Poor sleep and shift work associate with increased blood pressure and inflammation in UK Biobank participants

Disrupted circadian rhythms have been linked to an increased risk of hypertension and cardiovascular disease. However, many studies show inconsistent findings and are not sufficiently powered for targeted subgroup analyses. Using the UK Biobank cohort, we evaluate the association between circadian rhythm-disrupting behaviours, blood pressure (SBP, DBP) and inflammatory markers in >350,000 adults with European white British ancestry. The independent U-shaped relationship between sleep length and SBP/DBP is most prominent with a low inflammatory status. Poor sleep quality and permanent night shift work are also positively associated with SBP/DBP. Although fully adjusting for BMI in the linear regression model attenuated effect sizes, these associations remain significant. Two-sample Mendelian Randomisation (MR) analyses support a potential causal effect of long sleep, short sleep, chronotype, daytime napping and sleep duration on SBP/DBP. Thus, in the current study, we present a positive association between circadian rhythm-disrupting behaviours and SBP/DBP regulation in males and females that is largely independent of age.

Mineralocorticoid receptor signalling in primary aldosteronism

Primary aldosteronism, or Conn syndrome, is the most common endocrine cause of hypertension. It is associated with a higher risk of cardiovascular, metabolic and renal diseases, as well as a lower quality of life than for hypertension due to other causes. The multi-systemic effects of primary aldosteronism can be attributed to aldosterone-mediated activation of the mineralocorticoid receptor in a range of tissues. In this review, we explore the signalling pathways of the mineralocorticoid receptor, with a shift from the traditional focus on the regulation of renal sodium-potassium exchange to a broader understanding of its role in the modulation of tissue inflammation, fibrosis and remodelling. The appreciation of primary aldosteronism as a multi-system disease with tissue-specific pathophysiology may lead to more vigilant testing and earlier institution of targeted interventions.

Structure-function relationships of the aldosterone receptor

The cellular response to the adrenal steroid aldosterone is mediated by the mineralocorticoid receptor (MR), a member of the nuclear receptor superfamily of ligand-dependent transcription factors. The MR binds more than one physiological ligand with binding at the MR determined by pre-receptor metabolism of glucocorticoid ligands by 11β hydroxysteroid dehydrogenase type 2. The MR has a wide tissue distribution with multiple roles beyond the classical role in electrolyte homeostasis including cardiovascular function, immune cell signaling, neuronal fate and adipocyte differentiation. The MR has three principal functional domains, an N-terminal ligand domain, a central DNA binding domain and a C-terminal, ligand binding domain, with structures having been determined for the latter two domains but not for the whole receptor. MR signal-transduction can be best viewed as a series of interactions which are determined by the conformation conferred on the receptor by ligand binding. This conformation then determines subsequent intra- and inter-molecular interactions. These interactions include chromatin, coregulators and other transcription factors, and additional less well characterized cytoplasmic non-genomic effects via crosstalk with other signaling pathways. This chapter will provide a review of MR structure and function, and an analysis of the critical interactions involved in MR-mediated signal transduction, which contribute to ligand- and tissue-specificity. Understanding the relevant mechanisms for selective MR signaling in terms of these interactions opens the possibility of novel therapeutic approaches for the treatment of MR-mediated diseases.

Ciclesonide activates glucocorticoid signaling in neonatal rat lung but does not trigger adverse effects in the cortex and cerebellum

Synthetic glucocorticoids (sGCs) such as dexamethasone (DEX), while used to mitigate inflammation and disease progression in premature infants with severe bronchopulmonary dysplasia (BPD), are also associated with significant adverse neurologic effects such as reductions in myelination and abnormalities in neuroanatomical development. Ciclesonide (CIC) is a sGC prodrug approved for asthma treatment that exhibits limited systemic side effects. Carboxylesterases enriched in the lower airways convert CIC to the glucocorticoid receptor (GR) agonist des-CIC. We therefore examined whether CIC would likewise activate GR in neonatal lung but have limited adverse extra-pulmonary effects, particularly in the developing brain. Neonatal rats were administered subcutaneous injections of CIC, DEX or vehicle from postnatal days 1-5 (PND1-PND5). Systemic effects linked to DEX exposure, including reduced body and brain weight, were not observed in CIC treated neonates. Furthermore, CIC did not trigger the long-lasting reduction in myelin basic protein expression in the cerebral cortex nor cerebellar size caused by neonatal DEX exposure. Conversely, DEX and CIC were both effective at inducing the expression of select GR target genes in neonatal lung, including those implicated in lung-protective and anti-inflammatory effects. Thus, CIC is a promising, novel candidate drug to treat or prevent BPD in neonates given its activation of GR in neonatal lung and limited adverse neurodevelopmental effects. Furthermore, since sGCs such as DEX administered to pregnant women in pre-term labor can adversely affect fetal brain development, the neurological-sparing properties of CIC, make it an attractive alternative for DEX to treat pregnant women severely ill with respiratory illness, such as with asthma exacerbations or COVID-19 infections.

Pubertal growth in height, sitting height and leg length in achondroplasia

Background: Children with achondroplasia (ACH) appear to lack a pubertal growth spurt in height.Aim To explore the growth spurt in height and its segments sitting height and leg length, in a large sample of ACH cases using growth curve modelling.Subjects and methods: Height and sitting height were measured longitudinally in ACH children, and the data were analysed using the SITAR (SuperImposition by Translation and Rotation) growth model, which estimates a mean growth curve and random effects for individuals defining differences in size, pubertal timing and intensity.Results: Out of 402 ACH children, 85 boys and 75 girls aged 7-20 years had respectively 529 and 454 measurements of height and sitting height, with leg length calculated by difference. SITAR analysis identified peaks in mean height velocity at 13.3 and 11.3 years in boys and girls, with peak velocities of 4.3 and 4.4 cm/year. Mean peak velocity for sitting height was 3.0 cm/year, but leg length showed no peak. The SITAR models explained 92% to 99% of the cross-sectional variance.Conclusion: ACH children do experience a growth spurt in puberty, but only half that of control children. The spurt is due entirely to sitting height, with no leg length spurt.

Control of Glucocorticoid Receptor Levels by PTEN Establishes a Failsafe Mechanism for Tumor Suppression

The PTEN tumor suppressor controls cell death and survival by regulating functions of various molecular targets. While the role of PTEN lipid-phosphatase activity on PtdIns(3,4,5)P3 and inhibition of PI3K pathway is well characterized, the biological relevance of PTEN protein-phosphatase activity remains undefined. Here, using knockin (KI) mice harboring cancer-associated and functionally relevant missense mutations, we show that although loss of PTEN lipid-phosphatase function cooperates with oncogenic PI3K to promote rapid mammary tumorigenesis, the additional loss of PTEN protein-phosphatase activity triggered an extensive cell death response evident in early and advanced mammary tumors. Omics and drug-targeting studies revealed that PI3Ks act to reduce glucocorticoid receptor (GR) levels, which are rescued by loss of PTEN protein-phosphatase activity to restrain cell survival. Thus, we find that the dual regulation of GR by PI3K and PTEN functions as a rheostat that can be exploited for the treatment of PTEN loss-driven cancers.

Tanner's tempo of growth in adolescence: recent SITAR insights with the Harpenden Growth Study and ALSPAC

Background: James Tanner emphasised the “tempo” of growth, i.e. the adolescent spurt as summarised by its timing (age at peak velocity or APV) and intensity (peak velocity, PV).

