1,25(OH)(2)D(3) blocks TNF-induced monocytic tissue factor expression by inhibition of transcription factors AP-1 and NF-kappaB

Antiphospholipid antibodies and vitamin D deficiency in COVID-19 infection with and without venous or arterial thrombosis: A pilot case-control study

Background

Coronavirus disease-2019 (COVID-19) is associated with thromboembolism. Antiphospholipid antibody (APLa) formation is one of the mechanisms. Vitamin D deficiency has been associated with thrombosis in antiphospholipid antibody syndrome.

Objective

Measure APLa and vitamin D in hospitalized COVID-19 patients with and without thrombosis to evaluate if thromboembolism is associated with concomitant APLa and vitamin D deficiency.

Methods

Case-control study. Hospitalized COVID-19 patients with a thromboembolic event (ischemic stroke, myocardial infarction, deep venous thrombosis/pulmonary embolism, Cases n = 20). Controls (n = 20): Age, sex-matched without thromboembolic events. Patients with autoimmune disorders, antiphospholipid antibody syndrome, thrombophilia, anticoagulation therapy, prior thromboembolism, chronic kidney disease 3b, 4, end-stage renal disease, and malignancy were excluded. Given the limited current literature on the role of concomitant antiphospholipid antibodies and vitamin D deficiency in causing venous and/or arterial thrombosis in hospitalized COVID-19 patients, we enrolled 20 patients in each arm. Anti-cardiolipin IgG/IgM, beta-2 glycoprotein-1 IgG/IgM, lupus anticoagulant and vitamin D levels were measured in both groups.

Results

Cases were 5.7 times more likely to be vitamin D deficient (OR:5.7, 95% CI:1.3–25.6) and 7.4 times more likely to have any one APLa (OR:7.4, 95% CI: 1.6–49.5) while accounting for the effects of sex. Patients with both APLa and vitamin D deficiency had significantly more thrombosis compared to patients who were antibody positive without vitamin D deficiency (100% vs 47.4%; p = 0.01).

Conclusions

Thrombosis in COVID-19 was associated with concomitant APLa and vitamin D deficiency. Future studies in COVID-19 should assess the role of vitamin D in reducing thrombosis.

Does hsa-miR-223-3p from platelet-derived extracellular vesicles regulate tissue factor expression in monocytic cells?

Extracellular vesicles (EVs) released from activated platelets contain microRNAs, the most abundant of which is hsa-miR-223-3p. Endogenous hsa-miR-223-3p suppresses the expression of tissue factor (TF), the initiator of the extrinsic coagulation pathway, in endothelial cells. Monocytes can be induced to express TF to enhance coagulation, but the role of hsa-miR-223-3p in regulating monocyte TF remains unknown. This study examined whether hsa-miR-223-3p from platelet-derived EVs (pdEVs) affects TF expression in monocytes. THP-1 cells, differentiated into a monocyte-like phenotype with 1α,25-dihydroxyvitaminD3, were transfected with hsa-miR-223-3p mimic or control microRNA. Alternatively, THP-1 cells were incubated with pdEVs from PAR1-agonist peptide activated-platelets, as platelet releasate, or pdEVs isolated by ultracentrifugation. Transfection with hsa-miR-223-3p mimic resulted in significant reductions in TF protein, determined by western blotting and flow cytometry and reduced procoagulant activity, measured by a TF-specific factor Xa generation assay, compared to cells transfected with control microRNA. This reduction was reversed by co-transfection with hsa-miR-223-3p inhibitor, AntagomiR-223. Incubation of THP-1 cells with pdEVs also decreased TF expression; however, this was not reversed by AntagomiR-223. Taken together, monocyte TF expression is downregulated by hsa-miR-223-3p, but when transferred via pdEVs the effect was not reversed with Antagomir-223, suggesting other pdEV components may contribute to TF regulation.Abbreviations: Tissue factor (TF), Factor VII (FVII), activated Factor VII (FVIIa), Factor X (FX), activated Factor X (FXa), extracellular vesicles (EVs), microvesicles (MVs), platelet-derived extracellular vesicles (pdEVs), protease-activated receptor 1 agonist peptide (PAR1-AP), lipopolysaccharide (LPS), P-selectin glycoprotein ligand-1 (PSGL-1), Tris-Buffered Saline Tween (TBST), room temperature (RT)[Figure: see text].

