Establishing reference values for percentage of appendicular skeletal muscle mass and their association with metabolic syndrome in Korean adolescents.

PURPOSE: The association between appendicular skeletal muscle mass (ASM) and cardiometabolic risk has been emphasized. We estimated reference values of the percentage of ASM (PASM) and investigated their association with metabolic syndrome (MS) in Korean adolescents. METHODS: Data from the Korea National Health and Nutrition Examination Survey performed between 2009 and 2011 were used. Tables and graphs of reference PASM were generated using 1,522 subjects, 807 of whom were boys aged 10 to 18. The relationship between PASM and each component of MS in adolescents was further analyzed in 1,174 subjects, 613 of whom were boys. Moreover, the pediatric simple MS score (PsiMS), the homeostasis model assessment of insulin resistance (HOMA-IR), and the triglyceride-glucose (TyG) index were analyzed. Multivariate linear and logistic regressions adjusting for age, sex, household income, and daily energy intake were performed. RESULTS: In boys, PASM increased with age; the trend was different in girls, in whom PASM declined with age. PsiMS, HOMA-IR, and TyG index showed inverse associations with PASM (PsiMS, ß=-0.105, P<0.001; HOMA-IR, ß=-0.104, P<0.001; and TyG index, ß=-0.013, P<0.001). PASM z-score was negatively associated with obesity (adjusted odds ratio [aOR], 0.22; 95% CI, 0.17-0.30), abdominal obesity (aOR, 0.27; 95% CI, 0.20-0.36), hypertension (aOR, 0.65; 95% CI, 0.52-0.80), and elevated triglycerides (aOR, 0.67; 95% CI, 0.56-0.79). CONCLUSION: The probability of acquiring MS and insulin resistance decreased as PASM values increased. The reference range may offer clinicians information to aid in the effective management of patients. We urge clinicians to monitor body composition using standard reference databases.

Relationship Between the Serum FGF21 Level and Growth in Children of Short Stature.

BACKGROUND: This study investigated the relationship between fibroblast growth factor 21 (FGF21) levels and growth in children with growth hormone deficiency (GHD) and idiopathic short stature (ISS), and the effects of the FGF21 level on response to growth hormone (GH) treatment. METHODS: We included 171 pre-pubertal children with a GHD (n = 54), ISS (n = 46), and normal height (n = 71). Fasting FGF21 levels were measured at baseline and every 6 months during GH treatment. Factors associated with growth velocity (GV) after GH therapy were investigated. RESULTS: The FGF21 level was higher in short children than in the controls without significant difference between the GHD and ISS groups. In the GHD group, the FGF21 level was inversely associated with the free fatty acid (FFA) level at baseline (r = -0.28, P = 0.039), however, was positively correlated with the FFA level at 12 months (r = 0.62, P = 0.016). The GV over 12 months of GH therapy was positively associated with the delta insulin-like growth factor 1 level (ß = 0.003, P = 0.020). The baseline log-transformed FGF21 level was inversely associated with GV with marginal significance (ß = -0.64, P = 0.070). CONCLUSION: The FGF21 level was higher in children of short stature, both those with GHD and the ISS, than in children with normal growth. The pretreatment FGF21 level negatively affected the GV of children with GH-treated GHD. These results suggest the existence of a GH/FFA/FGF21 axis in children.

Distinct Clinical and Laboratory Features of COVID-19 in Children During the Pre-Delta, Delta and Omicron Wave.

