Altered expression of type I insulin-like growth factor receptor in Crohn's disease

Intestinal Stromal Cells in the Turmoil of Inflammation and Defective Connective Tissue Remodeling in Inflammatory Bowel Disease

In steady state, intestinal subepithelial myofibroblasts form a thin layer below the basement membrane. Unlike the rest of the stromal cells in the lamina propria, they express tensile proteins, guide epithelial regeneration, and sense luminal microbiota. Upon inflammation in inflammatory bowel disease (IBD), they express activation markers, accept trophic signaling by infiltrating neutrophils and macrophages, and are activated by cytokines from helper T cells to produce a narrow spectrum of cytokines and a wider spectrum of chemokines, attract cells of innate and adaptive immunity, orchestrate inflammatory responses, and qualitatively and quantitatively modify the extracellular matrix. Thus, beyond being structural tissue components, they assume active roles in the pathogenesis of complicated IBD. Discrimination between myofibroblasts and fibroblasts may be an oversimplification in light of single-cell sequencing data unveiling the complexity of multiple phenotypes of stromal cells with distinct roles and plasticity. Spatial transcriptomics revealed distinct phenotypes by histologic localization and, more intriguingly, the assembly of mucosal neighborhoods that support spatially distinct functions. Current IBD treatments target inflammation but fail in fibrostenotic or fistulizing disease. Baseline and recent findings on stromal cells, molecules, and pathways involved in disrupted extracellular matrix homeostasis are reviewed to provide relevant pharmacologic targets.

Crossroad between Obesity and Gastrointestinal Cancers: A Review of Molecular Mechanisms and Interventions

The burden of gastrointestinal (GI) cancer is increasing worldwide, and in the past decade, cancer had entered the list of chronic debilitating diseases whose risk is substantially increased by hypernutrition. Obesity may increase the risk of cancer by the imbalance of various mechanisms including insulin and insulin-like growth factor1 (IGF-I) signaling, systemic inflammation, immune dysregulation, tumor angiogenesis, adipokines secretion, and intestinal microbiota that usually act interdependently. An increased understanding of the mechanisms underlying obesity-GI cancer link can provide multiple opportunities for cancer prevention. This review discusses various mechanisms involved molecular mechanisms linking obesity with GI cancers including esophagus, stomach, colorectal and hepatocellular. Furthermore, an optional intervention such as diet restriction and exercise is described, which may be preventive or therapeutic in GI cancer.

An integrative network-based approach to identify novel disease genes and pathways: a case study in the context of inflammatory bowel disease

BACKGROUND

There are different and complicated associations between genes and diseases. Finding the causal associations between genes and specific diseases is still challenging. In this work we present a method to predict novel associations of genes and pathways with inflammatory bowel disease (IBD) by integrating information of differential gene expression, protein-protein interaction and known disease genes related to IBD.

RESULTS

We downloaded IBD gene expression data from NCBI's Gene Expression Omnibus, performed statistical analysis to determine differentially expressed genes, collected known IBD genes from DisGeNet database, which were used to construct a IBD related PPI network with HIPPIE database. We adapted our graph-based clustering algorithm DPClusO to cluster the disease PPI network. We evaluated the statistical significance of the identified clusters in the context of determining the richness of IBD genes using Fisher's exact test and predicted novel genes related to IBD. We showed 93.8% of our predictions are correct in the context of other databases and published literatures related to IBD.

CONCLUSIONS

Finding disease-causing genes is necessary for developing drugs with synergistic effect targeting many genes simultaneously. Here we present an approach to identify novel disease genes and pathways and discuss our approach in the context of IBD. The approach can be generalized to find disease-associated genes for other diseases.

Relation of the IGF/IGF1R system to autophagy in colitis and colorectal cancer

Metabolic syndrome (MetS), as a chronic inflammatory disorder has a potential role in the development of inflammatory and cancerous complications of the colonic tissue. The interaction of DNA damage and inflammation is affected by the insulin-like growth factor 1 receptor (IGF1R) signaling pathway. The IGF1R pathway has been reported to regulate autophagy, as well, but sometimes through a bidirectional context. Targeting the IGF1R-autophagy crosstalk could represent a promising strategy for the development of new antiinflammatory and anticancer therapies, and may help for subjects suffering from MetS who are at increased risk of colorectal cancer. However, therapeutic responses to targeted therapies are often shortlived, since a signaling crosstalk of IGF1R with other receptor tyrosine kinases or autophagy exists, leading to acquired cellular resistance to therapy. From a pharmacological point of view, it is attractive to speculate that synergistic benefits could be achieved by inhibition of one of the key effectors of the IGF1R pathway, in parallel with the pharmacological stimulation of the autophagy machinery, but cautiousness is also required, because pharmacologic IGF1R modulation can initiate additional, sometimes unfavorable biologic effects.

