This interventional study is part of a broader research project entitled "Bone Marrow Adipose Tissue in Relation to Bone and Energy Metabolism in Obesity and Type 2 Diabetes Mellitus." The broader project includes both a cross-sectional study evaluating bone marrow adipose tissue and bone marrow mesenchymal stem cells in people with different metabolic and bone disorders and the present dietary intervention study.
The interventional study investigates whether caloric restriction changes bone marrow adipose tissue, bone health, whole-body metabolism, and the molecular and cellular characteristics of bone marrow mesenchymal stem cells in obese non-diabetic premenopausal women. A group of lean healthy premenopausal women will serve as a comparison group.
Participants in the intervention group will undergo an eight-week formula-based very-low-calorie diet using Cambridge Weight Plan products, providing approximately 2.5-3.35 MJ (600-800 kcal) per day, followed by a dietary weight-maintenance phase. Participants will receive nutritional counselling, and dietary adherence, body weight, physical activity, and clinical status will be monitored during scheduled study visits. Clinical and laboratory assessments will be conducted at baseline and after 2, 6, and 12 months.
Assessments will include magnetic resonance imaging and proton magnetic resonance spectroscopy of the lumbar spine to measure the amount and lipid composition of vertebral bone marrow adipose tissue. Bone mineral density and body composition will be measured using dual-energy X-ray absorptiometry, with particular attention to bone mineral density at the total hip and femoral neck. Additional measurements will include body weight, waist and hip circumference, body composition, physical activity, and fasting blood tests evaluating bone turnover, glucose and lipid metabolism, inflammatory markers, hormones, and adipokines.
Bone marrow aspirates and abdominal subcutaneous adipose tissue biopsies will be obtained at baseline and after six months. Bone marrow-derived and adipose tissue-derived mesenchymal stem cells will be examined for changes in cellular composition, gene-expression profiles, metabolic activity, oxidative stress, differentiation capacity, and senescence-related characteristics. Single-cell RNA sequencing will be used to characterize specific bone marrow mesenchymal stem cell subpopulations.
Bone marrow plasma and other biological samples will also undergo metabolomic, lipidomic, and proteomic profiling using high-resolution mass spectrometry. These analyses will be used to identify extracellular molecules and molecular patterns associated with glucose and lipid metabolism, inflammation, cellular senescence, and the response to caloric restriction.
The study aims to determine whether diet-induced weight loss can improve the bone marrow microenvironment and modify vertebral bone marrow fat, bone parameters, and the metabolic and senescent phenotype of mesenchymal stem cells. The findings may help identify imaging, cellular, and molecular markers of obesity-related bone fragility.
Premenopausal women and age-eligible men assigned to either the obese intervention group or the lean control group
Body mass index (BMI) of 30-42 kg/m²
Fasting plasma glucose less than 6.4 mmol/L
Age 25-55 years
Diabetes mellitus
Secondary osteoporosis
History of severe neuropathic disease
Hyperparathyroidism
Parallel
Caloric Restriction
BehavioralParticipants will follow a formula-based very-low-calorie diet (Cambridge Weight Plan) providing approximately 600-800 kcal per day (2.5-3.35 MJ per day) for 8 weeks. This will be followed by a 4-month low-calorie diet phase and subsequently by a weight-maintenance phase. Participants will receive nutritional counselling, and dietary adherence, body weight, physical activity, and clinical status will be monitored during scheduled study visits.
Change From Baseline in Mean L2-L4 Vertebral Bone Marrow Adipose Tissue Proton Density Fat Fraction
Vertebral bone marrow adipose tissue proton density fat fraction will be measured in the L2, L3, and L4 vertebral bodies using the mDIXON Quant MRI sequence. The mean value across the three vertebral bodies will be reported as a percentage.
