Reduced free protein S levels in patients with inflammatory bowel disease: prevalence, clinical relevance, and role of anti-protein S antibodies

Risk of venous thromboembolism in autoimmune diseases: A comprehensive review

Autoimmune diseases have specific pathophysiologic mechanisms leading to an increased risk of arterial and venous thrombosis. The risk of venous thromboembolism (VTE) varies according to the type and stage of the disease, and to concomitant treatments. In this review, we revise the most common autoimmune disease such as antiphospholipid syndrome, inflammatory myositis, polymyositis and dermatomyositis, rheumatoid arthritis, sarcoidosis, Sjogren syndrome, autoimmune haemolytic anaemia, systemic lupus erythematosus, systemic sclerosis, vasculitis and inflammatory bowel disease. We also provide an overview of pathophysiology responsible for the risk of VTE in each autoimmune disorder, and report current indications to anticoagulant treatment for primary and secondary prevention of VTE.

Role of Vitamin K in Intestinal Health

Intestinal diseases, such as inflammatory bowel diseases (IBDs) and colorectal cancer (CRC) generally characterized by clinical symptoms, including malabsorption, intestinal dysfunction, injury, and microbiome imbalance, as well as certain secondary intestinal disease complications, continue to be serious public health problems worldwide. The role of vitamin K (VK) on intestinal health has drawn growing interest in recent years. In addition to its role in blood coagulation and bone health, several investigations continue to explore the role of VK as an emerging novel biological compound with the potential function of improving intestinal health. This study aims to present a thorough review on the bacterial sources, intestinal absorption, uptake of VK, and VK deficiency in patients with intestinal diseases, with emphasis on the effect of VK supplementation on immunity, anti-inflammation, intestinal microbes and its metabolites, antioxidation, and coagulation, and promoting epithelial development. Besides, VK-dependent proteins (VKDPs) are another crucial mechanism for VK to exert a gastroprotection role for their functions of anti-inflammation, immunomodulation, and anti-tumorigenesis. In summary, published studies preliminarily show that VK presents a beneficial effect on intestinal health and may be used as a therapeutic drug to prevent/treat intestinal diseases, but the specific mechanism of VK in intestinal health has yet to be elucidated.

International consensus on the prevention of venous and arterial thrombotic events in patients with inflammatory bowel disease

Patients with inflammatory bowel disease (IBD) are at increased risk of thrombotic events. Therapies for IBD have the potential to modulate this risk. The aims of this Evidence-Based Guideline were to summarize available evidence and to provide practical recommendations regarding epidemiological aspects, prevention and drug-related risks of venous and arterial thrombotic events in patients with IBD. A virtual meeting took place in May 2020 involving 14 international IBD experts and 3 thrombosis experts from 12 countries. Proposed statements were voted upon in an anonymous manner. Agreement was defined as at least 75% of participants voting as 'fully agree' or 'mostly agree' with each statement. For each statement, the level of evidence was graded according to the Scottish Intercollegiate Guidelines Network (SIGN) grading system. Consensus was reached for 19 statements. Patients with IBD harbour an increased risk of venous and arterial thrombotic events. Thromboprophylaxis is indicated during hospitalization of any cause in patients with IBD. Disease activity is a modifiable risk factor in patients with IBD, and physicians should aim to achieve deep remission to reduce the risk. Exposure to steroids should be limited. Antitumour necrosis factor agents might be associated with a reduced risk of thrombotic events.

Anti-TNF-α Treatment Reduces the Baseline Procoagulant Imbalance of Patients With Inflammatory Bowel Diseases

BACKGROUND

Inflammatory bowel diseases (IBD) are characterized by an increased thrombosis risk of uncertain etiology. Coagulation derangement arising from inflammation may be a triggering factor. We hypothesized that strong inflammation inhibitors (eg, anti-tumor necrosis factor-α drugs) may affect coagulation.

