[Current position on Vedolizumab for ulcerative colitis and Crohn's disease]. / Vedolizumab bei Colitis ulcerosa und Morbus Crohn: eine Standortbestimmung.

Vedolizumab, the first drug in the class of anti-integrin molecules, is newly approved for ulcerative colitis and Crohn's disease and can be prescribed in Germany since mid-2014. By a specific receptor binding a relatively gut-selective mode of action was achieved without the known side effects of the systemic immunosuppression of the anti-TNF-alpha antibodies. According to the present data the safety profile of Vedolizumab appears to be more favorable than that of the anti-TNF- alpha therapy. Vedolizumab is suitable for induction therapy in patients with ulcerative colitis and Crohn's disease, however the kinetic of response compared with the anti-TNF-alpha antibodies seems to be slower. For maintenance therapy the Vedolizumab data show a deep and sustained remission in patients initially responding to induction therapy with a lower loss of efficacy in the long-term treatment known from the anti-TNF-alpha therapy. On the basis of currently available data the efficacy of Vedolizumab in ulcerative colitis appears to be slightly better than in Crohn's disease.

[Rational and efficient diagnosis in different stages of Crohn's disease]. / Rationale und rationelle Diagnostik in unterschiedlichen Krankheitsphasen des Morbus Crohn.

The treatment of patients with inflammatory bowel disease has become more complex in recent years through the introduction of various immunosuppressive agents as well as the approval of monoclonal antibodies. Patients receiving such treatment must be carefully monitored. National and international guidelines define a diagnostic and therapeutic context for the practitioner, but can only partially respond to specific questions on the procedure for individual patients. Within the framework of a project initiated by Abbott entitled "IBD ahead" 34 German IBD experts have elaborated concrete proposals for the utility of clinical symptom assessment, endoscopy and the use of laboratory parameters including foecal markers of inflammation. Furthermore, we discuss the significance of conventional X-rays, computed tomography, ultrasound and magnetic resonance tomography. These recommendations are illustrated by case studies from everyday practice in the participating centres.

[Are there gender-related differences in the therapeutic management of patients suffering from inflammatory bowel disease? Subgroup analysis of a prospective multicentre online-based trial]. / Gibt es geschlechtsspezifische Behandlungsunterschiede bei Patienten mit chronisch entzündlichen Darmerkrankungen? Eine Subgruppenanalyse einer prospektiven, multizentrischen, online-basierten Studie.

INTRODUCTION: The most frequently prescribed medications for patients suffering from inflammatory bowel disease (IBD) in the Rhein-Main region of Germany are aminosalicylates and corticosteroids irrespective of the disease activity. In contrast, immunomodulators only play a marginal role. As anti-TNF therapy is very costly, it is prescribed in outpatient services of hospitals rather than in gastroenterological practices. AIM: The aim of this study was to evaluate possible gender-related differences in the therapeutic management of IBD patients treated in the Rhein-Main region of Germany. METHODS: Data records about past medical history, disease status, laboratory values and medical treatment of outpatients of 10 gastroenterological practices and 3 hospitals were collected from November 1st 2005 to July 31st 2007 and analysed with regard to gender-related differences in therapy and disease management. RESULTS: Overall, no statistically significant difference in gender-specific medical treatment could be observed in the study cohort. However, detailed analyses revealed, that 1. women suffering from IBD, who are treated in outpatient services of hospitals, are more often under immunosuppressants, irrespective of disease activity, 2. in gastroenterological practices less than 3 % of patients are prescribed any immunosuppressive therapy (vs. 17 % [men] und 42 % [women] in hospital outpatient services), and 3. anti-TNF therapy is applied more frequently in men as compared to women in hospital outpatient services in both remission and active disease. CONCLUSION: This study discloses the gender-specific differences in the therapeutic management of IBD patients in a congested urban area in Germany. Further studies are required to confirm the tendencies detected.

Mechanisms and modulation of intestinal epithelial repair.

