Myostatin Exacerbates Endothelial Dysfunction Induced by Uremic Toxin Indoxyl Sulfate and Is Associated with Hemodialysis Arteriovenous Access Complications

Hemodialysis patients exhibit endothelial dysfunction, contributing to elevated cardiovascular risk and complications of the arteriovenous access. These patients have elevated serum levels of myostatin, a member of the transforming growth factor-β (TGFβ) superfamily, and of the uremic toxin indoxyl sulfate, both of which are pro-inflammatory towards endothelial cells. We hypothesized that myostatin and indoxyl sulfate may synergistically induce endothelial dysfunction by impairing endothelial proliferation and promoting a pro-inflammatory phenotype. We first investigated the effect of myostatin on cultured endothelial cells in the presence of indoxyl sulfate. We then examined the association between serum myostatin concentrations and the occurrence of cardiovascular and arteriovenous access complications in hemodialysis patients. In vitro, myostatin exhibited endotheliotoxic effects in the presence of a uremic concentration of indoxyl sulfate, enhanced its antiproliferative effect, and amplified MCP-1 and IL-8 chemokine upregulation. In patients, high myostatin concentrations correlated with indoxyl sulfate concentrations and were associated with an increased risk of arteriovenous access complications. These findings suggest that myostatin amplifies endothelial injury mediated by indolic uremic toxins and might contribute to AV access complications.