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American Journal of Physiology. Renal... Aug 2014Fibrinogen (Fg) has been implicated in the pathogenesis of several fibrotic disorders by acting as a profibrotic ligand for a variety of cellular surface receptors and...
Fibrinogen (Fg) has been implicated in the pathogenesis of several fibrotic disorders by acting as a profibrotic ligand for a variety of cellular surface receptors and by modulating the provisional fibrin matrix formed after injury. We demonstrated increased renal Fg expression after unilateral ureteral obstruction and folic acid (FA) nephropathy in mice, respectively. Urinary Fg excretion was also increased in FA nephropathy. Using in vitro and in vivo approaches, our results suggested that IL-6 mediates STAT3 activation in kidney fibrosis and that phosphorylated (p)STAT3 binds to Fgα, Fgβ, and Fgγ promoters in the kidney to regulate their transcription. Genetically modified Fg heterozygous mice (∼75% of normal plasma Fg levels) exhibited only 3% kidney interstitial fibrosis and tubular atrophy after FA nephropathy compared with 24% for wild-type mice. Fibrinogenolysis through Ancrod administration after FA reduced interstitial fibrosis more than threefold compared with vehicle-treated control mice. Mechanistically, we show that Fg acts synergistically with transforming growth factor (TGF)-β1 to induce fibroblast proliferation and activates TGF-β1/pSMAD2 signaling. This study offers increased understanding of Fg expression and molecular interactions with TGF-β1 in the progression to kidney fibrosis and, importantly, indicates that fibrinogenolytics like Ancrod present a treatment opportunity for a yet intractable disease.
Topics: Ancrod; Animals; Disease Progression; Fibrinogen; Fibrosis; Hep G2 Cells; Humans; Interleukin-6; Kidney; Kidney Diseases; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; STAT3 Transcription Factor; Smad2 Protein; Transforming Growth Factor beta1; Ureteral Obstruction
PubMed: 25007874
DOI: 10.1152/ajprenal.00189.2014 -
Stroke May 2009Epidemiological studies have found strong correlations between elevated plasma fibrinogen levels and both ischemic stroke incidence and stroke mortality. Little is known...
BACKGROUND AND PURPOSE
Epidemiological studies have found strong correlations between elevated plasma fibrinogen levels and both ischemic stroke incidence and stroke mortality. Little is known about the influence of fibrinogen levels on functional stroke outcome.
METHODS
Placebo data from the Stroke Treatment with Ancrod Trial (STAT) and European Stroke Treatment with Ancrod Trial (ESTAT) were analyzed. Fibrinogen levels were determined within 3 hours (STAT) or 6 hours (ESTAT) of stroke onset and at preset intervals throughout 5 days of intravenous infusions. Barthel Index scores at 90 days quantified functional outcomes. The association between initial fibrinogen levels and functional outcomes was evaluated using a multiple logistic regression analysis.
RESULTS
Fibrinogen levels increased gradually over the first 24 hours from a pretreatment median value of 340 mg/dL to a 24-hour median value of 376 mg/dL. In a univariate analysis, the proportion of patients with good functional outcome decreased with increasing quartiles of initial fibrinogen levels in both STAT (36.0% to 26.2%) and ESTAT (53.8% to 24.8%). In a multifactorial analysis, the same trend was observed. Patients with initial fibrinogen levels <450 mg/dL had better outcomes in both studies; the difference (42.0% versus 21.6%) was significant in ESTAT (P=0.0006), even when corrected for age and initial stroke severity.
CONCLUSIONS
The independent association of higher initial fibrinogen levels with poor outcome needs to be verified using a larger acute stroke dataset. Even in the present small populations, the apparent association of these 2 variables suggests that treatments designed to reduce fibrinogen levels could potentially be important in treating acute ischemic stroke.
Topics: Acute Disease; Aged; Cerebral Hemorrhage; Disability Evaluation; Factor Analysis, Statistical; Female; Fibrinogen; Humans; Male; Middle Aged; Stroke; Survival; Treatment Outcome
PubMed: 19299642
DOI: 10.1161/STROKEAHA.108.527804 -
Toxins Apr 2023In Southeast Asia, the Malayan Pit Viper () is a venomous snake species of medical importance and bioprospecting potential. To unveil the diversity of its toxin genes,...
Venom Gland Transcriptome Assembly and Characterization for (Kuhl, 1824), the Malayan Pit Viper from Malaysia: Unravelling Toxin Gene Diversity in a Medically Important Basal Crotaline.
