Unraveling the mechanisms of thrombosis in inflammatory bowel disease

Low-Grade Activation of the Extrinsic Coagulation Pathway in Patients with Ulcerative Colitis

BACKGROUND

Ulcerative colitis (UC) increases the risk for venous thromboembolism. Tissue factor (TF) initiates the extrinsic coagulation pathway (ECP).

AIMS

To investigate the correlation of UC severity with latent ECP activation and TF expression in primary colonic stromal cells (PCSC).

METHODS

In plasma of 38 UC patients (31 males, disease duration 151 ± 25 months) and 28 healthy controls, exosomes and microparticles (EM) were counted. Moreover, TF protein concentration, activities of EM-bound TF (EM-TFa) and coagulation factor VII (FVIIa) were assessed. In PCSC in culture, TF mRNA (F3) from 12 patients with active UC and 7 controls was evaluated.

RESULTS

UC patients had 4- and 3.7- times more exosomes and microparticles, respectively, than controls. TF protein in UC was correlated with several disease severity indices, such as partial Mayo score (pMs; r 0.443), albumin (- 0.362), ESR (0.353), PLT (0.575), and endoscopic Ms (eMs 0.468). EM-TFa was also significantly higher in UC and was correlated to SIBDQ (- 0.64), albumin (- 0.624), disease extent and eMs (0.422). Refractory-to-treatment patients had significantly higher TF protein, EM-TFa and FVIIa. Even within responders, the need for steroids or biologics correlated with a 2.2-times higher EM-TFa. PCSC from active UC maintained higher F3 than controls, which was correlated to pMs (0.56), albumin (- 0.543) and eMs. Treatment with cytokines further upregulated F3. P for all comparisons was < 0.05.

CONCLUSION

Low-grade activation of the ECP associates with clinical, endoscopic UC activity and response to treatment. TF in PCSC mirrors its systemic activity and points to them as a source.

Identification of Antibody Against SNRPB, Small Nuclear Ribonucleoprotein-Associated Proteins B and B', as an Autoantibody Marker in Crohn's Disease using an Immunoproteomics Approach

BACKGROUND

Current non-invasive biomarkers for Crohn's disease are limited in their utility. Progress in identifying individual autoantigens and autoantibodies in Crohn's disease has been challenging due to limitations of available immunoassays.

AIMS

Our aim was to identify autoantibodies associated with Crohn's disease that may be useful in diagnosis and management using an innovative protein array technology, namely nucleic acid programmable protein arrays [NAPPA].

METHODS

Serum samples of 96 patients with established Crohn's disease and 96 healthy controls were included and evenly split into discovery and validation sets randomly. Autoantibodies of both IgG and IgA classes were profiled against ~1900 human proteins in the discovery set on NAPPA. Autoantibodies discovered to be Crohn's disease-specific were further validated in the independent validation set by enzyme-linked immunosorbent assay.

RESULTS

Overall, reactivity of IgG autoantibodies was stronger than that of IgA autoantibodies; however, IgA autoantibodies showed greater differential reactivity between cases and controls. Four IgA autoantibodies against SNRPB, PRPH, PTTG1 and SNAI1 were newly identified with sensitivities above 15% at 95% specificity, among which anti-SNRPB-IgA had the highest sensitivity of 24.0%. Autoantibodies associated with specific disease subtypes were also found.

CONCLUSIONS

As one of the first studies to use immunoproteomics for the identification of autoantibodies in Crohn's disease, our results support the utility of NAPPA in implementing future expanded studies with better coverage of the human proteome and microbial proteomes relevant to Crohn's disease and identifying antibody markers that may have clinical impact in diagnosis and management.

Thromboembolism in Dogs with Protein-Losing Enteropathy with Non-Neoplastic Chronic Small Intestinal Disease

Dogs with protein-losing enteropathy (PLE) are suggested to be at increased risk of developing thromboembolic events. However, with some exceptions, there are very few reports of thromboembolism in such dogs. This multicentre retrospective observational study describes a case series of thromboembolism (TE) in eight dogs with PLE secondary to non-neoplastic, chronic small intestinal disease. Seven dogs had poorly controlled PLE when the thromboembolic event occurred. Pulmonary thromboembolism (PTE) occurred in six dogs, while one dog developed splenic vein thrombosis and another had concurrent splenic vein and aortic TE. Six dogs died, all with PTE. Antithrombin activity was decreased in one of two dogs in which it was measured. Serum cobalamin and folate concentrations were measured in three dogs and cobalamin was subnormal in all three. Serum magnesium, measured in two dogs, was low in both. Dogs with uncontrolled chronic small intestinal disease and PLE are at risk for developing serious life-threatening TE, mostly PTE.