METHODS

Forty patients with IBD were compared with 57 control patients for coagulation factors and endogenous thrombin potential (ETP), the latter being the most sensitive marker of in vivo pro- and anticoagulation balance. We measured ETP in the presence and absence of thrombomodulin (the physiologic protein C [PC] activator). Coagulation at different timepoints was also assessed for 28 of these patients during infliximab treatment.

RESULTS

The median ETP (nM thrombin × minutes) and range (minimum-maximum) were each higher in patients at baseline than in control patients in both the absence (2120 [1611-3041] vs 1865 [1270-2337]) and the presence (1453 [464-2522] vs 831 [104-1741]) of thrombomodulin. The ETP ratio (with/without thrombomodulin) was high at baseline (0.73 [0.21-0.90] vs 0.45 [0.07-0.85]). The ETP and ETP ratio declined during treatment and were significantly lower at the end than at baseline. Factor (F) VIII and fibrinogen, which were high at baseline, decreased during treatment and at the end were significantly lower than at baseline. The FVIII/PC ratio, which was high in patients at baseline, declined during treatment and at the end was lower than at baseline. C-reactive protein recorded at the end of treatment was lower than at baseline.

CONCLUSIONS

Patients with IBD have a procoagulant imbalance as shown by increased ETP at baseline. The ETP decreases during treatment with infliximab, which is related to decreased FVIII and FVIII/PC ratio. This effect is also related to the improvement of inflammation as shown by decreased fibrinogen and C-reactive protein.

Venous and arterial thromboembolism in patients with inflammatory bowel diseases

The risk of thromboembolism (TE) is increased in patients with inflammatory bowel disease (IBD), mainly due to an increased risk of venous TE (VTE). The risk of arterial TE (ATE) is less pronounced, but an increased risk of cardiovascular diseases needs to be addressed in IBD patients. IBD predisposes to arterial and venous thrombosis through similar prothrombotic mechanisms, including triggering activation of coagulation, in part mediated by impairment of the intestinal barrier and released bacterial components. VTE in IBD has clinical specificities, i.e., an earlier first episode in life, high rates during both active and remission stages, higher recurrence rates, and poor prognosis. The increased likelihood of VTE in IBD patients may be related to surgery, the use of medications such as corticosteroids or tofacitinib, whereas infliximab is antithrombotic. Long-term complications of VTE can include post-thrombotic syndrome and high recurrence rate during post-hospital discharge. A global clot lysis assay may be useful in identifying patients with IBD who are at risk for TE. Many VTEs occur in IBD outpatients; therefore, outpatient prophylaxis in high-risk patients is recommended. It is crucial to continue focusing on prevention and adequate treatment of VTE in patients with IBD.

Perioperative parenteral fish oil supplementation improves postoperative coagulation function and outcomes in patients undergoing colectomy for ulcerative colitis

OBJECTIVE

Ulcerative colitis (UC) is an independent risk factor for thromboembolism, especially during the perioperative period. This study aimed to determine the effects of perioperative parenteral nutrition (PN) supplemented with fish oil (FO) on coagulation function and postoperative outcomes in patients with UC.

METHODS

This retrospective cohort included 92 consecutive patients who underwent colectomy for UC. Postoperative coagulation indices and outcomes, including thromboelastography (TEG) findings and comprehensive complication index (CCI), were compared. The relative change in serum D-dimer (ΔD-dimer) levels and maximal amplitude (ΔMA) on TEG were also determined.

RESULTS

Patients receiving PN supplemented with FO (n = 48) had lower D-dimer (P = .036) levels on postoperative day (POD) 5 and a higher MA (P < 0.001) on POD 1 than those who did not receive it (n = 44). A lower ΔD-dimer level (P = .048) and ΔMA (P < 0.001) were also observed in patients receiving FO. The incidence of major postoperative complications (6.3 vs 22.7%; P = .017) and CCI (20.9 vs 23.4%; P = .044) were significantly lower in patients receiving FO. In multivariate analysis, FO (odds ratio, 0.231; 95% confidence interval, 0.055-0.971; P = .046) was a positive protector of major postoperative complications.