BACKGROUND: The SARS-CoV-2 variants of concern exhibit distinct features in terms of transmissibility and virulence. This study compared the clinical characteristics of COVID-19 in children during pre-Delta, Delta and Omicron waves. METHODS: Medical records of 1163 children <19 years of age with COVID-19 admitted to a designated hospital in Seoul, South Korea, were analyzed. Clinical and laboratory findings during the pre-Delta (March 1, 2020, to June 30, 2021; 330 children), Delta (July 1, 2021, to December 31, 2021; 527 children) and Omicron (January 1, 2022, to May 10, 2022; 306 children) waves were compared. RESULTS: Children during the Delta wave were older and had a higher proportion of fever ≥5 days and pneumonia than children during the pre-Delta and Omicron waves. The Omicron wave was characterized by younger age and a higher proportion of fever ≥39.0 °C, febrile seizure and croup. More children <2 years of age and adolescents aged 10 to <19 years experienced neutropenia and lymphopenia, respectively, during the Delta wave. Children aged 2 to <10 years had a higher incidence of leukopenia and lymphopenia during the Omicron wave. CONCLUSIONS: Distinct features of COVID-19 were observed in children during the Delta and Omicron surges. Continuous scrutiny of the manifestations of variants of concern is needed for appropriate public health response and management.

Relationship between prolactin level and puberty in girls with early breast development.

OBJECTIVES: Prolactin (PRL) stimulates the mammary glands development; however, it also inhibits gonadotropin-releasing hormone (GnRH) secretion. We evaluated the relationship between PRL levels and puberty in girls with precocious breast development. METHODS: This study included 244 girls with breast development < 8 years of age. Patients were categorized as central precocious puberty (CPP) [peak luteinizing hormone (LH) levels ≥ 5 IU/L after GnRH stimulation] versus non-CPP (NPP) group. High PRL was defined as serum PRL > 17.9 ng/mL. RESULTS: High PRL was more common in NPP than in CPP group (17.6 vs. 8.1%, p=0.025), although mean PRL levels did not differ. In NPP group, the high PRL group had lower peak LH/follicle-stimulating hormone (FSH) ratio, and later LH peak time after GnRH stimulation than normal PRL group (all p < 0.05). PRL levels of the subgroups according to the peak LH time (15, 30, 45, 60, and 90 min after GnRH stimulation) were different in NPP group, but not in CPP group. PRL levels tended to be higher as the peak LH time was delayed. High PRL was associated with decreased odds for CPP (OR=0.42, p=0.043). CONCLUSIONS: Girls with NPP showed higher proportion of high PRL than CPP group. High PRL group showed more features of prepubertal response in NPP group, and associated with decreased odds for CPP, suggesting the possibility of PRL role on breast development while suppressing hypothalamic-pituitary-gonadal axis activation in NPP girls.

Croup as a Manifestation of SARS-CoV-2 Omicron Variant Infection in Young Children.

Croup is an acute upper respiratory disease primarily caused by the parainfluenza virus. Owing to inflammation and edema of the upper airways, children present with barky cough and stridor, and some may experience respiratory distress. We investigated children aged < 5 years with coronavirus disease 2019 (COVID-19) admitted to two hospitals in Seoul, South Korea, and observed a spike in croup cases during the omicron surge. Among the 569 children admitted from March 1, 2021 to February 25, 2022, 21 children (3.7%) had croup, and the proportion of croup cases was significantly higher during the omicron wave than that during the delta wave (12.4% vs. 1.2%, P < 0.001). With the immediate administration of corticosteroids and epinephrine via nebulizer, the symptoms improved rapidly. During the current omicron surge, careful monitoring of the symptoms of croup in young children is needed for the diagnosis of COVID-19 and its timely management.

Glutamic Acid Decarboxylase and Tyrosine Phosphatase-Related Islet Antigen-2 Positivity among Children and Adolescents with Diabetes in Korea.

Autoantibodies against glutamic acid decarboxylase (GADA), tyrosine phosphatase-related islet antigen 2 (IA2A), insulin (INSA), and islet cells (ICA) are critical for determining the type of diabetes and management strategy in new-onset diabetes mellitus (NODM), but there have been few reports of all diabetes-associated autoantibody (DAA) in Korea. We retrospectively analyzed 193 patients with NODM aged 0 to 18 years who were followed at two tertiary centers in Korea (2017 to 2021). Patients with type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) were 93 (48.2%) and 100 (51.8%), respectively. In T1DM patients, the DAA positivity rate was 94.6%; prevalence of GADA, IA2A, INSA, and ICA was 71.0%, 71.0%, 31.2%, and 10.8%, respectively; and IA2A added 10.7% point autoantibody positivity (83.9% for GADA+INSA+ICA and 94.6% for GADA+INSA+ICA+IA2A). Among the patients with T2DM, 12 (12.0%) were positive for DAA, and all were positive for INSA. These findings suggest that DAA at diagnosis, especially GADA and IA2A, is useful for classifying diabetes in Korean children and adolescents.

