Pathophysiological Aspects of Aging in Venous Thromboembolism: An Update

The aim of this review is to highlight all the factors that associate venous thromboembolism (VTE) with aging. Elderly people are characterized by a higher incidence of thrombosis taking into account the co-existing comorbidities, complications and fatality that arise. Based on the Virchow triad, pathophysiological aspects of venous stasis, endothelium injury and hypercoagulability in elderly people (≥65 years) are described in detail. More precisely, venous wall structure, nitric oxide (NO) and endothelin-1 expression are impaired in this age group. Furthermore, an increase in high-molecular-weight kininogen (HMWK), prekallikrein, factors V, VII, VIII, IX and XI, clot lysis time (CLT) and von Willebrand factor (vWF) is observed. Age-dependent platelet dysfunction and changes in anticoagulant factors are also illustrated. A “low-grade inflammation stage” is delineated as a possible risk factor for thrombosis in the elderly. Consequently, clinical implications for frail elderly people related to diagnosis, treatment, bleeding danger and VTE recurrence emerge. We conclude that aging is an acquired thrombotic factor closely related to pathophysiological changes.

microRNA-144/451 decreases dendritic cell bioactivity via targeting interferon-regulatory factor 5 to limit DSS-induced colitis

The microRNAs miR-144/451 are highly conserved miRNA that is strongly induced during erythropoiesis. Despite the biological functions of miR-144/451 have been extensively studied in erythropoiesis and tumorigenesis, few studies have been conducted in immune responses. In this study, we showed that miR-144/451^-/- DCs exhibit increased activation. Mechanistically, the miR-144 directly targets the 3`-UTR of IRF5 and represses the expression of IRF5 in DCs. Ectopic expression of miR-144/451 by lentiviruses downregulates the levels of IRF5 and suppresses DCs function. In addition, knockdown of IRF5 by shRNA significantly inhibits activities of the miR-144/451^-/- DCs. Expression of miR144/451 was decreased in DCs from both patients with IBD and mice with DSS-colitis compared with controls. Human PBMC derived DCs were downregulated expression of miR144/451 after LPS stimulation. In the DSS-induced colitis mice model, we showed that ablation of the miR-144/451 gene causes severe colitis, and their DCs from both periphery and MLN expressed higher co-stimulatory molecules and pro-inflammatory cytokines than wild-type mice. In addition, DCs isolated from miR-144/451^-/- mice transfusion exacerbates mice colitis. In the bone marrow transplanted chimeric mice model, we show that miR-144/451^-/- bone marrow transplantation deteriorated DSS-induced colitis. At last, we treat the mice with miR-144/451 delivered by chitosan nanoparticles revealing protective effects in DSS-induced colitis mice. Thus, our results reveal a novel miR144/451-IRF5 pathway in DCs that protects experimental colitis. The manipulation of miR-144/451 expression and DCs activation in IBD patients may be a novel therapeutic approach for the treatment of inflammatory diseases.

Cryo-EM structure of the prothrombin-prothrombinase complex

The intrinsic and extrinsic pathways of the coagulation cascade converge to a common step where the prothrombinase complex, comprising the enzyme factor Xa (fXa), the cofactor fVa, Ca2+ and phospholipids, activates the zymogen prothrombin to the protease thrombin. The reaction entails cleavage at 2 sites, R271 and R320, generating the intermediates prethrombin 2 and meizothrombin, respectively. The molecular basis of these interactions that are central to hemostasis remains elusive. We solved 2 cryogenic electron microscopy (cryo-EM) structures of the fVa-fXa complex, 1 free on nanodiscs at 5.3-Å resolution and the other bound to prothrombin at near atomic 4.1-Å resolution. In the prothrombin-fVa-fXa complex, the Gla domains of fXa and prothrombin align on a plane with the C1 and C2 domains of fVa for interaction with membranes. Prothrombin and fXa emerge from this plane in curved conformations that bring their protease domains in contact with each other against the A2 domain of fVa. The 672ESTVMATRKMHDRLEPEDEE691 segment of the A2 domain closes on the protease domain of fXa like a lid to fix orientation of the active site. The 696YDYQNRL702 segment binds to prothrombin and establishes the pathway of activation by sequestering R271 against D697 and directing R320 toward the active site of fXa. The cryo-EM structure provides a molecular view of prothrombin activation along the meizothrombin pathway and suggests a mechanism for cleavage at the alternative R271 site. The findings advance our basic knowledge of a key step of coagulation and bear broad relevance to other interactions in the blood.