CONCLUSION

Perioperative PN supplemented with FO improved coagulation function and reduced major postoperative complications in patients with UC requiring colectomy. These results may provide cues in formulating management strategies for preventing thromboembolisms and postoperative complications in patients with UC.

Spontaneous skin necrosis revealing protein S deficiency in Crohn's disease

Inflammatory bowel diseases are associated with a state of hypercoagulability secondary to several mechanisms, protein S deficiency being one of these. It can be revealed by spontaneous skin necrosis in children. This condition is rare in adults with Crohn's disease. We are reporting a case of a 35-year-old woman with active Crohn's disease who presented a protein S deficiency responsible for an extensive spontaneous skin necrosis. The evolution was favourable after vascular filling, curative anticoagulation, antibiotic therapy, as well as a high-dose of corticosteroid therapy. We are reporting this case in order to emphasize the importance of considering skin necrosis as a possible cutaneous manifestation of inflammatory bowel diseases.

Budd-Chiari syndrome: a rare and life-threatening complication of Crohn's disease

Budd-Chiari syndrome (BCS) is characterised by obstruction of hepatic venous outflow and may be triggered by the prothrombotic state associated with inflammatory bowel disease (IBD). We reported a case of Crohn's disease (CD) that presented with anasarca, ascites, symptomatic hepatomegaly, elevated liver enzymes, increased prothrombin time and low albumin. Oesophagogastroduodenoscopy and colonoscopy confirmed active CD. Abdominal CT showed hepatic vein thrombosis. Liver biopsy revealed severe perivenular sinusoidal dilation with areas of hepatocyte dropout, bands of hepatocyte atrophy and centrizonal fibrosis, suggestive of BCS. The patient was treated with steroids for CD and systemic anticoagulants for BCS. His liver function and enzymes normalised, and he reported symptomatic improvement. The precise mechanism responsible for increased hypercoagulability in IBD remains unclear. Early recognition and treatment for possible thrombotic complications of CD is critical to prevent potentially fatal events like pulmonary embolism or liver failure.

Prevalence, significance and predictive value of antiphospholipid antibodies in Crohn’s disease

AIM: To assess the prevalence and stability of different antiphospholipid antibodies (APLAs) and their association with disease phenotype and progression in inflammatory bowel diseases (IBD) patients.

METHODS: About 458 consecutive patients [Crohn’s disease (CD): 271 and ulcerative colitis (UC): 187] were enrolled into a follow-up cohort study in a tertiary IBD referral center in Hungary. Detailed clinical phenotypes were determined at enrollment by reviewing the patients’ medical charts. Disease activity, medical treatment and data about evolvement of complications or surgical interventions were determined prospectively during the follow-up. Disease course (development f complicated disease phenotype and need for surgery), occurrence of thrombotic events, actual state of disease activity according to clinical, laboratory and endoscopic scores and accurate treatment regime were recorded during the follow-up, (median, 57.4 and 61.6 mo for CD and UC). Sera of IBD patients and 103 healthy controls (HC) were tested on individual anti-β2-Glycoprotein-I (anti-β2-GPI IgA/M/G), anti-cardiolipin (ACA IgA/M/G) and anti-phosphatidylserine/prothrombin (anti-PS/PT IgA/M/G) antibodies and also anti-Saccharomyces cerevisiae antibodies (ASCA IgA/G) by enzyme-linked immunosorbent assay (ELISA). In a subgroup of CD (n = 198) and UC patients (n = 103), obtaining consecutive samples over various arbitrary time-points during the disease course, we evaluated the intraindividual stability of the APLA status. Additionally, we provide an overview of studies, performed so far, in which significance of APLAs in IBD were assessed.

