Interactions between GH, IGF-I, glucocorticoids, and thyroid hormones during skeletal growth

Vitamin D in pituitary driven osteopathies

The evidence that pituitary hormones may bypass peripheral endocrine glands to exert remarkable effects on the skeleton is gaining ground. Both hormonal excess and deficit may determine impairment in bone structure, and they commonly result in bone loss in patients affected by pituitary and neuroendocrine disorders. Vertebral fractures are the most common skeletal alterations and may occur independently of bone mass. Use of vitamin D (VD) supplementation is still debated in this setting. This review will focus on the interactions between different metabolites of VD and pituitary hormones, and the effects of VD supplementation on bone metabolism in patients with pituitary diseases.

Mitochondrial function is enhanced by thyroid hormones during zebra finch development

An organism's response to its environment is largely determined by changes in the energy supplied by aerobic mitochondrial metabolism via adenosine triphosphate (ATP) production. ATP is especially important under energy-demanding conditions, such as during rapid growth. It is currently poorly understood how environmental factors influence energy metabolism and mitochondrial functioning, but recent studies suggest the role of thyroid hormones (TH). TH are key regulators of growth and metabolism and can be flexibly adjusted to environmental conditions, such as environmental temperature or food availability. To test whether TH enhancement is causally linked to mitochondrial function and growth, we provided TH orally at physiological concentrations during the main growth phase in zebra finch (Taeniopygia guttata) nestlings reared in a challenging environment. TH treatment accelerated maximal mitochondrial working capacity-a trait that reflects mitochondrial ATP production, without affecting growth. To our knowledge, this is the first study to characterize the regulation of mitochondria by TH during development in a semi-naturalistic context and to address implications for fitness-related traits, such as growth.

Slipped capital femoral epiphysis in an adolescent with congenital adrenal hyperplasia: A case report

In previous reports, hypothyroidism, hypopituitrism, and hypogonadism were common endocrine causes of SCFE, but this is the first time that congenital adrenal hyperplasia has been observed. As such, patients who have undergone long-term endocrine treatment for congenital adrenal hyperplasia could potentially be subjected to a higher risk for SCFE.

Thyroid hormone receptor Thra and Thrb knockout differentially affects osteoblast biology and thyroid hormone responsiveness in vitro

Thyroid hormones (TH) are important modulators of bone remodeling and thus, thyroid diseases, in particular hyperthyroidism, are able to compromise bone quality and fracture resistance. TH actions on bone are mediated by the thyroid hormone receptors (TR) TRα1 and TRβ1, encoded by Thra and Thrb, respectively. Skeletal phenotypes of mice lacking Thra (Thra0/0 ) and Thrb (Thrb-/- ) are well-described and suggest that TRα1 is the predominant mediator of TH actions in bone. Considering that bone cells might be affected by systemic TH changes seen in these mutant mice, here we investigated the effects of TR knockout on osteoblasts exclusively at the cellular level. Primary osteoblasts obtained from Thra0/0 , Thrb-/- , and respective wildtype (WT) mice were analyzed regarding their differentiation potential, activity and TH responsiveness in vitro. Thra, but not Thrb knockout promoted differentiation and activity of early, mature and late osteoblasts as compared to respective WT cells. Interestingly, while mineralization capacity and expression of osteoblast marker genes and TH target gene Klf9 was increased by TH in WT and Thra-deficient osteoblasts, Thrb knockout mitigated the responsiveness of osteoblasts to short (48 h) and long term (10 d) TH treatment. Further, we found a low ratio of Rankl, a potent osteoclast stimulator, over osteoprotegerin, an osteoclast inhibitor, in Thrb-deficient osteoblasts and in line, supernatants obtained from Thrb-/- osteoblasts reduced numbers of primary osteoclasts in vitro. In accordance to the increased Rankl/Opg ratio in TH-treated WT osteoblasts only, supernatants from these cells, but not from TH-treated Thrb-/- osteoblasts increased the expression of Trap and Ctsk in osteoclasts, suggesting that osteoclasts are indirectly stimulated by TH via TRβ1 in osteoblasts. In conclusion, our study shows that both Thra and Thrb differentially affect activity, differentiation and TH response of osteoblasts in vitro and emphasizes the importance of TRβ1 to mediate TH actions in bone.

Evaluation of catch-up growth in severe pediatric Hashimoto's hypothyroidism

BACKGROUND

We aimed to evaluate catch-up growth in children with severe Hashimoto's hypothyroidism (HH) after thyroid hormone replacement therapy (HRT).

METHODS

A multicenter retrospective study was conducted including children referred for growth slowdown that led to the diagnosis of HH between 1998 and 2017.

RESULTS

A total of 29 patients were included, with a median age of 9.7 years (13-172 months). Median height at diagnosis was -2.7 [-4.6; -0.1] standard deviation score (SDS), with a height loss of 2.5 [0.7; 5.4] SDS compared to height before growth deflection (p<0.0001). At diagnosis, the median TSH level was 819.5 mIU/L [100; 1844], the median FT4 level was 0 pmol/L [undetectable; 5.4], and the median anti-thyroperoxidase antibody level was 1601 UI/L [47; 25,500]. In the 20 patients treated only with HRT, there were significant differences between height at diagnosis and height at 1 year (n = 19, p<0.0001), 2 years (n = 13, p = 0.0005), 3 years (n = 9, p = 0.0039), 4 years (n = 10, p = 0.0078), and 5 years (n = 10, p = 0.0018) of treatment but not in the case of final height (n = 6, p = 0.0625). Median final height was -1.4 [-2.7; 1,5] SDS (n = 6), with a significant difference between height loss at diagnosis and total catch-up growth (p = 0.003). The other nine patients were also given growth hormone (GH). They were smaller at diagnosis (p = 0.01); however, there was no difference in final height between those two groups (p = 0.68).

CONCLUSION

Severe HH can lead to a major height deficit, and catch-up growth seems to be insufficient after treatment with HRT alone. In the most severe cases, administration of GH may enhance this catch-up.

Optimizing Growth: The Case for Iodine

Iodine is an essential micronutrient and component of thyroid hormone. An adequate dietary iodine intake is critical to maintain and promote normal growth and development, especially during vulnerable life stages such as pregnancy and early infancy. The role of iodine in cognitive development is supported by numerous interventional and observational studies, and when iodine intake is too low, somatic growth is also impaired. This can be clearly seen in cases of untreated congenital hypothyroidism related to severe iodine deficiency, which is characterized, in part, by a short stature. Nevertheless, the impact of a less severe iodine deficiency on growth, whether in utero or postnatal, is unclear. Robust studies examining the relationship between iodine and growth are rarely feasible, including the aspect of examining the effect of a single micronutrient on a process that is reliant on multiple nutrients for optimal success. Conversely, excessive iodine intake can affect thyroid function and the secretion of optimal thyroid hormone levels; however, whether this affects growth has not been examined. This narrative review outlines the mechanisms by which iodine contributes to the growth process from conception onwards, supported by evidence from human studies. It emphasizes the need for adequate iodine public health policies and their robust monitoring and surveillance, to ensure coverage for all population groups, particularly those at life stages vulnerable for growth. Finally, it summarizes the other micronutrients important to consider alongside iodine when seeking to assess the impact of iodine on somatic growth.

Sfrp4 expression in thyroxine treated calvarial cells

AIMS

Evidence suggests alterations of thyroid hormone levels can disrupt normal bone development. Most data suggest the major targets of thyroid hormones to be the Htra1/Igf1 pathway. Recent discovery by our group suggests involvement of targets WNT pathway, specifically overexpression of antagonist Sfrp4 in the presence of exogenous thyroid hormone.

MAIN METHODS

Here we aimed to model these interactions in vitro using primary and isotype cell lines to determine if thyroid hormone drives increased Sfrp4 expression in cells relevant to craniofacial development. Transcriptional profiling, bioinformatics interrogation, protein and function analyses were used.

