Elevated circulating platelet-derived microparticles in patients with active inflammatory bowel disease

Assessment of Extracellular Particles Directly in Diluted Plasma and Blood by Interferometric Light Microscopy. A Study of 613 Human and 163 Canine Samples

Extracellular nanoparticles (EPs) are a subject of increasing interest for their biological role as mediators in cell-cell communication; however, their harvesting and assessment from bodily fluids are challenging, as processing can significantly affect samples. With the aim of minimizing processing artifacts, we assessed the number density (n) and hydrodynamic diameter (Dh) of EPs directly in diluted plasma and blood using the following recently developed technique: interferometric light microscopy (ILM). We analyzed 613 blood and plasma samples from human patients with inflammatory bowel disease (IBD), collected in trisodium citrate and ethylenediaminetetraacetic acid (EDTA) anticoagulants, and 163 blood and plasma samples from canine patients with brachycephalic obstructive airway syndrome (BOAS). We found a highly statistically significant correlation between n in the plasma and n in the blood only in the human (i.e., but not canine) blood samples, between the samples with trisodium citrate and EDTA, and between the respective Dh for both species (all p < 10-3). In the human plasma, the average was 139 ± 31 nm; in the human blood, was 158 ± 11 nm; in the canine plasma, was 155 ± 32 nm; and in the canine blood, was 171 ± 33 nm. The differences within species were statistically significant (p < 10-2), with sufficient statistical power (P > 0.8). For , we found no statistically significant differences between the human plasma and blood samples or between the samples with trisodium citrate and EDTA. Our results prove that measuring n and Dh of EPs in minimally processed fresh blood and in diluted fresh plasma by means of ILM is feasible for large populations of samples.

The Role of Platelet-Derived Extracellular Vesicles in Immune-Mediated Thrombosis

Platelet-derived extracellular vesicles (PEVs) play important roles in hemostasis and thrombosis. There are three major types of PEVs described based on their size and characteristics, but newer types may continue to emerge owing to the ongoing improvement in the methodologies and terms used to define various types of EVs. As the literature on EVs is growing, there are continuing attempts to standardize protocols for EV isolation and reach consensus in the field. This review provides information on mechanisms of PEV production, characteristics, cellular interaction, and their pathological role, especially in autoimmune and infectious diseases. We also highlight the mechanisms through which PEVs can activate parent cells in a feedback loop.

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.

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.

Alteration of Gut Microbiota in Carbapenem-Resistant Enterobacteriaceae Carriers during Fecal Microbiota Transplantation According to Decolonization Periods

Fecal microbiota transplantation (FMT) has been suggested as an alternative therapeutic option to decolonize carbapenem-resistant Enterobacteriaceae (CRE). However, the analysis of gut microbiota alteration in CRE carriers during FMT is still limited. Here, gut microbiota changes in CRE carriers were evaluated during FMT according to decolonization periods. The decolonization of 10 CRE carriers was evaluated after FMT, using serial consecutive rectal swab cultures. Alterations of gut microbiota before and after FMT (56 serial samples) were analyzed using high-throughput sequencing. The decolonization rates of CRE carriers were 40%, 50%, and 90% within 1, 3 and 5 months after initial FMT, respectively. Gut microbiota significantly changed after FMT (p = 0.003). Microbiota alteration was different between the early decolonization carriers (EDC) and late decolonization carriers (LDC). Microbiota convergence in carriers to donors was detected in EDC within 4 weeks, and keystone genera within the Bacteroidetes were found in the gut microbiota of EDC before FMT. The relative abundance of Klebsiella was lower in EDC than in LDC, before and after FMT. Our results indicate that FMT is a potential option for CRE decolonization. The gut microbiota of CRE carriers could be used to predict decolonization timing after FMT, and determine repeated FMT necessity.

Bacteriophage-mediated manipulation of the gut microbiome – promises and presents limitations

Gut microbiome (GM) composition and function are linked to human health and disease, and routes for manipulating the GM have become an area of intense research. Due to its high treatment efficacy, the use of fecal microbiota transplantation (FMT) is generally accepted as a promising experimental treatment for patients suffering from GM imbalances (dysbiosis), e.g. caused by recurrent Clostridioides difficile infections (rCDI). Mounting evidence suggests that bacteriophages (phages) play a key role in successful FMT treatment by restoring the dysbiotic bacterial GM. As a refinement to FMT, removing the bacterial component of donor feces by sterile filtration, also referred to as fecal virome transplantation (FVT), decreases the risk of invasive infections caused by bacteria. However, eukaryotic viruses and prophage-encoded virulence factors remain a safety issue. Recent in vivo studies show how cascading effects are initiated when phage communities are transferred to the gut by e.g. FVT, which leads to changes in the GM composition, host metabolome, and improve host health such as alleviating symptoms of obesity and type-2-diabetes (T2D). In this review, we discuss the promises and limitations of FVT along with the perspectives of using FVT to treat various diseases associated with GM dysbiosis.

Platelets release proinflammatory microparticles in anti-neutrophil cytoplasmic antibody-associated vasculitis

OBJECTIVES

The biological functions of the platelets contributing to ANCA-associated vasculitis (AAV) are largely unclear. The current study aimed to investigate the potential role of platelet-derived microparticles (PMPs) in AAV.

METHODS

In the current study, microparticles in AAV patients were analysed by flow cytometry, and PMPs were probed for relative levels of 640 bioactive proteins secreted from patients' platelets using antibody microarrays. These data were then correlated with clinical and pathological parameters.

RESULTS

PMPs were significantly increased in 69 AAV patients, predominantly MPO-ANCA positive patients in active stage compared with in remission [4406.8/μl (2135.4, 5485.0) vs 549.7/μl (350, 708.5), P < 0.0001], and 43% of microparticles in active AAV were PMPs. Compared with 15 patients in remission, highly expressed proinflammatory molecules in the microparticles from platelets in 15 AAV patients in active stage revealed that potential functions of PMPs were promotion of the effect of chemotaxis, adhesion, growth and apoptosis (all the patients for array analysis were MPO-ANCA positive). The level of PMPs had a significant association with disease activity, inflammation, and renal damage.

CONCLUSION

PMPs may serve as inflammatory propagators through their wide production of proinflammatory cytokines in AAV, potentially providing a novel therapeutic target.

