Adiponectin, ALT and family history as critical markers for the development of type 2 diabetes in obese Japanese children.

Aims/Introduction: An association between the pathogenesis of type 2 diabetes mellitus (T2D) and that of metabolic syndrome (MS) in obese children has been suggested. We clarified the critical markers for the development of T2D in obese Japanese children. Methods: One hundred and seven obese children who visited our outpatient clinic were enrolled in this study. The obese subjects were divided into 3 groups: Group A, T2D (n = 19); Group B, MS but not T2D (n = 19); and Group C: non-T2D, non-MS (n = 69). In all the subjects, a biochemical examination was performed and the serum adiponectin and leptin levels were measured. Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were measured using computed tomography images. Results: Group A tended to have higher VAT values and VAT/SAT ratios and lower leptin and adiponectin levels, compared with Groups B and C. In Group A, the alanine aminotransferase (ALT) level was significantly higher and the aspartate aminotransferase (AST)/ALT ratio was significantly lower than in Group C. A receiver operating characteristic (ROC) analysis showed that the optimal cut-off point for adiponectin was 6.4 µg/mL (AUC = 0.859). The cut-off points for ALT, the AST/ALT ratio and VAT were 35 IU/L (AUC = 0.821), 0.85 (AUC = 0.794) and 78 cm2 (AUC = 0.713), respectively. Group A had a significantly higher frequency of a family history of T2D than Group B. Conclusions: Our study revealed that the adiponectin level, ALT level, AST/ALT ratio, VAT value and a family history of T2D may be critical characteristic markers for T2D among obese Japanese children.

Characterization of AQP-2 gene mutation (R254Q) in a family with dominant nephrogenic DI.

We identified the AQP-2 gene mutation (R254Q) in a family with dominant NDI. The patient studied here has NDI with partial response to the anti-diuretic effect of AVP and dDAVP. Hereditary NDI seems to have the uniform clinical manifestations, but this might only reflect the information on screened patients with clear clinical presentations. It may be that a milder form of NDI has been overlooked due to a lack of genetic identification. Gene mutation analysis should be considered even in patients with mild NDI symptoms. Fortunately, both V2R and AQP2 genes are small and can be easily analyzed.

DEND syndrome due to V59A mutation in KCNJ11 gene: unresponsive to sulfonylureas.

Heterozygous activating mutations of KCNJ11 (Kir6.2) are the most common cause of permanent neonatal diabetes mellitus (NDM), and successful glycemic control has been obtained in several cases with oral sulfonylureas (SU). We have verified a lack of clinical response for both glycemic control and neurological features in an infant with permanent neonatal diabetes mellitus and DEND syndrome due to a V59A mutation in the KCNJ11 gene. Thus, our case reinforces that most cases with DEND syndrome are insensitive to SU.

[Evaluation of bone mineral density using digital image processing in children receiving anticonvulsants].

Bone mineral density (BMD) increases rapidly in a biphasic manner in childhood. During and after adolescence, BMD correlates more closely with bone age than chronological age. Digital image processing (DIP) allows the rapid assessment of BMD and bone age on one X-ray film. Herein, using DIP methods, the effects of various anticonvulsants on chronological and bone age were evaluated in 98 epilepsy patients (age range, 3-15 years) with no intellectual or motor disorders or diseases affecting bone metabolism. All patients were taking one or a combination of the following anticonvulsants: valproate sodium (VPA); carbamazepine (CBZ); and phenobarbital (PB). Bone maturation scores for radius-ulnar-short bones (RUS) were calculated using Tanner-Whitehouse 2 methods. Bone age was determined based on standard Japanese bone-maturation scores. In each patient, Z-scores for chronological and bone ages were calculated by subtracting standard BMD for gender and age from each BMD, then dividing the result by the standard deviation. The Z-score for each drug in relation to the administration period was analyzed using the Mann-Whitney test. For chronological age, significant differences in BMD were observed regarding the administration periods in children taking multiple drugs, but not in children on VPA, CBZ, or PB monotherapy. For bone age, no significant differences in BMD were observed regarding the administration periods for all drugs. Children taking multiple drugs showed a significant negative correlation between administration period and Z-scores for BMD calculated based on chronological age (Spearman rank correlation: - 0.457, p = 0.008), but not bone age. Among children receiving long-term VPA administration, bone age was delayed approximately 1 year, and bone maturation may have been delayed. No delay in bone age was noted among children receiving long-term administration of multiple drugs, suggesting that these anticonvulsants do not influence bone maturity. These findings indicate that bone age should be considered when assessing BMD.

Genetic factors and clinical significance of acanthosis nigricans in obese Japanese children and adolescents.

