Muscle Ultrasound Changes and Physical Function of Critically Ill Children: A Comparison of Rectus Femoris Cross-Sectional Area and Quadriceps Thickness Measurements.

Quadriceps thickness (QT) and rectus femoris cross-sectional area (RFCSA) are both used to evaluate muscle changes in critically ill children. However, their correlation and association with physical function has not been compared. OBJECTIVES: To compare QT with RFCSA changes, and their association with physical function in critically ill children. DESIGN SETTING AND PARTICIPANTS: Secondary analysis of a prospective cohort study of children 0-18 years old admitted to a tertiary mixed PICU between January 2015 and October 2018 with PICU stay greater than 48 hours and greater than or equal to one organ dysfunction. MAIN OUTCOMES AND MEASURES: Ultrasound QT and RFCSA were measured at PICU admission, PICU discharge, hospital discharge, and 6 months post-discharge. QT and RFCSA changes from baseline were compared with each other and with change in motor function, physical ability, and physical health-related quality of life (HRQOL). RESULTS: Two hundred thirty-seven images from 66 subjects were analyzed. RFCSA change was not significantly different from QT change at PICU (-8.07% [interquartile range (IQR), -17.11% to 4.80%] vs -4.55% [IQR, -14.32% to 4.35%]; p = 0.927) or hospital discharge (-5.62% [IQR, -15.00% to 9.42%] vs -8.81% [IQR, -18.67% to 2.39%]; p = 0.238) but was significantly greater than QT change at 6 months (32.7% [IQR, 5.74-109.76%] vs 9.66% [IQR, -8.17% to 25.70%]; p < 0.001). Motor function change at PICU discharge was significantly associated with RFCSA change (adjusted ß coefficient, 0.02 [95% CI, 0.01-0.03]; p = 0.013) but not QT change (adjusted ß coefficient, -0.01 [95% CI, -0.02 to 0.01]; p = 0.415). Similar results were observed for physical HRQOL changes at hospital discharge (adjusted ß coefficient for RFCSA change, 0.51 [95% CI, 0.10-0.92]; p = 0.017 and adjusted ß coefficient for QT change, -0.21 [-0.76 to 0.35]; p = 0.458). Physical ability was not significantly associated with RFCSA or QT changes at 6 months post-discharge. CONCLUSIONS AND RELEVANCE: Ultrasound derived RFCSA is associated with PICU motor function and hospital discharge physical HRQOL changes, unlike QT, and may be more useful for in-hospital muscle monitoring in critically ill children.

Brown fat detection by infrared thermography-An invaluable research methodology with noteworthy uncertainties confirmed by a mathematical proof.

Brown adipose tissue (BAT) represents a pivotal scientific renaissance worthy as a strategy for obesity and diabetes since its re-discovery in adults over a decade ago. Equally compelling is the adoption of infrared thermography (IRT) in recent times as a precise and viable alternative methodology over the 'gold standard' PET-CT scan, given constraints of the latter's high ionizing radiation doses and costs. Unravelling BAT metabolic physiology in live humans has been challenging until recent rigorous validation of IRT against PET. Nevertheless, IRT remains a nascent technique with pitfalls unbeknownst to many researchers. Factors impacting its accuracy merit an in-depth scientific scrutiny. This article discusses the strengths and pitfalls of IRT as an emergent BAT detection technique and provides a mathematical proof of its limitations that BAT researchers should be cognizant of. Understanding these limitations of IRT can prompt extra efforts to control these uncertainties with greater rigour. In conclusion, this warrants further investigations of improving IRT quality via advanced auto-segmentation, powerful image processing of thermograms and protocol standardization along the lines of BARCIST 1.0 to minimize errors and enhance the confidence of the global BAT research community in IRT as a robust and reliable BAT research tool.

A narrative review of skeletal muscle atrophy in critically ill children: pathogenesis and chronic sequelae.

