Section of Metabolic Diseases, Beatrix Children's Hospital, University Medical Centre of Groningen, University of Groningen, Groningen, The Netherlands.
Ann Nutr Metab. 2011;58(2):94-100. doi: 10.1159/000324924. Epub 2011 Apr 8.
BACKGROUND/AIMS: In patients with phenylketonuria (PKU), target ranges of blood phenylalanine (Phe) concentrations have been tightened in order to improve long-term outcomes. We investigated day-to-day and week-to-week variations in blood Phe concentration and the effect of an additional Phe load.
We performed a longitudinal study in 6 adult PKU patients. The study was divided in five 7-day periods: 1 period without any intervention (period I) and 4 periods with a Phe load on day 3 equivalent to 100% (periods II and III) and to 200% (periods IV and V) of each patient's individual daily Phe intake. Phe loading was given as encapsulated L-Phe. Blood spots to measure blood Phe concentration were taken each morning before breakfast in all periods.
Day-to-day and week-to-week blood Phe concentrations varied considerably with and without intervention in Phe intake. Equal loads of Phe did not result in comparable effects in blood Phe concentrations in all patients. In periods II-IV, mean blood Phe concentrations of days 1-3 (pre-load) were not significantly different from days 4-7 (post-load). The 200% load resulted in a significantly larger variation.
These results showed that patients with well-controlled PKU can incidentally tolerate 100% - and in some cases 200% - of their normal daily Phe intake.
背景/目的：在苯丙酮尿症（PKU）患者中，为了改善长期预后，已将血液苯丙氨酸（Phe）浓度的目标范围收紧。我们研究了血液 Phe 浓度的日常和每周变化，以及额外 Phe 负荷的影响。
我们对 6 名成年 PKU 患者进行了一项纵向研究。该研究分为五个 7 天的周期：一个没有任何干预的周期（I 期）和四个 Phe 负荷周期，相当于每个患者个体日常 Phe 摄入量的 100%（周期 II 和 III）和 200%（周期 IV 和 V）。Phe 负荷以包裹的 L-Phe 形式给予。所有周期中，每天早餐前采集血样点以测量血液 Phe 浓度。
无论是否干预 Phe 摄入，日常和每周的血液 Phe 浓度都有很大差异。等量的 Phe 负荷在所有患者中并未导致血液 Phe 浓度产生可比的影响。在 II-IV 期，负荷前（预负荷）的第 1-3 天的平均血 Phe 浓度与负荷后（后负荷）的第 4-7 天无显著差异。200%的负荷导致了更大的变化。
这些结果表明，病情控制良好的 PKU 患者偶然可以耐受 100% - 在某些情况下甚至可以耐受 200% - 的正常日常 Phe 摄入量。
