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Schut A, Hyseni A, Adelmeijer J, Meijers JCM, de Groot PG, Lisman T. Sustained pro-haemostatic activity of rFVIIa in plasma and platelets in non-bleeding pigs may explain the efficacy of a once-daily prophylaxis in humans. Thromb Haemost 2017; 112:304-10. [DOI: 10.1160/th13-09-0798] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 03/08/2014] [Indexed: 11/05/2022]
Abstract
SummaryRecombinant factor VIIa (rFVIIa) is registered for treatment of inhibitor-complicated haemophilia, and a once-daily prophylactic administration of rFVIIa is successful in reducing the number of bleeding events. This suggests that a single rFVIIa dose has a pro-haemostatic effect up to 24 hours (h), which is difficult to explain given its half-life of 2 h. In this study, six pigs received a 90 µg/kg rFVIIa bolus. Plasma was collected and platelets were isolated at various time points up to 48 h, and analysed for FVIIa levels and associated haemostatic activity. Elevated plasma FVIIa levels were detected up to 24 h post-administration (36 (32–56) mU/ml [median (interquartile range [IQR]), 24 h] vs 2 (2–14) mU/ml [baseline]). Corresponding prothrombin time (PT) values remained shortened compared to baseline until 24 h post-administration (9.4 (9.3–9.9) seconds (s) [24 h] vs 10.5 (10.2–11.0) s [baseline], p ≤0.01). The lag time in thrombin generation testing as well as clotting times in plasma-based assays were shortened up to 12 or 24 h post-administration, respectively (lag times 1.8 (1.7–2.1) minutes (min) [12 h] vs 2.3 (2.3–2.6) min [baseline], p ≤0.01 and clotting times 3.8 (3.2–3.9) min [24 h] vs 5.2 (4.6–5.5) min [baseline], p ≤0.001). Platelet FVIIa levels were elevated up to 48 h (7.7 (3.4–9.0) ng VIIa/mg actin [48 h] vs 2.5 (0.7–4.8) ng VIIa/mg actin [baseline]). In conclusion, elevated and haemostatically active plasma and platelet FVIIa levels are detectable up to 24–48 h following rFVIIa administration in pigs. This prolonged pro-haemostatic effect of FVIIa may explain the prophylactic efficacy of a once-daily rFVIIa treatment.
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Nielsen CH, Erlandsson M, Jeppesen TE, Jensen MM, Kristensen LK, Madsen J, Petersen LC, Kjaer A. Quantitative PET Imaging of Tissue Factor Expression Using 18F-Labeled Active Site-Inhibited Factor VII. J Nucl Med 2015; 57:89-95. [PMID: 26383146 DOI: 10.2967/jnumed.115.154849] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 08/19/2015] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Tissue factor (TF) is upregulated in many solid tumors, and its expression is linked to tumor angiogenesis, invasion, metastasis, and prognosis. A noninvasive assessment of tumor TF expression status is therefore of obvious clinical relevance. Factor VII is the natural ligand to TF. Here we report the development of a new PET tracer for specific imaging of TF using an (18)F-labeled derivative of factor VII. METHODS Active site-inhibited factor VIIa (FVIIai) was obtained by inactivation with phenylalanine-phenylalanine-arginine-chloromethyl ketone. FVIIai was radiolabeled with N-succinimidyl 4-(18)F-fluorobenzoate and purified. The corresponding product, (18)F-FVIIai, was injected into nude mice with subcutaneous human pancreatic xenograft tumors (BxPC-3) and investigated using small-animal PET/CT imaging 1, 2, and 4 h after injection. Ex vivo biodistribution was performed after the last imaging session, and tumor tissue was preserved for molecular analysis. A blocking experiment was performed in a second set of mice. The expression pattern of TF in the tumors was visualized by immunohistochemistry and the amount of TF in tumor homogenates was measured by enzyme-linked immunosorbent assay and correlated with the uptake of (18)F-FVIIai in the tumors measured in vivo by PET imaging. RESULTS The PET images showed high uptake of (18)F-FVIIai in the tumor regions, with a mean uptake of 2.5 ± 0.3 percentage injected dose per gram (%ID/g) (mean ± SEM) 4 h after injection of 7.3-9.3 MBq of (18)F-FVIIai and with an average maximum uptake in the tumors of 7.1 ± 0.7 %ID/g at 4 h. In comparison, the muscle uptake was 0.2 ± 0.01 %ID/g at 4 h. At 4 h, the tumors had the highest uptake of any organ. Blocking with FVIIai significantly reduced the uptake of (18)F-FVIIai from 2.9 ± 0.1 to 1.4 ± 0.1 %ID/g (P < 0.001). The uptake of (18)F-FVIIai measured in vivo by PET imaging correlated (r = 0.72, P < 0.02) with TF protein level measured ex vivo. CONCLUSION (18)F-FVIIai is a promising PET tracer for specific and noninvasive imaging of tumor TF expression. The tracer merits further development and clinical translation, with potential to become a companion diagnostics for emerging TF-targeted therapies.
