No Observed Difference in Inflammatory and Coagulation Markers Following Diets Rich in n-6 Polyunsaturated Fat vs Monounsaturated Fat in Adults With Untreated Hypercholesterolemia: A Randomized Trial

BACKGROUND

Inflammatory and prothrombotic responses are hallmark to the progression of cardiovascular disease and may be influenced by the type of dietary fat. Cottonseed oil (CSO) is rich in n-6 polyunsaturated fats and improves traditional cardiovascular disease risk factors such as cholesterol profiles. However, some clinicians are still hesitant to promote n-6 polyunsaturated fats consumption despite growing evidence suggesting they may not be independently pro-inflammatory.

OBJECTIVE

To investigate the inflammatory and coagulation marker responses to an 8-week diet intervention rich in either CSO or olive oil (OO) (OO is rich in monounsaturated fat) in adults with untreated hypercholesterolemia.

DESIGN

This was a secondary analysis of a parallel-arm randomized clinical trial with the main outcome of cholesterol measures.

PARTICIPANTS/SETTING

Participants included in this analysis were 42 sedentary adults aged 30 to 75 years (62% women) in the Athens, GA, area, between May 2018 and June 2021, with untreated hypercholesterolemia or elevated blood lipids and body mass index >18.5. Hypercholesterolemia was defined as at least two blood lipid levels in a borderline undesirable/at risk range (total cholesterol level ≥180 mg/dL, low-density lipoprotein cholesterol level ≥110 mg/dL, high-density lipoprotein cholesterol level <50 mg/dL, or triglyceride level ≥130 mg/dL), or at least one in an undesirable range (total cholesterol level ≥240 mg/dL, low-density lipoprotein cholesterol level ≥160 mg/dL, high-density lipoprotein cholesterol level <40 mg/dL, or triglyceride level ≥200 mg/dL).

INTERVENTION

Participants were randomly assigned to either the CSO or OO group in a partial outpatient feeding trial. Meals from the study provided approximately 60% of their energy needs with 30% of energy needs from either CSO or OO for 8 weeks. Participants fulfilled their remaining energy needs with meals of their choosing.

MAIN OUTCOME MEASURES

Fasting plasma concentrations of inflammatory markers, including C-reactive protein, tumor necrosis factor-α, interleukin-6, and interleukin-1β were measured at baseline and 8 weeks. Markers of coagulation potential, including plasminogen activator inhibitor-1, and tissue factor were measured at the same time points.

STATISTICAL ANALYSES PERFORMED

Repeated measures linear mixed models were used with treatment and visit in the model for analyses of all biochemical markers.

RESULTS

There were no significant differences in fasting C-reactive protein (P = 0.70), tumor necrosis factor-α (P = 0.98), interleukin-6 (P = 0.21), interleukin-1β (P = 0.13), plasminogen activator inhibitor-1 (P = 0.29), or tissue factor (P = 0.29) between groups across the intervention.

CONCLUSIONS

Inflammation and coagulation marker responses to diets rich in CSO vs OO were not significantly different between groups, and neither group showed changes in these markers in adults with untreated hypercholesterolemia. This provides additional evidence suggesting that dietary n-6 polyunsaturated fats may not promote inflammation compared with monounsaturated fatty acids, even in adults at increased risk for cardiovascular disease.

Scurvy

Dear Editor, Scurvy is a nutritional disorder which can develop after prolonged (>1-3 months) severe vitamin C deficiency. Vitamin C is a cofactor in several enzyme reactions involved in collagen synthesis. The defect in collagen causes blood vessel fragility, poor wound healing, mucocutaneous bleedings, hair abnormalities, bone pains, and joint contractures due to periosteal and intraarticular bleeding (1,2). Risk factors for scurvy development are undernutrition, low socioeconomic status, older age, male sex, alcoholism, tobacco smoking, and severe psychiatric illnesses (1-3). The required daily intake for vitamin C is ~60 mg, and this amount of vitamin C can be found in only one medium-sized orange. For this reason, the disease is rarely encountered in developed countries and is often underrecognized by healthcare personnel. Herein, we present an illustrative case of scurvy in order to raise the awareness of this disorder. A 61-year-old Caucasian man was admitted to hospital due to fatigue, hypotension (80/50 mmHg), severe normocytic anemia (hemoglobin 76 g/L), kidney failure (estimated glomerular filtration rate of 6 mL/min/1.73m2) and mild elevation in C-reactive protein (30.9 mg/L). Prior medical history included radical cystoprostatectomy with an ileal conduit performed eight years ago due to a bladder tumor and moderate chronic kidney disease with recurrent urinary tract infections. The patient was also an alcoholic and tobacco smoker, with a very low-income and a poor diet. He did not use any medications. Heteroanamnestically, the current clinical state had developed slowly over several weeks. At admission, the patient was afebrile, lethargic, malnourished, and immobile due to generalized weakness, bone pains, and hip and knee contractures. He had generalized edema, mostly related to kidney failure, as well as severe hypoalbuminemia (serum albumin 19 g/L). There were multiple ecchymoses (Figure 1, a) and perifollicular bleedings (Figure 1, b) in the skin. The teeth were defective, and the patient's facial hair had a "corkscrew" appearance (Figure 1, c). The platelet count was normal, as was the serum fibrinogen level and the prothrombin- and activated partial thromboplastin times. Vancomycin-resistant Enterococcus faecium and multi-drug-resistant Acinetobacter baumanii were isolated from the urine. Therefore, hemodialysis, linezolid, and colistin were started. However, the patient continued to be lethargic, immobile, and with prominent skin bleeding. Medical workup excluded the possibility of an underlying malignancy or an autoimmune disorder. Finally, scurvy was suspected and 500 mg daily of oral vitamin C was introduced into therapy. In the following two weeks, the general condition of the patient significantly improved and he was discharged from the hospital in good condition - mobile and with complete resolution of skin lesions (Figure 1, d and e). Three months later, the patient was still under maintenance hemodialysis and had mild anemia (hemoglobin 123 g/L). Interestingly, scurvy was the first disease in the history of medicine for which a randomized trial found a cure (4). The differential diagnosis of scurvy includes skin infections, hematologic disorders, collagen vascular disorders, and anticoagulant/antiplatelet side-effects (1). Pathognomonic skin findings which may help raise suspicion of scurvy are perifollicular bleedings and "corkscrew" hair. Notably, laboratory testing for vitamin C concentration is not necessary to confirm scurvy as it tends to reflect recent dietary intake of vitamin C (2). Nevertheless, it may be useful to identify less typical cases (2). In our case, rapid clinical improvement with the resolution of skin lesions and joint contractures after the introduction of vitamin C confirmed the clinical diagnosis of scurvy. Additionally, vitamin C deficiency could be, at least partly (besides kidney failure and acute infection), responsible for severe anemia at disease presentation (5). This case serves to remind clinicians not to forget scurvy when treating patients at risk for vitamin C deficiency who present with fatigue, anemia, bone pains, and unexplained mucocutaneous bleedings. In suspected cases, vitamin C should be administered without hesitation.

