fibrin and Renal-Insufficiency

The clinical benefit of second-generation drug-eluting stents (2nd DES) has been established, compared to first-generation drug-eluting stents (1st DES). However, pathological response after 2nd DES implantation remains unclear, particularly in the Japanese population.. Using specimens obtained by autopsy, we compared the histology between 2nd DES (41 sections) and 1st DES (38 sections) lesions within 1 year after stent implantation to evaluate early tissue reaction in Japanese patients. Stent segments were fixed with 10% buffered formalin and embedded in plastic, followed by hematoxylin-eosin and Masson's trichrome staining. Ratio of covered stent struts was calculated, and the area of fibrin deposition was morphometrically evaluated. The degree of inflammation around struts was examined semi-quantitatively (score 0-3).. The ratio of covered struts and mean fibrin area of 2nd DES were 0.69±0.05 and 658.0±173.4μm. Histopathological analysis showed advanced healing process in 2nd DES compared with 1st DES lesions. These results are consistent with clinical beneficial outcome of 2nd DES implantation.

Topics: Aged; Aneurysm, Ruptured; Colitis, Ischemic; Coronary Vessels; Drug-Eluting Stents; Everolimus; Female; Fibrin; Heart Failure; Humans; Inflammation; Japan; Male; Middle Aged; Neointima; Pancreatitis; Pneumonia; Renal Insufficiency; Risk Factors; Sepsis; Sirolimus; Treatment Outcome

Carbamylation is a non-enzymatic post-translational modification induced upon exposure of free amino groups to urea-derived cyanate leading to irreversible changes of protein charge, structure and function. Levels of carbamylated proteins increase significantly in chronic kidney disease and carbamylated albumin is considered as an important biomarker indicating mortality risk. High plasma concentrations and long half-life make fibrinogen a prime target for carbamylation. As aggregation and cross-linking of fibrin monomers rely on lysine residues, it is likely that carbamylation impacts fibrinogen processing. In this study we investigated carbamylation levels of fibrinogen from kidney disease patients as well as the impact of carbamylation on fibrinogen cleavage by thrombin, fibrin polymerisation and cross-linking in vitro. In conjunction, all these factors determine clot structure and stability and thus control biochemical and mechanical properties. LC-MS/MS analyses revealed significantly higher homocitrulline levels in patient fibrinogen than in fibrinogen isolated from control plasma. In our in vitro studies we found that although carbamylation does not affect thrombin cleavage per se, it alters fibrin polymerisation kinetics and impairs cross-linking and clot degradation. In addition, carbamylated fibrin clots had reduced fiber size and porosity associated with decreased mechanical stability. Using mass spectroscopy, we discovered that N-terminally carbamylated fibrinopeptide A was generated in this process and acted as a strong neutrophil chemoattractant potentially mediating recruitment of inflammatory cells to sites of fibrin(ogen) turnover. Taken together, carbamylation of fibrinogen seems to play a role in aberrant fibrin clot formation and might be involved in haemostatic disorders associated with chronic inflammatory diseases.

Topics: Blood Coagulation; Chemotaxis, Leukocyte; Citrulline; Cyanates; Factor XIIIa; Fibrin; Fibrinogen; Fibrinolysis; Fibrinopeptide A; Humans; Kinetics; Neutrophils; Polymerization; Protein Conformation; Protein Processing, Post-Translational; Protein Stability; Renal Dialysis; Renal Insufficiency; Structure-Activity Relationship; Thrombin; Urea

