Pubertal patterns in children with sickle cell anemia: A case-control study in Cameroon

BACKGROUND

Puberty may be impaired in children with sickle cell anemia (SCA). Therefore, we aimed to explore the clinical and hormonal features of puberty in Cameroonian children.

METHODS

In a case-control study, we included 64 children aged 8-18 years with SCA matched to healthy controls. We assessed height, weight, body mass index, body composition, and Tanner stages. Hormonal measurements included anti-mullerian hormone, follicle-stimulating hormone, luteinizing hormone, and sex hormones (estrogens/testosterone). We used the Mann-Whitney Wilcoxon test to compare the median values between cases and controls. We looked for associations between the severity criteria of SCA and delayed puberty through multivariate analysis.

RESULTS

Delayed puberty was reported in 27.3% of girls and 10% of boys with SCA. The median age of menarche was delayed by 2 years compared to controls. SCA patients had a low lean body mass compared to controls (p = 0.03). Anti-mullerian hormone levels were significantly higher in boys with SCA than those of controls (45.9 ng/mL vs. 17.65 ng/mL; p = 0.018). A history of severe infection, acute chest syndrome, and low hemoglobin level was associated with delayed sexual maturation in children with SCA.

CONCLUSION

Our study revealed delayed puberty in children with SCA. Moreover, puberty is affected by the severity of the disease. This highlights the importance of regular monitoring of puberty during the follow-up of these children.

Estrogen Receptor α Inactivation in 2 Sisters: Different Phenotypic Severities for the Same Pathogenic Variant

CONTEXT

Estrogens play an essential role in reproduction. Their action is mediated by nuclear α and β receptors (ER) and by membrane receptors. Only 3 females and 2 males, from 3 families, with a loss of ERα function have been reported to date.

OBJECTIVE

We describe here a new family, in which 2 sisters display endocrine and ovarian defects of different severities despite carrying the same homozygous rare variant of ESR1.

METHODS

A 36-year-old woman from a consanguineous Jordanian family presented with primary amenorrhea and no breast development, with high plasma levels of 17β-estradiol (E2), follicle-stimulating hormone and luteinizing hormone, and enlarged multifollicular ovaries, strongly suggesting estrogen resistance. Her 18-year-old sister did not enter puberty and had moderately high levels of E2, high plasma gonadotropin levels, and normal ovaries.

RESULTS

Genetic analysis identified a homozygous variant of ESR1 leading to the replacement of a highly conserved glutamic acid with a valine (ERα-E385V). The transient expression of ERα-E385V in HEK293A and MDA-MB231 cells revealed highly impaired ERE-dependent transcriptional activation by E2. The analysis of the KISS1 promoter activity revealed that the E385V substitution induced a ligand independent activation of ERα. Immunofluorescence analysis showed that less ERα-E385V than ERα-WT was translocated into the nucleus in the presence of E2.

CONCLUSION

These 2 new cases are remarkable given the difference in the severity of their ovarian and hormonal phenotypes. This phenotypic discrepancy may be due to a mechanism partially compensating for the ERα loss of function.

Glucocorticoid induced adrenal insufficiency in children: Morning cortisol values to avoid LDSST

OBJECTIVES

Glucocorticoid-induced adrenal insufficiency (GI-AI) is a common side effect of glucocorticoid therapy. However, its diagnosis currently relies on the realization of a Low Dose Short Synacthen Test (LD-SST) that requires an outpatient hospital and several blood samples. Our goal was to evaluate whether morning cortisol values could predict the response to LD-SST, in children, to avoid useless dynamic tests and facilitate diagnosis of glucocorticoid induced adrenal insufficiency.

STUDY DESIGN

We recorded data of 91 pediatric patients who underwent a LD-SST in our center between 2016 and 2020 in a retrospective observational study. We selected LD-SST realized following administration of supra-physiologic doses of glucocorticoids during more than 3 weeks and performed at least four weeks after treatment was stopped. Adrenal deficiency was defined as a plasma cortisol concentration inferior to 500 nmol/l at LD-SST.

RESULTS

Glucocorticoid-induced adrenal insufficiency was diagnosed in 60% of our cohort. Morning cortisol values were predictive of the response to the LD-SST (AUC ROC 0.78). A plasma cortisol concentration of less than 144 nmol/l predicted glucocorticoid induced adrenal insufficiency with a specificity of 94% and a value over 317 nmol/l predicted recovery of the HPA axis with a sensitivity of 95%. We did not find any other predictive factor for glucocorticoid-induced adrenal insufficiency.

CONCLUSIONS

Morning cortisol values can safely assess recovery of the HPA axis in children treated chronically with glucocorticoids. Using these thresholds, more than 50% of LD-SST could be avoided in children.

One Year of GH Treatment for Growth Failure in Children With Anorexia Nervosa: A Randomized Placebo-Controlled Trial

CONTEXT

Children with anorexia nervosa (AN) are at risk of adult height deficit due to prolonged low height velocity (HV).

OBJECTIVE

To investigate the effects of human growth hormone (GH) injections on HV in children with AN and severe growth impairment.

DESIGN AND PARTICIPANTS

In this prospective, randomized, double-blind, single-center, proof-of-concept trial, children with AN and low HV (≤2 cm/year) for at least 18 months, and a bone age ≤12 years for girls and ≤14 years for boys, were randomized to receive daily subcutaneous injections of human GH (0.050 mg/kg/day) or placebo for 12 months.

MAIN OUTCOME MEASURES

Change in HV after 12 months.

RESULTS

In total, 8 patients were assigned to the GH group and 6 to the placebo group. Patients had a median (25th-75th percentile) HV of 1.0 (0.5;1.5) cm/year. The effect of GH treatment increased strongly after 6 months, with a height gain after 12 months of 9.65 (8.0;11.6) cm for the GH group vs 3.85 (1.7;7.3) cm for the placebo group, with an absolute median (2.5th-97.5th percentile) difference between the groups of 5.8 (-1.85;9.68) cm after bootstrapping. The percentage of patients with a HV > 5 cm/year during the study period was higher in the GH group than in the placebo group (100% vs 50%, P = 0.05). Adverse events occurred in similar numbers in the 2 groups, were mild or nonfatal, and did not lead to treatment being stopped.

CONCLUSION

GH administration to improve HV is a potentially valid option for increasing HV in children with AN and prolonged severe growth failure.

Prevalence and course of thyroid dysfunction in neonates at high risk of Graves' disease or with non-autoimmune hyperthyroidism

OBJECTIVE

Neonatal hyperthyroidism may be caused by a permanent non-autoimmune genetic disorder or, more frequently, by maternally transmitted high serum TRAb levels. Variable thyroid dysfunction may be observed in this second context. We aimed to evaluate the prevalence of neonatal non-autoimmune hyperthyroidism and of the different types of thyroid function in neonates with a high risk of hyperthyroidism due to maternal Graves' disease (GD).

DESIGN AND METHODS

This observational cohort study included all neonates identified in the database of a single academic pediatric care center, over a period of 13 years, as having non-autoimmune hyperthyroidism or an autoimmune disorder with high TRAb levels (above 6 IU/L) transmitted by their mothers. Patients were classified as having neonatal hyperthyroidism, hypothyroidism, or euthyroidism with a permanent or transient disorder.

RESULTS

Two of the 34 consecutive neonates selected (6%) had permanent non-autoimmune hyperthyroidism due to germline (n = 1) or somatic (n = 1) mutations of the TSH receptor gene. The patients with high serum TRAb levels at birth had transient hyperthyroidism (n = 23), hypothyroidism (primary n = 2, central n = 3) or persistent euthyroidism (n = 4).

CONCLUSION

These original findings highlight the need for careful and appropriate monitoring of thyroid function in the long term, not only for the rare patients with non-autoimmune neonatal hyperthyroidism, but also for repeat monitoring during the first month of life in neonates with maternally transmitted high TRAb levels, to ensure the early identification of thyrotoxicosis in more than two thirds of cases and to detect primary or central hypothyroidism, thereby potentially decreasing associated morbidity.

Impact of the underlying etiology of growth hormone deficiency on serum IGF-I SDS levels during GH treatment in children

CONTEXT

Regular monitoring of serum IGF-I levels during growth hormone (GH) therapy has been recommended, for assessing treatment compliance and safety.

OBJECTIVE

To investigate serum IGF-I SDS levels during GH treatment in children with GH deficiency, and to identify potential determinants of these levels.

DESIGN, PATIENTS AND METHODS

This observational cohort study included all patients (n = 308) with childhood-onset non-acquired or acquired GH deficiency (GHD) included in the database of a single academic pediatric care center over a period of 10 years for whom at least one serum IGF-I SDS determination during GH treatment was available. These determinations had to have been carried out centrally, with the same immunoradiometric assay. Serum IGF-I SDS levels were determined as a function of sex, age and pubertal stage, according to our published normative data.

RESULTS

Over a median of 4.0 (2-5.8) years of GH treatment per patient, 995 serum IGF-I SDS determinations were recorded. In addition to BMI SDS, height SDS and GH dose (P < 0.01), etiological group (P < 0.01) had a significant effect on serum IGF-I SDS levels, with patients suffering from acquired GHD having higher serum IGF-I SDS levels than those with non-acquired GHD, whereas sex, age, pubertal stage, treatment duration, hormonal status (isolated GHD (IGHD) vs multiple pituitary hormone deficiency (MPHD)) and initial severity of GHD, had no effect.