Embolic lower limb ischemia as a rare complication of ulcerative colitis: A case report and literature review

Thromboembolic events in chronic inflammatory bowel diseases are rare and predominated by venous damage. Arterial thromboembolic events are extremely uncommon. We are reporting the case of a 50-year-old male patient with an 8-year history of ulcerative colitis, who presented a recurring severe lower limb ischemia during hospital stay for exacerbation of his inflammatory bowel disease. During the first visit, the patient underwent a balloon thromboembolectomy via femoral approach, with fasciotomy of the leg. Because of recurrence of symptoms, he underwent a second and a third thromboembolectomy by a popliteal approach, with an uneventful postoperative course and was discharged home 10 days later, on warfarin therapy and oral corticosteroids. After an extensive literature review using PubMed, we found 20 reported cases in the English literature over the past 25 years; not including this present case. In the absence of major cardiovascular risk factors, inherited thrombophilia and intracardiac thrombi, we consider active ulcerative colitis to be the major trigger of the embolic lower limb ischemia in our patient. By means of this report, we seek to create awareness of the increased risk of arterial thromboembolism in inflammatory bowel diseases patients.

Long-term risk of mesenteric ischemia in patients with inflammatory bowel disease: a 13-year nationwide cohort study in an Asian population

BACKGROUND

It is unclear whether patients with inflammatory bowel disease (IBD) have higher risks of developing mesenteric ischemia.

METHODS

We enrolled 9,363 patients who had been hospitalized because of IBD between January 1998 and December 2010, along with 37,452 control patients who were matched at a 1:4 proportion for age, sex, and index year. We accounted the cumulative incidences and hazard ratios (HRs) of developing mesenteric ischemia during the 13-year study period.

RESULTS

Patients with IBD had a considerably higher incidence rate of subsequent mesenteric ischemia compared with the controls (22.7 vs 3.09 per 10,000 person-years), with adjusted HR of 6.33 (95% confidence interval: 4.75 to 8.43). A multivariate stratified analysis showed that the mesenteric ischemia risk after adjustment for comorbidities is significantly higher in patients of all age groups, particularly in patients younger than 44 years (adjusted HR: 48.0; 95% confidence interval: 11.3 to 203.9). Moreover, patients with IBD were at highest risk of developing mesenteric ischemia within the first year of follow-up.

CONCLUSIONS

Careful follow-up and effective therapy are necessary to reduce the excessive risk in these patients.

Long-term risk of acute coronary syndrome in patients with inflammatory bowel disease: a 13-year nationwide cohort study in an Asian population

BACKGROUND

Whether patients with inflammatory bowel disease (IBD) exhibit a higher risk of developing acute coronary syndrome (ACS) remains debatable.

METHODS

From the inpatient claims of Taiwan's National Health Insurance Research Database, we identified 11,822 patients with IBD symptoms in the 1998-2010 period and 47,288 control patients without the disorder, frequency matched by age, sex, and admission year. Both cohorts were followed-up until the end of 2010 to estimate the risk of ACS.

RESULTS

The incidence of ACS was 87% higher in the patients with IBD than in the control patients (5.76 versus 3.08 per 1000 person-years). The multivariable Cox proportional hazards regression model measured adjusted hazard ratios of ACS at 1.72 (95% confidence interval, 1.53-1.94) for the patients with IBD. The age-specific data showed that the adjusted hazard ratio for patients with IBD, compared with control patients, was the highest for the 20- to 39-year age group, at 3.28 (95% confidence interval, 1.73-6.22), which decreased to 1.70 (95% confidence interval, 1.45-1.99). Patients with IBD who, on average, required 2 or more hospitalization per year were nearly 20-fold more likely to have ACS than those who required 1 hospitalization per year (80.7 versus 4.10 per 1000 person-years).

