The global obesity pandemic is one of the most significant long-term challenges for healthcare in the current era. Obesity is strongly associated with disrupted glucose and lipid metabolism, a pro... Show moreThe global obesity pandemic is one of the most significant long-term challenges for healthcare in the current era. Obesity is strongly associated with disrupted glucose and lipid metabolism, a pro-inflammatory state of the immune system, and has a causal role in the development of cardiometabolic diseases. The medical science is challenged to find new targets in the fight against this worldwide silent pandemic.We investigated how the gut microbiota influences local and systemic lipid metabolism and immune system of the host and the relationship to pathophysiology of atherosclerosis. The central question was "Does the gut microbiota have a anti-atherogenic potential?" Our studies have shown that oral administration of the bacterium A. muciniphila positively influences the host's lipid metabolism. In addition, oral administration of this bacterium triggers an anti-inflammatory immune response. These findings suggest that A. muciniphila has anti-atherogenic potential. Furthermore, we provided critical insights into two commonly accepted and widely used research methods in cardiometabolic and microbiome research, namely Bone Marrow Transplantation (BMT) and 16S rRNA sequencing. These insights should be taken into account in the research design and interpretation of the research data when applied. In another study, we demonstrated that the gut microbiota increases the cytokine reactions of immune cells after BMT. This phenotype can be transferred to immune cells of healthy controls through Fecal Microbiota Transplantation, implying that this phenotype is independent of BMT-induced gut damage, leaky gut syndrome, and microbiota-mediated. In summary, our studies show that the gut microbiota has anti-atherogenic potential by playing a causal role in the modulation of lipid metabolism and the host's immune system. Show less
In this thesis, we have addressed two key objectives: 1) to gain more insight in various pathophysiological aspects of cardiometabolic diseases including in the disease proneSouth Asian population,... Show moreIn this thesis, we have addressed two key objectives: 1) to gain more insight in various pathophysiological aspects of cardiometabolic diseases including in the disease proneSouth Asian population, and 2) to study the physiological effects of cold exposure and identify a novel pharmacological approach to directly target BAT. Show less
Aims/hypothesisThe aim of this study was to identify differentially expressed long non-coding RNAs (lncRNAs) and mRNAs in whole blood of people with type 2 diabetes across five different clusters:... Show moreAims/hypothesisThe aim of this study was to identify differentially expressed long non-coding RNAs (lncRNAs) and mRNAs in whole blood of people with type 2 diabetes across five different clusters: severe insulin-deficient diabetes (SIDD), severe insulin-resistant diabetes (SIRD), mild obesity-related diabetes (MOD), mild diabetes (MD) and mild diabetes with high HDL-cholesterol (MDH). This was to increase our understanding of different molecular mechanisms underlying the five putative clusters of type 2 diabetes.MethodsParticipants in the Hoorn Diabetes Care System (DCS) cohort were clustered based on age, BMI, HbA1c, C-peptide and HDL-cholesterol. Whole blood RNA-seq was used to identify differentially expressed lncRNAs and mRNAs in a cluster compared with all others. Differentially expressed genes were validated in the Innovative Medicines Initiative DIabetes REsearCh on patient straTification (IMI DIRECT) study. Expression quantitative trait loci (eQTLs) for differentially expressed RNAs were obtained from a publicly available dataset. To estimate the causal effects of RNAs on traits, a two-sample Mendelian randomisation analysis was performed using public genome-wide association study (GWAS) data.ResultsEleven lncRNAs and 175 mRNAs were differentially expressed in the MOD cluster, the lncRNA AL354696.2 was upregulated in the SIDD cluster and GPR15 mRNA was downregulated in the MDH cluster. mRNAs and lncRNAs that were differentially expressed in the MOD cluster were correlated among each other. Six lncRNAs and 120 mRNAs validated in the IMI DIRECT study. Using two-sample Mendelian randomisation, we found 52 mRNAs to have a causal effect on anthropometric traits (n=23) and lipid metabolism traits (n=10). GPR146 showed a causal effect on plasma HDL-cholesterol levels (p = 2×10–15), without evidence for reverse causality.Conclusions/interpretationMultiple lncRNAs and mRNAs were found to be differentially expressed among clusters and particularly in the MOD cluster. mRNAs in the MOD cluster showed a possible causal effect on anthropometric traits, lipid metabolism traits and blood cell fractions. Together, our results show that individuals in the MOD cluster show aberrant RNA expression of genes that have a suggested causal role on multiple diabetes-relevant traits. Show less
