In this explorative randomized clinical study, the investigators aim to study metabolic, cellular, and molecular changes that occur during weight loss in obese subjects with and without type 2 diabetes. Using novel "imiomics" (imaging technique using PET/MR bioinformatics) analyses to examine possible metabolic differences between energy restricted diet and gastric by-pass surgery on whole-body and tissue specific insulin sensitivity, glucose tolerance, metabolite and protein profiles, fatty acid metabolism, ectopic fat content, and gene expression in adipose tissue. This study aims to identify novel biomarkers and drug targets for type 2 diabetes as well as validate promising and established biomarkers in an interventional model for improved glucose metabolism.
By using omics platforms such as genomics, proteomics and metabolomics we can have large amount of information about metabolic changes at both tissue and whole body level. In parallel to this, clinical imaging modalities such as Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET) have developed rapidly, allowing for whole-body studies of how different tissues are involved in systemic diseases. Furthermore, new hybrid systems such as integrated PET-MRI provide combined information of human morphology and function. The integration of PET with MRI reduces the radiation dose compared with PET-CT to acceptable levels for metabolic studies. To handle the large amounts of data from these examinations we are currently developing an image analysis concept, "Imiomics", that allows holistic analysis of whole-body imaging data with integration of non-imaging data. In the current study, we plan to use PET-MRI as well as imiomics methodology, together with gold standard methodology to assess insulin sensitivity and glucose tolerance in vivo. We aim to conduct a randomized study (CRUDOS study; Caloric Restriction Using Diet Or Surgery) to study glycometabolic effects before and after gastric bypass surgery and low-calorie diet in subjects at different stages of glucose tolerance (i.e. obese subjects with and without T2D).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
50
Gastric by-pass surgery is expected to achieve a mean weight loss of 7-8kg in 4 weeks, which is similar weight-loss achieved in the other arm (low-caloric diet) during this time period.
Energy restricted diet with a total energy intake of 800-1200kcal/day
Uppsala univeristy hospital
Uppsala, Sweden
RECRUITINGChange in tissue specific glucose uptake measured by euglycemic clamp in PET/MR scanner
Tissue specific assessment of glucose metabolism (18FDG uptake) using in-scanner (integrated PET-MR) insulin clamps.
Time frame: 4 weeks
Metabolite concentrations in plasma
Plasma metabolite concentrations (metabolomics) are assessed by liquid chromatography-mass spectrometry
Time frame: 4 weeks
Gene expression in adipose tissue
Change in gene expression is assessed by microarray (untargeted) messenger ribonucleic acid (mRNA) analyses
Time frame: 4 weeks
Lipoprotein changes in plasma assessed by routine clinical chemistry
Time frame: 4 weeks
Plasma adipokines (e.g. adiponectin) assessed by elisa
Time frame: 4 weeks
Fatty acid composition in plasma assessed by gas chromatography
Time frame: 4 weeks
Changes in plasma protein profile (proteomics) assessed by immunohistochemistry
Time frame: 4 weeks
Epigenetic changes assessed as DNA methylation
Time frame: 4 weeks
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