Clinical laboratory parameters and fatality of Severe fever with thrombocytopenia syndrome patients: A systematic review and meta-analysis

Background

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne infectious disease with high case fatality rate. Unfortunately, no vaccine or antiviral specifically targeting SFTS virus (SFTSV) are available for the time being. Our objective was to investigate the association between clinical laboratory parameters and fatality of SFTS patients.

Methods

The systematic review was conducted in accordance with The Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. We searched (from inception to 24th February 2022) Web of Science, PubMed, National Knowledge Infrastructure databases and Wan Fang Data for relevant researchers on SFTS. Studies were eligible if they reported on laboratory parameters of SFTS patients and were stratified by clinical outcomes. A modified version of Newcastle-Ottawa scale was used to evaluate the quality of included studies. Standardized mean difference (SMD) was used to evaluate the association between laboratory parameters and outcomes. The between-study heterogeneity was evaluated quantitatively by standard Chi-square and the index of heterogeneity (I2). Heterogeneity was explored by subgroup and sensitivity analyses, and univariable meta-regression. Publication bias was determined using funnel plots and Egger’s test.

Results

We identified 34 relevant studies, with over 3300 participants across three countries. The following factors were strongly (SMD>1 or SMD<-0.5) and significantly (P<0.05) associated mortality: thrombin time (TT) (SMD = 1.53), viral load (SMD = 1.47), activated partial-thromboplastin time (APTT) (SMD = 1.37), aspartate aminotransferase (AST) (SMD = 1.19), lactate dehydrogenase (LDH) (SMD = 1.13), platelet count (PLT) (SMD = -0.47), monocyte percentage (MON%) (SMD = -0.47), lymphocyte percentage (LYM%) (SMD = -0.46) and albumin (ALB) (SMD = -0.43). Alanine aminotransferase, AST, creatin phosphokinase, LDH, PLT, partial-thromboplastin time and viral load contributed to the risk of dying of SFTS patients in each subgroup analyses. Sensitivity analysis demonstrated that the results above were robust.

Conclusions/significance

The abnormal levels of viral load, PLT, coagulation function and liver function, significantly increase the risk of SFTS mortality, suggesting that SFTS patients with above symptoms call for special concern.

Virus-Inspired Gold Nanorod-Mesoporous Silica Core-Shell Nanoparticles Integrated with tTF-EG3287 for Synergetic Tumor Photothermal Therapy and Selective Therapy for Vascular Thrombosis

Synergetic therapy includes the combination of two or more conventional therapeutic approaches and can be used for tumor treatment by combining the advantages and avoiding the drawbacks of each type of treatment. In the present study, truncated tissue factor (tTF)-EG3287 fusion protein-encapsulated gold nanorod (GNR)-virus-inspired mesoporous silica core-shell nanoparticles (vinyl hybrid silica nanoparticles; VSNP) (GNR@VSNP-tTF-EG3287) were synthesized to achieve synergetic therapy by utilizing selective vascular thrombosis therapy (SVTT) and photothermal therapy (PTT). By integrating the targeted coagulation activity of tTF-EG3287 and the high tumor ablation effect of GNR@VSNP, local hyperthermia could induce a high percentage of apoptosis of vascular endothelial cells by using near-infrared light. This provided additional phospholipid sites for tTF-EG3287 and enhanced its procoagulant activity in vitro. In addition, the nanoparticles, which had unique topological viral structures, exhibited superior cellular uptake properties leading to significant antitumor efficacy. The in vivo antitumor results further demonstrated an interaction between SVTT and PTT, whereas the synergetic therapy (SVTT and PTT) achieved an enhanced effect, which was superior to the respective treatment efficacy of each modality or the additive effect of their individual efficacies. In summary, the synthesized GNR@VSNP-tTF-EG3287 exerted synergetic effects and enhanced the antitumor efficiency by avoiding multiple injections and suboptimal administration. These effects simultaneously affected both tumor blood supply and cancer cell proliferation. The data suggested that the integration of SVTT induced by tTF-EG3287 and PTT could provide potential strategies for synergetic tumor therapy.

A comparison of red blood cell transfusion utilization between anti-activated factor X and activated partial thromboplastin monitoring in patients receiving unfractionated heparin

Essentials Anti-activated factor X (Anti-Xa) monitoring is more precise than activated partial thromboplastin (aPTT). 20 804 hospitalized cardiovascular patients monitored with Anti-Xa or aPTT were analyzed. Adjusted transfusion rates were significantly lower for patients monitored with Anti-Xa. Adoption of Anti-Xa protocols could reduce transfusions among cardiovascular patients in the US.

