1
|
Zhang LF, Hargens AR. Spaceflight-Induced Intracranial Hypertension and Visual Impairment: Pathophysiology and Countermeasures. Physiol Rev 2017; 98:59-87. [PMID: 29167331 DOI: 10.1152/physrev.00017.2016] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 05/25/2017] [Accepted: 05/26/2017] [Indexed: 12/21/2022] Open
Abstract
Visual impairment intracranial pressure (VIIP) syndrome is considered an unexplained major risk for future long-duration spaceflight. NASA recently redefined this syndrome as Spaceflight-Associated Neuro-ocular Syndrome (SANS). Evidence thus reviewed supports that chronic, mildly elevated intracranial pressure (ICP) in space (as opposed to more variable ICP with posture and activity on Earth) is largely accounted for by loss of hydrostatic pressures and altered hemodynamics in the intracranial circulation and the cerebrospinal fluid system. In space, an elevated pressure gradient across the lamina cribrosa, caused by a chronic but mildly elevated ICP, likely elicits adaptations of multiple structures and fluid systems in the eye which manifest themselves as the VIIP syndrome. A chronic mismatch between ICP and intraocular pressure (IOP) in space may acclimate the optic nerve head, lamina cribrosa, and optic nerve subarachnoid space to a condition that is maladaptive to Earth, all contributing to the pathogenesis of space VIIP syndrome. Relevant findings help to evaluate whether artificial gravity is an appropriate countermeasure to prevent this seemingly adverse effect of long-duration spaceflight.
Collapse
Affiliation(s)
- Li-Fan Zhang
- Department of Aerospace Physiology, Fourth Military Medical University, Xi'an, China; and Department of Orthopaedic Surgery, University of California, San Diego, California
| | - Alan R Hargens
- Department of Aerospace Physiology, Fourth Military Medical University, Xi'an, China; and Department of Orthopaedic Surgery, University of California, San Diego, California
| |
Collapse
|
2
|
Zeredo ZL, Toda K, Kumei Y. Neuronal Activity in the Subthalamic Cerebrovasodilator Area under Partial-Gravity Conditions in Rats. Life (Basel) 2014; 4:107-16. [PMID: 25370031 PMCID: PMC4187145 DOI: 10.3390/life4010107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 02/18/2014] [Accepted: 02/26/2014] [Indexed: 01/23/2023] Open
Abstract
The reduced-gravity environment in space is known to cause an upward shift in body fluids and thus require cardiovascular adaptations in astronauts. In this study, we recorded in rats the neuronal activity in the subthalamic cerebrovasodilator area (SVA), a key area that controls cerebral blood flow (CBF), in response to partial gravity. “Partial gravity” is the term that defines the reduced-gravity levels between 1 g (the unit gravity acceleration on Earth) and 0 g (complete weightlessness in space). Neuronal activity was recorded telemetrically through chronically implanted microelectrodes in freely moving rats. Graded levels of partial gravity from 0.4 g to 0.01 g were generated by customized parabolic-flight maneuvers. Electrophysiological signals in each partial-gravity phase were compared to those of the preceding 1 g level-flight. As a result, SVA neuronal activity was significantly inhibited by the partial-gravity levels of 0.15 g and lower, but not by 0.2 g and higher. Gravity levels between 0.2–0.15 g could represent a critical threshold for the inhibition of neurons in the rat SVA. The lunar gravity (0.16 g) might thus trigger neurogenic mechanisms of CBF control. This is the first study to examine brain electrophysiology with partial gravity as an experimental parameter.