Muscle wasting is now recognized as a growing, debilitating problem in critically ill adults, resulting in long-term deficits in function and an impaired quality of life. Ultrasonography has demonstrated decreases in skeletal muscle size during pediatric critical illness, although variations exist. However, muscle protein turnover patterns during pediatric critical illness are unclear. Understanding muscle protein turnover during critical illness is important in guiding interventions to reduce muscle wasting. The aim of this review was to explore the possible protein synthesis and breakdown patterns in pediatric critical illness. Muscle protein turnover studies in critically ill children are lacking, with the exception of those with burn injuries. Children with burn injuries demonstrate an elevation in both muscle protein breakdown (MPB) and synthesis during critical illness. Extrapolations from animal models and whole-body protein turnover studies in children suggest that children may be more dependent on anabolic factors (e.g., nutrition and growth factors), and may experience greater muscle degradation in response to insults than adults. Yet, children, particularly the younger ones, are more responsive to anabolic agents, suggesting modifiable muscle wasting during critical illness. There is a lack of evidence for muscle wasting in critically ill children and its correlation with outcomes, possibly due to current available methods to study muscle protein turnover in children-most of which are invasive or tedious. In summary, children may experience muscle wasting during critical illness, which may be more reversible by the appropriate anabolic agents than adults. Age appears an important determinant of skeletal muscle turnover. Less invasive methods to study muscle protein turnover and associations with long-term outcome would strengthen the evidence for muscle wasting in critically ill children.

A Cross-Sectional Study of the Clinical Metrics of Functional Status Tools in Pediatric Critical Illness.

OBJECTIVES: To determine the clinical metrics of functional assessments in pediatric critical illness survivors. DESIGN: Cross-sectional observational study. SETTING: PICU follow-up clinic. PATIENTS: Forty-four PICU survivors 6-12 months post PICU stay, and 52 healthy controls 0-18 years old. INTERVENTIONS: Nil. MEASUREMENTS AND MAIN RESULTS: Function was assessed using the Pediatric Quality of Life Inventory 4.0 generic scales and infant scales, the Pediatric Evaluation of Disability Inventory-Computer Adaptive Test, and the Functional Status Scale. Muscle strength was assessed by hand grip strength in children greater than or equal to 6 years. Clinical metrics assessed included floor and ceiling effects, known-group, and convergent validity. Floor and ceiling effects were present if the participants achieving the worst or best scores exceeded 15%, respectively. Known-group validity was assessed by comparing scores between those with and without complex chronic conditions and abnormal versus good baseline function. Convergent validity was assessed using partial correlation between two tools. Functional Status Scale and Pediatric Quality of Life Inventory physical domain scores showed significant ceiling effects in PICU survivors (69.2% and 15.4%, respectively, achieved the highest possible score). Functional scores were not significantly different between children with or without complex chronic conditions or children with good versus abnormal baseline function. In healthy children, Pediatric Quality of Life Inventory physical correlated moderately with hand grip strength (partial r = 0.66; p < 0.001), whereas Pediatric Quality of Life Inventory psychosocial correlated moderately with Pediatric Evaluation of Disability Inventory-Computer Adaptive Test social/cognitive score (partial r = 0.53; p < 0.001). In PICU survivors, only Pediatric Quality of Life Inventory physical and Pediatric Evaluation of Disability Inventory-Computer Adaptive Test mobility scores were correlated (partial r = 0.55; p < 0.001). CONCLUSIONS: PICU functional assessment tools have varying clinical metrics. Considering ceiling effects, Pediatric Evaluation of Disability Inventory-Computer Adaptive Test may be more suitable in survivors than Functional Status Scale. Differences in scores between children with or without complex chronic conditions, and with or without baseline functional impairment, were not observed. Functional assessments likely require a combination of tools to measure the spectrum of pediatric critical illness and recovery.

Skeletal Muscle Changes, Function, and Health-Related Quality of Life in Survivors of Pediatric Critical Illness.

