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Schilbach K, Bidlingmaier M. Pitfalls in the lab assessment of hypopituitarism. Rev Endocr Metab Disord 2024; 25:457-465. [PMID: 38609701 PMCID: PMC11162359 DOI: 10.1007/s11154-024-09881-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/01/2024] [Indexed: 04/14/2024]
Abstract
The diagnostic approach to hypopituitarism involves many disciplines. Clinical symptoms rarely are specific. Imaging techniques are helpful but cannot prove the specific functional defects. Therefore, the definitive diagnosis of pituitary insufficiency is largely based on laboratory tests. However, also laboratory methods come with inherent limitations, and it is essential for the clinician to know and recognize typical pitfalls. Most factors potentially impairing the quality of hormone measurements are introduced in the preanalytical phase, i.e. before the hormones are measured by the laboratory. For example, the timing of blood drawing with respect to circadian rhythm, stress, and medication can have an influence on hormone concentrations. During the actual analysis of the hormones, cross-reactions with molecules present in the sample presenting the same or similar epitopes than the intended analyte may affect immunoassays. Interference can also come from heterophilic or human anti-animal antibodies. Unexpected problems can also be due to popular nutritional supplements which interfere with the measurement procedures. An important example in this respect is the interference from biotin. It became only clinically visible when the use of this vitamin became popular among patients. The extreme serum concentrations reached when patients take it as a supplement can lead to incorrect measurements in immunoassays employing the biotin-streptavidin system. To some extent, hormone analyses using liquid chromatography mass spectrometry (LCMS) can overcome problems, although availability and cost-effectiveness of this method still imposes restrictions. In the post-analytical phase, appropriateness of reference intervals and cut-offs with respect to the specific analytical method used is of outmost importance. Furthermore, for interpretation, additional biological and pharmacological factors like BMI, age and concomitant diseases must be considered to avoid misinterpretation of the measured concentrations. It is important for the clinician and the laboratory to recognize when one or more laboratory values do not match the clinical picture. In an interdisciplinary approach, the search for the underlying cause should be initiated.
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Affiliation(s)
- Katharina Schilbach
- Medizinische Klinik und Poliklinik IV, LMU Klinikum, München, Germany
- Deggendorf Institute of Technology, Deggendorf, Germany
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Tausendfreund O, Bidlingmaier M, Martini S, Reif H, Rippl M, Schilbach K, Schmidmaier R, Drey M. The somatotroph pituitary gland function in high-aged multimorbid hospitalized patients with IGF-I deficiency. Pituitary 2024:10.1007/s11102-024-01406-y. [PMID: 38819617 DOI: 10.1007/s11102-024-01406-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/17/2024] [Indexed: 06/01/2024]
Abstract
PURPOSE It is unclear whether the age-related decline in the somatotropic axis stems from a reduced growth hormone (GH) production in the pituitary gland, or from a peripheral origin akin to an acquired GH resistance. With the help of a GHRH/arginine test, high-aged multimorbid hospitalized patients with IGF-I deficiency are to be tested to determine whether there is primarily a pituitary GH deficiency in the sense of a somatopause. METHODS Seventeen multimorbid patients (eleven men and six women) with a mean age of 82 years, with IGF-I concentrations below two standard deviations of 30-year-old men and women were identified. Patients suffered from a variety of common age-related stable diseases including coronary artery disease, chronic liver or kidney disease, chronic heart failure as well as acute conditions e.g., urosepsis or endocarditis. To assess the somatotropic axis they underwent a GHRH/arginine test. Results were evaluated using descriptive statistics. RESULTS In average, the peak concentration of GH after stimulation was 14.8 µg/L with a range from 2.76 to 47.4 µg/L. Taking into account both, gender and BMI (with a mean of 26.5 kg/m²) for each participant, the pituitary gland was adequately stimulated in 16 out of the 17 patients. No patient reported common side effects related to the GHRH/arginine test. CONCLUSION The somatotroph pituitary gland retains its secretory capacity in the advanced aged. Therefore, age does not seem to be the driving pacemaker for the functional decline of the somatotropic axis within the aged population.
