Endothelial MT1-MMP targeting limits intussusceptive angiogenesis and colitis via TSP1/nitric oxide axis.

Pathological angiogenesis contributes to cancer progression and chronic inflammatory diseases. In inflammatory bowel disease, the microvasculature expands by intussusceptive angiogenesis (IA), a poorly characterized mechanism involving increased blood flow and splitting of pre-existing capillaries. In this report, mice lacking the protease MT1-MMP in endothelial cells (MT1iΔEC ) presented limited IA in the capillary plexus of the colon mucosa assessed by 3D imaging during 1% DSS-induced colitis. This resulted in better tissue perfusion, preserved intestinal morphology, and milder disease activity index. Combined in vivo intravital microscopy and lentiviral rescue experiments with in vitro cell culture demonstrated that MT1-MMP activity in endothelial cells is required for vasodilation and IA, as well as for nitric oxide production via binding of the C-terminal fragment of MT1-MMP substrate thrombospondin-1 (TSP1) to CD47/αvß3 integrin. Moreover, TSP1 levels were significantly higher in serum from IBD patients and in vivo administration of an anti-MT1-MMP inhibitory antibody or a nonamer peptide spanning the αvß3 integrin binding site in TSP1 reduced IA during mouse colitis. Our results identify MT1-MMP as a new actor in inflammatory IA and a promising therapeutic target for inflammatory bowel disease.

Ratio of Circulating Estrogen Receptors Beta and Alpha (ERß/ERα) Indicates Endoscopic Activity in Patients with Crohn's Disease.

BACKGROUND: Data supporting a role of female hormones and/or their receptors in inflammatory bowel disease (IBD) are increasing, but most of them are derived from animal models. Estrogen receptors alpha (ERα) and beta (ERß) participate in immune and inflammatory response, among a variety of biological processes. Their effects are antagonistic, and the net action of estrogens may depend on their relative proportions. AIM: To determine the possible association between the balance of circulating ERß and ERα (ERß/ERα) and IBD risk and activity. METHODS: Serum samples from 145 patients with IBD (79 Crohn's disease [CD] and 66 ulcerative colitis [UC]) and 39 controls were retrospectively studied. Circulating ERα and ERß were measured by ELISA. Disease activities were assessed by clinical and endoscopic indices specific for CD and UC. RESULTS: Low values of ERß/ERα ratio were directly associated with clinical (p = 0.019) and endoscopic (p = 0.002) disease activity. Further analyses by type of IBD confirmed a strong association between low ERß/ERα ratio and CD clinical (p = 0.011) and endoscopic activity (p = 0.002). The receiver operating curve (ROC) analysis showed that an ERß/ERα ratio under 0.85 was a good marker of CD endoscopic activity (area under the curve [AUC]: 0.84; p = 0.002; sensitivity: 70%; specificity: 91%). ERß/ERα ratio was not useful to predict UC activity. CONCLUSIONS: An ERß/ERα ratio under 0.85 indicated CD endoscopic activity. The determination of serum ERß/ERα might be a useful noninvasive screening tool for CD endoscopic activity.

The effects of infliximab or adalimumab on vascular endothelial growth factor and angiopoietin 1 angiogenic factor levels in inflammatory bowel disease: serial observations in 37 patients.