Aim: The paper applies the SITAR growth curve model to pubertal growth data with the aim of clarifying the growth pattern across multiple measurements and the spectrum of APV and PV.

Subjects and methods: Data for 7–20 years on ten anthropometric measurements in 619 children from the Harpenden Growth Study, and on height in 10410 children from the ALSPAC study, were analysed using SITAR (SuperImposition by Translation And Rotation). SITAR models pubertal growth as a mean curve with APV and PV fitted as subject-specific random effects, and a random measurement intercept.

Results: Mean APV for Harpenden girls and boys averaged 12.0 and 13.9 years across the ten measurements. PV expressed as percent per year lay in the narrow range 4–8%. Splitting the ALSPAC subjects into 9 by 5 APV and PV groups and fitting separate SITAR models to each group confirmed SITAR’s good fit while highlighting the spectrum of growth patterns.

Conclusion: SITAR works well to summarise pubertal growth. The disappointment is that Tanner did not live to see it in action.

Sample size and sample composition for constructing growth reference centiles

Growth reference centile charts are widely used in child health to assess weight, height and other age-varying measurements. The centiles are easy to construct from reference data, using the LMS method or GAMLSS (Generalised Additive Models for Location Scale and Shape). However, there is as yet no clear guidance on how to design such studies, and in particular how many reference data to collect, and this has led to study sizes varying widely. The paper aims to provide a theoretical framework for optimally designing growth reference studies based on cross-sectional data. Centiles for weight, height, body mass index and head circumference, in 6878 boys aged 0-21 years from the Fourth Dutch Growth Study, were fitted using GAMLSS. The effect on precision of varying the sample size and the distribution of measurement ages (sample composition) was explored by fitting a series of GAMLSS models to simulated data. Sample composition was defined as uniform on the age^λ scale, where λ was chosen to give constant precision across the age range. Precision was measured on the z-score scale, and was the same for all four measurements, with a standard error of 0.041 z-score units for the median and 0.066 for the 2nd and 98th centiles. Compared to a naïve calculation, the process of smoothing the centiles increased the notional sample size two- to threefold by 'borrowing strength'. The sample composition for estimating the median curve was optimal for λ=0.4, reflecting considerable over-sampling of infants compared to children. However, for the 2nd and 98th centiles, λ=0.75 was optimal, with less infant over-sampling. The conclusion is that both sample size and sample composition need to be optimised. The paper provides practical advice on design, and concludes that optimally designed studies need 7000-25,000 subjects per sex.

Novel mineralocorticoid receptor mechanisms regulate cardiac tissue inflammation in male mice

MR activation in macrophages is critical for the development of cardiac inflammation and fibrosis. We previously showed that MR activation modifies macrophage pro-inflammatory signalling, changing the cardiac tissue response to injury via both direct gene transcription and JNK/AP-1 second messenger pathways. In contrast, MR-mediated renal electrolyte homeostasis is critically determined by DNA-binding-dependent processes. Hence, ascertaining the relative contribution of MR actions via DNA binding or alternative pathways on macrophage behaviour and cardiac inflammation may provide therapeutic opportunities which separate the cardioprotective effects of MR antagonists from their undesirable renal potassium-conserving effects. We developed new macrophage cell lines either lacking MR or harbouring a mutant MR incapable of DNA binding. Western blot analysis demonstrated that MR DNA binding is required for lipopolysaccharide (LPS), but not phorbol 12-myristate-13-acetate (PMA), induction of the MAPK/pJNK pathway in macrophages. Quantitative RTPCR for pro-inflammatory and pro-fibrotic targets revealed subsets of LPS- and PMA-induced genes that were either enhanced or repressed by the MR via actions that do not always require direct MR-DNA binding. Analysis of the MR target gene and profibrotic factor MMP12 identified promoter elements that are regulated by combined MR/MAPK/JNK signalling. Evaluation of cardiac tissue responses to an 8-day DOC/salt challenge in mice selectively lacking MR DNA-binding in macrophages demonstrated levels of inflammatory markers equivalent to WT, indicating non-DNA binding-dependent MR signalling in macrophages is sufficient for DOC/salt-induced tissue inflammation. Our data demonstrate that the MR regulates a macrophage pro-inflammatory phenotype and cardiac tissue inflammation, partially via pathways that do not require DNA binding.

Glucocorticoid signalling drives reduced versican levels in the fetal mouse lung

Glucocorticoid (GC) signaling via the glucocorticoid receptor (GR) is essential for lung maturation in mammals. Previous studies using global or conditional mouse model knockouts of the GR gene have established that GR-mediated signaling in the interstitial mesenchyme of the fetal lung is critical for normal lung development. Screens for downstream GC-targets in conditional mesenchymal GR deficient mouse lung (GRmesKO) identified Versican (Vcan), an important extracellular matrix component and cell proliferation regulator, as a potential GR-regulated target. We show that, of the five major VCAN isoforms, the VCAN-V1 isoform containing the GAGβ domain is the predominant VCAN isoform in the fetal mouse lung distal mesenchyme at both E16.5 and E18.5, whereas the GAGα-specific VCAN-V2 isoform was only localized to the smooth muscle surrounding proximal airways. Both Vcan-V1 mRNA and protein levels were strongly overexpressed in the GRmesKO lung at E18.5. Finally, we investigated the GC regulation of the ECM protease ADAMTS 12 and showed that Adamts 12 mRNA levels were markedly reduced at E18.5 in GRmesKO fetal mouse lung and were strongly induced by both cortisol and betamethasone in cultures of primary rat fetal lung fibroblasts. ADAMTS12 protein immunoreactivity was also strongly increased in the distal lung at E18.5, after dexamethasone treatment in utero. In summary, glucocorticoid signaling via GR represses GAGβ domain-containing VCAN isoforms in distal lung mesenchyme in vivo by repressing Vcan gene expression and, in part, by inducing the ECM protease ADAMTS12, thereby contributing to the control of ECM remodelling and lung cell proliferation prior to birth.

Commentary: Methods for calculating growth trajectories and constructing growth centiles

This commentary rounds off a collection of papers focusing on statistical methods for analysing growth data. In two papers, Anderson and colleagues discuss growth trajectory models in early life, using data on height and weight from the HBGDki initiative, while two papers from Ohuma and Altman review methods for centile construction, with data from the INTERGROWTH‐21^st project used to provide worked examples of centiles for birthweight and fetal head circumference. Anderson et al focus on four growth trajectory models: quadratic Laird‐Ware, SITAR, brokenstick, and FACE, where the latter two fit better than the former two applied to length data in individuals. On this basis, they recommend brokenstick and FACE for future work. However, they do not discuss the timescale on which the growth models assess growth faltering nor the relevance of this timescale to later health outcome. Models that best detect short‐term fluctuations in growth (brokenstick and FACE) may not necessarily be best at predicting later outcome. It is premature to exclude the quadratic Laird‐Ware or SITAR models, which give a parsimonious summary of growth in individuals over a longer timescale. Ohuma and Altman highlight the poor quality of reporting in fetal centile studies, and they provide recommendations for good practice. Their birthweight centiles example illustrates both the power of the GAMLSS software and its capacity for misuse. The longitudinal fetal head circumference centiles are biased such that 5% of infants are below the 3^rd centile and 5% above the 97^th.