Atypical Clinical Presentation of Crohn's Disease with Superior Mesenteric Vein Obstruction and Protein-losing Enteropathy

We herein report a 44-year-old man suffering from systemic edema due to protein-losing enteropathy (PLE) with superior mesenteric vein (SMV) obstruction and development of collateral veins, which subsequently proved to be a chronic result of thrombosis and a complication of Crohn's disease (CD). PLE was supposedly induced by both intestinal erosion and thrombosis-related lymphangiectasia, which was histologically proven in his surgically-resected ileal stenosis. Elemental diet and anti-TNFα agent improved his hypoalbuminemia after surgery. The rarity of the simultaneous coexistence of SMV obstruction and PLE and the precedence of these complications over typical abdominal symptoms of CD made the clinical course complex.

Microparticles Produced by Activated Platelets Carry a Potent and Functionally Active Angiogenic Signal in Subjects with Crohn's Disease

Microparticles (MPs) are submicron vesicles shed from various cell types upon activation, stimulation, and death. Activated platelets are an important source of circulating MPs in subjects with inflammatory diseases, including Crohn’s disease (CD). Angiogenesis is a hallmark of inflammation in CD and plays an active role in sustaining disease progression, while targeting angiogenesis may be an effective approach to block colitis. In this study, we analyzed the angiogenic content of the MPs produced by activated platelets in subjects with CD. We also evaluated whether the angiogenic signal carried by these MPs was functionally active, or able to induce angiogenesis. We found that, in subjects with CD, MPs produced by activated platelets contain significantly higher levels of angiogenic mRNAs, such as epidermal growth factor (EGF), platelet-derived growth factor-α (PDGFα), fibroblast growth factor (FGF-2), and angiopoietin-1 (ANGPT1), compared to MPs isolated from control subjects. They also contain significantly higher levels of prototypical angiogenic proteins, including vascular endothelial growth factor (VEGF), angiopoietin-1, endoglin, endothelin-1, pentraxin 3, platelet factor-4, plasminogen activator inhibitor-1 (PAI-1), tissue inhibitor of metalloproteinases-1 (TIMP-1), and thrombospondin 1. The protein content of these MPs is functionally active, since it has the ability to induce a robust angiogenic process in an endothelial cell/interstitial cell co-culture in vitro assay. Our results reveal a potential novel mechanism through which the angiogenic signal is delivered in subjects with CD, with potentially important clinical and therapeutic implications.

Diagnostic Markers for Nonspecific Inflammatory Bowel Diseases

The nonspecific inflammatory bowel diseases (IBD) represent a heterogeneous group of chronic inflammatory disorders of the gastrointestinal tract, and Leśniowski-Crohn's disease (CD) and ulcerative colitis (UC) are among the two major clinical forms. Despite the great progress in understanding the pathogenesis of these diseases, their etiology remains unclear. Genetic, immune, and environmental factors are thought to play a key role. The correct diagnosis of nonspecific inflammatory bowel diseases as well as the determination of disease activity, risk stratification, and prediction of response to therapy still relies on a multidisciplinary approach based on clinical, laboratory, endoscopic, and histologic examination. However, considerable effort has been devoted to the development of an accurate panel of noninvasive biomarkers that have increased diagnostic sensitivity and specificity. Laboratory biomarkers useful in differentiating IBD with functional disorders and in evaluating disease activity, prognosis, and treatment selection for IBD are presented in this study.

Increased levels of circulating platelet derived microparticles in Crohn's disease patients

OBJECTIVE

Platelet activation is a consistent feature in inflammatory bowel disease. However, the role of circulating platelet derived microparticles (PDMPs) and the effects of disease activity and treatment on their levels has not been clarified yet in this disorder.

MATERIAL AND METHODS

Using flow cytometry, we measured platelet derived microparticles and platelet derived microparticles expressing Annexin V in platelet rich plasma from 47 Crohn's disease and 43 ulcerative colitis patients and 24 healthy controls.

RESULTS

Crohn's disease patients have greater PDMPs (0.31% ± 0.07% versus 0.14% ± 0.04%, p = 0.02) and PDMPs expressing Annexin V (27% ± 2.6% versus 14.6% ± 2.7%, p = 0.002) levels in comparison with healthy controls; however, both microparticles levels are not related with disease activity. Crohn's disease patients on 5-ASA therapy show lower levels of PDMPs in comparison with those on no 5-ASA (0.30% ± 0.07% versus 0.32% ± 0.09%, p = 0.048). Ulcerative colitis patients have similar PDMPs and PDMPs expressing Annexin V levels, compared to healthy controls (p = 0.06 and p = 0.2, respectively) and there is no correlation of both microparticles expression with disease activity. 5-ASA has no effect on both microparticles levels in ulcerative colitis patients. Anti-TNF-α treatment has no effect on study's microparticles expression in Crohn's and ulcerative colitis patients.

CONCLUSIONS

Circulating levels of platelet derived microparticles are increased only in Crohn's patients, but they do not correlate with disease activity. 5-ASA treatment is associated with lower levels of PDMPs only in Crohn's, while anti-TNF-α treatment does not influence expression of microparticles in inflammatory bowel disease patients.

Distinct features of circulating microparticles and their relationship with disease activity in inflammatory bowel disease

Background

There is evidence that circulating microparticles (MPs) and annexin (+) platelet-derived MPs (PDMPs) are increased in inflammatory bowel disease (IBD). The aim of our study was to characterize the abundance, origin, and annexin V binding of MPs in patients with IBD and correlate them with the disease characteristics.

Methods

Case-control study of 46 IBD patients (23 Crohn’s disease, 23 ulcerative colitis) and 40 matched healthy controls (HC). MPs were divided according to annexin V binding, their origin was estimated based on specific cell membrane markers in plasma samples and their number was calculated via flow cytometry. Clinical and laboratory activity indices were also analyzed.

Results

Annexin (-) PDMPs (P=0.0004), total (P=0.04) and annexin (+) monocyte-derived MPs (P=0.02) were increased and annexin (-) total MPs (P=0.0007) were decreased in IBD patients compared to HC. The annexin (+)/(-) ratio of all MP types were significantly elevated in IBD patients compared to HC (P<0.003). IBD patients with active disease displayed elevated total and annexin (+) total MPs, total, annexin (+) and (-) PDMPs compared with those in remission (P<0.05). Annexin (-) PDMPs were considerably increased in IBD patients with active compared to those with inactive disease (P=0.0013). Total and annexin (-) PDMPs were significantly correlated with most of the disease activity indices (P<0.05).

