Fibrous tissues growth and remodeling: Evolutionary micro-mechanical theory

• Published in: Journal of the mechanics and physics of solids 2017-10, Vol.107, p.115-144
• Main Author: Lanir, Yoram
• Format: Article
• Language: English
• Subjects: Biological evolution; Composite materials; Constituents; Growth and remodeling; Living fibrous tissues; Mechanical properties; Mechanistic modeling; Microstructure; Multiscale analysis; Particulate composites; Strain; Tissues
• ISSN: 0022-5096; 1873-4782
• DOI: 10.1016/j.jmps.2017.06.011

•A 3D multiscale mechanistic structural theory for tissue growth and remodeling (G&R) was developed.•The model links the evolution of structure and mechanics with underlying local biological events.•This approach circumvents a basic obstacle in modeling growth due to its non-bijective motion.•Predictions yielded close similarity to structural and mechanical features of evolved tissues.•The results suggest that these important structural and functional features of living tissue evolve with growth. Living fibrous tissues are composite materials having the unique ability to adapt their size, shape, structure and mechanical properties in response to external loading. This adaptation, termed growth and remodeling (G&R), occurs throughout life and is achieved via cell-induced turnover of tissue constituents where some are degraded and new ones are produced. Realistic mathematical modeling of G&R provides insight into the basic processes, allows for hypotheses testing, and constitutes an essential tool for establishing clinical thresholds of pathological remodeling and for the production of tissue substitutes aimed to achieve target structure and properties. In this study, a general 3D micro-mechanical multi-scale theory of G&R in fibrous tissue was developed which connects between the evolution of the tissue structure and properties, and the underlying mechano-biological turnover events of its constituents. This structural approach circumvents a fundamental obstacle in modeling growth mechanics since the growth motion is not bijective. The model was realized for a flat tissue under two biaxial external loadings using data-based parameter values. The predictions show close similarity to characteristics of remodeled adult tissue including its structure, anisotropic and non-linear mechanical properties, and the onset of in situ pre-strain and pre-stress. The results suggest that these important features of living fibrous tissues evolve as they grow.