An investigation of the association of the prothrombin G20210A gene mutation and inflammatory bowel disease: Factor II and 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.

Inflammatory bowel disease and thrombosis

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

Genetic evidence supporting the association of protease and protease inhibitor genes with inflammatory bowel disease: a systematic review

As part of the European research consortium IBDase, we addressed the role of proteases and protease inhibitors (P/PIs) in inflammatory bowel disease (IBD), characterized by chronic mucosal inflammation of the gastrointestinal tract, which affects 2.2 million people in Europe and 1.4 million people in North America. We systematically reviewed all published genetic studies on populations of European ancestry (67 studies on Crohn's disease [CD] and 37 studies on ulcerative colitis [UC]) to identify critical genomic regions associated with IBD. We developed a computer algorithm to map the 807 P/PI genes with exact genomic locations listed in the MEROPS database of peptidases onto these critical regions and to rank P/PI genes according to the accumulated evidence for their association with CD and UC. 82 P/PI genes (75 coding for proteases and 7 coding for protease inhibitors) were retained for CD based on the accumulated evidence. The cylindromatosis/turban tumor syndrome gene (CYLD) on chromosome 16 ranked highest, followed by acylaminoacyl-peptidase (APEH), dystroglycan (DAG1), macrophage-stimulating protein (MST1) and ubiquitin-specific peptidase 4 (USP4), all located on chromosome 3. For UC, 18 P/PI genes were retained (14 proteases and 4 protease inhibitors), with a considerably lower amount of accumulated evidence. The ranking of P/PI genes as established in this systematic review is currently used to guide validation studies of candidate P/PI genes, and their functional characterization in interdisciplinary mechanistic studies in vitro and in vivo as part of IBDase. The approach used here overcomes some of the problems encountered when subjectively selecting genes for further evaluation and could be applied to any complex disease and gene family.

A comprehensive analysis of 12 thrombophilic mutations and related parameters in patients with inflammatory bowel disease: data from Turkey

BACKGROUND

Possible association of inflammatory bowel disease (IBD) with the most common inherited prothrombotic conditions has been the focus of many investigations. Advance in modern molecular biology is expanding the thrombophilia evaluation steadily. We tried to put forward a comprehensive thrombophilic profile in IBD and to see the probable role of this profile in pathogenesis.

METHODS

A total of 60 adults (33 patients and 27 healthy controls) were included. We used the CVD-StripAssay which is based on the reverse-hybridization principle to identify a total of 12 thrombophilic gene mutations: Factor V R506Q, Factor V H1299R, prothrombin G20210A, Factor XIII V34L, beta-Fibrinogen-455 G-A, PAI-1 4G/5G, platelet GPIIIa L33P, MTHFR C677T, MTHFR A1298C, ACE I/D, Apo B R3500Q and Apo E2/E3/E4, respectively. Besides, we evaluated many related blood parameters such as protein C, protein S, AT-III, IL-6, TNF-alpha, Apo-A1, Apo-B100, homocysteine (tHcy) etc. using commercially available assays.

RESULTS

The frequencies of genetic polymorphisms were found to be statistically insignificant among patients and controls, except for three: Beta-Fibrinogen-455G-A, MTHFR A1298C and ACE-I/D. Two patients with a history of deep venous thrombosis had more than one polymorphism. Patients with MTHFR C677T and MTHFR A1298C gene mutations had a similar mean tHcy levels with controls. Patients with Apolipoprotein B R3500Q and Apolipoprotein E4 gene mutations had similar mean LDL-cholesterol levels. Mean total cholesterol and triglyceride levels were similar in patients and controls of Apo E2, E3, E4 alleles.

CONCLUSION

Predominantly, the presence of genetic mutations that predispose to hypercoagulable states does not appear to be in correlation with IBD. There was a statistical difference between the proportions of the mutated allele frequencies of Beta-Fibrinogen-455G-A, MTHFR A1298C and ACE-I/D in IBD.

Thrombosis in inflammatory bowel diseases: role of inherited thrombophilia

BACKGROUND

Inflammatory bowel diseases (IBD) are characterized by an increased risk for venous and arterial thrombosis. Although the pathogenetic mechanisms of this predisposition are unclear, a possible role of inherited risk factors for thrombosis in determining this predisposition has been suggested.

AIM

To evaluate the role of factor V Leiden (G1691A) and G20210A prothrombin gene mutations in determining the occurrence of thrombosis in IBD patients.

