Rapid socio-economic growth accelerates urbanization in Indonesia, which changes many aspect of human lives, and potentially affect disease prevalence and outcome. This thesis aims to investigate... Show moreRapid socio-economic growth accelerates urbanization in Indonesia, which changes many aspect of human lives, and potentially affect disease prevalence and outcome. This thesis aims to investigate the impacts of urbanization on human health, especially metabolic health and allergic disease, by incorporating many aspects of scientific investigation. Our cluster-randomized-controlled trial showed that, helminth infection, a characteristic feature of rural areas, and anthelmintic treatment, could significantly affect metabolic profiles and hormones. Thus, the ongoing deworming program in Indonesia require in parallel, monitoring of the metabolic health. Additionally, based on our prospective cohort study and analysis on a large scale nationally representative data, although Indonesian rural populations have relatively better metabolic profiles compared to urban, lifelong residence in rural areas does not protect their community members from adverse metabolic changes due to urbanization. Next, we observed that majority of individuals with diabetes in Indonesia were undiagnosed and untreated, especially in rural populations, which warrants extensive action plan from all related stakeholders. Lastly, high-dimensional data analyses on the systemic and nasal mucosal immune profiles revealed a stronger inflammatory immune responses in the nasal mucosal of Indonesian urban young adults with allergic rhinitis compared to their rural counterparts. Show less
The research described in this thesis has, using the zebrafish as a model system, shed new light on the intricate relationship between TB and DM2, in particular on the role of leptin, SHP-1 and... Show moreThe research described in this thesis has, using the zebrafish as a model system, shed new light on the intricate relationship between TB and DM2, in particular on the role of leptin, SHP-1 and glucocorticoids.Leptin plays an important role during TB infection and has a huge impact on insulin sensitivity in zebrafish larvae. Similarly to what has been observed in the murine model, leptin deficiency in zebrafish increased the bacterial burden and mortality during the infection, leading to hyperglycemia and the development of insulin resistance. In addition, a novel SHP-1/SHP-2 inhibitor, NSC-87877, was shown to represent a promising anti-diabetic drug that can be used for further DM2 research, as it is able to rescue the phenotype of the leptin-deficient zebrafish and to restore glucose transport to the tissues. In contrast to metformin, NSC-87877 can act at very early developmental stages and inhibits the function of SHP-1 and factors that underlay impaired glucose metabolism, whereas metformin is mostly known to improve insulin sensitivity. Additionally, treatment with the glucocorticoid beclomethasone attenuates the metabolic changes associated with the infection, and transcriptional alterations induced by beclomethasone treatment suggest that genes involved in glucose metabolism, insulin and leptin signaling all play an important role in the modulation of the metabolism.Our data show that zebrafish larvae represent an interesting model system to investigate the complex pathology of TB, and the studies described in this thesis in which this model has been used have provided novel insights into the molecular mechanisms underlying wasting syndrome and the possibilities for adjunctive glucocorticoid therapy to alleviate this metabolic state. Show less
In this thesis, I study 1) metabolic alterations in tuberculosis related to wasting syndrome in human patients as well as in rodent and fish animal models. 2) effects of the mutation of the leptin... Show moreIn this thesis, I study 1) metabolic alterations in tuberculosis related to wasting syndrome in human patients as well as in rodent and fish animal models. 2) effects of the mutation of the leptin gene on cachexia and diabetes in rodent and zebrafish animal models. 3) how tuberculosis infection and resulting metabolic reprogramming are dependent on leptin signaling in mice and zebrafish larvae. Show less
