Markers of coagulation and fibrinolysis as measures of disease activity in inflammatory bowel disease

The Journey Through the Pathogenesis and Treatment of Venous Thromboembolism in Inflammatory Bowel Diseases: A Narrative Review

Inflammatory bowel diseases (IBDs) are chronic inflammatory disorders of the gastrointestinal tract including Crohn's disease and ulcerative colitis, which may result in several extraintestinal complications (∼20-30% of cases), such as increased risk of venous thromboembolism (VTE). The main pathophysiological mechanism of VTE is an inflammation-induced hypercoagulable state, and recent data have shown that endothelial dysregulation due to gut and systemic inflammation may also lead to a prothrombotic state. Several prothrombotic alterations have been described, such as the activation of the coagulation system, platelet abnormalities, and dysregulation of fibrinolysis. Furthermore, the dysregulation of the gut microbiome seems to play a vital role in increasing systemic inflammation and thus inducing a procoagulant state. Our review aims to examine the main correlations between IBD and VTE, the underlying pathophysiology, and current therapeutic options.

Altered functional responses by PAR1 agonist in murine dextran sodium sulphate-treated colon

Protease-activated receptor-1 (PAR1) is highly expressed in murine colonic smooth muscles. Responses to PAR1 activation are complex and result from responses in multiple cell types. We investigated whether PAR1 responses are altered in inflamed colon induced by dextran sodium sulfate (DSS)-treatment. Colitis was induced in C57BL/6 mice by administration of 3% DSS in drinking water for 7 days. Measurements of isometric force, transmembrane potentials from impaled smooth muscle cells, quantitative PCR and Western blots were performed. Thrombin, an activator of PAR1, caused transient hyperpolarization and relaxation of untreated colons, but these responses decreased in DSS-treated colons. Apamin caused depolarization and increased contractions of muscles from untreated mice. This response was decreased in DSS-treated colons. Expression of Kcnn3 and Pdgfra also decreased in DSS-treated muscles. A second phase of thrombin responses is depolarization and increased contractions in untreated muscles. However, thrombin did cause depolarization in DSS-treated colon, yet it increased colonic contractions. The latter effect was associated with enhanced expression of MYPT1 and CPI-17. The propagation velocity and frequency of colonic migrating motor complexes in DSS-treated colon was significantly higher compared to control colons. In summary, DSS treatment causes loss of transient relaxations due to downregulation of SK3 channels in PDGFRα⁺ cells and may increase contractile responses due to increased Ca²⁺ sensitization of smooth muscle cells via PAR1 activation.

Impact of Obesity on Inflammatory Bowel Disease

PURPOSE OF REVIEW

This review highlights recent work that evaluates the impact of obesity on inflammatory bowel disease (IBD) pathogenesis and management.

RECENT FINDINGS

The impact of obesity on IBD prevalence, clinical course, and management, has been studied and described more so in recent years. Studies have shown that obesity increases IBD disease activity, leads to longer hospitalization courses, and increases the likelihood of the development of extraintestinal manifestations. Recent evidence has also suggested that obese IBD patients have a higher frequency of extended steroid treatment and increased use of antibiotics compared to non-obese IBD patients. The effect of obesity on patients with IBD is a topic that has garnered widespread interest in the last decade due to the increasing prevalence of both diseases. To date however, although there are still many unanswered questions. It is quite clear that obesity, and more specifically, visceral adiposity, affects numerous IBD-related outcomes in regard to pathogenesis, extra-intestinal manifestations, response to medical and surgical therapies, hospital length of stay, healthcare-related costs, and health-related quality of life. Future studies should include larger patient populations and evaluate additional factors that are altered in those with obesity including the gut microbiome, dietary patterns, and whether weight loss and/or degree of weight loss impact clinical outcomes.

Safety of Venous Thromboprophylaxis With Low-molecular-weight Heparin in Children With Ulcerative Colitis

OBJECTIVES

To evaluate for increased rectal bleeding following enoxaparin thromboprophylaxis in children hospitalized for ulcerative colitis (UC).

METHODS

Retrospective cohort study (2007--2016) of 218 inpatients with active UC. Patients receiving enoxaparin were compared with a nonenoxaparin-treated patient group. Severity of UC was determined using the Pediatric Ulcerative Colitis Activity Index (PUCAI). Hemoglobin (Hb) values and packed red blood cell (pRBC) transfusions were reviewed for a 7-day period following hospital admission. A linear mixed effect model was used to compare change in Hb values between the groups. Risk of pRBC transfusion was compared using a log-rank test and Cox proportional hazard regression. A sub-analysis was also conducted restricting to patients with severe UC to provide more generalizable insight into safety profile of enoxaparin.

RESULTS

Children hospitalized for UC and receiving enoxaparin were more likely to have severe disease, received infliximab therapy and be admitted after 2010. Use of enoxaparin showed there was not a difference (P = 0.60) in the fall of Hb detected among those with acute severe colitis (initial PUCAI ≥65) during the week following admission. Moreover, there was no difference in the risk of requiring a pRBC transfusion with enoxaparin use (log-rank test all patients: P = 0.80; severe UC: P = 0.88; Cox proportional hazard regression all patients: P = 0.72; severe UC: 0.85).

CONCLUSIONS

There was no difference in Hb levels or need for blood transfusions in children hospitalized for severe UC (PUCAI ≥65) whether or not they received enoxaparin for thromboembolism prophylaxis.

Thromboembolic and atherosclerotic cardiovascular events in inflammatory bowel disease: epidemiology, pathogenesis and clinical management

Inflammatory bowel disease (IBD) is associated with an increased risk of cardiovascular disease (CVD). The increased risk of CVD concerns an increased risk of venous thromboembolism (VTE), atherosclerotic cardiovascular disease (ASCVD) and heart failure (HF), at corresponding relative risks of 2.5, 1.2 and 2.0, respectively, as compared with the general population. Especially young patients under the age of 40 years run a relatively high risk of these complications when compared with the general population. Chronic systemic inflammation causes a hypercoagulable state leading to the prothrombotic tendency characteristic of VTE, and accelerates all stages involved during atherogenesis in ASCVD. Increased awareness of VTE risk is warranted in patients with extensive colonic disease in both ulcerative colitis and Crohn's disease, as well as during hospitalization, especially when patients are scheduled for surgery. Similarly, critical periods for ASCVD events are the 3 months prior to and 3 months after an IBD-related hospital admission. The increased ASCVD risk is not fully explained by an increased prevalence of traditional risk factors and includes pro-atherogenc lipid profiles with high levels of small dense low-density lipoprotein cholesterol particles and dysfunctional high-density lipoprotein cholesterol. Risk factors associated with HF are location and extent of inflammation, female sex, and age exceeding 40 years. A dose-dependent increase of overall CVD risk has been reported for corticosteroids. Immunomodulating maintenance therapy might reduce CVD risk in IBD, not only by a direct reduction of chronic systemic inflammation but possibly also by a direct effect of IBD medication on platelet aggregation, endothelial function and lipid and glucose metabolism. More data are needed to define these effects accurately. Despite accumulating evidence on the increased CVD risk in IBD, congruent recommendations to develop preventive strategies are lacking. This literature review provides an overview of current knowledge and identifies gaps in evidence regarding CVD risk in IBD, by discussing epidemiology, pathogenesis, and clinical management.

