Growth factors in inflammatory bowel disease: the actions and interactions of growth hormone and insulin-like growth factor-I

A Masking Effect: A Case of Initial Presentation of Ulcerative Colitis After Discontinuing Growth Hormone Therapy

Background

The inflammation and repair of the intestinal mucosa in inflammatory bowel disease (IBD) involve a complex interplay between innate, adaptive immune responses, and hormones. This may explain the relapsing clinical course of the disease.

Methods

We present the first reported case of a patient presenting their initial flare of ulcerative colitis immediately after discontinuing growth hormone (GH) therapy, suggesting treatment with GH or growth factors may prevent the development of IBD.

Results

This is a case of a 13-year-old female with a history of GH deficiency, presenting with an 8-week history of abdominal pain, blood-stained diarrhea, and fecal calprotectin greater than 8000 mcg/g, 2 weeks after discontinuing GH therapy. The patient subsequently underwent an esophagoduodenoscopy and colonoscopy with biopsies showing histological features consistent with ulcerative colitis.

Conclusions

The finding of withdrawing GH or growth factors therapy potentially unmasking IBD in this patient raises a question of whether growth factors can inhibit the development of IBD and suggests beneficial effects of treatment with GH or growth factors as adjuvant therapy for IBD.

Macrophages-microenvironment crosstalk in fibrostenotic inflammatory bowel disease: from basic mechanisms to clinical applications

INTRODUCTION

Intestinal fibrosis is a common complication of Inflammatory Bowel Disease (IBD) with no available drugs. The current therapeutic principle is surgical intervention as the core. Intestinal macrophages contribute to both the progression of inflammation and fibrosis. Understanding the role of macrophages in the intestinal microenvironment could bring new hope for fibrosis prevention or even reversal.

AREAS COVERED

This article reviewed the most relevant reports on macrophage in the field of intestinal fibrosis. The authors discussed current opinions about how intestinal macrophages function and interact with surrounding mediators during inflammation resolution and fibrostenotic IBD. Based on biological mechanisms findings, authors summarized related clinical trial outcomes.

EXPERT OPINION

The plasticity of intestinal macrophages allows them to undergo dramatic alterations in their phenotypes or functions when exposed to gastrointestinal environmental stimuli. They exhibit distinct metabolic characteristics, secrete various cytokines, express unique surface markers, and transmit different signals. Nevertheless, the specific mechanism through which the intestinal macrophages contribute to intestinal fibrosis remains unclear. It should further elucidate a novel therapeutic approach by targeting macrophages, especially distinct mechanisms in specific subgroups of macrophages involved in the progression of fibrogenesis in IBD.

Greater Adherence to Cardioprotective Diet Can Reduce Inflammatory Bowel Disease Risk: A Longitudinal Cohort Study

Background: The cardioprotective diet was reported to be associated with several chronic cardiometabolic diseases through an anti-inflammation effect. However, the association between the cardioprotective diet and the risk of inflammatory bowel disease (IBD) was unclear and deserved to be further explored. Methods: We calculated the cardioprotective diet score based on the consumptions of seven common food groups using the validated food frequency questionnaire data in the UK Biobank. Incident IBD was ascertained from primary care data, inpatient data, and the death registry. Cox proportional hazard models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between the cardioprotective diet score and the risk of IBD. Results: During a mean follow-up of 12.1 years, we documented 2717 incident IBD cases, including 851 cases of Crohn’s disease and 1866 cases of ulcerative colitis. Compared to participants with a cardioprotective diet score of 0−1, we observed a decreased risk of IBD among participants with cardioprotective diet scores of 3 (HR 0.85, 95% CI 0.73−0.99), 4 (HR 0.84, 95% CI 0.72−0.98), and 5−7 (HR 0.77, 95% CI 0.66−0.89) (p-trend < 0.001). Conclusions: A greater adherence to the cardioprotective diet was associated with a lower risk of IBD. Our finding highlighted the importance of focusing on the cardioprotective diet to prevent IBD.

New-Onset of Inflammatory Bowel Disease in a Patient Treated With Teprotumumab for Thyroid Associated Ophthalmopathy

A patient with thyroid-associated ophthalmopathy was treated with teprotumumab and developed symptoms concerning for inflammatory bowel disease after her sixth infusion. Colonoscopy was performed, and mucosal biopsies identified evidence of active colitis consistent with a diagnosis of ulcerative colitis. Despite treatment with budesonide and mesalamine, the patient continued to be symptomatic one and a half months after cessation of teprotumumab and required infliximab to achieve good control of her inflammatory bowel disease. This case represents the first report of new-onset inflammatory bowel disease arising during treatment with teprotumumab.

Teprotumumab: Interpreting the Clinical Trials in the Context of Thyroid Eye Disease Pathogenesis and Current Therapies

Teprotumumab, a monoclonal antibody targeted against the insulin-like growth factor 1 (IGF-1) receptor, was recently approved by the United States Food and Drug Administration for the treatment of thyroid eye disease (TED). Phase 1 studies of teprotumumab for the treatment of malignancies demonstrated an acceptable safety profile but limited effectiveness. Basic research implicating the IGF-1 receptor on the CD-34+ orbital fibrocyte in the pathogenesis of TED renewed interest in the drug. Two multicenter, randomized, double-masked, clinical trials (phase 2 and 3) evaluated the efficacy of 8 infusions of teprotumumab every 3 weeks versus placebo in 170 patients with recent-onset active TED, as defined by a clinical activity score (CAS) of at least 4. Teprotumumab was superior to placebo for the primary efficacy end points in both studies: overall responder rate as defined by a reduction of 2 or more CAS points and a reduction of 2 mm or more in proptosis (69% vs. 20%; P < 0.001; phase 2 study) and proptosis responder rate as defined by a reduction of 2 mm or more in proptosis (83% vs. 10%; P < 0.001; phase 3 study). In both studies, treatment with teprotumumab compared with placebo achieved a significant mean reduction of proptosis (-3.0 mm vs. -0.3 mm, phase 2 study; -3.32 mm vs. -0.53 mm, phase 3 study) and CAS (-4.0 vs. -2.5, phase 2 study; -3.7 vs. -2.0, phase 3 study). Teprotumumab also resulted in a greater proportion of patients with a final CAS of 0 or 1, higher diplopia responder rate, and a larger improvement in the Graves' Ophthalmopathy Quality of Life overall score. More than half of patients (62%, phase 2 trial; 56%, phase 3 trial) who were primary end point responders maintained this response at 51 weeks after the last dose of therapy. The most common adverse events reported with teprotumumab included muscle spasms (25%), nausea (17%), alopecia (13%), diarrhea (13%), fatigue (10%), hearing impairment (10%), and hyperglycemia (8%). Teprotumumab is contraindicated for those with inflammatory bowel disease and who are pregnant. Although the current dosing regimen has proven effective for TED, dose-ranging studies including variable concentrations, infusion frequencies, and durations of teprotumumab therapy in the setting of TED have not been performed.

A case of ulcerative colitis associated with teprotumumab treatment for thyroid eye disease

Purpose

To present a case of ulcerative colitis associated with teprotumumab treatment for thyroid eye disease.

Observations

A 46-year-old Indian female was treated with teprotumumab (Tepezza) for severe thyroid eye disease within 9 months of diagnosis. The patient noted progression of her disease on oral prednisone and demonstrated severe, debilitating proptosis accompanied by eye ache and dry eyes. After 5 infusions of teprotumumab over a four-month period, the patient developed bloody diarrhea and fecal urgency. These symptoms progressively worsened and after two additional treatments, she underwent a colonoscopy. This confirmed the diagnosis of ulcerative colitis (UC). Treatment with teprotumumab was halted prior to the administration of the 8th infusion; however, the patient continued to have severe gastrointestinal symptoms two months after her last treatment.

Conclusions and importance

Teprotumumab is an insulin-like growth factor-1 receptor (IGF-1R) inhibitor demonstrated to improve proptosis in patients with active thyroid eye disease. Most adverse events reported are mild or moderate in severity; however, inflammatory bowel disease (IBD) is a serious adverse event that can develop as a result of treatment.