The mucosal epithelium of the alimentary tract represents a crucial barrier to a broad spectrum of noxious and immunogenic substances within the intestinal lumen. An impairment of the integrity of the mucosal epithelial barrier is observed in the course of various intestinal disorders including inflammatory bowel diseases (IBD), celiac disease, intestinal infections, and various other diseases. Furthermore, even under physiologic conditions temporary damage of the epithelial surface mucosa may be caused by proteases, residential flora, dietary compounds, or other factors. Generally, the integrity of the intestinal mucosal surface barrier is rapidly reestablished even after extensive destruction because of an enormous regenerative capability of the mucosal surface epithelium. Rapid resealing of the surface epithelium is accomplished by epithelial cell migration, also termed epithelial restitution, epithelial cell proliferation, and differentiation. Healing of the intestinal surface epithelium is regulated by a complex network of highly divergent factors, among them a broad spectrum of structurally distinct regulatory peptides that have been identified within the mucosa of the intestinal tract. These regulatory peptides, conventionally designated as growth factors and cytokines, play an essential role in regulating differential epithelial cell functions to preserve normal homeostasis and integrity of the intestinal mucosa. In addition, a number of other peptide molecules such as extracellular matrix factors and blood clotting factors, and also nonpeptide molecules including phospholipids, shortchain fatty acids, adenine nucleotides, trace elements, and pharmacological agents, have been demonstrated to modulate intestinal epithelial repair mechanisms. Some of these molecules may be released by platelets, adjacent stromal cells, inflammatory cells, or injured epithelial and nonepithelial cells and may play an important role in the modulation of intestinal injury. Repeated damage and injury of the intestinal surface are key features of various intestinal disorders including IBD and require constant repair of the epithelium. Enhancement of intestinal repair mechanisms by regulatory peptides or other modulatory factors may provide future approaches for the treatment of diseases that are characterized by injuries of the epithelial surface.

Reduced bone mineral density and unbalanced bone metabolism in patients with inflammatory bowel disease.

Patients with chronic inflammatory bowel diseases (IBD) are at increased risk to develop osteopenia and osteoporosis. New parameters for the assessment of bone formation and especially bone resorption have significantly improved the diagnostic procedures to characterize bone metabolism. Biochemical characterization of bone turnover in IBD patients may provide important information about the pathogenesis of osteoporosis in this patient population. A cross-sectional study was performed. One hundred forty-nine patients (77 men, 52 premenopausal, and 20 postmenopausal women) with IBD (104 with Crohn's disease [CD] and 45 with ulcerative colitis [UC]) underwent clinical, osteodensitometric, and metabolic bone assessment. Bone mineral density was determined by dual energy X-ray absorptiometry. Bone formation (bone alkaline phosphatase), bone resorption (N-terminal telopeptide of type-I collagen, free desoxypyridinoline, total pyridinoline, and desoxypyridinoline), vitamin D, and parathyroid hormone were assessed. Thirty-six percent of patients with CD and 32% with UC showed osteopenia, 15% with CD and 7% with UC showed osteoporosis. Bone resorption was significantly increased in IBD patients compared to normal controls, whereas bone formation did not show a compensatory increase. Bone formation was even more suppressed in the subset of patients currently treated with corticosteroids. Our data confirm the high prevalence of osteopenia and osteoporosis reported in IBD patients. Furthermore, we provide evidence for an increased bone resorption accompanied by low bone formation in IBD patients. This imbalance of bone metabolism is likely to be one of the reasons for increased bone loss in IBD patients.

Clinical relevance of transabdominal ultrasonography and magnetic resonance imaging in patients with inflammatory bowel disease of the terminal ileum and large bowel.

