VEGF, basic-FGF, and TGF-beta in Crohn's disease and ulcerative colitis: a novel mechanism of chronic intestinal inflammation

Circulating VEGF and inflammatory bowel disease: a bidirectional mendelian randomization

Introduction: Prior observational studies have suggested an association between circulating vascular endothelial growth factor (VEGF) levels and inflammatory bowel disease (IBD). This study sought to demonstrate the directionality of the association between circulating VEGF and particular forms of IBD as well as if there is a causal relationship between them. Methods: We collected summary data from relevant genome-wide association studies (GWASs) to assess the validity of causality, and a two-sample bidirectional Mendelian randomization (MR) study and sensitivity testing were performed to assess the causal relationship between circulating VEGF and IBD risk, including Crohn's disease and ulcerative colitis. Results: Our findings revealed a direct causal link between circulating VEGF and Crohn's disease (b 0.195, se 0.078, p < 0.013). However, neither circulating VEGF nor ulcerative colitis were shown to be causally linked (p > 0.025), nor was there proof of a reverse causal relationship from IBD to VEGF. Discussion: In conclusion, circulating VEGF shows a cause-and-effect relationship with Crohn's disease.

Fundamentals and developments in fluorescence-guided cancer surgery

Fluorescence-guided surgery using tumour-targeted imaging agents has emerged over the past decade as a promising and effective method of intraoperative cancer detection. An impressive number of fluorescently labelled antibodies, peptides, particles and other molecules related to cancer hallmarks have been developed for the illumination of target lesions. New approaches are being implemented to translate these imaging agents into the clinic, although only a few have made it past early-phase clinical trials. For this translational process to succeed, target selection, imaging agents and their related detection systems and clinical implementation have to operate in perfect harmony to enable real-time intraoperative visualization that can benefit patients. Herein, we review key aspects of this imaging cascade and focus on imaging approaches and methods that have helped to shed new light onto the field of intraoperative fluorescence-guided cancer surgery with the singular goal of improving patient outcomes.

Role of mesenteric component in Crohn’s disease: A friend or foe?

Crohn’s disease (CD) is a complex and relapsing gastrointestinal disease with mesenteric alterations. The mesenteric neural, vascular, and endocrine systems actively take part in the gut dysbiosis-adaptive immunity-mesentery-body axis, and this axis has been proven to be bidirectional. The abnormalities of morphology and function of the mesenteric component are associated with intestinal inflammation and disease progress of CD via responses to afferent signals, neuropeptides, lymphatic drainage, adipokines, and functional cytokines. The hypertrophy of mesenteric adipose tissue plays important roles in the pathogenesis of CD by secreting large amounts of adipokines and representing a rich source of proinflammatory or profibrotic cytokines. The vascular alteration, including angiogenesis and lymphangiogenesis, is concomitant in the disease course of CD. Of note, the enlarged and obstructed lymphatic vessels, which have been described in CD patients, are likely related to the early onset submucosa edema and being a cause of CD. The function of mesenteric lymphatics is influenced by endocrine of mesenteric nerves and adipocytes. Meanwhile, the structure of the mesenteric lymphatic vessels in hypertrophic mesenteric adipose tissue is mispatterned and ruptured, which can lead to lymph leakage. Leaky lymph factors can in turn stimulate adipose tissue to proliferate and effectively elicit an immune response. The identification of the role of mesentery and the crosstalk between mesenteric tissues in intestinal inflammation may shed light on understanding the underlying mechanism of CD and help explore new therapeutic targets.

Deubiquitylating enzymes: potential target in autoimmune diseases

The ubiquitin-proteasome pathway is responsible for the turnover of different cellular proteins, such as transport proteins, presentation of antigens to the immune system, control of the cell cycle, and activities that promote cancer. The enzymes which remove ubiquitin, deubiquitylating enzymes (DUBs), play a critical role in central and peripheral immune tolerance to prevent the development of autoimmune diseases and thus present a potential therapeutic target for the treatment of autoimmune diseases. DUBs function by removing ubiquitin(s) from target protein and block ubiquitin chain elongation. The addition and removal of ubiquitin molecules have a significant impact on immune responses. DUBs and E3 ligases both specifically cleave target protein and modulate protein activity and expression. The balance between ubiquitylation and deubiquitylation modulates protein levels and also protein interactions. Dysregulation of the ubiquitin-proteasome pathway results in the development of various autoimmune diseases such as inflammatory bowel diseases (IBD), psoriasis, multiple sclerosis (MS), systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). This review summarizes the current understanding of ubiquitination in autoimmune diseases and focuses on various DUBs responsible for the progression of autoimmune diseases.

Cross-Talk Between Inflammation and Fibroblast Growth Factor 10 During Organogenesis and Pathogenesis: Lessons Learnt From the Lung and Other Organs

The adult human lung is constantly exposed to irritants like particulate matter, toxic chemical compounds, and biological agents (bacteria and viruses) present in the external environment. During breathing, these irritants travel through the bronchi and bronchioles to reach the deeper lung containing the alveoli, which constitute the minimal functional respiratory units. The local biological responses in the alveoli that follow introduction of irritants need to be tightly controlled in order to prevent a massive inflammatory response leading to loss of respiratory function. Cells, cytokines, chemokines and growth factors intervene collectively to re-establish tissue homeostasis, fight the aggression and replace the apoptotic/necrotic cells with healthy cells through proliferation and/or differentiation. Among the important growth factors at play during inflammation, members of the fibroblast growth factor (Fgf) family regulate the repair process. Fgf10 is known to be a key factor for organ morphogenesis and disease. Inflammation is influenced by Fgf10 but can also impact Fgf10 expression per se. Unfortunately, the connection between Fgf10 and inflammation in organogenesis and disease remains unclear. The aim of this review is to highlight the reported players between Fgf10 and inflammation with a focus on the lung and to propose new avenues of research.

Association of Circulating Vascular Endothelial Growth Factor Levels With Autoimmune Diseases: A Systematic Review and Meta-Analysis

Background

Autoimmune diseases (ADs) are characterized by immune-mediated tissue damage, in which angiogenesis is a prominent pathogenic mechanism. Vascular endothelial growth factor (VEGF), an angiogenesis modulator, is significantly elevated in several ADs including rheumatoid arthritis (RA), systemic sclerosis (SSc), and systemic lupus erythematosus (SLE). We determined whether circulating VEGF levels were associated with ADs based on pooled evidence.

Methods

The analyses included 165 studies from the PubMed, EMBASE, Cochrane Library, and Web of Science databases and fulfilled the study criteria. Comparisons of circulating VEGF levels between patients with ADs and healthy controls were performed by determining pooled standard mean differences (SMDs) with 95% confidence intervals (CIs) in a random-effect model using STATA 16.0. Subgroup, sensitivity, and meta-regression analyses were performed to determine heterogeneity and to test robustness.

Results

Compared with healthy subjects, circulating VEGF levels were significantly higher in patients with SLE (SMD 0.84, 95% CI 0.25-1.44, P = 0.0056), RA (SMD 1.48, 95% CI 0.82-2.15, P <0.0001), SSc (SMD 0.56, 95% CI 0.36-0.75, P <0.0001), Behcet's disease (SMD 1.65, 95% CI 0.88-2.41, P <0.0001), Kawasaki disease (SMD 2.41, 95% CI 0.10-4.72, P = 0.0406), ankylosing spondylitis (SMD 0.78, 95% CI 0.23-1.33, P = 0.0052), inflammatory bowel disease (SMD 0.57, 95% CI 0.43-0.71, P <0.0001), psoriasis (SMD 0.98, 95% CI 0.62-1.34, P <0.0001), and Graves' disease (SMD 0.69, 95% CI 0.20-1.19, P = 0.0056). Circulating VEGF levels correlated with disease activity and hematological parameters in ADs.

Conclusion

Circulating VEGF levels were associated with ADs and could predict disease manifestations, severity and activity in patients with ADs.

Systematic Review Registration

PROSPERO, identifier CRD42021227843.