AIM: To clarify the clinical significance of acanthosis nigricans (AN) and the association of gene polymorphisms in the ss2- and ss3-adrenergic receptors (B2ADR and B3ADR) in Japanese obese children and adolescents. METHODS: Seventy obese subjects (56 boys, 14 girls) from 5 to 19 y of age were examined as to clinical features. Genetic analyses were performed in 83 obese subjects (61 boys, 22 girls), 2 to 17 y of age. Typing of gene polymorphisms in B2ADR and B3ADR was achieved by polymerase chain reaction (PCR) of genomic DNA and restriction fragment-length polymorphism analysis (PCR-RFLP). RESULTS: The group with AN (n = 30) had higher values for percent overweight, BMI, waist circumference, fasting insulin, HOMA-R, leptin and PAI-1 than the AN-negative group (n = 40), but there were no significant differences in age, sex or percent body fat between the two groups. The prevalences of B2ADR Gly16 and B3ADR Arg64 were significantly higher in AN-positive (n = 26) than in AN-negative (n = 57) subjects. In addition, the AN frequency was significantly higher in the group with both Gly16 and Arg64 than in the group with neither of these alleles (55.6% vs 12.5%, p < 0.05). CONCLUSION: We demonstrate that AN is a useful clinical marker for the severity of obesity associated with a high BMI, and that B2ADR Gly16 and B3ADR Arg64 are associated synergistically with AN in obese children and adolescents.

Short-term secretory regulation of ghrelin during growth hormone provocative tests in prepubertal children with various growth hormone secretory capacities.

BACKGROUND AND OBJECTIVE: Ghrelin is a novel gastric peptide which stimulates GH secretion and has been demonstrated to have orexigenic and adipogenic properties. Insulin is a physiological and dynamic modulator of plasma ghrelin, and insulinemia possibly mediates the effect of the nutritional state on the plasma concentrations of ghrelin in adults. No data on the regulation of GH secretion by ghrelin have so far been reported, nor has the possible influence of hypoglycemia on the plasma ghrelin levels in children been reported. METHODS: Provocative studies were performed using a variety of stimuli, including insulin-induced hypoglycemia, and glucagon, arginine and L-dopa loading. We studied a group of 27 children with short stature being investigated for GH deficiency (10 F, 17 M; age 4-14 years; height SDS -0.92 to -3.27); the subjects were instructed to fast overnight, and the following morning, the relationships among the plasma ghrelin, GH and glucose levels were investigated by determining the plasma ghrelin profiles during those provocative tests. Using a new method for determining the two types of ghrelin, samples were obtained for determination of the plasma ghrelin, serum glucose and serum GH levels after the administration of the aforementioned stimulating agents. RESULTS: All the four stimuli caused a significant decrease in the circulating C- and N-ghrelin levels with a nadir at +30 min, with the exception of the N-ghrelin level following the L-dopa loading. During the same period, the plasma GH level increased following insulin, arginine and L-dopa loading, and the plasma glucose level increased significantly following glucagon loading. In the arginine and L-dopa load connected, a significant correlation was observed between the 30-min change in the serum GH level and the 30-min change in the plasma C-ghrelin level. In the multiple regression analysis to explain the 30-min change in the plasma level of C-ghrelin, the baseline plasma level of C-ghrelin (basal), height and % overweight were the only three significant parameters, accounting for 85.2% of the variance. CONCLUSION: This study demonstrated that the inverse relation between the circulating GH and ghrelin levels may indicate the existence of a feedback loop, and also lends support to the assumption of a GH-independent relationship between plasma ghrelin and glucose levels. These observations constitute further evidence to suggest that peripheral ghrelin is a direct growth-promoting hormone.

Association of HLA-DR, -DQ genotype and CTLA-4 gene polymorphism with Graves' disease in Japanese children.

OBJECTIVE: Childhood onset Graves' disease (GD) has been documented to be clinically distinct from adult onset GD, and an association with the genes encoding HLA and CTLA-4 (cytotoxic T lymphocyte antigen-4) has been reported in both Caucasian and Japanese adult GD patients. The aim of this study was to determine whether HLA-DR, -DQ and CTLA-4 are associated with childhood onset GD in Japanese individuals. METHODS: We investigated the genotype of HLA class II (DRB1, DQB1) and the A/G transition polymorphism of CTLA-4 exon 1 position 49 in 43 GD patients and in healthy controls for comparison. The CTLA-4 alleles were identified by the polymerase chain reaction (PCR) of genomic DNA and restriction fragment-length polymorphism analysis (PCR-RFLP) with Ita1. RESULTS: The frequency of both HLA-DRB1*0405 and DQB1*0401 was increased in the patient group (DRB1*0405: 26.7%, p < 0.001; DQB1*0401: 25.6%, p < 0.005) compared with the controls. Patients with GD had a significantly lower frequency of the AA genotype of CTLA-4 than the controls, but there was no difference in allele frequency between the G and A allele. CONCLUSIONS: the association of HLA-DRB1 and DQB1 genotype with susceptibility to childhood onset GD differs from that in adult onset GD, whereas the association between CTLA-4 gene polymorphism and childhood onset GD is similar to that in adult onset GD in Japanese individuals, but the association is weak.