In Southeast Asia, the Malayan Pit Viper () is a venomous snake species of medical importance and bioprospecting potential. To unveil the diversity of its toxin genes, this study assembled and analyzed the venom gland transcriptome of from Malaysia. The expression of toxin genes dominates the gland transcriptome by 53.78% of total transcript abundance (based on overall FPKM, Fragments Per Kilobase Million), in which 92 non-redundant transcripts belonging to 16 toxin families were identified. Snake venom metalloproteinase (SVMP, PI > PII > PIII) is the most dominant family (37.84% of all toxin FPKM), followed by phospholipase A (29.02%), bradykinin/angiotensin-converting enzyme inhibitor-C-type natriuretic peptide (16.30%), C-type lectin (CTL, 10.01%), snake venom serine protease (SVSP, 2.81%), L-amino acid oxidase (2.25%), and others (1.78%). The expressions of SVMP, CTL, and SVSP correlate with hemorrhagic, anti-platelet, and coagulopathic effects in envenoming. The SVMP metalloproteinase domains encode hemorrhagins (kistomin and rhodostoxin), while disintegrin (rhodostomin from P-II) acts by inhibiting platelet aggregation. CTL gene homologues uncovered include rhodocytin (platelet aggregators) and rhodocetin (platelet inhibitors), which contribute to thrombocytopenia and platelet dysfunction. The major SVSP is a thrombin-like enzyme (an ancrod homolog) responsible for defibrination in consumptive coagulopathy. The findings provide insight into the venom complexity of and the pathophysiology of envenoming.
Topics: Animals; Malaysia; Transcriptome; Snake Venoms; Agkistrodon; Metalloproteases; Viper Venoms
PubMed: 37235350
DOI: 10.3390/toxins15050315 -
Toxicological Sciences : An Official... Jan 2011Alpha-naphthylisothiocyanate (ANIT)-induced cholestatic liver injury causes tissue factor (TF)-dependent coagulation in mice, and TF deficiency reduces ANIT-induced...
Alpha-naphthylisothiocyanate (ANIT)-induced cholestatic liver injury causes tissue factor (TF)-dependent coagulation in mice, and TF deficiency reduces ANIT-induced liver injury. However, the mechanism whereby TF contributes to hepatotoxicity in this model is not known. Utilizing pharmacological and genetic strategies, we evaluated the contribution of fibrinogen and two distinct receptors for thrombin, protease-activated receptor-1 (PAR-1) and PAR-4, in a model of acute ANIT hepatotoxicity. ANIT administration (60 mg/kg, po) caused a marked induction of the genes encoding the three fibrinogen chains (α, β, and γ) in liver, an increase in plasma fibrinogen, and concurrent deposition of thrombin-cleaved fibrin in liver. Partial depletion of circulating fibrinogen with ancrod did not impact ANIT hepatotoxicity. However, complete fibrin(ogen) deficiency significantly reduced serum alanine aminotransferase activity and hepatocellular necrosis in ANIT-treated mice. ANIT-induced hepatocellular necrosis was similar in PAR-1(-/-) mice compared with PAR-1(+/+) mice. Interestingly, the progression of ANIT-induced hepatocellular necrosis was significantly reduced in PAR-4(-/-) mice and by administration of an inhibitory PAR-4 pepducin (P4Pal-10, 0.5 mg/kg, sc) to wild-type mice 8 h after ANIT treatment. Interestingly, a distinct lesion, parenchymal-type peliosis, was also observed in PAR-4(-/-) mice treated with ANIT and in mice that were given P4Pal-10 prior to ANIT administration. The results suggest that fibrin(ogen), but not PAR-1, contributes to the progression of ANIT hepatotoxicity in mice. Moreover, the data suggest a dual role for PAR-4 in ANIT hepatotoxicity, both mediating an early protection against peliosis and contributing to the progression of hepatocellular necrosis.
Topics: 1-Naphthylisothiocyanate; Acute Disease; Animals; Blood Coagulation; Chemical and Drug Induced Liver Injury; Cholestasis; Disease Models, Animal; Female; Fibrinogen; Liver Function Tests; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Necrosis; Receptor, PAR-1; Receptors, Proteinase-Activated; Xenobiotics
PubMed: 20974703
DOI: 10.1093/toxsci/kfq327 -
Blood Mar 2019Platelets play a pivotal role in stimulating liver regeneration after partial hepatectomy in rodents and humans. Liver regeneration in rodents is delayed when platelets...
