Is there a role in acute kidney injury for FGF23 and Klotho?

Cardio-renal syndrome is a clinical condition that has recently been well defined. In acute kidney disease, this interaction might trigger chronic processes determining the onset of cardiovascular events and the progression of chronic kidney disease. Moreover, the high mortality rate of acute kidney injury (AKI) is also linked to the fact that this condition is often complicated by dysfunctions of other organs such as lungs or heart, or is associated with septic episodes. In this context the role and the potential link between bone, heart and kidney is becoming an important topic of research. The aim of this review is to describe the cardiac alterations in the presence of AKI (cardiorenal syndrome type 3) and explore how bone can interact with heart and kidney in determining and influencing the trend of AKI in the short and long term. The main anomalies of mineral metabolism in patients with AKI will be reported, with specific reference to the alterations of fibroblast growth factor 23 and Klotho as a link between the bone-kidney-heart axis.Lay Summary In this review the cardiac involvement and the interaction between bone, heart and kidney in the presence of acute kidney injury (AKI) are reported. This is a "hot topic" in nephrology research. In fact some evidence demonstrates a potential role for fibroblast growth factor 23, produced in the bone, and Klotho in modulating the inflammation, in endothelial dysfunction and in promoting cardiovascular risk in AKI settings. We think that this review underlines this relationship in a simple way, opening up future research.