Oleanolic acid ameliorates intestinal alterations associated with EAE

Background

Multiple sclerosis (MS) is a chronic demyelinating autoimmune disease affecting the CNS. Recent studies have indicated that intestinal alterations play key pathogenic roles in the development of autoimmune diseases, including MS. The triterpene oleanolic acid (OA), due to its anti-inflammatory properties, has shown to beneficially influence the severity of the experimental autoimmune encephalomyelitis (EAE), a preclinical model of MS. We herein investigate EAE-associated gut intestinal dysfunction and the effect of OA treatment.

Methods

Mice with MOG_35–55-induced EAE were treated with OA or vehicle from immunization day and were daily analyzed for clinical deficit. We performed molecular and histological analysis in serum and intestinal tissues to measure oxidative and inflammatory responses. We used Caco-2 and HT29-MTX-E12 cells to elucidate OA in vitro effects.

Results

We found that OA protected from EAE-induced changes in intestinal permeability and preserved the mucin-containing goblet cells along the intestinal tract.

Serum levels of the markers for intestinal barrier damage iFABP and monocyte activation sCD14 were consistently and significantly reduced in OA-treated EAE mice. Beneficial OA effects also included a decrease of pro-inflammatory mediators both in serum and colonic tissue of treated-EAE mice. Moreover, the levels of some immunoregulatory cytokines, the neurotrophic factor GDNF, and the gastrointestinal hormone motilin were preserved in OA-treated EAE mice. Regarding oxidative stress, OA treatment prevented lipid peroxidation and superoxide anion accumulation in intestinal tissue, while inducing the expression of the ROS scavenger Sestrin-3. Furthermore, short-chain fatty acids (SCFA) quantification in the cecal content showed that OA reduced the high iso-valeric acid concentrations detected in EAE-mice. Lastly, using in vitro cell models which mimic the intestinal epithelium, we verified that OA protected against intestinal barrier dysfunction induced by injurious agents produced in both EAE and MS.

Conclusion

These findings reveal that OA ameliorates the gut dysfunction found in EAE mice. OA normalizes the levels of gut mucosal dysfunction markers, as well as the pro- and anti-inflammatory immune bias during EAE, thus reinforcing the idea that OA is a beneficial compound for treating EAE and suggesting that OA may be an interesting candidate to be explored for the treatment of human MS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-020-02042-6.

Elevated serum insulin-like growth factor 1 in recurrent aphthous stomatitis

Over 100 million Americans experience recurrent aphthous stomatitis (RAS) at some point in life. To develop targeted drugs for RAS treatment, it is critical to identify its etiology. We determined if serum insulin‐like growth factor 1 (IGF‐1) and related factors are associated with RAS, because both RAS prevalence and IGF‐1 are highest during puberty. We analyzed data from 1,480 Third National Health and Nutrition Examination Survey participants aged 20–40 years. Participants with a history of diabetes or lupus, cotinine levels 6 ng/ml or higher or glycemia 110 mg/dl or higher were excluded. We compared levels of IGF‐1, IGFBP‐3, leptin, and insulin in participants with a positive vs. negative RAS history in the prior 12 months. We used logistic regression in SAS/SUDAAN to account for the complex sampling design. The odds of a positive RAS history were 1.31 times higher for every 100 ng/ml increase in serum IGF‐1. This association persisted after adjustment for age, race/ethnicity, medication intake, body mass index, insulin, leptin, glycemia, and income (adjusted OR = 1.30, 95% CI [1.06, 1.60]; p = 0.013). The odds of a positive RAS history were also higher among non‐Hispanic white compared with non‐Hispanic black participants (adjusted OR = 4.37, 95% CI [3.00, 6.38]). Leptin, IGFBP‐3, and insulin levels did not differ by RAS status. The significantly higher IGF‐1 levels in participants with a positive RAS history compared with controls suggest a possible role of the IGF‐1 pathway in RAS etiology.

The pre-treatment characteristics and evaluation of the effects of recombinant human growth hormone therapy in children with growth hormone deficiency and celiac disease or inflammatory bowel disease

The aim of the study

was to investigate the coincidence of growth hormone deficiency (GHD) and celiac disease (CD) or inflammatory bowel disease (IBD) in patients referred for short stature, and to evaluate the baseline anthropometric parameters and the effectiveness of recombinant human growth hormone (rhGH) therapy in the first year in those patients (GHD+CD/IBD subgroup) in comparison to patients with GHD without CD or IBD (GHD-CD/IBD subgroup).

Material and methods

The study was retrospective and included 2196 short patients (height SDS [Standard Deviation Score] ≤ –1.2). 1454 patients had height SDS ≤ –2. Twenty-nine patients suffered from CD or IBD. GHD was confirmed in 419 patients with height SDS ≤ –2. The coexistence of GHD and CD or IBD was found in seven patients (GHD+CD/IBD subgroup).

Results

At baseline the GHD-CD/IBD subgroup did not differ significantly in chronological age, height SDS, height velocity (HV) before rhGH therapy, body weight SDS, and body mass index SDS from the GHD+CD/IBD subgroup. The improvement in height SDS within the first year of rhGH therapy was higher in the GHD+CD/IBD subgroup than in the GHD-CD/IBD subgroup and the difference was statistically significant (p<0.05). HV in the first year of rhGH therapy was also significantly higher in the GHD+CD/IBD subgroup than in the GHD-CD/IBD subgroup (p < 0.05).

Conclusions

In patients with chronic inflammatory disorders of the gastrointestinal tract, especially celiac disease, coexisting with GHD, rhGH therapy could be effective and should be administered together with therapy of primary gastrointestinal disease.

Benzoic acid beneficially affects growth performance of weaned pigs which was associated with changes in gut bacterial populations, morphology indices and growth factor gene expression

This study was conducted to investigate the effects of benzoic acid (BA) on growth performance, intestinal development and intestinal barrier function in weaned pigs. Ninety weaned pigs were randomly assigned to one of three treatments: a basal diet (CON), the basal diet supplemented with 2000 mg/kg benzoic acid (BA1) and 5000 mg/kg benzoic acid (BA2). At the end of days 14 and 42, six pigs per treatment were randomly selected to collect plasma and intestinal samples. Results showed that BA supplementation not only improved final body weight, daily growth and feed conversion ratio from days 15 to 42 and days 1 to 42, but also decreased the activity of plasma diamine oxidase (day 42) and the pH values of jejunal contents (day 14) (p < 0.05). Ileal Bacillus populations (day 14) were increased by BA, while Escherichia coli counts in the ileum and caecum (day 42) were decreased (p < 0.05). Higher Lactobacillus counts occurred in the ileum (day 14, 42) of BA1-fed piglets as compared to CON and BA2-fed piglets (p < 0.05). In addition, BA supplementation increased the ratio of villus height to crypt depth (day 14, 42) and decreased the crypt depth (day 14) (p < 0.05). Growth-stimulating factors (insulin-like growth factor-1, day 42; insulin-like growth factor-1 receptor, day 14, 42) and tight junction protein (occludin, day 14, 42; zonula occludens-1, day 42)-related gene mRNA levels were upregulated in the jejunum of piglets fed BA diets (p < 0.05). In conclusion, this study provides the first evidence that BA has beneficial effects on intestinal development and intestinal barrier function of weaned pigs, which can partly explain why growth performance of pigs was improved by dietary BA supplementation.

