Tion process [11]. Actually, missense and multiplication mutations in SNCA are associated with familial PD and the formation of LBs and LNs [12]. The central nervous system has been proposed as the source of a-synuclein, and neurons are thought to release Title Loaded From File a-synuclein which is able to enter the cerebrospinal fluid (CSF) [13,14], and a-synuclein has also been detected in blood plasma [13]. Recent studies have confirmed the presence of a-synuclein in such extracellular fluids [15?9]. Although a-synuclein in the CSF has been proposed as a biomarker of PD, relatively few studies have addressed the issue of what levels of a-synuclein are present in human plasma [16?19]. Data from these studies have been difficult to interpret, suggesting that more sensitive, standardized, and well-characterized assays of larger cohorts are required, as pointed out previously by Mollenhauer and colleagues [20].Levels of a-Synuclein in PD BloodIt has been hypothesized that early aggregates or “soluble oligomers” of synuclein are the pathogenic species that lead to neuronal death and neurodegeneration rather than the insoluble late aggregates “amyloid fibril” [21,22]. In this sense, increased levels of soluble a-synuclein oligomers have been identified in the plasma tissue and post mortem brain homogenates of PD patients [23?5]. In the present study we measured both the total and oligomeric forms of a-synuclein in blood plasma of patients with iPD and LRRK2 forms of PD with a view to determine if differences exist between these two groups and healthy controls.Genetic AnalysisDNA was extracted from peripheral blood using standard laboratory procedures. All patients and control individuals were screened for both 4321C.G (R1441G) and 6055G.A (G2019S) mutations in the LRRK2 gene (these being the most prevalent LRRK2 mutations). Single nucleotide polymorphism Title Loaded From File genotyping was also performed using TaqMan chemistry on an ABI7300 instrument (Applied Biosystems, Foster City, CA) according to manufacturer’s instructions.Measurements of Total a-synuclein Levels in Plasma Materials and Methods SubjectsPatients with PD were recruited from the Movement Disorders Unit of the Hospital Donostia (MDUD, Hospital Universitario Donostia, San Sebastian, Spain). Healthy controls were recruited from among the spouses of patients in the MDUD. PD was diagnosed according to the Gelb criteria by neurologists specialized in movement disorders [26]. Patients underwent a physical examination and completed a clinical questionnaire to provide details of demographic and clinical features of their condition. The clinical severity of parkinsonism was assessed according to the Hoehn and Yahr (H Y) scale. All subjects provided their written informed consent to participate in the study, which was approved by the local Ethical Board of the Hospital (Hospital Universitario Donostia). Plasma total a-synuclein was measured using a sandwich ELISA assay as described previously [27], with some modifications aimed at improving sensitivity. Briefly, an anti-human a-synuclein monoclonal antibody 211 (mAb-211; Santa Cruz Biotechnology, USA) was used for capturing, and an anti-human a-synuclein polyclonal antibody (FL-140; Santa Cruz Biotechnology, USA) was used for antigen detection with a horseradish peroxidase (HRP)-linked chemiluminescence 18325633 assay. The ELISA plate (Nunc Maxisorb, NUNC, Denmark) was coated for overnight incubation at 4uC with 1 mg/ml of mAb-211 (50 ml/well) in 200 mM NaHCO3, pH 9.6, and then.Tion process [11]. Actually, missense and multiplication mutations in SNCA are associated with familial PD and the formation of LBs and LNs [12]. The central nervous system has been proposed as the source of a-synuclein, and neurons are thought to release a-synuclein which is able to enter the cerebrospinal fluid (CSF) [13,14], and a-synuclein has also been detected in blood plasma [13]. Recent studies have confirmed the presence of a-synuclein in such extracellular fluids [15?9]. Although a-synuclein in the CSF has been proposed as a biomarker of PD, relatively few studies have addressed the issue of what levels of a-synuclein are present in human plasma [16?19]. Data from these studies have been difficult to interpret, suggesting that more sensitive, standardized, and well-characterized assays of larger cohorts are required, as pointed out previously by Mollenhauer and colleagues [20].Levels of a-Synuclein in PD BloodIt has been hypothesized that early aggregates or “soluble oligomers” of synuclein are the pathogenic species that lead to neuronal death and neurodegeneration rather than the insoluble late aggregates “amyloid fibril” [21,22]. In this sense, increased levels of soluble a-synuclein oligomers have been identified in the plasma tissue and post mortem brain homogenates of PD patients [23?5]. In the present study we measured both the total and oligomeric forms of a-synuclein in blood plasma of patients with iPD and LRRK2 forms of PD with a view to determine if differences exist between these two groups and healthy controls.Genetic AnalysisDNA was extracted from peripheral blood using standard laboratory procedures. All patients and control individuals were screened for both 4321C.G (R1441G) and 6055G.A (G2019S) mutations in the LRRK2 gene (these being the most prevalent LRRK2 mutations). Single nucleotide polymorphism genotyping was also performed using TaqMan chemistry on an ABI7300 instrument (Applied Biosystems, Foster City, CA) according to manufacturer’s instructions.Measurements of Total a-synuclein Levels in Plasma Materials and Methods SubjectsPatients with PD were recruited from the Movement Disorders Unit of the Hospital Donostia (MDUD, Hospital Universitario Donostia, San Sebastian, Spain). Healthy controls were recruited from among the spouses of patients in the MDUD. PD was diagnosed according to the Gelb criteria by neurologists specialized in movement disorders [26]. Patients underwent a physical examination and completed a clinical questionnaire to provide details of demographic and clinical features of their condition. The clinical severity of parkinsonism was assessed according to the Hoehn and Yahr (H Y) scale. All subjects provided their written informed consent to participate in the study, which was approved by the local Ethical Board of the Hospital (Hospital Universitario Donostia). Plasma total a-synuclein was measured using a sandwich ELISA assay as described previously [27], with some modifications aimed at improving sensitivity. Briefly, an anti-human a-synuclein monoclonal antibody 211 (mAb-211; Santa Cruz Biotechnology, USA) was used for capturing, and an anti-human a-synuclein polyclonal antibody (FL-140; Santa Cruz Biotechnology, USA) was used for antigen detection with a horseradish peroxidase (HRP)-linked chemiluminescence 18325633 assay. The ELISA plate (Nunc Maxisorb, NUNC, Denmark) was coated for overnight incubation at 4uC with 1 mg/ml of mAb-211 (50 ml/well) in 200 mM NaHCO3, pH 9.6, and then.