CONCLUSIONS

These original findings have important clinical implications for long-term management and highlight the need for careful and appropriate monitoring of serum IGF-I SDS and GH dose, particularly in patients with acquired GHD, to prevent the unnecessary impact of potential comorbid conditions.

Efficacy and Safety of Continuous Subcutaneous Infusion of Recombinant Human Gonadotropins for Congenital Micropenis during Early Infancy

BACKGROUND

Early postnatal administration of gonadotropins to infants with congenital hypogonadotropic hypogonadism (CHH) can mimic minipuberty, thereby increasing penile growth. We assessed the effects of gonadotropin infusion on stretched penile length (SPL) and hormone levels in infants with congenital micropenis.

METHODS

Single-center study including 6 males with micropenis in case of isolated CHH (n = 4), panhypopituitarism (n = 1), and partial androgen insensitivity syndrome (PAIS; n = 1). Patients were evaluated at baseline, monthly and at the end of the study through a clinical examination (SPL, testicular position and size), serum hormone assays (testosterone, luteinizing hormone, follicle-stimulating hormone, inhibin B, anti-Müllerian hormone [AMH]), and ultrasound of penis/testes.

RESULTS

In CHH, significant increases occurred in serum testosterone (from undetectable level to 3.5 ± 4.06 ng/mL [12.15 ± 14.09 nmol/L]), SPL (from 13.8 ± 4.5 to 42.6 ± 5 mm; p < 0.0001), inhibin B (from 94.8 ± 74.9 to 469.4 ± 282.5 pg/mL, p = 0.04), and AMH (from 49.6 ± 30.6 to 142 ± 76.5 ng/mL, p = 0.03). Micropenis was corrected in all patients, except one. On treatment, in the patient with PAIS, SPL was increased from 13 to 38 mm.

CONCLUSIONS

Early gonadotropin infusion is a safe, well-tolerated and effective treatment. The effect in PAIS has not been reported previously. Long-term follow-up is needed to assess the impact, if any, on future fertility and reproduction.
.

Hyperhomocysteinaemia, methylenetetrahydrofolate reductase polymorphism and risk of coronary artery disease

Background: Hyperhomocysteinaemia is an independent, graded risk factor for coronary artery disease (CAD). The methylenetetrahydrofolate reductase (MTHFR) polymorphism is associated with hyperhomcysteinaemia and may therefore influence individual susceptibility to CAD. We have investigated this risk factor in a Tunisian Arab population.

Methods: Polymerase chain reaction-restriction fragment length polymorphism analysis was used to detect the C677T and A1298C variants of the MTHFR gene in 100 patients with CAD and 120 healthy controls. The severity of CAD was expressed as the number of affected vessels. Plasma total homocysteine (tHcy) concentration was determined using a direct chemiluminescence assay.

Results: MTHFR CC, CT and TT genotype frequencies in the CAD group were significantly different from those observed in the control group (49%, 35% and 16% versus 48.3%, 45.8% and 5.8%, respectively; P=0.031). However, MTHFR AA, AC and CC genotypes frequencies in the CAD group were not significantly different from the control group ( P = 0.568). Patients with CAD showed higher plasma tHcy concentrations than patients without CAD (15.86±8.63 μmol/L versus 11.90 ± 3.25 μmol/L, P<0.001). There was no association between the MTHFR polymorphisms and the number of stenosed vessels. Patients with the MTHFR TT genotype had higher plasma tHcy, serum creatinine, cholesterol and triglyceride concentrations than patients with the MTHFR CC genotype.

Conclusions: The C677T polymorphism of the MTHFR gene is associated with hyperhomocysteinaemia, lipid dysregulation and the presence of CAD in this Tunisian Arab population.

Prenatal diagnosis of Bartter syndrome: amniotic fluid aldosterone

OBJECTIVE

Bartter syndrome is a severe inherited tubulopathy characterized by postnatal salt wasting, severe polyuria, dehydration, failure to thrive and secondary hyperaldosteronism. Prenatally, the disease is usually discovered following the onset of severe polyhydramnios in the second trimester. We studied amniotic fluid aldosterone concentration in Bartter syndrome and in controls.

METHODS

Amniotic fluid aldosterone was assayed by radioimmunoassay. We undertook a retrospective case-control study based on 36 cases of prenatally suspected and postnatally confirmed Bartter syndrome (22 with identified mutations): and 72 gestational age matched controls presenting with polyhydramnios and 72 without polyhydramnios. Amniotic fluid aldosterone was compared between the three groups.

RESULTS

The median amniotic fluid aldosterone concentration in the Bartter syndrome group (90 pg/mL) was not different from that in the controls with polyhydramnios (90 pg/mL, P = 0.33) or without polyhydramnios (87 pg/mL, P = 0.41).

CONCLUSION

Amniotic fluid aldosterone assay cannot be used for prenatal diagnosis of Bartter syndrome. © 2015 John Wiley & Sons, Ltd.

Triiodothyronine-predominant Graves' disease in childhood: detection and therapeutic implications

OBJECTIVE

To assess in a pediatric population, the clinical characteristics and management of triiodothyronine-predominant Graves' disease (T3-P-GD), a rare condition well known in adults, but not previously described in children.

DESIGN

We conducted a university hospital-based observational study.

METHODS

All patients with GD followed for more than 1 year between 2003 and 2013 (n=60) were included. T3-P-GD (group I) was defined as high free T3 (fT3) concentration (>8.0 pmol/l) associated with a normal free thyroxine (fT4) concentration and undetectable TSH more than 1 month after the initiation of antithyroid drug (ATD) treatment. Group II contained patients with classical GD without T3-P-GD.

RESULTS

Eight (13%) of the patients were found to have T3-P-GD, a median of 6.3 (3.0-10.5) months after initial diagnosis (n=4) or 2.8 (2.0-11.9) months after the first relapse after treatment discontinuation (n=4). At GD diagnosis, group I patients were more likely to be younger (6.8 (4.3-11.0) vs 10.7 (7.2-13.7) years) and had more severe disease than group II patients, with higher serum TSH receptor autoantibodies (TRAb) levels: 40 (31-69) vs 17 (8-25) IU/l, P<0.04, and with slightly higher serum fT4 (92 (64-99) vs 63 (44-83) pmol/l) and fT3 (31 (30-46) vs 25 (17-31) pmol/l) concentrations. During the 3 years following T3-P-GD diagnosis, a double dose of ATD was required and median serum fT4:fT3 ratio remained lower in group I than in group II.

CONCLUSION

Severe hyperthyroidism, with particularly high TRAb concentrations at diagnosis, may facilitate the identification of patients requiring regular serum fT3 determinations and potentially needing higher doses of ATD dosage during follow-up.

Haploinsufficiency of Dmxl2, encoding a synaptic protein, causes infertility associated with a loss of GnRH neurons in mouse

Characterization of the genetic defects causing gonadotropic deficiency has made a major contribution to elucidation of the fundamental role of Kisspeptins and Neurokinin B in puberty onset and reproduction. The absence of puberty may also reveal neurodevelopmental disorders caused by molecular defects in various cellular pathways. Investigations of these neurodevelopmental disorders may provide information about the neuronal processes controlling puberty onset and reproductive capacity. We describe here a new syndrome observed in three brothers, which involves gonadotropic axis deficiency, central hypothyroidism, peripheral demyelinating sensorimotor polyneuropathy, mental retardation, and profound hypoglycemia, progressing to nonautoimmune insulin-dependent diabetes mellitus. High-throughput sequencing revealed a homozygous in-frame deletion of 15 nucleotides in DMXL2 in all three affected patients. This homozygous deletion was associated with lower DMXL2 mRNA levels in the blood lymphocytes of the patients. DMXL2 encodes the synaptic protein rabconnectin-3α, which has been identified as a putative scaffold protein for Rab3-GAP and Rab3-GEP, two regulators of the GTPase Rab3a. We found that rabconnectin-3α was expressed in exocytosis vesicles in gonadotropin-releasing hormone (GnRH) axonal extremities in the median eminence of the hypothalamus. It was also specifically expressed in cells expressing luteinizing hormone (LH) and follicle-stimulating hormone (FSH) within the pituitary. The conditional heterozygous deletion of Dmxl2 from mouse neurons delayed puberty and resulted in very low fertility. This reproductive phenotype was associated with a lower number of GnRH neurons in the hypothalamus of adult mice. Finally, Dmxl2 knockdown in an insulin-secreting cell line showed that rabconnectin-3α controlled the constitutive and glucose-induced secretion of insulin. In conclusion, this study shows that low levels of DMXL2 expression cause a complex neurological phenotype, with abnormal glucose metabolism and gonadotropic axis deficiency due to a loss of GnRH neurons. Our findings identify rabconectin-3α as a key controller of neuronal and endocrine homeostatic processes.

SGA children with moderate catch-up growth are showing the impaired insulin secretion at the age of 4

Background

Being born small for gestational age (SGA) is a risk factor for later development of type 2 diabetes. The development of glucose tolerance disorders in adults involves insulin resistance and impaired insulin secretion.