In modern society, circadian rhythms and sleep are often disturbed, which may negatively affect health. This thesis examines these associations and focuses on the basic functioning of sleep and the... Show moreIn modern society, circadian rhythms and sleep are often disturbed, which may negatively affect health. This thesis examines these associations and focuses on the basic functioning of sleep and the circadian system in mice and in humans. Circadian rhythms are orchestrated by ~20,000 neurons in the central clock in the suprachiasmatic nuclei (SCN) in the brain. In mice, a complete abolishment of central clock-driven rhythms resulted in obesity and severe hepatic insulin resistance. An attenuation of rhythms resulted in decreased muscle strength, osteoporosis-like bone changes and transient changes in the immune system. In humans, short sleeping obese individuals with a preference for evening activities ("evening chronotypes") had increased cardiovascular risk factors. Their neurocognitive function was often impaired and could be improved with sleep extension. Insufficient sleep was also associated with an increased risk for osteopenia and sarcopenia. Taken together, disrupted circadian rhythms and insufficient sleep associate with a spectrum of unfavorable health outcomes. Studies described in the thesis provide insight in potential strategies to improve rhythms and sleep: by appropriately timed behavior (active behavior during the active phase; rest during the rest phase), light exposure (light during the subjective day; darkness at night) as well as caffeine intake. Show less
Aim of this thesis was to provide evidence for the clinical implication of biomarkers in blood and urine, as well as genetic markers, for the prediction of the severity and course of febrile UTI.... Show moreAim of this thesis was to provide evidence for the clinical implication of biomarkers in blood and urine, as well as genetic markers, for the prediction of the severity and course of febrile UTI. Furthermore, this thesis focused on optimization of antimicrobial treatment of febrile UTI. The main results are: 1. Recent hospitalization, indwelling urinary catheter and especially individual fluoroquinolone (FQ) use are independent risk factors for a FQ-resistant Escherichia coli febrile UTI. 2. Women with febrile UTI, including postmenopausal women and those with comorbidities, can be safely and successfully treated with a 7-day course of oral ciprofloxacin. In men, however, treatment duration should be at least 14 days. 3. Diabetes mellitus does not affect the clinical presentation and course of febrile UTI; concurrent illnesses and higher age of the diabetic population attribute to a more complicated course. 4. MR-proADM more accurately predicts a complicated course of disease than currently available inflammatory biomarkers. Importantly, biomarkers derived directly from host defense mechanisms are not suitable to distinguish between febrile UTI patients with and without bacteremia. 5. MP-TF activity is related to disease severity and bacteraemia in febrile E. coli UTI and may contribute to the prothrombotic state in gram-negative sepsis. Show less
In this thesis, senescence is measured in human populations according to its definition of an increase in the risks of dysfunction, disease, and death with chronological age. Part I of this thesis... Show moreIn this thesis, senescence is measured in human populations according to its definition of an increase in the risks of dysfunction, disease, and death with chronological age. Part I of this thesis investigates how a population__s senescence rate can be measured through the increase in mortality rate with age. Part II of this thesis investigates how senescence can be measured through the increase in morbidity - with a focus on cardiovascular disease - in a non-western population and thus be compared with the senescence process in western populations. Show less
Endothelial injury and repair are most important concepts for our understanding of renal disease and allograft injury. The concept that injury to the endothelium may precede renal fibrosis strongly... Show moreEndothelial injury and repair are most important concepts for our understanding of renal disease and allograft injury. The concept that injury to the endothelium may precede renal fibrosis strongly suggests that interventions to maintain vascular integrity are of major importance for renal function. This thesis focuses on the mechanisms involved in the process of endothelial damage and repair in renal disease, (early) diabetes mellitus (DM) and renal ischemia-reperfusion (I/R) injury. Furthermore, microvascular alterations were assessed, using sidestream darkfield (SDF) imaging and measurement of endothelial dysfunction markers (including angiopoietins), in chronic kidney disease (CKD) and DM patients before and after (pancreas) kidney transplantation. The results of this thesis demonstrate an important role for endothelial damage and repair in renal disease and after transplantation. Both renal I/R and DM induced systemic capillary damage reflected by increased capillary tortuosity by SDF imaging and a dysbalance in angiopoietins. In addition, patients with CKD and allograft rejection after renal transplantation also had systemic microvascular derangements. Transplantation was effective in reversing the systemic microvascular alterations. Complementary use of SDF imaging to measure microvascular tortuosity and the assessment of endothelial dysfunction markers may be useful diagnostic tool for monitoring the microvasculature before and after transplantation. Show less