KEY FINDINGS

Affymetrix transcriptional profiling found Sfrp4 overexpression in primary cranial suture derived cells stimulated with thyroxine in vitro. Interrogation of the SFRP4 promoter identified multiple putative binding sites for thyroid hormone receptors. Experimentation with several cell lines demonstrated that thyroxine treatment induced Sfrp4 expression, demonstrating that Sfrp4 mRNA and protein levels are not tightly coupled. Transcriptional and protein analyses demonstrate thyroid hormone receptor binding to the proximal promoter of the target gene Sfrp4 in murine calvarial pre-osteoblasts. Functional analysis after thyroxine hormone stimulation for alkaline phosphatase activity shows that pre-osteoblasts increase alkaline phosphatase activity compared to other cell types, suggesting cell type susceptibility. Finally, we added recombinant SFRP4 to pre-osteoblasts in combination with thyroxine treatment and observed a significant decrease in alkaline phosphatase positivity.

SIGNIFICANCE

Taken together, these results suggest SFRP4 may be a key regulatory molecule that prevents thyroxine driven osteogenesis. These data corroborate clinical findings indicating a potential for SFRP4 as a diagnostic or therapeutic target for hyperostotic craniofacial disorders.

Temperature, size and developmental plasticity in birds

As temperatures increase, there is growing evidence that species across much of the tree of life are getting smaller. These climate change-driven size reductions are often interpreted as a temporal analogue of the observation that individuals within a species tend to be smaller in the warmer parts of the species' range. For ectotherms, there has been a broad effort to understand the role of developmental plasticity in temperature-size relationships, but in endotherms, this mechanism has received relatively little attention in favour of selection-based explanations. We review the evidence for a role of developmental plasticity in warming-driven size reductions in birds and highlight insulin-like growth factors as a potential mechanism underlying plastic responses to temperature in endotherms. We find that, as with ectotherms, changes in temperature during development can result in shifts in body size in birds, with size reductions associated with warmer temperatures being the most frequent association. This suggests developmental plasticity may be an important, but largely overlooked, mechanism underlying warming-driven size reductions in endotherms. Plasticity and natural selection have very different constraining forces, thus understanding the mechanism linking temperature and body size in endotherms has broad implications for predicting future impacts of climate change on biodiversity.

TNF overexpression and dexamethasone treatment impair chondrogenesis and bone growth in an additive manner

Children with chronic inflammation are often treated with glucocorticoids (GCs) and many of them experience growth retardation. It is poorly understood how GCs interact with inflammatory cytokines causing growth failure as earlier experimental studies have been performed in healthy animals. To address this gap of knowledge, we used a transgenic mouse model where human TNF is overexpressed (huTNFTg) leading to chronic polyarthritis starting from the first week of age. Our results showed that femur bone length and growth plate height were significantly decreased in huTNFTg mice compared to wild type animals. In the growth plates of huTNFTg mice, increased apoptosis, suppressed Indian hedgehog, decreased hypertrophy, and disorganized chondrocyte columns were observed. Interestingly, the GC dexamethasone further impaired bone growth, accelerated chondrocyte apoptosis and reduced the number of chondrocyte columns in huTNFTg mice. We conclude that TNF and dexamethasone separately suppress chondrogenesis and bone growth when studied in an animal model of chronic inflammation. Our data give a possible mechanistic explanation to the commonly observed growth retardation in children with chronic inflammatory diseases treated with GCs.

Endocrine Disorders in Children with Brain Tumors: At Diagnosis, after Surgery, Radiotherapy and Chemotherapy

INTRODUCTION

Brain tumors are the second most frequent type of all pediatric malignancies. Depending on their localization, patients with brain tumors may present neurological or ophthalmological symptoms, but also weight anomalies and endocrine disorders ranging from growth hormone deficiency, anomalies of puberty, diabetes insipidus to panhypopituitarism. Immediately at diagnosis, all patients with brain tumors require a complete assessment of the hypothalamic-pituitary function in order to address eventual endocrine disorders. Moreover, children and adolescents undergoing brain surgery must receive peri- and postoperative hydrocortisone stress therapy. Post-operative disorders of water homeostasis are frequent, ranging from transient diabetes insipidus, as well as syndrome of inappropriate antidiuretic hormone secretion to persistent diabetes insipidus. Late endocrine disorders may result from surgery near or within the hypothalamic-pituitary region. Pituitary deficits are frequent after radiotherapy, especially growth hormone deficiency. Thyroid nodules or secondary thyroid cancers may arise years after radiotherapy. Gonadal dysfunction is frequent after chemotherapy especially with alkylating agents.

CONCLUSION

Early detection and treatment of specific endocrine disorders at diagnosis, perioperatively, and during long-term follow-up result in improved general and metabolic health and quality of life.

Metformin alleviates the dysregulated testicular steroidogenesis and spermatogenesis induced by carbimazole in levothyroxine-primed rats

Most of the published experiments about carbimazole (CMZ)-induced testicular injury are constructed in normal healthy animals, which lakes the translational identification. Despite metformin (MET) having advantageous effects on injured testicles, its impact on thyroid function is arguable. In the current levothyroxine (LT4)/CMZ model, Wistar rats were primed by LT4 for sixty days. CMZ was then given individually or simultaneously with different doses of MET, 100, 200, and 400 mg, daily for thirty days. Serum was assessed for thyroid profile panel, sex hormones, and gonadotropin levels. Testicular tissues were examined for steroidogenesis, spermatogenesis, inflammation, and apoptosis. Histopathology of thyroid and testes were examined, besides thyroidal nuclear factor (NF)-kB expression. MET in a dose-response manner improved the LT4/CMZ-induced testicular toxicity by increasing the steroidogenic acute regulatory protein (StAR), and 17-β-hydroxysteroid dehydrogenase (17βHSD) activities, the proliferating cell nuclear antigen (PCNA), sperm count and motility, sex hormones, and gonadotropin levels. MET-400 mg markedly decreased the elevated NF-kB expressions, tumour necrosis factor (TNF)-α, caspase-3, and BAX, and increased BCL-2. LT4/CMZ could be used as translational animal modelling. MET displayed a dose-dependent ameliorative effect on the LT4/CMZ model without significant harmful effects on thyroid functions. MET-testicular protective roles in diabetics with thyroidal diseases should be explored.

Transcriptomic Profiling Revealed Signaling Pathways Associated with the Spawning of Female Zebrafish under Cold Stress

As one of the critical abiotic factors, temperature controls fish development and reproduction. However, the effects of low temperature on the transcriptional regulation of zebrafish reproduction remain largely unclear. In this study, the fecundity of zebrafish was examined after exposure to cold temperatures at 19.5 °C, 19 °C, 18.5 °C, or 18 °C. The temperature at 19 °C showed no significant influence on the fecundity of zebrafish, but temperature at 18.5 °C or 18 °C significantly blocked the spawning of females, suggesting the existence of a low temperature critical point for the spawning of zebrafish females. Based on these observations, the brains of anesthetized fish under cold stress at different cold temperatures were collected for high-throughput RNA-seq assays. Key genes, hub pathways and important biological processes responding to cold temperatures during the spawning of zebrafish were identified through bioinformatic analysis. The number of down-regulated and up-regulated genes during the temperature reduction from egg-spawning temperatures at 19.5 °C and 19 °C to non-spawning temperatures at 18.5 °C and 18 °C were 2588 and 2527 (fold change ≥ 1.5 and p-value ≤ 0.01), respectively. Venn analysis was performed to identify up- and down-regulated key genes. KEGG enrichment analysis indicated that the hub pathways overrepresented among down-regulated key genes included the GnRH signaling pathway, vascular smooth muscle contraction, C-type lectin receptor signaling pathway, phosphatidylinositol signaling system and insulin signaling pathway. GO enrichment analysis of down-regulated key genes revealed the most important biological processes inhibited under non-spawning temperatures at 18.5 °C and 18 °C were photoreceptor cell outer segment organization, circadian regulation of gene expression and photoreceptor cell maintenance. Furthermore, 99 hormone-related genes were found in the brain tissues of non-spawning and spawning groups, and GnRH signaling pathway and insulin signaling pathway were enriched from down-regulated genes related to hormones at 18.5 °C and 18 °C. Thus, these findings uncovered crucial hormone-related genes and signaling pathways controlling the spawning of female zebrafish under cold stress.