OBJECTIVES: To describe functional and skeletal muscle changes observed during pediatric critical illness and recovery and their association with health-related quality of life. DESIGN: Prospective cohort study. SETTING: Single multidisciplinary PICU. PATIENTS: Children with greater than or equal to 1 organ dysfunction, expected PICU stay greater than or equal to 48 hours, expected survival to discharge, and without progressive neuromuscular disease or malignancies were followed from admission to approximately 6.7 months postdischarge. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Functional status was measured using the Functional Status Scale score and Pediatric Evaluation of Disability Inventory-Computer Adaptive Test. Patient and parental health-related quality of life were measured using the Pediatric Quality of Life Inventory and Short Form-36 questionnaires, respectively. Quadriceps muscle size, echogenicity, and fat thickness were measured using ultrasonography during PICU stay, at hospital discharge, and follow-up. Factors affecting change in muscle were explored. Associations between functional, muscle, and health-related quality of life changes were compared using regression analysis. Seventy-three survivors were recruited, of which 44 completed follow-ups. Functional impairment persisted in four of 44 (9.1%) at 6.7 months (interquartile range, 6-7.7 mo) after discharge. Muscle size decreased during PICU stay and was associated with inadequate energy intake (adjusted ß, 0.15; 95% CI, 0.02-0.28; p = 0.030). No change in echogenicity or fat thickness was observed. Muscle growth postdischarge correlated with mobility function scores (adjusted ß, 0.05; 95% CI, 0.01-0.09; p = 0.046). Improvements in mobility scores were associated with improved physical health-related quality of life at follow-up (adjusted ß, 1.02; 95% CI, 0.23-1.81; p = 0.013). Child physical health-related quality of life at hospital discharge was associated with parental physical health-related quality of life (adjusted ß, 0.09; 95% CI, 0.01-0.17; p = 0.027). CONCLUSIONS: Muscle decreased in critically ill children, which was associated with energy inadequacy and impaired muscle growth postdischarge. Muscle changes correlated with change in mobility, which was associated with child health-related quality of life. Mobility, child health-related quality of life, and parental health-related quality of life appeared to be interlinked.

Dissociation Between Insulin Resistance and Abnormalities in Lipoprotein Particle Concentrations and Sizes in Normal-Weight Chinese Adults.

Insulin resistance in obesity coincides with abnormalities in lipid profile and lipoprotein subclass distribution and size even before abnormalities in glucose homeostasis manifest. We aimed to assess this relationship in the absence of obesity. Insulin sensitivity (3-h intravenous glucose tolerance test and minimal modeling) and lipoprotein particle concentrations and sizes (proton nuclear magnetic resonance spectroscopy) were evaluated in 15 insulin-resistant and 15 insulin-sensitive lean Asians of Chinese descent with normal glucose tolerance, matched on age, sex, and body mass index. Despite a ~50% lower insulin sensitivity index (Si) in insulin-resistant than in insulin-sensitive subjects, which was accompanied by significantly greater acute insulin response to glucose (AIRg) and fasting insulin concentration but not different fasting glucose concentration, there were no significant differences between groups in the blood lipid profile (p ≥ 0.44) or the lipoprotein subclass concentrations (p ≥ 0.30) and particle sizes (p ≥ 0.43). We conclude that, contrary to observations in subjects with obesity, insulin resistance is not accompanied by unfavorable changes in the plasma lipid profile and lipoprotein particle concentrations and sizes in lean Asians with normal glucose tolerance. Therefore, insulin resistance at the level of glucose metabolism is mechanistically or temporally dissociated from lipid and lipoprotein metabolism. Trial Registration: clinicaltrials.gov, NCT03264001.

Branched-Chain Amino Acid Supplementation Does Not Preserve Lean Mass or Affect Metabolic Profile in Adults with Overweight or Obesity in a Randomized Controlled Weight Loss Intervention.

BACKGROUND: Branched-chain amino acid (BCAA) supplementation has been shown to increase muscle mass or prevent muscle loss during weight loss. OBJECTIVE: We aimed to investigate the effects of a BCAA-supplemented hypocaloric diet on lean mass preservation and insulin sensitivity. METHODS: A total of 132 Chinese adults (63 men and 69 women aged 21-45 y, BMI 25-36 kg/m2) were block randomly assigned by gender and BMI into 3 hypocaloric diet (deficit of 500 kcal/d) groups: standard-protein (14%) with placebo (control, CT) or BCAA supplements at 0.1 g · kg-1 body weight · d-1 (BCAA) or high-protein (27%) with placebo (HP). The subjects underwent 16 wk of dietary intervention with provision of meals and supplements, followed by 8 wk of weight maintenance with provision of supplements only. One-way ANOVA analysis was conducted to analyze the primary (lean mass and insulin sensitivity) and secondary outcomes (anthropometric and metabolic parameters) among the 3 groups. Paired t-test was used to analyze the change in each group. RESULTS: The 3 groups demonstrated similar significant reductions in body weight (7.97%), fat mass (13.8%), and waist circumference (7.27%) after 16 wk of energy deficit. Lean mass loss in BCAA (4.39%) tended to be lower than in CT (5.39%) and higher compared with HP (3.67%) (P = 0.06). Calf muscle volume increased 3.4% in BCAA and intramyocellular lipids (IMCLs) decreased in BCAA (17%) and HP (18%) (P < 0.05) over 16 wk. During the 8 wk weight maintenance period, lean mass gain in BCAA (1.03%) tended to be lower compared with CT (1.58%) and higher than in HP (-0.002%) (P = 0.04). Lean mass gain differed significantly between CT and HP (P = 0.03). Insulin sensitivity and metabolic profiles did not differ among the groups throughout the study period. CONCLUSIONS: BCAA supplementation does not preserve lean mass or affect insulin sensitivity in overweight and obese adults during weight loss. A higher protein diet may be more advantageous for lean mass preservation.