Model based approaches, integrating physiological parameters or linking exposure with response, are powerful tools to quantify and evaluate the impact of genetic differences that are reflected as... Show moreModel based approaches, integrating physiological parameters or linking exposure with response, are powerful tools to quantify and evaluate the impact of genetic differences that are reflected as variability of drug exposure and/or clinical response(s). This thesis __Pharmacogenomics in Drug Development: Implementation and Application of PKPD Model Based Approaches__ focused on genotype differences in explaining inter-individual variability in drug metabolism and clinical response. Population pharmacokinetic and pharmacodynamic models were developed to evaluate the relationship between exposure differences resulting from UGT2B15 genotype and their effects on both fasting plasma glucose and glycosylated haemoglobin for the type 2 diabetes drug, Sipoglitazar__. The model was used to quantify the optimal dose and regime (Single treatment/genotyped-based or titrated based upon response) for future clinical trials. Evaluating the potential impact of genetic differences early during development is important to appropriately design future clinical studies and to ensure that exposure response relationships for efficacy and safety can be identifed for all genetic subgroups. Ultimately, these model-based approaches can be used to determine if covariate-based dose individualization would be advantageous/beneficial to normalize exposure and minimize variability in clinical outcomes across heterogeneous clinical populations. Show less
In this thesis, we evaluated the acute and more long-term effects of different weight loss strategies; pure calorie restriction by very low calorie diet and gastric banding, versus the drastic... Show moreIn this thesis, we evaluated the acute and more long-term effects of different weight loss strategies; pure calorie restriction by very low calorie diet and gastric banding, versus the drastic surgical procedure Roux-en-Y gastric bypass. Moreover, we found differences between NGT and T2DM subjects at baseline, which enable us to better be able to dissect the subsequent effects of the procedures. To our surprise, and in contrast to previous studies, we observed no additional effect of the RYGB as compared to calorie restriction, on our main outcome parameters: postprandial glucose, insulin and the gut peptide levels three weeks after surgery. Furthermore, both restrictive and RYGB induced weight loss resulted in comparable effects on the lipidome, circulating thyroid hormone levels and the autonomic nervous system. For these outcome parameters, it seems that calorie restriction is the common denominator of the effect of the different weight loss strategies on the short term. Clearly distinct effects of RYGB, however, were seen on bile salt, FGF21 and glucagon levels in response to food intake. Although neither the exact mechanisms, nor the eventual metabolic effect are as yet clear, the gut-liver-pancreas axis may be an important mediator of the effect of the RYGB Show less
Research described in this thesis is based on clinical data obtained through diabetes cardiovascular risk management (DIACARM) project. A clinical protocol founded on the co-operation of the... Show moreResearch described in this thesis is based on clinical data obtained through diabetes cardiovascular risk management (DIACARM) project. A clinical protocol founded on the co-operation of the departments of endocrinology, cardiology, nephrology, radiology and nuclear medicine at the Leiden University Medical Center. This protocol is set to improve medical care at patient and provide more insight into cardiovascular risk stratification in asymptomatic patients with diabetes. The first part of the thesis focuses on the nature of coronary artery disease in diabetes, and its presentation with different imaging modalities. The relation between epicardial adipose tissue and plasma biomarkers with coronary atherosclerosis were investigated. Furthermore, extent and morphology of atherosclerosis are compared in patients with type 1- and type 2 diabetes. In the second part of the thesis the value of non-invasive vascular measurements (carotid intima media thickness, pulse wave velocity) and cardiac imaging techniques were evaluated and compared for risk stratification of coronary artery disease in diabetes. The final part of the thesis describes a novel technique, sidestream dark field imaging, for the assessment of the microcirculation at capillary level. Parameters of microcirculation were shown to have a relation with coronary artery disease in diabetes Show less