Acute cardiovascular clinical events such as myocardial infarction and cerebral stroke represent the major cause of death in Western societies. These pathologies are primarily resulting from... Show moreAcute cardiovascular clinical events such as myocardial infarction and cerebral stroke represent the major cause of death in Western societies. These pathologies are primarily resulting from atherosclerosis, a progressive condition characterized by the accumulation of lipids, immune cells, and fibrous elements in large arteries. The pathogenesis of atherosclerosis involves complex interactions between a wide variety of cells, including monocytes, macrophages, neutrophils, and lymphocytes. It is essential to identify novel targets for therapeutic application in order to reduce the residual atherosclerotic cardiovascular disease risk in current and future patients. Recent studies have suggested that members of the protein arginine methyltransferase (PRMT) family can potentially serve as novel therapeutic targets for atherosclerosis because of their regulatory role in inflammation and metabolism. To validate the contribution of PRMTs in the progression of atherosclerosis, in the studies presented in this thesis we have investigated the effect of inhibition of PRMT functionality on atherosclerosis susceptibility in established atherosclerotic mouse models.To address the role of PRMTs in atherosclerosis, we therefore made use of specific PRMT inhibitors, i.e. TC-E 5003 for PRMT1 inhibition, TP-064 for PRMT4 inhibition, and GSK3326595 for PRMT5 inhibition, that thus far have primarily been applied in vivo in the context of cancer treatment. Show less
This study assesses the association between sleep duration and plasma lipid profiles in people with diabetes mellitus (DM). Sleep duration data were obtained in 91 patients from the POWER2DM study ... Show moreThis study assesses the association between sleep duration and plasma lipid profiles in people with diabetes mellitus (DM). Sleep duration data were obtained in 91 patients from the POWER2DM study (NCT03588104). The patients were divided in tertiles, based on their sleep duration, and blood samples were obtained at the beginning and after 9 months. Significant differences were found, specifically, patients in Tertile 3 (>= 7.51 h) showed lower plasma levels of high-density lipoprotein cholesterol HDL-c (p < 0.05), apolipoprotein A1 (apo-A1; p < 0.05) and low HDL-c/apo-A1 ratio (p < 0.05). This study shows that sleep duration is associated with plasma lipid profiles in people with DM. Show less
Cholesterol influences many pathways, including serving as precursor for adrenal steroidogenesis. Imbalance of cholesterol levels has been implicated in several diseases including cardiovascular... Show moreCholesterol influences many pathways, including serving as precursor for adrenal steroidogenesis. Imbalance of cholesterol levels has been implicated in several diseases including cardiovascular diseases and its underlying pathology, atherosclerosis. Here we concentrate on the role of a) lipid metabolism, especially high-density lipoprotein (HDL), in the development and regression of atherosclerosis and b) apolipoprotein E in adrenal glucocorticoid (GC) synthesis. We showed the importance of HDL size and functionality on atherosclerotic lesion formation in scavenger receptor-BI (SR-BI) knockout mice. Normalisation of the enlarged HDL particle size phenotype in these mice, trough depletion of phospholipid transfer protein, decreased atherosclerotic susceptibility and, contrary, development of a metabolic syndrome like phenotype. Furthermore, we studied the importance of HDL during regression of existing lesions in hypercholesterolemic apolipoprotein-E (ApoE) knockout mice. Normalizing the hypercholesterolemia resulted in regression of lesions and additional HDL depletion impaired the regression.The specific contribution of lipoprotein fractions to steroidogenesis is unknown. We lowered the (very) large-density lipoprotein fraction in ApoE-KO mice, resulting in a decreased GC output. ApoE is also produced within the adrenal where its local role is unclear. By transplanting an ApoE KO adrenal into an adrenalectomized wild-type mouse we revealed that local ApoE does not impact GC synthesis. Show less
Hua, W.; Dijke, P. ten; Kostidis, S.; Giera, M.; Hornsveld, M. 2020
