Prophylaxis with AT III for thromboembolism in nephrotic syndrome: why should it be done?

Difficulty in managing nephrotic syndrome-associated cerebral venous thrombosis

Thromboembolism is one of the most serious complications of nephrotic syndrome (NS). Although the occurrence of renal vein thrombosis or deep vein thrombosis is well recognized in NS patients, they rarely develop cerebral venous thrombosis (CVT). The mortality rate of CVT patients is still approximately 10%, and 6-10% of patients who survive have a severe and permanent disability. Herein, we report the case of a 26-year-old woman with multiple thrombotic risk factors, including the presence of NS, use of oral contraceptives, smoking, and alcohol consumption who developed wide-range CVT. Undetermined fraction heparin, albumin and AT-III transfusion, and direct mechanical catheter thrombectomy were insufficient for the improvement of CVT. However, CVT eventually improved along with the remission of NS by prednisolone administration. This process indicates that in the management of CVT associated with NS, it is crucial to control the activity of NS. Currently, knowledge on the treatment for NS associated with CVT is limited, and this is a subject of urgent investigation.

SerpinC1/Antithrombin III in kidney-related diseases

The gene SerpinC1 encodes a serine protease inhibitor named antithrombin III (ATIII). This protease demonstrates both anticoagulant and anti-inflammatory action. ATIII is the most important coagulation factor inhibitor, and even minor changes in ATIII can significantly alter the risk of thromboembolism. ATIII can also suppress inflammation via a coagulation-dependent or -independent effect. Moreover, apart from ATIII deficiency, ATIII and its gene SerpinC1 may also be related to many diseases (e.g. hypertension, kidney diseases). The present review summarizes how ATIII affects the progress of kidney disease and its mechanism. Further studies are required to investigate how ATIII affects renal function and the treatment.

Hypercoagulable state evaluated by thromboelastography in patients with idiopathic membranous nephropathy

The aims of this study were to evaluate the characteristics of hypercoagulable states in patients with membranous nephropathy (MN) via thromboelastography (TEG) and to identify risk factors. 235 MN patients who had undergone TEG examinations from 2011 to 2014 were included. An abnormality in at least two TEG parameters is considered a hypercoagulable state. Patient data was compared between the hypercoagulable and non-hypercoagulable groups. Potential risk factors for hypercoagulability were analyzed by logistic regression models. Subgroup analysis was performed in hypercoagulable patients. Compared to the non-hypercoagulable MN patients, the hypercoagulable patients showed a significantly higher proportion of female patients, urinary protein, platelet count, triglyceride and fibrinogen level, along with more severe hypoproteinemia and a reduction of serum antithrombin III. Correlation analysis showed that hypoproteinemia was the primary risk factor for hypercoagulability in MN patients. Among the hypercoagulable MN patients, a subgroup TEG parameter analysis showed that glucocorticoids-used subgroup and smoker subgroup had shortened time to initial fibrin formation (R value) and increased coagulation index respectively (P < 0.05), indicating a more serious hypercoagulable state. Meanwhile, the time to initial fibrin formation (R value) and time to clot formation (K value) of the statin-used patients were remarkably higher than those of the non-statin patients. TEG examinations facilitated the detection of hypercoagulable states in MN patients, and hypoproteinemia was the most important risk factor for hypercoagulability in these patients. The use of glucocorticoids and smoking may help to aggravate hypercoagulable states, while statin drugs may alleviate hypercoagulability.

[Nephrotic syndrome revealed by pulmonary embolism: about four cases]

Nephrotic syndrom is an association of proteinuria>3g/d or 50mg/kg/d, an hypoalbuminemia<30g/L and a hypoproteinemia<60g/L. Primary etiologies are minimal glomerular injury, focal segmental glomerulosclerosis and non membranous glomerulonephritis. Secondary etiologies are diabetes, high blood pressure and amyloidosis. We present four cases about nephrotic syndrome after thromboembolic disease. In every case, patients show a pulmonary embolism symptomatic of a nephrotic syndrom, whose diagnostic could be delayed up to six months after first pulmonary symptoms. This raised the problem of renal biopsy in these patients who need anticoagulation. In minimal change nephrosis, without hematuria, high blood pressure or renal dysfonction, a corticosteroid therapy test could be done assuming that is corticosensitive minimal glomerular injury. In every case, anticoagulation course must be completed and maintained in case of patent nephrotic syndrom with an albuminemia under 20g/L. In case of pulmonary embolism or deep vein thrombosis, idiopathic-looking, a nephrotic syndrome must be sought-after. The two diagnosis ways are the proteinuria on the urine dipstick and the hypoproteinemia on usual biology. The main mechanism is the coagulation factor leak, side effect of the nephrotic syndrom, notably because of the antithrombin III.

Clinical syndromes associated with acquired antithrombin deficiency via microvascular leakage and the related risk of thrombosis

Antithrombin (AT) is a 65kDa glycoprotein belonging to a group of inhibitory factors known as serpins (serine protease inhibitors). It plays a critical role in the inhibition of coagulation and inflammation processes within the environment of the vascular endothelium. Inadequate levels of functional AT in plasma results in an increased risk of thrombotic events, both venous and arterial. AT deficiency can be inherited or acquired. Congenital AT deficiency is the most severe inherited thrombophilic condition with an odds ratio of 20 for the increased risk of venous thrombosis. Acquired AT deficiency occurs in a variety of physiologic and pathologic medical conditions with similar risks of increased thrombosis. In this article, we review clinical settings characterized by an acquired AT deficiency largely or partly subsequent to protein microvascular leakage. Other different mechanisms of AT depletion are implied in some clinical conditions together with endothelial loss, and, therefore, outlined. In addition, we provide a description of the current knowledge on the specific mechanisms underlying endothelial AT leakage and on the consequences of this protein decrease, specifically looking at thrombosis. We identify potential directions of research that might prove useful in patients with acquired AT deficiency.

Procoagulant activity of erythrocytes and platelets through phosphatidylserine exposure and microparticles release in patients with nephrotic syndrome

Recent studies showed that an imbalance of prothrombotic and antithrombotic factors and impaired thrombolytic activity contribute to the thrombophilia of the nephrotic syndrome (NS). However, it is not clear whether blood cell injury and/or activation is involved in hypercoagulability in NS patients. Our objectives were to study the increase in microparticle (MP) release and phosphatidylserine (PS) exposure on the outer membrane of MP-origin cells in NS patients, and to evaluate their procoagulant activity (PCA). The subjects were patients with membranous nephropathy (MN), minimal change nephrotic syndrome (MCNS) and healthy controls. Analyses of MPs and PS exposure were performed using a flow cytometer. PCA was determined by clotting time and purified coagulation complex assays. We found that lactadherin+ MPs, which derived from red blood cells (RBC), platelet and endothelial cell, increased in NS patients. Moreover, PS exposure on RBCs and platelets in each NS group, especially in MN, are higher than that in controls. MP shedding and PS exposure of RBCs/platelets were highly procoagulant in NS patients. However, blockade of PS with lactadherin inhibited over 90% of PCA while an anti-tissue factor antibody had no significant inhibition effect. Our results demonstrate that the thrombophilic susceptibility of NS may be partly ascribed to MP release and PS exposure of RBCs, platelets and endothelial cells. Lactadherin is a sensitive probe for PS that has high anticoagulant activity.