Randomized, placebo-controlled trial of low molecular weight heparin in active ulcerative colitis

Venous thromboembolism in chronic gastrointestinal disorders

INTRODUCTION

Chronic gastrointestinal disorders (including autoimmune gastritis, celiac disease, inflammatory bowel disease, and diverticular disease) are highly prevalent disorders, that may be associated with unpredictable, life-threatening complications, such as thromboembolic events. Venous thromboembolism (VTE) is one of the major causes of morbidity and mortality worldwide. Several conditions, including cancer, major trauma, surgery, prolonged immobilization, are well-established risk factors for VTE. Over the past decade, chronic inflammation has also been identified as an independent risk factor for VTE due to the prothrombotic effects of inflammatory cytokines and oxidative stress on the coagulation cascade. Other several mechanisms were shown to be associated with a higher incidence of VTE in patients with gastrointestinal disorders.

AREAS COVERED

We critically discuss the latest insights into the mechanisms responsible for thromboembolic manifestations in chronic gastrointestinal disorders, also focusing on the recognition of risk factors and treatment.

EXPERT OPINION

The occurrence of thrombotic complications is underestimated in patients with chronic gastrointestinal disorders. Identifying potential risk factors and concomitant predisposing conditions and to prevent VTE and guide treatment require a multidisciplinary approach, and this is critically important for clinicians, in order to provide the best care for such patients.

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.

Histologic Healing Rates of Medical Therapies for Ulcerative Colitis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVES

Histologic remission is a potentially valuable means of assessing disease activity and treatment response in ulcerative colitis (UC). However, the efficacy of existing therapies to achieve this outcome is unclear. We performed a systematic review and meta-analysis of histologic outcomes in UC randomized controlled trials and examined the relationship between histologic and endoscopic outcomes.

METHODS

MEDLINE, EMBASE, CENTRAL, and the Cochrane IBD Register were searched for randomized controlled trials of aminosalicylates, corticosteroids, immunosuppressives, biologics, and small molecules. Histologic and endoscopic remission and response data were independently extracted and pooled using binomial-normal random-effect or fixed-effect models. Pooled efficacy estimates were calculated as risk ratios (RRs) using the Mantel-Haenszel method. Univariable and multivariable random-effect meta-regression models examined factors associated with histologic remission.

RESULTS

Seventy-four studies (68 induction and 7 maintenance) were identified. Topical aminosalicylate enemas [37.2%, 95% confidence interval (CI), 29.0-46.3] and suppositories (44.9%, 95% CI, 28.9-62.3) had the highest induction of histologic remission rates. Aminosalicylate enemas (RR = 4.14, 95% CI, 2.35-7.31), aminosalicylate suppositories (RR = 3.94, 95% CI, 1.26-12.32), and budesonide multimatrix (RR = 1.47, 95% CI 1.08-1.99) had higher histologic remission rates than placebo. Data were lacking for biologics and immunosuppressives. The pooled histologic remission rate for placebo in induction studies was 10.4% (95% CI, 7.1-15.2). Histologic and endoscopic remission correlated strongly (r = 0.66; 95% CI, 0.50-0.78). In multivariate analysis of placebo-arm data, less severe clinical disease activity and corticosteroid use were associated with higher histologic remission rates. Similarly, mild clinical disease activity was associated with higher histologic remission rates when active-arm data were analyzed.

CONCLUSIONS

Histologic remission rates for current UC treatments ranged from 15.0% to 44.9% according to drug class and patient population with the highest rates observed for topical aminosalicylates. Placebo remission rates were low with relatively narrow CIs. These data provide benchmarks to inform future trial design. Histologic remission is a potential treatment target in clinical practice.

Therapeutic Potential of Enoxaparin in Lichen Planus: Exploring Reasons for Inconsistent Reports

Lichen planus (LP) is an uncommon mucocutaneous inflammatory condition, that is immunologically mediated, typically pruritic and often recurs. The currently advocated therapies are either not highly effective or associated with severe side effects. Enoxaparin, a widely used anticoagulant, is composed of both anticoagulant and non-anticoagulant fragments. Enoxaparin is reported to have anti-inflammatory properties and it was found to be effective in LP. However, the results from clinical studies have varied substantially and, therefore, the clinical role of enoxaparin in LP remains uncertain. This review focuses on potential reasons for the reported inconsistent outcomes, as well as proposing solutions; these include identifying batch-to-batch inconsistency in the composition of enoxaparin. The potential therapeutic value of enoxaparin in LP must be explored using well-designed clinical trials, combined with experimental studies that focus on identifying the anti-inflammatory fragments of enoxaparin and elucidating the mechanism of action of these non-anticoagulant fragments.

Thrombotic mechanism and anticoagulant therapy in inflammatory bowel disease patients

Thromboembolism (TE) in inflammatory bowel disease (IBD) is an increasingly noted extra-intestinal manifestation with high morbidity (about 1%-8%), and the incidence rate can reach 41% by mucosal biopsy. Although TE is a life-threatening complication of IBD, this complication is often overlooked. To date, the mechanism behind this prothrombotic state encountered in IBD patients is not fully understood, and it is multifactorial and related to the inflammatory state. In this review, we provide an overview of the current understanding of thrombotic mechanism and anticoagulant therapy in IBD. While controlling the activity of the disease with appropriate therapy, thromboembolism prophylaxis should be considered.

