and early, but not late, postnatal exposure of mice to sidestream tobacco smoke increases airway hyperresponsiveness later in life

BACKGROUND

Cigarette smoke exposure in utero and during early postnatal development increases the incidence of asthma and airway hyperresponsiveness (AHR) later in life, suggesting that a possible critical period of developmental sensitivity exists in the prenatal and early postnatal periods.

OBJECTIVE

We investigated mechanisms of susceptibility during critical developmental periods to sidestream smoke (SS) exposure and evaluated the possible effects of SS on neural responses.

METHODS

We exposed three different age groups of mice to either SS or filtered air (FA) for 10 consecutive days beginning on gestation day (GD) 7 by maternal exposure or beginning on postnatal day (PND) 2 or PND21 by direct inhalation. Lung function, airway substance P (SP) innervation, and nerve growth factor (NGF) levels in broncho alveolar lavage fluid were measured after a single SS exposure on PND59.

RESULTS

Methacholine (MCh) dose response for lung resistance (R(L)) was significantly elevated, and dynamic pulmonary compliance (C(dyn)) was significantly decreased, in the GD7 and PND2 SS exposure groups compared with the FA groups after SS exposure on PND59. At the same time points, the percent area of SP nerve fibers in tracheal smooth muscle and the levels of NGF were significantly elevated. MCh dose-response curves for R(L) and C(dyn), SP nerve fiber density, and the level of NGF were not significantly changed in the PND21 exposure group after SS exposure on PND59.

CONCLUSIONS

These results suggest that a critical period of susceptibility to SS exposure exists in the prenatal and early postnatal period of development in mice that results in increased SP innervation, increased NGF levels in the airway, and enhanced MCh AHR later in life.

Chronic eosinophilic pneumonia associated with neurofibromatosis type 1: an unusual complication

Neurofibromatosis type 1 (formerly known as von Recklinghausen's disease) is an autosomal dominant disorder, which results from the proliferation of the neural crest cells, thus affecting any organ system. Several pulmonary manifestations have hitherto been reported, including chest wall deformities, diffuse lung disease, thoracic neoplasms, pulmonary arterial hypertension, central hypoventilation, diaphragmatic paralysis and meningocele. However, eosinophilic lung disorders have not been described. An unusual case of chronic eosinophilic pneumonia in a patient with neurofibromatosis type 1, is reported herein. He had a propitious outcome, following corticosteroid treatment. This is the first well-documented case of chronic eosinophilic pneumonia and neurofibromatosis type 1 in the same patient. These clinical entities might share common pathogenic mechanisms, as suggested by the present study, that could explain their co-existence.

Medical treatment for rectovaginal endometriosis: what is the evidence?

BACKGROUND

Rectovaginal endometriosis usually causes distressing pain. Surgical treatment may be effective but is associated with a high risk of morbidity and major complications. Information on the effect of medical alternatives for pain relief in this condition is scarce.

METHODS

A comprehensive literature search was conducted to identify all the English language published observational and randomized studies evaluating the efficacy of medical treatments on pain associated with rectovaginal endometriosis. A combination of keywords was used to identify relevant citations in PubMed, MEDLINE and EMBASE.

RESULTS

A total of 217 cases of medically treated rectovaginal endometriosis were found; 68 in five observational, non-comparative studies, 59 in one patient preference cohort study, and 90 in a randomized controlled trial. An aromatase inhibitor was used in two of the non-comparative studies, vaginal danazol in one, a GnRH agonist in one, and an intrauterine progestin in one. Two estrogen-progestin combinations used transvaginally or transdermally were evaluated in the patient preference study, whereas an oral progestin and an estrogen-progestin combination were compared in the randomized controlled trial. With the exception of an aromatase inhibitor used alone, the antalgic effect of the considered medical therapies was high for the entire treatment period (from 6 to 12 months), with 60-90% of patients reporting considerable reduction or complete relief from pain symptoms.

CONCLUSIONS

Despite problems in interpretation of data, the effect of medical treatment in terms of pain relief in women with rectovaginal endometriosis appear substantial.