Conclusion

The majority of circulating MPs, their counterparts and particularly annexin (-) PDMPs are increased in active IBD patients. Annexin (+)/(-) ratio proved to be the most reliable distinctive MP index between HC and IBD patients.

Association of the Plasma Platelet-Derived Microparticles to Platelet Count Ratio with Hospital Mortality and Disseminated Intravascular Coagulopathy in Critically Ill Patients

AIM

The role of platelet-derived microparticles (PDMPs) in the crosstalk between coagulopathy and inflammation in critically ill patients remains unclear. The aim of this cohort observational study was to investigate the associations between the PDMP levels and hospital mortality or disseminated intravascular coagulopathy (DIC).

METHODS

This study included 119 patients who were admitted to the ICU. The PDMP levels were measured using an enzyme-linked immunosorbent assay three times a week, for a total of 372 samples. We calculated the maximum (max) PDMP value, max PDMP/platelet (PDMP/Plts) ratio (converted to the PDMP levels per 10(4) platelets) and nadir platelet count during the ICU stay. Baseline patient data and scores, including the Japanese Association for Acute Medicine (JAAM) DIC score, were collected, and potential predictors were analyzed for possible associations with hospital mortality.

RESULTS

The max PDMP/Plts ratio was significantly different comparing the survivors (n=98: median, 2.54) and non-survivors (n=21: median 17.59; p＜0.001). There was a weak but statistically significant negative correlation between the max PDMP level and nadir platelet count (r=-0.332, p＜0.001). The max PDMP level and max PDMP/Plts ratio were higher in the DIC group (81.48 and 9.27, respectively) than in the non-DIC group (34.88 and 2.35, p=0.001 and p＜0.001, respectively). The max PDMP/Plts ratio was the only variable found to be independently associated with hospital mortality according to a multivariate logistic regression analysis.

CONCLUSIONS

PDMPs are involved in the development of DIC but are not related to hospital mortality. There is a good association between the PDMP/Plts ratio and hospital mortality and/or DIC in critically ill patients.

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.

Microparticle analysis in disorders of hemostasis and thrombosis

Microparticles (MPs) are submicron vesicles released from the plasma membrane of eukaryotic cells in response to activation or apoptosis. MPs are known to be involved in numerous biologic processes, including inflammation, the immune response, cancer metastasis, and angiogenesis. Their earliest recognized and most widely accepted role, however, is the ability to promote and support the process of blood coagulation. Consequently, there is ongoing interest in studying MPs in disorders of hemostasis and thrombosis. Both phosphatidylserine (PS) exposure and the presence of tissue factor (TF) in the MP membrane may account for their procoagulant properties, and elevated numbers of MPs in plasma have been reported in numerous prothrombotic conditions. To date, however, there are few data on true causality linking MPs to the genesis of thrombosis. A variety of methodologies have been employed to characterize and quantify MPs, although detection is challenging due to their submicron size. Flow cytometry (FCM) remains the most frequently utilized strategy for MP detection; however, it is associated with significant technological limitations. Additionally, preanalytical and analytical variables can influence the detection of MPs by FCM, rendering data interpretation difficult. Lack of methodologic standardization in MP analysis by FCM confounds the issue further, although efforts are currently underway to address this limitation. Moving forward, it will be important to address these technical challenges as a scientific community if we are to better understand the role that MPs play in disorders of hemostasis and thrombosis.

The role of glycosylation in IBD

A number of genetic and immunological studies give impetus for investigating the role of glycosylation in IBD. Experimental mouse models have helped to delineate the role of glycosylation in intestinal mucins and to explore the putative pathogenic role of glycosylation in colitis. These experiments have been extended to human studies investigating the glycosylation patterns of intestinal mucins as well as levels of glycans of serum glycoproteins and expression of glycan receptors. These early human studies have generated interesting hypotheses regarding the pathogenic role of glycans in IBD, but have generally been restricted to fairly small underpowered studies. Decreased glycosylation has been observed in the intestinal mucus of patients with IBD, suggesting that a defective inner mucus layer might lead to increased bacterial contact with the epithelium, potentially triggering inflammation. In sera, decreased galactosylation of IgG has been suggested as a diagnostic marker for IBD. Advances in glycoprofiling technology make it technically feasible and affordable to perform high-throughput glycan pattern analyses and to build on previous work investigating a much wider range of glycan parameters in large numbers of patients.

Neutrophil Phagocytosis of Platelets in the Early Phase of 2,4,6-trinitro-1-chlorobenzene (TNCB)-induced Dermatitis in Mice

Activated platelets form platelet–leukocyte aggregates in the circulation in inflammatory diseases. We investigated whether activated platelets in inflamed skin tissues are phagocytized and removed by neutrophils. To investigate the kinetics of platelets and neutrophils, we immunohistochemically examined the spatiotemporal distribution of them in a murine model of 2,4,6-trinitro-1-chlorobenzene (TNCB)-induced dermatitis by using confocal and structured illumination microscopy. Four hours after elicitation, aggregates of CD41-positive platelets were adhered to CD31-positive endothelial cells within the vessels, and CD62P and PF4, markers of activated platelets, were expressed on platelet aggregates. At 8 hour post-elicitation, fragmented CD41-positive platelets were located both inside and outside vessels. Twenty-four hours after elicitation, the number of Ly-6G-positive neutrophils ingesting fragmented CD41-positive platelets outside vessels was increased, and CD62P and PF4 expression on the phagocytosed platelets was no longer observed. Disc-shaped CD41-positive platelets were not found outside vessels at any time during the experiment. Our data revealed that aggregates of activated platelets inside vessels were ingested and removed by neutrophils in the early stage of TNCB-induced dermatitis, suggesting that the process of removal of activated platelets by neutrophils may play an important role not only in the early phase of skin inflammation but also in other types of acute inflammation.

Multipotent role of platelets in inflammatory bowel diseases: A clinical approach

There is evidence that inflammatory bowel diseases (IBD) combine both inflammation and coagulation in their pathogenesis and clinical manifestations. Although platelets (PLT) are well known for their role in hemostasis, there are a rising number of studies supporting their considerable role as inflammatory amplifiers in chronic inflammatory conditions. IBD are associated with several alterations of PLT, including number, shape, and function, and these abnormalities are mainly attributed to the highly activated state of circulating PLT in IBD patients. When PLT activate, they increase in size, release a great variety of bio-active inflammatory and procoagulant molecules/particles, and express a variety of inflammatory receptors. These inflammatory products may represent a part of the missing link between coagulation and inflammation, and can be considered as possible IBD pathogenesis instigators. In clinical practice, thrombocytosis is associated both with disease activity and iron deficiency anemia. Controlling inflammation and iron replacement in anemic patients usually leads to a normalization of PLT count. The aim of this review is to update the role of PLT in IBD and present recent data revealing the possible therapeutic implications of anti-PLT agents in future IBD remedies.

