Substance P mediates pro-inflammatory cytokine release form mesenteric adipocytes in Inflammatory Bowel Disease patients

From gut to brain: understanding the role of microbiota in inflammatory bowel disease

With the proposal of the "biological-psychological-social" model, clinical decision-makers and researchers have paid more attention to the bidirectional interactive effects between psychological factors and diseases. The brain-gut-microbiota axis, as an important pathway for communication between the brain and the gut, plays an important role in the occurrence and development of inflammatory bowel disease. This article reviews the mechanism by which psychological disorders mediate inflammatory bowel disease by affecting the brain-gut-microbiota axis. Research progress on inflammatory bowel disease causing "comorbidities of mind and body" through the microbiota-gut-brain axis is also described. In addition, to meet the needs of individualized treatment, this article describes some nontraditional and easily overlooked treatment strategies that have led to new ideas for "psychosomatic treatment".

Computed tomography-based body composition parameters can predict short-term prognosis in ulcerative colitis patients

OBJECTIVES

Emerging evidence suggests a potential relationship between body composition and short-term prognosis of ulcerative colitis (UC). Early and accurate assessment of rapid remission based on conventional therapy via abdominal computed tomography (CT) images has rarely been investigated. This study aimed to build a prediction model using CT-based body composition parameters for UC risk stratification.

METHODS

In total, 138 patients with abdominal CT images were enrolled. Eleven quantitative parameters related to body composition involving skeletal muscle mass, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) were measured and calculated using a semi-automated segmentation method. A prediction model was established with significant parameters using a multivariable logistic regression. The receiver operating characteristic (ROC) curve was plotted to evaluate prediction performance. Subgroup analyses were implemented to evaluate the diagnostic efficiency of the prediction model between different disease locations, centers, and CT scanners. The Delong test was used for statistical comparison of ROC curves.

RESULTS

VAT density, SAT density, gender, and visceral obesity were significantly statistically different between remission and invalidation groups (all p < 0.05). The accuracy, sensitivity, specificity, and area under the ROC curve (AUC) of the prediction model were 82.61%, 95.45%, 69.89%, and 0.855 (0.792-0.917), respectively. The positive predictive value and negative predictive value were 70.79% and 93.88%, respectively. No significant differences in the AUC of the prediction model were found in different subgroups (all p > 0.05).

CONCLUSIONS

The predicting model constructed with CT-based body composition parameters is a potential non-invasive approach for short-term prognosis identification and risk stratification. Additionally, VAT density was an independent predictor for escalating therapeutic regimens in UC cohorts.

CRITICAL RELEVANCE STATEMENT

The CT images were used for evaluating body composition and risk stratification of ulcerative colitis patients, and a potential non-invasive prediction model was constructed to identify non-responders with conventional therapy for making therapeutic regimens timely and accurately.

KEY POINTS

• CT-based prediction models help divide patients into invalidation and remission groups in UC. • Results of the subgroup analysis confirmed the stability of the prediction model with a high AUC (all > 0.820). • The visceral adipose tissue density was an independent predictor of bad short-term prognosis in UC.

Sensory nerve and neuropeptide diversity in adipose tissues

Both brown and white adipose tissues (BAT/WAT) are innervated by the peripheral nervous system, including efferent sympathetic nerves that communicate from the brain/central nervous system out to the tissue, and afferent sensory nerves that communicate from the tissue back to the brain and locally release neuropeptides to the tissue upon stimulation. This bidirectional neural communication is important for energy balance and metabolic control, as well as maintaining adipose tissue health through processes like browning (development of metabolically healthy brown adipocytes in WAT), thermogenesis, lipolysis, and adipogenesis. Decades of sensory nerve denervation studies have demonstrated the particular importance of adipose sensory nerves for brown adipose tissue and WAT functions, but far less is known about the tissue's sensory innervation compared to the better-studied sympathetic nerves and their neurotransmitter norepinephrine. In this review, we cover what is known and not yet known about sensory nerve activities in adipose, focusing on their effector neuropeptide actions in the tissue.

Visceral Fat Indices: Do They Help Differentiate Crohn's Disease and Intestinal Tuberculosis in Children?

BACKGROUND AND AIMS

Crohn's disease [CD] and intestinal tuberculosis [ITB] are often difficult to differentiate. Mesenteric fat hypertrophy is a feature of CD. We evaluated the utility of fat indices (visceral fat [VF] and subcutaneous fat [SF]) in differentiating CD and ITB in children.

METHODS

Symptomatic children diagnosed to have CD or ITB based on recommended criteria were enrolled. Clinical, anthropometric, and laboratory details were noted. Abdominal fat was measured on computed tomography in supine position at the level of L4 vertebrae. VF and SF area was measured separately by a radiologist, blinded to the diagnosis. The sum of VF and SF was taken as total fat [TF]. VF/SF and VF/TF ratios were calculated.

RESULTS

Thirty-four (age 14 years [10.8-17.0], 14 boys) children were recruited: 12 had CD [seven boys, age 13.0 years] and 22 had ITB [seven boys, age 14.5 years]. VF area was higher in CD compared to ITB (18.34 cm2 [15.62-40.01] vs 6.48 cm2 [2.65-21.96]; p = 0.012). The SF and TF area was similar in ITB and CD. The ratios of VF/SF (0.82 [0.57-1.5] vs 0.33 [0.16-0.48]; p = 0.004) and VF/TF (0.45 [0.36-0.60] vs 0.25 [0.13-0.32]; p = 0.004) were significantly higher in CD. On comparing CD and ITB in boys and girls separately, the difference was significant for boys but not for girls. A VF/SF ratio of 0.609 predicted CD with a good sensitivity [75%] and specificity [86.4%] [area under the curve 0.795, 95% confidence interval 0.636-0.955; p = 0.005].