Expression of Placental Neurotrophin-3 (NT-3) in Physiological Pregnancy, Preeclampsia and Chorioamnionitis

Neurotrophic factors are a group of proteins that act as paracrine and autocrine growth factors. They are involved in the regulation of morphogenesis and development of several tissues. The present study aims to evaluate, for the first time, the expression of Neurotrophin-3 in the human placenta during normal pregnancy and in preeclampsia and chorioamnionitis. Neurotrophin-3 mRNA, assessed by RT-PCR analysis in six term placentas, were observed in all the specimens examined. Neurotrophin-3 protein expression and tissue distribution was evaluated by immunohistochemistry in placenta samples from uncomplicated first trimester (n = 5) and term (n = 5) pregnancies as well as in specimens from preeclampsia (n = 5) and chorioamnionitis (n = 5). In first trimester specimens, strong immunoreactivity was present in villous stromal cells, in the cyto- and syncytiotrophoblast, in decidua cells and in endometrial glands. Third trimester specimens showed prominent immunostaining in cyto- and syncytiotrophoblast cells, in decidua cells and in the amniotic membranes. Villous stromal cells were weakly stained. Similar protein localization was observed in placentas with preeclampsia and chorioamnionitis. In the latter, however, positive villous stromal cells increased in number and in staining intensity when compared with controls and preeclampsia (p < 0.001). The roles of Neurotrophin-3 in pregnancy are presently unknown. A regulatory function on placenta and foetal brain development and maternal inflammatory response may be hypothesized.

Nerve growth factor in rheumatic diseases

OBJECTIVES

The nervous system modulates the immune response in many autoimmune syndromes by neurogenic inflammation. One of the pivotal mediators is nerve growth factor (NGF), which is known for its effects on neuronal survival and growth. There is considerable evidence that NGF acts as an important mediator of many immune responses. This article reviews the role of NGF in rheumatic diseases and strategies for potential therapeutic interventions.

METHODS

We conducted a database search using Medline and Medpilot. Eight hundred abstracts containing the keyword NGF and 1 of the following terms were reviewed: arthritis, neurogenic inflammation, rheumatoid arthritis, osteoarthritis, collagen arthritis, arteritis, psoriasis, psoriatic arthritis, Sjogren syndrome, systemic lupus erythematosus, gout, osteoporosis, lower back pain, lumbar disc herniation, nerve root compression, spondyloarthritis, spondylarthropathy, algoneurodystrophy, fibromyalgia, Kawasaki syndrome, polyarteritis nodosa, cytokine, vasculitis, pain, therapy, and antagonist. Articles were analyzed based on relevance and content. Most clinical trials and studies with human specimens were included. Studies with experimental animal models were selected if they contained relevant data.

RESULTS

NGF is overexpressed in many inflammatory and degenerative rheumatic diseases. Concentrations differ to some extent and sometimes even show contradictory results. NGF is found in serum, synovial fluid, and cerebrospinal fluid, and tissue specimens. NGF concentrations can be correlated with the extent of inflammation and/or clinical activity in many conditions. In rheumatoid arthritis, NGF levels are significantly higher as compared with osteoarthritis.

CONCLUSIONS

NGF is a significant mediator and modulator of inflammation. NGF sometimes shows detrimental and sometimes regenerative activity. These findings indicate potential therapeutic interventions using either NGF antagonists or recombinant NGF.

High abundances of neurotrophin 3 in atopic dermatitis mast cell

Background

Neurotrophin 3 (NT-3) is a member of the neurotrophin family, a group of related proteins that are known to regulate neuro-immune interactions in allergic diseases. Their cellular sources and role in the recruitment of mast cell precursors in atopic dermatitis have not been characterized in detail so far.

Objective

Characterize NT-3 on a transcriptional and translational level in individuals with atopic dermatitis with special focus on mast cells.

Methods

To meet this objective NT-3 levels in the serum of AD patients were measured, the effect of NT-3 on keratinocytes was evaluated and the gene expression and regulation assessed using ELISA, immunohistochemistry and RNA quantification.