Anti-TNFα alters the natural history of experimental Crohn's disease in rats when begun early, but not late, in disease

Anti-TNFα therapy decreases inflammation in Crohn's disease (CD). However, its ability to decrease fibrosis and alter the natural history of CD is not established. Anti-TNF-α prevents inflammation and fibrosis in the peptidoglycan-polysaccharide (PG-PS) model of CD. Here we studied anti-TNF-α in a treatment paradigm. PG-PS or human serum albumin (HSA; control) was injected into bowel wall of anesthetized Lewis rats at laparotomy. Mouse anti-mouse TNF-α or vehicle treatment was begun day (d)1, d7, or d14 postlaparotomy. Rats were euthanized d21-23. Gross abdominal and histologic findings were scored. Cecal levels of relevant mRNAs were measured by quantitative real-time PCR. There was a stepwise loss of responsiveness when anti-TNFα was begun on d7 and d14 compared with d1 that was seen in the percent decrease in the median gross abdominal score and histologic inflammation score in PG-PS-injected rats [as %decrease; gross abdominal score: d1 = 75% (P = 0.003), d7 = 57% (P = 0.18), d14 = no change (P = 0.99); histologic inflammation: d1 = 57% (P = 0.006), d7 = 50% (P = 0.019), d14 = no change (P = 0.99)]. This was also reflected in changes in IL-1β, IL-6, TNF-α, IGF-I, TGF-β1, procollagen I, and procollagen III mRNAs that were decreased or trended downward in PG-PS-injected animals given anti-TNF-α beginning d1 or d7 compared with vehicle-treated rats; there was no effect if anti-TNF-α was begun d14. This change in responsiveness to anti-TNFα therapy was coincident with a major shift in the cytokine milieu observed on d14 in the PG-PS injected rats (vehicle treated). Our data are consistent with the clinical observation that improved outcomes occur when anti-TNF-α therapy is initiated early in the course of CD.

Insulin-Like Growth Factor-1 Contributes to Mucosal Repair by β-Arrestin2-Mediated Extracellular Signal-Related Kinase Signaling in Experimental Colitis

Insulin-like growth factor-1 (IGF-1) possesses the ability to attenuate intestinal damage and promote mucosal repair of colitis. β-Arrestins, as the scaffolding proteins of G protein-coupled receptors or non-G protein-coupled receptors signaling, can be involved in IGF-1-mediated signaling pathways. However, the interaction of IGF-1 and β-arrestin2 in the mucosal repair of experimental colitis remains unexplored. Ulcerative colitis was induced in β-arrestin2 wild-type mice and β-arrestin2 knockout littermates by using 3% dextran sulfate sodium for 5 days, followed by regular water consumption for 1, 2, 3, and 4 weeks to analyze the mucosal repair from experimental colitis. Disease activity index and histologic score analyses were performed. Apoptosis and proliferation were assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling and Ki-67 staining, respectively. The expressions of β-arrestin2, phospho (p)-IGF-1R, and p-extracellular signal-regulated kinase (ERK)1/2 were examined. Furthermore, β-arrestin2 was overexpressed or altered in HCT116 cells by transfection before IGF-1 treatment in vitro. IGF-1 and β-arrestin2 expression was up-regulated in the repairing phase of experimental colitis. Targeted deletion of β-arrestin2 delayed the repair of colitis by inhibiting cell proliferation without affecting the levels of IGF-1 and p-IGF-1R. The β-arrestin2/ERK signaling pathway was involved in IGF-1-mediated mucosal repair through promoting epithelial cell and goblet cell regeneration from experimental colitis. These results indicate that IGF-1 contributes to the mucosal repair by β-arrestin2-mediated ERK signaling in experimental colitis.

Is insulin-like growth factor 1 (IGF-1) system an attractive target inflammatory bowel diseases? Benefits and limitation of potential therapy

Inflammatory bowel diseases (IBD) are chronic gastrointestinal disorders with unknown etiology, whose incidence dramatically increased over the past 50 years. Currently available strategies for IBD treatment, such as biological therapies, corticosteroids, and immunosuppressive agents are effective, but their side effects and economic costs cannot be ignored. Better understanding of IBD etiology and new therapeutics are thus needed. The aim of this paper is to briefly discuss IGF-1 dependent functions, with particular focus on IGF-1 use in IBD therapy. Data collection was based on records found in medical literature. Data analysis included records published between 1984 and 2014. The IGF-1 system is involved in major physiological functions, such as cell proliferation and metabolism, and growth promotion. Most importantly IGF-1 has anti-inflammatory properties and its use in IBD treatment can be recommended. However, potential IGF-1 therapy has some limitations, which include aggravation of fibrosis in Crohn's patients and facilitated transformation to malignancy. Taken into consideration their possible side effects, IGF-1 analogs and recombinants are nonetheless a promising target for IBD therapy for a specific group of patients. Further studies, at the clinical level are thus recommended.

Insulin-like growth factor-1 endues monocytes with immune suppressive ability to inhibit inflammation in the intestine

The pathogenesis of some chronic inflammation such as inflammatory bowel disease is unclear. Insulin-like growth factor-1 (IGF1) has active immune regulatory capability. This study aims to investigate into the mechanism by which IGF1 modulates the monocyte (Mo) properties to inhibit immune inflammation in the intestine. In this study, the production of IGF1 by intestinal epithelial cells was evaluated by real time RT-PCR and Western blotting. Mos were analyzed by flow cytometry. A mouse colitis model was created with trinitrobenzene sulfonic acid. The results showed that mouse IECs produced IGF1, which could be up regulated by exposure to CpG-ODN (CpG-oligodeoxynueleotides) in the culture. Culture the CpG-ODN-primed IEC cells and Mos or exposure of Mos to IGF1 in the culture induced the Mos to express IL-10. The IGF1-primed Mos showed the immune suppressive effect on inhibiting the immune inflammation in the mouse colon. In conclusion, the IGF1-primed Mos are capable of suppressing immune inflammation in the intestine.

Sleep quality, BDNF genotype and gene expression in individuals with chronic abdominal pain

BACKGROUND

Sleep quality and genetics may contribute to the etiology of gastrointestinal (GI) symptoms. Individuals with impaired sleep often have a number of associated symptoms including chronic abdominal pain (CAP). The current study examined the interactions of brain-derived neurotrophic factor (BDNF) genotype with sleep quality in persons with CAP and healthy controls. In addition, associations among sleep quality, BDNF genotype, and gene expression were explored in the participants.

METHODS

Data were collected on 59 participants (46% male, 61% White, 26.9 ± 6.6 years; CAP (n=19) and healthy controls (n=40)). Participants with CAP reported poorer sleep quality compared to healthy controls. BDNF genotype, categorized as Val/Val homozygotes versus the Met carriers.

RESULTS

Microarray analysis found twenty-four differentially expressed genes by a two-fold magnitude in participants with poor sleep quality compared to good sleep quality, and seven differentially expressed genes comparing CAP to healthy control. Three specific genes in the pain group overlap with sleep quality, including insulin-like growth factor 1 (IGF1), spermatogenesis associated serine-rich 2-like (SPATS2L), and immunoglobulin heavy constant gamma 1 or mu (IGHG1/// IGHM). BDNF was shown to have an interaction effect with GI and sleep symptoms.

CONCLUSIONS

Participants with CAP reported poor sleep quality compared to healthy controls. The role of the BDNF Met allele on differential gene expression was not distinct as main factor, but impacted interactions with sleep quality and CAP. Down-regulation of IGF1, SPATS2L, and IGHG1 expression may be related to the etiology of poor sleep quality and CAP.

TRIAL REGISTRATION

Clinicaltrial.gov # NCT00824941.

Neurotrophin signaling and visceral hypersensitivity

Neurotrophin family are traditionally recognized for their nerve growth promoting function and are recently identified as crucial factors in regulating neuronal activity in the central and peripheral nervous systems. The family members including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) are reported to have distinct roles in the development and maintenance of sensory phenotypes in normal states and in the modulation of sensory activity in disease. This paper highlights receptor tyrosine kinase (Trk) -mediated signal transduction by which neurotrophins regulate neuronal activity in the visceral sensory reflex pathways with emphasis on the distinct roles of NGF and BDNF signaling in physiologic and pathophysiological processes. Viscero-visceral cross-organ sensitization exists widely in human diseases. The role of neurotrophins in mediating neural cross talk and interaction in primary afferent neurons in the dorsal root ganglia (DRG) and neurotrophin signal transduction in the context of cross-organ sensitization are also discussed.