Managing acute severe ulcerative colitis in the hosptialised setting

Ulcerative colitis affects approximately 146 000 people in the UK and is the most common form of inflammatory bowel disease. The majority of patients will have uncomplicated disease, but around 1 in 10 patients will develop acute severe colitis. Despite modern medical management, colectomy rates of 27% and mortality rates of 1% are still reported. Good supportive care and intravenous corticosteroids remain the mainstay of treatment, but up to one-third of patents will not respond. The Travis criteria allow early recognition of those patients failing to improve by day 3, allowing timely planning of medical rescue therapy or surgery. Rescue therapy with either infliximab or ciclosporin appears equally efficacious. Patients naive to thiopurines seem to have better colectomy-free survival rates following rescue therapy than those previously exposed. We review the published evidence behind the conventional management of acute severe ulcerative colitis.

Heparins in ulcerative colitis: proposed mechanisms of action and potential reasons for inconsistent clinical outcomes

Current drug therapies for ulcerative colitis (UC) are not completely effective in managing moderate-to-severe UC and approximately 20% of patients with severe UC require surgical interventions. Heparins, polydisperse mixtures of non-anticoagulant and anticoagulant oligosaccharides, are widely used as anticoagulants. However, heparins are also reported to have anti-inflammatory properties. Unfractionated heparin was initially used in patients with UC for the treatment of rectal microthrombi. Surprisingly, it was found to be effective in reducing UC-associated symptoms. Since then, several pre-clinical and clinical studies have reported promising outcomes of heparins in UC. In contrast, some controlled clinical trials demonstrated no or only limited benefits, thus the potential of heparins for the treatment of UC remains uncertain. This review discusses potential mechanisms of action of heparins, as well as proposed reasons for their contradictory clinical effectiveness in the treatment of UC.

Unfractionated or low-molecular weight heparin for induction of remission in ulcerative colitis

BACKGROUND

There are a limited number of treatment options for patients with ulcerative colitis (UC). An increased risk of thrombosis in UC coupled with an observation that UC patients being treated with anticoagulant therapy for thrombotic events had an improvement in their bowel symptoms led to trials examining the use of unfractionated heparin (UFH) and low molecular weight heparins (LMWH) in patients with active UC.

OBJECTIVES

To review randomized trials examining the efficacy of unfractionated heparin (UFH) or low molecular weight heparins (LMWH) for remission induction in patients with ulcerative colitis.

SEARCH METHODS

We searched MEDLINE, EMBASE, CENTRAL, and the Cochrane IBD/FBD group specialized trials register up to June 2014. We also searched review papers on ulcerative colitis and references from identified papers in an effort to identify additional randomized trials studying UFH or LMWH use in patients with ulcerative colitis. We searched abstracts from major gastroenterological meetings to identify research published in abstract form.

SELECTION CRITERIA

Randomized controlled trials comparing UFH or LMWH to placebo or a control therapy for induction of remission in ulcerative colitis were included. Studies published in abstract form only were included if the authors could be contacted for further information.

DATA COLLECTION AND ANALYSIS

A data extraction form was developed and used to extract data from included studies. Two authors independently extracted data. Any disagreements were resolved by consensus. The Cochrane Risk of Bias tool was used to assess study quality. Data were analyzed on an intention-to-treat basis. The primary outcome was induction of remission, as defined by the studies. Secondary outcomes measures included: endoscopic remission as defined by the authors; clinical, histological or endoscopic improvement as defined by the authors; the occurrence of adverse events; the occurrence of bleeding; and improvements in quality of life as measured by a validated instrument. We calculated the risk ratio (RR) and corresponding 95% confidence interval for dichotomous outcomes. Data were combined for analysis if they assessed the same treatments (UFH or LMWH versus placebo or other therapy). The overall quality of the evidence supporting the outcomes was evaluated using the GRADE criteria.

MAIN RESULTS

Five studies were eligible for inclusion (329 patients). Three studies (270 patients) compared low molecular weight heparin to placebo, one study (34 patients) compared LMWH in addition to standard therapy, and one study (25 patients) compared UFH to corticosteroids. The study comparing UFH to corticosteroids was rated at high risk of bias due to a single-blind design. The study that compared the addition of LMWH to standard therapy to standard therapy alone was rated at high risk of bias due to open-label design. The other three studies were rated as low risk of bias. LMWH administered subcutaneously showed no benefit over placebo for any outcome, including clinical remission (very low quality of evidence), and clinical, endoscopic, or histological improvement. High dose LMWH administered via an extended colon-release tablet demonstrated benefit over placebo for clinical remission (RR 1.39; 95% CI 1.09 to 1.77 ; P = 0.008; very low quality of evidence), clinical improvement (RR 1.28; 95% CI 1.06 to 1.55; P = 0.01; very low quality of evidence), and endoscopic improvement (RR 1.21; 95% CI 1.00 to 1.47 ; P = 0.05) but not endoscopic remission or histologic improvement. LMWH was not beneficial when added to standard therapy for clinical remission, clinical improvement, endoscopic remission or endoscopic improvement. LMWH was well-tolerated but provided no significant benefit for quality of life. One study examining UFH versus corticosteroids for the treatment of severe UC demonstrated the inferiority of UFH for clinical improvement. More patients assigned to UFH had rectal hemorrhage as an adverse event.