Risk Factors from Pregnancy to Adulthood in Multiple Sclerosis Outcome

Multiple sclerosis (MS) is an autoimmune disease characterized by a robust inflammatory response against myelin sheath antigens, which causes astrocyte and microglial activation and demyelination of the central nervous system (CNS). Multiple genetic predispositions and environmental factors are known to influence the immune response in autoimmune diseases, such as MS, and in the experimental autoimmune encephalomyelitis (EAE) model. Although the predisposition to suffer from MS seems to be a multifactorial process, a highly sensitive period is pregnancy due to factors that alter the development and differentiation of the CNS and the immune system, which increases the offspring’s susceptibility to develop MS. In this regard, there is evidence that thyroid hormone deficiency during gestation, such as hypothyroidism or hypothyroxinemia, may increase susceptibility to autoimmune diseases such as MS. In this review, we discuss the relevance of the gestational period for the development of MS in adulthood.

Thyroid metabolism and supplementation. A review framed in sports environment

OBJECTIVES

This paper aimed to consider those features that may suggest a link between thyroid hormones pharmacology and athletes' health based on current consumption trends in a population of athletes.

METHODS

Methods used were observation, description, and synthesis, mainly. Among the documents reviewed were: books, scientific articles, and review articles peer-reviewed. The review covered sources published in the period 1961 to 2021. Only references with a traceable origin were accepted (DOI numbering, ISSN and ISBN, as well as peer-reviewed journals). The data on the consumption of thyroid hormones derivatives were extracted from the Doping Control Forms of athlete samples received at Laboratorio Antidoping FMSI of Rome from 2017 to 2021.

RESULTS

An overview of the biosynthesis, pharmacology, and metabolism of thyroid hormones, including thyronamines and thyronacetic acids, was presented. Likewise, a summary is presented on the relationship between thyroid hormones and ethnic and gender differences, their physiology in sport, and the reasons why their use could be considered attractive for athletes.

CONCLUSION

Today, thyroid hormones are not listed as a prohibited substance by the World Anti-Doping Agency. However, several requests to include levothyroxine on the prohibited list are documented. The observation that the number of athletes taking thyroid hormones is growing, particularly in sports such as cycling, triathlons, and skating, should prompt an update on this topic.

Profiling steroid and thyroid hormones with hair analysis in a cohort of women aged 25 to 45 years old

OBJECTIVE

Endogenous hormones regulate numerous physiological processes in humans. Some of them are routinely measured in blood, saliva and/or urine for the diagnosis of disorders. The analysis of fluids may, however, require multiple samples collected at different time points to avoid the high variability in the concentration of some hormones. In contrast, hair analysis has been proposed as an interesting alternative to reveal average hormone levels over a longer period. In this work, we developed and validated an analytical method for analyzing 36 endogenous steroid and thyroid hormones and one pineal hormone in human hair using ultra-performance liquid chromatography (UPLC)-tandem mass spectrometry (MS/MS).

METHODS

Sample preparation involved hair decontamination, pulverization, methanol extraction, and purification with C18-solid phase extraction. Extracts were then divided into two portions, respectively injected into an UPLC-MS/MS system, and analyzed using two different instrumental methods. The method was applied to a healthy female population aged 25-45 years.

RESULTS

The method was validated on supplemented hair samples for the 37 targeted hormones, and its application to the population under study allowed to detect 32 compounds in 2-100% of the samples. Complete reference intervals (2.5-97.5th percentiles) were established for estrone, 17β-estradiol, androstenedione, dehydroepiandrosterone, progesterone, 17α-hydroxyprogesterone, cortisone, cortisol and 3,3',5-triiodo-L-thyronine. Hair cortisone, cortisol, tetrahydrocortisone and tetrahydrocortisol concentrations were highly correlated with each other, with Kendall's τ correlation coefficients ranging from 0.52 to 0.68.

CONCLUSION

Allowing the detection of 32 hormones from different chemical classes, the present method will allow to broaden hormonal profiling for better identifying endocrine disorders.

Decreased Thyroxine Levels during rhGH Therapy in Children with Growth Hormone Deficiency

Background: Hypothyroidism in children leads to growth retardation. However, there is some evidence that recombinant human growth hormone (rhGH) therapy could suppress thyroid function. The most common observation in rhGH-treated patients is a decrease in thyroxine levels, which is reported as transient, but the studies in the field are inconsistent. We aimed to evaluate thyroid function in initially euthyroid children with idiopathic isolated GH deficiency during long-term rhGH therapy and to determine who is at a higher risk of thyroid function alterations during the therapy. Methods: The study group consisted of 101 children treated with rhGH for at least three years. Serum TSH and fT4 levels were determined at baseline, after the first six months and after each full year of therapy. The associations between changes in thyroid hormone levels during rhGH therapy and GH deficit, insulin-like growth factor-1 levels and growth response were investigated. Results: A significant decrease in fT4 levels (p = 0.01) was found as early as after the first six months of rhGH therapy. This effect persisted in the subsequent years of treatment without any significant changes in TSH values and tended to be rhGH dose related. Children with a greater fT4 decrease after the initiation of rhGH therapy were older, had higher bone age and responded to that therapy worse than children with lower fT4 changes. Conclusions: Our study revealed a long-term decrease in fT4 levels during rhGH therapy in initially euthyroid GHD children. The decrease in fT4 levels was associated with a lower growth response to rhGH therapy.

Intrauterine endogenous high glucocorticoids program ovarian dysfunction in female offspring secondary to prenatal caffeine exposure

Ovarian dysfunction has an intrauterine origin, and prenatal caffeine exposure (PCE) could lead to abnormal follicle counts in offspring after birth. However, the effect of PCE on offspring ovarian function and its mechanism of intrauterine programming have not been reported thus far. In this study, pregnant Wistar rats were intragastrically administered caffeine (30 and 120 mg/kg·d) at gestational days 9-20 (GD9-20). Certain tests were performed on the blood, ovaries and hypothalamus of female offspring at different time points. PCE female offspring had ovarian dysfunction in adulthood compared with the control. Further results showed that in utero ovarian morphological development and estradiol synthesis were inhibited but rapidly increased during puberty in the PCE group. The histone 3 lysine 27 acetylation (H3K27ac) level of the insulin-like growth factor 1 (IGF1) promoter region and its expression were decreased in the ovary, which was due to exposure to high levels of fetal blood corticosterone, and the H3K27ac level of IGF1 and its expression shifted to increase after birth with a decrease in serum corticosterone levels. Chronic stress led to increased serum corticosterone levels in adult offspring, whereas ovarian morphological development, the H3K27ac level of IGF1 and its expression, and estradiol synthesis were significantly inhibited. Moreover, the activity of the hypothalamic-pituitary-ovarian (HPO) axis was increased in the early postnatal period of PCE offspring, and chronic stress reversed these changes. In the KGN cell line, it was found that cortisol could promote the translocation of the glucocorticoid receptor (GR) into the nucleus and upregulate histone deacetylase 10 (HDAC10) to inhibit the H3K27ac level of IGF1 and its expression and estradiol synthesis. In summary, PCE is associated with ovarian dysfunction in female adult offspring, and the potential mechanism is related to intrauterine high glucocorticoid exposure by activating the GR and recruiting HDAC10 to affect ovarian glucocorticoid-IGF1 axis programming and to inhibit estradiol synthesis.

Transcriptome and Methylome Analysis Reveal Complex Cross-Talks between Thyroid Hormone and Glucocorticoid Signaling at Xenopus Metamorphosis

Background: Most work in endocrinology focus on the action of a single hormone, and very little on the cross-talks between two hormones. Here we characterize the nature of interactions between thyroid hormone and glucocorticoid signaling during Xenopus tropicalis metamorphosis. Methods: We used functional genomics to derive genome wide profiles of methylated DNA and measured changes of gene expression after hormonal treatments of a highly responsive tissue, tailfin. Clustering classified the data into four types of biological responses, and biological networks were modeled by system biology. Results: We found that gene expression is mostly regulated by either T₃ or CORT, or their additive effect when they both regulate the same genes. A small but non-negligible fraction of genes (12%) displayed non-trivial regulations indicative of complex interactions between the signaling pathways. Strikingly, DNA methylation changes display the opposite and are dominated by cross-talks. Conclusion: Cross-talks between thyroid hormones and glucocorticoids are more complex than initially envisioned and are not limited to the simple addition of their individual effects, a statement that can be summarized with the pseudo-equation: TH ∙ GC > TH + GC. DNA methylation changes are highly dynamic and buffered from genome expression.