Platelets play a pivotal role in stimulating liver regeneration after partial hepatectomy in rodents and humans. Liver regeneration in rodents is delayed when platelets are inhibited. However, the exact mechanisms whereby platelets accumulate and promote liver regeneration remain uncertain. Thrombin-dependent intrahepatic fibrin(ogen) deposition was recently reported after partial hepatectomy (PHx) in mice, but the role of fibrin(ogen) deposits in liver regeneration has not been investigated. We tested the hypothesis that fibrin(ogen) contributes to liver regeneration by promoting intrahepatic platelet accumulation and identified the trigger of rapid intrahepatic coagulation after PHx. PHx in wild-type mice triggered rapid intrahepatic coagulation, evidenced by intrahepatic fibrin(ogen) deposition. Intrahepatic fibrin(ogen) deposition was abolished in mice with liver-specific tissue factor deficiency, pinpointing the trigger of coagulation after PHx. Direct thrombin activation of platelets through protease-activated receptor-4 did not contribute to hepatocyte proliferation after PHx, indicating that thrombin contributes to liver regeneration primarily by driving intrahepatic fibrin(ogen) deposition. Fibrinogen depletion with ancrod reduced both intrahepatic platelet accumulation and hepatocyte proliferation after PHx, indicating that fibrin(ogen) contributes to liver regeneration after PHx by promoting intrahepatic platelet accumulation. Consistent with the protective function of fibrin(ogen) in mice, low postoperative plasma fibrinogen levels were associated with liver dysfunction and mortality in patients undergoing liver resection. Moreover, increased intrahepatic fibrin(ogen) deposition was evident in livers of patients after liver resection but was remarkably absent in patients displaying hepatic dysfunction postresection. The results suggest a novel mechanism whereby coagulation-dependent intrahepatic fibrin(ogen) deposition drives platelet accumulation and liver regeneration after PHx.
Topics: Adult; Aged; Aged, 80 and over; Animals; Blood Coagulation; Female; Fibrinogen; Follow-Up Studies; Hepatectomy; Humans; Liver Diseases; Liver Regeneration; Male; Mice; Mice, Inbred C57BL; Middle Aged; Platelet Activation; Prognosis; Prospective Studies; Receptors, Thrombin; Thrombin; Thromboplastin
PubMed: 30655274
DOI: 10.1182/blood-2018-08-869057 -
European Archives of... Sep 2023Disturbance of cochlear microcirculation is discussed as final common pathway of various inner ear diseases. Hyperfibrinogenemia causing increased plasma viscosity is a... (Randomized Controlled Trial)
Randomized Controlled Trial
PURPOSE
Disturbance of cochlear microcirculation is discussed as final common pathway of various inner ear diseases. Hyperfibrinogenemia causing increased plasma viscosity is a possible factor for a critical reduction of cochlear blood flow that might lead to sudden sensorineural hearing loss (SSHL). The aim was to determine the efficacy and safety of drug-induced defibrinogenation by ancrod for SSHL.
METHODS
Double-blind, randomized, placebo-controlled, multicenter, parallel group, phase II (proof-of-concept) study (planned enrollment: 99 patients). Patients received an infusion of ancrod or placebo (day 1) followed by subcutaneous administrations (day 2, 4, 6). Primary outcome was the change in pure tone audiogram air conduction average until day 8.
RESULTS
The study was terminated early due to slow recruiting (31 enrolled patients: 22 ancrod, 9 placebo). A significant improvement of hearing loss was registered in both groups (ancrod: - 14.3 dB ± 20.4 dB, - 39.9% ± 50.4%; placebo: - 22.3 dB ± 13.7 dB, - 59.1% ± 38.0%). A statistically significant group-difference was not detected (p = 0.374). Placebo response of 33.3% complete and 85.7% at least partial recovery was observed. Plasma fibrinogen levels were reduced significantly by ancrod (baseline: 325.2 mg/dL, day 2: 107.2 mg/dL). Ancrod was tolerated well, no adverse drug reaction was of severe intensity, no serious adverse events occurred.
CONCLUSION
Ancrod reduced fibrinogen levels that support its mechanism of action. The safety profile can be rated positively. Since the planned number of patients could not be enrolled, no efficacy conclusion can be drawn. The high rate of placebo response challenges clinical trials for SSHL and needs to be considered in future investigations. Trial registrations This study was registered in the EU Clinical Trials Register, EudraCT-No. 2012-000066-37 at 2012-07-02.
