Author Information

Is this project an undergraduate, graduate, or faculty project?

Undergraduate

Project Type

individual

Campus

Daytona Beach

Authors' Class Standing

Kevin Kowalski, Junior

Lead Presenter's Name

Kevin Kowalski

Lead Presenter's College

DB College of Engineering

Faculty Mentor Name

Dr. Cassandra Juran

Abstract

Spaceflight investigations have demonstrated that reduction in gravity-induced loading regimes is detrimental to maintenance Earth-normal bone and marrow. Mechanistically, however, there are still gaps in knowledge about how the reduction in gravity influences the different niches within the tissue. For example, cortical bone is a stable semi-solid structure that allows for only minor deformations before failure, while marrow is a viscous hydrogel-like material that can resist significant fluidic and compressive forces. We hypothesize that maintenance of different niches within the bone microenvironment are dependent on different loading regimes, and that the collective impact if gravity-induced loading needs to be considered when designing countermeasures for maintenance of astronaut bone health. This study investigated cellular communication and functional mineralization between osteoblasts and embedded osteocytes within a 3D bio-printed bone matrix under different mechanical loading regimes including control, cyclic stretch, static stretch, dynamic fluid shear, and steady state fluid flow. Our findings detail how mechanical loading influences cell structure, cell-cell networking, cell-cell communication, and cytokine release as well as real time monitoring of the total cellular metabolism and mineralization capacity in each mechanical environment. Preliminary three-dimension osteoblast-osteocyte interaction studies showed connexin-43 (CX-43) presence at cell-cell interfaces is nearly absent in the control mechanical condition and regular at cell-cell interactions in dynamic flow and cyclic stretch. Additionally, Von Kossa mineralization assays show that mineralization occurs more readily and at greater % area coverage with mechanical loading. Control wells show sporadic nodes of mineralization with 32% ± 1.7% mineralized area and 12% continuity. Static cultures show higher continuity with 35% and 61% ± 2.5% mineralized area. Last, dynamic stretch has the highest mineralization and continuity (84.9% ± 7.3% and 88% respectively). These data collectively indicate that the mechanical regime the different niche cells are exposed to directly regulate their function.

Did this research project receive funding support (Spark, SURF, Research Abroad, Student Internal Grants, Collaborative, Climbing, or Ignite Grants) from the Office of Undergraduate Research?

No

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The osteocyte-osteoblast network requires dynamic mechanical loading for key functions

Spaceflight investigations have demonstrated that reduction in gravity-induced loading regimes is detrimental to maintenance Earth-normal bone and marrow. Mechanistically, however, there are still gaps in knowledge about how the reduction in gravity influences the different niches within the tissue. For example, cortical bone is a stable semi-solid structure that allows for only minor deformations before failure, while marrow is a viscous hydrogel-like material that can resist significant fluidic and compressive forces. We hypothesize that maintenance of different niches within the bone microenvironment are dependent on different loading regimes, and that the collective impact if gravity-induced loading needs to be considered when designing countermeasures for maintenance of astronaut bone health. This study investigated cellular communication and functional mineralization between osteoblasts and embedded osteocytes within a 3D bio-printed bone matrix under different mechanical loading regimes including control, cyclic stretch, static stretch, dynamic fluid shear, and steady state fluid flow. Our findings detail how mechanical loading influences cell structure, cell-cell networking, cell-cell communication, and cytokine release as well as real time monitoring of the total cellular metabolism and mineralization capacity in each mechanical environment. Preliminary three-dimension osteoblast-osteocyte interaction studies showed connexin-43 (CX-43) presence at cell-cell interfaces is nearly absent in the control mechanical condition and regular at cell-cell interactions in dynamic flow and cyclic stretch. Additionally, Von Kossa mineralization assays show that mineralization occurs more readily and at greater % area coverage with mechanical loading. Control wells show sporadic nodes of mineralization with 32% ± 1.7% mineralized area and 12% continuity. Static cultures show higher continuity with 35% and 61% ± 2.5% mineralized area. Last, dynamic stretch has the highest mineralization and continuity (84.9% ± 7.3% and 88% respectively). These data collectively indicate that the mechanical regime the different niche cells are exposed to directly regulate their function.

 

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