SUMMARY

Background Anticoagulant activated factor X protein (Anti-Xa) has been shown to be a more precise monitoring tool than activated partial thromboplastin time (aPTT) for patients receiving unfractionated heparin (UFH) anticoagulation therapy. Objectives To compare red blood cell (RBC) transfusions between patients receiving UFH who are monitored with Anti-Xa and those monitored with aPTT. Patients/Methods A retrospective cohort study was conducted on patients diagnosed with acute coronary syndrome (ACS) (N = 14 822), diagnosed with ischemic stroke (STK) (N = 1568) or with a principal diagnosis of venous thromboembolism (VTE) (N = 4414) in the MedAssets data from January 2009 to December 2013. Anti-Xa and aPTT groups were identified from hospital billing details, with both brand and generic name as search criteria. Propensity score techniques were used to match Anti-Xa cases to aPTT controls. RBC transfusions were identified from hospital billing data. Multivariable logistic regression was used to identify significant drivers of transfusions. Results Anti-Xa patients had fewer RBC transfusions than aPTT patients in the ACS population (difference 17.5%; 95% confidence interval [CI] 16.4-18.7%), the STK population (difference 8.2%; 95% CI 4.4-11.9%), and the VTE population (difference 4.7%; 95% CI 3.3-6.1%). After controlling for patient age and gender, diagnostic risks (e.g. anemia, renal insufficiency, and trauma), and invasive procedures (e.g. cardiac catheterization, hemodialysis, and coronary artery bypass graft), Anti-Xa patients were less likely to have a transfusion while hospitalized for ACS (odds ratio [OR] 0.16, 95% CI 0.14-0.18), STK (OR 0.41, 95% CI 0.29-0.57), and VTE (OR 0.35, 95% CI 0.26-0.48). Conclusion Anti-Xa monitoring was associated with a significant reduction in RBC transfusions as compared with aPTT monitoring alone.

[Arginine-glycine-aspartic polypeptide mediated truncated tissue factor therapy for colorectal carcinoma]

OBJECTIVE

To explore the therapy effects of (arginine-glycine-aspartic, RGD)(3)-truncated tissue factor (tTF) fusion protein on colorectal carcinoma in mice.

METHODS

The (RGD)(3)-tTF fusion gene, constructed with tTF and three series-wound peptides RGD, was expressed in Escherichia coli BL21 (DE(3)). The fusion protein was purified through Nickel affinity chromatography column. The coagulation activity of the (RGD)(3)-tTF fusion protein was detected by clotting assay in vitro. Mice colorectal cancer cells line CT26 were inoculated subcutaneously into mice to establish colorectal cancer model. Four mice were randomly divided into two groups to be injected with the (RGD)(3)-tTF or tTF fusion protein labeled with rhodamine B isothiocyanate (RBITC) at a single dose of 50 microg respectively. The location of the (RGD)(3)-tTF fusion protein in the colorectal carcinoma bearing mice tissue was analyzed by using in vivo optical imaging one hour after the injection and confocal microscopy twenty-four hours after the injection. Fifteen mice bearing colorectal carcinoma were randomly divided into three groups for injection with the (RGD)(3)-tTF, tTF fusion protein or phosphate buffered saline (PBS) at a single dose of 50 microg respectively. The tumor size was measured daily to calculate the tumor volume. Five days after the injection, the mice were killed to harvest tumor tissues, hearts, livers, spleens, lung, kidneys and brains to observe valid thrombogenesis and tumor necrosis.

RESULTS

With the concentration of the (RGD)(3)-tTF fusion protein increased, the clotting time was shorten correspondingly under the conditions of Ca(2+), and the clotting time was (8.6 +/- 0.2) min when the concentration was 6 micromol/L, and it was >30 min in the group of 0 micromol/L (P < 0.05). The coagulation activity of (RGD)(3)-tTF and tTF fusion protein was alike (F = 0.09, P > 0.05). The in vivo optical imaging and confocal microscopy analyses showed that RBITC fluorescence labeling (RGD)(3)-tTF fusion protein was assembled in the tumor vasculature. On the first, third, fifth day after injection, the tumor volume of (RGD)(3)-tTF fusion protein group was (120.8 +/- 4.8) mm(3), (93.8 +/- 3.4) mm(3), (132.2 +/- 7.7) mm(3) respectively, which was significantly smaller than that of the tTF group [(181.4 +/- 13.8) mm(3), (333.0 +/- 32.0) mm(3), (514.0 +/- 11.5) mm(3)] and PBS group [(182.6 +/- 11.5) mm(3), (332.8 +/- 21.0) mm(3), (524.2 +/- 16.7) mm(3)] (both P < 0.05). However, there was no significant difference in the tumor volume between the latter two groups (P > 0.05).

CONCLUSION

The (RGD)(3)-tTF fusion protein is capable of targeting to tumor vasculature and inducing thrombogenesis for suppressing the tumor growth in the colorectal carcinoma mice model, and it's expected to be a new therapy for colorectal cancer.

Tissue factor and factor VIIa as therapeutic targets in disorders of hemostasis

For hemophilia patients with inhibitors against FVIII or FIX, the development of recombinant factor VIIa (rFVIIa) raises the possibility of a therapeutic alternative whose availability and convenience of treatment are comparable to those of FVIII or FIX. In support of this new concept for the treatment of bleeding episodes, pharmacological doses of FVIIa have been shown to induce hemostasis. Pharmacological doses of rFVIIa enhance thrombin generation on thrombin-activated platelets, thereby facilitating the formation of strong, well-structured fibrin plugs resistant to premature proteolysis. Modified rFVIIa molecules with a stronger hemostatic potential have been produced. Inhibition of the FVII-TF-dependent pathway (TFPI and rFVIIai) has been tried in attempts to prevent thrombosis, with promising results in animal models so far not confirmed in clinical trials.

[The changes of general potential of hemocoagulation in children, suffering an acute hematogenic osteomyelitis]

Chronometric hypocoagulation was observed in children, suffering an acute hematogenic ostheomyelitis, witnessed by processes of thrombin formation according to internal (the prolonged time of the blood plasm recalcification and activated partial thromboplastin time) and external (the thrombin time enhancement) ways of the blood coagulation process, as well as changes in fibrinogenesis mechanisms (the thrombin time prolongation). The lowering of anticoagulant capacity of the blood (the antithrombin III activity inhibition by 18.5%) was combined with significant increase of the thrombocytes functional activity (the rising of their adhesive and aggregational properties) in more than two times, which have occurred on the background of constant content of fibrinogen in the blood. Changes in the system of the plasm fibrinolysis in an acute hematogenic ostheomyelitis was characterized by inhibition of cofermental and, mainly, fermental fibrinolytic activity of the blood plasm, in conjunction with Hageman-dependent fibrinolysis intensification and was accompanied by accumulation of soluble complexes of fibrin-monomer in the blood. So far, chronometric hypocoagulation is secondary process, caused by the influence of soluble complexes of fibrin-monomer, which blocks fibrinogenesis. That's why the general potential of the blood coagulation system in children with an acute hematogenic ostheomyelitis must be regarded as a structural hypercoagulation.

