Alberto Malesci

Inflammation and Coagulation in Inflammatory Bowel Disease: The Clot Thickens

Inflammation and coagulation play crucial roles in the pathogenesis of multiple chronic inflammatory disorders. Growing evidence highlights a tight mutual network in which inflammation, coagulation, and fibrinolysis play closely related roles. Crohns disease (CD) and ulcerative colitis (UC), the two major forms of inflammatory bowel disease (IBD), are chronic inflammatory conditions, characterized by a hypercoagulable state and prothrombotic conditions, and accompanied by abnormalities in coagulation. From a pathophysiological point of view, cells and molecules classically implicated in the physiological process of coagulation have now been shown to behave abnormally in IBD and possibly to also play an active role in disease pathogenesis and/or disease progression. This paper reviews studies performed on the coagulation profile and risk factors for thrombosis in IBD. In particular, an overview is provided of the epidemiology, clinical features, and etiology of thromboembolic complications in IBD. Furthermore, we review hemostatic abnormalities in IBD, as well as the cell types involved in such processes. Finally, we highlight the coagulation system as a dynamic participant in the multifaceted process of chronic intestinal inflammation. Overall, an overview is provided that the coagulation system represents an important, though previously underestimated, component of IBD pathogenesis, and may be a possible target for therapeutic intervention.

VEGF-A links angiogenesis and inflammation in inflammatory bowel disease pathogenesis.

BACKGROUND & AIMS Vascular endothelial growth factor A (VEGF-A) mediates angiogenesis and might also have a role in inflammation and immunity. We examined whether VEGF-A signaling has a role in inflammatory bowel disease (IBD). METHODS Expression levels of VEGF-A, and its receptors VEGFR-1 and VEGFR-2, were examined in samples from patients with IBD and compared with those of controls. The capacity of VEGF-A to induce angiogenesis was tested in human intestinal microvascular endothelial cells using cell-migration and matrigel tubule-formation assays. Levels of vascular cellular adhesion molecule-1 and intercellular adhesion molecule were measured by flow cytometry to determine induction of inflammation; neutrophil adhesion was also assayed. Expression patterns were determined in tissues from mice with dextran sulfate sodium (DSS)-induced colitis; the effects of VEGF-A overexpression and blockade were assessed in these mice by adenoviral transfer of VEGF-A and soluble VEGFR-1. Intestinal angiogenesis was measured by quantitative CD31 staining and leukocyte adhesion in vivo by intravital microscopy. RESULTS Levels of VEGF-A and VEGFR-2 increased in samples from patients with IBD and colitic mice. VEGF-A induced angiogenesis of human intestinal microvascular endothelial cells in vitro as well as an inflammatory phenotype and adherence of neutrophils to intestinal endothelium. Overexpression of VEGF-A in mice with DSS-induced colitis worsened their condition, whereas overexpression of soluble VEGFR-1 had the opposite effect. Furthermore, overexpression of VEGF-A increased mucosal angiogenesis and stimulated leukocyte adhesion in vivo. CONCLUSIONS VEGF-A appears to be a novel mediator of IBD by promoting intestinal angiogenesis and inflammation. Agents that block VEGF-A signaling might reduce intestinal inflammation in patients with IBD.

Reduced likelihood of metastases in patients with microsatellite-unstable colorectal cancer

Purpose: The outcome of patients with colorectal cancer is more favorable when the tumor exhibits high-frequency microsatellite instability (MSI). Although associated with earlier-stage tumors, MSI has been proposed as an independent predictor of survival. We tested the prognostic value of MSI in a large series of patients diagnosed with colorectal cancer in the last decade. Experimental Design: The survival of 893 consecutive patients with colorectal cancer characterized by microsatellite status was analyzed. The 89 (10%) patients with MSI cancer were classified according to tumor mismatch repair (MMR) defect, MMR germ-line mutation, hMLH1 and p16 promoter methylation, BRAF and K-ras mutations, and frameshifts of target genes. Results: The colorectal cancer–specific survival was significantly (P = 0.02) better in patients with MSI cancer than in those with stable tumor (MSS). MSI did not predict a significantly lower risk of cancer-related death if tumor stage was included in the multivariate analysis [hazard ratio, 0.72; 95% confidence interval (95% CI), 0.40-1.29; P = 0.27]. Instead, MSI was strongly associated with a decreased likelihood of lymph node (odds ratio, 0.31; 95% CI, 0.17-0.56; P < 0.001) and distant organ (odds ratio, 0.13; 95% CI, 0.05-0.33; P < 0.001) metastases at diagnosis, independently of tumor pathologic features. Molecular predictors of reduced metastatic risk, and then of more favorable prognosis, included TGFβRII mutation for all MSI tumors, hMSH2 deficiency for hereditary non-polyposis colorectal cancer, and absence of p16 methylation for sporadic hMLH1-deficient cancers. Conclusions: Tumor MSI is a stage-dependent predictor of survival in patients with colorectal cancer. The decreased likelihood of metastases in patients with MSI cancer is associated with specific genetic and epigenetic changes of the primary tumor.