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Affiliation(s)
- Carsten H Nielsen
- Minerva Imaging, Copenhagen, Denmark Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark; and
| | - Maria Erlandsson
- Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark; and
| | - Troels E Jeppesen
- Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark; and
| | - Mette M Jensen
- Minerva Imaging, Copenhagen, Denmark Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark; and
| | - Lotte K Kristensen
- Minerva Imaging, Copenhagen, Denmark Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark; and
| | - Jacob Madsen
- Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark; and
| | | | - Andreas Kjaer
- Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark; and
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Recombinant fusion protein linking factor VIIa with albumin (rVIIaFP): Tissue distribution in rats. Thromb Res 2014; 134:495-502. [DOI: 10.1016/j.thromres.2014.05.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 04/17/2014] [Accepted: 05/22/2014] [Indexed: 11/21/2022]
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Agersø H, Tranholm M. Pharmacokinetics and pharmacodynamics of rFVIIa and new improved bypassing agents for the treatment of haemophilia. Haemophilia 2012; 18 Suppl 5:6-10. [PMID: 22757678 DOI: 10.1111/j.1365-2516.2012.02886.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Animal models have played a critical role in developing our understanding of haemophilia and its treatment. For example, studies in mice and dogs have provided insights into the pharmacokinetics and pharmacodynamics of recombinant activated factor VII (rFVIIa). Such studies have shown that antithrombin has a significant impact on clearance of rFVIIa, which explains discrepancies between the antigen and activity half-lives of rFVIIa. Animal studies have also shown that the major clearance organs for rFVIIa are the liver and the kidneys, whereas distribution studies suggest that FVII and rFVIIa leave the circulation and enter the tissues, before returning to the circulation through the lymph. One agent that has benefited greatly from the use of animal models in its development is vatreptacog alfa, a new analogue of rFVIIa. Promising in vitro results, including increased generation of FXa, shortened clotting times and increased clot stability, were subsequently confirmed in animal models. In a severe tail-bleed model in FVIII knock-out mice, reduction in maximal blood loss was substantially greater with vatreptacog alfa than with rFVIIa, FVIII or plasma-derived activated prothrombin complex concentrate. In a mouse model of joint bleeding, rFVIIa and vatreptacog alfa significantly reduced bleeding compared with vehicle-treated haemophilic controls. More recently, a model of endothelial injury based on mouse cremaster muscle has been developed. Overall, animal models are a valuable tool in elucidating the haemostatic process and the effects of therapeutic agents, although direct extrapolation to the clinical setting should be done with caution.