Potential role of IGF-1 z score to predict permanent linear growth impairment in children with IBD

In this pilot study, we analyzed serum insulin-like growth factor 1 (IGF-1)- and IGF-binding protein-3-for-age z scores from 54 inflammatory bowel disease children with no, temporary, or permanent growth impairment. Although our findings did not reach statistical significance, patients with permanent linear growth impairment had lower IGF-1-for-age z scores (-1.76 [-2.25 to -0.43]) compared with those with no or temporary growth impairment (-0.84 [-1.49 to -0.3]) and -1.16 [-1.59 to -1.51], respectively). IGF-binding protein-3 levels were similar across the 3 groups. In the absence of significant inflammation and malnutrition, lower IGF-1-for-age z scores may help distinguish patients likely to have permanent growth impairment from those whose growth impairment is likely to be temporary.

In vivo regulation of brain-derived neurotrophic factor in dorsal root ganglia is mediated by nerve growth factor-triggered Akt activation during cystitis

The role of brain-derived neurotrophic factor (BDNF) in sensory hypersensitivity has been suggested; however the molecular mechanisms and signal transduction that regulate BDNF expression in primary afferent neurons during visceral inflammation are not clear. Here we used a rat model of cystitis and found that the mRNA and protein levels of BDNF were increased in the L6 dorsal root ganglia (DRG) in response to bladder inflammation. BDNF up-regulation in the L6 DRG was triggered by endogenous nerve growth factor (NGF) because neutralization of NGF with a specific NGF antibody reduced BDNF levels during cystitis. The neutralizing NGF antibody also subsequently reduced cystitis-induced up-regulation of the serine/threonine kinase Akt activity in L6 DRG. To examine whether the NGF-induced Akt activation led to BDNF up-regulation in DRG in cystitis, we found that in cystitis the phospho-Akt immunoreactivity was co-localized with BDNF in L6 DRG, and prevention of the endogenous Akt activity in the L6 DRG by inhibition of phosphoinositide 3-kinase (PI3K) with a potent inhibitor LY294002 reversed cystitis-induced BDNF up-regulation. Further study showed that application of NGF to the nerve terminals of the ganglion-nerve two-compartmented preparation enhanced BDNF expression in the DRG neuronal soma; which was reduced by pre-treatment of the ganglia with the PI3K inhibitor LY294002 and wortmannin. These in vivo and in vitro experiments indicated that NGF played an important role in the activation of Akt and subsequent up-regulation of BDNF in the sensory neurons in visceral inflammation such as cystitis.

The role of growth factors in intestinal regeneration and repair in necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a devastating intestinal disease resulting in major neonatal morbidity and mortality. The pathology is poorly understood, and the means of preventing and treating NEC are limited. Several endogenous growth factors have been identified as having important roles in intestinal growth as well as aiding intestinal repair from injury or inflammation. In this review, we will discuss several growth factors as mediators of intestinal regeneration and repair as well as potential therapeutic agents for NEC.

Tissue remodeling in eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a recently recognized, immune-mediated disease characterized clinically by symptoms of esophageal dysfunction and histologically by eosinophil-predominant inflammation. The chronic esophageal eosinophilia of EoE is associated with tissue remodeling that includes epithelial hyperplasia, subepithelial fibrosis, and hypertrophy of esophageal smooth muscle. This remodeling causes the esophageal rings and strictures that frequently complicate EoE and underlies the mucosal fragility that predisposes to painful mucosal tears in the EoE esophagus. The pathogenesis of tissue remodeling in EoE is not completely understood, but emerging studies suggest that secretory products of eosinophils and mast cells, as well as cytokines produced by other inflammatory cells, epithelial cells, and stromal cells in the esophagus, all contribute to the process. Interleukin (IL)-4 and IL-13, Th2 cytokines overproduced in allergic disorders, have direct profibrotic and remodeling effects in EoE. The EoE esophagus exhibits increased expression of transforming growth factor (TGF)-β1, which is a potent activator of fibroblasts and a strong inducer of epithelial-mesenchymal transition. In addition, IL-4, IL-13, and TGF-β all have a role in regulating periostin, an extracellular matrix protein that might influence remodeling by acting as a ligand for integrins, by its effects on eosinophils or by activating fibrogenic genes in the esophagus. Presently, few treatments have been shown to affect the tissue remodeling that causes EoE complications. This report reviews the potential roles of fibroblasts, eosinophils, mast cells, and profibrotic cytokines in esophageal remodeling in EoE and identifies potential targets for future therapies that might prevent EoE complications.

Dietary vegetable oils do not alter the intestine transcriptome of gilthead sea bream (Sparus aurata), but modulate the transcriptomic response to infection with Enteromyxum leei

Background

Studies conducted with gilthead sea bream (Sparus aurata L.) have determined the maximum dietary replacement of fish meal and oil without compromising growth or product quality. The present study aimed to analyze the effect of the nutritional background on fish health and fish fed plant protein-based diets with fish oil (FO diet) or a blend of vegetable oils (66VO diet) were exposed for 102 days to the intestinal myxosporean parasite Enteromyxum leei, and the intestine transcriptome was analyzed with a customized oligo-microarray of 7,500 annotated genes.

Results

Infection prevalence was high and similar in the two diet groups, but the outcome of the disease was more pronounced in fish fed the 66VO diet. No differences were found in the transcriptome of both diet control groups, whereas the number of differentially expressed genes in infected groups was considerable. K-means clustering of these differentially expressed genes identified four expression patterns that reflected the progression of the disease with the magnitude of the fold-change being higher in infected 66VO fish. A positive correlation was found between the time of infection and the magnitude of the transcriptional change within the 66VO group, being higher in early infected animals. Within this diet group, a strong up-regulation of many components of the immune specific response was evidenced, whereas other genes related to complement response and xenobiotic metabolism were down-regulated.

Conclusions

The high replacement of fish oil by vegetable oils in practical fish feeds did not modify the intestine transcriptome of gilthead sea bream, but important changes were apparent when fish were exposed to the myxosporean E. leei. The detected changes were mostly a consequence rather than a cause of the different disease progression in the two diet groups. Hence, the developed microarray constitutes an excellent diagnostic tool to address changes associated with the action of intestinal pathogens, but lacks a prognostic value to predict in advance the different susceptibility of growing fish to the current pathogen.

Insulin-like growth factors in the gastrointestinal tract and liver

The liver is a major source of insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs) that are present in the circulation and have important endocrine activities relating to energy metabolism, body size, carcinogenesis, and various organ-specific functions. Although IGFs have only minor effects on the normal liver itself, production of IGFs and IGFBPs in a tissue-specific manner in the gastrointestinal tract exert important regulatory effects on cellular proliferation, survival, and apoptosis. IGFs and IGFBPs play important regulatory roles in the response of both the liver and the gastrointestinal tract to inflammation and in the development of neoplasia.

Insulin-like growth factor 1: common mediator of multiple enterotrophic hormones and growth factors

PURPOSE OF REVIEW

To summarize the recent evidence that insulin-like growth factor 1 (IGF1) mediates growth effects of multiple trophic factors and discuss clinical relevance.

RECENT FINDINGS

Recent reviews and original reports indicate benefits of growth hormone (GH) and long-acting glucagon-like peptide 2 (GLP2) analogs in short bowel syndrome and Crohn's disease. This review highlights the evidence that biomarkers of sustained small intestinal growth or mucosal healing and evaluation of intestinal epithelial stem cell biomarkers may improve clinical measures of intestinal growth or response to trophic hormones. Compelling evidence that IGF1 mediates growth effects of GH and GLP2 on intestine or linear growth in preclinical models of resection or Crohn's disease is presented, along with a concept that these hormones or IGF1 may enhance sustained growth if given early after bowel resection. Evidence that suppressor of cytokine signaling protein induction by GH or GLP2 in normal or inflamed intestine may limit IGF1-induced growth, but protect against risk of dysplasia or fibrosis, is reviewed. Whether IGF1 receptor mediates IGF1 action and potential roles of insulin receptors are addressed.

SUMMARY

IGF1 has a central role in mediating trophic hormone action in small intestine. Better understanding of benefits and risks of IGF1, receptors that mediate IGF1 action, and factors that limit undesirable growth are needed.

