Optimization of a Tricalcium Phosphate-Based Bone Model Using Cell-Sheet Technology to Simulate Bone Disorders

Alexandra Damerau,Frank Buttgereit,Timo Gaber

doi:10.3390/pr10030550

Abstract

Bone diseases such as osteoporosis, delayed or impaired bone healing, and osteoarthritis still represent a social, financial, and personal burden for affected patients and society. Fully humanized in vitro 3D models of cancellous bone tissue are needed to develop new treatment strategies and meet patient-specific needs. Here, we demonstrate a successful cell-sheet-based process for optimized mesenchymal stromal cell (MSC) seeding on a β-tricalcium phosphate (TCP) scaffold to generate 3D models of cancellous bone tissue. Therefore, we seeded MSCs onto the β-TCP scaffold, induced osteogenic differentiation, and wrapped a single osteogenically induced MSC sheet around the pre-seeded scaffold. Comparing the wrapped with an unwrapped scaffold, we did not detect any differences in cell viability and structural integrity but a higher cell seeding rate with osteoid-like granular structures, an indicator of enhanced calcification. Finally, gene expression analysis showed a reduction in chondrogenic and adipogenic markers, but an increase in osteogenic markers in MSCs seeded on wrapped scaffolds. We conclude from these data that additional wrapping of pre-seeded scaffolds will provide a local niche that enhances osteogenic differentiation while repressing chondrogenic and adipogenic differentiation. This approach will eventually lead to optimized preclinical in vitro 3D models of cancellous bone tissue to develop new treatment strategies.

Highlights

Received: 4 February 2022Bone defects and healing disorders arise from various causes such as fractures, other traumas, tumors, infections, dental restorations, healing disorders, and congenital malformations
Since it is essential to achieve flexibility in the size of the preclinical in vitro bone model to allow for high throughput, use in a perfused cell culture chamber, or regeneration of different sized bone defects, we investigated the FDA-approved synthetic β-tricalcium phosphate (TCP)-based bone graft substitute (1–2 mm particle size)
mesenchymal stromal cell (MSC) were seeded at a high density onto a temperature-responsive cell culture surface and in parallel on biodegradable β-tricalcium phosphate (β-TCP) scaffolds (Figure 1A)

Summary

Introduction

Bone defects and healing disorders arise from various causes such as fractures, other traumas, tumors, infections, dental restorations, healing disorders, and congenital malformations. They can lead to pain and significant loss of quality of life [1–3]. The prevalence of bone diseases and healing disorders increases with life expectancy [4,5]. Both regenerating bone defects and treating healing disorders represent considerable challenges for clinicians. Over the past two decades, significant progress has been achieved in developing tissue engineering concepts for the production of synthetic bone substitutes that overcome these challenges by adding new possibilities to standard surgical procedures for the treatment of these patients [2,3]

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Conclusion