Thrombosis in inflammatory bowel disease: are we tailoring prophylaxis to those most at risk?

Inflammatory bowel disease (IBD) is a disease-specific risk factor for incident and recurrent venous thromboembolism (VTE). The reasons are acquired, multifactorial, and related to prothrombotic aberrations during active disease, although the mechanisms remain incompletely elucidated. VTE represents a potentially life-threatening extraintestinal manifestation of IBD, but the associated morbidity and mortality can be reduced by appropriate use of thromboprophylaxis. Nevertheless, despite international guidelines advocating thromboprophylaxis in hospitalised patients with IBD, practice is highly variable, since 65% of gastroenterologists may not use pharmacological VTE prophylaxis in hospitalised patients with acute severe colitis. Furthermore, there is no guidance on appropriate prophylaxis for ambulatory outpatients with active disease who are at an appreciable risk of VTE. Thus the question: are we tailoring thromboprophylaxis to those patients with IBD who are most at risk?

Elevated platelet expression of CD36 may contribute to increased risk of thrombo-embolism in active inflammatory bowel disease

CONTEXT

Inflammatory bowel disease (IBD) induces increased risk of thrombo-embolism. CD36 is involved in platelet activation, glucose metabolism and inflammation.

OBJECTIVE

The relationship between CD36 expression on platelets and monocytes, plasma sCD36, and CD36-positive platelet-derived microparticles (PDMPs) and inflammation in both active IBD and after one week of anti-tumour necrosis alpha antibody (anti-TNF) treatment was investigated.

MATERIAL AND METHODS

Patients with exacerbation of Crohn's disease (n = 8) or ulcerative colitis (n = 5) and 13 healthy controls were enrolled. Seven patients underwent anti-TNF treatment for one week. Platelet, monocyte, and PDMP-CD36 were measured by flow-cytometry.

RESULTS

Platelet CD36 expression was 34% higher in patients, and correlated with insulin resistance and fasting glucose. sCD36 was 37% lower and restored after anti-TNF treatment.

CONCLUSION

Elevated platelet CD36 expression may contribute to increased risk of thrombo-embolism in active IBD. This may not entirely be attributed to inflammation and secondary insulin resistance may play a role.

Circulating microparticles from Crohn's disease patients cause endothelial and vascular dysfunctions

Background

Microparticles (MPs) are small vesicles released during cell activation or apoptosis. They are involved in coagulation, inflammation and vascular dysfunction in several diseases. We characterized circulating MPs from Crohn’s Disease (CD) patients and evaluated their effects on endothelial function and vascular reactivity after in vivo injection into mice.

Methods

Circulating MPs and their cellular origins were examined by flow cytometry from blood samples from healthy subjects (HS) and inactive or active CD patients. MPs were intravenously injected into mice. After 24 hours, endothelial function and vascular reactivity were assessed.

Results

Circulating MP levels did not differ between HS and inactive CD patients except for an increase in leukocyte-derived MPs in CD. Active CD patients compared to HS displayed increased total circulating MPs, pro-coagulant MPs and those from platelets, endothelium, erythrocytes, leukocytes, activated leukocytes and activated platelets. A significant correlation was found between total levels of MPs, those from platelets and endothelial cells, and the Harvey-Bradshaw clinical activity index. MPs from CD, but not from HS, impaired endothelium-dependent relaxation in mice aorta and flow-induced dilation in mice small mesenteric arteries, MPs from inactive CD patients being more effective than those from active patients. CDMPs induced vascular hypo-reactivity in aorta that was prevented by a nitric oxide (NO)-synthase inhibitor, and was associated with a subtle alteration of the balance between NO, reactive oxygen species and the release of COX metabolites.

Conclusions

We provide evidence that MPs from CD patients significantly alter endothelial and vascular function and therefore, may play a role in CD pathophysiology, at least by contributing to uncontrolled vascular-dependent intestinal damage.

Increased procoagulant function of microparticles in pediatric inflammatory bowel disease: role in increased thrombin generation

OBJECTIVES

Patients with inflammatory bowel disease (IBD) have a higher risk for venous thromboembolism compared with non-IBD subjects. The pathogenic mechanisms of the thrombotic events are not fully understood. We investigated levels of circulating microparticles and their influence on thrombin generation in pediatric patients with IBD during active and quiescent disease compared with healthy controls.

METHODS

Plasma samples were collected from 33 pediatric patients with Crohn disease (CD), 20 pediatric patients with ulcerative colitis (UC), and 60 healthy controls. Microparticles' procoagulant activity was measured by enzyme-linked immunosorbent assay, and the dependency of thrombin generation on microparticles-derived tissue factor was determined by means of calibrated automated thrombography.

RESULTS

The procoagulant function of microparticles was significantly increased in patients with active and inactive CD, and active UC compared with controls. Endogenous thrombin potential was significantly higher in patients with CD and UC compared with controls. A minor influence of microparticles on thrombin generation was only observed for patients with active UC.

CONCLUSIONS

Our study shows increased procoagulant function of microparticles in pediatric patients with active and quiescent CD and active UC compared with controls, but demonstrates that they are not a major cause for the higher thrombin generation in pediatric patients with IBD.

Tissue factor exposing microparticles in inflammatory bowel disease

BACKGROUND

Circulating procoagulant microparticles (MPs) are thought to be involved in the pathogenesis of venous thromboembolism in patients with inflammatory bowel disease (IBD). However, the exposure of tissue factor, the primary initiator of coagulation activation, on microparticles (TF(+)MPs) and its association with hemostasis activation has not yet been studied in IBD patients.

METHODS

In this case-control study 49 IBD patients (28 Crohn's disease, 21 ulcerative colitis) and 49 sex- and age-matched, healthy controls were included. Clinical disease activity (Crohn's Disease Activity Index and Clinical Activity Index, respectively) was assessed and IBD-related data were determined by chart review. Numbers, cellular origin and procoagulant activity of TF(+)MPs in plasma were determined using flow cytometry and a chromogenic activity assay. D-dimer and high-sensitive C-reactive protein (CRP) served as markers for coagulation activation and inflammation, respectively. The primary endpoint was the number of TF(+)MPs in IBD patients compared to controls.

