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Wydra A, Czajka-Oraniec I, Wydra J, Zgliczyński W. The influence of growth hormone deficiency on bone health and metabolisms. Reumatologia 2023; 61:239-247. [PMID: 37745147 PMCID: PMC10515129 DOI: 10.5114/reum/170244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Accepted: 08/01/2023] [Indexed: 09/26/2023] Open
Abstract
Growth hormone (GH) is a key peptide hormone in the regulation of bone metabolism, through its systemic and paracrine action mediated directly as well as by insulin-like growth factor-1 (IGF-1). Growth hormone exerts pleiotropic effects leading to an increase in linear bone growth, accumulation of bone mineral content and preservation of peak bone mass. Furthermore, it influences protein, lipid, and carbohydrate metabolism.Growth hormone deficiency (GHD) causes a low bone turnover rate leading to reduced bone mineral density (BMD) and increased bone fragility. The results of GH insufficiency are the most pronounced among children as it negatively affects longitudinal bone growth, causing short stature and in adolescents, in whom it hinders the acquisition of peak bone mass. Most studies show that treatment with recombinant human growth hormone (rhGH) in GHD patients could improve BMD and decrease fracture risk. This review aims to summarize the pathophysiology, clinical picture and management of bone complications observed in GHD.
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Affiliation(s)
- Arnika Wydra
- Department of Endocrinology, Centre of Postgraduate Medical Education, Bielanski Hospital, Warsaw, Poland
| | - Izabella Czajka-Oraniec
- Department of Endocrinology, Centre of Postgraduate Medical Education, Bielanski Hospital, Warsaw, Poland
| | - Jakub Wydra
- Department of Internal Medicine, Bielanski Hospital, Warsaw, Poland
| | - Wojciech Zgliczyński
- Department of Endocrinology, Centre of Postgraduate Medical Education, Bielanski Hospital, Warsaw, Poland
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Morgan SA, Berryman DE, List EO, Lavery GG, Stewart PM, Kopchick JJ. Regulation of 11β-HSD1 by GH/IGF-1 in key metabolic tissues may contribute to metabolic disease in GH deficient patients. Growth Horm IGF Res 2022; 62:101440. [PMID: 34814007 DOI: 10.1016/j.ghir.2021.101440] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 11/01/2021] [Accepted: 11/14/2021] [Indexed: 11/19/2022]
Abstract
Patients with growth hormone deficiency (GHD) have many clinical features in common with Cushing's syndrome (glucocorticoid excess) - notably visceral obesity, insulin resistance, muscle myopathy and increased vascular mortality. Within key metabolic tissues, 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) converts cortisone to the active glucocorticoid, cortisol (11-dehydrocorticosterone and corticosterone in rodents respectively), and thus amplifies local glucocorticoid action. We hypothesize that 11β-HSD1 expression is negatively regulated by growth hormone (GH), and that GHD patients have elevated 11β-HSD1 within key metabolic tissues (leading to increased intracellular cortisol generation) which contributes to the clinical features of this disease. To identify the impact of GH excess/resistance on 11β-HSD1 in vivo, we measured mRNA expression in key metabolic tissues of giant mice expressing the bovine GH (bGH) gene, dwarf mice with a disrupted GH receptor (GHRKO) gene and mice expressing a gene encoding a GH receptor antagonist (GHA). Additionally, we assessed urine steroid markers of 11β-HSD1 activity in both GHRKO and bGH animals. 11β-HSD1 expression was decreased in gastrocnemius muscle (0.43-fold, p < 0.05), subcutaneous adipose (0.53-fold, p < 0.05) and epididymal adipose tissue (0.40-fold, p < 0.05), but not liver, in bGH mice compared to WT controls. This was paralleled by an increased percentage of 11-DHC (inactive glucocorticoid) present in the urine of bGH mice compared to WT controls (2.5-fold, p < 0.01) - consistent with decreased systemic 11β-HSD1 activity. By contrast, expression of 11β-HSD1 was increased in the liver of GHRKO (2.7-fold, p < 0.05) and GHA mice (2.0-fold, p < 0.05) compared to WT controls, but not gastrocnemius muscle, subcutaneous adipose tissue or epididymal adipose tissue. In summary, we have demonstrated a negative relationship between GH action and 11β-HSD1 expression which appears to be tissue specific. These data provide evidence that increased intracellular cortisol production within key tissues may contribute to metabolic disease in GHD patients.
