Human fetuin/alpha 2 HS glycoprotein in colloid and parenchymal cells in human fetal pituitary gland

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY GUIDELINES FOR MANAGEMENT OF GROWTH HORMONE DEFICIENCY IN ADULTS AND PATIENTS TRANSITIONING FROM PEDIATRIC TO ADULT CARE

Objective: The development of these guidelines is sponsored by the American Association of Clinical Endocrinologists (AACE) Board of Directors and American College of Endocrinology (ACE) Board of Trustees and adheres with published AACE protocols for the standardized production of clinical practice guidelines (CPG). Methods: Recommendations are based on diligent reviews of clinical evidence with transparent incorporation of subjective factors, according to established AACE/ACE guidelines for guidelines protocols. Results: The Executive Summary of this 2019 updated guideline contains 58 numbered recommendations: 12 are Grade A (21%), 19 are Grade B (33%), 21 are Grade C (36%), and 6 are Grade D (10%). These detailed, evidence-based recommendations allow for nuance-based clinical decision-making that addresses multiple aspects of real-world care of patients. The evidence base presented in the subsequent Appendix provides relevant supporting information for the Executive Summary recommendations. This update contains 357 citations of which 51 (14%) are evidence level (EL) 1 (strong), 168 (47%) are EL 2 (intermediate), 61 (17%) are EL 3 (weak), and 77 (22%) are EL 4 (no clinical evidence). Conclusion: This CPG is a practical tool that practicing endocrinologists and regulatory bodies can refer to regarding the identification, diagnosis, and treatment of adults and patients transitioning from pediatric to adult-care services with growth hormone deficiency (GHD). It provides guidelines on assessment, screening, diagnostic testing, and treatment recommendations for a range of individuals with various causes of adult GHD. The recommendations emphasize the importance of considering testing patients with a reasonable level of clinical suspicion of GHD using appropriate growth hormone (GH) cut-points for various GH-stimulation tests to accurately diagnose adult GHD, and to exercise caution interpreting serum GH and insulin-like growth factor-1 (IGF-1) levels, as various GH and IGF-1 assays are used to support treatment decisions. The intention to treat often requires sound clinical judgment and careful assessment of the benefits and risks specific to each individual patient. Unapproved uses of GH, long-term safety, and the current status of long-acting GH preparations are also discussed in this document. LAY ABSTRACT This updated guideline provides evidence-based recommendations regarding the identification, screening, assessment, diagnosis, and treatment for a range of individuals with various causes of adult growth-hormone deficiency (GHD) and patients with childhood-onset GHD transitioning to adult care. The update summarizes the most current knowledge about the accuracy of available GH-stimulation tests, safety of recombinant human GH (rhGH) replacement, unapproved uses of rhGH related to sports and aging, and new developments such as long-acting GH preparations that use a variety of technologies to prolong GH action. Recommendations offer a framework for physicians to manage patients with GHD effectively during transition to adult care and adulthood. Establishing a correct diagnosis is essential before consideration of replacement therapy with rhGH. Since the diagnosis of GHD in adults can be challenging, GH-stimulation tests are recommended based on individual patient circumstances and use of appropriate GH cut-points. Available GH-stimulation tests are discussed regarding variability, accuracy, reproducibility, safety, and contraindications, among other factors. The regimen for starting and maintaining rhGH treatment now uses individualized dose adjustments, which has improved effectiveness and reduced reported side effects, dependent on age, gender, body mass index, and various other individual characteristics. With careful dosing of rhGH replacement, many features of adult GHD are reversible and side effects of therapy can be minimized. Scientific studies have consistently shown rhGH therapy to be beneficial for adults with GHD, including improvements in body composition and quality of life, and have demonstrated the safety of short- and long-term rhGH replacement. Abbreviations: AACE = American Association of Clinical Endocrinologists; ACE = American College of Endocrinology; AHSG = alpha-2-HS-glycoprotein; AO-GHD = adult-onset growth hormone deficiency; ARG = arginine; BEL = best evidence level; BMD = bone mineral density; BMI = body mass index; CI = confidence interval; CO-GHD = childhood-onset growth hormone deficiency; CPG = clinical practice guideline; CRP = C-reactive protein; DM = diabetes mellitus; DXA = dual-energy X-ray absorptiometry; EL = evidence level; FDA = Food and Drug Administration; FD-GST = fixed-dose glucagon stimulation test; GeNeSIS = Genetics and Neuroendocrinology of Short Stature International Study; GH = growth hormone; GHD = growth hormone deficiency; GHRH = growth hormone-releasing hormone; GST = glucagon stimulation test; HDL = high-density lipoprotein; HypoCCS = Hypopituitary Control and Complications Study; IGF-1 = insulin-like growth factor-1; IGFBP = insulin-like growth factor-binding protein; IGHD = isolated growth hormone deficiency; ITT = insulin tolerance test; KIMS = Kabi International Metabolic Surveillance; LAGH = long-acting growth hormone; LDL = low-density lipoprotein; LIF = leukemia inhibitory factor; MPHD = multiple pituitary hormone deficiencies; MRI = magnetic resonance imaging; P-III-NP = procollagen type-III amino-terminal pro-peptide; PHD = pituitary hormone deficiencies; QoL = quality of life; rhGH = recombinant human growth hormone; ROC = receiver operating characteristic; RR = relative risk; SAH = subarachnoid hemorrhage; SDS = standard deviation score; SIR = standardized incidence ratio; SN = secondary neoplasms; T3 = triiodothyronine; TBI = traumatic brain injury; VDBP = vitamin D-binding protein; WADA = World Anti-Doping Agency; WB-GST = weight-based glucagon stimulation test.

