Atypical defects resulting in growth hormone insensitivity

JAK-STAT signaling as an ARDS therapeutic target: Status and future trends

Acute respiratory distress syndrome (ARDS) is characterized by noncardiogenic pulmonary edema. It has a high mortality rate and lacks effective pharmacotherapy. With the outbreak of COVID-19 worldwide, the mortality of ARDS has increased correspondingly, which makes it urgent to find effective targets and strategies for the treatment of ARDS. Recent clinical trials of Janus kinase (JAK) inhibitors in treating COVID-19-induced ARDS have shown a positive outcome, which makes the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway a potential therapeutic target for treating ARDS. Here, we review the complex cause of ARDS, the molecular JAK/STAT pathway involved in ARDS pathology, and the progress that has been made in strategies targeting JAK/STAT to treat ARDS. Specifically, JAK/STAT signaling directly participates in the progression of ARDS or colludes with other pathways to aggravate ARDS. We summarize JAK and STAT inhibitors with ARDS treatment benefits, including inhibitors in clinical trials and preclinical studies and natural products, and discuss the side effects of the current JAK inhibitors to reveal future trends in the design of JAK inhibitors, which will help to develop effective treatment strategies for ARDS in the future.

Biochemical discrepancies in the evaluation of the somatotroph axis: Elevated GH or IGF-1 levels do not always diagnose acromegaly

The most frequent diagnosis underlying the finding of an elevated growth hormone (GH) and insulin-like growth factor-1 (IGF-1) is acromegaly due to a GH-secreting pituitary tumour. However, GH and IGF-1 levels can be discordant in patients with acromegaly due to early or partially treated disease, or there might be another cause of high GH or high IGF-1 unrelated to acromegaly, such as pre-analytical and technical pitfalls, physiological circumstances and pathological conditions. High GH and normal or low serum IGF-1, or alternatively, normal GH with elevated serum IGF-1, should be carefully assessed to avoid misinterpreting the activity of acromegaly or misdiagnosing a patient with acromegaly. We summarise here these biochemical discrepancies in the evaluation of the somatotroph axis.

Clinical Profiles and Genetic Spectra of 814 Chinese Children With Short Stature

CONTEXT

Data and studies based on exome sequencing for the genetic evaluation of short stature are limited, and more large-scale studies are warranted. Some factors increase the likelihood of a monogenic cause of short stature, including skeletal dysplasia, severe short stature, and small for gestational age (SGA) without catch-up growth. However, whether these factors can serve as predictors of molecular diagnosis remains unknown.

OBJECTIVE

We aimed to explore the diagnostic efficiency of the associated risk factors and their exome sequences for screening.

METHODS

We defined and applied factors that increased the likelihood of monogenic causes of short stature in diagnostic genetic tests based on next-generation sequencing (NGS) in 814 patients with short stature and at least 1 other factor.

RESULTS

Pathogenic/likely pathogenic (P/LP) variants in genes, copy number variations, and chromosomal abnormalities were identified in 361 patients. We found P/LP variants among 111 genes, and RASopathies comprised the most important etiology. Short stature combined with other phenotypes significantly increased the likelihood of a monogenic cause, including skeletal dysplasia, facial dysmorphism, and intellectual disability, compared with simple severe short stature (<-3 SD scores). We report novel candidate pathogenic genes, KMT2C for unequivocal growth hormone insensitivity and GATA6 for SGA.

CONCLUSION

Our study identified the diagnostic characteristics of NGS in short stature with different risk factors. Our study provides novel insights into the current understanding of the etiology of short stature in patients with different phenotypes.