Shedding Light on Hemostasis in Patients With Inflammatory Bowel Diseases

Patients with inflammatory bowel diseases (IBD) have an increased risk of thrombosis, possibly due to changes in blood cells and molecules involved in hemostasis. They have increased platelet counts and reactivity as well as increased platelet-derived large extracellular vesicles. Coagulation is continuously activated in patients with IBD, based on measured markers of thrombin generation, and the anticoagulant functions of endothelial cells are damaged. Furthermore, fibrinogen is increased and fibrin clots are denser. However, pathogenesis of thrombosis in patients with IBD appears to differ from that of patients without IBD. Patients with IBD also take drugs that might contribute to risk of thrombosis, complicating the picture. We review the features of homeostasis that are altered in patients with IBD and possible mechanisms of this relationship.

Risk of Venous Thromboembolism After Hospital Discharge in Patients With Inflammatory Bowel Disease: A Population-based Study

BACKGROUND

Inflammatory bowel disease (IBD) is associated with a high risk of venous thromboembolism (VTE) during hospitalization. It is unclear if this association persists after discharge. We aimed to assess the incidence of postdischarge VTE in IBD patients and to determine if IBD is associated with increased VTE risk.

METHODS

We performed a population-based cohort study between 2002 and 2016 using Ontario health administrative data sets. Hospitalized (≥72 hours) adults with IBD were stratified into nonsurgical and surgical cohorts and matched on propensity score to non-IBD controls. Time to postdischarge VTE was assessed by Kaplan-Meier methods, and VTE risk was assessed by Cox proportional hazard models.

RESULTS

A total of 81,900 IBD discharges (62,848 nonsurgical and 19,052 surgical) were matched to non-IBD controls. The cumulative incidence of VTE at 12 months after discharge was 2.3% for nonsurgical IBD patients and 1.6% for surgical IBD patients. The incidence increased in the nonsurgical IBD cohort by 4% per year (incidence rate ratio, 1.04; 95% CI, 1.02-1.05). In our propensity score-matched analysis, the risk of VTE at 1-month postdischarge was greater in nonsurgical IBD patients (hazard ratio [HR], 1.72; 95% CI, 1.51-1.96) and surgical patients with ulcerative colitis (HR, 1.68; 95% CI, 1.16-2.45) but not surgical patients with Crohn's disease. These trends persisted through 12 months.

CONCLUSIONS

Nonsurgical IBD patients and surgical patients with ulcerative colitis are 1.7-fold more likely to develop postdischarge VTE than non-IBD patients. These findings support the need for increased vigilance and consideration of thromboprophylaxis in this population.

Experimental and Clinical Evidence of Endothelial Dysfunction in Inflammatory Bowel Disease

The endothelium has a crucial role in proper hemodynamics. Inflammatory bowel disease (IBD) is mainly a chronic inflammatory condition of the gastrointestinal tract. However, considerable evidence points to high cardiovascular risk in patients with IBD. This review positions the basic mechanisms of endothelial dysfunction in the IBD setting (both clinical and experimental). Furthermore, we review the main effects of drugs used to treat IBD in endothelial (dys)function. Moreover, we leave challenging points for enlarging the therapeutic arsenal for IBD with new or repurposed drugs that target endothelial dysfunction besides inflammation.

The incidence and risk factors of venous thromboembolism in Japanese inpatients with inflammatory bowel disease: a retrospective cohort study

Background/Aims

Venous thromboembolism (VTE) is a major extraintestinal manifestation in inflammatory bowel disease (IBD), regarded as an independent risk factor for VTE according to reports from Western countries. However, the incidence and risk factors of VTE in Asian IBD patients are not fully understood. We aimed to reveal the incidence and risk factors of VTE in Japanese IBD inpatients.

Methods

The incidence of VTE in inpatients with IBD (n=340), gastrointestinal cancers (n=557), and other gastrointestinal diseases (n=569) treated at our hospital from 2009 to 2013 was retrospectively investigated. The characteristics and laboratory data of IBD inpatients with and without VTE were compared in univariate and multivariate analyses. Clinical courses of VTE in IBD were surveyed.

Results

VTE was detected in 7.1% of IBD inpatients, significantly higher than in gastrointestinal cancer inpatients (2.5%) and inpatients with other gastrointestinal diseases (0.88%). The incidence of VTE in ulcerative colitis (UC) patients (16.7%) was much higher than that in those with Crohn's disease (3.6%). In the univariate analysis, the risk factors were an older age, central venous catheter, prednisolone, surgery, low serum albumin, high serum C-reactive protein and D-dimer. According to a multivariate analysis, >50 years of age and surgery were the only risk factors. The in-hospital mortality rate of IBD inpatients with VTE was 4.2%.

Conclusions

The incidence of VTE with IBD, especially UC, was found to be high compared with other digestive disease, which was almost equivalent to that of Western countries. The efficacy of prophylaxis needs to be investigated in Asian IBD patients.

Proteomic Analysis of Serum Amyloid A as a Potential Marker in Intestinal Behçet's Disease

BACKGROUND/AIMS

Data regarding biomarkers to understand disease pathogenesis and to assess disease activity of intestinal Behçet's disease (BD) are limited. Therefore, we aimed to investigate the differentially expressed proteins in sera from patients with intestinal BD and to search for biomarkers using mass spectrometry-based proteomic analysis.