Therapeutic plasma exchange for control of thyroid storm.

Therapeutic plasma exchange (TPE) for thyroid storm has recently been upgraded to a category II indication after decades though its recommendation level still remains at Grade 2C according to the American Society for Apheresis (ASFA). In the absence of prospective randomized controlled trials due to the rarity of thyroid storm, retrospective data from case series continue to elevate the clinical evidence supporting TPE as a life-saving modality for complicated thyroid storm patients. We report three cases of life-threatening thyroid storm from Graves' disease rescued by TPE via rapid reduction in circulating thyroid hormones. Each patient underwent TPE when it was judged that other thyroid storm treatment options were futile or unsafe. The first patient received 4 cycles of TPE while the second patient received 9 cycles of TPE, and the third patient received 2 cycles of TPE with satisfactory clinical improvement. Plasma FT4 and TSH receptor antibody levels of the first case declined by 41.3% and >50% respectively right after the first round of TPE; plasma FT4 of the second patient dropped by up to 31.6% during the course of TPE; plasma FT4 and TSH receptor antibody of the third patient declined by 66% and 56.2% respectively after the first cycle of TPE. This demonstrates the safety, efficacy, and feasibility of TPE in thyroid storm especially when other therapeutic interventions are contraindicated. TPE operates via the elimination of serum proteins-bound thyroid hormones, thyroid autoantibodies, cytokines, and catecholamines in addition to increasing unsaturated binding sites for thyroid hormones.

Impact of Vitamin E supplementation on vascular function in haptoglobin genotype stratified diabetes patients (EVAS Trial): a randomised controlled trial.

AIMS: Vitamin E (Vit-E) may preferentially improve cardiovascular risk in haptoglobin 2-2 (Hp2-2) genotype diabetes individuals. We studied the impact of Vit-E supplementation on vascular function in diabetes individuals stratified by haptoglobin genotype in Singapore. METHODS: In this 24-week, double blind, placebo-controlled RCT, we recruited 187 subjects (101 Hp2-2, 86 non-Hp2-2). INTERVENTION: alpha-tocopherol-400 IU. PRIMARY OUTCOME: Change in EndoPAT-derived reactive-hyperaemia index (RHI) and augmentation index (AIx); Secondary Outcomes: Pulse-Wave velocity (Sphygmocor-PWV), carotid intima media thickness (CIMT), inflammation (hsCRP), derivatives of reactive-oxygen metabolites (dROMs), biological antioxidant-potential (BAPs), HbA1c, LDL-C, HDL-C and oxidised LDL-C (ox-LDL). RESULTS: Overall, with Vit-E supplementation no significant change in RHI, PWV, CIMT, hsCRP, dROMS, BAPs, HDL-C and HbA1c was observed (p > 0.05); an increase in LDL-C with concomitant decrease in ox-LDL, and incidentally increase in eGFR was observed (p < 0.05). No interaction effect with haptoglobin genotype was seen for all outcomes (p > 0.05). Subgroup analysis: In the non-Hp-2-2 group, Vit-E supplementation led to a higher EndoPAT-derived AIx, accompanied by higher LDL and ox-LDL concentrations (p < 0.05); Hp2-2 group: Vit-E supplementation led to higher eGFR when compared to the non-Hp2-2 group (exploratory) (p < 0.05). We observed an interaction effect for baseline haptoglobin concentration (threshold > 119 mg/dl) with intervention in terms of increased EndoPAT-derived AIx in the Hp > 119 mg/dl group whereas no change in the group with Hp ≤ 119 mg/dl. CONCLUSION: Vit-E supplementation did not show any preferential benefit or deleterious effect on vascular function in Hp2-2 diabetes subjects in Singapore. A possible deleterious effect of an increase in arterial stiffness in individuals with Hp > 119 mg/dl was observed. Future studies should consider personalisation based on baseline Hp concentrations in patients with T2DM rather than just Hp2-2 genotype to evaluate impact on the detailed lipid pathways, cardiac and renal physiology. The impact of ethnic differences needs to be explored in greater details.

