This thesis is divided into three parts. The first part of this thesis describes the epidemiology of infections with Clostridioides difficile, meticillin-resistant Staphylococcus aureus and... Show moreThis thesis is divided into three parts. The first part of this thesis describes the epidemiology of infections with Clostridioides difficile, meticillin-resistant Staphylococcus aureus and colistin-resistant Enterobacterales. An important treatment strategy for recurrent C. difficile infections is restoring the disturbed gut microbiota by faecal microbiota transplantation (FMT). The second part discusses the risk of transmission of pathogenic and/or multidrug-resistant bacteria via FMT and procedures to prevent this. Apart from recurrent C. difficile infections, several new potential indications of FMT are being explored. In the third part of this thesis, FMT is explored as a potential new treatment strategy for several neurological disorders, with a main focus on Parkinson’s disease. Show less
Degenerative diseases of the nervous system, such as Alzheimer's, Parkinson's and ALS, are severe, progressive and ultimately fatal. Most existing drugs for these neurodegenerative diseases only... Show moreDegenerative diseases of the nervous system, such as Alzheimer's, Parkinson's and ALS, are severe, progressive and ultimately fatal. Most existing drugs for these neurodegenerative diseases only temporarily relieve symptoms, increase mobility or relieve pain, but do not slow disease progression.This dissertation describes a method to efficiently carry out the development of new drugs that could inhibit disease progression in neurodegenerative diseases. Namely, by using pharmacodynamic biomarkers. These are signaling substances to measure the magnitude of a drug response.These biomarkers can be used in early clinical-pharmacological studies in healthy volunteers or small groups of patients to select the best drug candidates and their expected therapeutic doses as early as possible in the development stage. This helps to make informed choices to advance a potential new drug into large and expensive phase 2 and 3 (registration) studies, or conversely to discontinue development of a non-potential drug as early as possible. This biomarker method was applied in this dissertation to investigate 2 new drugs that could potentially slow disease progression in Alzheimer's and ALS (a RIPK1 inhibitor) or Parkinson's disease (a LRRK2 inhibitor). The research results from multiple early clinical-pharmacological studies in healthy volunteers and patients described in this thesis form the basis for larger phase 2 and 3 follow-up studies that have now been initiated with ALS patients and Parkinson's disease patients. Both with the goal of confirming whether these agents can indeed slow disease progression, which would represent a major breakthrough in the treatment of these conditions. Show less
Parkinson's disease is the second most common neurodegenerative disease in the world. One of its symptoms is the loss of dopaminergic neurons in the substantia nigra pars compacta. A number of... Show moreParkinson's disease is the second most common neurodegenerative disease in the world. One of its symptoms is the loss of dopaminergic neurons in the substantia nigra pars compacta. A number of phenotypes, including the aggregation of misfolded proteins, mitochondrial dysfunction, and neuroinflammatory chemicals released by microglia and activated astrocytes, may all play a role in its pathogenesis.Due to the multisystemic nature of Parkinson's disease, novel tools for developing mechanistic models that simulate its pathogenic processes have been proposed. Furthermore, as the amount of information in biological databases grows and the cost of omics experiments decreases, methods for integrating different types of biological data have become essential for increasing the level of detail in mechanistic models of biological systems.Constraint-based modelling is a valuable tool in bioengineering and biomedicine. It is used to estimate the reaction flux in a metabolic network. The constraints represent essential characteristics of a biological system, including connectivity between metabolites and reactions, thermodynamics, maximum and minimum flux rates, and the steady-state.This thesis presents studies and tools for integrating various types of specific information to genome-scale models used in constraint-based modelling. In addition, is presented the iDopaNeuro default models, genome-scale models of a culture of dopaminergic neurons derived from induced pluripotent stem cells. Show less