METHODS

Serum samples were pooled for the screening study, and two-dimensional electrophoresis (2-DE) was performed to characterize the proteins present in intestinal BD patients. Candidate protein spots were identified using matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry (MALDI-TOF/TOF MS) and bioinformatic analysis. To validate the proteomic results, serum samples from an independent cohort were assessed by enzyme-linked immunosorbent assay.

RESULTS

Pooled serum samples were used for 2-DE, and approximately 400 protein spots were detected in the sera of intestinal BD patients. Of the 22 differentially expressed proteins, 3 were successfully identified using MALDI-TOF/TOF MS. The three up-regulated proteins identified in the intestinal BD group included fibrin, apolipoprotein A-IV, and serum amyloid A (SAA). Serum SAA in intestinal BD patients (2.76 ± 2.50 ng/ml) was significantly higher than that in controls (1.68 ± 0.90 ng/ml, p = 0.007), which is consistent with the proteomic results. In addition, the level of IL-1β in patients with intestinal BD (8.96 ± 1.23 pg/ml) was higher than that in controls (5.40 ± 0.15 pg/ml, p = 0.009). SAA released by HT-29 cells was markedly increased by tumor necrosis factor-α (TNF-α) and lipopolysaccharides stimulation.

CONCLUSIONS

Our proteomic analysis revealed that SAA was up-regulated in intestinal BD patients.

Thrombosis in the setting of obesity or inflammatory bowel disease

Obesity and inflammatory bowel disease (IBD) are systemic inflammatory disorders that predispose to arterial and venous thrombosis through similar prothrombotic mechanisms. Obesity and IBD are chronic risk factors that lead to a persistently elevated risk of thrombosis, although the thrombotic risk with IBD appears to wax and wane with disease severity. Because of the lack of high-quality evidence to guide management decisions, approaches to the prevention and treatment of thrombosis in patients with obesity or IBD are based on extrapolation from general guidelines for antithrombotic therapy. Obesity alters the pharmacokinetics of some anticoagulant drugs, and IBD patients present the added management challenge of having a high risk of gastrointestinal bleeding while taking anticoagulants. An extended duration of anticoagulant therapy is often recommended for obese or IBD patients with unprovoked venous thromboembolism unless there is a high risk of bleeding, although more data and better biomarkers are needed to determine whether anticoagulation can be safely stopped in a subset of IBD patients during remission of active disease. Most patients with obesity or IBD require thromboprophylaxis in conjunction with hospitalization or surgery, with adjustment of anticoagulant dosing in patients with severe obesity.

Thrombosis in the setting of obesity or inflammatory bowel disease

Obesity and inflammatory bowel disease (IBD) are systemic inflammatory disorders that predispose to arterial and venous thrombosis through similar prothrombotic mechanisms. Obesity and IBD are chronic risk factors that lead to a persistently elevated risk of thrombosis, although the thrombotic risk with IBD appears to wax and wane with disease severity. Because of the lack of high-quality evidence to guide management decisions, approaches to the prevention and treatment of thrombosis in patients with obesity or IBD are based on extrapolation from general guidelines for antithrombotic therapy. Obesity alters the pharmacokinetics of some anticoagulant drugs, and IBD patients present the added management challenge of having a high risk of gastrointestinal bleeding while taking anticoagulants. An extended duration of anticoagulant therapy is often recommended for obese or IBD patients with unprovoked venous thromboembolism unless there is a high risk of bleeding, although more data and better biomarkers are needed to determine whether anticoagulation can be safely stopped in a subset of IBD patients during remission of active disease. Most patients with obesity or IBD require thromboprophylaxis in conjunction with hospitalization or surgery, with adjustment of anticoagulant dosing in patients with severe obesity.

Etiopathogenesis, Prevention, and Treatment of Thromboembolism in Inflammatory Bowel Disease

The close relationship between inflammation and thrombosis affects the progression and severity of inflammatory bowel disease (IBD). The prevalence of venous thromboembolism (VTE) varies between 1% and 7% among patients with IBD. The VTE risk in patients with IBD is at least 3 times higher than that in the normal general population. The absolute risk is very high during hospitalization, active disease, and surgery. The IBD-related VTE occurs at younger ages and recurs more frequently. The development of thrombosis in IBD is due to the interaction of many hereditary and acquired risk factors. Each patient diagnosed with IBD should be evaluated for a personal and family history of thrombosis and for prothrombotic drug use. Although procoagulant factors are increased during the natural course of inflammation, natural anticoagulants and fibrinolytic activity are decreased. Although IBD is accepted as a prothrombotic condition, there is no treatment that can remove this risk from daily practice. Patient training is required to control important factors, such as long-term immobilization and smoking. Oral contraceptives and hormone replacement therapy should be avoided. Inducing permanent disease remission must be the key approach for the prevention of thrombosis. Low-molecular-weight heparin (LMWH) is the basis of prophylactic treatment, which reduces the thrombosis risk by 50%. Prophylaxis with LMWH should be administered to all patients with IBD hospitalized due to disease attack or surgery. Long-term or even life-long anticoagulation therapy should be planned if there is insufficient disease control, recurrent VTE attacks, positive thrombophilia tests, or thrombosis in vital veins.

Plasma Thrombin-activatable Fibrinolysis Inhibitor Levels Correlate with the Disease Activity of Ulcerative Colitis

Objective Patients with ulcerative colitis (UC) are at an increased risk for thromboembolic events, particularly in patients with extensive and active disease. To date, a few studies have been published on the role of thrombin-activatable fibrinolysis inhibitor (TAFI) in UC. However, there are no reports in the literature investigating the effect of UC treatment on plasma TAFI levels. Methods The plasma TAFI antigen levels were quantitatively determined using ELISA kits for 20 UC patients at activation and remission, along with 17 healthy controls. The association between the TAFI levels and inflammatory markers was assessed to determine UC activation. To predict and determine the activation of UC, the Truelove-Witts index and the endoscopic activation index (EAI) were used for each subject. Results The plasma TAFI levels were higher in UC patients at activation of the disease compared with the remission state and in healthy controls. Spearman's correlation analyses revealed that the WBC (r: 0.586, p<0.001), hsCRP (r: 0.593, p<0.001) and EAI (r: 0.721, p<0.001) were significantly correlated with the TAFI levels. The overall accuracy of TAFI in determining UC activation was 82.5% with a sensitivity, specificity, NPV and PPV of 80%, 85%, 81% and 84.2%, respectively (cut-off value: 156.2% and AUC: 0.879). Conclusion The present study demonstrates that the TAFI levels are elevated in the active state of UC. The assessment of TAFI levels in patients with UC in conjunction with other markers of inflammation may provide additional information for estimating UC activation and severity.