Change From Baseline in Mean L2-L4 Vertebral Bone Marrow Adipose Tissue Unsaturation Index
The lipid composition of vertebral bone marrow adipose tissue will be measured in the L2, L3, and L4 vertebral bodies using proton magnetic resonance spectroscopy. A prespecified unsaturation index will be calculated from the unsaturated and total lipid signals. The mean value across the three vertebral bodies will be reported.
Change from baseline in BM-MSC and AT-MSC potency, differentiation, senescence, and metabolic adaptation
Change from baseline to Week 24 in characteristics of bone marrow-derived mesenchymal stem cells (BM-MSCs) and adipose tissue-derived mesenchymal stem cells (AT-MSCs). Potency is assessed using the colony-forming unit-fibroblast (CFU-F) assay and proliferation rate. Osteogenic differentiation is assessed by alkaline phosphatase (ALP) activity and expression of ALPL and RUNX2; adipogenic differentiation is assessed by Nile Red staining and expression of ADIPOQ and LEP. Senescence is assessed by senescence-associated β-galactosidase activity and expression of p16INK4a and p21. Metabolic adaptation is assessed by extracellular flux analysis of mitochondrial respiration and glycolytic capacity and by insulin-signaling activation. For each parameter, the outcome is the change from baseline to Week 24, compared between BM-MSCs and AT-MSCs.
Change from baseline in metabolomic and lipidomic profile of bone marrow and plasma
Change from baseline to Week 24 in the metabolomic and lipidomic profiles of bone marrow and plasma. Untargeted and targeted liquid chromatography-mass spectrometry (LC-MS) analyses assess amino acids, organic acids, nucleotides, and intermediates of central carbon metabolism. LC-MS lipidomic analysis assesses fatty acids, phospholipids, sphingolipids, triacylglycerols, and diacylglycerols. For each metabolite and lipid species, the outcome is the change in concentration from baseline to Week 24, compared between bone marrow and plasma.
Change From Baseline in Total Hip Bone Mineral Density
Areal bone mineral density of the total hip will be measured by dual-energy X-ray absorptiometry using a Hologic Horizon A densitometer. Bone mineral density will be reported in grams per square centimeter. Change from baseline will be calculated at Week 24 and Week 48.
Change From Baseline in Lumbar Spine Bone Mineral Density
Areal bone mineral density of the lumbar spine (L1-L4) will be measured by dual-energy X-ray absorptiometry using a Hologic Horizon A densitometer. Bone mineral density will be reported in grams per square centimeter. Change from baseline will be calculated at Week 24 and Week 48.
Change From Baseline in Femoral Neck Bone Mineral Density
Areal bone mineral density of the femoral neck will be measured by dual-energy X-ray absorptiometry using a Hologic Horizon A densitometer. Bone mineral density will be reported in grams per square centimeter.
Change From Baseline in the Abdominal Subcutaneous-to-Visceral Adipose Tissue Ratio
Abdominal subcutaneous adipose tissue and visceral adipose tissue will be quantified at the L3 vertebral level using a breath-hold T1-weighted mDIXON MRI sequence. The ratio of subcutaneous adipose tissue to visceral adipose tissue will be calculated and reported as a unitless ratio. Change from baseline will be calculated separately at Week 24 and Week 48.
Change From Baseline in Total Body Fat Mass Measured by DXA
Total body fat mass will be measured using whole-body dual-energy X-ray absorptiometry with a Hologic Horizon A densitometer. Total body fat mass will be reported in kilograms. Change from baseline will be calculated at Month 6 and Month 12.
Change From Baseline in Bone-Free Lean Mass Measured by DXA
Bone-free lean mass will be measured using whole-body dual-energy X-ray absorptiometry with a Hologic Horizon A densitometer. Bone-free lean mass will be reported in kilograms. Change from baseline will be calculated at Month 6 and Month 12.
Click on the lead sponsor to view all of their trials.
General University Hospital, Prague
Lead sponsor
Czech Academy of Sciences
Collaborator
Ministry of Health, Czech Republic
Collaborator