Temporal Trends for Diabetes Management and Glycemic Control Between 2010 and 2019 in Korean Children and Adolescents with Type 1 Diabetes.

Purpose: There is increasing use of modern devices in the management of patients with type 1 diabetes (T1D). We investigated temporal trends for diabetes management and outcomes in Korean pediatric T1D patients over 10 years. Methods: We retrospectively collected the data from 752 participants (boys: 311, 41.4%) diagnosed with T1D and aged ≤18 years, with ≥1 year of follow-up between 2010 and 2019 in any of the seven study hospitals in Korea. Results: Over the 10-year study period, use of continuous glucose monitoring (CGM) increased from 1.4% to 39.3%. From 2010 to 2019, there was an increased use of multiple daily insulin injections (MDI; 63.9%-77.0%, respectively) and continuous subcutaneous insulin infusion (CSII; 2.1%-14.0%, respectively), but decreased use of conventional insulin therapy (CIT, 33.9%-9.0%, respectively). Mean glycated hemoglobin (HbA1c) decreased from 8.56% to 8.01% (P < 0.001) and was lower in younger patients, boys, and CGM users (P < 0.001). MDI and CSII users had lower mean HbA1c levels than CIT users (P = 0.003). Regarding the acute complications of T1D, CGM use was associated with lower incidences of diabetic ketoacidosis (P = 0.015); CSII users were likely to experience less severe hypoglycemia (P = 0.008). Conclusions: The use of CSII and CGM increased ∼7- and 30-fold, respectively, over the 10-year study period. The glycemic control of pediatric T1D patients in Korea improved from 2010 to 2019, probably because of increased use of T1D technologies.

High-Sensitivity C-Reactive Protein Is Associated with Prediabetes and Adiposity in Korean Youth.

Background: Obesity, a chronic low-grade inflammatory state, increases the risk of cardiovascular disease. Elevated high-sensitivity C-reactive protein (hs-CRP) levels are associated with cardiovascular disease, type 2 diabetes, and metabolic syndrome in adults. This study aimed to determine the association of hs-CRP and cardiometabolic risk factors, including obesity, prediabetes, hypertension, and dyslipidemia, in the nationally representative data of Korean youth. Methods: Anthropometric, biochemical, physical activity (PA), and nutritional survey data were collected for 1,723 youths (918 boys, 53.5%), aged 10-18 years, from the Korea National Health and Nutrition Examination Survey (2015-2017). Participants were classified into three groups according to hs-CRP tertile. Abdominal obesity, impaired fasting glucose, elevated triglyceride, decreased high-density lipoprotein (HDL) cholesterol and elevated blood pressure, and prediabetes [glycated hemoglobin (HbA1c) 5.7%-6.4%] were compared according to sex and hs-CRP tertile. Results: The ranges of each hs-CRP tertile were ≤0.3, 0.31-0.5, and >0.5 mg/L, respectively. hs-CRP was positively associated with body mass index (BMI) z-score (P < 0.001) and HbA1c (P = 0.012), and negatively with HDL cholesterol (P = 0.029), after adjusting confounding variables, including age, sex, BMI, white blood cell count, PA, and nutritional factors. The upper tertile of hs-CRP was associated with obesity [adjusted odds ratio (aOR) 12.07, P < 0.001] and prediabetes (aOR 3.08, P = 0.002). Conclusions: Elevated hs-CRP is associated with high BMI z-score and HbA1c, and low HDL cholesterol in Korean children and adolescents. Hence, hs-CRP could be a reliable indicator for adiposity, prediabetes, and abnormal lipid metabolism in the pediatric population.