Inflammatory bowel disease and thrombosis

Inflammatory Bowel Disease (IBD) is a group of chronic and relapsing inflammatory disorders of the gastrointestinalsystem. In these cases, findings are detected in extraintestinal systems also. There is a tendency for thrombotic eventsin IBD, as in the other inflammatory processes. The pathogenesis of this thrombotic tendency is multidimensional,including lack of natural anticoagulants, prothrombotic media induced via the inflammatory process, long-termsedentary life style, steroid use, surgery, and catheter placement. The aim of this review was to highlight the positiverelationship between IBD and thrombotic events, and the proper treatment of at-risk patients.

Activated thrombin activatable fibrinolysis inhibitor (TAFIa) is associated with inflammatory markers in inflammatory bowel diseases TAFIa level in patients with IBD

BACKGROUND

Thrombin activatable fibrinolysis inhibitor (TAFI) has been reported to be involved in the pathogenesis and progression of inflammatory bowel disease (IBD). Activated TAFI (TAFIa) attenuates fibrinolysis by cleaving C-terminal lysine residues thus down-regulating plasminogen activation. To date, no reports on TAFIa in IBD have been published.

METHODS

Plasma levels of TAFIa were measured using a functional assay in 55 consecutive patients with ulcerative colitis (UC) and 50 with Crohn's disease (CD). Associations of TAFIa with disease activity, hemostatic variables and inflammatory markers were assessed.

RESULTS

Plasma TAFIa was higher in CD patients than in those with UC. The disease activity correlated positively with TAFIa levels in the UC group, but not in the CD group. In UC patients, there were positive correlations of TAFIa with white blood cells, C-reactive protein and fibrinogen and an inverse correlation with albumin. In the CD group, a positive correlation was shown for C-reactive protein, fibrinogen and platelet count, while a negative correlation was noted for albumin.

CONCLUSIONS

This study is the first to show that TAFIa is increased in CD patients compared with UC and its levels are associated with inflammatory markers in both forms of IBD. These findings fit in the hypothesis that TAFIa may be a marker of active IBD, and in particular of active UC.

Continuous active state of coagulation system in patients with nonthrombotic inflammatory bowel disease

This study was planned for searching possible changes of the total coagulation and fibrinolysis system in inflammatory bowel disease (IBD) in order to obtain some clues for explaining the relation between IBD and hypercoagulability. A total of 24 patients with ulcerative colitis, 12 patients with Crohn disease, and 20 healthy controls were studied. Platelets; prothrombin time (PT); partial thromboplastin time (PTT); fibrinogen; D-dimer; fibrinogen degradation products; protein C; protein S; antithrombin; thrombin time; von Willebrand factor; coagulation factors V, VII, VIII, IX, XI, and XIII; plasminogen; antiplasmin; tissue plasminogen activator; plasminogen activator inhibitor 1; and prothrombin fragments 1 + 2 were studied. Most of the procoagulants (platelets, fibrinogen, von Willebrand factor, coagulation factor IX, and plasminogen activator inhibitor 1) were found increased together with decreases in some anticoagulants (protein S and antithrombin) in IBD. Also the activation markers of coagulation (D-dimer, fibrinogen degradation products, and prothrombin fragments 1 + 2) were all increased. The parameters of the total coagulation-fibrinolysis system were increased in IBD, regardless of the form and the activity of the disease.

Coagulation and inflammation. Molecular insights and diagnostic implications

Overwhelming evidence has linked inflammatory disorders to a hypercoagulable state. In fact, thromboembolic complications are among the leading causes of disability and death in many acute and chronic inflammatory diseases. Despite this clinical knowledge, coagulation and immunity were long regarded as separate entities. Recent studies have unveiled molecular underpinnings of the intimate interconnection between both systems. The studies have clearly shown that distinct pro-inflammatory stimuli also activate the clotting cascade and that coagulation in turn modulates inflammatory signaling pathways. In this review, we use evidence from sepsis and inflammatory bowel diseases as a paradigm for acute and chronic inflammatory states in general and rise hypotheses how a systematic molecular understanding of the "inflammation-coagulation" crosstalk may result in novel diagnostic and therapeutic strategies that target the inflammation-induced hypercoagulable state.

Systematic review on the effect of glucocorticoid use on procoagulant, anti-coagulant and fibrinolytic factors

BACKGROUND

Whether glucocorticoid use contributes to a hypercoagulable state, and thereby enhances the thrombotic risk, is controversial.

OBJECTIVE

We aimed to examine the effects of glucocorticoid use on coagulation and fibrinolysis.

METHODS

MEDLINE and EMBASE databases were searched to identify published studies comparing glucocorticoid treatment with a glucocorticoid-free control situation. Subjects could be either patients or healthy volunteers. Two investigators independently performed study selection and data extraction. Results were expressed as standardized mean difference, if possible; data were pooled with a random-effects model.

RESULTS

Of the 1967 identified publications, 36 papers were included. In healthy volunteers, a clear rise in factor (F)VII, VIII and XI activity was observed after glucocorticoid treatment, but these data alone provided insufficient evidence to support hypercoagulability. However, during active inflammation, glucocorticoids significantly increased levels of plasminogen activator inhibitor-1 (PAI-1), whereas levels of von Willebrand factor (VWF) and fibrinogen decreased. Peri-operative use of glucocorticoids inhibited the increase in tissue-type plasminogen activator induced by surgery.

CONCLUSIONS

The present study showed differential effects of glucocorticoids depending on the clinical situation in which it is given, most likely as a result of their disease modifying properties. Clinical outcome studies are needed to adequately assess the risk-benefit of glucocorticoid use per population when thrombotic complication is the focus.

Biomarkers of altered coagulation and fibrinolysis as measures of disease activity in active inflammatory bowel disease: a gender-stratified, cohort analysis

BACKGROUND

Growing evidence recognizes inflammatory bowel disease (IBD) as a chronic inflammatory condition characterized by a hypercoagulable state and prothrombotic conditions. The aims of our study were to evaluate the abnormalities in coagulation and fibrinolysis status in patients with IBD, and to analyze parameters of altered coagulation and fibrinolysis status which can correlated with and predict inflammatory parameters of disease activity.