Topics: Humans; Ancrod; Fibrinogen; Glucocorticoids; Hearing Loss, Sensorineural; Hearing Loss, Sudden; Treatment Outcome; Proof of Concept Study
PubMed: 36881166
DOI: 10.1007/s00405-023-07896-z -
Journal of Thrombosis and Haemostasis :... Apr 2017Essentials Immunity and coagulation are linked during sepsis but the role of thrombin is not fully elucidated. We investigated the effect of thrombin inhibition on...
UNLABELLED
Essentials Immunity and coagulation are linked during sepsis but the role of thrombin is not fully elucidated. We investigated the effect of thrombin inhibition on murine Klebsiella pneumosepsis outcome. Thrombin is crucial for survival and limiting bacterial growth in pneumonia derived sepsis. Thrombin improves host defense via fibrin and enhancement of platelet-neutrophil interactions.
SUMMARY
Background Innate immunity and coagulation are closely linked during sepsis. Their interaction can be detrimental to the outcome because of microvascular failure but can also enhance host defense. The role of thrombin therein has not been fully elucidated. Objective We aimed to investigate the contribution of thrombin to the host response during pneumonia-derived sepsis. Methods Mice treated with the specific thrombin inhibitor dabigatran or control chow were infected with the common human sepsis pathogen Klebsiella (K.) pneumoniae via the airways. In subsequent infection experiments, mice were additionally treated with ancrod to deplete fibrinogen. Ex vivo Klebsiella growth was assessed by incubating human whole blood or specific blood components in various conditions with Klebsiella. Results Thrombin inhibition by dabigatran enhanced bacterial outgrowth and spreading, and accelerated mortality. Thrombin inhibition did not influence neutrophil recruitment to the lung or activation or neutrophil extracellular trap formation. Dabigatran reduced D-dimer formation and fibrin deposition in the lung. Fibrin depletion also enhanced bacterial outgrowth and spreading, and thrombin inhibition had no additional effect. Both thrombin and fibrin polymerization inhibited ex vivo Klebsiella outgrowth in human whole blood, which was neutrophil dependent, and the effect of thrombin required the presence of platelets and platelet protease activated receptor-1. In vivo thrombin inhibition reduced platelet-neutrophil complex formation and endothelial cell activation, but did not prevent sepsis-induced thrombocytopenia or organ damage. Conclusions These results suggest that thrombin plays an important role in protective immunity during pneumonia-derived sepsis by fibrin polymerization and enhancement of platelet-neutrophil interactions.
Topics: Animals; Blood Coagulation; Blood Platelets; Cell Communication; Dabigatran; Extracellular Traps; Female; Fibrin; Fibrinogen; Flow Cytometry; Humans; Immune System; Immunity, Innate; Klebsiella Infections; Klebsiella pneumoniae; Lung; Mice; Mice, Inbred C57BL; Microcirculation; Neutrophils; Pneumonia, Bacterial; Sepsis; Thrombin
PubMed: 28092405
DOI: 10.1111/jth.13625 -
Kidney International Jan 1990The effect of ancrod, a defibrinating agent, on murine lupus glomerulonephritis in the male BXSB mouse was studied to determine the relationship between macrophage...
The effect of ancrod, a defibrinating agent, on murine lupus glomerulonephritis in the male BXSB mouse was studied to determine the relationship between macrophage procoagulant activity (PCA), fibrin deposition and glomerulonephritis. Marked renal disease and fibrin deposition were noted by three months of age in control mice, whereas little or no disease was seen in ancrod treated mice until five months of age. Similar high titers of anti-DNA antibodies and renal deposition of IgG were seen in both groups of mice. PCA rose with age in both ancrod treated and untreated mice, although it was significantly higher in control animals than in the ancrod treated group. Furthermore, ancrod therapy resulted in a decrease in plasma PCA inducing activity (PIF) and a decrease in the effectiveness of PIF to induce PCA in peritoneal macrophages in vitro. No mortality was observed in the 20 ancrod treated mice, whereas 10 of 20 control animals died. We conclude that defibrination with ancrod delays the development of renal fibrin deposition and glomerulonephritis and improves survival in BXSB mice. This was associated with a decrease in plasma PCA inducing activity and with an inhibitory effect on PCA induction. These results suggest that PCA contributes to injury in murine lupus glomerulonephritis by promoting fibrin deposition.