Tissue Factor in Cardiovascular Diseases

Tissue factor (TF), formerly known as thromboplastin, is the key initiator of the coagulation cascade; it binds factor VIIa resulting in activation of factor IX and factor X, ultimately leading to fibrin formation. TF expression and activity can be induced in endothelial cells, vascular smooth muscle cells, and monocytes by various stimuli such as cytokines, growth factors, and biogenic amines. These mediators act through diverse signal transduction mechanisms including MAP kinases, PI3-kinase, and protein kinase C. Cellular TF is present in three pools as surface, encrypted, and intracellular protein. TF can also be detected in the bloodstream, referred to as circulating or blood-borne TF. Elevated levels of TF are observed in patients with cardiovascular risk factors such as hypertension, diabetes, dyslipidemia, and smoking as well as in those with acute coronary syndromes. TF may indeed be involved in the pathogenesis of atherosclerosis by promoting thrombus formation; in addition, it can induce migration and proliferation of vascular smooth muscle cells. As a consequence, therapeutic strategies have been developed to specifically interfere with the action of TF such as antibodies against TF, site-inactivated factor VIIa, or recombinant TF pathway inhibitor. Inhibition of TF action appears to be an attractive target for the treatment of cardiovascular diseases.

Inhibition of tumor growth by RGD peptide-directed delivery of truncated tissue factor to the tumor vasculature

Selective activation of blood coagulation in tumor vessels with subsequent tumor infarction is a promising anticancer strategy. To this end, a fusion protein consisting of the extracellular domain of tissue factor [truncated tissue factor (tTF)] was fused to the peptide GRGDSP selectively targeting alpha(v)-integrins on tumor endothelial cells. tTF-RGD retained its thrombogenic and integrin-binding activity in vitro. In vivo studies in mice bearing human adenocarcinomas (CCL185), melanoma (M21), and fibrosarcoma (HT1080) revealed that i.v. administration of tTF-RGD induced thrombotic occlusion of tumor vessels resulting in tumor growth retardation or regression in all three types of solid tumors. No apparent side effects, such as thrombosis, in other organs or other treatment-related toxicities were observed. Reduced tumor blood flow in tTF-RGD-treated animals as determined by contrast-enhanced magnetic resonance imaging underlines the proposed mechanism. In conclusion, we consider RGD peptide-directed delivery of tTF as alternative to previously used antibody fusion proteins. Small peptide-directed delivery of coaguligands does not cause immunologic side effects and those caused by accumulation in the reticuloendothelial system. This is the first report to describe the induction of selective thrombosis in tumor vessels by RGD peptide-directed delivery of tTF, which may be a promising strategy for the treatment of cancer.

Sinus grafting using recombinant human tissue factor, platelet-rich plasma gel, autologous bone, and anorganic bovine bone mineral xenograft: histologic analysis and case reports

PURPOSE

The purpose of this study was to analyze healthy bone formation by means of histology and immunohistochemistry after grafting with a mixture of autologous ground calvarial bone, inorganic xenograft, platelet-rich plasma (PRP), and recombinant human tissue factor (rhTF).

MATERIALS AND METHODS

Maxillary sinus floor augmentation was performed on 3 patients by grafting with 5 to 10 mL of a paste consisting of autologous powder from calvarial bone (diameter < 1 mm), 50% v/v anorganic bovine bone mineral xenograft (PepGen P-15, a new tissue-engineered bone replacement graft material), PRP (1.8 x 10(6) platelets/mm3 plasma), and about 1 microg rhTF. Six and 10 months after grafting, bone cores were extracted for implant fixation and analyzed.

RESULTS

Histology demonstrated a high degree of inorganic xenograft integration and natural bone regeneration. Both the xenograft and newly synthesized bone were colonized with osteocytes and surrounded by osteoblasts. Six-month-old bone cores demonstrated a ratio of synthesized bone to xenograft particles ratio of 0.5, whereas 10-month-old cores demonstrated a ratio of 2. A low degree of inflammation could also be observed using S100A8 immunohistochemistry.

DISCUSSION

Autologous grafting in edentulous patients is a complex procedure; the successful substitution of synthetic analogs for ground bone is a major challenge.

CONCLUSION

In this investigation, it was shown that inorganic xenograft in the harvested bone paste could be safe for patients and had high bone regeneration capacity over time. The sinus graft showed intense bone formation 6 months after grafting and a further increase in bone growth 10 months after grafting.

Comparison of three different targeted tissue factor fusion proteins for inducing tumor vessel thrombosis

Tissue Factor (TF) is a cell membrane receptor protein that is the initiator of the extrinsic pathway of the blood coagulation cascade and normally released from damaged tissues. By substituting the attachment site with a tumor delivery agent, this potent thrombogenic protein in its truncated form (tTF) can be targeted to the tumor where it can initiate clotting, thereby occluding the tumor's blood supply and causing rapid tumor destruction. To test the therapeutic potential of this vascular targeting approach, three fusion proteins, chTNT-3/tTF, chTV-1/tTF, and RGD/tTF, which target DNA exposed in degenerative areas of tumors, fibronectin on the tumor vascular basement membrane, and alpha nu beta 3 on the luminal side of tumor vessels, respectively, were developed and tested for their antitumor effects. Antigen binding and clotting assays demonstrated that each of the fusion proteins retained their antigen binding and thrombogenic activities. In vivo studies in mice bearing established MAD109 lung and Colon 26 carcinomas revealed that all three reagents induced histological evidence of microregional thrombosis and massive cell necrosis. Of interest, the chTV-1/tTF and RGD/tTF fusion proteins induced thrombosis in small and medium sized tumor vessels, whereas the chTNT-3/tTF induced clotting in relatively larger vessels. Treatment studies showed that chTNT-3/tTF and chTV-1/tTF but not RGD/tTF had a significant inhibition of tumor growth. These studies demonstrate that multiple targets exist which can be used to localize tTF to occlude tumor vessels in two diversely different murine tumor models. To attain a significant antitumor effect, however, these thrombogenic agents had to occlude medium and large vessels within the tumor. Additional studies are warranted to identify maximal conditions for inducing therapeutic vascular coagulation as a new and potent method of cancer therapy.