Unique role of junctional adhesion molecule-a in maintaining mucosal homeostasis in inflammatory bowel disease.

BACKGROUND & AIMS Junctional adhesion molecule-A (JAM-A) is localized at the tight junctions and controls leukocyte migration into the tissues. However, its functional role in inflammatory bowel disease (IBD) is unexplored. METHODS Control, Crohns disease (CD), and ulcerative colitis (UC) tissue specimens were studied for JAM-A expression, as well as the colon of mice given dextran sodium sulfate (DSS). Wild-type and JAM-A(-/-), Tie-2-Cre-JAM-A(-/-) (endothelial/hematopoietic-specific JAM inactivation) mice were studied for susceptibility to DSS. Disease activity and colonic inflammation were assessed using a disease activity index histology and endoscopy, and mucosal cytokines were measured by enzyme-linked immunosorbent assay. JAM-A function was investigated by RNA silencing in epithelial cells, and apoptosis was measured. RESULTS In both CD and UC, as well as in experimental colitis, there is a loss of epithelial but not endothelial JAM-A expression. Deletion of JAM-A results in a dramatic increase in susceptibility to DSS colitis, as assessed by weight loss, disease activity index, histologic and endoscopic severity, and strikingly high mortality rates. This is not caused by the absence of JAM-A in the endothelial or hematopoietic compartments because Tie-2-Cre-JAM-A(-/-) mice are no more susceptible to DSS colitis than wild-type animals. JAM-A(-/-) mice displayed increased intestinal permeability and inflammatory cytokine production, and marked epithelial apoptosis. Silencing of JAM-A in intestinal epithelial cells resulted in increased permeability in vitro. CONCLUSIONS Our results show a nonredundant and novel role of JAM-A in controlling mucosal homeostasis by regulating the integrity and permeability of epithelial barrier function.

Prospective comparison of computed tomography enterography and magnetic resonance enterography for assessment of disease activity and complications in ileocolonic Crohn's disease

Background: Studies comparing magnetic resonance enterography (MRE) and computerized tomography enterography (CTE) for Crohns disease (CD) are scarce. Methods: The aim of this study was to prospectively compare the sensitivity, specificity, and accuracy of abdominal MRE and CTE to assess disease activity and complications (fistulas, strictures) in ileocolonic CD. A total of 44 patients (23 male; 21 female; mean age 44) with ileocolonic CD underwent both MR and CT in a short time interval (mean 5 days). A 16‐slice CT with intravenous contrast and an MRI with oral and paramagnetic intravenous contrast were performed. Ileocolonoscopy was used as the reference standard. Sensitivity values of CT and MR for detection of extraenteric signs of disease were compared with the McNemar test, with results of imaging studies, surgery, and physical examination as reference standards. Results: No significant differences in sensitivity, specificity, and accuracy were observed between MRE and CTE regarding the following parameters at the patient level: localization of CD (P = 1.0), bowel wall thickening (P = 1.0), bowel wall enhancement (P = 1.0), enteroenteric fistulas (P = 0.08), detection of abdominal nodes (P = 1.0), and perivisceral fat enhancement (P = 0.31). MR was significantly superior compared to CT in detecting strictures (P = 0.04). Per segment analysis showed that MRE was significantly superior to CTE in detecting ileal wall enhancement (P = 0.02). Conclusions: MR and CT are equally accurate to assess disease activity and bowel damage in CD. MR may be superior to CT in detecting intestinal strictures and ileal wall enhancement. MR may represent an alternative technique to CT in assessing ileocolonic CD. (Inflamm Bowel Dis 2010)

Partial regression of Barrett's esophagus by long-term therapy with high-dose omeprazole☆☆☆★