Absence of Heterozygous K83E and R257X Mutations of the AIRE-1 Gene in 46 Children with Type 1 Diabetes and 44 Children with Graves' Disease.

Type 1 diabetes mellitus (DM) and Graves' disease are autoimmune diseases, and a number of genetic factors, including HLA and CTLA-4 genes, have been reported to contribute to their etiology. The gene responsible for autoimmune polyendocrinopathy- candidiasis-ectodermal dystrophy (APECED) has been cloned and named the autoimmune regulator-1 (AIRE-1) gene. AIRE-1 protein is thought to be a transcription regulatory protein and to have a role in the maintenance of immunological tolerance. The aim of this study was to determine whether heterozygous AIRE-1 gene mutations are associated with childhood-onset type 1 diabetes and Graves' disease in the Japanese population. We investigated 46 children with type 1 DM (29 females and 17 males; age at the time of diagnosis, 0.5-16 yr) and 44 children with Graves' disease (34 females and 10 males; age at the time of diagnosis, 3-16 yr) for the presence of the K83E mutation in exon 2 and the R257X mutation in exon 6 of the AIRE-1 gene. The alleles were identified by polymerase chain reaction of genomic DNA and restriction fragment-length polymorphism analysis (PCR-RFLP) with endonuclease TaqI. Since no patients with type 1 DM or Graves' disease were found to carry the K83E or the R257X heterozygous mutation, we concluded that neither the K83E nor the R257X heterozygous mutation in the AIRE-1 gene seem to be the cause of the more common isolated endocrinopathies, i.e., type 1 diabetes mellitus and Graves' disease, in Japanese children.

Fasting plasma ghrelin levels are negatively correlated with insulin resistance and PAI-1, but not with leptin, in obese children and adolescents.

Ghrelin is a novel growth hormone-releasing peptide isolated from human and rat stomach that induces weight gain by increasing food intake and reducing fat utilization. Although recent data indicate that ghrelin is downregulated in human adult obesity, the characteristics of human obesity are heterogeneous, especially in children and adolescents, and depend on the distribution of subcutaneous and visceral fat tissue. We measured fasting plasma ghrelin concentrations by radioimmunoassay in 49 obese Japanese children and adolescents (38 boys and 11 girls; mean age 10.2 +/- 2.8 years; BMI 28.0 +/- 4.5 kg/m(2), percent overweight 56.0 +/- 20.7%), and analyzed associations of their ghrelin concentrations with their body composition, insulin resistance, and adipocytokine concentrations. Fasting plasma ghrelin levels were negatively correlated with BMI and waist circumference, but not with percent overweight or percent body fat, whereas fasting leptin levels were positively correlated with all of the following parameters: BMI, waist circumference, percent overweight, and percent body fat. Plasma ghrelin levels were negatively correlated with fasting immunoreactive insulin, homeostasis model assessment insulin resistance index, and quantitative insulin sensitivity check index values. There was no correlation between plasma ghrelin and leptin, but ghrelin was negatively correlated with the PAI-1 concentrations. The results suggest that the downregulation of ghrelin secretion may be a consequence of higher insulin resistance associated with visceral fat accumulation and elevated PAI-1 concentrations, and not a consequence of total body fat accumulation associated with elevated leptin concentrations.

Impact of polymorphisms of human beta-adrenergic receptor gene on changes in height during growth hormone treatment.

The aim of this study was to investigate the occurrence of polymorphisms of the beta-adrenergic receptor gene in short children and to evaluate the possible influence of the polymorphisms on changes in height and obesity index in response to GH treatment. Of the 75 children enrolled in the study, 40 completed at least 5 years of GH treatment. The genotype distribution of the beta2 and 3-adrenergic receptor polymorphisms in the study population did not differ significantly from those reported in non-obese subjects. There were no significant differences in the SD score for height at any given time-point between the group with and without the Trp64Arg mutation of the beta3-adrenergic receptor gene. In relation to the Glyl6Arg polymorphism of the beta2-adrenergic receptor gene, the mean SD score for height increased significantly during GH treatment in children with Argl6Arg and Glyl6Arg. In those with Glyl6Gly, the score did not show any significant increase during all 5 years of GH treatment. In both the groups with and without the Trp64Arg mutation, the changes in obesity index did not reach statistical significance at any time-point. Only children with Glyl6Gly had a significantly higher baseline mean obesity index than those with Glyl6Arg. The index also decreased markedly from 21.9% to 5.8% in these children during the first 4 years of GH treatment. Thus, when the impact of the polymorphisms of these two receptor genes was studied simultaneously, it appeared that only the beta2-adrenergic receptor polymorphism had an important role to play in modulating the regulation of growth rate and energy expenditure in short children.