CONCLUSIONS

The absolute risk of ACS increases sharply with age for patients with IBD, but young patients are at greater relative risk for the consequence. The risk of ACS was proportional to the severity of IBD. Careful follow-up observation and effective therapy should be sought for patients with IBD to reduce the risk of ACS.

Venous and arterial disease in inflammatory bowel disease

Awareness is increasing that risk of venous thromboembolism and development of atherosclerosis is elevated in patients with some chronic inflammatory diseases. This review aimed to examine the risk of vascular disease in patients with inflammatory bowel disease (IBD) and to identify potential pathogenic mechanisms and therapeutic approaches. An extensive literature search was conducted using MEDLINE database, Cochrane Library and international conference abstracts for studies pertaining to venous and arterial thromboembolism in adult IBD patients. There is a 1.1-3.6 fold risk of venothromboembolism in IBD, affecting 0.55-6.15% of patients. Risks are increased during a flare or with chronically active inflammation. Evidence is building that there may be a modestly increased risk of arterial disease overall, despite evidence that traditional risk factors may be reduced. Multiple pathogenic factors have been identified including endothelial dysfunction, inflammation-mediated calcium deposition in the media of arteries, hyperhomocysteinemia, platelet activation, and altered coagulation and fibrinolysis. The key to active and preventive therapy is to effectively treat inflammation. Recommendations for prophylaxis of venothromboembolism have followed guidelines where they exist and have been extrapolated from studies of other at-risk conditions, as have those for arterial disease, where screening for risk factors and actively treating abnormalities is encouraged. In conclusion, patients with IBD are at considerably increased risk of venothromboembolism and probably of arterial disease, in particular mesenteric ischemia and ischemic heart disease. Increased penetration of gaps between this knowledge and clinical therapeutic action to prevent thromboembolic events into IBD clinical practice is needed.

Protective effect of magnesium lithospermate B against dextran sodiumsulfate induced ulcerative colitis in mice

Anti-platelet drugs have been used to treat inflammatory bowel disease. In this study, we observed the therapeutic effects of magnesium lithospermate B, a main component of salvianolate, on colitis induced by dextran sodiumsulfate (DSS). Colitis was induced by 5% DSS oral administration in BALB/C male mice. Magnesium lithospermate B (60-240mg/kg) was given by subcutaneous injection for 2 weeks. Then, mice were sacrificed; serum and colon tissues were collected for biomarker assay, histological examination, immunohistochemical study and real-time quantitative polymerase chain reaction. DSS induced gross bleeding, inflammation, crypt damage and mucosal damage in colon. Treatment with magnesium lithospermate B could reduce colon inflammation induced by DSS. Magnesium lithospermate B could reverse the high CD40/CD40L expression and hypercoagulable state induced by DSS in colon. This study showed that magnesium lithospermate B could be used to treat colitis. The protective effects of magnesium lithospermate B may be due to its effects on CD40/CD40L expression and blood clotting status.

Thrombotic storm in a teenager with previously undiagnosed ulcerative colitis

Venous thrombosis can complicate inflammatory bowel diseases, both in adult and pediatric patients, and a few adult cases of thrombotic storm, ie, thrombosis at multiple sites occurring over a period of a few days to a few weeks, have been described. However, venous thrombosis as the first manifestation of an inflammatory bowel disease is extremely rare. We report the case of a 14-year-old girl presenting with ascites and marked hypertransaminasemia resulting from hepatic vein occlusion (Budd-Chiari syndrome). Despite anticoagulant therapy, in the following days she developed criteria suggestive of thrombotic storm to include cerebral vein, right atrial thrombosis, and bilateral pulmonary embolism. Thrombolytic treatment with recombinant-tissue plasminogen activator was started, with resolution of all venous thromboses and without bleeding complications. Additional examinations revealed a severely active ulcerative pancolitis, which did not respond to medical treatment and required surgery. No thrombophilia abnormality nor other risk factors for thrombosis were detected. We conclude that an underlying inflammatory state, such as ulcerative colitis, should be suspected in pediatric patients with venous thrombosis storm.