Regulation of GH and GH Signaling by Nutrients

Growth hormone (GH) and insulin-like growth factor-1 (IGF-I) are pleiotropic hormones with important roles in lifespan. They promote growth, anabolic actions, and body maintenance, and in conditions of energy deprivation, favor catabolic feedback mechanisms switching from carbohydrate oxidation to lipolysis, with the aim to preserve protein storages and survival. IGF-I/insulin signaling was also the first one identified in the regulation of lifespan in relation to the nutrient-sensing. Indeed, nutrients are crucial modifiers of the GH/IGF-I axis, and these hormones also regulate the complex orchestration of utilization of nutrients in cell and tissues. The aim of this review is to summarize current knowledge on the reciprocal feedback among the GH/IGF-I axis, macro and micronutrients, and dietary regimens, including caloric restriction. Expanding the depth of information on this topic could open perspectives in nutrition management, prevention, and treatment of GH/IGF-I deficiency or excess during life.

Growth hormone replacement may influence the biological action of thyroid hormone on liver and bone tissue

OBJECTIVE

Growth hormone (GH) replacement alters the peripheral interconversion of thyroxine (T4) and triiodothyronine (T3). However, little is known about the clinical impact of these alterations. We aimed to compare changes observed in the serum T3:T4 ratio with known biological markers of thyroid hormone action derived from different peripheral tissues.

DESIGN

We prospectively studied twenty GH deficient men before and after GH replacement in a tertiary referral endocrine center. Serum biochemical measurements included insulin like growth factor-1 (IGF-1), thyroid hormones (free & total T3, free & total T4 and reverse T3) and TSH. Changes in thyroid hormone concentration were compared to alterations in hepatic and bone biomarkers of thyroid hormone action.

RESULTS

GH replacement provoked a decline in serum free T4 concentration (-1.09 ± 1.99 pmol/L; p = 0.02) and an increase in free T3 (+0.34 ± 0.15 pmol/L; p = 0.03); therefore, the free T3:free T4 ratio increased from 0.40 ± 0.02 to 0.47 ± 0.02 (p = 0.002). Sex hormone binding globulin (SHBG) level was unchanged. However, a decline in serum ferritin (-26.6 ± 8.5 ng/mL; p = 0.005) correlated with a fall in freeT4. Alterations in lipid profile, including a rise in large HDL sub-fractions and Lp (a) (+2.1 ± 21.1 nmol/L; p = 0.002) did not correlate with thyroid hormone levels. Significant increases were recorded in serum bone turnover markers - procollagen type 1 amino-terminal propeptide +57.4%; p = 0.0009, osteocalcin +48.6%; p = 0.0007; c-terminal telopeptides of type 1 collagen +73.7%; p = 0.002. Changes in bone formation markers occurred in parallel with fluctuations in thyroid hormone.

CONCLUSION

GH-induced alterations in the thyroid axis are associated with complex, tissue specific effects on thyroid hormone action. Modulation of bone turnover markers suggests that GH may improve the biological action of thyroid hormone on bone.

Investigating the effect of nitrate on juvenile turbot (Scophthalmus maximus) growth performance, health status, and endocrine function in marine recirculation aquaculture systems

Nitrate (NO₃^-), a potential toxic nitrogenous compound to aquatic animals, is distributed in aquatic ecosystems worldwide. The aim of this study was to investigate the effects of different NO₃^- levels on growth performance, health status, and endocrine function of juvenile turbot (Scophthalmus maximus) in recirculating aquaculture systems (RAS). Fish were exposed to 0 mg/L (control, CK), 50 mg/L (low nitrate, LN), 200 mg/L (medium nitrate, MN), and 400 mg/L (high nitrate, HN) NO₃-N for 60 d in experimental RAS. Cumulative survival (CS) was significantly decreased with increasing NO₃^- levels in LN, MN, and HN. The lowest CS was 35% in the HN group. Growth parameters, including absolute growth rate, specific growth rate, and feed conversion rate, were significantly different in HN compared with that in the CK. Histological survey of gills and liver revealed dose-dependent histopathological damage induced by NO₃^- exposure and significant differences in glutamate pyruvate transaminase and glutamate oxalate transaminase in MN and HN compared with that in the CK. The hepatosomatic index in HN was significantly higher than that in the CK. Additionally, NO₃^- significantly increased bioaccumulation in plasma in LN, MN, and HN compared to that in the CK. Significant decreases in hemoglobin and increases in methemoglobin levels indicated reduced oxygen-carrying capacity in HN. Additionally, qRT-PCR and enzyme-linked immunosorbent assay (ELISA) were developed to investigate key biomarkers involved in the GH/IGF-1, HPT, and HPI axes. Compared with that in the CK, the abundance of GH, GHRb, and IGF-1 was significantly lower in HN, whereas GHRa did not differ between treatments. The plasma T₃ level significantly decreased in LN, MN, and HN and T₄ significantly decreased in HN. The CRH, ACTH, and plasma cortisol levels were significantly upregulated in HN compared with that in the CK. We conclude that elevated NO₃^- exposure leads to growth retardation, impaired health status, and endocrine disorders in turbot and the NO₃^- level for juvenile turbot culture should not exceed 50 mg/L NO₃-N in RAS. Our findings indicate that endocrine dysfunction of the GH/IGF-1, HPT, and HPI axes might be responsible for growth inhibition induced by NO₃^- exposure.

Mass spectrometry-based proteomics analyses of post-translational modifications and proteoforms in human pituitary adenomas

Pituitary adenoma (PA) is a common intracranial neoplasm, which affects the hypothalamus-pituitary-target organ axis systems, and is hazardous to human health. Post-translational modifications (PTMs), including phosphorylation, ubiquitination, nitration, and sumoylation, are vitally important in the PA pathogenesis. The large-scale analysis of PTMs could provide a global view of molecular mechanisms for PA. Proteoforms, which are used to define various protein structural and functional forms originated from the same gene, are the future direction of proteomics research. The global studies of different proteoforms and PTMs of hypophyseal hormones such as growth hormone (GH) and prolactin (PRL) and the proportion change of different GH proteoforms or PRL proteoforms in human pituitary tissue could provide new insights into the clinical value of pituitary hormones in PAs. Multiple quantitative proteomics methods, including mass spectrometry (MS)-based label-free and stable isotope-labeled strategies in combination with different PTM-peptide enrichment methods such as TiO₂ enrichment of tryptic phosphopeptides and antibody enrichment of other PTM-peptides increase the feasibility for researchers to study PA proteomes. This article reviews the research status of PTMs and proteoforms in PAs, including the enrichment method, technical limitation, quantitative proteomics strategies, and the future perspectives, to achieve the goals of in-depth understanding its molecular pathogenesis, and discovering effective biomarkers and clinical therapeutic targets for predictive, preventive, and personalized treatment of PA patients.

Insulin-like growth factor 1 of wild vertebrates in a life-history context

Broad variation in intra- and interspecific life-history traits is largely shaped by resource limitation and the ensuing allocation trade-offs that animals are forced to make. Insulin-like growth factor 1 (IGF-1), a growth-hormone-dependent peptide, may be a key player in the regulation of allocation processes. In laboratory animals, the effects of IGF-1 on growth- and development (positive), reproduction (positive), and longevity (negative) are well established. We here review the evidence on these effects in wild vertebrates, where animals are more likely to face resource limitation and other challenges. We point out the similarities and dissimilarities in patterns of IGF-1 functions obtained in these two different study settings and discuss the knowledge we need to develop a comprehensive picture of the role of IGF-1 in mediating life-history variation of wild vertebrates.

Iodine status of pregnant women with obesity from inner city populations in the United Kingdom

BACKGROUND/OBJECTIVES

Iodine is essential for foetal neurodevelopment and growth. Requirements increase in pregnancy to support increased thyroid hormone synthesis for maternal and foetal requirements, and for foetal transfer. Iodine deficiency in pregnancy is widely reported, and obesity has been associated with sub-optimal thyroid function. We evaluated iodine status and its relation with birthweight in a secondary analysis of pregnant women with obesity from multi-ethnic inner-city settings who participated in the UK Pregnancies Better Eating and Activity trial (UPBEAT).

