OBJECTIVE: To detect the expression of autophagy components, p38 MAPK (p38) and phosphorylated forkhead box transcription factor O-1 (pFoxO1) in pulmonary vascular endothelial cells of chronic thromboembolic pulmonary hypertension (CTEPH) rats and to investigate the possible mechanism through which tissue factor (TF) regulates autophagy.
METHODS: Pulmonary artery endothelial cells (PAECs) were isolated from CTEPH (CTEPH group) and healthy rats (control group (ctrl group)) which were cocultured with TF at different time points including 12 h, 24 h, 48 h and doses including 0 nM,10 nM, 100 nM, 1µM, 10µM, 100µM and cocultured with TFPI at 48 h including 0 nM, 2.5 nM, 5 nM. The expression of forkhead box transcription factor O-1 (FoxO1), pFoxO1, p38, Beclin-1 and LC3B in PAECs was measured. Coimmunoprecipitation (co-IP) assays were used to detect the interaction between FoxO1 and LC3.
RESULTS: The protein expression of p-FoxO1/FoxO1 was significantly lower in the CTEPH groups (cocultured with TF from 0 nM to 100 µM) than in the ctrl group at 12 h, 24 h, and 48 h (P < 0.05) and was significantly lower in the CTEPH groups (cocultured with TFPI from 0 nM to 5 nM) than in the ctrl group at 48 h (P < 0.05). The protein expression of p38 in the CTEPH groups treated with 0 nM, 10 nM, 100 nM or 1 µM TF for 48 h significantly increased than ctrl groups (P < 0.05) and was significantly increased in the CTEPH groups (cocultured with TFPI concentration from 0 nM to 5 nM) than in the ctrl group at 48 h (P < 0.05). The protein expression of Beclin1 at the same concentration (cocultured with TF from 0 nM to 100 µM) was significantly lower in the CTEPH groups than ctrl groups after 24 h and 48 h (P < 0.05) and was significantly decreased in the CTEPH groups (cocultured with TFPI concentration from 2.5 nM to 5 nM) than in the ctrl group at 48 h (P < 0.05). The protein expression of LC3-II/LC3-I at the same concentration (cocultured with TF 0 nM, 1 µM, 10 µM, and 100 µM) was significantly lower in the CTEPH than in the ctrl groups after 12 h (P < 0.05) and was significantly lower in the CTEPH groups (cocultured with TFPI concentration from 0 nM to 5 nM) than in the ctrl group at 48 h (P < 0.05). There were close interactions between FoxO1 and LC3 in the control and CTEPH groups at different doses and time points.
CONCLUSIONS: The autophagic activity of PAECs from CTEPH rats was disrupted. TF, FoxO1 and p38 MAPK play key roles in the autophagic activity of PAECs. TF may regulate autophagic activity through the p38 MAPK-FoxO1 pathway.

We recently reported the potential application of recombinant prothrombin activator ecarin (RAPClot™) in blood diagnostics. In a new study, we describe RAPClot™ as an additive to develop a novel blood collection prototype tube that produces the highest quality serum for accurate biochemical analyte determination. The drying process of the RAPClot™ tube generated minimal effect on the enzymatic activity of the prothrombin activator. According to the bioassays of thrombin activity and plasma clotting, γ-radiation (>25 kGy) resulted in a 30-40% loss of the enzymatic activity of the RAPClot™ tubes. However, a visual blood clotting assay revealed that the γ-radiation-sterilized RAPClot™ tubes showed a high capacity for clotting high-dose heparinized blood (8 U/mL) within 5 min. This was confirmed using Thrombelastography (TEG), indicating full clotting efficiency under anticoagulant conditions. The storage of the RAPClot™ tubes at room temperature (RT) for greater than 12 months resulted in the retention of efficient and effective clotting activity for heparinized blood in 342 s. Furthermore, the enzymatic activity of the RAPClot™ tubes sterilized with an electron-beam (EB) was significantly greater than that with γ-radiation. The EB-sterilized RAPClot™ tubes stored at RT for 251 days retained over 70% enzyme activity and clotted the heparinized blood in 340 s after 682 days. Preliminary clinical studies revealed in the two trials that 5 common analytes (K, Glu, lactate dehydrogenase (LD), Fe, and Phos) or 33 analytes determined in the second study in the γ-sterilized RAPClot™ tubes were similar to those in commercial tubes. In conclusion, the findings indicate that the novel RAPClot™ blood collection prototype tube has a significant advantage over current serum or lithium heparin plasma tubes for routine use in measuring biochemical analytes, confirming a promising application of RAPClot™ in clinical medicine.