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Affiliation(s)
- Stuart A Morgan
- Institute of Metabolism & Systems Research, College of Medical and Dental Sciences, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK.
| | - Darlene E Berryman
- Edison Biotechnology Institute, Ohio University/The Ridges, 1 Water Tower Drive, Building #25, Athens, OH 45701, USA
| | - Edward O List
- Edison Biotechnology Institute, Ohio University/The Ridges, 1 Water Tower Drive, Building #25, Athens, OH 45701, USA
| | - Gareth G Lavery
- Institute of Metabolism & Systems Research, College of Medical and Dental Sciences, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK
| | - Paul M Stewart
- Institute of Metabolism & Systems Research, College of Medical and Dental Sciences, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK; Faculty of Medicine and Health, University of Leeds, Leeds, UK
| | - John J Kopchick
- Edison Biotechnology Institute, Ohio University/The Ridges, 1 Water Tower Drive, Building #25, Athens, OH 45701, USA
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Stich FM, Huwiler S, D'Hulst G, Lustenberger C. The Potential Role of Sleep in Promoting a Healthy Body Composition: Underlying Mechanisms Determining Muscle, Fat, and Bone Mass and Their Association with Sleep. Neuroendocrinology 2022; 112:673-701. [PMID: 34348331 DOI: 10.1159/000518691] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 07/22/2021] [Indexed: 11/19/2022]
Abstract
Sleep plays an essential role in human life. While sleep is a state elicited by the brain, its vital role reaches beyond maintaining brain health. Unhealthy sleeping habits have been associated with increased risk for inflammation, obesity, or diabetes. Evidence is emerging that sleep guides processes playing an important role in promoting the regulation of endocrine function involved in tissue regeneration and tissue remodelling. Thereby, sleep presumably is a critical factor contributing to the balance of core body tissues: bone, fat, and muscle mass. Given the increasing prevalence of various chronic diseases and comorbidities due to unhealthy lifestyle choices, sleep could be a key target to promote a healthy body composition up until old age. Here, we review the potential role of sleep and its underlying brain oscillations in body core tissues turnover. Specifically, we discuss potential underlying mechanisms linking sleep to body composition, both during rest and under challenging conditions. Among other described pathways, we highlight the possible role of the growth hormone that was found to be involved in the homeostasis of all core body tissues and has been strongly linked to brain activity dominating deep sleep, the so-called slow waves. Finally, we formulate important questions to be addressed in future research on the effect of sleep on body composition and specifically emphasize the importance of intervention studies to move from correlative to causal evidence.
