Roles of Coagulation Pathway and Factor Xa in the Progression of Diabetic Nephropathy in db/db Mice

Abstract

The active type of coagulation factor X (factor Xa) activates various cell-types through protease-activated receptor 2 (PAR2). We previously reported that a factor Xa inhibitor could suppress Thy-1 nephritis. Considering that fibrin deposition is observed in diabetic nephropathy as well as in glomerulonephritis, this study examined the roles of the coagulation pathway and factor Xa in the development of diabetic nephropathy using type 2 diabetic model mice. Diabetic (db/db) and normoglycemic (m؉/m؉) mice were immunohistochemically evaluated for their expression/deposition of PAR2, transforming growth factor (TGF)-b b, fibrin, extracellular matrix (ECM) proteins, and CD31 at week 20. Significantly greater numbers of PAR2-positive cells and larger amounts of fibronectin, and collagen IV depositions were observed in the glomeruli of db/db mice than those in m؉/m؉ mice. Next, expression of PAR2 versus deposition of collagen IV and fibronectin was compared between week 20 and week 30, and the number of PAR2-positive cells in the glomeruli decreased in contrast with the increased accumulation of ECM proteins. In an intervention study, fondaparinux, a factor Xa inhibitor, was subcutaneously administered for ten weeks from week 10 to 20. Fondaparinux treatment significantly suppressed urinary protein, glomerular hypertrophy, fibrin deposition, expression of connective tissue growth factor, and ECM proteins deposition together with CD31-positive capillaries. These results suggest that coagulation pathway and glomerular PAR2 expression are upregulated in the early phase of diabetes, together with the increase of profibrotic cytokines expression, ECM proteins deposition and CD-31-positive vessels. Factor Xa inhibition may ameliorate glomerular neoangiogenesis and ECM accumulation in diabetic nephropathy.

Coagulation Factor Xa and Protease-Activated Receptor 2 as Novel Therapeutic Targets for Diabetic Nephropathy

“…PAR2 expression was also upregulated in the kidney of db/db mice. 29 Interestingly, immunoreactive PAR2, but not PAR1, was higher in biopsy specimens from patients with DN than in specimens from patients without DN. 30 These results support the importance of PAR2 in the pathogenesis of DN.…”

“…Fondaparinux, a FXa inhibitor, is suggested to reduce DN in db/db mice. 29 We extended this work using another DN model and identified connection between FXa and PAR2.…”

The emerging role of coagulation proteases in kidney disease

“…TF expression is increased in diabetic mice (db/db and streptozotocin models), along with increased expression of PAR2 (db/db mice show a transient increase at 20 weeks) and factor V 51,58 . Increased TF expression has been observed in tubular cells and glomerular parietal cells 51 , whereas glomerular thrombomodulin expression is reduced in diabetic mice 33 .…”

“…Furthermore, thrombin and factor Xa activate different receptors; hence anticoagulation with direct thrombin or factor Xa inhibitors might have distinct consequences. Thus, fondaparinux, a selective factor Xa inhibitor, conveys partially protective effects in db/db mice (that is, it has a minor effect on albuminuria and slightly reduces glomerular size), contrasting with the disadvantageous effects of hirudin 58,120 . Considering the increasing availability and use of small molecule anticoagulants, and the recent introduction of the first PAR-antagonist for clinical use, studies deciphering the effects of these new drugs on glomerular function and renal disease are needed.…”

Effects of high glucose on integrin activity and fibronectin matrix assembly by mesangial cells

“…Significant increases in FN have been detected in several glomerulopathies, including DN (Dixon et al. , 1980; Sumi et al. , 2011), and FN is one of the first ECM proteins to increase in the early stages of DN (Falk et al.…”