Overweight and obesity are abnormal or excessive body fat accumulation that presents a risk to health. The World Health Organisation defines overweight and obesity with the Body Mass Index (BMI)... Show moreOverweight and obesity are abnormal or excessive body fat accumulation that presents a risk to health. The World Health Organisation defines overweight and obesity with the Body Mass Index (BMI) classification, which is a measure of a person’s weight in kilograms (kg) divided by the square of height in meters (m2). Overweight is defined as a BMI of 25 kg/m2 or higher, whereas obesity is defined as a BMI of 30 kg/m2 or higher. It is estimated that one of every three individuals in the global population has overweight. The prevalence of obesity is increased threefold from 1975 to 2016, with a faster-growing pace in low- and middle-income countries than high-income countries. One common complication of obesity is the metabolic syndrome, which is defined as the co-occurrence of at least three out of five cardiometabolic abnormalities (abdominal obesity, hypertension, hyperglycaemia, hypertriglyceridemia, and low HDL-cholesterol). The metabolic syndrome is a strong risk factor for type 2 diabetes and cardiovascular diseases, and is considered a pathway from obesity to the cardiometabolic diseases occurrence. Thus, if metabolic syndrome or its components are identified and treated early, type 2 diabetes and cardiovascular diseases may be prevented. In this multi-ethnic global population, it is well-established that different ethnic populations have different cardiometabolic risks. Studies have shown that Asian populations develop cardiometabolic complications earlier at the same amount of adiposity as the Western populations. Show less
The aim of this thesis was to unravel a selection of a multitude of potential causal pathways that may underlie the association between excess body fat and cardiovascular disease, such as... Show moreThe aim of this thesis was to unravel a selection of a multitude of potential causal pathways that may underlie the association between excess body fat and cardiovascular disease, such as adipokines, inflammation, HDL-cholesterol and postprandial triglyceride response, and cholesteryl ester transfer protein (CETP). We showed that hs-CRP and GlycA as measures of inflammation, adiponectin, and leptin are not associated with clinical and subclinical cardiovascular disease in the general population. However, all may be relevant markers of disease risk. Also, postprandial triglyceride excursions, genetically-determined CETP and HDL-cholesterol, while not related with subclinical atherosclerosis in the general population, may be interesting targets to pursue in women and men separately, and in subgroups of individuals at high-cardiovascular risk. Show less
The main objective of this thesis is to improve understanding of the role of helminth infections in the development of insulin resistance (IR), hence Type 2 Diabetes (T2D), in the light of... Show moreThe main objective of this thesis is to improve understanding of the role of helminth infections in the development of insulin resistance (IR), hence Type 2 Diabetes (T2D), in the light of increasing urbanization in Indonesia. Our large-scale cluster-randomized controlled trial was performed in a rural area of Indonesia, which is endemic for soil-transmitted helminth (STH), and has been previously reported to have a low prevalence of IR and T2D. In STH-infected subjects, as assessed by microscopy, 12-month anthelmintic treatment increased IR, which was mediated by an increase in BMI and leptin to adiponectin ratio, as well as reduction in eosinophil count. Next, we also aimed to assess the different metabolic profile between populations living in rural and urban area, and to study the relative protective effect of rural environment to high-fat diet (HFD). In comparison to those living in rural area, individuals living in urban area had higher whole body IR, which was mainly mediated by the higher adiposity and leptin level, which were progressively increased with increased duration of time spent in urban area. Different environmental factors (including past or current exposure to STH) did not seem to affect the metabolic response to HFD intervention, independent from adiposity. 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 evolutionary advantage to conserve energy in the form of adipose issue in order to survive long periods of food shortage in the past, turned into a major health problem in current times of... Show moreThe evolutionary advantage to conserve energy in the form of adipose issue in order to survive long periods of food shortage in the past, turned into a major health problem in current times of plenty. Excess accumulation of body fat, or "obesity", is associated with severely increased co-morbidity and mortality risks and is a global epidemical medical condition which is difficult to manage. The exact pathophysiologic mechanism of obesity remains elusive and various factors such as genetic, social, behavioral and physiological cues are involved in its development. From a biological point of view, obesity might be partly explained by differences in the regulation of energy intake, expenditure and storage (energy homeostasis) between obese and lean individuals. The neuroendocrine system provides a source of humoral messengers, which modulate energy homeostasis. This thesis will focus on changes of the neuroendocrine environment of obese women. First of all, spontaneous diurnal plasma hormone concentrations and secretion of different hormonal systems were studied. Secondly, the effect of weight loss on neuroendocrine perturbations of some of these hormonal axes was evaluated. Finally, the impact of modulation of potential physiological cues (increased circulating FFAs and deficit dopaminergic signaling), which might be involved in the neuroendocrine changes and metabolic alterations, was investigated. Show less