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Affiliation(s)
- Fabia M Stich
- Neural Control of Movement Lab, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Stephanie Huwiler
- Neural Control of Movement Lab, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Gommaar D'Hulst
- Laboratory of Exercise and Health, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Caroline Lustenberger
- Neural Control of Movement Lab, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland
- Sleep & Health Zurich, University Center of Competence, University of Zurich, Zurich, Switzerland
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Ricci Bitti S, Franco M, Albertelli M, Gatto F, Vera L, Ferone D, Boschetti M. GH Replacement in the Elderly: Is It Worth It? Front Endocrinol (Lausanne) 2021; 12:680579. [PMID: 34211437 PMCID: PMC8239420 DOI: 10.3389/fendo.2021.680579] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 06/02/2021] [Indexed: 11/24/2022] Open
Abstract
Growth hormone (GH), once the age of linear growth is completed, continues to play a fundamental role for the human body. In adulthood, GH contributes to regulate muscle, cardiovascular and bone metabolism. The same happens in old age, although there is less data on the effect of GH in the elderly. Regardless the age of onset, a reduced quality of life (QoL), an increased cardiovascular risk and an accelerated age-related decline in physical strength have been demonstrated in the elderly with GH deficiency (EGHD). In adults with GH deficiency (AGHD), recent studies suggest a role of GH replacement therapy (GHrt) in improving lean/fat mass ratio, blood pressure, lipid profile, bone metabolism and QoL. Despite these recent studies, there is still a lack of randomized controlled trials proving these positive effects in EGHD. Moreover, the lack of a long-term positive outcome on mortality, and the cost of GHrt could often impact on treatment decision-making and lead to postpone or avoid the prescription. The aim of this mini-review is to summarize the available data on GHrt in EGHD, in order to highlight its weaknesses and strengths and to provide directions to clinicians that will help in the management of this specific set of patients.
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Affiliation(s)
- Silvia Ricci Bitti
- Endocrinology Unit, Department of Internal Medicine and Medical Specialties, School of Medical and Pharmaceutical Sciences, University of Genova, Genova, Italy
| | - Marta Franco
- Endocrinology Unit, Department of Internal Medicine and Medical Specialties, School of Medical and Pharmaceutical Sciences, University of Genova, Genova, Italy
| | - Manuela Albertelli
- Endocrinology Unit, Department of Internal Medicine and Medical Specialties, School of Medical and Pharmaceutical Sciences, University of Genova, Genova, Italy
- Endocrinology Unit, IRCCS Policlinico San Martino, Genova, Italy
| | - Federico Gatto
- Endocrinology Unit, IRCCS Policlinico San Martino, Genova, Italy
| | - Lara Vera
- Endocrinology Unit, IRCCS Policlinico San Martino, Genova, Italy
| | - Diego Ferone
- Endocrinology Unit, Department of Internal Medicine and Medical Specialties, School of Medical and Pharmaceutical Sciences, University of Genova, Genova, Italy
- Endocrinology Unit, IRCCS Policlinico San Martino, Genova, Italy
| | - Mara Boschetti
- Endocrinology Unit, Department of Internal Medicine and Medical Specialties, School of Medical and Pharmaceutical Sciences, University of Genova, Genova, Italy
- Endocrinology Unit, IRCCS Policlinico San Martino, Genova, Italy
- *Correspondence: Mara Boschetti,
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Yuen KCJ, Llahana S, Miller BS. Adult growth hormone deficiency: clinical advances and approaches to improve adherence. Expert Rev Endocrinol Metab 2019; 14:419-436. [PMID: 31721610 DOI: 10.1080/17446651.2019.1689119] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 11/01/2019] [Indexed: 12/17/2022]
Abstract
Introduction: There have been significant clinical advances in the understanding of the diagnosis and benefits of long-term recombinant human growth hormone (rhGH) replacement in adults with GH deficiency (GHD) since its approval in 1996 by the United States Food and Drug Administration.Areas covered: We searched PubMed, Medline, CINAHL, EMBASE and PsychInfo databases between January 2000 and June 2019 for published studies evaluating adults with GHD. We reviewed the data of the oral macimorelin test compared to the GHRH plus arginine and the insulin tolerance tests that led to its approval by the United States FDA and European Medicines Agency for adult diagnostic testing. We summarize the clinical advances of long-term benefits of rhGH therapy and the potential effects of GH receptor polymorphisms on individual treatment responsiveness. We identify that non-adherence and discontinuation rates are high and recommend strategies to support patients to improve adherence. We also provide an overview of several long-acting GH (LAGH) preparations currently under development and their potential role in improving treatment adherence.Expert opinion: This article summarizes recent clinical advances in rhGH replacement therapy, the biological and molecular aspects that may influence rhGH action, and offers practical strategies to enhance adherence in adults with GHD.