RESULTS: Patients with CD had significantly higher prevalence of both ACA (23.4%) and anti-PS/PT (20.4%) antibodies than UC (4.8%, P < 0.0001 and 10.2%, P = 0.004) and HC (2.9%, P < 0.0001 and 15.5%, P = NS). No difference was found for the prevalence of anti-β2-GPI between different groups (7.2%-9.7%). In CD, no association was found between APLA and ASCA status of the patients. Occurrence of anti-β2-GPI, ACA and anti-PS/PT was not different between the group of patients with active vs inactive disease state according to appropriate clinical, laboratory and endoscopic scores in CD as well as in UC patients. All subtypes of anti-β2-GPI and ACA IgM status were found to be very stable over time, in contrast ACA IgG and even more ACA IgA status showed significant intraindividual changes. Changes in antibody status were more remarkable in CD than UC (ACA IgA: 49.9% vs 23.3% and ACA IgG: 21.2% vs 5.8%). Interestingly, 59.1% and 30.1% of CD patients who received anti-TNF therapy showed significant negative to positive changes in ACA IgA and IgG antibody status respectively. APLA status was not associated with the clinical phenotype at diagnosis or during follow-up, medical therapy, or thrombotic events and it was not associated with the probability of developing complicated disease phenotype or surgery in a Kaplan-Meier analysis.

CONCLUSION: The present study demonstrated enhanced formation of APLAs in CD patients. However, presence of different APLAs were not associated with the clinical phenotype or disease course.

Antiphospholipid Antibodies and Procoagulant Profile in Tunisians With Inflammatory Bowel Diseases

The hypercoagulable state accompanying inflammatory bowel diseases (IBDs) is still poorly understood. The aim of this study was to assess antiphospholipid antibodies (APAs) and a large panel of inherited and acquired thrombotic markers simultaneously in a sample of Tunisian patients with IBD. In total, 89 consecutive patients with IBD (mean age 38 ± 15 years; 48 with Crohn disease and 41 with ulcerative colitis) and 129 controls were prospectively evaluated for immunoglobulin (Ig) G, IgM, and IgA antibodies against cardiolipin (aCL), β2glycoprotein I (aβ2GPI), and prothrombin (aPT); IgG and IgM antibodies against phosphatidic acid (aPA), phosphatidylinositol (aPI), and annexin V (aAnnV); lupus anticoagulant (LA); coagulation factors; natural inhibitors; and thrombotic genetic polymorphisms. Levels of fibrinogen, factors II, V, and VIII and von Willebrand factor, antithrombin, and protein C were significantly higher in patients with IBD than in controls (P < .05 for all comparisons). At least 1 APA subset was detected in 54 patients. The frequencies of antibodies against anionic phospholipids-aCL, aPI, and aPA-in patients with IBD were 15.9%, 21.3%, and 14.6%, respectively. The frequencies of antiphospholipid cofactor antibodies were 39.8% for aβ2GPI and 15.7% for both aAnnV and aPT. Isolated aβ2GPI IgA was detected in 22 patients, and 12 (13.5%) patients had LA. The IgA aβ2GPI antibodies were frequently detected in Tunisian patients with IBD. These results are of potential diagnostic, prognostic, and therapeutic interest.

Thrombosis in inflammatory bowel diseases: what's the link?

Inflammatory bowel disease affects more than 2 million people in Europe, with almost 20% of patients being diagnosed in pediatric age. Patients with inflammatory bowel disease are at increased risk of thromboembolic complications which may affect patients’ morbidity and mortality. The risk of the most common thromboembolic events, such as deep venous thrombosis and pulmonary embolism, are estimated to be three-fold increased compared to controls, but many other districts can be affected. Moreover, patients with ulcerative colitis and Crohn’s disease experience thromboembolic events at a younger age compared to general population. Many factors have been investigated as determinants of the pro-thrombotic tendency such as acquired risk factors or genetic and immune abnormalities, but a unique cause has not been found. Many efforts have been focused on the study of abnormalities in the coagulation cascade, its natural inhibitors and the fibrinolytic system components and both quantitative and qualitative alterations have been demonstrated. Recently the role of platelets and microvascular endothelium has been reviewed, as the possible link between the inflammatory and hemostatic process.