AUTHORS' CONCLUSIONS

There is evidence to suggest that LMWH may be effective for the treatment of active UC. When administered by extended colon-release tablets, LMWH was more effective than placebo for treating outpatients with mild to moderate disease. This benefit needs to be confirmed by further randomized controlled studies. The same benefits were not seen when LMWH was administered subcutaneously at lower doses. There is no evidence to support the use of UFH for the treatment of active UC. A further trial of UFH in patients with mild disease may also be justified. Any benefit found would need to be weighed against a possible increased risk of rectal bleeding in patients with active UC.

Orally Administered Enoxaparin Ameliorates Acute Colitis by Reducing Macrophage-Associated Inflammatory Responses

Inflammatory bowel diseases, such as ulcerative colitis, cause significant morbidity and decreased quality of life. The currently available treatments are not effective in all patients, can be expensive and have potential to cause severe side effects. This prompts the need for new treatment modalities. Enoxaparin, a widely used antithrombotic agent, is reported to possess anti-inflammatory properties and therefore we evaluated its therapeutic potential in a mouse model of colitis. Acute colitis was induced in male C57BL/6 mice by administration of dextran sulfate sodium (DSS). Mice were treated once daily with enoxaparin via oral or intraperitoneal administration and monitored for colitis activities. On termination (day 8), colons were collected for macroscopic evaluation and cytokine measurement, and processed for histology and immunohistochemistry. Oral but not intraperitoneal administration of enoxaparin significantly ameliorated DSS-induced colitis. Oral enoxaparin-treated mice retained their body weight and displayed less diarrhea and fecal blood loss compared to the untreated colitis group. Colon weight in enoxaparin-treated mice was significantly lower, indicating reduced inflammation and edema. Histological examination of untreated colitis mice showed a massive loss of crypt architecture and goblet cells, infiltration of immune cells and the presence of edema, while all aspects of this pathology were alleviated by oral enoxaparin. Reduced number of macrophages in the colon of oral enoxaparin-treated mice was accompanied by decreased levels of pro-inflammatory cytokines. Oral enoxaparin significantly reduces the inflammatory pathology associated with DSS-induced colitis in mice and could therefore represent a novel therapeutic option for the management of ulcerative colitis.

Rivaroxaban Induces Mucosal Healing in a Rat Model of Trinitrobenzene Sulfonic Acid-Induced Colitis

OBJECTIVE

This study was designed to identify the effect of rivaroxaban, a direct factor Xa inhibitor, on trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats.

MATERIALS AND METHODS

Twenty-four female Wistar rats were divided into 4 groups of 6 each. Group 1 received TNBS + rivaroxaban, group 2 received TNBS + methylprednisolone, group 3 received TNBS and group 4 received a saline enema. Colitis was induced in the rats by the intracolonic administration of TNBS. Rivaroxaban and methylprednisolone were given by oral gavage daily for 7 days. The rats were killed 7 days after the induction of colitis.

RESULTS

Rivaroxaban and methylprednisolone significantly reduced gross damage and histopathological scores. Rivaroxaban was more effective than methylprednisolone in terms of microscopic mucosal healing. Rivaroxaban attenuated the accumulation of malonyldialdehyde (MDA) and transforming growth-factor β1 (TGF-β1) and the activities of myeloperoxidase (MPO), matrix metalloproteinase-3 and tissue inhibitor of metalloproteinases-1. Methylprednisolone reduced only the activity of MPO and the accumulation of MDA and TGF-β1. Superoxide dismutase activity showed a restoration to normal levels after rivaroxaban and methylprednisolone administration.

CONCLUSIONS

Rivaroxaban showed a therapeutic effect in the TNBS model of experimental colitis, and it seemed to be at least as effective as methylprednisolone. This effect may be brought about by the inhibition of oxidative stress and metalloproteinase activity associated with tissue injury and remodeling.

Cerebral arterial infarction in inflammatory bowel diseases

It has been estimated that up to 10% of hypercoagulable state manifestations in patients with inflammatory bowel disease (IBD) are ischemic strokes. The literature search through MEDLINE and EMBASE highlighted 33 case reports of IBD patients complicated with cerebral arterial infarction during the course of their disease. Most of these patients presented with either left or right sided hemiparesis on admission, while the most common site of arterial infarction was either the right or the left middle cerebral artery. Thrombocytosis and anemia were the most commonly observed potential risk factors for stroke in the laboratory analysis. Other coagulation abnormalities, hereditary thrombotic mutations, hyperhomocysteinemia, hyperlipidemia, structural cardiac abnormalities, endocarditis and cerebral artery vasculitis have also been reported in some of the cases that were reviewed. Even though many of these findings are commonly observed in IBD patients, literature data is still controversial about their causal relationship to ischemic stroke. Similarly, there is also lack of steady evidence and official guidelines for stroke management in both children and adults with IBD comorbidity. Finally, an algorithm based on both the American Heart Association and European Stroke Organization guidelines for stroke management and prevention in the general population, is presented as a reference point for the treatment of IBD patients who are complicated by an ischemic cerebral event.

Ascidian (chordate-tunicate) and mammalian heparin enemas attenuate experimental diversion colitis

AIM

We sought to investigate whether mammalian or ascidian Styela plicata heparin enemas could diminish inflammation in experimental diversion colitis.

METHODS

Wistar-specific pathogen-free rats were submitted to a Hartmann's end colostomy and treated with enemas containing mammalian or Styela plicata heparin, or saline. Enemas were administered 3 times a week in the excluded colon segment from 4 to 8 weeks after operation. The effect of treatment was evaluated using video-endoscopic and histologic scores, measuring the cytokines interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and transforming growth factor-β production in organ cultures by enzyme-linked immunosorbent assay, quantifying T cells and macrophages, and investigating nuclear factor-kappa B (NF-κB) and external mitogen-activated protein kinase (pERK) activation.