Discrepancies between Glycosylated Hemoglobin and Fasting Plasma Glucose for Diagnosing Impaired Fasting Glucose and Diabetes Mellitus in Korean Youth and Young Adults.

BACKGROUND: Glycosylated hemoglobin (HbA1c) has been recommended as a diagnostic test for prediabetes and diabetes. Here, we evaluated the level of agreement between diagnoses based on fasting plasma glucose (FPG) versus HbA1c levels and determined optimal HbA1c cutoff values for these diseases in youth and young adults. METHODS: The study included 7,332 subjects (n=4,129, aged 10 to 19 years in youth group; and n=3,203 aged 20 to 29 years in young adult group) from the 2011 to 2016 Korea National Health and Nutrition Examination Survey. Prediabetes and diabetes were defined as 100 to 125 mg/dL (impaired fasting glucose [IFG]) and ≥126 mg/dL for FPG (diabetes mellitus [DM] by FPG [DMFPG]), and 5.7% to 6.4% and ≥6.5% for HbA1c, respectively. RESULTS: In the youth group, 32.5% with IFG had an HbA1c level of 5.7% to 6.4%, and 72.2% with DMFPG had an HbA1c ≥6.5%. In the young adult group, 27.5% with IFG had an HbA1c level of 5.7% to 6.4%, and 66.6% with DMFPG had an HbA1c ≥6.5%. Kappa coefficients for agreement between the FPG and HbA1c results were 0.12 for the youth group and 0.19 for the young adult group. In receiver operating characteristic curve analysis, the optimal HbA1c cutoff for IFG and DMFPG were 5.6% and 5.9% in youths and 5.5% and 5.8% in young adults, respectively. CONCLUSION: Usefulness of HbA1c for diagnosis of IFG and DMFPG in Koreans aged <30 years remains to be determined due to discrepancies between the results of glucose- and HbA1c-based tests. Additional testing might be warranted at lower HbA1c levels to detect IFG and DMFPG in this age group.

Distribution of glycated haemoglobin and its determinants in Korean youth and young adults: a nationwide population-based study.

The present study aimed to describe the distribution of and to investigate the factors associated with glycated haemoglobin (HbA1c) values in Korean youth (10-19 years old) and young adults (20-29 years old). Data from the Korea Health and Nutrition Examination Survey (2011-2015) were used. A total of 6,418 participants (male 3,140 [53.2%]) aged 10-29 years were included in the analysis. Percentiles of HbA1c were calculated and HbA1c values were compared according to age, sex, and associated factors. The mean HbA1c values (% [mmol/mol]) were 5.42 ± 0.01 (35.7 ± 0.1) for youths and 5.32 ± 0.01 (34.7 ± 0.1) for young adults (P < 0.001). Male participants showed significantly higher HbA1c level than females (P < 0.001). When age was grouped into 5-year intervals, HbA1c was the highest in those aged 10-14 years and the lowest in those aged 20-24 years. After controlling for confounding variables, the HbA1c values of youths and male participants were significantly higher than those of young adults and female participants. The present study provides nationally representative data on the distribution of HbA1c values in Korean youth and young adults. There were significant differences in the level of HbA1c according to age and sex.

Association between hemoglobin glycation index and cardiometabolic risk factors in Korean pediatric nondiabetic population.

