ABSTRACT
INTRODUCTION: The effect of changes in body weight or insulin resistance on grey matter volume and cortical thickness change are unclear. The present observational study assessed effects of an 8-week weight loss period (≥8% of body weight), and a subsequent 22-month weight maintenance period on grey matter volume and cortical thickness. METHODS: A total of 24 participants (12f/12â¯m; age 52.8⯱â¯10.6â¯years) with overweight/obesity and pre-diabetes were recruited. T1-weighted magnetic resonance imaging was used to determine grey matter volume and cortical thickness at baseline, after the weight loss period and after a medium to high dietary protein weight maintenance period. RESULTS: At baseline, global grey matter volume was inversely associated with HOMA-IR, adjusted for sex and age (râ¯=â¯-0.42; pâ¯=â¯.049). During the weight loss period participants decreased their BMI (32.1⯱â¯3.3 to 28.1⯱â¯2.8â¯kg/m2, pâ¯<â¯.01), body-fat (41.6⯱â¯6.4 to 35.0⯱â¯8.0%, pâ¯<â¯.01) and insulin resistance (HOMA-IR: 4.0⯱â¯2.0 to 1.8⯱â¯0.9, pâ¯<â¯.01). During the 22-month weight maintenance period, these parameters gradually increased again (BMI: 29.3⯱â¯3.8â¯kg/m2; body-fat: 37.8⯱â¯9.3%; HOMA-IR: 2.9⯱â¯1.4, pâ¯<â¯.01). Global grey matter volume and cortical thickness did not change significantly during the weight loss or weight maintenance period. Changes in body weight, body-fat percentage or insulin sensitivity were not associated with changes in global grey matter volume. CONCLUSION: In conclusion, we confirmed that global grey brain matter volume was inversely associated with insulin resistance at baseline, yet an intervention yielding a decrease in insulin resistance did not lead to changes in global grey brain matter volume or cortical thickness. TRIAL REGISTRATION: The trial is registered with ClinicalTrials.gov, NCT01777893.
Subject(s)
Cerebral Cortex/diagnostic imaging , Gray Matter/diagnostic imaging , Insulin Resistance/physiology , Magnetic Resonance Imaging/trends , Overweight/diagnostic imaging , Weight Loss/physiology , Adult , Female , Humans , Male , Middle Aged , Organ Size , Overweight/blood , Overweight/epidemiology , Prediabetic State/blood , Prediabetic State/diagnostic imaging , Prediabetic State/epidemiology , Risk Reduction BehaviorABSTRACT
The aim of this study was to assess the effects of a weight maintenance period comprising two diets differing in protein intake, after weight loss, on intrahepatic lipid content and implications for insulin sensitivity. A total of 25 participants [body mass index (BMI): 31.1 (3.5 kg/m2; intrahepatic lipid (IHL): 8.7 (8.3%; fasting glucose: 6.4 (0.6 mmol/l; homeostatic model assessment for insulin resistance (HOMA-IR): 3.7 (1.6; Matsuda index: 3.4 (2.9] started an 8-wk low-energy diet followed by a 2-yr weight maintenance period with either high protein or medium protein dietary guidelines. At baseline, after 6 mo, and after 2 yr, IHL, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) were determined by magnetic resonance spectroscopy/imaging. Glucose and insulin concentrations, determined during an oral glucose challenge, were used to assess the HOMA-IR and Matsuda insulin sensitivity index (ISI). Protein intake was measured with 24-h urinary nitrogen excretion. Protein intake, BMI, IHL, VAT, SAT, HOMA-IR, and ISI did not change differently between the groups during the intervention. In the whole group, BMI, IHL, VAT, SAT, HOMA-IR, and ISI were favorably changed at 6 mo and 2 yr compared with baseline ( P < 0.05). Mixed-model analysis showed that independent of BMI, protein intake (g/d) at 6 mo was inversely related to IHL (coefficient: -0.04; P < 0.05) and VAT (coefficient: -0.01; P < 0.05). Overall, IHL was positively related to HOMA-IR (coefficient: 0.10; P < 0.01) and inversely related to ISI (coefficient: -0.17; P < 0.01), independent of BMI. A 2-yr medium- to high-protein energy-restricted diet reduced IHL and VAT. Independently of changes in BMI, IHL was inversely related to insulin sensitivity.
Subject(s)
Dietary Proteins/metabolism , Insulin Resistance/physiology , Lipid Metabolism/physiology , Liver/metabolism , Weight Loss/physiology , Adult , Body Mass Index , Female , Humans , Intra-Abdominal Fat/metabolism , Male , Middle Aged , Obesity/metabolismABSTRACT
PURPOSE: The purpose of this paper is to study molecular imaging of apoptosis and necrosis, two key players in atherosclerosis instability, using a multimodal imaging approach combining single photon emission computed tomography (SPECT), positron emission tomography (PET), and computed tomography (CT). PROCEDURES: Collar-induced carotid atherosclerosis ApoE knockout mice were imaged with (99m)Tc-AnxAF568 SPECT-CT to study apoptosis and sequentially with PET-CT following (124)I-Hypericin ((124)I-Hyp) injection to visualize necrosis. RESULTS: SPECT depicted increased (99m)Tc-AnxAF568 uptake in both atherosclerotic carotid arteries, whereas our data suggest that this uptake is not merely apoptosis related. Although PET of (124)I-Hyp was hampered by the slow blood clearance in atherosclerotic mice, (124)I-Hyp was able to target necrosis in the atherosclerotic plaque. CONCLUSION: Both (99m)Tc-AnxAF568 and (124)I-Hyp uptake are increased in atherosclerotic carotid vasculature compared to control arteries. While apoptosis imaging remains challenging, necrosis imaging can be feasible after improving the biodistribution characteristics of the probe.