Role of Tissue Factor in the Pathogenesis of COVID-19 and the Possible Ways to Inhibit It

COVID-19 (Coronavirus Disease 2019) is a highly contagious infection and associated with high mortality rates, primarily in elderly; patients with heart failure; high blood pressure; diabetes mellitus; and those who are smokers. These conditions are associated to increase in the level of the pulmonary epithelium expression of angiotensin-converting enzyme 2 (ACE-2), which is a recognized receptor of the S protein of the causative agent SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2). Severe cases are manifested by parenchymal lung involvement with a significant inflammatory response and the development of microvascular thrombosis. Several factors have been involved in developing this prothrombotic state, including the inflammatory reaction itself with the participation of proinflammatory cytokines, endothelial dysfunction/endotheliitis, the presence of antiphospholipid antibodies, and possibly the tissue factor (TF) overexpression. ARS-Cov-19 ACE-2 down-regulation has been associated with an increase in angiotensin 2 (AT2). The action of proinflammatory cytokines, the increase in AT2 and the presence of antiphospholipid antibodies are known factors for TF activation and overexpression. It is very likely that the overexpression of TF in COVID-19 may be related to the pathogenesis of the disease, hence the importance of knowing the aspects related to this protein and the therapeutic strategies that can be derived. Different therapeutic strategies are being built to curb the expression of TF as a therapeutic target for various prothrombotic events; therefore, analyzing this treatment strategy for COVID-19-associated coagulopathy is rational. Medications such as celecoxib, cyclosporine or colchicine can impact on COVID-19, in addition to its anti-inflammatory effect, through inhibition of TF.

Low Vitamin D Status Is Associated with Inflammation in Patients with Chronic Obstructive Pulmonary Disease

Vitamin D deficiency is associated with increased risks of chronic obstructive pulmonary disease (COPD). Nevertheless, the mechanisms remain unknown. This study analyzed the correlations between vitamin D levels and inflammation in COPD patients. One hundred and one patients with COPD and 202 control subjects were enrolled. Serum 25(OH)D level and inflammatory cytokines were detected. Serum 25(OH)D was decreased and inflammatory cytokines were increased in COPD patients. According to forced expiratory volume in 1 s, COPD patients were divided into three grades. Furthermore, serum 25(OH)D was gradually decreased in COPD patients ranging from grade 1-2 to 4. Serum 25(OH)D was inversely associated with inflammatory cytokines in COPD patients. Further analysis found that NF-κB and AP-1 signaling were activated in COPD patients. Besides, inflammatory signaling was gradually increased in parallel with the severity of COPD. By contrast, pulmonary nuclear vitamin D receptor was decreased in COPD patients. In vitro experiments showed that 1,25(OH)₂D₃ inhibited LPS-activated inflammatory signaling in A549 cells (human lung adenocarcinoma cell). Mechanically, 1,25(OH)₂D₃ reinforced physical interactions between vitamin D receptor with NF-κB p65 and c-Jun. Our results indicate that vitamin D is inversely correlated with inflammatory signaling in COPD patients. Inflammation may be a vital mediator of COPD progress in patients with low vitamin D levels.

Vitamin D receptor expression in peripheral blood mononuclear cells is inversely associated with disease activity and inflammation in lupus patients

OBJECTIVE

Systemic lupus erythematosus (SLE) is characterized by uncontrolled production of pro-inflammatory cytokines. Vitamin D receptor (VDR) has potent anti-inflammatory activities. The aim of this study was to examine the correlation between VDR expression and inflammation and disease activity in patients with SLE.

