0
selected
-
1.
The Effect of Space Travel on Bone Metabolism: Considerations on Today's Major Challenges and Advances in Pharmacology.
Genah, S, Monici, M, Morbidelli, L
International journal of molecular sciences. 2021;(9)
Abstract
Microgravity-induced bone loss is currently a significant and unresolved health risk for space travelers, as it raises the likelihood for irreversible changes that weaken skeletal integrity and the incremental onset of fracture injuries and renal stone formation. Another issue related to bone tissue homeostasis in microgravity is its capacity to regenerate following fractures due to weakening of the tissue and accidental events during the accomplishment of particularly dangerous tasks. Today, several pharmacological and non-pharmacological countermeasures to this problem have been proposed, including physical exercise, diet supplements and administration of antiresorptive or anabolic drugs. However, each class of pharmacological agents presents several limitations as their prolonged and repeated employment is not exempt from the onset of serious side effects, which limit their use within a well-defined range of time. In this review, we will focus on the various countermeasures currently in place or proposed to address bone loss in conditions of microgravity, analyzing in detail the advantages and disadvantages of each option from a pharmacological point of view. Finally, we take stock of the situation in the currently available literature concerning bone loss and fracture healing processes. We try to understand which are the critical points and challenges that need to be addressed to reach innovative and targeted therapies to be used both in space missions and on Earth.
-
2.
Effectiveness of nutritional countermeasures in microgravity and its ground-based analogues to ameliorate musculoskeletal and cardiopulmonary deconditioning-A Systematic Review.
Sandal, PH, Kim, D, Fiebig, L, Winnard, A, Caplan, N, Green, DA, Weber, T
PloS one. 2020;(6):e0234412
Abstract
A systematic review was performed to evaluate the effectiveness of nutrition as a standalone countermeasure to ameliorate the physiological adaptations of the musculoskeletal and cardiopulmonary systems associated with prolonged exposure to microgravity. A search strategy was developed to find all astronaut or human space flight bed rest simulation studies that compared individual nutritional countermeasures with non-intervention control groups. This systematic review followed the guidelines of the Cochrane Handbook for Systematic Reviews and tools created by the Aerospace Medicine Systematic Review Group for data extraction, quality assessment of studies and effect size. To ensure adequate reporting this systematic review followed the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analyses. A structured search was performed to screen for relevant articles. The initial search yielded 4031 studies of which 10 studies were eligible for final inclusion. Overall, the effect of nutritional countermeasure interventions on the investigated outcomes revealed that only one outcome was in favor of the intervention group, whereas six outcomes were in favor of the control group, and 43 outcomes showed no meaningful effect of nutritional countermeasure interventions at all. The main findings of this study were: (1) the heterogeneity of reported outcomes across studies, (2) the inconsistency of the methodology of the included studies (3) an absence of meaningful effects of standalone nutritional countermeasure interventions on musculoskeletal and cardiovascular outcomes, with a tendency towards detrimental effects on specific muscle outcomes associated with power in the lower extremities. This systematic review highlights the limited amount of studies investigating the effect of nutrition as a standalone countermeasure on operationally relevant outcome parameters. Therefore, based on the data available from the included studies in this systematic review, it cannot be expected that nutrition alone will be effective in maintaining musculoskeletal and cardiopulmonary integrity during space flight and bed rest.
-
3.
Heart in space: effect of the extraterrestrial environment on the cardiovascular system.
Hughson, RL, Helm, A, Durante, M
Nature reviews. Cardiology. 2018;(3):167-180
Abstract
National space agencies and private corporations aim at an extended presence of humans in space in the medium to long term. Together with currently suboptimal technology, microgravity and cosmic rays raise health concerns about deep-space exploration missions. Both of these physical factors affect the cardiovascular system, whose gravity-dependence is pronounced. Heart and vascular function are, therefore, susceptible to substantial changes in weightlessness. The altered cardiovascular function in space causes physiological problems in the postflight period. A compromised cardiovascular system can be excessively vulnerable to space radiation, synergistically resulting in increased damage. The space radiation dose is significantly lower than in patients undergoing radiotherapy, in whom cardiac damage is well-documented following cancer therapy in the thoracic region. Nevertheless, epidemiological findings suggest an increased risk of late cardiovascular disease even with low doses of radiation. Moreover, the peculiar biological effectiveness of heavy ions in cosmic rays might increase this risk substantially. However, whether radiation-induced cardiovascular effects have a threshold at low doses is still unclear. The main countermeasures to mitigate the effect of the space environment on cardiac function are physical exercise, antioxidants, nutraceuticals, and radiation shielding.
