Fluid flow increases mineralized matrix deposition in 3D perfusion culture of marrow stromal osteoblasts in a dose-dependent manner

TLDR

Bone is a highly structured, mechanically active 3D tissue in which cells dynamically interact with mechanical forces and a continuously changing matrix architecture. The study aimed to examine how varying flow perfusion rates affect marrow stromal osteoblast differentiation, matrix production, and mineralization in 3D scaffolds. Marrow stromal osteoblasts were cultured on 3D scaffolds under perfusion flow at different rates for an extended period to promote differentiation and matrix deposition. Fluid perfusion markedly increased mineralized matrix production, with calcium content rising with flow rate, induced pore‑like tissue modeling, and enhanced cell and matrix distribution, demonstrating that flow drives osteoblast differentiation and phenotypic expression and provides a valuable tool for bone biology and tissue engineering.

Abstract

Bone is a complex highly structured mechanically active 3D tissue composed of cellular and matrix elements. The true biological environment of a bone cell is thus derived from a dynamic interaction between responsively active cells experiencing mechanical forces and a continuously changing 3D matrix architecture. To investigate this phenomenon in vitro , marrow stromal osteoblasts were cultured on 3D scaffolds under flow perfusion with different rates of flow for an extended period to permit osteoblast differentiation and significant matrix production and mineralization. With all flow conditions, mineralized matrix production was dramatically increased over statically cultured constructs with the total calcium content of the cultured scaffolds increasing with increasing flow rate. Flow perfusion induced de novo tissue modeling with the formation of pore-like structures in the scaffolds and enhanced the distribution of cells and matrix throughout the scaffolds. These results represent reporting of the long-term effects of fluid flow on primary differentiating osteoblasts and indicate that fluid flow has far-reaching effects on osteoblast differentiation and phenotypic expression in vitro . Flow perfusion culture permits the generation and study of a 3D, actively modeled, mineralized matrix and can therefore be a valuable tool for both bone biology and tissue engineering.