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Affiliation(s)
- Henrik Agersø
- Biopharmaceuticals Research Unit, Novo Nordisk A/S, Måløv, Denmark
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MONAHAN PAULE, DORIA ANDREAS, LJUNG ROLF, JIMÉNEZ-YUSTE VICTOR. Optimizing joint function: new knowledge and novel tools and treatments. Haemophilia 2012; 18 Suppl 5:17-26. [DOI: 10.1111/j.1365-2516.2012.02888.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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6
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Pharmacokinetics, distribution, and excretion of 125I-labeled human plasma-derived-FVIIa and -FX with MC710 (FVIIa/FX mixture) in rats. Thromb Res 2012; 129:62-7. [DOI: 10.1016/j.thromres.2011.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Revised: 03/16/2011] [Accepted: 04/26/2011] [Indexed: 11/19/2022]
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7
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In vivo clearance and metabolism of recombinant activated factor VII (rFVIIa) and its complexes with plasma protease inhibitors in the liver. Thromb Res 2011; 127:356-62. [DOI: 10.1016/j.thromres.2010.12.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 12/15/2010] [Accepted: 12/22/2010] [Indexed: 11/18/2022]
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8
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Agersø H, Brophy DF, Pelzer H, Martin EJ, Carr M, Hedner U, Ezban M. Recombinant human factor VIIa (rFVIIa) cleared principally by antithrombin following intravenous administration in hemophilia patients. J Thromb Haemost 2011; 9:333-8. [PMID: 21114621 PMCID: PMC3030656 DOI: 10.1111/j.1538-7836.2010.04152.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE The objective of the present study was to evaluate the pharmacokinetics and the clearance pathways of rFVIIa after intravenous administration to hemophilia patients. METHODS Ten severe hemophilia patients were included in the study; all patients were intravenously administered a clinically relevant dose of 90 μg kg(-1) (1.8 nmol kg(-1)) rFVIIa. Blood samples were collected consecutively to describe the pharmacokinetics of rFVIIa. All samples were analyzed using three different assays: a clot assay to measure the activity (FVIIa:C), an enzyme immunoassay (EIA) to measure the antigen levels (FVII:Ag), and an EIA (FVIIa-AT) to measure the FVIIa antithrombin III (AT) complex. Pharmacokinetic parameters were evaluated both by use of standard non-compartmental methods and by use of mixed effects methods. A population pharmacokinetic model was used to simultaneously model all three datasets. The total body clearance of rFVIIa:C was estimated to be 38 mL h(-1) kg(-1). The rFVII-AT complex formation was responsible for 65% of the total rFVIIa:C clearance. The initial and the terminal half-life of rFVIIa:C was estimated to be 0.6 and 2.6 h, respectively. The formation of rFVII-AT complex was able to explain the difference observed between the rFVIIa:C and the rFVII:Ag concentration. The non-compartmental analysis resulted in almost identical parameters.
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Affiliation(s)
- Henrik Agersø
- Pharmacology, Biopharmaceuticals Research Unit, Novo Nordisk A/S
| | - Donald F. Brophy
- Coagulation Advancement Laboratory, Virginia Commonwealth University School of Pharmacy, Richmond, VA, USA
| | - Hermann Pelzer
- Pharmacology, Biopharmaceuticals Research Unit, Novo Nordisk A/S
| | - Erika J. Martin
- Coagulation Advancement Laboratory, Virginia Commonwealth University School of Pharmacy, Richmond, VA, USA
| | | | | | - Mirella Ezban
- Pharmacology, Biopharmaceuticals Research Unit, Novo Nordisk A/S
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9
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Monahan PE, Sun J. Hemophilic synovitis: factor VII and the potential role of extravascular factor VIIa. Thromb Res 2010; 125 Suppl 1:S63-6. [PMID: 20227556 DOI: 10.1016/j.thromres.2010.02.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The initiation of coagulation via tissue factor/factor VIIa is relatively weak in normal synovium and joint tissues, so that hemophilic patients with additional deficiency of the intrinsic pathway of coagulation are especially at risk for joint bleeding and the development of hemophilic synovitis. The inflamed joint that results from recurrent bleeding-induced injury, however, may be an environment in which pharmacologic doses of factor VIIa have potentially greater procoagulant action than in the uninjured joint. There is accumulating evidence suggesting that coagulation factors in the extravascular space, and not only circulating plasma factors, have the potential to contribute to hemostatic protection of joints. The potential role of extravascular factor VIIa is considered.
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Affiliation(s)
- Paul E Monahan
- Pediatric Hematology/Oncology, University of North Carolina at Chapel Hill, NC 27599, USA.
