Urinary fibrin/fibrinogen degradation products measured using an anti-fibrinogen antibody predict orthostatic proteinuria.

BACKGROUND: The aim of this study was to assess the diagnostic value of urinary fibrin/fibrinogen degradation products (uFDP) measured using an anti-fibrinogen antibody in patients with orthostatic proteinuria (OP), and their use in differentiating between OP and glomerulonephritis (GN). METHODS: uFDP were measured using first urine in the morning (supine) and non-first urine during a hospital visit (upright) and then normalized to urine creatinine (uFDP/Cr, ng/mgCr). We compared (i) OP patients (n = 16); (ii) those in remission from nephrotic syndrome (NS, n = 14) and from GN (IgA nephropathy [IgAN], n = 14; Henoch-Schönlein purpura nephritis [HSPN], n = 12); and (iii) those with active GN (IgAN, n = 12; HSPN, n = 19). RESULTS: The uFDP/Cr ratio increased from supine to upright urine in patients with OP (P < 0.001), but decreased in one case. uFDP were excreted in supine urine in 94% of OP patients, with no excretion in NS remission patients or in 92% of GN remission patients (P < 0.001 for both). uFDP/Cr in supine urine was similar between the OP and active GN patients (P = 0.40), whereas proteinuria in supine urine was in the normal range in all OP patients, but was significantly higher in upright urine in the OP patients (P < 0.001). In upright urine, urinary protein/creatinine ratio was significantly lower in patients with OP than in those with active GN (P = 0.005). A uFDP/Cr ratio cut-off of 1,108 ng/mgCr in upright urine correctly differentiated OP from active GN, with a sensitivity of 87.5% and a specificity of 100%. CONCLUSION: Comparison of uFDP levels in supine/upright urine can be reliable for diagnosing OP and for differentiating it from active GN.

Urinary prothrombin fragment 1+2 in patients with venous thrombosis and myocardial infarction.

Patients with venous-thromboembolism (VTE) and myocardial infarction (MI) have elevated prothrombin fragment 1+2 (F1+2) levels. In patients with postoperative VTE, urinary F1+2 (uF1+2) was higher than in individuals without VTE. To explore the relationship between plasma and uF1+2 we performed a pilot study in patients with thrombotic events and healthy controls. In 40 patients with VTE or MI, and 25 age- and sex-matched healthy controls, F1+2 and D-dimer levels were measured in urine and plasma within 48 h after diagnosis. In addition, in all subjects renal function was assessed. Plasma and uF1+2 levels were positively correlated. Compared to controls, patients with VTE had higher levels of both plasma F1+2 (271 vs 160 pmol L(-1), p < 0.05) and uF1+2 levels (38 vs 28 pmol L(-1)), the latter, however, was not statistically significant. Patients with acute MI had similar F1+2 levels as controls in both plasma and urine. Differences in urinary F1+2 levels could not be attributed to differences in concentrations of creatinine or albumin in spot urine samples. Overall, D-dimer and F1+2 levels in urine were extremely low in all groups.

Urinary pro-thrombotic, anti-thrombotic, and fibrinolytic molecules as biomarkers of lupus nephritis.

OBJECTIVE: This study evaluates the utility of urinary pro-thrombotic molecules such as tissue factor (TF), anti-thrombotic molecules such as tissue factor pathway inhibitor (TFPI), and fibrinolytic molecules such as plasmin and d-dimer as biomarkers of lupus nephritis (LN). METHODS: Urine samples from 113 biopsy-proven LN patients (89 active LN and 24 inactive LN), 45 chronic kidney disease patients, and 41 healthy controls were examined for d-dimer, plasmin, TF, and TFPI levels by ELISA. The area under the receiver operating characteristic curve (AUC) analysis, multivariate regression analysis, and Bayesian network analysis were performed to assess the diagnostic value of the assayed molecules in LN. RESULTS: Although urinary d-dimer, plasmin, TF, and TFPI were all elevated in active LN compared to all control groups, and correlated with rSLEDAI and SLICC RAS disease activity indices, urine plasmin emerged as the strongest independent predictor of eGFR and renal disease status, by multivariate regression analysis and Bayesian network analysis. Whereas urine plasmin discriminated active LN from inactive disease with an AUC of 0.84, the combination of urine plasmin and TFPI discriminated ALN from ILN with an AUC of 0.86, with both surpassing the specificity and positive predictive value of traditional markers such as anti-dsDNA and complement C3. CONCLUSION: Both thrombogenic and thrombolytic cascades appear to be upregulated in lupus nephritis, with proteins from both cascades appearing in the urine. Of the coagulation cascade proteins surveyed, urine plasmin emerges as the strongest predictor of eGFR and clinical renal disease in patients with LN.