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.

Oxidative stress in obesity: a critical component in human diseases

Obesity, a social problem worldwide, is characterized by an increase in body weight that results in excessive fat accumulation. Obesity is a major cause of morbidity and mortality and leads to several diseases, including metabolic syndrome, diabetes mellitus, cardiovascular, fatty liver diseases, and cancer. Growing evidence allows us to understand the critical role of adipose tissue in controlling the physic-pathological mechanisms of obesity and related comorbidities. Recently, adipose tissue, especially in the visceral compartment, has been considered not only as a simple energy depository tissue, but also as an active endocrine organ releasing a variety of biologically active molecules known as adipocytokines or adipokines. Based on the complex interplay between adipokines, obesity is also characterized by chronic low grade inflammation with permanently increased oxidative stress (OS). Over-expression of oxidative stress damages cellular structures together with under-production of anti-oxidant mechanisms, leading to the development of obesity-related complications. The aim of this review is to summarize what is known in the relationship between OS in obesity and obesity-related diseases.

Resveratrol inhibits collagen I synthesis by suppressing IGF-1R activation in intestinal fibroblasts

AIM: To investigate whether resveratrol (3,4,5-trihydroxy-trans-stilbene) inhibits collagen I synthesis induced by insulin growth factor-1 (IGF-1) in intestinal fibroblasts, and to explore the possible molecular mechanisms.

METHODS: Male Sprague-Dawley rats were randomly divided into two groups: a control group and a 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis group. After 21 d of TNBS administration, the degree of inflammation and fibrosis in colon was measured by HE staining and Masson’s trichrome staining. Western blotting was used to examine collagen I, IGF-1 and silent information regulator 1 (SIRT1) protein expression in colitis tissues. Western blotting and quantitative real-time polymerase chain reaction were used to characterize collagen I protein and col1a2 mRNA expression in mouse intestinal fibroblasts and CCD-¹⁸Co cells treated with IGF-1. A MEK inhibitor (U0126) was used to determine whether IGF-1-induced collagen I expression was mediated by extracellular signal-regulated kinase 1/2 (ERK1/2)-dependent mechanism. Effects of resveratrol on collagen I protein level, insulin growth factor-1 receptor (IGF-1R) and ERK1/2 phosphorylation levels were also examined after IGF-1 treatment in fibroblasts. To evaluate whether SIRT1 was necessary for the anti-fibrosis effect of resveratrol, cells were transfected with SIRT1-specific small interfering RNAs, wild-type SIRT1, and deacetylase-inactive mutant SIRT1.

RESULTS: Collagen I and IGF-1 expression was increased, and SIRT1 expression was decreased (0.67 ± 0.04 vs 1.05 ± 0.07, P < 0.001) in TNBS-induced colitis compared with the control group. In vitro, IGF-1 could induce collagen I expression, mainly through the ERK 1/2 signal pathway. Resveratrol reduced basal and IGF-1-induced collagen I gene and protein expression in intestinal fibroblasts. Overexpression of wild-type SIRT1, not deacetylase-inactive mutant SIRT1, decreased expression of collagen I induced by IGF-1. Moreover, silencing SIRT1 restored collagen I expression in fibroblasts challenged with resveratrol. However, disruption of SIRT1 did not influence the anti-fibrotic effects of resveratrol and IGF-1-induced collagen I expression. Further analysis revealed that resveratrol significantly decreased phosphorylation of IGF-1R and its downstream signaling molecules by inhibiting IGF-1 binding to its receptor.

CONCLUSION: Our data suggest that resveratrol effectively inhibits collagen I synthesis in IGF-1-stimulated fibroblasts, partly by inhibiting IGF-1R activation, and SIRT1 is also responsible for the process.

Mechanisms of obesity-induced gastrointestinal neoplasia

Obesity is among the fastest growing diseases worldwide; treatment is inadequate, and associated disorders, including gastrointestinal cancers, have high morbidity and mortality. An increased understanding of the mechanisms of obesity-induced carcinogenesis is required to develop methods to prevent or treat these cancers. In this report, we review the mechanisms of obesity-associated colorectal, esophageal, gastric, and pancreatic cancers and potential treatment strategies.