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10
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Gopalakrishnan R, Hedner U, Ghosh S, Nayak RC, Allen TC, Pendurthi UR, Rao LVM. Bio-distribution of pharmacologically administered recombinant factor VIIa (rFVIIa). J Thromb Haemost 2010; 8:301-10. [PMID: 19943873 PMCID: PMC2849270 DOI: 10.1111/j.1538-7836.2009.03696.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Recent clinical studies suggest that the prophylactic use of recombinant factor VIIa (rFVIIa) markedly reduces the number of bleeding episodes in hemophilic patients with inhibitors. Given the short biological half-life of rFVIIa, it is unclear how rFVIIa could be effective in prophylactic treatment. OBJECTIVES To examine the extravascular distribution of pharmacologically administered rFVIIa to obtain clues on how rFVIIa could work in prophylaxis. METHODS Recombinant mouse FVIIa tagged with AF488 fluorophore (AF488-FVIIa) was administered into mice via the tail vein. At different time intervals following the administration, mice were exsanguinated and various tissues were collected. The tissue sections were processed for immunohistochemistry to evaluate distribution of rFVIIa. RESULTS rFVIIa, immediately following the administration, associated with the endothelium lining of large blood vessels. Within 1 h, rFVIIa bound to endothelial cells was transferred to the perivascular tissue surrounding the blood vessels and thereafter diffused throughout the tissue. In the liver, rFVIIa was localized to sinusoidal capillaries and accumulated in hepatocytes. In bone, rFVIIa was accumulated in the zone of calcified cartilage and some of it was retained there for a week. The common finding of the present study is that rFVIIa in extravascular spaces was mostly localized to regions that contain TF expressing cells. CONCLUSIONS The present study demonstrates that pharmacologically administered rFVIIa readily associates with the vascular endothelium and subsequently enters into extravascular spaces where it is likely to bind to TF and is retained for extended time periods. This may explain the prolonged pharmacological effect of rFVIIa.
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Affiliation(s)
- R Gopalakrishnan
- Center for Biomedical Research, The University of Texas Health Science Center, Tyler, TX 75703, USA
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11
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OBERGFELL A, AUVINEN MK, MATHEW P. Recombinant activated factor VII for haemophilia patients with inhibitors undergoing orthopaedic surgery: a review of the literature. Haemophilia 2008; 14:233-41. [DOI: 10.1111/j.1365-2516.2007.01617.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Abstract
The liver is believed to be the primary clearance organ for coagulation proteases, including factor VIIa (FVIIa). However, at present, clearance mechanisms for FVIIa in liver are unknown. To obtain information on the FVIIa clearance mechanism, we investigated the binding and internalization of FVIIa in liver cells using a human hepatoma cell line (HEPG2), and primary rat and human hepatocytes as cell models. 125I-FVIIa bound to HEPG2 cells in a time- and dose-dependent manner. Anti-tissue factor antibodies reduced the binding by about 25%, whereas 50-fold molar excess of unlabeled FVIIa had no effect. HEPG2 cells internalized FVIIa with a rate of 10 fmol 10(-5) cells h(-1). In contrast to HEPG2 cells, FVIIa binding to primary rat hepatocytes was completely independent of TF, and excess unlabeled FVIIa partly reduced the binding of 125I-FVIIa to rat hepatocytes. Further, compared with HEPG2 cells, three- to fourfold more FVIIa bound to rat primary hepatocytes, and the bound FVIIa was internalized at a faster rate. Similar FVIIa binding and internalization profiles were observed in primary human hepatocytes. Plasma inhibitors had no effect on FVIIa binding and internalization in hepatocytes. In contrast, annexin V, which binds to phosphatidylserine, blocked the binding and internalization. Consistent with this, binding of gla-domain-deleted FVIIa to hepatocytes was markedly diminished. In summary, the data presented herein reveal differences between HEPG2 cells and primary liver cells in FVIIa binding and internalization, and suggest that the rapid turnover of membrane and not a receptor-mediated endocytosis may be responsible for internalization of FVII/FVIIa in primary hepatocytes.