CONCLUSION

The VF/SF ratio is a simple, non-invasive, objective parameter to differentiate CD and ITB in children, particularly boys. Larger studies are needed to validate this in girls.

Creeping Fat in the Pathogenesis of Crohn's Disease: An Orchestrator or a Silent Bystander?

Although the phenomenon of hypertrophied adipose tissue surrounding inflamed bowel segments in Crohn's disease has been described since 1932, the mechanisms mediating the creeping fat formation and its role in the pathogenesis of the disease have not been fully unraveled. Recent advances demonstrating the multiple actions of adipose tissue beyond energy storage have brought creeping fat to the forefront of scientific research. In Crohn's disease, dysbiosis and transmural injury compromise the integrity of the intestinal barrier, resulting in an excessive influx of intraluminal microbiota and xenobiotics. The gut and peri-intestinal fat are in close anatomic relationship, implying a direct reciprocal immunologic relationship, whereas adipocytes are equipped with an arsenal of innate immunity sensors that respond to invading stimuli. As a result, adipocytes and their progenitor cells undergo profound immunophenotypic changes, leading to adipose tissue remodeling and eventual formation of creeping fat. Indeed, creeping fat is an immunologically active organ that synthesizes various pro- and anti-inflammatory cytokines, profibrotic mediators, and adipokines that serve as paracrine/autocrine signals and regulate immune responses. Therefore, creeping fat appears to be involved in inflammatory signaling, which explains why it has been associated with a higher severity or complicated phenotype of Crohn's disease. Interestingly, there is growing evidence for an alternative immunomodulatory function of creeping fat as a second barrier that prevents an abnormal systemic inflammatory response at the expense of an increasingly proliferating profibrotic environment. Further studies are needed to clarify how this modified adipose tissue exerts its antithetic effect during the course of Crohn's disease.

Role of crustacean female sex hormone in regulating immune response in the mud crab, Scylla paramamosain

Crustacean female sex hormone (CFSH) is responsible for sexual differentiation in crustaceans. The CFSH exhibited an interleukin-17 domain homologous to vertebrate IL-17, a family of inflammatory cytokines that play vital roles in immune defense. However, the immunoregulation of CFSH in crustaceans is a mystery. Therefore, this study aimed to investigate the immune regulatory roles of CFSH and CFSHR in the mud crab Scylla paramamosain. This study's immunofluorescence result revealed that Sp-CFSHR was highly expressed in granulocytes and semi-granulocytes but had moderate expression in hyalinocytes. The expression level of Sp-CFSH transcript in eyestalk ganglia and Sp-CFSHR in hemocytes were significantly up-regulated by the Poly (I:C) stimulation but significantly down-regulated in response to the lipopolysaccharide (LPS) stimulation. In our study, in vitro experiment exhibited that the nuclear transcription factors NF-κB signaling molecules (Sp-Dorsal and Sp-Relish), Sp-STAT, apoptosis-related gene Sp-IAP, and phagocytosis related gene (Sp-Rab5) expressions were significantly increased in hemocytes by recombinant CFSH (rCFSH) in vitro, but the pro-inflammatory cytokine gene (Sp-IL-16) expression was significantly suppressed. Finally, the rCFSH injection significantly up-regulated Sp-Dorsal, Sp-Relish, Sp-IAP, Sp-Caspase, Sp-ALF2, and C-type lectin (Sp-CTL-B) expressions in hemocytes as well as enhanced the bacterial clearance of the mud crab. In conclusion, our results suggested that CFSH may be a counterpart of vertebrate IL-17 in crustaceans that can enhance innate immunity to defense against Vibrionaceae infection via the NF-κB and/or JAK-STAT signaling pathways. This study provides the first evidence that CFSH is involved in the immunoregulation in crustaceans and enriches the insight of neuroendocrine-immune regulatory system, which providing new ideas for disease prevention in the mud crab industry.

Creeping Fat in Crohn's Disease-Surgical, Histological, and Radiological Approaches

During the course of Crohn's disease, the response of mesenteric adipose tissue to the production of inflammatory mediators and bacterial invasion through the intestinal mucosa results in the formation of creeping fat. Creeping fat describes the arresting finger-like projections that surround the inflamed bowel. In this review, the microscopic and macroscopic features of creeping fat and histological evidence for the importance of this tissue are discussed. Moreover, the most recent insights into the radiological assessment of creeping fat in patients with Crohn's disease are reported. Advances in imaging techniques have revolutionized the possibility of visualization and quantification of adipose tissue depots with excellent accuracy. Visceral fat has been significantly correlated with various Crohn's-disease-related outcomes. Despite the difficulties in distinguishing physiologic perienteric fat from creeping fat, the growing interest in fat-wrapping in Crohn's disease has rejuvenated radiologic research. With regard to the noninvasive fat-wrapping assessment, a novel CT enterography-based mesenteric creeping fat index has been developed for the mitigation of the confounding effect of normal retroperitoneal and perienteric adipose tissue. Research on machine learning algorithms and computational radiomics in conjunction with mechanistic studies may be the key for the elucidation of the complex role of creeping fat in Crohn's disease.

Mapping and quantifying neuropeptides in the enteric nervous system

Neuropeptides are a highly diverse group of signaling molecules found in the central nervous system (CNS) and peripheral organs, including the enteric nervous system (ENS). Increasing efforts have been focused on dissecting the role of neuropeptides in both neural- and non-neural-related diseases, as well as their potential therapeutic value. In parallel, accurate knowledge on their source of production and pleiotropic functions is still needed to fully understand their implications in biological processes. This review will focus on the analytical challenges involved in studying neuropeptides, particularly in the ENS, a tissue where their abundance is low, together with opportunities for further technical development.

Systematic Review: The Impact and Importance of Body Composition in Inflammatory Bowel Disease

BACKGROUND AND AIMS

Alterations in body composition are common in inflammatory bowel disease [IBD] and have been associated with differences in patient outcomes. We sought to consolidate knowledge on the impact and importance of body composition in IBD.