Transcriptome-Wide Analysis of Human Liver Reveals Age-Related Differences in the Expression of Select Functional Gene Clusters and Evidence for a PPP1R10-Governed 'Aging Cascade'

A transcriptome-wide analysis of human liver for demonstrating differences between young and old humans has not yet been performed. However, identifying major age-related alterations in hepatic gene expression may pinpoint ontogenetic shifts with important hepatic and systemic consequences, provide novel pharmacogenetic information, offer clues to efficiently counteract symptoms of old age, and improve the overarching understanding of individual decline. Next-generation sequencing (NGS) data analyzed by the Mann-Whitney nonparametric test and Ensemble Feature Selection (EFS) bioinformatics identified 44 transcripts among 60,617 total and 19,986 protein-encoding transcripts that significantly (p = 0.0003 to 0.0464) and strikingly (EFS score > 0.3:16 transcripts; EFS score > 0.2:28 transcripts) differ between young and old livers. Most of these age-related transcripts were assigned to the categories 'regulome', 'inflammaging', 'regeneration', and 'pharmacogenes'. NGS results were confirmed by quantitative real-time polymerase chain reaction. Our results have important implications for the areas of ontogeny/aging and the age-dependent increase in major liver diseases. Finally, we present a broadly substantiated and testable hypothesis on a genetically governed 'aging cascade', wherein PPP1R10 acts as a putative ontogenetic master regulator, prominently flanked by IGFALS and DUSP1. This transcriptome-wide analysis of human liver offers potential clues towards developing safer and improved therapeutic interventions against major liver diseases and increased insights into key mechanisms underlying aging.

Genetic Characterization of Short Stature Patients With Overlapping Features of Growth Hormone Insensitivity Syndromes

CONTEXT

Growth hormone insensitivity (GHI) in children is characterized by short stature, functional insulin-like growth factor (IGF)-I deficiency, and normal or elevated serum growth hormone (GH) concentrations. The clinical and genetic etiology of GHI is expanding.

OBJECTIVE

We undertook genetic characterization of short stature patients referred with suspected GHI and features which overlapped with known GH-IGF-I axis defects.

METHODS

Between 2008 and 2020, our center received 149 GHI referrals for genetic testing. Genetic analysis utilized a combination of candidate gene sequencing, whole exome sequencing, array comparative genomic hybridization, and a targeted whole genome short stature gene panel.

RESULTS

Genetic diagnoses were identified in 80/149 subjects (54%) with 45/80 (56%) having known GH-IGF-I axis defects (GHR n = 40, IGFALS n = 4, IGFIR n = 1). The remaining 35/80 (44%) had diagnoses of 3M syndrome (n = 10) (OBSL1 n = 7, CUL7 n = 2, and CCDC8 n = 1), Noonan syndrome (n = 4) (PTPN11 n = 2, SOS1 n = 1, and SOS2 n = 1), Silver-Russell syndrome (n = 2) (loss of methylation on chromosome 11p15 and uniparental disomy for chromosome 7), Class 3-5 copy number variations (n = 10), and disorders not previously associated with GHI (n = 9) (Barth syndrome, autoimmune lymphoproliferative syndrome, microcephalic osteodysplastic primordial dwarfism type II, achondroplasia, glycogen storage disease type IXb, lysinuric protein intolerance, multiminicore disease, macrocephaly, alopecia, cutis laxa, and scoliosis syndrome, and Bloom syndrome).

CONCLUSION

We report the wide range of diagnoses in 149 patients referred with suspected GHI, which emphasizes the need to recognize GHI as a spectrum of clinical entities in undiagnosed short stature patients. Detailed clinical and genetic assessment may identify a diagnosis and inform clinical management.

Digital Health for Supporting Precision Medicine in Pediatric Endocrine Disorders: Opportunities for Improved Patient Care