METHODS

A cohort of 271 consecutive IBD patients was compared with healthy controls for coagulation and fibrinolysis status. Associations between altered coagulation and fibrinolysis status stratified by gender and inflammatory parameters were analyzed.

RESULTS

The mean levels of platelet, platelet distribution width, prothrombin time, fibrinogen, activated partial thromboplastin time were significantly higher in IBD patients than in healthy controls (all P<0.05). Mean platelet volume was lower in male patients with IBD than in healthy controls (P<0.01). Furthermore, multiple linear regression indicated that fibrinogen was an independent predictor of ESR (beta=1.316, P=<0.001) and CRP (beta=1.233, P=0.015) in male patients with active ulcerative colitis. Platelet (beta=0.436, P=0.037) and prothrombin time (beta=0.810, P=<0.001) were predictors of Crohn's Disease Activity Index in female patients with Crohn's disease.

CONCLUSIONS

To our knowledge, this study provides characteristics on altered coagulation and fibrinolysis status in active IBD patients using the largest number of cases assembled in one study to date. Our data suggest that in IBD patients, abnormalities in coagulation and fibrinolysis status were associated with disease activity. Fibrinogen, platelet and prothrombin time were predictors of inflammation.

Activations of coagulation and fibrinolysis secondary to bowel inflammation in patients with ulcerative colitis

BACKGROUND

Recent investigations suggest that activation of coagulation and fibrinolysis occurs in patients with ulcerative colitis (UC). However, the role of the hypercoagulable state in UC has not been determined. On the other hand, there are no reports dealing with coagulation in ischemic colitis (IC), in which acute bowel inflammation and reversible vascular occlusion affect the colon. Thus, our aim was to evaluate the hyper states of coagulation and fibrinolysis in UC by comparing activations of coagulation and fibrinolysis in patients with active UC and in those with IC.

METHODS

Twenty-four patients with active UC and 12 patients with IC were studied, with 18 patients with inactive UC serving as controls. We investigated the activation of the coagulation system, including platelet counts, activated partial thromboplastin time (APTT), thrombin time (TT), prothrombin time (PT), serum concentrations of von Willebrand factor (vWF), activated factors XII, XI, X, IX, VIII, VII, V, II, fibrinogen, prothrombin fragments 1+2 (F1+2), thrombin-antithrombin complexes (TAT), protein S, protein C, plasminogen, alpha-2 plasminogen inhibitor (alpha-2PI) and D-dimer (D-D).

RESULTS

Median serum vWF concentrations, F1+2, TAT, fibrinogen, activated factor XI, IX, VIII and V were significantly elevated in patients with active UC and IC compared to those in patients with inactive UC. There was no significant difference between active UC and IC patients in the mean values of any of the factors that were measured.

CONCLUSION

The results of the present study indicate that the coagulation-fibrinolysis system is activated in patients with active bowel inflammation such as active UC and IC, and that the hyper states of coagulation and fibrinolysis in patients with active UC are secondary to bowel inflammation.

Low-molecular-weight heparin (enoxaparin) as adjuvant therapy in the treatment of active ulcerative colitis: a randomized, controlled, comparative study

BACKGROUND

Heparin could be beneficial to the treatment of active ulcerative colitis because of its anticoagulant, anti-inflammatory and immunomodulatory properties.

AIM

To evaluate the tolerability, safety and efficacy of low-molecular-weight heparin as adjuvant therapy in patients with active ulcerative colitis.

METHODS

Thirty-four adult patients with active ulcerative colitis were consecutively included in a prospective, randomized, comparative study, and were treated for 12 weeks. Eighteen patients in the 'standard therapy' group were treated with aminosalicylates and weekly tapered corticosteroids. Sixteen patients in the 'heparin therapy' group were treated with standard therapy plus enoxaparin 100 Anti-Xa IU/kg/day subcutaneously.

RESULTS

Seventeen patients in the 'standard therapy' group and 15 patients in the 'heparin therapy' group completed the study. Tolerability and compliance to therapy were excellent and no withdrawals were noted because of complications. There was a significant improvement in the disease severity in both groups (P<0.001), without any difference between them (P=not significant). Both treatment groups showed similar proportions of disease improvement (65% and 73%, respectively; P=not significant). There were no significant differences in inflammation (fibrinogen, ESR, CRP) and coagulation (thrombin-antithrombin complex, F1+2, D-dimers) parameters during and at the end of the study between treatment groups.

CONCLUSION

Adjuvant administration of low-molecular heparin in patients with active ulcerative colitis is safe and well tolerated, but no additive benefit over standard therapy for ulcerative colitis was noted.

Elevated plasma von Willebrand factor levels in patients with active ulcerative colitis reflect endothelial perturbation due to systemic inflammation

AIM

To evaluate the plasma von Willebrand factor (vWF) levels in patients with ulcerative colitis (UC) and to investigate their relationship with disease activity, systemic inflammation and coagulation activation.

METHODS

In 46 patients with ulcerative colitis (active in 34 patients), clinical data were gathered and plasma vWF levels, markers of inflammation (ESR, CRP, and fibrinogen) and thrombin generation (TAT, F1+2, and D-dimers) were measured at baseline and after 12 wk of treatment. Plasma vWF levels were also determined in 52 healthy controls (HC). The relationship of plasma vWF levels with disease activity, disease extent, response to therapy, acute-phase reactants (APRs) and coagulation markers (COAGs) was assessed.

RESULTS

The mean plasma vWF concentrations were significantly higher in active UC patients (143.38+/-63.73%) than in HC (100.75+/-29.65%, P = 0.001) and inactive UC patients (98.92+/-43.6%, P = 0.031). ESR, CRP and fibrinogen mean levels were significantly higher in active UC patients than in inactive UC patients, whereas there were no significant differences in plasma levels of D-dimers, F1+2, and TAT. UC patients with raised APRs had significantly higher mean plasma vWF levels than those with normal APRs (144.3% vs 96.2%, P = 0.019), regardless of disease activity. Although the mean plasma vWF levels were higher in UC patients with raised COAGs than in those with normal COAGs, irrespective of disease activity, the difference was not significant (141.3% vs 118.2%, P = 0.216). No correlation was noted between plasma vWF levels and disease extent. After 12 wk of treatment, significant decreases of fibrinogen, ESR, F1+2, D-dimers and vWF levels were noted only in UC patients with clinical and endoscopic improvement.

