This thesis has studied several modalities how to increase the organ utilisation rate. The results in this thesis indicate that the acceptance of kidneys with acute kidney injury stage 1 or 2 will... Show moreThis thesis has studied several modalities how to increase the organ utilisation rate. The results in this thesis indicate that the acceptance of kidneys with acute kidney injury stage 1 or 2 will significantly contribute to the donor pool as AKI kidneys have comparable outcomes and should therefore not be discarded. Clinically relevant biomarkers such as cell-free unmethylated-INS DNA, FMN, GSN, IGFBP3 and IGF2R were identified or explored in the first part of this thesis and may, if analysed and/or validated thoroughly, contribute to a better assessment of organ viability supporting the justified decision whether to accept or decline the donor organ.The second part of this thesis describes different aspects of the organ preservation technique of abdominal normothermic regional perfusion (aNRP). This relatively new machine perfusion technique has been shown to be feasible and safe, however, consensus regarding assessment parameters during perfusion, protocols and outcome measurements is still lacking. Despite of an inspiring surgical enthusiasm and keeninterest to accept this modality as a new standard, a randomised clinical trial is still required and entirely ethically justifiable in order to scientifically demonstrate superiority of this method for each individual abdominal organ comparing it to other successful (ex-situ) preservation and perfusion strategies. If aNRP can be shown to obtain better post transplantation outcomes whilst increasing organ utilisation, it may be the least complex and most cost-effective strategy in organ preservation. On the other hand, aNRP will only be used in DCD donors. As such, uncertainty regarding the quality of higher risk organs from DBD donors will still be evaluated ex-situ during cold and/or warm machine perfusion with the potential to repair or even regenerate injured organs and making them ‘transplantable’ again. Show less
This thesis describes a set of excitability measurements -transcranial magnetic stimulation (TMS) combined with electromyography (EMG) and electroencephalography (EEG), nerve excitability threshold... Show moreThis thesis describes a set of excitability measurements -transcranial magnetic stimulation (TMS) combined with electromyography (EMG) and electroencephalography (EEG), nerve excitability threshold tracking (NETT), and muscle velocity recovery cycles (MVRC)- and the applicability of these tools in early phase clinical drug development. We validated the biomarkers in healthy subjects with registered drugs and showed that the measurements are all repeatable and sensitive to pharmacological effects, even in a small number of subjects. Furthermore, we have evaluated effects of a novel AMPA-positive allosteric modulator with TMS-EMG/EEG, and a first-in-class skeletal muscle-specific chloride channel (ClC-1) inhibitor with MVRC, and the findings helped us to confirm proof-of-mechanism of these compounds in healthy subjects. In conclusion, these measurements proved to be valuable pharmacodynamic biomarkers in two drug development programs, encouraging their further use in clinical development of other future drug candidates targeting cortical-, neuronal-, and muscle cell excitability. The use of such clinical pharmacodynamic biomarkers could improve the quality and efficiency of the development process of drugs for e.g. amyotrophic lateral sclerosis, chronic pain, depression, treatment-resistant epilepsy, and neuromuscular diseases. Show less
Bilsen, M.P.; Treep, M.M.; Aantjes, M.J.; Andel, E. van; Stalenhoef, J.E.; Nieuwkoop, C. van; ... ; Lambregts, M.M.C. 2024
Objectives: Urinary tract infection (UTI) is common among older women. However, diagnosis is challenging because of frequent chronic lower urinary tract symptoms, cognitive impairment, and a high... Show moreObjectives: Urinary tract infection (UTI) is common among older women. However, diagnosis is challenging because of frequent chronic lower urinary tract symptoms, cognitive impairment, and a high prevalence of asymptomatic bacteriuria (ASB). Current urine diagnostics lack specificity, leading to unnecessary treatment and antimicrobial resistance. This study aimed to evaluate the diagnostic accuracy of 12 urine biomarkers for diagnosing UTI in older women. Methods: In this case -control study, cases were women >= 65 years with >= 2 new -onset lower urinary tract symptoms, pyuria, and one uropathogen >= 104 