Collapse
Affiliation(s)
- Zeredo L Zeredo
- Graduate School, Tokyo Medical and Dental University, Tokyo 113-8549, Japan.
| | - Kazuo Toda
- Graduate School, Nagasaki University, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan.
| | - Yasuhiro Kumei
- Graduate School, Tokyo Medical and Dental University, Tokyo 113-8549, Japan.
| |
Collapse
|
3
|
Kiss JZ. Plant biology in reduced gravity on the Moon and Mars. PLANT BIOLOGY (STUTTGART, GERMANY) 2014; 16 Suppl 1:12-7. [PMID: 23889757 DOI: 10.1111/plb.12031] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Accepted: 02/28/2013] [Indexed: 05/20/2023]
Abstract
While there have been numerous studies on the effects of microgravity on plant biology since the beginning of the Space Age, our knowledge of the effects of reduced gravity (less than the Earth nominal 1 g) on plant physiology and development is very limited. Since international space agencies have cited manned exploration of Moon/Mars as long-term goals, it is important to understand plant biology at the lunar (0.17 g) and Martian levels of gravity (0.38 g), as plants are likely to be part of bioregenerative life-support systems on these missions. First, the methods to obtain microgravity and reduced gravity such as drop towers, parabolic flights, sounding rockets and orbiting spacecraft are reviewed. Studies on gravitaxis and gravitropism in algae have suggested that the threshold level of gravity sensing is around 0.3 g or less. Recent experiments on the International Space Station (ISS) showed attenuation of phototropism in higher plants occurs at levels ranging from 0.l g to 0.3 g. Taken together, these studies suggest that the reduced gravity level on Mars of 0.38 g may be enough so that the gravity level per se would not be a major problem for plant development. Studies that have directly considered the impact of reduced gravity and microgravity on bioregenerative life-support systems have identified important biophysical changes in the reduced gravity environments that impact the design of these systems. The author suggests that the current ISS laboratory facilities with on-board centrifuges should be used as a test bed in which to explore the effects of reduced gravity on plant biology, including those factors that are directly related to developing life-support systems necessary for Moon and Mars exploration.
Collapse
Affiliation(s)
- J Z Kiss
- Department of Biology, University of Mississippi, University, MS, USA
| |
Collapse
|
4
|
Zhang LF. Region-specific vascular remodeling and its prevention by artificial gravity in weightless environment. Eur J Appl Physiol 2013; 113:2873-95. [DOI: 10.1007/s00421-013-2597-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Accepted: 01/20/2013] [Indexed: 10/27/2022]
|
5
|
Kiss JZ, Millar KDL, Edelmann RE. Phototropism of Arabidopsis thaliana in microgravity and fractional gravity on the International Space Station. PLANTA 2012; 236:635-45. [PMID: 22481136 DOI: 10.1007/s00425-012-1633-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 03/22/2012] [Indexed: 05/21/2023]
Abstract
While there is a great deal of knowledge regarding plant growth and development in microgravity aboard orbiting spacecraft, there is little information available about these parameters in reduced or fractional gravity conditions (less than the nominal 1g on Earth). Thus, in these experiments using the European Modular Cultivation System on the International Space Station, we studied the interaction between phototropism and gravitropism in the WT and mutants of phytochrome A and B of Arabidopis thaliana. Fractional gravity and the 1 g control were provided by centrifuges in the spaceflight hardware, and unidirectional red and blue illumination followed a white light growth period in the time line of the space experiments. The existence of red-light-based positive phototropism in hypocotyls of seedlings that is mediated by phytochrome was confirmed in these microgravity experiments. Fractional gravity studies showed an attenuation of red-light-based phototropism in both roots and hypocotyls of seedlings occurring due to gravitational accelerations ranging from 0.l to 0.3 g. In contrast, blue-light negative phototropism in roots, which was enhanced in microgravity compared with the 1g control, showed a significant attenuation at 0.3 g. In addition, our studies suggest that the well-known red-light enhancement of blue-light-induced phototropism in hypocotyls is likely due to an indirect effect by the attenuation of gravitropism. However, red-light enhancement of root blue-light-based phototropism may occur via a more direct effect on the phototropism system itself, most likely through the phytochrome photoreceptors. To our knowledge, these experiments represent the first to examine the behavior of flowering plants in fractional or reduced gravity conditions.