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Affiliation(s)
| | - Martin Bidlingmaier
- Department of Medicine IV, University Hospital, LMU Munich, München, Germany
| | - Sebastian Martini
- Department of Medicine IV, University Hospital, LMU Munich, München, Germany
| | - Hannah Reif
- Department of Medicine IV, University Hospital, LMU Munich, München, Germany
| | - Michaela Rippl
- Department of Medicine IV, University Hospital, LMU Munich, München, Germany
| | - Katharina Schilbach
- Department of Medicine IV, University Hospital, LMU Munich, München, Germany
- Deggendorf Institute of Technology, Deggendorf, Germany
| | - Ralf Schmidmaier
- Department of Medicine IV, University Hospital, LMU Munich, München, Germany
| | - Michael Drey
- Department of Medicine IV, University Hospital, LMU Munich, München, Germany
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Paragliola RM, Carrozza C, Corsello SM, Salvatori R. The biochemical diagnosis of acromegaly: revising the role of measurement of IGF-I and GH after glucose load in 5 questions. Expert Rev Endocrinol Metab 2022; 17:205-224. [PMID: 35485763 DOI: 10.1080/17446651.2022.2069558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 04/20/2022] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Acromegaly is a rare disorder characterized by the excessive secretion of growth hormone (GH), mostly caused by pituitary adenomas. While in full-blown cases the diagnosis is easy to establish, milder cases are more challenging. Additionally, establishing whether full cure after surgery is reached may be difficult. AREAS COVERED In this article, we will review the challenges posed by the variability in measurements of GH and its main effector insulin-like growth factor I (IGF-I) due to both biological changes, co-morbidities, and assays variability. EXPERT OPINION Interpretation of GH and IGF-I assays is important in establishing an early diagnosis of acromegaly, in avoiding misdiagnosis, and in establishing if cure is achieved by surgery. Physicians should be familiar with the variables that affect measurements of these 2 hormones, and with the performance of the assays available in their practice.
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Affiliation(s)
- Rosa Maria Paragliola
- Unit of Endocrinology, Department of Translational Medicine and Surgery - Universita' Cattolica del Sacro Cuore, Fondazione Policlinico "Gemelli", IRCCS, Rome, Italy
| | - Cinzia Carrozza
- Unit of Chemistry, Biochemistry and Clinical Molecular Biology - Università Cattolica Del Sacro Cuore, Fondazione Policlinico "Gemelli," IRCCS, Rome, Italy
| | - Salvatore M Corsello
- Unit of Endocrinology, Department of Translational Medicine and Surgery - Universita' Cattolica del Sacro Cuore, Fondazione Policlinico "Gemelli", IRCCS, Rome, Italy
- UniCamillus-Saint Camillus International University of Health Sciences, Rome, Italy
| | - Roberto Salvatori
- Division of Endocrinology Diabetes and Metabolism and Pituitary Center, Johns Hopkins University, Baltimore MD, USA
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Goli P, Yazdi M, Heidari-Beni M, Kelishadi R. Growth Hormone Response to L-Arginine Alone and Combined with Different Doses of Growth Hormone-Releasing Hormone: A Systematic Review and Meta-Analysis. Int J Endocrinol 2022; 2022:8739289. [PMID: 36467462 PMCID: PMC9712012 DOI: 10.1155/2022/8739289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/02/2022] [Accepted: 11/03/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Arginine (ARG) can modulate growth hormone (GH) release by suppressing its endogenous inhibitory regulator, somatostatin. ARG also induces the release of the GH-releasing hormone (GHRH). This study aims to review the effects of L-arginine supplementation alone and combined with GHRH in different doses on GH secretion. METHODS In this systematic review and meta-analysis, an electronic literature search was conducted on Medline database (PubMed), Scopus, and Web of Science databases. All eligible studies were randomized clinical trials that reported the effects of ARG supplementation alone or with GHRH on GH levels. Mean difference (MD) and 95% confidence intervals (CI) were computed as the effect size. RESULTS Meta-analyses showed significant effects of ARG alone on GH release (MD = 10.07, 95% CI: 7.87, 12.28). Moreover, the response of GH was greater with ARG in combination with GHRH (MD = 24.96, 95% CI: 17.51, 32.42). There was no significant difference between the patients and healthy individuals and between oral and injection use of ARG. The systematic review revealed the important role of ARG in combination with other amino acids on GH secretion in patients with GH deficiency. CONCLUSION This study revealed that in GH-deficient individuals, high doses of ARG supplementation in combination with GHRH and/or other amino acids might have potential therapeutic effects on increasing GH concentrations. These findings propose that ARG supplementation can be considered as a potential stimulator in management of GH deficiency.
