Department of Kinesiology, University of Maryland, College Park, MD, USA.
Department of Kinesiology, University of Maryland, College Park, MD, USA; Program in Neuroscience and Cognitive Science, University of Maryland, College Park, MD, USA.
Exp Gerontol. 2022 Nov;169:111973. doi: 10.1016/j.exger.2022.111973. Epub 2022 Oct 4.
Biological aging is accompanied by a chronic pro-inflammatory state that may facilitate losses in hippocampal-dependent mnemonic discrimination. Aerobic exercise training promotes adaptations that include improved immune competency, higher cardiorespiratory fitness, and maintenance of hippocampal function. However, it is poorly understood whether, in active older adults, baseline immune cell profiles and cardiorespiratory fitness are possible mechanisms that facilitate the long-term benefits to hippocampal dependent mnemonic discrimination performance. This within-subjects study with counterbalanced conditions aimed to investigate whether baseline monocyte polarization and cardiorespiratory fitness influenced performance in the mnemonic similarity task (MST) and related Lure Discrimination Index (LDI) score after an acute bout of exercise. Twenty-one active older adults (M = 68 ± 5 yrs) underwent baseline testing in which blood samples were collected and cardiorespiratory fitness measured. Participants then returned and completed a seated rest or moderate intensity aerobic exercise condition in which the MST was proctored prior to and 5 min after each condition. A linear mixed effects model was used in which Participant ID was a random effect and Condition (rest v. exercise), Time (pre- v post-), and order were fixed main effects. Simple linear regression models were used to determine the variance accounted for by monocyte phenotypes and cardiorespiratory fitness for LDI scores post-condition. Post-rest LDI scores were significantly lower than post-exercise LDI scores (t(20) = -2.65, p < 0.02, d = -0.57). Intermediate monocytes were significant predictors of the change in pre- to post-exercise LDI scores (F(1, 19) = 6.03, p = 0.024, R = 0.24) and cardiorespiratory fitness was a significant predictor of the difference between post-condition LDI scores (F(1, 19) = 6.71, p = 0.018, R = 0.26). Our results suggest baseline cardiorespiratory fitness and intermediate monocytes may relate to the integrity of hippocampal-dependent mnemonic discrimination performance, and possibly the degree of responsiveness to aerobic exercise interventions.
生物衰老伴随着慢性促炎状态，可能促进海马依赖性记忆辨别力的丧失。有氧运动训练促进适应，包括提高免疫能力、更高的心肺健康水平和维持海马功能。然而，在活跃的老年人中，基础免疫细胞特征和心肺健康是否是促进海马依赖记忆辨别力表现的长期获益的可能机制尚不清楚。这项采用对照条件的个体内研究旨在探讨基础单核细胞极化和心肺健康是否影响记忆相似性任务 (MST) 的表现以及相关诱饵辨别指数 (LDI) 分数，这些分数是在一次急性运动后得出的。21 名活跃的老年人 (M=68±5 岁) 进行了基线测试，其中采集了血液样本并测量了心肺健康。然后，参与者返回并完成了坐姿休息或中等强度有氧运动，在每个条件之前和之后 5 分钟进行 MST 监测。使用线性混合效应模型，参与者 ID 是随机效应，条件 (休息 v. 运动)、时间 (前 v. 后) 和顺序是固定的主要效应。简单线性回归模型用于确定单核细胞表型和心肺健康对条件后 LDI 分数的方差解释。休息后的 LDI 分数明显低于运动后的 LDI 分数 (t(20)=-2.65，p<0.02，d=-0.57)。中间单核细胞是运动前后 LDI 分数变化的显著预测因子 (F(1,19)=6.03，p=0.024，R=0.24)，心肺健康是条件后 LDI 分数差异的显著预测因子 (F(1,19)=6.71，p=0.018，R=0.26)。我们的结果表明，基础心肺健康和中间单核细胞可能与海马依赖性记忆辨别力的完整性有关，可能与对有氧运动干预的反应程度有关。
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