Sally Radovick

Obesity is a growing public health problem worldwide, and GH and IGF-1 have been studied as potential therapeutic targets for managing this condition. This review article aims to provide a comprehensive view of the interplay between GH and IGF-1 and metabolism within the context of obesity. We conducted a systematic review of the literature that was published from 1993 to 2023, using MEDLINE, Embase, and Cochrane databases. We included studies that investigated the effects of GH and IGF-1 on adipose tissue metabolism, energy balance, and weight regulation in humans and animals. Our review highlights the physiological functions of GH and IGF-1 in adipose tissue metabolism, including lipolysis and adipogenesis. We also discuss the potential mechanisms underlying the effects of these hormones on energy balance, such as their influence on insulin sensitivity and appetite regulation. Additionally, we summarize the current evidence regarding the efficacy and safety of GH and IGF-1 as therapeutic targets for managing obesity, including in pharmacological interventions and hormone replacement therapy. Finally, we address the challenges and limitations of targeting GH and IGF-1 in obesity management.

Short stature is a common reason for a child to visit the endocrinologist, and can be a variant of normal or secondary to an underlying pathologic cause. Pathologic causes include growth hormone deficiency (GHD), which can be congenital or acquired later. GHD can be isolated or can occur with other pituitary hormone deficiencies. The diagnosis of GHD requires thorough clinical, biochemical, and radiographic investigations. Genetic testing may also be helpful in some patients. Treatment with recombinant human growth hormone (rhGH) should be initiated as soon as the diagnosis is made and patients should be monitored closely to evaluate response to treatment and for potential adverse effects.

Nonalcoholic fatty liver disease (NAFLD), the most common liver disease, has become a silent worldwide pandemic. The incidence of NAFLD correlates with the rise in obesity, type 2 diabetes, and metabolic syndrome. A hallmark featureof NAFLD is excessive hepatic fat accumulation or steatosis, due to dysregulated hepatic fat metabolism, which can progress to nonalcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. Currently, there are no approved pharmacotherapies to treat this disease. Here, we have found that activation of the kisspeptin 1 receptor (KISS1R) signaling pathway has therapeutic effects in NAFLD. Using high-fat diet–fed mice, we demonstrated that a deletion of hepatic Kiss1r exacerbated hepatic steatosis. In contrast, enhanced stimulation of KISS1R protected against steatosis in wild-type C57BL/6J mice and decreased fibrosis using a diet-induced mouse model of NASH. Mechanistically, we found that hepatic KISS1R signaling activates the master energy regulator, AMPK, to thereby decrease lipogenesis and progression to NASH. In patients with NAFLD and in high-fat diet–fed mice, hepatic KISS1/KISS1R expression and plasma kisspeptin levels were elevated, suggesting a compensatory mechanism to reduce triglyceride synthesis. These findings establish KISS1R as a therapeutic target to treat NASH.

In mammals, the neuroendocrine system, which includes the communication between the hypothalamus and the pituitary, plays a major role in controlling body growth and cellular metabolism. GH produced from the pituitary somatotroph is considered the master regulator of somatic development and involved, directly and indirectly, in carbohydrate and lipid metabolism via complex, yet well-defined, signaling pathways. GH production from the pituitary gland is primarily regulated by the counter-regulatory effects of the hypothalamic GHRH and SST hormones. The role of IGF-1 feedback regulation in GH production has been demonstrated by pharmacologic interventions and in genetically modified mouse models. In the present review, we discuss the role of IGF-1 in the regulation of the GH-axis as it controls somatic growth and metabolic homeostasis. We present genetically modified mouse models that maintain the integrity of the GH/GHRH-axis with the single exception of IGF-1 receptor (IGF-1R) deficiency in the hypothalamic GHRH neurons and somatotroph that reveals a novel mechanism controlling adipose tissues physiology and energy expenditure.

