Sodium thiosulfate: new hope for the treatment of calciphylaxis

Calciphylaxis/calcific uremic arteriolopathy is rare but an important cause of morbidity and mortality in patients with chronic and end-stage kidney disease with increasing prevalence. Intravenous sodium thiosulfate (STS) has rapidly emerged from a seldom used therapy for the treatment of calciphylaxis/calcific uremic arteriolopathy to a treatment that is being increasingly utilized globally due to multiple positive outcomes shared in the form of case reports and reviews during the past 6 years. Its role as a rather potent antioxidant has uniquely been associated with a prompt decrease in pain and its slower chelating properties are associated with regression of subcutaneous calcifications. Excessive reactive oxygen species (ROS) activate nuclear transcription factor, NF(kappa)B and downstream cytokines resulting in inflammation, which may result in dysregulated hepatic protein synthesis. Indeed, inflammation activates acute-phase reactant synthesis, while concurrently inhibiting synthesis of fetuin-A (an inhibitor of extraosseous calcification) and the antioxidant albumin. Additionally, ROS may decrease locally synthesized matrix GLA proteins and this combination may contribute to increased vascular and subcutaneous calcification. STS used alone or in combination with other novel emerging therapies may result in the improved clinical outcomes in this challenging clinical condition.