Collapse
Affiliation(s)
- John Z Kiss
- Department of Botany, Miami University, Oxford, OH 45056, USA.
| | | | | |
Collapse
|
6
|
Wagner EB, Granzella NP, Saito H, Newman DJ, Young LR, Bouxsein ML. Partial weight suspension: a novel murine model for investigating adaptation to reduced musculoskeletal loading. J Appl Physiol (1985) 2010; 109:350-7. [PMID: 20522735 DOI: 10.1152/japplphysiol.00014.2009] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We developed a new model of hypodynamic loading to support mice in chronic conditions of partial weight bearing, enabling simulations of reduced gravity environments and related clinical conditions. The novel hardware allows for reduced loading between 10 and 80% of normal body weight on all four limbs and enables characteristic quadrupedal locomotion. Ten-week-old female BALB/cByJ mice were supported for 21 days under Mars-analog suspension (38% weight bearing) and compared with age-matched and jacketed (100% weight bearing) controls. After an initial adaptation, weight gain did not differ between groups, suggesting low levels of animal stress. Relative to age-matched controls, mice exposed to Mars-analog loading had significantly lower muscle mass (-23% gastrocnemius wet mass, P < 0.0001); trabecular and cortical bone morphology (i.e., trabecular bone volume: -24% at the distal femur, and cortical thickness: -11% at the femoral midshaft, both P < 0.001); and biomechanical properties of the femoral midshaft (i.e., -27% ultimate moment, P < 0.001). Bone formation indexes were decreased compared with age-matched full-weight-bearing mice, whereas resorption parameters were largely unchanged. Singly housed, full-weight-bearing controls with forelimb jackets were largely similar to age-matched, group-housed controls, although a few variables differed and warrant further investigation. Altogether, these data provide strong rationale for use of our new model of partial weight bearing to further explore the musculoskeletal response to reduced loading environments.
Collapse
Affiliation(s)
- Erika B Wagner
- Division of Health Science and Technology, Harvard-Massachusetts Institute of Technology, Cambridge, MA, USA.
| | | | | | | | | | | |
Collapse
|
7
|
Lin LJ, Gao F, Bai YG, Bao JX, Huang XF, Ma J, Zhang LF. Contrasting effects of simulated microgravity with and without daily −Gx gravitation on structure and function of cerebral and mesenteric small arteries in rats. J Appl Physiol (1985) 2009; 107:1710-21. [DOI: 10.1152/japplphysiol.00493.2009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study was designed to test the hypothesis that a 28-day tail suspension (SUS) could induce hypertrophy and enhanced myogenic and vasoconstrictor reactivity in middle cerebral arteries (MCAs), whereas atrophy and decreased myogenic and vasoconstrictor responses in mesenteric third-order arterioles (MSAs). Also, in addition to the functional enhancement in MCAs, structural changes in both kinds of arteries and functional decrement in MSAs could all be prevented by the intervention of daily 1-h dorsoventral (−Gx) gravitation by restoring to standing posture. To test this hypothesis, vessel diameters to pressure alterations and nonreceptor- and receptor-mediated agonists were determined using a pressure arteriograph with a procedure to measure in vivo length and decrease hysteresis of vessel segments and longitudinal middlemost sections of vessels fixed at maximally dilated state were examined using electron microscopy and histomorphometry. Functional studies showed that 28-day tail-suspended, head-down tilt (SUS) resulted in enhanced and decreased myogenic tone and vasoconstrictor responses, respectively, in MCAs and MSAs. Histomorphometric data revealed that SUS-induced hypertrophic changes in MCAs characterized by increases in thickness (T) and cross-sectional area (CSA) of the media and the number of vascular smooth-muscle-cell layers (NCL), whereas in MSAs, it induced decreases in medial CSA and T and NCL. Daily 1-h −Gx over 28 days can fully prevent these differential structural changes in both kinds of small arteries and the functional decrement in MSAs, but not the augmented myogenic tone and increased vasoreactivity in the MCAs. These findings have revealed special features of small resistance arteries during adaptation to microgravity with and without gravity-based countermeasure.