BACKGROUND: Ileocolonoscopy represents the diagnostic standard in the work-up of patients with inflammatory bowel diseases (IBD). Patients are often reluctant to be colonoscoped because of the invasiveness and pain sensation during colonoscopy. AIMS: To compare the usefulness oftransabdominal ultrasound (US) and magnetic resonance imaging (MRI) in assessing disease extension and activity in patients with IBD restricted to the terminal ileum and large bowel. PATIENTS AND METHODS: 61 patients with IBD [37 Crohn's disease (CD) and 24 ulcerative colitis (UC)] were prospectively studied. All patients underwent clinical and laboratory assessment, ileocolonoscopy, transabdominal sonography, and MRI within 5 days. Involved bowel segments were defined as those with bowel wall thickness >3 mm and increased Doppler signal on US or contrast enhancement of the bowel wall on MRI. To compare disease activity endoscopic, MRI and US findings were graded with newly developed scores. RESULTS: The segment-by-segment analysis revealed an overall accuracy of 89% for US and 73% for MRI in identifying active IBD. The accuracy was better in patients with UC than in patients with CD for both US and MRI. The endoscopic activity index (EAI) correlated stronger with the US activity index (r = 0.884) than with the MRI activity index (r = 0.344). The correlation of US and MRI activity indices with EAI was better in patients with UC compared with patients with CD. All three imaging methods showed a significant correlation with clinical disease activity in patients with UC but not in patients with CD. CONCLUSION: This study provides strong evidence that US should be considered as a first-choice method for follow-up of patients with IBD of the terminal ileum and large bowel.

Review article: the aetiopathogenesis of inflammatory bowel disease--immunology and repair mechanisms.

Although the aetiopathogenesis of Crohn's disease and ulcerative colitis, remains unsolved, current evidence indicates that defective T-cell apoptosis and impairment of intestinal epithelial barrier function play important roles in the pathogenesis of both conditions. Without appropriate control of T-cell proliferation and death during an immune response, an inappropriate accumulation of T cells and subsequent intestinal inflammation may occur. Differences in T-cell responses between Crohn's disease and ulcerative colitis have been identified, with mucosal T-cell apoptosis being defective in Crohn's disease, but not in ulcerative colitis. Furthermore, cell cycling is considerably faster, with a vigorous clonal expansion, in Crohn's disease, whereas, in ulcerative colitis, T cells cycle normally, but have a remarkably reduced capacity to divide and expand. The elimination of excessive T cells therefore seems to be a reasonable approach to restore the gut to a physiological state or, at least, a controlled state of inflammation. The tumour necrosis factor-alpha blocker, infliximab, exerts its beneficial effects, at least in part, by the induction of apoptosis in lamina propria T cells and monocytes. In addition, repeated damage and injury of the intestinal surface is a hallmark of inflammatory bowel disease and may facilitate the entry of luminal antigens into the mammalian organism and the initiation and perpetuation of both nonspecific and specific immune responses. A better understanding of and enhancement of intestinal repair mechanisms may thus provide future approaches for the treatment of inflammatory bowel disease.

Rescue therapy with tacrolimus is effective in patients with severe and refractory inflammatory bowel disease.

BACKGROUND: Oral tacrolimus, approved for the prophylaxis of organ rejection in liver or kidney transplants, has been reported to be effective in anecdotal cases of refractory inflammatory bowel disease. AIM: To evaluate the usefulness of low-dose oral tacrolimus in refractory inflammatory bowel disease. METHODS: Thirty-one adult Caucasian patients with steroid-dependent (n = 15) or steroid-refractory (n = 16) inflammatory bowel disease (Crohn's disease, n = 6; ulcerative colitis, n = 23; pouchitis, n = 2) were enrolled. Tacrolimus (0.1 mg/kg body weight per day) was administered orally in 30 patients and initially intravenously in one patient (0.01 mg/kg body weight per day), aiming for serum trough levels of 4-6 ng/mL. The median treatment duration was 12 months (range, 1-137 months). RESULTS: Twenty-eight patients (90.3%) experienced a clinical and laboratory response and 20 (64.5%) went into remission. One ulcerative colitis patient and two Crohn's disease patients did not improve. Three ulcerative colitis patients (9.7%) were colectomized at 1, 12 and 24 months after tacrolimus initiation. In 19 of 23 patients (82.6%) taking steroids, steroids were reduced or discontinued. Side-effects included a temporary rise of creatinine (n = 3, 9.7%), tremor or paraesthesias (n = 3, 9.7%), hyperkalaemia (n = 1, 3.2%), hypertension (n = 1, 3.2%) and an opportunistic infection (n = 1, 3.2%). CONCLUSION: Oral tacrolimus is safe and effective in refractory inflammatory bowel disease.