This thesis was to combine metabolomics and Chinese medicine (CM) diagnosis to search for biomakers or metabolic profiles to subtype of type 2 diabetes (T2DM). An explorative study of 50 males with... Show moreThis thesis was to combine metabolomics and Chinese medicine (CM) diagnosis to search for biomakers or metabolic profiles to subtype of type 2 diabetes (T2DM). An explorative study of 50 males with pre-diabetes was designed and two subtypes (A and B) could be identified by urine metabolomics. More metabolic disturbances were indicated in subtype B. The effects of rimonabant and a multi-component preparation (SUB885C), both with reported effects of regulating weight and the improvement on metabolic risks, were assessed by lipidomics on ApoE*3Leiden.CETP Mice. A 4-week rimonabant intervention brought a significant weight reduction, but moderate effects on lipid profile. SUB885C was able to produce multiple anti-atherogenic changes in lipids of the mice to improve metabolic parameters. A combined approach of lipidomics, biochemistry and herbal component profiling was used to evaluate the effects of the ginseng roots of 3__6 years on the regulation of dyslipidemia in diabetic Goto-Kakizaki rats. The more than 4 year ginseng proved to be valuable for drug development to regulate lipids. To conclude, the early metabolomics investigations performed in this thesis converged analytical bioscience, clinical approach and the diagnostic perspectives in other health system to provide the systems biology view on the pre-stage of T2DM. Show less
The introduction of systems biology in combination with the profiling of numerous biochemical components (e.g. lipid metabolites, herbal products) enables the study of living systems from a... Show moreThe introduction of systems biology in combination with the profiling of numerous biochemical components (e.g. lipid metabolites, herbal products) enables the study of living systems from a holistic perspective. In this thesis we explored systems biology-based platforms to investigate the therapeutic effects of chemical drugs and herbal medicines on animal models with high-fat diet-induced obesity and genetic manipulated diabetes. The aim of the work was to better understand the working mechanisms of both treatments on metabolic syndrome from a holistic point of view and to evaluate the potentials of __omics__ technologies to this effort. Our results showed that lipidomics approach with appropriate bioinformatics tools are essential to describe the global, dynamic metabolic response of living systems, e.g. from homeostasis via sub-optimal health and ultimately to dysfunction. These studies pointed hints to disco ver lipid biomarkers in relation to health promotion and disease prevention and facilitated the understanding of the complex regulatory mechanisms in humans or animals. Particularly, the introduction of the systems biology view will not only provide in-depth insights into the multi-target synergetic effects (which have hardly been used in modern drug discovery) but also can bridge Chinese Medicine (multi-target therapy) and Western Medicine (molecular pharmacology). Show less
The studies in this thesis contribute to the understanding of the role of the brain in insulin sensitivity. We demonstrate that disturbances in circadian rhythm resulting in alterations in SCN... Show moreThe studies in this thesis contribute to the understanding of the role of the brain in insulin sensitivity. We demonstrate that disturbances in circadian rhythm resulting in alterations in SCN output, can contribute to the development of insulin resistance. We also shown that insulin-stimulated glucose uptake by muscle and insulin-stimulated FA uptake by WAT is in part dependent on insulin action in the brain. These effects of circulating insulin on peripheral organs via the brain are abrogated by high-fat diet. These brain-dependent effects of insulin could reflect a similar situation for other hormones, for instance thyroid hormones. Furthermore, we demonstrate that topiramate improves insulin resistance by restoring insulin sensitivity in the brain, suggesting that therapeutical targets in the brain may offer challenging new approaches to treat insulin resistance of peripheral organs in T2DM. Show less