Tyro3, Axl, and Mertk receptor signaling in inflammatory bowel disease and colitis-associated cancer

Three receptor tyrosine kinases, Tyro3, Axl, and Mertk (TAM) and their ligands Gas6 and Protein S, have emerged as potent negative regulators of innate immune responses. A number of studies using genetic ablation of TAM loci in mice have elucidated the mechanism of TAM engagement and function during the immune response and removal of apoptotic cells. Following phagocytosis of apoptotic cells or the induction of T-cell dependent adaptive immune responses, ligand-induced TAM signaling dampens proinflammatory cytokine production and thus prevents exaggerated or prolonged inflammation. It is believed that the TAM pathway may play an important role in the pathogenesis of inflammatory bowel disease. Suppression of inflammation and removal of apoptotic cells followed by tissue repair are essential processes for disease remission and the successful management of inflammatory bowel disease. In light of the key role of TAMs in controlling inflammatory responses, here, we review the recent advances on TAM research vis-à-vis the resolution of intestinal inflammation. Targeted activation of TAM receptor tyrosine kinases may represent a potent therapeutic opportunity in inflammatory bowel disease.

Consensus statements on the risk, prevention, and treatment of venous thromboembolism in inflammatory bowel disease: Canadian Association of Gastroenterology

BACKGROUND & AIMS

Guidelines for the management of venous thromboembolism (VTE) from the American College of Chest Physicians do not address patients with inflammatory bowel disease (IBD), a group with a high risk of both VTE and gastrointestinal bleeding. We present recommendations for the prevention and treatment of VTE in patients with IBD.

METHODS

A systematic literature search was performed to identify studies on VTE in IBD. The quality of evidence and strength of recommendations were rated according to the Grading of Recommendation Assessment, Development, and Evaluation (GRADE) approach. Statements were developed through an iterative online platform, then finalized and voted on by a working group of adult and pediatric gastroenterologists and thrombosis specialists.

RESULTS

IBD patients have an approximately 3-fold higher risk of VTE compared with individuals without IBD, and disease flares further increase this risk. Anticoagulant thromboprophylaxis is recommended for IBD patients who are hospitalized with IBD flares without active bleeding and is suggested when bleeding is nonsevere. Anticoagulant thromboprophylaxis is suggested during moderate-severe IBD flares in outpatients with a history of VTE provoked by an IBD flare or an unprovoked VTE, but not otherwise. The recommended duration of anticoagulation after a first VTE is based on the presence of provoking factors. Specific suggestions are made for the prevention and treatment of VTE in pediatric and pregnant IBD patients.

CONCLUSIONS

Using the American College of Chest Physicians' guidelines as a foundation, we have integrated evidence from IBD studies to develop specific recommendations for the management of VTE in this high-risk population.

Assessment of anti-prothrombin antibodies in thrombosis complicating inflammatory bowel diseases

PURPOSE

In inflammatory bowel diseases (IBD), risk of thrombosis and production of antibodies are increased. In autoimmune and inflammatory disorders, a role of anti-prothrombin (aPT) antibodies in developing thrombosis has been hypothesised. The aim of the study is to evaluate the prevalence of aPT antibodies in IBD patients, with and without thrombosis.

METHODS

Thirty-three IBD patients with thrombosis, 33 IBD patients without thrombosis matched for sex, age, diagnosis and disease activity and 66 sex- and age-matched healthy controls were enrolled. Thrombosis was considered recent when blood sample was obtained within 3 months from the event.