This thesis focusses on the further unravelling of one of the mechanisms involved in developing Parkinson's disease: the GBA1 gene, encoding the lysosomal enzyme GCase. Several questions are... Show moreThis thesis focusses on the further unravelling of one of the mechanisms involved in developing Parkinson's disease: the GBA1 gene, encoding the lysosomal enzyme GCase. Several questions are addressed: How prevalent are mutations in this gene in the Netherlands and does it affect disease onset (chapter 2 and 5)? What methodological challenges accompany the sequencing of this gene (chapter 3 and 4)? What biomarkers may be used in clinical trials targeting GCase (chapter 6)? And what are the effects of the novel GCase activator LTI-291, when first administered to healthy volunteers (chapter 7) and to GBA-PD patients (chapter 8)? Show less
Neurodegenerative diseases, including Parkinson’s disease (PD), are increasing in prevalence due to the aging population. Despite extensive study, these diseases are still not fully understood and... Show moreNeurodegenerative diseases, including Parkinson’s disease (PD), are increasing in prevalence due to the aging population. Despite extensive study, these diseases are still not fully understood and the lack of personalised treatment options that can target the cause of the diseases, rather than the symptoms, has led to a greater demand for improved disease understanding, therapies and diagnostic procedures. In this thesis, we use systems biology approaches to construct disease-specific models intended for biomarker discovery, therapeutic treatment strategy identification and drug repurposing in PD. Systems biology is a mathematical field of research that analyses biological systems via construction of a computational model using experimental data. This is achieved by integration of omics data, including genomics, proteomics, transcriptomics and metabolomics. A specific approach used to identify the physico- and biochemical bounds within a biological system is constraint-based modelling, which requires the input of absolute quantitative metabolomics data. To improve our absolute quantitative coverage of the metabolome, we developed and improved new quantitative metabolomics methods using a targeted mass spectrometry workflow to obtain data intended to be integrated into constraint-based metabolic models for the study of PD. Show less
Neurodegenerative diseases are hallmarked by protein inclusions and cell loss in disease-related brain regions, but the molecular mechanisms that lead to the pathological and symptomatic hallmarks... Show moreNeurodegenerative diseases are hallmarked by protein inclusions and cell loss in disease-related brain regions, but the molecular mechanisms that lead to the pathological and symptomatic hallmarks of neurodegeneration are still not fully understood. In this thesis, we make use of bioinformatics approaches to analyze a high-resolution spatial gene expression atlas of the healthy human brain generated by the Allen Institute of Brain Science. Spatial transcriptomics allows examining the molecular and functional organization of the human brain and can be combined with neuroimaging data to identify brain regions and anatomical structures that are vulnerable to cell loss in neurodegenerative diseases. By combining both data modalities, we examined healthy molecular functions in brain regions associated with disease vulnerability based on neuroimaging features, namely gray matter loss within brain networks in individuals with Parkinson’s disease, Huntington’s disease, and individuals at risk of schizophrenia. With this thesis, we have shown that by applying data-driven computational methods we can explore the whole genome and find gene expression patterns informative of regional brain vulnerability in neurodegenerative diseases. Our methods can similarly be applied to unravel the molecular mechanisms in other neurodegenerative diseases, and potentially even reveal shared mechanisms between neurological disorders. Show less
This thesis is divided into to two parts. The first part investigates the effects of the pharmaceutical gamma-hydroxybutyrate (GHB), also known as sodium oxybate (Xyrem), in various clinical... Show moreThis thesis is divided into to two parts. The first part investigates the effects of the pharmaceutical gamma-hydroxybutyrate (GHB), also known as sodium oxybate (Xyrem), in various clinical populations, including individuals with Parkinson’s disease. Most of research in part one investigates GHB in those with the condition of narcolepsy. The effects of GHB on sleep parameters, including sleep quality, is a key focus point. Other chapters explore the hormonal phenotype of narcolepsy and the impact GHB has on the hormones leptin and ghrelin in both narcolepsy and health controls. Gamma-hydroxybutyrate has a history of abuse and know abuse liability. Chapter 5 in this thesis explores the how illicit GHB and Xyrem differ in their abuse potential and incidence. Part two of the thesis focuses on how various aspects of lifestyle influence metabolism and indicators of health status. In Chapter 9, eating behavior is evaluated in response to ecologically relevant amounts of sleep loss common experienced by average people in the modern world. In Chapter 10, we explore how health young adults respond to a four-day, Paleolithic theory-themed nature trip in the German countryside. Show less