Peptide growth factors in the intestine.

A continuously increasing number of regulatory peptides has been demonstrated to be expressed in the intestine and to modulate several functional properties of various intestinal cell populations, including the intestinal epithelium and lamina propria cell populations. These regulatory peptides include members of the epidermal growth factor (EGF) family, the transforming growth factor beta (TGF-beta) family, the insulin-like growth factor (IGF) family, the fibroblast growth factor (FGF) family, the trefoil factor (TFF) family, the colony-stimulating factor (CSF) family, and a few other seemingly unrelated regulatory peptides, such as hepatocyte growth factor (HGF), platelet-derived growth factor (PDGF), and various interleukins, interferons and tumour necrosis factor-related proteins. In addition to the well-known effects on cell proliferation, these regulatory peptide factors regulate several other functional properties of epithelial and other cell populations, such as differentiation, migration, and extracellular matrix deposition and degradation. This review is designed not to discuss all the identified factors in detail but to highlight some of the basic principles of growth factor action in the intestine. It focuses mainly on classical growth factors rather than interleukins and interferons.

Transforming growth factor-beta and hepatocyte growth factor plasma levels in patients with inflammatory bowel disease.

OBJECTIVE: An increased mucosal expression of transforming growth factor-beta (TGF-beta) and hepatocyte growth factor (HGF) has been reported in patients with active inflammatory bowel diseases (IBD) and in proximity to injured gastric and intestinal mucosal surfaces. The aim of this study was to measure systemic concentrations of TGF-beta and HGF and to assess their potential value to predict disease activity or severity of inflammation in patients with inflammatory bowel diseases. DESIGN AND METHODS: Plasma HGF and TGF-beta1 peptide levels were determined in 29 patients with ulcerative colitis, 45 patients with Crohn's disease and 28 healthy controls using commercial ELISA assays. Peptide levels were correlated with disease activity indices and various laboratory parameters. RESULTS: HGF and TGF-beta1 plasma levels were detected in all control and IBD subjects. Although a tendency towards increased HGF and TGF-beta1 peptide levels in IBD patients was observed, differences between groups were not significant In ulcerative colitis patients HGF plasma levels positively correlated with white blood cell counts and negatively correlated with serum albumin concentrations and haematocrit. In Crohn's disease patients, a positive correlation between TGF-beta and platelet count was observed. CONCLUSIONS: HGF and TGF-beta1 plasma concentrations are not significantly different in IBD and healthy control subjects. Stratification of IBD patients according to disease activity did not reveal any substantial differences, suggesting that HGF and TGF-beta plasma levels have no value in the assessment of disease activity or severity of inflammation in patients with IBD.

Epithelial cell-derived components induce transforming growth factor-alpha mRNA expression and epithelial cell proliferation in vitro.