SUBJECTS/METHODS

Iodine and creatinine concentrations were evaluated in spot urine samples in the second (15⁺⁰-18⁺⁶ weeks, n = 954) trimester of pregnancy. We assessed iodine status as urinary iodine concentration (UIC) and urinary iodine-to-creatinine ratio (UI/Cr) and applied WHO/UNICEF/IGN population threshold of median UIC > 150 µg/L for iodine sufficiency. Relationships between iodine status and birthweight were determined using linear and logistic regression with appropriate adjustment, including for maternal BMI and gestational age.

RESULTS

Median (IQR) UIC and UI/Cr in the second trimester of pregnancy were 147 µg/L (99-257) and 97 µg/g (59-165), respectively. An UI/Cr <150 μg/g was observed in 70% of women. Compared to women with UI/Cr >150 µg/g, there was a trend for women with UI/Cr <150 µg/g to deliver infants with a lower birthweight (β = -60.0 g; 95% CI -120.9 to -1.01, P = 0.05).

CONCLUSIONS

Iodine status of pregnant women with obesity from this cohort of UK women was suboptimal. Lower iodine status was associated with lower birthweight.

Characterization of phthalate exposure in relation to serum thyroid and growth hormones, and estimated daily intake levels in children exposed to phthalate-tainted products: A longitudinal cohort study

BACKGROUND

No information is available on the long-term effects on thyroid and growth hormones of children exposed to phthalate-tainted products, despite the infamous 2011 Taiwan phthalate episode. We investigated estimated daily intake levels and their long-term effects on serum thyroid and growth hormone levels in children.

METHODS

We recruited 166 children (2-18 years old) in three visits who provided specimens and filled out a questionnaire from the Risk Assessment of Phthalate Incident in Taiwan (RAPIT) project study from 2012 to 2016. Morning spot urine samples were analyzed for nine phthalate metabolites. Serum thyroid (triiodothyronine [T₃], thyroxine [T₄], and free T₄) and growth hormone (insulin-like growth factor-1 [IGF-1] and its binding protein 3 [IGF-BP3]) levels were measured. A generalized estimating equation model was used to evaluate associations between phthalate metabolite levels and children's thyroid and growth hormone levels.

RESULTS

The median metabolite levels of monomethyl phthalate (MMP), Σdibutyl phthalate (DBP), and Σdi-(2-ethylhexyl) phthalate (DEHP) at visits 1, 2, and 3 were 6.59, 10.5, and 21.0 ng/mL, 0.15, 0.24, and 0.20 nmol/mL, and 0.15, 0.17, and 0.12 nmol/mL, respectively. After adjusting for potential confounding factors, we found that levels of urinary MMP were negatively associated with T₃ (β = -0.013, p = 0.047), T₄ (β = -0.016, p = 0.006), free T₄ (β = -0.012, p = 0.002), and IGF-BP3 (β = -0.025, p = 0.003). Urinary mono-ethyl phthalate (MEP) was negatively associated with IGF-1 (β = -0.027, p = 0.029) and IGF-BP3 (β = -0.016, p = 0.018). In addition, serum free T₄ was positively associated with urinary mono-2-ethyl-5-hydroxy hexyl phthalate (MEHHP) (β = 0.016, p = 0.043), mono-2-ethyl-5-oxohexyl phthalate (MEOHP) (β = 0.015, p = 0.024), and ΣDEHPm (β = 0.019, p = 0.020).

CONCLUSIONS

Our findings support the hypothesis that specific phthalates disturb the hemostasis of thyroid and growth hormone levels in children exposed to phthalate-tainted products.

Tall stature in children and adolescents

Tall stature is usually defined as a height beyond 97^th percentile or more than 2 SD above the mean height for age and sex in a defined population. Familiar tall stature, also known as constitutional tall stature, is the most common cause of tall stature. Overnutrition, obesity, also usually causes overgrowth. Tall stature by itself is not a pathological condition, however, there are a number of disorders associated with tall stature. Some genetic disorders and syndromes may be associated with mental retardation and various complications. Therefore, recognition of tall stature and revealing the underlying pathogenic causes and making the diagnosis are important not to miss the serious conditions and to provide adequate medical care and genetic counseling. Pathological causes for tall statute include endocrine disorders, such as excessive growth hormone secretion, hyperthyroidism, precocious puberty and lipodystrophy, chromosome disorders, such as Trisomy X (47, XXX female), Klinefelter Syndrome (47, XXY), XYY syndrome (47, XYY male) and fragile X syndrome, and syndromes and metabolic disorders, such as Marfan Syndrome, Beckwith-Wiedemann Syndrome, Simpson-Golabi-Behmel Syndrome, Sotos Syndrome and homocystinuria. Children may require growth-reductive treatment if the predicted adult height would be excessive and unacceptable. Some hormonal, high doses of sex steroids, or surgical, bilateral percutaneous epiphysiodesis of the distal femur and proximal tibia and fibula, treatment is currently available to reduce adult height.

An Alport syndrome boy with Van Wyk-Grumbach syndrome induced by prolonged untreated congenital hypothyroidism

Alport syndrome (AS) is a rare genetic disorder that causes progressive nephritis and is more common among males. Studies have reported an association between thyroid antibodies and hypothyroidism in patients with AS, but the relevance of this relationship is under debate. Prolonged untreated hypothyroidism induces short stature, abnormal pubertal development, and various other symptoms. However, children with long-standing hypothyroidism rarely present with signs of precocious puberty, or Van Wyk-Grumbach syndrome (VWGS). We report the case of a boy, 8 years and 4 months old, who had VWGS caused by prolonged untreated congenital hypothyroidism and AS. The boy had repeated gross hematuria and proteinuria and was diagnosed with AS by renal biopsy and genetic testing. He had normal renal function but severe growth retardation and hypothyroidism. Obesity, bone age delay, hyperlipidemia, and abnormal increased testicle size were also present due to prolonged untreated hypothyroidism. His thyroid antibody titer elevation was unclear, although ultrasonography and thyroid scanning showed a decrease in thyroid volume. We diagnosed the patient with congenital hypothyroidism caused by thyroid dysgenesis. VWGS was diagnosed due to hypothyroidism, delayed bone age, and pseudoprecocious puberty. To the best of our knowledge, this is the first report of a prepubertal Korean boy with prolonged untreated congenital hypothyroidism complicated by VWGS in AS.

Effects of eggshell temperature pattern during incubation on tibia characteristics of broiler chickens at slaughter age

This study was designed to determine effects of eggshell temperature (EST) pattern in week 2 and week 3 of incubation on tibia development of broiler chickens at slaughter age. A total of 468 Ross 308 eggs were incubated at an EST of 37.8°C from incubation day (E) 0 to E7. Thereafter, a 2 × 2 factorial arrangement with 2 EST (37.8°C and 38.9°C) from E8 to E14 and 2 EST (36.7°C and 37.8°C) from E15 till hatch was applied. After hatching, chickens were reared until slaughter age with the 4 EST treatments and 8 replicates per treatment. At day 41 and 42, one male chicken per replicate per day was selected, and hock burn and food pad dermatitis were scored. Rotated tibia, tibia dyschondroplasia, epiphyseal plate abnormalities, bacterial chondronecrosis with osteomyelitis, and epiphysiolysis were assessed. Tibia weight, length, thickness, head thickness, and robusticity index were determined. X-ray analyses (osseous volume, pore volume, total volume, volume fraction, mineral content, and mineral density) and a 3-point bending test (ultimate strength, yield strength, stiffness, energy to fracture, and elastic modulus) were performed. A high EST (38.9°C) in week 2 of incubation, followed by a normal EST (37.8°C) in week 3 resulted in higher mineral content (P = 0.001), mineral density (P = 0.002), ultimate strength (P = 0.04), yield strength (P = 0.03), and stiffness (P = 0.05) compared with the other 3 EST groups (week 2 × week 3 interaction). A high EST (38.9°C) in week 2 of incubation, regardless of the EST in week 3, resulted in a higher tibia weight (P < 0.001), thickness (P = 0.05), osseous volume (P < 0.001), and total volume (P < 0.001) than a normal EST (37.8°C). It can be concluded that 1.1°C higher EST than normal in week 2 of incubation appears to stimulate tibia morphological, biophysical, and mechanical characteristics of broiler chickens at slaughter age. Additionally, a 1.1°C lower EST in week 3 of incubation appears to have negative effects on tibia characteristics, particularly in interaction with the EST in week 2 of incubation.