Intestinal growth factors: potential use in the treatment of inflammatory bowel disease and their role in mucosal healing

BACKGROUND

A key feature of inflammatory bowel disease (IBD) is impaired epithelial repair. Human growth factors comprise an array of signaling molecules that lead to ligand-specific signal transduction. Their downstream effects are associated with several cellular functions including epithelial healing in response to injury. Several studies have described specific growth factor deficiencies in patients with IBD, implicating their role in disease pathophysiology. The aim of this review was to describe currently known enterocyte-targeted growth factors, their mechanisms of action, and their potential therapeutic utility.

METHODS

The National Library of Medicine (http://www.pubmed.gov) and meeting abstracts were searched using the following terms: growth factor, intestine, colon, inflammatory bowel disease, Crohn's disease, ulcerative colitis, colitis, animal model, transforming growth factor, bone morphogenetic protein, activins, growth hormone, fibroblast growth factor, epidermal growth factor (EGF), keratinocyte growth factor (KGF), glucagon-like peptide II, granulocyte macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF), vascular endothelial growth factor (VEGF) inhibitors, and trefoil factors.

RESULTS

Several growth factors are therapeutic candidates in IBD. Growth hormone, KGF, EGF, teduglutide, GM-CSF/G-CSF have entered early clinical trials, whereas others are currently in preclinical evaluation.

CONCLUSIONS

There are several growth factors responsible for epithelial repair. Preliminary studies using recombinant growth factors seem promising in IBD preclinical and clinical trials.

Skeletal muscle catabolism in trinitrobenzene sulfonic acid-induced murine colitis

The present study determined whether the muscle atrophy produced by colitis is associated with altered rates of muscle protein synthesis or degradation, as well as the potential role of the local (eg, muscle) insulin-like growth factor (IGF) system and muscle-specific ubiquitin E3 ligases atrogin-1 and MuRF1 in mediating altered muscle protein balance. Colitis was induced in C57BL/6 mice by intrarectal administration of trinitrobenzene sulfonic acid (TNBS), and blood and tissues were collected on day 10. Mice with inflammatory bowel disease demonstrated reduced skeletal muscle mass and protein content, whereas colonic segment weight and gross damage score were both increased in mice with colitis, compared with time-matched control values. There was no change in muscle protein synthesis in mice with inflammatory bowel disease; but there was an increased protein breakdown (45%), proteasome activity (85%), and messenger RNA (mRNA) expression for atrogin-1 and MuRF1 (200%-300%) in muscle. These changes were associated with a reduction in liver (but not muscle) IGF-I mRNA as well as a reduction in both total and free IGF-I in the blood. Colitis decreased the hepatic content of IGF binding protein (IGFBP)-3 mRNA by 40% and increased IGFBP-1 mRNA by 100%. In contrast, colitis did alter IGFBP mRNAs in muscle. The tumor necrosis factor-α, interleukin-6, and nitric oxide synthase 2 mRNA content of both liver and skeletal muscle was increased in TNBS-treated mice; and plasma tumor necrosis factor-α and interleukin-6 concentrations were also elevated. These data suggest that TNBS-induced colitis is independent of a change in muscle protein synthesis but dependent on stimulation of protein degradation via increased expression of muscle-specific atrogenes, which may be mediated in part by the reduction in circulating concentration of IGF-I and the concomitant increase in inflammatory mediators observed in the blood and muscle per se.

A population-based study of IGF axis polymorphisms and the esophageal inflammation, metaplasia, adenocarcinoma sequence

BACKGROUND & AIMS

Insulin-like growth factor (IGF) axis plays a key role in cell development, proliferation, and survival and is implicated in the etiology of several cancers. Few studies have examined the relationship between genetic variation of this axis and esophageal adenocarcinoma (EAC) or its precursors.

METHODS

In a population-based case-control study, we investigated the association of common polymorphisms of IGF-1, IGF-2, IGF-1 receptor, IGF binding protein-3, growth hormones (GH) 1 and GH2, and GH receptor with reflux esophagitis (RE), Barrett esophagus (BE), and EAC. Two hundred and thirty RE, 224 BE, 227 EAC cases, and 260 controls were studied. Gene polymorphisms were identified using publicly available online resources; 102 IGF axis tag and putatively functional single-nucleotide polymorphisms (SNPs) were analyzed using MassARRAY iPLEX and Taqman assays. Results were analyzed using Haploview.

RESULTS

Three polymorphisms were disease-associated. IGF1 SNP rs6214 was associated with BE (adjusted P = .039). Using GG genotype as reference, odds ratio for BE in AA (wild-type) was 0.43 (95% confidence interval [CI], 0.24-0.75). GH receptor SNP rs6898743 was associated with EAC (adjusted P = .0112). With GG as reference, odds ratio for EAC in CC (wild-type) genotype was 0.42 (95% CI, 0.23-0.76). IGF1 (CA)(17) 185-bp allele was associated with RE (adjusted P = .0116). Using IGF1(non17) as reference, odds ratio for RE in IGF1(17) carriers was 7.29 (95% CI, 1.57-46.7).

CONCLUSIONS

In this study, 3 polymorphisms of IGF genes were associated with EAC or its precursors. These polymorphisms may be markers of disease risk; independent validation of our findings is required. These results suggest the IGF pathway is involved in EAC development.

Endogenous nerve growth factor regulates collagen expression and bladder hypertrophy through Akt and MAPK pathways during cystitis

Type I collagen forms the main constituent of the extracellular matrix in visceral organs. We reported here that cyclophosphamide (CYP)-induced cystitis significantly increased the production of type I collagen in the inflamed bladder leading to increases in the bladder weight and the thickness of the bladder wall. The endogenous nerve growth factor (NGF) in the urinary bladder regulated type I collagen expression because the neutralizing NGF antibody attenuated cystitis-induced type I collagen up-regulation in the inflamed bladder. Neutralizing NGF antibody also subsequently reversed cystitis-induced increases in bladder weight. Further studies on the intermediate signaling pathways mediating NGF-induced type I collagen expression in the inflamed bladder during cystitis revealed that Akt, JNK, and ERK1/2 activities were increased in the inflamed bladder, whereas p38 MAPK remained unchanged. Suppression of endogenous NGF level with neutralizing NGF antibody significantly blocked the increased activity of Akt, JNK, and ERK1/2 in the inflamed bladder during cystitis. These results indicate that endogenous NGF plays an important role in the activation of Akt and MAPK in the urinary bladder and in bladder hypertrophy during cystitis.

Effect of growth hormone on small intestinal homeostasis relation to cellular mediators IGF-I and IGFBP-3

AIM

To evaluate the effects of growth hormone (GH) on the histology of small intestines which might be related to the role of insulin like growth factor (IGF)-I, IGF-binding protein 3 (IGFBP-3) and its receptors.

METHODS

Twelve week-old adult male Wistar albino rats were divided into two groups. The study group (n = 10), received recombinant human growth hormone (rGH) at a dose of 2 mg/kg per day subcutaneously for 14 d and the control group (n = 10) received physiologic serum. Paraffin sections of jejunum were stained with periodic acid shift (PAS) and hematoxylin and eosin (HE) for light microscopy. They were also examined for IGF-I, IGFBP-3 and IGF-receptor immunoreactivities. Staining intensity was graded semi-quantitatively using the HSCORE.

RESULTS

Goblet cells and the cells in crypt epithelia were significantly increased in the study group compared to that of the control group. We have demonstrated an increase of IGF-I and IGFBP-3 immunoreactivities in surface epithelium of the small intestine by GH application. IGF-I receptor immunoreactivities of crypt, villous columnar cells, enteroendocrine cells and muscularis mucosae were also more strongly positive in the study group compared to those of in the control group.

CONCLUSION

These findings confirm the important trophic and protective role of GH in the homeostasis of the small intestine. The trophic effect is mediated by an increase in IGF-I synthesis in the small intestine, but the protective effect is not related to IGF-I.

Obestatin/ghrelin ratio: a new activity index in inflammatory bowel diseases

BACKGROUND

The aim was to determine obestatin and ghrelin serum levels and their ratio in inflammatory bowel disease (IBD) patients.

METHODS

We measured the ghrelin and obestatin levels of 31 Crohn's disease patients and 22 patients with ulcerative colitis using a radioimmunoassay method. Circulating levels of the 2 hormones and their ratio were correlated with the disease type and activity, disease localization, and treatment.