Identification of Betamethasone-Regulated Target Genes and Cell Pathways in Fetal Rat Lung Mesenchymal Fibroblasts

Preterm birth is characterized by severe lung immaturity that is frequently treated antenatally or postnatally with the synthetic steroid betamethasone. The underlying cellular targets and pathways stimulated by betamethasone in the fetal lung are poorly defined. In this study, betamethasone was compared with corticosterone in steroid-treated primary cultures of fetal rat lung fibroblasts stimulated for 6 hours and analyzed by whole-cell transcriptome sequencing and glucocorticoid (GC) receptor (GR) chromatin immunoprecipitation sequencing (ChIP-Seq) analysis. Strikingly, betamethasone stimulated a much stronger transcriptional response compared with corticosterone for both induced and repressed genes. A total of 483 genes were significantly stimulated by betamethasone or corticosterone, with 476 stimulated by both steroids, indicating a strong overlap in regulation. Changes in mRNA levels were confirmed by quantitative PCR for eight induced and repressed target genes. Pathway analysis identified cell proliferation and cytoskeletal/cell matrix remodeling pathways as key processes regulated by both steroids. One target, transglutaminase 2 (Tgm2), was localized to fetal lung mesenchymal cells. Tgm2 mRNA and protein levels were strongly increased in fibroblasts by both steroids. Whole-genome GR ChIP-Seq analysis with betamethasone identified GC response element-binding sites close to the previously characterized GR target genes Per1, Dusp1, Fkbp5, and Sgk1 and near the genes identified by transcriptome sequencing encoding Crispld2, Tgm2, Hif3α, and Kdr, defining direct genomic induction of expression in fetal lung fibroblasts via the GR. These results demonstrate that betamethasone stimulates specific genes and cellular pathways controlling cell proliferation and extracellular matrix remodeling in lung mesenchymal fibroblasts, providing a basis for betamethasone's treatment efficacy in preterm birth.

The science of steroids

Steroids are complex lipophilic molecules that have many actions in the body to regulate cellular, tissue and organ functions across the life-span. Steroid hormones such as cortisol, aldosterone, estradiol and testosterone are synthesised from cholesterol in specialised endocrine cells in the adrenal gland, ovary and testis, and released into the circulation when required. Steroid hormones move freely into cells to activate intracellular nuclear receptors that function as multi-domain ligand-dependent transcriptional regulators in the cell nucleus. Activated nuclear receptors modify expression of hundreds to thousands of specific target genes in the genome. Steroid hormone actions in the fetus include developmental roles in the respiratory system, brain, and cardiovascular system. The synthetic glucocorticoid steroid betamethasone is used antenatally to reduce the complications of preterm birth. Development of novel selective partial glucocorticoid receptor agonists may provide improved therapies to treat the respiratory complications of preterm birth and spare the deleterious effects of postnatal glucocorticoids in other organs.

Glucocorticoids influence versican and chondroitin sulphate proteoglycan levels in the fetal sheep lung

BACKGROUND

Prenatal glucocorticoid treatment decreases alveolar tissue volumes and facilitates fetal lung maturation, however the mechanisms responsible are largely unknown. This study examines whether changes in versican levels or sulphation patterns of chondroitin sulphate (CS) side chains, are associated with glucocorticoid-induced reductions in peri-alveolar tissue volumes.

METHODS

Lung tissue was collected from 1) fetal sheep at 131 ± 0.1 days gestational age (GA) infused with cortisol (122-131d GA) to prematurely induce a pre-parturient-like rise in circulating cortisol, 2) fetal sheep at 143d GA bilaterally adrenalectomised (ADX) at 112d GA to remove endogenous cortisol and 3) fetal sheep at 124d GA in which bolus doses (2 × 11.4 mg) of betamethasone were administered to the pregnant ewe. The level and distribution of versican and CS glycosaminoglycans (GAG) were determined using immunohistochemistry (IHC). Fluorophore assisted carbohydrate electrophoresis (FACE) was used to determine changes in CS sulphation patterns.

RESULTS

Cortisol infusion significantly decreased chondrotin-6-sulphate levels (C-6-S) to 16.4 ± 0.7 AU, compared with saline-infused fetuses (18.9 ± 0.7 AU: p = 0.04) but did not significantly alter the level of versican or chondroitin-4-sulphate (C-4-S). ADX significantly increased the level of C-4-S (28.2 ± 2.2 AU), compared with sham-operated fetuses (17.8 ± 2.0 AU; p = 0.006) without altering versican or C-6-S levels. Betamethasone significantly decreased versican, C-4-S and C-6-S in the fetal sheep lung (19.2 ± 0.9 AU, 24.9 ± 1.4 AU and 23.2 ± 1.0 AU, respectively), compared with saline-exposed fetuses (24.3 ± 0.4 AU, p = 0.0004; 33.3±0.6 AU, p = 0.0003; 29.8±1.3 AU, 0.03, respectively).

CONCLUSIONS

These results indicate that glucocorticoids alter versican levels and CS side chain microstructure in alveolar lung tissue. Betamethasone appears to have a greater impact on versican and CS side chains than cortisol.

In vivo evidence that RBM5 is a tumour suppressor in the lung

Cigarette smoking is undoubtedly a risk factor for lung cancer. Moreover, smokers with genetic mutations on chromosome 3p21.3, a region frequently deleted in cancer and notably in lung cancer, have a dramatically higher risk of aggressive lung cancer. The RNA binding motif 5 (RBM5) is one of the component genes in the 3p21.3 tumour suppressor region. Studies using human cancer specimens and cell lines suggest a role for RBM5 as a tumour suppressor. Here we demonstrate, for the first time, an in vivo role for RBM5 as a tumour suppressor in the mouse lung. We generated Rbm5 loss-of-function mice and exposed them to a tobacco carcinogen NNK. Upon exposure to NNK, Rbm5 loss-of-function mice developed lung cancer at similar rates to wild type mice. As tumourigenesis progressed, however, reduced Rbm5 expression lead to significantly more aggressive lung cancer i.e. increased adenocarcinoma nodule numbers and tumour size. Our data provide in vivo evidence that reduced RBM5 function, as occurs in a large number of patients, coupled with exposure to tobacco carcinogens is a risk factor for an aggressive lung cancer phenotype. These data suggest that RBM5 loss-of-function likely underpins at least part of the pro-tumourigenic consequences of 3p21.3 deletion in humans.

Fresh Noncultured Endothelial Progenitor Cells Improve Neonatal Lung Hyperoxia-Induced Alveolar Injury

Treatment of preterm human infants with high oxygen can result in disrupted lung alveolar and vascular development. Local or systemic administration of endothelial progenitor cells (EPCs) is reported to remedy such disruption in animal models. In this study, the effects of both fresh (enriched for KDR) and cultured bone marrow (BM)-derived cell populations with EPC characteristics were examined following hyperoxia in neonatal mouse lungs. Intraperitoneal injection of fresh EPCs into five-day-old mice treated with 90% oxygen resulted in full recovery of hyperoxia-induced alveolar disruption by 56 days of age. Partial recovery in septal number following hyperoxia was observed following injection of short-term cultured EPCs, yet aberrant tissue growths appeared following injection of long-term cultured cells. Fresh and long-term cultured cells had no impact on blood vessel development. Short-term cultured cells increased blood vessel number in normoxic and hyperoxic mice by 28 days but had no impact on day 56. Injection of fresh EPCs into normoxic mice significantly reduced alveolarization compared with phosphate buffered saline-injected normoxic controls. These results indicate that fresh BM EPCs have a higher and safer corrective profile in a hyperoxia-induced lung injury model compared with cultured BM EPCs but may be detrimental to the normoxic lung. The appearance of aberrant tissue growths and other side effects following injection of cultured EPCs warrants further investigation. Stem Cells Translational Medicine 2017;6:2094-2105.