Objective

To evaluate insulin secretion and insulin sensitivity in a 4-yr old cohort of SGA.

Methods

85 children were prospectively followed from mid-gestation to 4 years of age. Fetal growth velocity (FGV) was measured using ultrasound measurements. Body composition and hormonal profile were measured at birth, 1 and 4 years.

Results

23 SGA babies had lower birth weight compared to 62 AGA (−1.9±0.3 vs. −0.6±0.8 z-score; p<0.0001) and they were thinner at birth (ponderal index 24.8±1.8 vs. 26.3±3.1 kg/m3; p = 0.01 and fat mass 11±2.6 vs. 12.9±3.1%; p = 0.01). No significant differences in other measured metabolic and hormonal parameters were observed between two groups at birth. SGA infants experienced an early catch-up growth in weight (mean gain of 1.1±0.6 SD) during the first year of life. At 4 years, SGA children remain lighter than AGA, but with weight z-score in the normal range (−0.1±1.3 vs. 0.5±1.3 z-score; p = 0.05). No excess of fat mass was observed (19±4.8 vs. 19.7±4.1%; p = 0.45). 120-min plasma glucose was significantly higher (6.2±1.1 vs. 5.6±0.9 mmol/l; p = 0.006) and insulinogenic index was significantly lower (0.28±0.15 vs. 0.40±2.4; p = 0.02) in the SGA group at 4-yrs of life contrasting with a preserved insulin sensitivity (QUICKI 0.47±0.09 vs. 0.43±0.05; p = 0.06).

Conclusion

SGA children with compensatory catch-up growth in first year of life show mild disturbances of glucose tolerance associated to a lower insulinogenic index at 4-yrs of age suggesting impairment of β-cell function.

A simple and fast non-radioactive bridging immunoassay for insulin autoantibodies

Type 1 diabetes (T1D) is an autoimmune disease which results from the destruction of pancreatic beta cells. Autoantibodies directed against islet antigens are valuable diagnostic tools. Insulin autoantibodies (IAAs) are usually the first to appear and also the most difficult to detect amongst the four major islet autoantibodies. A non-radioactive IAA bridging ELISA was developed to this end. In this assay, one site of the IAAs from serum samples is bound to a hapten-labeled insulin (GC300-insulin), which is subsequently captured on anti-GC300 antibody-coated 96-well plates. The other site of the IAAs is bound to biotinylated insulin, allowing the complex to be detected by an enzyme-streptavidin conjugate. In the present study, 50 serum samples from patients with newly diagnosed T1D and 100 control sera from non-diabetic individuals were analyzed with our new assay and the results were correlated with an IAA radioimmunoassay (RIA). Using IAA bridging ELISA, IAAs were detected in 32 out of 50 T1D children, whereas with IAA RIA, 41 out of 50 children with newly diagnosed T1D were scored as positive. In conclusion, the IAA bridging ELISA could serve as an attractive approach for rapid and automated detection of IAAs in T1D patients for diagnostic purposes.

Effects of recombinant human growth hormone for 1 year on body composition and muscle strength in children on long-term steroid therapy: randomized controlled, delayed-start study

CONTEXT

Recombinant human GH (rhGH) improves growth and body composition in glucocorticoid-treated children. Its effects on muscle strength are poorly evaluated.

OBJECTIVES

Our objective was to evaluate rhGH effects on muscle strength in children receiving long-term glucocorticoid therapy; effects on height SD score (SDS) and body composition were assessed also.

DESIGN AND SETTING

A randomized, controlled, delayed-start study of rhGH for 12 months was started after randomization (baseline) or 6 months later (M6).

PATIENTS

Patients included 30 children with various diagnoses.

INTERVENTION

rhGH was administered at 0.065 mg/kg/d for 6 months and then in the dosage maintaining serum IGF-I levels below +2 SDS for chronological age.

MAIN OUTCOME MEASURES

The primary criterion was the between-group difference in composite index of muscle strength (CIMS) change at M6. Secondary criteria included between-group differences in CIMS SDS(height), lean mass (LM), thigh muscle area (MA), and height SDS changes at M6; these parameters were also assessed in the overall population after 1 year of rhGH therapy.

RESULTS

At M6, rhGH therapy did not significantly affect changes in CIMS or CIMS SDS(height) (+17.6% vs +7.5% and +0.14 ± 0.38 vs +0.11 ± 0.62, respectively); the rhGH-treated group had significantly larger changes in height SDS (+0.2 [0.3] vs -0.2 [0.3]; P = 0.003), LM (+7.3% [+3.7%; +21.6%] vs 0% [-4.7%; +3.2%]; P = 0.002), and MA (+8.8% [+5%; +15.6%] vs. -0.6% [-6.3%; +7.7%]; P = 0.01) compared with the untreated group. After 1 year of rhGH, height SDS, LM, and MA increased significantly, CIMS increased by 24.7% (+5.8%; +34.2%), and CIMS SDS(height) remained within the normal range.

CONCLUSIONS

rhGH increased height, LM, and MA. However, muscle strength did not improve significantly.

Innate small babies are metabolically healthy children

BACKGROUND

Being born small for gestational age (SGA) is regarded as a risk factor for later metabolic complications. The SGA is defined as a birth weight below -2 SD of the distribution for sex and gestational age. However, the definition of SGA does not distinguish between those born after fetal growth restriction and innate SGA (iSGA).

OBJECTIVE

Our objective was to test whether innate SGA infants show any metabolic complications at the age of 2 yr in comparison with infants born appropriate for gestational age (AGA).

METHODS

Fifty-eight infants with family SGA risk factors (SGA in a previous pregnancy or among parents, maternal height less than -2 sd for adult height in French women, and small fetal size at second-trimester ultrasound examination) were prospectively followed from midgestation to 2 yr of age. Fetal growth velocity was measured from ultrasound measurements. Body composition and hormonal profile were measured at birth and 1 and 2 yr.

RESULTS

Fetal growth velocity was not significantly different between iSGA and AGA (-0.17 ± 0.2 vs. -0.17 ± 0.3 percentiles/d of gestation; P = 0.96). iSGA infants were significantly lighter at birth (-1.7 ± 0.45 vs. 0.46 ± 0.77 SD; P < 0.0001) and at 4 months of age (-0.85 ± 0.88 vs. 0.29 ± 1 SD; P < 0.0001), and they remain so over follow-up (-0.73 ± 1.08 vs. 0.2 ± 1.02 SD; P = 0.0014 at 2 yr). Height z-scores and percent fat time courses followed a similar pattern. No differences in any of the metabolic and hormonal parameters were observed between iSGA and AGA up to 2 yr (insulin at birth, 5.1 ± 6.8 vs. 5.2 ± 4.6 mIU/liter, P = 0.2; at 2 yr, 2 ± 1.6 vs. 2 ± 1.5 mIU/liter, P = 0.66).

CONCLUSION

Infants born iSGA do not experience severe fetal growth restriction and do not show any evidence of metabolic risk either at birth or in the first 2 yr of life.

Negative fetal FSH/LH regulation in late pregnancy is associated with declined kisspeptin/KISS1R expression in the tuberal hypothalamus

OBJECTIVE

Kisspeptins were recently identified as hypothalamic neuropeptides that control GnRH release at pubertal onset and in adults via the activation of KISS-1 receptor (KISS1R). Here, we have tested whether the fetal activation of the gonadotropic axis is related to the hypothalamic expression of kisspeptins and KISS1R.

DESIGN AND METHODS

LH and FSH levels were measured in fetal blood from the 15th week of gestation (WG) to birth. Immunohistochemistry was performed on the hypothalamus and pituitary at different developmental stages.

RESULTS

Immunostaining for kisspeptins and KISS1R appeared for both proteins in the hypothalamus as early as 15 WG and subsequently increased until 30-31 WG. In the meantime, serum LH and FSH levels decreased from postmenopausal levels in females or adult levels in males to very low levels. At full term, kisspeptin and KISS1R staining was still observed in the paraventricular, supraoptic, and ventromedial hypothalamic nuclei but not in the arcuate nucleus or median eminence. Hypothalamic GnRH staining was observed at 15 WG and did not vary after the first trimester. In an arhinencephalic fetus of 23 WG, very few GnRH neurons were observed in the hypothalamus, but serum FSH and LH levels were postmenopausal.

CONCLUSION

Serum LH and FSH levels are independent from GnRH and kisspeptins at midgestation, and then GnRH progressively controls LH and FSH release. A shift from kisspeptin-independent to kisspeptin-dependent GnRH-induced LH and FSH release seems to occur after 30-31 WG. In addition to their function in adults, kisspeptins are also the master regulators of the gonadotropic axis activation in the fetus.

Serum Concentrations of Insulin-like Growth Factor (IGF)-1 and IGF Binding Protein-3 (IGFBP-3), IGF-1/IGFBP-3 Ratio, and Markers of Bone Turnover: Reference Values for French Children and Adolescents and z-Score Comparability with Other References

BACKGROUND

A reference model for converting serum growth factor and bone metabolism markers into an SD score (SDS) is required for clinical practice. We aimed to establish reference values of serum insulin-like growth factor-1 (IGF-1) and IGF binding protein 3 (IGFBP-3) concentrations and bone metabolism markers in French children, to generate a model for converting values into SDS for age, sex, and pubertal stage.