[Clinical implication of urine test for markers of endothelial dysfunction and angiogenesis factors in assessment of tubulointerstitial fibrosis in chronic glomerulonephritis].

AIM: To evaluate contribution of endothelial dysfunction and impairment of endothelial proliferation/ regeneration to mechanisms of development of tubulointerstitial fibrosis (TIF) in chronic glomerulonephritis (CGN) basing on urinary levels of markers of endothelial activation/impairment and angiogenesis factors. MATERIAL AND METHODS: A total of 67 CGN patients entered the study: 19 patients with moderate urinary syndrome (group 1), 37 patients with nephrotic syndrome (group 2), 11 patients with nephrotic syndrome and persistent renal failure (RF). A control group consisted of 12 healthy subjects. The examination covered excretion with urine of Willebrand factor (WF), plasminogen activator inhibitor I (PAL-I), fibrin degradation products (FDP), vascular endothelial growth factor (VEGF). These values were compared with severity of fibrous changes in renal interstitium estimated by biopsy morphometry. RESULTS: CGN patients had signs of affection of parietal effects of vascular endothelium. In particular, increased excretion of functionally active WF, PAI-I and FDP correlating with activity/severity of CGN. The changes were especially noticeable in patients with progressive forms of CGN (with NS and RF). Patients with morphologically verified TIF (interstitial area more than 20%) excretion of endothelial dysfunction markers was higher than in CGN patients free of TIF In a progressive course of nephritis endothelial dysfunction deteriorates by endothelial proliferation/regeneration impairment as shown by reduced urinary excretion of angiogenic factor VEGF and parallel elevation of functionally active WF in urine of patients with severe forms of CGN. Combined contribution of endothelial dysfunction and angiogenesis impairment to mechanisms of TIF development is seen from these values relations with severity of creatinemia and fibrous alterations in tubulointerstitial tissues of the kidney. CONCLUSION: The results point to participation of endothelium in mechanisms promoting development of TIF and RF in CGN both in terms of endothelial dysfunction and impairment of endothelial repair capacity. Clinicomorphological comparisons confirm the significance of WF, PAI-I and VEGF in assessment of local-renal endothelial changes and severity of fibrosis in renal tissue in CGN. Due to availability of the study material, perspectives of fibrogenesis monitoring in the kidneys with the tests appear which is essential for making prognosis and treatment policy in CGN patients.

Thrombin Generation in Patients With Suspected Venous Thromboembolism.

Increasing number of patients with clinically suspected venous thromboembolism is referred to radiological departments for definitive diagnosis. A simple assay to exclude the diagnosis and avoid radiological examinations is needed. We have reported correlations between D-dimer and prothrombin fragment 1 + 2 measured in plasma and urine. To further develop an analysis based on urine, more understanding of thrombin generation in these patients is needed. The aim of this study was to compare ex vivo thrombin generation with in vivo markers in plasma and urine in patients with and without venous thromboembolism. Urine and blood samples were collected from patients with suspected venous thromboembolism. Commercially available enzyme-linked immunosorbent assay (ELISA) kits were used to analyze the samples for in vivo thrombin generation. The ex vivo thrombogram parameters were measured by the calibrated automated thrombogram assay. Venous thromboembolism was verified with compression ultrasound of the lower extremity deep veins or with computer tomography of the pulmonary arteries. Venous thromboembolism was diagnosed in 117 of 591 patients, and they had significantly higher levels of urine and plasma prothromin fragment 1 + 2, D-dimer, lag time, time to peak, and endogenous thrombin potential when adjusted for covariates. The pattern of ex vivo and in vivo thrombin generation in patients with suspected venous thromboembolism was comparable when adjusted for covariates. Prothrombin fragment 1 + 2 in plasma and urine reflects thrombin generation ex vivo in the same manner. This indicates that urine may be an alternative substrate to quantify a procoagulant state.