CFU/mL. Controls were asymptomatic and classified as ASB (one uropathogen >= 105 CFU/mL), negative culture, or mixed flora. Urine biomarker concentrations were measured through liquid chromatography -mass spectrometry and ELISA. Diagnostic accuracy parameters of individual biomarkers and a biomarker model were derived from receiver operating characteristic curves. Results: We included 162 community -dwelling and institutionalized older women. Five urine inflam- matory biomarkers demonstrated high discriminative ability (area under the curve >= 0.80): interleukin 6, azurocidin, neutrophil gelatinase-associated lipocalin, tissue inhibitor of metalloproteinases 2, and C -X-C motif chemokine 9. Azurocidin exhibited the highest diagnostic accuracy (sensitivity 86% [95% CI 75% -93%] and specificity 89% [95% CI 82%-94%] at 16.7 ng/mmol creatinine). A combined biomarker and pyuria model showed improved diagnostic accuracy in patients with UTI and ASB, compared with pyuria alone. Discussion: We identified several urine biomarkers that accurately differentiated older women with UTI from asymptomatic women, including ASB. These findings represent a potential advancement towards improved diagnostics for UTI in older women and warrant validation in a diverse population. Manu P. Bilsen, Clin Microbiol Infect 2024;30:216 (c) 2023 The Authors. Published by Elsevier Ltd on behalf of European Society of Clinical Microbiology and Infectious Diseases. This is an open access article under the CC BY license (http://creativecommons.org/ licenses/by/4.0/). Show less
This thesis focuses on the outcome to immunotherapy in locoregional and metastatic urothelial cancer and biomarkers in the tumor-immune microenvironment that may inform outcome, ultimately... Show moreThis thesis focuses on the outcome to immunotherapy in locoregional and metastatic urothelial cancer and biomarkers in the tumor-immune microenvironment that may inform outcome, ultimately enhancing cancer immunotherapy. Firstly, we discuss the outcome of urothelial cancer patients treated with checkpoint immunotherapy in the metastatic (Part I) and preoperative setting (Part II). Next, we focus on the UC tumor immune microenvironment (Part III), as this may facilitate the discovery and development of novel cancer immunotherapy as well as predictive biomarkers for immunotherapy response in UC. A comprehensive framework based on tumor- and host-specific parameters to better understand immunotherapy response in UC is also provided (Part III). Show less
Pancreatic cancer is an aggressive cancer associated with a poor prognosis as a large proportion of these patients have locally advanced disease or metastases at the time of diagnosis. Currently... Show morePancreatic cancer is an aggressive cancer associated with a poor prognosis as a large proportion of these patients have locally advanced disease or metastases at the time of diagnosis. Currently onlypatients with localized pancreatic tumors can undergo surgery, which is the cornerstone in thetreatment of pancreatic cancer, whether or not preceded by neoadjuvant (chemo/radio)therapy. To establish the diagnosis, imaging techniques are used, tumor tissue must be obtained, and certain tumor markers can be determined in the blood. During surgery, the tumor must be removed in its entirety to prevent early recurrence. This thesis describes the potential role of tumor markers, which can be determined in the blood, and several experimental optical imaging techniques applied to pancreatic cancer. Show less
De uitkomsten beschreven in dit proefschrift dragen bij aan de bestaande overtuiging dat een verfijndere classificatie voor depressie, op basis van symptoomprofielen en hun mogelijke biologische... Show moreDe uitkomsten beschreven in dit proefschrift dragen bij aan de bestaande overtuiging dat een verfijndere classificatie voor depressie, op basis van symptoomprofielen en hun mogelijke biologische onderbouwing, overwogen dient te worden. Inmiddels wordt adipositas in de dagelijkse praktijk op meer dan alleen het BMI beoordeeld, namelijk ook de tailleomtrek en het lipidenprofiel. Echter, dergelijke aandacht bestaat nog niet voor de heterogeniteit van depressie. Een grotere bewustwording van de verschillende manifestaties van depressie-symptomatologie, die het gevolg kunnen zijn van uiteenlopende pathofysiologische mechanismen, is van essentieel belang. Wanneer een patiënt met depressie een atypisch energie-gerelateerd symptoomprofiel heeft, kan het nuttig zijn om diens metabole biomarkers te controleren om mogelijke ontwikkeling van cardiometabole ziekten te voorkomen. In