Expression Analysis of FGF/FGFR and FOX Family Proteins in Mucosal Tissue Obtained from Orofacial Cleft-Affected Children

Orofacial clefts affect hundreds of thousands of children worldwide annually and are usually corrected by a series of surgeries extending to childhood. The underlying mechanisms that lead to clefts are still unknown, mainly because of the multifactorial etiology and the myriad of interactions between genes and environmental factors. In the present study, we investigated the role and expression of candidate genes belonging to the FGF/FGFR signaling pathway and FOX family in tissue material obtained from 12 pediatric patients undergoing cleft correction surgery. The expression was investigated using immunohistochemistry (IHC) and chromogenic in-situ hybridization (CISH) in three cell/tissue types-epithelial cells, connective tissue, and endothelial cells. We found elevated expression of FGFR1 in epithelial cells while no expression was observed in endothelial cells. Further, our results elucidate the potential pathogenetic role of FGFR1 in cellular proliferation, local site inflammation, and fibrosis in cleft patients. Along with bFGF (also called FGF2), FGFR1 could play a pro-inflammatory role in clefts. Over-amplification of FGFR2 in some patients, along with bFGF, could potentially suggest roles for these genes in angiogenesis. Additionally, increased expression of FOXE1 (also called TTF2) contributes to local site inflammation. Finally, zero to low amplification of FOXO1 could suggest its potential role in inducing oxidative stress in the endothelium along with reduced epithelial apoptosis.

Role of bFGF in Acquired Resistance upon Anti-VEGF Therapy in Cancer

Anti-angiogenic approaches targeting the vascular endothelial growth factor (VEGF) signaling pathway have been a significant research focus during the past decades and are well established in clinical practice. Despite the expectations, their benefit is ephemeral in several diseases, including specific cancers. One of the most prominent side effects of the current, VEGF-based, anti-angiogenic treatments remains the development of resistance, mostly due to the upregulation and compensatory mechanisms of other growth factors, with the basic fibroblast growth factor (bFGF) being at the top of the list. Over the past decade, several anti-angiogenic approaches targeting simultaneously different growth factors and their signaling pathways have been developed and some have reached the clinical practice. In the present review, we summarize the knowledge regarding resistance mechanisms upon anti-angiogenic treatment, mainly focusing on bFGF. We discuss its role in acquired resistance upon prolonged anti-angiogenic treatment in different tumor settings, outline the reported resistance mechanisms leading to bFGF upregulation, and summarize the efforts and outcome of combined anti-angiogenic approaches to date.

Formononetin inhibits inflammation and promotes gastric mucosal angiogenesis in gastric ulcer rats through regulating NF-κB signaling pathway

To investigate the effects of formononetin on rats with gastric ulcer and further to explore its possible mechanism. Rats were randomly divided into sham operation group (Sham), model group (Model), omeprazole control group (Omeprazole) and formononetin in different dose groups (FOR-L, FOR-M, FOR-H). Rats model with gastric ulcer were established by 100% glacial acetic acid. Hematoxylin-eosin (H&E) staining was used to observe the pathological morphology of gastric mucosa. Immunohistochemistry and enzyme-linked immunosorbent assay (ELISA) were used to detect the level of inflammatory and angiogenesis related factors. The expressions of nuclear factor kappa-B (NF-κB) signaling pathway-related proteins were detected by western blot. Formononetin and omeprazole could ameliorate the pathological morphology of gastric mucosa in gastric ulcer rats. Compared with Model group, the levels of tumor necrosis factor (TNF)-α, Interleukin (IL)-1β, IL-6, myeloperoxidase (MPO), human endothelin (ET)-1 and p-P65 protein in formononetin treatment and omeprazole groups were significantly decreased (p < 0.05). Moreover, formononetin could increase the content of vascular endothelial growth factor (VEGF), nitric oxide (NO) and the levels of CD34, tight junction proteins (ZO-1 and occludin) and p-IκBα in a dose-dependent manner. Formononetin can ameliorate gastric ulcer in rats by inhibiting inflammation and promoting gastric mucosal angiogenesis, and its mechanism maybe related to NF-κB signaling pathway.

Experimental and Clinical Evidence of Endothelial Dysfunction in Inflammatory Bowel Disease

The endothelium has a crucial role in proper hemodynamics. Inflammatory bowel disease (IBD) is mainly a chronic inflammatory condition of the gastrointestinal tract. However, considerable evidence points to high cardiovascular risk in patients with IBD. This review positions the basic mechanisms of endothelial dysfunction in the IBD setting (both clinical and experimental). Furthermore, we review the main effects of drugs used to treat IBD in endothelial (dys)function. Moreover, we leave challenging points for enlarging the therapeutic arsenal for IBD with new or repurposed drugs that target endothelial dysfunction besides inflammation.

Clinical Significance of Hepatocyte Growth Factor and Transforming Growth Factor-Beta-1 Levels in Assessing Disease Activity in Inflammatory Bowel Disease

Background. Transforming growth factor-beta (TGF-β) and hepatocyte growth factor (HGF) are inflammatory cytokines which function as key regulators of immunological homeostasis and inflammatory responses. They have been linked to inflammatory bowel diseases (IBD). In this study, we aim to assess the levels of TGF-β and HGF and other inflammatory markers in patients with IBD and correlate them with the disease activity. Study Design. A cross-sectional study involving 100 patients with ulcerative colitis (UC) and 100 patients with Crohn's disease (CD) and 50 control subjects. TGF-β and HGF levels were measured and correlated with disease activity. Results and Conclusion. Serum levels of TGF-β and HGF were significantly higher in IBD patients compared with the control group. In the UC group, the levels of HGF and TGF-β were significantly higher than in the CD group. Levels of TGF-β and HGF correlate with the activity of IBD.

The Relationship between Ocular Vascular Changes and the Levels of Malondialdehyde and Vascular Endothelial Growth Factor in Patients with Inflammatory Bowel Disease

Background: We evaluated ocular hemodynamic changes, malondialdehyde(MDA) and vascular endothelial growth factor (VEGF) levels in patients with IBD.Methods: We used ocular color Doppler ultrasonography to analyze 56 eyes with Crohn's disease (CD), 62 eyes with ulcerative colitis (UC), 68 eyes of healthy volunteers. We measured peak systolic velocity (PSV),end-diastolic velocity (EDV),and the resistivity index (RI) of ophthalmic artery (OA) and central retinal artery (CRA). MDA and VEGF levels were measured in the plasma samples.Results: MDA levels were significantly higher in both UC and CD patients, whereas VEGF levels were only higher in the CD group (p = .003,p < .001,p = .01).The PSV and EDV of the OA were significantly lower in CD patients (p = .017,p = .001). The EDV of the CRA was significantly lower in CD patients than UC patients and controls (p = .014,p < .001).Conclusions: CD patients exhibited decreased blood flow in both the OA and CRA. Ocular vascular flow was only affected in CD patients. We found that ocular ischemia may occur in CD patients even in the absence of any clinical finding.

Mucosal gene transcription of ulcerative colitis in endoscopic remission

Aim/Objective: Ulcerative colitis (UC) is a chronic inflammatory bowel disease. In UC, a wide range of criteria are used for disease remission, with few studies investigating the differences between disease remission and normal control groups. This paper compares known inflammatory and healing mediators in the mucosa of UC in clinical remission and normal controls, in order to better describe the remission state.Method: Mucosal biopsies from 72 study participants (48 UC and 24 normal controls) were included from the Advanced Study of Inflammatory Bowel Disease (ASIB Study), Arctic University of Norway, Norway. Clinical remission was defined as Mayo clinical score ≤ 2, with endoscopic subscores of ≤ 1. Targeted gene transcription analyses were performed using hydrolysis probes and SYBR-green.Results: Among the mucosal transcripts examined, 10 genes were regulated in remission versus normal controls, 8 upregulated pro-inflammatory transcripts (IL1B, IL33, TNF, TRAF1, CLDN2, STAT1, STAT3 and IL13Ra2) and 2 downregulated (pro-inflammatory TBX21 and anti-inflammatory TGFB1). In total, 14 transcripts were regulated between the investigated groups. Several master transcription factors for T-cell development were upregulated in patients with Mayo endoscopic score of 1 in comparison to 0.Conclusions: The mucosa of UC in clinical and endoscopic remission differs from normal mucosa, suggesting a remaining dysregulation of inflammatory and wound healing mechanisms.

G protein-coupled estrogen receptor mediates anti-inflammatory action in Crohn's disease

Estrogens exert immunomodulatory action in many autoimmune diseases. Accumulating evidence highlights the meaningful impact of estrogen receptors in physiology and pathophysiology of the colon. However, the significance of G protein-coupled estrogen receptor (GPER) on Crohn's disease (CD), one of the inflammatory bowel disease (IBD) types, is still elusive. Our study revealed GPER overexpression at the mRNA and protein levels in patients with CD. To evaluate the effects of GPER activation/inhibition on colitis development, a murine 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced model of CD was used. We showed that activation of GPER reduces mortality, improves macroscopic and microscopic scores and lowers C-reactive protein (CRP) level. The impact of estrogen signaling on the suppression of the intestinal inflammation was proved by immunohistochemistry. It was demonstrated that GPER activation is accompanied by modulation of extracellular-signal regulated kinase (ERK) signaling pathway and expression level of genes involved in signal transmission and immune response as well as the expression of some microRNAs (miR-145, miR-148-5p and miR-592). Our study revealed that the membrane-bound estrogen receptor GPER mediates anti-inflammatory action and seems to be a potent therapeutic target in maintaining remission in CD.