RESULTS

Prevalence of aPT antibodies in thrombotic IBD patients (3/33, 9.1 %), non-thrombotic IBD patients (4/33, 12.1 %) and in healthy subjects (3/66, 4.5 %) did not result significantly different (p = 0.377). The prevalence of aPT antibodies was more frequent in ulcerative colitis (6/32, 18.7 %) than in Crohn's disease (1/34, 2.9 %) and healthy controls (p = 0.022). Among thrombotic IBD patients, the prevalence of aPT antibodies was higher in those with recent (2/9, 22.2 %) than in those with previous thrombosis (1/24, 4.2 %) (p = 0.103). All thrombotic IBD patients with aPT antibodies were affected by ulcerative colitis with previous history of deep venous thrombosis.

CONCLUSIONS

aPT antibodies do not appear to play a relevant role in thrombosis complicating IBD course. A possible association in ulcerative colitis patients with DVT could not be excluded.

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.

Venous thrombotic events in hospitalized children and adolescents with inflammatory bowel disease

BACKGROUND

Adults with inflammatory bowel disease (IBD) have an increased risk of venous thrombotic events (TEs). We sought to evaluate the risk for TE in children and adolescents with IBD using a large population database.

METHODS

The triennial Healthcare Cost and Utilization Project Kids' Inpatient Database was used in a retrospective cohort study of hospitalized children in the United States across 1997, 2000, 2003, 2006, and 2009. Billing codes were used to identify discharges with Crohn disease, ulcerative colitis, pulmonary embolism, deep vein thrombosis, thrombophlebitis, thrombosis of intracranial venous sinus, Budd-Chiari syndrome, and portal vein thrombosis. A logistic regression model was fitted to quantify the increased risk of TE in children with IBD, while adjusting for other risk factors of thrombosis.

RESULTS

The total weighted number of pediatric discharges was 7,448,292, and 68,394 (0.92%) were identified with IBD. The incidence of any TE in a hospitalized child or adolescent with IBD was 117.9/10,000 with a relative risk (95% confidence interval) of 2.36 (2.15-2.58). The adjusted odds ratio for any TE in a patient with IBD without surgery was 1.22 (1.08-1.36). Risk factors for TE among patients with IBD include older age, central venous catheter, parenteral nutrition, and an identified hypercoagulable condition. There is an increasing trend of TE in both the IBD and non-IBD patients.

CONCLUSIONS

Hospitalized children and adolescents with IBD are at increased risk for TE. Conservative methods of TE prevention including hydration, mobilization, or pneumatic devices should be considered in hospitalized patients with IBD.

Budd-Chiari syndrome in a patient with ulcerative colitis and no inherited coagulopathy

We report a case of 27 year old female patient who was admitted to the hospital with an acute flare up of ulcerative colitis. The patient presented with complaints of persistent abdominal pain and bloody diarrhea despite aggressive therapy for her ulcerative colitis. A CT scan of the abdomen on admission revealed hepatic vein thrombosis, suggesting a diagnosis of Budd-Chiari syndrome. Significantly, an associated thrombosis of the inferior mesenteric vein was also detected. Based on imaging data and clinical assessment, the patient was started on anticoagulation therapy and an extensive work-up for hypercoagulability was initiated. Up to the time of publication, no significant findings suggesting this patient has an underlying coagulation disorder have been found. Based on our search of PUBMED, this report is one of only five reported adult cases of Budd-Chiari Syndrome associated with ulcerative colitis in the English literature in living patients without evidence of a co-existing coagulation disorder. This case highlights the potential for thrombosis at unusual sites in ulcerative colitis patients even in the absence of classical coagulation abnormalities. In addition to the case presented, we provide a brief review of previously reported cases of Budd-Chiari Syndrome occurring in patients with inflammatory bowel disease.

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. Crohn's 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.