Coagulopathy, microvascular alterations and concomitant organ dysfunctions are hallmarks of sepsis. Attempts to attenuate coagulation activation with an inhibitor of tissue factor (TF), i.e. tissue factor pathway inhibitor (TFPI), revealed no survival benefit in a heterogenous group of sepsis patients, but a potential survival benefit in patients with an international normalized ratio (INR) < 1.2. Since an increased TF/TFPI ratio determines the procoagulant activity specifically on microvascular endothelial cells in vitro, we investigated whether TF/TFPI ratio in blood is associated with INR alterations, organ dysfunctions, disseminated intravascular coagulation (DIC) and outcome in septic shock. Twenty-nine healthy controls (HC) and 89 patients with septic shock admitted to a tertiary ICU were analyzed. TF and TFPI in blood was analyzed and related to organ dysfunctions, DIC and mortality. Patients with septic shock had 1.6-fold higher levels of TF and 2.9-fold higher levels of TFPI than HC. TF/TFPI ratio was lower in septic shock compared to HC (0.003 (0.002-0.005) vs. 0.006 (0.005-0.008), p < 0.001). Non-survivors had higher TFPI levels compared to survivors (43038 (29354-54023) vs. 28041 (21675-46582) pg/ml, p = 0.011). High TFPI levels were associated with acute kidney injury, liver dysfunction, DIC and disease severity. There was a positive association between TF/TFPI ratio and troponin T (b = 0.531 (0.309-0.754), p < 0.001). A high TF/TFPI ratio is exclusively associated with myocardial injury but not with other organ dysfunctions. Systemic TFPI levels seem to reflect disease severity. These findings point towards a pathophysiologic role of TF/TFPI in sepsis-induced myocardial injury.

UNASSIGNED: The intimal hyperplasia (IH) and vascular remodelling that follows endovascular injury, for instance after post-angioplasty re-stenosis, results in downstream ischaemia and progressive end organ damage. Interferon gamma (IFNγ) is known to play a critical role in this process. In mouse models we have previously shown that fibrocytes expressing tissue factor (TF) are recruited early to the site of injury. Through thrombin generation and protease activated receptor-1 (PAR-1) activation, fibrocytes secrete angiopoietin-2, stimulate neointimal cell proliferation, inhibit apoptosis and induce CXCL-12 production, all of which contribute to the progressive IH that then develops. In this study we investigated the relationship between TF, angiopoietin-2 and IFNγ.
UNASSIGNED: IH developing in carotid arteries of wild-type mice 4 weeks after endoluminal injury contained a significant proportion of IFNγ+ fibrocytes and macrophages, which we show, using a previously defined adoptive transfer model, were derived from circulating CD34+ cells. IH did not develop after injury in IFNγ-deficient mice, except after transplantation of WT bone marrow or adoptive transfer of WT CD34+ cells. In vitro, CD34+ cells isolated from post-injury mice did not express IFNγ, but this was induced when provided with FVIIa and FX, and enhanced when prothrombin was also provided: In both cases IFNγ secretion was TF-dependent and mediated mainly through protease activated PAR-1. IFNγ was predominantly expressed by fibrocytes. In vivo, all IFNγ+ neointimal cells in WT mice co-expressed angiopoietin-2, as did the small numbers of neointimal cells recruited in IFNγ-/- mice. Adoptively transferred WT CD34+ cells treated with either an anti-TIE-2 antibody, or with siRNA against angiopoetin-2 inhibited the expression of IFNγ and the development of IH.
UNASSIGNED: TF-dependent angiopoietin-2 production by newly recruited fibrocytes, and to a lesser extent macrophages, switches on IFNγ expression, and this is necessary for the IH to develop. These novel findings enhance our understanding of the pathophysiology of IH and expose potential targets for therapeutic intervention.