Clostridium difficile toxins induce VEGF-A and vascular permeability to promote disease pathogenesis

Clostridium difficile infection (CDI) is mediated by two major exotoxins, toxin A (TcdA) and toxin B (TcdB), that damage the colonic epithelial barrier and induce inflammatory responses. The function of the colonic vascular barrier during CDI has been relatively understudied. Here we report increased colonic vascular permeability in CDI mice and elevated vascular endothelial growth factor A (VEGF-A), which was induced in vivo by infection with TcdA- and/or TcdB-producing C. difficile strains but not with a TcdA^-TcdB^- isogenic mutant. TcdA or TcdB also induced the expression of VEGF-A in human colonic mucosal biopsies. Hypoxia-inducible factor signalling appeared to mediate toxin-induced VEGF production in colonocytes, which can further stimulate human intestinal microvascular endothelial cells. Both neutralization of VEGF-A and inhibition of its signalling pathway attenuated CDI in vivo. Compared to healthy controls, CDI patients had significantly higher serum VEGF-A that subsequently decreased after treatment. Our findings indicate critical roles for toxin-induced VEGF-A and colonic vascular permeability in CDI pathogenesis and may also point to the pathophysiological significance of the gut vascular barrier in response to virulence factors of enteric pathogens. As an alternative to pathogen-targeted therapy, this study may enable new host-directed therapeutic approaches for severe, refractory CDI.

Moonlighting Activity of Secreted Inflammation-Regulatory Proteins

Moonlighting proteins exhibit multiple activities in different cellular compartments, and their abnormal regulation could play an important role in many diseases. To date, many proteins have been identified with moonlighting activity, and more such proteins are being gradually identified. Among the proteins that possess moonlighting activity, several secreted proteins exhibit multiple activities in different cellular locations, such as the extracellular matrix, nucleus, and cytoplasm. While acute inflammation starts rapidly and generally disappears in a few days, chronic inflammation can last for months or years. This is generally because of the failure to eliminate the cause of inflammation, along with repeated exposure to the inflammatory agent. Chronic inflammation is now considered as an overwhelming burden to the general wellbeing of patients and noted as an underlying cause of several diseases. Moonlighting proteins can contribute to the process of chronic inflammation; therefore, it is imperative to overview some proteins that exhibit multiple functions in inflammatory diseases. In this review, we will focus on inflammation, particularly unravelling several well-known secreted proteins with multiple functions in different cellular locations.

Colitic Cancer Develops Through Mutational Alteration Distinct from that in Sporadic Colorectal Cancer: A Comparative Analysis of Mutational Rates at Each Step

BACKGROUND

Patients with ulcerative colitis (UC) are at risk of UC-associated colorectal cancer (CRC); however, little is known about genetic alterations occurring during UC carcinogenesis. We examined mutational changes in patients with colitic cancer and the features that differed between the carcinogenesis of UC and sporadic CRC.

MATERIAL AND METHODS

Specimens were obtained from the non-neoplastic mucosa and cancer cells of 12 patients with colitic cancer. The mutational rate of oncogenes in colitic cancer was analyzed and compared to that of oncogenes in sporadic CRC.

RESULTS

We observed a lower mutation rate in adenomatous polyposis coli (APC) (16.7%(2/12) vs. 75.9%(161/212), respectively, p=0.0001) and KRAS (16.7%(2/12) vs. 42% (89/212), respectively, p=0.04) in colitic cancer than in sporadic CRC. With respect to cadherin 1 (CDH1) and fibroblast growth factor receptor 2 (FGFR2), the mutational rates for non-neoplastic colorectal mucosa were similar to those in sporadic CRC.

CONCLUSION

We demonstrated that mutational rates for APC and KRAS differ between colitic cancer and sporadic CRC. Furthermore, we revealed that CDH1 and FGFR2 become mutated at an earlier stage in colitic carcinogenesis than in sporadic CRC.

Chronic inflammation - inflammaging - in the ageing cochlea: A novel target for future presbycusis therapy

Chronic, low-grade inflammation, or inflammaging, is a crucial contributor to various age-related pathologies and natural processes in aging tissue, including the nervous system. Over the past two decades, much effort has been done to understand the mechanisms of inflammaging in disease models such as type II diabetes, cardiovascular disease, Alzheimer's disease, Parkinson's disease, and others. However, despite being the most prevalent neurodegenerative disorder, the number one communication disorder, and one of the top three chronic medical conditions of our aged population; little research has been conducted on the potential role of inflammation in age-related hearing loss (ARHL). Recently, it has been suggested that there is an inflammatory presence in the cochlea, perhaps involving diffusion processes of the blood-brain barrier as it relates to the inner ear. Recent research has found correlations between hearing loss and markers such as C-reactive protein, IL-6, and TNF-α indicating inflammatory status in human case-cohort studies. However, there have been very few reports of in vivo research investigating the role of chronic inflammation's in hearing loss in the aging cochlea. Future research directed at better understanding the mechanisms of inflammation in the cochlea as well as the natural changes acquired with aging may provide a better understanding of how this process can accelerate presbycusis. Animal model experimentation and pre-clinical studies designed to recognize and characterize cochlear inflammatory mechanisms may suggest novel treatment strategies for preventing or treating ARHL. In this review, we seek to summarize key research in chronic inflammation, discuss its implications for possible roles in ARHL, and finally suggest directions for future investigations.

Effect of Niacin on Inflammation and Angiogenesis in a Murine Model of Ulcerative Colitis

Butyrate and niacin are produced by gut microbiota, however butyrate has received most attention for its effects on colonic health. The present study aimed at exploring the effect of niacin on experimental colitis as well as throwing some light on the ability of niacin to modulate angiogenesis which plays a crucial role of in the pathogenesis of inflammatory bowel disease. Rats were given niacin for 2 weeks. On day 8, colitis was induced by intrarectal administration of iodoacetamide. Rats were sacrificed on day 15 and colonic damage was assessed macroscopically and histologically. Colonic myeloperoxidase (MPO), tumour necrosis factor (TNF)-α, interleukin (IL)-10, vascular endothelial growth factor (VEGF), angiostatin and endostatin levels were determined. Niacin attenuated the severity of colitis as demonstrated by a decrease in weight loss, colonic wet weight and MPO activity. Iodoacetamide-induced rise in the colonic levels of TNF-α, VEGF, angiostatin and endostatin was reversed by niacin. Moreover, niacin normalized IL-10 level in colon. Mepenzolate bromide, a GPR109A receptor blocker, abolished the beneficial effects of niacin on body weight, colon wet weight as well as colonic levels of MPO and VEGF. Therefore, niacin was effective against iodoacetamide-induced colitis through ameliorating pathologic angiogenesis and inflammatory changes in a GPR109A-dependent manner.

Synergic modulation of the inflammatory state of macrophages utilizing anti-oxidant and phosphatidylserine-containing polymer-lipid hybrid nanoparticles

Inflammatory activation of macrophages is a key factor in chronic inflammatory diseases such as ulcerative colitis. The excessive production of reactive oxygen species (ROS)/reactive nitrogen species (RNS) by macrophages causes oxidative stress during the inflammatory response and exaggerates inflammatory lesions in ulcerative colitis. Inhibition of the inflammatory activation of macrophages is a promising treatment for chronic inflammatory diseases. Here, we prepared self-filling polymer-lipid hybrid nanoparticles (PST-PLNPs) consisting of poly dl-lactic acid as a hydrophobic biodegradable polymer core encapsulating α-tocopherol (T) and phosphatidylserine (PS) both on the surface and interior of the particle. We confirmed the anti-inflammatory response of these hybrid nanoparticles in activated murine macrophages. PS has anti-inflammatory effects on macrophages by modulating the macrophage phenotype, while α-tocopherol is an antioxidant that neutralizes ROS. We found that PS-containing (PS-PLNPs) and PS plus α-tocopherol-containing (PST-PLNPs) polymer-lipid hybrid nanoparticles significantly increased the viability of lipopolysaccharide (LPS)-treated macrophages compared with phosphatidylcholine-containing PLNPs. PST-PLNPs had a better effect than PS-PLNPs, which was attributed to the synergy between PS and α-tocopherol. This synergic action of PST-PLNPs reduced NO and pro-inflammatory cytokine (IL-6) production and increased anti-inflammatory cytokine (TGF-β1) production when incubated with activated macrophages. Thus, these self-filling biodegradable polymer-lipid hybrid nanoparticles (PST-PLNPs) containing anti-oxidant and anti-inflammatory molecules might be potential alternative drug carriers to liposomes and polymeric nanoparticles for the treatment of chronic inflammatory diseases such as ulcerative colitis.

