The role of inflammatory cytokines in cognition and other non-motor symptoms of Parkinson's disease.
BACKGROUND
Parkinson's disease (PD) affects patients' lives with more than just physical impairment. Many of the non-motor aspects of PD, such as cognitive impairment, depression, and sleep disturbances, are common and are associated with a variety of poor outcomes. However, at present, the pathophysiology and clinical management of these symptoms are poorly understood.


OBJECTIVE
The authors sought to determine the associations between various illness-associated cytokines, cortisol, and the non-motor symptoms of PD.


METHODS
The authors examined a panel of cytokines (IL-1β, IL-6, IL-10, TNF-α) and cortisol in a cohort of 52 PD patients with depression.


RESULTS
There were a number of significant correlations between the non-motor symptoms and TNF-α. Specifically, the authors found that TNF-α (but not IL-1β, IL-6, IL-10, or cortisol) was significantly correlated with measures of cognition, depression, and disability. In regression analyses accounting for all variables, TNF-α was consistently significant in explaining variance in cognition, depression, sleep, and disability.


CONCLUSIONS
These data are consistent with a growing body of literature that implicates inflammatory cytokines in neural and behavioral processes and further suggests that TNF-α may be involved in the production and/or maintenance of non-motor symptoms in PD.
Psychiatry & Neurology, Robert Wood Johnson Medical School, D207A, 671 Hoes Lane, Piscataway, NJ 08854, USA. menza@umdnj.edu
Matthew
M
Menza
Roseanne Defronzo
RD
Dobkin
Humberto
H
Marin
Margery H
MH
Mark
Michael
M
Gara
Karina
K
Bienfait
Allison
A
Dicke
Alex
A
Kusnekov
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003072:Cognition Disorders / Q000097:blood / Q000503:physiopathology*; D016207:Cytokines / Q000097:blood*; D003863:Depression / Q000097:blood / Q000503:physiopathology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D007375:Interleukin-1 / Q000097:blood; D016753:Interleukin-10 / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D007406:Interview, Psychological; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000097:blood / Q000503:physiopathology*; D011569:Psychiatric Status Rating Scales; D011788:Quality of Life; D012044:Regression Analysis; D012307:Risk Factors; D012893:Sleep Wake Disorders / Q000097:blood / Q000503:physiopathology*; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
D016207:Cytokines; D007375:Interleukin-1; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D006854:Hydrocortisone