Antibodies to tissue-type plasminogen activator (t-PA) in patients with inflammatory bowel disease: high prevalence, interactions with functional domains of t-PA and possible implications in thrombosis

BACKGROUND

Patients with inflammatory bowel disease (IBD) have an increased prevalence of thromboembolic events. The pathogenetic mechanisms of these events include reduced fibrinolysis, which may be caused by antibodies to tissue-type plasminogen activator (t-PA).

OBJECTIVES

To evaluate anti-t-PA antibodies in patients with IBD, considering clinical, biochemical and functional characteristics.

PATIENTS AND METHODS

We immunoenzymatically measured anti-t-PA antibodies in plasma from 97 consecutive IBD patients and 97 age- and sex-matched healthy controls. We also assessed the antibody interactions with different epitopes of t-PA, the antibody inhibition on t-PA activity and the correlations with clinical features and other serum antibodies.

RESULTS

IBD patients had higher median anti-t-PA antibody levels (5.4 U mL(-1) vs. 4.0 U mL(-1); P < 0.0001): 18 patients were above the 95th percentile of the controls (OR 5.3; 95% CI 1.7-16.3; P < 0.003), and the six with a history of thrombosis tended to have high levels (6.9 U mL(-1)). Anti-t-PA antibody levels did not correlate with IBD type, activity, location or treatment, or with age, sex, acute-phase reactants or other antibodies. The anti-t-PA antibodies were frequently IgG1 and bound t-PA in fluid phase; they recognized the catalytic domain in 10 patients and the kringle-2 domain in six. The IgG fraction from the three patients with the highest anti-t-PA levels slightly reduced t-PA activity in vitro.

CONCLUSIONS

The prevalence of anti-t-PA antibodies is high in IBD patients. By binding the catalytic or kringle-2 domains of t-PA, these antibodies could lead to hypofibrinolysis and contribute to the prothrombotic state of IBD.

Systemic thromboembolism in inflammatory bowel disease: mechanisms and clinical applications

Systemic thromboembolism is an extraintestinal manifestation of inflammatory bowel disease (IBD), and an important cause of patient morbidity and mortality. The underlying basis for the hypercoagulable state in IBD is complex, and involves altered activity of all three components that govern hemostasis: platelets, fibrinolysis, and the coagulation cascade. Currently, there are no distinct guidelines for treating or preventing thromboembolic (TE) events in IBD patients compared with the general population. However, the prothrombotic state in IBD stems, at least in part, from several modifiable factors, such as hyperhomocysteinemia and an active inflammatory state. In this review we summarize the mechanisms that favor thrombosis in IBD, and the principles that need to be applied for the primary and secondary prevention of TE in this selected group of patients.

Thrombosis and inflammatory bowel disease

Interaction between thrombosis and inflammation is increasingly recognized. With this, interest has arisen in the role of thrombosis in inflammatory conditions, including the inflammatory bowel diseases. Although the association between active inflammatory bowel disease and thromboembolic complications has long been known, there has been a resurgence in research into the role of thrombosis and the hemostatic system in the pathogenesis of both ulcerative colitis and Crohn's disease. Here we review the increased frequency of thromboembolic complications occurring in patients with inflammatory bowel disease; whether thrombosis might play a part in the initiation and maintenance of inflammation in inflammatory bowel disease; abnormalities of the coagulation system found in patients with inflammatory bowel disease; platelet dysfunction in inflammatory bowel disease; the mechanisms by which hemostatic processes might be proinflammatory in inflammatory bowel disease; and how these interactions might impact not only on the prevention of complications, but also on the treatment of the underlying inflammation in inflammatory bowel disease.

Expression of endothelial protein C receptor and thrombomodulin in the intestinal tissue of patients with inflammatory bowel disease

OBJECTIVE

Inflammatory bowel diseases are characterized by disorders of immunity, thrombosis of large vessels, and microthrombosis of mucosal vessels. The expression of endothelial protein C receptor (EPCR) and thrombomodulin-two receptors of the protein C pathway involved in thrombin scavenging and inflammation-was studied in intestinal resection specimens or mucosal biopsies from patients with inflammatory bowel disease and from controls. The soluble forms of the receptors in plasma were measured.