BACKGROUND Barretts esophagus is mainly regarded as an acquired condition related to increased gastroesophageal reflux. Thus it is conceivable that abolition of acid reflux would lead to its regression. The aim of this study was to assess whether long-term treatment with high-dose omeprazole (60 mg/day) produces a consistent control of gastric acid production and normalizes the esophageal acid exposure, thus reducing the length of Barretts epithelium. METHODS Fourteen patients (8 men and 6 women, mean age 52 years) with histologic diagnosis of columnar epithelium longer than 3 cm in the distal part of the esophagus were enrolled and began receiving 60 mg of omeprazole in a single daily morning dose. Before therapy and after 6 and 12 months of therapy, all patients had endoscopy with four-quadrant biopsies at 2 cm intervals. A 24-hour esophagogastric pH recording was performed at entry and after 10 days, 6 months, and 12 months of treatment in all patients. RESULTS The initial length of Barretts epithelium (4.5 +/- 1.9 cm) was significantly reduced after 6 months (3.1 +/- 1.1; p < 0.01) and 12 months (2.1 +/- 1.6; p < 0.005) of treatment. Values were significantly lower at 12 than at 6 months (p < 0.03). The 24-hour mean gastric pH after 10 days (5.89 +/- 0.58), 6 months (5.71 +/- 0.55), and 12 months (5.54 +/- 0.76) of therapy was always higher (p < 0.001) than the basal level (1.9 +/- 0.49). No significant difference in gastric pH was seen over the treatment period. The 24-hour mean percent of time in which pH in the esophagus was below 4.0 decreased significantly (p < 0.001) from a basal rate of 29.4% to 3.5%, 3.0%, and 4.9% in the various time intervals of therapy. There was a normalization of esophageal acid exposure in all patients but two. CONCLUSIONS It can be concluded that the antisecretory effect of 60 mg/day of omeprazole is consistent and is kept constant throughout the entire 1-year treatment period. The consequent normalization of esophageal acid exposure in almost all patients in our series led to a partial, but significant, regression in the length of Barretts epithelium.

Endoscopic submucosal dissection in patients with early esophageal squamous cell carcinoma: results from a prospective Western series

BACKGROUND Although endoscopic submucosal dissection (ESD) is becoming accepted as an established treatment for superficial esophageal squamous cell neoplasia, the majority of data on this endoscopic modality has been provided by Japanese series. OBJECTIVE To assess the efficacy and safety of ESD for esophageal squamous cell neoplasia in a consecutive series of patients treated in a Western setting. DESIGN AND SETTING Single-center, prospective observational study. PATIENTS AND INTERVENTION From January 2005 to July 2008, 20 patients with superficial esophageal squamous cell neoplasia were treated by ESD. MAIN OUTCOME MEASUREMENTS Rates of en bloc resection, complete resection, and complications were evaluated as short-term outcomes. Overall survival, local or distant recurrence, and postoperative stricture rates were evaluated as long-term outcomes. RESULTS ESD was performed in 20 patients (mean age 64 years, range 46-81 years; 16 men). The mean size of the lesion was 32 mm (range 15-60 mm); it was 30 mm or larger in 14 patients (70%). The mean time of ESD was 89 minutes (range 58-180 minutes). En bloc resection with resection-free margins was achieved in 18 patients (90%), whereas 2 patients presented with incomplete or indeterminate resection. Two cases (10%) of mediastinal emphysema without overt perforation and 1 case (5%) of post-ESD symptomatic stricture were reported. No local or distant post-ESD recurrence occurred in those with resection-free margins at a median follow-up of 18 months. LIMITATIONS Small number of patients and limited follow-up. CONCLUSION This Western series study confirms that ESD is a potentially curative treatment for superficial esophageal squamous cell neoplasia. Early and late complication rates were comparable to those of Japanese series. ESD should be probably considered as the treatment of choice in all large lesions amenable to endoscopic treatment.

The lymphatic system controls intestinal inflammation and inflammation-associated colon cancer through the chemokine decoy receptor D6