CONCLUSION

Our data indicate that increased plasma vWF levels correlate with active ulcerative colitis and increased acute-phase proteins. Elevated plasma vWF levels in ulcerative colitis possibly reflect an acute-phase response of the perturbed endothelium due to inflammation. In UC patients, plasma vWF levels may be another useful marker of disease activity or response to therapy.

Disseminated intravascular coagulation in an ambulatory young woman

We are reporting the case of an ambulatory young woman with a 10-year history of recurrent venous thrombosis who presented to us with diffuse intravascular coagulation (DIC). After excluding the recognized causes of DIC, we examined the possibility that her clinically quiescent ulcerative colitis might be the underlying stimulus. We documented sepsis-range endotoxemia in this patient at a time when she was afebrile and had a normal C-reactive protein level. In vitro her serum upregulated tissue factor in cultured endothelial cells. We postulate that she had become tolerant to the systemic effects of endotoxin leaking from her inflamed colon but that the endotoxin stimulated her endothelium and/or monocytes to produce tissue factor that made her intensely hypercoagulable. Her prothrombotic state may have been compounded by the fact that she was heterozygous for prothrombin G20210A and that her plasma clotting time demonstrated resistance to activated protein C.

Mast cell tryptase controls paracellular permeability of the intestine. Role of protease-activated receptor 2 and beta-arrestins

Tight junctions between intestinal epithelial cells prevent ingress of luminal macromolecules and bacteria and protect against inflammation and infection. During stress and inflammation, mast cells mediate increased mucosal permeability by unknown mechanisms. We hypothesized that mast cell tryptase cleaves protease-activated receptor 2 (PAR2) on colonocytes to increase paracellular permeability. Colonocytes expressed PAR2 mRNA and responded to PAR2 agonists with increased [Ca2+]i. Supernatant from degranulated mast cells increased [Ca2+]i in colonocytes, which was prevented by a tryptase inhibitor, and desensitized responses to PAR2 agonist, suggesting PAR2 cleavage. When applied to the basolateral surface of colonocytes, PAR2 agonists and mast cell supernatant decreased transepithelial resistance, increased transepithelial flux of macromolecules, and induced redistribution of tight junction ZO-1 and occludin and perijunctional F-actin. When mast cells were co-cultured with colonocytes, mast cell degranulation increased paracellular permeability of colonocytes. This was prevented by a tryptase inhibitor. We determined the role of ERK1/2 and of beta-arrestins, which recruit ERK1/2 to PAR2 in endosomes and retain ERK1/2 in the cytosol, on PAR2-mediated alterations in permeability. An ERK1/2 inhibitor abolished the effects of PAR2 agonist on permeability and redistribution of F-actin. Down-regulation of beta-arrestins with small interfering RNA inhibited PAR2-induced activation of ERK1/2 and suppressed PAR2-induced changes in permeability. Thus, mast cells signal to colonocytes in a paracrine manner by release of tryptase and activation of PAR2. PAR2 couples to beta-arrestin-dependent activation of ERK1/2, which regulates reorganization of perijunctional F-actin to increase epithelial permeability. These mechanisms may explain the increased epithelial permeability of the intestine during stress and inflammation.

A role for proteinase-activated receptor-1 in inflammatory bowel diseases

Proteinase-activated receptor-1 (PAR1), a G protein-coupled receptor activated by thrombin, is highly expressed in different cell types of the gastrointestinal tract. The activity of thrombin and of other proteinases is significantly increased in the colon of inflammatory bowel disease (IBD) patients. Since PAR1 activation in tissues other than the gut provoked inflammation, we hypothesized that PAR1 activation in the colon is involved in the pathogenesis of IBD. Here, we demonstrate that PAR1 is overexpressed in the colon of IBD patients. In mice, intracolonic administration of PAR1 agonists led to an inflammatory reaction characterized by edema and granulocyte infiltration. This PAR1 activation-induced inflammation was dependent on B and T lymphocytes. Moreover, PAR1 activation exacerbated and prolonged inflammation in a mouse model of IBD induced by the intracolonic administration of trinitrobenzene sulfonic acid (TNBS), while PAR1 antagonism significantly decreased the mortality and severity of colonic inflammation induced by TNBS and dextran sodium sulfate. In these 2 models, colitis development was strongly attenuated by PAR1 deficiency. Taken together, these results imply an important role for PAR1 in the pathogenesis of experimental colitis, supporting the notion that PAR1 inhibition may be beneficial in the context of IBD and possibly in other chronic intestinal inflammatory disorders.

Severe ulcerative colitis: prospective study of parameters determining outcome

BACKGROUND

One-third of patients with exacerbations of ulcerative colitis (UC) require colectomy and 1% die. Although several studies have reported parameters associated with failure of medical treatment, studies using multivariate analysis of various predictors are scanty.

METHODS

Demographic, clinical and laboratory parameters within 48 h of admission of 50 consecutive patients (55 episodes) were prospectively recorded. Each episode was treated with intravenous hydrocortisone, antibiotics and fluid administration. The data of patients who failed to respond, deteriorated, developed complications requiring emergency surgery or died within 7 days of hospitalization, were compared with the data of those who responded during this period using Mann-Whitney U-test or chi-squared tests. Variables found to be significant on univariate analysis were entered into a multivariate model.

RESULTS

Medical treatment failed in 10 of 55 episodes; eight had surgery (one died), another died with bowel perforation and peritonitis and one left hospital in a moribund state. Younger age, pedal edema, transverse colonic diameter >5 cm on abdominal radiograph, low hemoglobin, low serum albumin, high C-reactive protein, presence of fibrin degradation product (FDP) in serum, low serum fibrinogen, prolonged prothrombin time, Truelove-Witt's fulminant disease, and high clinical activity index were associated with failure of medical treatment on univariate analysis. All the above variables were significant by multivariate analysis except age, serum albumin level and presence of FDP.

CONCLUSION

It may be possible to predict the failure of medical treatment in exacerbations of UC using a scoring system based on clinical parameters and simple laboratory tests.

Assessment of thrombin-activatable fibrinolysis inhibitor (TAFI) plasma levels in inflammatory bowel diseases

OBJECTIVES

Hypofibrinolysis has been proposed as a possible mechanism underlying the known risk of thrombosis observed in patients with inflammatory bowel diseases (IBD). Thrombin-activatable fibrinolysis inhibitor (TAFI) is a recently described inhibitor of fibrinolysis. Increased TAFI plasma levels are associated with a risk for venous thrombosis. The objective was to evaluate TAFI plasma levels and their possible correlations with clinical features and acute-phase reactants in IBD patients.

