Identification of diagnostic and prognostic biomarkers of PD using a multiplex proteomics approach.

Given the complexity of Parkinson's disease (PD), achieving acceptable diagnostic and prognostic accuracy will require the support of a panel of diverse biomarkers. We used Proximity extension assays to measure a panel of 92 proteins in CSF of 120 newly diagnosed PD patients and 45 control subjects without neurological disease. From 75 proteins detectable in the CSF of >90% of the subjects, regularized regression analysis identified four proteins (ß-NGF, CD38, tau and NCAN) as downregulated in newly diagnosed PD patients (age at diagnosis 67.2 ± 9.4 years) compared to controls (age 65.4 ± 10.9 years). Higher tau (ß -0.82 transformed MMSE points/year, 95% CI -1.37 to -0.27, P = 0.005) was also linked to faster cognitive decline over the first ten years after PD diagnosis. These findings provide insights into multiple aspects of PD pathophysiology and may serve as the foundation for identifying new biomarkers and therapeutic targets.

Practices and Attitudes of Bavarian Stakeholders Regarding the Secondary Use of Health Data for Research Purposes During the COVID-19 Pandemic: Qualitative Interview Study.

BACKGROUND: The COVID-19 pandemic is a threat to global health and requires collaborative health research efforts across organizations and countries to address it. Although routinely collected digital health data are a valuable source of information for researchers, benefiting from these data requires accessing and sharing the data. Health care organizations focusing on individual risk minimization threaten to undermine COVID-19 research efforts, and it has been argued that there is an ethical obligation to use the European Union's General Data Protection Regulation (GDPR) scientific research exemption during the COVID-19 pandemic to support collaborative health research. OBJECTIVE: This study aims to explore the practices and attitudes of stakeholders in the German federal state of Bavaria regarding the secondary use of health data for research purposes during the COVID-19 pandemic, with a specific focus on the GDPR scientific research exemption. METHODS: Individual semistructured qualitative interviews were conducted between December 2020 and January 2021 with a purposive sample of 17 stakeholders from 3 different groups in Bavaria: researchers involved in COVID-19 research (n=5, 29%), data protection officers (n=6, 35%), and research ethics committee representatives (n=6, 35%). The transcripts were analyzed using conventional content analysis. RESULTS: Participants identified systemic challenges in conducting collaborative secondary-use health data research in Bavaria; secondary health data research generally only happens when patient consent has been obtained, or the data have been fully anonymized. The GDPR research exemption has not played a significant role during the pandemic and is currently seldom and restrictively used. Participants identified 3 key groups of barriers that led to difficulties: the wider ecosystem at many Bavarian health care organizations, legal uncertainty that leads to risk-adverse approaches, and ethical positions that patient consent ought to be obtained whenever possible to respect patient autonomy. To improve health data research in Bavaria and across Germany, participants wanted greater legal certainty regarding the use of pseudonymized data for research purposes without the patient's consent. CONCLUSIONS: The current balance between enabling the positive goals of health data research and avoiding associated data protection risks is heavily skewed toward avoiding risks; so much so that it makes reaching the goals of health data research extremely difficult. This is important, as it is widely recognized that there is an ethical imperative to use health data to improve care. The current approach also creates a problematic conflict with the ambitions of Germany, and the federal state of Bavaria, to be a leader in artificial intelligence. A recent development in the field of German public administration known as norm screening (Normenscreening) could potentially provide a systematic approach to minimize legal barriers. This approach would likely be beneficial to other countries.

Next-Generation RNA-Sequencing of Serum Small Extracellular Vesicles Discovers Potential Diagnostic Biomarkers for Dementia With Lewy Bodies.