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Affiliation(s)
- Parvin Goli
- Department of Pediatrics, Child Growth and Development Research Center, Research Institute for Primordial Prevention of Non-Communicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Maryam Yazdi
- Department of Pediatrics, Child Growth and Development Research Center, Research Institute for Primordial Prevention of Non-Communicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Motahar Heidari-Beni
- Department of Nutrition, Child Growth and Development Research Center, Research Institute for Primordial Prevention of Non-Communicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Roya Kelishadi
- Department of Pediatrics, Child Growth and Development Research Center, Research Institute for Primordial Prevention of Non-Communicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran
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Garcia JM, Biller BMK, Korbonits M, Popovic V, Luger A, Strasburger CJ, Chanson P, Swerdloff R, Wang C, Fleming RR, Cohen F, Ammer N, Mueller G, Kelepouris N, Strobl F, Ostrow V, Yuen KCJ. Sensitivity and specificity of the macimorelin test for diagnosis of AGHD. Endocr Connect 2021; 10:76-83. [PMID: 33320108 PMCID: PMC7923131 DOI: 10.1530/ec-20-0491] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 12/14/2020] [Indexed: 12/18/2022]
Abstract
OBJECTIVE The macimorelin test is approved for the diagnosis of adult growth hormone deficiency (AGHD) based on its efficacy vs the insulin tolerance test (ITT). Macimorelin has a significant advantage over ITT in avoiding hypoglycemia. Analyses were conducted to determine whether macimorelin performance is affected by age, BMI, or sex, and evaluate its performance vs ITT over a range of GH cutpoints. DESIGN Post hoc analyses of data from a previous randomized phase 3 study included participants aged 18-66 years with BMI <37 kg/m2 and high (Group A), intermediate (Group B), or low (Group C) likelihood for AGHD based on pituitary history, and matched controls (Group D). METHODS Probability of AGHD was estimated using unadjusted, age-adjusted, BMI-adjusted, and sex-adjusted logistic models. Area under the curve (AUC) of the estimated receiver operating characteristic (ROC) curve (range, 0-1; 1 = perfect) was compared for adjusted vs unadjusted models. Separate analyses evaluated agreement, sensitivity, and specificity for macimorelin and ITT using cutpoints of 2.8, 4.0, 5.1, and 6.5 ng/mL. RESULTS For participants in Group A (n = 41) and Group D (n = 29), unadjusted, age-adjusted, BMI-adjusted, and sex-adjusted models had ROC AUCs (95% CIs) of 0.9924 (0.9807-1), 0.9924 (0.9807-1), 0.9916 (0.9786-1), and 0.9950 (0.9861-1), respectively. CONCLUSIONS Macimorelin performance was not meaningfully affected by age, BMI, or sex, indicating robustness for AGHD diagnosis. Of the 4 GH cutpoints evaluated, the cutpoint of 5.1 ng/mL provided maximal specificity (96%) and high sensitivity (92%) and was in good overall agreement with the ITT at the same cutpoint (87%).