Monosodium glutamate-induced diabetic mice are susceptible to azoxymethane-induced colon tumorigenesis

Obese people and diabetic patients are known to be high risk of colorectal cancer (CRC), suggesting need of a new preclinical animal model, by which to extensively study the diverse mechanisms, therapy and prevention. The present study aimed to determine whether experimental obese and diabetic mice produced by monosodium glutamate (MSG) treatment are susceptible to azoxymethane (AOM)-induced colon tumorigenesis using early biomarkers, aberrant crypts foci (ACF) and β-catenin-accumulated crypts (BCACs), of colorectal carcinogenesis. Male Crj:CD-1 (ICR) newborns were daily given four subcutaneous injections of MSG (2 mg/g body wt) to induce diabetes and obesity. They were then given four intraperitoneal injections of AOM (15 mg/kg body wt) or saline (0.1 ml saline/10 g body wt). Ten weeks after the last injection of AOM, the MSG-AOM mice had a significant increase in the multiplicity of BCAC (13.83 ± 7.44, P < 0.002), but not ACF (78.00 ± 11.20), when compare to the Saline-AOM mice (5.45 ± 1.86 of BCAC and 69.27 ± 8.06 of ACF). Serum biochemical profile of the MSG-treated mice with or without AOM showed hyperinsulinemia, hypercholesteremia and hyperglycemia. The mRNA expression of insulin-like growth factor-1 receptor (IGF-1R, P<0.01) was increased in the MSG-AOM mice, when compared with the mice given AOM alone. IGF-1R was immunohistochemically expressed in the BCAC, but not ACF, in the AOM-treated mice. Our findings suggest that the MSG mice are highly susceptible to AOM-induced colorectal carcinogenesis, suggesting potential utility of our MSG-AOM mice for further investigation of the possible underlying events that affect the positive association between obese/diabetes and CRC.

Insulin-like growth factor I receptor density on CD4+T-lymphocytes from active early steroid- and DMARD-naïve rheumatoid arthritis patients is up-regulated and not influenced by 1 year of clinically effective treatment

The IGF-IR density on CD4+T-lymphocytes was studied using flow cytometry in 40 early steroid- and DMARD-naïve rheumatoid arthritis (RA) patients before and after 52 weeks of treatment with methotrexate+placebo or methotrexate+cyclosporine A and in 15 controls. RA patients had increased IGF-IR density on CD4+T-lymphocytes at week 0 and week 52, irrespective of treatment. IGF-IR-positive CD4+T-lymphocytes fraction decreased during treatment, but neither at week 0 nor at week 52 did it differ from healthy controls. No correlations were found to disease activity parameters.

Insulin-like growth factor-1 receptor transactivation modulates the inflammatory and proliferative responses of neurotensin in human colonic epithelial cells

Neurotensin (NT) is a gastrointestinal neuropeptide that modulates intestinal inflammation and healing by binding to its high-affinity receptor NTR1. The dual role of NT in inflammation and healing is demonstrated in models of colitis induced by Clostridium difficile toxin A and dextran sulfate sodium, respectively, and involves NF-κB-dependent IL-8 expression and EGF receptor-mediated MAPK activation in human colonocytes. However, the detailed signaling pathways involved in these responses remain to be elucidated. We report here that NT/NTR1 coupling in human colonic epithelial NCM460 cells activates tyrosine phosphorylation of the insulin-like growth factor-1 receptor (IGF-1R) in a time- and dose-dependent manner. NT also rapidly induces Src tyrosine phosphorylation, whereas pretreatment of cells with the Src inhibitor PP2 before NT exposure decreases NT-induced IGF-1R phosphorylation. In addition, inhibition of IGF-1R activation by either its specific antagonist AG1024 or siRNA against IGF-1 significantly reduces NT-induced IL-8 expression and NF-κB-dependent reporter gene expression. Pretreatment with AG1024 also inhibits Akt activation and apoptosis induced by NT. Silencing of Akt expression by siRNA also substantially attenuates NT-induced IL-8 promoter activity and NF-κB-dependent reporter gene expression. This is the first report to indicate that NT transactivates IGF-1R and that this response is linked to Akt phosphorylation and NF-κB activation, contributing to both pro-inflammatory and tissue repair signaling pathways in response to NT in colonic epithelial cells. We propose that IGF-1R activation represents a previously unrecognized key pathway involved in the mechanisms by which NT and NTR1 modulate colonic inflammation and inflammatory bowel disease.