Crohn's Disease Initially Accompanied by Deep Vein Thrombosis and Ulnar Neuropathy without Metronidazole Exposure

Extraintestinal manifestations are not uncommon in Crohn's disease, and a thromboembolic event is a disastrous potential complication. Deep vein thrombosis is the most common manifestation of a thromboembolic event and typically occurs in association with active inflammatory disease. Peripheral neuropathy in Crohn's disease has rarely been reported and is considered an adverse effect of metronidazole therapy. Here, we describe a patient who was initially diagnosed with Crohn's disease complicated with deep vein thrombosis and ulnar neuropathy without metronidazole exposure. The simultaneous occurrence of these complications in the early stage of Crohn's disease has never been reported in the English literature.

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.

Thrombophilic Risk Factors in Patients With Inflammatory Bowel Disease

Background

Inflammatory bowel disease (IBD) patients have an increased risk for thromboembolism. The aim of this study was to assess the presence of thrombophilic risk factors in IBD patients and to assess the associations of these factors with disease activity.

Methods

Forty-eight patients with IBD (24 ulcerative colitis, 24 Crohn’s disease) and 40 matched healthy control individuals were enrolled. In addition to routine biochemical analysis, fasting blood samples were studied for prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, protein-C, protein-S, antithrombin III, factor VII, factor VIII, D-dimer, vitamin B₁₂, folic acid and homocysteine.

Results

Levels of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), fibrinogen, D-dimer and the number of platelets were significantly higher in patients with IBD. When compared to control group, in patients with Crohn’s disease serum homocystein levels were significantly higher (p = 0.025) while serum folic acid levels were significantly lower (p < 0.019). Levels of fibrinogen, D-dimer, protein C, factor VIII, total homocystein and the number of platelets were found to be significantly higher in Crohn’s disease patients who were in active period of the disease.

Conclusions

Thrombophilic defects are multifactorial and might be frequently seen in IBD patients. They might contribute to thrombotic complications of this disease.

Thrombosis and inflammatory bowel disease-the role of genetic risk factors

Thromboembolism is a significant cause of morbidity and mortality in patients with inflammatory bowel disease (IBD). Recent data suggest thromboembolism as a disease-specific extraintestinal manifestation of IBD, which is developed as the result of multiple interactions between acquired and genetic risk factors. There is evidence indicating an imbalance of procoagulant, anticoagulant and fibrinolytic factors predisposing in thrombosis in patients with IBD. The genetic factors that have been suggested to interfere in the thrombotic manifestations of IBD include factor V Leiden, factor II (prothrombin, G20210A), methylenetetrahydrofolate reductase gene mutation (MTHFR, 6777T), plasminogen activator inhibitor type 1 (PAI-1) gene mutation and factor XIII (val34leu). In this article we review the current data and future prospects on the role of genetic risk factors in the development of thromboembolism in IBD.

Stroke in inflammatory bowel disease: a report of two cases and review of the literature

Thrombosis is a recognised complication of inflammatory bowel disease (IBD), in particular venous thrombosis. Arterial thrombosis, especially stroke is rare. There is a paucity of information regarding stroke in IBD and its management. The authors describe two cases of stroke in patients with IBD during periods of increased disease activity. The literature regarding this devastating complication and the procoagulant state that exists in IBD are reviewed.

Stroke in inflammatory bowel disease: a report of two cases and review of the literature

Thrombosis is a recognised complication of inflammatory bowel disease (IBD), in particular venous thrombosis. Arterial thrombosis, especially stroke is rare. There is a paucity of information regarding stroke in IBD and its management. The authors describe two cases of stroke in patients with IBD during periods of increased disease activity. The literature regarding this devastating complication and the procoagulant state that exists in IBD are reviewed.

Therapy insight: Vascular complications in patients with inflammatory bowel disease

Inflammatory bowel disease (IBD) is associated with an increased risk of vascular complications. The most important of these complications are arterial and venous thromboembolism, which represent a significant cause of morbidity and mortality in IBD patients. Recent data suggest that thromboembolism is a disease-specific extraintestinal manifestation of IBD. The most common thrombotic manifestations in IBD are deep vein thrombosis of the leg and pulmonary emboli. It has been suggested that disease activity and the extent of colonic localization are correlated with the risk of developing thromboembolism. The occurrence of thrombosis in patients with IBD is partially attributed to the existing hypercoagulable state in IBD. Both coagulation and fibrinolysis are activated in patients with IBD; this is especially true for those with active disease. The most common risk factors for thrombophilia in IBD patients with venous thromboembolism are Leiden mutation in the gene encoding factor V, hyperhomocysteinemia, and antiphospholipid antibodies. The main genetic defects that have been established as risk factors for venous thrombosis are rather uncommon in IBD, but when present increase the risk of thromboembolism. Screening for coagulation defects seems justified only in IBD patients with a history of thrombosis or a family history of venous thromboembolic events. Antithrombotic treatment of IBD patients with venous thromboembolism is similar to that of thrombotic non-IBD patients.