de klinische praktijk moeten wij ons bij de behandeling van patiënten met depressie ook meer bewust worden van de correlatie tussen symptoomprofielen van depressie en afzonderlijke biologische en klinische manifestaties. Het is cruciaal om goed te kijken naar de symptomen die bij elke patiënt tot uiting komen. De resultaten van dit proefschrift tonen aan dat patiënten met een depressie die atypische energie-gerelateerde depressieve symptomen vertonen, genetisch en klinisch kwetsbaar zijn voor aan insulineresistentie gerelateerde ziekten (namelijk adipositas, metabole ontregelingen en diabetes mellitus type 2). Een gepersonaliseerde aanpak kan behulpzaam zijn in preventie van deze chronische en complexe ziekten. Hierbij dient er rekening gehouden worden met de heterogeniteit van depressie en de associatie tussen atypische energie-gerelateerde symptomen van depressie en deze ziekten. Show less
BackgroundB vitamins such as folate (B9), B6, and B12 are key in one carbon metabolism, which generates methyl donors for DNA methylation. Several studies have linked differential methylation to... Show moreBackgroundB vitamins such as folate (B9), B6, and B12 are key in one carbon metabolism, which generates methyl donors for DNA methylation. Several studies have linked differential methylation to self-reported intakes of folate and B12, but these estimates can be imprecise, while metabolomic biomarkers can offer an objective assessment of dietary intakes. We explored blood metabolomic biomarkers of folate and vitamins B6 and B12, to carry out epigenome-wide analyses across up to three European cohorts. Associations between self-reported habitual daily B vitamin intakes and 756 metabolites (Metabolon Inc.) were assessed in serum samples from 1064 UK participants from the TwinsUK cohort. The identified B vitamin metabolomic biomarkers were then used in epigenome-wide association tests with fasting blood DNA methylation levels at 430,768 sites from the Infinium HumanMethylation450 BeadChip in blood samples from 2182 European participants from the TwinsUK and KORA cohorts. Candidate signals were explored for metabolite associations with gene expression levels in a subset of the TwinsUK sample (n = 297). Metabolomic biomarker epigenetic associations were also compared with epigenetic associations of self-reported habitual B vitamin intakes in samples from 2294 European participants.ResultsEighteen metabolites were associated with B vitamin intakes after correction for multiple testing (Bonferroni-adj. p < 0.05), of which 7 metabolites were available in both cohorts and tested for epigenome-wide association. Three metabolites — pipecolate (metabolomic biomarker of B6 and folate intakes), pyridoxate (marker of B6 and folate) and docosahexaenoate (DHA, marker of B6) — were associated with 10, 3 and 1 differentially methylated positions (DMPs), respectively. The strongest association was observed between DHA and DMP cg03440556 in the SCD gene (effect = 0.093 ± 0.016, p = 4.07E−09). Pyridoxate, a catabolic product of vitamin B6, was inversely associated with CpG methylation near the SLC1A5 gene promoter region (cg02711608 and cg22304262) and with SLC7A11 (cg06690548), but not with corresponding changes in gene expression levels. The self-reported intake of folate and vitamin B6 had consistent but non-significant associations with the epigenetic signals.ConclusionMetabolomic biomarkers are a valuable approach to investigate the effects of dietary B vitamin intake on the human epigenome. Show less
Osteoarthritis (OA) is a prevalent age-related joint disease, determined by diverse changes in pathways maintaining articular cartilage and subchondral bone. This thesis aimed to identify and study... Show moreOsteoarthritis (OA) is a prevalent age-related joint disease, determined by diverse changes in pathways maintaining articular cartilage and subchondral bone. This thesis aimed to identify and study gene networks driving interacting etiopathophysiological OA processes in cartilage and subchondral bone. Hereto, characterization of the molecular landscape of bone and cartilage of OA patients showed 305 genes with similar direction of effect, including IL11 and CHADL. Moreover, to capture biological complexity and decipher underlying OA disease mechanisms a variety of human 3D cartilage and bone organoids models were exploited and a human osteochondral construct-on-a-chip was developed. Herein, we showed that the robust OA risk gene WWP2 may initiate OA, via aberrant responses in hypoxia-associated genes and a decrease in anabolic markers. Additionally we showed, as reflected by upregulation of SPP1 and downregulation of WNT16 in cartilage, that treatment of ex vivo human osteochondral explants with human recombinant IL11 does not necessarily has a beneficial outcome. Finally, to allow implementation of knowledge on diverse OA pathophysiological processes, the potency of circulating miRNAs to report on ongoing OA pathophysiological process in joint tissues was established. Such insights are crucial to stratify respective OA patients that require different therapeutic mode of action, towards precision medicine. Show less