METHODS

Ninety-five SLE patients were recruited and divided into two groups, active and inactive, according to their SLE disease activity index (SLEDAI)-2 K, and 40 healthy individuals served as controls. The expression of VDR and NF-κB p65 in peripheral blood mononuclear cells (PBMCs) was determined by quantitative RT-PCR and Western blotting. VDR expression was correlated with inflammatory and diseases parameters in SLE patients. VDR regulation was also studied in THP-1 and Jurkat cell lines.

RESULTS

PBMC VDR expression was downregulated in SLE patients, especially in the active SLE group. VDR mRNA levels were negatively correlated with SLEDAI-2 K (r = - 0.348, P = 0.001), Systemic Lupus International Collaborating Clinics (SLICC) renal activity scores (r = - 0.346, P = 0.014), and proteinuria (r = - 0.309, P = 0.002) and positively associated with serum complement C3 levels (r = 0.316, P = 0.002). Multiple stepwise regression analysis indicated that PBMC VDR downregulation was an independent risk factor for SLEDAI-2 K. VDR levels were also negatively correlated with NF-κB p65 (r = - 0.339, P = 0.001), TNF-α (r = - 0.268, P = 0.009), and IL-6 (r = - 0.313, P = 0.002) levels. In monocyte and T lymphocyte cell lines, TNF-α suppressed VDR expression, whereas 1,25-dihydroxyvitamin D blocked TNF-α-induced VDR downregulation.

CONCLUSION

PBMC VDR expression is inversely associated with disease activity and inflammation in SLE patients, and VDR downregulation is likely driven by inflammation.

Venous Thromboembolism is Associated With Lack of Vitamin D Supplementation in Patients With Spinal Cord Injury and Low Vitamin D Levels

BACKGROUND

The role of vitamin D in the pathogenesis of venous thromboembolism (VTE) and prevalence of low vitamin D (LVitD) in spinal cord injury (SCI) has motivated vitamin D testing and supplementation. This is an exploratory study of data collected at a time before the routine clinical practice of vitamin D supplementation, allowing for evaluation of the natural history of vitamin D levels in patients with SCI.

OBJECTIVE

To determine if vitamin D supplementation in persons with SCI and LVitD levels is associated with decreased prevalence of VTE.

DESIGN

Retrospective cohort study.

SETTING

Rehabilitation Center at a Level I Trauma Center.

PARTICIPANTS

Patients with SCI admitted to acute inpatient rehabilitation (N = 282).

MAIN OUTCOME MEASURES

VTE prevalence in patients with LVitD levels, grouped by presence or absence of vitamin D supplementation.

RESULTS

Of the acute inpatient SCI population, 80% (227/282) of patients demonstrated vitamin D levels <30 ng/mL (LVitD). Although the incidence of VTE was almost double in the LVitD group, 19% (43/227) of the patients in the LVitD group had VTE versus 9% (5/55) of patients with vitamin D levels ≥30 ng/mL (normal VitD [NVitD]); this difference was not statistically significant (P = .108, Cramer's V = .104). When the role of vitamin D supplementation was analyzed, individuals in the LVitD group who received no vitamin D supplementation (LVitDSuppNegative) had a higher incidence of VTE (statistically significant) compared to the LVitD group with vitamin D supplementation (LVitDSuppPositive) (24% [42/178] vs. 2% [1/49]) (P < .001, Cramer's V = .226). In post hoc exploratory analyses, the VTE rate of patients in the LVitDSuppNegative group was noted to be significantly higher than that in all other patient groups combined (P < .001, Cramer's V = .229). A binary logistic regression model incorporating clinical covariates also showed this grouping to be significant.

CONCLUSION

A significant association appears to exist between lack of vitamin D supplementation and VTE occurrence in persons with acute SCI and LVitD levels.

LEVEL OF EVIDENCE

III.

Baseline Vitamin D Deficiency Decreases the Effectiveness of Statins in HIV-Infected Adults on Antiretroviral Therapy

OBJECTIVE

Vitamin D deficiency is common in HIV. Statins may increase vitamin D, and it is unknown whether vitamin D modifies the effect of statins on cardiovascular disease.