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Affiliation(s)
- Kevin C J Yuen
- Barrow Pituitary Center, Barrow Neurological Institute, University of Arizona College of Medicine and Creighton School of Medicine, Phoenix, AZ, USA
| | - Sofia Llahana
- Division of Nursing, School of Health Sciences, City University of London, London, UK
| | - Bradley S Miller
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
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Loftus J, Camacho-Hubner C, Hey-Hadavi J, Goodrich K. Targeted literature review of the humanistic and economic burden of adult growth hormone deficiency. Curr Med Res Opin 2019; 35:963-973. [PMID: 30411985 DOI: 10.1080/03007995.2018.1546682] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Quality of life (QoL) and health economic data are becoming increasingly important factors in healthcare decision making. While there is a wealth of information establishing the benefit of growth hormone (GH) replacement therapy in adults with growth hormone deficiency (aGHD), recent reviews on the QoL and health economic impact of aGHD and the effect of treatment on these factors is limited. OBJECTIVE The aim of this article is to summarize the impact of early and sustained treatment on the QoL and economic burden of aGHD by conducting a targeted literature review. METHODS Standard electronic databases, including PubMed and the Cochrane collaboration website, were searched for publications between January 2006 and July 2016 for evidence of the humanistic and economic burden of aGHD. Search terms included growth hormone deficiency, health-related quality of life, HRQoL, patient-reported outcomes, outcome assessment, well-being and adherence. RESULTS The literature search identified 732 initial hits and a final 14 publications were included. The analysis showed that the economic burden of aGHD is largely driven by the productivity losses associated with the disease. This is because most patients with aGHD are of working age and the QoL domains (memory & concentration and energy & vitality) most commonly affected by aGHD severely impair a person's ability to work and may limit their contribution to society. CONCLUSION Untreated aGHD can seriously affect patients' functioning. Early and continued treatment with GH replacement therapy could potentially improve the QoL and reduce the economic burden associated with aGHD. This review has limitations: only English language articles published since January 2006 were included and many of the studies were conducted in the Nordic countries; it is unclear how representative these studies are of the population as a whole. This was a literature review and not a systematic review, as it was thought to be unlikely that, in this rare disease, any additional publications would have been identified. Overall, this review reveals a paucity of data in this underserved population and points to research gaps which could be addressed with new studies.
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Giagulli VA, Castellana M, Perrone R, Guastamacchia E, Iacoviello M, Triggiani V. GH Supplementation Effects on Cardiovascular Risk in GH Deficient Adult Patients: A Systematic Review and Meta-analysis. Endocr Metab Immune Disord Drug Targets 2018; 17:285-296. [PMID: 28925898 PMCID: PMC5925873 DOI: 10.2174/1871530317666170919121729] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 08/30/2017] [Accepted: 09/07/2017] [Indexed: 01/02/2023]
Abstract
BACKGROUND AND OBJECTIVE The current meta-analysis aims at evaluating whether the existing clinical evidence may ascertain the effects of growth hormone (GH) replacement therapy on cardiovascular risk, both in isolated GH deficiency (GHD) and in compensated panhypopituitarism including GH deficit. METHODS Original articles published from 1991 to 2015 were searched on Medline (Pubmed). Among an overall number of 181 potentially suitable studies, 24 fulfilled the selection criteria and were included in the analysis. Data aggregation was carried out through the calculation of the absolute risk reduction. The meta-analysis was then conducted by means of a fixed-effects model, according to the heterogeneity test (Chi-square statistic). RESULTS Fat-free mass (FFM) increase and fat mass (FM) reduction were found, together with a C-LDL reduction, a wide variation in glycaemia and a neutral effect on glycated haemoglobin (HbA1c) and blood pressure. These effects were valid both for isolated GHD patients and for those with compensated panhypopituitarism. The global outcome D showed a nonsignificant reduction of the overall cardiovascular risk (0.53; 95% C.I. -1.23, 2.85). CONCLUSION Our meta-analysis shows no signnificatly positive trend in cardiovascular risk after both short and long-term GH supplementation therapy in adult GHD patients. However, a reduction of LDL cholesterol levels has been found. No differences were found between isolated GHD participants and those affected by panhypopituitarism well compensated since at least 3 months.