BACKGROUND: Infliximab and adalimumab effectiveness might be related with changes in angiogenic factors. The aim of the study was to compare the concentrations of angiogenic proteins in patients with inflammatory bowel disease (IBD) and healthy controls and to analyze changes in the levels during infliximab and adalimumab treatment. METHODS: A prospective case-control study was conducted in 37 patients with IBD starting treatment with infliximab (16 with Crohn's disease and 6 with ulcerative colitis) or adalimumab (15 with Crohn's disease) and 40 control subjects. Four samples were taken from IBD patients, one before each of the first 3 doses of infliximab/adalimumab and one at week 14. Serum levels of vascular endothelial growth factor (VEGF), placental growth factor, angiopoietin 1 (Ang1), angiopoietin 2, and Tie2 were measured using enzyme-linked immunosorbent assay. RESULTS: Patients with IBD had higher VEGF levels than control subjects (511.5 ± 255.6 versus 395.5 ± 256.4; P = 0.05). Patients who achieved remission at the third dose of anti-TNF-alpha had lower VEGF levels at baseline (453.5 ± 250.7 versus 667.5 ± 153.9 pg/mL) and before the second (409.7 ± 217 versus 681.3 ± 350.6 pg/mL) and third (400.5 ± 222.8 versus 630.4 ± 243.1 pg/mL) doses compared with those with no remission (P < 0.05). Ang1 levels decreased before each treatment dose in patients who achieved remission (P < 0.05). High baseline VEGF levels predicted for a poor response to anti-TNF-alpha therapy (area under the receiver operating characteristics curve = 0.8), whereas high Ang1 levels were associated with disease remission (area under the receiver operating characteristics curve = 0.7). Concentrations of angiogenic proteins did not correlate with clinical activity scores. CONCLUSIONS: Circulating VEGF and Ang1 levels decrease after anti-TNF-alpha therapy and may predict response to treatment. Whether these changes are a direct effect of anti-TNF-alpha therapy or a sign of disease improvement remains to be elucidated.

Angiopoietins in inflammation and their implication in the development of inflammatory bowel disease. A review.

BACKGROUND: Angiopoietins are essential angiogenic mediators. Since inflammatory bowel disease (IBD) involves inflammation, ulceration and regeneration of the intestinal mucosa, the angiopoietin system has been proposed as a factor to maintain pathological angiogenesis during the development of the IBD. AIM: To review the potential role of angiopoietins in the inflammation driven by angiogenesis during the course of the IBD. METHODS: Publications were identified by PubMed searches using the following key words: angiopoietin; Tie-2 receptor; angiogenesis; inflammatory bowel disease and inflammation, in various combinations. RESULTS: Angiopoietin-1 acts as a regulator of blood vessel maturation and has anti-inflammatory properties, whereas angiopoietin-2 marks the onset of angiogenesis and is required for normal formation of lymph vessels. Both angiopoietins make use of their angiogenic regulatory effects via the angiopoietin tyrosine-kinase receptor (Tie-2). While angiogenesis has been shown to promote and sustain many events of inflammation, the involvement of the angiopoietin system in IBD has been reported in few studies. It is not clear whether the angiopoietins' role in the development of intestinal inflammation is due to an imbalance in the levels of these proteins or this system exerts its pro-angiogenic properties through a different mechanism during the close-loop relationship between angiogenesis and inflammation. CONCLUSIONS: Angiopoietins have key functions in the angiogenic process, and their abnormal activation might depend on their surrounding inflamed environment. The determination of these angiogenic factors in serum and tissue could be useful for monitoring IBD progression.

Relationship between levels of angiogenic and lymphangiogenic factors and the endoscopic, histological and clinical activity, and acute-phase reactants in patients with inflammatory bowel disease.

