Ljiljana Rakicevic

The use of D-dimer with new cutoff can be useful in diagnosis of venous thromboembolism in pregnancy

OBJECTIVE D-dimer testing has an important role in the exclusion of acute venous thromboembolism (VTE) in the nonpregnant population. Establishing D-dimers role in the diagnosis of VTE in pregnancy is hampered because of the substantial increase of D-dimer throughout gestational age. STUDY DESIGN In a prospective study we followed 89 healthy pregnant women to establish the reference range of D-dimer for each trimester. D-dimer testing was also performed in 12 women with clinical suspicion of VTE and their results were compared with the established new reference range of D-dimer, and with the recorded ultrasound findings. RESULTS In the first trimester, 84% women from reference group had normal D-dimer, in the second 33%, and by the third trimester only 1%, which suggests that D-dimer has no practical diagnostic use in ruling out VTE if the threshold of 230 ng/mL for abnormal is used. All pregnant women with thrombosis who had positive ultrasound findings also had statistically significant elevation of the D-dimer level, considering the established reference range of the corresponding trimester. We found 100% sensitivity of D-dimer test. A women developed thrombosis in the first trimester had 6.7-7.6 time higher level of D-dimer than the mean value in the reference group, and in the third trimester thrombotic women had 2.0-3.8 time higher level of D-dimer, p<0.0001. CONCLUSION D-dimer test with the new threshold for: the first of 286, the second of 457 and the third trimester of 644 ng/mL can be useful in diagnosis of pregnancy related VTE.

A novel role for cardiac ankyrin repeat protein Ankrd1/CARP as a co-activator of the p53 tumor suppressor protein

The muscle ankyrin repeat protein (MARP) family member Ankrd1/CARP is a part of the titin-mechanosensory signaling complex in the sarcomere and in response to stretch it translocates to the nucleus where it participates in the regulation of cardiac genes as a transcriptional co-repressor. Several studies have focused on its structural role in muscle, but its regulatory role is still poorly understood. To gain more insight into the regulatory function of Ankrd1/CARP we searched for transcription factors that could interact and modulate its activity. Using protein array methodology we identified the tumor suppressor protein p53 as an Ankrd1/CARP interacting partner and confirmed their interaction both in vivo and in vitro. We demonstrate a novel role for Ankrd1/CARP as a transcriptional co-activator, moderately up regulating p53 activity. Furthermore, we show that p53 operates as an upstream effector of Ankrd1/CARP, by up regulating the proximal ANKRD1 promoter. Our findings suggest that, besides acting as a transcriptional co-repressor, Ankrd1/CARP could have a stimulatory effect on gene expression in cultured skeletal muscle cells. It is probable that Ankrd1/CARP has a role in the propagation of signals initiated by myogenic regulatory factors (MRFs) during myogenesis.

Multi-Tasking Role of the Mechanosensing Protein Ankrd2 in the Signaling Network of Striated Muscle

Background Ankrd2 (also known as Arpp) together with Ankrd1/CARP and DARP are members of the MARP mechanosensing proteins that form a complex with titin (N2A)/calpain 3 protease/myopalladin. In muscle, Ankrd2 is located in the I-band of the sarcomere and moves to the nucleus of adjacent myofibers on muscle injury. In myoblasts it is predominantly in the nucleus and on differentiation shifts from the nucleus to the cytoplasm. In agreement with its role as a sensor it interacts both with sarcomeric proteins and transcription factors. Methodology/Principal Findings Expression profiling of endogenous Ankrd2 silenced in human myotubes was undertaken to elucidate its role as an intermediary in cell signaling pathways. Silencing Ankrd2 expression altered the expression of genes involved in both intercellular communication (cytokine-cytokine receptor interaction, endocytosis, focal adhesion, tight junction, gap junction and regulation of the actin cytoskeleton) and intracellular communication (calcium, insulin, MAPK, p53, TGF-β and Wnt signaling). The significance of Ankrd2 in cell signaling was strengthened by the fact that we were able to show for the first time that Nkx2.5 and p53 are upstream effectors of the Ankrd2 gene and that Ankrd1/CARP, another MARP member, can modulate the transcriptional ability of MyoD on the Ankrd2 promoter. Another novel finding was the interaction between Ankrd2 and proteins with PDZ and SH3 domains, further supporting its role in signaling. It is noteworthy that we demonstrated that transcription factors PAX6, LHX2, NFIL3 and MECP2, were able to bind both the Ankrd2 protein and its promoter indicating the presence of a regulatory feedback loop mechanism. Conclusions/Significance In conclusion we demonstrate that Ankrd2 is a potent regulator in muscle cells affecting a multitude of pathways and processes.

