Amir Houshang Shemirani

Factor XIII and Atherothrombotic Diseases

Factor XIII (FXIII) is a protransglutaminase that, after activation, cross-links fibrin chains and several plasma proteins, most importantly alpha (2) plasmin inhibitor, to fibrin. FXIII strengthens the fibrin clot by covalent bonds and protects fibrin from the prompt elimination by the fibrinolytic system. In the last two decades, FXIII has emerged as a key regulator of fibrinolysis. FXIII is also present in platelets, monocytes, and macrophages, but this cellular form does not contribute significantly to maintaining hemostasis. FXIII deficiency is a life-threatening bleeding diathesis whose clinical consequences are well studied. In contrast, the involvement of FXIII in thrombotic disorders and its association with the risk of such diseases are less clear. This review gives an account of the data accumulated mainly in the last decade on the association of FXIII with atherothrombotic diseases and presents conclusions and hypotheses drawn from these data as well as exposing the limitations of the published studies and our knowledge on this topic. The involvement of FXIII in atherogenesis, its role in coronary artery disease, atherothrombotic ischemic stroke, and peripheral artery disease are discussed, with particular reference to the association of FXIII levels and polymorphisms with the risk of these diseases.

Rapid detection of the factor XIII Val34Leu (163 G™T) polymorphism by real-time PCR using fluorescence resonance energy transfer detection and melting curve analysis

Abstract The Val34Leu polymorphism in the A subunit of blood coagulation factor XIII (FXIII-A) is located in the activation peptide, just three amino acids upstream of the thrombin cleavage site. The Val→Leu replacement accelerates the rate of the proteolytic activation of FXIII and it seems to provide protection against myocardial infarction. Methods available for the assessment of the FXIII-A Val34Leu polymorphism are rather time-consuming, laborious and not easily applicable for large-scale studies. In this study a new method based on real-time PCR with fluorescence resonance energy transfer (FRET) detection and melting curve analysis was developed. The rapid, simple method was adapted to the widely used real-time PCR instrument, LightCycler (Roche Diagnostics). The results showed 100% coincidence with those obtained by the traditional PCR-restriction fragment length polymorphism (RFLP) assay and fluorescent DNA sequencing. Using this method, an allele frequency of 24.2% was obtained (n = 113), which well agrees with the allele frequency obtained by PCR-RFLP on a different group of the same ethnic Hungarian population (25.9%).

Factor XIII A subunit Val34Leu polymorphism in patients suffering atherothrombotic ischemic stroke

INTRODUCTION Factor XIII (FXIII) is a key regulator of fibrinolysis and clot firmness. Val34Leu polymorphism of its potentially active A subunit (FXIII-A) leads to faster activation of FXIII, influences clot structure and provides a moderate protection against coronary artery disease. The effect of FXIII A subunit (FXIII-A) Val34Leu polymorphism on the risk of ischemic stroke (IS) has been investigated in a few studies with contradictory results. In spite of their fundamental difference in pathogenesis and hemostatic pathomechanism, only four small studies investigated the effect of FXIII-A Val34Leu polymorphism on the risk of atherothrombotic IS (AIS) separately from cardioembolic IS. Gender specific effect of the polymorphism on the risk of AIS has not been explored. In the present study we investigated the effect of FXIII-A Val34Leu polymorphism on the risk of AIS on a large patient population. MATERIALS AND METHODS A population control group of 1,146 randomly selected individuals, 496 patients surviving AIS and their age and sex-matched controls selected from the population control group were included in the study. FXIII-A Val34Leu genotype was determined on DNA samples, obtained from peripheral blood leukocytes, by fluorescence resonance energy transfer detection using melting curve analysis. RESULTS Neither sex nor age affected the distribution of FXIII-A Val34Leu genotypes in population control group. No association was revealed between the risk of AIS and FXIII-A Leu34 carriership and homozygous or heterozygous presentation of Leu34 allele in either gender. CONCLUSION FXIII-A Val34Leu polymorphism fails to influence the risk of AIS.

Elevated factor XIII level and the risk of peripheral artery disease

The prothrombotic state resulting from the elevation of certain clotting factors and suppression of fibrinolysis contribute to the risk of atherothrombotic diseases. Peripheral artery disease (PAD) has been associated with elevated plasma fibrinogen concentration, increased plasminogen activator

Effect of C111T polymorphism in exon 9 of the catalase gene on blood catalase activity in different types of diabetes mellitus

Hydrogen peroxide plays a major role in the pathomechanism of diabetes mellitus and its main regulator is enzyme catalase. The blood catalase and the C111T polymorphism in exon 9 was examined in type 1, type 2 and gestational diabetes mellitus. Compared to the control group (104.7 ± 18.5 MU/l) significantly decreased (p < 0.001) blood catalase activities were detected in type 2 (71.2 ± 14.6 MU/l), gestational (68.5 ± 12.2 MU/l) diabetes mellitus and without change in type 1 (102.5 ± 26.9 MU/l). The blood catalase decreased (p = 0.043) with age for type 2 diabetics and did not change (p>0.063) for type 1, gestational diabetic patients and controls. Blood catalase showed a weak association with hemoglobin A1c for type 1 diabetic patients (r = 0.181, increasing). The mutant T allele was increased in type 1 and gestational diabetes mellitus, and CT+TT genotypes showed decreased blood catalase activity for type 1 and increased activities for type 2 diabetic patients. The C111T polymorphism may implicate a very weak effect on blood catalase activity in different types of diabetes mellitus.