Hormones as adaptive control systems in juvenile fish

Growth is an important theme in biology. Physiologists often relate growth rates to hormonal control of essential processes. Ecologists often study growth as a function of gradients or combinations of environmental factors. Fewer studies have investigated the combined effects of environmental and hormonal control on growth. Here, we present an evolutionary optimization model of fish growth that combines internal regulation of growth by hormone levels with the external influence of food availability and predation risk. The model finds a dynamic hormone profile that optimizes fish growth and survival up to 30 cm, and we use the probability of reaching this milestone as a proxy for fitness. The complex web of interrelated hormones and other signalling molecules is simplified to three functions represented by growth hormone, thyroid hormone and orexin. By studying a range from poor to rich environments, we find that the level of food availability in the environment results in different evolutionarily optimal strategies of hormone levels. With more food available, higher levels of hormones are optimal, resulting in higher food intake, standard metabolism and growth. By using this fitness-based approach we also find a consequence of evolutionary optimization of survival on optimal hormone use. Where foraging is risky, the thyroid hormone can be used strategically to increase metabolic potential and the chance of escaping from predators. By comparing model results to empirical observations, many mechanisms can be recognized, for instance a change in pace-of-life due to resource availability, and reduced emphasis on reserves in more stable environments.This article has an associated First Person interview with the first author of the paper.

Effects of lighting schedule during incubation of broiler chicken embryos on leg bone development at hatch and related physiological characteristics

Providing a broiler chicken embryo with a lighting schedule during incubation may stimulate leg bone development. Bone development may be stimulated through melatonin, a hormone released in darkness that stimulates bone development, or increased activity in embryos exposed to a light-dark rhythm. Aim was to investigate lighting conditions during incubation and leg bone development in broiler embryos, and to reveal the involved mechanisms. Embryos were incubated under continuous cool white 500 lux LED light (24L), continuous darkness (24D), or 16h of light, followed by 8h of darkness (16L:8D) from the start of incubation until hatching. Embryonic bone development largely takes place through cartilage formation (of which collagen is an important component) and ossification. Expression of genes involved in cartilage formation (col1α2, col2α1, and col10α1) and ossification (spp1, sparc, bglap, and alpl) in the tibia on embryonic day (ED)13, ED17, and at hatching were measured through qPCR. Femur and tibia dimensions were determined at hatch. Plasma growth hormone and corticosterone and pineal melatonin concentrations were determined every 4h between ED18.75 and ED19.5. Embryonic heart rate was measured twice daily from ED12 till ED19 as a reflection of activity. No difference between lighting treatments on gene expression was found. 24D resulted in higher femur length and higher femur and tibia weight, width, and depth at hatch than 16L:8D. 24D furthermore resulted in higher femur length and width and tibia depth than 24L. Embryonic heart rate was higher for 24D and 16L:8D in both its light and dark period than for 24L, suggesting that 24L embryos may have been less active. Melatonin and growth hormone showed different release patterns between treatments, but the biological significance was hard to interpret. To conclude, 24D resulted in larger leg bones at hatch than light during incubation, but the underlying pathways were not clear from present data.

Coordinated transcriptional regulation by thyroid hormone and glucocorticoid interaction in adult mouse hippocampus-derived neuronal cells

The hippocampus is a well-known target of thyroid hormone (TH; e.g., 3,5,3’-triiodothyronine—T₃) and glucocorticoid (GC; e.g., corticosterone—CORT) action. Despite evidence that TH and GC play critical roles in neural development and function, few studies have identified genes and patterns of gene regulation influenced by the interaction of these hormones at a genome-wide scale. In this study we investigated gene regulation by T₃, CORT, and T₃ + CORT in the mouse hippocampus-derived cell line HT-22. We treated cells with T₃, CORT, or T₃ + CORT for 4 hr before cell harvest and RNA isolation for microarray analysis. We identified 9 genes regulated by T₃, 432 genes by CORT, and 412 genes by T₃ + CORT. Among the 432 CORT-regulated genes, there were 203 genes that exhibited an altered CORT response in the presence of T₃, suggesting that T₃ plays a significant role in modulating CORT-regulated genes. We also found 80 genes synergistically induced, and 73 genes synergistically repressed by T₃ + CORT treatment. We performed in silico analysis using publicly available mouse neuronal chromatin immunoprecipitation-sequencing datasets and identified a considerable number of synergistically regulated genes with TH receptor and GC receptor peaks mapping within 1 kb of chromatin marks indicative of hormone-responsive enhancer regions. Functional annotation clustering of synergistically regulated genes reveal the relevance of proteasomal-dependent degradation, neuroprotective effect of growth hormones, and neuroinflammatory responses as key pathways to how TH and GC may coordinately influence learning and memory. Taken together, our transcriptome data represents a promising exploratory dataset for further study of common molecular mechanisms behind synergistic TH and GC gene regulation, and identify specific genes and their role in processes mediated by cross-talk between the thyroid and stress axes in a mammalian hippocampal model system.

Development of disorder-specific normative data for growth in children with cerebral palsy

The purpose of this study was to create growth-percentiles for Caucasian children with cerebral palsy (CP). The studied parameters were height and age. In a retrospective analysis, we converted measurements collected in our center to create disorder-specific percentiles of normative data. Patients were stratified due to sex (male and female) and to mobility levels using the gross motor function classification system (GMFCS) (A = walking; GMFCS I-III, B = non walking; GMFCS IV-V) into four groups. In total, 2363 measurements in patients 0-18 years were collected. The mean age for group "Am" was 6.8 years (n = 862), group "Bm" 7.6 years (n = 563), group "Af" 7.7 years (n = 600), and group "Bf" 8.2 years (n = 366). The created percentiles for all groups were below the reference percentiles for healthy Caucasian children (KiGGS). The median curve for children with GMFCS levels I-III is slightly above the 3rd percentile, whereas the 50th percentile for GMFCS levels IV-V is mostly below the 3rd KiGGS centile.Conclusion: In conclusion, children with cerebral palsy are smaller than healthy children. The difference between 50th percentile of CP patients compared to healthy children supports the need for the use of disorder-specific growth charts. Those charts can help clinicians differentiate growth disorders in patients with CP. What is Known: • Children with cerebral palsy are shorter than healthy children and height is influenced by level of ambulation. • Currently, only reference percentiles of American children with mixed ethical backgrounds are available to evaluate growth. What is New: • This paper presents disorder-specific reference percentiles for longitudinal growth of Caucasian children with cerebral palsy depending on motor function. • These percentiles allow to asses longitudinal growth in children with cerebral palsy to detect other additional diseases impairing growth.

Endocrine parameters in association with bone mineral accrual in young female vocational ballet dancers

Less is known on bone mass gains in dancers involved in vocational dance training. The present study found that, as young vocational dancers progress on their professional training, their bone health remains consistently lower compared to non-exercising controls. Endocrine mechanisms do not seem to explain these findings.

PURPOSE

Little is known on bone mass development in dancers involved in vocational training. The aim of the present study was to model bone mineral content (BMC) accruals and to determine whether circulating levels of oestrogens, growth hormone (GH), and insulin-like growth factor I (IGF-1) explain differences in bone mass gains between vocational dance students and matched controls.

METHODS

The total of 67 vocational female dancers (VFDs) and 68 aged-matched controls (12.1 ± 1.9 years and 12.7 ± 2.0 years at baseline, respectively) were followed for two consecutive years (34 VFD and 31 controls remained in the study for the full duration). BMC was evaluated annually at impact [femoral neck (FN); lumbar spine (LS)] and non-impact sites (forearm) using DXA. Anthropometry, age at menarche (questionnaire), and hormone serum concentrations (immunoradiometric assays) were also assessed for the same period.

RESULTS

VFD demonstrated consistently reduced body weight (p < 0.001) and BMC at all three anatomical sites (p < 0.001) compared to controls throughout the study period. Menarche, body weight, GH, and IGF-1 were significantly associated with bone mass changes over time (p < 0.05) but did not explain group differences in BMC gains at impact sites (p > 0.05). However, body weight did explain the differences between groups in terms of BMC gains at the forearm (non-impact site).

CONCLUSION

Two consecutive years of vocational dance training revealed that young female dancers demonstrate consistently lower bone mass compared to controls at both impact and non-impact sites. The studied endocrine parameters do not seem to explain group differences in terms of bone mass gains at impact sites.