The c.-1639G>A polymorphism of the VKORC1 gene in Serbian population: retrospective study of the variability in response to oral anticoagulant therapy.

A single nucleotide polymorphism c.-1639G>A in the promoter region of vitamin K-epoxide reductase (VKORC1) gene has been found to account for most of the variability in response to oral vitamin K antagonist (VKA). Our aim was to study the effect of c.-1639G>A polymorphism on the acenocoumarol dosage requirements in a group of patients under stable anticoagulation, and to estimate the variability in response to VKA. We conducted a retrospective cohort analysis of 200 stable anticoagulation patients followed from the initiation of VKA. Out of 43 low-dose patients, 40 (93%) carried the A allele. The A allele was less frequent in the group of 30 patients requiring high VKA dose; among these patients 13 (43.3%) carried the A allele in the heterozygous form and none of them carried AA genotype. Patients with GG genotype required 2.6 times higher dose than patients carriers of AA genotype (P < 0.0001). Carriers of AA genotype were more likely to be overanticoagulated during follow-up after initiation of VKA when compared with carriers of the GA and GG genotypes (P < 0.0001). Patients with GG genotype spent more time below therapeutic range compared with patients carriers of AA (P = 0.0328) and GA genotype (P < 0.0001). VKORC1 c.-1639G>A polymorphism significantly influenced VKA dose and represented a good predictor of individuals predisposed to unstable anticoagulation. Pharmacogenetic testing could predict a high risk of overdose among 28.5% of our patients, carriers of AA genotype, before the initiation of anticoagulation.

Genetic Risk Factors for Arterial Ischemic Stroke in Children: A Possible MTHFR and eNOS Gene-Gene Interplay?

In order to investigate the influence of genetic factors in childhood stroke, we compared the distributions of mutations/ polymorphisms affecting hemostasis and/or endothelial function (factor V [FV] Leiden, factor II [FII] G20210A, methylenetetrahydrofolate reductase [MTHFR] C677T, angiotensin-converting enzyme [ACE] insertion/deletion [ID], and endothelial nitric oxide synthase [eNOS] G894T) among children with stroke and controls. A total number of 26 children with arterial ischemic stroke and a control group of 50 healthy children were included in the study. No statistically significant differences in allelic and genotypic distribution were detected in comparisons between groups. However, when combined genotypes were analyzed, statistical significance was observed for the association of MTHFR CT and eNOS TT gene variants. The results of our study suggest that this genotype combination represents a risk factor of 7.2 (P = .017) for arterial ischemic stroke in children.

Type and location of venous thromboembolism in carriers of Factor V Leiden or prothrombin G20210A mutation versus patients with no mutation.

Factor V Leiden (FVLeiden) and prothrombin G20210A are the most common genetic causes of thrombophilia and established risk factors for different clinical manifestations of venous thromboembolism (VTE). This study investigated whether the clinical manifestation of VTE, the extension of deep vein thrombosis (DVT) and the presence of transient risk factors at the time of the first VTE, differed among patients with mutations (97 with FVLeiden; 33 with prothrombin G20210A) and in 109 patients without thrombophilia. Isolated pulmonary embolism (PE) was less prevalent in patients with FVLeiden (6%) and no thrombophilia (6%) than in those with prothrombin G20210A (15%). No difference was found in the incidence of distal DVT. Regarding the extension of proximal DVT, the lowest incidence for isolated popliteal vein and the highest for iliofemoral vein were observed in patients with prothrombin G20210A. No difference was observed between groups of patients with or without thrombophilia by unprovoked VTE. The pregnancy/puerperium was the most prevalent risk factor in carriers of prothrombin G20210A. Among FVLeiden carriers, the most prevalent risk factor was surgery, and in patients without thrombophilia, it was trauma (P < .05). Thrombosis of the upper limb was more frequent in a group without thrombophilia than in patients with mutations (P < .01). Transverse sinus venous thrombosis was present only in patients with prothrombin G20210A. Carriers of prothrombin G20210A have an increased risk of developing isolated PE and more severe clinical manifestations than those with FVLeiden or without thrombophilia.

Matrix metalloproteinases gene variants in idiopathic disseminated bronchiectasis.