RESULTS

Median number (interquartile range) of TF(+)MPs was higher in IBD patients than in controls (14.0 (11.9-22.8)×10(3)/mL vs. 11.9 (11.9-19.1)×10(3)/mL plasma, P=0.029). This finding was due to generally higher plasma levels of MPs from platelets and leukocytes in IBD patients. However, the number of TF(+)MPs was neither correlated with their procoagulant activity and D-dimer nor with disease activity and CRP.

CONCLUSIONS

Increased numbers of circulating TF(+)MPs represent a new facet of hemostatic abnormalities in IBD. However, the lack of association with activation of the coagulation system and disease activity questions their pathogenetic role for venous thromboembolism in this patient group.

Microparticles: biomarkers and beyond

Membrane microparticles are submicron fragments of membrane shed into extracellular space from cells under conditions of stress/injury. They may be distinguished from other classes of extracellular vesicles (i.e. exosomes) on the basis of size, content and mechanism of formation. Microparticles are found in plasma and other biological fluids from healthy individuals and their levels are altered in various diseases, including diabetes, chronic kidney disease, pre-eclampsia and hypertension among others. Accordingly, they have been considered biomarkers of vascular injury and pro-thrombotic or pro-inflammatory conditions. In addition to this, emerging evidence suggests that microparticles are not simply a consequence of disease, but that they themselves may contribute to pathological processes. Thus microparticles appear to serve as both markers and mediators of pathology. The present review examines the evidence for microparticles as both biomarkers of, and contributors to, the progression of disease. Approaches for the detection of microparticles are summarized and novel concepts relating to the formation of microparticles and their biological effects are examined.

Factor v leiden and inflammation

Factor V Leiden, is a variant of human factor V (FV), also known as proaccelerin, which leads to a hypercoagulable state. Along these years, factor V Leiden (FVL) has been studied from the pathophysiologic point of view, and research has been focused on finding clinical approaches for the management of the FVL associated to a trombophilic state. Less attention has been paid about the possible role of FVL in inflammatory conditions known to be present in different disorders such as uremia, cirrhosis, liver transplantation, depression as well as sepsis, infection or, inflammatory bowel disease (IBD). Whether platelet FVL will increase the activation of coagulation and/or in which proportion is able to determine the final outcome in the previously mentioned inflammatory conditions is a subject that remains uncertain. This paper will review the association of FVL with inflammation. Specifically, it will analyze the important role of the endothelium and the contribution of other inflammatory components involved at both the immune and vascular levels. This paper will also try to emphasize the importance of being a FVL carrier in associations to diseases where a chronic inflammation occurs, and how this condition may be determinant in the progression and outcome of a specific clinic situation.

Microparticles: targets and tools in cardiovascular disease

Cells communicate with other cells not only via direct cell-cell contact and the production of signaling molecules but also through release of microparticles (MPs). MPs are small vesicles released from stimulated and/or apoptotic cells. They harbor membrane proteins that are characteristic of the original parent cell and intracellular components involved in cell signaling. MPs are considered to be both biomarkers and effectors of cell signaling that maintain and/or initiate cell dysfunction. Thus, MPs can evoke endothelial dysfunction by decreasing nitric oxide (NO) production and promoting vascular inflammation which favor the prothrombotic state in atherosclerosis. Novel pharmacological approaches targeting MP production or properties could be used to treat cardiovascular pathologies. Paradoxically, another useful approach might be to employ engineered MPs with modified compositions as therapeutic agents to correct cardiovascular pathologies. This review is focused on the mechanisms of MP formation and their effects on target cells under physiological or pathophysiological conditions.

Leukocytapheresis in pediatric patients with ulcerative colitis

OBJECTIVE

Leukocytapheresis (LCAP) is a nonpharmacologic therapy that has recently been used to treat ulcerative colitis (UC). This multicenter open-label study prospectively assessed the efficacy and safety of LCAP in pediatric patients with UC.

PATIENTS AND METHODS

Twenty-three patients ages 8 to 16 years with moderate (n = 19) to severe (n = 4) steroid-resistant UC were enrolled. One of 2 LCAP columns with different volumes (model EX and the half-volume model EI) was selected, according to body weight. LCAP was performed once per week for 5 consecutive weeks. Clinical and laboratory data were collected at predetermined time points. The primary endpoint was decreased stool frequency/hematochezia score, and secondary endpoints were clinical, laboratory, and endoscopic improvements.

RESULTS

The stool frequency/hematochezia score decreased significantly from 4.5 ± 1.2 before treatment to 1.6 ± 1.9 after the fifth treatment. Clinical parameters, including stool frequency, presence of visible blood, abdominal pain, and body temperature, were significantly improved. Fecal calprotectin decreased significantly. Endoscopic findings evaluated using Matts score also improved (P < 0.01). The steroid dose decreased from 1.1 ± 0.4 mg/kg before treatment to 0.8 ± 0.5 mg/kg after treatment. There were no significant differences in changes between the EX and EI columns. The incidence of adverse effects was 61%, although none was serious. The most common adverse effects were decreased hematocrit and hemoglobin concentration.

CONCLUSIONS

The present study showed that LCAP was well tolerated in children with UC, mostly moderate, and was as effective as in adults. The types of pediatric patients best suited to LCAP remain to be determined.

New proteomic approaches for biomarker discovery in inflammatory bowel disease

There is an increasing interest in the discovery of new inflammatory bowel disease (IBD) biomarkers able to predict the future patterns of disease and to help in diagnosis, treatment, and prognosis. A biomarker is a substance that can be measured biologically and is associated with an increased risk of the disease. Biomarkers can be a genetic testing factor or proteins in biological samples such as serum, plasma, and cellular subpopulations. All of them should be studied to find out their utility in the management of IBD. Ulcerative colitis and Crohn's disease are relapsing and remitting chronic IBDs characterized by a global immune defect. The gold standard of their diagnosis is histological evaluation performed during endoscopic procedures. Several studies have focused on the identification and combination of less invasive diagnostic serum biomarkers. Nowadays, diagnostic serum tests are not able either to determine whether and when the relapse will occur once the disease is in remission state or to select a patient phenotype more responsive to a specific therapy and more susceptible to different types of complication. In this review we analyze and report the current understanding in IBD biomarkers and discuss potential future biomarkers and new developments of proteomics, such as subproteomics, as an innovative approach for the classification of patients according to their pattern of protein expression.

