Remodeling of tissue-engineered bone structures in vivo

Abstract

Implant design for bone regeneration is expected to be optimized when implant structures resemble the anatomical situation of the defect site. We tested the validity of this hypothesis by exploring the feasibility of generating different in vitro engineered bone-like structures originating from porous silk fibroin scaffolds decorated with RGD sequences (SF-RGD), seeded with human mesenchymal stem cells (hMSC). Scaffolds with small (106 – 212 μm), medium (212 – 300 μm) and large pore diameter ranges (300 – 425 μm) were seeded with hMSC and subsequently differentiated in vitro into bone-like tissue resembling initial scaffold geometries and featuring bone-like structures. Eight weeks after implantation into calvarial defects in mice, the in vitro engineered bone-like tissues had remodeled into bone featuring different proportions of woven/lamellar bone bridging the defects. Regardless of pore diameter all implants integrated well, vascularization was advanced and, bone marrow ingrowth had started. Ultimately, in this defect model, the geometry of the in vitro generated tissue-engineered bone structure, trabecular- or plate-like, had no significant impact on the healing of the defect, owing to an efficient remodeling of its structure after implantation.

In vivo bioresponses to silk proteins

“…The ability of blood vessels to grow within silk scaffolds depends significantly on the silk processing method and scaffold properties such as pore size and pore interconnectivity (31, 63). Blood vessels are physically able to grow into silk scaffolds implanted in vivo but generally require biological signals to invade beyond the surface and into the bulk of the scaffold.…”

Biomaterials in Preclinical Approaches for Engineering Skeletal Tissues

“…The potential of porous silk fibroin scaffolds with RGD sequences [64] was explored by Hofmann et al in calvarian nonloading defects induced in a mouse model. The potential of porous silk fibroin scaffolds with RGD sequences [64] was explored by Hofmann et al in calvarian nonloading defects induced in a mouse model.…”

From silk spinning in insects and spiders to advanced silk fibroin drug delivery systems

“…One colorful description was that these threads could be extended up to a length of 80 km before these would break under their own weight [11]. The mechanical properties of processed silk differ from the native fibers [12][13][14] and are variable upon different treatment [15], but still make it an attractive material for musculoskeletal use and tissue engineering [16][17][18][19][20][21][22]. In contrast to manufacturing conditions of synthetic polymers, the natural process leading to silk is confined to physiologic conditions, i.e.…”