PURPOSE: The hemoglobin glycation index (HGI) represents the degree of nonenzymatic glycation and has been positively associated with cardiometabolic risk factors (CMRFs) and cardiovascular disease in adults. This study aimed to investigate the association between HGI, components of metabolic syndrome (MS), and alanine aminotransferase (ALT) in a pediatric nondiabetic population. METHODS: Data from 3,885 subjects aged 10-18 years from the Korea National Health and Nutrition Examination Survey (2011-2016) were included. HGI was defined as subtraction of predicted glycated hemoglobin (HbA1c) from measured HbA1c. Participants were divided into 3 groups according to HGI tertile. Components of MS (abdominal obesity, fasting glucose, triglycerides, high-density lipoprotein cholesterol, and blood pressure), and proportion of MS, CMRF clustering (≥2 of MS components), and elevated ALT were compared among the groups. RESULTS: Body mass index (BMI) z-score, obesity, total cholesterol, ALT, abdominal obesity, elevated triglycerides, and CMRF clustering showed increasing HGI trends from lower-to-higher tertiles. Multiple logistic regression analysis showed the upper HGI tertile was associated with elevated triglycerides (odds ratio, 1.65; 95% confidence interval, 1.18-2.30). Multiple linear regression analysis showed HGI level was significantly associated with BMI z-score, HbA1c, triglycerides, and ALT. When stratified by sex, age group, and BMI category, overweight/obese subjects showed linear HGI trends for presence of CMRF clustering and ALT elevation. CONCLUSION: HGI was associated with CMRFs in a Korean pediatric population. High HGI might be an independent risk factor for CMRF clustering and ALT elevation in overweight/obese youth. Further studies are required to establish the clinical relevance of HGI for cardiometabolic health in youth.

Factors Associated with the Presence and Severity of Diabetic Ketoacidosis at Diagnosis of Type 1 Diabetes in Korean Children and Adolescents.

The aim of this study was to identify the risk factors for presence and severity of diabetic ketoacidosis (DKA) at the onset of type 1 diabetes mellitus (T1DM) in Korean children and adolescents. A retrospective chart review of children and adolescents newly diagnosed with T1DM was conducted in seven secondary and tertiary centers in Korea. Eligible subjects were < 20 years of age and had records on the presence or absence of DKA at the time of T1DM diagnosis. DKA severity was categorized as mild, moderate, or severe. Data were collected on age, height, body weight, pubertal status, family history of diabetes, delayed diagnosis, preceding infections, health insurance status, and parental education level. A total of 361 patients (male 46.3%) with T1DM were included. Overall, 177 (49.0%) patients presented with DKA at T1DM diagnosis. Risk factors predicting DKA at T1DM diagnosis were age ≥ 12 years, lower serum C-peptide levels, presence of a preceding infection, and delayed diagnosis. Low parental education level and preceding infection increased the severity of DKA. These results suggest that alertness of the physician and public awareness of diabetes symptoms are needed to decrease the incidence and severity of DKA at T1DM diagnosis.

Unfavorable Course of Subclinical Hypothyroidism in Children with Hashimoto's Thyroiditis Compared to Those with Isolated Non-Autoimmune Hyperthyrotropinemia.

Subclinical hypothyroidism (SCH) is a common problem in pediatric population, and the natural history of SCH varies depending on its etiology. Whether Hashimoto's thyroiditis (HT) negatively affects the natural course of SCH was investigated in pediatric patients without concomitant diseases. Predictors for levothyroxine medication were also evaluated. Medical records of 109 children with SCH (91 girls, 5?18 years) diagnosed between 2005 and 2014 were retrospectively reviewed. Patients were classified into HT (n = 37) and isolated non-autoimmune hyperthyrotropinemia (iso-NAHT, n = 72). During median 2 years of follow-up, only 10.1% of SCH patients eventually initiated levothyroxine, and HT patients showed a higher probability of requiring levothyroxine medication than iso-NAHT patients (21.6% vs. 4.2%). Underlying HT independently predicted deterioration of thyroid function, leading to levothyroxine medication (hazard ratios [HRs], 4.6 vs. iso-NAHT, P = 0.025). High titers of anti-thyroglobulin antibodies (TGAbs) predicted later medication in the HT group (HRs, 28.2 vs. normal TGAbs, P = 0.013). Most pediatric SCH showed benign and self-remitting courses. Underlying HT significantly increases the risk for levothyroxine medication, especially with high titers of TGAbs.

Perinatal factors associated with neonatal thyroid-stimulating hormone in normal newborns.