RESULTS

Treatment with either mammalian or Styela plicata heparins decreased colonoscopic and histologic scores (P < .02) and restored the densities of collagen fibers and the number of goblet cells (P < .03) in the diverted colon. Both heparin treatments decreased the accumulation of T cells and macrophages (P < .03), and the activation of NF-κB and pERK (P < .04) in the diverted colon. The high levels of cytokines IL-1β, TNF-α, and IL-6 from the diversion colitis explants decreased (P < .05) to near normal values with heparin treatments.

CONCLUSION

The improvement of experimental diversion colitis with heparin treatments indicates the anti-inflammatory effect of these compounds, even after topical administration. Further studies with the nonhemorrhagic heparin obtained from the invertebrate Styela plicata will be necessary to confirm its efficacy for the treatment of human diversion colitis and possibly other forms of colitis.

Risk factors, morbidity, and treatment of thrombosis in children and young adults with active inflammatory bowel disease

OBJECTIVES

Pediatric inpatients with inflammatory bowel disease (IBD) are rarely considered for thromboprophylaxis because of concerns about safety and underappreciation of thrombotic risk. We characterized thromboembolism (TE) in children and young adults with inflammatory bowel disease (IBD) at a single tertiary care hospital.

METHODS

We performed a retrospective review of an inpatient billing database for all IBD admissions with colonic involvement and an anticoagulation database for thrombotic complications from 2006 to 2011.

RESULTS

Of 532 patients admitted with IBD with colonic involvement, 10 (1.9%) had TE (9 venous, 1 arterial), 2 of whom had recurrent thrombosis. Many of the events resulted in considerable morbidity, including 4 cerebrovascular events and 2 pulmonary emboli. Established risk factors in IBD colitis inpatients with TE included: indwelling catheter (4/10), first-degree family member with TE (2/10), hereditary thrombophilia (3/10), smoking (1/10), oral contraceptive (1/5 females), and thalidomide (1/10). Additionally, most (8/10) patients had acquired thrombophilia, mostly elevation of factor VIII and anticardiolipin antibodies. Patients with IBD and TE received therapeutic anticoagulation without significantly increased bleeding. Thrombus resolution was documented in 7 cases, persistence in 2 cases and recurrence in 2 cases.

CONCLUSIONS

Pediatric inpatients hospitalized with IBD with colonic involvement have increased risk of TE, including complications of pulmonary embolism, recurrence, persistence, and indefinite long-term anticoagulation. Therapeutic anticoagulation in patients with IBD with active colitis appears safe. We identified both inherited thrombophilias and acquired risk factors in patients with IBD and TE. We presently use risk stratification and recommend prophylactic anticoagulation in high-risk patients.

Cerebral sinus venous thrombosis in inflammatory bowel diseases

BACKGROUND

It has been estimated that 1.3-6.4% of patients with inflammatory bowel diseases (IBD) are complicated by cerebral venous thrombosis (CVT) at some point of time during the course of their disease.

METHODS

We retrospectively reviewed and subsequently analyzed data from 65 case reports of IBD patients with CVT. Our sources included MEDLINE and EMBASE, and the references of retrieved articles were also screened.

RESULTS

Patients with CVT and IBD were significantly younger than CVT patients without IBD. Female patients were complicated more frequently but at an older age when compared with males. The incidence of ulcerative colitis was almost double compared with Crohn's disease. Active disease was detected in 78.4% of the cases and the proportions of patients with active ulcerative colitis or active Crohn's disease were almost equal. The predominant neurological symptom in these patients was persistent headache (80%) and the most common site of CVT was the superior sagittal sinus (50.7%). Severe iron deficiency anemia was highlighted as a significant risk factor for thrombosis in nearly half of the patients. Transient coagulation abnormalities and hereditary thrombogenic mutations were identified in 23 and 20% of the case reports, respectively.

CONCLUSION

The overall outcome was very good, especially in those patients who were treated acutely with heparin or low molecular weight heparin, suggesting that heparin administration is related with improved neurological outcome and decreased mortality rates even in IBD patients complicated with CVT.

Prevention of venous thromboembolism in hospitalized patients with inflammatory bowel disease

Venous thromboembolism is a relatively common and potentially serious complication in inpatients with inflammatory bowel disease (IBD). There are a number of pathophysiologic mechanisms for venous thromboembolism that are specific to patients with IBD that may be active. The use of anticoagulants for prophylaxis against venous thromboembolism in hospitalized patients with IBD needs to be balanced against the potential for worsening of rectal bleeding. Evidence from randomized trials suggests that heparin and low-molecular weight heparin are generally safe to use in patients with active IBD, and a number of guidelines support their use for thromboprophylaxis in this patient population.