DESIGN

SATURN-HIV was a 96-week, randomized, placebo-controlled trial designed to evaluate the effect of rosuvastatin on immune activation and subclinical vascular disease in HIV-infected adults on antiretroviral therapy. This analysis focuses on the prespecified secondary endpoint 25-hydroxyvitamin D [25(OH)D] concentrations.

METHODS

Mixed effects linear modeling and analysis of variance were used to assess the rosuvastatin effect on plasma 25(OH)D concentrations over time and to determine whether baseline vitamin D modifies the rosuvastatin effect on changes in outcomes over the trial.

RESULTS

Hundred forty-seven adults were randomized (72 to rosuvastatin and 75 to placebo); 78% were men, 68% African American, with a mean age of 45 years. Baseline 25(OH)D concentrations were similar (overall mean 18 ng/mL) with 65% of participants below 20 ng/mL. Changes in 25(OH)D at 96 weeks were small and not significant within- or between-rosuvastatin and placebo groups. There were significant group by vitamin D status interactions for changes in low-density lipoprotein-cholesterol, proportion of patrolling monocytes expressing tissue factor (CD14dimCD16+TF+), lipoprotein-associated phospholipase A2, and common carotid artery intima media thickness at most time points. For each of these outcomes, the beneficial effects of rosuvastatin were either not apparent or attenuated in participants with 25(OH)D <20 ng/mL.

CONCLUSIONS

Although 25(OH)D did not change with rosuvastatin, baseline vitamin D deficiency decreased the effectiveness of rosuvastatin. Vitamin D supplementation may be warranted for deficient patients initiating statin therapy.

Vitamin D Control of Hematopoietic Cell Differentiation and Leukemia

It is now well known that in the mammalian body vitamin D is converted by successive hydroxylations to 1,25-dihydroxyvitamin D (1,25D), a steroid-like hormone with pleiotropic properties. These include important contributions to the control of cell proliferation, survival and differentiation, as well as the regulation of immune responses in disease. Here, we present recent advances in current understanding of the role of 1,25D in myelopoiesis and lymphopoiesis, and the potential of 1,25D and analogs (vitamin D derivatives; VDDs) for the control of hematopoietic malignancies. The reasons for the unimpressive results of most clinical studies of the therapeutic effects of VDDs in leukemia and related diseases may include the lack of a precise rationale for the conduct of these studies. Further, clinical trials to date have generally used extremely heterogeneous patient populations and, in many cases, small numbers of patients, generally without controls. Although low calcemic VDDs have been used and combined with agents that can increase the leukemia cell killing or differentiation effects in acute leukemias, the sequencing of agents used for combination therapy should to be more clearly delineated. Most importantly, it is recommended that in future clinical trials the rationale for the basis of the enhancing action of drug combinations should be clearly articulated and the effects on anticancer immunity should also be evaluated.

A Novel Prothrombotic Pathway in Systemic Sclerosis Patients: Possible Role of Bisphosphonate-Activated γδ T Cells

Objectives: Infusions of aminobisphonates (ABP) activate Vγ9δ2T cells in vivo and induce an acute inflammatory response in 30% of patients treated for osteoporosis. Following the observation of digital thrombosis in a systemic sclerosis (SSc) patient after treatment with an intravenous ABP, zoledronate (Zol), we evaluated whether patient and control peripheral blood (PB) mononuclear cell (MC, PBMC) acquire a prothrombotic phenotype in response to Zol.

Results: Vγ9δ2T cells of both patients and healthy donors (HD) upregulated the CD69 activation antigen and secreted tumor necrosis factor (TNF)α in response to Zol in vitro. In addition, exposure to either Zol or lipopolysaccharide (LPS), or to both additively, induced expression of the highly procoagulant, tissue factor (TF)-1 on CD14+ monocytes. Importantly, only Zol-induced TF-1 was blocked by a monoclonal antibody to TNFα. Interestingly, we found that SSc, but not HD, Vδ1+ T cells were concurrently activated by Zol to produce interleukin (IL)-4. Addition of plasma from the blood of the SSc patient who developed critical digital ischemia after infusion of Zol, but neither plasma from a second patient with no adverse clinical response to Zol infusion nor of a HD, strongly enhanced Zol-induced monocyte TF-1, which could still be blocked by anti-TNFα.

