Abstract Bone loss and renal stone risk are longstanding concerns for astronauts. Bone resorption brought on by spaceflight elevates urinary calcium and the risk of renal stone formation. Loss of ...bone calcium leads to concerns about fracture risk and increased long-term risk of osteoporosis. Bone metabolism involves many factors and is interconnected with muscle metabolism and diet. We report here bone biochemistry and renal stone risk data from astronauts on 4- to 6-month International Space Station missions. All had access to a type of resistive exercise countermeasure hardware, either the Advanced Resistance Exercise Device (ARED) or the Interim Resistance Exercise Device (iRED). A subset of the ARED group also tested the bisphosphonate alendronate as a potential anti-resorptive countermeasure (Bis + ARED). While some of the basic bone marker data have been published, we provide here a more comprehensive evaluation of bone biochemistry with a larger group of astronauts. Regardless of exercise, the risk of renal stone formation increased during spaceflight. A key factor in this increase was urine volume, which was lower during flight in all groups at all time points. Thus, the easiest way to mitigate renal stone risk is to increase fluid consumption. ARED use increased bone formation without changing bone resorption, and mitigated a drop in parathyroid hormone in iRED astronauts. Sclerostin, an osteocyte-derived negative regulator of bone formation, increased 10–15% in both groups of astronauts who used the ARED ( p < 0.06). IGF-1, which regulates bone growth and formation, increased during flight in all 3 groups ( p < 0.001). Our results are consistent with the growing body of literature showing that the hyper-resorptive state of bone that is brought on by spaceflight can be countered pharmacologically or mitigated through an exercise-induced increase in bone formation, with nutritional support. Key questions remain about the effect of exercise-induced alterations in bone metabolism on bone strength and fracture risk.
INTRODUCTION: The year-long mission of American astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko included the most complex biomedical experiments ever conducted on the International ...Space Station-and arguably in human spaceflight-to establish insight
into human health risks of interplanetary exploration. Focusing on risk mitigation, NASA conducted investigations that addressed spaceflight health hazards to varying degrees. This pilot mission was initiated to gain further knowledge and monitor the physiological, psychological, and medical
effects of long-duration exposure to spaceflight.METHODS: NASA's Human Research Program and the Russian Academy of Sciences' Institute of Biomedical Problems identified more than 20 biomedical risk-reduction research investigations to be conducted on the two crewmembers
before, during, and after their yearlong expedition. A database of results, as well as observations on programmatic resources, was collected to understand essential elements for future spaceflight health studies.RESULTS: Statistical rigor requires additional testing at a length
of 1 yr to demonstrate the presence or absence of unacceptable deleterious effects, and to permit extrapolation to longer durations in space. Review of experimental procedures from this mission suggests potential efficiencies for future investigations.DISCUSSION: The Kelly-Kornienko
1-yr mission demonstrated the importance of continuing joint investigations with the adoption of standard measures for rigorous comparisons across disparate populations. It identified improvements to collaborative processes across national and international scientific research programs. Additional
studies will inform the development of an integrated applied research methodology for the space station and future interplanetary expeditions.Charles JB, Pietrzyk RA. A year on the International Space Station: implementing a long-duration biomedical research mission. Aerosp Med Hum Perform. 2019; 90(1):4-11.
Purpose Exposure to microgravity affects human physiology and results in changes in urinary chemical composition during and after spaceflight, favoring an increased risk of renal stones. We assessed ...the efficacy of potassium citrate to decrease the stone risk during and after spaceflight. Materials and Methods The study was done in 30 long duration spaceflight crew members to the space stations Mir and International Space Station. Before, during and after spaceflight 24-hour urine samples were collected to assess the renal stone risk. Potassium citrate (20 mEq) was ingested daily by International Space Station crew members in a double-blind, placebo controlled study. Mir crew members performed the identical protocol but did not ingest medication. Results Potassium citrate treated crew members had decreased urinary calcium excretion and maintained the calcium oxalate supersaturation risk at preflight levels compared to that in controls. Increased urinary pH in the treatment group decreased the risk of uric acid stones. Conclusions Results from this investigation suggest that supplementation with potassium citrate may decrease the risk of renal stone formation during and immediately after spaceflight.
To understand the health impact of long-duration spaceflight, one identical twin astronaut was monitored before, during, and after a 1-year mission onboard the International Space Station; his twin ...served as a genetically matched ground control. Longitudinal assessments identified spaceflight-specific changes, including decreased body mass, telomere elongation, genome instability, carotid artery distension and increased intima-media thickness, altered ocular structure, transcriptional and metabolic changes, DNA methylation changes in immune and oxidative stress-related pathways, gastrointestinal microbiota alterations, and some cognitive decline postflight. Although average telomere length, global gene expression, and microbiome changes returned to near preflight levels within 6 months after return to Earth, increased numbers of short telomeres were observed and expression of some genes was still disrupted. These multiomic, molecular, physiological, and behavioral datasets provide a valuable roadmap of the putative health risks for future human spaceflight.
The formation of a renal stone during space flight may have serious negative effects on the health of the crewmember and the success of the mission. Urinary biochemical factors and the influence of ...dietary factors associated with renal stone development were assessed during long duration Mir Space Station missions.
Twenty-four-hour urine samples were collected prior to, during and following long duration space flight. The relative urinary supersaturation of calcium oxalate, calcium phosphate (brushite), sodium urate, struvite and uric acid were determined.
Changes in the urinary biochemistry of crewmembers during long duration spaceflight demonstrated increases in the supersaturation of the stone-forming salts. In-flight hypercalciuria was evident in a number of individual crewmembers and 24-hour dietary fluid intake and urine volume were significantly lower. During flight, there was a significant increase in brushite supersaturation.