Zande, N.A. van de; Bulk, M.; Najac, C.; Weerd, L. van der; Bresser, J. de; Lewerenz, J.; ... ; Bot, S.T. de 2023
IntroductionStrong evidence suggests a significant role for iron accumulation in the brain in addition to the well-documented neurodegenerative aspects of Huntington’s disease (HD). The putative... Show moreIntroductionStrong evidence suggests a significant role for iron accumulation in the brain in addition to the well-documented neurodegenerative aspects of Huntington’s disease (HD). The putative mechanisms by which iron is linked to the HD pathogenesis are multiple, including oxidative stress, ferroptosis and neuroinflammation. However, no previous study in a neurodegenerative disease has linked the observed increase of brain iron accumulation as measured by MRI with well-established cerebrospinal fluid (CSF) and blood biomarkers for iron accumulation, or with associated processes such as neuroinflammation. This study is designed to link quantitative data from iron levels and neuroinflammation metabolites obtained from 7T MRI of HD patients, with specific and well-known clinical biofluid markers for iron accumulation, neurodegeneration and neuroinflammation. Biofluid markers will provide quantitative measures of overall iron accumulation, neurodegeneration and neuroinflammation, while MRI measurements on the other hand will provide quantitative spatial information on brain pathology, neuroinflammation and brain iron accumulation, which will be linked to clinical outcome measures.MethodsThis is an observational cross-sectional study, IMAGINE-HD, in HD gene expansion carriers and healthy controls. We include premanifest HD gene expansion carriers and patients with manifest HD in an early or moderate stage. The study includes a 7T MRI scan of the brain, clinical evaluation, motor, functional, and neuropsychological assessments, and sampling of CSF and blood for the detection of iron, neurodegenerative and inflammatory markers. Quantitative Susceptibility Maps will be reconstructed using T2* weighted images to quantify brain iron levels and Magnetic Resonance Spectroscopy will be used to obtain information about neuroinflammation by measuring cell-specific intracellular metabolites’ level and diffusion. Age and sex matched healthy subjects are included as a control group.DiscussionResults from this study will provide an important basis for the evaluation of brain iron levels and neuroinflammation metabolites as an imaging biomarker for disease stage in HD and their relationship with the salient pathomechanisms of the disease on the one hand, and with clinical outcome on the other. Show less
There is a pressing need to establish novel biomarkers to predict the progression of thoracic aortic aneurysm (TAA) dilatation. Aside from hemodynamics, the roles of oxygen (O2) and nitric oxide ... Show moreThere is a pressing need to establish novel biomarkers to predict the progression of thoracic aortic aneurysm (TAA) dilatation. Aside from hemodynamics, the roles of oxygen (O2) and nitric oxide (NO) in TAA pathogenesis are potentially significant. As such, it is imperative to comprehend the relationship between aneurysm presence and species distribution in both the lumen and aortic wall. Given the limitations of existing imaging methods, we propose the use of patient-specific computational fluid dynamics (CFD) to explore this relationship. We have performed CFD simulations of O2 and NO mass transfer in the lumen and aortic wall for two cases: a healthy control (HC) and a patient with TAA, both acquired using 4D-flow magnetic resonance imaging (MRI). The mass transfer of O2 was based on active transport by hemoglobin, while the local variations of the wall shear stress (WSS) drove NO production. Comparing hemodynamic properties, the time-averaged WSS was considerably lower for TAA, while the oscillatory shear index and endothelial cell activation potential were notably elevated. O2 and NO showed a non-uniform distribution within the lumen and an inverse correlation between the two species. We identified several locations of hypoxic regions for both cases due to lumen-side mass transfer limitations. In the wall, NO varied spatially, with a clear distinction between TAA and HC. In conclusion, the hemodynamics and mass transfer of NO in the aorta exhibit the potential to serve as a diagnostic biomarker for TAA. Furthermore, hypoxia may provide additional insights into the onset of other aortic pathologies. Show less
