AUTHOR=Lian Teng-Hong , Guo Peng , Zuo Li-Jun , Hu Yang , Yu Shu-Yang , Yu Qiu-Jin , Jin Zhao , Wang Rui-Dan , Li Li-Xia , Zhang Wei 

TITLE=Tremor-Dominant in Parkinson Disease: The Relevance to Iron Metabolism and Inflammation

JOURNAL=Frontiers in Neuroscience

VOLUME=13

YEAR=2019

URL=https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2019.00255

DOI=10.3389/fnins.2019.00255

ISSN=1662-453X

ABSTRACT=<p><bold>Background:</bold> Tremor is one of the most predominant symptoms of patients with Parkinson disease (PD), but the underlying mechanisms for tremor relating to iron and its metabolism-related proteins and the inflammatory factors in cerebrospinal fluid (CSF) and serum have not been fully elucidated.</p><p><bold>Methods:</bold> A total of 135 PD patients were divided into a tremor-dominant (PD-TD) group (<italic>N</italic> = 74) and a postural instability and gait difficulty-dominant (PD-PIGD) group (<italic>N</italic> = 39) based on the ratio of mean tremor score to the mean bradykinesia/rigid score of the Unified Parkinson’s Disease Rating Scale (UPDRS) III. Age and sex-matched healthy controls were recruited (<italic>N</italic> = 35). Demographic variables were evaluated; iron and its metabolism-related proteins and the inflammatory mediators in both CSF and serum were measured in these groups. The relevance of iron metabolism, inflammation and PD-TD were analyzed.</p><p><bold>Results:</bold> (1) The PD-TD group had significantly decreased <sc>L</sc>-ferritin, increased iron levels in CSF and increased ferritin levels in the serum compared with the PD-PIGD and control groups (<italic>P</italic> &lt; 0.05). (2) The PD-TD group had significantly enhanced IL-6 levels in both CSF and serum compared with the PD-PIGD and control groups (<italic>P</italic> &lt; 0.05). (3) In CSF, the IL-6 level was increased as the iron level was elevated in the PD-TD group (<italic>r</italic> = 0.308, <italic>P</italic> = 0.022). In serum, the IL-6 level was increased as the ferritin level was elevated in the PD-TD group (<italic>r</italic> = 0.410, <italic>P</italic> = 0.004).</p><p><bold>Conclusion:</bold> The interplay between disturbed iron metabolism and relevant inflammation might modulate clinical phenotypes of PD.</p>