Human adipose-derived mesenchymal stem cells seeded into a collagen-hydroxyapatite scaffold promote bone augmentation after implantation in the mouse

Abstract

Traumatic injury or surgical excision of diseased bone tissue usually require the reconstruction of large bone defects unable to heal spontaneously, especially in older individuals. This is a big challenge requiring the development of biomaterials mimicking the bone structure and capable of inducing the right commitment of cells seeded within the scaffold. In particular, given their properties and large availability, the human adipose-derived stem cells are considered as the better candidate for autologous cell transplantation. In order to evaluate the regenerative potential of these cells along with an osteoinductive biomaterial, we have used collagen/hydroxyapatite scaffolds to test ectopic bone formation after subcutaneous implantation in mice. The process was analysed both in vivo, by Fluorescent Molecular Tomography (FMT), and ex vivo, to evaluate the formation of bone and vascular structures. The results have shown that the biomaterial could itself be able of promoting differentiation of host cells and bone formation, probably by means of its intrinsic chemical and structural properties, namely the microenvironment. However, when charged with human mesenchymal stem cells, the ectopic bone formation within the scaffold was increased. We believe that these results represent an important advancement in the field of bone physiology, as well as in regenerative medicine.

Mesenchymal Stromal Cell-Seeded Biomimetic Scaffolds as a Factory of Soluble RANKL in Rankl-Deficient Osteopetrosis

“…In fact, previous studies [2,13,35] and the present work demonstrated that this kind of scaffold was bioactive, biodegradable, biocompatible, and easily recognized by cells, thanks to the high hydrophilicity and porosity, particularly in terms of macropores, which fostered cell adhesion, colonization, proliferation, and RANKL cytokine production, in agreement with reports in literature referring to different contexts [36,37]. Moreover, once implanted subcutaneously in mice, these scaffolds were extensively vascularized; in line with other findings [38,39], this should have favored graft-host interaction and MSCs survival, and supported the systemic distribution of soluble factors, likely comprising also RANKL, produced by the implanted cells.…”

In Vivo Evaluation of Biocompatibility and Chondrogenic Potential of a Cell-Free Collagen-Based Scaffold

“…All efforts were made to minimize the number of animals used and their suffering. Pre- and post-grafting procedures were performed as explained previously (Calabrese et al, 2016b , 2017b ). Briefly, surgical procedures were performed under aseptic conditions, with the animals under gas anesthesia (isoflurane).…”

Innovative Biomaterials for Tissue Engineering

“…Calabrese et al in their studies tested a composite bi-layer type-1 collagen-HA/Mg scaffold for osteochondral regeneration, both in vitro and in vivo. They showed that the combination of this scaffold with mesenchymal stem cells (MSC) derived from adipose tissue (hAD-SCs) in the presence of specific differentiation conditions induce osteochondro differentiation both in vitro and in vivo [19][20][21][22][23].…”

“…Also, our group tested in vitro and in vivo potential of collagen type-1/Ha-Mg combination to promote bone injury healing. We demonstrated that although biomimetic scaffolds are "per sè" able to promote tissue regeneration thanks to their high osteoinductivity, their combination with progenitor cells and growth factors would be more efficient [19][20][21]. Generally, osteogenic cells such as adult stem cells (ASC) isolated from adult tissues like bone marrow, adipose tissue, or muscle are good candidate to be transplanted in skeletal lesion together with an appropriate scaffold.…”