OBJECTIVE: There is an urgent clinical need for identifying blood-based diagnostic biomarkers for Dementia with Lewy Bodies (DLB). Transcriptomic studies have reported unique RNA changes in postmortem DLB brains. Small extracellular vesicles (SEV) that transport RNA between brain and peripheral circulation enable identifying molecular changes in living human brain. Hence, we aimed to identify differentially expressed RNA in serum SEVs from people with DLB. METHODS: We investigated serum SEV total RNA profiles in people with DLB (n = 10) and age and gender matched comparisons (n = 10) using next-generation RNA-sequencing. SEVs were separated by ultracentrifugation with density gradient and were characterized by nanoparticle analysis and western blotting. We verified the differential expression levels of identified differentially expressed genes (DEG) using high-throughput qPCR. Functional implications of identified DEG were evaluated using Ingenuity pathway analyses. RESULTS: We identified 846 nominally significant DEG including 30 miRNAs in DLB serum SEVs. We identified significant downregulation of proinflammatory genes, IL1B, CXCL8, and IKBKB. Previously reported postmortem DLB brain DEGs were significantly enriched (χ2=4.99; df=1; p = 0.03) among the identified DEGs, and the differential expression of 40 postmortem DLB brain DEGs could be detected in serum SEVs of people living with DLB. Functional pathway and network analyses highlighted the importance of immunosenescence, ubiquitin proteasome system (UPS) dysfunction, DNA repair, and RNA post-transcriptional modification deficits in DLB pathology. CONCLUSION: Identified DEGs, especially reduced expression levels of inflammation, and UPS-associated RNA, may aid diagnosing DLB, and their biomarker potential warrants further investigation in larger clinical cohorts. Our findings corroborate the absence of chronic neuroinflammation in DLB.

Podcasts as a teaching tool in orthopaedic surgery : Is it beneficial or more an exemption card from attending lectures?

OBJECTIVE: The aim of this study was to evaluate the influence of the introduction of online podcasts as part of the main lecture series in orthopaedics on the number of lecture attendees, the examination results and the assessment of teaching by the students. Additionally, we evaluated the use of other media for examination preparation. METHODOLOGY: At the beginning and end of the lecture series questionnaires were handed out to the students to evaluate their attitudes towards attending lectures, the use of video podcasts and examination preparation. In addition, the number of lecture attendees and podcast usage during the semester were counted and the statements of the students in the evaluation assessments of orthopaedic teaching were evaluated. The examination results were correlated in a statistical analysis with the learning materials provided by the students for examination preparation. RESULTS: At the end of the lecture series, 284 students stated that they used the lecture podcast about twice as often as attending lectures; however, for the majority of the students the provision of a video podcast was no reason not to attend the lecture. For example, 37.2% stated that they never and 26.8% stated that they rarely had not attended the lecture by providing the podcasts. Of the students 91-95% considered the availability of lecture podcasts to be a rather meaningful or very meaningful supplement to the lecture visit. Students increasingly used digital media to prepare for examinations instead of using traditional analogue methods. None of the learning methods or materials examined showed a statistically significant advantage in examination results. CONCLUSION: Students in the age of digitalization use a variety of learning materials and are no longer bound to classical analog teaching methods. The use of online podcasts had no negative impact on examination performance. Most students perceived lecture podcasts as a useful supplement to lecture attendance. The students praised the expansion of the teaching curriculum to include additional digital offers with positive comments in the evaluations, but without achieving an improvement in these student evaluations.

Validation of a new assay for α-synuclein detection in cerebrospinal fluid.

BACKGROUND: Abnormal α-synuclein aggregation and deposition is the pathological hallmark of Parkinson's disease (PD) and dementia with Lewy bodies (DLB), but is also found in Alzheimer disease (AD). Therefore, there is a gaining interest in α-synuclein in cerebrospinal fluid (CSF) as potential biomarker for these neurodegenerative diseases. To broaden the available choices of α-synuclein measurement in CSF, we developed and validated a new assay for detecting total α-synuclein. METHODS: This novel ELISA uses commercially available antibodies and is based on electrochemiluminescence technology. The assay protocol is straightforward, with short and simple incubation steps, and requires only small amounts of CSF. We validated this assay for precision, parallelism, dilution linearity, specificity, and spike recovery. We further compared it to the newly validated α-synuclein assay from BioLegend by analyzing a set of 50 CSF samples with both assays. RESULTS: The new assay quantifies α-synuclein in CSF with a lower limit of detection of 36.3 pg/mL and shows no cross-reactivity with human ß- and γ-synuclein. Results of dilution linearity, parallelism, spike recovery, and precision classify this assay as well suited for α-synuclein detection in human CSF samples. CONCLUSIONS: We present a novel assay based on freely available components to quantify total α-synuclein in CSF as an additional method for α-synuclein as a biomarker in neurodegenerative diseases. The assay convinces with its simple and convenient protocol paired with high sensitivity.

