Spironolactone dose‑dependently alleviates the calcification of aortic rings cultured in hyperphosphatemic medium with or without hyperglycemia by suppressing phenotypic transition of VSMCs through downregulation of Pit‑1

Abstract

Vascular calcification (VC) is highly prevalent in chronic kidney disease (CKD), especially in patients with end stage renal disease and is strongly associated with cardiovascular morbidity and mortality. Clinical observations have demonstrated that hyperphosphatemia and hyperglycemia can accelerate VC. Spironolactone (SPL) has been proven to improve cardiovascular outcomes in clinical trials and its protective effect on VC has been reported recently; however, the underlying mechanisms are not completely understood and require further investigation. Furthermore, the current CKD rat models that are used to research VC do not match well with the clinical characteristics of CKD patients. Aortic rings were obtained from male Sprague-Dawley rats, then cultured in different media with varying phosphorus and glucose concentrations to investigate the effects and the possible mechanisms, as well as the effective serum concentrations of SPL, on VC and type III sodium-dependent phosphate cotransporter-1 (Pit-1) expression. SPL dose-dependently alleviated VC by suppressing the phenotypic transition of vascular smooth muscle cell (VSMCs) through downregulation of Pit-1 in a high phosphorus medium and even in a high phosphorus combined with high glucose medium. The combined effects of hyperglycemia and hyperphosphatemia on the calcification of aortic rings ex vivo were demonstrated. In conclusion to the best of our knowledge, this article is the first report on the effective serum concentrations of SPL capable of protecting VSMCs from calcification and provides the first experimental evidence for the combined effects of hyperglycemia and hyperphosphatemia on VC of aortic rings. Additionally, the Pit-1 protein level may be a novel index for evaluating the magnitude of VC in CKD patients.

Research Models for Studying Vascular Calcification

“…Currently, aortic rings from rats and mice are commonly used for studying vessel calcification under various conditions. The stimulation time varies from 3-14 days [6,24,25,28,59,[62][63][64][65]. Although the utilization of aortic rings comes closer to the physiologic setting, a multitude of influencing factors is still lost.…”

Current Evidence and Future Perspectives on Pharmacological Treatment of Calcific Aortic Valve Stenosis

“…An alternative approach to reduce RAAS activation is the administration of mineralocorticoid receptor antagonists (eplerenone and spironolactone), used for the treatment of hypertension. Spironolactone has been shown to prevent vascular calcification in vitro and to improve CV clinical outcomes [118]; however, its effects have never been assessed in clinical trials involving patients with CAVS. Eplerenone has proven to halt the process of vascular calcification in vitro [119] and to exert an anti-atherosclerotic effect in vivo [120].…”

A New Disease Concept in the Age of Processed Foods—Phosphorus-Burden Disease; including CKD–MBD Concrete Analysis and the Way to Solution

“…Spironolactone was found to inhibit PiT-1-dependent vascular calcification in low Klotho rodents. The mechanism is that spironolactone causes downregulation of PiT-1 expression by aldosterone, which inhibits P absorption and suppresses vascular calcification [ 15 , 16 ].…”