Acquired Factor V Inhibitor Complicated with Immune Thrombocytopenia

We herein report a patient with a high bleeding tendency as a result of acquired factor V inhibitor and immune thrombocytopenia (ITP). The administration of prednisolone increased the platelet count, but a fatal bleeding event occurred before platelet levels had sufficiently increased. Factor V is stored in not only plasma but also platelets, and platelet-derived factor V might play a local hemostatic role. Bleeding tendency may be high in rare cases where factor V inhibitor is complicated with severe thrombocytopenia. In such patients, physicians should consider aggressive hemostatic therapy, including plasma exchange, in addition to immunosuppressive therapy.

Acquired Coagulation Factor V Inhibitor That Was Successfully Treated with Oral Corticosteroid Therapy

Acquired coagulation factor V (FV) inhibitors are rare disorders in which antibodies against FV develop under various conditions. We herein report the case of a 71-year-old woman with FV inhibitor during radiochemotherapy for pancreatic cancer. Multiple purpuras suddenly appeared on her bilateral upper limbs with prolonged coagulation data (APTT 97.3 seconds). The FV activity was less than 3% and the FV inhibitor was positive (1.7 B.U./mL). Oral prednisolone induced a rapid normalization of the coagulation data and FV activity and a rapid disappearance of FV inhibitor within 7 days. Early diagnosis and treatment may therefore be important in cases of FV inhibitor.

Structure-function of anticoagulant TIX-5, the inhibitor of factor Xa-mediated FV activation

BACKGROUND

The prothrombinase complex consists of factors Xa (FXa) and Va (FVa) on an anionic phospholipid surface and converts prothrombin into thrombin. Both coagulation factors require activation before complex assembly. We recently identified TIX-5, a unique anticoagulant tick protein that specifically inhibits FXa-mediated activation of FV. Because TIX-5 inhibited thrombin generation in blood plasma, it was concluded that FV activation by FXa contributes importantly to coagulation.

OBJECTIVE

We aimed to unravel the structure-function relationships of TIX-5.

METHOD

We used a structure model generated based on homology with the allergen Der F7.

RESULTS

Tick inhibitor of factor Xa toward FV was predicted to consist of a single rod formed by several beta sheets wrapped around a central C-terminal alpha helix. By mutagenesis we could show that two hydrophobic loops at one end of the rod mediate the phospholipid binding of TIX-5. On the other end of the rod an FV interaction region was identified on one side, whereas on the other side an EGK sequence was identified that could potentially form a pseudosubstrate of FXa. All three interaction sites were important for the anticoagulant properties of TIX-5 in a tissue factor-initiated thrombin generation assay as well as in the inhibition of FV activation by FXa in a purified system.

CONCLUSION

The structure-function properties of TIX-5 are in perfect agreement with a protein that inhibits the FXa-mediated activation on a phospholipid surface. The present elucidation of the mechanism of action of TIX-5 will aid in deciphering the processes involved in the initiation phase of blood coagulation.

[In vivo and in vitro Experiment of E74-Like Factor 5 Overexpression Inhibiting the Biological Behavior of Colon Cancer Cells]

OBJECTIVE

To investigate the effect of E74-like factor 5 (ELF5) overexpression on the growth and invasion ability of colorectal cancer cells and its effect on tumor formation in nude mice.