Oral anticoagulant therapy (OAT) patients have international normalized ratio (INR) safety windows for oral surgery, the lower limit of which is determined by the thromboembolic risk, with the upper limit typically 3.0. We sought to assess whether these limits will also be true with comorbidities that favor bleeding, such as diabetes, liver disease, and chronic renal failure.. The study was designed for 500 consecutive extractions. Patients with an INR greater than 3.0 were switched to heparin and used as controls. The primary outcome was the incidence of bleeding with the need for reoperation, in connection with 3 principal predictors: the INR, reasons for OAT, and comorbidity type. Continuous variables were analyzed using the Mann-Whitney U test and categorical variables using χ2 or Fisher's exact test. Statistical significance was set at P < .05. The reliability of the INR as a bleeding predictor was assessed using receiver operating characteristic (ROC) curves.. Extractions in patients receiving OAT without comorbidities had a success rate of 99.7% against severe bleeding. Despite equivalent INR values, patients with comorbidities had a significantly lower rate (81.3%, P < .001). For these patients, the ROC curve procedure indicated lower INR upper limits, 2.8 for mechanical heart prosthesis subjects and 2.3 for all others. Among the comorbidities, diabetes was associated with the greatest frequency of bleeding (31%) compared with liver disease (15%) and kidney failure (11%).. Patients with comorbidities should be advised to bring their INR within narrower safety windows (upper limit of 2.5 to 2.8 for mechanical prosthesis and 2.0 to 2.3 otherwise) or be switched to heparin. Alternatively, we propose applying to the socket, a platelet-rich growth factor preparation to foster hemostasis.

Topics: Adult; Aged; Aged, 80 and over; Anticoagulants; Area Under Curve; Chronic Disease; Diabetes Complications; Female; Fibrin; Follow-Up Studies; Heart Valve Prosthesis; Hematoma; Hemostatics; Heparin; Humans; International Normalized Ratio; Liver Diseases; Male; Middle Aged; Oral Hemorrhage; Postoperative Hemorrhage; Prospective Studies; Renal Insufficiency; ROC Curve; Thromboembolism; Tooth Extraction; Tooth Socket; Treatment Outcome; Young Adult

The microvascular endothelium of the kidney glomerulus is injured in Shiga-like toxigenic bacterial infection, genetic or acquired loss of complement regulatory protein function, and allo-immune responses of solid-organ or bone marrow transplantation. Existing models of diseases with glomerular endothelial cell (EC) injury, collectively grouped as thrombotic microangiopathies, are problematic, impeding investigation of the mechanisms of microvascular defense and repair. To develop a model of glomerular endothelial injury in the mouse, we conjugated the M. oreades lectin to the cytotoxin, saporin, (LS) to selectively injure the glomerular endothelium. Injury of the microvasculature was evaluated by light, immunofluorescence, and electron microscopy, and by quantitative RT-PCR of cell-type specific transcripts. Renal function was evaluated by quantitation of serum creatinine. The toxin conjugate induced apoptosis of microvascular ECs in vitro, and subtle histologic features of thrombotic microangiopathy in vivo that were enhanced by co-injection of 50 μg/kg LPS. Among LS/LPS-treated animals, loss of glomerular EC staining correlated with decreased expression of EC-specific transcripts, and impaired kidney function. Selective injury of the glomerular microvasculature with LS toxin conjugate and LPS elicits histologic features of thrombotic microangiopathy and acute kidney failure.

Topics: Animals; Apoptosis; Disease Models, Animal; Endothelium, Vascular; Female; Fibrin; Kidney Glomerulus; Mice; Microvessels; Renal Insufficiency; Thrombosis

Activity of plasma proteolytic systems (fibrin formation, fibrinolysis, and anticoagulant system) and the possibility for correction of changes in these systems with erythropoietin were studied in experiments on outbred albino rats with experimental renal failure. Renal failure was induced by a single subcutaneous injection of mercury chloride (II). The parameters were estimated on day 5 postinjection. Erythropoietin in a single dose of 5000 U/kg was administered on day 4. Renal failure was accompanied by activation of fibrin formation (with factors of the common and intrinsic pathways of blood coagulation), increase in antithrombin activity, and inhibition of the fibrinolytic system. Treatment with erythropoietin led to partial recovery of fibrin formation and fibrinolysis. Under analytical in vitro conditions, 30-min incubation of whole blood from healthy donors with erythropoietin in doses of 1.9-30.0 U/liter was followed by a dose-dependent inhibition of the fibrin formation system and activation of fibrinolysis.