METHODS

We carried out a cross-sectional study of 1119 healthy white children ages 6–20 years. We assessed concentrations of serum IGF-1, IGFBP-3, carboxyterminal telopeptide α1 chain of type I collagen (CrossLaps), and bone alkaline phosphatase concentrations and height, weight, and pubertal stage, and used semiparametric regression to develop a model.

RESULTS

A single regression model to calculate the SDSs with an online calculator was provided. A positive relationship was found between SDS for serum IGF-1 and IGFBP-3, IGF/IGFBP-3 mol/L ratio, and anthropometric parameters (P &lt; 0.0001), with slightly greater effects observed for height than for body mass index (BMI). There was a negative relationship between serum CrossLaps concentration and BMI, and a positive relationship between serum CrossLaps concentration and height. A comparison of serum IGF-1 reference databases for children showed marked variation as a function of age and pubertal group; smooth changes with age and puberty were observed only in our model.

CONCLUSIONS

This new model for the assessment of SDS reference values specific for age, sex, and pubertal stage may help to increase the diagnostic power of these parameters for the assessment of growth and bone metabolism disorders. This study also provides information about the physiological role of height and BMI for the interpretation of these parameters.

Evaluation of an ELISA assay for total proinsulin and establishment of reference values during an oral glucose tolerance test in a healthy population

OBJECTIVES

Assessment of the analytical performance of the Total Proinsulin ELISA Kit (Millipore) and determination of reference values.

DESIGN AND METHODS

Imprecision, specificity, antibodies interference and reference values in normoglycaemic non-obese adults were determined.

RESULTS

The inter-assay CV is <6.9%, the limits of detection and quantification are 0.2 and 0.6 pmol/L. Molar cross-reactivity of split proinsulins varies from 103 to 92.5%. The interference of anti-(pro)insulin antibodies can be eliminated with the use of polyethylene glycol. The reference values are 2.7-14.2 pmol/L at fasting, 8.5-56.5 pmol/L at T30 min and 11.9-70.5 pmol/L at T120 min during an OGTT.

CONCLUSION

The reference values established for this kit, which showed good analytical performances, allow for a better assessment of pathologies associated with increased proinsulinaemia.

Plasminogen activator inhibitor type-1 is an independent marker of metabolic disorders in young adults born small for gestational age

BACKGROUND

Metabolic syndrome (MS) has been associated with being born small for gestational age (SGA). In epidemiological studies plasminogen activator inhibitor type-1 (PAI-1) levels have been associated with MS. Few studies have examined this association in subjects born SGA.

PATIENTS AND METHODS

Five hundred and fifty-seven SGA adults (birth weight < 10th percentile) were compared with 671 subjects with a birth weight between the 25th and 75th percentiles (control group). MS was defined using the World Health Organization (WHO) definition. Active PAI-1 was measured on citrated plasma with bio-immunoassay.

RESULTS

MS was more prevalent in the SGA group (8.7%) than in the control group (5.5%; P = 0.03). In both groups, PAI-1 concentrations were significantly correlated with waist circumference, plasma triglycerides, homeostatic model assessment-insulin resistance (HOMA-IR) and associated with male sex and MS. PAI-1 concentrations were significantly increased in the SGA group (12.2 ± 21.2 vs. 10.0 ± 13.5 IU mL⁻¹, P = 0.03) and this remained after adjustment of metabolic variables (P = 0.009). PAI-1 concentrations above 4.9 IU mL⁻¹ (= median of PAI-1 concentration in the control group) were present in 94% of the subjects with MS. Moreover, the adjusted odds ratio (OR) for having elevated PAI-1 was 1.48 (1.08; 1.95) in the SGA group in comparison with the control group (P = 0.005).

CONCLUSIONS

 PAI-1 plasma concentrations were significantly increased in SGA subjects independently of MS. These data suggest that elevation of PAI-1 concentrations might be an indication of an abnormal secretion at the level of the adipose tissue, endothelial cells or liver and implicated in metabolic disorders reported in SGA subjects.

Moderate deterioration in glucose tolerance during high-dose growth hormone therapy in glucocorticoid-treated patients with juvenile idiopathic arthritis

OBJECTIVES

To describe glucose metabolism changes during growth hormone (GH) treatment in juvenile idiopathic arthritis (JIA).

STUDY DESIGN

Observational study in 58 children on glucocorticoid therapy (GC) for JIA, of whom 28 received late GH therapy (7.3 +/- 3.4 years into GC), 15 early GH therapy (1.2 +/- 0.1 years into GC), and 15 no GH therapy. The GH dose was 0.46 mg/kg/week. Oral glucose tolerance testing with insulin and glycosylated hemoglobin assays were performed yearly. Nonparametric tests were used to compare groups after 3 years and regression analyses to estimate factors predicting glucose AUC and HOMA-IR at baseline and after 3 years.

RESULTS

GH combined with GC was associated with an increase in mean fasting insulinemia. Late GH therapy patients exhibited significant increases over time in mean fasting glycemia (p = 0.01), mean 2-hour postglucose load glycemia (p < 0.05), mean AUC for glucose (p < 0.05), and mean HOMA-IR (p < 0.05). Impaired glucose tolerance was found in 16/43 GH-treated patients (37%) and transient diabetes in 2 (5%) patients.

CONCLUSIONS

GH treatment in JIA children decreased insulin sensitivity but had only modest effects on glucose tolerance. Close monitoring by oral glucose tolerance testing is crucial before and during GH treatment, particularly during puberty and relapses.

Resistance to leptin-replacement therapy in Berardinelli-Seip congenital lipodystrophy: an immunological origin

CONTEXT

Recently, in a 4-month proof-of-concept trial, beneficial metabolic effects were reported in non-diabetic children with Berardinelli-Seip congenital lipodystrophy (BSCL); this information prompted us to hypothesize that long-term leptin-replacement therapy might improve or reverse the early complications of the disease in these patients.

PATIENTS AND METHODS

A 28-month trial was implemented in eight patients. Efficacy assessment was based on a decrease in serum triglyceride concentrations, and/or a decrease in liver volume and/or an increase in insulin sensitivity of at least 30% respectively. The response was defined as follows: total (3/3 positive criteria), partial (1 or 2/3), or negative (0/3). Anti-leptin antibodies were measured with a radiobinding assay, and a neutralizing effect was assessed in primary cultures of embryonic neurons incubated with an apoptotic agent (N-methyl-D-aspartate) and the patient serum, with or without leptin.

RESULTS

A negative or partial response to treatment was observed in five of eight patients even when leptin dosages were increased. A displaceable leptin binding was detectable in all patients after 2 months of treatment. At 28 months, binding was higher in the patients with a negative response than in the total responders, and it paralleled both the increase in leptin dosage and serum leptin concentrations. Co-incubation of embryonic neurons with serum from two patients with a negative response inhibited the neuroprotective effect of leptin.

CONCLUSION

Under leptin therapy, patients with BSCL may develop a resistance to leptin, which could be partly of immunological origin, blunting the previously reported beneficial effects.

Independent effects of weight gain and fetal programming on metabolic complications in adults born small for gestational age

AIMS/HYPOTHESIS

Insulin resistance (IR) and the metabolic syndrome (MS) have been reported in adults as a consequence of being born small for gestational age (SGA). The process seems to be initiated early in life; however, little is known about the progression of MS and IR in young adults. We hypothesised that being born SGA would promote a greater progression over time of IR and MS, reflecting not only the gain in weight and fat mass but also the extension of the fetal programming process.

METHODS

Participants were selected from a community-based cohort and born full-term either SGA (birthweight <10th percentile) or appropriate for gestational age (25th < birthweight < 75th percentile). A total of 1,308 individuals were prospectively followed between the ages of 22 and 30 years.

RESULTS

At both ages, individuals born SGA were more insulin-resistant and showed a significantly higher prevalence of MS. Over the 8 year follow-up, the risk of developing MS was twofold higher in those SGA, after adjustment for gain in BMI, whereas the progression of IR was not significantly affected by the birth status.

CONCLUSIONS/INTERPRETATION

Our data suggest that metabolic disorders in SGA individuals are amplified by the weight gain with time when adults, both probably resulting from fetal programming. Moreover, the modest increase in IR contrasts with the constant and much higher prevalence of MS.

Pituitary-thyroid feedback in a patient with a sporadic activating thyrotropin (TSH) receptor mutation: implication that thyroid-secreted factors other than thyroid hormones contribute to serum TSH levels

CONTEXT

Constitutive mutations of the TSH receptor gene are a rare cause of severe congenital hyperthyroidism. Persistent TSH suppression has been described in euthyroid Graves' disease patients treated with antithyroid drugs. An ultrashort negative feedback loop affecting TSH secretion by activating the pituitary TSH receptor with TSH receptor autoantibodies has been suggested as a possible mechanism of TSH suppression in these patients.

OBJECTIVE AND DESIGN

The aim of the study was to determine whether TSH suppression also occurs in euthyroid treated patients with non-autoimmune hyperthyroidism. We investigated the outcome of pituitary-thyroid feedback in a patient carrying an activating mutation of the TSH-R gene in an observational prospective study. Repeated clinical investigations from birth until the age of 14 yr are presented for the patient on drug treatment and after radical treatment.

