title: Large artery remodeling and dynamics following simulated microgravity by prolonged head-down tilt bed rest in humans.
abstract: The effects of simulated microgravity on the static and dynamic properties of large arteries are still mostly unknown. The present study evaluated, using an integrated vascular approach, changes in structure and function of the common carotid and femoral arteries (CCA and CFA) after prolonged head-down tilt bed rest (HDTBR). Ten healthy men were enrolled in a 5-week HDTBR study endorsed by the Italian Space Agency (ASI). Arterial geometry, flow, stiffness, and shear rate were evaluated by ultrasound. Local carotid pulse pressure and wave reflection were studied by applanation tonometry. After five weeks of HDTBR, CFA showed a decrease in lumen diameter without significant changes in wall thickness (IMT), resulting in an inward remodeling. Local carotid pulse pressure decreased and carotid-to-brachial pressure amplification increased. The ratio of systolic-to-diastolic volumetric flow in CFA decreased, whereas in CCA it tended to increase. Indices of arterial stiffness and shear rate did not change during HDTBR, either in CCA or CFA. In summary, prolonged HDTBR has a different impact on CCA and CFA structure and flow, probably depending on the characteristics of the vascular bed perfused.
authors: Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, 56124 Pisa, Italy.
authors: Carlo
authors: C
authors: Palombo
authors: Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, 56124 Pisa, Italy.
authors: Carmela
authors: C
authors: Morizzo
authors: Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, 56124 Pisa, Italy.
authors: Martino
authors: M
authors: Baluci
authors: Department of Medical Biotechnologies and Translational Medicine, University of Milan, 20129 Milan, Italy.
authors: Daniela
authors: D
authors: Lucini
authors: Department of Information Engineering, University of Florence, 50139 Florence, Italy.
authors: Stefano
authors: 0000-0002-7410-6057
authors: S
authors: Ricci
authors: Department of Medicine, Surgery and Health Sciences, University of Trieste, 34127 Trieste, Italy.
authors: Gianni
authors: G
authors: Biolo
authors: Department of Information Engineering, University of Florence, 50139 Florence, Italy.
authors: Piero
authors: 0000-0002-7984-3128
authors: P
authors: Tortoli
authors: Department of Surgical, Medical, Molecular and Critical Area Pathology, University of Pisa, 56124 Pisa, Italy.
authors: Michaela
authors: M
authors: Kozakova
mesh_terms: D001510:Bed Rest; D017536:Carotid Artery, Common / Q000502:physiology*; D005263:Femoral Artery / Q000502:physiology*; D018475:Head-Down Tilt; D064368:Healthy Volunteers; D006400:Hematocrit; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D063177:Pulse Wave Analysis; D059289:Vascular Stiffness; D014893:Weightlessness; D018474:Weightlessness Simulation; D055815:Young Adult
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