We studied the effectiveness of Xe/O2 mixture inhalation (30% Xe and 70% O2, 20 min for 5 days) in a model of experimental thromboplastin pneumonitis. Inhalation of the studied mixture decreased the intensity of the inflammatory process in the lung tissue assessed by the temperature response of animals, changed lung weight and lung weight coefficient. At acute stage of pneumonitis, an increase in xenon consumption was recorded due to its retention in the gas exchange zone and a natural decrease in oxygen consumption due to partial alveolar/capillary block. The formation of pneumonitis was accompanied by a pronounced procoagulant shift in the regulation system of the aggregate state of blood. The Xe/O2 inhalations ensured physiologically optimal levels of prothrombin and activated partial thromboplastin time against the background of a moderate decrease in fibrinogen level throughout the experiment. At the same time, the activity of the natural anticoagulant antithrombin III increased from day 5 to day 14.

Blood coagulation mediated by pig tissue factor (TF), which is expressed in pig tissues, causes an instant blood-mediated inflammatory reaction during pig-to-human xenotransplantation. Previously, we generated a soluble pig tissue factor pathway inhibitor α fusion immunoglobulin (TFPI-Ig) which inhibits pig TF activity more efficiently than human TFPI-Ig in human plasma. In this study, we generated several pig TFPI-Ig mutants and tested the efficacy of these mutants in preventing pig-to-human xenogeneic blood coagulation. Structurally important amino acid residues of pig TFPI-Ig were changed into different residues by site-directed mutagenesis. Subsequently, a retroviral vector encoding each cDNA of several pig TFPI-Ig mutants was cloned and transduced into CHO-K1 cells. After establishing stable cell lines expressing each of the pig TFPI-Ig mutants, soluble proteins were produced and purified for evaluating their inhibitory effects on pig TF-mediated blood coagulation in human plasma. The replacement of K36 and K257 with R36 and H257, respectively, in pig TFPI-Ig more efficiently blocked pig TF activity in human plasma when compared with the wild-type pig TFPI-Ig. These results may provide additional information to understand the structure of pig TFPIα, and an improved pig TFPI-Ig variant that more efficiently blocks pig TF-mediated blood coagulation during pig-to-human xenotransplantation.

Atherosclerosis, a chronic inflammatory disease, is the most relevant cause of carotid artery stenosis. Vascular endothelial cells (ECs) play a significant role in the development of atherosclerosis. In this chronic inflammatory environment, we aimed to investigate whether PCSK9 could mitigate atherosclerosis progression by reducing tissue factor expression in ECs via in vivo and in vitro assays. In vivo, we investigated the effect of PCSK9 inhibition on preventing atherosclerotic lesion formation in ApoE-/- mice fed a western diet. The results showed that inhibiting PCSK9 could significantly downregulate the protein expression of tissue factor (TF) in ECs to reduce the area of atherosclerotic plaques. In vitro, we incubated human umbilical vein endothelial cells (HUVECs) with lipopolysaccharide (LPS). We found that LPS-induced TF elevation was suppressed by a PCSK9 inhibitor at both the mRNA and protein levels and that the TLR4/NF-κB pathway was also suppressed by a PCSK9 inhibitor. With respect to plasma samples from patients with carotid artery stenosis, we also demonstrated that the expression of TF was positively correlated with that of PCSK9. Thus, in addition to regulating lipid metabolism, the regulation of endothelial cell TF expression through the TLR4/NF-κB pathway may be a potential mechanism of PCSK9 in promoting atherosclerotic carotid stenosis.

Thromboembolic events are complications in cancer patients and hypercoagulability has been linked to the tissue factor (TF) pathway, making this an attractive target. Here, we investigated the effects of chemotherapeutics and CDK inhibitors (CDKI) abemaciclib/palbociclib (CDK4/6), THZ-1 (CDK7/12/13), and dinaciclib (CDK1/2/5/9) alone and in combination regimens on TF abundance and coagulation. The human colorectal cancer (CRC) cell line HROC173 was treated with 5-FU or gemcitabine to stimulate TF expression. TF+ cells were sorted, recultured, and re-analyzed. The effect of treatment alone or in combination was assessed by functional assays. Low-dose chemotherapy induced a hypercoagulable state and significantly upregulated TF, even after reculture without treatment. Cells exhibited characteristics of epithelial-mesenchymal transition, including high expression of vimentin and mucin. Dinaciclib and THZ-1 also upregulated TF, while abemaciclib and palbociclib downregulated it. Similar results were observed in coagulation assays. The same anticoagulant activity of abemaciclib was seen after incubation with peripheral immune cells from healthy donors and CRC patients. Abemaciclib reversed 5-FU-induced TF upregulation and prolonged clotting times in second-line treatment. Effects were independent of cytotoxicity, senescence, and p27kip1 induction. TF-antibody blocking experiments confirmed the importance of TF in plasma coagulation, with Factor XII playing a minor role. Short-term abemaciclib counteracts 5-FU-induced hypercoagulation and eventually even prevents thromboembolic events.