Urine plasmin-like substances as an index of kidney allograft rejections.

Using solid state radioimmunoassays developed by the first author, changes in the urine level of plasmin-like substances (PLS) and fibrin degradation products (FDP) before and after human kidney transplantation were determined in 49 transplant patients. Averages of urine PLS and FDP in a normal population of 51 persons were 0.13+/-0.10 (SD) and 0.14+/-0.07 microng/ml, respectively. In all transplant patients there was an initial rise of both PLS and FDP in urine immediately after transplantation. This elevation peaked on days 4 and 5 and the PLS and FDP levels returned to normal range within 2 weeks in patients without evidence of rejeciton. A secondary rise of urine PLS was detected before or with a rise in serum creatinine in all of the patients experiencing rejections. Of 11 patients who showed a rejection episode within 2 weeks of transplantation, the secondary rise of urine PLS was detectable in 55% of the patients slightly before the serum creatinine level changes; of 6 patients with a rejection episode more than 2 weeks after transplantation, 100% showed a secondary PLS rise 6.7+/-2.3 (SE) days before the serum creatinine increased. The appearance of the secondary rise of urine FDP in the rejecting recipients was slightly later than the rise of PLS. Serial determination of urine PLS levels following human kidney transplantation appears to be an early index of rejections which occurs more than 2 weeks after transplantation, although the clinical usefulness of this measurement is probably limited.

Platelet function in experimentally induced pancreatitis in the dog.

Evidence suggests that changes in prostaglandins and disseminated intravascular coagulation accompany pancreatitis. Both may induce changes in platelet function. We wished to determine if experimentally induced pancreatitis in the dog was associated with altered platelet number and function, and whether there were concomitant changes in prostaglandins. Evidence for disseminated intravascular coagulation in the dogs with pancreatitis were red blood cell fragmentation, increased platelet turnover indicated by macro-platelets and the transient presence of fibrin degradation products in urine. There were no significant changes in platelet count. The platelets from dogs with pancreatitis showed a functional defect characterized by significantly decreased aggregation in response to adenosine diphosphate, arachidonic acid, and collagen. Release of adenosine triphosphate from platelets was reduced in collagen-stimulated aggregation. There were no changes in the plasma concentrations of thromboxane B2, 6-Keto-PGF1a, and PGE2. This defect may have been due to the generation of fibrin degradation products and platelet "exhaustion".

Antithrombin III and fibrinogen degradation product (fragment E) in diabetic nephropathy.

Plasma antithrombin III (AtIII), serum fragment E (FgE) and urine AtIII and FgE were measured in 25 diabetic patients with proteinuria above 1 g per day and compared to that in 25 patients with non-diabetic nephropathy, matched for the degree of proteinuria. Plasma AtIII concentrations were normal in both groups but FgE concentrations were increased. The level of plasma AtIII was directly related to HbA1 concentrations in the diabetics. For the same degree of proteinuria, the diabetic patients lost more AtIII and FgE in the urine. Urine AtIII was found to be mostly bound to activated procoagulants. Both urine AtIII and urine FgE correlated inversely with creatinine clearance. It was concluded that intraglomerular thrombosis probably contributes to the deteriorating renal function in diabetic nephropathy and is reflected in the concentrations of urine AtIII and FgE.

Further study of fibrinogen degradation products in bladder cancer detection.