RESULTS

TSH was consistently undetectable or present at very low concentrations in the serum for several years, although FT(4) and FT(3) concentrations remained mostly in the normal range. Moreover, serum TSH concentrations increased only slightly when serum FT(4) concentrations fell below normal levels. During drug treatment, serum TSH concentrations expressed as a function of serum FT(4) and FT(3) concentrations were significantly lower than those for control or congenital hypothyroid populations. By contrast, after radical treatment, serum TSH levels increased, reaching the normal range, and low serum FT(4) and FT(3) concentrations were associated with appropriate increases in serum TSH concentrations.

CONCLUSION

These data provide insight into the regulation of serum TSH concentrations and suggest an alternative mechanism, in addition to serum thyroid hormone levels, for adjusting TSH secretion.

Medullary thyroid carcinoma identified within the first year of life in children with hereditary multiple endocrine neoplasia type 2A (codon 634) and 2B

CONTEXT

Early prophylactic thyroidectomy in patients with multiple endocrine neoplasia (MEN) type 2 offers the best chance for a normal life expectancy.

OBJECTIVE

To analyze the results of thyroidectomy performed during the first year of life in six patients with MEN 2A (codon 634) or MEN 2B (codon 918) syndrome.

DESIGN AND SETTING

A university hospital-based prospective study from 2001 to 2008.

SUBJECTS AND METHODS

Six family members affected either by MEN 2A (n=3) or MEN 2B (n=3) syndrome were identified through neonatal genetic screening.

RESULTS

Total thyroidectomy was performed at a median age of 0.8 year in the six patients, with central lymph node dissection in five. Bilateral millimetric medullary thyroid carcinoma (MTC) was found in all patients, with a unilateral lymph node micrometastasis in two of the three MEN 2B patients. Before thyroidectomy, MEN 2B patients had much higher basal serum calcitonin levels than those with MEN 2A and controls. After thyroidectomy, with a median follow-up of 3.3 years, the six patients had no evidence of persistent MTC.

CONCLUSION

Bilateral millimetric MTC may be present during the first year of life in these patients, with lymph node metastases also occurring in MEN 2B patients. These results support a total thyroidectomy at the age of about one year in MEN 2A (codon 634) children with an abnormal serum calcitonin level, and a total thyroidectomy with central neck dissection within the first weeks of life in MEN 2B patients.

Adaptive changes in neonatal hormonal and metabolic profiles induced by fetal growth restriction

CONTEXT

Birth weight (BW) is usually taken as a surrogate of fetal growth. However, BW per se is not relevant enough in assessing fetal growth restriction, which by itself may alter body composition, metabolic, and hormonal profiles at birth (irrespective of BW), reflecting the necessary adaptive changes in metabolism under poor fetal environment.

OBJECTIVE

Our objective was to measure body composition, hormonal, and metabolic parameters at birth in relation to both BW and fetal growth velocity.

METHODS

A total of 235 pregnancies at risk of low BW were included, and newborns were observed at birth. Fetal growth velocity was calculated as the change in customized percentiles of estimated fetal weight between 22 wk gestational age and birth. Newborns were ranked in descending order of fetal growth velocity and divided in three equal tertiles.

RESULTS

The lower fetal growth velocity tertile showed a severe fetal growth restriction (-52% +/- 21%) and was significantly associated with reduced lean and fat mass (P < 0.001 and 0.02, respectively). Insulin concentration was significantly related to fetal growth velocity (P = 0.006) and fat mass (P = 004) but not to BW (grams), whereas fetal growth velocity (P = 0.002) and BW (P < 0.001) but not fat mass had a significant effect on IGF-I concentration at birth.

CONCLUSION

Fetal growth restriction induces changes in body composition and metabolism suggestive of a higher insulin sensitivity independently from BW itself, reflecting adaptive changes to an adverse fetal nutritional environment.

Birth weight and long-term metabolic outcomes: does the definition of smallness matter?

OBJECTIVE

To establish the role of individual definition of smallness at birth in the association between birth weight and long-term metabolic outcomes.

METHODS

Lipid profile and oral glucose tolerance test were performed in young adults (22 years) born either small (SGA) or appropriate for gestational age (AGA). AGA/SGA were defined by both population-based and customized methods adjusting for individual maternal/pregnancy characteristics. 825 individuals were classified as AGA and 575 as SGA by both methods, 131 were SGA by the population-based method only (SGA(pop)) and 22 were SGA by the customized method only (SGA(cust)).

RESULTS

SGA(cust) subjects had higher total cholesterol and triglyceride levels and lower high-density lipoprotein cholesterol concentrations than SGA(pop) and AGA subjects, however, insignificantly when adjusted for age, gender and body mass index. The homeostasis model assessment for insulin resistance (HOMA-IR) index was higher in the SGA(cust) (p = 0.05) and SGA(pop) (p = 0.02) versus the AGA group. Controlling for the HOMA-IR index, the insulinogenic index was significantly lower in the SGA(cust) versus SGA(pop) (p = 0.001) and AGA (p = 0.003) groups. In SGA(cust) individuals, the HOMA-IR index was clearly shifted to higher, while the insulinogenic index to lower tertiles of AGA distribution; SGA(pop) subjects had the HOMA-IR and insulinogenic index predominantly in the highest tertiles.

CONCLUSIONS

Individualized birth weight standards allow to better identify subjects who failed to reach their genetic potential of intrauterine growth and are at higher risk of metabolic disturbances and impaired insulin secretion later in life.

Catch-up growth following fetal growth restriction promotes rapid restoration of fat mass but without metabolic consequences at one year of age

Background

Fetal growth restriction (FGR) followed by rapid weight gain during early life has been suggested to be the initial sequence promoting central adiposity and insulin resistance. However, the link between fetal and early postnatal growth and the associated anthropometric and metabolic changes have been poorly studied.

Methodology/Principal Findings

Over the first year of post-natal life, changes in body mass index, skinfold thickness and hormonal concentrations were prospectively monitored in 94 infants in whom the fetal growth velocity had previously been measured using a repeated standardized procedure of ultrasound fetal measurements. 45 infants, thinner at birth, had experienced previous FGR (FGR+) regardless of birth weight. Growth pattern in the first four months of life was characterized by greater change in BMI z-score in FGR+ (+1.26+/−1.2 vs +0.58 +/−1.17 SD in FGR−) resulting in the restoration of BMI and of fat mass to values similar to FGR−, independently of caloric intakes. Growth velocity after 4 months was similar and BMI z-score and fat mass remained similar at 12 months of age. At both time-points, fetal growth velocity was an independent predictor of fat mass in FGR+. At one year, fasting insulin levels were not different but leptin was significantly higher in the FGR+ (4.43+/−1.41 vs 2.63+/−1 ng/ml in FGR−).

Conclusion

Early catch-up growth is related to the fetal growth pattern itself, irrespective of birth weight, and is associated with higher insulin sensitivity and lower leptin levels after birth. Catch-up growth promotes the restoration of body size and fat stores without detrimental consequences at one year of age on body composition or metabolic profile. The higher leptin concentration at one year may reflect a positive energy balance in children who previously faced fetal growth restriction.

Lower insulin secretory response to glucose induced by artificial nutrition in children: prolonged and total parenteral nutrition

Long-term parenteral nutrition (TPN) in children is associated with sustained hyperinsulinemia due to a high nutriment infusion flow 12 h/24 h, with plausible lipotoxicity secondary to repeated lipid infusions and with changes in incretin hormone release. The aim of this study was to test whether long-term TPN can lead to an alteration in beta-cell function. Thirteen children (age 9.5 +/- 3.9 y) on total TPN without obvious alternation in glucose tolerance were included. beta-Cell function was quantified with an intravenous glucose tolerance test (IVGTT) and a graded glucose infusion. First phase insulin release (FPIR) was low in five patients. The same demonstrated a lower insulin release under graded glucose infusion, although plasma glucose reached values as high as 15 mM. These data emphasize that metabolic conditions induced by TPN can lead to lower insulin secretory response to glucose. Patients who remain dependent on TPN are at risk of developing glucose tolerance disorders.

The relationship between the GH/IGF-I axis and serum markers of bone turnover metabolism in healthy children

CONTEXT

There is evidence to suggest that IGF-I plays a role in regulating bone turnover.

OBJECTIVE

To evaluate the relationships between serum concentrations of IGF-I and IGF-binding protein-3 (IGFBP-3), and bone metabolism markers in healthy children.

DESIGN AND SETTING

Prospective cross-sectional study.

SUBJECTS AND METHODS

A cohort of 579 boys and 540 girls, all healthy Caucasian, were included in this study. Serum IGF-I and IGFBP-3 concentrations, bone alkaline phosphatase (BAP) and CrossLaps (markers of bone formation and bone resorption respectively) levels were evaluated as a function of age, gender, pubertal stage and body mass index.

RESULTS

Serum IGF-I SDS levels were positively correlated with BAP and CrossLaps SDS levels before and after puberty, and also with CrossLaps during puberty (weak correlation). Serum IGFBP-3 SDS levels were positively correlated with BAP and CrossLaps levels before, during (weak correlation) and after puberty (for BAP levels only).

