Developmental Cues for Bone Formation from Parathyroid Hormone and Parathyroid Hormone-Related Protein in anEx VivoOrganotypic Culture System of Embryonic Chick Femora

Abstract

Enhancement and application of our understanding of skeletal developmental biology is critical to developing tissue engineering approaches to bone repair. We propose that use of the developing embryonic femur as a model to further understand skeletogenesis, and the effects of key differentiation agents, will aid our understanding of the developing bone niche and inform bone reparation. We have used a three-dimensional organotypic culture system of embryonic chick femora to investigate the effects of two key skeletal differentiation agents, parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP), on bone and cartilage development, using a combination of microcomputed tomography and histological analysis to assess tissue formation and structure, and cellular behavior.Stimulation of embryonic day 11 (E11) organotypic femur cultures with PTH and PTHrP initiated osteogenesis. Bone formation was enhanced, with increased collagen I and STRO-1 expression, and cartilage was reduced, with decreased chondrocyte proliferation, collagen II expression, and glycosaminoglycan levels.This study demonstrates the successful use of organotypic chick femur cultures as a model for bone development, evidenced by the ability of exogenous bioactive molecules to differentially modulate bone and cartilage formation. The organotypic model outlined provides a tool for analyzing key temporal stages of bone and cartilage development, providing a paradigm for translation of bone development to improve scaffolds and skeletal stem cell treatments for skeletal regenerative medicine.

Tissue engineered bone using select growth factors: A comprehensive review of animal studies and clinical translation studies in man

“…The authors envisage coordinated spatiotemporal release of select growth factors recapitulating in vivo signalling cascades leading to bone tissue formation. The importance of understanding the developmental processes underpinning bone tissue formation, and their importance in contextualising signalling cascades and the growth factors involved in regenerative medicine is gaining prominence, as understanding these processes is vital to informed clinical bone therapies (Smith et al, 2013;Turner et al, 2013). The data presented here demonstrate the complex and convoluted interplay between administered growth factors with variable success for bone tissue formation dependent on species, dosage and combination.…”

“…For example, the chick model provides an ideal system for investigating bone development biology (Smith et al, 2013). Organotypic culture of embryonic chick femora ex vivo enables investigation and elucidation of processes involved in skeletal development and bone repair Smith et al, 2014a;Smith et al, 2014b;Smith et al, 2012).…”

Remotely Activated Mechanotransduction via Magnetic Nanoparticles Promotes Mineralization Synergistically With Bone Morphogenetic Protein 2: Applications for Injectable Cell Therapy

“…In all MSC‐based strategies for tissue engineering, native endogenous growth factors in wound sites are crucial for orchestrating cell‐mediated tissue regeneration [2, 3, 14, 15, 19]. As a deliverable growth factor, BMP2 is used in clinical applications in which substantial bone apposition is required, such as spinal fusion and treatment of nonunion [29].…”

Alginate-nanohydroxyapatite hydrogel system: Optimizing the formulation for enhanced bone regeneration

“…Samples were dehydrated through a series of graded alcohols, cleared in Histoclear® and embedded in paraffin. Tissue sections 6 μm thick were cut from across the femur samples and stained with Alcian blue/Sirius red (AB/SR), Masson's trichrome or von Kossa staining, as previously described [27]. Images were captured with an Olympus BX-51/22 dotSlide digital virtual microscope and created using OlyVIA 2.1 software (Olympus Soft Imaging Solutions, GmBH).…”