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Tahimic CGT, Paul AM, Schreurs AS, Torres SM, Rubinstein L, Steczina S, Lowe M, Bhattacharya S, Alwood JS, Ronca AE, Globus RK. Influence of Social Isolation During Prolonged Simulated Weightlessness by Hindlimb Unloading. Front Physiol 2019; 10:1147. [PMID: 31572207 PMCID: PMC6753329 DOI: 10.3389/fphys.2019.01147] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 08/22/2019] [Indexed: 12/15/2022] Open
Abstract
The hindlimb unloading (HU) model has been used extensively to simulate the cephalad fluid shift and musculoskeletal disuse observed in spaceflight with its application expanding to study immune, cardiovascular and central nervous system responses, among others. Most HU studies are performed with singly housed animals, although social isolation also can substantially impact behavior and physiology, and therefore may confound HU experimental results. Other HU variants that allow for paired housing have been developed although no systematic assessment has been made to understand the effects of social isolation on HU outcomes. Hence, we aimed to determine the contribution of social isolation to tissue responses to HU. To accomplish this, we developed a refinement to the traditional NASA Ames single housing HU system to accommodate social housing in pairs, retaining desirable features of the original design. We conducted a 30-day HU experiment with adult, female mice that were either singly or socially housed. HU animals in both single and social housing displayed expected musculoskeletal deficits versus housing matched, normally loaded (NL) controls. However, select immune and hypothalamic-pituitary-adrenal (HPA) axis responses were differentially impacted by the HU social environment relative to matched NL controls. HU led to a reduction in % CD4+ T cells in singly housed, but not in socially housed mice. Unexpectedly, HU increased adrenal gland mass in socially housed but not singly housed mice, while social isolation increased adrenal gland mass in NL controls. HU also led to elevated plasma corticosterone levels at day 30 in both singly and socially housed mice. Thus, musculoskeletal responses to simulated weightlessness are similar regardless of social environment with a few differences in adrenal and immune responses. Our findings show that combined stressors can mask, not only exacerbate, select responses to HU. These findings further expand the utility of the HU model for studying possible combined effects of spaceflight stressors.
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Affiliation(s)
- Candice G T Tahimic
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States.,KBR, Houston, TX, United States
| | - Amber M Paul
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States.,Universities Space Research Association, Columbia, MD, United States
| | - Ann-Sofie Schreurs
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States.,KBR, Houston, TX, United States
| | - Samantha M Torres
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States.,Blue Marble Space Institute of Science, Seattle, WA, United States
| | - Linda Rubinstein
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States.,Universities Space Research Association, Columbia, MD, United States
| | - Sonette Steczina
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States.,Blue Marble Space Institute of Science, Seattle, WA, United States
| | - Moniece Lowe
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States.,Blue Marble Space Institute of Science, Seattle, WA, United States
| | - Sharmila Bhattacharya
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States
| | - Joshua S Alwood
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States
| | - April E Ronca
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States.,Department of Obstetrics and Gynecology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Ruth K Globus
- Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, United States
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Liu J, Li Y, Verheyden B, Chen S, Chen Z, Gai Y, Liu J, Gao J, Xie Q, Yuan M, Li Q, Li L, Aubert AE. Is autonomic modulation different between European and Chinese astronauts? PLoS One 2015; 10:e0120920. [PMID: 25799561 PMCID: PMC4370477 DOI: 10.1371/journal.pone.0120920] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Accepted: 02/09/2015] [Indexed: 11/29/2022] Open
Abstract
Purpose The objective was to investigate autonomic control in groups of European and Chinese astronauts and to identify similarities and differences. Methods Beat-to-beat heart rate and finger blood pressure, brachial blood pressure, and respiratory frequency were measured from 10 astronauts (five European taking part in three different space missions and five Chinese astronauts taking part in two different space missions). Data recording was performed in the supine and standing positions at least 10 days before launch, and 1, 3, and 10 days after return. Cross-correlation analysis of heart rate and systolic pressure was used to assess cardiac baroreflex modulation. A fixed breathing protocol was performed to measure respiratory sinus arrhythmia and low-frequency power of systolic blood pressure variability. Results Although baseline cardiovascular parameters before spaceflight were similar in all astronauts in the supine position, a significant increase in sympathetic activity and a decrease in vagal modulation occurred in the European astronauts when standing; spaceflight resulted in a remarkable vagal decrease in European astronauts only. Similar baseline supine and standing values for heart rate, mean arterial pressure, and respiratory frequency were shown in both groups. Standing autonomic control was based on a balance of higher vagal and sympathetic modulation in European astronauts. Conclusion Post-spaceflight orthostatic tachycardia was observed in all European astronauts, whereas post-spaceflight orthostatic tachycardia was significantly reduced in Chinese astronauts. The basis for orthostatic intolerance is not apparent; however, many possibilities can be considered and need to be further investigated, such as genetic diversities between races, astronaut selection, training, and nutrition, etc.
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Affiliation(s)
- Jiexin Liu
- Department of Cardiology, Beijing Friendship Hospital, China Capital Medical University, Beijing, China
- Department of Cardiology, University Hospital Gasthuisberg, K. U. Leuven, Leuven, Belgium
- * E-mail: (JL); (MY)
| | | | - Bart Verheyden
- Department of Cardiology, University Hospital Gasthuisberg, K. U. Leuven, Leuven, Belgium
| | | | | | | | | | | | - Qiong Xie
- China Astronaut Center, Beijing, China
| | - Ming Yuan
- China Astronaut Center, Beijing, China
- * E-mail: (JL); (MY)
| | - Qin Li
- Department of Cardiology, Beijing Friendship Hospital, China Capital Medical University, Beijing, China
| | - Li Li
- Department of Cardiology, Beijing Friendship Hospital, China Capital Medical University, Beijing, China
| | - André E. Aubert
- Department of Cardiology, University Hospital Gasthuisberg, K. U. Leuven, Leuven, Belgium
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cAMP and cGMP in human parotid saliva: relationships to taste and smell dysfunction, gender, and age. Am J Med Sci 2008; 334:431-40. [PMID: 18091364 DOI: 10.1097/maj.0b013e3180de4d97] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Among the chemical moieties present in human parotid saliva, some, such as gustin or carbonic anhydrase VI, have been useful to distinguish patients with taste and smell dysfunction from normal subjects. To continue these studies we compared levels of salivary cAMP and cGMP in patients with taste and smell dysfunction with those in normal subjects. We were also interested in exploring physiological characteristics of salivary cAMP and cGMP including changes with gender and age because previous studies had not clearly defined these issues. To perform these studies parotid saliva was collected from 61 normal volunteers and 253 patients with taste and smell dysfunction. cAMP and cGMP were measured by a spectrophotometric 96 plate ELISA technique; parotid salivary protein and flow rate were also measured. Both cAMP and cGMP were found in saliva of normal subjects and patients in the detection range of the assay used. In patients mean concentrations of both cAMP and cGMP were lower than in normal subjects; for cAMP levels were lower among both men and women patients. cAMP was 7 to 10 times higher than cGMP in both normal subjects and patients. Concentrations of cAMP were consistently higher in normal women than in normal men. cAMP levels were generally lower and cGMP levels were generally higher than in previously reported studies. There was a complex pattern of change for both cAMP and cGMP with age with concentrations increasing to about age 50, then decreasing, then increasing again at age >70 years.
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