Determinants of intramyocellular lipid accumulation in early childhood.

BACKGROUND/OBJECTIVES: Accumulation of lipid droplets inside skeletal muscle fibers (intramyocellular lipids or IMCL) with increasing obesity has been linked to skeletal muscle insulin resistance and risk of type 2 diabetes in both adults and prepubertal children. We aimed to evaluate the associations of race, genotype, prenatal factors, and postnatal factors with IMCL in early childhood. SUBJECTS/METHODS: This study was a secondary analysis performed on the GUSTO birth cohort. Soleus muscle IMCL of 392 children at 4.5 years of age was measured by magnetic resonance spectroscopy, of which usable imaging data were obtained from 277 children (137 Chinese, 87 Malays, and 53 Indians). Metabolic assessments (fasting glucose, insulin, and HOMA-IR) were performed at age 6. RESULTS: The mean IMCL level at 4.5 years was 0.481 ± 0.279% of water resonance (mean ± sd). Corroborating with results from adults, Indian children had the highest IMCL levels compared with Malay and Chinese children. Among the prenatal factors, the rate of gestational weight gain (GWG rate) was associated with offspring IMCL (B = 0.396 (0.069, 0.724); p = 0.018). Both race and GWG rate continued to be associated with offspring IMCL even after accounting for current offspring BMI. Postnatally, IMCL was associated with shorter breastfeeding duration (B = 0.065 (0.001, 0.128); p = 0.045) and conditional relative weight gain between ages 2 and 3 (B = 0.052 (0.012, 0.093); p = 0.012). The associations with postnatal factors were attenuated after adjusting for current offspring BMI. IMCL was positively associated with offspring BMI (B = 0.028 (0.012, 0.044); p = 0.001). IMCL levels were not associated with fasting glucose, fasting insulin, and HOMA-IR at age 6. CONCLUSION: This study provides evidence that IMCL accumulation occurs in early childhood and that developmental factors and race are associated with it. We also show that early childhood IMCL accumulation is well tolerated, suggesting that the adverse associations between IMCL and insulin resistance may emerge at older ages.

Body Composition and Acquired Functional Impairment in Survivors of Pediatric Critical Illness.

OBJECTIVES: To identify whether body mass and composition is associated with acquired functional impairment in PICU survivors. DESIGN: Retrospective dual-cohort study. SETTING: Single multidisciplinary PICU. PATIENTS: Two distinct PICU survivor cohorts: 432 unselected admissions from April 2015 to March 2016, and separately 92 patients with abdominal CT imaging at admission from January 2010 to December 2016. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Admission body mass index and Functional Status Scale scores at admission, PICU discharge, and hospital discharge were obtained for all patients. Acquired functional impairment was defined as increase greater than or equal to 3 in Functional Status Scale from baseline. Patients were classified as having: "temporary acquired impairment" (acquired impairment at PICU discharge recovering by hospital discharge), "persistent acquired impairment" (acquired impairment at PICU discharge persisting to hospital discharge), and "no acquired impairment." CT scans were analyzed for skeletal muscle and fat area using National Institute of Health ImageJ software (Bethesda, MD). Multinomial logistic regression analyses were conducted to identify associations between body mass index, muscle and fat indices, and acquired functional impairment. High baseline body mass index was consistently predictive of persistent acquired impairment in both cohorts. In the second cohort, when body mass index was replaced with radiologic anthropometric measurements, greater skeletal muscle, and visceral adipose tissue indices were independently associated with persistent acquired impairment at hospital discharge (adjusted odds ratio, 1.29; 95% CI, 1.03-1.61; p = 0.024 and adjusted odds ratio, 1.13; 95% CI, 1.01-1.28; p = 0.042, respectively). However, this relationship was no longer significant in children with PICU stay greater than 2 days. CONCLUSIONS: In PICU survivors, baseline body mass and composition may play a role in the persistence of acquired functional impairment at hospital discharge. Characterization and quantification of skeletal muscle and fat deserves further study in larger cohorts of PICU children.

Dose-Dependent Effects of Exercise and Diet on Insulin Sensitivity and Secretion.