TGF-β in inflammatory bowel disease: a key regulator of immune cells, epithelium, and the intestinal microbiota

Inflammatory bowel disease (IBD) is defined as chronic intestinal inflammation, and includes ulcerative colitis and Crohn's disease. Multiple factors are involved in the pathogenesis of IBD, and the condition is characterized by aberrant mucosal immune reactions to intestinal microbes in genetically susceptible hosts. Transforming growth factor-β (TGF-β) is an immune-suppressive cytokine produced by many cell types and activated by integrins. Active TGF-β binds to its receptor and regulates mucosal immune reactions through the TGF-β signaling pathway. Dysregulated TGF-β signaling is observed in the intestines of IBD patients. TGF-β signal impairment in specific cell types, such as T-cells and dendritic cells, results in spontaneous colitis in mouse models. In addition, specific intestinal microbes contribute to immune homeostasis by modulating TGF-β production. In this review, we describe the role of TGF-β in intestinal immunity, focusing on immune cells, epithelium, and intestinal microbes. In addition, we present potential therapeutic strategies for IBD that target TGF-β.

Effects of indigo naturalis on colonic mucosal injuries and inflammation in rats with dextran sodium sulphate-induced ulcerative colitis

The effects of indigo naturalis (IN), which is a traditional Chinese herbal formulation, have been clinically demonstrated in treating refractory ulcerative colitis (UC). The present study aimed to verify the effects and mechanisms of IN in experimental UC rats. A total of 48 male Sprague-Dawley rats were randomly divided into six groups: Chow, model, high-dose IN, medium-dose IN, low-dose IN and mesalazine (a bowel-specific aminosalicylate drug) groups. The models were administered 3.5% dextran sodium sulphate solution for 7 days. The treatment groups were administered IN or mesalazine and then sacrificed and sampled on day 8. Disease activity index (DAI), histological damage score (HDS) and myeloperoxidase (MPO) activity were used to evaluate the severity of UC. Colon and serum cytokines were detected using liquid-phase chip technology and the expression of occludin protein in colonic mucosa was assessed by immunohistochemistry and western blot analysis. The results indicated that the oral administration of IN may reduce DAI, HDS and MPO activity. IN also reduced the expression of inflammatory cytokines and increased the expression of colonic mucosal repair-related cytokines and occludin protein. These results highlight the potential of IN as a therapeutic agent for treating UC through its action of inflammation control and colonic mucosal damage repair.

Genome-wide Association Study Identifies 27 Loci Influencing Concentrations of Circulating Cytokines and Growth Factors

Circulating cytokines and growth factors are regulators of inflammation and have been implicated in autoimmune and metabolic diseases. In this genome-wide association study (GWAS) of up to 8,293 Finns we identified 27 genome-widely significant loci (p < 1.2 × 10^-9) for one or more cytokines. Fifteen of the associated variants had expression quantitative trait loci in whole blood. We provide genetic instruments to clarify the causal roles of cytokine signaling and upstream inflammation in immune-related and other chronic diseases. We further link inflammatory markers with variants previously associated with autoimmune diseases such as Crohn disease, multiple sclerosis, and ulcerative colitis and hereby elucidate the molecular mechanisms underpinning these diseases and suggest potential drug targets.

Potential role for ET-2 acting through ETA receptors in experimental colitis in mice

OBJECTIVE AND DESIGN

This study attempted to clarify the roles of endothelins and mechanisms associated with ET_A/ET_B receptors in mouse models of colitis.

MATERIALS AND METHODS

Colitis was induced by intracolonic administration of 2,4,6-trinitrobenzene sulfonic acid (TNBS, 1.5 mg/animal) or dextran sulfate sodium (DSS, 3%). After colitis establishment, mice received Atrasentan (ET_A receptor antagonist, 10 mg/kg), A-192621 (ET_B receptor antagonist, 20 mg/kg) or Dexamethasone (1 mg/kg) and several inflammatory parameters were assessed, as well as mRNA levels for ET-1, ET-2 and ET receptors.

RESULTS

Atrasentan treatment ameliorates TNBS- and DSS-induced colitis. In the TNBS model was observed reduction in macroscopic and microscopic score, colon weight, neutrophil influx, IL-1β, MIP-2 and keratinocyte chemoattractant (KC) levels, inhibition of adhesion molecules expression and restoration of IL-10 levels. However, A192621 treatment did not modify any parameter. ET-1 and ET-2 mRNA was decreased 24 h, but ET-2 mRNA was markedly increased at 48 h after TNBS. ET-2 was able to potentiate LPS-induced KC production in vitro. ET_A and ET_B receptors mRNA were increased at 24, 48 and 72 h after colitis induction.

CONCLUSIONS

Atrasentan treatment was effective in reducing the severity of colitis in DSS- and TNBS-treated mice, suggesting that ET_A receptors might be a potential target for inflammatory bowel diseases.

Angiogenesis in Inflammatory Bowel Disease

Angiogenesis is an important component of pathogenesis of inflammatory bowel disease (IBD). Chronic inflammation and angiogenesis are two closely related processes. Chronic intestinal inflammation is dependent on angiogenesis and this angiogenesis is modulated by immune system in IBD. Angiogenesis is a very complex process which includes multiple cell types, growth factors, cytokines, adhesion molecules, and signal transduction. Lymphangiogenesis is a new research area in the pathogenesis of IBD. While angiogenesis supports inflammation via leukocyte migration, carrying oxygen and nutrients, on the other hand, it has a major role in wound healing. Angiogenic molecules look like perfect targets for the treatment of IBD, but they have risk for serious side effects because of their nature.

The Insect Peptide CopA3 Increases Colonic Epithelial Cell Proliferation and Mucosal Barrier Function to Prevent Inflammatory Responses in the Gut

The epithelial cells of the gut form a physical barrier against the luminal contents. The collapse of this barrier causes inflammation, and its therapeutic restoration can protect the gut against inflammation. EGF enhances mucosal barrier function and increases colonocyte proliferation, thereby ameliorating inflammatory responses in the gut. Based on our previous finding that the insect peptide CopA3 promotes neuronal growth, we herein tested whether CopA3 could increase the cell proliferation of colonocytes, enhance mucosal barrier function, and ameliorate gut inflammation. Our results revealed that CopA3 significantly increased epithelial cell proliferation in mouse colonic crypts and also enhanced colonic epithelial barrier function. Moreover, CopA3 treatment ameliorated Clostridium difficile toxin As-induced inflammation responses in the mouse small intestine (acute enteritis) and completely blocked inflammatory responses and subsequent lethality in the dextran sulfate sodium-induced mouse model of chronic colitis. The marked CopA3-induced increase of colonocyte proliferation was found to require rapid protein degradation of p21(Cip1/Waf1), and an in vitro ubiquitination assay revealed that CopA3 directly facilitated ubiquitin ligase activity against p21(Cip1/Waf1). Taken together, our findings indicate that the insect peptide CopA3 prevents gut inflammation by increasing epithelial cell proliferation and mucosal barrier function.

A zebrafish model of inflammatory lymphangiogenesis

Inflammatory bowel disease (IBD) is a disabling chronic inflammatory disease of the gastrointestinal tract. IBD patients have increased intestinal lymphatic vessel density and recent studies have shown that this may contribute to the resolution of IBD. However, the molecular mechanisms involved in IBD-associated lymphangiogenesis are still unclear. In this study, we established a novel inflammatory lymphangiogenesis model in zebrafish larvae involving colitogenic challenge stimulated by exposure to 2,4,6-trinitrobenzenesulfonic acid (TNBS) or dextran sodium sulphate (DSS). Treatment with either TNBS or DSS resulted in vascular endothelial growth factor receptor (Vegfr)-dependent lymphangiogenesis in the zebrafish intestine. Reduction of intestinal inflammation by the administration of the IBD therapeutic, 5-aminosalicylic acid, reduced intestinal lymphatic expansion. Zebrafish macrophages express vascular growth factors vegfaa, vegfc and vegfd and chemical ablation of these cells inhibits intestinal lymphatic expansion, suggesting that the recruitment of macrophages to the intestine upon colitogenic challenge is required for intestinal inflammatory lymphangiogenesis. Importantly, this study highlights the potential of zebrafish as an inflammatory lymphangiogenesis model that can be used to investigate the role and mechanism of lymphangiogenesis in inflammatory diseases such as IBD.