In this thesis, longitudinal analyses have been performed on the PROPARK-Cohort, a hospital-based cohort of 421 patients followed for a period of five years. The main focus of this thesis was... Show moreIn this thesis, longitudinal analyses have been performed on the PROPARK-Cohort, a hospital-based cohort of 421 patients followed for a period of five years. The main focus of this thesis was to determine which predictors and associated factors contributed to the development of certain non-motor symptoms in Parkinson’s disease (PD). Strengths of our cohort study include the length of the follow-up period, broad clinical characterization, limited loss-to-follow-up and the large cohort size. The following non-motor symptoms have been addressed in this thesis: psychosis (hallucinations), dementia, excessive daytime sleepiness (EDS), insomnia, depression and anxiety. We found that while certain non-motor symptoms are inherent components of PD that increase in severity as the disease progresses, others symptoms such as excessive daytime sleepiness are inarguably caused by antiparkinsonian medication. For the future, we hope to see more longitudinal data on the disease progression in PD from large cohorts. Knowledge from longitudinal studies does not only contribute to more insight in the underlying pathobiology of PD, but it could also help the caregiver to monitor patients with particular risk factors more closely and adjust treatment if necessary. Show less
Proteins are essential for organisms and participate in virtually every process within cells. Knowledge about the structure of proteins provides crucial information about their function in... Show moreProteins are essential for organisms and participate in virtually every process within cells. Knowledge about the structure of proteins provides crucial information about their function in biological mechanisms. In determining the structure of proteins with biophysical approaches, electron paramagnetic resonance (EPR) is rapidly gaining ground. The aim of this thesis is to provide insight in how broad the application of EPR can be to study proteins, in particular those which are difficult if not impossible to study with other approaches. The focus of this thesis is to investigate the aggregation and misfolding of intrinsically disordered proteins and to determine the structure of disordered parts of proteins with EPR. Specifically, the amyloid β (Aβ) peptide, the α-synuclein (αS) protein, and the light-harvesting protein CP29 are studied. Show less
Falls in Parkinson__s (PD) and Huntington__s disease (HD) are common. 50 % of moderately affected PD patients sustained two or more falls during a prospective follow-up of 6 months. During a 3... Show moreFalls in Parkinson__s (PD) and Huntington__s disease (HD) are common. 50 % of moderately affected PD patients sustained two or more falls during a prospective follow-up of 6 months. During a 3 month period 40 % of HD patients reported one or more fall. Many falls resulted in minor injuries and 42 % of PD patients reported a fear of future falls. A different study on quality of life in PD showed that quality of life scores were significantly related to fear of falling in PD. In order to predict future falls several clinical tests and risk factors were studied. However, it proved difficult to identify future fallers and asking for prior falls was the best predictor of falls in the near future in PD. Analysis with quantative measurements in HD patients showed that an increased medio lateral trunk sway and a decreased stride length were associated with an increased fall risk. Based on the findings in these studies and on a literature study, the thesis concludes with a proposal for a multidisciplinary intervention program to prevent falls in Parkinson__s disease. Show less