Platelet activation in patients with psoriasis: increased plasma levels of platelet-derived microparticles and soluble P-selectin

BACKGROUND

It has recently been established that platelets have an important role in increasing inflammation, in addition to their main role in hemostasis and thrombosis. An increased incidence of occlusive vascular disease has been reported in patients with psoriasis and the pathomechanism of psoriasis may involve platelet activation.

OBJECTIVE

The goal of the study was to establish a clearer explanation of the association between platelet activation and psoriasis activity by investigating the levels of markers of platelet activation in patients with psoriasis and examining the relationship between the marker levels and a severity score for psoriasis.

METHODS

Plasma levels of platelet-derived microparticles (PDMPs) and soluble P-selectin were measured by enzyme-linked immunosorbent assay as markers of platelet activation in 21 patients with psoriasis and 22 healthy control subjects. The relationships between the platelet activation markers and the Psoriasis Area and Severity Index score were investigated.

RESULTS

Plasma PDMPs and soluble P-selectin levels were markedly higher in patients with psoriasis compared with those in healthy control subjects. There was a significant correlation between the PDMPs levels and the Psoriasis Area and Severity Index score, and the increased plasma PDMPs and soluble P-selectin levels were markedly reduced after clinical improvement occurred.

LIMITATIONS

The number of people evaluated was relatively small.

CONCLUSIONS

Our results show that blood platelets are activated in patients with psoriasis, especially in those with extensive disease, and suggest a close association between platelet activation and psoriasis activity. Plasma PDMPs level may be a useful indicator of the severity of psoriasis.

Therapeutic leukocytapheresis in inflammatory bowel disease: clinical efficacy and mechanisms of action

Intense infiltration of the intestinal mucosa by activated leukocytes is a hallmark of inflammatory bowel disease (IBD). Therefore, removal of circulating leukocytes may be an attractive approach for treating IBD. Leukocytapheresis with Cellsorba, a column of polyethylenephtarate fibers that captures monocytes, granulocytes and lymphocytes, has been used to treat IBD, particularly ulcerative colitis, in Japan and Europe. This article reviews the clinical efficacy and safety data and the mechanisms of action of leukocytapheresis in IBD. Although the majority of clinical studies enrolled only small numbers of patients and had open-labeled designs, leukocytapheresis showed clinical efficacy with an excellent safety profile. Leukocytapheresis depletes granulocytes, monocytes, lymphocytes and platelets, alters cell population profiles, modulates cytokine production, and induces bone marrow-derived cells. In conclusion, leukocytapheresis exerts anti-inflammatory and tissue-repairing effects on the intestinal mucosa in IBD. Further studies are needed to explain the exact mechanism of action and to determine the true efficacy of this approach.

A label-free nano-liquid chromatography-mass spectrometry approach for quantitative serum peptidomics in Crohn's disease patients

The identification of serum biomarkers for the diagnosis of inflammatory bowel diseases able to reduce the need for invasive tests represents a major goal in their therapy and follow-up. We report here a methodological approach for the evaluation of specific changes in the serum peptides abundance in healthy (H) and Crohn's disease (CD) subjects, based on a label-free LC ESI/Q-TOF differential mass spectrometry (MS) approach combined with targeted MS/MS analysis. The low molecular weight serum proteins were separated by RP nano-LC ESI/Q-TOF MS and the resulting datasets were aligned with msInspect software. The differently abundant peptides, evaluated using Proteios Software Environment, were identified by MS/MS analysis and database search. The identification of clusters of peptides resulting from proteins (such as fibrinogen-alpha) commonly involved in physiological processes lead to the evaluation of a possible role in CD of specific serum exoproteases. An assay based on synthetic peptides spiked into H, CD and ulcerative colitis (UC) serum samples as substrate, followed by MALDI MS and chemometric analysis of the metabolite patterns has been developed achieving a 100% discrimination between CD, UC and H subjects. The results are promising for the application of this approach as a simple tool for diagnostic aims and biomarker discovery in CD.

Measurement of platelet-derived microparticle levels using an enzyme-linked immunosorbent assay in polymyositis and dermatomyositis patients

Platelet-derived microparticle (PDMP) levels were measured using an enzyme-linked immunosorbent assay (ELISA) to elucidate the role of platelet activation in patients with polymyositis or dermatomyositis (PM/DM). PDMP levels in active PM/DM patients (median 13.3 U/ml, interquartile range 9.9-20.7 U/ml, n = 16) and those in patients undergoing treatment (12.1 U/ml, 7.4-16.7 U/ml, n = 12) were significantly higher than in controls (6.5 U/ml, 5.0-8.4 U/ml, n = 26, vs. active, P = 0.0001; vs. treatment, P = 0.004). In a paired sampling study, PDMP decreased significantly after glucocorticoid treatment (P = 0.04). PDMP in the active PM/DM patients correlated significantly with serum C-reactive protein levels (r(s) = 0.67, P = 0.01). These results suggest that platelets may play an important role in the inflammatory process, and that PDMP level could be a useful marker of inflammatory activity in PM/DM patients. Muscle Nerve 39: 586-590, 2009.

Atorvastatin reduces plasma levels of chemokine (CXCL10) in patients with Crohn's disease

Background

In Crohn's disease high tissue expression and serum levels of chemokines and their receptors are known to correlate with disease activity. Because statins can reduce chemokine expression in patients with coronary diseases, we wanted to test whether this can be achieved in patients with Crohn's disease.

Methodology/Principal Findings

We investigated plasma levels of chemokines (CCL2, CCL4, CCL11, CCL13, CCL17, CCL22, CCL26, CXCL8, CXCL10) and endothelial cytokines (sP-selectin, sE-selectin, sICAM-3, thrombomodulin) in ten Crohn's disease patients before and after thirteen weeks' daily treatment with 80 mg atorvastatin. Of the 13 substances investigated, only CXCL10 was found to be significantly reduced (by 34%, p = 0.026) in all of the treated patients. Levels of CXCL10 correlated with C-reactive protein (r = 0.82, p<0.01).

Conclusions/Significance

CXCL10 is a ligand for the CXCR3 receptor, the activation of which results in the recruitment of T lymphocytes and the perpetuation of mucosal inflammation. Hence the reduction of plasma CXCL10 levels by atorvastatin may represent a candidate for an approach to the treatment of Crohns disease in the future.