Patient reported outcome measurements in the diagnosis of incisional hernia: PROMIS questionnaire, a pilot study.

BACKGROUND: Incisional hernia (IH) is the most frequent complication after abdominal surgery. Long-term follow-up is crucial. Patient-reported outcome measurements (PROMs) are able to monitor patients' disease progression after treatment. Until now, there are no PROMs that assess patients after abdominal surgery or that detects patients with IH. We aimed to develop a reliable questionnaire to assist in diagnosing IH, called the "PROMIS questionnaire": Patient-Reported Outcome Measurements in the Diagnosis of Incisional Hernias. In this pilot study, the reliability of this questionnaire is being determined. METHODS: Patients diagnosed with IH between 2013 and 2014 were included. A questionnaire with seven questions was developed. Patients were asked whether they thought they had IH, whether they felt any pain at the site of the scar, and whether they saw or felt a lump or a bulge. Furthermore, smoking history and patients' weight and height were taken into account. Patients were approached three times by telephone, with an interval of 1 week. Test-retest reliability, internal consistency, and sensitivity were measured. RESULTS: Forty-three patients were included. Test-retest reliability was 1.0, and internal consistency was 0.56. The question regarding patients' pain was least consistent with other questions. The overall sensitivity of the questionnaire was 95%. CONCLUSIONS: The PROMIS questionnaire is a highly reliable questionnaire, but the internal consistency is modest. The clinical relevancy of pain in IH patients is essential. Therefore, this question will be kept in the current PROMIS questionnaire. It needs further validation in a prospective cohort study, to use it as a diagnostic tool in the future to detect IH.

Müller glial cells inhibit proliferation of retinal endothelial cells via TGF-ß2 and Smad signaling.

Neovascularization is a sight-threatening complication of ischemic proliferative retinopathies. Transforming growth factor (TGF)-ß, a cytokine with multiple functions in the retina, participates in the control of pathological angiogenesis and neovascularization. Retinal glial (Müller) cells produce TGF-ß2 under physiological and post-ischemic conditions. To characterize glial cell-derived mediators of angiogenesis regulation in glial-endothelial interactions in the retina, we co-cultured primary Müller cells and bovine microvascular retinal endothelial cells (BRECs). Müller cell-derived TGF-ß2 was bound by the BRECs, which were found to express serine/threonine kinase TGF-ß receptors, and stimulated TGF-ß-dependent anti-proliferative signaling pathways. The proliferation of BRECs was attenuated by exogenous TGF-ß2 as well as by the presence of Müller cell culture media. The following intracellular signaling mechanisms were found to be involved in the anti-angiogenic action of Müller cell-derived TGF-ß2: (i) binding of TGF-ß2 to BRECs is mediated by the type-II TGF-ß receptor, leading to (ii) activation and phosphorylation of receptor-activated Smads; (iii) Müller cell-derived TGF-ß2 activates Smad2 and Smad3 to (iv) attenuate the phosphorylation state of the MAP kinases, extracellular signal-regulated kinase (ERK)-1/-2. Neutralizing TGF-ß or TGF-ß type-II receptor or blocking the activation of Smads partially abrogated the effect of Müller cell-conditioned media on BRECs. Together, our data suggest that Müller cells release TGF-ß2, inhibiting the proliferation of retinal endothelial cells via activation of Smad2/Smad3 and attenuation of ERK signaling. Given the context-dependent action of TGF-ß2 on angiogenesis, our results may have implications for understanding the pathogenesis of retinal angiopathies, such as diabetic retinopathy, and the anti-angiogenic role of TGF-ß therein.

Cerebrospinal fluid amyloid-ß and phenotypic heterogeneity in de novo Parkinson's disease.

