FGF23 and chronic kidney disease: Moreover, Peiskerova and coworkers have demonstrated that levels of MMP-2 were significantly higher in CKD patients Stage III–V as compared to those with Stage I–II, and correlated with fibroblast growth factor 23 (FGF-23) and levels of serum phosphate, two important surrogates of oxidative stress and CV risk in these patients [52,71].