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Affiliation(s)
- Gertrud Hjortoe
- Health Care Discovery, Novo Nordisk, Maalov, Denmark; and
- Biomedical Research, The University of Texas Health Center at Tyler, Tyler, TX, USA
| | | | | | - L. Vijaya Mohan Rao
- Biomedical Research, The University of Texas Health Center at Tyler, Tyler, TX, USA
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Kristensen AT, Edwards ML, Devey J. Potential uses of recombinant human factor VIIa in veterinary medicine. Vet Clin North Am Small Anim Pract 2003; 33:1437-51. [PMID: 14664207 DOI: 10.1016/j.cvsm.2003.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
In human beings, rFVIIa has been used successfully to promote hemostasis in patients with various bleeding disorders. Patients with hemophilia, thrombocytopenia, and thrombocytopathy have been effectively and safely treated as well as patients with severe trauma or surgery resulting in profuse bleeding and patients with impaired liver function. Given these successes, the possibility of using rFVIIa in veterinary medicine is appealing. The clinical indications and uses in veterinary medicine would be similar, but there are currently two major obstacles: immunogenicity and cost. If these problems can be addressed, rFVIIa may become a valuable and indispensable therapy, especially in the emergency and critical care settings. The use of rFVIIa could allow for successful treatment of otherwise intractable bleeding as well as decrease the number of blood transfusions needed.
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Affiliation(s)
- Annemarie T Kristensen
- Department of Clinical Studies, Royal Veterinary and Agricultural University, Copenhagen, 16 Dyrlaegevej, DK-1870 Frederiksberg C, Denmark.
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Chan JC, Cornelissen I, Collen D, Ploplis VA, Castellino FJ. Combined factor VII/protein C deficiency results in intrauterine coagulopathy in mice. J Clin Invest 2000; 105:897-903. [PMID: 10749569 PMCID: PMC377488 DOI: 10.1172/jci9095] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
To determine whether an additional loss of the coagulation factor VII (FVII) gene influenced the coagulopathy observed in protein C gene-deficient (PC(-/-)) embryos and neonates, we crossed mice doubly heterozygous for the factor VII (FVII(+/-)) and protein C (PC(+/-)) genes to produce offspring possessing the 9 predicted genotypic combinations. FVII(-/-)/PC(-/-) embryos, although present at their expected Mendelian frequency, displayed a phenotype that had not been observed in either the FVII or PC singly deficient embryos. At E12.5 days postcoitum (dpc), FVII(-/-)/PC(-/-) embryos demonstrated an intra- and extravascular coagulopathy that progressed with substantial concomitant hemorrhage and peripheral edema by E17.5dpc, resulting in mortality immediately after birth. FVII(+/-)/PC(-/-) embryos showed a less severe phenotype, suggesting a gene dosage effect. The lack of rescue of PC(-/-) embryos and neonates and augmented coagulopathy resulting from an additional heterozygous or homozygous FVII deficiency are probably due to increased factor Xa and thrombin generation, resulting from loss of FVIIa-dependent tissue factor pathway inhibitor function and the absence of control at the levels of factors Va and VIIIa. The presence of fibrin in embryos in the absence of fetal FVII suggests that significant clot-generating potential exists outside of the embryonic factor VII-dependent pathway.
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Affiliation(s)
- J C Chan
- W.M. Keck Center for Transgene Research and the Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
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Abstract
Haemostasis is initiated by the complex formed by TF and FVIIa present in the blood (1% of the FVII protein). Recombinant FVIIa, which is active only after having formed complex with TF exposed following tissue damage, has been demonstrated to induce haemostasis in haemophilia patients with life- and limb-threatening bleedings with an efficacy rate of 76-84% in patients having failed on other treatment. Several had proven septicaemia but only one patient developed consumption coagulaopathy during extensive surgical manipulation and removal of myonecrotic tissue. No antibody formation against FVII has been seen in haemophilia patients. In 13 major surgical episodes complete intra- and post-operative haemostasis was achieved. rFVIIa has been used successfully in FVII-deficient patients and has been found to normalise the PT in patients with liver disease and in warfarin treated individuals. Single patients with platelet defects and with vWillebrand's disease type 3 achieved haemostasis with rFVIIa.
