sodium load in microgravity standardized study conditions ... · ad in microgravity standardized...
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SOLO SOdium LOad in microgravity
Standardized Study Conditions on the ISS and on Earth
Dr. Petra Frings-Meuthen DLR, Institute of Aerospace Medicine
Study managementStudy protocol
Volunteer selectionVolunteer rules
ISS experimentsBed rest studiesaccording to
ESA standardization plan
(Para) Medical CareNutrition
Biological samplesData management
n = 6-8, COLUMBUSSOLO
Common High salt intake+ controlled diet
Low salt intake+ controlled diet
day 1 day 5 day 1 day 5
• 24-h urine collection• blood draw
• blood gas analysis• body weight measurement
Petra Frings-Meuthen1, Martina Heer2 & Scott Smith3
1DLR, Institut für Luft- und Raumfahrtmedizin, Köln2Universität Bonn, Profil Institute for Clinical Research, Neuss
3NASA Johnson Space Center, Houston, USA
ESA: ELIPS ILSRA-2001-028
• 2 x 5 days inflight•2 x 5 days postflight (R+6-12 months) baseline data collection (BDC)
Sodium retention
microgravityvery high salt
ECV
sodiumexcretion
Sodium retention
without fluid retention
Drummer et al. EJCI 2000; Heer et al AJP 2000
ECV= Extracellular volume
Hypothesis 1
Higher salt intake in microgravity leads to sodiumretention without fluid retention• Sodium balance (intake, excretion)• Water balance, body weight
„High salt intake exacerbates immobilisation induced bone loss accompanied by changes in the acid-base and electrolyte system“
(DLR Salty Life 7 study, 2005)
study days
0 2 4 6 8 10 12 14 16 18 20
urin
ary
CTX
-exc
retio
n (µ
g/d)
0
2000
3000
4000
5000
6000
7000
8000
90000.7 mEq NaCl/kgBW/d7.7 mEq NaCl/kgBW/d6°HDTBR
high vs low salt
p < 0.001ANOVA „treat“
47%
Bed rest period
Frings-Meuthen et al. J Appl Physiol (in press)
Hypothesis 2
Standardisation:Nutrient intake
Environmental conditionsPhysical activity
Sampling & Analysing methods
Higher salt intake exacerbates microgravity induced increased calcium excretion & bone resorption• calcium excretion• bone resorption marker• bone formation marker
Energy (kcal) Protein (g) Fat (g) CH (g) Na (mg) K (mg) H2O (g)BreakfastApple Cider 113 0,1 0 28 29 4 250Cocoa 198 3,1 1 44 144 507 175Sausage Pattie 118 9,8 8 1 589 179 50Split Top Roll 160 4 5 24 300 0 18Grits with Butter 116 2,3 0 26 624 54 125LunchLemonade 82 0 0 20 25 2 250Hot & Sour Soup 65 3,5 1 10 297 132 155Beef Fajitas 159 28,9 4 1 763 453 90Tomatoes & Artichokes 74 2,5 4 8 489 526 191Pears 96 0,3 0 24 21 97 104DinnerPeach Apricot Drink 133 0 0 33 32 2 250Chicken w/ Peanut Sauce 234 22,5 5 25 446 538 64Potatoes au Gratin 147 4,2 8 14 581 157 100Creamed Spinach 65 3,3 2 9 560 245 50Cherry Blueberry Cobbler 308 2,1 9 54 148 184 104SnackApple Cider 113 0,1 0 28 29 4 250Blueberry Raspberry Yoghurt 140 4,5 1 28 50 163 113Almonds 272 11 23 2 305 282 6SUM 2593 102,2 71 379 5432 3529 2345
Energy (kcal) Protein (g) Fat (g) CH (g) Na (mg) K (mg) H2O (g)BreakfastChocolate Breakfast Drink 14 10 1 24 149 532 175Granola w/Blueberries 246 7,4 10 32 53 361 50Berry Medley 97 1,1 0 23 1 165 60Waffles 200 2,9 12 21 149 73 7Orange Drink 112 0 0 28 29 4 250LunchApple Cider 113 0,1 0 28 29 4 250Sweet & Sour Chicken 144 21,5 2 11 192 236 100Potato Medley 101 1,9 2 18 28 212 120Blueberry Raspberry Yoghurt 140 4,5 1 28 50 163 113DinnerPeach Apricot Drink 133 0 0 33 32 2 250Chicken Pineapple Salad 131 10,8 6 7 329 200 75Barbecued Beef Brisket 192 25,4 5 12 368 395 61Green Bean & Potatoes 48 1,6 1 9 206 296 102Cherry Blueberry Cobbler 308 2,1 9 54 148 184 104SnackLemonade 82 0 0 20 25 2 250Macadamia Nuts 312 4,7 27 12 0 117 0Cocoa 198 3,1 1 44 144 507 175SUM 2571 97,1 77 404 1932 3453 2142
High Salt
Low Salt
SOLO Hardware: standardized proceduresMeasuring urine
volume via scaling
Blood gas analysisBody mass measurement
Blood draw
Urine collection
Experiment Status
ISS: 2008BDC: 2009
ISS: 2008BDC: 2011
ISS: 2009BDC: 2010
ISS: 2009BDC: 2010
plannedfor 2011/2012
ISS: 2010BDC: 2011
Sodium intake
experiment days
0
1000
2000
3000
4000
5000
6000
Sodi
um(m
g/d) Low salt
High salt
0
10
20
30
40
50
60
70
80
90
100
ISS low ISS high BDC low BDC high
Sodium balance
More positive sodium balancein space than on earth
Sodi
um(m
mol
/d)
Body weightAstro 1
body
wei
ght (
kg)
0
74
75
76
77
78
79
80
81
82
ISS low ISS high BDC low BDC high
Bod
dy w
eigh
t (kg
)
0
85
86
87
88
89
90
91
92
body
wei
ght (
kg)
0
64
65
66
67
68
69
70
71
72
73
74
75
76
ISS low ISS high BDC low BDC high
subject 2subject 1
subject 3
sodium retention seems to beaccompanied by fluid retention
Water balance to be done
+ 0.8 kg
+ 0.5 kg
+ 0.4 kg
+ 1.25 kg
+ 1.57 kg
+ 1.25 kg
ISS low ISS high BDC low BDC high
0
5
10
15
20
ISS low ISS high BDC low BDC high
0
20
40
60
80
100
120
140
160
180
ISS low ISS high BDC low BDC high
Bone formationbAP (µg/l) PINP (µg/l)
No effect on bone formation with respect to salt intake
Calcium excretion tended to be slightly higher, different reactions regarding bone resorption marker
Conclusion
First scientific ResultsCompletion of this study, with a full complement of subjects, is mandatory to investigate the effects of salt on bone metabolism of astronauts.Sodium retention with or without fluid retention demands further analyses
Standardisation on ISSImplementation in space is more difficult than on earth (technical issues, communication)Mandatory to decrease intra-and inter variation in studies with a small number of test subjects
SOLO Benefits: Importance for space and earth
SOLO will provide information how high salt intake affects thebone turnover in general.
SOLO results will help the nutritional support teams to optimize thefood for crewmembers on long-term missions.
SOLO helps to investigate the influence of a lowmechanical impact and high salt intake on bonemetabolism.
The research will also benefit everybody withlow mechanical loads and high salt intake onearth to prevent osteoporosis.
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