Disease Severity Correlates with Thrombotic Capacity in Experimental Nephrotic Syndrome

Abstract

Thrombotic disease, a major life-threatening complication of nephrotic syndrome, has been associated with proteinuria and hypoalbuminemia severity. However, it is not fully understood how disease severity correlates with severity of the acquired hypercoagulopathy of nephrotic syndrome. Without this knowledge, the utility of proteinuria and/or hypoalbuminemia as biomarkers of thrombotic risk remains limited. Here, we show that two well established ex vivo hypercoagulopathy assays, thrombin generation and rotational thromboelastometry, are highly correlated with proteinuria and hypoalbuminemia in the puromycin aminonucleoside and adriamycin rat models of nephrotic syndrome. Notably, in the puromycin aminonucleoside model, hyperfibrinogenemia and antithrombin deficiency were also correlated with proteinuria severity, consistent with reports in human nephrotic syndrome. Importantly, although coagulation was not spontaneously activated in vivo with increasing proteinuria, vascular injury induced a more robust thrombotic response in nephrotic animals. In conclusion, hypercoagulopathy is highly correlated with nephrotic disease severity, but overt thrombosis may require an initiating insult, such as vascular injury. Our results suggest that proteinuria and/or hypoalbuminemia could be developed as clinically meaningful surrogate biomarkers of hypercoagulopathy to identify patients with nephrotic syndrome at highest risk for thrombotic disease and potentially target them for anticoagulant pharmacoprophylaxis.

Nephrotic Syndrome May Be One of the Important Etiologies of Cerebral Venous Sinus Thrombosis

“…The severity of hypoalbuminaemia and proteinuria is notably positively correlated with the likelihood of venous thromboembolism, 7 and may be a clinically available, useful biomarker of hypercoagulopathy. 10 Generally, NS is regarded as a hypercoagulable status attributed to urinary loss of anticoagulant factors and platelet hyperaggregability. According to Farid et al, there was no difference in APTT between NS patients in relapse and patients in remission and healthy controls.…”

Nephrotic Syndrome-Associated Hypercoagulopathy is Alleviated by Nuclear Receptor Agonist Therapy with both Pioglitazone and Glucocorticoids

“…30 In order to further confirm the sensitivity of PAN-NS hypercoagulopathy to High-MP, we also investigated a range of proteinuria levels obtained by varying the PAN dose and administration route. 12,43 For these experiments we used six groups (n=4-6/ group) of male Wistar rats (weight ~150-200 g) which received a single dose of saline (n=8 controls) or PAN, 75 mg/kg via either tail vein (IV) or intraperitoneal (IP) injection, or 100 mg/kg IP. We also compared the effects of High-MP, Pio, and Pio+Low-MP treatment in a set of healthy rats not given PAN (n=4/group).…”

“…On day 11, the rats were anesthetized with 3% isoflurane and blood was collected from the inferior vena cava through a 23-G needle into a final concentration of 0.32% NaCitrate/1.45 µM Corn Trypsin Inhibitor (CTI; Haematologic Technologies Inc., Vermont, VT, USA), processed to Platelet Poor Plasma (PPP) as previously described, and stored at -80ºC until analyzed. 12 UPC was measured by Antech Diagnostics (Morrisville, NC), using standard techniques that are fully compliant with Good Laboratory Practice regulations. 12 Plasma albumin concentrations were determined using a bromocresol purple (BCP) assay (QuantiChrom BCP; BioAssay Systems, Hayward, CA).…”

“…12 UPC was measured by Antech Diagnostics (Morrisville, NC), using standard techniques that are fully compliant with Good Laboratory Practice regulations. 12 Plasma albumin concentrations were determined using a bromocresol purple (BCP) assay (QuantiChrom BCP; BioAssay Systems, Hayward, CA).…”

“…We have previously demonstrated, in animal models of NS, that disease severity (proteinuria and hypoalbuminemia) is tightly correlated with endogenous thrombin potential (ETP), a global measure of hypercoagulopathy that is predictive of VTE-risk, but not yet widely available for clinical use. [12][13][14][15][16][17][18][19][20][21][22][23] Therefore, proteinuria and serum albumin levels, which are routinely followed biomarkers of NS disease activity, may become useful surrogate markers of VTE-risk and thus guide clinical trials of anticoagulant prophylaxis in NS.…”