-
4.
Coronary artery disease and lunar catecholamine cardiomyopathy.
Rowe, WJ
International journal of cardiology. 2017;:42-46
Abstract
Show how lunar catecholamine cardiomyopathy alone, exemplified by Neil Armstrong's single space walk, prior to exposure to inhalation of fine particulate matter, can trigger " Neil Armstrong Syndrome" or by Irwin with coronary, possibly hypertensive heart disease, and catecholamine cardiomyopathy. With space flight, invariably magnesium ion deficits, catecholamine elevations, vicious cycles. Design Use lunar heart rates while configuring rover to show severe tachycardia component of the syndrome. Use Irwin's stress test-" cyanotic fingernails" to support Apollo 15 Space Syndrome. Use Irwin's autobiography to compensate for often incomplete data. Results Paper shows that both Irwin as well as Armstrong meet criteria of my 2nd. Space Syndrome: severe thirst, severe shortness of breath, severe tachycardia, the latter, corrected by replenishing plasma volume. Conclusions Irwin, with a history of hypertension prior to the Apollo 15 mission and classical angina during Earth reentry, may have had coronary as well as hypertensive heart disease whereas there was no evidence that Armstrong had these conditions prior or during his mission. However both, on return to Earth, had abnormal stress tests.
-
5.
Dysbiosis and Immune Dysregulation in Outer Space.
Cervantes, JL, Hong, BY
International reviews of immunology. 2016;(1):67-82
Abstract
In space, the lifestyle, relative sterility of spaceship and extreme environmental stresses, such as microgravity and cosmic radiation, can compromise the balance between human body and human microbiome. An astronaut's body during spaceflight encounters increased risk for microbial infections and conditions because of immune dysregulation and altered microbiome, i.e. dysbiosis. This risk is further heightened by increase in virulence of pathogens in microgravity. Health status of astronauts might potentially benefit from maintaining a healthy microbiome by specifically managing their diet on space in addition to probiotic therapies. This review focuses on the current knowledge/understanding of how spaceflight affects human immunity and microbiome.
-
6.
Effects of sex and gender on adaptation to space: musculoskeletal health.
Ploutz-Snyder, L, Bloomfield, S, Smith, SM, Hunter, SK, Templeton, K, Bemben, D
Journal of women's health (2002). 2014;(11):963-6
-
-
Free full text
-
Abstract
There is considerable variability among individuals in musculoskeletal response to long-duration spaceflight. The specific origin of the individual variability is unknown but is almost certainly influenced by the details of other mission conditions such as individual differences in exercise countermeasures, particularly intensity of exercise, dietary intake, medication use, stress, sleep, psychological profiles, and actual mission task demands. In addition to variations in mission conditions, genetic differences may account for some aspect of individual variability. Generally, this individual variability exceeds the variability between sexes that adds to the complexity of understanding sex differences alone. Research specifically related to sex differences of the musculoskeletal system during unloading is presented and discussed.
-
7.
Separate and combined effects of 21-day bed rest and hypoxic confinement on body composition.
Debevec, T, Bali, TC, Simpson, EJ, Macdonald, IA, Eiken, O, Mekjavic, IB
European journal of applied physiology. 2014;(11):2411-25
Abstract
PURPOSE This study tested the hypothesis that hypoxia exacerbates reductions in body mass observed during unloading. METHODS To discern the separate and combined effects of simulated microgravity and hypoxia, 11 healthy males underwent three 21-day campaigns in a counterbalanced fashion: (1) normoxic bed rest (NBR; FiO₂ = 0.209; PiO₂ = 133.1 ± 0.3); (2) hypoxic ambulatory confinement (HAMB; FiO₂ = 0.141 ± 0.004; PiO₂ = 90.0 ± 0.4; ~4,000 m); and (3) hypoxic bed rest (HBR; FiO₂ = 0.141 ± 0.004; PiO₂ = 90.0 ± 0.4). The same dietary menu was applied in all campaigns. Targeted energy intakes were estimated individually using the Harris-Benedict equation taking into account whether the subjects were bedridden or ambulatory. Body mass and water balance were assessed throughout the campaigns. Whole body and regional body composition was determined before and after the campaigns using dual-energy X-ray absorptiometry. Before and during the campaigns, indirect calorimetry and visual analogue scores were employed to assess the resting energy expenditure (REE) and perceived appetite sensations, respectively. RESULTS Energy intakes were lower than targeted in all campaigns (NBR: -5%; HAMB -14%; HBR: -6%; P < 0.01). Body mass significantly decreased following all campaigns (NBR: -3%; HAMB -4%; HBR: -5%; P < 0.01). While fat mass was not significantly altered, the whole body fat free mass was reduced (NBR: -4%; HAMB -5%; HBR: -5%; P < 0.01), secondary to lower limb fat-free mass reduction. Water balance was comparable between the campaigns. No changes were observed in REE and perceived appetite. CONCLUSIONS Exposure to simulated altitude of ~4,000 m does not seem to worsen the whole body mass and fat-free mass reductions or alter resting energy expenditure and appetite during a 21-day simulated microgravity.