A new, rapid immunoassay kit for assaying fibrinogen degradation products (FDP) was studied in 56 patients with cancer of the bladder and in 48 control patients. The specificity of the kit was demonstrated with a small number of false positive results. In bladder cancer patients with low-stage, small superficial tumors, FDP was positive in 32.2 per cent. The combination of urinary cytologic examination with FDP increased the accuracy of the positive results to 80 per cent. The rapid FDP test supplements the urinary cytology in the follow-up and detection of early bladder cancer.

Relationship between urinary fibrinogen degradation products and various types of chronic nephritis.

The concentration of urinary fibrin(ogen) degradation products (FDP) was determined by using enzyme immunoassay and radio immunoassay, and their urinary levels were compared with histologically classified types of glomerulonephritis. Urinary FDP levels were higher in the severe type of proliferative glomerulonephritis and at the active phase of systemic lupus erythematosus (SLE). They were also high in the membranous glomerulonephritis. Molecular weight of urinary FDP of a patient with severe proliferative glomerulonephritis was determined to be 150,000 and 68,000, respectively after gel filtration. Urinary FDP levels were higher in patients with glomerular fibrin deposit than in patients without fibrin deposit or normal volunteers. The amounts of excreted protein in urine was not related to the amounts of FDP. Decrease in the reciprocal of serum creatinine levels resulted in high urinary FDP levels, indicating that high urinary FDP levels may represent deterioration of renal function.

Fragments of urinary fibrin/fibrinogen degradation products and cross-linked fibrin degradation products in various renal diseases.

In children with several kinds of glomerular disease, fragments of fibrin/fibrinogen degradation products (FDP) and cross-linked fibrin degradation products (XLFDP) in the urine were investigated by autoradiography using western blotting method. Results were compared with selectivity of proteins observed in cases of proteinuria, or with histological findings. Patients with nephrotic syndrome exhibited slightly increased amount of urinary FDP, consisted mainly of X and Y fragments. On the other hand, in cases of proliferative glomerulonephritis, such as acute glomerulonephritis, purpura nephritis, Ig A nephropathy, systemic lupus erythematosus, or hemolytic uremic syndrome, increased FDP, including XLFDP, was detected in the urine. In these cases, FDP was consisted mainly of fragments X, Y, and D-dimer, and could not be correlated with the degree of mesangial proliferation or with urinary protein selectivity. It was concluded that the increased urinary FDP and XLFDP were derived not only from filtration of plasma fibrinogen or FDP, but also from fibrinolysis of intraglomerular fibrin deposits.

The utility of fibrin/fibrinogen degradation products in superficial bladder cancer.

Fibrin/fibrinogen degradation products are either absent or present at exceedingly low levels in the urine of healthy persons. Although various nonspecific inflammatory conditions of the urinary tract can result in detectable amounts of FDP in the urine, the presence of FDP is far more prevalent in urine from patients with bladder cancer. Urinary FDP levels tend to be higher in patients with tumors of increasing grade and stage. This correlation results in improved sensitivity in detecting more aggressive tumors. Current monoclonal antibody immunoassays are simple, rapid, and inexpensive, and can be performed on urine samples in the clinical setting. The overall accuracy of these immunoassays ranges from 75% to 80% (Table 1), suggesting that the urine FDP test should not be used alone for the surveillance of superficial bladder cancer. When assays for urine FDP are combined with urine cytology, the sensitivity for detecting tumors is improved. Prospective data are needed to determine whether using these tests in combination can safely permit a reduced frequency of endoscopic surveillance.

Urine cytology. It is still the gold standard for screening?