The effect of metoprolol alone and combined metoprolol–felodipin on the digital microcirculation of patients with primary Raynaud's syndrome

OBJECTIVES Calcium channel inhibitors have beneficial impact on microcirculation, but beta-blocker effect is controversial. Clinicians still do not agree on beta-blocker combination with other treatments in the management of impaired microcirculation. The aim of the present study was to describe the effects of beta-blocker metoprolol monotherapy and combined with calcium channel inhibitor felodipin on digital microcirculation in primary Raynauds syndrome. METHODS We enrolled in this study 46 patients suffering from both hypertension and primary Raynauds syndrome. Fifteen patients were treated with beta-blocker monotherapy (metoprolol), 13 received combined beta-blocker and calcium channel blocker therapy (felodipin and metoprolol), while 18 patients without any medications served as controls. Measurement of digital microcirculation was carried out with laser Doppler scanner. RESULTS AND CONCLUSIONS Our investigation concludes that the concurrent administration of beta-blockers with calcium channel inhibitors positively reduces symptoms in patients suffering from Raynauds syndrome.

Increased mean platelet volume in primary Raynaud's phenomenon

We hypothesized that mean platelet volume (MPV), a reliable marker of platelet activation, might be elevated in primary Raynauds phenomenon (PRP) even if there was no thrombotic complication in our subjects. In this retrospective-cohort study, we examined the clinical value of MPV in 200 patients with PRP and 116 clinical controls, and measured MPV and platelet P-selectin (CD62P) in all study participants. We also evaluated the effect of age, gender, and disease duration on these platelet activation markers in PRP. MPV and CD62 positivities were significantly (p < 0.001) elevated in patients with PRP compared with controls. These differences retained when patients and controls were analyzed according to age, gender, and the disease duration. In logistic regression analysis, MPV (OR: 15.8, 95% CI: 8.14–30.64, p < 0.001) and CD62P (OR: 11.3, 95% CI: 4.85–26.12, p < 0.001) were found to be independently associated with PRP. In conclusion, increased MPV is independently related to PRP, and its level was not influenced by age, gender, and the duration of PRP.

Correlations between clinicopathological parameters and molecular signatures of primary tumors for patients with stage T3n0 colorectal adenocarcinomas: a single center retrospective study on 100 cases.

BACKGROUND/AIMS To examine the clinical and protein expression characteristics of tumor tissues for prediction of prognosis in colorectal cancer (CRC). METHODOLOGY We retrospectively analyzed the clinicopathological data of patients with stage T3N0 CRC, operated between 1997-2003 and the surgical materials for the relation between disease prognosis and p53, p21, p16, β-catenin, E-cadherin, EGFR, hMLH1, hMSH2 and TS protein expressions. RESULTS A significantly shorter 3-year disease free survival was observed in patients under the age of 50. The worst 5-year overall survival (OS) observed for patients over 70. Tumor localization and number of processed lymph nodes significantly affected prognosis. The EGFR, hMSH2 and TS expressions and the 5-fluorouracyl treatment were not found to be of prognostic value; p53 and p21 positivity had significantly worse survival. When β-catenin membrane expression disappeared on tumor cells, the 5-year OS rate decreased and time to metastasis shortened significantly. Membrane β-catenin expression, processed lymph nodes number and age were detected as independent prognostic markers. CONCLUSIONS These results suggest that the evaluation of a clinicopathological profile, based on age, tumor localization, number of examined lymph nodes, p53, p21 and E-cadherin β-catenin expression appears to be useful in identifying high risk patients.

Polymorphism of clotting factors in Hungarian patients with Raynaud's phenomenon

Patients with primary Raynauds phenomenon may have a genetically determined risk for clotting factors that predispose them to aberrant microvascular thrombosis. We investigated the prevalence of factor V substitution of G to A at position 1691 (FVLeiden), prothrombin G20210A, and methyltetrahydrofolate reductase C677T mutations in these patients. Two hundred (158 women, 42 men, mean age of 42.4 ± 13.7 years) consecutive patients with primary Raynauds phenomenon and 200 age-sex-matched healthy controls of Hungarian origin were included in a case–control study. The prevalence of methyltetrahydrofolate reductase C677T homozygous among patients was significantly lower than in the control group (odds ratio 0.4, 95% confidence interval 0.2–0.9, P < 0.05). The prevalence of other thrombosis-associated alleles did not differ between patients with primary Raynauds phenomenon and control subjects. FVLeiden, prothrombin G20210A, and polymorphism, prothrombin G20210A mutations have no apparent effect on the etiology of primary Raynauds phenomenon.

Prothrombotic polymorphisms in patients with Raynaud's phenomenon and migraine

We have investigated the prevalence and possible association of inherited prothrombotic risk factors in patients with primary Raynauds phenomenon (PRP) and migraine. We performed genotypic analysis of FVLeiden, prothrombin G20210A, methyltetrahydrofolate reductase C677T and FXIII-A V34L mutations in these patients. Two hundred patients with primary Raynauds phenomenon of Hungarian origin with migraine (57 female, one male, mean age of 43.8 ± 11.5 years) or without migraine (101 female, 41 male, mean age of 41.8 ± 14.5 years) were included in this study. Duration of PRP among migrainous patients was significantly longer than patients without migraine. The prevalence of methyltetrahydrofolate reductase T677 allele among patients with migraine was significantly higher than in patients without migraine (odds ratio 2.1, 95% CI: 1.4-3.3, p = 0.001). The prevalence of other thrombosis-associated alleles did not differ between patients with or without migraine. FVLeiden mutation, prothrombin G20210A mutation, and FXIII-A V34L polymorphism have no apparent effect on the occurrence of migraine in PRP.