Collapse
Affiliation(s)
- Le-Jian Lin
- Department of Aerospace Physiology and Key Laboratory of Aerospace Medicine of Ministry of Education,
| | - Fang Gao
- Department of Aerospace Physiology and Key Laboratory of Aerospace Medicine of Ministry of Education,
| | - Yun-Gang Bai
- Department of Aerospace Physiology and Key Laboratory of Aerospace Medicine of Ministry of Education,
| | - Jun-Xiang Bao
- Department of Aerospace Physiology and Key Laboratory of Aerospace Medicine of Ministry of Education,
| | - Xiao-Feng Huang
- Central Laboratory, School of Basic Medicine, Fourth Military Medical University, Xi'an, China
| | - Jin Ma
- Department of Aerospace Physiology and Key Laboratory of Aerospace Medicine of Ministry of Education,
| | - Li-Fan Zhang
- Department of Aerospace Physiology and Key Laboratory of Aerospace Medicine of Ministry of Education,
| |
Collapse
|
8
|
Gao F, Bao J, Xue J, Huang J, Huang W, Wu S, Zhang LF. Regional specificity of adaptation change in large elastic arteries of simulated microgravity rats. ACTA ACUST UNITED AC 2009; 96:167-87. [DOI: 10.1556/aphysiol.96.2009.2.3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
9
|
de Carvalho LP, Takeshita D, Carillo BA, Lisbôa BCG, Molina G, Beutel A, Yasumura EG, Takiya CM, Valero VB, de Campos, Jr. RR, Dohmann HF, Han SW. Hydrodynamics- and Ultrasound-Based Transfection of Heart with Naked Plasmid DNA. Hum Gene Ther 2007; 18:1233-43. [DOI: 10.1089/hum.2007.063] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Leonardo Pinto de Carvalho
- Interdisciplinary Center for Gene Therapy (CINTERGEN), Federal University of São Paulo, São Paulo-SP, 04044-010, Brazil
- PROCEP, ProCardiaco Hospital, Rio de Janeiro-RJ, 22280-000, Brazil
| | - Daniela Takeshita
- Interdisciplinary Center for Gene Therapy (CINTERGEN), Federal University of São Paulo, São Paulo-SP, 04044-010, Brazil
| | - Bruno A. Carillo
- Department of Physiology, Federal University of São Paulo, São Paulo-SP, 04023-062, Brazil
| | - Bianca Cristina Garcia Lisbôa
- Interdisciplinary Center for Gene Therapy (CINTERGEN), Federal University of São Paulo, São Paulo-SP, 04044-010, Brazil
| | - Gustavo Molina
- Interdisciplinary Center for Gene Therapy (CINTERGEN), Federal University of São Paulo, São Paulo-SP, 04044-010, Brazil
| | - Abram Beutel
- Department of Physiology, Federal University of São Paulo, São Paulo-SP, 04023-062, Brazil
| | - Eduardo Gallatti Yasumura
- Interdisciplinary Center for Gene Therapy (CINTERGEN), Federal University of São Paulo, São Paulo-SP, 04044-010, Brazil
| | - Christina Maeda Takiya
- Department of Histopathology, Federal University of Rio de Janeiro, Rio de Janeiro-RJ, 21949-900, Brazil
| | - Valderez Bastos Valero
- Interdisciplinary Center for Gene Therapy (CINTERGEN), Federal University of São Paulo, São Paulo-SP, 04044-010, Brazil
| | | | | | - Sang Won Han
- Interdisciplinary Center for Gene Therapy (CINTERGEN), Federal University of São Paulo, São Paulo-SP, 04044-010, Brazil
- Department of Biophysics, Federal University of São Paulo, São Paulo-SP, 04023-062, Brazil
| |
Collapse
|
10
|
Gashev AA, Delp MD, Zawieja DC. Inhibition of active lymph pump by simulated microgravity in rats. Am J Physiol Heart Circ Physiol 2006; 290:H2295-308. [PMID: 16399874 DOI: 10.1152/ajpheart.00260.2005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