Digitalization of healthcare delivery is rapidly fostering development of precision medicine. Multiple digital technologies, known as telehealth or eHealth tools, are guiding individualized diagnosis and treatment for patients, and can contribute significantly to the objectives of precision medicine. From a basis of "one-size-fits-all" healthcare, precision medicine provides a paradigm shift to deliver a more nuanced and personalized approach. Genomic medicine utilizing new technologies can provide precision analysis of causative mutations, with personalized understanding of mechanisms and effective therapy. Education is fundamental to the telehealth process, with artificial intelligence (AI) enhancing learning for healthcare professionals and empowering patients to contribute to their care. The Gulf Cooperation Council (GCC) region is rapidly implementing telehealth strategies at all levels and a workshop was convened to discuss aspirations of precision medicine in the context of pediatric endocrinology, including diabetes and growth disorders, with this paper based on those discussions. GCC regional investment in AI, bioinformatics and genomic medicine, is rapidly providing healthcare benefits. However, embracing precision medicine is presenting some major new design, installation and skills challenges. Genomic medicine is enabling precision and personalization of diagnosis and therapy of endocrine conditions. Digital education and communication tools in the field of endocrinology include chatbots, interactive robots and augmented reality. Obesity and diabetes are a major challenge in the GCC region and eHealth tools are increasingly being used for management of care. With regard to growth failure, digital technologies for growth hormone (GH) administration are being shown to enhance adherence and response outcomes. While technical innovations become more affordable with increasing adoption, we should be aware of sustainability, design and implementation costs, training of HCPs and prediction of overall healthcare benefits, which are essential for precision medicine to develop and for its objectives to be achieved.

Hepatocardiac or Cardiohepatic Interaction: From Traditional Chinese Medicine to Western Medicine

There is a close relationship between the liver and heart based on "zang-xiang theory," "five-element theory," and "five-zang/five-viscus/five-organ correlation theory" in the theoretical system of Traditional Chinese Medicine (TCM). Moreover, with the development of molecular biology, genetics, immunology, and others, the Modern Medicine indicates the existence of the essential interorgan communication between the liver and heart (the heart and liver). Anatomically and physiologically, the liver and heart are connected with each other primarily via "blood circulation." Pathologically, liver diseases can affect the heart; for example, patients with end-stage liver disease (liver failure/cirrhosis) may develop into "cirrhotic cardiomyopathy," and nonalcoholic fatty liver disease (NAFLD) may promote the development of cardiovascular diseases via multiple molecular mechanisms. In contrast, heart diseases can affect the liver, heart failure may lead to cardiogenic hypoxic hepatitis and cardiac cirrhosis, and atrial fibrillation (AF) markedly alters the hepatic gene expression profile and induces AF-related hypercoagulation. The heart can also influence liver metabolism via certain nonsecretory cardiac gene-mediated multiple signals. Moreover, organokines are essential mediators of organ crosstalk, e.g., cardiomyokines link the heart to the liver, while hepatokines link the liver to the heart. Therefore, both TCM and Western Medicine, and both the basic research studies and the clinical practices, all indicate that there exist essential "heart-liver axes" and "liver-heart axes." To investigate the organ interactions between the liver and heart (the heart and liver) will help us broaden and deepen our understanding of the pathogenesis of both liver and heart diseases, thus improving the strategies of prevention and treatment in the future.

Mouse models of growth hormone insensitivity

Growth hormone (GH) induces pleiotropic effects on growth and metabolism via binding and subsequent activation of the growth hormone receptor (GHR) and its downstream signaling pathways. Growth hormone insensitivity (GHI) describes a group of disorders in which there is resistance to the action of GH and resultant insulin-like growth factor I (IGF-I) deficiency. GHI is commonly due to genetic disorders of the GH receptor causing GH receptor deficiency (e.g. Laron Syndrome (LS)), decreased activation of GHR, or defects in post-receptor signaling molecules. Genetically altered mouse lines have been invaluable to better understand the physiological impact of GHI due to the ability to do invasive and longitudinal measures of metabolism, growth, and health on a whole animal or in individual tissues/cells. In the current review, the phenotype of mouse lines with GHI will be reviewed. Mouse lines to be discussed include: 1) GHR-/- mice with a gene disruption in the GHR that results in no functional GHR throughout life, also referred to as the Laron mouse, 2) mice with temporal loss of GHR (aGHRKO) starting at 6 weeks of age, 3) mice transgenic for a GHR antagonist (GHA mice), 4) mice with GHI in select tissues or cells generated via Cre-lox or related technology, and 5) assorted mice with defects in post-receptor signaling molecules. Collectively, these mouse lines have revealed an intriguing role of GH action in health, disease, and aging.