Id1 expression in endothelial cells of the colon is required for normal response to injury

Inhibitor of DNA binding (ID)-1 is important for angiogenesis during embryogenesis and tumor development. Whether ID1 expression in endothelial cells of the colon is required for normal response to injury is unknown. We demonstrate that Id1 is up-regulated in colonic endothelial cells in an experimental model of colitis and in the inflamed mucosa of patients with inflammatory bowel disease. Because prostaglandin E2 and tumor necrosis factor-α are also elevated in colitis, we determined whether these factors could induce ID1 transcription in cultured endothelial cells. Tumor necrosis factor-α stimulated ID1 transcription via early growth response 1 protein (Egr-1). By contrast, the induction of ID1 by prostaglandin E2 was mediated by cAMP response element-binding protein (CREB). To determine whether the increased ID1 levels in the endothelial cells of inflamed mucosa were an adaptive response that modulated the severity of tissue injury, Id1 was conditionally depleted in the endothelium of mice, which sensitized the mice to more severe chemical colitis, including more severe diarrhea, bleeding, and histological injury, and shorter colon compared with control mice. Moreover, depletion of Id1 in the vasculature was associated with increased CD31(+) aggregates and increased vascular permeability in inflamed mucosa compared with those in Id1 wild-type control mice. These results suggest that endothelial ID1 up-regulation in inflamed colonic mucosa is an adaptive response that modulates the severity of tissue injury.

Hepatoprotective and anti-tumor effects of targeting MMP-9 in hepatocellular carcinoma and its relation to vascular invasion markers

The current study aims to evaluate the hepatoprotective and antitumor efficacy of doxycycline, as an matrix metalloproteases-9 (MMP-9) inhibitor, in an in vivo model of hepatocellular carcinoma (HCC). HCC was induced experimentally by thiocetamide (200 mg/kg) in rats that were treated with doxycycline (5 mg/kg for 16 weeks). Tumor severity was evaluated by measuring α-fetoprotein (AFP) levels, histopathologically by investigating liver sections stained with hematoxylin/eosin and assessing the survival rate. Liver homogenates were used for the measurements of MMP-9, fascin and hepatic heparan sulfate proteoglycan (HSPG) levels. Oxidative stress markers [malonaldehyde (MDA) and glutathione] as well as fibroblast growth factor-2 (FGF-2) gene expression were also among the assessed indicators. HCC in human and animal samples showed significant elevation in the levels of MMP-9 (231.7, 90 %), fascin (33.17, 140 %), as well as FGF-2 gene expression (342 % in animal samples; all respectively), associated with a significant decrease in hepatic HSPG level. Treatment of rats with doxycycline increased the animal survival rate (90 %) and decreased serum AFP level. Moreover, doxycycline ameliorated fibrosis and the induced massive hepatic tissue breakdown. It also restored the integrity of hepatic HSPGs and showed a magnificent inhibitory effect of tumor invasion cascade by significantly reducing the activities of MMP-9 (42 %) and fascin (50 %), as well as reducing the gene expression of FGF-2 (85.7 %). Furthermore, the antioxidant impact of doxycycline was evidenced by the significant elevation in glutathione level and depressing MDA level. To this end, doxycycline, proved promising hepatoprotective and antitumor activity and opens, thereby, a new horizon against vascular migration ability of the tumor cells.

Diacetyloxyl derivatization of the fibroblast growth factor inhibitor dobesilate enhances its anti-inflammatory, anti-angiogenic and anti-tumoral activities

BACKGROUND

Dobesilate (2,5-dihydroxyphenyl sulfonate, DHPS) was recently identified as the most potent member of a family of fibroblast growth factor (FGF) inhibitors headed by gentisic acid, one of the main catabolites of aspirin. Although FGFs were first described as inducers of angiogenesis, they were soon recognized as broad spectrum mitogens. Furthermore, in the last decade these proteins have been shown to participate directly in the onset of inflammation, and their potential angiogenic activity often contributes to the inflammatory process in vivo. The aim of this work was to evaluate the anti-inflammatory, anti-angiogenic and anti-tumoral activities of the derivative of DHPS obtained by acetoxylation of its two hydroxyl groups (2,5-diacetoxyphenyl sulfonate; DAPS).

METHODS

Anti-inflammatory, anti-angiogenic and anti-tumoral activities of DHPS and DAPS were compared using in vivo assays of dermatitis, angiogenesis and tumorigenesis. The effects of both compounds on myeloperoxidase (MPO) and cyclooxygenase (COX) activities, cytokine production and FGF-induced fibroblast proliferation were also determined.

RESULTS

Topical DAPS is more effective than DHPS in preventing inflammatory signs (increased vascular permeability, edema, leukocyte infiltration, MPO activation) caused by contact dermatitis induction in rat ears. DAPS, but not DHPS, effectively inhibits COX-1 and COX-2 activities. DAPS also reduces the increase in serum cytokine concentration induced by lipopolysaccharide in rats. Furthermore, DAPS displays higher in vivo efficacy than DHPS in inhibiting FGF-induced angiogenesis and heterotopic glioma progression, with demonstrated oral efficacy to combat both processes.

CONCLUSIONS

By inhibiting both FGF-signaling and COX-mediated prostaglandin synthesis, DAPS efficiently breaks the vicious circle created by the reciprocal induction of FGF and prostaglandins, which probably sustains undesirable inflammation in many circumstances. Our findings define the enhancement of anti-inflammatory, anti-angiogenic and anti-tumoral activities by diacetyloxyl derivatization of the FGF inhibitor, dobesilate.

Endothelin and vascular remodelling in colitis pathogenesis--appendicitis and appendectomy limit colitis by suppressing endothelin pathways

PURPOSE

Appendicitis and appendectomy(AA), when done at a young age, offer protection against inflammatory bowel disease (IBD) development in later life. However, IBD pathogenesis involves both immunological and vascular abnormalities. Using the first murine model of AA (developed by us), we aimed to determine the role of AA in modulating vascular remodelling mediated by endothelin activity in IBD.

METHODS

Mice with two laparotomies each served as controls (sham-sham or SS). Distal colons were harvested (four AA group colons, four SS group colons), and RNA extracted from each. The RNA was subjected to microarray analysis and RT-PCR validation. Gene set enrichment analysis (GSEA) software was used to further analyze the microarray data.

RESULTS

Gene expression of seven genes closely associated with endothelin activity was examined in distal colons 3 days post-AA and 28 days post-AA. While there were no gene expression changes 3 days post-AA, the genes EDN1 (0.7-fold), EDN2 (0.8-fold) and ECE2 (0.8-fold) were downregulated (*p value <0.05) 28 days post-AA. However, EDN3 (1.3-fold) was upregulated 28 days post-AA (*p value <0.05). GSEA analysis showed downregulation of 11 gene sets (stringent cut-offs-false discovery rate <5 % and p value <0.001) associated with endothelin and endothelin-converting enzyme genes by AA, in contrast to only 1 being upregulated.

CONCLUSIONS

AA induces a delayed but significant suppression of genes pertaining to endothelin activity. Elucidating the pathways involved in suppression of endothelin activity and manipulation of different genes/enzymes/proteins related to endothelin activity will significantly enhance the extant repertoire of therapeutic options in IBD.

The neurotensin-HIF-1α-VEGFα axis orchestrates hypoxia, colonic inflammation, and intestinal angiogenesis

The expression of neurotensin (NT) and its receptor (NTR1) is up-regulated in experimental colitis and inflammatory bowel disease; NT/NTR1 interactions regulate gut inflammation. During active inflammation, metabolic shifts toward hypoxia lead to the activation of hypoxia-inducible factor (HIF)-1, which enhances vascular endothelial growth factor (VEGF) expression, promoting angiogenesis. We hypothesized that NT/NTR1 signaling regulates intestinal manifestations of hypoxia and angiogenesis by promoting HIF-1 transcriptional activity and VEGFα expression in experimental colitis. We studied NTR1 signaling in colitis-associated angiogenesis using 2,4,6-trinitrobenzenesulfonic acid-treated wild-type and NTR1-knockout mice. The effects of NT on HIF-1α and VEGFα were assessed on human colonic epithelial cells overexpressing NTR1 (NCM460-NTR1) and human intestinal microvascular-endothelial cells. NTR1-knockout mice had reduced microvascular density and mucosal integrity score compared with wild-type mice after 2,4,6-trinitrobenzenesulfonic acid treatment. VEGFα mRNA levels were increased in NCM460-NTR1 cells treated with 10(-7) mol/L NT, at 1 and 6 hours post-treatment. NT exposure in NCM460-NTR1 cells caused stabilization, nuclear translocation, and transcriptional activity of HIF-1α in a diacylglycerol kinase-dependent manner. NT did not stimulate tube formation in isolated human intestinal macrovascular endothelial cells but did so in human intestinal macrovascular endothelial cells cocultured with NCM460-NTR1 cells. Our results demonstrate the importance of an NTR1-HIF-1α-VEGFα axis in intestinal angiogenic responses and in the pathophysiology of colitis and inflammatory bowel disease.

