Solving the insoluble: calciprotein particles mediate bulk mineral transport

Protein mineral complexes, or calciprotein particles, are formed by calcium, phosphate, and the plasma protein fetuin-A. Crystalline calciprotein particles cause soft tissue calcification, oxidative stress, and inflammation, all well-known complications in chronic kidney disease. The T50 calcification propensity test measures how long it takes for amorphous calciprotein particles to crystallize. A study in this volume demonstrates remarkably low calcification propensity in cord blood, despite high mineral concentration. This hints to previously unidentified calcification inhibitors. Protein mineral complexes, or calciprotein particles, are formed by calcium, phosphate, and the plasma protein fetuin-A. Crystalline calciprotein particles cause soft tissue calcification, oxidative stress, and inflammation, all well-known complications in chronic kidney disease. The T50 calcification propensity test measures how long it takes for amorphous calciprotein particles to crystallize. A study in this volume demonstrates remarkably low calcification propensity in cord blood, despite high mineral concentration. This hints to previously unidentified calcification inhibitors. Cord blood effectively resists mineralization through mechanisms that stabilize calciprotein particlesKidney InternationalVol. 103Issue 4PreviewCalcium and phosphate levels in serum are maintained well below the point of spontaneous precipitation yet well above the solubility of bulk bone mineral, readily sustaining crystal growth and ripening once seeded. Despite this metastability, unwanted mineral deposition outside osseous tissue is typically only observed in old age and in certain disease states (e.g., chronic kidney disease). For decades, hyperphosphatemia has been considered a prime driver of ectopic mineralization in chronic kidney disease, yet many other mammalian species have much higher serum phosphate concentrations than human adults without obvious sequelae. Full-Text PDF