METHODS

We performed a systematic search of MEDLINE, EMBASE and conference proceedings by combining two key research themes: inflammatory bowel disease and body composition.

RESULTS

Fifty-five studies were included in this review. Thirty-one focused on the impact of IBD on body composition with a total of 2279 patients with a mean age 38.4 years. Of these, 1071 [47%] were male. In total, 1470 [64.5%] patients had Crohn's disease and 809 [35.5%] had ulcerative colitis. Notably, fat mass and fat-free mass were reduced, and higher rates of sarcopaenia were observed in those with active IBD compared with those in clinical remission and healthy controls. Twenty-four additional studies focused on the impact of derangements in body composition on IBD outcomes. Alterations in body composition in IBD are associated with poorer prognoses including higher rates of surgical intervention, post-operative complications and reduced muscle strength. In addition, higher rates of early treatment failure and primary non-response are seen in patients with myopaenia.

CONCLUSIONS

Patients with IBD have alterations in body composition parameters in active disease and clinical remission. The impacts of body composition on disease outcome and therapy are broad and require further investigation. The augmentation of body composition parameters in the clinical setting has the potential to improve IBD outcomes in the future.

Neuro-immune-metabolism: The tripod system of homeostasis

Homeostatic regulation of cellular and molecular processes is essential for the efficient physiological functioning of body organs. It requires an intricate balance of several networks throughout the body, most notable being the nervous, immune and metabolic systems. Several studies have reported the interactions between neuro-immune, immune-metabolic and neuro-metabolic pathways. Current review aims to integrate the information and show that neuro, immune and metabolic systems form the triumvirate of homeostasis. It focuses on the cellular and molecular interactions occurring in the extremities and intestine, which are innervated by the peripheral nervous system and for the intestine in particular the enteric nervous system. While the interdependence of neuro-immune-metabolic pathways provides a fallback mechanism in case of disruption of homeostasis, in chronic pathologies of continued disequilibrium, the collapse of one system spreads to the other interacting networks as well. Current review illustrates this domino-effect using diabetes as the main example. Together, this review attempts to provide a holistic picture of the integrated network of neuro-immune-metabolism and attempts to broaden the outlook when devising a scientific study or a treatment strategy.

Anatomical Variation in Mesenteric Macrophage Phenotypes in Crohn's Disease

INTRODUCTION:

Clinical trials are currently investigating whether an extended mesenteric resection for ileocecal resections could reduce postoperative recurrence in Crohn's disease. Resection of the mesorectum, which contains proinflammatory macrophages, during proct(ocol)ectomy, is associated with reduced recurrent inflammation and improved wound healing. We aimed to characterize the macrophages in the ileocecal mesentery, which were compared with those in the mesorectum, to provide a biological rationale for the ongoing trials.

METHODS:

In 13 patients with Crohn's disease and 4 control patients undergoing a proctectomy, tissue specimens were sampled at 3 locations from the mesorectum: distal (rectum), middle, and proximal (sigmoid). In 38 patients with Crohn's disease and 7 control patients undergoing ileocecal resections, tissue specimens also obtained from 3 locations: adjacent to the inflamed terminal ileum, adjacent to the noninflamed ileal resection margin, and centrally along the ileocolic artery. Immune cells from these tissue specimens were analyzed by flow cytometry for expression of CD206 to determine their inflammatory status.

RESULTS:

In the mesorectum, a gradient from proinflammatory to regulatory macrophages from distal to proximal was observed, corresponding to the adjacent inflammation of the intestine. By contrast, the ileocecal mesentery did not contain high amounts of proinflammatory macrophages adjacent to the inflamed tissue, and a gradient toward a more proinflammatory phenotype was seen in the central mesenteric area.

DISCUSSION:

Although the mesentery is a continuous structure, the mesorectum and the ileocecal mesentery show different immunological characteristics. Therefore, currently, there is no basis to perform an extended ileocecal resection in patients with Crohn's disease.

Crosstalk Between Epithelial Cells, Neurons and Immune Mediators in HSV-1 Skin Infection

Herpes simplex virus type 1 (HSV-1) infection is highly prevalent in humans, with approximately two-thirds of the world population living with this virus. However, only a fraction of those carrying HSV-1, which elicits lifelong infections, are symptomatic. HSV-1 mainly causes lesions in the skin and mucosae but reaches the termini of sensory neurons innervating these tissues and travels in a retrograde manner to the neuron cell body where it establishes persistent infection and remains in a latent state until reactivated by different stimuli. When productive reactivations occur, the virus travels back along axons to the primary infection site, where new rounds of replication are initiated in the skin, in recurrent or secondary infections. During this process, new neuron infections occur. Noteworthy, the mechanisms underlying viral reactivations and the exit of latency are somewhat poorly understood and may be regulated by a crosstalk between the infected neurons and components of the immune system. Here, we review and discuss the immune responses that occur at the skin during primary and recurrent infections by HSV-1, as well as at the interphase of latently-infected neurons. Moreover, we discuss the implications of neuronal signals over the priming and migration of immune cells in the context of HSV-1 infection.

Activated intestinal muscle cells promote preadipocyte migration: a novel mechanism for creeping fat formation in Crohn's disease

OBJECTIVE

Creeping fat, the wrapping of mesenteric fat around the bowel wall, is a typical feature of Crohn's disease, and is associated with stricture formation and bowel obstruction. How creeping fat forms is unknown, and we interrogated potential mechanisms using novel intestinal tissue and cell interaction systems.

DESIGN

Tissues from normal, UC, non-strictured and strictured Crohn's disease intestinal specimens were obtained. The muscularis propria matrisome was determined via proteomics. Mesenteric fat explants, primary human preadipocytes and adipocytes were used in multiple ex vivo and in vitro cell migration systems on muscularis propria muscle cell derived or native extracellular matrix. Functional experiments included integrin characterisation via flow cytometry and their inhibition with specific blocking antibodies and chemicals.