During female mammal reproductive tract development, epithelial cells of the lower Müllerian duct are committed to become stratified squamous epithelium of vagina and ectocervix, when the expression of ΔNp63 transcription factor is induced by mesenchymal cells. The absence of ΔNp63 expression leads to adenosis, the putative precursor of vaginal adenocarcinoma. Our previous studies with genetically engineered mouse models have established that fibroblast growth factor (FGF)/mitogen-activated protein kinase (MAPK), bone morphogenetic protein (BMP)/SMAD, and activin A/runt related transcription factor 1 (RUNX1) signaling pathways are independently required for ΔNp63 expression in Müllerian duct epithelium (MDE). Here we report that sine oculis homeobox homolog 1 (SIX1) plays a critical role in the activation of ΔNp63 locus in MDE as a downstream transcription factor of mesenchymal signals. In mouse developing reproductive tract, SIX1 expression was restricted to MDE of the future cervix and vagina. SIX1 expression was totally absent in SMAD4 null MDE and was reduced in RUNX1 null and FGFR2 null MDE, indicating that SIX1 is under the control of vaginal mesenchymal factors, BMP4, activin A and FGF7/10. Furthermore, Six1, Runx1 and Smad4 gene-dose-dependently activated ΔNp63 expression in MDE within vaginal fornix. Using a mouse model of diethylstilbestrol (DES)-associated vaginal adenosis, we found DES action through epithelial estrogen receptor α (ESR1) down-regulates SIX1 and RUNX1 in MDE within the vaginal fornix. This study establishes that the vaginal/ectocervical cell fate of MDE is regulated by a collaboration of multiple transcription factors including SMAD4, SIX1 and RUNX1, and the down-regulation of these key transcription factors leads to vaginal adenosis. Author Summary: In embryogenesis, differentiation fate of cells is specified through constant communication between neighboring cells. In this study, we investigated the molecular mechanism of epithelial cell fate commitment in the lower female reproductive organs utilizing mouse genetic models. The cell fate of epithelial cells in the uterus, cervix and vagina is directed by signaling from mesenchymal cells. We demonstrated that within the epithelial cells of the developing vagina, signals from mesenchymal cells are integrated into activities of transcription factors including SMAD4, RUNX1 and SIX1, which dose-dependently co-operate in the determination of vaginal epithelial cell fate. Disruption of these processes alters the cell fate from vaginal to uterine epithelium, resulting in a condition called vaginal adenosis, a putative precursor of vaginal adenocarcinoma. Women exposed to diethylstilbestrol (DES) in the womb have about 40 times the risk of developing vaginal adenocarcinoma. We determined that developmental exposure to DES induces vaginal adenosis by repressing SIX1 and RUNX1 through ESR1 in the epithelial cells. This discovery enhances the understanding of how early-life events, such as exposure to endocrine disruptors, causes vaginal adenosis, and thus may contribute to the prevention and therapeutic treatment of idiopathic vaginal adenocarcinoma.

Growth hormone (GH) deficiency affects up to one in 4000 children and is usually treated with daily injections of GH whilst the child is still growing. With children typically diagnosed at around five years old, this can mean over 10 years of therapy, which can place a considerable burden on the child and the parent. Over three-quarters of children are estimated to be not fully compliant with therapy, which can compromise their chances of attaining their target height. In recent years, interactive mobile health (smart phone or tablet) interventions using game-like concepts, so called ‘gamification’, have increased in popularity and have demonstrated success in promoting positive self-management behaviour in children with chronic conditions, such as diabetes. The application of gamified interventions has the potential to support adherence to therapy and positive behaviour in children with GH deficiency in a number of ways: (1) By providing education in a format that the child understands and accepts (e.g., using behavioural constructs to facilitate explaining why adherence is important); (2) By providing a mechanism to reduce the anxiety and stress associated with administering the injection (e.g., diversion with a virtual pet); and (3) By providing feedback to encourage ongoing engagement (e.g., rewards, progression through levels).