Monoamine Levels and Parkinson's Disease Progression: Evidence From a High-Performance Liquid Chromatography Study.

Patsorn Wichit,Roongroj Bhidayasiri,Sekh Thanprasertsuk,Saknan Bongsebandhu-Phubhakdi,Onanong Phokaewvarangkul

doi:10.3389/fnins.2021.605887

Abstract

Parkinson’s disease (PD) is associated with dysfunction of monoamine neurotransmitter systems. We investigated changes in the levels of monoamine and their metabolites in PD patients, together with their association to clinical profiles. PD patients and age-matched control subjects (n = 40 per group) were enrolled. Using high-performance liquid chromatography (HPLC) with an electrochemical detector, levels of monoamines (dopamine, DA; norepinephrine, NE; epinephrine, EPI; and serotonin, 5-HT) were measured in plasma, while the metabolites (homovanillic acid, HVA; vanillylmandelic acid, VMA; and 5-hydroxyindoleacetic acid, 5-HIAA) were measured in urine. Plasma DA level was not significantly different between PD and control groups. PD patients had significantly higher plasma NE but lower EPI and 5-HT levels. PD patients had a significantly higher HVA/DA ratio and lower VMA/NE ratio than control subjects, while the 5-HIAA/5-HT ratio was not different between the groups. Regarding the association between monoamine levels and clinical profiles, the DA level had a negative relationship with disease duration and the 5-HT level had a negative relationship with severity of motor impairment. These findings emphasized the involvements of several neurotransmission systems and their association with clinical profiles in PD patients, demonstrated by quantification of monoamine levels in peripheral body fluids. This could benefit appropriate pharmacological treatment planning in respect of monoamine changes and might also help predict subsequent clinical symptoms.

Highlights

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by motor impairments including bradykinesia, rigidity, rest tremor, and postural instability, combined with a variety of non-motor symptoms (Przedborski, 2017)
This study demonstrated the alteration in the levels of DA and other monoamine neurotransmitters in peripheral body fluids by quantifying plasma monoamine levels and their urinary metabolites in PD patients
As there have been few reports determining these chemicals in plasma and urine of PD patients, FIGURE 2 | Comparisons of urinary homovanillic acid (HVA) (A), vanillylmandelic acid (VMA) (B), and 5-hydroxyindoleacetic acid (5-HIAA) (C) levels and high-performance liquid chromatography (HPLC) chromatograms between control subjects and PD patients

Summary

Introduction

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by motor impairments including bradykinesia, rigidity, rest tremor, and postural instability, combined with a variety of non-motor symptoms (Przedborski, 2017). Hallmark pathologies of PD are Lewy body deposition and progressive deterioration of dopaminergic neurons in substantia nigra, leading to depletion of central dopamine (DA) level (Braak et al, 2003). Neurologists usually diagnose PD based on clinical assessment and dopaminergic medication responsiveness. Apart from abnormality of DA, neuroimaging and postmortem brain tissue studies have demonstrated imbalances of other monoamine neurotransmitters in PD including norepinephrine (NE), epinephrine (EPI), and serotonin (5HT) (Barone, 2010). There is lack of information on the alteration of monoamine levels measuring in peripheral body fluids in different stages of PD. Many reports showed contradictory information regarding the association between monoamine dysfunctions and clinical profiles of PD such as age, gender, medications, disease duration, and severity (Lunardi et al, 2009; Olivola et al, 2014; Kaasinen and Vahlberg, 2017)

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