Volume regulating hormone responses to repeated head-up tilt and lower body negative pressure

Roessler, Andreas; Goswami, Nandu; Haditsch, Bernd; Loeppky, Jack A.; Luft, Friedrich C.; Hinghofer‐Szalkay, Helmut

doi:10.1111/j.1365-2362.2011.02476.x

Cited by 16 publications

(19 citation statements)

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“…This implies a dissociation of the aldosterone level and renin response under the particular conditions of parabolic flight. Interestingly, dissociation of plasma aldosterone levels and plasma renin activity has previously been reported in subjects experiencing presyncope and in subjects undergoing repeated orthostatic challenges by tilt table testing and lower body negative pressure (LBNP) tests (Roessler et al 2011; Hinghofer-Szalkay et al 2011). The works of Roessler et al and Hinghofer-Szalkay et al indicate furthermore that during orthostatic challenge aldosterone is rather controlled by adrenocorticotropic hormone (ACTH) than by renin, which may serve as an explanation of the dissociated aldosterone–renin response in parabolic flight.…”

Section: Discussionmentioning

confidence: 95%

“…It is well known that levels of AVP and cortisol are extensively increased in motion sickness; therefore, the CT- pro AVP and cortisol values of the motion-sick subjects were excluded from the statistical analysis of the blood hormones, and individual data are shown instead. Furthermore, we did not analyze blood levels of ACTH what might had allowed us to identify a close relationship between ACTH and aldosterone in parabolic flight as it is known for orthostatic stress during tilting and LBNP (Roessler et al 2011; Hinghofer-Szalkay et al 2011). Fifth , rebreathings at 0 G z fell into the early 0 G z phases, which are characterized by a sympathetic withdrawal and acute activation of the vagal nervous system.…”

Section: Limitationsmentioning

confidence: 99%

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Interactions of the human cardiopulmonary, hormonal and body fluid systems in parabolic flight

et al. 2014

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healthy subjects in the standing position while they were in parabolic flight at 0 and 1.8 g z . Plasma volume (PV) and fluid regulating blood hormones were determined five times over the flight day. Eleven out of the 18 subjects were subjected to an identical test protocol in a hypobaric chamber in ambient conditions comparable to parabolic flight. Results cI rb in 0 g z decreased significantly during flight (early, 5.139 ± 1.326 l/min; late, 4.150 ± 1.082 l/ min) because of a significant decrease in heart rate (Hr) (early, 92 ± 15 min −1 ; late, 78 ± 12 min −1), even though the stroke volume (SV) remained the same. HH produced a small decrease in the PV, both in the hypobaric chamber and in parabolic flight, indicating a dominating HH effect without a significant effect of gt on PV (−52 ± 34 and −115 ± 32 ml, respectively). Pulmonary tissue volume decreased in the HH conditions because of hypoxic pulmonary vasoconstriction (0.694 ± 0.185 and 0.560 ± 0.207 ml) but increased at 0 and 1.8 g z in parabolic flight (0.593 ± 0.181 and 0.885 ± 0.458 ml, respectively), indicating that cardiac output and arterial blood pressure rather than HH are the main factors affecting pulmonary vascular regulation in parabolic flight. Conclusion HH and gt each lead to specific responses of the cardiovascular system in parabolic flight. Whereas HH seems to be mainly responsible for the PV decrease in flight, gt overrides the hypoxic pulmonary vasoconstriction induced by HH. this finding indicates the need for careful and individual medical examination and, if necessary, health status improvement for each individual considering a parabolic flight, given the effects of the combination of HH and gt in flight.Keywords Inert gas rebreathing · Weightlessness · Hypobaric hypoxia · Hypobaric chamber · gravity AbstractPurpose commercial parabolic flights accessible to customers with a wide range of health states will become more prevalent in the near future because of a growing private space flight sector. However, parabolic flights present the passengers' cardiovascular system with a combination of stressors, including a moderately hypobaric hypoxic ambient environment (HH) and repeated gravity transitions (gt). thus, the aim of this study was to identify unique and combined effects of HH and gt on the human cardiovascular, pulmonary and fluid regulation systems. Methods cardiac index was determined by inert gas rebreathing (cI rb ), and continuous non-invasive finger blood pressure (FBP) was repeatedly measured in 18 communicated by guido Ferretti.Electronic supplementary material the online version of this article

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Section: Discussionmentioning

confidence: 95%

Section: Limitationsmentioning

confidence: 99%

Interactions of the human cardiopulmonary, hormonal and body fluid systems in parabolic flight

et al. 2014

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“…These results may have clinical and spaceflight applications X [50] We speculate that the observed differences in blood pressure and hormonal responses to LBNP and HUT are caused by divergent effects of blood pooling in the splanchnic region, despite similar reductions in splanchnic perfusion. Apparently with repeated central hypovolaemia, especially by the 3rd application of stress, plasma aldosterone levels rise (along with ACTH), conceivably increasing its volume-guarding effect X [51] We conclude that during the 20-min supine post-syncopal period, plasma volume, plasma renin activity (PRA) and adrenomedullin and vasopressin (AVP) return closer to baseline but aldosterone and ACTH continue increasing.…”

mentioning

confidence: 78%

“…In [50], we reported that both adrenocorticotropic hormone and aldosterone progressively increased with repeated stresses and were elevated above baseline values during each rest period.…”

Section: Evsyukova)mentioning

confidence: 95%

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Research update for articles published in EJCI in 2011

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Assimakopoulos

et al. 2013

Eur J Clin Investigation

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Comparison between men and women of volume regulating hormones and aquaporin-2 excretion following graded central hypovolemia

et al. 2018

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Central hypovolemia induced by orthostatic loading causes reno-vascular changes that can lead to orthostatic intolerance. In this study, we investigated volume regulating hormonal responses and reno-vascular changes in male and female subjects as they underwent central hypovolemia, induced by graded lower body negative pressure (LBNP). Aquaporin-2 (AQP2) excretion was measured as a biomarker for the renal system response to vasopressin. 37 young healthy subjects (n = 19 males; n = 18 females) were subjected to graded LBNP until -40 mmHg LBNP. Under resting conditions, males had significantly higher copeptin (a stable peptide derived from vasopressin) levels compared with females. Adrenocorticotropin (ACTH), adrenomedullin (ADM), vasopressin (AVP) and brain natriuretic peptide (BNP) were not affected by our experimental protocol. Nevertheless, an analysis of ADM and BNP with the data normalized as percentages of the baseline value data showed an increase from baseline to 10 min after recovery in the males in ADM and in the females in BNP.Analysis of BNP and ADM raise the possibility of a preferential adaptive vascular response to central hypovolemia in males as shown by the normalized increase in ADM, whereas females showed a preferential renal response as shown by the normalized increase in BNP. Furthermore, our results suggest that there might be a difference between men and women in the Copeptin response to alterations in orthostatic loading, simulated either by using LBNP or during posture changes.

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Volume regulating hormone responses to repeated head-up tilt and lower body negative pressure

Cited by 16 publications

References 27 publications

Interactions of the human cardiopulmonary, hormonal and body fluid systems in parabolic flight

Interactions of the human cardiopulmonary, hormonal and body fluid systems in parabolic flight

Research update for articles published in EJCI in 2011

Comparison between men and women of volume regulating hormones and aquaporin-2 excretion following graded central hypovolemia

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