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Affiliation(s)
- Vito A Giagulli
- Outpatient Clinic for Endocrinology and Metabolic Diseases, Conversano Hospital, ASL Bari Via De Amicis, 70014 Conversano, Italy.,Interdisciplinary Department of Medicine-Section of Internal Medicine, Geriatrics, Endocrinology and Rare Diseases, University of Bari "A. Moro", Bari, Italy
| | - Marco Castellana
- Section of Internal Medicine, Endocrinology, Andrology and Metabolic Diseases, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Piazza Giulio Cesare 11, 70124, Bari, Italy
| | | | - Edoardo Guastamacchia
- Interdisciplinary Department of Medicine-Section of Internal Medicine, Geriatrics, Endocrinology and Rare Diseases, University of Bari "A. Moro", Bari, Italy
| | - Massimo Iacoviello
- Cardiology Unit, Cardiothoracic Department, University of Bari, School of Medicine, Policlinico, Piazza Giulio Cesare 11, 70124 Bari, Italy
| | - Vincenzo Triggiani
- Interdisciplinary Department of Medicine-Section of Internal Medicine, Geriatrics, Endocrinology and Rare Diseases, University of Bari "A. Moro", Bari, Italy
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Abstract
CONTEXT Recombinant human growth hormone (rHGH) has become a target of abuse in the sporting world. Conversely, sports medicine clinicians may encounter athletes using rHGH to achieve normalcy in the context of growth hormone (GH) deficiency. EVIDENCE ACQUISITION Medline and PubMed databases were queried using the following keywords: GH, GH physiology, GH deficiency, acromegaly, GH athlete, GH sports, GH athletic performance, and GH deficiency concussion. Articles focusing on GH physiology, deficiency, excess, and its effects in both deficient and healthy patients were included. STUDY DESIGN Clinical review. LEVEL OF EVIDENCE Level 3. RESULTS GH is a naturally occurring hormone with important roles in human physiology. Patients with GH deficiency (GHD) present variably, and GHD has numerous etiologies. rHGH treatment has substantial therapeutic benefits for patients with GHD. The benefits of rHGH treatment in otherwise-healthy adults are uncertain. GH excess may cause health problems such as acromegaly. Professional, collegiate, and international sports leagues and associations have banned rHGH use to maintain athlete health, safety, and fair play. Athletes misusing GH may face prolonged suspensions from competition. Implementing GH abuse testing is challenging, but new methods, such as the biomarker testing procedure, are being finalized. CONCLUSION rHGH is not only an important therapeutic agent for GH-deficient patients but also a target of abuse in competitive athletics. Its benefits in a healthy, adult population are uncertain. A safe exercise and competition plan, developed with a physician knowledgeable of GH use, physiology, and abuse potential, should be of benefit to a longitudinal clinician-patient relationship.