CONCLUSIONS

This study demonstrated the independent association between serum IGF-I and IGFBP-3 concentrations with both serum bone formation and resorption markers in healthy children. Physiological differences before, during and after puberty in the association of serum IGF-I and IGFBP-3 levels with the serum bone metabolism markers were found. These differences may be related to differences in interactions between sex steroid hormones and the GH/IGF-I system, bone metabolism and growth during the pubertal transition. Improvements in our understanding of life course determinants of the IGF-I system and bone metabolism are required to shed further light on the role of the GH/IGF-I axis in bone remodelling.

Impact of fetal growth restriction on body composition and hormonal status at birth in infants of small and appropriate weight for gestational age

BACKGROUND

Fetal growth restriction (FGR) has been related to several health risks, which have been generally identified in small-for-gestational age (SGA) individuals.

OBJECTIVE

To evaluate the impact of FGR on body composition and hormonal status in infants born either small- or appropriate-for-gestational age (AGA).

METHODS

Fetal growth was assessed by ultrasound every 4 weeks from mid-gestation to birth in 248 high-risk pregnancies for SGA. Fetal growth velocity was calculated as change in the estimated fetal weight percentiles and FGR defined as its reduction by more than 20 percentiles from 22 gestational weeks to birth. Impact of FGR on body composition, cord insulin, IGF-I, IGF binding protein-3 (IGFBP-3), and cortisol concentrations was assessed in SGA and AGA newborns.

RESULTS

Growth-retarded AGA infants showed significantly reduced birth weight, ponderal index, percentage of fat mass, and bone mineral density when compared with AGA newborns with stable intrauterine growth. Cord IGF-I and IGFBP-3 concentrations were significantly decreased in growth-retarded infants in both SGA and AGA groups. Cord insulin concentration was significantly lower and cord cortisol significantly higher in AGA infants with FGR versus AGA newborns with stable intrauterine growth. After adjustment for gestational age and gender, birth weight was directly related to fetal growth velocity and cord IGF-I concentration. The variation in infant's adiposity was best explained by fetal growth velocity and cord insulin concentration.

CONCLUSIONS

FGR affects body composition and hormonal parameters in newborns with birth weight within the normal range, suggesting these individuals could be at similar metabolic risks as SGA. .

Subnormal serum insulin-like growth factor-I levels in young adults with childhood-onset nonacquired growth hormone (GH) deficiency who recover normal gh secretion may indicate less severe but persistent pituitary failure

CONTEXT

The unexpected observation of a normal GH peak in 22% of young adults with childhood-onset GH deficiency (GHD) and ectopic neurohypophysis has raised questions about the criteria defining GHD in young adults and whether patients with subsequent increases in GH secretion nonetheless have a subtle form of GHD.

OBJECTIVE

Our objective was to determine the characteristics of patients with childhood-onset nonacquired GHD who recover normal peak GH secretion when adult height has been achieved.

DESIGN AND SETTING

We conducted a university hospital-based observational follow-up study.

PARTICIPANTS

Sixty-two patients with ectopic neurohypophysis (n = 24), isolated hypoplastic anterior pituitary (n = 14), or normal hypothalamic pituitary area (n = 24) on magnetic resonance imaging (MRI) at the time of GHD diagnosis underwent reevaluation of the GH-IGF-I axis at a mean age of 16.8 +/- 1.6 yr.

MAIN OUTCOME MEASURES

Outcome measures included clinical and MRI findings and serum IGF-I and peak GH levels.

RESULTS

On retesting, peak GH exceeded 10 microg/liter in 31 patients (50%): six (20%) patients with ectopic neurohypophysis, 10 (32%) patients with initially isolated hypoplastic anterior pituitary, and 15 (48%) patients with normal MRI findings. Among these patients, serum IGF-I levels were significantly lower in patients with ectopic neurohypophysis than in those without structural abnormalities of the hypothalamic pituitary axis (n = 25), but patients without structural abnormalities also had significantly lower serum IGF-I levels than control subjects, after controlling for age, sex, and body mass index (mean serum IGF-I levels of 374 +/- 83 vs. 446 +/- 108 microg/liter; beta-coefficient = -72; P = 0.003).

CONCLUSIONS

The severity of the disease seems to have decreased over time in these patients, who may nonetheless present persistent pituitary failure. The natural history and clinical implications of these findings remain to be clarified. The possibility of a deterioration in the secretion of GH and other pituitary hormones later in life in a subset of these patients warrants the careful long-term follow-up of this population.

Metabolic correction induced by leptin replacement treatment in young children with Berardinelli-Seip congenital lipoatrophy

OBJECTIVE

Berardinelli-Seip syndrome is a rare congenital lipoatrophy with a severe prognosis and no efficient therapy. Children present with low leptin levels and severe metabolic complications (insulin resistance, elevated triglyceride levels, and hepatic steatosis). The objective of this study was to test safety and efficacy of recombinant-methionyl-human leptin replacement in children with Berardinelli-Seip syndrome before development of severe metabolic disease

METHODS

As part of an open trial, recombinant-methionyl-human leptin was given daily for 4 months to children who did not have diabetes and had Berardinelli-Seip congenital lipoatrophy and metabolic complications at a dosage that was meant to achieve physiologic levels. Six boys and 1 girl (age: 2.4-13.6 years), with a mean fasting insulin level of >15 mIU/L and hypertriglyceridemia, were included.

RESULTS

At the end of the recombinant-methionyl-human leptin treatment, a 63% reduction of fasting triglycerides level was achieved. A simultaneous 30% increase in insulin sensitivity was seen, and liver volume was reduced by 20.3%. More remarkable, values of insulin sensitivity and triglyceride level were in the reference range in 4 patients.

CONCLUSIONS

Leptin replacement is able to reverse metabolic complications in the majority of children with Berardinelli-Seip congenital lipoatrophy and with insulin resistance or dyslipidemia before the development of overt diabetes.

Reference intervals for follicle-stimulating hormone, luteinizing hormone and prolactin in children and young adults on the bioMérieux Mini-Vidas system

We measured serum follicle-stimulating hormone (FSH), luteinizing hormone (LH) and prolactin concentrations on a bioMérieux Mini Vidas system in a pediatric population ranging in age from 1 to 19 years. Reference intervals were established separately for females and males, with stratification by age group and by Tanner's pubertal stage. FSH values were higher in females than in males, and were lowest in both sexes of age class 2 (4–8 years), increasing thereafter to the upper limit for stage PIV (females) and stage PV (males). LH values showed a similar pattern of change: concentrations were lowest for class 1 (1–3 years) and class 2 (4–8 years), and highest for stage PII (females) and stage PV (males). No significant difference was observed according to gender. Prolactin values did not differ markedly according to gender or pubertal status.

Clin Chem Lab Med 2007;45:541–5.

Lower bone mineral content in children with type 1 diabetes mellitus is linked to female sex, low insulin-like growth factor type I levels, and high insulin requirement

CONTEXT

Studies on bone mineral characteristics in children with type 1 diabetes mellitus (T1DM) have generated conflicting results.

OBJECTIVE

Our objective was to investigate bone mineral characteristics in children with T1DM and to analyze their associations with bone metabolism and the IGF-I system.

DESIGN

We recruited a cohort of Caucasian patients with T1DM for at least 3 yr and healthy children between January 2003 and June 2004.

SETTING

This was a university hospital-based study.

PARTICIPANTS

A total of 127 patients and 319 controls aged 6 to 20 yr participated.

METHODS

Dual-energy x-ray absorptiometry was performed in patients and controls. Serum bone alkaline phosphatase, CrossLaps, IGF-I, and IGF-binding protein 3 levels were determined in patients with values analyzed using our normative data from 1150 healthy children.

RESULTS

After adjustment for age, sex, pubertal stage, and body mass index sd score, total body bone mineral content (BMC)/lean body mass was significantly lower in patients than in controls (P < 0.04). This difference was a result of the differences between the girls of the two groups. Girls with T1DM had significantly lower lumbar spine and total body BMC than control girls (P = 0.002), whereas no such difference was observed in boys. Serum bone alkaline phosphatase level was significantly lower in girls than in boys (P = 0.04). Low serum IGF-I levels and the administration of large amounts of insulin were found to have independent deleterious effects on BMC for children of all ages and both sexes, whereas disease duration and glycosylated hemoglobin levels did not.

CONCLUSIONS

A sex-related difference in the impairment of bone mineral characteristics was identified in children with T1DM. Longitudinal studies are required to investigate whether boys may gain slightly less bone mass during skeletal growth.