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Affiliation(s)
- U Hedner
- Novo Nordisk A/S, Vessel Wall Biology, Gentofte, Denmark
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16
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Rosen ED, Chan JC, Idusogie E, Clotman F, Vlasuk G, Luther T, Jalbert LR, Albrecht S, Zhong L, Lissens A, Schoonjans L, Moons L, Collen D, Castellino FJ, Carmeliet P. Mice lacking factor VII develop normally but suffer fatal perinatal bleeding. Nature 1997; 390:290-4. [PMID: 9384381 DOI: 10.1038/36862] [Citation(s) in RCA: 151] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Blood coagulation in vivo is initiated by factor VII (FVII) binding to its cellular receptor tissue factor (TF). FVII is the only known ligand for TF, so it was expected that FVII-deficient embryos would have a similar phenotype to TF-deficient embryos, which have defective vitello-embryonic circulation and die around 9.5 days of gestation. Surprisingly, we find that FVII-deficient (FVII-/-) embryos developed normally. FVII-/- mice succumbed perinatally because of fatal haemorrhaging from normal blood vessels. At embryonic day 9.5, maternal-fetal transfer of FVII was undetectable and survival of embryos did not depend on TF-FVII-initiated fibrin formation. Thus, the TF-/- embryonic lethal and the FVII-/- survival-phenotypes suggest a role for TF during embryogenesis beyond fibrin formation.
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Affiliation(s)
- E D Rosen
- Center for Transgene Technology and Gene Therapy, Flanders Interuniversity Institute for Biotechnology, Leuven, Belgium
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Thomsen MK, Hansen BS, Nilsson P, Nowak J, Johansen PB, Thomsen PD, Christiansen J. Pharmacological characterization of a biosynthetic trisulfide-containing hydrophobic derivative of human growth hormone: comparison with standard 22 K growth hormone. PHARMACOLOGY & TOXICOLOGY 1994; 74:351-8. [PMID: 7937569 DOI: 10.1111/j.1600-0773.1994.tb01372.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Growth hormone is the classical anabolic hormone which promotes organ growth after binding to somatogenic target cell receptors, present in various target tissues. The present study elucidated the pharmacological characteristics in vitro and in vivo of human growth hormone and a recently identified by-product of a recombinant human growth hormone preparation; i.e. a trisulfide-containing (cys 182-cys 189) hydrophobic, folding derivative of growth hormone, hydrophobic derivative-growth hormone. Standard growth hormone and hydrophobic derivative-growth hormone possessed similar characteristics in vitro, both as regards binding to the somatogenic receptor on the human IM-9 cell line, and the prolactin receptor-mediated proliferation of rat Nb2 cells. This indicates that no change occurs in the binding characteristics in spite of a change in conformation of the molecule. Using an ELISA assay that detected standard and hydrophobic derivative-growth hormone equally well, the plasma pharmacokinetical profiles of the preparations following a single intravenous or subcutaneous dose were indistinguishable. Thus, following initial disposition of hydrophobic derivative-growth hormone and standard growth hormone into a volume, V1, of one to two times the plasma volume, almost 90% of either compound disappeared from plasma during the alpha-phase of the plasma decay curve. Similar half-lives of 4-5 min. were found for hydrophobic derivative-growth hormone and standard growth hormone during this phase, indicating rapid removal of drug from the circulation. Also, the AUC and Cmax values for standard and hydrophobic derivative-growth hormone did not differ following intravenous or subcutaneous administration.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M K Thomsen
- Novo Nordisk, Research and Development, Bagsvaerd, Denmark
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Krogsgaard Thomsen M, Friis C, Sehested Hansen B, Johansen P, Eschen C, Nowak J, Poulsen K. Studies on the renal kinetics of growth hormone (GH) and on the GH receptor and related effects in animals. J Pediatr Endocrinol Metab 1994; 7:93-105. [PMID: 8061766 DOI: 10.1515/jpem.1994.7.2.93] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Growth hormone (GH) is filtered through the kidney, and may exert effects on renal function when presented via the circulation. Investigations on kidney-related aspects of GH are increasing in number. Using in vitro and in vivo approaches, the present study attempted to provide answers to a number of