Topics: Ancrod; Animals; Blood Coagulation Factors; Fibrin; Fibrinogen; Lupus Nephritis; Macrophages; Male; Mice; Time Factors
PubMed: 2299806
DOI: 10.1038/ki.1990.4 -
The American Journal of Pathology Apr 2006Decreased fibrinolytic function favors the development of pulmonary fibrosis. Thrombin-activatable fibrinolysis inhibitor (TAFI) is a strong suppressor of fibrinolysis,... (Comparative Study)
Comparative Study
Decreased fibrinolytic function favors the development of pulmonary fibrosis. Thrombin-activatable fibrinolysis inhibitor (TAFI) is a strong suppressor of fibrinolysis, but its role in lung fibrosis is unknown. Therefore, we compared bleomycin-induced lung fibrosis in TAFI-deficient, heterozygous, and wild-type mice. The animals were sacrificed 21 days after bleomycin administration, and markers of lung fibrosis and inflammation were measured. The bronchoalveolar lavage fluid levels of total protein, neutrophil proteases (elastase, myeloperoxidase), cytokines (tumor necrosis factor-alpha, interleukin-13), chemokine (monocyte chemoattractant protein-1), coagulation activation marker (thrombin-antithrombin complex), total soluble collagen, and growth factors (platelet-derived growth factor, transforming growth factor-beta1, granulocytic-macrophage growth factor) were significantly decreased in knockout mice compared to wild-type mice. Further, histological findings of fibrosis, fibrin deposition, and hydroxyproline and collagen content in the lung were significantly decreased in knockout mice compared to wild-type mice. Depletion of fibrinogen by ancrod treatment led to equalization in the amount of fibrosis and collagen deposition in the lungs of knockout and wild-type mice. No difference was detected in body temperature or arterial pressure between the different mouse phenotypes. These results suggest that the anti-fibrinolytic activity of TAFI promotes lung fibrosis by hindering the rate at which fibrin is degraded.
Topics: Animals; Antithrombin III; Bleomycin; Blood Pressure; Body Temperature; Bronchoalveolar Lavage Fluid; Carboxypeptidase B2; Collagen; Cytokines; Fibrin; Fibrinogen; Growth Substances; Hydroxyproline; Lung; Mice; Mice, Knockout; Pancreatic Elastase; Peptide Hydrolases; Peroxidase; Pulmonary Fibrosis
PubMed: 16565485
DOI: 10.2353/ajpath.2006.050610 -
The American Journal of Pathology Jun 2012Hepatic fibrin(ogen) has been noted to occur after acetaminophen (APAP)-induced liver injury in mice. Deficiency in plasminogen activator inhibitor-1 (PAI-1), an...
Hepatic fibrin(ogen) has been noted to occur after acetaminophen (APAP)-induced liver injury in mice. Deficiency in plasminogen activator inhibitor-1 (PAI-1), an endogenous inhibitor of fibrinolysis, increases APAP-induced liver injury in mice. However, the roles of fibrinogen and fibrinolysis in APAP-induced liver injury are not known. We tested the hypothesis that hepatic fibrin(ogen) deposition reduces severity of APAP-induced liver injury. APAP-induced (300 mg/kg) liver injury in mice was accompanied by thrombin generation, consumption of plasma fibrinogen, and deposition of hepatic fibrin. Neither fibrinogen depletion with ancrod nor complete fibrinogen deficiency [via knockout of the fibrinogen alpha chain gene (Fbg(-/-))] affected APAP-induced liver injury. PAI-1 deficiency (PAI-1(-/-)) increased APAP-induced liver injury and hepatic fibrin deposition 6 hours after APAP administration, which was followed by marked hemorrhage at 24 hours. As in PAI-1(-/-) mice, administration of recombinant tissue plasminogen activator (tenecteplase, 5 mg/kg) worsened APAP-induced liver injury and hemorrhage in wild-type mice. In contrast, APAP-induced liver injury was reduced in both plasminogen-deficient mice and in wild-type mice treated with tranexamic acid, an inhibitor of plasminogen activation. Activation of matrix metalloproteinase 9 (MMP-9) paralleled injury, but MMP-9 deficiency did not affect APAP-induced liver injury. The results indicate that fibrin(ogen) does not contribute to development of APAP-induced liver injury and suggest rather that plasminogen activation contributes to APAP-induced liver injury.
Topics: Acetaminophen; Alanine Transaminase; Animals; Antithrombin III; Blood Coagulation; Chemical and Drug Induced Liver Injury; Drug Synergism; Fibrin; Fibrinogen; Fibrinolysis; Hemorrhage; Liver; Male; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Peptide Hydrolases; Plasminogen Activators; Serpin E2; Thrombin; Tissue Plasminogen Activator
PubMed: 22507835
DOI: 10.1016/j.ajpath.2012.02.011