How to define the preclinical Alzheimer's Disease state in otherwise healthy elderly. How to best select otherwise healthy elderly for clinical trials participation with a disease modifiying... Show moreHow to define the preclinical Alzheimer's Disease state in otherwise healthy elderly. How to best select otherwise healthy elderly for clinical trials participation with a disease modifiying compound. Difference between healthy elderly and subjects in the preclinical AD stage on biomarker level. Difference in cognitive performance in healthy subjects compared to neurodegenerative disease profiles. Show less
BackgroundTo evaluate the potential of cerebrospinal fluid (CSF) levels of matrix metalloproteinases and tissue-type inhibitors (MMP; TIMP), and ratios of MMPs to TIMPs, to function as biomarkers... Show moreBackgroundTo evaluate the potential of cerebrospinal fluid (CSF) levels of matrix metalloproteinases and tissue-type inhibitors (MMP; TIMP), and ratios of MMPs to TIMPs, to function as biomarkers for sporadic or hereditary cerebral amyloid angiopathy (CAA).MethodsCSF concentrations of the matrix metalloproteinases MMP-2, MMP-9 and MMP-14, as well as the tissue inhibitors of metalloproteinases TIMP-1, TIMP-2 and TIMP-3, were determined using immunoassays. These assays were applied to two, independent study groups of sporadic CAA (sCAA) (n = 28/43) and control subjects (n = 40/40), as well as to groups of pre-symptomatic (n = 11) and symptomatic hereditary Dutch-CAA (D-CAA) patients (n = 12), and age-matched controls (n = 22/28, respectively).ResultsIn the sCAA/control cohorts, inconsistent differences were found for individual MMPs and TIMPs, but MMP-2/TIMP-2 (discovery/validation: p = 0.004; p = 0.02) and MMP-14/TIMP-2 ratios (discovery/validation: p < 0.001; p = 0.04) were consistently decreased in sCAA, compared to controls. Moreover, MMP-14 was decreased in symptomatic D-CAA (p = 0.03), compared to controls. The MMP-14/TIMP-1 (p = 0.03) and MMP-14/TIMP-2 (p = 0.04) ratios were decreased in symptomatic D-CAA compared to controls and also compared to pre-symptomatic D-CAA (p = 0.004; p = 0.005, respectively).ConclusionCSF MMP-2/TIMP-2 and MMP-14/TIMP-2 were consistently decreased in sCAA, compared to controls. Additionally, MMP-14/TIMP-2 levels were also decreased in symptomatic D-CAA, compared to both pre-symptomatic D-CAA and controls, and can therefore be considered a biomarker for sporadic and late-stage hereditary forms of CAA. Show less
Pulmonary function tests (PFTs) play an important role in screening and following-up pulmonary involvement in systemic sclerosis (SSc). However, some patients are not able to perform PFTs due to... Show morePulmonary function tests (PFTs) play an important role in screening and following-up pulmonary involvement in systemic sclerosis (SSc). However, some patients are not able to perform PFTs due to contraindications. In addition, it is unclear how lung function is affected by changes in lung structure in SSc. Therefore, this study aims to explore the potential of automatically estimating PFT results from chest CT scans of SSc patients and how different regions influence the estimation of PFTs. Deep regression networks were developed with transfer learning to estimate PFTs from 316 SSc patients. Segmented lungs and vessels were used to mask the CT images to train the network with different inputs: from entire CT scan, lungs-only to vessels-only. The network trained on entire CT scans with transfer learning achieved an ICC of 0.71, 0.76, 0.80, and 0.81 for the estimation of DLCO, FEV1, FVC and TLC, respectively. The performance of the networks gradually decreased when trained on data from lungs-only and vessels-only. Regression attention maps showed that regions close to large vessels were highlighted more than other regions, and occasionally regions outside the lungs were highlighted. These experiments show that apart from the lungs and large vessels, other regions contribute to PFT estimation. In addition, adding manually designed biomarkers increased the correlation (R) from 0.75, 0.74, 0.82, and 0.83 to 0.81, 0.83, 0.88, and 0.90, respectively. This suggests that that manually designed imaging biomarkers can still contribute to explaining the relation between lung function and structure. Show less