BACKGROUND: In Parkinson's disease (PD), the motor presentation characterised by postural instability/gait difficulties (PIGD) heralds accelerated motor, functional and cognitive decline, as compared with the more benign tremor-dominant (TD) variant. This makes the PIGD complex an attractive target for the discovery of prognostic biomarkers in PD. OBJECTIVE: To explore in vivo whether variability in brain amyloid-ß (Aß) metabolism affects the initial motor presentation in PD. METHODS: We quantified cerebrospinal fluid (CSF) concentrations and ratios of Aß42, Aß40 and Aß38 using a triplex immunoassay in 99 patients with de novo PD with the PIGD phenotype (n=39) or the TD phenotype (n=60). All patients underwent standardised assessments of motor and neuropsychological function and cerebral MRI. 46 age-matched normal controls served as external reference. RESULTS: Patients with PD with the PIGD phenotype had significantly reduced CSF Aß42, Aß38, Aß42/40 and Aß38/40 levels compared with patients with the TD phenotype and controls. CSF marker levels in patients with PD-TD did not differ from those in controls. Multivariate regression models demonstrated significant associations of CSF Aß markers with severity of PIGD and lower limb bradykinesia in patients with PD, independently from age, MRI white matter hyperintensities and cognition. No associations were found between CSF markers and other motor features. CONCLUSIONS: Motor heterogeneity in de novo PD independently relates to CSF Aß markers, with low levels found in patients with the PIGD presentation. This suggests that disturbed Aß metabolism has an effect on PD beyond cognition and may contribute to the variable rate of motor and functional decline in PD.

Seed Amplification Assay as a Diagnostic Tool in Newly-Diagnosed Parkinson's Disease.

Seed amplification assays (SAA) are the first credible molecular assay for Parkinson's disease (PD). However, the value of SAA to support the clinicians' initial diagnosis of PD is not clear. In our study, we analyzed cerebrospinal fluid samples from 121 PD patients recruited through population screening methods and taken within a median delay of 38 days from diagnosis and 51 normal controls without neurodegenerative disease. SAA yielded a sensitivity of 82.6% (95% CI, 74.7% - 88.9%) and specificity of 88.2% (95% CI, 76.1% - 95.6%). These results highlight the potential of SAA to support the initial diagnosis of PD in clinical practice and research.

Cognitive Profile in Parkinson's Disease Dementia Patients with Low versus Normal Cerebrospinal Fluid Amyloid Beta.

Introduction: In patients with Parkinson's disease (PD), low cerebrospinal fluid (CSF) amyloid beta 1-42 (Ab42) at baseline is the most consistent CSF biomarker as a risk factor for developing dementia. Low CSF Ab42 is, however, a typical hallmark of Alzheimer's disease (AD). Hence, low CSF Ab42 in patients with PD may indicate presence of comorbid AD pathology and may predict a more AD-like cognitive profile when they develop dementia. Our study aimed to investigate if low CSF Ab42 at baseline is associated with a more AD-like cognitive profile in PD patients with dementia. Methods: In a prospectively followed-up, population-based cohort of newly diagnosed PD patients, we compared the cognitive profile of dementia in those with a low CSF Ab42 level at baseline with that of patients who had normal levels at the time when they developed dementia. Four different cognitive domain z-scores (memory, attention, executive, visuospatial) were calculated. Patients were subdivided into three tertiles or categorized dichotomously based on the baseline CSF Ab42 levels as measured by electrochemiluminescence and ELISA. Results: During 10-year follow-up, 37 patients met the inclusion criteria. Memory domain composite z-scores, memory subtest z-scores, and the difference between long-delay free recall versus recognition scores were not significantly different between the groups. Composite z-scores of visuospatial functions significantly differed between the tertiles, which was not significant after Bonferroni correction. In the dichotomous group analysis, z-scores of visuospatial functions significantly differed between the two groups. The other cognitive domain z-scores were not significantly different. Conclusions: In patients with PD dementia, low CSF Ab42 level at baseline is not associated with a specific cognitive profile.

Association of CSF Glucocerebrosidase Activity With the Risk of Incident Dementia in Patients With Parkinson Disease.