BACKGROUND: Microparticles (MPs) have been implicated in thrombosis and endothelial dysfunction. Their involvement in early coagulopathy and in worsening of outcomes in isolated severe traumatic brain injury (sTBI) patients remains ill defined.
OBJECTIVE: We sought to quantify the circulatory MP subtypes derived from platelets (PMPs; CD42), endothelial cells (EMPs; CD62E), and those bearing tissue factor (TFMP; CD142) and analyze their correlation with early coagulopathy, thrombin generation, and in-hospital mortality.
METHODS: Prospective screening of sTBI patients was done. Blood samples were collected before blood and fluid transfusion. MP enumeration and characterization were performed using flow cytometry, and thrombin-antithrombin complex (TAT) levels were determined using enzyme-linked immunosorbent assay (ELISA). Circulating levels of procoagulant MPs were compared between isolated sTBI patients and age- and gender-matched healthy controls (HC). Patients were stratified according to their PMP, EMP, and TFMP levels, respectively (high ≥HC median and low < HC median).
RESULTS: Isolated sTBI resulted in an increased generation of PMPs (456.6 [228-919] vs. 249.1 [198.9-404.5]; P = 0.01) and EMPs (301.5 [118.8-586.7] vs. 140.9 [124.9-286]; P = 0.09) compared to HCs. Also, 5.3% of MPs expressed TF (380 [301-710]) in HCs, compared to 6.6% MPs (484 [159-484]; P = 0.87) in isolated sTBI patients. Early TBI-associated coagulopathy (TBI-AC) was seen in 50 (41.6%) patients. PMP (380 [139-779] vs. 523.9 [334-927]; P = 0.19) and EMP (242 [86-483] vs. 344 [168-605]; P = 0.81) counts were low in patients with TBI-AC, compared to patients without TBI-AC.
CONCLUSIONS: Our results suggest that enhanced cellular activation and procoagulant MP generation are predominant after isolated sTBI. TBI-AC was associated with low plasma PMPs count compared to the count in patients without TBI-AC. Low PMPs may be involved with the development of TBI-AC.

UNASSIGNED: Biomarkers to identify lung cancer (LC) patients with high risk of venous thromboembolism (VTE) are needed.
UNASSIGNED: To evaluate the usefulness of plasma tissue factor activity (TFA) and D-dimer levels for the prediction of VTE and overall survival in patients with LC.
UNASSIGNED: In a prospective multicenter observational cohort of consecutive LC patients, TFA and D-dimer levels were measured at diagnosis before any cancer treatment (V1) and between 8 and 12 weeks after diagnosis (V2).
UNASSIGNED: Among 302 patients, 38 (12.6%) experienced VTE within the first year after diagnosis. V1-TFA and V1-D-dimer levels were significantly (P = .02) higher in patients who presented VTE within 3 months than in patients without VTE: V1-TFA was 2.02 (25th-75th percentiles, 0.20-4.01) vs 0.49 (0.20-3.09) ng/mL and V1-D-dimer was 1.42 (0.64-4.40) vs 0.69 (0.39-1.53) μg/mL, respectively. Cutoffs of 1.92 ng/mL for TFA and 1.26 μg/mL for D-dimer could discriminate both groups of patients. In multivariate analysis, V1-TFA > 1.92 ng/mL was the only significant predictor of VTE risk at 1 year (hazard ratio, 2.10; 95% CI, 1.06-4.16; P = .03). V2-TFA, quantified in 251 patients, decreased significantly compared with V1-TFA (0.20 vs 0.56 ng/mL, P < .05), but a V2-TFA level > 0.77 ng/mL could predict VTE in the following 3 months. Median overall survival was worse for patients with V1-TFA > 1.92 ng/mL (14.6 vs 23.8 months) and V1-D-dimer > 1.26 μg/mL (13.8 vs 24 months, P < .001).
UNASSIGNED: High plasma TFA levels are associated with the occurrence of VTE within the next 3 months after each visit (V1 or V2) and poor survival.