Immunopathogenesis of thyroid eye disease: emerging paradigms

Graves disease represents a systemic autoimmune process targeting the thyroid, orbit, and pretibial skin. The thyroid dysfunction is treatable, but no consistently effective medical therapy has yet been described for the orbital manifestations of Graves disease, also known as thyroid-associated ophthalmopathy or thyroid eye disease. Several autoantigens are potentially relevant to the pathogenesis of thyroid eye disease. Activating antibodies generated against the thyrotropin receptor can be detected in a majority of patients, and these drive hyperthyroidism. However, stimulating antibodies against the insulin-like growth factor-1 receptor (IGF-1R) may also play a role in the extra-thyroid manifestations of Graves disease. IGF-1R is overexpressed by orbital fibroblasts derived from patients with thyroid eye disease, whereas IGF-1R(+) T and IGF-1R(+) B cells are considerably more frequent in Graves disease. Actions of several cytokines and the molecular interplay peculiar to the orbit appear to provoke the inflammation, fat expansion, and deposition of excessive extracellular matrix molecules in thyroid eye disease. Based upon these new insights, several therapeutic strategies can now be proposed that, for the first time, might specifically interrupt its pathogenesis.

Insulin-like growth factor-I regulation of immune function: a potential therapeutic target in autoimmune diseases?

This topically limited review explores the relationship between the immune system and insulin-like growth factors (IGF-I and IGF-II) and the proteins through which they act, including IGF-I receptor (IGF-IR) and the IGF-I binding proteins. The IGF/IGF-IR pathway plays important and diverse roles in tissue development and function. It regulates cell cycle progression, apoptosis, and the translation of proteins. Many of the consequences ascribed to IGF-IR activation result from its association with several accessory proteins that are either identical or closely related to those involved in insulin receptor signaling. Relatively recent awareness that IGF-I and IGF-IR regulate immune function has cast this pathway in an unexpected light; it may represent an important switch governing the quality and amplitude of immune responses. IGF-I/IGF-IR signaling may also participate in the pathogenesis of autoimmune diseases, although its relationship with these processes seems complex and relatively unexplored. On the one hand, IGF-I seems to protect experimental animals from developing insulin-deficient diabetes mellitus. In contrast, activating antibodies directed at IGF-IR have been detected in patients with Graves' disease, where the receptor is overexpressed by multiple cell types. The frequency of IGF-IR+ B and T cells is substantially increased in patients with that disease. Potential involvement of IGF-I and IGF-IR in the pathogenesis of autoimmune diseases suggests that this pathway might constitute an attractive therapeutic target. IGF-IR has been targeted in efforts directed toward drug development for cancer, employing both small-molecule and monoclonal antibody approaches. These have been generally well-tolerated. Recognizing the broader role of IGF-IR in regulating both normal and pathological immune responses may offer important opportunities for therapeutic intervention in several allied diseases that have proven particularly difficult to treat.

Regeneration associated growth factor receptor and epithelial marker expression in lymphoid aggregates of ulcerative colitis

OBJECTIVE

Mesenchymal-epithelial transition may have crucial role in mucosal regeneration, hence we assayed epithelial growth factor receptor (EGFR), insulin-like growth factor receptor-1 (IGF1R), hepatocyte-derived growth factor receptor (HGFR), CDX2 and cytokeratin (CK) expression in lymphoid aggregates (LA) of ulcerative colitis (UC).

MATERIAL AND METHODS

Tissue microarrays (TMAs) made of biopsy samples from 20 mildly, 20 moderately and 20 severely active UC, 12 non-specific colitis (NSC) and 20 healthy colon were prepared, and immunolabelled with anti-EGFR, -IGF1R, -HGFR, -CDX2, -CK antibodies. After virtual microscopic evaluation, one-way ANOVA and correlation analysis were performed. For validation, TaqMan real-time RT-PCR was performed by using RNA from laser microdissected LA from 10 healthy colon and 10 endoscopically active UC biopsies.