Evidence for the endothelin system as an emerging therapeutic target for the treatment of chronic pain

Many people worldwide suffer from pain and a portion of these sufferers are diagnosed with a chronic pain condition. The management of chronic pain continues to be a challenge, and despite taking prescribed medication for pain, patients continue to have pain of moderate severity. Current pain therapies are often inadequate, with side effects that limit medication adherence. There is a need to identify novel therapeutic targets for the management of chronic pain. One potential candidate for the treatment of chronic pain is therapies aimed at modulating the vasoactive peptide endothelin-1. In addition to vasoactive properties, endothelin-1 has been implicated in pain transmission in both humans and animal models of nociception. Endothelin-1 directly activates nociceptors and potentiates the effect of other algogens, including capsaicin, formalin, and arachidonic acid. In addition, endothelin-1 has been shown to be involved in inflammatory pain, cancer pain, neuropathic pain, diabetic neuropathy, and pain associated with sickle cell disease. Therefore, endothelin-1 may prove a novel therapeutic target for the relief of many types of chronic pain.

Increased serum VEGF and b-FGF in Graves' ophthalmopathy

Background

Graves’ ophthalmopathy (GO) is thought to be an inflammatory disorder of autoimmune background. The aim of this study is to investigate the involvement of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (b-FGF) in patients with Graves’ ophthalmopathy (GO).

Methods

Serum concentrations of VEGF and b-FGF of 48 GO patients, 30 Graves’ hyperthyroid disease (GD) patients without ophthalmopathy, and 30 healthy controls were measured by Enzyme-Linked Immunosorbent Assay (ELISA). Patients with GO were subdivided into two groups according to clinical activity scores (CAS): a score of 3 or less is considered as inactive (CAS ≤ 3, inactive GO, n = 14), and 4 or more is considered active eye disease (CAS ≥ 4, active GO; n = 34). All of the patients with active GO underwent corticosteroid therapy.

Results

The concentrations of serum VEGF and b-FGF were significantly higher in patients with GO and in those with GD than in controls. The serum levels of VEGF and b-FGF in patients with active GO were higher than those in patients with inactive GO and those in GD patients (P < 0.05). Moreover, serum VEGF and b-FGF concentratison were significantly correlated with CAS in GO patients (p < 0.01). Mean VEGF and b-FGF levels in corticosteroid-responsive patients (CAS decreases ≥3 after treatment) decreased significantly after corticosteroid treatment (P < 0.05), and these changes were accompanied by a decrease of CAS (P < 0.05).

Conclusion

The results suggest that serum VEGF and b-FGF levels were increased in patients with active GO and could reflect the degree of ocular inflammatory activity.

An important role of the SDF-1/CXCR4 axis in chronic skin inflammation

Inflammatory angiogenesis and vascular remodeling play key roles in the chronic inflammatory skin disease psoriasis, but little is known about the molecular mediators of vascular activation. Based on the reported elevated mRNA levels of the angiogenic chemokine stromal cell-derived factor-1 (SDF-1) and its receptor CXCR4 in psoriasis, we investigated the relevance of the SDF-1/CXCR4 axis in two experimental models of chronic psoriasis-like skin inflammation. The cutaneous expression of both SDF-1 and CXCR4 was upregulated in the inflamed skin of K14-VEGF-A transgenic mice and in imiquimod-induced skin inflammation, with expression of CXCR4 by blood vessels and macrophages. Treatment with the CXCR4 antagonist AMD3100 potently inhibited skin inflammation in both models, associated with reduced inflammatory angiogenesis and inflammatory cell accumulation, including dermal CD4+ cells and intraepidermal CD8+ T cells. Similar anti-inflammatory effects were seen after treatment with a neutralizing anti-SDF-1 antibody. In vitro, inhibition of CXCR4 blocked SDF-1-induced chemotaxis of CD11b+ splenocytes, in agreement with the reduced number of macrophages after in vivo CXCR4 blockade. Our results reveal an important role of the SDF-1/CXCR4 axis in skin inflammation and inflammatory angiogenesis, and they indicate that inhibition of the SDF-1/CXCR4 axis might serve as a novel therapeutic strategy for chronic inflammatory skin diseases.

Matrix metalloproteinase-9: its interplay with angiogenic factors in inflammatory bowel diseases

Matrix metalloproteinase- (MMP-) 9 is one of the main metalloproteinases reported to be involved in extracellular matrix degradation and recently also in triggering of angiogenic switch in the course of inflammatory bowel diseases (IBD). The goal of our studies was to estimate in one experimental setting the levels of MMP-9 in sera of Crohn's Disease (CD) and ulcerative colitis (UC) patients and to evaluate its possible diagnostic potential in comparison with other biochemical markers and selected proinflammatory and angiogenic factors. The study group included 176 subjects (CD = 64, UC = 85, control = 27). Concentrations of serum MMP-9 were significantly higher in active than inactive forms of IBD, being higher in active UC than in active CD. Both in the case of CD and UC serum MMP-9 positively correlated with disease activity, IL-6 levels, platelet and leukocyte count, midkine, and PDGF-BB, as well as in UC with ESR and in CD with CRP, IL-1, and VEGF-A. Diagnostic accuracy of MMP-9 in distinguishing active UC from active CD was 66%, and displayed higher specificity than CRP (79.0% versus 61.6%, resp.). Evaluation of serum MMP-9 concentrations could aid in differentiation of active UC from active CD. MMP-9 correlated better with inflammatory and angiogenic parameters in CD than in UC.

Repeated autologous bone marrow-derived mesenchymal stem cell injections improve radiation-induced proctitis in pigs

The management of proctitis in patients who have undergone very-high-dose conformal radiotherapy is extremely challenging. The fibrosis-necrosis, fistulae, and hemorrhage induced by pelvic overirradiation have an impact on morbidity. Augmenting tissue repair by the use of mesenchymal stem cells (MSCs) may be an important advance in treating radiation-induced toxicity. Using a preclinical pig model, we investigated the effect of autologous bone marrow-derived MSCs on high-dose radiation-induced proctitis. Irradiated pigs received repeated intravenous administrations of autologous bone marrow-derived MSCs. Immunostaining and real-time polymerase chain reaction analysis were used to assess the MSCs' effect on inflammation, extracellular matrix remodeling, and angiogenesis, in radiation-induced anorectal and colon damages. In humans, as in pigs, rectal overexposure induces mucosal damage (crypt depletion, macrophage infiltration, and fibrosis). In a pig model, repeated administrations of MSCs controlled systemic inflammation, reduced in situ both expression of inflammatory cytokines and macrophage recruitment, and augmented interleukin-10 expression in rectal mucosa. MSC injections limited radiation-induced fibrosis by reducing collagen deposition and expression of col1a2/col3a1 and transforming growth factor-β/connective tissue growth factor, and by modifying the matrix metalloproteinase/TIMP balance. In a pig model of proctitis, repeated injections of MSCs effectively reduced inflammation and fibrosis. This treatment represents a promising therapy for radiation-induced severe rectal damage.

Probiotic yeast inhibits VEGFR signaling and angiogenesis in intestinal inflammation

Background and Aims

Saccharomyces boulardii (Sb) can protect against intestinal injury and tumor formation, but how this probiotic yeast controls protective mucosal host responses is unclear. Angiogenesis is an integral process of inflammatory responses in inflammatory bowel diseases (IBD) and required for mucosal remodeling during restitution. The aim of this study was to determine whether Sb alters VEGFR (vascular endothelial growth factor receptor) signaling, a central regulator of angiogenesis.

Methods

HUVEC were used to examine the effects of Sb on signaling and on capillary tube formation (using the ECMatrix™ system). The effects of Sb on VEGF-mediated angiogenesis were examined in vivo using an adenovirus expressing VEGF-A(164) in the ears of adult nude mice (NuNu). The effects of Sb on blood vessel volume branching and density in DSS-induced colitis was quantified using VESsel GENeration (VESGEN) software.

