Carla Cirillo

Increased mucosal nitric oxide production in ulcerative colitis is mediated in part by the enteroglial‐derived S100B protein

Abstract  In the central nervous system glial‐derived S100B protein has been associated with inflammation via nitric oxide (NO) production. As the role of enteroglial cells in inflammatory bowel disease has been poorly investigated in humans, we evaluated the association of S100B and NO production in ulcerative colitis (UC). S100B mRNA and protein expression, inducible NO synthase (iNOS) expression, and NO production were evaluated in rectal biopsies from 30 controls and 35 UC patients. To verify the correlation between S100B and NO production, biopsies were exposed to S100B, in the presence or absence of specific receptor for advanced glycation end‐products (RAGE) blocking antibody, to measure iNOS expression and nitrite production. S100B and iNOS expression were evaluated after incubation of biopsies with lipopolysaccharides (LPS) + interferon‐gamma (IFN‐γ) in the presence of anti‐RAGE or anti‐S100B antibodies or budesonide. S100B mRNA and protein expression, iNOS expression and NO production were significantly higher in the rectal mucosa of patients compared to that of controls. Exogenous S100B induced a significant increase in both iNOS expression and NO production in controls and UC patients; this increase was inhibited by specific anti‐RAGE blocking antibody. Incubation with LPS + IFN‐γ induced a significant increase in S100B mRNA and protein expression, together with increased iNOS expression and NO production. LPS + IFN‐γ‐induced S100B up‐regulation was not affected by budesonide, while iNOS expression and NO production were significantly inhibited by both specific anti‐RAGE and anti‐S100B blocking antibodies. Enteroglial‐derived S100B up‐regulation in UC participates in NO production, involving RAGE in a steroid insensitive pathway.

Enteroglial-derived S100B protein integrates bacteria-induced Toll-like receptor signalling in human enteric glial cells

Objective Enteric glial cells (EGC) have been suggested to participate in host–bacteria cross-talk, playing a protective role within the gut. The way EGC interact with microorganisms is still poorly understood. We aimed to evaluate whether: EGC participate in host–bacteria interaction; S100B and Toll-like receptor (TLR) signalling converge in a common pathway leading to nitric oxide (NO) production. Design Primary cultures of human EGC were exposed to pathogenic (enteroinvasive Escherichia coli; EIEC) and probiotic (Lactobacillus paracasei F19) bacteria. Cell activation was assessed by evaluating the expression of cFos and major histocompatibility complex (MHC) class II molecules. TLR expression in EGC was evaluated at both baseline and after exposure to bacteria by real-time PCR, fluorescence microscopy and western blot analysis. S100B expression and NO release from EGC, following exposure to bacteria, were measured in the presence or absence of specific TLR and S100B pathway inhibitors. Results EIEC activated EGC by inducing the expression of cFos and MHC II. EGC expressed TLR at baseline. Pathogens and probiotics differentially modulated TLR expression in EGC. Pathogens, but not probiotics, significantly induced S100B protein overexpression and NO release from EGC. Pretreatment with specific inhibitors of TLR and S100B pathways abolished bacterial-induced NO release from EGC. Conclusions Human EGC interact with bacteria and discriminate between pathogens and probiotics via a different TLR expression and NO production. In EGC, NO release is impaired in the presence of specific inhibitors of the TLR and S100B pathways, suggesting the presence of a novel common pathway involving both TLR stimulation and S100B protein upregulation.

Cannabidiol Reduces Intestinal Inflammation through the Control of Neuroimmune Axis

Enteric glial cells (EGC) actively mediate acute and chronic inflammation in the gut; EGC proliferate and release neurotrophins, growth factors, and pro-inflammatory cytokines which, in turn, may amplify the immune response, representing a very important link between the nervous and immune systems in the intestine. Cannabidiol (CBD) is an interesting compound because of its ability to control reactive gliosis in the CNS, without any unwanted psychotropic effects. Therefore the rationale of our study was to investigate the effect of CBD on intestinal biopsies from patients with ulcerative colitis (UC) and from intestinal segments of mice with LPS-induced intestinal inflammation. CBD markedly counteracted reactive enteric gliosis in LPS-mice trough the massive reduction of astroglial signalling neurotrophin S100B. Histological, biochemical and immunohistochemical data demonstrated that S100B decrease was associated with a considerable decrease in mast cell and macrophages in the intestine of LPS-treated mice after CBD treatment. Moreover the treatment of LPS-mice with CBD reduced TNF-α expression and the presence of cleaved caspase-3. Similar results were obtained in ex vivo cultured human derived colonic biopsies. In biopsies of UC patients, both during active inflammation and in remission stimulated with LPS+INF-γ, an increased glial cell activation and intestinal damage were evidenced. CBD reduced the expression of S100B and iNOS proteins in the human biopsies confirming its well documented effect in septic mice. The activity of CBD is, at least partly, mediated via the selective PPAR-gamma receptor pathway. CBD targets enteric reactive gliosis, counteracts the inflammatory environment induced by LPS in mice and in human colonic cultures derived from UC patients. These actions lead to a reduction of intestinal damage mediated by PPARgamma receptor pathway. Our results therefore indicate that CBD indeed unravels a new therapeutic strategy to treat inflammatory bowel diseases.

Proinflammatory stimuli activates human-derived enteroglial cells and induces autocrine nitric oxide production.

Background  Enteric glial cells (EGCs) have been recently indicated as key regulators of intestinal inflammation in animals. Whether or not this is true and how these cells participate to inflammatory responses in humans is unknown.