During spaceflight the normal head-to-foot hydrostatic pressure gradients are eliminated and body fluids shift toward the head, resulting in a diminished fluid volume in the legs and an increased fluid volume in the head, neck, and upper extremities. Lymphatic function is important in the maintenance of normal tissue fluid volume, but it is not clear how microgravity influences lymphatic pumping. We performed a detailed evaluation of the influence of simulated microgravity on lymphatic diameter, wall thickness, elastance, tone, and other measures of phasic contractility in isolated lymphatics. Head-down tail suspension (HDT) rats were used to simulate the effects of microgravity. Animals were exposed to HDT for 2 wk, after which data were collected and compared with the control non-HDT group. Lymphatics from four regional lymphatic beds (thoracic duct, cervical, mesenteric, and femoral lymphatics) were isolated, cannulated, and pressurized. Input and output pressures were adjusted to apply a range of transmural pressures and flows to the lymphatics. Simulated microgravity caused a potent inhibition of pressure/stretch-stimulated pumping in all four groups of lymphatics. The greatest inhibition was found in cervical lymphatics. These findings presumably are correlated to the cephalic fluid shifts that occur in HDT rats as well as those observed during spaceflight. Flow-dependent pump inhibition was increased after HDT, especially in the thoracic duct. Mesenteric lymphatics were less strongly influenced by HDT, which may support the idea that lymph hydrodynamic conditions in the mesenteric lymphatic during HDT are not dramatically altered.
Collapse
Affiliation(s)
- Anatoliy A Gashev
- Department of Medical Physiology, College of Medicine, Cardiovascular Research Institute Division of Lymphatic Biology, Texas A&M University System Health Science Center, 336 Reynolds Medical Bldg., College Station, TX 77843-1114, USA.
| | | | | |
Collapse
|
11
|
Tanaka K, Gotoh TM, Awazu C, Morita H. Roles of the vestibular system in controlling arterial pressure in conscious rats during a short period of microgravity. Neurosci Lett 2006; 397:40-3. [PMID: 16384644 DOI: 10.1016/j.neulet.2005.11.052] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2005] [Revised: 11/27/2005] [Accepted: 11/28/2005] [Indexed: 11/27/2022]
Abstract
In order to evaluate the roles of the vestibular system in controlling arterial pressure (AP) during exposure to a short period of microgravity (microG), the AP was measured in conscious free-moving rats having intact vestibular systems and those having vestibular lesions (FM-Intact and FM-VL groups, respectively). During free drop-induced microG, the AP increased in the FM-Intact group; it was 38+/-4 mmHg more than the AP observed during 1G. However, the increase in AP was significantly lower in the FM-VL group (20+/-2 mmHg). Further, to examine the sudden effect of a body floating in the midair in response to the AP during exposure to muG a body stabilizer was placed on the back of rats having intact vestibular systems and those having vestibular lesions (STAB-Intact and STAB-VL groups, respectively). The increase in the AP was significantly depressed in the STAB-Intact group; when compared with that in the FM-Intact group, but the increase was still significant (27+/-2 mmHg). On the other hand, the increase in the AP was completely eliminated in the STAB-VL group (7+/-5 mmHg). These results indicate that the AP increases during exposure to muG in conscious rats, and the vestibular system and body stability are significantly involved in this response.
Collapse
Affiliation(s)
- Kunihiko Tanaka
- Department of Physiology, Gifu University, Graduate School of Medicine, Gifu 501-1194, Japan.
| | | | | | | |
Collapse
|