RESULTS

Crohn's disease muscularis propria cells produced an extracellular matrix scaffold which is in direct spatial and functional contact with the immediately overlaid creeping fat. The scaffold contained multiple proteins, but only fibronectin production was singularly upregulated by transforming growth factor-β1. The muscle cell-derived matrix triggered migration of preadipocytes out of mesenteric fat, fibronectin being the dominant factor responsible for their migration. Blockade of α5β1 on the preadipocyte surface inhibited their migration out of mesenteric fat and on 3D decellularised intestinal tissue extracellular matrix.

CONCLUSION

Crohn's disease creeping fat appears to result from the migration of preadipocytes out of mesenteric fat and differentiation into adipocytes in response to an increased production of fibronectin by activated muscularis propria cells. These new mechanistic insights may lead to novel approaches for prevention of creeping fat-associated stricture formation.

Changes in the expression of substance P in nerve fibres of the colonic mucosa in dogs suffering from inflammatory bowel disease

Due to its difficult diagnosis and complicated treatment, inflammatory bowel disease (IBD) in dogs is a challenge for the veterinarian. Several aspects connected with pathological changes during IBD still remain unknown. Since one of these aspects is the participation of intestinal innervation in the evolution of the disease, the aim of this study was to demonstrate changes in the number and distribution of intramucosal colonic nerve fibres immunoreactive to substance P (SP) arising as the disease progresses. SP is one of the most important neuronal factors in intestinal innervation which, among other tasks, takes part in the conduction of pain stimuli. Using routine immunofluorescence technique, the density of nerve fibres containing SP was evaluated within mucosal biopsy specimens collected from the descending colon of healthy dogs and animals suffering from IBD of varying severity. The results of the study indicate that during severe IBD the number of nerve fibres containing SP located in the colonic mucosal layer increases in comparison to control animals. The number of SP-positive intramucosal nerves amounted to 10.99 ± 2.11 nerves per observation field in healthy dogs, 14.62 ± 2.86 in dogs with mild IBD, 14.80 ± 0.91 in dogs with moderate IBD and 19.03 ± 6.11 in animals with severe IBD. The observed changes were directly proportional to the intensity of the disease process. These observations may suggest a role of this neuronal substance in pathological processes occurring during IBD. Although the exact mechanism of the observed changes has not been completely explained, the results obtained in this investigation may contribute to improving the diagnosis and treatment of this disease, as well as the staging of canine IBD in veterinary practice.

Elafin inhibits obesity, hyperglycemia, and liver steatosis in high-fat diet-treated male mice

Elafin is an antimicrobial and anti-inflammatory protein. We hypothesize that elafin expression correlates with diabetes. Among non-diabetic and prediabetic groups, men have significantly higher serum elafin levels than women. Men with type 2 diabetes mellitus (T2DM) have significantly lower serum elafin levels than men without T2DM. Serum elafin levels are inversely correlated with fasting blood glucose and hemoglobin A1c levels in men with T2DM, but not women with T2DM. Lentiviral elafin overexpression inhibited obesity, hyperglycemia, and liver steatosis in high-fat diet (HFD)-treated male mice. Elafin-overexpressing HFD-treated male mice had increased serum leptin levels, and serum exosomal miR181b-5p and miR219-5p expression. Transplantation of splenocytes and serum exosomes from elafin-overexpressing HFD-treated donor mice reduced food consumption and fat mass, and increased adipose tissue leptin mRNA expression in HFD-treated recipient mice. Elafin improved leptin sensitivity via reduced interferon-gamma expression and induced adipose leptin expression via increased miR181b-5p and miR219-5p expression. Subcutaneous and oral administration of modified elafin inhibited obesity, hyperglycemia, and liver steatosis in the HFD-treated mice. Circulating elafin levels are associated with hyperglycemia in men with T2DM. Elafin, via immune-derived miRNAs and cytokine, activates leptin sensitivity and expression that subsequently inhibit food consumption, obesity, hyperglycemia, and liver steatosis in HFD-treated male mice.

The Neuropeptide System and Colorectal Cancer Liver Metastases: Mechanisms and Management

Colorectal cancer (CRC), classified as the third most prevalent cancer worldwide, remains to be a clinical and research challenge. It is estimated that ~50% of CRC patients die from distant metastases, with treatment of this complication still posing significant difficulties. While liver metastasis (LM) cascade is known in the literature, its mechanisms are still unclear and remain studied in different research models. A connection is suggested between nervous system dysfunctions and a range of Neurotransmitters (Nts) (including Neuropeptides, NPs), Neurotrophins (Ntt) and their receptors (Rs) in CRC liver metastasis development. Studies on the role of NP/NP-Rs in the progression and metastasis of CRC, show the complexity of brain–tumor interactions, caused by their different forms of release to the extracellular environment (endocrine, autocrine, paracrine and neurocrine). Many stages of LM are connected to the activity of pro-inflammatory, e.g., Corticotropin-releasing Hormone Receptor 1 (CRHR1), Neuropeptide Y (NPY) and Neurotensin (NT), anti-inflammatory, e.g., Calcitonin Gene-related Peptide (CGRP), CRHR2 and Vasoactive Intestinal Polypeptide (VIP) or dual role neuropeptides, e.g., Substance P (SP). The regulation of the local immunological profile (e.g., CRH/CRHRs), dysfunctions of enteroprotective role of NPs on epithelial cells (e.g., NT/NT-R), as well as structural-functional changes in enteric nervous system innervation of the tumor are also important. More research is needed to understand the exact mechanisms of communication between the neurons and tumor cells. The knowledge on the mechanisms regulating tumor growth and different stages of metastasis, as well as effects of the action of a numerous group of Nts/NPs/Ntt as growth factors, have implications for future therapeutic strategies. To obtain the best treatment outcomes, it is important to use signaling pathways common for many NPs, as well to develop a range of broad-spectrum antagonists. This review aims to summarize the current knowledge on the importance of neuroactive molecules in the promotion of the invasion-metastasis cascade in CRC, as well as the improvements of clinical management of CRC liver metastasis.