Topics: Animals; Blood Coagulation; Erythropoietin; Fibrin; Fibrinolysis; Humans; Male; Random Allocation; Rats; Renal Insufficiency

We investigated a patient with atypical hemolytic uremic syndrome without diarrhea to determine the presence of antibodies and the specificity of the related antigens. The patient experienced repeated episodes of hemolytic uremic syndrome. She is dialysis dependent. von Willebrand factor (vWF), vWF multimers, platelet aggregation, ADAMTS-13 activity and platelet immunoblots were determined. During acute episodes vWF increased threefold, with unusually large vWF multimers on two occasions. Platelet aggregation was normal but the plasma caused spontaneous aggregation of normal platelets. Reactivity was removed after absorption with protein A. Protein blotting against platelet and microvascular endothelial cells showed strong and persistent reactivity against antigens of 200 and 55 kDa. Two-dimensional immunoblots of the whole platelet proteome and incubation with plasma identified strong immunoreactivity with two target spots in the 55-kDa area. Mass spectroscopy confirmed the target as beta-fibrin, molecular weight 50.73 kDa, isoelectric point 7.95, with MASCOT scores of 859 and 750, Two years after presentation another band was detected at 66 kDa and identified as the alpha subunit of fibrin. This patient's plasma contained a platelet-aggregating factor that was removed by immunoglobulin absorption. She developed antibodies against the alpha and beta subunits of fibrin/fibrinogen.

Topics: ADAM Proteins; ADAMTS13 Protein; Adolescent; Antigen-Antibody Reactions; Autoantibodies; Blood Platelets; Female; Fibrin; Fibrinogen; Hemolytic-Uremic Syndrome; Humans; Immunoglobulin G; Platelet Aggregation; Recurrence; Renal Insufficiency; von Willebrand Factor

Percutaneous transluminal renal angioplasty and stent placement with use of a coronary protection device was performed in a total of four patients with hypertension (n = 4) and/or renal insufficiency (n = 3) referred for revascularization of five renal arteries. Renal revascularization was successful in all five renal arteries (100%), but renal revascularization under protection by the FilterWire EX was achieved in only three of five renal arteries (60%). In one of these three, only a suboptimal seal was achieved between the vessel wall and the filter basket. Nevertheless, use of the device was safe and fibrin and/or cholesterol fragments were retrieved from three renal arteries. The FilterWire EX needs to be modified for the renal circulation to achieve the full theoretical advantages of these systems in this vascular bed.

Topics: Aged; Aged, 80 and over; Alloys; Angioplasty, Balloon; Cholesterol; Embolism; Female; Fibrin; Filtration; Humans; Hypertension; Male; Middle Aged; Polyurethanes; Renal Artery Obstruction; Renal Insufficiency; Retrospective Studies; Stents; Treatment Outcome

Fibrin deposition is an important mechanism of glomerular injury in crescentic glomerulonephritis (GN), a severe form of immune renal injury. Both coagulation and fibrinolysis (via the plasminogen-plasmin system) are important in net glomerular fibrin accumulation in GN. alpha2-Antiplasmin (alpha2-AP) is the major circulating inhibitor of plasmin and is expressed in the renal tubulointerstitium.. To determine whether endogenous alpha2-AP contributes to glomerular fibrin accumulation in GN.. Crescentic autologous phase antiglomerular basement membrane GN was induced in mice with intact and deficient endogenous alpha2-AP (alpha2-AP+/+ and alpha2-AP-/- mice).. In mice with crescentic GN, alpha2-AP was detected in the tubulointerstitium and in segmental deposits within some glomeruli. alpha2-AP+/+ mice developed crescentic GN (38 +/- 9% glomeruli affected) with glomerular fibrin deposition and renal impairment (serum creatinine 30 +/- 1 micro mol L-1, normal without GN 11 +/- 1 micro mol L-1). Genetic deficiency of alpha2-AP did not result in attenuated glomerular fibrin deposition, crescent formation (39 +/- 8% glomeruli affected), glomerular leukocyte infiltration or renal impairment (serum creatinine 33 +/- 7 micro mol L-1). alpha2-AP was unmeasurable in kidneys from alpha2-AP-/- mice, which did not develop compensatory changes in plasminogen, tissue type plasminogen activator (tPA), urokinase type PA (uPA) or plasminogen activator inhibitor-1 proteins, or changes in tPA or uPA activity. alpha2-AP-/- mice did have enhanced total renal fibrinolytic capacity as assessed by in situ fibrin overlay (alpha2-AP+/+ 0.19 +/- 0.01, alpha2-AP-/- 0.36 +/- 0.03 lyzed area/total area).. alpha2-AP is not important to net glomerular fibrin deposition, crescent formation or renal impairment in crescentic GN.

