This study aimed to measure hemolysis before, during and after 60 days of the ground-based spaceflight analog bed rest and the effect of a nutritional intervention through a prospective randomized clinical trial. Twenty male participants were hospitalized for 88 days comprised of 14 days of ambulatory baseline, 60 days of 6° head-down tilt bed rest and 14 days of reambulation. Ten participants each received a control diet or daily polyphenol associated with omega-3, vitamin E, and selenium supplements. The primary outcome was endogenous carbon monoxide (CO) elimination measured by gas chromatography. Hemolysis was also measured with serial bilirubin, iron, transferrin saturation blood levels and serial 3-day stool collections were used to measure urobilinoid excretion using photometry. Total hemoglobin mass (tHb) was measured using CO-rebreathing. CO elimination increased after 5, 11, 30, and 57 days of bed rest: +289 ppb (95% CI 101–477 ppb; p = 0.004), +253 ppb (78–427 ppb; p = 0.007), +193 ppb (89–298 ppb; p = 0.001) and +858 ppb (670–1046 ppb; p < 0.000), respectively, compared to baseline. Bilirubin increased after 20 and 49 days of bed rest +0.8 mg/l (p = 0.013) and +1.1 mg/l (p = 0.012), respectively; and iron increased after 20 days of bed rest +10.5 µg/dl (p = 0.032). The nutritional intervention did not change CO elimination. THb was lower after 60 days of bed rest −0.9 g/kg (p = 0.001). Bed rest enhanced hemolysis as measured through all three by-products of heme oxygenase. Ongoing enhanced hemolysis over 60 days contributed to a 10% decrease in tHb mass. Modulation of red blood cell control towards increased hemolysis may be an important mechanism causing anemia in astronauts.

本研究旨在通过前瞻性随机临床试验测量陆基太空飞行模拟卧床休息 60 天之前、期间和之后的溶血情况以及营养干预的效果。20 名男性参与者住院 88 天，包括 14 天的动态基线、60 天的 6° 头向下倾斜卧床休息和 14 天的再走动。十名参与者每人接受对照饮食或每日与 omega-3、维生素 E 和硒补充剂相关的多酚。主要结果是通过气相色谱法测量的内源性一氧化碳 (CO) 消除。还用系列胆红素、铁、转铁蛋白饱和血液水平测量溶血，并且系列 3 天粪便收集用于使用光度法测量类尿胆素排泄。使用 CO 再呼吸测量总血红蛋白质量 (tHb)。p  = 0.004)、+253 ppb (78–427 ppb；p  = 0.007)、+193 ppb (89–298 ppb；p  = 0.001) 和 +858 ppb (670–1046 ppb；p  < 0.000)，分别进行比较到基线。胆红素在卧床休息 20 天和 49 天后分别增加 +0.8 mg/l ( p  = 0.013) 和 +1.1 mg/l ( p  = 0.012)；卧床休息 20 天后铁增加 +10.5 µg/dl ( p  = 0.032)。营养干预并未改变 CO 消除。卧床休息 60 天后 THb 降低 -0.9 g/kg ( p = 0.001）。通过血红素加氧酶的所有三种副产物测量，卧床休息增强了溶血作用。持续超过 60 天的溶血增强导致 tHb 质量降低 10%。调节红细胞控制以增加溶血可能是导致宇航员贫血的重要机制。