Urine cytology remains the gold standard for bladder cancer screening. It is the test against which all others are compared when evaluating potential bladder tumor markers. The answer to whether urine cytology possess the optimal combination of sensitivity and specificity to retain consideration as the best screening device depends on the goals of the clinical practice. Urine cytology has excellent specificity with few false-positive cases. Its overall sensitivity is poor, but this drawback is explained for the most part by poor criteria for identifying well-differentiated, low-grade TCC. The natural history of such lesions is the occurrence of multiple superficial recurrences in 70% to 80% of patients, with only a minority (10% to 15%) progressing to muscle invasive or metastatic disease. Because patients with low-grade TCC are at low risk for progression, they are monitored primarily for the development of a subsequent tumor. One might argue that the detection of new low-grade lesions is of secondary importance to the early detection of disease progression. The performance characteristics of urine cytology in this regard are much improved. Urine cytology often results in the identification of high-grade malignant cells even before a cystoscopically distinguishable gross lesion is present. Routinely diagnosing grade I TCC may be clinically irrelevant. Ancillary techniques to improve the sensitivity of urine cytology have been insufficiently additive to have much clinical value. Several promising bladder tumor markers have been investigated as potential screening tools and are summarized in Table 3. BTA, nuclear matrix proteins, and fibrin/fibrinogen degradation products share lower specificities than urine cytology and may have high rates of false positivity. Telomerase is highly sensitive and highly specific but is not readily available as a point-of-service test. Hyaluronidase and hyaluronic acid are promising prognostic markers, but hyaluronidase does not detect grade I TCC. Early results from studies of this marker await verification. Combining some of these new markers may optimize their performance status, allowing the advantages of one test to correct the shortcomings of another. Likewise, their combination with urine cytology may prove beneficial. Although adding urine cytology has not increased the sensitivity of some point-of-service tests, few studies have addressed the effect on specificity. Until an obvious winner is declared in the race to find a bladder tumor marker, urine cytology will remain the gold standard screening method because of its comfortable familiarity.

Comparison of urinary N-acetyl-beta-D-glucosaminidase and urinary fibrin degradation products for diagnosis of rejection after renal transplantation.

A comparison was made of two established tests to see which was the better indicator of rejection after renal transplantation. Daily urine samples were assayed for excretion of N-acetyl-beta-D-glucosaminidase (NAG) and fibrin degradation products (FDP). Twenty-five rejection episodes were studied in 19 patients. Both indicators tended to move in parallel. NAG was more often elevated in rejection, namely in 96% of rejection episodes as against 76% for FDP, FDP had the advantage of fewer false positive results and when it correctly indicated rejection its increase above the baseline was relatively greater than for NAG, NAG and FDP can both provide early warning of rejection. NAG is preferred for its ease of assay. Assays are performed daily and are of practical value in clinical management. The results of assays must be interpreted in conjunction with all relevant information.

Urine fibrin degradation products in detection and management of acute and chronic renal transplant rejection.

Detection of rejection by serial determinations of urine FDP using the latex agglutination slide test proved to be a reliable, simple and inexpensive method. In the absence of infection, clinical and biochemical acute rejection was preceded by a two-titer rise in excretion of urine FDP in 80% of 26 patients studied. It was not useful in predicting rejection in 44 stable long-term allograft recipients, although persistent elevation of urine FDP after anti-rejection therapy in these patients or those in the immediate post-transplant period implies ongoing rejection. Maintenance immunosuppression should be continued in these patients, but repeated high-dose steroid therapy should be limited because of their poor-term prognosis. Persistent increase in urine FDP may allow selection of those patients who would benefit from a trial of anticoagulant or antiplatelet therapy.

Urinary fibrinogen degradation products and differential protein clearances in renal disease.

The close correlation observed between urine concentration of fibrinogen degradation products and differential protein clearances in the proteinuria of renal disease has been confirmed. Heavy proteinuria in excess of 5 g/l however leads to raised FDP levels, irrespective of the selectivity of the protein clearance. A correction factor for proteinuria enables an accurate estimate of protein clearance from a single measurement of urine FDP.

Significance of urinary fibrin/fibrinogen degradation products (FDP) D-dimer measured by a highly sensitive ELISA method with a new monoclonal antibody (D-D E72) in various renal diseases.