Hydroxysteroid dehydrogenase HSD1L is localised to the pituitary-gonadal axis of primates

Steroid hormones play clinically important and specific regulatory roles in the development, growth, metabolism, reproduction and brain function in human. The type 1 and 2 11-beta hydroxysteroid dehydrogenase enzymes (11β-HSD1 and 2) have key roles in the pre-receptor modification of glucocorticoids allowing aldosterone regulation of blood pressure, control of systemic fluid and electrolyte homeostasis and modulation of integrated metabolism and brain function. Although the activity and function of 11β-HSDs is thought to be understood, there exists an open reading frame for a distinct 11βHSD-like gene; HSD11B1L, which is present in human, non-human primate, sheep, pig and many other higher organisms, whereas an orthologue is absent in the genomes of mouse, rat and rabbit. We have now characterised this novel HSD11B1L gene as encoded by 9 exons and analysis of EST library transcripts indicated the use of two alternate ATG start sites in exons 2 and 3, and alternate splicing in exon 9. Relatively strong HSD11B1L gene expression was detected in human, non-human primate and sheep tissue samples from the brain, ovary and testis. Analysis in non-human primates and sheep by immunohistochemistry localised HSD11B1L protein to the cytoplasm of ovarian granulosa cells, testis Leydig cells, and gonadatroph cells in the anterior pituitary. Intracellular localisation analysis in transfected human HEK293 cells showed HSD1L protein within the endoplasmic reticulum and sequence analysis suggests that similar to 11βHSD1 it is membrane bound. The endogenous substrate of this third HSD enzyme remains elusive with localisation and expression data suggesting a reproductive hormone as a likely substrate.

The effect of galsulfase enzyme replacement therapy on the growth of patients with mucopolysaccharidosis VI (Maroteaux-Lamy syndrome)

Mucopolysaccharidosis (MPS) VI is an autosomal recessive lysosomal storage disorder arising from deficient activity of N-acetylgalactosamine-4-sulfatase (arylsulfatase B) and subsequent intracellular accumulation of the glycosaminoglycans (GAGs) dermatan sulfate and chondroitin-4-sulfate. Manifestations are multi-systemic and include skeletal abnormalities such as dysostosis multiplex and short stature. Reference height-for-age growth charts for treatment-naïve MPS VI patients have been published for both the slowly and rapidly progressing populations. Categorization of disease progression for these charts was based on urinary GAG (uGAG) level; high (>200μg/mg creatinine) levels identified subjects as rapidly progressing. Height data for 141 patients who began galsulfase treatment by the age of 18years were collected and stratified by baseline uGAG level and age at ERT initiation in 3-year increments. The reference MPS VI growth charts were used to calculate change in Z-score from pre-treatment baseline to last follow-up. Among patients with high baseline uGAG levels, galsulfase ERT was associated with an increase in Z-score for those beginning treatment at 0-3, >3-6, >6-9, >9-12, and >12-15years of age (p<0.05). Increases in Z-score were not detected for patients who began treatment between 15 and 18years of age, nor for patients with low (≤200μg/mg creatinine) baseline uGAG levels, regardless of age at treatment initiation. The largest positive deviation from untreated reference populations was seen in the high uGAG excretion groups who began treatment by 6years of age, suggesting an age- and severity-dependent impact of galsulfase ERT on growth.

Fifty years of child height and weight in Japan and South Korea: Contrasting secular trend patterns analyzed by SITAR

Objectives Japanese and South Koreans have traditionally been shorter than Europeans, but have recently become appreciably taller. The aim was to quantify the secular trend patterns in height and weight growth in the two countries over 50 years using the SITAR growth curve model.

Methods Data on mean height and weight by sex in 1‐year age groups from 1 to 20 years were obtained by decade in South Korea (1965–2005) and Japan (1950–2010). The data were analyzed using SITAR (SuperImposition by Translation And Rotation), which estimates a mean curve and three adjustments–size, timing and intensity–reflecting how the individual surveys differ from the mean. A sensitivity analysis compared results for the Japanese data based on cohort as well as period.

Results Growth patterns in the two countries changed dramatically over the study period, affecting not only height and weight but also developmental age, in that the growth period advanced in timing and shrank in duration. SITAR fitted the data well. The trends were larger in South Korea than Japan, and puberty timing in Japan stabilized by 1970. Most of the height increment seen in adults had already accrued by age 1.5 years, whereas the adult weight increment accrued throughout childhood.

Conclusions The secular height trend in these countries represents increased growth in the long bones during infancy, so it can be viewed as the inverse of stunting. There are striking country differences in growth pattern, but they are not easily explained by differences in national income, diet or lifestyle.

30 YEARS OF THE MINERALOCORTICOID RECEPTOR: Mineralocorticoid receptor null mice: informing cell-type-specific roles

The mineralocorticoid receptor (MR) mediates the actions of two important adrenal corticosteroid hormones, aldosterone and cortisol. The cell signalling roles of the MR in vivo have expanded enormously since the cloning of human MR gene 30 years ago and the first MR gene knockout in mice nearly 20 years ago. Complete ablation of the MR revealed important roles postnatally for regulation of kidney epithelial functions, with MR-null mice dying 1-2 weeks postnatally from renal salt wasting and hyperkalaemia, with elevated plasma renin and aldosterone. Generation of tissue-selective MR-deficient mice using Cre recombinase-LoxP gene targeting has made it possible to analyse mice lacking MR only in specific cell types. Targeting renal-specific MR has differentiated roles in specific compartments of the kidney. Ablating MR in neurons of the forebrain reinforced important roles of the MR in response to stress, behaviour and anxiety, but suggested a minimal role in maintaining basal HPA axis tone. Deletion of the MR in macrophages and other cell types of the cardiovascular system clearly defined important roles for the regulation of cardiovascular physiology and pathophysiology. Knockdown of MR mRNA in vivo using antisense/siRNA approaches, and similarly MR overexpression, has provided useful rodent models to study physiological roles of MR signalling in vivo More recently, targeted mutation of specific domains of the MR such as the DBD has defined genomic vs non-genomic roles in vivo New tissue-selective MR-null models are required to define roles of MR signalling in other regions of the brain, the eye, gastrointestinal tract, lung, skin, breast and gonadal organs.