Heparanase enzyme in chronic inflammatory bowel disease and colon cancer

Heparanase is the sole mammalian endoglycosidase that cleaves heparan sulfate, the key polysaccharide of the extracellular matrix and basement membranes. Enzymatic cleavage of heparan sulfate profoundly affects a variety of physiological and pathological processes, including morphogenesis, neovascularization, inflammation, and tumorigenesis. Critical involvement of heparanase in colorectal tumor progression and metastatic spread is widely documented; however, until recently a role for heparanase in the initiation of colon carcinoma remained underappreciated. Interestingly, the emerging data that link heparanase to chronic inflammatory bowel conditions, also suggest contribution of the enzyme to colonic tumor initiation, at least in the setting of colitis-associated cancer. Highly coordinated interplay between intestinal heparanase and immune cells (i.e., macrophages) preserves chronic inflammatory conditions and creates a tumor-promoting microenvironment. Here we review the action of heparanase in colon tumorigenesis and discuss recent findings, pointing to a role for heparanase in sustaining immune cell-epithelial crosstalk that underlies intestinal inflammation and the associated cancer.

Unfractionated or low molecular weight heparin for induction of remission in ulcerative colitis: a Cochrane inflammatory bowel disease and functional bowel disorders systematic review of randomized trials

BACKGROUND

We aimed to systematically review the efficacy of unfractionated heparin (UFH) or low molecular weight heparins (LMWH) for remission induction in patients with ulcerative colitis (UC).

METHODS

A literature search to April 2011 was performed to identify all randomized trials studying UFH or LMWH use in patients with UC. The Cochrane Risk of Bias Tool was used to assess study quality.

RESULTS

LMWH administered subcutaneously showed no benefit over placebo for any outcome, including clinical remission, and clinical, endoscopic, or histological improvement. High-dose LMWH administered via an extended colon-release tablet demonstrated benefit over placebo for clinical remission (odds ratio [OR] 2.73; 95% confidence interval [CI] 1.32-5.67; P = 0.007), clinical improvement (OR 2.99; 95% CI 1.30-6.87; P = 0.01), and endoscopic improvement (OR 2.25; 95% CI 1.01-5.01; P = 0.05) but not endoscopic remission or histologic improvement. LMWH was not beneficial when added to standard therapy for clinical remission, clinical improvement, endoscopic remission, or endoscopic improvement. One study examining UFH versus corticosteroids for the treatment of severe UC demonstrated the inferiority of UFH for clinical improvement. More patients assigned to UFH had rectal hemorrhage as an adverse event.

CONCLUSIONS

LMWH administered by extended colon-release tablets may be effective for the treatment of active UC. This benefit needs to be confirmed by further randomized controlled studies. The same benefits were not seen when LMWH was administered subcutaneously at lower doses. There is no evidence to support the use of UFH for the treatment of active UC.

Haemostatic system in inflammatory bowel diseases: New players in gut inflammation

Inflammation and coagulation constantly influence each other and are constantly in balance. Emerging evidence supports this statement in acute inflammatory diseases, such as sepsis, but it also seems to be very important in chronic inflammatory settings, such as inflammatory bowel disease (IBD). Patients with Crohn’s disease and ulcerative colitis have an increased risk of thromboembolic events, and several abnormalities concerning coagulation components occur in the endothelial cells of intestinal vessels, where most severe inflammatory abnormalities occur. The aims of this review are to update and classify the type of coagulation system abnormalities in IBD, and analyze the strict and delicate balance between coagulation and inflammation at the mucosal level. Recent studies on possible therapeutic applications arising from investigations on coagulation abnormalities associated with IBD pathogenesis will also be briefly presented and critically reviewed.

Thrombosis and inflammatory bowel disease: a call for improved awareness and prevention

Thrombotic complications in patients with inflammatory bowel disease (IBD) are common and require improved awareness and prevention. In this review the interface between IBD and thrombosis is discussed, with emphasis on risk assessment and data to aid clinical decision making. Thromboembolic complications are 3-fold more likely in IBD patients than controls and the relative risk exceeds 15 during disease flares. Improved assessment of thrombosis risk for an individual patient includes thorough personal and family history and awareness of prothrombotic medications and lifestyle choices. Patients with the highest risk of thrombosis are those with active colonic disease, personal or strong family history of thrombosis, and those with significant acquired risk factors. Combined risk factors or hospitalization should prompt mechanical thromboprophylaxis. Indications for prophylactic anticoagulation are not defined currently by clinical studies, especially in pediatric patients, although some groups now advocate prophylactic anticoagulation for all hospitalized IBD patients and even some outpatients with disease flares. Thrombosis management requires a multidisciplinary therapeutic approach to balance anticoagulation and bleeding risk. While bleeding may occur with anticoagulation in IBD, data and experience indicate that therapeutic heparin is safe and bleeding manifestations can be managed supportively in most patients. Until prospective trials of prophylactic anticoagulation are published, management of thrombotic risk and prophylaxis in IBD will remain a clinical challenge.

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.

Unfractionated or low-molecular weight heparin for induction of remission in ulcerative colitis

BACKGROUND

There are a limited number of treatment options for patients with ulcerative colitis (UC). An increased risk of thrombosis in UC coupled with an observation that UC patients being treated with anticoagulant therapy for thrombotic events had an improvement in their bowel symptoms led to trials examining the use of unfractionated heparin (UFH) and low molecular weight heparins (LMWH) in patients with active UC.

OBJECTIVES

To review randomized trials examining the efficacy of unfractionated heparin (UFH) or low molecular weight heparins (LMWH) for remission induction in patients with ulcerative colitis.

SEARCH STRATEGY

The MEDLINE (PUBMED), and EMBASE databases, The Cochrane Central Register of Controlled Trials, the Cochrane IBD/FBD group specialized trials register, review papers on ulcerative colitis, and references from identified papers were searched up to June 2010 in an effort to identify all randomized trials studying UFH or LMWH use in patients with ulcerative colitis. Abstracts from major gastroenterological meetings were searched to identify research published in abstract form only.

