Department of Clinical Biochemistry and Metabolic Medicine, Liverpool Clinical Laboratories, Royal Liverpool University Hospitals Trust, Liverpool, L7 8XP, UK.
Musculoskeletal Biology I, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool Health Partners, Liverpool, UK.
Metabolomics. 2019 Apr 29;15(5):68. doi: 10.1007/s11306-019-1531-4.
Nitisinone induced hypertyrosinaemia is a concern in patients with Alkaptonuria (AKU). It has been suggested that this may alter neurotransmitter metabolism, specifically dopamine and serotonin. Herein mass spectrometry imaging (MSI) is used for the direct measurement of 2,4-diphenyl-pyranylium tetrafluoroborate (DPP-TFB) derivatives of monoamine neurotransmitters in brain tissue from a murine model of AKU following treatment with nitisinone.
Metabolite changes were assessed using MSI on DPP-TFB derivatised fresh frozen tissue sections directing analysis towards primary amine neurotransmitters. Matched tail bleed plasma samples were analysed using LC-MS/MS. Eighteen BALB/c mice were included in this study: HGD (n = 6, treated with nitisinone-4 mg/L, in drinking water); HGD (n = 6, no treatment) and HGD (n = 6, no treatment).
Ion intensity and distribution of DPP-TFB derivatives in brain tissue for dopamine, 3-methoxytyramine, noradrenaline, tryptophan, serotonin, and glutamate were not significantly different following treatment with nitisinone in HGD mice, and no significant differences were observed between HGD and HGD mice that received no treatment. Tyrosine (10-fold in both comparisons, p = 0.003; [BALB/c HGD (n = 6) and BALB/c HGD (n = 6) (no treatment) vs. BALB/c HGD (n = 6, treated)] and tyramine (25-fold, p = 0.02; 32-fold, p = 0.02) increased significantly following treatment with nitisinone. Plasma tyrosine and homogentisic acid increased (ninefold, p = < 0.0001) and decreased (ninefold, p = 0.004), respectively in HGD mice treated with nitisinone.
Monoamine neurotransmitters in brain tissue from a murine model of AKU did not change following treatment with nitisinone. These findings have significant implications for patients with AKU as they suggest monoamine neurotransmitters are not altered following treatment with nitisinone.
硝替卡朋诱导的高酪氨酸血症是尿黑酸症（AKU）患者的一个关注点。据报道，这可能会改变神经递质代谢，特别是多巴胺和 5-羟色胺。在此，采用质谱成像（MSI）技术对 AKU 小鼠模型给予硝替卡朋治疗后，脑组织中 2,4-二苯基-吡喃鎓四氟硼酸盐（DPP-TFB）衍生的单胺神经递质进行直接测量。
采用 MSI 对 DPP-TFB 衍生的新鲜冷冻组织切片进行代谢物变化评估，直接分析主要胺类神经递质。匹配的尾静脉血样采用 LC-MS/MS 分析。本研究纳入 18 只 BALB/c 小鼠：HGD（n=6，用 4mg/L 硝替卡朋治疗，在饮用水中）；HGD（n=6，未治疗）和 HGD（n=6，未治疗）。
HGD 小鼠给予硝替卡朋治疗后，DPP-TFB 衍生物在脑组织中多巴胺、3-甲氧基酪胺、去甲肾上腺素、色氨酸、5-羟色胺和谷氨酸的离子强度和分布无显著差异，HGD 小鼠与未治疗的 HGD 小鼠之间也未观察到显著差异。酪氨酸（两种比较均增加 10 倍，p=0.003；[BALB/c HGD（n=6）和 BALB/c HGD（n=6）（未治疗）与 BALB/c HGD（n=6，治疗）]和酪胺（增加 25 倍，p=0.02；增加 32 倍，p=0.02）在给予硝替卡朋治疗后显著增加。给予硝替卡朋的 HGD 小鼠血浆酪氨酸和高香草酸分别增加（增加 9 倍，p<0.0001）和减少（减少 9 倍，p=0.004）。
AKU 小鼠模型脑组织中单胺神经递质在给予硝替卡朋治疗后未发生变化。这些发现对 AKU 患者具有重要意义，因为它们表明给予硝替卡朋治疗后单胺神经递质未发生改变。