METHODS

Human colorectal cancer SW480 and HT-29 cells were divided into 5 groups: the lentivirus (LV)- GFP group transfected with empty vector LV- GFP, the LV- ELF5 group transfected with recombinant LV- ELF5, the shRNA-NC group transfected with empty vector shRNA-NC, the shRNA- ELF5 group transfected with recombinant shRNA- ELF5, and the control group, not transfected with any vector. Seventy-two h after transfection, the cell supernatant containing lentivirus was collected. The mRNA expression level of ELF5 in each group was examined by real-time fluorescent quantitative PCR (RT-qPCR). The protein expression levels of ELF5, apoptosis-related cleaved Caspase-3/Caspase-3 and cleaved Caspase-9/Caspase-9, and invasion-related E-cadherin and N-cadherin were checked with Western blot. CCK-8 was used to check cell viability. Colony formation experiment was done to evaluate colony formation rate. Flow cytometry was used to assess cell apoptosis. Transwell migration assay was used to examine cell invasion. TUNEL assay was used to examine the apoptosis of tissues cells. Immunohistochemistry test was done to determine the expression of E-cadherin and N-cadherin in tissues. 20 BALB/c nude mice were put into 4 groups (5 in each group): LV- GFP group, shRNA-NC group, LV- ELF5 group, and shRNA- ELF5 group. Recombinant lentiviral SW480 cell supernatants were subcutaneously injected into nude mice to construct nude mice tumorigenesis models and the volume changes of transplanted tumors were monitored. On the 30th day, transplanted tumor tissues from the nude mice were extracted and the tumor mass was measured. Western blot was done to measure the expression of ELF4 protein in the transplanted tumors. TUNEL staining was used to check cell apoptosis in the tissues, and the positive expression of N-cadherin in the transplanted tumor was measured by immunohistochemical tests.

RESULTS

Compared with the control group, there was no statistically significant difference in the indicators of the two cell lines in the LV- GFP group and shRNA-NC group. The results of Western blot and RT-qPCR showed that the ELF5 protein and mRNA of the LV- ELF5 group of the two cell lines were up-regulated ( P<0.05, compared with those of the LV- GFP group), and the ELF5 protein and mRNA of the shRNA- ELF5 group were down-regulated ( P<0.05). The ELF5 overexpression system and interference system were successfully constructed. Compared with the LV- GFP group, data from the LV- ELF5 group showed that cell viability and colony formation rate ( P<0.05) were reduced, SW480 and HT-29 cell apoptosis was promoted, cleaved Caspase-3/Caspase-3 and cleaved Caspase-9/Caspase-9 protein expression was up-regulated ( P<0.05), cell invasion was inhibited, and the expression of E-cadherin protein was up-regulated while the expression of N-cadherin protein was down-regulated ( P<0.05). After ELF5 interference, the above-mentioned expression of cells demonstrated an opposite trend ( P<0.05, comparing shRNA- ELF5 group with shRNA-NC group). In vivo experimental results indicated that ELF5 overexpression reduced tumor volume and tumor mass ( P<0.05), promoted cell apoptosis in tissues ( P<0.05), and inhibited N-cadherin protein expression ( P<0.05). When ELF5 expression was inhibited, the above mentioned experimental results showed the opposite trend.

CONCLUSION

In vivo and in vitro experiments showed that ELF5 overexpression could promote the apoptosis of colorectal cancer cells and inhibit the growth and invasion of colorectal cancer cells.

Growth-regulating factor 5 (GRF5)-mediated gene regulatory network promotes leaf growth and expansion in poplar

Although polyploid plants have larger leaves than their diploid counterparts, the molecular mechanisms underlying this difference (or trait) remain elusive. Differentially expressed genes (DEGs) between triploid and full-sib diploid poplar trees were identified from two transcriptomic data sets followed by a gene association study among DEGs to identify key leaf growth regulators. Yeast one-hybrid system, electrophoretic mobility shift assay, and dual-luciferase assay were employed to substantiate that PpnGRF5-1 directly regulated PpnCKX1. The interactions between PpnGRF5-1 and growth-regulating factor (GRF)-interacting factors (GIFs) were experimentally validated and a multilayered hierarchical regulatory network (ML-hGRN)-mediated by PpnGRF5-1 was constructed with top-down graphic Gaussian model (GGM) algorithm by combining RNA-sequencing data from its overexpression lines and DAP-sequencing data. PpnGRF5-1 is a negative regulator of PpnCKX1. Overexpression of PpnGRF5-1 in diploid transgenic lines resulted in larger leaves resembling those of triploids, and significantly increased zeatin and isopentenyladenine in the apical buds and third leaves. PpnGRF5-1 also interacted with GIFs to increase its regulatory diversity and capacity. An ML-hGRN-mediated by PpnGRF5-1 was obtained and could largely elucidate larger leaves. PpnGRF5-1 and the ML-hGRN-mediated by PpnGRF5-1 were underlying the leaf growth and development.