METHODS

Eighty-one IBD patients (47 Crohn's disease and 34 ulcerative colitis) and 81 sex- and age-matched healthy controls were enrolled in the study; moreover, we studied 30 inflammatory controls (13 Reiter's syndrome, 4 Behçet's syndrome, and 13 patients with newly diagnosed celiac disease). TAFI plasma levels were assessed by means of a commercially available ELISA kit. Erythrocytes sedimentation rate, C-reactive protein, and alpha1-acid glycoprotein were measured as acute-phase reactants. Statistical analysis was performed by means of nonparametric tests and Fisher's exact test and chi(2) test for independence.

RESULTS

Median TAFI plasma levels were significantly higher in IBD patients (116.0%, range: 39.0-232.0%) and in inflammatory controls (176.0%, 50.0-435.0%) than in healthy controls (99.0%, 40.0-170.0%) (p< or = 0.05 and p< or = 0.001, respectively). TAFI plasma levels higher than the 95th percentile of control values were significantly more frequent in IBD patients (19.7%) and in inflammatory controls (53.3%) than in healthy controls (4.9%) (p< or = 0.008 and p< or = 0.0001, respectively) and more frequent in clinically active IBD than in clinically quiescent IBD (31.4%vs 10.9%, p< or = 0.03). Finally, in IBD, significant correlations were observed between TAFI plasma levels and erythrocytes sedimentation rate (p< or = 0.02), C-reactive protein (p< or = 0.001), and alpha1-acid glycoprotein (p< or = 0.05).

CONCLUSIONS

TAFI plasma levels are increased in IBD patients and correlate with acute-phase reactants. Increased TAFI plasma levels might contribute to the prothrombotic state observed in IBD through the induction of hypofibrinolysis.

Coagulation and fibrinolysis in inflammatory bowel disease and in giant cell arteritis

BACKGROUND

In inflammatory bowel disease (IBD), gut microvascular thrombosis as well as thromboembolic complications have repeatedly been observed. We examined the long-term course of markers of coagulation and fibrinolysis in relation to clinical disease activity.

MATERIALS AND METHODS

In a prospective study, prothrombin fragment 1 and 2 (F1.2), thrombin-antithrombin complex (TAT), antithrombin, D-dimer, plasmin-alpha(2)-antiplasmin complex (PAP) and plasminogen activator inhibitor-1 (PAI-1) were measured in 20 patients with Crohn's disease (CD), 18 with ulcerative colitis (UC), and 19 with giant cell arteritis during active and inactive disease, as well as in 51 controls without inflammation.

RESULTS

Levels of F1.2, TAT, D-dimer, PAP and PAI-1 were significantly higher in active versus inactive CD and UC. However, even after 12 months of follow-up, in CD and UC the mean levels of F1.2, D-dimer and PAP were significantly higher than the levels of the controls.

CONCLUSIONS

Levels of F1.2, D-dimer and PAP were markedly raised for a long time in clinically inactive IBD, underlining a chronic state of hypercoagulation and enhanced fibrinolysis.

The 4G/4G genotype of the 4G/5G polymorphism of the type-1 plasminogen activator inhibitor (PAI-1) gene is a determinant of penetrating behaviour in patients with Crohn's disease

BACKGROUND

Crohn's disease is a heterogeneous disorder with polygenic inheritance.

AIM

To assess the effect of the 4G/5G polymorphism of the type-1 plasminogen activator inhibitor (PAI-1) gene, the major inhibitor of fibrinolysis, on Crohn's disease susceptibility and phenotype.

METHODS

One hundred and fifty-seven patients with Crohn's disease and 350 controls were included prospectively. Medical records were reviewed to determine changes in the Crohn's disease phenotype. The 4G/5G polymorphism was assessed by polymerase chain reaction techniques.

RESULTS

The frequencies of the 4G/4G, 4G/5G and 5G/5G genotypes were similar in patients with Crohn's disease and controls. The 4G/4G genotype (P < 0.0001; odds ratio, 4.84) and male sex (P = 0.009; odds ratio, 2.63) were independent risk factors for penetrating behaviour in Crohn's disease. Most Crohn's disease patients had a non-penetrating phenotype at diagnosis. The probability of development of a penetrating phenotype within 5 years of diagnosis was higher in patients with the 4G/4G genotype (72% vs. 19%, P < 0.0001).

CONCLUSIONS

The 4G/4G genotype of the PAI-1 gene does not influence Crohn's disease susceptibility, but increases by five-fold the probability of penetrating behaviour. Most patients with the 4G/4G genotype have a non-penetrating phenotype at diagnosis, but develop a penetrating behaviour within 5 years. Genotyping the 4G/5G polymorphism may be useful for the identification of a sub-group of patients with aggressive Crohn's disease, who might benefit from specific therapy.

Persistent activation of coagulation and fibrinolysis after treatment of active ulcerative colitis

OBJECTIVE

Haemostatic changes may be involved in the pathogenesis and progression of ulcerative colitis. We studied longitudinally inflammatory and haemostatic parameters in patients treated for severe ulcerative colitis.

DESIGN AND SETTING

We carried out a descriptive study of longitudinal blood measurements in patients with severe ulcerative colitis from one large regional hospital.

METHODS

Nineteen patients with severe ulcerative colitis were assessed by an endoscopic score and a patient score at baseline. Patients were assessed by patient scores during treatment at scheduled intervals. At each visit, inflammatory and haemostatic parameters were determined.

RESULTS

At baseline, the erythrocyte sedimentation rate, C-reactive protein, leucocyte and granulocyte count, thrombin-antithrombin complexes, prothrombin fragment 1+2, fibrinogen and degradation products of fibrinogen and fibrin were increased in patients when compared with controls, whereas albumin concentration and factor XIII activity were significantly lower. Antithrombin activity was normal. During treatment, the median patient score diminished significantly from 12 to 4.5 points after 2 weeks, decreased further to 4 points after 4 weeks and remained below 4 points throughout the remaining study period. Inflammation parameters returned to within the reference range in two patients after 4 weeks, whereas the coagulation markers prothrombin fragment 1+2 and thrombin-antithrombin complexes returned to normal values after 8 weeks and 24 weeks, respectively. In contrast with markers of inflammation, slightly increased concentrations of the degradation products of both fibrinogen and fibrin were found for almost 1 year, which indicated low-grade activation of coagulation and fibrinolysis.