Tissue factor pathway inhibitors as a novel approach to antithrombotic therapy

Tissue factor is the initiator of the extrinsic pathway of the coagulation cascade. It is expressed by endothelial cells when stimulated by cytokines and other mediators. The effect of tissue factor is physiologically balanced by tissue factor pathway inhibitor. Atherosclerotic plaques are rich in tissue factor. It stimulates thrombus formation when plaques rupture. The emerging role of tissue factor in cellular signaling and in the pathogenesis of atherosclerosis has directed attention to inhibitors of tissue factor as a new antithrombotic approach. In comparison to currently used anticoagulants, tissue factor pathway inhibitors have the potential advantage of inhibiting the coagulation cascade at its earliest stage. These agents also act locally at the site of endothelial injury with minimal disturbance of systemic hemostasis. In addition, their inhibitory effect on neointimal formation and restenosis after vascular intervention are appealing features in the management of the complications of atherosclerosis.

Recombinant nematode anticoagulant protein c2, an inhibitor of the tissue factor/factor VIIa complex, in patients undergoing elective coronary angioplasty

OBJECTIVES

We investigated the safety and pharmacodynamics of escalating doses of recombinant nematode anticoagulant protein c2 (rNAPc2) in patients undergoing elective coronary angioplasty.

BACKGROUND

Recombinant NAPc2 is a potent inhibitor of the tissue factor/factor VIIa complex, which has the potential to reduce the risk of thrombotic complications in coronary artery disease.

METHODS

In a randomized, double-blinded, dose-escalation, multicenter trial, 154 patients received placebo or rNAPc2 at doses of 3.5, 5.0, 7.5, and 10.0 microg/kg body weight as a single subcutaneous administration 2 to 6 h before angioplasty. All patients received aspirin, unfractionated heparin during angioplasty, and clopidogrel in case of stent implantation.

RESULTS

Minor bleeding rates for the doses 3.5 to 7.5 microg/kg were comparable to that with placebo (6.7%), whereas an incidence of 26.9% was observed at the 10.0 microg/kg dose level (p < 0.01). Major bleedings occurred in the 5.0 microg/kg (n = 3) and 7.5 microg/kg (n = 1) dose groups. The three patients in the 5.0 microg/kg dose group also received a glycoprotein IIb/IIIa receptor inhibitor at the moment of major bleeding. Systemic thrombin generation, as measured by prothrombin fragment 1+2 (F(1+2)), was suppressed in all rNAPc2 dose groups to levels below pretreatment values for at least 36 h. In the placebo group, a distinct increase of F(1+2) levels was observed following cessation of heparin.

CONCLUSIONS

Inhibition of the tissue factor/factor VIIa complex with rNAPc2, at doses up to 7.5 microg/kg, in combination with aspirin, clopidogrel, and unfractionated heparin appears to be a safe and effective strategy to prevent thrombin generation during coronary angioplasty.

Human recombinant tissue factor, platelet-rich plasma, and tetracycilne induce a high-quality human bone graft: a 5-year survey

PURPOSE

To increase human bone graft regeneration and quality by the use of a mixture containing autologous ground calvarial bone, human recombinant tissue factor (rhTF), platelet-rich plasma (PRP), and tetracycline.

MATERIALS AND METHODS

Maxillary sinus floor augmentation was performed on 18 patients by grafting a "bone paste" made of PRP (1.8 x 10(6) platelets/mm3 plasma), about 1 microg rhTF, calvarial bone chips (2 to 5 mm in size), and tetracycline (10 to 30 microg/mL preparation). Five to 6 months after the surgical phase and grafting a bone core was extracted for implant fixation, and the osseous core samples were analyzed microscopically.

RESULTS

Histology revealed vascularized connective tissue rich in lamellar bone spicules containing osteocytes and surrounded by osteoblasts. The success rate of grafting was 90.3%. In 6-month postoperative blood samples, no residual coagulating disturbances could be found.

DISCUSSION

The combination of calvarial bone chips, rhTF, PRP, and tetracycline results in a paste that is easy to handle, safe for patients, and possesses high bone-regeneration capacity.

CONCLUSION

The generalized use in implant dentistry, oral surgery, and orthopedics of such a protocol could facilitate the healing process as well as patient safety and surgeon comfort.

Soluble tissue factor induces coagulation on tumor endothelial cells in vivo if coadministered with low-dose lipopolysaccharides

OBJECTIVE

This study was performed to evaluate the mechanisms leading to tumor vessel occlusion by tissue factor-based drugs, which are used in vascular targeting approaches for the treatment of malignant tumors.

METHODS AND RESULTS

The effects of nontargeted soluble tissue factor were evaluated in vitro and in vivo. Tumor-bearing mice were treated with (1) the extracellular portion of tissue factor (soluble tissue factor), (2) low nontoxic doses of lipopolysaccharides, or (3) a combination thereof. The combination treatment showed the best effects and resulted in selective thrombosis of tumor vessels. On the basis of our data from subsequent in vitro analyses, including surface plasmon resonance measurements and endothelial cell based coagulation assays, we propose a model on how soluble tissue factor, although lacking its membrane anchor, can promote selective tumor vessel occlusion.

CONCLUSIONS

To our knowledge, this is the first report to describe the molecular mechanisms of coagulation induction by untargeted soluble tissue factor in vivo. Combination treatments including soluble tissue factor might represent an alternative vascular targeting approach for the treatment of malignant tumors.

Immunotherapy of metastatic kidney cancer

From April 1986 to September 2000, 122 MRCC patients were treated by monthly intralymphatic injections (containing a mean of 573 IL-2 U and 26 x 10(6) LAK cells) and i.m. administration of IFN and TF; 71 patients also received a 3-day cycle of monthly IL-2 inhalations with a mean of 998 daily U. MRCC cases not treated by immunotherapy (n = 89) represent our historical controls. Adverse clinical side effects related to treatment were negligible. CR (n = 11) and PR (n = 13) were noticed in 24/122 patients. Of 24 responding patients, 17 resumed progression, whereas 7 remain in remission 11-69 months later. The overall median survival of treated patients (28 months) was 3.5-fold higher than the median survival of historical controls (7.5 months), and a Kaplan-Meier curve showed 25% survival 11 years after the beginning of immunotherapy. Apparently, the addition of IL-2 by inhalation improved survival. The present immunotherapy protocol appears to be efficacious, safe, devoid of adverse side effects, far less costly than others and able to offer a good quality of life to MRCC patients; if confirmed in a multicenter trial, it could set the basis for developing low-dose immunomodulatory treatments.