Coagulation factor V is a marker of tumor-infiltrating immune cells in breast cancer

Background

Factor (F) V is an essential cofactor in blood coagulation, however, F5 expression in breast tumors has also been linked to tumor aggressiveness and overall survival. The specific role of FV in breast cancer is yet unknown. We therefore aimed at dissecting the biological relevance of FV in breast cancer.

Methods

Gene expression data from a Scandinavian breast cancer cohort (n = 363) and the cancer genome atlas (TCGA) (n = 981) and 12 replication cohorts were used to search for F5 co-expressed genes, followed by gene ontology analysis. Pathological and bioinformatic tools were used to evaluate immune cell infiltration and tumor purity. T cell activation, proliferation and migration were studied in FV treated Jurkat T cells.

Results

F5 co-expressed genes were mainly associated with immune system processes and cell activation. Tumors with high expression of F5 were more infiltrated with both lymphoid (T cells, NK cells, and B cells) and myeloid cells (macrophages and dendritic cells), and F5 expression was negatively correlated with tumor purity (ρ = -0.32). Confirming a prognostic role, data from the Kaplan-Meier plotter showed that high F5 expression was associated with improved relapse-free survival. The strongest association was observed in basal-like breast cancer (HR = 0.55; 95% CI, 0.42-0.71). Exogenous FV did not substantially affect activation, proliferation or migration of human T cells.

Conclusions

F5 was identified as a novel marker of immune cell infiltration in breast cancer, and the prognostic role of F5 was verified. FV emerge as an interesting immunological biomarker with potential therapeutic relevance for the cancer-inflammation-thrombosis circuit.

Comprehensive N- and O-glycosylation mapping of human coagulation factor V

BACKGROUND/OBJECTIVE

Coagulation factor V (FV), a multidomain glycoprotein, is an essential cofactor in the blood clotting cascade. FV deficiency is a rare bleeding disorder that results in poor clotting after an injury or surgery. The only treatment for the disease is infusions of fresh frozen plasma and blood platelets. Glycosylation affects the biological activity, pharmacokinetics, immunogenicity, and in vivo clearance rate of proteins in the plasma. The glycan profile of FV, as well as how it affects the activity, stability, and immunogenicity, remains unknown.

METHODS

In this study, we comprehensively mapped the glycosylation patterns of human plasma-derived FV by combining multienzyme digestion, hydrophilic interaction chromatography enrichment of glycopeptides, and alternated fragmentation mass spectrometry analysis.

RESULTS/CONCLUSION

A total of 57 unique N-glycopeptides and 51 O-glycopeptides were identified, which were categorized into 40 N-glycan and 17 O-glycan compositions. Such glycosylation details are fundamental for future functional studies and therapeutics development. In addition, the established methodology can be readily applied to analyze glycosylation patterns of proteins with more than 2000 amino acids.

[Clinical phenotype and variantal analysis of a pedigree affected with hereditary coagulation factor V deficiency]

OBJECTIVE

To explore the molecular basis for a pedigree affected with coagulation factor V (FV) deficiency.

METHODS

Clinical data of the patient and his family members was analyzed. Targeted capture and next-generation sequencing (NGS) and Sanger sequencing were carried out to detect potential variant of the FV gene.