Overgewicht en obesitas kunnen leiden tot insulineresistentie (type 2 diabetes mellitus) en hyperlipidemie, een risicofactor voor atherosclerose (aderverkalking). Obesitas gaat ook gepaard met de... Show moreOvergewicht en obesitas kunnen leiden tot insulineresistentie (type 2 diabetes mellitus) en hyperlipidemie, een risicofactor voor atherosclerose (aderverkalking). Obesitas gaat ook gepaard met de ontwikkeling van een chronische ontsteking in vetweefsel en lever. Met dit promotieonderzoek laten we met behulp van onderzoek in muizen zien dat ontsteking een belangrijke rol speelt in het metabolisme en transport van vetten. We bekijken ook welk effect dit heeft op de ontwikkeling van atherosclerose en type 2 diabetes. In het eerste deel van dit promotieonderzoek laten we zien dat ontsteking een belangrijke rol speelt in vetmetabolisme en atherosclerose. De ontstekingsremmer aspirine zorgde voor een verlaging van de hoeveelheid vet in het bloed. Activatie van een onsteking in de lever leidde juist tot een verhoging van vet in het bloed, wat de ontwikkeling van atherosclerose in de vaatwand verergerde. In het tweede deel van dit promotieonderzoek bestuderen we het belang van het inflammasoom/caspase-1 complex (betrokken bij ontstekingsprocessen) in obesitas, insulineresistentie en vetmetabolisme. We laten zien dat muizen die een deel van dit eiwit-complex missen, beschermt zijn tegen de ontwikkeling van obesitas en insulineresistentie. Het inflammasoom/caspase-1 complex lijkt daarmee een potentieel target voor de behandeling van obesitas, insulineresistentie en type 2 diabetes. Show less
Obesity is characterized by excessive fat storage and is associated with various diseases like cardiovascular disease (CVD) and type 2 diabetes (DM2), thereby being a serious problem of public... Show moreObesity is characterized by excessive fat storage and is associated with various diseases like cardiovascular disease (CVD) and type 2 diabetes (DM2), thereby being a serious problem of public health. Excessive energy intake is an important cause of obesity since excess energy is primarily stored as fat. The stored fat is mobilized again during fasting in the form of fatty acids (FA). These FA are re-esterified in the liver in triglycerides (TG) that are secreted in VLDL particles to deliver FA to peripheral tissues where they can be used for energy. One of the current views of the cause of diseases related to obesity is the (mis)handling of TG derived FA. Therefore it is important to understand pathways involved in the uptake, distribution, oxidation and storage of TG. In this thesis we have evaluated the effect of different interventions on VLDL-TG metabolism to gain a better understanding of its complex regulation. For these studies we used APOE*3-Leiden (E3L) and E3L.CETP transgenic mice that have a human-like lipoprotein metabolism and respond to lipid-modifying drugs in a ways similar to humans. Show less
Diabetes is taking on epidemic proportions, not only in western society. Via the blood, glucose is transported to the organs in the human body. When a meal is consumed, blood glucose levels rise.... Show moreDiabetes is taking on epidemic proportions, not only in western society. Via the blood, glucose is transported to the organs in the human body. When a meal is consumed, blood glucose levels rise. Insulin is secreted from the pancreas in response to the increased blood glucose levels and lowers blood glucose by increasing glucose uptake in insulin-sensitive tissues. Under conditions of insulin resistance, insulin does not have its full effect resulting in increased blood glucose levels, which left untreated will result in diabetes. Also at the signal transduction level insulin resistance is evident. An important signaling intermediate is protein kinase B (PKB/Akt). Its activity is decreased under conditions of insulin resistance. However PKB/Akt phosphorylates many targets and not all phosphorylation targets have been linked to a specific function. Therefore the aim of the research conducted in the thesis was to examine the role of PKB/Akt phosphorylation target PRAS40 in insulin action. PRAS40 is expressed in insulin sensitive tissues and is phosphorylated in response to insulin. PRAS40 interacts with another component of the insulin signaling cascade: mammalian target of rapamycin. Under conditions of insulin resistance, PRAS40 phosphorylation is decreased and higher expression of PRAS40 has a protective role in insulin resistance. Show less