Metastasis is the most frequent cause of death in cancer patients. Epithelial-to-mesenchymal transition (EMT) is the process in which cells lose epithelial integrity and become motile, a critical... Show moreMetastasis is the most frequent cause of death in cancer patients. Epithelial-to-mesenchymal transition (EMT) is the process in which cells lose epithelial integrity and become motile, a critical step for cancer cell invasion, drug resistance and immune evasion. The transforming growth factor-beta (TGF beta) signaling pathway is a major driver of EMT. Increasing evidence demonstrates that metabolic reprogramming is a hallmark of cancer and extensive metabolic changes are observed during EMT. The aim of this review is to summarize and interconnect recent findings that illustrate how changes in glycolysis, mitochondrial, lipid and choline metabolism coincide and functionally contribute to TGF beta-induced EMT. We describe TGF beta signaling is involved in stimulating both glycolysis and mitochondrial respiration. Interestingly, the subsequent metabolic consequences for the redox state and lipid metabolism in cancer cells are found to be in favor of EMT as well. Combined we illustrate that a better understanding of the mechanistic links between TGF beta signaling, cancer metabolism and EMT holds promising strategies for cancer therapy, some of which are already actively being explored in the clinic. Show less
Janssen, L.G.M.; Nahon, K.J.; Bracke, K.F.M.; Broek, D. van den; Smit, R.; Mishre, A.S.D.S.; ... ; Rensen, P.C.N. 2020
Aims/hypothesis: Brown adipose tissue (BAT) improves energy metabolism by combusting glucose and lipids into heat. Agonism of the glucagon-like peptide-1 receptor (GLP-1R) within the central... Show moreAims/hypothesis: Brown adipose tissue (BAT) improves energy metabolism by combusting glucose and lipids into heat. Agonism of the glucagon-like peptide-1 receptor (GLP-1R) within the central nervous system activates BAT in mice. Moreover, in patients with type 2 diabetes, GLP-1R agonism lowers body weight and improves glucose and lipid levels, possibly involving BAT activation. Interestingly, people from South Asian descent are prone to develop cardiometabolic disease. We studied the effect of GLP-1R agonism on BAT in humans, specifically in South Asians and Europids without obesity or type 2 diabetes.Methods: Twelve Dutch South Asian and 12 age- and BMI-matched Europid nondiabetic men received 12 weeks extended-release exenatide (Bydureon) in this single-arm prospective study. Before and after treatment, BAT was visualized by a cold-induced [F-18]FDG-PET/CT scan and a thermoneutral MRI scan, and resting energy expenditure (REE), substrate oxidation, body composition and fasting plasma glucose and serum lipids were determined. Appetite was rated using a visual analogue scale.Results: Since the effect of exenatide onmetabolic parameters did not evidently differ between ethnicities, data of all participants were pooled. Exenatide decreased bodyweight (-1.5 +/- 0.4 kg, p < 0.01), without affecting REE or substrate oxidation, and transiently decreased appetite ratings during the first weeks. Exenatide also lowered tri-glycerides (-15%, p < 0.05) and total cholesterol (-5%, p < 0.05), and tended to lower glucose levels. Notably, exenatide increased BAT metabolic volume (+28%, p < 0.05) and mean standardized uptake value (+11%, p < 0.05) ([F-18]FDG-PET/CT), without affecting supraclavicular adipose tissue fat fraction (MRI).Conclusions/interpretation: We show for the first time that GLP-1R agonism increases [F-18]FDG uptake by BAT in South Asian and Europid men without obesity or type 2 diabetes. (C) 2020 Elsevier Inc. All rights reserved. Show less
Rozendaal, Y.J.W.; Wang, Y.N.; Hilbers, P.A.J.; Riel, N.A.W. van 2019
BackgroundA positive energy balance is considered to be the primary cause of the development of obesity-related diseases. Treatment often consists of a combination of reducing energy intake and... Show moreBackgroundA positive energy balance is considered to be the primary cause of the development of obesity-related diseases. Treatment often consists of a combination of reducing energy intake and increasing energy expenditure. Here we use an existing computational modelling framework describing the long-term development of Metabolic Syndrome (MetS) in APOE3L.CETP mice fed a high-fat diet containing cholesterol with a human-like metabolic system. This model was used to analyze energy expenditure and energy balance in a large set of individual model realizations.ResultsWe developed and applied a strategy to select specific individual models for a detailed analysis of heterogeneity in energy metabolism. Models were stratified based on energy expenditure. A substantial surplus of energy was found to be present during MetS development, which explains the weight gain during MetS development. In the majority of the models, energy was mainly expended in the peripheral tissues, but also distinctly different subgroups were identified.In silico perturbation of the system to induce increased peripheral energy expenditure implied changes in lipid metabolism, but not in carbohydrate metabolism. In silico analysis provided predictions for which individual models increase of peripheral energy expenditure would be an effective treatment.ConclusionThe computational analysis confirmed that the energy imbalance plays an important role in the development of obesity. Furthermore, the model is capable to predict whether an increase in peripheral energy expenditure - for instance by cold exposure to activate brown adipose tissue (BAT) - could resolve MetS symptoms. Show less