The general aim of this thesis was to assess the effectiveness of a standardized psychosocial education program. The first studies of this thesis were aimed to assess the effectiveness of the... Show moreThe general aim of this thesis was to assess the effectiveness of a standardized psychosocial education program. The first studies of this thesis were aimed to assess the effectiveness of the Patient Education Program for Parkinson__s disease (PEPP), as the original program was directed at Parkinson__s disease. Thereafter, it was aimed to assess the program__s feasibility in other diseases. A second step in the thesis was an evaluation of the feasibility of the program adapted to a new disease-specific form for Huntington__s disease (PEP-HD). The third step was to evaluate a generic form of the program in a heterogeneous group of patients with chronic diseases and co-morbid psychiatric problems (PEP-CD). Show less
In many countries physiotherapy is often prescribed to PD patients, somewhere in the course of the disease. However, information about the use and efficacy of physiotherapy in PD is sparse, often... Show moreIn many countries physiotherapy is often prescribed to PD patients, somewhere in the course of the disease. However, information about the use and efficacy of physiotherapy in PD is sparse, often lacking. Therefore, the aims of this thesis are: (a) to gain better insight into the use and merits of physiotherapy for patients with PD and (b) to take a step forward in obtaining evidence-based physiotherapy for patients with PD. As a first step in this process, the efficacy of physiotherapy in PD was evaluated by means of a systematic review (Chapter 2). Secondly, the quality and quantity of current physiotherapy care in PD was evaluated by means of questionnaires sent to patients with PD and their physiotherapists (Chapter 3). Given the frequent use of physiotherapy and the lack of PD-specific expertise amongst therapists, an evidence-based guideline with practice recommendations was developed (Chapter 4). Next, we wished to examine how effective __best practice__ physiotherapy (as described in this new guideline) is for patients with PD. According to EBM recommendations, the results of an RCT provide the highest level of evidence. Therefore, we designed an RCT. To assess the feasibility of this RCT, we first performed a pilot RCT (Chapter 5). The goals of this pilot study were to examine the recruitment rate of patients, to determine the feasibility of the proposed outcome measures, to evaluate the new guideline as a tool to standardise the intervention within the experimental group and to estimate the effect size of the intervention in order to adequately power the RCT. Based on the results of this feasibility study, steps were taken to optimise two promising outcome measures: the Parkinson Activity Scale, evaluating limitations in ADL, and the Patient Specific Index, a patient preference outcome scale (Chapters 6 and 7). At the same time, the ParkinsonNet concept was developed as a novel approach to further improve the quality of physiotherapy in PD ParkinsonNet aims to improve PD-specific expertise among allied health professionals, to improve the referrals to physiotherapy by neurologists and to enhance communication between allied health professionals and neurologists. We then designed a trial to evaluate the implementation process this new ParkinsonNet concept, as well as the possible health benefits and associated costs (Chapter 8). Finally, an overview of the evolution of physiotherapy in PD was made (Chapter 9), which are presented with future challenges (Chapter 10). Show less
Parkinson__s disease (PD) is an age-related neurodegenerative disorder. Pharmacotherapy is the first line symptomatic treatment of this neurological disease. Currently Levodopa (L-DOPA) is still... Show moreParkinson__s disease (PD) is an age-related neurodegenerative disorder. Pharmacotherapy is the first line symptomatic treatment of this neurological disease. Currently Levodopa (L-DOPA) is still considered the drug of first choice, but its possible neurotoxicity and the induction of movement disability after chronic use demand for alternative therapies. An attractive alternative is the use of (semi-)synthetic dopamine agonists. It has been suggested that continuous dopamine receptor stimulation is the best symptomatic treatment of Parkinson__s disease. Therefore the administration of dopamine agonists in a continuous, well-controlled manner by transdermal iontophoresis is an attractive therapeutic strategy in the symptomatic treatment of PD. This dissertation describes the administration of a series of dopamine agonists across the skin using iontophoresis. With iontophoresis a small current is applied across the skin to enhance the transdermal transport of charged molecules. With transdermal iontophoresis a continuous drug administration is achieved. And by adjusting the applied current density it is possible to titrate the dose to the requirements of the patient. In addition, continuous administration results in a continuous stimulation of the dopamine receptors in the striatum. These results demonstrate that transdermal iontophoresis of dopamine agonist is a promising method for the symptomatic treatment of PD. Show less