Conclusion: Aminobisphonates induced secretion of TNFα by Vγ9δ2+ T cells may lead to TNFα-dependent induction of procoagulant TF-1 induction on monocytes. In certain clinical settings, e.g., SSc, TF-1+ monocytes could play a role in triggering clinically relevant thrombosis.

Conserved steroid hormone homology converges on nuclear factor κB to modulate inflammation in asthma

Asthma is a complex, multifactorial disease comprising multiple different subtypes, rather than a single disease entity, yet it has a consistent clinical phenotype: recurring episodes of chest tightness, wheezing, and difficulty breathing (Pediatr Pulmonol Suppl. 1997;15:9-12). Despite the complex pathogenesis of asthma, steroid hormones (eg, glucocorticoids) are ubiquitous in the short-term and long-term management of all types of asthma. Overall, steroid hormones are a class of widely relevant, biologically active compounds originating from cholesterol and altered in a stepwise fashion, but maintain a basic 17-carbon, 4-ring structure. Steroids are lipophilic molecules that diffuse readily through cell membranes to directly and/or indirectly affect gene transcription. In addition, they use rapid, nongenomic actions to affect cellular products. Steroid hormones comprise several groups (including glucocorticoids, sex steroid hormones, and secosteroids) with critical divergent biological and physiological functions relevant to health and disease. However, the conserved homology of steroid hormone molecules, receptors, and signaling pathways suggests that each of these is part of a dynamic system of hormone interaction, likely involving an overlap of downstream signaling mechanisms. Therefore, we will review the similarities and differences of these 3 groups of steroid hormones (ie, glucocorticoids, sex steroid hormones, and secosteroids), identifying nuclear factor κB as a common inflammatory mediator. Despite our understanding of the impact of individual steroids (eg, glucocorticoids, sex steroids and secosteroids) on asthma, research has yet to explain the interplay of the dynamic system in which these hormones function. To do so, there needs to be a better understanding of the interplay of classic, nonclassic, and nongenomic steroid hormone functions. However, clues from the conserved homology steroid hormone structure and function and signaling pathways offer insight into a possible model of steroid hormone regulation of inflammation in asthma through common nuclear factor κB-mediated downstream events.

1α,25-Dihydroxyvitamin D(3) inhibits vascular cellular adhesion molecule-1 expression and interleukin-8 production in human coronary arterial endothelial cells

Kawasaki disease is an acute febrile vasculitis of childhood that is associated with elevated production of inflammatory cytokines, causing damage to the coronary arteries. The production of proinflammatory cytokines and expression of adhesion molecules in human coronary arterial endothelial cells (HCAECs) is regulated by nuclear transcription factor-κB (NF-κB) activation. We have previously reported that the active form of vitamin D, 1α,25-dihydroxyvitamin D(3) (1α,25-(OH)(2)D(3)), inhibits tumor necrosis factor-α (TNF-α)-induced NF-κB activation. In this study, we examined the anti-inflammatory effects of 1α,25-(OH)(2)D(3) on TNF-α-induced adhesion molecule expression (vascular cellular adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1)) and cytokine production (interleukin-6 (IL-6) and IL-8) in HCAECs. Pretreatment with 1α,25-(OH)(2)D(3) significantly inhibited TNF-α-induced VCAM-1 expression and IL-8 production in HCAECs. Our results suggest that adjunctive 1α,25-(OH)(2)D(3) therapy may modulate the inflammatory response during Kawasaki disease vasculitis.