SELECTION CRITERIA

Each author independently reviewed potentially relevant trials to determine their eligibility for inclusion based on the criteria identified above. The Cochrane Risk of Bias tool was used to assess study quality. Studies published in abstract form only were included if the authors could be contacted for further information.

DATA COLLECTION AND ANALYSIS

A data extraction form was developed and used to extract data from included studies. At least 2 authors independently extracted data. Any disagreements were resolved by consensus. Data were analyzed on an intention-to-treat basis. The primary outcome was induction of remission, as defined by the studies. Data were combined for analysis if they assessed the same treatments (UFH or LMWH versus placebo or other therapy).

MAIN RESULTS

LMWH administered subcutaneously showed no benefit over placebo for any outcome, including clinical remission, and clinical, endoscopic, or histological improvement. High dose LMWH administered via an extended colon-release tablet demonstrated benefit over placebo for clinical remission (OR 2.73; 95% CI 1.32 to 5.67; P = 0.007), clinical improvement (OR 2.99; 95% CI 1.30 to 6.87; P = 0.01), and endoscopic improvement (OR 2.25; 95%CI 1.01 to 5.01; P = 0.05) but not endoscopic remission or histologic improvement. LMWH was not beneficial when added to standard therapy for clinical remission, clinical improvement, endoscopic remission or endoscopic improvement. LMWH was well-tolerated but provided no significant benefit for quality of life. One study examining UFH versus corticosteroids for the treatment of severe UC demonstrated the inferiority of UFH for clinical improvement. More patients assigned to UFH had rectal hemorrhage as an adverse event.

AUTHORS' CONCLUSIONS

There is evidence to suggest that LMWH may be effective for the treatment of active UC. When administered by extended colon-release tablets, LMWH was more effective than placebo for treating outpatients with mild to moderate disease. This benefit needs to be confirmed by further randomized controlled studies. The same benefits were not seen when LMWH was administered subcutaneously at lower doses. There is no evidence to support the use of UFH for the treatment of active UC. A further trial of UFH in patients with mild disease may also be justified. Any benefit found would need to be weighed against a possible increased risk of rectal bleeding in patients with active UC.

Clinical trial: oral colon-release parnaparin sodium tablets (CB-01-05 MMX) for active left-sided ulcerative colitis

BACKGROUND

The administration of parnaparin sodium as oral colon-release tablets (CB-01-05 MMX) has been proposed as a novel approach for the treatment of ulcerative colitis (UC).

AIM

To assess the efficacy and the tolerability of 8 weeks' oral daily administration of 210 mg of parnaparin sodium compared with placebo in subjects treated with stable-doses of oral aminosalicylates.

METHODS

This multicenter, randomized, double-blind proof of concept trial compared the efficacy of CB-01-05 MMX 210 mg tablets to placebo in 141 subjects with mild to moderately active left-sided UC treated with stable-doses of aminosalicylates. The efficacy was assessed by clinical activity index (CAI), endoscopic index (EI) and histological score (HS).

RESULTS

A total of 121 subjects (61 in test group and 60 in control group) formed the per protocol (PP) population. After 8 weeks of treatment, clinical remission was achieved in 83.6% of the CB-01-05 MMX group, and in 63.3% in the comparator group (P = 0.011). This effect was also significantly evident in the test group at week 4 (P = 0.028). A significant difference was also detected in rectal bleeding, (disappeared respectively in 75.4% and 55.0%; P = 0.018), and in mucosal friability (recovered respectively in 80.3% and in 56.7%; P = 0.005).

CONCLUSIONS

CB-01-05 MMX was safe and significantly effective in treating subjects with mild-to-moderate left-sided UC treated with stable-doses of aminosalicylates.

Efficacy of intracolonic administration of low-molecular-weight heparin CB-01-05, compared to other low-molecular-weight heparins and unfractionated heparin, in experimentally induced colitis in rat

PURPOSE

Parenteral administration of low-molecular-weight heparins (LMWHs) and unfractionated heparin (UFH) resulted effective in improving the symptoms of experimental colitis in rat. Today, there is little information about their activity by intracolonic instillation. The scope of this study was to evaluate the ability of CB-01-05 (a LMWH with a mean molecular weight of about 5,700), compared to a series of other LMWHs and to UFH, directly instilled into the distal colon of the rat, to ameliorate dinitrobenzene (DNB)-induced experimental colitis.

METHOD

Adult male Wistar rats underwent colitis induction by intracolonic instillation of DNB. Starting 24 h after colitis induction, CB-01-05 (0.005-0.9 mg), other LMWHs (0.3-0.6 mg), and UFH (0.6 mg) were instilled, by rectal route, into the distal colon once a day for three consecutive days. On the day following the last administration, the animals were sacrificed and the distal colon was isolated, weighed, macroscopically examined, and processed for histology. Additional experiments in rat splenocytes, performed in order to elucidate the anti-inflammatory mechanisms of CB-01-05, were performed.

RESULTS

Among the tested items, only CB-01-05 at doses ranging from 0.2 to 0.9 mg was significantly effective in reducing colon weight increase and in improving both the mucosal damaged area and the histological score. The other LMWHs resulted far less effective, showing decreasing activity closely related with the decrease of their molecular weight, thus demonstrating their biological nonequivalence. CB-01-05 resulted also more active than UFH. CB-01-05 was shown to interfere with cytokines production by rat splenocytes, mainly inhibiting interferon (IFN)-gamma expression.