PURPOSE: A single bout of aerobic exercise increases insulin sensitivity the next day. The effects of exercise on insulin secretion, the role of exercise-induced energy deficit, and possible dose-response relationships are not well understood. This study aimed to evaluate insulin sensitivity and insulin secretion after progressively greater negative energy balance induced by exercise or diet. METHODS: Acute energy deficits (20% or 40% of weight maintenance needs) were induced by a single day of aerobic exercise (cycling at moderate intensity, n = 13) or dietary restriction (n = 19) in healthy men and women (age, 26 ± 2 yr; body mass index, 21.8 ± 0.5 kg·m). Intravenous glucose tolerance tests in conjunction with minimal modeling were performed the next morning, and blood samples were collected for 3 h to measure glucose and insulin concentrations. RESULTS: Insulin sensitivity increased linearly after exercise-induced energy deficits (P = 0.007) but did not change after equivalent diet-induced energy deficits (P = 0.673). Acute insulin response decreased after both exercise (P < 0.001) and dietary restriction (P = 0.005). The disposition index and glucose effectiveness were not affected by exercise (P = 0.138 and 0.808, respectively), but both decreased after 40% dietary restriction (P = 0.048 and 0.002, respectively). CONCLUSIONS: These results indicate that insulin sensitivity and insulin secretion are related to exercise energy expenditure, albeit in a different fashion (insulin sensitivity increases linearly, whereas insulin secretion drops to a nadir with a low exercise dose and does not decrease further). These changes cannot be replicated by equivalent energy deficits induced by dietary restriction, suggesting that exercise and diet have different effects on the mechanisms regulating glucose homeostasis. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03264001.

Ectopic fat and aerobic fitness are key determinants of glucose homeostasis in nonobese Asians.

BACKGROUND: The importance of ectopic fat deposition and physical fitness in the pathogenesis of insulin resistance and beta cell dysfunction in subjects from the nonobese Asians is not known. MATERIALS AND METHODS: We conducted a cross-sectional study and measured insulin sensitivity (M value; 4-hour hyperinsulinaemic-euglycaemic clamp), insulin secretion rate (3-hour mixed meal tolerance test with oral minimal modelling), percent body fat, visceral adipose tissue, intramyocellular and intrahepatic lipid contents (magnetic resonance imaging and spectroscopy), cardiorespiratory fitness (VO2 max; graded exercise test) and habitual physical activity (short International Physical Activity Questionnaire) in 60 healthy nonobese Asian subjects (BMI = 21.9 ± 1.7 kg/m2 , age = 41.8 ± 13.4 years). RESULTS: M was inversely associated with percent body fat (r = -0.460, P < 0.001), visceral fat (r = -0.623, P < 0.001) and liver fat (r = -0.601, P < 0.001), whereas insulin secretion correlated positively with these adiposity indices (percent body fat: r = 0.303, P = 0.018; visceral fat: r = 0.409, P = 0.010; hepatic fat: r = 0.393, P = 0.002). VO2 max correlated negatively with insulin secretion rate (r = -0.420, P < 0.001) and positively with M (r = 0.658, P < 0.001). The amount of vigorous physical activity was positively associated with VO2 max (r = 0.682, P < 0.001). Multiple stepwise linear regression analyses indicated that VO2 max, age, and IHTG or VAT were independent determinants of insulin sensitivity and secretion (adjusted R2  = 69% and 33%, respectively, P < 0.001). CONCLUSIONS: Increased ectopic fat deposition is associated with reduced insulin sensitivity and increased insulin secretion in healthy nonobese Asians. Poor cardiorespiratory fitness, likely due to inadequate participation in vigorous exercise, is strongly related to suboptimal metabolic function. Interventions to encourage engagement in physical activity may thus be important for improving metabolic health in nonobese Asians.

Lipoprotein Subclass Profile after Progressive Energy Deficits Induced by Calorie Restriction or Exercise.

Weight loss, induced by chronic energy deficit, improves the blood lipid profile. However, the effects of an acute negative energy balance and the comparative efficacy of diet and exercise are not well-established. We determined the effects of progressive, acute energy deficits (20% or 40% of daily energy requirements) induced by a single day of calorie restriction (n = 19) or aerobic exercise (n = 13) in healthy subjects (age: 26 ± 9 years; body mass index (BMI): 21.8 ± 2.9 kg/m²). Fasting plasma concentrations of very low-, intermediate-, low-, and high-density lipoprotein (VLDL, LDL, IDL, and HDL, respectively) particles and their subclasses were determined using nuclear magnetic resonance. Total plasma triglyceride and VLDL-triglyceride concentrations decreased after calorie restriction and exercise (all p ≤ 0.025); the pattern of change was linear with an increasing energy deficit (all p < 0.03), with no evidence of plateauing. The number of circulating large and medium VLDL particles decreased after diet and exercise (all p < 0.015), with no change in small VLDL particles. The concentrations of IDL, LDL, and HDL particles, their relative distributions, and the particle sizes were not altered. Our data indicate that an acute negative energy balance induced by calorie restriction and aerobic exercise reduces triglyceride concentrations in a dose-dependent manner, by decreasing circulating large and medium VLDL particles.

