Is C-reactive protein level a marker of advanced motor and neuropsychiatric complications in Parkinson’s disease?

Abstract

C-reactive protein (CRP) is a plasma protein involved in inflammation. While its levels have been associated with stroke, cognitive impairment and depression, the association with clinical characteristics of Parkinson's disease (PD) is unknown. A total of 73 consecutive patients with PD (46 males, age 68.8 ± 11.5 years) were evaluated regarding motor as well as cognitive and psychiatric features of PD. Plasma CRP levels were determined and tests for associations with disease parameters were performed. The average level of CRP was 3.9 ± 4.1 μmol/L, and 45.2% of the patients (n = 33) had a level above 3.0 μmol/L. Patients in the high CRP group tended to be older (71.4 ± 9.2 vs. 66.7 ± 12.9 years; p = 0.08) and coronary artery disease (CAD) was more common (36 vs. 10%, p < 0.05) in the high CRP group, but no differences were found between the groups regarding gender, disease duration, levodopa dose, motor scores or most of the neuropsychiatric complications such as severity of depression, psychosis, dementia, cognitive decline or frontal lobe dysfunction. Reported depression (at present or in the past) was more common in the high CRP group (54.5 vs. 25%, p = 0.01). CRP levels in patients with PD are associated with a higher prevalence of CAD, but are not associated with PD duration or severity, or with neuropsychiatric complications other than reported depression.

Depression and Cognitive Impairment in Parkinson's Disease: A Role for Inflammation and Immunomodulation?

“…Here, they also failed to demonstrate any associations between CRP levels and motor as well as cognitive and psychiatric features such as severity of depression, psychosis, dementia, cognitive decline or frontal lobe dysfunction. CRP is an acute-phase protein whose plasma levels increase during inflammatory states [46]. In line with these findings, another study has shown the lack of significant correlation between IL-6 or CRP blood levels and any of the NMS scales, including depressive and anxiety symptom assessment [5].…”

“…Also, sIL-2-R levels were able to predict FACIT-F and HAD scores even after the effects of age, gender, antiparkinsonian medications and severity of motor symptoms were controlled for [5]. One other study demonstrated that the presence of current or prior depression was more common in those PD patients who had higher CRP plasma levels [46]. …”

“…They could not show any correlation between a patients' clinical state (both motor and neuropsychologic, as expressed by MMSE) and the inflammatory molecules assessed (IL-6, acute-phase proteins and factors of the complement system) [45]. A separate study comprising a cohort of 73 patients with PD was conducted with a similar purpose [46]. Here, they also failed to demonstrate any associations between CRP levels and motor as well as cognitive and psychiatric features such as severity of depression, psychosis, dementia, cognitive decline or frontal lobe dysfunction.…”

Peripheral Administration of the Selective Inhibitor of Soluble Tumor Necrosis Factor (TNF) XPro®1595 Attenuates Nigral Cell Loss and Glial Activation in 6-OHDA Hemiparkinsonian Rats

“…The significance of being able to block inflammation at any point during the disease might have benefits for non-motor symptoms [13, 39]. Subsequently, others have shown that TNF [16] and c-reactive protein (CRP), classic companion biomarkers of inflammation, were correlated with fatigue [15], depression [40], cognition [41], and hallucination [42] in PD patients and plasma solTNF receptors were correlated with cognitive impairment in PD patients [17]. Elevated CRP has also been observed to correlate with motor dysfunction in PD patients [43–46].…”

Proteomics and metabolomics in ageing research: from biomarkers to systems biology

“…As such, biomarkers could predict risk of future age-related morbidity and mortality. However, the search for these biomarkers has often failed [18,19,37]. For example, telomere length has been a highly studied ‘biomarker’ of ageing, as they shorten as individuals grow older, yet telomeres have failed as a predictor of mortality [18,19].…”