The Neuropeptide System and Colorectal Cancer Liver Metastases: Mechanisms and Management

Colorectal cancer (CRC), classified as the third most prevalent cancer worldwide, remains to be a clinical and research challenge. It is estimated that ~50% of CRC patients die from distant metastases, with treatment of this complication still posing significant difficulties. While liver metastasis (LM) cascade is known in the literature, its mechanisms are still unclear and remain studied in different research models. A connection is suggested between nervous system dysfunctions and a range of Neurotransmitters (Nts) (including Neuropeptides, NPs), Neurotrophins (Ntt) and their receptors (Rs) in CRC liver metastasis development. Studies on the role of NP/NP-Rs in the progression and metastasis of CRC, show the complexity of brain–tumor interactions, caused by their different forms of release to the extracellular environment (endocrine, autocrine, paracrine and neurocrine). Many stages of LM are connected to the activity of pro-inflammatory, e.g., Corticotropin-releasing Hormone Receptor 1 (CRHR1), Neuropeptide Y (NPY) and Neurotensin (NT), anti-inflammatory, e.g., Calcitonin Gene-related Peptide (CGRP), CRHR2 and Vasoactive Intestinal Polypeptide (VIP) or dual role neuropeptides, e.g., Substance P (SP). The regulation of the local immunological profile (e.g., CRH/CRHRs), dysfunctions of enteroprotective role of NPs on epithelial cells (e.g., NT/NT-R), as well as structural-functional changes in enteric nervous system innervation of the tumor are also important. More research is needed to understand the exact mechanisms of communication between the neurons and tumor cells. The knowledge on the mechanisms regulating tumor growth and different stages of metastasis, as well as effects of the action of a numerous group of Nts/NPs/Ntt as growth factors, have implications for future therapeutic strategies. To obtain the best treatment outcomes, it is important to use signaling pathways common for many NPs, as well to develop a range of broad-spectrum antagonists. This review aims to summarize the current knowledge on the importance of neuroactive molecules in the promotion of the invasion-metastasis cascade in CRC, as well as the improvements of clinical management of CRC liver metastasis.

High circulating elafin levels are associated with Crohn's disease-associated intestinal strictures

Background

Antimicrobial peptide expression is associated with disease activity in inflammatory bowel disease (IBD) patients. IBD patients have abnormal expression of elafin, a human elastase-specific protease inhibitor and antimicrobial peptide. We determined elafin expression in blood, intestine, and mesenteric fat of IBD and non-IBD patients.

Methods

Serum samples from normal and IBD patients were collected from two UCLA cohorts. Surgical resection samples of human colonic and mesenteric fat tissues from IBD and non-IBD (colon cancer) patients were collected from Cedars-Sinai Medical Center.

Results

High serum elafin levels were associated with a significantly elevated risk of intestinal stricture in Crohn’s disease (CD) patients. Microsoft Azure Machine learning algorithm using serum elafin levels and clinical data identified stricturing CD patients with high accuracy. Serum elafin levels had weak positive correlations with clinical disease activity (Partial Mayo Score and Harvey Bradshaw Index), but not endoscopic disease activity (Mayo Endoscopic Subscore and Simple Endoscopic Index for CD) in IBD patients. Ulcerative colitis (UC) patients had high serum elafin levels. Colonic elafin mRNA and protein expression were not associated with clinical disease activity and histological injury in IBD patients, but stricturing CD patients had lower colonic elafin expression than non-stricturing CD patients. Mesenteric fat in stricturing CD patients had significantly increased elafin mRNA and protein expression, which may contribute to high circulating elafin levels. Human mesenteric fat adipocytes secrete elafin protein.

Conclusions

High circulating elafin levels are associated with the presence of stricture in CD patients. Serum elafin levels may help identify intestinal strictures in CD patients.

miR-206 Promotes Cancer Progression by Targeting Full-Length Neurokinin-1 Receptor in Breast Cancer

Substance P plays a pivotal role in human cancer development and progression by binding to its receptor, neurokinin-1. Neurokinin-1 has 2 isoforms: full-length neurokinin-1 and truncated neurokinin-1, the latter lacking the cytoplasmic terminal 96-amino acid residues of the full-length protein. We have identified 3 candidate miR-206 target sites within the 3′-untranslated region of the full-length neurokinin-1 gene from bioinformatics database searches. In the present study, real-time quantitative polymerase chain reaction was performed to quantify the expression of miR-206, and the expression of neurokinin-1 and full-length neurokinin-1 was detected by immunohistochemistry in 82 clinical cases of breast cancer and paired adjacent normal tissues. The miR-206 target gene was demonstrated by using a dual-luciferase reporter assay, quantitative real-time polymerase chain reaction, and Western blotting. Transwell migration and invasion, colony formation, and proliferation assays were performed to evaluate the effects of miR-206 expression on various aspects of breast cancer cell behavior in vitro. We showed that miR-206 expression is upregulated in breast cancer cell lines and breast cancer tissues when compared to that in adjacent normal tissues, and full-length neurokinin-1 expression inversely correlates with Tumor Lymph Node Metastasis (TNM) stage and lymph node metastasis. Western blotting, quantitative real-time polymerase chain reaction, and dual-luciferase reporter assays demonstrated that miR-206 binds the 3′-untranslated region of full-length neurokinin-1 messenger RNA, regulating protein expression. We showed that the overexpression of miR-206 promotes breast cancer cell invasion, migration, proliferation, and colony formation in vitro. The present study furthers the current understanding of the mechanisms underlying breast cancer pathogenesis and may be useful for the development of novel targeted therapies.