RESULTS

The patient presented with jaundice and prolonged prothrombin time (PT) and activated partial thromboplastic time (APTT). V factor activity measured only 0.1% of the normal level, though the patient had no sign of bleeding. A paternal heterozygous variant c.653T>C (p.F218S) and a maternal heterozygous variant c.3642_3643del (p.P1215Rfs*175) were identified in the FV gene of the patient. His elder brother was a heterozygous carrier of the c.653T>C (p.F218S) variant. c.653T>C(p.F218S) was a known pathogenic variant, while the c.3642_3643del (p.P1215Rfs*175) variant was unreported previously.

CONCLUSION

Mutations of the FV gene probably underlie the hereditary coagulation factor V deficiency in this patient. NGS combined with Sanger sequencing has detected potential variant with efficiency and provided a reliable basis for clinical and prenatal diagnosis for this family.

Improved secretion of glycoproteins using an N-glycan-restricted passport sequence tag recognized by cargo receptor

MCFD2 and ERGIC-53, which are the products of causative genes of combined factor V and factor VIII deficiency, form a cargo receptor complex responsible for intracellular transport of these coagulation factors in the early secretory pathway. In this study, using an NMR technique, we successfully identified an MCFD2-binding segment from factor VIII composed of a 10 amino acid sequence that enhances its secretion. This prompted us to examine possible effects of attaching this sequence to recombinant glycoproteins on their secretion. We found that the secretion level of recombinant erythropoietin was significantly increased simply by tagging it with the passport sequence. Our findings not only provide molecular basis for the intracellular trafficking of coagulation factors and their genetic deficiency but also offer a potentially useful tool for increasing the production yields of recombinant glycoproteins of biopharmaceutical interest.

A mathematical model of coagulation under flow identifies factor V as a modifier of thrombin generation in hemophilia A

BACKGROUND

The variability in bleeding patterns among individuals with hemophilia A, who have similar factor VIII (FVIII) levels, is significant and the origins are unknown.

OBJECTIVE

To use a previously validated mathematical model of flow-mediated coagulation as a screening tool to identify parameters that are most likely to enhance thrombin generation in the context of FVIII deficiency.

METHODS

We performed a global sensitivity analysis (GSA) on our mathematical model to identify potential modifiers of thrombin generation. Candidates from the GSA were confirmed by calibrated automated thrombography (CAT) and flow assays on collagen-tissue factor (TF) surfaces at a shear rate of 100 per second.

RESULTS

Simulations identified low-normal factor V (FV) (50%) as the strongest modifier, with additional thrombin enhancement when combined with high-normal prothrombin (150%). Low-normal FV levels or partial FV inhibition (60% activity) augmented thrombin generation in FVIII-inhibited or FVIII-deficient plasma in CAT. Partial FV inhibition (60%) boosted fibrin deposition in flow assays performed with whole blood from individuals with mild and moderate FVIII deficiencies. These effects were amplified by high-normal prothrombin levels in both experimental models.

CONCLUSIONS

These results show that low-normal FV levels can enhance thrombin generation in hemophilia A. Further explorations with the mathematical model suggest a potential mechanism: lowering FV reduces competition between FV and FVIII for factor Xa (FXa) on activated platelet surfaces (APS), which enhances FVIII activation and rescues thrombin generation in FVIII-deficient blood.

Investigation of the influence of thrombophilic genes polymorphism, including serpin 1 (pai-i), fii, prothrombin and itgb3-˩ integrin, on the frequency of stroke in association with controllable risk factors for its occurrence

OBJECTIVE

The aim is the analysis of the relationship between the polymorphism of thrombophilic genes, in particular Serpin 1 (PAI-1), F2-prothrombin and ITGB3-α integrin, and the incidence of stroke, as well as the study of factor effects of this polymorphism in association with controlled risk factors (hypertonic disease, smoking, alcohol consumption, diabetes mellitus, obesity, atrial fibrillation).

PATIENTS AND METHODS

Materials and methods: A total of 134 patients were examined (men accounted for 44.8%, women 55.2%, average age 62.5 ± 2.1). The statistical analysis was carried out using the following criteria: χ2-Pearson, Fisher's exact criterion (reversible), Chuprov's coefficient of conjugation and dispersion analysis (alternative complex).