Plasma biomarker proteins for detection of human growth hormone administration in athletes

Human growth hormone (GH) is a naturally occurring hormone secreted by the pituitary gland with anabolic and growth-promoting activities. Since an increased availability of recombinant GH (rGH) for the treatment of GH-deficient patients, GH has been abused in sports and it is prohibited. "GH-isoform" and "biomarkers" tests are currently available for detection of GH abuse in sports, however both methods suffer from shortcomings. Here, we report on a proteomic approach to search for novel protein biomarkers associated with rGH administration in non-elite athletes. In this study, participants received either placebo or rGH for 8 weeks, and were followed over a 6-week washout period. We used 2-D DIGE and iTRAQ LC-MS/MS analyses to expose rGH-dependent marker proteins. Eight rGH-dependent plasma proteins namely apolipoproptein-L1, alpha-HS-glycoprotein, vitamin D-binding protein, afamin, insulin-like growth factor-binding protein-3, insulin-like growth factor-binding protein-ALS, lumican and extracellular matrix proteins 1 were identified. Apolipoprotein L1 and alpha-HS-glycoprotein were validated by Western blots to confirm their identities and expression patterns in rGH- and placebo-treated subject cohorts. Independent confirmation of these putative GH-responsive biomarkers would be of value for clinical practices and may have sports anti-doping utility.

Multifunctional Roles for Serum Protein Fetuin-A in Inhibition of Human Vascular Smooth Muscle Cell Calcification

Vascular calcification predicts an increased risk for cardiovascular events/mortality in atherosclerosis, diabetes, and ESRD. Serum concentrations of alpha(2)-Heremens-Schmid glycoprotein, commonly referred to as fetuin-A, are reduced in ESRD, a condition associated with an elevated circulating calcium x phosphate product. Mice that lack fetuin-A exhibit extensive soft tissue calcification, which is accelerated on a mineral-rich diet, suggesting that fetuin-A acts to inhibit calcification systemically. Western blot and immunohistochemistry demonstrated that serum-derived fetuin-A co-localized with calcified human vascular smooth muscle cells (VSMC) in vitro and in calcified arteries in vivo. Fetuin-A inhibited in vitro VSMC calcification, induced by elevated concentrations of extracellular mineral ions, in a concentration-dependent manner. This was achieved in part through inhibition of apoptosis and caspase cleavage. Confocal microscopy and electron microscopy-immunogold demonstrated that fetuin-A was internalized by VSMC and concentrated in intracellular vesicles. Subsequently, fetuin-A was secreted via vesicle release from apoptotic and viable VSMC. Vesicles have previously been identified as the nidus for mineral nucleation. The presence of fetuin-A in vesicles abrogated their ability to nucleate basic calcium phosphate. In addition, fetuin-A enhanced phagocytosis of vesicles by VSMC. These observations provide evidence that the uptake of the serum protein fetuin-A by VSMC is a key event in the inhibition of vesicle-mediated VSMC calcification. Strategies aimed at maintaining normal circulating levels of fetuin-A may prove beneficial in patients with ESRD.