Activation of coagulation by a thalidomide-based regimen

Combining thalidomide (Thal) with chemotherapeutic agents or steroid preparations led to improved response rates in the treatment of multiple myeloma. However, deep vein thrombosis (DVT) is one of the most serious side-effects noted with this regimen, and how a Thal-based regimen causes DVT is unclear. We investigated the procoagulant effects of Thal when combined with chemotherapeutic agents in vitro, focusing on tissue factor (TF) and phosphatidylserine. We examined the effects of the chemotherapeutic doxorubicin hydrochloride (Dox) and the steroid dexamethasone (Dex), with or without Thal. Our study used the human vascular endothelial, monocytic, and myeloma cell lines, EAhy926, THP-1, and RPMI8226, respectively. In EAhy926 and THP-1, Dex treatment increased expression of TF, which may induce procoagulant activity (PCA). Upregulation of TF mRNA correlated with activation of the Egr-1 pathway. In Thal and Dex treatments, the increase of PCA induction from phosphatidylserine exposure was modest. In contrast, Dox and Thal-Dox increased phosphatidylserine exposure in both cell types. In THP-1 cells, cell surface phosphatidylserine exposure correlated with increased PCA by Dox. Thal alone showed a modest increase in phosphatidylserine exposure in endothelial cells and monocytes. When Thal is given in combination with chemotherapies or Dex, endothelial cell and monocyte PCA may be induced through phosphatidylserine exposure, or TF expression. Induction may be protracted by Thal, which has an antiangiogenic activity. Therefore, prophylactic anticoagulant strategies should be considered in Thal-based combination regimens.

Tissue factor, blood coagulation, and beyond: an overview

Emerging evidence shows a broad spectrum of biological functions of tissue factor (TF). TF classical role in initiating the extrinsic blood coagulation and its direct thrombotic action in close relation to cardiovascular risks have long been established. TF overexpression/hypercoagulability often observed in many clinical conditions certainly expands its role in proinflammation, diabetes, obesity, cardiovascular diseases, angiogenesis, tumor metastasis, wound repairs, embryonic development, cell adhesion/migration, innate immunity, infection, pregnancy loss, and many others. This paper broadly covers seminal observations to discuss TF pathogenic roles in relation to diverse disease development or manifestation. Biochemically, extracellular TF signaling interfaced through protease-activated receptors (PARs) elicits cellular activation and inflammatory responses. TF diverse biological roles are associated with either coagulation-dependent or noncoagulation-mediated actions. Apparently, TF hypercoagulability refuels a coagulation-inflammation-thrombosis circuit in “autocrine” or “paracrine” fashions, which triggers a wide spectrum of pathophysiology. Accordingly, TF suppression, anticoagulation, PAR blockade, or general anti-inflammation offers an array of therapeutical benefits for easing diverse pathological conditions.

One unique steroidal sapogenin obtained through the microbial transformation of ruscogenin by Phytophthora cactorum ATCC 32134 and its potential inhibitory effect on tissue factor (TF) procoagulant activity

With the aim to obtain more effective tissue factor (TF) inhibitors, the microbial transformation of three steroidal sapogenins, ruscogenin (1), diosgenin (2) and sarsasapogenin (3), was carried out and only ruscogenin was selectivity converted to 1-hydroxy-spirost-4-en-3-one (4) by Phytophthora cactorum ATCC 32134. The in vitro anti-TF procoagulant activity of this metabolite was enhanced almost 10 times to an IC(50) value of 0.29 microM. The chemical assignments of compound 4 were made unambiguously using ESI-MS, IR and 2D NMR spectroscopy.

Vitamin D does not modulate NF-kappaB activity in Jurkat T cells

The active form of vitamin D, 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)], has been reported to influence the functioning of the immune system by targeting the activities of cellular signaling pathways, in addition to its direct genomic effects. One of the signaling pathways reported to be targeted by vitamin D is the NF-kappaB pathway, which is highly active in most immune cell types, including T cells. However, the effects of vitamin D on the NF-kappaB pathway in T cells are not fully understood. Therefore, we examined the effects of 1alpha,25(OH)(2)D(3) on the NF-kappaB pathway in the Jurkat cell line, a human T cell line that constitutively expresses endogenous vitamin D receptor. We found that 1alpha,25(OH)(2)D(3) does not inhibit the induction of IkappaBalpha degradation and the expression of an NF-kappaB-dependent reporter gene in Jurkat cells following treatment with PMA/ionomycin. Also, 1alpha,25(OH)(2)D(3) did not suppress the activation of NF-kappaB by TNFalpha or PHA. Furthermore, we demonstrate that 1alpha,25(OH)(2)D(3) does not block the induction of CD69, which is an NF-kappaB target gene and an early T cell activation marker. Therefore, we conclude that vitamin D does not modulate the activity of the NF-kappaB pathway in Jurkat cells.