The International Growth Standard for Preadolescent and Adolescent Children: Statistical Considerations

This article discusses statistical considerations for the design of a new study intended to provide an International Growth Standard for Preadolescent and Adolescent Children, including issues such as cross-sectional, longitudinal, and mixed designs; sample-size derivation for the number of populations and number of children per population; modeling of growth centiles of height, weight, and other measurements; and modeling of the adolescent growth spurt. The conclusions are that a mixed longitudinal design will provide information on both growth distance and velocity; samples of children from 5 to 10 sites should be suitable for an international standard (based on political rather than statistical arguments); the samples should be broadly uniform across age but oversampled during puberty, and should include data into adulthood. The LMS method is recommended for constructing measurement centiles, and parametric or semiparametric approaches are available to estimate the timing of the adolescent growth spurt in individuals. If the new standard is to be grafted onto the 2006 World Health Organization (WHO) reference, caution is needed at the join point of 5 years, where children from the new standard are likely to be appreciably more obese than those from the WHO reference, due to the rising trends in obesity and the time gap in data collection between the two surveys.

Using Super-Imposition by Translation And Rotation (SITAR) to relate pubertal growth to bone health in later life: the Medical Research Council (MRC) National Survey of Health and Development

Background: To explore associations between pubertal growth and later bone health in a cohort with infrequent measurements, using another cohort with more frequent measurements to support the modelling, data from the Medical Research Council (MRC) National Survey of Health and Development (2–26 years, 4901/30 004 subjects/measurements) and the Avon Longitudinal Study of Parents And Children (ALSPAC) (5–20 years) (10 896/74 120) were related to National Survey of Health and Development (NSHD) bone health outcomes at 60–64 years.

Methods: NSHD data were analysed using Super-Imposition by Translation And Rotation (SITAR) growth curve analysis, either alone or jointly with ALSPAC data. Improved estimation of pubertal growth parameters of size, tempo and velocity was assessed by changes in model fit and correlations with contemporary measures of pubertal timing. Bone outcomes of radius [trabecular volumetric bone mineral density (vBMD) and diaphysis cross-sectional area (CSA)] were regressed on the SITAR parameters, adjusted for current body size.

Results: The NSHD SITAR parameters were better estimated in conjunction with ALSPAC, i.e. more strongly correlated with pubertal timing. Trabecular vBMD was associated with early height tempo, whereas diaphysis CSA was related to weight size, early tempo and slow velocity, the bone outcomes being around 15% higher for the better vs worse growth pattern.

Conclusions: By pooling NSHD and ALSPAC data, SITAR more accurately summarized pubertal growth and weight gain in NSHD, and in turn demonstrated notable associations between pubertal timing and later bone outcomes. These associations give insight into the importance of the pubertal period for future skeletal health and osteoporosis risk.

Aldosterone-Mediated Renal Sodium Transport Requires Intact Mineralocorticoid Receptor DNA-Binding in the Mouse

The classic role of mineralocorticoid receptor (MR) is to promote sodium transport in epithelial tissues. However, the MR is also expressed in a range of tissues in which its role appears unrelated to sodium transport, and under normal physiological conditions, it may be responding to cortisol (corticosterone in rodents) rather than aldosterone. The relative importance of transcriptional mechanisms such as classical genomic signaling via a hormone response element, transrepression of other transcription factors, and nongenomic signaling is not clear, particularly in nonepithelial tissues. The goal of the present study was to define the role of the different signaling pathways for the MR by separating the functional role of classic genomic signaling, mediated by DNA binding, from these two other mechanisms. We used gene targeting to generate mice in which serine is substituted for cysteine at codon 603 in the MR; this mutation precludes DNA binding. These MR C603S mutant mice either die at birth or fail to thrive, lose weight, and die between days 10 and 13 in a manner similar to that observed previously for mice null for the MR gene. Renal expression and cellular localization of MR C603S by immunohistochemistry was equivalent to control mice. MR C603S mice were rescued by twice-daily saline injections. Despite increased aldosterone levels, renal expression of aldosterone-induced genes was not increased. This unique mouse model demonstrates that DNA binding is essential for the epithelial MR response and will provide the basis for analysis of nonclassical signaling of the MR in nonepithelial tissues.

The evidential value of developmental age imaging for assessing age of majority

Aim: To consider the evidential value of developmental age images for identifying age of majority.

Methods: The published literature on hand–wrist X-rays, MRI scans of the distal radius and orthopantomograms of the lower left third molar is considered in terms of the mean age of attainment of the adult appearance and the diagnostic test performance of the adult appearance to predict adult status, either administratively (under-17 football) or forensically.

Results: The mean age of attainment of a mature hand-wrist X-ray is under 18 years and most individuals are mature before age 18. For the MRI wrist scan and the third molar the age of attainment is over 19 years and the adult appearance is an indicator of adulthood, while the immature appearance is uninformative about likely age. So MRI and third molars have high specificity, but low sensitivity.

Conclusions: Bone age assessed by hand–wrist X-ray is uninformative and should not be used. The adult appearance of MRI wrist scans and third molars provide evidence of being over-age, although there remains a small risk of minors being misclassified as adult. The immature appearance is uninformative about likely age and, overall, more than one third of assessments are wrong.

Trop2: from development to disease

BACKGROUND

Trop2 was first discovered as a biomarker of invasive trophoblast cells. Since then most research has focused on its role in tumourigenesis because it is highly expressed in the vast majority of human tumours and animal models of cancer. It is also highly expressed in stem cells and in many organs during development.

RESULTS

We review the multifaceted role of Trop2 during development and tumourigenesis, including its role in regulating cell proliferation and migration, self-renewal, and maintenance of basement membrane integrity. We discuss the evolution of Trop2 and its related protein Epcam (Trop1), including their distinct roles. Mutation of Trop2 leads to gelatinous drop-like corneal dystrophy, whereas over-expression of Trop2 in human tumours promotes tumour aggressiveness and increases mortality. Although Trop2 expression is sufficient to promote tumour growth, the surprising discovery that Trop2-null mice have an increased risk of tumour development has highlighted the complexity of Trop2 signaling. Recently, studies have begun to identify the mechanisms underlying TROP2’s functions, including regulated intramembrane proteolysis or specific interactions with integrin b1 and claudin proteins.

CONCLUSIONS

Understanding the mechanisms underlying TROP2 signaling will clarify its role during development, aid in the development of better cancer treatments and unlock a promising new direction in regenerative medicine.

Glucocorticoid regulation of lung development: lessons learned from conditional GR knockout mice

Glucocorticoid (GC) steroid hormones have well-characterized roles in the regulation of systemic homeostasis, yet less understood is their known role in utero to mature the developing respiratory system in preparation for birth. During late gestation, endogenously produced GCs thin the interstitial tissue of the lung, causing the vasculature and future airspaces to come into close alignment, allowing for efficient gas exchange at birth. More potent synthetic GCs are also used worldwide to reduce the severity of respiratory distress suffered by preterm infants; however, their clinical benefits are somewhat offset by potential detrimental long-term effects on health and development. Here, we review the recent literature studying both global and conditional gene-targeted respiratory mouse models of either GC deficiency or glucocorticoid receptor ablation. Although some discrepancies exist between these transgenic mouse strains, these models have revealed specific roles for GCs in particular tissue compartments of the developing lung and identify the mesenchyme as the critical site for glucocorticoid receptor-mediated lung maturation, particularly for the inhibition of cell proliferation and epithelial cell differentiation. Specific mesenchymal and epithelial cell-expressed gene targets that may potentially mediate the effect of GCs have also been identified in these studies and imply a GC-regulated system of cross talk between compartments during lung development. A better understanding of the specific roles of GCs in specific cell types and compartments of the fetal lung will allow the development of a new generation of selective GC ligands, enabling better therapeutic treatments with fewer side effects for lung immaturity at birth in preterm infants.