PURPOSE: This study was to evaluate the effect of neonatal, maternal, and delivery factors on neonatal thyroid-stimulating hormone (TSH) of healthy newborns. METHODS: Medical records of 705 healthy infants born through normal vaginal delivery were reviewed. Neonatal TSH levels obtained by neonatal screening tests were analyzed in relation to perinatal factors and any associations with free thyroxine (FT4) and 17-α hydroxyprogesterone (17OHP) levels. RESULTS: An inverse relationship was found between TSH and sampling time after birth. Twin babies and neonates born by vacuum-assisted delivery had higher TSH levels than controls. First babies had higher TSH levels than subsequent babies. Birth weight, gestational age, maternal age and duration from the rupture of the membrane to birth were not related to neonatal TSH. There were no significant differences in TSH level according to sex, Apgar scores, labor induction, the presence of maternal disease and maternal medications. There was a positive association between TSH and 17OHP level but not between TSH and FT4 level. Multiple linear regression analyses showed that sampling time, mode of delivery, birth order, and 17OHP level were significant factors affecting neonatal TSH level. CONCLUSION: Neonatal TSH levels of healthy normal newborns are related with multiple factors. Acute stress during delivery may influence the neonatal TSH level in early neonatal period.

Clinical and radiological features of pituitary stalk lesions in children and adolescents.

PURPOSE: The diagnosis of pituitary stalk lesion has been based on clinical feature, radiologic assessment for its critical location and role. This study aimed to investigate clinical symptoms, endocrine disturbance, magnetic resonance imaging (MRI) findings of pituitary stalk lesions in children and adolescents and to evaluate differences between neoplastic lesions with the others. METHODS: We performed a retrospective review of patients under 18 years old with pituitary stalk lesions diagnosed at the Seoul National University Children's Hospital between 2000 and 2013, by a text search for head MRI reports by using 'pituitary stalk', 'infundibulum', and 'infundibular stalk', as keywords. RESULTS: For the 76 patients, sixteen patients (21.1%) had congenital lesions, and 52 (68.4%) had neoplasms. No inflammatory lesions were found. Diabetes insipidus (DI) was the most common endocrine defect, diagnosed in 38 patients (50%). There was male predominance especially in neoplastic group. Thickened pituitary stalk was, but enhancement of lesion was not, associated with neoplasm. DI was more prevalent in neoplastic stalk lesions. Anterior pituitary dysfunction such as growth hormone and adrenocorticotropic hormone deficiencies were less prevalent in neoplastic lesions of pituitary stalk. CONCLUSION: In conclusion, the etiology of pituitary stalk lesions in children and adolescents is diverse and different from that in adults. Neoplastic pituitary stalk lesions can be differentiated from nonneoplastic lesions by systemic evaluation of clinical, hormonal, radiological findings.

Influence of body mass index on the growth hormone response to provocative testing in short children without growth hormone deficiency.

Obesity and its related factors are known to suppress the secretion of growth hormone (GH). We aimed to evaluate the influence of body mass index (BMI) on the peak GH response to provocative testing in short children without GH deficiency. We conducted a retrospective review of medical records of 88 children (2-15 yr old) whose height was less than 3 percentile for one's age and sex, with normal results (peak GH level > 10 ng/mL) of GH provocative testing with clonidine and dopamine. Peak stimulated GH level, height, weight, pubertal status and serum IGF-1 level were measured. Univariate analysis showed that the BMI standard deviation score (SDS) correlated negatively with the natural log (ln) of the peak stimulated GH level (ln peak GH). BMI SDS did not correlate significantly with sex, age, pubertal status, or ln IGF-1 level. BMI SDS correlated negatively with ln peak GH level induced by clonidine but not by dopamine. In stepwise multivariate regression analysis, BMI SDS was the only significant predictor of ln peak GH level in the combination of tests and the clonidine test, but not in the dopamine test. In children without GH deficiency, BMI SDS correlates negatively with the peak GH level. BMI SDS should be included in the analysis of the results of GH provocation tests, especially tests with clonidine.

Growth after hematopoietic stem cell transplantation in children with acute myeloid leukemia.