CONCLUSIONS

These results are compatible with a condition of persistent hypercoagulation in patients with ulcerative colitis who are in clinical remission. Persistent hypercoagulation may contribute to the clinical course of ulcerative colitis.

Platelets and anticoagulant capacity in patients with inflammatory bowel disease

Patients with inflammatory bowel disease (IBD) are susceptible to thromboembolic complications. Several mechanisms can be responsible, including abnormal regulation of coagulation activity, disturbances of fibrinolysis, inflammatory reactions and thrombocytosis. The aim of this study was to assess hemostatic alterations in these parameters during exacerbation of disease. We studied disease activity in 99 IBD patients receiving anti-inflammatory therapy, in relation to: procoagulant markers, i.e. prothrombin fragment F1 + 2 (F1 + 2), D-dimer and platelet count, anticoagulant markers, i.e. protein C, protein S and antithrombin, and a mediator of inflammation (IL-6). Coagulation activity and platelet count were increased during active disease in IBD patients compared with those in a state of remission. The IL-6 concentrations were positively correlated with disease activity and thrombocytosis in patients with ulcerative colitis, but no association with the anticoagulant capacity could be demonstrated except for a decrease in protein C during high disease activity.

Lipoprotein (a), thrombophilia and inflammatory bowel disease

Thrombophilia in inflammatory bowel disease may be due to several risk factors, such as a dysbalanced haemostasis with a hypercoagulative state, thrombocytosis, hyperfibrinogenaemia and hyperhomocysteinaemia. In addition, increased concentrations of lipoprotein (a), a modified form of low-density lipoprotein particles, have been associated with a higher risk of thrombotic vascular disease, probably due to inhibition of (local and endothelial) fibrinolysis. The mechanisms regulating the plasma concentration of lipoprotein (a) have not yet been elucidated completely, but genetic factors are involved. Dietary factors seem to play a minor role. In this issue of the journal, Koutroubakis et al. report that lipoprotein (a) concentration is elevated in patients with Crohn's disease, but not in patients with ulcerative colitis. Several other (apo)lipoproteins have a different pattern in patients with inflammatory bowel disease than in a control population of healthy subjects from Crete. These findings add up to the multifactorial nature of thrombophilia in inflammatory bowel disease patients, especially in patients with Crohn's disease, and give rise to speculations about the clinical significance of the observed different lipoprotein metabolism in patients with inflammatory bowel disease.

Role of thrombotic vascular risk factors in inflammatory bowel disease

Thromboembolic disease is a significant cause of morbidity and mortality in patients with inflammatory bowel disease (IBD). It is recognized that a hypercoagulable state exists in IBD which involves all components of the clotting system. It has been suggested that this hypercoagulable state is closely linked to the disease pathogenesis. Recent studies have shown that genetic defects such as factor V Leiden mutation and C677T methylenetetrahydrofolate reductase polymorphism associated with hyperhomocysteinemia seem to interfere in the thrombotic manifestations of IBD. Acquired factors such as antiphospholipid antibodies could also participate in the development of the thrombotic process. Deficiencies of other anticoagulant factors play a less important role in the thrombosis, and therefore it is not surprising that the results on these factors in IBD are contradictory. In conclusion the resultant gene-gene and gene-environment interactions between risk factors are the key to the understanding of why an IBD patient develops thrombosis at a specific point in time.

Hemostatic imbalance in active and quiescent ulcerative colitis

OBJECTIVE

In healthy conditions, factors inducing or inhibiting coagulation and factors inducing or inhibiting fibrinolysis are in balance. In ulcerative colitis, hypercoagulation is presumed, which may explain part of the clinical features of this disease. Therapy strategies affecting hemostasis may improve the course of ulcerative colitis. This study was conducted to evaluate the balance of coagulation and fibrinolysis in the course of treatment of active ulcerative colitis.

METHODS

Patients with active ulcerative colitis were studied by serial determination of markers of the coagulation cascade (thrombin-antithrombin complexes and fibrin degradation products [FbDP]) and the fibrinolytic cascade (fibrinogen degradation products [FgDP]). Parameters of inflammation were also measured (C-reactive protein [CRP], erythrocyte sedimentation rate [ESR], albumin, platelet count, and fibrinogen). Disease activity was assessed by endoscopic and histopathological scores. Follow-up measurement was performed in the course of treatment at the third or fourth month after baseline. Measurements were compared with healthy controls.

RESULTS

Thirty-three patients and 22 healthy controls were included. During active ulcerative colitis, inflammatory parameters (CRP, ESR, platelet count) and hemostatic parameters (thrombin-antithrombin complexes, fibrinogen, FgDP, and FbDP) were elevated in comparison with healthy controls. Albumin was decreased and antithrombin-III remained unchanged. During treatment, disease activity decreased significantly endoscopically and histopathologically (p < 0.001). CRP, ESR, platelet count, and fibrinogen also decreased significantly. The hemostatic balance, expressed as the ratio between the plasmin-dependent generation of FgDP and coagulation-dependent generation of FbDP, increased from 0.69 to 1.12 during treatment, mainly because of a decrease of FbDP. In healthy controls, this ratio was

CONCLUSIONS

The coagulation and fibrinolytic cascades were activated in active ulcerative colitis, with a hemostatic imbalance in favor of coagulation. This hypercoagulability persisted in 20% (7/33) of patients with ulcerative colitis in remission. The decrease of FbDP and the increase in the FgDP/FbDP ratio during reconvalescence of ulcerative colitis showed that the coagulation cascade was more activated than the fibrinolytic cascade in active disease.

Diagnostic markers of inflammatory bowel disease

The diagnosis of inflammatory bowel disease is usually straightforward, based on a detailed history and physical examination, along with standard radiographic and endoscopic investigations, biopsies, and laboratory parameters. More challenging is the search for clinically useful, noninvasive markers for Crohn disease and ulcerative colitis to accurately screen cases with nonspecific and indolent symptoms. Equally required are diagnostic markers that discriminate between these two disorders in cases with indeterminate colitis. Another dilemma for clinicians is that there are no simple measures to observe disease activity and predict relapses. This review describes the recent advances in diagnostic markers that afford the ability to screen for inflammatory bowel disease, discriminate between its types, and monitor disease activity. These include serological, fecal, and tissue markers; permeability tests; and diagnostic imaging using color Doppler ultrasonography.