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Affiliation(s)
- David M Siebert
- Department of Family Medicine, Sports Medicine Section, University of Washington, Seattle, Washington
| | - Ashwin L Rao
- Department of Family Medicine, Sports Medicine Section, University of Washington, Seattle, Washington
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Treatment with Growth Hormone for Adults with Growth Hormone Deficiency Syndrome: Benefits and Risks. Int J Mol Sci 2018; 19:ijms19030893. [PMID: 29562611 PMCID: PMC5877754 DOI: 10.3390/ijms19030893] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 03/07/2018] [Accepted: 03/14/2018] [Indexed: 12/14/2022] Open
Abstract
Pharmacological treatment of growth hormone deficiency (GHD) in adults began in clinical practice more than 20 years ago. Since then, a great volume of experience has been accumulated on its effects on the symptoms and biochemical alterations that characterize this hormonal deficiency. The effects on body composition, muscle mass and strength, exercise capacity, glucose and lipid profile, bone metabolism, and quality of life have been fully demonstrated. The advance of knowledge has also taken place in the biological and molecular aspects of the action of this hormone in patients who have completed longitudinal growth. In recent years, several epidemiological studies have reported interesting information about the long-term effects of GH replacement therapy in regard to the possible induction of neoplasms and the potential development of diabetes. In addition, GH hormone receptor polymorphism could potentially influence GH therapy. Long-acting GH are under development to create a more convenient GH dosing profile, while retaining the excellent safety, efficacy, and tolerability of daily GH. In this article we compile the most recent data of GH replacement therapy in adults, as well as the molecular aspects that may condition a different sensitivity to this treatment.
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Abstract
Over the last three decades, short- and long-term observational studies, clinical trials, systematic reviews, and meta-analyses have provided relevant information on the efficacy and safety of growth hormone (GH) replacement therapy in adults with GH deficiency (AGHD). The knowledge acquired during this time has been compiled into different guidelines that offer clinicians an evidence-based, practical approach for the management of AGHD. There are, however, still open questions in some key areas in which recommendations are supported by only moderate or weak evidence. In the last recent years, the development of long-acting GH preparations has created new therapeutic possibilities by decreasing injection frequency, improving adherence and thereby potentially maximizing clinical outcomes. The aims of this review are to advance our understanding on the diagnosis and treatment of AGHD and to present an update and future perspectives on the use of long-acting GH preparations.
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Affiliation(s)
- Cesar Luiz Boguszewski
- Endocrine Division (SEMPR), Department of Internal Medicine, Federal University of Parana, Curitiba, Brazil
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17beta-estradiol promotes the odonto/osteogenic differentiation of stem cells from apical papilla via mitogen-activated protein kinase pathway. Stem Cell Res Ther 2014; 5:125. [PMID: 25403930 PMCID: PMC4446088 DOI: 10.1186/scrt515] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 10/29/2014] [Indexed: 12/12/2022] Open
Abstract
Introduction Estrogen plays an important role in the osteogenic differentiation of mesenchymal stem cells, while stem cells from apical papilla (SCAP) can contribute to the formation of dentin/bone-like tissues. To date, the effects of estrogen on the differentiation of SCAP remain unclear. Methods SCAP was isolated and treated with 10-7 M 17beta-estradiol (E2). The odonto/osteogenic potency and the involvement of mitogen-activated protein kinase (MAPK) signaling pathway were subsequently investigated by using methyl-thiazolyl-tetrazolium (MTT) assay, and other methods. Results MTT and flow cytometry results demonstrated that E2 treatment had no effect on the proliferation of SCAP in vitro, while alkaline phosphatase (ALP) assay and alizarin red staining showed that E2 can significantly promote ALP activity and mineralization ability in SCAP. Real-time reverse transcription polymerase chain reaction (RT-PCR) and western blot assay revealed that the odonto/osteogenic markers (ALP, DMP1/DMP1, DSPP/DSP, RUNX2/RUNX2, OSX/OSX and OCN/OCN) were significantly upregulated in E2-treated SCAP. In addition, the expression of phosphor-p38 and phosphor-JNK in these stem cells was enhanced by E2 treatment, as was the expression of the nuclear downstream transcription factors including phosphor-Sp1, phosphor-Elk-1, phosphor-c-Jun and phosphor-c-Fos, indicating the activation of MAPK signaling pathway during the odonto/osteogenic differentiation of E2-treated SCAP. Conversely, the differentiation of E2-treated SCAP was inhibited in the presence of MAPK specific inhibitors. Conclusions The ondonto/osteogenic differentiation of SCAP is enhanced by 10-7 M 17beta-estradiol via the activation of MAPK signaling pathway.
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