RESULTS

The number of LA was in tight positive correlation with the severity of inflammation (r=0.9). The number of EGFR/HGFR positive subepithelial cells was found to be significantly elevated in severe (21.6+/-2.1%/21.3+/-1.9%), moderate (14.3+/-1.7%/14.6+/-1.6%) and mild (7.2+/-1.6%/7.4+/-1.3%) inflammation compared to healthy colon mucosa (2.6+/-1.4%/2.4+/-1.03%) (p < 0.005). Some alterations were found between UC and NSC samples regarding EGFR and HGFR expression. IGF1R immunoreactive cells were only found in a trace number in all cases. Increasing trend of CDX2 and CK positive subepithelial cells was found in active UC, but it was not in significant correlation with the severity of inflammation.

CONCLUSION

EGFR and HGFR positive subepithelial cells in LA may be involved in the induction of the regenerative mucosal processes. The presence of CDX2/CK positive subepithelial cells suggests that mesenchymal-to-epithelial transition may be located to lymphoid aggregates.

IL-13 signaling via IL-13R alpha2 induces major downstream fibrogenic factors mediating fibrosis in chronic TNBS colitis

BACKGROUND & AIMS

Previous studies have shown that fibrosis developing in chronic experimental colitis is driven by interleukin (IL)-13 signaling via IL-13R alpha(2) and the production of transforming growth factor (TGF)-beta1. In the present study, we sought to determine the fibrogenic downstream events set in motion by such signaling.

METHODS

Experimental colitis with late-onset intestinal fibrosis was induced by weekly intrarectal administration of trinitrobenzene sulfonic acid (TNBS) to BALB/c mice. Blockade of IL-13 signaling via IL-13R alpha(2) and TGF-beta1 signaling was achieved by the administration of small interfering RNA or decoy oligonucleotides that target promoter sequences of signaling components of these receptors. Effects of blockade were determined by enzyme-linked immunosorbent assay or Western blotting detecting specific key fibrogenic factors and by measurement of collagen production.

RESULTS

Initially, we showed that abrogation of IL-13 activity via blockade of IL-13R alpha(2) and TGF-beta1 signaling results in severe inhibition of expression of colonic insulin-like growth factor (IGF)-I and early growth response gene (Egr)-1, factors known to initiate and sustain fibrosis. We then showed that Egr-1 was necessary early in the fibrotic process for caspase-mediated apoptosis of myofibroblasts and the production of urokinase plasminogen activator, a protein that enhances TGF-beta1 activation. Finally, we showed that IGF-I (together with TGF-beta1) acts later in the process to stimulate myofibroblasts to deposit collagen in the colon.

CONCLUSIONS

These studies establish that IL-13 signaling via the IL-13R alpha(2) is a key initiation point for a complex fibrotic program in the colon consisting of TGF-beta1 activation, IGF-I and Egr-1 expression, myofibroblast apoptosis, and myofibroblast production of collagen.

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.

Phase I, Pharmacokinetic and Pharmacodynamic Study of the Anti–Insulinlike Growth Factor Type 1 Receptor Monoclonal Antibody CP-751,871 in Patients With Multiple Myeloma

Purpose

A phase I first-in-human study was conducted to characterize the safety, tolerability, pharmacokinetic, and pharmacodynamic properties of the anti–insulinlike growth factor 1 receptor (IGF-IR) monoclonal antibody CP-751,871.

Patients and Methods

After informed consent and screening, 47 patients with multiple myeloma in relapse or refractory phase were enrolled into 11 dose-escalation cohorts of CP-751,871 at doses from 0.025 to 20 mg/kg for 4 weeks. Patients with less than a partial response to CP-751,871 treatment were eligible to receive CP-751,871 in combination with oral dexamethasone at the discretion of the investigator. Treatment with CP-751,871 and rapamycin with or without dexamethasone was also offered to patients enrolled in the 10 and 20 mg/kg cohorts with less than a partial response to initial therapy with single-agent CP-751,871.

Results

No CP-751,871-related dose-limiting toxicities were identified. Plasma CP-751,871 concentrations increased with dose and concentration-time profiles were consistent with those of antibodies with target-mediated disposition. Importantly, CP-751,871 administration led to a decrease in granulocyte IGF-IR expression and serum insulinlike growth factor 1 accumulation at high doses, suggesting systemic IGF-IR inhibition. Tumor response was assessed according to the European Group for Blood and Marrow Transplantation criteria. Nine responses were reported in 27 patients treated with CP-751,871 in combination with dexamethasone. Of interest, two of the patients with a partial response were progressing from dexamethasone treatment at study entry.

Conclusion

These data indicate that CP-751,871 is well tolerated and may constitute a novel agent in the treatment of multiple myeloma.

