Leptin is Associated with the Tri-Ponderal Mass Index in Children: A Cross-Sectional Study.

BACKGROUND: Obesity is characterized by the disproportionate expansion of the fat mass and is most commonly diagnosed using the Body Mass Index (BMI) z-score or percentile in children. However, these measures associate poorly with the fat mass. This is important, as adiposity is a more robust predictor of cardiometabolic risk than BMI-based measures, but there are limited clinical measures of adiposity in children. A new measure, the Tri-ponderal Mass Index (TMI, kg/m3) has recently demonstrated robust prediction of adiposity in children. The aim of this study is to explore the association of leptin, a validated biomarker of the fat mass, with TMI. METHODS: One hundred and eight children and adolescents were included in this cross-sectional study. Height and weight were used to calculate TMI. Plasma leptin was measured using ELISA. Multivariable regression analysis was applied to determine the predictors of TMI. RESULTS: The age range of participants included in this study was 8.00-16.90 years (female n=48, 44%). Leptin correlated with BMI percentile (r=0.64, p-value <0.0001) and TMI (r=0.71, p-value <0.0001). The multivariable regression analysis revealed that BMI percentile (Estimated Beta-coefficient 0.002, 95% CI 0.002-0.003, p-value <0.0001) and Leptin (Estimated Beta-coefficient 0.05, 95% CI 0.02-0.07, p-value 0.013) were associated with TMI. CONCLUSION: Leptin is associated with TMI in healthy children. The TMI is a feasible clinical measure of adiposity that may be used to stratify children and adolescents for further assessments and interventions to manage and attempt to prevent cardiometabolic comorbidities.

Circulating leptin levels are associated with adiposity in survivors of childhood brain tumors.

Survivors of Childhood Brain Tumors (SCBT) are at a higher risk of developing cardiovascular disease and type 2 diabetes compared to the general population. Adiposity is an important risk factor for the development of these outcomes, and identifying biomarkers of adiposity may help the stratification of survivors based on their cardiovascular risk or allow for early screening and interventions to improve cardiometabolic outcomes. Leptin is an adipokine that positively correlates with the adipose mass in the general population and is a predictor of adverse cardiometabolic outcomes, yet its association with adiposity in SCBT has not been studied. The aim of this study was to determine if leptin levels are associated with the adipose mass in SCBT, and to define its predictors. This cross-sectional study included 74 SCBT (n = 32 females) with 126 non-cancer controls (n = 59 females). Total adiposity was measured using Bioelectrical Impendence Analysis (BIA) and central adiposity was measured using waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR). We used multivariable linear regression analysis to determine if leptin predicts adiposity in SCBT and adjusted for age, sex, puberty, and cancer status. Leptin correlated strongly with total (p < 0.001) and central (WHR p = 0.001; WHtR p < 0.001) adiposity in SCBT and non-cancer controls. In conclusion, leptin is a potential biomarker for adiposity in SCBT, and further investigation is needed to clarify if leptin is a predictor of future cardiometabolic risk in SCBT.

Structural snapshot of the cholesterol-transport ATP-binding cassette proteins 1.

The ATP-binding cassette (ABC) proteins play critical roles in maintaining lipid and sterol homeostasis in higher eukaryotes. In humans, several subfamily-A and -G members function as cholesterol transporters across the cellular membranes. Deficiencies of these ABC proteins can cause dyslipidemia that is associated with health conditions such as atherosclerosis, diabetes, fatty liver disease, and neurodegeneration. The physiological roles of ABC cholesterol transporters have been implicated in mediating cholesterol efflux for reverse cholesterol transport and in maintaining membrane integrity for cell survival. The precise role of these ABC transporters in cells remains elusive, and little is known about the sterol-transport mechanism. The membrane constituents of ABC transporters have been postulated to play a key role in determining the transport substrates and the translocation mechanisms via the transmembrane domains. Recent breakthroughs in determining high-resolution structures of the human sterol transporter ABCG5/G8 and its functional homologs have shed light on new structural features of ABC transporters, providing a more relevant framework for mechanistic analysis of cholesterol-transport ABC proteins. This minireview outlines what is known about ABCG cholesterol transporters, addresses key structural features in the putative sterol translocation pathway on the transmembrane domains, and concludes by proposing a mechanistic model of ABC cholesterol transporters.