Role of Obesity, Mesenteric Adipose Tissue, and Adipokines in Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBDs) are a group of disorders which include ulcerative colitis and Crohn's disease. Obesity is becoming increasingly more common among patients with inflammatory bowel disease and plays a role in the development and course of the disease. This is especially true in the case of Crohn's disease. The recent results indicate a special role of visceral adipose tissue and particularly mesenteric adipose tissue, also known as "creeping fat", in pathomechanism, leading to intestinal inflammation. The involvement of altered adipocyte function and the deregulated production of adipokines, such as leptin and adiponectin, has been suggested in pathogenesis of IBD. In this review, we discuss the epidemiology and pathophysiology of obesity in IBD, the influence of a Western diet on the course of Crohn's disease and colitis in IBD patients and animal's models, and the potential role of adipokines in these disorders. Since altered body composition, decrease of skeletal muscle mass, and development of pathologically changed mesenteric white adipose tissue are well-known features of IBD and especially of Crohn's disease, we discuss the possible crosstalk between adipokines and myokines released from skeletal muscle during exercise with moderate or forced intensity. The emerging role of microbiota and the antioxidative and anti-inflammatory enzymes such as intestinal alkaline phosphatase is also discussed, in order to open new avenues for the therapy against intestinal perturbations associated with IBD.

Possible Molecular Mediators Involved and Mechanistic Insight into Fibromyalgia and Associated Co-morbidities

Fibromyalgia is a chronic complex syndrome of non-articulate origin characterized by musculoskeletal pain, painful tender points, sleep problems and co-morbidities including depression, migraine. The etiopathogenesis of fibromyalgia is complex, variable and remains inconclusive. The etiological factors that have been defined include stress, genetic predisposition and environmental components. As per the reports of the American College of Rheumatology (ACR) the prevalence of fibromyalgia varies from 2 to 22% among the general population with poor diagnostic features primarily pain. Fibromyalgia encompasses a spectrum of co-morbid conditions with multifarious pathogenesis. The highly prevalent manifestations of fibromyalgia include heterogeneous pain and aches. Biochemical and neurobiological elements of fibromyalgia include neurotransmitters, hypothalamic pituitary adrenal axis (HPA axis), inflammatory cytokines, monoaminergic pathway, opioid peptides, sex hormones, nerve growth factor (NGF) and local free radical insult. An imbalance in the serotonergic system is the major underlying etiological factor that has been explored most widely. Owing to complex interplay of diverse pathophysiological pathways, overlapping co-morbidities such as depression have been clinically observed. Therapeutic management of fibromyalgia involves both non pharmacological and pharmacological measures. The current review presents various dysregulations and their association with symptoms of fibromyalgia along with their underlying neurobiological aspects.

Neuro-Immune Networks in Gastrointestinal Disorders

Tissue homeostasis is controlled by multilateral cell interactions. Established in autoimmune diseases of the central nervous system, growing evidence shows a fundamental role of bidirectional communication between the nervous and immune systems in various gastrointestinal disorders. Primarily the primary sensory nervous system seems to play an important role in this cross talk because of its ability for transducing inflammatory signals and to convey them to the central nervous system, which in turn responds in an efferent manner (gut-brain axis vs. brain-gut axis). Moreover, sensory neurons that play a central role in pain processing immediately respond to inflammatory stimuli through releasing a myriad of immunomodulatory neuropeptides and neurotransmitters whose receptors are expressed in different immune cell populations. Thus, a better understanding of neuro-immune networks will pave the way to novel therapeutic strategies in inflammatory as well as functional gastrointestinal disorders.

Novel Imaging Approaches in Inflammatory Bowel Diseases

Inflammatory bowel diseases are chronic autoimmune conditions of the gastrointestinal tract, mainly grouped into ulcerative colitis or Crohn's disease. Traditionally, symptoms have been used to guide IBD management, but this approach is fatally flawed, as symptoms don't correlate with disease activity and often fail to predict disease complications, especially with Crohn's disease. Hence, there is increasing recognition of the need for treatment algorithms based on objective measures of bowel inflammation. In this review, we will focus on advancements in the endoscopic and radiological imaging armamentarium that allow detailed assessments from intestinal mucosa to mesentery.

Adult Inflammatory Bowel Disease, Physical Rehabilitation, and Structured Exercise

10.1093/ibd/izy199_video1Video 1.Video 1. Watch now at https://academic.oup.com/asj/article-lookup/doi/10.1093/ibd/izy199izy199.video15790841578001.

Mesenteric Adipose-derived Stromal Cells From Crohn's Disease Patients Induce Protective Effects in Colonic Epithelial Cells and Mice With Colitis

Mesenteric adipose tissue hyperplasia is a hallmark of Crohn's disease (CD). Recently, we showed that mesenteric adipose-derived stromal cells (ADSCs) from CD, ulcerative colitis, and control patients synthesize and release adipokines in a disease-dependent manner. Here we examined the expression profiles of CD and control patient-derived mesenteric ADSCs and studied the effects of their extracellular mediators on colonocyte signaling in vitro and experimental colitis in vivo. ADSCs were isolated from mesenteric fat of control and CD patients. Microarray profiling and network analysis were performed in ADSCs and human colonocytes treated with conditioned media from cultured ADSCs. Mice with acute colitis received daily injections of conditioned media from patient-derived ADSCs, vehicle, or apolactoferrin. Proliferative responses were evaluated in conditioned media-treated colonocytes and mouse colonic epithelium. Total protein was isolated from cultured colonocytes after treatment with apolactoferrin for Western blot analysis of phosphorylated intracellular signaling kinases. Microarray profiling revealed differential mRNA expression in CD patient-derived ADSCs compared with controls, including lactoferrin. Administration of CD patient-derived medium or apolactoferrin increased colonocyte proliferation compared with controls. Conditioned media from CD patient-derived ADSCs or apolactoferrin attenuated colitis severity in mice and enhanced colonocyte proliferation in vivo. ADSCs from control and CD patients show disease-dependent inflammatory responses and alter colonic epithelial cell signaling in vitro and in vivo. Furthermore, we demonstrate lactoferrin production by adipose tissue, specifically mesenteric ADSCs. We suggest that mesenteric ADSC-derived lactoferrin may mediate protective effects and participate in the pathophysiology of CD by promoting colonocyte proliferation and the resolution of inflammation.