S100B protein in the gut: The evidence for enteroglial- sustained intestinal inflammation

Glial cells in the gut represent the morphological and functional equivalent of astrocytes and microglia in the central nervous system (CNS). In recent years, the role of enteric glial cells (EGCs) has extended from that of simple nutritive support for enteric neurons to that of being pivotal participants in the regulation of inflammatory events in the gut. Similar to the CNS astrocytes, the EGCs physiologically express the S100B protein that exerts either trophic or toxic effects depending on its concentration in the extracellular milieu. In the CNS, S100B overexpression is responsible for the initiation of a gliotic reaction by the release of pro-inflammatory mediators, which may have a deleterious effect on neighboring cells. S100B-mediated pro-inflammatory effects are not limited to the brain: S100B overexpression is associated with the onset and maintenance of inflammation in the human gut too. In this review we describe the major features of EGCs and S100B protein occurring in intestinal inflammation deriving from such.

Imaging neuron-glia interactions in the enteric nervous system

The enteric nervous system (ENS) is a network of neurons and glia within the wall of the gastrointestinal tract that is able to control many aspects of digestive function independently from the central nervous system. Enteric glial cells share several features with astrocytes and are closely associated with enteric neurons and their processes both within enteric ganglia, and along interconnecting fiber bundles. Similar to other parts of the nervous system, there is communication between enteric neurons and glia; enteric glial cells can detect neuronal activity and have the machinery to intermediate neurotransmission. However, due to the close contact between these two cell types and the particular characteristics of the gut wall, the recording of enteric glial cell activity in live imaging experiments, especially in the context of their interaction with neurons, is not straightforward. Most studies have used calcium imaging approaches to examine enteric glial cell activity but in many cases, it is difficult to distinguish whether observed transients arise from glial cells, or neuronal processes or varicosities in their vicinity. In this technical report, we describe a number of approaches to unravel the complex neuron-glia crosstalk in the ENS, focusing on the challenges and possibilities of live microscopic imaging in both animal models and human tissue samples.

Cannabidiol in Inflammatory Bowel Diseases: A Brief Overview

This minireview highlights the importance of cannabidiol (CBD) as a promising drug for the therapy of inflammatory bowel diseases (IBD). Actual pharmacological treatments for IBD should be enlarged toward the search for low‐toxicityand low‐cost drugs that may be given alone or in combination with the conventional anti‐IBD drugs to increase their efficacy in the therapy of relapsing forms of colitis. In the past, Cannabis preparations have been considered new promising pharmacological tools in view of their anti‐inflammatory role in IBD as well as other gut disturbances. However, their use in the clinical therapy has been strongly limited by their psychotropic effects. CBD is a very promising compound since it shares the typical cannabinoid beneficial effects on gut lacking any psychotropic effects. For years, its activity has been enigmatic for gastroenterologists and pharmacologists, but now it is evident that this compound may interact at extra‐cannabinoid system receptor sites, such as peroxisome proliferator‐activated receptor‐gamma. This strategic interaction makes CBD as a potential candidate for the development of a new class of anti‐IBD drugs. Copyright

Evidence for Neuronal and Structural Changes in Submucous Ganglia of Patients With Functional Dyspepsia

OBJECTIVES:An intact and well-functioning enteric nervous system is necessary to efficiently organize gut function. Functional gastrointestinal disorders are pathological entities in which gut function is impaired without a clearly established pathophysiology. On the basis of the relative ease with which intestinal biopsies can be obtained, and taking advantage of a recently developed optical recording technique, we evaluated whether functional neuronal defects exist in enteric nerves of patients with functional dyspepsia (FD).METHODS:The submucous plexus isolated from duodenal biopsies taken from FD patients and control subjects was used to functionally and morphologically examine nerves and ganglionic architecture (neurons and glial cells). In light of previous studies reporting eosinophil and mast cell infiltration in the gut mucosa of FD patients, we also examined whether these cells infiltrated the submucous plexus and whether this correlated with neuronal activity and specific clinical symptoms.RESULTS:We demonstrate that neuronal functioning is impaired in the submucous plexus of FD patients, as shown by decreased calcium responses to depolarization and electrical stimulation. Glial (S100) and neuronal (HuCD) markers show signs of gliosis, altered ganglionic architecture, and neuronal abnormalities in the submucous plexus of FD patients. We found that eosinophils and mast cells infiltrated the submucous layer of FD patients to a much larger extent than in controls. A significant correlation was found between the number of these cells and the calcium transient amplitudes measured in submucous ganglia.CONCLUSIONS:We provide the first direct evidence that FD is characterized by functional and structural abnormalities within the submucous ganglion plexus, which may be of future predictive and diagnostic value in the treatment of FD patients.

Neurotransmitters involved in fast excitatory neurotransmission directly activate enteric glial cells

Background  The intimate association between glial cells and neurons within the enteric nervous system has confounded careful examination of the direct responsiveness of enteric glia to different neuroligands. Therefore, we aimed to investigate whether neurotransmitters known to elicit fast excitatory potentials in enteric nerves also activate enteric glia directly.

Constipation and Botanical Medicines: An Overview

Constipation affects 14% of the adult population globally, mainly women, and significantly impacts on health‐related quality of life. The causes of constipation are mainly three: lifestyle related (functional constipation), disease related, and drug induced. Constipation can generate considerable suffering, including abdominal pain and distension, anorexia, and nausea. The value of some therapeutic measures such as increased fluid intake, physical activity, diet rich in fiber, and nutritional supplements recommended for the relief of constipation is still questionable. The treatment of constipation can be carried out not only with traditional drugs but also with herbal medicines or with nutraceuticals, which are used to prevent or treat the disorder. We have reviewed the most common botanical laxatives such as senna, cascara, frangula, aloe, and rhubarb and their use in the treatment of constipation. Copyright