Previous studies have shown that hematopoietic stem cell transplantation (HSCT) may result in growth impairment. The purpose of this study was to evaluate the growth during 5 yr after HSCT and to determine factors that influence final adult height (FAH). We retrospectively reviewed the medical records of acute myeloid leukemia (AML) patients who received HSCT. Among a total of 37 eligible patients, we selected 24 patients who began puberty at 5 yr after HSCT (Group 1) and 19 patients who reached FAH without relapse (Group 2). In Group 1, with younger age at HSCT, sex, steroid treatment, hypogonadism and hypothyroidism were not significantly associated with growth impairment 5 yr after HSCT. History of radiotherapy (RT) significantly impaired the 5 yr growth after HSCT. Chronic graft-versus-host disease (cGVHD) only temporarily impaired growth after HSCT. In Group 2, with younger age at HSCT, steroid treatment and hypogonadism did not significantly reduce FAH. History of RT significantly reduced FAH. Growth impairment after HSCT may occur in AML patients, but in patients without a history of RT, growth impairment seemed to be temporary and was mitigated by catch-up growth.

Urinary 6-sulfatoxymelatonin level in girls and its relationship with obesity.

PURPOSE: Short sleep duration is associated with obesity. Urinary 6-sulfatoxymelatonin (6-OHMS), the principal metabolite of melatonin, is closely related with sleep. We evaluated the difference in urinary 6-OHMS levels between obese girls and normal weight girls, and the relationship of urinary 6-OHMS with other hormones regulating body weight and metabolism. METHODS: A total of 79 girls (6.3 to 12.4 years) were included in this study, of whom 34 were obese; 15, overweight; and 30, normal-weight. We examined their pubertal status and bone age. Fasting serum levels of total ghrelin, leptin, insulin, and first morning urinary 6-OHMS were measured. Homeostatic model assessment-insulin resistance (HOMA-IR) was calculated from the fasting insulin and glucose levels. RESULTS: There was no significant difference in the creatinine adjusted 6-OHMS levels between the obese girls and the control group. Urinary 6-OHMS did not show any correlations with body mass index (BMI), BMI percentile, total ghrelin, leptin, and HOMA-IR. Negative correlations were found between urinary 6-OHMS levels and chronological and bone ages. CONCLUSION: Our results suggest that melatonin production is not reduced consistently in obese girls.

Signalling through the type 1 insulin-like growth factor receptor (IGF1R) interacts with canonical Wnt signalling to promote neural proliferation in developing brain.

Signalling through the IGF1R [type 1 IGF (insulin-like growth factor) receptor] and canonical Wnt signalling are two signalling pathways that play critical roles in regulating neural cell generation and growth. To determine whether the signalling through the IGF1R can interact with the canonical Wnt signalling pathway in neural cells in vivo, we studied mutant mice with altered IGF signalling. We found that in mice with blunted IGF1R expression specifically in nestin-expressing neural cells (IGF1RNestin-KO mice) the abundance of neural ß-catenin was significantly reduced. Blunting IGF1R expression also markedly decreased: (i) the activity of a LacZ (ß-galactosidase) reporter transgene that responds to Wnt nuclear signalling (LacZTCF reporter transgene) and (ii) the number of proliferating neural precursors. In contrast, overexpressing IGF-I (insulin-like growth factor I) in brain markedly increased the activity of the LacZTCF reporter transgene. Consistently, IGF-I treatment also markedly increased the activity of the LacZTCF reporter transgene in embryonic neuron cultures that are derived from LacZTCF Tg (transgenic) mice. Importantly, increasing the abundance of ß-catenin in IGF1RNestin-KO embryonic brains by suppressing the activity of GSK3ß (glycogen synthase kinase-3ß) significantly alleviated the phenotypic changes induced by IGF1R deficiency. These phenotypic changes includes: (i) retarded brain growth, (ii) reduced precursor proliferation and (iii) decreased neuronal number. Our current data, consistent with our previous study of cultured oligodendrocytes, strongly support the concept that IGF signalling interacts with canonical Wnt signalling in the developing brain to promote neural proliferation. The interaction of IGF and canonical Wnt signalling plays an important role in normal brain development by promoting neural precursor proliferation.