Accelerated hepatocellular carcinoma development in mice expressing the Pim-3 transgene selectively in the liver

Pim-3, a proto-oncogene with serine/threonine kinase activity, was enhanced in hepatocellular carcinoma (HCC) tissues. To address the roles of Pim-3 in HCC development, we prepared transgenic mice that express human Pim-3 selectively in liver. The mice were born at a Mendelian ratio, were fertile and did not exhibit any apparent pathological changes in the liver until 1 year after birth. Pim-3-transgenic mouse-derived hepatocytes exhibited accelerated cell cycle progression. The administration of a potent hepatocarcinogen, diethylnitrosamine (DEN), induced accelerated proliferation of liver cells in Pim-3 transgenic mice in the early phase, compared with that observed for wild-type mice. Treatment with DEN induced lipid droplet accumulation with increased proliferating cell numbers 6 months after the treatment. Eventually, wild-type mice developed HCC with a frequency of 40% until 10 month after the treatment. Lipid accumulation was accelerated in Pim-3 transgenic mice with higher proliferating cell numbers, compared with that observed for wild-type mice. Pim-3 transgenic mice developed HCC with a higher incidence (80%) and a heavier burden, together with enhanced intratumoral CD31-positive vascular areas, compared with that observed for wild-type mice. These observations indicate that Pim-3 alone cannot cause, but can accelerate HCC development when induced by a hepatocarcinogen, such as DEN.

Tissue factor and cardiovascular disease: quo vadis?

The coagulation cascade represents a system of proteases responsible to maintain vascular integrity and to induce rapid clot formation after vessel injury. Tissue factor (TF), the key initiator of the coagulation cascade, binds to factor VIIa and thereby activates factor IX and factor X, resulting in thrombus formation. Different stimuli enhance TF gene expression in endothelial and vascular smooth muscle cells. In addition to these vascular cells, TF has recently been detected in the bloodstream in circulating cells such as leukocytes and platelets, as a component of microparticles, and as a soluble, alternatively spliced form of TF. Various cardiovascular risk factors like hypertension, diabetes, and dyslipidemia, increase levels of TF. In line with this observation, enhanced vascular TF expression occurs during atherogenesis, particularly in patients with acute coronary syndromes. (Circ J 2010; 74: 3 - 12).

Tissue factor: beyond coagulation in the cardiovascular system

TF (tissue factor) is the main trigger of the coagulation cascade; by binding Factor VIIa it activates Factor IX and Factor X, thereby resulting in fibrin formation. Various stimuli, such as cytokines, growth factors and biogenic amines, induce TF expression and activity in vascular cells. Downstream targets of these mediators include diverse signalling molecules such as MAPKs (mitogen-activated protein kinases), PI3K (phosphoinositide 3-kinase) and PKC (protein kinase C). In addition, TF can be detected in the bloodstream, known as circulating or blood-borne TF. Many cardiovascular risk factors, such as hypertension, diabetes, dyslipidaemia and smoking, are associated with increased expression of TF. Furthermore, in patients presenting with acute coronary syndromes, elevated levels of circulating TF are found. Apart from its role in thrombosis, TF has pro-atherogenic properties, as it is involved in neointima formation by inducing vascular smooth muscle cell migration. As inhibition of TF action appears to be an attractive target for the treatment of cardiovascular disease, therapeutic strategies are under investigation to specifically interfere with the action of TF or, alternatively, promote the effects of TFPI (TF pathway inhibitor).