Bone scaffold architecture modulates the development of mineralized bone matrix by human embryonic stem cells

Abstract

Decellularized bone has been widely used as a scaffold for bone formation, due to its similarity to the native bone matrix and excellent osteoinductive and biomechanical properties. We have previously shown that human mesenchymal and embryonic stem cells form functional bone matrix on such scaffolds, without the use of growth factors. In this study, we focused on differences in bone matrix that exist even among identical harvesting sites, and the effects of the matrix architecture and mineral content on bone formation by human embryonic stem cells (hESC). Mesenchymal progenitors derived from hESCs were cultured for 5 weeks in decellularized bone scaffolds with three different densities: low (0.281 ± 0.018 mg/mm3), medium (0.434 ± 0.015 mg/mm3) and high (0.618 ± 0.027 mg/mm3). The medium-density group yielded highest densities of cells and newly assembled bone matrix, presumably due to the best balance between the transport of nutrients and metabolites to and from the cells, space for cell infiltration, surface for cell attachment and the mechanical strength of the scaffolds, all of which depend on the scaffold density. Bone mineral was beneficial for the higher expression of bone markers in cultured cells and more robust accumulation of the new bone matrix.

Enhanced Differentiation of Human Embryonic Stem Cells on Extracellular Matrix-Containing Osteomimetic Scaffolds for Bone Tissue Engineering

“…A rationale for this work was based on recent studies that demonstrated the potential of decellularized bone matrices in directing the differentiation of hESCs and hMSCs into osteogenic lineage. 55,56 In this study, we used microsphere-sintering to develop scaffolds. This fabrication technique produces scaffolds of tunable porosity and mechanical strength within the range of trabecular bone.…”

“…To date, great strides have been taken in using native bone components to create scaffolds to promote the growth of osteoblast-like cells, however, most approaches focus on one element of the ECM as opposed to the entire network. [55][56][57][58][59][60][61][62][63][64] Decellularized scaffolds composed of the organic and inorganic elements of bone ECM are osteoinductive and osteoconductive. The interactions between cells and the ECM have the ability to define cell development and function.…”

“…This hypothesis is based on studies demonstrating the use of native bone ECM components in stimulating hESCs and hMSCs to differentiate into osteoblasts. 55,56 To this end, the properties of the osteomimetic scaffolds such as ECM composition and morphology and the in vitro differentiation of hESCs into bone tissue were investigated.…”

Mimicking biophysical stimuli within bone tumor microenvironment

“…In the dynamic, unconfined compression experiment conducted in this study, a trabecular bone cylinder (thickness h 0 = 2 mm and radius r 0 = 2 mm) was placed between two frictionless impermeable platens and subjected to a sinusoidal displacement with a magnitude of 0.7% strain and a frequency of 1 Hz. The scaffold was assumed to be linearly elastic [7], with the Young Modulus (50 MPa), density (434 kg/m 3 ) and Poisson ratio (0.3) according to our previously published study [8]. A Quasi-static analysis was performed to solve the time-dependent changes in force and displacement.…”

Cultivation of Human Bone-Like Tissue from Pluripotent Stem Cell-Derived Osteogenic Progenitors in Perfusion Bioreactors

“…For smaller (<1 cm) cylindrical bone constructs, we have defined the influences of initial cell seeding density, fluid perfusion rate, and bone scaffold architecture on in vitro bone development (11–13). …”