Postoperative portal and splenic vein thrombosis in children: identification of risk factors

Postoperative portal and splenic vein thrombosis (PSVT) is a rare but potentially fatal complication after abdominal surgery. We present 2 infants with PSVT after splenectomy and total colectomy, respectively, and also provide a review of the literature. We conclude that clinicians should consider that PSVT might occur after splenectomy for a huge splenomegaly or after a total colectomy for ulcerative colitis.

Hyperhomocysteinemia in ulcerative colitis is related to folate levels

AIM: To study the prevalence and clinical significance of hyperhomocysteinemia (hHcys), an independent factor for arterial and venous thrombosis, in a group of patients with ulcerative colitis (UC).

METHODS: Fasting homocysteine (Hcys), folate, and vitamin B12 serum levels were measured in 40 UC patients and 50 healthy controls. Clinical data regarding UC were gathered.

RESULTS: Median serum Hcys levels in UC patients were similar to those in controls (12.26 µmol/L vs 12.32 µmol/L), but the prevalence of hHcys was higher in UC patients than in controls (30% vs 10%, P = 0.028). UC significantly increased the risk of hHcys (adjusted odds ratio: 4.125; 95%CI: 1.26-13.44). Multivariate regression analysis showed that male sex, folate and vitamin B12 deficiency or lower serum values were significant independent predictors of higher Hcys levels in UC patients (r² = 0.4; P<0.001).

CONCLUSION: hHcys is common in UC patients and it is related to folate and vitamin B12 deficiency or lower serum values. It would be reasonable for patients with UC to receive folate and vitamin B complex supplements as a prophylactic measure.

The emerging role of adipocytokines as inflammatory mediators in inflammatory bowel disease

Anorexia, malnutrition, altered body composition and development of mesenteric obesity are well known features of inflammatory bowel disease (IBD). Recent data suggest that dysregulation of protein secretion by white adipose tissue is involved in these manifestations of patients with IBD. Adipocytes are recently recognized as endocrine cells that secrete a variety of bioactive substances known as adipocytokines. There is evidence that adipocytokines are involved in inflammatory and metabolic pathways in human beings. Overexpression of adipocytokines such as leptin, adiponectin and resistin in mesenteric adipose tissue of operated patients with Crohn's disease has recently been reported, suggesting that mesenteric adipocytes in IBD may act as immunoregulating cells. Therefore, it could be suggested that adipocytokines play an important role in the disease pathogenesis. Moreover, modulators of mesenteric adipose function have been suggested as potential therapeutic drugs in IBD. In this review, the importance of white adipose tissue function and adipocytokines, is discussed with respect to IBD.

Association between enhanced soluble CD40 ligand and prothrombotic state in inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease is associated with an increased incidence of thromboembolic complications. The aim of this study was to investigate the role of the soluble CD40 ligand (sCD40L), which displays prothrombotic properties, in patients with ulcerative colitis (UC) and Crohn's disease (CD) in comparison with inflammatory and healthy controls.

METHODS

Plasma levels of sCD40L, prothrombin fragment 1+2 (F1+2), thrombin-antithrombin (TAT) complex and soluble P-selectin were measured in 104 inflammatory bowel disease patients (54 ulcerative colitis and 50 Crohn's disease), in 18 cases with other causes of intestinal inflammation and in 80 healthy controls using commercially available enzyme-linked immunosorbent assays. Plasma levels of sCD40L were correlated with disease activity, type, localization and treatment as well as with the measured thrombophilic parameters.

RESULTS

CD patients had significantly higher sCD40L levels than both groups of controls (CD vs HC P < 0.001; CD vs non-IBD P < 0.05). UC patients had higher but not significantly different sCD40L levels compared with the controls. Both UC and CD patients with active disease had significantly higher sCD40L levels in comparison with patients with inactive disease. Plasma levels of sCD40L were correlated with platelet count (r = 0.27, P = 0.001). They also showed a correlation with prothrombin F1+2 (r = 0.16, r = 0.03) and TAT (r = 0.15, r = 0.04) as well as with P-selectin (r = 0.19, P = 0.01).

