A study from several Italian institutions and the ALBA Synchrotron suggest crystalline calcium carbonate as a precursor of hydroxyapatite in the process of bone formation. Since hydroxyapatite is a mineral constituting 70% of the mass of bone, these findings may have potential applications in the development of new therapeutic approaches in bone cancer. Thanks to the MISTRAL beamline at ALBA, researchers were able to create a 3D tomogram of human cells and visualize calcium depositions inside them.
Stem cells are “non-specialized” cells that can differentiate (transform) into a specific type of cell with a specific function. To become bone cells, stem cells need to “learn” how to take calcium to form the bones. This is related to biomineralization, a process by which living organisms produce minerals, often to harden or stiffen existing tissues. Calcium is known to be found in bones in the form of hydroxyapatite, which is a naturally occurring mineral form of calcium apatite and represents approximately 70% of the mass of bones.
In human cells, biomineralization culminates with the formation of hydroxyapatite, but the mechanism that explains the origination inside the cell and the propagation of the mineral in the extracellular matrix remains largely unexplained, and its characterization is highly controversial, especially in humans.
An interdisciplinary research team, formed by several Italian institutions and the ALBA Synchrotron, used synchrotron-based techniques to characterize the contents of calcium depositions in human stem cells induced to differentiate towards bone cells (osteoblasts). They compared the results for cells at 4 and 10 days after the osteoblastic induction.
Rad more on the ALBA website
Image: Model of early phases of biomineralization showing the localization and composition evolution of Ca compounds during the early phases of osteogenic differentiation. The figure reports also the spectra of Calcite and hydroxyapatite.