Trial Registration

ClinicalTrials.gov NCT00454545

Unfractionated heparin and new heparin analogues from ascidians (chordate-tunicate) ameliorate colitis in rats

The anti-inflammatory effect of mammalian heparin analogues, named dermatan sulfate and heparin, isolated from the ascidian Styela plicata was accessed in a TNBS-induced colitis model in rats. Subcutaneous administration of the invertebrate compounds during a 7-day period drastically reduced inflammation as observed by the normalization of the macroscopic and histological characteristics of the colon. At the molecular level, a decrease in the production of TNF-alpha, TGF-beta, and VEGF was observed, as well as a reduction of NF-kappaB and MAPK kinase activation. At the cellular level, the heparin analogues attenuated lymphocyte and macrophage recruitment and epithelial cell apoptosis. A drastic reduction in collagen-mediated fibrosis was also observed. No hemorrhagic events were observed after glycan treatment. These results strongly indicate the potential therapeutic use of these compounds for the treatment of colonic inflammation with a lower risk of hemorrhage when compared with mammalian heparin.

Microparticle-induced release of B-lymphocyte regulators by rheumatoid synoviocytes

Introduction

In the present study, we investigated the ability of microparticles isolated from synovial fluids from patients with rheumatoid arthritis or osteoarthritis to induce the synthesis and release of key cytokines of B-lymphocyte modulation such as B cell-activating factor, thymic stroma lymphopoietin, and secretory leukocyte protease inhibitor by rheumatoid fibroblast-like synoviocytes.

Methods

Microparticles were analyzed in synovial fluids from patients with rheumatoid arthritis, osteoarthritis, microcristalline arthritis, and reactive arthritis. In addition, microparticle release after activation from various cell lines (CEM lymphocyte and THP-1 cells) was assessed. Microparticles were isolated by differential centrifugation, and quantitative determinations were carried out by prothrombinase assay after capture on immobilized annexin V. B cell-activating factor, thymic stroma lymphopoietin, and secretory leukocyte protease inhibitor release was evaluated by enzyme-linked immunosorbent assay.

Results

Microparticles isolated from synovial fluids obtained from rheumatoid arthritis and osteoarthritis patients or microparticles derived from activated THP-1 cells were able to induce B cell-activating factor, thymic stroma lymphopoietin, and secretory leukocyte protease inhibitor release by rheumatoid arthritis fibroblast-like synoviocytes. Conversely, CEM-lymphocytes-derived microparticles generated by treatment with a combination of PHA, PMA and Adt-D did not promote the release of B cell-activating factor but favored the secretion of thymic stroma lymphopoietin and secretory leukocyte protease inhibitor by rheumatoid arthritis fibrobast-like synoviocytes. However, microparticles isolated from actinomycin D-treated CEM lymphocytes were not able to induce B cell-activating factor, thymic stroma lymphopoietin, or secretory leukocyte protease inhibitor release, indicating that microparticles derived from apoptotic T cells do not function as effectors in B-cell activation.

Conclusions

These results demonstrate that microparticles are signalling structures that may act as specific conveyors in the triggered induction and amplification of autoimmunity. This study also indicates that microparticles have differential effects in the crosstalk between B lymphocytes and target cells of autoimmunity regarding the parental cells from which they derive.

Lactobacillus reuteri prevents colitis by reducing P-selectin-associated leukocyte- and platelet-endothelial cell interactions

Recent findings indicate that dextran sodium sulfate (DSS)-induced colitis is associated with a prothrombogenic phenotype, with P-selectin playing a major role in platelet recruitment. It has been suggested that probiotics may ameliorate colonic inflammation. We therefore investigated how treatment with Lactobacillus reuteri influenced P-selectin expression, leukocyte and platelet endothelial cell interactions, and colitis severity in DSS-treated rats. Rats were divided into the following four groups: nontreated, DSS treated (5% in drinking water for 9 days), L. reuteri, and L. reuteri and DSS treated. The rats were anesthetized with Inactin (120 mg/kg ip), and the dual radiolabeled monoclonal antibody technique was used to quantify P-selectin expression. Leukocyte-endothelial and platelet-endothelial cell interactions were studied in colonic venules with intravital microscopy. Colitis severity was assessed using a disease activity index. Disease activity index increased, as did the expression of P-selectin in the entire colon after DSS treatment, but both were reduced to control levels with L. reuteri pretreatment. The increased platelet- and leukocyte-endothelial cell interactions after DSS treatment were abolished by pretreatment with L. reuteri. L. reuteri protects against DSS-induced colitis in rats. The protection is associated with reduced P-selectin expression and a decrease in leukocyte- and platelet-endothelial cell interactions.

Elevated platelet activation in patients with atopic dermatitis and psoriasis: increased plasma levels of beta-thromboglobulin and platelet factor 4

BACKGROUND

Beyond their role in hemostasis and thrombosis, platelets are important for modulating inflammatory reactions. Activated platelets play a role in the pathomechanism of inflammatory diseases such as asthma, but little is known about platelet activation in chronic skin inflammation, including atopic dermatitis (AD) and psoriasis. Furthermore, the relationship between platelet activation and disease severity is not understood. This work was performed to investigate plasma levels of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4) as platelet activation markers in patients with AD or psoriasis, and to determine the relationships between these markers and disease severity.

METHODS

Plasma levels of beta-TG and PF4 were measured by enzyme-linked immunoassay in 22 healthy controls, 44 patients with AD, and 16 patients with psoriasis. The relationships between these markers and the scoring AD (SCORAD) index, blood eosinophilia, serum IgE and serum lactate dehydrogenase were investigated in AD patients, and relationships with the psoriasis area and severity index (PASI) score were examined in psoriatic patients.

RESULTS

Plasma beta-TG and PF4 levels were significantly higher in patients with AD or psoriasis compared with healthy controls. beta-TG and PF4 levels correlated with the SCORAD index, and PF4 levels correlated with PASI scores. Elevated beta-TG and PF4 levels were significantly reduced after treatments.

CONCLUSIONS

Our results show that blood platelets are activated in patients with AD or psoriasis, suggesting that activated platelets play a role in the pathomechanism of chronic skin inflammation. Furthermore, plasma beta-TG and PF4 may be markers for the severity of AD and psoriasis.