Monitoring therapy with vitamin K antagonists in patients with lupus anticoagulant: effect on different tests for INR determination

BACKGROUND

Lupus anticoagulant (antiphospholipid antibodies) is associated with venous and arterial thrombosis in patients with and without autoimmune disorders. Vitamin K antagonists are the treatment of choice in patients with thrombosis, of which the dose is titrated by INR monitoring. Several recent reports suggest that the presence of the lupus anticoagulant disturbs the INR test and may lead to unreliable results with a large variation in INR values, dependent on the reagents used.

METHODS

We studied 11 lupus anticoagulant positive patients and 11 lupus anticoagulant negative patients, all using vitamin K antagonists. The INR value was determined using seven different tests and the variation in INR values was compared between the two groups. The amidolytic Factor X levels were used as an phospholipid independent measure for intensity of warfarin therapy. Factor VII and X activity were measured to assess the stability of warfarin therapy.

RESULTS

The variation of the results with different INR tests within one patient was minimal and comparable in the two groups for INR's in the therapeutic range. The coefficient of variation for the cases and control group was 10.43 and 9.35, respectively. Variation in both groups increased at supratherapeutic levels of anticoagulation and when the anticoagulation was unstable (measured with Factor X/Factor VII ratio). The relationship between INR values and Factor X analysis revealed no influence of the lupus anticoagulant.

CONCLUSIONS

In this study, lupus anticoagulant antibodies do not disturb INR laboratory tests. Differences in INR measurements are seen in patients with a high intensity of anticoagulation and in patients who either just started or in whom no stable anticoagulation has been achieved. Abbreviated Abstract. This study investigates the influence of lupus anticoagulant on INR determination tests in patients treated with warfarin. Eleven cases and eleven lupus anticoagulant negative control patients, also on warfarin therapy, were included. Seven INR results per patient were obtained using different laboratory tests. A factor X assay was performed to obtain an independent measure for the intensity of warfarin therapy. The variation of INR results between the cases and controls revealed no difference in these groups. In addition, the relationship between INR values and Factor X analysis indicated no influence of the lupus anticoagulant. What was observed was an increased difference in INR values in patients with a high intensity of anticoagulation and in patients who either just started or in whom no stable anticoagulation has been achieved

Histopathological findings in experimental aneurysms embolized with conventional and thrombogenic/antithrombolytic Guglielmi coils

We studied the short- and long-term histological responses induced by conventional and modified electronically detachable coils (GDCs) in experimental aneurysms. Eighteen carotid bifurcation aneurysms were produced microsurgically in rabbits. Six animals each were treated either with conventional or with GDCs coated with a mixture of tissue-thromboplastin to enhance intra-aneurysmal thrombus formation and of plasminogen activator inhibitor type-1 (PAI-1) in inhibit intra-aneurysmal clot fibrinolysis. Six served as untreated controls. Follow-up angiograms were obtained immediately and at 3, 6, 9, 12, 17, and 24 weeks after embolization prior to sacrifice of the animals. All aneurysms were studied macroscopically and histopathologically with the coils in situ. Five of six control aneurysms remained patent. Endovascular occlusion rates between > 90% and 100% were achieved in nine of twelve coiled aneurysms. Follow-up angiography demonstrated recanalization and coil compaction in 5 of them. Gross and microscopic histopathological examination revealed a membrane covering the orifice, intra-aneurysmal scar formation, and development of a neo-intima in both treatment groups at 17 and 24 weeks postembolization. The granulation tissue response appeared to be equally distributed in aneurysms treated with either uncoated or coated coils. Further quantitative morphometric studies are needed to prove if a thrombogenic/antithrombolytic coil-coating might be of value in providing a more enduring anatomic result after GDC-treatment of human brain aneurysms.

Designing therapies that target tumor blood vessels

Traditional cancer treatments seek to attack cancer cells directly, with surgery, radiation, or chemotherapy. But a new wave of therapies is attempting an indirect strike: shutting off the blood vessels through which tumors get the oxygen and nutrients they need to live and grow. Recent work suggests that this might be done with drugs, some naturally occurring, that can prevent tumors from forming the new blood vessels they need. Alternately, as a report appearing on page 547 suggests, it might be possible to shrink or even eliminate tumors by administering agents that trigger clot formation in tumor-feeding vessels.

Tumor infarction in mice by antibody-directed targeting of tissue factor to tumor vasculature

Selective occlusion of tumor vasculature was tested as a therapy for solid tumors in a mouse model. The formation of blood clots (thrombosis) within the tumor vessels was initiated by targeting the cell surface domain of human tissue factor, by means of a bispecific antibody, to an experimentally induced marker on tumor vascular endothelial cells. This truncated form of tissue factor (tTF) had limited ability to initiate thrombosis when free in the circulation, but became an effective and selective thrombogen when targeted to tumor endothelial cells. Intravenous administration of the antibody-tTF complex to mice with large neuroblastomas resulted in complete tumor regressions in 38 percent of the mice.

Comparison between recombinant and rabbit thromboplastin in the management of patients on oral anticoagulant therapy

The aim of this study was to compare recombinant thromboplastin (rTF, ISI = 0.82) with rabbit thromboplastin (RT, ISI = 1.46) in order to evaluate which performed better in our thrombosis centre. To this purpose we randomized 67 patients to be double-blind monitored in two groups for three months either with PT performed with RT or with PT performed with rTF. After this period each patient was shifted to the other group. We considered the following as end points of the study: percentages of PT results within the therapeutic range, number of visits and therapeutic dose adjustments per patient. The "last check in file" method was used to evaluate the laboratory quality of oral anticoagulation for both thromboplastins. The results show that there was no difference in the number of visits per patient between the two groups: 6.9 +/- 1.7 in the rTF group versus 7.3 +/- 1.9 in the RT group (p = 0.19). The variations of therapeutic dose per patient were not different in the two groups: the dose was changed once (range 0-8) in the rTF group and once (range 0-11) in the RT group (p = 0.15). The percentages of PT results within the therapeutic range were not different between the two groups. The "last check in file" method showed similar percentages in both groups: PT results in the therapeutic range were 67.2% in the RT group and 68.8% in the rTF group. We conclude that the two thromboplastins had a similar effect on the end points of the study in spite of the relatively high ISI of the RT.

