Education as risk factor of Mild Cognitive Impairment - the role of the gut microbiome. Presentation in symposium: Social determinants of brain health: From the search for mechanisms to recommendations to increase equity

Scientific Conference (2023, November)

Polygenic risk scores validated in patient-derived cells stratify for mitochondrial subtypes of Parkinson\textquoterights disease 2023.05.12.23289877

E-print/Working paper (2023)

Background Parkinson's disease (PD) is the fastest growing neurodegenerative disorder, with affected individuals expected to double during the next 20 years. This raises the urgent need to better ... [more ▼]

Background Parkinson's disease (PD) is the fastest growing neurodegenerative disorder, with affected individuals expected to double during the next 20 years. This raises the urgent need to better understand the genetic architecture and downstream cellular alterations underlying PD pathogenesis, in order to identify more focused therapeutic targets. While only ~10\% of PD cases can be clearly attributed to monogenic causes, there is mounting evidence that additional genetic factors could play a role in idiopathic PD (iPD). In particular, common variants with low to moderate effect size in multiple genes regulating key neuroprotective activities may act as risk factors for PD. In light of the well-established involvement of mitochondrial dysfunction in PD, we hypothesized that a fraction of iPD cases may harbour a pathogenic combination of common variants in nuclear-encoded mitochondrial genes, ultimately resulting in neurodegeneration.Methods: To capture this mitochondria-related 'missing heritability', we leveraged on existing data from previous genome-wide association studies (GWAS) i.e., the large PD GWAS from Nalls and colleagues. We then used computational approaches based on mitochondria-specific polygenic risk scores (mitoPRSs) for imputing the genotype data obtained from different iPD case-control datasets worldwide, including the Luxembourg Parkinson\textquoterights Study (412 iPD patients and 576 healthy controls) and the COURAGE-PD cohorts (7270 iPD cases and 6819 healthy controls).Results: Applying this approach to gene sets controlling mitochondrial pathways potentially relevant for neurodegeneration in PD, we demonstrated that common variants in genes regulating Oxidative Phosphorylation (OXPHOS-PRS) were significantly associated with a higher PD risk both in the Luxembourg Parkinson\textquoterights Study (odds ratio, OR=1.31[1.14-1.50], p=5.4e-04) and in COURAGE-PD (OR=1.23[1.18-1.27], p=1.5e-29). Functional analyses in primary skin fibroblasts and in the corresponding induced pluripotent stem cells-derived neuronal progenitor cells from Luxembourg Parkinson's Study iPD patients stratified according to the OXPHOS-PRS, revealed significant differences in mitochondrial respiration between high and low risk groups (p < 0.05). Finally, we also demonstrated that iPD patients with high OXPHOS-PRS have a significantly earlier age at disease onset compared to low-risk patients.Conclusions: Our findings suggest that OXPHOS-PRS may represent a promising strategy to stratify iPD patients into pathogenic subgroups in which the underlying neurodegeneration is due to a genetically defined mitochondrial burden potentially eligible for future, more tailored mitochondrially targeted treatments. [less ▲]

Early-to-mid idiopathic Parkinson’s disease shows a more cytotoxic but declined CD8-regulatory peripheral immune profile

E-print/Working paper (2022)

Parkinson’s disease (PD) is the second most common neurodegenerative disease. Brain neuroinflammation plays a role in PD pathogenesis. However, the involvement of the peripheral immune system has not been ... [more ▼]

Parkinson’s disease (PD) is the second most common neurodegenerative disease. Brain neuroinflammation plays a role in PD pathogenesis. However, the involvement of the peripheral immune system has not been systematically investigated. Here we analyzed >700 combinatorial immunological features in fresh blood of 28 early-to-mid-stage PD patients and 24 matched controls. We found an enhanced cytotoxic immune profile in idiopathic PD patients (iPD), with a higher frequency of terminally-differentiated effector CD8 T (TEMRA), late-differentiated CD8+ natural killer T cells and neutrophils. This immune profile was intensified by elevated serum granzyme A, reduced percentages of CD8+FOXP3+ regulatory T cells and group 2 innate lymphoid cells with immunosuppressive or tolerance-inducing functions. The frequency of CD8 TEMRA was negatively correlated with disease duration, suggesting a contribution to PD pathogenesis. Our work provides a comprehensive map on disturbed peripheral adaptive and innate immune cells in early-to-mid iPD, proposing easily-accessible candidates for early diagnosis and treatments. [less ▲]

