COMMERCIAL BIOMEDICAL TESTING MODULE-3: STS- 135 SPACEFLIGHT’S AFFECTS ON VASCULAR
ATROPHY IN THE HIND LIMBS OF MICE (CBTM-3-VASCULAR ATROPHY)
Research Area: Animal Biology – Vertebrates
Expedition(s): 27 and 28
Principal Investigator(s): ● Ron Midura, PhD, Cleveland Clinic Foundation, Cleveland,
Ohio
RESEARCH OBJECTIVES
Commercial Biomedical Testing Module-3: STS-135 spaceflight's effects on vascular atrophy in
the hind limbs of mice (CBTM-3-Vascular Atrophy) examines the effects of spaceflight on the
skeletal bones of mice and the efficacy of a novel agent that may mitigate the loss of bone
associated with spaceflight. Humans and animals have been observed to lose bone mass during
the reduced gravity of spaceflight. CBTM-3-Vascular Atrophy specifically determines if there
is a correlation between spaceflight induced altered blood supply to the bones and surrounding
tissues with a resultant loss of bone mass.
EARTH BENEFITS
As noted in the preceding paragraph, if a correlation is found between blood supply to bone
and bone mass regulation, new insights into the mechanisms governing how the body responds
to skeletal unloading can likely result. These insights might lead not only to new therapies for
maintaining a healthy musculoskeletal system during long-duration spaceflights but also new
therapies for treating muscle and bone wasting diseases on the Earth.
SPACE BENEFITS
If a correlation is found between blood supply to bone and bone mass regulation, new insights
into the mechanisms governing how the body responds to skeletal unloading can result. Such
insights may lead to new therapies for maintaining a healthy musculoskeletal system during
long-duration spaceflights.
RESULTS
Ground-based studies in rats subjected to chronic head-down tail suspension have been
conducted to simulate the fluid shift towards the head and general cardiovascular
deconditioning that occurs with spaceflight. The purpose of this study was to test the
hypothesis, derived from the results of the aforementioned experiments, that 13 days of
spaceflight aboard the STS-135 mission would enhance narrowing of the blood vessels, increase
the thickness of the innermost layers of the arterial wall, and elicit no change in the mechanical
properties of mouse cerebral arteries (Taylor 2013).
Contrary to the hypothesis, the results showed that myogenic vasoconstriction was less in
cerebral arteries from spaceflight mice, passive pressure-diameter response indicated greater
ability for vascular expansion and contraction and mechanical testing revealed that the arteries
from spaceflight animals had lower effective elastic modulus (tendency to be deformed when
force is applied) and stiffness. Gross structural measurements demonstrated that maximal
diameter was greater in spaceflight mice, while medial wall thickness of cerebral arteries was