Serum adiponectin and leptin concentrations in HIV-infected children with fat redistribution syndrome

Human immunodeficiency virus (HIV)-related lipodystrophy is characterized by adipose tissue redistribution, dyslipidemia, and insulin resistance. We hypothesized that fat redistribution and metabolic abnormalities in HIV-infected children are related to alterations in endocrine function of adipose tissue. A multicenter study was conducted in 130 HIV-infected children. Lipodystrophy definition was based on the central to peripheral skinfold ratio. Fasting adiponectin, leptin, insulin concentrations, glycemia, and lipid profile were measured in all children. Fat redistribution syndrome was apparent in 32 children: 14 with atrophic (LPDA) and 18 with hypertrophic lipodystrophy (LPDH). Mean serum adiponectin levels were significantly decreased in LPDA and LPDH groups compared with the group with no lipodystrophy (LPD-). Fasting insulin concentration was significantly higher in LPDA and LPDH groups versus LPD-. Mean serum leptin concentration was significantly increased only in LPDH compared with LPDA and LPD- groups. Triglyceride levels were significantly increased and high-density lipoprotein (HDL)-cholesterol concentration decreased in the LPDA versus LPD- group. Controlling for puberty stage, gender, percentage of total fat mass, serum lipids, HIV treatment, and disease severity, adiponectin was significantly and inversely associated with central obesity and insulin/glucose ratio. Fat redistribution had no significant effect on leptin concentration, which was directly related to the percentage of body fat, female gender, and insulin/glucose ratio. In conclusion, HIV-infected children with symptoms of fat redistribution have decreased levels of adiponectin, associated with insulin resistance and dyslipidemia.

Inter-method variability in PTH measurement: implication for the care of CKD patients

The National Kidney Foundation/Kidney-Dialysis Outcome Quality Initiative guidelines recommend to maintain the serum intact parathyroid hormone (PTH) concentration between 150 and 300 ng/l in chronic kidney disease (CKD) stage 5 patients. As these limits were derived from studies that used the Allegro intact PTH assay, we aimed to evaluate whether they were applicable to other PTH assays. We compared the PTH concentrations measured with 15 commercial immunoassays in 47 serum pools from dialysis patients, using the Allegro intact PTH assay as the reference. We also evaluated the recovery of graded amounts of synthetic 1-84 and 7-84 PTH added separately to a serum pool. Although the assays were highly correlated, the concentrations differed from one assay to another. The median bias between the tested assays and the Allegro intact PTH assay ranged from -44.9 to 123.0%. When the PTH concentrations were 150 or 300 ng/l with the Allegro intact PTH assay, they ranged with other assays from 83 to 323 ng/l and from 160 to 638 ng/l, respectively. The tested assays recognized 7-84 PTH with various cross-reactivities, whereas a given amount of 1-84 PTH was recovered differently by these assays. We found important inter-method variability in PTH results owing to both antibody specificity and standardization reasons. The unacceptable consequence is that opposite therapeutic attitudes may be reached in a single patient depending on the PTH assay used. We propose to use assay-specific decision limits for CKD patients, or to apply a correcting factor to the PTH results obtained with a given assay.

Insulin resistance and the metabolic syndrome in obese French children

OBJECTIVE

To estimate the frequency of the metabolic syndrome (MS) and of the insulin resistance syndrome (IRS) in overweight or obese French children and to determine the risk factors.

DESIGN, PATIENTS AND METHODS

A total of 308 overweight and obese children [166 girls, 142 boys, aged 7-17 years; median body mass index (BMI) 4.7 standard deviation (SD) (Q1-Q3: 3.9-5.8) adjusted for age and sex] were included. The frequency of the MS was assessed with the National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) criteria and the frequency of the IRS with World Health Organization (WHO) criteria.

RESULTS

The overall frequency of MS and IRS was 15.9% and 42.5%, respectively. The most common component, after abdominal obesity (95.8%) and IR (71.8%), was elevated systolic blood pressure (28.6%). The frequency of glucose tolerance disorders was low (3.6%). The frequency of MS was independently influenced by homeostatic model assessment (HOMA) (P = 0.06) and waist-to-hip ratio (P = 0.09), whereas the frequency of IRS was influenced by adiposity (degree of obesity: P = 0.02; waist-to-hip ratio: P = 0.05), puberty (P = 0.05) and mother's BMI (P = 0.01). Ethnicity had no effect on either MS or IRS.

CONCLUSIONS

Metabolic complications and IR are frequent in overweight and obese children whereas the frequency of glucose tolerance disorders is very low. IRS is more prevalent than MS, indicating a major role of IR, which could precede the other metabolic complications in obese children. IRS is a relevant marker for the risk of type 2 diabetes (T2D) and cardiovascular complications in obese European children.

The INS VNTR locus does not associate with smallness for gestational age (SGA) but interacts with SGA to increase insulin resistance in young adults

CONTEXT

Both adverse intrauterine events and genetic background have been suggested to promote insulin resistance in subjects born small for gestational age (SGA). Among candidate genes that potentially influence both fetal growth and glucose metabolism is insulin. The potential effect of the insulin gene VNTR (INS) on birth weight has been controversial so far.

OBJECTIVE

The present association study aimed at testing for the contribution of the INS VNTR locus on birth weight and on the metabolic profile of young adults born SGA (mean age, 22 yr). Two groups of subjects were selected on birth data: SGA (birth weight < 10th percentile; n = 735), and appropriate for gestational age (AGA; birth weight between 25th and 75th percentiles; n = 886). All subjects were genotyped for rs689 A/T single nucleotide polymorphism, in complete linkage disequilibrium with the INS VNTR classes I and III, respectively.

RESULTS

Class I INS frequencies were similar in the two groups (70% in AGA; 72% in SGA; P = 0.42). There was significant effect on mean birth weight in neither SGA (P = 0.99) nor AGA (P = 0.18). Although the INS VNTR locus did not associate with anomalies of insulin resistance indices in the AGA group, in the SGA group, INS VNTR class III allele was associated with higher insulin resistance (quantitative insulin sensitivity check index = 0.38 vs. 0.39; P = 0.05). Furthermore, there was evidence of an interaction between the SGA/AGA status and INS VNTR locus on insulin resistance indices (P = 0.01) in a multivariate analysis.

CONCLUSION

The INS VNTR locus does not associate in a major way with SGA in the French population. However, our data support an interaction between severe fetal growth restriction and INS VNTR locus, which were associated with insulin resistance in young adults born SGA.

Characterization of insulin secretion and resistance in type 2 diabetes of adolescents

CONTEXT

Type 2 diabetes (T2D) in obese children is an emerging problem, including in Europe. Its presentation at diagnosis very often differs from that in adults.

OBJECTIVE

The objective of this study was to investigate the relative contributions of the two components of T2D, insulin resistance and insulin secretion, early in the history of the disease in adolescents.

PATIENTS AND METHODS

Six obese adolescents with T2D were included 2 months to 4.3 yr after diagnosis (five girls and one boy; median age, 15.4 yr; median body mass index, 4.4 sd). Peripheral and hepatic insulin sensitivity was evaluated with euglycemic hyperinsulinemic (40 mU/m(2).min) clamp. First-phase insulin release was evaluated after iv glucose stimulation. A graded iv glucose infusion and an arginine test were performed to measure insulin secretion.

RESULTS

All patients showed decreased peripheral glucose uptake to the same extent. Five patients showed hepatic insulin resistance. First-phase insulin release was very low in two patients. Three patients showed an exaggerated insulin response under graded glucose infusion and preserved secretion under arginine stimulation. Three other patients, with elevated fasting plasma glucose levels, demonstrated a very low insulin response under glucose stimulation and a low insulin response under arginine stimulation.

CONCLUSIONS

These data emphasize that together with marked insulin resistance, the failure of beta-cell function is a major component in the course of T2D in childhood.

Longitudinal evaluation and risk factors of lipodystrophy and associated metabolic changes in HIV-infected children

OBJECTIVE

To assess the rate of progression of lipodystrophy and the associated metabolic disturbances over a 2-year period in children and to assess risk factors associated with lipodystrophy and metabolic disturbances.

DESIGN

Multicenter 2-year prospective study with a standardized evaluation.

METHODS

One hundred thirty children (median age = 10 years, 64 boys and 66 girls) receiving antiretroviral therapy were recruited in 3 pediatric clinics. Lipodystrophy was defined based on 4 skinfold thickness measurements. Fasting lipids and glucose profile were measured in all children.

RESULTS

The proportion of children presenting with lipodystrophy was 24.6%. Nineteen percent of children had high-density lipoprotein values less than 1 mmol/L. Twenty-two percent and 15% of children had values greater than 2 standard deviations for age and gender for cholesterol and triglycerides, respectively. A total of 13.2% showed insulin resistance. A total of 42.7% showed at least 1 of these biologic disturbances. Prospective follow-up showed no progression at all over 2 years, except for a doubling of the number of children with insulin resistance. In multivariate analyses, ethnicity, previous severe clinical condition, duration of HIV infection, and nucleoside reverse transcriptase inhibitor treatment were significantly associated with lipodystrophy. Tanner stage V of puberty, severe clinical symptoms and protease inhibitor treatment were independently associated with the risk of metabolic disturbances.

CONCLUSIONS

Puberty seems to be the time when HIV-infected children taking potent antiretroviral therapy are more likely to develop lipodystrophy and metabolic complications, especially in children with a severe underlying HIV infection. Once developed, lipodystrophy and metabolic changes seem to be extremely stable with time.

Low serum adiponectin levels in subjects born small for gestational age: impact on insulin sensitivity

OBJECTIVE

Increasing evidence point to the role of the adipose tissue on the insulin resistance associated with reduced fetal growth. Since adiponectin, exclusively produced by the adipose tissue, exerts an important insulin-sensitizing activity, it appears critical to investigate the effect of being born small for gestational age (SGA) on adiponectin production in adulthood and its relationship with insulin sensitivity.