Cell-specific pituitary gene expression profiles after treatment with leukemia inhibitory factor reveal novel modulators for proopiomelanocortin expression

Leukemia inhibitory factor (LIF) mediates the hypothalamo-pituitary-adrenal stress response. Transgenic mice overexpressing LIF in the developing pituitary have altered pituitary differentiation with expansion of corticotropes, maintenance of Rathke's cleft cysts, and suppression of all other pituitary cell types. Affymetrix GeneChips were used to identify modulators of LIF effects in corticotrope (AtT-20) and somatolactotrope (GH(3)) cells. In addition to genes known to respond to LIF in corticotrope cells [e.g. suppressor of cytokine signaling-3 (SOCS-3), signal transducer and activator of transcription-3, SH2 domain-containing tyrosine phosphatase-1, and proopiomelanocortin (POMC)], corticotrope-specific changes were also observed for genes involved in glycolysis and gluconeogenesis, transcription factors, signaling molecules, and expressed sequence tags. Two transcription factors identified, CCAAT/enhancer-binding protein beta (C/EBPbeta) and glial cell-derived neurotrophic factor (GDNF)-inducible factor (GIF), dose-dependently induced expression of the rat POMC promoter when overexpressed in AtT-20 cells. LIF further induced POMC transcription with C/EBPbeta, but not with GIF. C/EBPbeta also induced expression of the SOCS-3 promoter that was further enhanced by cotreatment with LIF. However, GIF did not affect SOCS-3 expression. These results indicate that C/EBPbeta and GIF are downstream effectors of LIF corticotrope action. LIF also stimulates the expression of inhibitors of its actions, such as SOCS-3 and SH2 domain-containing tyrosine phosphatase-1. alpha(2)-HS-glycoprotein (AHSG)/fetuin, a secreted protein that antagonizes bone TGFbeta/bone morphogenic protein signaling, was induced by LIF in a signal transducer and activator of transcription-3-dependent fashion. Pretreatment with AHSG/fetuin blocked LIF-induced expression of the POMC promoter independently of SOCS-3. Thus, using GeneChips, C/EBPbeta and GIF have been identified as novel mediators and AHSG/fetuin as an inhibitor of LIF action in corticotropes.

Fetal fetuin selectively induces apoptosis in cancer cell lines and shows anti-cancer activity in tumor animal models

An apoptosis-inducing protein with molecular weight of 60 kDa has been purified from fetal bovine serum. The N-terminal amino acid sequence of this protein (e.g. I-P-L-D-P-V-A-G-Y-K) reveals that it is bovine fetuin, a fetal protein functioning to control embryogenesis. The apoptosis-inducing activity of fetuin is totally dependent on zinc. Depletion of zinc ion from fetuin or substitution of zinc ion by barium ion completely abolished the apoptosis-inducing activity of fetuin. Interestingly, while the fetuin isolated from fetal serum selectively induces apoptosis in cancer without affecting normal cells, the fetuin isolated from mature serum is completely inactive. This suggests that the biological activity of fetuin is under developmental regulation. In vivo, tumor animal model studies showed that fetuin enhanced survival by up to 141% in P388 leukemia animal model in mice. Fetuin was also found to inhibit prostate cancer formation in a PC-3 prostate cancer model in mice.