BACKGROUND: Epidermal growth factor (EGF) and transforming growth factor (TGF)-alpha protect the gastrointestinal mucosa against injury. In response to mucosal injury TGF-alpha, but not EGF, is locally increasingly expressed in the mucosa of the rat colon and stomach 4-8 h after injury. The aim of our present study was to characterize the possible signal for the induction of TGF-alpha expression. METHODS: Monolayers of the non-transformed intestinal epithelial cell (IEC)-6 and IEC-18 lines were harvested, homogenized and shock-frozen at -80 degrees C for 1 h. Cell cultures of intact IEC-6 or IEC-18 cells were exposed to these cell homogenates and modulation of epithelial cell migration and proliferation was evaluated using standardized procedures as described previously. TGF-alpha mRNA expression in the exposed epithelial cell monolayers was assessed using reverse transcriptase-polymerase chain reaction (RT-PCR) and normalized to the expression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). RESULTS: The proliferation of IEC-6 and IEC-18 epithelial cell monolayers was significantly inhibited if epithelial cell homogenates of 2000 cells/ml or more, and significantly induced if homogenates of less than 2000 cells/ml, were applied to the medium of the monolayers in vitro. In proliferating epithelial cells, a significant two-fold increase in TGF-alpha mRNA expression was obtained at 48 h and 72 h after application of the cell homogenates. The homogenate-induced epithelial cell proliferation was completely abolished after preincubation of the epithelial cell homogenates with neutralizing monoclonal anti-TGF-alpha antibodies. No effect on epithelial cell migration was noticed after application of epithelial-cell homogenates to the cell cultures. CONCLUSIONS: Epithelial cell-derived components induce TGF-alpha mRNA expression and TGF-alpha-dependent cell proliferation of intact epithelial cells. We hypothesize that epithelial cell interaction bears one of the possible signals for the increased TGF-alpha mRNA expression after mucosal injury.

Clinical trial: five or ten cycles of granulocyte-monocyte apheresis show equivalent efficacy and safety in ulcerative colitis.

BACKGROUND: Ulcerative colitis is characterized by leucocyte infiltration into the colonic mucosa. Granulocyte-monocyte apheresis depletes these cells. AIM: To assess the non-inferiority of 5-10 apheresis treatments in patients with steroid-dependent or steroid-refractory ulcerative colitis. METHODS: A total of 196 adults with moderate-severe ulcerative colitis were randomized 1:1 to 5 (n = 96) or 10 (n = 90) open label apheresis treatments. The primary endpoint was non-inferiority of clinical activity index score after 12 weeks. RESULTS: The intent-to-treat population comprised 82 and 80 patients for the 5- and 10-treatment groups, respectively. The difference between the two groups in mean clinical activity index was 0.24 with an upper 95% confidence interval of 1.17, which was below a predefined non-inferiority threshold of 1.33. Clinical activity index score improved from baseline in both groups (from 8.7 to 5.6 with 5 treatments, and from 8.8 to 5.4 with 10), with no significant difference between the groups (P = 0.200). Outcomes for the 5- and 10-treatment groups were similar--clinical remission: 44% and 40%, respectively (P = 0.636); clinical response: 56% and 59%, respectively (P = 0.753). The treatment was well tolerated in both groups. CONCLUSIONS: This prospective study comparing apheresis regimens in ulcerative colitis demonstrates that 5 treatments were not inferior to 10 treatments in steroid-refractory or -dependent ulcerative colitis.

[Pathophysiological-based diagnosis and therapy of iron-deficient anaemia in inflammatory bowel disease]. / Pathophysiologisch-orientierte Diagnostik und Therapie der Eisenmangelanämie bei chronisch entzündlichen Darmerkrankungen.

Anaemia is the most frequent extraenteric complication of inflammatory bowel disease (IBD, Crohn's disease and ulcerative colitis). A disabling complication of IBD, anaemia worsens the patient's general condition and quality of life, and increases hospitalization rates. The main types of anemia in IBD are iron deficiency anemia and anemia of chronic disease. The combination of the serum transferrin receptor with ferritin concentrations and inflammatory markers allows a reliable assessment of the iron status. Iron deficiency is usually treated with oral iron supplements. However, it is less effective in IBD and may lead to an increased inflammatory activity through the generation of reactive oxygen species. A systematic review of anemia in IBD, its pathogenetic features, epidemiology, diagnosis and therapy based on the evidence from recent studies will be the focus of this article.

Escherichia coli strain Nissle 1917 ameliorates experimental colitis via toll-like receptor 2- and toll-like receptor 4-dependent pathways.

