Modelling large scale artery haemodynamics from the heart to the eye in response to simulated microgravity

Abstract

We investigated variations in haemodynamics in response to simulated microgravity across a semi-subject-specific three-dimensional (3D) continuous arterial network connecting the heart to the eye using computational fluid dynamics (CFD) simulations. Using this model we simulated pulsatile blood flow in an upright Earth gravity case and a simulated microgravity case. Under simulated microgravity, regional time-averaged wall shear stress (TAWSS) increased and oscillatory shear index (OSI) decreased in upper body arteries, whilst the opposite was observed in the lower body. Between cases, uniform changes in TAWSS and OSI were found in the retina across diameters. This work demonstrates that 3D CFD simulations can be performed across continuously connected networks of small and large arteries. Simulated results exhibited similarities to low dimensional spaceflight simulations and measured data—specifically that blood flow and shear stress decrease towards the lower limbs and increase towards the cerebrovasculature and eyes in response to simulated microgravity, relative to an upright position in Earth gravity.

Numerical analysis of blood flow in the abdominal aorta under simulated weightlessness and earth conditions

“…A similar relationship can be observed for the average OSI values, which for the rest are 0.076 for the 1G case and 0.063 for the 0G case. They are comparable to the results obtained by Caddy et al 76 . During moderate exercises, we get 0.013 (1G case) and 0.014 (0G case).…”

“…Microgravity does not radically change OSI distribution at rest or during moderate exercise 76 , 77 . A healthy abdominal aorta is typically indicated by an OSI value of zero, which occurs in the primary oscillating blood flow.…”

Organs in orbit: how tissue chip technology benefits from microgravity, a perspective

“…Vascular damage is another factor of cardiovascular disease that has been observed during zero gravity conditions. To understand these outcomes, large scale artery dynamics were modeled in simulated microgravity, providing key insights on their modified mechanics ( Caddy et al, 2024 ).…”

“…Venous thrombosis ( Auñón-Chancellor et al, 2020 ), anemia, and decreased hemoglobin concentration ( Trudel et al, 2020 ; Nicogossian, 2003 ) have all been observed in astronauts on the ISS. Further haemodynamic studies, such as Caddy et al’s, are necessary to resolve these issues ( Caddy et al, 2024 ).Alternatively, the hemoglobin degradation and hemolysis ( Trudel et al, 2022 ) can be utilized in tissue chips to evaluate mechanisms of hemolysis-causing diseases, such as malaria, or test possible therapies. Anemia also increases the susceptibility to infectious diseases like tuberculosis ( Gelaw et al, 2021 ), providing a more rigorous testing apparatus if implemented.…”