Activation of the MAPK pathway (RASopathies) and partial growth hormone insensitivity

RASopathies are a heterogeneous group of syndromes caused by germline mutations in genes encoding components of the RAS/MAPK pathway. Postnatal short stature is a cardinal feature of the RASopathies. Although the pathophysiology of these conditions is not fully understood to date, growth hormone insensitivity is one possibility, based on the observation of low IGF-1 values, generally preserved GH secretion and suboptimal growth response to recombinant human GH therapy. In this review, we will discuss the clinical and experimental evidence of GH insensitivity in patients with Noonan syndrome and other RASopathies, as well as their molecular basis.

Regulatory role of NF-κB in growth plate chondrogenesis and its functional interaction with Growth Hormone

Nuclear Factor kappa B (NF-kB) is a family of transcription factors that participates in the regulation of cell proliferation, migration, and apoptosis. Impaired NF-kB activity appears to be involved in the pathophysiology of inflammatory states, autoimmune diseases, and cancer. Genetic manipulation in mice leading to impaired NF-kB function is associated with abnormal limb development and delayed bone growth. We have previously shown in rodent cultured chondrocytes and cultured metatarsal bones that NF-kB promotes longitudinal bone growth and growth plate chondrocyte function. These NF-kB growth-promoting effects appear to be facilitated by Growth Hormone (GH) and Insulin-like Growth factor-1 (IGF-1). These stimulatory effects of GH and IGF-1 on NF-kB activity are supported by observational evidence in humans; a number of individuals carrying mutations that alter NF-kB function exhibit growth failure and GH insensitivity.

Significance of Direct Confirmation of Growth Hormone Insensitivity for the Diagnosis of Primary IGF-I Deficiency

Primary insulin-like growth factor-I (IGF-I) deficiency is a synonym of growth hormone (GH) insensitivity (GHI), however the necessity of direct confirmation of GH resistance by IGF-I generation test (IGF-GT) is discussed. GHI may disturb intrauterine growth, nevertheless short children born small for gestational age (SGA) are treated with GH. We tested the hypothesis that children with appropriate birth size (AGA), height standard deviation score (SDS) <−3.0, GH peak in stimulation tests (stimGH) ≥10.0 µg/L, IGF-I <2.5 centile, and excluded GHI may benefit during GH therapy. The analysis comprised 21 AGA children compared with 6 SGA and 20 GH-deficient ones, with height SDS and IGF-I as in the studied group. All patients were treated with GH up to final height (FH). Height velocity, IGF-I, and IGF binding protein-3 (IGFBP-3) concentrations before and during first year of treatment were assessed. Effectiveness of therapy was better in GHD than in IGF-I deficiency (IGFD), with no significant difference between SGA and AGA groups. All but two AGA children responded well to GH. Pretreatment IGF-I and increase of height velocity (HV) during therapy but not the result of IGF-GT correlated with FH. As most AGA children with apparent severe IGFD benefit during GH therapy, direct confirmation of GHI seems necessary to diagnose true primary IGFD in them.

Etiology of short stature in Indian children and an assessment of the growth hormone-insulin-like growth factor axis in children with idiopathic short stature