The effect of prepubertal calcium carbonate supplementation on skeletal development in Gambian boys-a 12-year follow-up study

CONTEXT

Calcium intake during growth is essential for future bone health but varies widely between individuals and populations. The impact on bone of increasing calcium intake is unknown in a population where low calcium intake, stunting, and delayed puberty are common.

OBJECTIVE

To determine the effect of prepubertal calcium supplementation on mean age at peak velocity for bone growth and mineral accrual.

DESIGN AND SETTING

Prospective follow-up of boys in rural Gambia, West Africa, who had participated in a double-blind, randomized, placebo-controlled trial of calcium supplementation.

PARTICIPANTS

Eighty boys, initially aged 8.0-11.9 years, were followed up for 12 years.

INTERVENTIONS

Subjects received 1 year of calcium carbonate supplementation (1000 mg daily, 5 d/wk).

MAIN OUTCOME MEASURES

Dual-energy x-ray absorptiometry measurements were carried out for whole body (WB), lumbar spine, and total hip bone mineral content, bone area (BA), and WB lean mass. Super imposition by translation and rotation models was made to assess bone growth.

RESULTS

Age at peak velocity was consistently earlier in the calcium group compared to the placebo group, for WB bone mineral content (mean, -6.2 [SE, 3.1]; P = .05), WB BA (mean, -7.0 [SE, 3.2] mo; P = .03), lumbar spine and total hip BA. By young adulthood, supplementation did not change the amount of bone accrued (mineral or size) or the rate of bone growth.

CONCLUSIONS

Twelve months of prepubertal calcium carbonate supplementation in boys with a low calcium diet advanced the adolescent growth spurt but had no lasting effect on bone mineral or bone size. There is a need for caution when applying international recommendations to different populations.

A mixed effects model to estimate timing and intensity of pubertal growth from height and secondary sexual characteristics

Aim

To estimate and compare pubertal growth timing and intensity in height, Tanner stage markers and testis volume.

Subjects and methods

Data on height, genital stage, breast stage and pubic hair stage, testis volume and menarche in 103 boys and 74 girls from the Edinburgh Longitudinal Growth Study were analysed. The SITAR model for height and a novel mixed effects logistic model for Tanner stage and testis volume provided estimates of peak velocity (PV, intensity) and age at peak velocity (APV, timing), both overall (from fixed effects) and for individuals (random effects).

Results

Based on the six markers, mean APV was 13.0–14.0 years in boys and 12.0–13.1 years in girls, with between-subject standard deviations of ∼1 year. PV for height was 8–9 cm/year by sex and for testis volume 6 ml/year, while Tanner stage increased by 1.2–1.8 stages per year at its peak. The correlations across markers for APV were 0.6–0.8 for boys and 0.8–0.92 for girls, very significantly higher for girls (p = 0.005). Correlations for PV were lower, −0.2–0.6.

Conclusions

The mixed effects models perform well in estimating timing and intensity in individuals across several puberty markers. Age at peak velocity correlates highly across markers, but peak velocity less so.

Mesenchymal glucocorticoid receptor regulates the development of multiple cell layers of the mouse lung

Endogenous glucocorticoid (GC) hormones, signaling via the GC receptor (GR), are essential for normal lung development, and synthetic GCs are routinely used to treat respiratory disorders of very preterm babies. Germline GR knockout (GR(-/-)) mice show immature lung morphology and severe lung cellular hyperplasia during embryogenesis and die at birth due to respiratory failure. Two recent studies have reported contradictory results regarding the necessity for GR expression in specific lung germ layers during respiratory maturation. We further investigate in detail the lung phenotype in mice with a conditional deletion of GR in the endothelium, mesenchyme, and lung epithelium. We show that loss of GR in the mesenchyme alone produces a retarded lung phenotype almost identical to that of germline GR(-/-) mice, including severe postnatal lethality and lung cell hyperplasia. Loss of GR in lung epithelial cells and the endothelium had no gross effect on survival or lung morphology, but loss of epithelial GR caused increased cell proliferation in multiple compartments. Mesenchymal GR loss also produced increased epithelial cell proliferation, implying the existence of GC-regulated germ layer cross-talk. Protein levels of GR-mediated cell cycle regulators, including the cyclin-dependent kinase inhibitor p21(CIP1) and the growth factor midkine, were unaffected by mesenchymal GR deletion, yet expression of the extracellular matrix proteoglycan versican was up-regulated in the distal lung on loss of mesenchymal GR. These results show that GR-mediated signaling from the mesenchyme regulates respiratory maturation and ultimately survival at birth and that a key GR-repressed transcriptional target in lung mesenchymal cells is versican.

Transient vascular and long-term alveolar deficits following a hyperoxic injury to neonatal mouse lung

Background

The lungs of very preterm human babies display deficits in alveolarization and vascularization as a result of the clinical use of high oxygen treatment (leading to hyperoxia) required to decrease the risk of mortality. Detailed analyses of the persistence of the respiratory deficits following this treatment and means to restore a normal state have not been investigated in full detail. In this study, high oxygen administration to neonatal mouse lungs was established as a proxy to hyperoxia in human preterm infant lungs, to better characterize the associated deficits and thus provide a means to assist in the development of treatments in the future.

Methods

Ninety percent oxygen was administered to newborn mice for four consecutive days. The effects of this treatment upon alveolarization and vascularization were investigated by morphometric, histochemical, immunohistochemical and protein analyses at day five (D5), D28 and D56 postpartum.

Results

Relative to control untreated lungs, septation of hyperoxic lungs was significantly reduced and airspaces were significantly enlarged at all stages examined. Furthermore, compared to controls, the number of secondary septa per tissue area was significantly reduced at D5, significantly increased at D28 and then the same as controls at D56. Analysis of vascularization parameters indicated a reduction in mature blood vessel number and the amount of Pecam1 at D5. Both of these parameters returned to control levels by D28.

Conclusions

This study suggests that administration of high oxygen to underdeveloped lungs has a transient reductive effect on secondary septal number and pulmonary vascularization and a significant long-term reduction in alveolarization persisting into adulthood. This model can be used for future research of premature lung disease therapies in humans, addressing these short term septal and vascular and long term alveolar deficits, specifically relating to injury by hyperoxia.

Height, adiposity and hormonal cardiovascular risk markers in childhood: how to partition the associations?

Objective:

Obesity is associated with rapid growth during childhood. There is uncertainty over how to adjust for body size, when using adiposity as a proxy for cardiovascular risk. We studied associations of height, body composition (by dual-energy X-ray absorptiometry) and cardiovascular risk markers (insulin resistance (IR), leptin) in children.

Methods:

Using partial correlations in 172 children aged 7–12 years, we investigated associations of (a) fat mass with IR or leptin, adjusting for height or lean mass, and (b) height or lean mass with IR or leptin, adjusting for fat mass. Analyses were conducted both cross-sectionally at each age, and for changes between 7 and 12 years.

Results:

Height, fat mass, lean mass, IR and leptin were all inter-correlated at all ages. Although fat mass was strongly associated with IR and leptin, height was independently negatively associated with leptin (whole sample, adjusting for age: boys r=−0.12, girls r=−0.13; P<0.001). Independent of adiposity, height was also associated with insulin IR (whole sample, adjusting for age: boys r=0.11, girls r=0.20; P<0.001). When analysed by year of age, these associations tended to remain significant at older ages. Change in height from 7 to 12 years was also associated with change in IR (boys: r=0.18, P<0.05; girls: r=0.34, P<0.01), independently of change in adiposity, with similar findings for lean mass.