BACKGROUND: Angiogenic and lymphangiogenic factors (ALFs) may play an important role in inflammatory bowel disease (IBD). Our aims were to evaluate levels of ALFs in serum and the colonic mucosa culture supernatant (MCS) of patients with active and quiescent IBD and healthy subjects and to correlate them with the endoscopic, clinical and histological activity and with acute-phase reactants. METHODS: This is a prospective study of 28 controls and 72 IBD patients. Serum and MCS concentration of VEGFA, VEGFC, VEGFD, VEGFR1, VEGFR2, VEGFR3, PlGF, Ang1, Ang2 and Tie2 were measured by ELISA. Activity was established by specific indexes (CDAI, Mayo score, SES-CD, D'Haens scale and Riley index). Acute-phase reactants were routinely measured. RESULTS: MCS levels of all ALFs except VEGFR3 were higher in patients with endoscopic (p<0.05), clinical (p<0.05) and histological (p<0.01) activity than in those without it. In serum, VEGFA, VEGFC and Ang1 and VEGFA and Ang1 levels were lower in patients in remission than in patients with clinical and histological activity, respectively (p<0.05). There was a correlation between serum and MCS concentrations for VEGFD, VEGFR3, PlGF and Tie2 (r=0.25, r=0.48, r=-0.45 and r=0.36; p<0.05). Ang2 in MCS was the best predictor for the diagnosis of endoscopic, histological and clinical activity (area under ROC curve>0.8). CONCLUSIONS: MCS determination suggests a local increase in ALFs that correlates with IBD activity. Although the correlation between ALFs in serum and MCS was not good, the study of some of these factors as possible targets of new drugs for IBD constitutes a key new line of research.

Role of growth factors in the development of lymphangiogenesis driven by inflammatory bowel disease: a review.

Studies on angiogenesis and lymphangiogenesis have gained special relevance in research into factors potentially influencing the pathogenesis and course of inflammatory bowel disease (IBD). The results of the few existing studies on the distribution and density of lymphatic vessels and blood vessels in the context of IBD are controversial. Studies using the specific lymphatic marker podoplanin have revealed a significantly large number of lymphatic vessels in the colonic mucosa of patients with ulcerative colitis and Crohn's disease (compared to patients with normal mucosa), whereas other authors have found no significant differences. However, the role of vascular endothelial growth factor (VEGF) tyrosine-kinase receptor 3 (VEGFR-3) in the onset of IBD has not been analyzed. In recent years new biochemical, molecular, and immunohistochemical studies indicate that several families of growth factors, such as the VEGF family and their receptors, fibroblast growth factor-2, platelet-derived growth factor-BB, hepatocyte growth factor, the angiopoietin system, and integrins may play an important role in the onset of IBD. To date, no comparative studies have analyzed these growth factors and specific lymphatic markers. We examine how growth factors are involved in the development of pathological lymphangiogenesis in patients with IBD and determine whether they play a crucial role in disease exacerbation.

Soluble angiogenic factors in patients with acute pancreatitis.

BACKGROUND: Angiogenic factors are involved in the physiopathology of several inflammatory diseases and they probably play a role in the pathogenesis of acute pancreatitis (AP). AIMS: To investigate if angiogenic factors are elevated in patients with AP, their relationship with severity and clinical evolution of AP, and their use as prognosis markers of AP. METHODS: A case (25)-control (30) study was carried out. Patients with AP were classified according to severity (using Ranson and Glasgow scores) and according to their clinical evolution (taking into account the development of complications during hospital stay). Platelet-derived growth factor (PDGFBB), angiopoietin-1, angiopoietin-2 (Ang-2), angiopoietin tyrosine-kinase receptor, hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF), VEGF tyrosine-kinase receptor 1, and VEGF tyrosine-kinase receptor 2 were determined at 12 hours and then at 5 days after hospitalization. RESULTS: PDGFBB, Ang-2, angiopoietin tyrosine-kinase receptor, and HGF were significantly higher in cases (P<0.001), and in patients with unfavorable clinical evolution (P<0.001). PDGFBB and HGF were significantly higher in patients with severe AP (P<0.05). To predict unfavorable clinical evolution, PDGFBB, Ang-2, and HGF showed an area under receiver operating characteristic curve of 0.97. CONCLUSIONS: PDGFBB and HGF are related to severity of AP. These factors along with Ang-2 are related to clinical evolution and are useful in predicting the development of several complications during hospital stay. Therefore, these angiogenic factors could be useful as prognosis markers of AP.

Corticosteroids modulate angiogenic soluble factors in ulcerative colitis patients.

