In today__s world, more people die from complications of overweight than from underweight. But not all individuals are equally prone to develop metabolic complications, such as obesity and insulin... Show moreIn today__s world, more people die from complications of overweight than from underweight. But not all individuals are equally prone to develop metabolic complications, such as obesity and insulin resistance. This thesis focuses on the differences in the energy and fatty acid metabolism that play a role in the susceptibility for metabolic complications. We have investigated certain existing associations between genetic clues and a disturbed energy metabolism, in order to construct a more refined mechanism of action for this genetic association. This knowledge could be used to more precisely target the causal proteins and pathways involved in the development of obesity. We have also investigated the role of fatty acid metabolism in the fat tissue of obese humans and mice. In this way, we have found a direct link in both humans and mice between fatty acids and inflammation, which is relevant for metabolic diseases such as obesity and insulin resistance. Show less
Nearly one quarter of the world__s population is infected with helminth parasites. A common feature of helminth infections is the manifestation of a type 2 immune response, characterized by T... Show moreNearly one quarter of the world__s population is infected with helminth parasites. A common feature of helminth infections is the manifestation of a type 2 immune response, characterized by T helper 2 (Th2) cells. In addition to their involvement in anti-helminth immunity, recent studies have shown that components of the type 2 immune responses can have additional functions. For example, recent evidence indicates that multiple facets of the type 2 immune response can regulate tissue-specific metabolic processes and whole-body nutrient homeostasis, and protect against insulin resistance. In this work we use omega-1, a glycosylated RNase excreted from Schistsoma mansoni eggs with strong Th2-inducing capacities, to study the requirements that equip DCs for Th2 skewing. In addition, we analyse the effect of chronic S. mansoni infection and administration of S. mansoni-derived egg antigens on metabolic homeostasis in diet-induced obese mice. Elucidating how helminths generate Th2 responses and contribute to metabolic homeostasis will not only shed light on the mechanisms that promote control of parasite infection, but may provide valuable leads for the development of pharmaceutical agents for the treatment of metabolic disorders. Show less
Depression and cardiovascular disease (CVD) are among the most prevalent health problems worldwide, with a significant burden of disease. Both conditions are associated and thought to be mediated... Show moreDepression and cardiovascular disease (CVD) are among the most prevalent health problems worldwide, with a significant burden of disease. Both conditions are associated and thought to be mediated by the metabolic syndrome (MetSyn), a cluster of cardiovascular risk factors (waist circumference, blood sugar, cholesterol, triglycerides, blood pressure) and related parameters (BMI, waist-hip-ratio and LDL-cholesterol). Better insights in this association are important in order to better prevent and treat both conditions. This thesis focuses on the association between depression and metabolic disturbances. The results show that there is a significant and longitudinal and bidirectional association between depression and obesity, which is most pronounced among those with a clinical diagnosis depression. When subjects are approached not based on the presence or absence of the diagnosis, but based on the most prevalent symptoms, results show that only __Somatic Arousal__ symptoms (palpitations, dizziness, tension, shortness of breath) are associated with most MetSyn components. Comparing depressed inpatients to depressed outpatients, inpatients show more adverse metabolic disturbances in the lipid-spectrum, while blood pressure is more favorable. Further, inpatients show higher cortisol levels, which are considered to be a measure of the HPA-axis, an important stress-system in the onset and natural course of depression. Show less
Gast, K.B.; Heijer, M. den; Smit, J.W.A.; Widya, R.L.; Lamb, H.J.; Roos, A. de; ... ; NEO Study Grp 2015
In this thesis we examined several effects of fasting in lean and obese individuals. As expected, both the hormonal response as well as the metabolic shift from glucose towards lipid oxidation was... Show moreIn this thesis we examined several effects of fasting in lean and obese individuals. As expected, both the hormonal response as well as the metabolic shift from glucose towards lipid oxidation was impaired in obese individuals. At baseline, mitochondrial protein content in skeletal muscle of obese subjects was significantly reduced compared to lean individuals. We assessed the neuronal response to fasting by fMRI scanning. We found a different neuronal response to fasting between lean and obese individuals in terms of functional connectivity between the hypothalamus and respectively the dACC and insula. Since these regions are part of the saliency network, these differences may reflect distinct perception of calorie imbalance between lean and obese subjects. The effects of fasting on sympathetic tone (estimated by heart rate variability) were studied. Our data suggests that fasting decreases sympathetic tone in lean subjects, whereas it increases sympathetic activity in obese individuals. Weight loss in obese individuals increased HRV parameters that reflect the postprandial sympathetic tone. Finally, we studied the effects of fasting in the presence and absence of food-odors since this has been shown to reduce the fasting-induced increase in life span in fruit flies __ no differences were found in our human subjects. Show less
