Posgrado en Ciencias de la Salud (PCS), Universidad de Sonora, Hermosillo, Sonora, Mexico.
Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, USA.
J Nutr. 2020 Jun 1;150(6):1644-1651. doi: 10.1093/jn/nxaa048.
Retinol isotope dilution (RID) and model-based compartmental analysis are recognized techniques for assessing vitamin A (VA) status. Recent studies have shown that RID predictions of VA total body stores (TBS) can be improved by using modeling and that VA kinetics and TBS in children can be effectively studied by applying population modeling ("super-child" approach) to a composite data set.
The objectives were to model whole-body retinol kinetics and predict VA TBS in a group of Mexican preschoolers using the super-child approach and to use model predictions of RID coefficients to estimate TBS by RID in individuals.
Twenty-four healthy Mexican children (aged 3-6 y) received an oral dose (2.96 μmol) of [13C10]retinyl acetate in corn oil. Blood samples were collected from 8 h to 21 d after dosing, with each child sampled at 4 d and at 1 other time. Composite data for plasma labeled retinol compared with time were analyzed using a 6-component model to obtain group retinol kinetic parameters and pool sizes. Model-predicted TBS was compared with mean RID predictions at 4 d; RID estimates at 4 d were compared with those calculated at 7-21 d.
Model-predicted TBS was 1097 μmol, equivalent to ∼2.4 y-worth of VA; using model-derived coefficients, group mean RID-predicted TBS was 1096 μmol (IQR: 836-1492 μmol). TBS at 4 d compared with a later time was similar (P = 0.33). The model predicted that retinol spent 1.5 h in plasma during each transit and recycled to plasma 13 times before utilization.
The super-child modeling approach provides information on whole-body VA kinetics and can be used with RID to estimate TBS at any time between 4 and 21 d postdose. The high TBS predicted for these children suggests positive VA balance, likely due to large-dose VA supplements, and warrants further investigation.
视黄醇同位素稀释（RID）和基于模型的房室分析是评估维生素 A（VA）状态的公认技术。最近的研究表明，通过建模可以提高 RID 对 VA 全身总储存量（TBS）的预测，并且可以通过将群体模型（“超级儿童”方法）应用于综合数据集来有效地研究儿童的 VA 动力学和 TBS。
本研究的目的是使用超级儿童方法对一组墨西哥学龄前儿童进行全身视黄醇动力学建模，并预测 VA TBS，以及使用 RID 系数的模型预测来通过 RID 估计个体的 TBS。
24 名健康的墨西哥儿童（3-6 岁）口服（2.96 μmol）[13C10]视黄基乙酸酯在玉米油中。在给药后 8 小时至 21 天内采集血样，每个儿童在 4 天和另一个时间点进行采样。使用 6 分量模型分析血浆标记视黄醇与时间的复合数据，以获得组视黄醇动力学参数和池大小。模型预测的 TBS 与 4 天时的 RID 预测值进行比较；4 天时的 RID 估计值与 7-21 天时的计算值进行比较。
模型预测的 TBS 为 1097 μmol，相当于 2.4 年的 VA；使用模型衍生的系数，组平均 RID 预测的 TBS 为 1096 μmol（IQR：836-1492 μmol）。4 天时的 TBS 与以后的时间相似（P=0.33）。模型预测视黄醇在每次转运过程中在血浆中停留 1.5 小时，并在利用前在血浆中循环 13 次。
超级儿童建模方法提供了全身 VA 动力学的信息，并且可以与 RID 一起用于在给药后 4 至 21 天之间的任何时间估计 TBS。这些儿童预测的高 TBS 表明 VA 处于正平衡状态，这可能是由于大剂量 VA 补充剂，值得进一步研究。
