Indoxyl sulfate induces platelet hyperactivity and contributes to chronic kidney disease–associated thrombosis in mice

Abstract

Key Points• Uremic solute IS increases platelet activity via activation of ROS/p38MAPK signaling.• Klotho counteracts ISinduced thrombosis by restraining platelet hyperactivity.Thrombosis is a common complication of chronic kidney disease (CKD), but the causes and mechanisms of CKD-associated thrombosis are not well clarified. Here, we show that platelet activity is remarkably enhanced in CKD mice, with increase of serum indoxyl sulfate (IS), a typical uremic toxin, which cannot be effectively cleared by routine dialysis. Ex vivo and in vitro experiments reveal that IS displays a distinct ability to enhance platelet activities, including elevated response to collagen and thrombin, increases in plateletderived microparticles, and platelet-monocyte aggregates. The flow chamber assay and carotid artery thrombosis model demonstrate that IS-induced platelet hyperactivity contributes to thrombus formation. Further investigations disclose that reactive oxygen species (ROS)-mediated p38MAPK signaling plays a key role in IS-induced platelet hyperactivity. Moreover, we show that Klotho, which is expressed dominantly in the kidneys, has the capacity to counteract IS-induced platelet hyperactivity by inhibiting ROS/p38MAPK signaling, whereas Klotho reduction may aggravate the effect of IS on platelet activation in CKD and klotho 1/2 mice. Finally, we demonstrate that Klotho protein treatment can protect against IS-induced thrombosis and atherosclerosis in apoE 2/2 mice. Our findings uncover the mechanism of platelet hyperactivity induced by IS and provide new insights into the pathogenesis and treatment of CKD-associated thrombosis.

High‐density lipoprotein from end‐stage renal disease patients exhibits superior cardioprotection and increase in sphingosine‐1‐phosphate

“…Because thrombocytes are a major source of S1P, our finding may be related to thrombocytes activation in ESRD . This was also recently confirmed in a murine CKD model, where thrombocyte activity was remarkably enhanced with increase in serum indoxyl sulphate, a typical uremic toxin …”

“…27 This was also recently confirmed in a murine CKD model, where thrombocyte activity was remarkably enhanced with increase in serum indoxyl sulphate, a typical uremic toxin. 28 Although higher plasma concentrations of S1P contribute to the significantly higher levels of the lipid associated with HDL, reduced albumin concentrations in the uremic milieu are also likely to contribute 29 . Whilst plasma S1P is principally associated with HDL, also albumin serves as a transport vector.…”

Targeting STUB1–tissue factor axis normalizes hyperthrombotic uremic phenotype without increasing bleeding risk

“…Although vessel wall factors and platelets in IS-mediated thrombosis are being examined (11, 18, 46), the roles of other metabolites (termed “thrombolome”) (3, 11), microvesicles, etc. remain to be probed to fully characterize the hyperthrombotic uremic milieu.…”

Integrative Bioinformatics Analysis Provides Insight into the Molecular Mechanisms of Chronic Kidney Disease

“…Our data suggest that abnormal platelet function may be a major contributor to the imbalance. Similarly, a recent study observed markedly enhanced platelet activity in CKD mice, which could be attenuated by inhibiting MAPK signaling via klotho administration [27]. Regarding hub genes, FN1 and ACTA2 are well documented key regulators of renal fibrosis.…”