Anatomical, Physiological, and Functional Diversity of Adipose Tissue

Adipose tissue depots can exist in close association with other organs, where they assume diverse, often non-traditional functions. In stem cell-rich skin, bone marrow, and mammary glands, adipocytes signal to and modulate organ regeneration and remodeling. Skin adipocytes and their progenitors signal to hair follicles, promoting epithelial stem cell quiescence and activation, respectively. Hair follicles signal back to adipocyte progenitors, inducing their expansion and regeneration, as in skin scars. In mammary glands and heart, adipocytes supply lipids to neighboring cells for nutritional and metabolic functions, respectively. Adipose depots adjacent to skeletal structures function to absorb mechanical shock. Adipose tissue near the surface of skin and intestine senses and responds to bacterial invasion, contributing to the body's innate immune barrier. As the recognition of diverse adipose depot functions increases, novel therapeutic approaches centered on tissue-specific adipocytes are likely to emerge for a range of cancers and regenerative, infectious, and autoimmune disorders.

Obesity/Bariatric Surgery and Crohn's Disease

BACKGROUND

Crohn's disease (CD) following bariatric surgery has been previously described. It is not clear whether the clinical entity is due to rapid metabolism of fat, change in the bacterial milieu of the bowel, the loss of defense mechanisms of the stomach, or even a coincidence.

OBJECTIVES

To present observations which might serve to sort out these various etiologies.

DESIGN

We present 5 cases of colitis, ileocolitis or enteritis, some with fistula formation, with clinical onset following bariatric surgery and add these to the 7 cases previously identified as CD reported elsewhere. We provide the clinical features of these 12 cases to reconcile with causative mechanisms.

LIMITATIONS

It remains possible that the onset of CD (or other inflammatory bowel disease) precedes the bariatric surgery which then accelerates the clinical manifestations described. Furthermore, without controls the association could remain a coincidence.

CONCLUSIONS

We review the evidence for release of proinflammatory cells and cytokines contained in fat following the bariatric surgery, and also consider the roles that the surgical resection of stomach and shortening of the bowel may also bring about this syndrome. The earlier onset is more likely due to surgical loss of defenses of the stomach and the later onset to a metabolic alteration of the presurgical obesity, involving fat metabolism, and/or the microbiome. The role of characteristic creeping fat of CD is also addressed.

In vitro enteroid-derived three-dimensional tissue model of human small intestinal epithelium with innate immune responses

There is a need for functional in vitro 3D human intestine systems that can bridge the gap between conventional cell culture studies and human trials. The successful engineering in vitro of human intestinal tissues relies on the use of the appropriate cell sources, biomimetic scaffolds, and 3D culture conditions to support vital organ functions. We previously established a compartmentalized scaffold consisting of a hollow space within a porous bulk matrix, in which a functional and physiologically relevant intestinal epithelium system was generated using intestinal cell lines. In this study, we adopt the 3D scaffold system for the cultivation of stem cell-derived human small intestinal enteriods (HIEs) to engineer an in vitro 3D model of a nonstransformed human small intestinal epithelium. Characterization of tissue properties revealed a mature HIE-derived epithelium displaying four major terminally differentiated epithelial cell types (enterocytes, Goblet cells, Paneth cells, enteroendocrine cells), with tight junction formation, microvilli polarization, digestive enzyme secretion, and low oxygen tension in the lumen. Moreover, the tissue model demonstrates significant antibacterial responses to E. coli infection, as evidenced by the significant upregulation of genes involved in the innate immune response. Importantly, many of these genes are activated in human patients with inflammatory bowel disease (IBD), implicating the potential application of the 3D stem-cell derived epithelium for the in vitro study of host-microbe-pathogen interplay and IBD pathogenesis.

Role of G protein-coupled receptors-microRNA interactions in gastrointestinal pathophysiology

G protein-coupled receptors (GPCRs) make up the largest transmembrane receptor superfamily in the human genome and are expressed in nearly all gastrointestinal cell types. Coupling of GPCRs and their respective ligands activates various phosphotransferases in the cytoplasm, and, thus, activation of GPCR signaling in intestine regulates many cellular and physiological processes. Studies in microRNAs (miRNAs) demonstrate that they represent critical epigenetic regulators of different pathophysiological responses in different organs and cell types in humans and animals. Here, we reviewed recent research on GPCR-miRNA interactions related to gastrointestinal pathophysiology, such as inflammatory bowel diseases, irritable bowel syndrome, and gastrointestinal cancers. Given that the presence of different types of cells in the gastrointestinal tract suggests the importance of cell-cell interactions in maintaining gastrointestinal homeostasis, we also discuss how GPCR-miRNA interactions regulate gene expression at the cellular level and subsequently modulate gastrointestinal pathophysiology through molecular regulatory circuits and cell-cell interactions. These studies helped identify novel molecular pathways leading to the discovery of potential biomarkers for gastrointestinal diseases.

The body composition profile is associated with response to anti-TNF therapy in Crohn's disease and may offer an alternative dosing paradigm

BACKGROUND

Anti-tumour necrosis factor (TNF)s form a major part of therapy in Crohn's disease and have a primary nonresponse rate of 10%-30% and a secondary loss of response rate of 5% per year. Myopenia is prevalent in Crohn's disease and is measured using body composition analysis tools.