Comparison of a recombinant thromboplastin with Thrombotest for oral anticoagulant control

Thrombotest results expressed in international normalized ratio (INR) values, obtained in 108 patients on oral anticoagulant treatment, were compared with prothrombin time (PT) results with a recombinant thromboplastin. The former results were obtained on an Amelung coagulometer, the latter on a photo-optical instrument. Using the Thrombotest method, performed within 2 h after sampling as the reference method, a first group of 63 patients had an INR value between 2 and 4. This group was considered as adequately anticoagulated and served as a true positive population in further analysis. The remaining 45 patients (true-negative group) had an INR value below 2 or higher than 4 and could thus be considered as inadequately anticoagulated. Using these definitions, a sensitivity of 86% and a specificity of 96% could be calculated for the PT with the recombinant thromboplastin. All tests from patients on oral anticoagulant treatment were also performed after 24 h storage of the blood or plasma samples at room temperature. When we compared the reference Thrombotest results with those of the late Thrombotest and the late PT recombinant thromboplastin, sensitivities of 86 and 86% as well as specificities of 91 and 96% were found, respectively. In conclusion, PT with a recombinant thromboplastin on a photo-optical instrument, even after prolonged storage of the plasma samples at room temperature, can be considered as suitable for oral anticoagulation control.

Recombinant versus high-sensitivity conventional thromboplastin: a randomized clinical study in patients on oral anticoagulation

A prospective, randomized, double-blind clinical trial was carried out in a single center to compare the clinical and laboratory quality of oral anticoagulant therapy monitored with recombinant tissue factor (RTF) or with a sensitive, human-derived, conventional thromboplastin (CT) in the PT test. Seven hundred and fifty-seven consecutive patients receiving oral anticoagulation for various indications were randomized to RTF (n = 379) or CT (n = 368) for 6 months. Total follow-up was 167 and 153 patient-years for RTF and TP groups respectively. Fifty-six bleeding events were observed: 31 in the RTF group and 25 in the TP group. The incidence of bleeding was 18.5 and 16.5% pt-yrs for RTF and TP patients respectively (n.s.). The event-free follow-up curves were not significantly different between the two groups. The laboratory quality of oral anticoagulation was evaluated with the "last check in file" method: therapeutic INR was found in the same proportion of RTF and TP patients (70.2% vs 68.8%). Our study shows that RTF is as effective as a sensitive, conventional thromboplastin for monitoring oral anticoagulation.

Cerebellar vermis bleeding in a patient with hemophilia A. A case report

A seventeen-year-old man with hemophilia A developed nausea, vomiting, and unsteady gait after mild head trauma. Magnetic resonance imaging clearly demonstrated localized bleeding in cerebellar vermis. Quick administration of factor VIII concentrates prevented further extension of the bleeding and the patient completely recovered without neurologic impairment. In hemophiliac patients, careful evaluation of intracranial lesions is desired after head trauma even if they show only nonspecific symptoms.

Imprecision of prothrombin time monitoring of oral anticoagulation. A survey of hospital laboratories

Prothrombin time monitoring of oral anticoagulation is highly dependent on the tissue thromboplastin used. In the United States, patients have received a higher level of anticoagulation because of the use of a less sensitive thromboplastin. Many advocate the use of an International Normalized Ratio to rectify this problem. Laboratory supervisors from all acute care hospitals in Massachusetts were surveyed to determine the disparity in thromboplastin use and reporting practices for prothrombin time testing. Eighty-eight of 103 (86%) hospitals responded. Fifty-eight lots from six manufacturers of thromboplastin were in use. The International Sensitivity Index of these lots ranged from 1.89 to 2.74. Ninety-nine percent of hospitals reported prothrombin times in raw seconds. Only 5% reported an International Normalized Ratio. Sixteen different coagulation instruments were in use. Close to 70% of laboratory supervisors had little or no understanding of the significance of an International Sensitivity Index or an International Normalized Ratio. The management of oral anticoagulation appears far less precise than had been believed. Prothrombin times in the same individual from different laboratories may have poor correlation. Based on the level of understanding of laboratory supervisors, extensive education will be necessary to change practices and improve accuracy and comparability of prothrombin time testing.

Management of factor VIII inhibitors: evolution and current status

Management of patients with factor VIII (and IX) inhibitors includes management of acute bleeds and methods to induce immune suppression and tolerance and to detect patients at risk of developing inhibitors. The methods used over the years to treat acute bleeding have been more or less successful. The best method is to raise factor VIII levels by human or porcine factor VIII concentrate, but this is not usually possible. Prothrombin complex concentrates, activated or non-activated, have enjoyed some success as factor VIII by passing agents, but the development of recombinant activated factor VII represents a new and promising method of inducing haemoslasis at the site of bleeding whilst minimizing the risk of disseminated intravascular coagulation. Alternatively, the use of tissue factor is under consideration to exploit the extrinsic system. Methods to induce immunological tolerance by use of the 'Bonn' regime or by the introduction of immunomodulation with the 'Malmö' regime of extracorporeal immunodepletion, cyclophosphamide, and intravenous immunoglobulin continue to be attempted with significant but variable success. Gradually the inhibitor problem is being contained, but it is still an important complication of haemophilia therapy.

Recombinant lipoprotein-associated coagulation inhibitor inhibits tissue thromboplastin-induced intravascular coagulation in the rabbit

Lipoprotein-associated coagulation inhibitor produces feed-back inhibition of tissue factor (tissue thromboplastin)-induced coagulation in the presence of factor Xa Recombinant lipoprotein-associated coagulation inhibitor (rLACI) was tested for its ability to modify thromboplastin-induced intravascular coagulation in a rabbit model that allows monitoring of iodine-125 fibrin accumulation/disappearance in the lung and sampling of blood for the measurement of coagulation parameters. Infusion of thromboplastin into the rabbit caused a rapid increase of radioactivity over the lungs, possibly due to the accumulation of 125I fibrin in the lungs, followed by a rapid decline of radioactivity, suggestive of removal of fibrin from the lungs. Thromboplastin also caused a rapid decrease of systemic fibrinogen that was accompanied by a lengthening of the activated partial thromboplastin time and prothrombin time. The effect of coinfusion of rLACI with thromboplastin or bolus injection of rLACI before thromboplastin infusion was studied. At a high dose of rLACI (800 micrograms/kg body weight), the thromboplastin-induced radioactivity increase in the lungs and the systemic fibrinogen decrease were completely suppressed. The activated partial thromboplastin time and prothrombin time of the plasma samples lengthened, possibly due to the presence of thromboplastin in circulation. The thromboplastin-induced radioactivity increase over the lungs was not completely suppressed by lower doses of rLACI (135 to 270 micrograms/kg body weight), but these doses of rLACI prevented systemic fibrinogen decrease. At a bolus dose of 23 micrograms/kg body weight, rLACI provided 50% protection of the fibrinogen consumption (fibrinogen decreased to 82% compared with 65% in rabbits treated with thromboplastin alone). These results show that rLACI is effective in the inhibition of thromboplastin-induced coagulation in vivo.