RESULTS

Results: The relationship between the frequency of a specific allele of thrombophilia and the incidence of stroke is absent. The reason for such results can be a significant effect of random factors (hypertension, diabetes ...), a significant variability of risk factors, their different frequency in groups (inter- and intra-group differences), a significant (95%) total effect of these factors.

CONCLUSION

Conclusions:Identification of biochemical or genetic markers of thrombophilic conditions, including polymorphism of the hemostasis system genes, will significantly increase the possibility of adequate pathogenetic treatment and timely prevention of acute cerebrovascular disorders, especially persons of working age, which has great medical and social importance.

Factor V Leiden thrombophilia dental considerations

Factor V Leiden thrombophilia, a relatively common inherited type of hypercoagulability resulting from a mutation in the gene for factor V, has received minimal attention in the dental literature. This review examines related demographic information, risk factors, comorbidities, the thrombotic mechanism, clinical features, diagnostic measures, and medical management strategies. In addition, oral and maxillofacial sequelae and management guidelines are provided. If a patient is known to have the mutation, the clinician should review the patient's potential risk factors for development of thrombosis and ascertain whether any coagulation agents are currently being administered. The practitioner should be prepared to manage instances of prolonged bleeding. The dentist also should be aware of an overall increased risk of systemic thromboembolic events, particularly following head and neck trauma. Rarely, the factor V Leiden mutation has been associated with osteonecrosis of the jaw, usually concurrent with intake of sex hormones.

[Pulmonary embolism in a girl with nephrotic syndrome and factor V Leiden - case report]

Thromboembolic complications are found in 2-3% of children with nephrotic syndrome (NS); this increased risk is caused by hypovolemia, hemoconcentration, increased number and activity of platelets, hyperfibrinogenemia and loss of coagulation inhibitors. Risk is even higher in case of additional factors e.g. congenital thrombophilia.

CASE REPORT

Girl with NS aged 17 11/12 years was admitted to hospital due to respiratory tract infection with cough and back pain. NS started 9 months earlier and she had two bouts of disease, and was treated only with prednisone (current dose - 60 mg/48h). On admission she was without any abnormalities on auscultation, with BP 111/65 mmHg, HR 80 bpm, satO2 99%. Lab results showed the increase of WBC 18.3×103/μL, D-dimers 23038 μg/L and proteinuria 900 mg/dL. Other values of examined parameters were in normal limits. Chest X-ray and ECG were also normal. Presumptive diagnosis of pulmonary embolism was made and the patient was given 1000IU of antithrombin III and nadroparine (2x90IU/kg/24h s.c.). In ECHO the occlusion of left pulmonary artery and preserved blood flow in right were revealed. In angioCT clot nearly filling lumen of left pulmonary artery, clot in intermediate part of right pulmonary artery, and focus of pulmonary infarction in 10th segment of left lung were found. Doppler USG of lower limb veins did not reveal thrombi or perforator vein incompetence. Treatment with nadroparine was continued, and rapid improvement of clinical condition and disappearance of pain and cough were observed. Mycophenolate mofetil was added, which resulted in subsidence of proteinuria. Rivaroxaban was used in prophylaxis of recurrences of thromboembolism. Tests for thrombophilia revealed factor V Leiden in patient.

Basal high-sensitivity-C-reactive protein levels in patients with spontaneous venous thromboembolism