Obesity, type 2 diabetes and cardiovascular diseases are major public health problems. South Asians are specifically at risk for the development of (cardio)metabolic diseases, due to a... Show moreObesity, type 2 diabetes and cardiovascular diseases are major public health problems. South Asians are specifically at risk for the development of (cardio)metabolic diseases, due to a combination of known and unknown risk factors. Since effective long-term treatment strategies are currently lacking, the search for additional risk factors and development of targeted treatment strategies to combat these (cardio)metabolic diseases is warranted. An attractive approach seems to be activation of energy-combusting brown adipose tissue (BAT), which can result in increased energy expenditure and improvement in glucose and lipid metabolism. In this thesis, we aimed to address two key objectives: 1) unravelling the underlying mechanisms that could explain the increased predisposition for metabolic disease in the South Asian population, and 2) identifying novel pharmacological strategies that activate BAT and increase energy expenditure in risk populations, including South Asians and individuals with overweight and prediabetes. The studies described in this thesis have highlighted some novel factors, such as endocannabinoids and angiopoitein-like-protein-4, that might in part explain to unbeneficial metabolic phenotype of South Asians. In addition, novel potential therapeutic strategies were identified to combat metabolic disease, such as treatment with a β3-adrenergic receptor agonist and a dipeptidyl-peptidase-4 inhibitor. Show less
The worldwide prevalence of obesity is steadily increasing. Obesity leads to insulin resistance and atherosclerosis, which are the pathologies underlying type 2 diabetes and cardiovascular disease,... Show moreThe worldwide prevalence of obesity is steadily increasing. Obesity leads to insulin resistance and atherosclerosis, which are the pathologies underlying type 2 diabetes and cardiovascular disease, respectively. Inflammation is an important factor connecting obesity to these disorders, but the exact mechanisms connecting obesity, the immune system, type 2 diabetes and cardiovascular disease are still under investigation. The research described in this thesis was performed 1) to gain more insight into the role of the immune system in obesity, dyslipidemia, insulin resistance and atherosclerosis, 2) to study whether inflammation contributes to the disadvantageous metabolic phenotype of a human population with a particularly high risk to develop type 2 diabetes and cardiovascular disease, and 3) to study the therapeutic potential of decreasing inflammation by pharmacological strategies to reduce obesity and improve glucose and lipid metabolism in pre-clinical models. The studies described in this thesis have increased our understanding of the role of inflammation in adipose tissue function and lipid metabolism during the development of type 2 diabetes and cardiovascular disease. Moreover, novel potential therapeutic strategies were identified to combat obesity, metabolic inflammation and associated metabolic disorders, such as treatment with interferons, salsalate and GPR120 agonists. Show less
The brain is increasingly recognized as the regulator of body homeostasis and as possible treatment target for cardiovascular disease. This thesis further reveals the role of the autonomic nervous... Show moreThe brain is increasingly recognized as the regulator of body homeostasis and as possible treatment target for cardiovascular disease. This thesis further reveals the role of the autonomic nervous system (ANS) in the control of lipid metabolism and inflammation, and identified pathological consequences of disturbed regulation. Part I focuses on regulation of lipid metabolism by the ANS, with special attention for brown adipose tissue (BAT) as an emerging pharmacological target for therapy. We describe novel targets that modulate BAT, both directly (e.g. CB1R) and via the brain (e.g. MC4R, GLP-1R) to show that BAT activation improves dyslipidemia, glucose