These data suggest acute effects of space flight and postflight changes in the urinary biochemistry favoring increased crystallization in the urine. The effects of dietary intake, especially fluid intake, may have a significant impact on the potential for renal stone formation. Efforts are now underway to assess the efficacy of a countermeasure to mitigate the increased risk.
The metabolic and environmental factors influencing renal stone formation before, during, and after Space Shuttle flights were assessed. We established the contributing roles of dietary factors in ...relationship to the urinary risk factors associated with renal stone formation.
24-hr. urine samples were collected prior to, during space flight, and following landing. Urinary and dietary factors associated with renal stone formation were analyzed and the relative urinary supersaturation of calcium oxalate, calcium phosphate (brushite), sodium urate, struvite and uric acid were calculated.
Urinary composition changed during flight to favor the crystallization of calcium-forming salts. Factors that contributed to increased potential for stone formation during space flight were significant reductions in urinary pH and increases in urinary calcium. Urinary output and citrate, a potent inhibitor of calcium-containing stones, were slightly reduced during space flight. Dietary intakes were significantly reduced for a number of variables, including fluid, energy, protein, potassium, phosphorus and magnesium.
This is the first in-flight characterization of the renal stone forming potential in astronauts. With the examination of urinary components and nutritional factors, it was possible to determine the factors that contributed to increased risk or protected from risk. In spite of the protective components, the negative contributions to renal stone risk predominated and resulted in a urinary environment that favored the supersaturation of stone-forming salts. Dietary and pharmacologic therapies need to be assessed to minimize the potential for renal stone formation in astronauts during/after space flight.
Steven F.
Siconolfi 1 ,
Randal J.
Gretebeck 2 ,
William W.
Wong 3 ,
Robert A.
Pietrzyk 4 , and
Sheril S.
Suire 2
1 Exercise Physiology Laboratory,
Space Biomedical Research Institute, National ...Aeronautics and Space
Administration, Johnson Space Center, Houston 77058;
2 University Space Research Association,
Houston 77058; 3 Stable Isotope Program,
United States Department of Agriculture/ Agricultural Research Service
Children's Nutrition Research Center, Department of Pediatrics, Baylor
College of Medicine, Houston 77030;
4 Biochemistry Research Laboratory, KRUG
Life Sciences, Biomedical Operations and Research Branch, National
Aeronautics and Space Administration, Houston, Texas
77058
Received 21 November 1994; accepted in final form 11 July 1996.
Siconolfi, Steven F., Randal J. Gretebeck, William W. Wong,
Robert A. Pietrzyk, and Sheril S. Suire. Assessing total body and
extracellular water from bioelectrical response spectroscopy. J. Appl. Physiol. 82(2): 704-710, 1997. We developed and validated assessments for total body water
(TBW) and extracellular water (ECW) by using two resistance values of a
new electric circuit model (CM) (two resistors: a capacitor and an
inductor) with or without body mass. Fluid shifts occurring after 40 min of supine rest did not decrease the validity of either estimate. CM
estimates were valid; r = 0.941 to
0.969, low SE of estimates of 1.15-2.28 kg, nonsignificant mean
differences (CM dilution; % = 0.4 to 1.3%) that
were close to the expected measurement errors for TBW (±1%) and
ECW (±5%), and Bland-Altman pairwise comparisons that showed
equivalence between methods. The CM estimates of TBW and ECW had
marginally better validity than the previously published bioimpedance
models. The advantage of the CM model is its assessments of multiple
fluid spaces and that it does not require gender-specific equations. We
conclude that CM estimate of TBW is acceptable, whereas further
validation is needed before the ECW estimate should be used in a
clinical or research setting.
bioimpedance; frequency; body fluids
A high-performance liquid chromatographic method was developed as an alternative to automated enzymatic analysis of uric acid in human urine preserved with thymol and/or thimerosal. Uric acid (t
R = ...10min) and creatinine (t
R = 5min) were separated and quantified during isocratic elution (0.025M acetate buffer, pH 4.5) from a μBondapak C
18 column. The uric-acid peak was identified chemically by incubating urine samples with uricase. The thymol/thimerosal peak appeared at 31 min during the washing step and did not interfere with the analysis. We validated the high-performance liquid chromatographic method for linearity, precision and accuracy, and the results were found to be excellent.
Renal stone formation among astronauts Pietrzyk, Robert A; Jones, Jeffrey A; Sams, Clarence F ...
Aviation, space, and environmental medicine
78, Številka:
4 Suppl
Journal Article
With the continued construction of the International Space Station, humans are living longer in the microgravity environment of space. However, many questions still exist as to the physiological ...effects of spaceflight on the human body. Bone loss, cardiovascular changes, and muscle atrophy are well-documented health risks to humans during spaceflight. Another potential serious health complication is the development of renal stones. The development of a renal stone may not only impact the health of the crewmember, but also the success of the mission.
A retrospective analysis of astronaut data from 24-h urine samples collected prior to launch and immediately after landing was performed. Urine characteristics associated with renal stone formation were analyzed and the relative injury supersaturations of stone-forming constituents calculated.
In the current study, previously collected data to identify urinary factors associated with renal stone formation demonstrated an increased risk in astronauts who had actually formed a renal stone. Increased urinary supersaturation of the stone-forming salts was observed in those astronauts who formed renal stones. Similar changes in urinary supersaturation were noted among many astronauts after landing, indicating an increased postflight risk for stone formation.
An assessment program should be undertaken to identify and evaluate astronauts with elevated risk factors prior to flight and immediately following landing. Individualized recommendations can be prescribed to astronauts and may include dietary changes, increased fluid intake, or medications to minimize the risk of stone formation.
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