Conclusions:

During childhood, markers of cardiovascular risk have a complex profile, associated with growth as well as fat accumulation. Taller and faster-growing children have elevated risk markers, independently of their adiposity. These findings have implications for the interpretation of pediatric indices of adiposity that aim to adjust for body size. Adiposity indices that perform best at summarizing metabolic risk may not be those that perform best at understanding the developmental aetiology of risk.

Trop2 regulates motility and lamellipodia formation in cultured fetal lung fibroblasts

Proliferation and migration of fibroblasts are vital for fetal lung development. However, the regulatory mechanisms are poorly understood. We have previously shown that TROP2 gene expression is closely associated with fetal lung cell proliferation in vivo and that TROP2 knockdown decreases proliferation of fetal lung fibroblasts in culture. We hypothesized that the Trop2 protein also regulates the morphology and motility of fetal lung fibroblasts. Fibroblasts isolated from fetal rat lungs (gestational age embryonic day 19) adopted a myofibroblast-like morphology in culture. Trop2 protein was localized to lamellipodia. TROP2 siRNA significantly decreased: TROP2 mRNA levels by 77%, the proportion of cells containing Trop2 protein by 70%, and cell proliferation by 50%. TROP2 siRNA also decreased the degree of motility as determined by the number of gridlines that cells moved across (2.2 ± 0.2 vs. 3.2 ± 0.2; P < 0.001). TROP2 knockdown altered cell morphology, causing a notable absence of lamellipodia and abnormal localization of components of the cell migration apparatus, and it reduced phosphorylated ERK1 and ERK2 levels. In contrast, TROP2 overexpression significantly increased: TROP2 mRNA levels by 40-fold, cell proliferation by 40%, the proportion of cells that were motile by 20%, and the number of gridlines that cells moved across (2.1 ± 0.2 vs. 1.6 ± 0.1; P < 0.001). Our data suggest that Trop2 regulates cell proliferation and motility and that it does so by regulating the ERK pathway and several critical components of the cell migration apparatus.

cAMP response element binding protein1 is essential for activation of steroyl co-enzyme a desaturase 1 (Scd1) in mouse lung type II epithelial cells

Cyclic AMP Response Element-Binding Protein 1 (Creb1) is a transcription factor that mediates cyclic adenosine 3′, 5′-monophosphate (cAMP) signalling in many tissues. Creb1^−/− mice die at birth due to respiratory failure and previous genome-wide microarray analysis of E17.5 Creb1^−/− fetal mouse lung identified important Creb1-regulated gene targets during lung development. The lipogenic enzymes stearoyl-CoA desaturase 1 (Scd1) and fatty acid synthase (Fasn) showed highly reduced gene expression in Creb1^−/− lungs. We therefore hypothesized that Creb1 plays a crucial role in the transcriptional regulation of genes involved in pulmonary lipid biosynthetic pathways during lung development. In this study we confirmed that Scd1 and Fasn mRNA levels were down regulated in the E17.5 Creb1^−/− mouse lung while the lipogenic-associated transcription factors SrebpF1, C/ebpα and Pparγ were increased. In vivo studies using germline (Creb1^−/−) and lung epithelial-specific (Creb1^EpiΔ/Δ) Creb1 knockout mice showed strongly reduced Scd1, but not Fasn gene expression and protein levels in lung epithelial cells. In vitro studies using mouse MLE-15 epithelial cells showed that forskolin-mediated activation of Creb1 increased both Scd1 gene expression and protein synthesis. Additionally, MLE15 cells transfected with a dominant-negative ACreb vector blocked forskolin-mediated stimulation of Scd1 gene expression. Lipid profiling in MLE15 cells showed that dominant-negative ACreb suppressed forskolin-induced desaturation of ether linked lipids to produce plasmalogens, as well as levels of phosphatidylethanolamine, ceramide and lysophosphatidylcholine. Taken together these results demonstrate that Creb1 is essential for the induction and maintenance of Scd1 in developing fetal mouse lung epithelial cells.

Nfil3 is a glucocorticoid-regulated gene required for glucocorticoid-induced apoptosis in male murine T cells

Glucocorticoids (GCs) have essential roles in the regulation of development, integrated metabolism, and immune and neurological responses, and act primarily via the glucocorticoid receptor (GR). In most cells, GC treatment results in down-regulation of GR mRNA and protein levels via negative feedback mechanisms. However, in GC-treated thymocytes, GR protein levels are maintained at a high level, increasing sensitivity of thymocytes to GCs, resulting in apoptosis termed glucocorticoid-induced cell death (GICD). CD4(+)CD8(+) double-positive thymocytes and thymic natural killer T cells in particular are highly sensitive to GICD. Although GICD is exploited via the use of synthetic GC analogues in the treatment of hematopoietic malignancies, the intracellular molecular pathway of GICD is not well understood. To explore GICD in thymocytes, the authors performed whole genome expression microarray analysis in mouse GR exon 2 null vs wild-type thymus RNA 3 hours after dexamethasone treatment. Identified and validated direct GR targets included P21 and Bim, in addition to an important transcriptional regulator Nfil3, which previously has been associated with GICD and is essential for natural killer cell development in vivo. Immunostaining of NFIL3 in whole thymus localized NFIL3 primarily to the medullary region, and double labeling colocalized NFIL3 to apoptotic cells. In silico analysis revealed a putative GC response element 5 kb upstream of the Nfil3 promoter that is strongly conserved in the rat genome and was confirmed to bind GR by chromatin immunoprecipitation. The knockdown of Nfil3 mRNA levels to 20% of normal using specific small interfering RNAs abrogated GICD, indicating that NFIL3 is required for normal GICD in CTLL-2 T cells.

Extended international (IOTF) body mass index cut-offs for thinness, overweight and obesity

BACKGROUND

The international (International Obesity Task Force; IOTF) body mass index (BMI) cut-offs are widely used to assess the prevalence of child overweight, obesity and thinness. Based on data from six countries fitted by the LMS method, they link BMI values at 18 years (16, 17, 18.5, 25 and 30 kg m(-2)) to child centiles, which are averaged across the countries. Unlike other BMI references, e.g. the World Health Organization (WHO) standard, these cut-offs cannot be expressed as centiles (e.g. 85th).

METHODS

To address this, we averaged the previously unpublished L, M and S curves for the six countries, and used them to derive new cut-offs defined in terms of the centiles at 18 years corresponding to each BMI value. These new cut-offs were compared with the originals, and with the WHO standard and reference, by measuring their prevalence rates based on US and Chinese data.

RESULTS

The new cut-offs were virtually identical to the originals, giving prevalence rates differing by < 0.2% on average. The discrepancies were smaller for overweight and obesity than for thinness. The international and WHO prevalences were systematically different before/after age 5.

CONCLUSIONS

Defining the international cut-offs in terms of the underlying LMS curves has several benefits. New cut-offs are easy to derive (e.g. BMI 35 for morbid obesity), and they can be expressed as BMI centiles (e.g. boys obesity = 98.9th centile), allowing them to be compared with other BMI references. For WHO, median BMI is relatively low in early life and high at older ages, probably due to its method of construction.