Vitamin D and growth hormone in children: a review of the current scientific knowledge

Background

Human growth is a complex mechanism that depends on genetic, environmental, nutritional and hormonal factors. The main hormone involved in growth at each stage of development is growth hormone (GH) and its mediator, insulin-like growth factor 1 (IGF-1). In contrast, vitamin D is involved in the processes of bone growth and mineralization through the regulation of calcium and phosphorus metabolism. Nevertheless, no scientific study has yet elucidated how they interact with one another, especially as a dysfunction in which one influences the other, even if numerous biochemical and clinical studies confirm the presence of a close relationship.

Main body

We reviewed and analyzed the clinical studies that have considered the relationship between vitamin D and the GH/IGF-1 axis in pediatric populations. We found two main areas of interest: the vitamin D deficiency status in patients affected by GH deficit (GHD) and the relationship between serum vitamin D metabolites and IGF-1. Although limited by some bias, from the analysis of the studies presented in the scientific literature, it is possible to hypothesize a greater frequency of hypovitaminosis D in the subjects affected by GHD, a reduced possibility of its correction with only substitution treatment with recombinant growth hormone (rGH) and an improvement of IGF-1 levels after supplementation treatment with vitamin D.

Conclusions

These results could be followed by preventive interventions aimed at reducing the vitamin D deficit in pediatric age. In addition, further research is needed to fully understand how vitamin D and growth are intertwined.

Undernutrition and growth in the developing world

PURPOSE OF REVIEW

Despite targeted interventions, an estimated 150.8 million children under 5 years globally are still stunted, of which more than half live in Asia and more than one-third live in Africa. This review summarizes our current knowledge regarding how longitudinal bone growth is regulated by nutritional intake in the developing world. Dietary macronutrients and micronutrients necessary for growth are also briefly reviewed.

RECENT FINDINGS

Recent advances include investigations of nutritionally sensitive regulators of growth as well as prospective evaluations of the role of specific dietary components on growth in order to better assess their impact.

SUMMARY

Further investigation is required to understand how nutrition impacts growth, the mechanisms underlying stunting and to optimize therapeutic strategies for children who are at risk for growth attenuation or are stunted in low and middle-income countries (LMICs).

Light-dark rhythms during incubation of broiler chicken embryos and their effects on embryonic and post hatch leg bone development

There are indications that lighting schedules applied during incubation can affect leg health at hatching and during rearing. The current experiment studied effects of lighting schedule: continuous light (24L), 12 hours of light, followed by 12 hours of darkness (12L:12D), or continuous darkness (24D) throughout incubation of broiler chicken eggs on the development and strength of leg bones, and the role of selected hormones in bone development. In the tibiatarsus and femur, growth and ossification during incubation and size and microstructure at day (D)0, D21, and D35 post hatching were measured. Plasma melatonin, growth hormone, and IGF-I were determined perinatally. Incidence of tibial dyschondroplasia, a leg pathology resulting from poor ossification at the bone’s epiphyseal plates, was determined at slaughter on D35. 24L resulted in lower embryonic ossification at embryonic day (E)13 and E14, and lower femur length, and lower tibiatarsus weight, length, cortical area, second moment of area around the minor axis, and mean cortical thickness at hatching on D0 compared to 12L:12D especially. Results were long term, with lower femur weight and tibiatarsus length, cortical and medullary area of the tibiatarsus, and second moment of area around the minor axis, and a higher incidence of tibial dyschondroplasia for 24L. Growth hormone at D0 was higher for 24D than for 12L:12D, with 24L intermediate, but plasma melatonin and IGF-I did not differ between treatments, and the role of plasma melatonin, IGF-I, and growth hormone in this process was therefore not clear. To conclude, in the current experiment, 24L during incubation of chicken eggs had a detrimental effect on embryonic leg bone development and later life leg bone strength compared to 24D and 12L:12D, while the light-dark rhythm of 12L:12D may have a stimulating effect on leg health.

Physiology of puberty in boys and girls and pathological disorders affecting its onset

Puberty is a physiological event involving the attainment of reproductive capability and complete development of sexual and physical organs. Changing from childhood to adulthood is a complex process and is tightly controlled by interconnection pathways at the level of the hypothalamus which can be influenced by environmental, psychosocial, and endocrine factors. Although various mechanisms underlying the onset of normal puberty have been investigated in humans and animals, the exact molecular mechanisms thereof remain unclear. The aim of this review is to summarize the current state of knowledge and provide a synoptic overview about the physiology of puberty in adolescent boys and girls, and describe pathological disorders affecting its onset.

Glucocorticoid-activation system mediated glucocorticoid-insulin-like growth factor 1 (GC-IGF1) axis programming alteration of adrenal dysfunction induced by prenatal caffeine exposure

Glucocorticoids play a major factor in fetal maturation and fate decision after birth. We have previously demonstrated that prenatal caffeine exposure (PCE) resulted in adrenal dysplasia. However, its molecular mechanism has not been clarified. In the present study, a rat model of intrauterine growth retardation (IUGR) was established by PCE, and offspring were sacrificed. Moreover, NCI-H295 A cells were used to confirm glucocorticoid-related molecular mechanism. Results showed that PCE fetal weight decreased, and the IUGR rate increased, while serum corticosterone levels increased but insulin-like growth factor 1 (IGF1) levels decreased. Fetal adrenals exhibited an activated glucocorticoid-activation system, and the downregulated expression of IGF1 signal pathway and steroidal synthetases. For adult rats, there was no significant change in the glucocorticoid-activation system in the PCE group, the IGF1 signal pathway showed increased trend, and the expression levels of adrenal steroidal synthetases were close to normal. The data in vitro showed that the cortisol of 1200 nM can inhibit the expression of adrenocortical cell steroidal synthetases and IGF1 signal pathway when compared with the control. Meanwhile, the glucocorticoid-activation system was activated while GR inhibitor mifepristone can reverse the effect of cortisol. Furthermore, cortisol can also promote GR into the nucleus after its activation. Based on these findings, we speculated that high concentrations of glucocorticoid in utero led to GR in the nucleus through its activation and then inhibited the IGF1 signaling pathway by activating the glucocorticoid-activation system, which could further downregulate steroid synthesis.

Maternal Iodine Insufficiency and Excess Are Associated with Adverse Effects on Fetal Growth: A Prospective Cohort Study in Wuhan, China

Background

Maternal iodine status has been suggested to affect birth outcomes. Few studies have focused on its effects on fetal growth during pregnancy.

Objective

This study aimed to assess maternal iodine status during early pregnancy and further examine the relation between maternal iodine status and fetal growth.

Methods

A total of 2087 singleton-pregnant women participating in the Tongji Maternal and Child Health Cohort study were involved. Urinary iodine concentration (UIC) and creatinine concentration were measured in spot urine samples collected in early pregnancy (<20 wk of gestation). Fetal head circumference (HC), femur length (FL), and estimated fetal weight (EFW) were evaluated by ultrasonography in each trimester. A multiple linear regression model was used to examine the association of iodine status with fetal growth characteristics, and a mixed-effects model was used to assess longitudinal effect.

Results

The median UIC and iodine-to-creatinine (I/Cr) ratio were 178 μg/L and 234 μg/g, respectively. The prevalence of insufficient iodine status (I/Cr ratio <150 μg/g) was 19.8%(n = 414), of adequate iodine status (150-249 μg/g) was 34.8% (n = 726), of iodine status above the requirements (250-499 μg/g) was 32.1% (n = 669), and of excessive iodine status (≥500 μg/g) was 13.3% (n = 278). Maternal iodine insufficiency was inversely associated with fetal FL in the second and third trimesters. In stratified analysis, significant interactions were found between maternal iodine status and age as well as parity (all P < 0.05). The longitudinal analyses showed negative associations of maternal insufficient, more than adequate, or excessive iodine status with fetal growth during pregnancy (all P < 0.05).

Conclusions

In central China, maternal iodine insufficiency and excess coexisted during early pregnancy and they both adversely affected fetal growth. There is an urgent need for ongoing monitoring of iodine status among vulnerable pregnant women in order to optimize iodine nutrition during pregnancy.