AIM

To test the hypothesis that body composition can predict outcomes of anti-TNF primary nonresponse and secondary loss of response.

METHODS

Between January 2007 and June 2012, 106 anti-TNF naïve patients underwent anti-TNF therapy for Crohn's disease with body composition parameters analysed using CT scans to estimate body fat-free mass. The outcome measures were primary nonresponse and secondary loss of response. COX-regression analysis was used with 3 year follow-up data.

RESULTS

A total of 106 patients were included for analysis with 26 (24.5%) primary nonresponders and 29 (27.4%) with secondary loss of response to anti-TNF therapy. Sex-specific cut-offs for muscle and fat were ascertained by stratification analysis. On univariate analysis, primary nonresponse was associated with low albumin (OR 0.94; 0.88-0.99, P = .04) and presence of myopenia (OR 4.69; 1.83-12.01, P = .001) when taking into account patient's medical therapy, severity of disease and body composition. On multivariate analysis, presence of myopenia was associated with primary nonresponse (OR 2.93; 1.28-6.71, P = .01). Immunomodulator therapy was associated with decreased secondary loss of response (OR 0.48; 0.23-0.98, P = .04). BMI was poorly correlated with lean body mass (r² = 0.15, P = .54).

CONCLUSIONS

In this cohort study, body composition profiles did not correlate well with BMI. Myopenia was associated with primary nonresponse with potential implications for dosing and serves as an explanation for pharmacokinetic failure.

Beneficial Effect of Voluntary Exercise on Experimental Colitis in Mice Fed a High-Fat Diet: The Role of Irisin, Adiponectin and Proinflammatory Biomarkers

Inflammatory bowel diseases (IBDs) are a heterogeneous group of disorders exhibited by two major phenotypic forms: Crohn‘s disease and ulcerative colitis. Although the aetiology of IBD is unknown, several factors coming from the adipose tissue and skeletal muscles, such as cytokines, adipokines and myokines, were suggested in the pathogenesis of ulcerative colitis; however, it has not been extensively studied whether voluntary exercise can ameliorate that disorder. We explored the effect of moderate exercise (i.e., voluntary wheel running) on the disease activity index (DAI), colonic blood flow (CBF), plasma irisin and adiponectin levels and real-time PCR expression of proinflammatory markers in mesenteric fat in mice with 2,4,6-trinitrobenzenesulfonic acid (TNBS) colitis fed a high-fat diet (HFD) compared to those on a standard chow diet (SD). Macroscopic and microscopic colitis in sedentary SD mice was accompanied by a significant fall in CBF, some increase in colonic tissue weight and a significant increase in the plasma levels of tumour necrosis factor-alpha (TNF-α), IL-6, monocyte chemotactic protein 1 (MCP-1) and IL-13 (p < 0.05). In sedentary HFD mice, colonic lesions were aggravated, colonic tissue weight increased and the plasma TNF-α, IL-6, MCP-1, IL-1β and leptin levels significantly increased. Simultaneously, a significant decrease in the plasma irisin and adiponectin levels was observed in comparison with SD mice (p < 0.05). Exercise significantly decreased macroscopic and microscopic colitis, substantially increased CBF and attenuated the plasma TNF-α, IL-6, MCP-1, IL-1β and leptin levels while raising the plasma irisin and the plasma and WAT concentrations of adiponectin in HFD mice (p < 0.05). We conclude that: (1) experimental colitis is exacerbated in HFD mice, possibly due to a fall in colonic microcirculation and an increase in the plasma and mesenteric fat content of proinflammatory biomarkers; and (2) voluntary physical activity can attenuate the severity of colonic damage in mice fed a HFD through the release of protective irisin and restoration of plasma adiponectin.

The mesentery in Crohn's disease: friend or foe?

PURPOSE OF REVIEW

This article assesses the role of the mesentery in Crohn's disease.

RECENT FINDINGS

The mesentery is centrally positioned both anatomically and physiologically. Overlapping mesenteric and submucosal mesenchymal contributions are important in the pathobiology of Crohn's disease. Mesenteric contributions explain the topographic distribution of Crohn's disease in general and mucosal disease in particular. Operative strategies that are mesenteric based (i.e. mesocolic excision) may reduce rates of postoperative recurrence.

SUMMARY

The net effect of mesenteric events in Crohn's disease is pathologic. This can be targeted by operative means.

VIDEO ABSTRACT

http://links.lww.com/COG/A18.

Can exercise affect the course of inflammatory bowel disease? Experimental and clinical evidence

The inflammatory bowel disease (IBD) consisting of Crohn's disease (CD) and ulcerative colitis (UC) are defined as idiopathic, chronic and relapsing intestinal disorders occurring in genetically predisposed individuals exposed to environmental risk factors such as diet and microbiome changes. Since conventional drug therapy is expensive and not fully efficient, there is a need for alternative remedies that can improve the outcome in patients suffering from IBD. Whether exercise, which has been proposed as adjunct therapy in IBD, can be beneficial in patients with IBD remains an intriguing question. In this review, we provide an overview of the effects of exercise on human IBD and experimental colitis in animal models that mimic human disease, although the information on exercise in human IBD are sparse and poorly understood. Moderate exercise can exert a beneficial ameliorating effect on IBD and improve the healing of experimental animal colitis due to the activity of protective myokines such as irisin released from working skeletal muscles. CD patients with higher levels of exercise were significantly less likely to develop active disease at six months. Moreover, voluntary exercise has been shown to exert a positive effect on IBD patients' mood, weight maintenance and osteoporosis. On the other hand, depending on its intensity and duration, exercise can evoke transient mild systemic inflammation and enhances pro-inflammatory cytokine release, thereby exacerbating the gastrointestinal symptoms. We discuss recent advances in the mechanism of voluntary and strenuous exercise affecting the outcome of IBD in patients and experimental animal models.