Untargeted metabolomics identifies a plasma sphingolipid-related signature associated with lifestyle intervention in prepubertal children with obesity.

OBJECTIVE: Childhood obesity is a strong risk factor for adult obesity and metabolic diseases, including type 2 diabetes and cardiovascular disease. Early lifestyle intervention in children with obesity reduces future disease risk. The objective of this study is to identify metabolic signatures associated with lifestyle intervention in prepubertal children with obesity. METHODS: Thirty-five prepubertal children (7-10 years) with obesity (body mass index (BMI)>2 standard deviations) were enrolled in the study and participated in a 6-month-long lifestyle intervention program. Physiological and biochemical data and blood samples were collected both at baseline and after the intervention. A liquid chromatography-mass spectrometry (LC-MS)-based metabolomics approach was applied to obtain a comprehensive profiling of plasma samples, identifying 2581 distinct metabolite. Principal component analysis (PCA) was performed to consolidate all features into 8 principal components. Associations between metabolites and physiological and biochemical variables were investigated. RESULTS: The intervention program significantly decreased mean (95% CI) BMI standard deviation score from 3.56 (3.29-3.84) to 3.11 (2.88-3.34) (P<0.001). PCA identified one component (PC1) significantly altered by the intervention (Bonferroni adjusted P=0.008). A sphingolipid metabolism-related signature was identified as the major contributor to PC1. Sphingolipid metabolites were decreased by the intervention, and included multiple sphingomyelin, ceramide, glycosylsphingosine and sulfatide species. Changes in several sphingolipid metabolites were associated with intervention-induced improvements in HbA1c levels. CONCLUSIONS: Decreased circulating sphingolipid-related metabolites were associated with lifestyle intervention in prepubertal children with obesity, and correlated to improvements in HbA1c.

Opposite changes in meteorin-like and oncostatin m levels are associated with metabolic improvements after bariatric surgery.

Bariatric surgery is currently the most effective therapy for type 2 diabetes. However, the mechanisms underlying its beneficial effects remain elusive. Here we studied the effects of bariatric surgery on circulating meteorin-like (Metrnl) and oncostatin m (OSM) levels, two hormones intimately linked to energy homeostasis. Metrnl and OSM levels were assessed at baseline, 6 and 12 months after laparoscopic sleeve gastrectomy (LSG) in 25 patients with obesity, as well as in 33 normal-weight controls. At baseline, patients with obesity showed lower Metrnl and higher OSM levels compared to controls. LSG increased Metrnl and decreased OSM levels, in correlation to improvements in glucose and lipid homeostasis. Our data indicate that LSG conversely modulated Metrnl and OSM levels, and suggest that a dual approach modulating these two molecules might provide a novel strategy for obesity and type 2 diabetes treatment.

Novel Assessment of Ischemia in Patients With Anomalous Right Coronary Artery.

Anomalous right coronary arteries are usually benign; however, sudden death owing to myocardial ischemia, especially during exertion, have been reported in patients with intramural or interarterial course, which is likely due to dynamic obstruction. We propose a novel method of physiological evaluation with instantaneous wave-free ratio with dobutamine infusion to simulate controlled dynamic obstruction in anomalous right coronary arteries. (Level of Difficulty: Intermediate.).

Autophagic control of cardiac steatosis through FGF21 in obesity-associated cardiomyopathy.

OBJECTIVE: High-fat diet-induced obesity leads to the development of hypertrophy and heart failure through poorly understood molecular mechanisms. We have recently shown that fibroblast growth factor-21 (FGF21) is produced by the heart and exerts protective effects that prevent cardiac hypertrophy development and oxidative stress. The aim of this study was to determine the effects of FGF21 on the cardiomyopathy associated with obesity development. RESULTS: Fgf21-/- mice showed an enhanced increase in the heart weight/tibia length (HW/TL) ratio in response to the high-fat diet. In keeping with this, echocardiographic measurements confirmed enhanced cardiac hypertrophy in Fgf21-/- mice. At the cellular level, the area of cardiomyocytes was increased in Fgf21-/- mice fed a high-fat diet. Furthermore, a high-fat diet induced fatty acid oxidation in the hearts of Fgf21-/- mice accompanied by an increase in cardiac oxidative stress. Oil-red O staining revealed the presence of higher amounts of lipid droplets in the hearts of Fgf21-/- mice fed a high-fat diet relative to wt mice fed this same diet. Finally, Fgf21-/- mice fed a high-fat diet showed impaired cardiac autophagy and signs of inactive cardiac lipophagy, suggesting that FGF21 promotes autophagy in cardiomyocytes. CONCLUSIONS: Our data indicate that a lack of FGF21 enhances the susceptibility of mice to the development of obesity-related cardiomyopathy. Furthermore, we demonstrate that this cardiac dysfunction is associated with deleterious lipid accumulation in the heart. An impaired ability of FGF21 to promote autophagy/lipophagy may contribute to lipid accumulation and cardiac derangements.

Overexpression of protein targeting to glycogen in cultured human muscle cells stimulates glycogen synthesis independent of glycogen and glucose 6-phosphate levels.

There is growing evidence that glycogen targeting subunits of protein phosphatase-1 play a critical role in regulation of glycogen metabolism. In the current study, we have investigated the effects of adenovirus-mediated overexpression of a specific glycogen targeting subunit known as protein targeting to glycogen (PTG) in cultured human muscle cells. PTG was overexpressed both in muscle cells cultured at high glucose (glycogen replete) or in cells incubated for 18 h in the absence of glucose and then incubated in high glucose (glycogen re-synthesizing). In both glycogen replete and glycogen resynthesizing cells, PTG overexpression caused glycogen to be synthesized at a linear rate 1-5 days after viral treatment, while in cells treated with a virus lacking a cDNA insert (control virus), glycogen content reached a plateau at day 1 with no further increase. In the glycogen replete PTG overexpressing cells, glycogen content was 20 times that in controls at day 5. Furthermore, in cells undergoing glycogen resynthesis, PTG overexpression caused a doubling of the initial rate of glycogen synthesis over the first 24 h relative to cells treated with control virus. In both sets of experiments, the effects of PTG on glycogen synthesis were correlated with a 2-3-fold increase in glycogen synthase activity state, with no changes in glycogen phosphorylase activity. The alterations in glycogen synthase activity were not accompanied by changes in the intracellular concentration of glucose 6-phosphate. We conclude that PTG overexpression activates glycogen synthesis in a glucose 6-phosphate-independent manner in human muscle cells while overriding glycogen-mediated inhibition. Our findings suggest that modulation of PTG expression in muscle may be a mechanism for enhancing muscle glucose disposal and improving glucose tolerance in diabetes.