Toll-like receptors (TLRs) are key components of the innate immune system that trigger antimicrobial host defense responses. The aim of the present study was to analyze the effects of probiotic Escherichia coli Nissle strain 1917 in experimental colitis induced in TLR-2 and TLR-4 knockout mice. Colitis was induced in wild-type (wt), TLR-2 knockout, and TLR-4 knockout mice via administration of 5% dextran sodium sulfate (DSS). Mice were treated with either 0.9% NaCl or 10(7) E. coli Nissle 1917 twice daily, followed by the determination of disease activity, mucosal damage, and cytokine secretion. wt and TLR-2 knockout mice exposed to DSS developed acute colitis, whereas TLR-4 knockout mice developed significantly less inflammation. In wt mice, but not TLR-2 or TLR-4 knockout mice, E. coli Nissle 1917 ameliorated colitis and decreased proinflammatory cytokine secretion. In TLR-2 knockout mice a selective reduction of gamma interferon secretion was observed after E. coli Nissle 1917 treatment. In TLR-4 knockout mice, cytokine secretion was almost undetectable and not modulated by E. coli Nissle 1917, indicating that TLR-4 knockout mice do not develop colitis similar to the wt mice. Coculture of E. coli Nissle 1917 and human T cells increased TLR-2 and TLR-4 protein expression in T cells and increased NF-kappaB activity via TLR-2 and TLR-4. In conclusion, our data provide evidence that E. coli Nissle 1917 ameliorates experimental induced colitis in mice via TLR-2- and TLR-4-dependent pathways.

Patients with active inflammatory bowel disease lack immature peripheral blood plasmacytoid and myeloid dendritic cells.

BACKGROUND: Breakdown of tolerance against the commensal microflora is believed to be a major factor in the pathogenesis of inflammatory bowel disease (IBD). Dendritic cells (DC) have been implicated in this process in various animal models, but data on human DC in IBD are very limited. AIM: To characterise plasmacytoid DC (PDC) and myeloid DC (MDC) in patients with active versus inactive IBD and healthy controls. PATIENTS AND METHODS: Peripheral blood was obtained from 106 patients (Crohn's disease (CD) n=49, ulcerative colitis (UC) n=57) and healthy controls (n=19). Disease activity was scored using the modified Truelove Witts (MTWSI) for UC and the Harvey Bradshaw severity indices (HBSI) for CD. Four colour flow cytometric analysis was used to identify, enumerate, and phenotype DC. DC from patients with acute flare ups and healthy controls were cultured and stimulated with CpG ODN 2006 or lipopolysaccharide (LPS). RESULTS: IBD patients in remission (PDC UC, 0.39%; CD, 0.35%; MDC-1 UC, 0.23%; CD, 0.22% of PBMC) have slightly lower numbers of circulating DC compared with healthy controls (PDC 0.41%, MDC-1 0.25% of PBMC). In acute flare ups IBD patients experience a significant drop of DC (PDC UC, 0.04%; CD, 0.11%; MDC-1 UC, 0.11%; CD, 0.14% of PBMC) that correlates with disease activity (correlation coefficients: PDC MTWSI, 0.93; HBSI, 0.79; MDC-1 MTWSI, 0.75; HBSI, 0.81). Moreover, both express alpha4beta7 integrin and display an immature phenotype. Freshly isolated PDC and MDC-1 from untreated flaring IBD patients express higher baseline levels of CD86 which increases further in culture and upon stimulation compared with healthy controls. CONCLUSION: IBD patients lack immature blood DC during flare ups which possibly migrate to the gut. An aberrant response to microbial surrogate stimuli suggests a disturbed interaction with commensals.

Cytokine modulation of intestinal epithelial cell restitution: central role of transforming growth factor beta.