SUBJECTS AND METHODS

Serum adiponectin concentrations were measured in 486 young adults born SGA, precisely selected on birth data, who were compared to 573 age-matched subjects born appropriate for gestational age (AGA). The relationship between serum adiponectin levels and insulin-resistance indices measured under OGTT were tested and compared between the two groups.

RESULTS

The SGA group demonstrated significantly reduced serum adiponectin levels than controls (12.6 +/- 6.9 vs 13.2 +/- 6.4 microg/ml, P = 0.02) and the difference remained significant when the key regulatory factors were taken into account (P = 0.008). In the AGA group, fasting I/G taken as an insulin-resistance index negatively correlated with serum adiponectin concentrations (P = 0.02), while the relationship followed a U-shape with increased fasting I/G ratio despite high concentrations of serum adiponectin in the SGA group (P = 0.12).

CONCLUSION

Subjects born SGA demonstrated significantly reduced serum adiponectin levels, which were not related to insulin-resistance indices in comparison to what observed in age-matched subjects born AGA. Although this defect in adiponectin production and in its insulin-sensitizing action remains to be elucidated at the molecular level, it strengthens the critical contribution of the adipose tissue in the metabolic complications associated with reduced fetal growth.

Smallness for gestational age is associated with persistent change in insulin-like growth factor I (IGF-I) and the ratio of IGF-I/IGF-binding protein-3 in adulthood

CONTEXT

Implication of the IGF-IGF-binding protein (IGFBP) axis in the development of metabolic and cardiovascular diseases has been well documented. It has also been shown that an adverse intrauterine environment alters the IGF-IGFBP axis during childhood.

OBJECTIVE

The objective of this study was to investigate whether these alterations persist into adulthood.

DESIGN AND METHODS

Fasting serum IGF-I, IGFBP-3, and insulin concentrations were measured, and their determinants were analyzed in a cohort of young adult subjects (22 yr of age) born either small (SGA; n = 461) or appropriate (AGA; n = 568) for gestational age.

RESULTS

In adulthood, subjects born SGA had significantly lower mean serum IGF-I (320 +/- 137 vs. 348 +/- 143 microg/liter; P = 0.0015), IGFBP-3 (4700 +/- 700 vs. 4800 +/- 800 microg/liter; P = 0.04), and IGF-I/IGFBP-3 ratio (0.067 +/- 0.026 vs. 0.072 +/- 0.025; P = 0.01) than those born AGA. The fasting IGF-I concentration and the IGF-I/IGFBP-3 ratio were significantly inversely associated with age, body mass index, smoking, and oral contraception and were positively related to birth weight and fasting insulin levels. The IGFBP-3 concentration was significantly negatively correlated to age and smoking and was positively related to insulin concentration and oral contraception. After adjustment for age, height, body mass index, gender, smoking, and oral contraception, the mean IGF-I concentration and the mean IGF-I/IGFBP-3 ratio remained significantly lower in the SGA compared with the AGA group (P = 0.003 and P = 0.01, respectively).

CONCLUSIONS

Serum IGF-I concentrations and the IGF-I/IGFBP-3 ratio are lower in adult subjects born SGA. Although the origin of this persisting alteration of the IGF-IGFBP axis in adulthood needs to be elucidated, its potential contribution to the long-term metabolic and cardiovascular complications associated with fetal growth restriction is important to consider in the future.

Dynamic change in adiposity from fetal to postnatal life is involved in the metabolic syndrome associated with reduced fetal growth

AIMS/HYPOTHESIS

The aims of this study were to establish the role of insulin resistance in the metabolic syndrome associated with restricted fetal growth and to characterise the fetal and postnatal determinants responsible for the long-term metabolic outcome.

METHODS

The study population consisted of adults selected on birth data from a maternity registry and born either small for gestational age (SGA) (n=734, birthweight<tenth percentile) or appropriate for gestational age (AGA) (n=886, 25th<birthweight<75th percentile) and in whom clinical and metabolic parameters of the metabolic syndrome were measured at 22 years of age.

RESULTS

Mean values of all components of the metabolic syndrome significantly differed between the two groups, with the metabolic syndrome observed in 2.3% of the SGA group and in 4 per thousand of the AGA group (p=0.0004). In SGA subjects, the upper tertile of fasting insulinaemia was associated with the highest values of systolic (p=0.001) and diastolic (p=0.02) blood pressure, triglyceridaemia (p=0.005) and glycaemia at fasting (p=0.0001) and during OGTT (p=0.0001). In SGA subjects, insulin resistance was not related to birthweight itself (p=0.26), but correlated negatively with BMI at birth (p=0.03) and positively with the subsequent postnatal catch-up in BMI (p=0.009).

CONCLUSIONS/INTERPRETATION

Insulin resistance is the keystone of metabolic syndrome associated with SGA, and its origin should be sought in the fetal development process of adiposity that is responsible for postnatal growth and the later development of insulin resistance.

In situ lipolytic regulation in subjects born small for gestational age

OBJECTIVE

Subjects born small for gestational age (SGA) who are prone to develop insulin resistance in adulthood display an abnormal development pattern of the adipose tissue during fetal and postnatal life. Since the lipolytic activity of the adipose tissue is critical in the development of insulin resistance, the purpose of this study was to investigate whether SGA itself might affect lipolysis regulation.

STUDY DESIGN

We studied the effect of catecholamines, by local injection of isoproterenol, and the effect of insulin, using two-step infusion at 8 and 40 mU/m2/min, on the in situ lipolysis of the subcutaneous abdominal adipose tissue of 23 subjects born SGA and 23 born appropriate for gestational age (AGA), using the microdialysis technique.

RESULTS

Under isoproterenol infusion, the increase in dialysate glycerol concentration was significantly 1.5-fold higher in the SGA than in the AGA group (P=0.02) and induced a 20% increase in the plasma FFA concentration (P=0.04), whereas no significant increase was observed in the AGA group. The antilipolytic action of insulin on dialysate glycerol concentration was similar in both groups throughout the insulin infusion.

CONCLUSION

Subjects born SGA demonstrated a hyperlipolytic reactivity to catecholamines, which might be regarded as an additional deleterious component of the insulin resistance associated with SGA. In contrast, being born SGA does not directly affect the antilipolytic action of insulin, showing that it does not play a major role in causing the long-term metabolic complications associated with reduced fetal growth.

An assessment of pancreatic endocrine function and insulin sensitivity in patients with transient neonatal diabetes in remission

AIMS

To examine derived indices of beta cell function, peripheral insulin sensitivity, and the pancreatic response to intravenous glucose loading in children with a previous history of transient neonatal diabetes currently in remission, repeated after a period of two or more years.

METHODS

The standard intravenous glucose tolerance test (IVGTT) was used to measure the first phase insulin response (FPIR) cumulatively at one and three minutes. In addition, fasting insulin and glucose values were used to estimate insulinogenic indices (beta cell function) and QUICKI (insulin sensitivity).

PATIENTS

Six patients with known previous transient neonatal diabetes currently in remission with no exogenous insulin requirement were tested. Control data from 15 children of a similar age were available for derived fasting indices of beta cell functional capacity and insulin sensitivity.

RESULTS

One child had a subnormal insulin secretory response to intravenous glucose that remained abnormal two and four years later. The other children had relatively normal or entirely normal responses over two years. Measures of beta cell function and insulin sensitivity in the fasting state showed comparable results to those obtained from normal controls.

CONCLUSIONS

Most children with transient neonatal diabetes in remission have no evidence of beta cell dysfunction or insulin resistance in the fasting state, although they might have been expected to show subtle defects given the tendency to relapse in adolescence. Measures of insulin response to intravenous glucose loading are often normal but suggest future recurrence if profoundly abnormal.

[Recommendations for the standardization of growth hormone assays]

The diagnosis of growth hormone (GH) deficiency is based on the GH biological response to pharmacological stimulation tests. The cut-off value defining normality is the same whatever the GH assay used. In a group of the French Society for Clinical Biology (SFBC), we have evaluated whether differences between the GH concentrations obtained with the 9 commercial GH assays available in France exist or not. The study samples consisted of 72 serum pools and serial dilutions of the recombinant GH 22 kDa international standard, IS 98/574. These dilutions were performed by using 3 different diluents: the specific diluent provided by the manufacturers and thus different from one assay to another, serum without GH and heparin plasma without GH. Despite being calibrated against the same international standard, the different assays proposed variable conversion factors between microg and mIU, and we decided to express the results in mIU. The GH concentrations obtained for the 72 serum pools with the 9 assays were highly correlated, but absolute concentrations were significantly different from one assay to another. In particular, the ratio between the concentrations measured with both assays giving the lowest and highest concentration in the same sample respectively was about 50%. In the recovery test executed by adding the international standard, the slope of the regression curve describing the relationship between expected and measured concentrations was different of 1 in all but one assay. Furthermore, for a given assay and a given expected concentration, the measured values were sometimes different by up to 30% depending on the diluent used. These results led us to advise the manufacturers to calibrate their assays against the recombinant GH international standard, IS 98/574, to take into account the matrix effect detected in our study and to use the official conversion factor of 3 mIU/microg. Waiting for this new calibration, it is recommended that the results should be expressed in mIU/L and that serum samples should be used for the measurement of GH instead of plasma samples.