Treatment of factor VIII inhibitors

Factor VIII inhibitors are antibodies of the IgG class that neutralize the procoagulant activity of FVIII. They arise as alloantibodies in multitransfused haemophilia A patients and spontaneously in some individuals. Therapeutic strategy must be separated into two concepts: treatment of bleeding episodes and treatment of the inhibitor itself. Treatment of an haemorrhagic complication is dependent on the inhibitor titre and the status of the patient as a 'high' or 'low' responder. The choice has to be made between massive amounts of human FVIII concentrate, porcine FVIII and plasma preparations with 'bypassing' activity. Adjuvant therapy such as plasma exchange or extracorporeal passage of plasma over a Protein A sepharose column might be helpful. More recent products are still under evaluation such as FVIIa or recombinant tissue factor. Intravenous immunoglobulins have proven to be helpful mainly in patients with spontaneous inhibitors. Treatment of the inhibitor itself must be started as soon as possible. Several approaches are being used, immunosuppressive therapy or induction of immune tolerance using high intermediate or low doses of FVIII concentrate.

The molecular biology and biochemistry of tissue factor

The cloning of tissue factor (TF) cDNAs has recently been carried out which has allowed the characterization of this cellular receptor for factor VII. The predicted primary structure indicates that it is a multidomain protein comprised of a hydrophilic extracellular domain, a membrane spanning structure and a cytoplasmic region. Post-translational modifications include four potential N-linked glycosylation sites of which three are occupied. There is evidence that the intracellular cysteine residue is thioester-linked to palmitic acid, and that this could enhance the anchoring of the receptor to the membrane. The four remaining cysteine residues are located in the putative extracellular domain and appear to form two intramolecular disulphide bonds. There is no significant homology between TF and any other published protein sequence in current databases. There is evidence that TF is the primary initiator of the coagulation cascade. Early models of coagulation tended to assign TF to a subordinate role, but now it is widely accepted that the extrinsic pathway is critical as TF/FVIIa activates both FX and FIX. It has been reported that zymogen FVII has catalytic activity and this would indicate that the simple complexing of FVII and TF is sufficient to initiate coagulation without an infinite regression of proteolytic events. Many cell types synthesize TF constitutively but, significantly, endothelial cells do not normally express TF on their surfaces, consistent with a quiescent haemostatic system. Recently a number of agonists known to be thrombogenic in vivo have been shown to induce de novo synthesis of TF by endothelial cells. TF thus operates at two levels: exposure of the subendothelium to blood results in the binding of FVII to TF and consequently to clot formation, and induction of TF synthesis by a variety of agonists results in the intact endothelium becoming procoagulant. In concert with TF expressed by monocytes and macrophages this endothelial cell procoagulant activity may play a role in the pathogenesis of thrombotic disease.

Factor VIII-bypassing activity of bovine tissue factor using the canine hemophilic model

The bleeding disorder of hemophilia A currently treated by replacement therapy of the missing coagulation factor, factor VIII, is frequently complicated by the development of neutralizing antibodies. The therapeutic potential of attenuated forms of the lipid-associated glycoprotein tissue factor, a known initiator of coagulation, was investigated as a factor VIII-by-passing activity. The protein moiety of tissue factor (Apo-TF) was partially purified and exhibited minimal procoagulant activity before relipidation in vitro. In pilot studies, Apo-TF injection into rabbits previously anticoagulated with an antibody to factor VIII was found to have a procoagulant effect. The efficacy of the material was further demonstrated when injection of Apo-TF in hemophilic dogs resulted in a normalization of the cuticle bleeding time. Little or no change in the blood parameters associated with disseminated intravascular coagulation was observed at lower doses, although mild to moderate effects were seen at higher doses. These data suggest a novel role for Apo-TF preparations as a potential therapeutic agent for hemophiliacs with antibodies to factor VIII once the potential thrombogenicity of such materials is evaluated.

The Australasian Reference Thromboplastin: I. A study in bleeding patients

The prothrombin time, activated partial thromboplastin time, thrombin time, and skin bleeding time, with assays of factors II, VII, IX, and X, platelet count, and liver function tests were performed on a group of patients receiving long term warfarin therapy. There were 17 bleeding patients and 13 non-bleeding patients. A study was made, using the Australasian Reference Thromboplastin and 2 other thromboplastic reagents in common use. The Australasian Reference Thromboplastin was shown to be more sensitive to the coumarin induced coagulation defect than rabbit brain thromboplastin, and hence of more value in preventing haemorrhagic complications. The level of factor II assayed by the one stage method was a useful independent indicator of the intensity of oral anticoagulation, and correlated well with the development of bleeding.

Comparison of avitene, topical thrombin, and gelfoam as sole hemostatic agent in tuboplasties

Forty-eight virgin guinea pigs were subjected to bilateral sectioning of the uterine horn and cuff type salpingostomy. Avitene, Topical Thrombin, or Gelfoam was used as the sole hemostatic agent in each of three study groups. Bipolar cauterization was used in a control series. These agents were compared with regard to ease of application, degree of adhesion formation, net surface area, and microscopic evaluation of degree of fibrosis and inflammatory reaction. The results revealed no statistically significant differences among the various methods of hemostasis. Data were evaluated by uni- and multivariate analyses. Several trends in the data were noted: the greatest amount of fibrosis was associated with Topical Thrombin and Avitene, and the greatest inflammatory response was associated with Avitene. These agents show no superiority to currently used cautery methods of obtaining hemostasis.