The Avidity of Autoreactive Alpha-Synuclein Antibodies in Leucine-Rich Repeat Kinase 2 Mutation Carriers Is Not Altered Compared to Healthy Controls or Patients with Parkinson's Disease.

The accumulation and aggregation of alpha-synuclein (α-Syn) are pathological processes associated with Parkinson's disease, indicating that the regulation of protein is a crucial etiopathological mechanism. Interestingly, human serum and cerebrospinal fluid contain autoantibodies that recognize α-Syn. This potentially demonstrates an already existing, naturally decomposing, and protective system. Thus, quantitative or qualitative alterations, such as the modified antigen binding of so-called naturally occurring autoantibodies against α-Syn (nAbs-α-Syn), may induce disease onset and/or progression. We investigated the serum titers and binding characteristics of nAbs-α-Syn in patients suffering from sporadic Parkinson's disease (n = 38), LRRK2 mutation carriers (n = 25), and healthy controls (n = 22). METHODS: Titers of nAbs-α-Syn were assessed with ELISA and binding affinities and kinetics with SPR. Within the patient cohort, we discriminated between idiopathic and genetic (LRRK2-mutated) variants. RESULTS: ELISA experiments revealed no significant differences in nAbs-α-Syn serum titers among the three cohorts. Moreover, the α-Syn avidity of nAbs-α-Syn was also unchanged. CONCLUSIONS: Our findings indicate that nAbs-α-Syn concentrations or affinities in healthy and diseased persons do not differ, independent of mutations in LRRK2.

Apathy in patients with Alzheimer's disease is a cost-driving factor.

BACKGROUND: Apathy is the most frequent neuropsychiatric symptom in patients with dementia of the Alzheimer's type (DAT). We analyzed the influence of apathy on the resource use of DAT patients and their caregivers. METHODS: Included were baseline data of 107 DAT patients from a randomized clinical trial on apathy treatment. The Resource Utilization in Dementia (RUD) instrument assessed costs over a 1-month period prior to baseline. Cost predictors were determined via a least absolute shrinkage and selection operator (LASSO). RESULTS: On average, total monthly costs were €3070, of which €2711 accounted for caregivers' and €359 for patients' costs. An increase of one point in the Apathy Evaluation Scale resulted in a 4.1% increase in total costs. DISCUSSION: Apathy is a significant cost driving factor for total costs in mild to moderate DAT. Effective treatment of apathy might be associated with reduced overall costs in DAT.

Long-Term Cognitive Decline Related to the Motor Phenotype in Parkinson's Disease.

BACKGROUND: Parkinson's disease (PD) is associated with various non-motor symptoms, including cognitive deterioration. OBJECTIVE: Here, we used data from the DEMPARK/LANDSCAPE cohort to describe the association between progression of cognitive profiles and the PD motor phenotypes: postural instability and gait disorder (PIGD), tremor-dominant (TR-D), and not-determined (ND). METHODS: Demographic, clinical, and neuropsychological six-year longitudinal data of 711 PD-patients were included (age: M = 67.57; 67.4% males). We computed z-transformed composite scores for a priori defined cognitive domains. Analyses were controlled for age, gender, education, and disease duration. To minimize missing data and drop-outs, three-year follow-up data of 442 PD-patients was assessed with regard to the specific role of motor phenotype on cognitive decline using linear mixed modelling (age: M = 66.10; 68.6% males). RESULTS: Our study showed that in the course of the disease motor symptoms increased while MMSE and PANDA remained stable in all subgroups. After three-year follow-up, significant decline of overall cognitive performance for PIGD-patients were present and we found differences for motor phenotypes in attention (ß= -0.08, SE = 0.003, p < 0.006) and memory functions showing that PIGD-patients deteriorate per months by -0.006 compared to the ND-group (SE = 0.003, p = 0.046). Furthermore, PIGD-patients experienced more often difficulties in daily living. CONCLUSION: Over a period of three years, we identified distinct neuropsychological progression patterns with respect to different PD motor phenotypes, with early executive deficits yielding to a more amnestic profile in the later course. Here, in particular PIGD-patients worsened over time compared to TR-D and ND-patients, highlighting the greater risk of dementia for this motor phenotype.

Effects of a Multimerized Recombinant Autoantibody Against Amyloid-ß.

Alzheimer's disease (AD) is the most common neurodegenerative disease; thus, the search for a cure or causal therapy has become necessary. Despite intense research on this topic in recent decades, there is no curative therapy up today, and also no disease-modifying treatment has been approved. As promising approach passive immunization strategies have thereby come forth. In this study, we focused on naturally occurring autoantibodies against the AD-associated peptide amyloid-ß. These antibodies have already reported to show beneficial functions in vitro and in mouse models of AD. However, their availability is limited due to their low abundance in peripheral blood. In a recent study, we were able to generate four recombinant antibodies against amyloid-ß. In the present study, we tested these antibodies in ELISA and SPR assays for their binding behavior and by aggregation- and phagocytosis assays as functional evidences to characterize their amyloid-ß-related neutralizing and clearance abilities. Further ex vivo assay on organotypic hippocampal slice cultures gave first evidence of microglial activation and inflammatory features. The tested recombinant antibodies in IgG format showed, in comparison to naturally occurring autoantibodies against amyloid-ß, insufficient binding capacities and -affinities. However, after conversion of one antibody into a single chain format multimerization of the scFv-Fc construct, the investigated binding capacity and -affinity showed improvements. Further functional assays predict a protective effect of this antibody. Although, all four recombinant antibodies showed binding to amyloid-ß, promising features were only detectable after conversion into a multimeric format. The multimeric scFv-Fc antibody exhibited thereby strong impact on amyloid-ß clearance and inhibition of oligomerization.