Parkinson__s disease is a progressive neurodegenerative disease, which is composed of many components, each caused by interplay of a number of genetic and nongenetic causes. As the blood-brain... Show moreParkinson__s disease is a progressive neurodegenerative disease, which is composed of many components, each caused by interplay of a number of genetic and nongenetic causes. As the blood-brain barrier (BBB) is a key player in the relationship between plasma and brain pharmacokinetics, the influences of disease states on BBB functionality in the various stages of the disease is important in order to judge on drug effects. This warrants a systems pharmacology approach to the development of novel drug treatments of Parkinson__s disease. Animal models of disease are an essential asset in this research. The research described in this thesis shows that the intracerebral rotenone rat model is a chronic and progressive animal model for Parkinson__s disease, displaying alpha-synuclein immunoreactivity and aggregation in several cases. The model has also shown that no changes were found in passive BBB permeability, nor in BBB transport modes of L-DOPA. However, a diseased condition was present as indicated by the clear effect of rotenone on the levels and elimination rates of DOPAC and HVA in brain that provided information on decreased dopamine concentrations at the diseased brain side. Altogether, it can be concluded that the intracerebral rotenone rat model is an animal model which is suitable as a tool in systems pharmacology research on Parkinson__s disease. Show less
The thesis “Non-motor symptoms in Parkinson’s disease” is part of the PROPARK study, a longitudinal cohort study of approximately 400 patients with Parkinson’s disease (PD), who are profiled on... Show moreThe thesis “Non-motor symptoms in Parkinson’s disease” is part of the PROPARK study, a longitudinal cohort study of approximately 400 patients with Parkinson’s disease (PD), who are profiled on genotype, phenotype, disability, and global outcomes of health, using valid and reliable assessment instruments for PD. The aims of this thesis were to characterize the non-motor domains important in PD such as olfactory, autonomic, sleep, cognitive, and psychiatric problems. Additionally, their relations with other domains of the disease were evaluated on a cross-sectional level, as well as their impact on disability and health-related quality of life. Furthermore, the phenotypic characteristics of mutation carriers in the cohort were evaluated. The most important conclusions from this thesis are: 1. Non-motor symptoms are frequently present in patients with PD 2. Non-motor symptoms are related to each other 3. Non-motor symptoms greatly influence quality of life in patients with PD The results as described in this thesis will serve as guideline for future research which will be aimed at underlying disease mechanisms. Show less
The first part deals with the hypothalamic hypocretin system in disorders that are accompanied by narcolepsy-like sleep disturbances, i.e. Prader-Willi Syndrome, Parkinson__s Disease and Huntington... Show moreThe first part deals with the hypothalamic hypocretin system in disorders that are accompanied by narcolepsy-like sleep disturbances, i.e. Prader-Willi Syndrome, Parkinson__s Disease and Huntington__s Disease. To determine whether the hypocretin system is affected in these disorders, the total number of hypocretin neurons was determined using quantitative techniques in post-mortem human hypothalami. The reason why hypocretin neurons disappear in narcolepsy is still a mystery. A putative autoimmune aetiology has been hypothesized, but a screening for autoantibodies and a n=1 trial with intravenous immunoglobulins yielded no unequivocal results in favor of this hypothesis. In the second part, the consequences of hypocretin deficiency in narcoleptic patients are explored, focussing on vigilance, metabolism and the autonomic nervous system and skin temperature regulation. The ability of a specific neuropsychological test to measure vigilance as a severity indicator for narcolepsy is explored. Two possible causes for the obesity commonly seen in narcolepsy are a decreased basal metabolic rate and a changed autonomic tone. To assess the influence of hypocretin deficiency on skin temperature regulation, thermoregulatory profiles of the proximal and distal skin of narcoleptic subjects were compared to profiles of healthy controls during a daytime sleep registration. Show less