Background and aims Inflammatory CC chemokines have long been associated with cancer, but unequivocal evidence of a role in clinically relevant models of carcinogenesis is lacking. D6, a promiscuous decoy receptor that scavenges inflammatory CC chemokines, plays a non-redundant role in reducing the inflammatory response in various organs. As inflammation is a key player in the development of inflammatory bowel disease (IBD) and IBD-associated colorectal cancer, we investigated D6 expression in human colitis and colon cancer, and its role in experimental colitis and inflammation-associated colon cancer. Results In humans, D6 was mainly expressed by lymphatic vessels and leukocytes in the mucosa of individuals with IBD and colon cancer, as well as the mucosa of control individuals. Mice lacking expression of D6 were significantly more susceptible to experimental colitis than wild-type mice and failed to resolve colitis, with significantly higher levels of several pro-inflammatory chemokines. In bone marrow chimeric mice, the ability of D6 to regulate colitis was tracked to the stromal/lymphatic compartment, with no contribution of haemopoietic cells. Finally, after administration of the carcinogen azoxymethane, D6−/− mice showed increased susceptibility to colitis-associated cancer in the distal segment of the colon compared with wild-type mice. Conclusions D6 expressed on lymphatic vessels plays a key role in the control of intestinal inflammation and the development of inflammation-associated colon cancer. Our results reveal a new unexpected role for the lymphatic system in the pathogenesis of IBD and intestinal cancer, and candidate chemokines as novel players in tumour promotion and progression.

The Chemokine Receptor CX3CR1 Is Involved in the Neural Tropism and Malignant Behavior of Pancreatic Ductal Adenocarcinoma

Tumor perineural dissemination is a hallmark of human pancreatic ductal adenocarcinoma (PDAC) and represents a major source of local tumor recurrence after surgery. In this study, we provide in vitro and in vivo evidence that the chemokine receptor CX3CR1 may be involved in the neurotropism of PDAC cells to local peripheral nerves. Neoplastic cells from PDAC cell lines and surgical specimens express the chemokine receptor CX3CR1, absent in normal pancreatic ducts. Its unique ligand, the transmembrane chemokine CX3CL1, is expressed by neurons and nerve fibers. CX3CR1 + PDAC cell lines migrated in response to human recombinant CX3CL1 and specifically adhered to CX3CL1-expressing cells of neural origin via mechanisms involving activation of G proteins, beta1 integrins, and focal adhesion kinase. In vivo experiments with transplanted PDAC showed that only CX3CR1-transfected tumor cells infiltrated the local peripheral nerves. Immunohistochemistry of CX3CR1 in PDAC specimens revealed that 90% of the samples were positive with a heterogeneous pattern of expression. High receptor score was significantly associated with more prominent tumor perineural infiltration evaluated histologically (P = 0.026). Regression analyses (univariate and multivariate) showed that high CX3CR1 expression and perineural invasion were strongly associated with local and earlier tumor recurrence (P = 0.007). Collectively, this study shows that the CX3CR1 receptor may be involved in PDAC tumor neurotropism and is a relevant and independent risk factor to predict an early local tumor relapse in resected patients. Thus, the CX3CR1-CX3CL1 axis could represent a valuable therapeutic target to prevent tumor perineural dissemination in pancreatic cancer.

The added value of impedance-pH monitoring to Rome III criteria in distinguishing functional heartburn from non-erosive reflux disease

INTRODUCTION Functional heartburn is defined by Rome III criteria as an endoscopy-negative condition with normal oesophageal acid exposure time, negative symptom association to acid reflux and unsatisfactory response to proton pump inhibitors. These criteria underestimated the role of non-acid reflux. AIM To assess the contribution of impedance-pH with symptom association probability (SAP) analysis in identifying endoscopy-negative patients with reflux disease and separating them from functional heartburn. METHODS Consecutive endoscopy-negative patients treated with proton pump inhibitors (n=219) undergoing impedance-pH monitoring off-therapy were analysed. Distal acid exposure time, reflux episodes, SAP and symptomatic response to proton pump inhibitors were measured. RESULTS Based on impedance-pH/SAP, 67 (31%) patients were pH+/SAP+, 6 (2%) pH+/SAP-, 83 (38%) hypersensitive oesophagus and 63 (29%) functional heartburn. According to pH-metry alone/response to proton pump inhibitors, 62 (28%) were pH+/SAP+, 11 (5%) pH+/SAP-, 61 (28%) hypersensitive oesophagus and 85 (39%) functional heartburn. In the normal-acid exposure population the contribution of impedance-pH/SAP compared to pH-metry alone/response to proton pump inhibitors in identifying patients with reflux disease and functional heartburn resulted to be 10%. In patients with abnormal-acid exposure, the contribution of impedance-pH/SAP increased by 3%. CONCLUSION Comparing impedance-pH testing with pH-metry alone plus the response to proton pump inhibitor therapy demonstrated that the latter ones cause underestimation of reflux disease patients and overestimation of functional heartburn patients.