DATA SOURCE

This study involved patients from two large university hospitals. After surgery or biopsy, tissue samples were either frozen or fixed in formalin and embedded in paraffin. Sections for immunohistochemistry examination were cut and tested with the specific antibodies to EPCR and thrombomodulin. RNA was extracted from frozen tissue for amplification via reverse-transcriptase polymerase chain reaction. Normal intestinal and diverticulitis tissue was used as a control. Resection samples from 36 patients with ulcerative colitis, 38 with Crohn's disease, 38 with colonic cancer, and 32 with diverticulitis were studied by immunohistochemistry, and frozen sections from the same patients were studied by immunofluorescence. Twelve biopsy specimens of adjacent intestinal areas from six patients with inflammatory bowel disease were included in the study for reverse-transcriptase polymerase chain reaction. Soluble receptors were measured in the plasma of 52 inflammatory bowel disease patients and 52 controls.

DATA SUMMARY

EPCR and thrombomodulin were expressed on the mucosal endothelium of controls, and the intensity of the signal decreased in inflammatory bowel disease patients. EPCR was expressed by dendritic-like cells in controls, which also stained positive for CD21. The EPCR/CD21 dendritic-like cells were not as commonly observed in sections from ulcerative colitis patients as they were in sections from control patients (12.0 +/- 3.6 cells per high-power field vs. 23.8 +/- 10.4 cells per high-power field, p =.03), and this decrease was less evident in sections from Crohn's disease patients. Levels of messenger RNA for EPCR paralleled protein expression. Soluble thrombomodulin and EPCR levels were both higher in patients than in controls: 41.5 vs. 26.0 ng/mL (p <.0001) and 141 vs. 130 ng/mL (p <.05), respectively.

CONCLUSIONS

EPCR expression on dendritic-like cells that bear the key complement receptor CD21 suggests a role for EPCR in innate immunity. The reduced expression of thrombomodulin and EPCR in the mucosal vessels in inflammatory bowel disease impairs protein C activation, favoring microthrombosis.

Val34Leu factor XIII polymorphism in Italian patients with inflammatory bowel disease

BACKGROUND

Coagulation Factor XIII is implicated in fibrin stabilization and wound healing. Plasma levels of Factor XIII are reduced in inflammatory bowel disease patients; recently, a valine 34 to leucine polymorphism of the Factor XIII-A subunit gene with a defined protective effect against thrombosis and as yet undetermined effect on wound healing has been described.

AIM

To evaluate Val34Leu Factor XIII polymorphism distribution and to find possible correlations with clinical features in Italian inflammatory bowel disease patients.

STUDY POPULATION

A total of 152 inflammatory bowel disease patients, 90 with ulcerative colitis and 62 with Crohn's disease and 130 healthy volunteers were studied.

METHODS

Val34Leu polymorphism was detected by RFLP with BsaH I. Statistical analysis was performed by means of Fisher exact test.

RESULTS

In inflammatory bowel disease, 57.2% of patients showed the wild type status, 37.5% were heterozygous and 5.3% were homozygous for the 34Leu allele; the frequency of the mutated allele was 24.0%. In controls, 66.1% of subjects showed the wild type status, 28.5% were heterozygous and 5.4% were homozygous for the 34Leu allele; the frequency of the mutated allele was 19.7%. There was no difference in genotype distribution and prevalence of the mutated allele between inflammatory bowel disease patients and controls.

CONCLUSIONS

The present data do not show any differences in Val34Leu Factor XIII polymorphism distribution between inflammatory bowel disease patients and controls. The prothrombotic state described in inflammatory bowel disease patients does not depend on an altered distribution of Val34Leu Factor XIII polymorphism.