Background Our objectives were to evaluate the etiology of short stature, assess the prevalence of idiopathic short stature (ISS) and assess the growth hormone (GH)-insulin-like growth factor (IGF) axis in children with ISS. Methods A stepwise diagnostic evaluation was done in 394 children aged 4-16 years with short stature. Children with no definitive etiology were labeled as ISS. In these children, baseline IGF-1, IGF binding protein-3 (IGFBP-3) and stimulated IGF-1 after administration of GH for 4 days were measured. Results Hypothyroidism (in 18.1%) and ISS (in 15.5%) were the commonest causes of short stature. In children with ISS (n=61), the mean baseline and stimulated IGF-1 standard deviation scores (SDSs) were -1.2±1.0 and -0.3±1.4, respectively, with levels below -2 SDS in 13 (21%) and six (10%) children, respectively. In 33 (54%) of the ISS patients, response to GH was suboptimal (increment in the IGF-1 level <40%). There was no difference in the mean peak GH, IGFBP-3 and baseline and stimulated IGF-1 levels between children with familial and non-familial ISS. A significant positive correlation of height SDS with baseline IGF-1 SDS (r=0.28, p=0.026), stimulated IGF-1 SDS (r=0.32, p=0.010) and ΔIGF-1 SDS (r=0.26, p=0.036) was observed in children with ISS. Conclusions Hypothyroidism and ISS were the commonest etiologies for short stature. The baseline IGF-1 was below -2 SDS in 21% and the increment after GH stimulation was suboptimal in 54% of children, indicating that a substantial proportion of children with ISS had an impaired GH-IGF axis.

Expressions of IGF-1, ERK, GLUT4, IRS-1 in metabolic syndrome complicated with colorectal cancer and their associations with the clinical characteristics of CRC

BACKGROUND

Epidemiological data have revealed that colorectal cancer (CRC) risk is increased in patients with Metabolic syndrome.

OBJECTIVE

To explore the expressions of IGF-1, ERK, GLUT4, IRS-1 in MS patients with CRC and their associations with the clinical characteristics of CRC.

METHODS

We investigated the expressions of IGF-1, ERK, GLUT4 and IRS-1 in greater omental adipose tissues of 168 MS patients with/without CRC, 85 CRC patients without MS and 98 healthy controls by RT-PCR, and analyzed the relationships between their expressions and clinical characteristics of CRC.

RESULTS

The expression levels of IGF-1 and ERK in MS patients with/without CRC were higher while the expression levels of GLUT4 were lower compared with CRC patients without MS and healthy controls (P< 0.01). The expression levels of IGF-1 and ERK in MS patients with CRC were higher while expression levels of GLUT4 were lower compared to MS patients without CRC (P< 0.01). Expression levels of ERK, IGF-1, GLUT4 were associated with clinical characteristics of CRC, including tumor size, distant metastasis and advanced stages (III/IV) (P< 0.05).

CONCLUSIONS

Expressions of IGF-1, ERK and GLUT4 in greater omental adipose tissues might be useful biomarkers and predictive targets in the diagnosis of CRC.

A genetic approach to evaluation of short stature of undetermined cause

Short stature is a common presentation to paediatric endocrinologists. After exclusion of major endocrine or systemic disease, most children with short stature are diagnosed based on a description of their growth pattern and the height of their parents (eg, familial short stature). Height is a polygenic trait and genome-wide association studies have identified many of the associated genetic loci. Here we review the application of genetic studies, including copy number variant analysis, targeted gene panels, and whole-exome sequencing in children with idiopathic short stature. We estimate 25-40% of children diagnosed with idiopathic short stature could receive a molecular diagnosis using these technologies. A molecular diagnosis for short stature is important for affected individuals and their families and might inform treatment decisions surrounding use of growth hormone or insulin-like growth factor 1 therapy.

Primary growth hormone insensitivity and psychomotor delay

We report a case of short stature irresponsive to growth hormone (GH) replacement therapy. Low GH response to provocative tests and undetectable IGF-1 levels had suggested GH deficiency, while response to therapy indicated GH insensitivity. Molecular evaluation of the GH/IGF-1 axis should be performed in these cases to improve diagnosis and therapy.

Growth hormone insensitivity: Mexican case report

Herein, we present a 14-year-old patient with short stature (134 cm) referred from Paediatrics to our department for complementary evaluation since growth hormone (GH) treatment failed to show any improvement. He was born premature and small for gestational age. Genital examination classified the patient as Tanner I-II with small penis and testicular size for his age. Biochemical analyses revealed normal GH levels with low serum insulin-like growth factor-1 (IGF-1). Molecular diagnosis confirmed several mutations in IGF1R and IGFALS, and so he was diagnosed with Laron Syndrome or GH insensibility and treated with IGF-1 substitutive therapy.