The aim of the thesis was to provide more insight into the influence of myocardial steatosis on left ventricular function in healthy volunteers and in patients with type 2 diabetes mellitus.... Show moreThe aim of the thesis was to provide more insight into the influence of myocardial steatosis on left ventricular function in healthy volunteers and in patients with type 2 diabetes mellitus. Therefore we developed a reproducible proton magnetic resonance (MR) spectroscopic technique with respiratory motion compensation to study myocardial steatosis. Using these technique, combined with MR imaging to study myocardial function, correlations between myocardial steatosis and left ventricular function were shown in several (patho)physiological conditions. Furthermore, we showed that myocardial triglyceride content is increased in patients with type 2 diabetes mellitus and is an independent predictor of left ventricular diastolic dysfunction. In addition, differential, tissue-specific partitioning of triglycerides and/or fatty acids among non-adipose organs during various diets was shown. Given the obesity and type 2 diabetes mellitus pandemic and the increasing evidence indicating that lipid oversupply to cardiomyocytes plays a role in the development of diabetic cardiomyopathy, therapeutic strategies that target reduction of cardiac lipid overexposure might be beneficial to prevent diabetic cardiomyopathy. Show less
Using newly developed single cell A3243G mutation load assays a novel mechanism of mtDNA segregation was identified in which the multi-copy mtDNA nucleoid takes a central position. Furthermore,... Show moreUsing newly developed single cell A3243G mutation load assays a novel mechanism of mtDNA segregation was identified in which the multi-copy mtDNA nucleoid takes a central position. Furthermore, likely due to low level changes in gene expression, no genes or gene sets could be identified with gene wide expression analysis that would hint to the molecular pathways that are altered upon loss of mitochondrial ATP production as a consequence of A3243G mtDNA mutation. Extensive post-transcriptional adaptation in the form of global translation repression, was however apparent. A comparison between two mtDNA haplotypes indicated, that these presumably neutral sequence variants can affect the nuclear expression program, which tentatively indicates that mtDNA haplotype can affect phenotype. Show less
Nowadays, obesity has reached epidemic proportions globally. It can lead to several chronic diseases, including insulin resistance/type 2 diabetes mellitus. Feeding behaviour is regulated in the... Show moreNowadays, obesity has reached epidemic proportions globally. It can lead to several chronic diseases, including insulin resistance/type 2 diabetes mellitus. Feeding behaviour is regulated in the hypothalamus of the brain by two opposing pathways: NPY/AgRP neurons vs. POMC/CART neurons. In addition, there are numerous peripheral signals, deriving from stomach, gut, pancreas and adipose tissue, that act on the hypothalamus and thereby contribute to the regulation of food intake. The aim of the studies we have performed, was to investigate the effects of some of these neuropeptides and peripheral signals that affect these neuropeptides, on insulin action. Our experiments showed, that NPY can cause insulin resistance, specifically in the liver. The POMC pathway can improve insulin-mediated glucose disposal and does not affect hepatic insulin sensitivity. Therefore, both pathways are not completely opposing each other’s effects, but seem to have a different tissue-specific effect. Experiments with gut hormones like PYY and ghrelin showed that these hormones affect insulin sensitivity as well. Also leptin, and specifically leptin signalling in the brain, was found to be important for insulin sensitivity. In conclusion, this work showed that neuropeptides/hormones that are involved in the regulation of food intake also affect insulin sensitivity. Show less
The scope of the current thesis is to obtain insight in immunological aspects of transplantation and diabetes. This thesis underscores the current concept of collaboration between the innate and... Show moreThe scope of the current thesis is to obtain insight in immunological aspects of transplantation and diabetes. This thesis underscores the current concept of collaboration between the innate and adaptive immune system by showing close interactions between both immune systems. Mannose binding lectin as a major recognition molecule of the lectin pathway and as a key protein of the immune system was studied in relation to its functional characteristics. Appreciating the Jekyll-and-Hyde character of MBL and the fact that MBL serum levels and functionality are under strict genetic control, MBL was studied under distinct pathological conditions. Chapter 2 describes molecular and biological aspects of mannose binding lectin and the interaction of MBL with the adaptive immune system. Chapter 3 focuses on the involvement of MBL in autoimmunity, by studying juvenile type 1 diabetic patients at disease onset. Chapter 4 addresses the role of the liver in production of serum MBL and evaluates the effect of MBL variant alleles on the susceptibility to infection after liver transplantation. Chapter 5 focuses on the effect of the adaptive immune system on islet transplantation, a novel treatment of type 1 diabetes. Show less