Microarray analysis of leukocytapheresis-induced changes in gene expression patterns of peripheral blood mononuclear cells in patients with ulcerative colitis

To elucidate the molecular mechanisms involved in the therapeutic effects of leukocytapheresis (LCAP), we performed microarray analysis for gene expression patterns in peripheral blood mononuclear cells (PBMCs) before and after LCAP therapy in patients with ulcerative colitis (UC). Four patients with UC were enrolled. PBMCs were isolated from peripheral venous blood obtained within 5 min before and after the first session of LCAP therapy. Cells were stimulated with IL-1beta for 12 h, and gene expression patterns were analyzed by an IntelliGene HS Human Expression Chip. The LCAP session reduced various genes, such as proinflammatory cytokines (IL-1alpha, IL-1beta, IL-6, IL-8, TNF-alpha, and IFN-gamma), cytokine receptors (IL-1R and IL-2Ralpha), chemokines, chemokine receptors, and intracellular signal transduction molecules. Genes which had increased after the LCAP session included those regulating anti-inflammatory cytokines and proteins (TGF-beta1 and IL-R antagonist), receptors for anti-inflammatory cytokines (IL-10R and IL-4R), growth factor receptors (IGF-R1, R2) and antioxidant proteins. Total changes in gene expression patterns after LCAP session were a combination of a decrease in pro-inflammatory genes and an enhancement of anti-inflammatory genes. These changes may explain some parts of the mechanisms by which LCAP improves clinical symptoms of UC patients.

Resistin is an inflammatory marker of inflammatory bowel disease in humans

OBJECTIVES

Resistin, a recently discovered adipokine, has been shown to be associated with inflammatory conditions such as insulin resistance, obesity, atherosclerosis and rheumatoid arthritis. We therefore hypothesized that (i) resistin levels may be elevated in patients with inflammatory bowel disease (IBD) and (ii) resistin levels may be associated with disease activity in IBD.

METHODS

We addressed these questions by testing for associations between resistin plasma levels, inflammatory parameters and clinical disease activity in a case-control study with 235 patients with Crohn's disease (CD), 112 patients with ulcerative colitis (UC) and 144 healthy controls.

RESULTS

Patients with IBD showed significantly higher resistin levels compared with controls (P<0.0001). In both, patients with CD and UC, resistin concentrations were significantly associated with elevated white blood cell count (P<0.0001), C-reactive protein (CRP) (P<0.0001) and disease activity (P< or =0.0001). In multivariate logistic regression analysis, resistin levels were identified as an independent predictor of active disease (odds ratio 1.014, 95% confidence interval 1.002-1.027, P=0.02) in patients with CD after adjusting for sex, age, body mass index, white blood cell count and CRP. In UC patients, resistin was associated with active disease in multivariate regression analysis after control for sex, age, body mass index and white blood cell count (odds ratio 1.015, 95% confidence interval 1.002-1.029, P=0.02). Addition of CRP, however, abolished this association.

CONCLUSION

Resistin levels are an independent predictor of disease activity in patients with CD. Resistin may represent a novel link between inflammation and IBD.

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.

Increased circulating platelet-neutrophil, platelet-monocyte complexes, and platelet activation in patients with ulcerative colitis: a comparative study

It is reported that the incidence of thromboembolism is increased in ulcerative colitis (UC), and hypercoagulability persists even when patients are in remission. We evaluated the association of inflammatory response parameters with UC activity, and activation parameters of the platelets, endothelium, and the coagulation system in UC. Eighteen UC patients and 19 healthy subjects were included in the study. The patients' clinical features were recorded down; whole blood counts and acute phase parameters were evaluated. UC patients were divided into two as active (9 patients) and inactive (9 patients) according to combined clinical activity index (CAI) and endoscopic activity index (EAI) scores. In all subjects, platelet CD62P expression, platelet-monocyte complexes (PMC), platelet-neutrophil complexes (PNC), and platelet microparticles (PMP) were determined by flow cytometry. E-selectin, thrombin-antithrombin complex (TAT) levels in plasma, and sCD40L levels in serum were determined by ELISA. In both active and inactive UC patients, platelet CD62P expression, the percentages of PMC, and PNC were significantly higher than those in the control group (P< 0.01). PMP level was higher in the control group than in inactive UC patients (P = 0.001). sCD40L level was significantly higher in active UC group than in the control group (P < 0.01). EAI score correlated significantly with PMP (r = 0.5, P = 0.04) and sCD40L (r = 0.48, P = 0.044); CAI score had a negative correlation (r = -0.68, P = 0.002) with sE-selectin level. In addition to increased CD62P expression and sCD40L, increased formation of PMC and PNC suggests a role for platelet-leukocyte complex formation together with platelet activation in thromboembolic events observed in UC.

Modulation of platelet aggregation responses by leukocytapheresis therapy in patients with active ulcerative colitis

BACKGROUND

Recent studies suggest that platelet activation plays an important role in the pathophysiology of inflammatory bowel disease. In this study, we evaluated the effects of leukocytapheresis (LCAP) on platelet functions in patients with ulcerative colitis (UC).

METHODS

Thirteen patients with active UC (five women and eight men) were treated with LCAP therapy. Platelet-rich plasma (PRP) was prepared, and platelet aggregation in response to agonist solution (epinephrine, collagen, and ADP) was measured with a platelet aggregometer. Platelet-derived microparticle (PDMP) plasma levels were determined by enzyme-linked immunosorbent assay.

RESULTS

Nine patients responded to LCAP therapy, but no clinical responses were observed in four patients. The aggregation response to 0.1 microg/ml epinephrine was enhanced in all patients. In all responders, enhanced epinephrine aggregation was normalized after the LCAP session. However, in the four nonresponders, enhanced epinephrine aggregation was maintained after the LCAP session. In responders, the mean maximum aggregation induced by 0.1 microg/ml epinephrine was 76.8 +/- 5.0% before and 15.4 +/- 3.8% after LCAP, respectively (P < 0.05). Increased aggregation responses to both 0.2 microg/ml collagen and 1.0 microM ADP were observed, and LCAP also normalized these enhanced responses. LCAP significantly reduced circulating PDMP levels (56.8 +/- 28.3 U/ml before and 46.3 +/- 30.4 U/ml after LCAP, P < 0.05).

CONCLUSIONS

LCAP reduced enhanced platelet aggregation responses in active UC patients. Because platelets play an important role in inflammatory and immune responses, therapeutic effects of LCAP may be partially mediated by reduction of increased platelet aggregation activities.