PATIENTS AND METHODS

Forty-seven IBD patients (30 ulcerative colitis and 17 Crohn's disease) with a positive history for thrombosis (9 at arterial sites and 38 at venous sites) were enrolled in the study. For each patient, two non-IBD subjects matched for sex and age, type, and site of thrombosis were used as controls. Peripheral blood DNA specimens were amplified by PCR using appropriate primers and analyzed by restriction analysis on agarose gel electrophoresis. Statistical analysis was performed by means of Fisher's exact test.

RESULTS

The total number of subjects with one or both mutations was significantly lower in IBD patients with thrombosis than in control subjects (12.8%vs 29.8%, respectively; p= 0.035, OR = 0.34, 95% CI 0.13-0.90). The total frequency of the mutated alleles was also significantly lower in IBD than in controls (7.4%vs 16.5%, respectively; p= 0.041, OR = 0.40, 95% CI 0.17-0.96). Prothrombotic mutations were particularly unfrequent in IBD patients with active disease at the time of thrombosis compared with patients with quiescent disease (8.0%vs 36.4%, respectively; p= 0.057, OR = 0.15, 95% CI 0.02-1.01).

CONCLUSIONS

The major inherited risk factors for thrombosis are significantly less frequent in thrombotic IBD patients than in thrombotic non-IBD subjects, suggesting that acquired risk factors play the most relevant role in determining thromboembolic events observed in IBD patients, particularly during active phases of the disease.

Venous thrombosis in inflammatory bowel disease

Patients with inflammatory bowel disease (IBD) have a threefold increased risk of venous thrombosis, a major cause of morbidity and mortality. Although the exact mechanism explaining the initiation of thrombosis remains unclear, it is likely to be a multifactorial process. Reported abnormalities include activation of markers of the coagulation cascade, disturbed fibrinolysis and the activation of platelets. The contribution of thrombophilic disorders such as factor V Leiden, prothrombin gene mutations and hyperhomocysteinaemia are discussed, but their role in thrombosis associated with IBD has remained unclear. Recent research has examined elevated CD40, P-selectin levels and tissue factor-bearing microvesicles in venous thrombosis, and the relevance of these observations to IBD is reviewed.

Prevalence of hyperhomocysteinaemia, activated protein C resistance and prothrombin gene mutation in inflammatory bowel disease

BACKGROUND

Thromboembolic disease is a significant cause of morbidity and mortality in patients with inflammatory bowel disease (IBD). A hypercoagulable state exists in IBD that may involve many components of haemostasis and is closely linked to the disease pathogenesis. It has been proposed that microvascular thrombosis and infarction may trigger the underlying inflammatory process.

AIM

To determine the prevalence of prothrombotic factors including hyperhomocysteinaemia, activated protein C (APC) resistance and prothrombin gene mutations as well as vitamin levels in the local IBD population.

METHOD

A total of 68 patients (37 men and 31 women) attending the IBD clinic were enrolled into the study. Citrated and ethylenediamine tetraacetic acid blood samples were collected from all patients as well as from 30 controls. Homocysteine levels were measured using the IMX immunoassay. APC resistance was measured using an unmodified activated partial thromboplastin time-based clotting assay. Prothrombin mutations were determined using polymerase chain reaction with the HB-gene factor II detection system.

RESULTS

Mean homocysteine levels were significantly higher and APC resistance ratios significantly lower in IBD patients compared with controls. No significant difference was detected between patients with ulcerative colitis or Crohn's disease. There was no significant increase in the incidence of prothrombin mutation in IBD patients. IBD patients had lower vitamin B12 and higher serum folate levels than controls.

CONCLUSION

High homocysteine and high serum folate may be associated with low vitamin B12 levels in IBD patients. We did not find any association between a low APC ratio and the factor V Leiden mutation or high factor VIII levels. Both hyperhomocysteinaemia and a low APC ratio may contribute to an increased risk of thromboembolic disease in IBD patients.

Review article: inherited thrombophilia in inflammatory bowel disease

Individuals with inflammatory bowel disease frequently experience increased systemic thromboembolic complications, which represent an important cause of morbidity and mortality. Risk factors for thrombosis can be inherited or acquired. The most common inherited risk factors for thromboembolism are factor V Leiden mutation, G20210A mutation in the prothrombin gene, and homozygous C677T mutation in the methylenetetrahydrofolate reductase gene. In the last few years, a great amount of literature has focused on the prevalence of such genetic mutations and their role in determining thrombosis in IBD patients. In this review, we summarize the results of these studies.