模拟微重力环境下暴露于男女两性的铁代谢调节：来自随机试验人工重力卧床休息-欧洲航天局（AGBRESA）的结果。
Iron metabolism regulation in females and males exposed to simulated microgravity: results from the randomized trial Artificial Gravity Bed Rest-European Space Agency (AGBRESA).
机构信息
Laboratory "Movement Sport and Health Sciences" EA7470, University of Rennes/ENS Rennes, Bruz, France; Nutrition, Metabolism, and Cancer (NuMeCan) Institute, National Institute of Health and Medical Research (INSERM), University of Rennes, National Research Institute for Agriculture, Food and the Environment (INRAE), UMR 1241, AEM2 platform, Rennes, France.
Nutrition, Metabolism, and Cancer (NuMeCan) Institute, National Institute of Health and Medical Research (INSERM), University of Rennes, National Research Institute for Agriculture, Food and the Environment (INRAE), UMR 1241, AEM2 platform, Rennes, France; Department of Biochemistry, Rennes University Hospital (CHU Rennes), Rennes, France.
出版信息
Am J Clin Nutr. 2022 Nov;116(5):1430-1440. doi: 10.1093/ajcn/nqac205. Epub 2023 Feb 10.
BACKGROUND
Iron metabolism imbalance could contribute to physical deconditioning experienced by astronauts due to its essential role in energy metabolism, cellular respiration, and oxygen transport.
OBJECTIVES
In this clinical exploratory study, we wanted to determine whether artificial gravity (AG) training modulated iron metabolism, RBC indices, and body lean mass in healthy male and female participants exposed to head-down tilt (HDT) bed rest, the reference ground-based model of microgravity.
METHODS
We recruited 8 healthy female and 16 healthy male participants who were all exposed to HDT bed rest for 60 d. In addition, they were assigned to 3 experimental groups (n = 8/each): controls, continuous AG training in a short-arm centrifuge (1 × 30 min/d), and intermittent AG training (6 × 5 min/d).
RESULTS
The iron metabolism responses to simulated microgravity of the AG training groups did not differ significantly from the responses of controls. Independently from AG, we found that both serum iron concentrations (+31.3%, P = 0.027) and transferrin saturation levels (+28.4%, P = 0.009) increased in males after 6 d of HDT bed rest, as well as serum hepcidin concentrations (+36.9%, P = 0.005). The increase of transferrin saturation levels persisted after 57 d of HDT bed rest (+13.5%, P = 0.026), suggesting that long-term exposure to microgravity sustainably increases serum iron availability in males, and consequently the risk of iron excess or misdistribution. In females, 6 and 57 d of HDT bed rest did not significantly change serum iron, transferrin saturation, or hepcidin levels.
CONCLUSIONS
The data from this exploratory study suggest that 1) AG training does not influence the iron metabolism responses to microgravity; and 2) iron metabolism parameters, especially iron availability for cells, are significantly increased in males, but not in females, exposed to long-term simulated microgravity. Because of the small sample size of females, we nevertheless must be cautious before concluding that iron metabolism could differently respond to microgravity in females. This trial was registered at https://www.drks.de as DRKS00015677.
背景
铁代谢失衡可能导致宇航员身体机能下降，因为铁在能量代谢、细胞呼吸和氧气运输中起着至关重要的作用。
目的
在这项临床探索性研究中，我们想确定人工重力（AG）训练是否能调节铁代谢、红细胞指数和瘦体重，这些都是健康男性和女性参与者在模拟微重力环境下接受头低位卧床休息（HDT）的基础模型。
方法
我们招募了 8 名健康女性和 16 名健康男性参与者，他们都接受了 60 天的 HDT 卧床休息。此外，他们被分为 3 个实验组（每组 8 人）：对照组、短臂离心机连续 AG 训练（1×30 分钟/天）和间歇 AG 训练（6×5 分钟/天）。
结果
AG 训练组模拟微重力对铁代谢的反应与对照组无显著差异。独立于 AG，我们发现男性在接受 6 天 HDT 卧床休息后，血清铁浓度（增加 31.3%，P=0.027）和转铁蛋白饱和度（增加 28.4%，P=0.009）均升高，血清 hepcidin 浓度（增加 36.9%，P=0.005）也升高。HDT 卧床休息 57 天后，转铁蛋白饱和度水平仍持续升高（增加 13.5%，P=0.026），这表明长期暴露于微重力会持续增加男性血清铁的可用性，从而增加铁过多或分布不均的风险。在女性中，6 天和 57 天的 HDT 卧床休息并未显著改变血清铁、转铁蛋白饱和度或 hepcidin 水平。
结论
这项探索性研究的数据表明：1）AG 训练不影响微重力对铁代谢的反应；2）暴露于长期模拟微重力的男性铁代谢参数，特别是细胞铁的可用性显著增加，而女性则没有。由于女性样本量较小，因此在得出女性铁代谢对微重力可能有不同反应的结论之前，我们必须谨慎。该试验在 https://www.drks.de 注册，编号为 DRKS00015677。
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