RESULTS

The mean ghrelin value was statistically significantly higher in patients with active disease (402.4 +/- 462.6 pg/mL) than in patients in remission (148.2 +/- 59.6 pg/mL) P = 0.0290, alpha = 0.05, whereas obestatin mean values were not (217.4 +/- 59.8 pg/mL in active disease and 189.0 +/- 46.8 pg/mL in patients with inactive disease P = 0.0607). When we evaluated the obestatin/ghrelin ratio between active and inactive disease, it was found that the ratio in active disease was statistically significantly lower (0.8 +/- 0.3) than in patients in remission (1.4 +/- 0.3) P < 0.001, alpha = 0.05. There is also a statistically significantly correlation between obestatin/ghrelin ratio and disease activity (P < 0,001).

CONCLUSIONS

Ghrelin and obestatin seem to play a significant role in IBD pathogenesis. Further studies are needed to elucidate the role of these hormones as new biological markers of activity of IBD.

Growth factors as treatment for inflammatory bowel disease: a concise review of the evidence toward their potential clinical utility

In the process of inflammation and repair of the intestinal mucosa in inflammatory bowel disease (IBD), there occurs a complex and an unknown interplay of innate and adaptive immune mechanisms. This interaction of factors may explain why IBD is characterized by a relapsing and remitting clinical course. Different components of innate immunity, hormones and interleukins in IBD have been suggested to be impaired. The growth hormone, epidermal growth factor, keratinocyte growth factor and colony-stimulating factors have emerged as potential tools for the modulation of intestinal inflammation and repair. Despite promising results of initial studies, the evidence that justify treatment of patients in clinical practice is not enough as some of the trials are nonrandomized or included a small number of patients. In this concise review, we provide a summary of the most recent and relevant evidence regarding the potential therapeutic effects of growth factors in IBD.

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.

TGF-beta1 and IGF-1 and anastomotic recurrence of Crohn's disease after ileo-colonic resection

BACKGROUND

After bowel resection, Crohn's disease (CD) recurs frequently in the site of the anastomosis. Alteration of normal healing processes may play a role in this phenomenon. Transforming growth factor beta (TGF-beta) and insulin-like growth factor (IGF-1) are involved in wound healing mechanisms with pro-fibrogenic properties. The aim of this study was to assess the expression of TGF-beta1 and insulin-like growth factor 1 (IGF-1) in the different zones of the bowel wall to understand why side-to-side anastomosis are associated to a lower recurrence rate compared to end-to-end ones.

PATIENTS AND METHODS

Seventeen patients affected by CD who underwent ileo-colonic resection from 2004 to 2005 were enrolled in this study. Full-thickness tissue samples were obtained from the mesenteric, the lateral, and the anti-mesenteric sides of the macroscopically diseased and healthy ileum for each patient. TGF-beta1 and IGF-1 messenger RNAs (mRNAs) were quantified by real-time polymerase chain reaction. Myeloperoxidase activity and histological disease activity were assessed to quantify the ileal inflammation. Vimentin, desmin, and alpha-smooth muscle actin were stained with immunohistochemistry to assess the fibroblast, smooth muscle cell, and myofibroblasts populations. Comparisons and correlations were carried out with nonparametric tests.

RESULTS

In diseased ileum, TGF-beta1 mRNA transcripts in the antimesenteric side were significantly lower than those of the mesenteric side (p = 0.05), and a significant correlation between TGFbeta-1 levels in diseased bowel and the sampling site was observed (tau = 0.36, p = 0.03). On the contrary, neither the IGF-1 mRNA transcripts nor the distribution of fibroblast, smooth muscle cell, and myofibroblasts populations showed any relation with the sampling site.

CONCLUSION

TGF-beta1 mRNA expression was lower in the anti-mesenteric side of the diseased ileum, and this was consistent with the success of side-to-side anastomosis in preventing CD recurrence. Since high expression of TGF-beta1 was associated to early recurrence, it seems rationale to construct the anastomosis on the anti-mesenteric side of the bowel.

Roles of TGF-β/CTGF in intestinal fibrosis

Intestinal fibrosis is a serious complication of many inflammatory bowel diseases and is mainly caused by excessive proliferation of intestinal mesenchymal cells and abnormal deposition of extracellular matrix (ECM). Transforming growth factor beta (TGF-β) plays a key role in the development of intestinal fibrosis. Connective tissue growth factor(CTGF) is the specific downstream mediator in many of the important fibroproliferative effects of TGF-β. TGF-β-induced CTGF expression is mediated through several signaling pathways. This paper reviewed the current knowledge about the formation mechanism of intestinal fibrosis and discussed roles of TGF-β/CTGF in this progression.

Anti-aging therapy with human growth hormone associated with metastatic colon cancer in a patient with Crohn's colitis

BACKGROUND & AIMS

The nonapproved use of human growth hormone (HGH) for anti-aging has been increasing. Theoretical concerns for neoplastic potentiation by HGH have been raised, but not proven clinically.

METHODS

We report the case of a 68-year-old man with colonic Crohn's disease who was found to have aggressive metastatic colon cancer. The patient had been receiving HGH therapy for anti-aging purposes for 7 years before presentation. Normal and malignant colonic tissue was examined for qualitative and quantitative molecular profiles of growth hormone (GH) and its signaling molecules, using immunohistochemistry and RNA extraction with polymerase chain reaction amplification.

RESULTS

Immunoreactivity was more robust in tumor tissue than in normal colon for insulin-like growth factor-1 receptor (IGF-1R) but not for IGF, GH, or GH receptor. RNA extraction with quantitative polymerase chain reaction showed that IGF-1R and vascular endothelial growth factor expression, but not IGF-1, GH receptor, or suppressor of cytokine signaling-2, were higher in tumor than in normal colonic tissue.

CONCLUSIONS

Colorectal cancer development concurrent with administration of HGH for anti-aging purposes occurred in an individual already at increased risk for colon cancer. This underscores the need for further investigation of the proneoplastic potential of GH supplementation for anti-aging.

Divergent metabolic adaptations to intestinal parasitic nematode infection in mice susceptible or resistant to obesity

BACKGROUND & AIMS

Diet-induced obesity results from increased ingestion of energy-dense food and sedentary lifestyle in genetically susceptible individuals. An environmental factor that may have shaped our energy homeostasis throughout evolution is parasitic nematode infection.

METHODS

To test the hypothesis that a metabolically "thrifty phenotype" is advantageous during intestinal nematode infection, we compared the responses to Heligmosomoides polygyrus infection between 2 mouse strains: obesity-prone C57Bl/6J vs obesity-resistant SWR/J. Metabolic phenotyping was performed using indirect calorimetry, dual energy x-ray absorptiometry, and magnetic resonance imaging scanning. Gene expression was assessed by quantitative reverse-transcription polymerase chain reaction and immunohistochemistry.

RESULTS

Body weight was maintained in both strains during nematode infection via different mechanisms. There was no apparent change in energy expenditure between the strains; however, SWR/J mice exhibited a marked hyperphagia (calorie intake 60% higher than C57Bl/6J) to maintain body weight. The importance of hyperphagia was confirmed by severe weight loss in a group of infected SWR/J mice whose food intake was restricted to that of naïve mice. Furthermore, SWR/J mice expelled nematodes more rapidly than C57Bl/6J mice, an effect related to a T helper cell 2 immune response.

CONCLUSIONS

C57Bl/6J mice are more energy efficient during parasitic nematode infection, which may explain their ability to tolerate the infection. SWR/J mice, on the other hand, require an increase in food intake to maintain energy stores during nematode infection. In addition, a strong T helper cell 2-mediated immune response that facilitates a prompt clearance of nematode infection in SWR/J mice may have evolved to conserve energy in this strain.

Systemic metabolic effects of combined insulin-like growth factor-I and growth hormone therapy in patients who have sustained acute traumatic brain injury

OBJECT

Hypermetabolism, hypercatabolism, refractory nitrogen wasting, hyperglycemia, and immunosuppression accompany traumatic brain injury (TBI). Pituitary dysfunction occurs, affecting growth hormone (GH) and plasma insulin-like growth factor-I (IGF-I) concentrations. The authors evaluated whether combination IGF-I/GH therapy improved metabolic and nutritional parameters after moderate to severe TBI.