Elevated insulin-like growth factor 1 receptor, hepatocyte growth factor receptor and telomerase protein expression in mild ulcerative colitis

OBJECTIVE

The risk of development of colorectal carcinoma is elevated in chronic, long-standing ulcerative colitis (UC). The changes in regenerative and immortalizing pathways caused by the inflammatory process, and that have been proved to be carcinogenic in other human tissues, have not been fully and uniformly described. We assayed the expression alterations of regenerative signal receptors and cell-aging inhibitory systems within colonic crypts by considering the histological activity of the disease.

METHODS

I-type insulin-like growth factor receptor (IGF1R), hepatocyte growth factor receptor (HGFR), telomerase reverse transcriptase (TERT) and telomerase associated protein (TP-1) expression were evaluated immunohistochemically on biopsy specimens from 11 mild, 11 moderate and 12 severe active inflammation of UC cases and from 10 normal colonic tissue cases. Independent colonic biopsies from 5 healthy and 7 severe UC cases were used for TaqMan real-time RT-PCR validation.

RESULTS

In mild inflammation, all observed parameters showed significantly elevated epithelial protein expression (IGF1R: 22.3 +/- 9.46%; HGFR: 35.3 +/- 22.8%; TERT/TP-1: 2.1 +/- 1.87%/2 +/- 1.32%) compared to normal (p < 0.005). In moderately active inflammation, only IGF1R expression was significantly higher (50.2 +/- 8.6%) compared to normal and mild inflammation (p < 0.005). In severe inflammation, all parameters showed decreased epithelial expression; IGF1R showed decreased mRNA expression, while HGFR was overexpressed and TERT showed a decreased tendency.

CONCLUSIONS

The epithelial expression of IGF1R, HGFR and TERT/TP-1 is elevated in mildly active UC. This phenomenon may allow the epithelial cells that collected genetic defects during severe inflammatory episodes pathologically to survive and proliferate.

[Fibrogenesis and inflammatory bowel disease]

A substantial proportion of patients with Crohn's disease develops intestinal stenosis due to anomalous fiber deposits. These patients frequently require resection of the affected segment. Despite its evident clinical significance, intestinal fibrogenesis has received little attention in comparison with research into hepatic, pulmonary, renal or cutaneous fibrosis. There seems to be a certain genetic predisposition to developing intestinal fibrosis. A meta-analysis has demonstrated that the three main variants of the NOD2/CARD15 gene are associated with this complication. In Crohn's disease, a series of alterations in collagen synthesis, expression of various pro- and anti-fibrogenic factors and intestinal fibroblast function have been described in the last few years. More recently, the development of intestinal fibrosis has been attenuated in several experimental models. Nevertheless, further studies are required to improve our understanding of intestinal fibrogenesis and to develop effective strategies for its prevention and treatment.

Aberrant expression of the insulin-like growth factor-1 receptor by T cells from patients with Graves' disease may carry functional consequences for disease pathogenesis

Graves' disease (GD), an autoimmune process involving thyroid and orbital tissue, is associated with lymphocyte abnormalities including expansion of memory T cells. Insulin-like growth factor receptor-1 (IGF-1R)-bearing fibroblasts overpopulate connective tissues in GD. IGF-1R on fibroblasts, when ligated with IgGs from these patients, results in the expression of the T cell chemoattractants, IL-16 and RANTES. We now report that a disproportionately large fraction of peripheral blood T cells express IGF-1R (CD3+IGF-R+). CD3+IGF-1R+ T cells comprise 48 +/- 4% (mean +/- SE; n = 33) in patients with GD compared with 15 +/- 3% (n = 21; p < 10(-8)) in controls. This increased population of IGF-1R+ T cells results, at least in part, from an expansion of CD45RO+ T cells expressing the receptor. In contrast, the fraction of CD45RA+IGF-1R+ T cells is similar in GD and controls. T cells harvested from affected orbital tissues in GD reflect similar differences in the proportion of IGF-1R+CD3+ and IGF-1R+CD4+CD3+ cells as those found in the peripheral circulation. GD-derived peripheral T cells express durable, constitutive IGF-1R expression in culture and receptor levels are further up-regulated following CD3 complex activation. IGF-1 enhanced GD-derived T cell incorporation of BrdU (p < 0.02) and inhibited Fas-mediated apoptosis (p < 0.02). These findings suggest a potential role for IGF-1R displayed by lymphocytes in supporting the expansion of memory T cells in GD.