AIMS: The aim of this study was to compare angiogenic factors in serum levels of active ulcerative colitis (UC) patients and in healthy controls, and to analyze these angiogenic levels depending on the achievement of remission after oral corticosteroid treatment throughout treatment, and according to the Truelove-Witts activity index. METHODS: Blood samples were collected from 13 patients receiving oral corticosteroids for treatment of UC flares at three different intervals--baseline, during, and after treatment--and from 26 healthy controls. Vascular endothelial growth factor (VEGF), placental growth factor (PlGF), VEGF receptor 1 (VEGFR1), angiopoietins (Ang) 1 and 2, and its receptor Tie2 were assayed by ELISA. RESULTS: While VEGF and Ang2 levels in UC patients were higher than in healthy controls (P < 0.05), UC patients showed lower levels of Ang1 than healthy individuals (P < 0.05). In UC patients who achieved clinical remission after corticosteroid treatment, a statistically significant higher baseline serum level of PlGF was observed (22 ± 5 vs. 18 ± 2; P < 0.05). Angiogenic factor levels varied during treatment; however, they did not show a statistically significant correlation to the activity of the disease. CONCLUSIONS: VEGF, Ang1, and Ang2 levels showed statistically significant differences between UC patients and healthy controls. Although determination of PlGF serum levels before corticosteroid treatment might be helpful to anticipate the response by UC patients, no angiogenic pattern that could accurately predict "a priori" this response to corticosteroid treatment was observed. Corticosteroids altered temporarily circulating levels of VEGF, angiopoietins and Tie2. No correlation was found between systemic levels of angiogenic factors and the clinical activity of UC.

Outcomes of pregnancies fathered by inflammatory bowel disease patients exposed to thiopurines.

OBJECTIVES: Immunomodulators are used as maintenance treatment of inflammatory bowel disease (IBD). Data regarding their possible effects in the course of pregnancy when the father is exposed at the time of conception are limited. METHODS: To evaluate the outcomes of pregnancies of which the fathers were exposed to thiopurines at the time of conception. A series of male patients followed in seven IBD clinics in Madrid, Spain, was studied. Any exposure to thiopurines during the 3 months preceding conception was considered significant. Controls were pregnancies fathered by patients who either had never been treated with thiopurines or had interrupted them >3 months before conception. Statistical comparisons and multivariate analysis were carried out with the generalized estimating equations model. RESULTS: There were 46 conceptions in the exposed group (mercaptopurine 9, azathioprine 37) and 84 in the control group. In the exposed group, there were more Crohn's patients (82.6% vs. 53.6%), the duration of the disease was longer (median: 8 vs. 5 years), fathers were slightly older (mean: 34.2 vs. 32.7 years), and there were fewer patients on mesalamine (15.2% vs. 47.6%). Otherwise, baseline characteristics were similar in both groups. There were no significant differences regarding unsuccessful pregnancies-namely, spontaneous abortions, ectopic pregnancies, anembryonic pregnancies, or fetal deaths (10.9% exposed group vs. 13.1% control group; odds ratio (OR): 0.79, confidence interval (CI): 0.22-2.85), preterm births (4.3% vs. 2.4%; OR: 1.3, CI: 0.22-7.61), low birth weight (6.5% vs. 6%; OR: 1.06, CI: 0.25-4.54), or congenital malformations (2.2% vs. 2.4%; OR: 0.82, CI: 0.08-9). No infant neoplasms were detected. The proportion of conceptions that needed >1 year to be achieved was higher in the exposed group, but this was not statistically significant (15.2% vs. 8.3%; OR: 1.92, CI: 0.54-6.88). Multivariate analysis was carried out for unsuccessful pregnancies and fertility impairment, and it showed that, although mesalamine exposure confounded the effect of the exposure to thiopurines on these outcomes, this effect was still nonsignificant (respectively, OR: 0.49, CI: 0.17-1.44; OR: 2.82, CI: 0.7-11.38). CONCLUSIONS: Our data do not support the practice of routinely recommending to male patients that they interrupt thiopurines when wanting to conceive.