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International Journal of Molecular... Dec 2021Ever since the discoveries that human hair follicles (HFs) display the functional peripheral equivalent of the hypothalamic-pituitary-adrenal axis, exhibit elements of... (Review)
Review
Ever since the discoveries that human hair follicles (HFs) display the functional peripheral equivalent of the hypothalamic-pituitary-adrenal axis, exhibit elements of the hypothalamic-pituitary-thyroid axis, and even generate melatonin and prolactin, human hair research has proven to be a treasure chest for the exploration of neurohormone functions. However, growth hormone (GH), one of the dominant neurohormones of human neuroendocrine physiology, remains to be fully explored in this context. This is interesting since it has long been appreciated clinically that excessive GH serum levels induce distinct human skin pathology. Acromegaly, or GH excess, is associated with hypertrichosis, excessive androgen-independent growth of body hair, and hirsutism in females, while dysfunctional GH receptor-mediated signaling (Laron syndrome) is associated with alopecia and prominent HF defects. The outer root sheath keratinocytes have recently been shown to express functional GH receptors. Furthermore, and contrary to its name, recombinant human GH is known to inhibit female human scalp HFs' growth ex vivo, likely via stimulating the expression of the catagen-inducing growth factor, TGF-β2. These limited available data encourage one to systematically explore the largely uncharted role of GH in human HF biology to uncover nonclassical functions of this core neurohormone in human skin physiology.
Topics: Female; Hair Follicle; Human Growth Hormone; Humans; Receptors, Somatotropin; Skin
PubMed: 34948002
DOI: 10.3390/ijms222413205 -
Reviews in Endocrine & Metabolic... Mar 2021Laron Syndrome (LS) [OMIm#262500], or primary GH insensitivity, was first described in 1966 in consanguineous Jewish families from Yemen. LS is characterized by a... (Review)
Review
Laron Syndrome (LS) [OMIm#262500], or primary GH insensitivity, was first described in 1966 in consanguineous Jewish families from Yemen. LS is characterized by a typical phenotype that includes dwarfism, obesity and hypogenitalism. The disease is caused by deletions or mutations of the GH-receptor gene, causing high serum GH and low IGF-I serum levels. We studied 75 patients from childhood to adult age. After early hypoglycemia due to the progressive obesity, patients tend to develop glucose intolerance and diabetes. The treatment is by recombinant IGF-I, which improves the height and restores some of the metabolic parameters. An unexpected finding was that patients homozygous for GH-R defects are protected from malignancy lifelong, not so heterozygotes or double heterozygote subjects. We estimate that there are at least 500 patients worldwide, unfortunately only few treated.
Topics: Adult; Child; Growth Hormone; Humans; Insulin-Like Growth Factor I; Laron Syndrome; Mutation; Neoplasms; Obesity; Receptors, Somatotropin
PubMed: 32964395
DOI: 10.1007/s11154-020-09595-0 -
Frontiers in Physiology 2022Growth hormone (GH) is a peptide hormone that can signal directly through its receptor or indirectly through insulin-like growth factor 1 (IGF-1) stimulation. GH draws... (Review)
Review
Growth hormone (GH) is a peptide hormone that can signal directly through its receptor or indirectly through insulin-like growth factor 1 (IGF-1) stimulation. GH draws its name from its anabolic effects on muscle and bone but also has distinct metabolic effects in multiple tissues. In addition to its metabolic and musculoskeletal effects, GH is closely associated with aging, with levels declining as individuals age but GH action negatively correlating with lifespan. GH's effects have been studied in human conditions of GH alteration, such as acromegaly and Laron syndrome, and GH therapies have been suggested to combat aging-related musculoskeletal diseases, in part, because of the decline in GH levels with advanced age. While clinical data are inconclusive, animal models have been indispensable in understanding the underlying molecular mechanisms of GH action. This review will provide a brief overview of the musculoskeletal effects of GH, focusing on clinical and animal models.
PubMed: 35665221
DOI: 10.3389/fphys.2022.867921 -
Frontiers in Endocrinology 2023The growth hormone (GH)-insulin-like growth factor-1 (IGF1) signaling pathway emerged in recent years as a key determinant of aging and longevity. Disruption of this... (Review)
Review
The growth hormone (GH)-insulin-like growth factor-1 (IGF1) signaling pathway emerged in recent years as a key determinant of aging and longevity. Disruption of this network in different animal species, including flies, nematodes and mouse, was consistently associated with an extended lifespan. Epidemiological analyses have shown that patients with Laron syndrome (LS), the best-characterized disease under the umbrella of the congenital IGF1 deficiencies, seem to be protected from cancer. While aging and cancer, as a rule, are considered diametrically opposite processes, modern lines of evidence reinforce the notion that aging and cancer might, as a matter of fact, be regarded as divergent manifestations of identical biochemical and cellular underlying processes. While the effect of individual mutations on lifespan and health span is very difficult to assess, genome-wide screenings identified a number of differentially represented aging- and longevity-associated genes in patients with LS. The present review summarizes recent data that emerged from comprehensive analyses of LS patients and portrays a number of previously unrecognized targets for GH-IGF1 action. Our article sheds light on complex aging and longevity processes, with a particular emphasis on the role of the GH-IGF1 network in these mechanisms.