BACKGROUND: After various forms of superficial injury, mucosal integrity is re-established by rapid migration of epithelial cells across the wound margins in a process termed restitution. The aim of the present study was to assess the role of several regulatory peptides produced within the intestinal mucosa in epithelial restitution. METHODS: The effects of various cytokines and peptide growth factors were studied in an in vitro model of intestinal epithelial restitution. Standard "wounds" were established in confluent monolayers of the intestinal cell line IEC-6, and migration was quantitated in the presence or absence of the physiologically relevant cytokines transforming growth factor (TGF)-alpha, epidermal growth factor (EGF), interleukin (IL)-1 beta, IL-6, tumor necrosis factor (TNF)-alpha, interferon gamma (IFN-gamma), and platelet-derived growth factor (PDGF). RESULTS: Four factors (TGF-alpha, EGF, IL-1 beta, and IFN-gamma) enhanced epithelial cell restitution by 2.3-fold to 5.5-fold. In contrast, IL-6, TNF-alpha, PDGF, and an endotoxin lipopolysaccharide had no effect on cell migration. Enhancement of restitution was independent of proliferation. The restitution-promoting cytokines TGF-alpha, EGF, IL-1 beta, and IFN-gamma increase the production of bioactive TGF-beta 1 peptide in wounded IEC-6 cell monolayer. The promotion of IEC-6 restitution by various cytokines could be completely blocked by addition of immunoneutralizing anti-TGF-beta 1. CONCLUSIONS: These findings suggest that various cytokines that are expressed in intestinal mucosa promote epithelial restitution after mucosal injury through increased production of bioactive TGF-beta 1 in epithelial cells.

Interleukin 2 modulates intestinal epithelial cell function in vitro.

Although interleukin 2 (IL-2) has been presumed to have a highly circumscribed range of target cells limited largely to classic immune cell populations, the presence of functional IL-2 receptors in rat epithelial cell lines has recently been demonstrated. Limited information is available about the functional effects of IL-2 on intestinal epithelial cells. The effect of recombinant IL-2 on intestinal epithelial cell migration was assessed using a previously described in vitro model of epithelial restitution by quantitation of cells migrating into standard wounds established in confluent IEC-6 cell monolayers. Transforming growth factor beta content was assessed by Northern blot and bioassay. Exogenous IL-2 enhanced epithelial cell restitution in vitro on average 3.8-fold; this effect was independent of cell proliferation. Enhancement of restitution through IL-2 could be completely blocked through antibodies directed against TGFbeta1 and interleukin-2 receptor, indicating that stimulation of epithelial cell restitution is specifically enhanced by interleukin-2 and mediated through a TGFbeta-dependent pathway. In addition, increased expression of TGFbeta1 mRNA and increased levels of bioactive TGFbeta peptide in wounded monolayers treated with IL-2 compared to unwounded monolayers cultured in serum-deprived medium alone support the notion that enhancement of epithelial cell restitution in vitro is mediated through a TGFbeta-dependent pathway. These studies suggest that IL-2, a potent cytokine whose biological origin and targets have been presumed to be largely limited to lymphocyte and macrophage populations, may play a role in preserving the integrity of the intestinal epithelium following various forms of injuries.

Hepatocyte growth factor/scatter factor modulates intestinal epithelial cell proliferation and migration.

Various peptide growth factors have been found to regulate epithelial cell function within the mucosal epithelium of the gastrointestinal tract. In this study hepatocyte growth factor/scatter factor (HGF/SF) was found to stimulate intestinal epithelial cell proliferation: 2.5-fold in the non-transformed rat small intestinal epithelial cell line IEC-6 and 1.9-fold in the human colon cancer-derived HT-29 cell line. In addition, HGF/SF enhanced epithelial cell restitution, the initial step involved in gastrointestinal wound healing, in an in vitro model. Migration of IEC-6 in wounded monolayers was enhanced up to 7-fold. Enhancement of restitution by HGF could be completely abrogated by addition of immunoneutralizing anti-TGF beta 1, indicating that this process is mediated through a TGF beta-dependent pathway. These findings suggest that HGF exerts functional effects on intestinal epithelial cell populations and may play a role in the morphogenesis of the gastrointestinal tract and its remodeling following injury.