The development of growth references and growth charts

CONTEXT

De Montbeillard produced the first growth chart in the late 18(th) century. Since then, growth assessment has developed to become an essential component of child health practice.

OBJECTIVE

To provide a brief history of (i) anthropometry, i.e. growth measurements; (ii) growth references, the statistical summary of anthropometry and (iii) growth charts, the visual representation of growth references for clinical use.

METHODS

The major contributors in the three categories over the past 200 years were identified and their historical contributions put in context with more recent developments.

RESULTS

Anthropometry was originally collected for administrative or public health purposes, its medical role emerging at the end of the 19(th) century. Growth reference data were collected in earnest from the 19(th) century, during which time the familiar statistical summary statistics-mean, SD, centiles-were developed. More advanced statistical methods emerged much later. Growth charts first appeared in the late 19(th) century and Tanner and Whitehouse later popularized the concepts of velocity and conditional references for growth in puberty. An important recent reference is the WHO growth standard, which documents optimal growth and has been adopted by many countries including the UK. Arising from it, the UK-WHO charts have pioneered many design features to improve usability and accuracy.

CONCLUSION

Growth charts have developed considerably in 200 years and they represent an impressive synthesis of anthropometry, statistical summary and chart design.

Medical, statistical, ethical and human rights considerations in the assessment of age in children and young people subject to immigration control

BACKGROUND

Unprecedented changes in both the scale and the complexity of international migration have led to international concern and controversy over the assessment of age in children and young people subject to immigration control or seeking asylum who say they are children yet have no documents to prove their stated age.

SOURCES OF DATA

The article reviews the existing evidence on the reliability of medical and non-medical techniques for the assessment of chronological age.

AREAS OF AGREEMENT

There is evidence that radiography (X-rays) of bones and teeth, which is increasingly relied upon by immigration authorities, is imprecise, unethical and potentially unlawful, and should not be used for age assessment.

AREAS OF CONTROVERSY

Medical techniques including X-rays continue to be relied upon in the absence of an alternative approach resulting in legal challenges and uncertainty for children and young people.

AREAS TIMELY FOR DEVELOPING RESEARCH

Further work is needed to establish a process for age assessment based on a 'holistic' multi-disciplinary approach which focuses not on chronological age exclusively but rather on the needs of children and young people subject to immigration control.

How good are BMI charts for monitoring children's attempts at obesity reduction?

INTRODUCTION

Body mass index (BMI) is the pragmatic measure to assess children's obesity clinically and BMI charts are widely used for counselling families about children's weight management over time.

AIMS

To explore the variability in clinicians' interpretation of BMI patterns and to ascertain the diagnostic accuracy of their judgement by relating it to change in body composition by dual-emission x-ray absorptiometry (DXA).

METHODS

Data from 70 children who participated in a trial of a weight management programme for obese children were analysed. BMI was plotted on UK 1990 charts at baseline, 6 months and 12 months, and four clinicians experienced in obesity management independently scored the charts on a five-point scale for how successful children were in tackling their obesity over a 6-month period. Scores were compared with change in BMI, fat mass and lean mass z-scores as measured by DXA.

RESULTS

54 children (aged 8-15 years; BMI z-score 2.93 (SD 0.48)) had simultaneous BMI and DXA scans performed, giving 104 pairs of measurements 6 months apart. There was good consistency between clinicians' scores for weight management and these related well to change in BMI and fat mass z-scores, but not lean mass z-score. They reported that measurement proximity to centile lines and crossing of lines influenced their confidence in making a decision and change in severe obesity was harder to judge as higher centile lines are so far apart.

CONCLUSIONS

BMI charts are useful for assessing children's attempts at weight management, and provide a reasonably accurate indication of change in body fat. Recommendations are made regarding BMI chart design and guidance in interpreting measurements.

The oncogene Trop2 regulates fetal lung cell proliferation

The factors regulating growth of the developing lung are poorly understood, although the degree of fetal lung expansion is critical. The oncogene Trop2 (trophoblast antigen 2) is upregulated during accelerated fetal lung growth, and we hypothesized that it may regulate normal fetal lung growth. We investigated Trop2 expression in the fetal and neonatal sheep lung during accelerated and delayed lung growth induced by alterations in fetal lung expansion, as well as in response to glucocorticoids. Trop2 expression was measured using real-time PCR and localized spatially using in situ hybridization and immunofluorescence. During normal lung development, Trop2 expression was higher at 90 days gestational age (GA; 4.0 ± 0.8) than at 128 days GA (1.0 ± 0.1), decreased to 0.5 ± 0.1 at 142 days GA (full term ∼147 days GA), and was positively correlated to lung cell proliferation rates (r = 0.953, P < 0.005). Trop2 expression was regulated by fetal lung expansion, but not by glucocorticoids. It was increased nearly threefold by 36 h of increased fetal lung expansion (P < 0.05) and was reduced to ∼55% of control levels by reduced fetal lung expansion (P < 0.05). Trop2 expression was associated with lung cell proliferation during normal and altered lung growth, and the TROP2 protein colocalized with Ki-67-positive cells in the fetal lung. TROP2 was predominantly localized to fibroblasts and type II alveolar epithelial cells. Trop2 small interfering RNA decreased Trop2 expression by ∼75% in cultured fetal rat lung fibroblasts and decreased their proliferation by ∼50%. Cell viability was not affected. This study demonstrates that TROP2 regulates lung cell proliferation during development.

Prevalence and persistence of sleep disordered breathing symptoms in young children: a 6-year population-based cohort study

STUDY OBJECTIVES

To describe the prevalence, persistence, and characteristics associated with sleep disordered breathing (SDB) symptoms in a population-based cohort followed from 6 months to 6.75 years.

DESIGN

Avon Longitudinal Study of Parents and Children (ALSPAC).

SETTING

England, 1991-1999.

PARTICIPANTS

12,447 children in ALSPAC with parental report of apnea, snoring, or mouth-breathing frequency on any one of 7 questionnaires.

MEASUREMENTS

Symptom prevalence rates-assessed as "Always" and "Habitually"-are reported at 0.5, 1.5, 2.5, 3.5, 4.75, 5.75, and 6.75 years of age. The proportion of children in whom symptoms develop, persist or abate between observation points is reported. Exploratory multivariate analyses identified SDB risk factors at 1.5, 4.75, and 6.75 years.

RESULTS

The prevalence of apnea ("Always") is 1%-2% at all ages assessed. In contrast, snoring "Always" ranges from 3.6% to 7.7%, and snoring "Habitually" ranges from 9.6% to 21.2%, with a notable increase from 1.5- 2.5 years. At 6 years old, 25% are habitual mouth-breathers. The "Always" and "Habitual" incidence of each symptom between time points is 1%-5% and 5%-10%, respectively. In multivariate analyses of combined symptoms, socioeconomic factors have stronger, more persistent effects upon increased SDB risk than gestational age, gender, or race (aside from 1.5 years); adenoidectomy decreases risk by 40%-50%.

CONCLUSIONS

This is the first natural history study of the primary symptoms of SDB across a key 6-year period in the development of SDB symptoms. Snoring rates are higher and spike earlier than previously reported. Symptoms are dynamic, suggesting the need for early and continued vigilance in early childhood.