title: Plasma Cystatin C and High-Density Lipoprotein Are Important Biomarkers of Alzheimer's Disease and Vascular Dementia: A Cross-Sectional Study.
abstract: Objectives: Cystatin C (Cys C) and high-density lipoprotein (HDL) play critical roles in neurodegenerative diseases, such as dementia, Alzheimer's disease (AD) and vascular dementia (VaD). However, whether they can be used as reliable biomarkers to distinguish patients with dementia from healthy subjects and to determine disease severity remain largely unknown.Methods: We conducted a cross-sectional study to determine plasma Cys C and HDL levels of 88 patients with dementia (43 AD patients, 45 VaD patients) and 45 healthy age-matched controls. The severity of dementia was determined based on the Schwab and England Activities of Daily Living (ADL) Scale, the Mini-mental State Examination (MMSE), the Global Deterioration Scale (GDS), the Lawton Instrumental ADL (IADL) Scale, and the Hachinski Ischemia Scale (Hachinski). Receiver operating characteristic (ROC) curves were calculated to determine the diagnostic accuracy of Cys C and HDL levels in distinguishing patients with dementia from healthy subjects.Results: We found that plasma Cys C levels were higher, but HDL levels were lower in AD and VaD patients respectively, compared to healthy control subjects. Yet, Cys C levels were highest among patients with VaD. Interestingly, plasma Cys C levels were significantly correlated with IADL Scale scores. In addition, the ROC curves for Cys C (area under the curve, AUC 0.816 for AD, AUC 0.841 for VaD) and HDL (AUC 0.800 for AD, AUC 0.731 for VaD) exhibited potential diagnostic value in distinguishing AD/VaD patients from healthy subjects. While the ROC curve for the combination of Cys C and HDL (AUC 0.873 for AD, AUC 0.897 for VaD) showed higher diagnostic accuracy in distinguishing AD/VaD patients from healthy subjects than the separate curves for each parameter.Conclusions: Our findings suggest that the inflammatory mediators Cys C and HDL may play important roles in the pathogenesis of dementia, and plasma Cys C and HDL levels may be useful screening tools for differentiating AD/VaD patients from healthy subjects.
  
  
  CONCLUSIONS
  Plasma Cys C levels were higher in patients with AD/VaD than in healthy subjects.Plasma HDL levels were lower in patients with AD/VaD than in healthy subjects.Plasma Cys C levels were significantly correlated with dementia.The ROC curve for the combination of Cys C and HDL showed potential diagnostic value in distinguishing AD/VaD from healthy subjects.
authors.affiliation: Departments of Neurology, The Third Affiliated Hospital of Sun Yat-Sen University Guangzhou, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.affiliation: Departments of Neurology, The Third Affiliated Hospital of Sun Yat-Sen University Guangzhou, China.
authors.forename: Zhaoyu
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Departments of Emergency, The Third Affiliated Hospital of Sun Yat-Sen University Guangzhou, China.
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Fu
authors.affiliation: Departments of Neurology, The Third Affiliated Hospital of Sun Yat-Sen University Guangzhou, China.
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Wei
authors.affiliation: Departments of Neurology, The Third Affiliated Hospital of Sun Yat-Sen University Guangzhou, China.
authors.forename: Jinchi
authors.initials: J
authors.lastname: Liao
authors.affiliation: Departments of Neurology, The Third Affiliated Hospital of Sun Yat-Sen University Guangzhou, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Liu
authors.affiliation: Departments of Radiology, The Third Affiliated Hospital of Sun Yat-Sen University Guangzhou, China.
authors.forename: Bingjun
authors.initials: B
authors.lastname: He
authors.affiliation: Department of Neurology, Nanfang Hospital, Southern Medical University Guangzhou, China.
authors.forename: Yunqi
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Departments of Neurology, The Third Affiliated Hospital of Sun Yat-Sen University Guangzhou, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zou
authors.affiliation: Departments of Emergency, The Third Affiliated Hospital of Sun Yat-Sen University Guangzhou, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Yang
authors.affiliation: Departments of Neurology, The Third Affiliated Hospital of Sun Yat-Sen University Guangzhou, China.
authors.forename: Ruihui
authors.initials: R
authors.lastname: Weng
authors.affiliation: Departments of Neurology, Zhujiang Hospital, Southern Medical University Guangzhou, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Tan
authors.affiliation: Department of Pharmacology and Neuroscience, University of North Texas Health Science Center Fort Worth, TX, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: McElroy
authors.affiliation: Department of Pharmacology and Neuroscience, University of North Texas Health Science Center Fort Worth, TX, USA.
authors.forename: Kunlin
authors.initials: K
authors.lastname: Jin
authors.affiliation: Departments of Neurology, The Third Affiliated Hospital of Sun Yat-Sen UniversityGuangzhou, China; Guangdong Province Key Laboratory of Brain Function and DiseaseGuangzhou, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
keywords: Alzheimer’s disease; cystatin C; dementia; high-density lipoprotein; vascular dementia