Visceral adipose tissue tracks more closely with metabolic dysfunction than intrahepatic triglyceride in lean Asians without diabetes.

Increased visceral adipose tissue (VAT) and intrahepatic triglyceride (IHTG) are important risk factors for the development of type 2 diabetes in subjects with obesity. The relative contribution of these ectopic fat depots to cardiometabolic risk differs between populations, depends on the degree of obesity and the level of cardiorespiratory fitness, and is difficult to dissect because VAT and IHTG typically covary. The aim of this study was to evaluate the effect of an isolated increase in VAT or IHTG on insulin sensitivity and insulin secretion in apparently healthy normal-weight Asian subjects. Total body fat (dual X-ray absorptiometry), VAT and IHTG (magnetic resonance), insulin sensitivity (4-h hyperinsulinemic-euglycemic clamp), beta cell responsivity and insulin secretion rate (3-h mixed meal with mathematical modeling), and cardiorespiratory fitness (maximal oxygen consumption [V̇o2max]) were evaluated in groups of lean subjects with low or high VAT (687 ± 94 vs. 1,279 ± 197 ml, matched for IHTG; n = 13 each) and low or high IHTG (1.7 ± 0.3 vs. 6.7 ± 2.0%, matched for VAT; n = 15 each). All groups were matched for age, sex, total body fat, and V̇o2max. High-VAT subjects had ~25% lower insulin sensitivity, ~20%-40% greater beta cell responsivity and insulin secretion rate, ~35% greater fasting triglyceride concentration, and ~40% lower adiponectin concentration than low-VAT subjects (all P < 0.05). No differences were observed between low-IHTG and high-IHTG subjects. Accumulation of excess fat in the intra-abdominal area is more strongly associated with metabolic dysfunction than accumulation of liver fat in lean Asians without diabetes. NEW & NOTEWORTHY It is not known whether metabolic abnormalities in Asians without obesity track more closely with visceral or liver fat. We found an isolated increase in visceral fat was associated with reduced insulin sensitivity, greater insulin secretion, greater triglyceride, and lower adiponectin concentrations; no differences were observed with an isolated increase in liver fat. These results suggest that visceral fat is a better correlate of metabolic dysfunction than liver fat in Asians without obesity.

Skeletal Muscle Ultrasonography in Nutrition and Functional Outcome Assessment of Critically Ill Children: Experience and Insights From Pediatric Disease and Adult Critical Care Studies [Formula: see text].

Evidence suggests that critically ill children develop muscle wasting, which could affect outcomes. Muscle ultrasound has been used to track muscle wasting and association with outcomes in critically ill adults but not children. This review aims to summarize methodological considerations of muscle ultrasound, structural findings, and possibilities for its application in the assessment of nutrition and functional outcomes in critically ill children. Medline, Embase, and CINAHL databases were searched up until April 2016. Articles describing skeletal muscle ultrasound in children and critically ill adults were analyzed qualitatively for details on techniques and findings. Thickness and cross-sectional area of various upper and lower body muscles have been studied to quantify muscle mass and detect muscle changes. The quadriceps femoris muscle is one of the most commonly measured muscles due to its relation to mobility and is sensitive to changes over time. However, the margin of error for quadriceps thickness is too wide to reliably detect muscle changes in critically ill children. Muscle size and its correlation with strength and function also have not yet been studied in critically ill children. Echogenicity, used to detect compromised muscle structure in neuromuscular disease, may be another property worth studying in critically ill children. Muscle ultrasound may be useful in detecting muscle wasting in critically ill children but has not been shown to be sufficiently reliable in this population. Further study of the reliability and correlation with functional outcomes and nutrition intake is required before muscle ultrasound is routinely employed in critically ill children.

Functional Outcomes and Physical Impairments in Pediatric Critical Care Survivors: A Scoping Review.