tolerance and T2D and even atherosclerosis. In addition, we identified the biological clock as an important regulator of BAT function and showed the consequences of disturbed circadian rhythmicity for lipid metabolism. Part II of this thesis describes studies on the regulation of inflammation by the ANS, with focus on the anti-inflammatory reflex. During this reflex, binding of acetylcholine to _7nAChR and subsequent intracellular signaling results in transcriptional repression of pro-inflammatory genes. We investigated the effects of hematopoietic _7nAChR deficiency and the consequences of selective parasympathetic and sympathetic denervation of the spleen for this reflex, and for inflammation and atherosclerotic plaque development. Show less
Aim of this thesis was to investigate pharmacogenetic effects on response to statin treatment and the genetics of lipid metabolism and cardiovascular disease. In chapter 4 the first results of the... Show moreAim of this thesis was to investigate pharmacogenetic effects on response to statin treatment and the genetics of lipid metabolism and cardiovascular disease. In chapter 4 the first results of the Genomic investigation of Statin Therapy (GIST) consortium are presented. We identified and validated two new GWAS loci to be associated with LDL-cholesterol response after statin treatment. In addition, we confirmed two previous identified loci. In chapter 5 we showed that we were not able to identify any loci associated with differential event reduction after statin therapy within the PROSPER study. The results presented in chapter 8 show that even at old age a genetic predisposition to high LDL-cholesterol is a risk factor for mortality. The results of this thesis show that currently the possibilities to personalize statin treatment based on genetic variants is limited. New research methods will hopefully give new opportunities to improve cardiovascular disease treatment and give more insight into the biological mechanisms of statin treatment. Show less
Diepen, J.A. van; Berbee, J.F.P.; Havekes, L.M.; Rensen, P.C.N. 2013
The metabolic syndrome is a multi-component condition that includes obesity hypertriglyceridemia and insulin resistance. The prevalence of the metabolic syndrome is rising world-wide and is... Show moreThe metabolic syndrome is a multi-component condition that includes obesity hypertriglyceridemia and insulin resistance. The prevalence of the metabolic syndrome is rising world-wide and is associated with an increased risk for the development of cardiovascular diseases and type 2 diabetes. In the past decades it has been discovered that obese persons have slightly elevated markers of inflammation in their plasma. This low-grade chronic inflammation, also called metabolic inflammation, is hypothesized to function as the link between the various components of the metabolic syndrome. In this thesis, it is evaluated how alterations in triglyceride (TG) and fatty acid (FA) metabolism and inflammatory pathways interact in the development of obesity and insulin resistance, which are both primary risk factors for the development of type 2 diabetes Show less
In this thesis, the role of the liver and lungs in atherosclerosis development were studied. The liver plays an important role in lipid metabolism and inflammation, the two main processes involved... Show moreIn this thesis, the role of the liver and lungs in atherosclerosis development were studied. The liver plays an important role in lipid metabolism and inflammation, the two main processes involved in atherogenesis. We show that continuous enhanced inflammation in hepatocytes increased the hepatic production of VLDL and aggravated atherosclerosis development in hyperlipidemic APOE*3-Leiden (E3L) mice as compared to control E3L mice. Poor lung function, most commonly caused by chronic obstructive pulmonary disease (COPD), is a risk factor for atherosclerosis development. To this end, we investigated whether elastase-induced alveolar wall destruction, a model for COPD, would worsen atherosclerosis development in E3L mice. No difference in atherosclerotic lesion size was observed between mice after elastase or vehicle instillation, indicating that alveolar destruction per se is not responsible for the increased risk for atherosclerosis in COPD patients. Furthermore, we studied the anti-atherosclerotic effects of resveratrol which can be found in red wine and Asian medicinal herbs. Hyperlipidemic E3L.CETP mice were fed a diet without (control) or with resveratrol, atorvastatin, or both. Resveratrol protected against atherosclerosis development, but did not add to the anti-atherogenic effects of atorvastatin. Finally, the clinical implications and future perspectives of these results are discussed. 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