In this thesis the role of anti-nuclear antibodies to function as biomarkers in systemic sclerosis has been evaluated. Respectively, the heterogeneity of the disease, the need for biomarkers and... Show moreIn this thesis the role of anti-nuclear antibodies to function as biomarkers in systemic sclerosis has been evaluated. Respectively, the heterogeneity of the disease, the need for biomarkers and the role of auto-antibodies to function as such, with specific attention for anti-topoisomerase I, have been outlined in this thesis. Show less
Doorn, C.L.R. van; Eckold, C.; Ronacher, K.; Ruslami, R.; Veen, S. van; Lee, J.S.; ... ; TANDEM Consortium 2022
Background Globally, the tuberculosis (TB) treatment success rate is approximately 85%, with treatment failure, relapse and death occurring in a significant proportion of pulmonary TB patients.... Show moreBackground Globally, the tuberculosis (TB) treatment success rate is approximately 85%, with treatment failure, relapse and death occurring in a significant proportion of pulmonary TB patients. Treatment success is lower among people with diabetes mellitus (DM). Predicting treatment outcome early after diagnosis, especially in TB-DM patients, would allow early treatment adaptation for individuals and may improve global TB control.Methods Samples were collected in a longitudinal cohort study of adult TB patients from South Africa (n = 94) and Indonesia (n = 81), who had concomitant DM (n = 59), intermediate hyperglycaemia (n = 79) or normal glycaemia/no DM (n = 37). Treatment outcome was monitored, and patients were categorized as having a good (cured) or poor (failed, recurrence, died) outcome during treatment and 12 months follow-up. Whole blood transcriptional profiles before, during and at the end of TB treatment were characterized using unbiased RNA-Seq and targeted gene dcRT-MLPA.Findings We report differences in whole blood transcriptome profiles, which were observed before initiation of treatment and throughout treatment, between patients with a good versus poor TB treatment outcome. An eight-gene and a 22-gene blood transcriptional signature distinguished patients with a good TB treatment outcome from patients with a poor TB treatment outcome at diagnosis (AUC = 0.815) or two weeks (AUC = 0.834) after initiation of TB treatment, respectively. High accuracy was obtained by cross-validating this signature in an external cohort (AUC = 0.749).Interpretation These findings suggest that transcriptional profiles can be used as a prognostic biomarker for treatment failure and success, even in patients with concomitant DM. Copyright (C) 2022 The Authors. Published by Elsevier B.V. Show less
Background: The aim of this study was to develop a prediction model for 10-year overall survival (OS) after resection of colorectal liver metastasis (CRLM) based on patient, tumour and treatment... Show moreBackground: The aim of this study was to develop a prediction model for 10-year overall survival (OS) after resection of colorectal liver metastasis (CRLM) based on patient, tumour and treatment characteristics.Methods: Consecutive patients after complete resection of CRLM were included from two centres (1992-2019). A prediction model providing 10-year OS probabilities was developed using Cox regression analysis, including KRAS, BRAF and histopathological growth patterns. Discrimination and calibration were assessed using cross-validation. A web-based calculator was built to predict individual 10-year OS probabilities.Results: A total of 4112 patients were included. The estimated 10-year OS was 30% (95% CI 29 -32). Fifteen patient, tumour and treatment characteristics were independent prognostic factors for 10-year OS; age, gender, location and nodal status of the primary tumour, disease-free interval, number and diameter of CRLM, preoperative CEA, resection margin, extrahepatic disease, KRAS and BRAF mutation status, histopathological growth patterns, perioperative systemic chemotherapy and hepatic arterial infusion pump chemotherapy. The discrimination at 10-years was 0.73 for both centres. A simplified risk score identified four risk groups with a 10-year OS of 57%, 38%, 24%, and 12%.Conclusions: Ten-year OS after resection of CRLM is best predicted with a model including 15 patient, tumour, and treatment characteristics. The web-based calculator can be used to inform patients. This model serves as a benchmark to determine the prognostic value of novel biomarkers. (C) 2022 The Author(s). Published by Elsevier Ltd. 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