To diagnose the abnormalities of coagulation-fibrinolysis in various renal diseases, we developed a new monoclonal antibody (D-D E72) against fibrin/fibrinogen degradation products D-dimer (FDP D-dimer) and established a highly sensitive enzyme-linked immunosorbent assay (ELISA) for its measurement. FDP D-dimer was assessed in 102 patients with various renal diseases, and the following results were obtained: 1. The mean level of urinary FPD D-dimer in 32 normal controls was 0.69 +/- 0.60 ng/ml (mean +/- SD). 2. The level of urinary FDP D-dimer was significantly higher in primary nephrotic syndrome group (NS), chronic renal failure group (CRF) and in the group of diabetic nephropathy (DM) than in the control group. However, no difference was observed in the level of urinary FDP D-dimer between non-nephrotic chronic glomerulonephritis group (CGN) and control group. 3. No significant correlation was revealed between D-dimer and urinary protein in CGN and NS groups. These results suggest that in addition to plasma filtration the urinary FDP D-dimer in NS, CRF and DM may be also related to abnormalities of secondary fibrinolysis in intra-glomerular fibrin deposits.

Significance of urinary excretion of fibrin degradation products during treatment of glomerulonephritis.

189 patients with various types of glomerular disease were studied. Creatinine clearance, protein excretion and urinary excretion of fibrin degradation products (FDPs) were measured before and at various intervals (up to 42 months) after starting treatment with indomethacin, alone or in combination with other drugs. The following observations were made: a. Patients with a urinary FDP in excess of 2 mg/24 hours before treatment had a significantly lower creatinine clearance and a significantly higher protein excretion than patients excreting less than 2 mg FDP/24 hours, indicating that FDP excretion reflects the severity of the renal disease. b. During treatment, the incidence of high FDP excretion decreases progressively, but remains high in patients who ultimately develop renal insufficiency. c. There is no correlation between the initial value of FDP excretion and the subsequent changes in creatinine clearance and proteinuria during treatment. This implies either that the initial FDP excretion has no prognostic value or, perhaps more likely, that disease activity is modified by treatment. d. The best correlation between FDP excretion and evolution is found in proliferative glomerulonephritis. There are reason to suppose that, in this group at least, the treatment influenced the evolution of the disease.

Urinary cross-linked fibrin degradation products in glomerular disease with crescents.

The concentration of cross-linked fibrin degradation products (XLFDP) in urine were determined by enzyme-linked immunosorbent assay (ELISA) or radioimmunoassay (RIA) in patients with several types of glomerulonephritis with crescents (CrGN). In patients with "active" cellular crescents, increased levels of XLFDP correlated with the percentage of glomeruli containing crescents. Dysmorphic erythrocytes, suggestive of glomerular bleeding, were observed in all of the patients with CrGN, and the urinary red cell counts (URCC) also correlated with percentage of glomeruli containing crescents. The absence of correlation between urinary XLFDP and URCC or urinary protein suggested that lysis of fibrin within crescents may contribute to the urinary excretion of XLFDP in CrGN. The measurement of urinary XLFDP in CrGN is likely to be of value in assessing the activity of glomerular lesions but not renal function.

Fibrinogen degradation products in acute renal failure of the newborn.

Acute parenchymal renal failure (ARF) in the newborn infant has emerged as a major problem since the advent of neonatal intensive care units. Because intravascular and/or intrarenal coagulation may be important in the development of ARF, a prospective study of coagulation was performed on 20 babies with ARF, with particular emphasis on the measurement of fibrinogen degradation products (FDP) in serum and urine. Thirteen babies with respiratory distress syndrome (RDS) and 40 healthy neonates served as controls. Initial serum FDP levels were significantly higher in ARF than in RDS or normals (P less than 0.001); initial urine FDP levels were higher in ARF than in normals (P less than 0.01). Levels of FDP did not differentiate among the various etiologies of ARF. Since initial urine FDP levels are high in normal newborns, serial urine FDP were compared among patient groups and found to be highest in ARF. Initial serum and urine FDP levels could not differentiate among the 11 survivors and 9 nonsurvivors, but FDP levels declined as the duration of ARF (e.g., survival) increased, often antedating the recovery of renal function. We conclude: (1) serum and urine FDP are significantly elevated in most newborns with ARF; (2) factors other than hypoxia may be involved in the pathogenesis of elevated serum FDP in RDS with ARF newborns, indicating the importance of coagulation; (3) serial measurements of serum and urine FDP may be early indicators of recovery of renal function.