Abstract：
Monocytes are innate immune cells that are continuously produced in bone marrow which enter and circulate the vasculature. In response to nutrient scarcity, monocytes migrate back to bone marrow where upon refeeding they are re-released back into the bloodstream to replenish the circulation. In humans, the variability in monocyte behavior in response to fasting and refeeding has not been characterized. To investigate monocyte dynamics in humans we measured blood monocyte fluctuations in 354 clinically healthy individuals after a 12-hour overnight fast and at 3- and 6-hours after consuming a mixed macronutrient challenge meal. Using cluster analysis, we identified three distinct monocyte behaviors. Group 1 was characterized by relatively low fasting monocyte counts that markedly increased after consuming the test meal. Group 2 was characterized by relatively high fasting monocyte counts which decreased after meal consumption. Group 3, like Group 1, was characterized by lower fasting monocyte counts but increased to a lesser extent after consuming the meal. While monocyte fluctuations observed in Groups 1 and 3 align with the current paradigm of monocyte dynamics in response to fasting and refeeding, the atypical dynamic observed in Group 2 does not. While generally younger in age, Group 2 subjects had lower whole-body carbohydrate oxidation rates, lower HDL-cholesterol levels, delayed postprandial declines in salivary cortisol, and reduced postprandial peripheral microvascular endothelial function. These unique characteristics were not explained by group differences in age, sex, or BMI. Taken together these results highlight distinct patterns of monocyte responsiveness to natural fluctuations in dietary fuel availability.
摘要：
单核细胞是在进入和循环脉管系统的骨髓中连续产生的先天免疫细胞。为了应对营养短缺，单核细胞迁移回骨髓，在那里重新喂食后，它们被重新释放回血液以补充循环。在人类中,单核细胞响应禁食和再摄食的行为的变异性尚未得到表征。为了研究人类的单核细胞动力学，我们测量了354名临床健康个体在禁食12小时后以及在食用混合常量营养素挑战餐后3和6小时的血液单核细胞波动。使用聚类分析，我们确定了三种不同的单核细胞行为。第1组的特征在于相对低的空腹单核细胞计数,其在消耗测试餐后显著增加。第2组的特征在于相对较高的空腹单核细胞计数,其在进餐后减少。与第1组一样，第3组的特征是空腹单核细胞计数较低，但在进食后增加的程度较小。虽然在第1组和第3组中观察到的单核细胞波动与当前的单核细胞动力学范式一致，以响应禁食和再喂食，在第2组中观察到的非典型动态没有。虽然年龄通常较小，第2组受试者的全身碳水化合物氧化率较低，降低HDL-胆固醇水平，唾液皮质醇延迟餐后下降，餐后外周血微血管内皮功能降低。这些独特的特征不能用年龄的群体差异来解释，性别,或BMI。总之，这些结果突出了单核细胞对饮食燃料可用性自然波动的反应性的不同模式。