The studies described in this thesis contribute to the identification of biomarkers for risk stratification in systemic sclerosis (SSc). Luckily, nowadays many SSc prospective cohorts have been set... Show moreThe studies described in this thesis contribute to the identification of biomarkers for risk stratification in systemic sclerosis (SSc). Luckily, nowadays many SSc prospective cohorts have been set up worldwide which allows high-quality research. Given the rarity and the heterogeneity of the disease, relatively large cohorts are needed to draw valuable conclusions. For the studies described in the current thesis, I was able to incorporate data from the Leiden prospective SSc cohort and data from other prospective cohorts in Europe, which made it possible to strengthen the data. In this final chapter, I summarize the main findings of the studies presented in this thesis, put our findings in a broader perspective, discuss future perspectives and formulate research questions that are relevant to assess in the years ahead of us. Show less
Background: Antibodies against mycobacterial proteins are highly specific, but lack sensitivity, whereas cytokines have been shown to be sensitive but not very specific in the diagnosis of... Show moreBackground: Antibodies against mycobacterial proteins are highly specific, but lack sensitivity, whereas cytokines have been shown to be sensitive but not very specific in the diagnosis of tuberculosis (TB). We assessed combinations between antibodies and cytokines for diagnosing TB. Methods: Immuoglubulin (Ig) A and IgM antibody titres against selected mycobacterial antigens including Apa, NarL, Rv3019c, PstS1, LAM, "Kit 1" (MTP64 and Tpx)", and "Kit 2" (MPT64, Tpx and 19 kDa) were evaluated by ELISA in plasma samples obtained from individuals under clinical suspicion for TB. Combinations between the antibody titres and previously published cytokine responses in the same participants were assessed for diagnosing active TB. Results: Antibody responses were more promising when used in combination (AUC of 0.80), when all seven antibodies were combined. When anti-"Kit 1"-IgA levels were combined with five host cytokine biomarkers, the AUC increased to 97% (92-100%) with a sensitivity of 95% (95% CI, 73-100%), and specificity of 88.5% (95% CI, 68.7-97%) achieved after leave-one-out cross validation. Conclusion: When used in combination, IgA titres measured with ELISA against multiple Mycobacterium tuberculosis antigens may be useful in the diagnosis of TB. However, diagnostic accuracy may be improved if the antibodies are used in combination with cytokines. Show less
Kuipers, S.; Overmars, L.M.; Es, B. van; Bresser, J. de; Bron, E.E.; Hoefer, I.E.; ... ; Haitjema, S. 2022
Biological processes underlying cerebral small vessel disease (cSVD) are largely unknown. We hypothesized that identification of clusters of inter-related bood-based biomarkers that are associated... Show moreBiological processes underlying cerebral small vessel disease (cSVD) are largely unknown. We hypothesized that identification of clusters of inter-related bood-based biomarkers that are associated with the burden of cSVD provides leads on underlying biological processes. In 494 participants (mean age 67.6 +/- 8.7 years; 36% female; 75% cardiovascular diseases; 25% reference participants) we assessed the relation between 92 blood-based biomarkers from the OLINK cardiovascular III panel and cSVD, using cluster-based analyses. We focused particularly on white matter hyperintensities (WMH). Nineteen biomarkers individually correlated with WMH ratio (r range: 0.16-0.27, Bonferroni corrected p-values <0.05), of which sixteen biomarkers formed one biomarker cluster. Pathway analysis showed that this biomarker cluster predominantly reflected coagulation processes. This cluster related also significantly to other cSVD manifestations (lacunar infarcts, microbleeds, and enlarged perivascular spaces), which supports generalizability beyond WMHs. To study possible causal effects of biological processes reflected by the cluster we performed a mediation analysis that showed a mediation effect of the cluster on the relation between age and WMH ratio (proportion mediated 17%), and hypertension and WMH-volume (proportion mediated 21%). In conclusion, we identified a cluster of blood-based biomarkers reflecting coagulation, that is related to manifestations of cSVD, corroborating involvement of coagulation abnormalities in the etiology of cSVD. Show less