OBJECTIVE: Although more children are surviving critical illness, little is known about long-term physical impairment. This scoping review aims to critically appraise existing literature on functional outcome measurement tools, prevalence, and risk factors for physical impairments in pediatric critical care survivors. DATA SOURCES: PubMed, Embase, and Cumulative Index to Nursing and Allied Health Literature, using a combination of MeSH terms and keywords (critical illness, intensive care, and functional outcomes/status). STUDY SELECTION: All human studies reporting functional outcomes in children 0-18 years old admitted to the PICU. Non-English language, adult and preterm infant studies were excluded. DATA SYNTHESIS: Three global assessment tools and eight multidimensional measures were used to measure functional outcome in pediatric survivors of critical illness. Rates of acquired functional impairment in a general pediatric intensive care cohort ranged from 10% to 36% at discharge and 10% to 13% after more than 2 years. Risk factors for acquired functional impairment include illness severity, the presence of organ dysfunction, length of ICU stay, and younger age. There is some evidence that physical impairment may be more severe and persistent than psychosocial components. CONCLUSIONS: Functional impairment may be persistent in pediatric survivors of critical care. Unfortunately, studies varied largely in measurement timing and tools used. The lack of differentiation between impairment in different functional domains limited the generalizability of data. Further studies using a combination of standardized measures at various time points of the disease process can help establish more comprehensive rates of physical impairment.

The transcription factor SOX6 contributes to the developmental origins of obesity by promoting adipogenesis.

An association between impaired fetal growth and the postnatal development of obesity has been established. Here, by comparing adipocytes differentiated from mesenchymal stem cells (MSCs) taken from the umbilical cord and derived from normal and growth-restricted neonates, we identified the transcription factor SOX6 as highly expressed only in growth-restricted individuals. We found that SOX6 regulates adipogenesis in vertebrate species by activating adipogenic regulators including PPARγ, C/EBPα and MEST. We further show that SOX6 interacts with ß-catenin in adipocytes, suggesting an inhibition of WNT/ß-catenin signaling, thereby promoting adipogenesis. The upstream regulatory region of the MEST gene in MSCs from growth-restricted subjects harbors hypomethylated CpGs next to SOX6 binding motifs, and we found that SOX6 binding is impaired by adjacent CpG methylation. In summary, we report that SOX6 is a novel regulator of adipogenesis synergizing with epigenetic mechanisms.

New measure of insulin sensitivity predicts cardiovascular disease better than HOMA estimated insulin resistance.

CONTEXT: Accurate assessment of insulin sensitivity may better identify individuals at increased risk of cardio-metabolic diseases. OBJECTIVES: To examine whether a combination of anthropometric, biochemical and imaging measures can better estimate insulin sensitivity index (ISI) and provide improved prediction of cardio-metabolic risk, in comparison to HOMA-IR. DESIGN AND PARTICIPANTS: Healthy male volunteers (96 Chinese, 80 Malay, 77 Indian), 21 to 40 years, body mass index 18-30 kg/m(2). Predicted ISI (ISI-cal) was generated using 45 randomly selected Chinese through stepwise multiple linear regression, and validated in the rest using non-parametric correlation (Kendall's tau τ). In an independent longitudinal cohort, ISI-cal and HOMA-IR were compared for prediction of diabetes and cardiovascular disease (CVD), using ROC curves. SETTING: The study was conducted in a university academic medical centre. OUTCOME MEASURES: ISI measured by hyperinsulinemic euglycemic glucose clamp, along with anthropometric measurements, biochemical assessment and imaging; incident diabetes and CVD. RESULTS: A combination of fasting insulin, serum triglycerides and waist-to-hip ratio (WHR) provided the best estimate of clamp-derived ISI (adjusted R(2) 0.58 versus 0.32 HOMA-IR). In an independent cohort, ROC areas under the curve were 0.77±0.02 ISI-cal versus 0.76±0.02 HOMA-IR (p>0.05) for incident diabetes, and 0.74±0.03 ISI-cal versus 0.61±0.03 HOMA-IR (p<0.001) for incident CVD. ISI-cal also had greater sensitivity than defined metabolic syndrome in predicting CVD, with a four-fold increase in the risk of CVD independent of metabolic syndrome. CONCLUSIONS: Triglycerides and WHR, combined with fasting insulin levels, provide a better estimate of current insulin resistance state and improved identification of individuals with future risk of CVD, compared to HOMA-IR. This may be useful for estimating insulin sensitivity and cardio-metabolic risk in clinical and epidemiological settings.