Advanced Molecular Imaging (MRI/MRS/1H NMR) for Metabolic Information in Young Adults with Health Risk Obesity

Abstract

Background: Obesity or being overweight is a medical condition of abnormal body fat accumulation which is associated with a higher risk of developing metabolic syndrome. The distinct body fat depots on specific parts of the anatomy have unique metabolic properties and different types of regional excessive fat distribution can be a disease hazard. The aim of this study was to identify the metabolome and molecular imaging phenotypes among a young adult population. Methods: The amount and distribution of fat and lipid metabolites profile in the abdomen, liver, and calf muscles of 46 normal weight, 17 overweight, and 13 obese participants were acquired using MRI and MR spectroscopy (MRS), respectively. The serum metabolic profile was obtained using proton NMR spectroscopy. NMR spectra were integrated into seven integration regions, which reflect relative metabolites. Results: A significant metabolic disorder symptom appeared in the overweight and obese group, and increased lipid deposition occurred in the abdomen, hepatocytes, and muscles that were statistically significant. Overall, the visceral fat depots had a marked influence on dyslipidemia biomarkers, blood triglyceride (r = 0.592, p < 0.001), and high-density lipoprotein cholesterol (r = −0.484, p < 0.001). Intrahepatocellular lipid was associated with diabetes predictors for hemoglobin (HbA1c%; r = 0.379, p < 0.001) and for fasting blood sugar (r = 0.333, p < 0.05). The lipid signals in serum triglyceride and glucose signals gave similar correspondence to biochemical lipid profiles. Conclusions: This study proves the association between alteration in metabolome in young adults, which is the key population for early prevention of obesity and metabolic syndrome. This study suggests that dyslipidemia prevalence is influenced mainly by the visceral fat depot, and liver fat depot is a key determinant for glucose metabolism and hyperglycemia. Moreover, noninvasive advanced molecular imaging completely elucidated the impact of fat distribution on the anthropometric and laboratory parameters, especially indices of the metabolic syndrome biomarkers in young adults.

Noninvasive NMR/MRS Metabolic Parameters to Evaluate Metabolic Syndrome in Rats

“…Our study evaluated the strongest relationship between visceral fat and blood cholesterol (r = 0.834, p < 0.05) among the other ectopic fat relations. This finding is consistent with our in vivo study on young adult populations in which visceral fat had the most significant and strongest relationship to blood TG and HDL-C levels when compared to abdominal and subcutaneous lipids [ 35 ]. Meek et al also found that intra-abdominal adipocytes are less responsive to insulin’s anti-lipolytic actions, and that visceral adipose tissue-derived free fatty acid (FFA) may have more significance in vivo, reaching up to 40%.…”

“…There was a similar conclusion in studies carried out on humans. This finding supports the idea that high visceral fat, especially in young obese people, could be a dyslipidemia-treated biomarker [ 35 ]. The health risks vary depending on the compartmental obesity, even in the same degree of obesity, and particularly in intra-abdominal obesity.…”

“…Furthermore, neither the subcutaneous fat relationship to plasma TG nor the association with cholesterol and FG demonstrated the less metabolic nature of subcutaneous fat. This finding totally coincided with the weak relationship of subcutaneous fat to lipid metabolites (TG and high-density lipoprotein cholesterol: HDL-C) and showed no association with FG in young adult obesity in vivo [ 35 ]. This fact supports the fact that highly mobilized TG in subcutaneous fat, which serves as a buffer during high dietary lipid intake and protects against lipotoxicity, seems to play a role in glycemic control and therefore reduces cardiovascular risk in humans [ 36 , 37 ].…”

“…In fact, they were around 9.4 and 4.1 times higher than normal-weight people, respectively. Furthermore, higher liver fat in young obese individuals may be a significant predictor of glucose metabolism and hyperglycemia [ 35 ].…”

Effects of one-year once-weekly high-intensity interval training on body adiposity and liver fat in adults with central obesity: Study protocol for a randomized controlled trial

“…A 3 × 3 × 3 cm 3 voxel will be manually placed at the right lobe of the liver (Couinaud lobe segment V-VIII), avoiding bile ducts, large vessels, focal lesions, and liver edges during the MRS scan. 23 After 5 min of the free-breathing scan, spectra will be obtained using the single-voxel point-resolved spectroscopy (PRESS) sequence. Spectral data will be exported as a raw dataset (p-file) for spectral analysis.…”