-
8.
Spaceflight-induced bone loss: is there an osteoporosis risk?
Sibonga, JD
Current osteoporosis reports. 2013;(2):92-8
Abstract
Currently, the measurement of areal bone mineral density (aBMD) is used at NASA to evaluate the effects of spaceflight on the skeletal health of astronauts. Notably, there are precipitous declines in aBMD with losses >10 % detected in the hip and spine in some astronauts following a typical 6-month mission in space. How those percentage changes in aBMD relate to fracture risk in the younger-aged astronaut is unknown. Given the unique set of risk factors that could be contributing to this bone loss (eg, adaptation to weightlessness, suboptimal diet, reduced physical activity, perturbed mineral metabolism), one might not expect skeletal changes due to spaceflight to be similar to skeletal changes due to aging. Consequently, dual-energy X-ray absorptiometry (DXA) measurement of aBMD may be too limiting to understand fracture probability in the astronaut during a long-duration mission and the risk for premature osteoporosis after return to Earth. Following a brief review of the current knowledge-base, this paper will discuss some innovative research projects being pursued at NASA to help understand skeletal health in astronauts.
-
9.
[Mechanism of weightlessness osteoporosis and preventive and therapeutic effect of traditional Chinese medicine].
Zhu, B, Guo, H, Hao, XJ, Fu, Q, Hu, SM
Zhongguo gu shang = China journal of orthopaedics and traumatology. 2012;(7):611-6
Abstract
Weightlessness environment can lead to the muscle atrophy and body fluid distribution upward,which can cause the bone calcium metabolism disorder and always accompanied by the loss of bone microstructure and increased rate of bone fracture. Under microgravity,the astronauts are much easier to decrease the Ca2+ ion in bone, which can cause serious osteoporosis. However the bone lost is not equilibrium, it is especially serious in the mechanism loading bone and the recovery process is more difficult. These are very different from the osteoporosis in older people and postmenopausal osteoporosis. It is necessary to find an optimal method to due with it. In traditional Chinese medicine theory,the kidney stores "Jing" and dominates the bone, thus a lot of bone related diseases can be treated through the kidney. A lot of clinical practices have also proved that the Chinese herbs used under the guidance of basic Chinese medicine theory are always good at the treatment of common osteoporosis. In simulated weightlessness experiment, people found that the kidney nourishment drugs do can prevent the decrease of BMD. So in this article we want to review the causes of weightlessness and the potentials applications of tradition Chinese medicine in the treatment of weightlessness osteoporosis.
-
10.
[Kidney stone formation during space flight and long-term bed rest].
Okada, A, Ichikawa, J, Tozawa, K
Clinical calcium. 2011;(10):1505-10
Abstract
Microgravity environment like space flight or a condition requiring long-term bed-rest increase bone resorption and decrease bone formation, inducing the rapid decrease of bone minerals to osteoporosis. Bone mineral loss increases urinary calcium excretion and the risk of urinary stone formation. To clarify the influence of the conditions on renal stone formation, a 90-day bed rest test was performed to analyze the mechanism of microgravity or bed rest-induced stone formation and prevention by bisphosphonate medication and bed-rest exercise. As the results, renal stone formation was observed in control and exercise groups and no stone was seen in the medication group. In the medication group, urinary calcium excretion and relative supersaturation of calcium oxalate were lower than in the control group throughout the bed-rest and recovery period. Bisphosphonate is useful for the prevention of renal stone formation during space flight and long-term bed-rest.