BACKGROUND AND OBJECTIVES: Variations in the glucocerebrosidase gene (GBA) are common risk factors for Parkinson disease (PD) and dementia in PD (PDD) and cause a reduction in the activity of the lysosomal enzyme glucocerebrosidase (GCase). It is anticipated that GCase dysfunction might contribute to a more malignant disease course and predict cognitive impairment in PD, although evidence is lacking. We aimed to discover whether CSF GCase activity is altered in newly diagnosed patients with PD and associated with future development of dementia. METHODS: Patients with PD were participants of the ongoing population-based longitudinal ParkWest study in Southwestern Norway and were followed prospectively for up to 10 years. CSF was collected at diagnosis, and GBA carrier status was obtained. Control samples were from persons without neurodegenerative disorders. GCase activity was measured using a validated assay. PD dementia diagnosis was set according to the Movement Disorder Society criteria, and parametric accelerated failure time models were applied to analyze the association of GCase activity with dementia-free survival. RESULTS: This study enrolled 117 patients with PD (mean age 67.2 years, including 12 GBA non-synonymous variant carriers) and 50 control participants (mean age 64 years). At the time of diagnosis, GCase activity was reduced in patients with PD with (mean ± SD, 0.92 ± 0.40 mU/mg, n = 12) or without GBA variations (1.00 ± 0.37 mU/mg, n = 105) compared with controls (1.20 ± 0.35, n = 50). GCase activity at the time of diagnosis was lower in patients with PD who developed dementia within 10 years (0.85 ± 0.27 mU/mg, n = 41) than in those who did not (1.07 ± 0.40 mU/mg, n = 76, p = 0.001). A 0.1-unit reduction in baseline GCase activity was associated with a faster development of PDD (hazard ratio 1.15, 95% CI 1.03-1.28, p = 0.014). DISCUSSION: The association of early CSF GCase activity with long-term progression to PD dementia will have important implications for the design of clinical trials for GCase targeting therapies and patient management. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that reduced CSF GCase activity at the time of PD diagnosis is associated with an increased risk for later development of PDD.

Inflammatory Biomarkers in Newly Diagnosed Patients With Parkinson Disease and Related Neurodegenerative Disorders.

BACKGROUND AND OBJECTIVES: Neuroinflammation contributes to Parkinson disease (PD) pathology, and inflammatory biomarkers may aid in PD diagnosis. Proximity extension assay (PEA) technology is a promising method for multiplex analysis of inflammatory markers. Neuroinflammation also plays a role in related neurodegenerative diseases, such as dementia with Lewy bodies (DLB) and Alzheimer disease (AD). The aim of this work was to assess the value of inflammatory biomarkers in newly diagnosed patients with PD and in patients with DLB and AD. METHODS: Patients from the Norwegian ParkWest and Dementia Study of Western Norway longitudinal cohorts (PD, n = 120; DLB, n = 15; AD, n = 27) and 44 normal controls were included in this study. A PEA inflammation panel of 92 biomarkers was measured in the CSF. Disease-associated biomarkers were identified using elastic net (EN) analysis. We assessed the discriminatory power of disease-associated biomarkers using receiver operating characteristic (ROC) curve analysis and estimated the optimism-adjusted area under the curve (AUC) using the bootstrapping method. RESULTS: EN analysis identified 9 PEA inflammatory biomarkers (ADA, CCL23, CD5, CD8A, CDCP1, FGF-19, IL-18R1, IL-6, and MCP-2) associated with PD. Seven of the 9 biomarkers were included in a diagnostic panel, which was able to discriminate between those with PD and controls (optimism-adjusted AUC 0.82). Our 7-biomarker PD panel was also able to distinguish PD from DLB and from AD. In addition, 4 inflammatory biomarkers were associated with AD and included in a panel, which could distinguish those with AD from controls (optimism-adjusted AUC 0.87). Our 4-biomarker AD panel was also able to distinguish AD from DLB and from PD. DISCUSSION: In our exploratory study, we identified a 7-biomarker panel for PD and a 4-biomarker panel for AD. Our findings indicate potential inflammation-related biomarker candidates that could contribute toward PD-specific and AD-specific diagnostic panels, which should be further explored in other larger cohorts.

The axon guidance molecule Netrin-4 is expressed by Müller cells and contributes to angiogenesis in the retina.