Polygenic Resilience Modulates the Penetrance of Parkinson Disease Genetic Risk Factors

in Annals of Neurology (2022)

Objective: The aim of the current study is to understand why some individuals avoid developing Parkinson disease (PD) despite being at relatively high genetic risk, using the largest datasets of ... [more ▼]

Objective: The aim of the current study is to understand why some individuals avoid developing Parkinson disease (PD) despite being at relatively high genetic risk, using the largest datasets of individual-level genetic data available. Methods: We calculated polygenic risk score to identify controls and matched PD cases with the highest burden of genetic risk for PD in the discovery cohort (International Parkinson's Disease Genomics Consortium, 7,204 PD cases and 9,412 controls) and validation cohorts (Comprehensive Unbiased Risk Factor Assessment for Genetics and Environment in Parkinson's Disease, 8,968 cases and 7,598 controls; UK Biobank, 2,639 PD cases and 14,301 controls; Accelerating Medicines Partnership–Parkinson's Disease Initiative, 2,248 cases and 2,817 controls). A genome-wide association study meta-analysis was performed on these individuals to understand genetic variation associated with resistance to disease. We further constructed a polygenic resilience score, and performed multimarker analysis of genomic annotation (MAGMA) gene-based analyses and functional enrichment analyses. Results: A higher polygenic resilience score was associated with a lower risk for PD (β = −0.054, standard error [SE] = 0.022, p = 0.013). Although no single locus reached genome-wide significance, MAGMA gene-based analyses nominated TBCA as a putative gene. Furthermore, we estimated the narrow-sense heritability associated with resilience to PD (h2 = 0.081, SE = 0.035, p = 0.0003). Subsequent functional enrichment analysis highlighted histone methylation as a potential pathway harboring resilience alleles that could mitigate the effects of PD risk loci. Interpretation: The present study represents a novel and comprehensive assessment of heritable genetic variation contributing to PD resistance. We show that a genetic resilience score can modify the penetrance of PD genetic risk factors and therefore protect individuals carrying a high-risk genetic burden from developing PD. ANN NEUROL 2022 [less ▲]

The retrograde procedural memory in people with Parkinson’s disease with or without freezing of gait – a cross-sectional study

Poster (2021, September 17)

Objective: To investigate the retrograde procedural memory in people with typical Parkinson’s disease (PwP) with or without freezing of gait (FOG). We hypothesized that the retrograde procedural memory is ... [more ▼]

Objective: To investigate the retrograde procedural memory in people with typical Parkinson’s disease (PwP) with or without freezing of gait (FOG). We hypothesized that the retrograde procedural memory is more strongly impaired in patients with FOG (FOG+) than in patients without FOG (FOG-). Background: Given that cognitive functions, like executive control and automaticity, are crucial for mobility, it is of great importance to get a deeper knowledge of the cognitive impairment that may interfere with walking and causing gait disturbances in PwP, i.e. FOG. The integrity of retrograde procedural memory, the ability to execute skills that have been learned in earlier life stages, is essential for a person’s ability to complete routine, procedural activities like walking. As FOG is characterized as a de-automatization disorder, we hypothesized an impairment of the retrograde procedural memory in patients with FOG. Methods: A total of 194 patients from the Luxembourg Parkinson’s study were included into the cross-sectional study. All patients were assigned to the FOG+ / FOG- groups based on a semi-structured interview conducted by a study physician. The extended evaluation system of the cube copying test was applied to evaluate both the cube-drawing procedure, representing the retrograde procedural memory, and the final result, representing the visuo-constructive abilities (Pauly et al., 2020, MDS abstract). We compared the cube copying performance of n=97 FOG+ with n=97 age-, gender- and education-matched FOG-. Results: FOG+ scored lower on the cube copying procedure compared to the FOG- (p=0.027), which is suggestive of an impaired retrograde procedural memory in FOG+. No significant differences in the visuo-constructional abilities were detected (p=0.945). Conclusion: In line with FOG being considered a de-automatization of walking, a skill acquired in earlier life stages, the present results suggest that PwP with FOG have an impaired retrograde procedural memory in comparison to PwP without FOG. The results lend support to the ability of the extended evaluation system of the cube copying test to assess impaired retrograde procedural memory and help improve our understanding of behavioral symptoms in PwP. [less ▲]

Prevalence of SARS-CoV-2 infection in the Luxembourgish population: the CON-VINCE study.