The role of C-reactive protein (CRP) in venous thromboembolism (VTE) is still under discussion because of controversial results in the literature. Conflicting data may have partly been due to bias by exogenous factors altering CRP levels. We investigated CRP concentrations in patients with spontaneous VTE applying a study design that allowed the measurement of basal high sensitivity (hs)-CRP levels. Patients with a history of deep vein thrombosis (DVT, n=117) and pulmonary embolism (PE, n=97) were compared to healthy individuals (n=104). Hs-CRP levels (mg/dl) were significantly higher in patients (n=214, median/interquartile range: 0.171/0.082–0.366) than in controls (0.099/0.053–0.245, p=0.001). The unadjusted odds ratio (OR) for VTE per 1 mg/dl increase of CRP was 2.8 [95% confidence interval (CI): 1.1–6.8, p=0.03]. This association remained significant after adjustment for factor V Leiden, prothrombin G20210A and factor VIII activity above 230% (OR = 2.9, 95% CI [1.1–7.5]), but became remarkably attenuated and lost its statistical significance after adjustment for BMI alone (OR = 1.7 [0.7–4.0]). CRP was also not independently associated with VTE in subgroups of patients (those with DVT without symptomatic PE, those with PE and patients without established risk factor) in multiple regression analysis. In summary, we observed significantly higher basal hs-CRP levels in patients with spontaneous VTE compared to healthy controls. This association was independent of hereditary and laboratory risk factors for VTE, but lost its significance after adjustment for BMI. Increased basal CRP levels do not appear to represent an independent risk factor for VTE.

Oral contraceptive use in women with poor anticoagulant response to activated protein C but not carrying the factor V Leiden mutation increases the risk of venous thrombosis

The factor V Leiden mutation (FVL), associated with reduced sensitivity to activated Protein C (APC), is a risk factor for venous thromboembolism (VTE) and displays a strong interaction with oral contraceptives (OC). The aim of this study was to evaluate the risk of VTE in OC users with reduced APC sensitivity unrelated to the FVL. APC sensitivity was measured by an original aPTT-based test (without sample pre-dilution in factor V-deficient plasma) in 195 women who suffered from VTE in reproductive age and in 487 healthy women with results being expressed as normalized ratio. Subjects with currently known clinically relevant thrombophilic alterations were excluded. APC normalized ratios were stratified into quartiles. The adjusted ORs of subjects in the lower quartile (≤0.90) was 2.46 (95%CI: 1.02–5.95). Of the 195 patients, 89 had suffered VTE during OC. The 181 healthy women who had used OC for at least 6 months in the two year period before presentation but who had stopped OC at least 3 months before blood sampling were considered OC users. The risk of VTE in subjects using OC with APC normalized ratio in the lower quartile was increased 4.9-fold (95% CI: 1.92–12.6). In conclusion, our results showed that altered APC resistance in women not carrying the FVL significantly increased the VTE risk, albeit to a lesser extent than in women also carrying the FVL. Our data also showed that OC use in women with altered APC resistance further increased the risk of VTE in a way that exceeded the additive expectation.

Risk factors for venous thrombosis in the black population

Risk factors for venous thrombo-embolism (VTE) in the black population are poorly characterized. Of 142 black cases tested a genetic cause was identified in only 9.1%: 4.2% had protein C deficiency, 2.8% protein S deficiency, 0.7% antithrombin deficiency and 1.4% were heterozygous for FV Leiden. We hypothesised that elevated factor VIII levels constitute a candidate risk factor for venous thrombosis in the black population. Factor VIII (FVIII:C) levels were determined in 100 black patients with VTE and 100 black controls in a case-control study. Of the patients 34% had a FVIII:C above 228 IU/dL (the 90thcentile value in normal blacks) compared to 10% controls. Relative to those with FVIII:C below this value, odds ratio (OR) for risk of VTE was 4.64 (95% CI 2.02-10.85). When FVIII:C below 150 IU/dL was used as a comparator, OR was 11.1 (95% CI 4.29-29.43). There was evidence for a dose-response relationship. We propose that raised FVIII:C is a major risk factor for VTE in black subjects with prevalence and odds ratio exceeding those reported for white subjects.