Learning points

Evaluation of the GH/IGF-1 axis when short stature does not respond to conservative treatment must be included in the ordinary practice.Laron Syndrome real incidence should be calculated once undiagnosed cases arise, as treatment, due to lack of market, is unaffordable.Even when adulthood is reached, and no longitudinal growth can be achieved, still IGF-1 treatment in Laron Syndrome patients should be pursued as metabolic and protective derangements could arise.

Genetic variations at the human growth hormone receptor (GHR) gene locus are associated with idiopathic short stature

GH plays an essential role in the growing child by binding to the growth hormone receptor (GHR) on target cells and regulating multiple growth promoting and metabolic effects. Mutations in the GHR gene coding regions result in GH insensitivity (dwarfism) due to a dysfunctional receptor protein. However, children with idiopathic short stature (ISS) show growth impairment without GH or GHR defects. We hypothesized that decreased expression of the GHR gene may be involved. To test this, we investigated whether common genetic variants (microsatellites, SNPs) in regulatory regions of the GHR gene region were associated with the ISS phenotype. Genotyping of a GT‐repeat microsatellite in the GHR 5′UTR in a Montreal ISS cohort (n = 37 ISS, n = 105 controls) revealed that the incidence of the long/short (L/S) genotype was 3.3× higher in ISS children than controls (P = 0.04, OR = 3.85). In an Italian replication cohort (n = 143 ISS, n = 282 controls), the medium/short (M/S) genotype was 1.9× more frequent in the male ISS than controls (P = 0.017, OR = 2.26). In both ISS cohorts, logistic regression analysis of 27 SNPs showed an association of ISS with rs4292454, while haplotype analysis revealed specific risk haplotypes in the 3′ haploblocks. In contrast, there were no differences in GT genotype frequencies in a cohort of short stature (SS) adults versus controls (CARTaGENE: n = 168 SS, n = 207 controls) and the risk haplotype in the SS cohort was located in the most 5′ haploblock. These data suggest that the variants identified are potentially genetic markers specifically associated with the ISS phenotype.

MECHANISMS IN ENDOCRINOLOGY: Novel genetic causes of short stature

The fast technological development, particularly single nucleotide polymorphism array, array-comparative genomic hybridization, and whole exome sequencing, has led to the discovery of many novel genetic causes of growth failure. In this review we discuss a selection of these, according to a diagnostic classification centred on the epiphyseal growth plate. We successively discuss disorders in hormone signalling, paracrine factors, matrix molecules, intracellular pathways, and fundamental cellular processes, followed by chromosomal aberrations including copy number variants (CNVs) and imprinting disorders associated with short stature. Many novel causes of GH deficiency (GHD) as part of combined pituitary hormone deficiency have been uncovered. The most frequent genetic causes of isolated GHD are GH1 and GHRHR defects, but several novel causes have recently been found, such as GHSR, RNPC3, and IFT172 mutations. Besides well-defined causes of GH insensitivity (GHR, STAT5B, IGFALS, IGF1 defects), disorders of NFκB signalling, STAT3 and IGF2 have recently been discovered. Heterozygous IGF1R defects are a relatively frequent cause of prenatal and postnatal growth retardation. TRHA mutations cause a syndromic form of short stature with elevated T3/T4 ratio. Disorders of signalling of various paracrine factors (FGFs, BMPs, WNTs, PTHrP/IHH, and CNP/NPR2) or genetic defects affecting cartilage extracellular matrix usually cause disproportionate short stature. Heterozygous NPR2 or SHOX defects may be found in ∼3% of short children, and also rasopathies (e.g., Noonan syndrome) can be found in children without clear syndromic appearance. Numerous other syndromes associated with short stature are caused by genetic defects in fundamental cellular processes, chromosomal abnormalities, CNVs, and imprinting disorders.