CONCLUSIONS

CB-01-05 instilled into the colon is well tolerated, has strong anti-inflammatory effect on DNB-induced colitis in rat, and is the most effective agent among other LMWHs and UFH. These results suggest that the anti-inflammatory activity of CB-01-05, together with its topical administration, could represent a new approach in the management of ulcerative colitis.

Thrombin mediates the extraintestinal thrombosis associated with experimental colitis

Recent evidence implicating tissue factor and the protein C pathway in the hypercoagulable state associated with intestinal inflammation suggests that thrombin is likely to contribute to this response. The objective of this study was to assess the role of thrombin in the extraintestinal thrombosis associated with experimental colitis. Thrombus formation was quantified in microvessels of the cremaster muscle in mice with dextran sodium sulfate (DSS)-induced colonic inflammation. The light/dye endothelial injury model was used to elicit thrombus formation in DSS colitic mice treated with either hirudin, heparin, or antithrombin III. The initiation and propagation/stabilization phases of thrombus formation were quantified using the time of onset of the thrombus and time to blood flow cessation, respectively. Thrombus formation was accelerated in arterioles of DSS colitic mice, as exhibited by significant reductions in the time of thrombus initiation and propagation/stabilization. Colitic mice treated with hirudin, heparin, or antithrombin III did not exhibit a significant change in the time of onset of the thrombus compared with untreated colitic mice. However, all three antithrombin agents largely prevented the DSS-induced reduction in the time to flow cessation following light/dye injury, with hirudin offering complete protection. These findings indicate that thrombin plays a major role in the extraintestinal thrombus formation associated with experimental colitis. Thrombin appears to contribute to the propagation/stabilization, rather than initiation, phase of the colitis-associated thrombogenesis at the distant vascular site. The results support the therapeutic use of antithrombin agents for reducing the risk of thromboembolism in patients with inflammatory bowel disease.

Oral, colonic-release low-molecular-weight heparin: an initial open study of Parnaparin-MMX for the treatment of mild-to-moderate left-sided ulcerative colitis

BACKGROUND

Efficacy of heparin and low-molecular-weight heparins (LMWHs) in inflammatory bowel disease (IBD) treatment has been suggested. The multimatrix oral formulation MMX releases active drugs in the colon, avoiding systemic absorption. Parnaparin sodium is the LMWH chosen to be carried in the MMX formulation.

AIM

To assess the safety of three different oral dosages (70, 140 and 210 mg once daily) of Parnaparin-MMX (CB-01-05) in left-sided ulcerative colitis (UC).

METHODS

Left-sided UC patients, with a mild-to-moderate relapse were enrolled. All patients received Parnaparin-MMX for 8 weeks. Clinical Activity Index (CAI), Disease Activity Index (DAI), Endoscopic Activity Index and IBD-QoL were assessed throughout the study. A strict clinical and laboratory follow-up, including assessment of anti-factor Xa activity, was performed. Clinical remission was defined as CAI <4.

RESULTS

Ten UC patients were enrolled. One patient retired for clinical deterioration. No relevant side effects, including either interference with haemostasis parameters or increased bleeding, were observed. At the end of the treatment, seven patients (70%) were in clinical remission, only one achieving endoscopic healing. Mean final CAI, DAI and IBD-QoL scores were significantly improved from baseline.

CONCLUSIONS

Parnaparin-MMX appears to be a safe treatment option in mild-to-moderate UC. Controlled studies are warranted.

Rising prevalence of venous thromboembolism and its impact on mortality among hospitalized inflammatory bowel disease patients

BACKGROUND

We sought to determine nationwide, population-based trends in rates of venous thromboembolism (VTE) among hospitalized inflammatory bowel disease (IBD) patients in the United States and to determine its mortality and economic impact.

METHODS

We analyzed discharges from the Nationwide Inpatient Sample and used ICD-9-CM codes to identify Crohn's disease (CD) and ulcerative colitis (UC) between 1998 and 2004. Rates of VTE were compared between those with and without IBD. The impact of VTE on in-hospital mortality and resource utilization was quantified using regression analysis.

RESULTS

After multivariate adjustment, both UC (OR 1.85, 95% CI 1.70-2.01) and CD discharges (OR 1.48, 95% CI 1.35-1.62) had higher rates of VTE compared to non-IBD discharges. Prevalence of VTE was greater among UC compared to CD discharges (OR 1.32, 95% CI 1.17-1.48). Among CD patients, active fistulizing disease was independently associated with greater VTE (OR 1.39, 95% CI 1.13-1.70). There was an annual 17% rise in odds of VTE among IBD admissions over 7 yr. VTE was associated with greater mortality among IBD patients (adjusted OR 2.50, 95% CI 1.83-3.43). This age- and comorbidity-adjusted excess mortality from VTE was 2.1-fold higher for IBD than for non-IBD patients (P < 0.0001). IBD patients with VTE had longer length of stay (11.7 vs 6.1 days, P < 0.0001) and incurred higher hospital charges ($47,515 vs $21,499; P < 0.0001).

CONCLUSIONS

VTE is increasingly prevalent among hospitalized IBD patients and has substantial mortality and economic impact. These findings drive the need for widespread prophylaxis against and early detection of VTE among IBD inpatients.

