Changes in interstitial fluid flow, mass transport and the bone cell response in microgravity and normogravity

Abstract

In recent years, our scientific interest in spaceflight has grown exponentially and resulted in a thriving area of research, with hundreds of astronauts spending months of their time in space. A recent shift toward pursuing territories farther afield, aiming at near-Earth asteroids, the Moon, and Mars combined with the anticipated availability of commercial flights to space in the near future, warrants continued understanding of the human physiological processes and response mechanisms when in this extreme environment. Acute skeletal loss, more severe than any bone loss seen on Earth, has significant implications for deep space exploration, and it remains elusive as to why there is such a magnitude of difference between bone loss on Earth and loss in microgravity. The removal of gravity eliminates a critical primary mechano-stimulus, and when combined with exposure to both galactic and solar cosmic radiation, healthy human tissue function can be negatively affected. An additional effect found in microgravity, and one with limited insight, involves changes in dynamic fluid flow. Fluids provide the most fundamental way to transport chemical and biochemical elements within our bodies and apply an essential mechano-stimulus to cells. Furthermore, the cell cytoplasm is not a simple liquid, and fluid transport phenomena together with viscoelastic deformation of the cytoskeleton play key roles in cell function. In microgravity, flow behavior changes drastically, and the impact on cells within the porous system of bone and the influence of an expanding level of adiposity are not well understood. This review explores the role of interstitial fluid motion and solute transport in porous bone under two different conditions: normogravity and microgravity.

Orthopedic Scaffolds: Evaluation of Structural Strength and Permeability of Fluid Flow via an Open Cell Neovius Structure for Bone Tissue Engineering

“…This fluid flow generates a force on the surface of the implant, which is known as wall shear stress. Studies have shown that the magnitude and pattern of wall shear stress can affect the behavior of cells that come into contact with the implant surface . In areas of high shear stress, cells may align themselves along the direction of fluid flow and experience increased rates of proliferation and migration .…”

“…Studies have shown that the magnitude and pattern of wall shear stress can affect the behavior of cells that come into contact with the implant surface. 32 In areas of high shear stress, cells may align themselves along the direction of fluid flow and experience increased rates of proliferation and migration. 8 Conversely, in areas of low shear stress, cells may become more round and exhibit reduced growth rates.…”

Bioprinting of Cardiac Tissue in Space: Where Are We?

“…The reduced fluid convection rates and slower solute diffusion in microgravity could also lead to impaired heat and biomolecule exchange, potentially favoring the transport of smaller solutes. [ 70 ] Consequently, the integration of 3D bioprinted constructs into a fluidic system that drives convective flow would help to obtain the physiologically relevant environment that is needed for tissue maturation and survival.…”

The potential role of mechanotransduction in the management of pediatric calvarial bone flap repair

“…In particular, biomimetic microarchitectures can be easily imprinted or molded, and hydrogel mechanical properties can be modulated by adjusting the material concentration and crosslinking density to emulate the corresponding properties of precalcified bone (Al Hosni et al, 2022;Mao et al, 2016;Ventre & Netti, 2016). Xia et al (2022) (Grimm et al, 2016), but conversely, bone deterioration and calcium loss occurs in microgravity in the absence of constant loading (Wei et al, 2022). Loading also causes fluid movement within the canalicular system, which exerts fluid shear stress on susceptible surface molecules and cytoskeletal structures protruding from osteocytes and osteoblasts (Owan et al, 1997;Wilmoth et al, 2020).…”