Serum fetuin‐ A concentration and fetuin‐ A ‐containing calciprotein particles in patients with chronic inflammatory disease and renal failure

Aim Fetuin‐ A ( F et‐ A ) is an important regulator of extracellular matrix mineralization. F et‐ A plays a critical role in the formation and stabilization of high molecular weight colloidal protein–mineral complexes known as calciprotein particles ( CPP ). The aim of this study was to examine the effects of inflammation, renal function and dialysis modality on serum F et‐ A and CPP . Methods This is an observational study of patients with chronic kidney disease ( CKD ) and those with chronic inflammatory disease ( CID ) but normal renal function. Serum CPP were quantified indirectly by analysing the apparent reduction in serum F et‐ A concentration (reduction ratio, RR ) after high‐speed centrifugation. Results Serum total F et‐ A concentrations are reduced in renal disease and in patients with CID . CPP were not detectable in the serum of normal individuals. CPP represent an increasing percentage of total circulating F et‐ A concentrations in patients with CID ( RR , 13.3 ± 8.5%), as well as in patients with pre‐dialysis CKD (12.4 ± 7.3%) and those undergoing peritoneal dialysis ( RR , 22.8 ± 6.0%) or haemodialysis ( RR , 38.1 ± 12.8%). The highest F et‐ A RR were found in patients with calcific uraemic arteriolopathy ( CUA ) on haemodialysis (73.9 ± 15.6%). Serum total F et‐ A concentrations and F et‐ A reduction ratios decreased during a single haemodialysis session, by 24% ( P  < 0.001) and 34% ( P  < 0.001), respectively. Conclusion Inflammation appears to be associated with mineral stress even in the absence of renal dysfunction. Patients with CUA on haemodialysis have very high serum F et‐ A reduction ratios, suggesting that this measurement may have a prognostic/diagnostic role in this condition.