METHODS

The authors conducted a prospective, randomized, double-blind study comparing combination IGF-I/GH therapy and a placebo treatment. Ninety-seven patients with TBI were enrolled in the study within 72 hours of injury and were assigned to receive either combination IGF-I/GH therapy or placebo. All patients received concomitant nutritional support. Insulin-like growth factor-I was administered by continuous intravenous infusion (0.01 mg/kg/hr), and GH (0.05 mg/kg/day) was administered subcutaneously. Placebo control group patients received normal saline solution in place of both agents. Nutritional and metabolic monitoring continued throughout the 14-day treatment period. The two groups did not differ in energy expenditure, nutrient intake, or use of insulin treatment. The mean daily serum glucose concentration was higher in the treatment group (123 +/- 24 mg/dl) than in the control group (104 +/- 11 mg/dl) (p < 0.03). A positive nitrogen balance was achieved within the first 24 hours in the treatment group and remained positive in that group throughout the treatment period (p < 0.05). This pattern was not observed in the control group. Plasma IGF-I concentrations were above 350 ng/ml in the treatment group throughout the study period. Overall, the mean plasma IGF-I concentrations were 1003 +/- 480.6 ng/ml in the treatment group and 192 +/- 46.2 ng/ml in the control group (p < 0.01).

CONCLUSIONS

The combination of IGF-I and GH produced sustained improvement in metabolic and nutritional endpoints after moderate to severe acute TBI.

The insulin-like growth factor (IGF)-system in active ulcerative colitis and Crohn's disease: relations to disease activity and corticosteroid treatment

BACKGROUND

Metabolic bone disease (MBD) and muscle wasting (MW) are serious complications in adults suffering from inflammatory bowel disease (IBD). The inflammatory process and corticosteroid treatment may lead to changes in the IGF-system associated with MBD and MW.

AIM

To assess changes in the IGF-system and clinical and biochemical markers in ulcerative colitis (UC) and Crohn's disease (CD).

METHODS

We studied 37 IBD patients with severe clinical exacerbation (20 with UC, 17 with CD) before and during high dose corticosteroid treatment and tapering (8-12 weeks).

RESULTS

Total IGF-I was reduced in CD (36% p<0.01) and UC (41% p<0.001) before treatment and normalized completely. Free IGF-I baseline levels were unchanged compared to controls. In UC, free IGF-I levels increased significantly at week 1 and week 4 (p<0.01, respectively). In CD, no changes in free IGF-I levels were observed. IGFBP-2 baseline levels were increased by a factor 2.3 in UC and CD compared to controls (p<0.01 respectively) and normalized during treatment. IGFBP-3 was reduced by 38% (p<0.01) in CD and 32% (p<0.01) in UC with only partial normalization. Harvey-Bradshaw index, C - reactive protein and albumin normalized during treatment.

CONCLUSIONS

Significant changes in total and free IGF-I and IGFBP-2 and IGFBP-3 were demonstrated in CD and UC patients in exacerbation with only partial normalization during high dose corticosteroid treatment and tapering without differences between UC and CD. These changes may be part of MBD and MW in active IBD.

Increased expression of midkine in the rat colon during healing of experimental colitis

Midkine (MK) is a unique growth and differentiation factor that modulates the proliferation and migration of various cells; however, little is known regarding its relationship to intestinal diseases. The aim of this study was to investigate MK expression and its role in dextran sulfate sodium (DSS)-induced colitis in rats. The expressions of MK, receptor-like protein-tyrosine phosphatase (RPTP)-beta, and proinflammatory cytokines were examined in rat colonic tissues after the development of DSS-induced colitis using Northern blotting, immunohistochemistry, and laser-capture microdissection (LCM) coupled with RT-PCR. The effects of MK on the migration of intestinal epithelial cells (IEC-6) were also evaluated in vitro using an intestinal wound repair model. MK expression was significantly increased in damaged colonic mucosa, mainly from day 3 to day 5 after the end of DSS administration, with abundant MK immunoreactive signals detected in submucosal fibroblasts. Expressions of proinflammatory cytokines were most strongly induced on day 1, which preceded the augmentation of MK expression. Results of LCM coupled with RT-PCR clearly indicated RPTP-beta expression in colonic epithelial cells. The migration assay showed that wound repair in the MK-treated groups was accelerated dose dependently. The present results showed for the first time that intestinal inflammation upregulates the MK-RPTP-beta system, which may stimulate mucosal regeneration during the process of healing of colitis. Additional investigations regarding the role of MK may contribute to the development of new options for the treatment of inflammatory bowel diseases.

The essential role of insulin-like growth factor-1 in the intestinal tropic effects of glucagon-like peptide-2 in mice

BACKGROUND & AIMS

Glucagon-like peptide-2 (GLP-2) is an intestinal hormone that acts through unknown pathways to induce intestinal growth. We investigated the role of the insulin-like growth factors (IGF-1 and IGF-2) as mediators of GLP-2-enhanced growth in the murine intestine.

METHODS

IGF-1 expression and secretion were determined in GLP-2-responsive primary intestinal cultures treated with GLP-2. Parameters of intestinal growth were assessed in wild-type (CD1, Igf1(+/+) and Igf2+), heterozygous (Igf1(+/-)), and null (Igf1(-/-) and Igf2(-P)) mice treated chronically with saline, GLP-2, IGF-1, or R-Spondin1.

RESULTS

GLP-2 increased IGF-1 messenger RNA expression and IGF-1 secretion in intestinal cultures and increased expression of IGF-1 messenger RNA in mouse small intestine in vivo. Igf1(+/+) and Igf2+ mice responded to .1 microg/g(-1) per day(-1) GLP-2 with increased intestinal weights, morphometric parameters, and proliferative indices. In contrast, Igf1(-/-) mice were unresponsive to the same dose of GLP-2, failing to demonstrate changes in intestinal weight, morphometry, or proliferation. However, a significant effect of 1 microg/g(-1) per day(-1) GLP-2 was observed in Igf1(-/-) mice, but only in terms of small intestinal weight when normalized for body weight. Furthermore, Igf2(-P) mice demonstrated a partially impaired response in terms of small intestinal growth. Both Igf1(-/-) and Igf2(-P) mice exhibited normal-enhanced intestinal growth in response to IGF-1 and/or R-Spondin1.

CONCLUSIONS

GLP-2 enhances intestinal IGF-1 expression and secretion, and IGF-1 is required for small and large intestinal growth in response to GLP-2. These findings identify IGF-1 as an essential mediator of the intestinotropic actions of GLP-2.

New growth factor therapies aimed at improving intestinal adaptation in short bowel syndrome

Short bowel syndrome (SBS) is used to describe a condition of malabsorption and malnutrition resulting from the loss of absorptive area following massive small bowel resection. The key to improved clinical outcome after massive small bowel resection is the ability of the residual bowel to adapt. Although still in experimental stages, a major goal in the management of SBS may be the augmented use of growth factors to promote increased adaptation. A number of growth factors have been implicated in promoting the adaptation process. The best-described growth factors are reviewed: glucagon-like peptide-2 (GLP-2), epidermal growth factor (EGF), and growth hormone (GH). This article reviews the ability of recombinant GLP-2, EGF and GH to modulate structural and functional aspects of intestinal adaptation following small bowel resection. Although these growth factors have shown promise, small sample size, inconsistent measurement parameters and uncontrolled study designs have hampered the acquisition of strong data advocating the use of growth factor treatment for SBS. Multicenter trials using well-defined outcome measures to assess clinical efficacy are needed to direct the clinical indications, timing and duration of therapy and assess potential risks associated with growth factor therapies.

Therapeutic action of ghrelin in a mouse model of colitis

BACKGROUND & AIMS

Ghrelin is a novel growth hormone-releasing peptide with potential endogenous anti-inflammatory activities ameliorating some pathologic inflammatory conditions. Crohn's disease is a chronic debilitating disease characterized by severe T helper cell (Th)1-driven inflammation of the colon. The aim of this study was to investigate the therapeutic effect of ghrelin in a murine model of colitis.