Unfractionated or low-molecular weight heparin for induction of remission in ulcerative colitis

BACKGROUND

There are a limited number of treatment options for patients with ulcerative colitis (UC). An increased risk of thrombosis in UC coupled with an observation that UC patients being treated with anticoagulant therapy for thrombotic events had an improvement in their bowel symptoms led to trials examining the use of unfractionated heparin (UFH) and low molecular weight heparins (LMWH) in patients with active UC.

OBJECTIVES

To review randomized trials examining the efficacy of unfractionated heparin (UFH) or low molecular weight heparins (LMWH) for remission induction in patients with ulcerative colitis.

SEARCH STRATEGY

The MEDLINE (PUBMED), and EMBASE databases, The Cochrane Central Register of Controlled Trials, the Cochrane IBD/FBD group specialized trials register, review papers on ulcerative colitis, and references from identified papers were searched in an effort to identify all randomized trials studying UFH or LMWH use in patients with ulcerative colitis. Abstracts from major gastroenterological meetings were searched to identify research published in abstract form only.

SELECTION CRITERIA

Each author independently reviewed potentially relevant trials to determine their eligibility for inclusion based on the criteria identified above. The Jadad scale was used to assess study quality. Studies published in abstract form only were included if the authors could be contacted for further information.

DATA COLLECTION AND ANALYSIS

A data extraction form was developed and used to extract data from included studies. At least 2 authors independently extracted data. Any disagreements were resolved by consensus. Data were analyzed using Review Manager (RevMan 4.2.9). Data were analyzed on an intention-to-treat basis, and treated dichotomously. In cross-over studies, only data from the first arm were included. The primary endpoint was induction of remission, as defined by the studies. Data were combined for analysis if they assessed the same treatments (UFH or LMWH versus placebo or other therapy). If a comparison was only assessed in a single trial, P-values were derived using the chi-square test. If the comparison was assessed in more than one trial, summary test statistics were derived using the Peto odds ratio and 95% confidence intervals (95% CI). The presence of heterogeneity among studies was assessed using the chi-square test (a P value of 0.10 was regarded as statistically significant). If statistically significant heterogeneity was identified the odds ratio and 95% CI were calculated using a random effects model.

MAIN RESULTS

There were 2 randomized, double-blind studies assessing LMWH versus placebo for the treatment of mild-moderate active UC. Various outcomes were assessed in the 2 studies. LMWH showed no benefit over placebo in any outcome, including clinical remission (OR 1.09; 95% CI 0.26 to 4.63; P = 0.91), clinical improvement (OR 0.73; 95% CI 0.32 to 1.66; P = 0.45 and OR 1.09; 95% CI 0.18 to 6.58; P = 0.92 in the two studies, respectively), endoscopic improvement (OR 1.35; 95% CI 0.29 to 6.18; P = 0.70), or histological improvement (OR 2.00; 95% CI 0.45 to 8.96; P = 0.37). LMWH was also not beneficial when added to standard therapy in a randomized open-label trial in which the outcome measures included clinical remission (OR 0.71; 95% CI 0.17 to 2.95; P = 0.64), clinical improvement (OR 2.00; 95% CI 0.31 to 12.75; P = 0.46), endoscopic remission (OR 0.71; 95% CI 0.17 to 2.95; P = 0.64), or endoscopic improvement (OR 1.40; 95% CI 0.34 to 5.79; P = 0.64). LMWH was well-tolerated and provided no significant benefit for quality of life. One study examining UFH versus corticosteroids in the treatment of severe UC demonstrated inferiority of UFH in clinical improvement as an outcome measure (OR 0.02; 95% CI 0 to 0.40; P = 0.01). Patients assigned to UFH did not improve clinically. More patients assigned to UFH had rectal hemorrhage as an adverse event.

AUTHORS' CONCLUSIONS

There is no evidence to support the use of UFH or LMWH for the treatment of active UC. No further trials examining these drugs for patients with UC are warranted, except perhaps a trial of UFH in patients with mild disease. Any benefit found would need to be weighed against a possible increased risk of rectal bleeding in patients with active UC.

Meta-analysis: The utility and safety of heparin in the treatment of active ulcerative colitis

BACKGROUND

The use of heparin for the treatment of ulcerative colitis has been evaluated in several open and controlled trials, with varying outcomes.

AIM

To evaluate the efficacy and safety of heparin as supplemental therapy compared with conventional therapy in patients with ulcerative colitis.

METHODS

All randomized trials comparing heparin supplementation to conventional therapy were included from electronic databases. Statistical analysis was performed with review manager 4.2.8 (The Cochrane Collaboration, Oxford, UK). Sub-analysis and sensitivity analysis were also performed.

RESULTS

Eight randomized-controlled trials, investigating a total of 454 participants, met the inclusion criteria. The odds ratio (OR) for the efficacy of heparin supplementation vs. conventional therapy was 0.78 (95% CI = 0.50-1.21). Few serious adverse events were observed. The OR for the efficacy of unfractionated heparin and low-molecular-weight heparin vs. conventional therapy was 0.26 (95% CI = 0.07-0.93) and 0.92 (95% CI = 0.57-1.47), respectively. The OR for the efficacy of heparin vs. conventional therapy with placebo was 0.87 (95% CI = 0.53-1.44).

CONCLUSIONS

Our meta-analysis suggests that administration of heparin in patients with ulcerative colitis is safe, but no additive benefit over conventional therapy is indicated.