unresolved or debated issues. In vitro, we detected both GH and type 1 IGF receptors (R) in a porcine renal epithelial cell line. The saturation and down regulation kinetics of the GH-R indicate that it has the properties of a classical GH-R. Furthermore, the simultaneous presence of GH-R and IGF-R on a phenotypically homogeneous cell line suggests the presence of GH-induced auto-/paracrine IGF-1 bioactivity in the kidney. Experiments with isolated proximal rabbit tubules incubated with physiological concentrations of 125I-GH demonstrated a time-and dose-dependent increase in unlabelled GH-displaceable cell-associated radioactivity, lending support to the concept of GH mediating its renal effects via proximal tubular GH-R. Short term administration of GH to rats and humans elicited electrolyte and water retention that may cause edema in adults. In the present study, long term administration of GH to rats caused only a minor increase in serum phosphate levels, with no changes observed in the renal electrolyte clearance. During the first 4 days of GH treatment in rats, no change in plasma renin activity was detected and we were thus unable to confirm the hypothesis that the renin-angiotensin system is responsible for the early phase of GH-associated fluid retention. Pharmacokinetically, when GH was administered to rats with functional disconnection of the kidneys as a model of renal insufficiency, the whole body clearance of GH decreased by ca. two thirds, and was reflected by an increase in the mean residence time and AUCplasma for GH. The plasma half-life, however, was not significantly affected, suggesting that the volume of distribution (Vd) had decreased for the GH administered to the renally compromised animals. A renal contribution to the Vd was visualized as intense radioactive staining in the kidney region on whole body autoradiographs (WBA) of rats dosed with 125I-labelled hGH. The liver region was also intensely stained. Kidney-associated radioactivity was found to be related not only to glomerular filtration, but also to peritubular uptake, since the renal clearance of free GH was found to exceed the GFR.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- M Krogsgaard Thomsen
- Biopharmaceuticals Division, Research and Development, Novo Nordisk A/S, Gentofte, Denmark
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Thomsen MK, Wildgoose P, Nilsson P, Hedner U. Accumulation of the recombinant factor VIIa in rat bone: importance of the Gla-domain and relevance to factor IX, another vitamin K-dependent clotting factor. PHARMACOLOGY & TOXICOLOGY 1993; 73:127-32. [PMID: 7903449 DOI: 10.1111/j.1600-0773.1993.tb01549.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The vitamin K-dependent clotting factors II, VII, IX, and X are proteins which undergo gamma-carboxylation of specific glutamic acid residues prior to secretion from the liver. These unique Ca2+ binding amino acids allow the interaction of the proteins with cell surface phospholipids, a function that is crucial for expression of full procoagulant activity of the proteins. The N-terminal region of the molecule contains the gamma-carboxylation sites and is termed the Gla-domain. A preliminary observation in rats suggested that mineralized bone accumulated activated recombinant FVII (rFVIIa: NovoSeven) as well as the non-activated, single chain rFVII. The present study investigated the role of the Gla-domain in the accumulation of rFVII in bone, as well as the influence of the activation state of FVII on this phenomenon. Rats were treated with 125I-labelled rFVII, rFVIIa, Gla-domainless rFVIIa, factor IX, iodide, or recombinant human growth hormone (rhGH). Following sacrifice, radioactivity was measured in mineralized bone, among other tissues. Following administration of 125I-radiolabelled rFVII, rFVIIa and factor IX, but not Gla-domainless rFVIIa, iodide or rhGH, extensive sequestration occurred in endochondrally as well as intramenbranously ossified bones. The results indicate that the proteins containing a Gla-domain, and only these, are sequestered in bone. Additionally, the normally occurring form of FVII in the circulation, the single-chain FVII, exhibited similar kinetics in rat bone and plasma, as the two-chain rFVIIa. The half-life of rFVII/rFVIIa in mineralized bone was between 3 and 4 days, implying that significant bone accumulation of the factor will take place at steady state.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M K Thomsen
- Biopharmaceuticals Division, Novo Nordisk A/S, Gentofte, Denmark
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