METHODS

We examined the anti-inflammatory action of ghrelin in the colitis induced by intracolonic administration of trinitrobenzene sulfonic acid. Diverse clinical signs of the disease were evaluated, including weight loss, diarrhea, colitis, and histopathology. We also investigated the mechanisms involved in the potential therapeutic effect of ghrelin, such as inflammatory cytokines and chemokines, Th1-type response, and regulatory factors.

RESULTS

Ghrelin ameliorated significantly the clinical and histopathologic severity of the trinitrobenzene sulfonic acid-induced colitis; abrogating body weight loss, diarrhea, and inflammation; and increasing survival. The therapeutic effect was associated with down-regulation of both inflammatory and Th1-driven autoimmune response through the regulation of a wide spectrum of inflammatory mediators. In addition, a partial involvement of interluekin-10/transforming growth factor-beta1-secreting regulatory T cells in this therapeutic effect was demonstrated. Importantly, the ghrelin treatment was therapeutically effective in established colitis and avoided the recurrence of the disease.

CONCLUSIONS

Our data demonstrate novel anti-inflammatory actions for ghrelin in the gastrointestinal tract, ie, the capacity to deactivate the intestinal inflammatory response and to restore mucosal immune tolerance at multiple levels. Consequently, ghrelin administration represents a novel possible therapeutic approach for the treatment of Crohn's disease and other Th1-mediated inflammatory diseases, such as rheumatoid arthritis and multiple sclerosis.

[Example of safety measures for antineoplastic agents immediately after market launch--a case of TS-1 capsule all example use result investigation that executes safety monitoring--]

As a measure to ensure safe use of TS-1 during the early marketing period, a drug use investigation was conducted on an all-case basis. Extra safety monitoring,rarely included in the use investigation,was also planned for patients who began therapy with this agent. Of the 4,177 subjects registered during the year beginning in March 1999, 3,882 started TS-1 therapy. Aside from 74 dropouts, 3,808 cases were evaluable for safety. The overall incidence of adverse reactions, with high frequencies of myelosuppression and gastrointestinal disorders, was 74.3%: a result similar to an incidence of 77.5% (100/129) found in the early phase II trial with gastric cancer patients. Safety monitoring made it possible to check if a given patients was eligible for proper use before treatment is begun. During TS-1 administration,collaboration was formed between physicians and medical representatives to ensure regular laboratory testing and to check the test findings. Measures were considered necessary to secure the safe use of drugs with manifest risk of serious adverse reactions, such as antineoplastic agents, during the initial period of market introduction. Our present approach proved effective as one of such measures.

Suppressor of cytokine signaling-2 modulates the fibrogenic actions of GH and IGF-I in intestinal mesenchymal cells

Growth hormone (GH) and IGF-I play important roles in wound healing during intestinal injury and inflammation, but there is also indirect evidence that locally expressed IGF-I may act to induce excessive collagen deposition, which can lead to intestinal fibrosis. Factors that dictate the balance between normal wound healing and excessive healing responses are unknown. Using RNase protection assay and in situ hybridization, we determined whether GH and/or IGF-I increase type I collagen deposition in the intestine of rats fed by total parenteral nutrition (TPN), a feeding modality used for many patients following intestinal surgery and resection. We also used an in vitro model system to confirm our in vivo effects and to directly evaluate the relative potency of GH and IGF-I on DNA synthesis and collagen deposition in intestinal myofibroblasts. Both GH and IGF-I stimulated collagen production in vivo and in vitro, and IGF-I, but not GH, stimulated DNA synthesis in vitro. In collagen production, GH was less potent than IGF-I. Suppressors of cytokine signaling (SOC) are cytokine-inducible proteins that negatively feedback to inhibit the actions of cytokines and we recently found that GH selectively upregulates SOC-2 in the intestine of TPN-fed rats. We examined whether SOC-2 may be responsible for the difference in magnitude of action of GH and IGF-I on collagen accumulation. GH, but not IGF-I, induced SOC-2 in isolated myofibroblasts, and overexpression of SOC-2 led to a suppression of GH- and IGF-I-induced collagen accumulation. SOC-2 null mice infused with IGF-I showed greater collagen gene expression compared with wild-type (WT) mice. Myofibroblasts isolated from SOC-2 null mice showed increased IGF-I-stimulated DNA synthesis compared with WT cells. Taken together, these findings suggest that SOC-2 induced by GH may play an important role in suppressing collagen accumulation and mesenchymal cell proliferation induced by GH or GH-induced IGF-I, providing a mechanism for the differing potencies of GH and IGF-I on intestinal mesenchyme and collagen synthesis.

Growth hormone inhibits signal transducer and activator of transcription 3 activation and reduces disease activity in murine colitis

BACKGROUND & AIMS

Constitutive signal transducer and activator of transcription (STAT) 3 activation promotes chronic inflammation and epithelial proliferation in murine colitis and human inflammatory bowel disease. SHP-2, through binding to the glycoprotein 130 signaling receptor, negatively regulates STAT3 activation. Growth hormone reduces disease activity and promotes mucosal healing in colitis and can activate SHP-2.

METHODS

We hypothesized that growth hormone administration would reduce disease activity in experimental colitis and that this would involve modulation of SHP-2/glycoprotein 130 association and STAT3 activation.

RESULTS

Growth hormone administration improved weight gain and colon histology in interleukin 10-null mice with colitis. Growth hormone reduced apoptosis and increased proliferation of crypt epithelial cells while increasing apoptosis of lamina propria mononuclear cells. Growth hormone increased SHP-2/glycoprotein 130 association and reduced colonic STAT3 activation in interleukin 10-null mice and in biopsy samples from patients with Crohn's colitis. Expression of the antiapoptotic protein bcl-2 was increased in crypt epithelial cells after growth hormone treatment. Growth hormone increased SHP-2/glycoprotein 130 binding and reduced interleukin 6-dependent STAT3 activation in the T84 human colon carcinoma and Jurkat human T-cell leukemia lines.

CONCLUSIONS

Growth hormone administration improves weight gain and reduces disease activity in interleukin 10-null mice with colitis. The improvement in disease activity is associated with increased SHP-2/glycoprotein 130 binding and reduced STAT3 activation in both murine and Crohn's colitis. Growth hormone may be a useful therapy in inflammatory bowel disease, in terms of both improving anabolic metabolism and enhancing mucosal healing.

Infliximab reverses growth hormone resistance associated with inflammatory bowel disease

BACKGROUND

Increasing evidence shows that inflammation plays a major role in the aetiology of catabolism and wasting observed in inflammatory bowel disease via growth hormone resistance.

AIM

To evaluate the effect of infliximab treatment on the growth hormone/insulin-like growth factor-1 axis.

METHODS

Fourteen adults with active Crohn's disease or ulcerative colitis underwent three infliximab infusions at a dose of 5 mg/kg for induction of remission, plus two maintenance infusions 8 weeks apart. Blood samples were collected for the analysis of serum growth hormone, insulin-like growth factor-1, insulin-like growth factor-binding protein-3 and acid labile subunit.

RESULTS

Serum insulin-like growth factor-1 and insulin-like growth factor-binding protein-3 concentrations, which were significantly lower in inflammatory bowel disease patients before treatment compared with controls (P < 0.01), significantly increased during the induction phase (+58% and +29%, respectively, after the second infusion, P < 0.01), and dropped to baseline levels during maintenance therapy. Both insulin-like growth factor-1 and insulin-like growth factor-binding protein-3 showed significant negative correlations with C-reactive protein (rho = -0.37, P = 0.002; rho = -0.35, P = 0.01, respectively). Growth hormone and acid labile subunit levels were not statistically different between controls and inflammatory bowel disease patients either at baseline or during treatment.

CONCLUSIONS

Infliximab induction treatment reverses growth hormone resistance observed in active inflammatory bowel disease through the suppression of systemic inflammation. The restored growth hormone/insulin-like growth factor-1 axis is impaired again following the prolonged interval between maintenance infusions, possibly because of the subclinical reactivation of the inflammatory process.