Topics: Humans; Mice; Animals; Laron Syndrome; Aging; Longevity; Growth Hormone; Human Growth Hormone; Neoplasms
PubMed: 37941907
DOI: 10.3389/fendo.2023.1291812 -
Journal of Postgraduate Medicine 2020[This corrects the article DOI: 10.4103/0022-3859.138816].
[This corrects the article DOI: 10.4103/0022-3859.138816].
PubMed: 32270785
DOI: 10.4103/0022-3859.169761 -
Reviews in Endocrine & Metabolic... Mar 2021Growth hormone (GH) induces pleiotropic effects on growth and metabolism via binding and subsequent activation of the growth hormone receptor (GHR) and its downstream... (Review)
Review
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.
Topics: Animals; Growth Disorders; Growth Hormone; Human Growth Hormone; Humans; Insulin-Like Growth Factor I; Laron Syndrome; Mice; Receptors, Somatotropin
PubMed: 33037595
DOI: 10.1007/s11154-020-09600-6 -
Hormone Research in Paediatrics 2022The growth hormone (GH)-insulin-like growth factor (IGF) cascade is central to the regulation of growth and metabolism. This article focuses on the history of the... (Review)
Review
The growth hormone (GH)-insulin-like growth factor (IGF) cascade is central to the regulation of growth and metabolism. This article focuses on the history of the components of the IGF system, with an emphasis on the peptide hormones, IGF-I and -II, their cell surface receptors, and the IGF binding proteins (IGFBPs) and IGFBP proteases that regulate the availability of the peptide hormones for interaction with their receptors in relevant target tissues. We describe landmark events in the evolution of the somatomedin hypothesis, including evidence that has become available from experiments at the molecular and cellular levels, whole animal and tissue-specific gene knockouts, studies of cancer epidemiology, identification of prismatic human cases, and short- and long-term clinical trials of IGF-I therapy in humans. In addition, this new evidence has expanded our clinical definition of GH insensitivity (GHI) beyond growth hormone receptor mutations (classic Laron syndrome) to include conditions that cause primary IGF deficiency by impacting post-receptor signal transduction, IGF production, IGF availability to interact with the IGF-I receptor (IGF-1R), and defects in the IGF-1R, itself. We also discuss the clinical aspects of IGFs, from their description as insulin-like activity, to the use of IGF-I in the diagnosis and treatment of GH deficiency, and to the use of recombinant human IGF-I for therapy of children with GHI.
Topics: Animals; Humans; Insulin-Like Growth Factor I; Laron Syndrome; Peptide Hormones; Protein Processing, Post-Translational; Signal Transduction; Somatomedins; Insulin-Like Growth Factor II
PubMed: 36446332
DOI: 10.1159/000527123 -
Xenotransplantation Mar 2021Xenotransplantation research has made considerable progress in recent years, largely through the increasing availability of pigs with multiple genetic modifications,... (Review)
Review
Xenotransplantation research has made considerable progress in recent years, largely through the increasing availability of pigs with multiple genetic modifications, effective immunosuppressive therapy, and anti-inflammatory therapy to protect pig tissues from the primate immune and inflammatory responses and correct molecular incompatibilities. Further study is required regarding identification and investigation of physiological incompatibilities. Although the exact cause remains uncertain, we and others have observed relatively rapid growth of kidney xenografts after transplantation into nonhuman primates (NHPs). There has also been some evidence of growth, or at least ventricular hypertrophy, of the pig heart after orthotopic transplantation into NHPs. Rapid growth could be problematic, particularly with regard to the heart within the relatively restricted confines of the chest. It has been suggested that the problem of rapid growth of the pig organ after transplantation could be resolved by growth hormone receptor (GHR) gene knockout in the pig. The GHR, although most well-known for regulating growth, has many other biological functions, including regulating metabolism and controlling physiological processes. Genetically modified GHRKO pigs have recently become available. We provide data on their growth compared to comparable pigs that do not include GHRKO, and we have reviewed the literature regarding the effect of GHRKO, and its relevance to xenotransplantation.
Topics: Animals; Animals, Genetically Modified; Graft Rejection; Heterografts; Receptors, Somatotropin; Swine; Transplantation, Heterologous; Transplants
PubMed: 33058285
DOI: 10.1111/xen.12652 -
Hormone Research in Paediatrics 2022The aim of the study was to describe focal epilepsy in patients with Laron syndrome (LS).
OBJECTIVE
The aim of the study was to describe focal epilepsy in patients with Laron syndrome (LS).
METHODS
Data were retrieved from medical records of a single-center cohort of 75 patients with LS.
RESULTS
We describe for the first time 4 patients with concomitant focal epilepsy and LS. Two of them experienced episodes of status epilepticus. Electroencephalogram examination in all 4 patients showed interictal epileptiform discharges in the temporal regions. Three achieved long-term seizure freedom on antiseizure medications.
CONCLUSION
Patients with LS may be at risk of developing focal epilepsy, which seems to be unrelated to hypoglycemic episodes in childhood.
Topics: Electroencephalography; Epilepsies, Partial; Humans; Laron Syndrome; Retrospective Studies; Seizures
PubMed: 35358968
DOI: 10.1159/000524350