CONCLUSIONS

The increased sCD40L plasma levels may represent, at least in some degree, a molecular link between inflammatory bowel disease and the procoagualant state.

High prevalence of combined thrombophilic abnormalities in patients with inflammatory bowel disease

INTRODUCTION

A hypercoagulable state has been recognized in patients with inflammatory bowel disease.

OBJECTIVE

The aim of this study was to determine the frequency of single and combined thrombophilic abnormalities in patients from northern Portugal with Crohn's disease or ulcerative colitis, without a history of thrombosis. METHODS A cross-sectional study involving 116 patients (42 with ulcerative colitis, 74 with Crohn's disease), and 141 randomly chosen asymptomatic blood donors was carried out. Prothrombotic variables and genetic abnormalities were assessed.

RESULTS

The prevalence of single prothrombotic abnormalities (only one alteration) in inflammatory bowel disease patients was higher than in the reference population (26% and 18%, respectively; P < 0.02). The allelic frequency of genetic polymorphisms was higher in Crohn's disease and ulcerative colitis for MTHFR C677T, ACE Del and PAI-1 4G (P < 0.001) than in the reference population. The prevalence of combined thrombophilic abnormalities (at least two alterations) in both Crohn's disease and ulcerative colitis was also higher (22% and 21%, respectively) than in the reference population (9%; P < 0.01). These differences were not related to age or gender; however, in Crohn's disease the frequency of two or more abnormalities was related to disease activity (odds ratio 3.0 [1.3-6.7]).

CONCLUSION

Higher prevalences of single and combined thrombophilic defects were found in inflammatory bowel disease patients, factors that could be involved in the disease pathogenesis.

Activated platelets are the source of elevated levels of soluble CD40 ligand in the circulation of inflammatory bowel disease patients

BACKGROUND

The CD40/CD40L system, a key regulator and amplifier of immune reactivity, is activated in inflammatory bowel disease (IBD) mucosa.

AIMS

To determine whether plasma levels of sCD40L are elevated in Crohn's disease (CD) and ulcerative colitis (UC) patients compared with normal controls, to investigate the cellular source of sCD40L, and to explore CD40L induction mechanisms.

PATIENTS

CD, UC, and normal control subjects were studied.

METHODS

The concentration of sCD40L in plasma and supernatants of freshly isolated platelets and autologous peripheral blood T cells (PBT) was measured by ELISA. Surface CD40L expression level was measured by flow cytometry in resting and thrombin activated platelets, and unstimulated and CD3/CD28 stimulated PBT before and after coculture with human intestinal microvascular endothelial cells (HIMEC).

RESULTS

Compared with normal controls, plasma sCD40L levels were significantly higher in both CD and UC patients and proportional to the extent of mucosal inflammation. Platelets from IBD patients displayed a significantly higher surface CD40L expression than those from control subjects, and released greater amounts of sCD40L than autologous PBT. Contact with IL-1beta activated HIMEC induced significant upregulation of CD40L surface expression and release by platelets.

CONCLUSIONS

Elevated levels of sCD40L in the circulation of IBD patients reflect enhanced surface expression and release of CD40L by platelets. This phenomenon translates to an increased platelet activation state apparently induced by passage through an inflamed mucosal microvascular bed, a conclusion supported by the positive correlation of plasma sCD40L levels with the extent of anatomical involvement by IBD. These results suggest that platelet-endothelial interactions critically contribute to activation of the CD40 pathway in IBD.

Intracranial sinus thrombosis in a patient with Crohn disease and factor V Leiden mutation

There is a well-known risk of thrombosis in patients with inflammatory bowel disease. Documented cases of intracranial sinus thrombosis in this setting are rare. We present the case of a 30-year-old man with Crohn disease who spontaneously developed a superior sagittal sinus thrombosis and bifrontal infarcts that resulted in death. The patient was heterozygous for factor V Leiden mutation. The literature was searched to assess the frequency of cerebral venous infarcts in inflammatory bowel disease and the role that factor V Leiden plays in thrombosis in such patients.