Results

1) Sb treatment attenuated weight-loss (p<0.01) and histological damage (p<0.01) in DSS colitis. VESGEN analysis of angiogenesis showed significantly increased blood vessel density and volume in DSS-treated mice compared to control. Sb treatment significantly reduced the neo-vascularization associated with acute DSS colitis and accelerated mucosal recovery restoration of the lamina propria capillary network to a normal morphology. 2) Sb inhibited VEGF-induced angiogenesis in vivo in the mouse ear model. 3) Sb also significantly inhibited angiogenesis in vitro in the capillary tube assay in a dose-dependent manner (p<0.01). 4) In HUVEC, Sb reduced basal VEGFR-2 phosphorylation, VEGFR-2 phosphorylation in response to VEGF as well as activation of the downstream kinases PLCγ and Erk1/2.

Conclusions

Our findings indicate that the probiotic yeast S boulardii can modulate angiogenesis to limit intestinal inflammation and promote mucosal tissue repair by regulating VEGFR signaling.

The mRNA level of the transforming growth factor β1 gene, but not the amount of the gene product, can be considered as a potential prognostic parameter in inflammatory bowel diseases in children

PURPOSE

Transforming growth factor β1 (TGF-β1) plays a role in cell proliferation and differentiation, and it can modulate immune response. In this work, we asked whether levels of either TGF-β1 or mRNA of the corresponding gene in plasma or tissue can be useful in diagnosing and/or monitoring of the clinical course of inflammatory bowel diseases (IBD).

METHODS

The study group consisted of 104 pediatric patients with IBD: 36 with Crohn's disease (CD) and 68 with ulcerative colitis (UC); 42 children represented the control group. TGF-β1 levels in plasma and intestinal mucosa were estimated by ELISA and immunohistochemistry (IHC), respectively. Levels of TGF-β1 mRNA were determined by reverse transcription and real-time PCR.

RESULTS

In patients with IBD, and in subgroups with CD and UC, no significant differences in the TGF-β1 level in plasma and tissue were found relative to the control group. These variables were not dependent on the stage of the disease, its activity or severity of endoscopic and histopathological findings. TGF-β1 mRNA levels were significantly higher in tissue samples withdrawn during the relapse of the disease than in those taken during the remission or in the control group. However, no correlation between TGF-β1 plasma levels and TGF-β1 mRNA amount in the intestinal mucosa was observed.

CONCLUSIONS

The TGF-β1 mRNA level, but not the amount of the gene product, was significantly increased in the pathologically changed tissue during the relapse of IBD. We suggest that this parameter might be considered as a potential prognostic value when assessing IBD in children.

Macrophage-mediated lymphangiogenesis: the emerging role of macrophages as lymphatic endothelial progenitors

It is widely accepted that macrophages and other inflammatory cells support tumor progression and metastasis. During early stages of neoplastic development, tumor-infiltrating macrophages (TAMs) mount an immune response against transformed cells. Frequently, however, cancer cells escape the immune surveillance, an event that is accompanied by macrophage transition from an anti-tumor to a pro-tumorigenic type. The latter is characterized by high expression of factors that activate endothelial cells, suppress immune response, degrade extracellular matrix, and promote tumor growth. Cumulatively, these products of TAMs promote tumor expansion and growth of both blood and lymphatic vessels that facilitate metastatic spread. Breast cancers and other epithelial malignancies induce the formation of new lymphatic vessels (i.e., lymphangiogenesis) that leads to lymphatic and subsequently, to distant metastasis. Both experimental and clinical studies have shown that TAMs significantly promote tumor lymphangiogenesis through paracrine and cell autonomous modes. The paracrine effect consists of the expression of a variety of pro-lymphangiogenic factors that activate the preexisting lymphatic vessels. The evidence for cell-autonomous contribution is based on the observed tumor mobilization of macrophage-derived lymphatic endothelial cell progenitors (M-LECP) that integrate into lymphatic vessels prior to sprouting. This review will summarize the current knowledge of macrophage-dependent growth of new lymphatic vessels with specific emphasis on an emerging role of macrophages as lymphatic endothelial cell progenitors (M-LECP).

Key Features of the Intragraft Microenvironment that Determine Long-Term Survival Following Transplantation

In this review, we discuss how changes in the intragraft microenvironment serve to promote or sustain the development of chronic allograft rejection. We propose two key elements within the microenvironment that contribute to the rejection process. The first is endothelial cell proliferation and angiogenesis that serve to create abnormal microvascular blood flow patterns as well as local tissue hypoxia, and precedes endothelial-to-mesenchymal transition. The second is the overexpression of local cytokines and growth factors that serve to sustain inflammation and, in turn, function to promote a leukocyte-induced angiogenesis reaction. Central to both events is overexpression of vascular endothelial growth factor (VEGF), which is both pro-inflammatory and pro-angiogenic, and thus drives progression of the chronic rejection microenvironment. In our discussion, we focus on how inflammation results in angiogenesis and how leukocyte-induced angiogenesis is pathological. We also discuss how VEGF is a master control factor that fosters the development of the chronic rejection microenvironment. Overall, this review provides insight into the intragraft microenvironment as an important paradigm for future direction in the field.

The cutaneous vascular system in chronic skin inflammation

The blood and lymphatic vasculature have an important role in skin homeostasis. Angiogenesis and lymphangiogenesis-the growth of new vessels from existing ones-have received tremendous interest because of their role in promoting cancer spread. However, there is increasing evidence that both vessel types also have a major role in acute and chronic inflammatory disorders. Vessels change their phenotype during inflammation (vascular remodeling). In inflamed skin, vascular remodeling consists of a hyperpermeable, enlarged network of vessels with increased blood flow, and influx of inflammatory cells. During chronic inflammation, the activated endothelium expresses adhesion molecules, cytokines, and other molecules that lead to leukocyte rolling, attachment, and migration into the skin. Recent studies reveal that inhibition of blood vessel activation exerts potent anti-inflammatory properties. Thus, anti-angiogenic drugs might be used to treat inflammatory conditions. In particular, topical application of anti-angiogenic drugs might be ideally suited to circumvent the adverse effects of systemic therapy with angiogenesis inhibitors. Our recent results indicate that stimulation of lymphatic vessel growth and function unexpectedly represents a new approach for treating chronic inflammatory disorders.

Dietary fish oil and curcumin combine to modulate colonic cytokinetics and gene expression in dextran sodium sulphate-treated mice

Both fish oil (FO) and curcumin have potential as anti-tumour and anti-inflammatory agents. To further explore their combined effects on dextran sodium sulphate (DSS)-induced colitis, C57BL/6 mice were randomised to four diets (2 × 2 design) differing in fatty acid content with or without curcumin supplementation (FO, FO+2 % curcumin, maize oil (control, MO) or MO+2 % curcumin). Mice were exposed to one or two cycles of DSS in the drinking-water to induce either acute or chronic intestinal inflammation, respectively. FO-fed mice exposed to the single-cycle DSS treatment exhibited the highest mortality (40 %, seventeen of forty-three) compared with MO with the lowest mortality (3 %, one of twenty-nine) (P = 0·0008). Addition of curcumin to MO increased (P = 0·003) mortality to 37 % compared with the control. Consistent with animal survival data, following the one- or two-cycle DSS treatment, both dietary FO and curcumin promoted mucosal injury/ulceration compared with MO. In contrast, compared with other diets, combined FO and curcumin feeding enhanced the resolution of chronic inflammation and suppressed (P < 0·05) a key inflammatory mediator, NF-κB, in the colon mucosa. Mucosal microarray analysis revealed that dietary FO, curcumin and FO plus curcumin combination differentially modulated the expression of genes induced by DSS treatment. These results suggest that dietary lipids and curcumin interact to regulate mucosal homeostasis and the resolution of chronic inflammation in the colon.

Role of the endothelium in inflammatory bowel diseases

Inflammatory bowel diseases (IBD) are a complex group of diseases involving alterations in mucosal immunity and gastrointestinal physiology during both initiation and progressive phases of the disease. At the core of these alterations are endothelial cells, whose continual adjustments in structure and function coordinate vascular supply, immune cell emigration, and regulation of the tissue environment. Expansion of the endothelium in IBD (angiogenesis), mediated by inflammatory growth factors, cytokines and chemokines, is a hallmark of active gut disease and is closely related to disease severity. The endothelium in newly formed or inflamed vessels differs from that in normal vessels in the production of and response to inflammatory cytokines, growth factors, and adhesion molecules, altering coagulant capacity, barrier function and blood cell recruitment in injury. This review examines the roles of the endothelium in the initiation and propagation of IBD pathology and distinctive features of the intestinal endothelium contributing to these conditions.

