Differences in morphogenesis of 3D cultured primary human osteoblasts under static and microfluidic growth conditions.
As information on osteoblast mechanosensitivity response to biomechanical cues in three-dimensional (3D) in vitro microenvironments is sparse, the present study compared morphogenesis of primary human alveolar bone osteoblasts (PHABO) under microchip-based 3D-static conditions, and 3D-fluid flow-mediated biomechanical stimulation in perfusion bioreactors. Discrimination of the respective microenvironment by differential morphogenesis was evident from fluid flow-induced PHABO reorganization into rotund bony microtissue, comprising more densely packed multicellular 3D-aggregates, while viability of microtissues was flow rate dependent. Time-lapse microscopy and simple modeling of biomechanical conditions revealed that physiologically relevant fluid flow-mediated PHABO stimulation was associated with formation of mulberry-like PHABO aggregates within the first 24 h. Differential extracellular matrix deposition patterns and gene expression modulation in PHABO aggregates at day 7 further indicates progressive osteoblast differentiation exclusively in perfusion culture-developed bony microtissues. The results of our study strongly suggest PHABO morphogenesis as discriminator of microenvironmental growth conditions, which in case of the microfluidic 3D microchip-bioreactor are substantiated by triggering in vitro bone microtissue formation concomitant with progressive osteoblastic differentiation. Such microtissue outcomes provide unique insight for mechanobiological studies in response to biomechanical fluid flow cues, and clinically appear promising for in vitro PHABO preconditioning, enabling innovative bone augmentation procedures.
Department of Prosthodontics, Dental School and Hospital, University Medical Center Freiburg, Hugstetter Straße 55, 79106 Freiburg, Germany. Electronic address: brigitte.altmann@uniklinik-freiburg.de.
Brigitte
B
Altmann
Department of Oral Biotechnology, Dental School and Hospital, University Medical Center Freiburg, Hugstetter Straße 55, 79106 Freiburg, Germany.
Anne
A
Löchner
Department of Prosthodontics, Dental School and Hospital, University Medical Center Freiburg, Hugstetter Straße 55, 79106 Freiburg, Germany.
Michael
M
Swain
Department of Prosthodontics, Dental School and Hospital, University Medical Center Freiburg, Hugstetter Straße 55, 79106 Freiburg, Germany.
Ralf-Joachim
RJ
Kohal
Institute for Biological Interfaces-1, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany.
Stefan
S
Giselbrecht
Institute for Biological Interfaces-1, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany.
Eric
E
Gottwald
Department of Oral Biotechnology, Dental School and Hospital, University Medical Center Freiburg, Hugstetter Straße 55, 79106 Freiburg, Germany.
Thorsten
T
Steinberg
Department of Oral Biotechnology, Dental School and Hospital, University Medical Center Freiburg, Hugstetter Straße 55, 79106 Freiburg, Germany.
Pascal
P
Tomakidi
D019149:Bioreactors; D002478:Cells, Cultured; D060833:Cellular Microenvironment; D015870:Gene Expression; D006801:Humans; D044085:Microfluidics; D008855:Microscopy, Electron, Scanning; D009024:Morphogenesis; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism
3D in vitro cell culture; Biomechanical response; Bone microtissue; Osteoblast; Perfusion bioreactor