E-print/Working paper (2020)

BACKGROUND: After the World Health Organization declared the outbreak of coronavirus disease to be a public health emergency of international concern on January 30, 2020, the first SARS-CoV-2 infection ... [more ▼]

BACKGROUND: After the World Health Organization declared the outbreak of coronavirus disease to be a public health emergency of international concern on January 30, 2020, the first SARS-CoV-2 infection was detected in Luxembourg on February 29, 2020. Representative population-based data, including asymptomatic individuals for assessing the viral spread and immune response were, however, lacking worldwide. METHODS: Using a panel-based method, we implemented a representative sample of the Luxembourgish population based on age, gender and residency for testing for SARS-CoV-2 infection and antibody status in order to define prevalence irrespective of clinical symptoms. Participants were contacted via email to fill an online questionnaire before biosampling at local laboratories. All participants provided information related to clinical symptoms, epidemiology, socioeconomic and psychological assessments and underwent biosampling, rRT-PCR testing and serology for SARS-CoV-2. RESULTS: We included a total of 1862 individuals in our representative sample of the general Luxembourgish population. Of these, 5 individuals had a current positive result for infection with SARS-CoV-2 based on rRT-PCR. Four of these individuals were oligosymptomatic and one was asymptomatic. Overall we found a positive IgG antibody status in 35 individuals (1.97%), of which 11 reported to be tested positive by rRT-PCR for SARS-CoV-2 previously and showed in addition their IgG positive status also a positive status for IgA. Our data indicate a prevalence of 0.3% for active SARS-CoV-2 infection and an infection rate of 2.15% in the Luxembourgish population between 18 and 79 years of age. CONCLUSIONS: Luxembourgish residents show a low rate of acute infections after 7 weeks of confinement and present with an antibody profile indicative of a more recent immune response to SARS-CoV-2. All infected individuals were oligo- or asymptomatic. Bi-weekly follow-up visits over the next 2 months will inform about the viral spread by a- and oligosymptomatic carriers and the individual changes in the immune profile.Competing Interest StatementThe authors have declared no competing interest.Clinical TrialNCT04379297Funding StatementThe CON-VINCE Study is funded by the Research Fund Luxembourg (FNR; CON-VINCE) and the André Losch Foundation (Luxembourg).Author DeclarationsAll relevant ethical guidelines have been followed; any necessary IRB and/or ethics committee approvals have been obtained and details of the IRB/oversight body are included in the manuscript.YesAll necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesDue to ethical concerns, supporting data cannot be made openly available. [less ▲]

The Luxembourg Parkinson’s Study: A Comprehensive Approach for Stratification and Early Diagnosis

in Frontiers in Aging Neuroscience (2018), 10

While genetic advances have successfully defined part of the complexity in Parkinson’s disease (PD), the clinical characterization of phenotypes remains challenging. Therapeutic trials and cohort studies ... [more ▼]

While genetic advances have successfully defined part of the complexity in Parkinson’s disease (PD), the clinical characterization of phenotypes remains challenging. Therapeutic trials and cohort studies typically include patients with earlier disease stages and exclude comorbidities, thus ignoring a substantial part of the real-world PD population. To account for these limitations, we implemented the Luxembourg PD study as a comprehensive clinical, molecular and device-based approach including patients with typical PD and atypical parkinsonism, irrespective of their disease stage, age, comorbidities, or linguistic background. To provide a large, longitudinally followed, and deeply phenotyped set of patients and controls for clinical and fundamental research on PD, we implemented an open-source digital platform that can be harmonized with international PD cohort studies. Our interests also reflect Luxembourg-specific areas of PD research, including vision, gait, and cognition. This effort is flanked by comprehensive biosampling efforts assuring high quality and sustained availability of body liquids and tissue biopsies. We provide evidence for the feasibility of such a cohort program with deep phenotyping and high quality biosampling on parkinsonism in an environment with structural specificities and alert the international research community to our willingness to collaborate with other centers. The combination of advanced clinical phenotyping approaches including device-based assessment will create a comprehensive assessment of the disease and its variants, its interaction with comorbidities and its progression. We envision the Luxembourg Parkinson’s study as an important research platform for defining early diagnosis and progression markers that translate into stratified treatment approaches. [less ▲]