Results

Systemic levels of NT-3 were found to be higher in individuals with AD as compared to healthy controls. A distinct genetic expression was found in the various cells of the skin. In lesional mast cells of individuals with atopic dermatitis an increased amount of NT-3 was apparent. Functional in vitro experiments demonstrated that NT-3 stimulation led to a suppression of IL-8 secretion by HaCat cells.

Conclusion

These findings could imply a role for NT-3 in the pathogenesis of allergic skin diseases.

Hirschsprung’s disease: Is there a relationship between mast cells and nerve fibers?

AIM: To define the topography of mast cells and their numbers in cases of Hirschsprung’s disease (HD) and non-HD, assess neural hypertrophy using imaging software and to study the relationship between mast cells and nerve fibers.

METHODS: HE stained sections of 32 cases of chronic constipation in the age group of 0-14 years were reviewed for ganglion cells. AChE staining was performed on frozen sections of colonic and rectal biopsies. Based on their findings cases were divided into HD and non-HD and mast cells stained by toluidine blue were evaluated. Image analysis by computerized software was applied to S-100 stained sections for assessment of neural hypertrophy.

RESULTS: Difference between number of mast cells in HD group (mean = 36.44) and in non-HD group (mean = 14.79) was statistically significant. Image analysis morphometry on S-100 stained sections served as a useful adjunct. The difference between number, size, and perimeter of the nerve fibers between HD and non-HD group was statistically significant.

CONCLUSION: Mast cells are significantly increased in HD and their base line values are much higher in Indian children than that reported in Western literature. Their role in HD needs further research. Morphometry of S-100 stained nerve fibers is a useful adjunct to conventional methods for diagnosis of HD.

Expression profile of nerve growth factor after muscle incision in the rat

BACKGROUND

Previous studies have demonstrated that nerve growth factor (NGF) is an important mediator of pathologic pain. Many studies have focused on cutaneous mechanisms for NGF-induced hyperalgesia; few have examined its contribution in deeper tissues like muscle. This study examined pain behaviors and the expression of NGF in incised hind paw flexor digitorum brevis muscle.

METHODS

Adult Sprague-Dawley rats were pretreated with anti-NGF peptibody and underwent skin or skin plus deep fascia and muscle incision. Guarding pain behaviors were measured. Muscle NGF messenger RNA (mRNA) was measured by reverse-transcriptase polymerase chain reaction. Changes in NGF protein expression were measured using Western blot, enzyme-linked immunosorbent assay, and immunohistochemistry. In situ hybridization for NGF mRNA was also performed.

RESULTS

Pretreatment with anti-NGF peptibody (100 mg/kg) decreased the guarding behavior caused by deep fascia and muscle incision. Muscle NGF mRNA increased abruptly 2 h after incision and was the same as control by postoperative day 1. NGF protein increased from 4 h after incision and was sustained for several days. NGF was localized in many calcitonin gene-related peptide-positive axons, few N52-positive axons, but not isolectin B4-positive axons in incised muscle. The sources of NGF mRNA included keratinocytes in epidermis and fibroblasts in deeper tissues.

CONCLUSION

Fibroblasts adjacent to the injury are sources of NGF in incised muscle. NGF is upregulated by incision of muscle and contributes to guarding pain behavior.

Basic and clinical aspects of gastrointestinal pain

The gastrointestinal (GI) tract is a system of organs within multicellular animals which facilitates the ingestion, digestion, and absorption of food with subsequent defecation of waste. A complex arrangement of nerves and ancillary cells contributes to the sensorimotor apparatus required to subserve such essential functions that are with the exception of the extreme upper and lower ends of the GI tract normally subconscious. However, it also has the potential to provide conscious awareness of injury. Although this function can be protective, when dysregulated, particularly on a chronic basis, the same system can lead to considerable morbidity. The anatomical and molecular basis of gastrointestinal nociception, conditions associated with chronic unexplained visceral pain, and developments in treatment are presented in this review.