Retinal glial (Müller) cells are involved in a wide range of developmental mechanisms, including axon guidance and angiogenesis. This study was undertaken to explore whether Netrin-4, an axonal guidance molecule, is expressed by Müller cells and promotes angiogenesis-related activities. Netrin-4 was found through all retinal layers, and its expression was demonstrated in Müller cells, retinal pigment epithelium cells and bovine retinal endothelial cells (BRECs). Co-localization of Netrin-4 with Müller cell-specific molecules [cellular retinaldehyde-binding protein (cRALBP), vimentin] was observed in the ganglion cell layer, nerve fiber layer, and at the outer limiting membrane. Under hypoxic conditions, the release of Netrin-4 from Müller cells was increased, with mRNA levels upregulated in a hypoxia-inducible factor-1-dependent manner and dependent on the concomitantly induced release of vascular endothelial growth factor. These findings were consistent with an intensified immunofluorescence of Netrin-4 labeling in the postischemic retinas after ischemia-reperfusion. Netrin-4 stimulated BRECs to increase phosphorylation of the mitogen-activated protein (MAP) kinases, extracellular signal-regulated kinase (ERK)-1/-2, and p38, in a dose-dependent manner. Synthetic inhibitors of the MAP kinases were able to suppress Netrin-4-induced migration and proliferation of BRECs suggesting that both MAP kinases are differentially involved in Netrin-4-induced angiogenesis. Two receptors for Netrins, i.e., deleted in colorectal cancer (DCC) and uncoordinated-5-homolog 1 (Unc5H1), were detected in BRECs. DCC is at least partially required for Netrin-4-induced activation of ERK-1/-2. These data suggest that Müller glial cells contribute to, and may modulate, retinal Netrin-4 levels. This may be a novel pathway of Müller cell-mediated control of retinal angiogenesis, particularly under hypoxic/ischemic conditions when the cells upregulate Netrin-4 expression.

A systematic review of associations between common SNCA variants and clinical heterogeneity in Parkinson's disease.

There is great heterogeneity in both the clinical presentation and rate of disease progression among patients with Parkinson's disease (PD). This can pose prognostic difficulties in a clinical setting, and a greater understanding of the risk factors that contribute to modify disease course is of clear importance for optimizing patient care and clinical trial design. Genetic variants in SNCA are an established risk factor for PD and are candidates to modify disease presentation and progression. This systematic review aimed to summarize all available primary research reporting the association of SNCA polymorphisms with features of PD. We systematically searched PubMed and Web of Science, from inception to 1 June 2020, for studies evaluating the association of common SNCA variants with age at onset (AAO) or any clinical feature attributed to PD in patients with idiopathic PD. Fifty-eight studies were included in the review that investigated the association between SNCA polymorphisms and a broad range of outcomes, including motor and cognitive impairment, sleep disorders, mental health, hyposmia, or AAO. The most reproducible findings were with the REP1 polymorphism or rs356219 and an earlier AAO, but no clear associations were identified with an SNCA polymorphism and any individual clinical outcome. The results of this comprehensive summary suggest that, while there is evidence that genetic variance in the SNCA region may have a small impact on clinical outcomes in PD, the mechanisms underlying the association of SNCA polymorphisms with PD risk may not be a major factor driving clinical heterogeneity in PD.

Validation and assessment of preanalytical factors of a fluorometric in vitro assay for glucocerebrosidase activity in human cerebrospinal fluid.

Lysosomal dysfunction is an emerging feature in the pathology of Parkinson's disease and Dementia with Lewy bodies. Mutations in the GBA gene, encoding the enzyme Glucocerebrosidase (GCase), have been identified as a genetic risk factor for these synucleinopathies. As a result, there has been a growing interest in the involvement of GCase in these diseases. This GCase activity assay is based on the catalytic hydrolysis of 4-methylumbelliferyl ß-D-glucopyranoside that releases the highly fluorescent 4-methylumbelliferyl (4-MU). The final assay protocol was tested for the following parameters: Lower limit of quantification (LLOQ), precision, parallelism, linearity, spike recovery, number of freeze-thaw events, and sample handling stability. The GCase activity assay is within acceptable criteria for parallelism, precision and spike recovery. The LLOQ of this assay corresponds to an enzymatic activity of generating 0.26 pmol 4-MU/min/ml. The enzymatic activity was stable when samples were processed and frozen at - 80 °C within 4 h after the lumbar puncture procedure. Repetitive freeze-thaw events significantly decreased enzyme activity. We present the validation of an optimized in vitro GCase activity assay, based on commercially available components, to quantify its enzymatic activity in human cerebrospinal fluid and the assessment of preanalytical factors.

Association of SNCA Parkinson's Disease Risk Polymorphisms With Disease Progression in Newly Diagnosed Patients.