Polymorphisms of haemostasis genes as risk factors for preterm delivery

Clinical trials evaluating the potential benefit of anticoagulant treatment in pregnant women with inherited thrombophilia are based on the observation that a genetic predisposition to thrombosis is associated with frequent abortions and preterm birth. It was the aim of our study to delineate the impact of genetic polymorphisms with prothrombotic and antithrombotic effects on the occurrence of preterm birth in a large cohort of very-low-birth-weight (VLBW)-infants and their mothers. We examined the factor V Leiden and the prothrombin G20210A mutation, the factor VII 121del/ins and the factor XIII Val34Leu polymorphism in preterm very-low-birth-weight (VLBW, n=593) and term-born-infants (n=278) and their mothers (n=785).The primary outcome was preterm vs. term birth. From all polymorphisms tested, the maternal factor VII-121del/ins polymorphism (26.2 vs. 17.6 %; p=0.009) and the infant’s factor VII-121del/ins polymorphism (29.0 vs. 20.0 %; p=0.009) were more frequent in singletonVLBW and their mothers compared to term infants and their mothers. Furthermore, the frequency of the factor XIII-Val34Leu polymorphism was significantly lower in singleton VLBW than in term infant controls (5.1 vs. 9.6%, p=0.025). In a multivariate regression analysis, previous preterm delivery (OR=3.8, 95% CI: 1.7–8.4), the maternal carrier status of the factor-VII-121del/ins polymorphism (OR=1.7, 95% CI: 1.12–2.5, p=0.007) and the lower frequency of infant’s factor-XIII-Val34Leu polymorphism (OR=0.53; 95% CI: 0.29–0.96; p=0.038) were found to be independently associated with preterm delivery. InVLBW mothers with pathological CTG as cause of preterm delivery, the frequency of factor V Leiden mutation was significantly increased compared to VLBW mothers without pathological CTG (14.1 vs. 6.1%, p=0.01).The investigated haemostasis gene polymorphisms have a much lower impact on subsequent preterm delivery than known risk factors such as previous preterm birth. The reported association of the factor-VII-121del/ins polymorphism on preterm delivery and its clinical relevance needs to be further elucidated.

[Expression pattern of Krüpple-like factor 5 in odontoblasts]

PURPOSE

To investigate the expression of Krüpple-like factor 5 (KLF5) in human pulp-dentin complex and the function of KLF5 in differentiation and dentinogenesis of odontoblasts.

METHODS

Immunohistochemistry staining was used to investigate the expression of KLF5 in human pulp-dentin complex and dental pulp cells. Western blot was used to analyze the expression patterns of KLF5 during dental pulp cell differentiation. Significant differences between groups were evaluated using one-way ANOVA and Tukey's test with SPSS17.0 software package.

RESULTS

Immunohistochemical staining showed KLF5 was positively expressed in the odontoblasts and odontoblast-like cells, but not in dentin and predentin in both normal and carious teeth. Moreover, during mineralization of human dental pulp cells, KLF5 was primarily localized in the nuclei of dental pulp cells. Western blot showed KLF5 was significantly up-regulated during odontoblast differentiation.

CONCLUSIONS

KLF5 may play an important role in odontoblast differentiation and dentin formation.

Factor V Leiden and prothrombin G20210A mutations in young adults with cryptogenic ischemic stroke

The association between factor V Leiden (FVL) and prothrombin G20210A (PT 20210) mutations and ischemic stroke remains controversial, particularly in young adults with cryptogenic stroke. Prevalence of FVL (4.1%) and PT 20210 (8.2%) mutations was assessed in 49 patients under 50 years with cryptogenic stroke and compared with controls. Odd ratio (OR) for cryptogenic stroke was 2.62 (95% CI, 0.49-13.95) for FVL and 3.75 (95% CI, 1.05-13.34) for PT 20210 and 3.28 (95% CI, 1,17-9.20) for some recognized genetic thrombophilic defect. Moreover, the OR for cryptogenic stroke in young women using oral contraceptives (OC) was 3.59 (95% CI, 1.28-10.5). When some genetic thrombophilic defect was associated with OC, the OR was much higher (OR: 14.27; 95% CI, 0.66-309.99). Our results suggest that in the Mediterranean populations the PT 20210 mutation, but not FV Leiden, is a risk factor for cryptogenic stroke in young adults. OC use is also a significant risk factor for cryptogenic stroke, which is increased in women with some genetic thrombotic risk factor.