Applications for non-invasive thyroid hormone measurements in mammalian ecology, growth, and maintenance

Thyroid hormones (THs) play a pivotal role in the regulation of metabolic activity throughout all life stages. Cross-talk with other hormone systems permits THs to coordinate metabolic changes as well as modifications in growth and maintenance in response to changing environmental conditions. The scope of this review is to explain the relevant basics of TH endocrinology, highlight pertinent topics that have been investigated so far, and offer guidance on measuring THs in non-invasively collected matrices. The first part of the review provides an overview of TH biochemistry, which is necessary to understand and interpret the findings of existing studies and to apply non-invasive TH monitoring. The second part focuses on the role of THs in mammalian ecology, and the third part highlights the role of THs in growth and maintenance. The fourth part deals with the advantages and difficulties of measuring THs in non-invasively collected samples. This review concludes with a summary that considers future directions in the study of THs.

Transcriptome analyses reveal molecular mechanisms that regulate endochondral ossification in amphibian Bufo gargarizans during metamorphosis

BACKGROUND

A developmental transition from aquatic to terrestrial existence is one of the most important events in the evolution of terrestrial vertebrates. Amphibian metamorphosis is a classic model to study this transition. The development of the vertebrate skeleton can reflect its evolutionary history. Endochondral ossification serves a vital role in skeletal development. Thus, we sought to unravel molecular mechanisms that regulate endochondral ossification during Bufo gargarizans metamorphosis.

METHODS

The alizarin red-alcian blue double staining method was used to visualize the skeletal development of B. gargarizans during metamorphosis. RNA sequencing (RNA-seq) was used to explore the transcriptome of B. gargarizans in four key developmental stages during metamorphosis. Real-time quantitative PCR (RT-qPCR) was used to validate the expression patterns of endochondral ossification related genes.

RESULTS

Endochondral ossification increased gradually in skeletal system of B. gargarizans during metamorphosis. A total of 137,264 unigenes were assembled and 44,035 unigenes were annotated. 10,352 differentially expressed genes (DEGs) were further extracted among four key developmental stages. In addition, 28 endochondral ossification related genes were found by searching for DEG libraries in B. gargarizans. Of the 28 genes, 10 genes were validated using RT-qPCR.

CONCLUSIONS

The exquisite coordination of the 28 genes is essential for regulation of endochondral ossification during B. gargarizans metamorphosis.

GENERAL SIGNIFICANCE

The present study will not only provide an invaluable genomic resource and background for further research of endochondral ossification in amphibians but will also aid in enhancing our understanding of the evolution of terrestrial vertebrates.

Differences in the auxological characters of children with short stature - Differential diagnostic possibilities of hypothyreosis

This study aimed to define the differences in growth characteristics in the three most frequent causes of growth retardation - growth hormone deficiency, hypothyreosis and constitutional delay of growth and development - in order to provide diagnostic means for distinguishing these disorders. The study included 166 children with growth disorders aged 4-18 years. The height for age, the bone age using the TW3 method, the predicted height as the target height and the current prediction using the TW3 method were studied. For bone age, the radius, ulna and short bones compartment (RUS) and carpal bones (CARP) were evaluated separately and the difference in their delay in relation to chronological age (ΔBA_RUS_CARP) was determined. The relationship of the studied variables with sex and the underlying diagnosis was tested and the relationship of hypothyreosis and growth data was estimated. The model was tested on the growth data of 104 randomly selected patients with a growth disorder. The largest significant distinction was demonstrated by the difference ΔBA_RUS_CARP in hypothyreosis. The created linear regression model was highly statistically significant (χ² = 19.4, p < 0.0001) and showed high selectivity (0.609, 95% CI 0.409; 0.808) as well as high specificity (0.864, 95% CI 0.781; 0.946). The clinical validity of the model demonstrated a 61% predictive value for the detection and an 81% successful specification of hypothyreosis. The study demonstrated the possibility of distinguishing suspected hypothyreosis from other causes of growth retardation based on differences in severity of the ossification delay in skeletal compartments of the hand.

Effects of Iodized Salt and Iodine Supplements on Prenatal and Postnatal Growth: A Systematic Review

Hypothyroidism due to iodine deficiency can impair physical development, most visibly in the marked stunting of myxedematous cretinism caused by severe in utero iodine deficiency. Whether iodine repletion improves growth in noncretinous children is uncertain. Therefore, the aim of our systematic review was to assess the effects of iodine fortification or supplementation on prenatal and postnatal growth outcomes in noncretinous children. Following Cochrane methods and PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) reporting guidelines, we searched 10 databases including 2 Chinese databases (latest search February 2017). We included randomized and nonrandomized controlled trials (RCTs; non-RCTs), controlled before-after (CBA) studies, and interrupted time-series studies in pregnant women and children (≤18 y), which compared the effects of iodine (any form, dose, regimen) to placebo, noniodized salt, or no intervention on prenatal and postnatal growth outcomes. We calculated mean differences with 95% CIs, performed random-effects meta-analyses, and assessed the quality of evidence with the use of GRADE (Grading of Recommendations Assessment, Development and Evaluation). We included 18 studies (13 RCTs, 4 non-RCTs, 1 CBA) (n = 5729). Iodine supplementation of severely iodine-deficient pregnant women increased mean birthweight [mean difference (MD): 200 g; 95% CI: 183, 217 g; n = 635; 2 non-RCTs] compared to controls, but the quality of this evidence was assessed as very low. Iodine repletion across the other groups showed no effects on primary growth outcomes (quality of evidence mostly low and very low). Meta-analyses showed a positive effect in moderate-to-mildly iodine-deficient schoolchildren on insulin-like growth factor-1 (MD: 38.48 ng/mL; 95% CI: 6.19, 70.76 ng/mL; n = 498; 2 RCTs, low-quality evidence) and insulin-like growth factor binding protein-3 (MD: 0.46 μg/mL; 95% CI: 0.25, 0.66 μg/mL; n = 498; 2 RCTs, low-quality evidence). In conclusion, we identified few well-designed trials examining the effects of iodine repletion on growth. We are uncertain whether prenatal iodine repletion increases infant growth. Postnatal iodine repletion may improve growth factors but has no clear effects on somatic growth. Our systematic review was registered with PROSPERO as CRD42014012940.

Possible effects of an early diagnosis and treatment in patients with growth hormone deficiency: the state of art

Growth hormone deficiency (GHD) is a relatively uncommon and heterogeneous endocrine disorder presenting in childhood with short stature. However, during the neonatal period, the metabolic effects of GHD may to require prompt replacement therapy to avoid possible life-threatening complications. An increasing amount of data suggests the importance of an early diagnosis and treatment of GHD because of its auxological, metabolic, and neurodevelopmental features with respect to the patients diagnosed and treated later in life.

The available results show favourable auxological outcomes for patients with GHD diagnosed and treated with r-hGH early in life compared with those from patients with GHD who do not receive this early diagnosis and treatment. Because delayed referral for GHD diagnosis and treatment is still frequent, these results highlight the need for more attention in the diagnosis and treatment of GHD.

Despite these very encouraging data regarding metabolic and neurodevelopmental features, further studies are needed to better characterize these findings. Overall, the importance of early diagnosis and treatment of GHD needs to be addressed.

Thyroxine Exposure Effects on the Cranial Base

Thyroid hormone is important for skull bone growth, which primarily occurs at the cranial sutures and synchondroses. Thyroid hormones regulate metabolism and act in all stages of cartilage and bone development and maintenance by interacting with growth hormone and regulating insulin-like growth factor. Aberrant thyroid hormone levels and exposure during development are exogenous factors that may exacerbate susceptibility to craniofacial abnormalities potentially through changes in growth at the synchondroses of the cranial base. To elucidate the direct effect of in utero therapeutic thyroxine exposure on the synchondroses in developing mice, we provided scaled doses of the thyroid replacement drug, levothyroxine, in drinking water to pregnant C57BL6 wild-type dams. The skulls of resulting pups were subjected to micro-computed tomography analysis revealing less bone volume relative to tissue volume in the synchondroses of mouse pups exposed in utero to levothyroxine. Histological assessment of the cranial base area indicated more active synchondroses as measured by metabolic factors including Igf1. The cranial base of the pups exposed to high levels of levothyroxine also contained more collagen fiber matrix and an increase in markers of bone formation. Such changes due to exposure to exogenous thyroid hormone may drive overall morphological changes. Thus, excess thyroid hormone exposure to the fetus during pregnancy may lead to altered craniofacial growth and increased risk of anomalies in offspring.