Objectives: To evaluate the impact of SNCA polymorphisms originally identified as risk factors for Parkinson's disease (PD) on the clinical presentation and progression of the disease in a large cohort of population-based patients with incident PD. Methods: Four hundred thirty-three patients and 417 controls from three longitudinal cohorts were included in the study. Disease progression was recorded annually for up to 9 years using the Unified Parkinson's Disease Rating Scale (UPDRS) or Mini-Mental State Examination. Genotypes for five variants within the SNCA locus (rs2870004, rs356182, rs5019538, rs356219, and rs763443) were determined. We studied the association between each variant and disease progression using linear mixed-effects regression models. Results: The clinical profile of the patients with PD at the point of diagnosis was highly uniform between genotype groups. The rs356219-GG genotype was associated with a higher UPDRS II score than A-allele carriers (ß = 1.52; 95% confidence interval 0.10-2.95; p = 0.036), but no differences were observed in the rate of progression of the UPDRS II scores. rs356219-GG was also associated with a faster annual change in Mini-Mental State Examination score compared with A-carriers (ß = 0.03; 95% confidence interval 0.00-0.06; p = 0.043). Conclusions: We show that the known PD-risk variant rs356219 has a minor effect on modifying disease progression, whereas no differences were associated with rs2870004, rs356182, rs5019538, and rs763443. These findings suggest that SNCA variants associated with PD risk may not be major driving factors to the clinical heterogeneity observed for PD.

The role of ADGRE5/CD97 in human retinal pigment epithelial cell growth and survival.

Cell surface molecules of retinal pigment epithelial (RPE) cells participate in the pathogenesis of retinal diseases. In an attempt to identify cell surface proteins that play a role in RPE cell-cell interactions, we have considered studying the expression, regulation, and signaling of ADGRE5/CD97, an adhesion G protein-coupled receptor family member, based on its known adhesive function in other cell types such as leukocytes. We showed that RPE cells express three isoforms of CD97 and identified inflammation-related cytokines as important mediators regulating CD97 expression. Whereas TNF-α and IFN-γ upregulated CD97, TGF-ß decreased CD97 expression. Due to interaction with CD55, ARPE-19 cells firmly adhered to monocytes and T lymphocytes when overexpressing CD97, suggesting a role for CD97 in controlling leukocyte infiltration across the RPE-based blood-retinal barrier. CD97-mediated signaling acted synergistically with PDGF-BB and IFN-γ to regulate cell growth and survival, ensuring a cellular balance under inflammatory conditions. These findings suggest that CD97 on RPE cells serves to control leukocyte activation and trafficking in uveoretinal inflammation while at the same time regulating second messenger-mediated gene expression, cell growth, and survival.

Kynurenines, Neuropsychiatric Symptoms, and Cognitive Prognosis in Patients with Mild Dementia.

INTRODUCTION: Circulating tryptophan (Trp) and its downstream metabolites, the kynurenines, are potentially neuroactive. Consequently, they could be associated with neuropsychiatric symptoms and cognitive prognosis in patients with dementia. OBJECTIVE: The objective of this study was to assess associations between circulating kynurenines, cognitive prognosis, and neuropsychiatric symptoms. METHODS: We measured baseline serum Trp, neopterin, pyridoxal 5'-phosphate (PLP), and 9 kynurenines in 155 patients with mild dementia (90 with Alzheimer's disease, 65 with Lewy body dementia). The ratios between kynurenine and Trp and kynurenic acid (KA) to kynurenine (KKR) were calculated. The Mini-Mental State Examination (MMSE) and the Neuropsychiatric Inventory (NPI) were administered at baseline and annually over 5 years. Associations between baseline metabolite concentrations with MMSE and the NPI total score were assessed using a generalized structural equation model (mixed-effects multiprocess model), adjusted for age, sex, current smoking, glomerular filtration rate, and PLP. Post hoc associations between KKRs and individual NPI items were assessed using logistic mixed-effects models. False discovery rate (0.05)-adjusted P values (Q values) are reported. RESULTS: Kynurenine had a nonlinear quadratic relationship with the intercept of the MMSE scores over 5 years (Q < 0.05), but not with the slope of MMSE decline. Kynurenine was associated with a higher NPI total score over time (Q < 0.001). Post hoc, both KKR and KA were associated with more hallucinations (Q < 0.05). CONCLUSIONS: Kynurenine has a complex relationship with cognition, where both low and high levels were associated with poor cognitive performance. A higher KKR indicated risk for neuropsychiatric symptoms, especially hallucinations.