The present study was performed to examine if catechol oxidation is higher in brains from patients with Parkinson’s disease compared to age-matched controls, and if catechol oxidation increases with age. Brain tissue from Parkinson patients and age-matched controls was examined for oxidation of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and 3,4-dihydroxyphenylalanine (DOPA) to corresponding quinones, by measurement of 5-S-cysteinyl-dopamine, 5-S-cysteinyl-DOPAC and 5-S-cysteinyl-DOPA. The cysteinyl catechols are assumed to be biomarkers for DA, DOPAC and DOPA autoxidation and part of the biosynthetic pathway of neuromelanin. The concentrations of the 5-S-cysteinyl catechols were lower, whereas the 5-S-cysteinyl-DA/DA and 5-S-cysteinyl-DOPAC/DOPAC ratios tended to be higher in the Parkinson group compared to controls, which was interpreted as a higher degree of oxidation. High 5-S-cysteinyl-DA/DA ratios were found in the substantia nigra of a sub-population of the Parkinson group. Based on 5-S-cysteinyl-DA/DA ratios, dopamine oxidation was found to increase statistically significantly with age in the caudate nucleus, and non-significantly in the substantia nigra. In conclusion, the occurrence of 5-S-cysteinyl-DA, 5-S-cysteinyl-DOPAC and 5-S-cysteinyl-DOPA was demonstrated in dopaminergic brain areas of humans, a tendency for higher oxidation of DA in the Parkinson group compared to controls was observed as well as a statistically significant increase in DA oxidation with age. Possibly, autoxidation of DA and other catechols are involved in both normal and pathological ageing of the brain. This study confirms one earlier but small study, as well as complements one study on non-PD cases and one study on both PD cases and controls on NM bound or integrated markers or catechols.

本研究的目的是检查帕金森病患者大脑中的儿茶酚氧化是否比年龄匹配的对照组更高，以及儿茶酚氧化是否随着年龄的增长而增加。通过测量 5-S-半胱氨酰多巴胺，检查帕金森病患者和年龄匹配对照的脑组织中多巴胺、3,4-二羟基苯乙酸 (DOPAC) 和 3,4-二羟基苯丙氨酸 (DOPA) 氧化成相应的醌， 5- S-半胱氨酰-DOPAC和5- S-半胱氨酰-DOPA。半胱氨酰儿茶酚被认为是 DA、DOPAC 和 DOPA 自动氧化的生物标志物，也是神经黑色素生物合成途径的一部分。与对照组相比，帕金森组中 5- S-半胱氨酰儿茶酚的浓度较低，而 5- S-半胱氨酰-DA/DA 和 5- S-半胱氨酰-DOPAC/DOPAC 比率往往较高，这被解释为因为氧化程度较高。在帕金森病组亚群的黑质中发现了较高的 5- S-半胱氨酰-DA/DA 比率。根据 5- S-半胱氨酰-DA/DA 比率，发现尾状核中的多巴胺氧化随着年龄的增长而显着增加，而黑质中的增加不显着。总之，在人类多巴胺能脑区中发现了5- S-半胱氨酰-DA、5- S-半胱氨酰-DOPAC和5- S-半胱氨酰-DOPA的存在，与帕金森组相比，帕金森组中DA有更高氧化的趋势观察到与对照组相比，随着年龄的增长，DA 氧化有统计学上显着的增加。DA 和其他儿茶酚的自氧化可能与大脑的正常和病理性衰老有关。这项研究证实了一项较早但规模较小的研究，并补充了一项针对非 PD 病例的研究以及一项针对 PD 病例和 NM 结合或整合标记物或儿茶酚对照的研究。