Background The excess of matrix metalloproteinases (MMPs) might be associated with the airways destruction or dilatation in bronchiectasis. The functional promoter polymorphisms of MMP1 and MMP9 genes, involved in the extracellular matrix remodeling, might increase the expression of MMPs leading to the development of bronchiectasis. Methods Detection of MMP1 G-1607GG and MMP9 C-1562T gene variants was performed on 37 patients with idiopathic disseminated bronchiectasis and 102 control subjects. We also described a novel method for simple and rapid detection of MMP1 G-1607GG polymorphism. Results The frequency of -1607GG allele was significantly higher in the group of patients than in control subjects (P = 0.014). The heterozygote genotype showed association with bronchiectasis (odds ratio, 5.3; 95% confidence intervals, 1.4-20.0). The association was even stronger in homozygotes for -1607GG allele (odds ration, 8.7; 95% confidence intervals, 1.9-41.0). The allelic and genotype frequencies of MMP9 C-1562T variant did not show significant differences between the groups. Conclusions This is the first report concerning a role of MMP1 G-1607GG and MMP9 C-1562T variants in pathogenesis of idiopathic disseminated bronchiectasis. The results of our study revealed the association of -1607GG allele and the lack of association of MMP9 C-1562T variant with the disease.

Does anticoagulant therapy improve pregnancy outcome equally, regardless of specific thrombophilia type?

The study was conducted to evaluate the effect of anticoagulant therapy in women with thrombophilia and to detect the possible differences among carriers of mutations (factor V [FV] Leiden and FIIG20210) and those with natural anticoagulant deficiency. The 4-year prospective investigation included 85 pregnant women, with a history of recurrent fetal loss (RFL). They were treated with prophylactic doses of low-molecular-weight heparin (nadroparin) starting from 6 to 8 weeks of gestation. Pregnancy outcomes were evaluated based on the thrombophilia type. Carriers of thrombophilic mutations had a live birth rate of 93%, compared to 41.6% for women with natural anticoagulant deficiencies. Significant differences between the groups were also observed for intrauterine fetal death, intrauterine growth restriction, and postpartum thrombosis. The optimal therapy for women with natural anticoagulant deficiency and RFL remains unclear and future prospective study with a large number of patients is required to determine the best treatment for these severe thrombophilic conditions.

Prothrombotic genetic risk factors in stroke: a possible different role in pediatric and adult patients.

The role of thrombophilia in the pathogenesis of stroke is still controversial, especially in the pediatric stroke. In order to examine the role of common thrombophilic mutations in children and adults with stroke, a case–control study was carried out in a group of 80 children and 73 younger adult patients. The control groups encompassed 100 healthy children and 120 healthy blood donors. Our results showed no significant differences in the frequency of factor V (FV) Leiden, FII G20210A, and methylenetetrahydrofolate reductase (MTHFR) C677T variants between patient groups and corresponding controls. According to our results, carriers of 677CT genotype have 3.62 higher risks to develop stroke in children than in adults (P < .001). The obtained data indicate that heterozygosity for MTHFR C677T variant represents a possible important risk factor for pediatric stroke and suggest a different role of this gene variant in etiology of stroke in pediatric and adult patients.

+1040 C/T polymorphism in coding region of thrombin-activatable fibrinolysis inhibitor gene and the risk of idiopathic recurrent fetal loss.

Recurrent fetal loss (RFL) is common health problem affecting up to 5% of women of reproductive age. It has been shown that plasma thrombin-activatable fibrinolysis inhibitor (TAFI) concentrations increase during pregnancy and return to baseline levels soon after delivery. The +1040C/T single nucleotide polymorphism in coding region of TAFI gene is associated with TAFI blood levels. The aim of our study was to investigate the relationship between +1040C/T polymorphism in TAFI gene and idiopathic RFL. Study was carried out in a group of 120 women (61 controls and 59 women with idiopathic RFL). The +1040C/T polymorphism was detected by restriction fragment length polymorphism PCR. Increased frequency of +1040T/T genotype was observed in a study group, but without statistically significant difference. Carriers of T/T genotype have increased risk of fetal loss by 1.23-fold, compared with carriers of C/C (95% CI 0.462–3.277; P = 0.7) and 1.34-fold compared with carriers of C/T genotype (95% CI 0.501–3.601; P = 0.6). C allele is associated with reduced risk of recurrent fetal loss compared with T allele (OR 0.91; 95% CI 0.545–1.533; P = 0.7). In conclusion, we observed increased frequency of +1040T/T genotype in a patient group, suggesting that this genotype could be potential risk factor for idiopathic RFL. Further investigation should be carried out in order to establish the role of this polymorphism in the etiology of idiopathic recurrent miscarriages.