Topics: alpha-2-Antiplasmin; Animals; Chemotaxis, Leukocyte; Fibrin; Fibrinolysis; Glomerulonephritis; Kidney Glomerulus; Mice; Mice, Knockout; Renal Insufficiency

Increased glomerular tissue factor (TF) expression is associated with glomerular fibrin deposition and renal failure in human and experimental crescentic glomerulonephritis (GN). However, the in vivo functional contribution of TF to the development of glomerular fibrin deposition, crescent formation, and renal failure in GN has not been established. The contribution of TF to fibrin deposition and renal injury was studied in a rabbit model of crescentic GN in which glomerular macrophage infiltration, augmented TF expression, and fibrin deposition are prominent. Administration of anti-TF antibody inhibited glomerular TF activity in nephritic glomeruli by 96%, without affecting macrophage accumulation or systemic indices of coagulation. Anti-TF antibody significantly reduced glomerular fibrin deposition (fibrin scores, 0.43 +/- 0.10 (treated) and 1.40 +/- 0.19 (control); P < 0.0005), crescent formation (0.33 +/- 0.05 (treated) and 1.0 +/- 0.06 (control); P < 0.0005), and development of renal failure (serum creatinine, 168 +/- 22 mumol/l (treated) and 267 +/- 35 mumol/l (control); P < 0.04). This was associated with significant reduction in proteinuria (1189 +/- 277 mg/24 hours (treated) and 2060 +/- 336 mg/24 hours (control); P < 0.03) and expression of MHC class II antigen in glomeruli (1.25 +/- 0.41 (treated) and 2.83 +/- 0.53 (control); P < 0.03) and in tubules and interstitial areas. These data demonstrate that TF is the major in vivo initiator of fibrin deposition in crescentic GN. The reduction in proteinuria and glomerular major histocompatibility class II antigen expression by TF inhibition suggests that TF may also activate other mediators that contribute to glomerular injury.

Topics: Animals; Antibodies; Blood Coagulation; Fibrin; Glomerulonephritis; Histocompatibility Antigens Class II; Immunoconjugates; Kidney Glomerulus; Male; Proteinuria; Rabbits; Renal Insufficiency; Thromboplastin

The plasminogen/plasmin system has the potential to affect the outcome of inflammatory diseases by regulating accumulation of fibrin and other matrix proteins. In human and experimental crescentic glomerulonephritis (GN), fibrin is an important mediator of glomerular injury and renal impairment. Glomerular deposition of matrix proteins is a feature of progressive disease. To study the role of plasminogen and plasminogen activators in the development of inflammatory glomerular injury, GN was induced in mice in which the genes for these proteins had been disrupted by homologous recombination. Deficiency of plasminogen or combined deficiency of tissue type plasminogen activator (tPA) and urokinase type plasminogen activator (uPA) was associated with severe functional and histological exacerbation of glomerular injury. Deficiency of tPA, the predominant plasminogen activator expressed in glomeruli, also exacerbated disease. uPA deficiency reduced glomerular macrophage infiltration and did not significantly exacerbate disease. uPA receptor deficiency did not effect the expression of GN. These studies demonstrate that plasminogen plays an important role in protecting the glomerulus from acute inflammatory injury and that tPA is the major protective plasminogen activator.

Topics: Animals; Fibrin; Glomerulonephritis; Kidney; Kidney Glomerulus; Mice; Mice, Mutant Strains; Plasminogen; Renal Insufficiency; Tissue Plasminogen Activator; Urokinase-Type Plasminogen Activator