Peripheral Arterial and Venous Response to Tilt Test after a 60-Day Bedrest with and without Countermeasures (ES-IBREP)

Abstract

We quantified the impact of 60-day head-down bed rest (HDBR) with countermeasures on arterial and venous response to tilt. Methods: Twenty-one males: 7 control (Con), 7 resistive vibration exercise (RVE) and 7 Chinese herb (Herb) were assessed. Subjects were identified as finisher (F) or non-finishers (NF) at the post-HDBR 20-min tilt test. The cerebral (MCA), femoral (FEM) arterial flow velocity and leg vascular resistance (FRI), the portal vein section (PV), the flow redistribution ratios (MCA/FEM; MCA/PV), the tibial (Tib), gastrocnemius (Gast), and saphenous (Saph) vein sections were measured by echography and Doppler ultrasonography. Arterial and venous parameters were measured at 3-min pre-tilt in the supine position, and at 1 min before the end of the tilt. Results: At post-HDBR tilt, MCA decreased more compared with pre-HDBR tilt in the Con, RVE, and Herb groups, the MCA/FEM tended to decrease in the Con and Herb groups (not significant) but remained stable in the RVE gr. FRI dropped in the Con gr, but remained stable in the Herb gr and increased in the RVE gr. PV decreased less in the Con and Herb groups but remained unchanged in the RVE gr. MCA/PV decreased in the Con and Herb groups, but increased to a similar extent in the RVE gr. Gast section significantly increased more in the Con gr only, whereas Tib section increased more in the Con and Herb groups but not in the RVE gr. The percent change in Saph section was similar at pre- and post-HDBR tilt. Conclusion: In the Con gr, vasoconstriction was reduced in leg and splanchnic areas. RVE and Herb contributed to prevent the loss of vasoconstriction in both areas, but the effect of RVE was higher. RVE and Herb contributed to limit Gast distension whereas only RVE had a protective effect on the Tib.

Vascular and Microvascular Dysfunction Induced by Microgravity and Its Analogs in Humans: Mechanisms and Countermeasures

“…Chinese herbal medicine countermeasures against vascular deconditioning are attractive due to their pleiotropic effects that are not limited to a single mechanism or a single application point ( Lu et al, 2004 ). In 60-day HDBR, TaikongYangxin (“outer space heart-nourishing”), a herbal formula created by the Chinese space agency to boost the physical conditions of astronauts and improve their adaptability in an extreme environment, contributes to the prevention of post-bedrest loss of vasoconstriction in leg and splanchnic areas ( Yuan et al, 2012 ), improves microvascular endothelial function (decrease in plateau vasodilative response to ACh from 46 to 31% of maximal vasodilation to heating, induced by 60-day HDBR, was completely prevented) and preserves endothelial integrity (increase in “apoptotic” EMPs induced by 60-day HDBR was prevented) ( Yuan et al, 2015 ). This herbal extract is composed of over 10 ingredients including Panax ginseng, Astragalus membranaceus, Ligusticum wallichii, Schisandra chinensis, Ophiopogon japonicas, Rehmania glutinosa, Drynaria fortunei, and Poria cocos.…”