Stimulation of lymphangiogenesis via VEGFR-3 inhibits chronic skin inflammation

The role of lymphangiogenesis in inflammation has remained unclear. To investigate the role of lymphatic versus blood vasculature in chronic skin inflammation, we inhibited vascular endothelial growth factor (VEGF) receptor (VEGFR) signaling by function-blocking antibodies in the established keratin 14 (K14)-VEGF-A transgenic (Tg) mouse model of chronic cutaneous inflammation. Although treatment with an anti-VEGFR-2 antibody inhibited skin inflammation, epidermal hyperplasia, inflammatory infiltration, and angiogenesis, systemic inhibition of VEGFR-3, surprisingly, increased inflammatory edema formation and inflammatory cell accumulation despite inhibition of lymphangiogenesis. Importantly, chronic Tg delivery of the lymphangiogenic factor VEGF-C to the skin of K14-VEGF-A mice completely inhibited development of chronic skin inflammation, epidermal hyperplasia and abnormal differentiation, and accumulation of CD8 T cells. Similar results were found after Tg delivery of mouse VEGF-D that only activates VEGFR-3 but not VEGFR-2. Moreover, intracutaneous injection of recombinant VEGF-C156S, which only activates VEGFR-3, significantly reduced inflammation. Although lymphatic drainage was inhibited in chronic skin inflammation, it was enhanced by Tg VEGF-C delivery. Together, these results reveal an unanticipated active role of lymphatic vessels in controlling chronic inflammation. Stimulation of functional lymphangiogenesis via VEGFR-3, in addition to antiangiogenic therapy, might therefore serve as a novel strategy to treat chronic inflammatory disorders of the skin and possibly also other organs.

Fibroblast growth factor-2 and vascular endothelial growth factor expression in the ileocecal region of quail (Coturnix coturnix japonica)

We undertook this study to immunolocalize in quail vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF-2) in the ileocecal region, which is a significant entry point for intestinal immunity. Diffuse cytoplasmic reaction for FGF-2 and VEGF was observed in the epithelial cells of the distal ileum and proximal cecal mucosa. VEGF immunoreactive cells, which give strong intracytoplasmic immunoreaction, were observed in the lamina propria of both intestinal parts. FGF-2 immunoreactive cells were seen in the lamina propria and germinative centers of lymph follicles in the cecum mucosa. Expressions of FGF-2 and VEGF in healthy quail intestines indicate that these factors have physiological roles in quail.

The angiogenic effect of probiotic Bacillus polyfermenticus on human intestinal microvascular endothelial cells is mediated by IL-8

Angiogenesis is required for wound healing and repair, but dysregulated angiogenesis is involved in gastrointestinal inflammation. Bacillus polyfermenticus (B.P.) is a probiotic bacterium clinically used for a variety of intestinal disorders in East Asia. Here we investigated the effect of B.P. on angiogenesis of human intestinal microvascular endothelial cells (HIMECs) and wound healing in intestinal mucosa. Exposure of HIMECs to the conditioned medium of B.P. cultures (B.P. CM) increased cell migration, permeability, and tube formation. Production of the proangiogenic cytokine IL-8 was increased by B.P. CM, and neutralizing antibodies against IL-8 or IL-8 receptor CXCR2 reduced tube formation as well as actin stress fiber formation. B.P. CM also increased NF-kappaB activation, and inhibitors of NF-kappaB suppressed B.P. CM-induced tube formation and IL-8 production. Furthermore, B.P. facilitated recovery of mice from colitis as shown by increased body weight and reduced rectal bleeding and histological severity. B.P. also increased angiogenesis and mouse IL-8 production in the mucosal layer. Collectively, these results show that B.P. increases angiogenesis of HIMECs in a NF-kappaB/IL-8/CXCR2-dependent manner. Moreover, B.P. promotes angiogenesis in the mucosa during recovery of mice from colitis, suggesting that this probiotic may be clinically used to facilitate intestinal wound healing.

CD40-induced signaling in human endothelial cells results in mTORC2- and Akt-dependent expression of vascular endothelial growth factor in vitro and in vivo

We have examined CD40-dependent signals in endothelial cells (EC) mediating the expression of vascular endothelial growth factor (VEGF) and VEGF-induced angiogenesis. We treated confluent cultures of EC with soluble CD40L (sCD40L), and by Western blot found a marked increase in the phosphorylation of Akt, 4EBP-1, and S6K1, compared with untreated cells. EC were transfected with a full-length VEGF promoter-luciferase construct and cultured in the absence or presence of rapamycin and sCD40L. We found that rapamycin, which blocks mTORC1 and mTORC2 signaling, inhibited sCD40L-mediated transactivation of VEGF. In addition, by Western blot, we found that the transfection of EC with small interfering RNA (siRNA) to rictor (to inhibit mTORC2), and not raptor (to inhibit mTORC1), inhibited sCD40L-dependent protein expression of VEGF. In additions, we found that basal levels of phosphorylated Akt as well as VEGF were increased in EC transfected with the raptor siRNA. Also, rapamycin failed to inhibit VEGF promoter activation, as well as VEGF protein expression in EC transfected with a constitutively active construct of Akt, further demonstrating that mTORC1 is not necessary for CD40- and Akt-induced expression of VEGF. Finally, we injected human CD40L-transfected fibroblasts or mock transfectants into human skin on SCID mice. We found that the injection of CD40L transfectants, but not mock cells, resulted in VEGF expression and mediated a marked angiogenesis reaction, and this response was reduced in mice treated with rapamycin. Together, these observations indicate that mTORC2 and Akt facilitate CD40-inducible expression of VEGF in EC, which is of clinical importance in tumor growth and the progression of chronic inflammatory diseases.

Immune-mediated signaling in intestinal goblet cells via PI3-kinase- and AKT-dependent pathways

In the intestinal epithelium, activation of phosphatidylinositol 3-kinase (PI3-kinase)/AKT pathways, via growth factor-mediated signaling, has been shown to regulate cell proliferation and inhibit apoptosis. An immune-activated receptor critical for Th2 immune responses, IL-4Ralpha can also activate PI3-kinase via insulin receptor substrate (IRS)-dependent signaling. Here, using the intestinal goblet cell-specific gene RELMbeta, we investigated the effect of PI3-kinase activation via Th2 immune responses on the goblet cell phenotype. IL-13 stimulation activated PI3-kinase and AKT signal transduction in LS174T cells. Not only did pharmacological inhibition of PI3-kinase and AKT1/2 inhibit RELMbeta induction by IL-13, but AKT inhibition also significantly reduced constitutive basal expression of RELMbeta, a response reproduced by the simultaneous pharmacological inhibition of both epidermal growth factor receptor and IGF-I receptor signaling. In vivo, the disruption of phosphatase and tensin homolog deleted on chromosome 10 (PTEN), an inhibitor of PI3-kinase activation, led to the activation of RELMbeta expression in the small intestine. Furthermore, induction of an intestinal Th2 immune response by infection with a small intestinal nematode parasite, Heligmosomoides polygyrus, led to enhanced epithelial cell proliferation, activation of AKT as demonstrated by the loss of Foxo1 nuclear localization, and robust induction of RELMbeta expression in wild-type, but not IL-4Ralpha knockout, mice. These results demonstrate that Th2 immune responses can regulate goblet cell responses by activation of PI3-kinase and AKT pathways via IL-4Ralpha.

Role of cytokines in inflammatory bowel disease

Inflammatory bowel disease (IBD), which includes Crohn’s disease (CD) and ulcerative colitis (UC), represents a group of chronic disorders characterized by inflammation of the gastrointestinal tract, typically with a relapsing and remitting clinical course. Mucosal macrophages play an important role in the mucosal immune system, and an increase in the number of newly recruited monocytes and activated macrophages has been noted in the inflamed gut of patients with IBD. Activated macrophages are thought to be major contributors to the production of inflammatory cytokines in the gut, and imbalance of cytokines is contributing to the pathogenesis of IBD. The intestinal inflammation in IBD is controlled by a complex interplay of innate and adaptive immune mechanisms. Cytokines play a key role in IBD that determine T cell differentiation of Th1, Th2, T regulatory and newly described Th17 cells. Cytokines levels in time and space orchestrate the development, recurrence and exacerbation of the inflammatory process in IBD. Therefore, several cytokine therapies have been developed and tested for the treatment of IBD patients.