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Affiliation(s)
- Jose M Garcia
- GRECC VA Puget Sound HCS/University of Washington, Seattle, Washington, USA
| | - Beverly M K Biller
- Massachusetts General Hospital, Neuroendocrine Unit, Boston, Massachusetts, USA
| | - Márta Korbonits
- Barts and the London School of Medicine, Queen Mary University of London, Endocrinology, London, UK
| | - Vera Popovic
- University of Belgrade, Medical Faculty, Belgrade, Serbia
| | - Anton Luger
- Division of Endocrinology and Metabolism, Medical University, General Hospital, Vienna, Austria
| | | | - Philippe Chanson
- Assistance Publique-Hôpitaux de Paris, Hôpital de Bicêtre, Service d’Endocrinologie et des Maladies de la Reproduction, Centre de Référence des Maladies Rares de l’Hypophyse, and Université Paris-Saclay, Univ. Paris-Sud, Inserm, Signalisation Hormonale, Physiopathologie Endocrinienne et Métabolique, Le Kremlin-Bicêtre, France
| | - Ronald Swerdloff
- The Lundquist Institute at Harbor-UCLA Medical Center, Torrance, California, USA
| | - Christina Wang
- The Lundquist Institute at Harbor-UCLA Medical Center, Torrance, California, USA
| | | | | | - Nicola Ammer
- Aeterna Zentaris GmbH, Frankfurt, Hessen, Germany
| | | | - Nicky Kelepouris
- Novo Nordisk Inc., Plainsboro, New Jersey, USA
- Correspondence should be addressed to N Kelepouris:
| | | | | | - Kevin C J Yuen
- University of Arizona College of Medicine and Creighton School of Medicine, Barrow Pituitary Center, Barrow Neurological Institute, Phoenix, Arizona, USA
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Schilbach K, Bidlingmaier M. Laboratory investigations in the diagnosis and follow-up of GH-related disorders. ARCHIVES OF ENDOCRINOLOGY AND METABOLISM 2019; 63:618-629. [PMID: 31939487 PMCID: PMC10522234 DOI: 10.20945/2359-3997000000192] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 10/12/2019] [Indexed: 11/23/2022]
Abstract
In addition to auxiological, clinical and metabolic features measurements of growth hormone (GH) and insulin-like growth factor I (IGF-I) complement our tools in diagnosis and follow-up of GH-related disorders. While comparably robust during the pre-analytical phase, measurement and interpretation of concentrations of both hormones can be challenging due to analytical issues and biological confounders. Assay methods differ in terms of antibody specificity, interference from binding proteins, reference preparations and sensitivity. GH assays have different specificity towards different GH-isoforms (e.g. 20 kDa GH, placental GH) and interference from the GH antagonist Pegvisomant. The efficacy to prevent binding protein interference is most important in IGF-I assays. Methodological differences between assays require that reference intervals and diagnostic cut-offs are assay-specific. Among biological variables, pubertal development and age are most relevant for IGF-I, making detailed reference intervals mandatory for interpretation. GH has pulsatile secretion and short half-life. Its concentration is modified by acute factors such as stress, exercise and sleep, but also by intake of oral estrogens and anthropometric factors (e.g. BMI). Other GH dependent biomarkers such as free IGF-I, IGF binding protein 3 (IGFBP 3) and acid labile subunit (ALS) have been proposed. Their concentrations largely mirror the information obtained through measurement of IGF-I, but their measurement can be helpful in particular situations. In this review, we describe the evolution of analytical methods to measure biomarkers of GH action, the impact of the methodological changes on laboratory results and the need to include biological variables in their interpretation. Arch Endocrinol Metab. 2019;63(6):618-29.
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Affiliation(s)
- Katharina Schilbach
- Medizinische Klinik und Poliklinik IVKlinikum der Universität MünchenMunichGermanyMedizinische Klinik und Poliklinik IV, Klinikum der Universität München, Munich, Germany
| | - Martin Bidlingmaier
- Medizinische Klinik und Poliklinik IVKlinikum der Universität MünchenMunichGermanyMedizinische Klinik und Poliklinik IV, Klinikum der Universität München, Munich, Germany
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Markkanen HM, Pekkarinen T, Hämäläinen E, Välimäki MJ, Alfthan H, Stenman UH. Gender has to be taken into account in diagnosing adult growth hormone deficiency by the GHRH plus arginine test. Growth Horm IGF Res 2017; 35:52-56. [PMID: 28755537 DOI: 10.1016/j.ghir.2017.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 06/29/2017] [Accepted: 07/11/2017] [Indexed: 11/15/2022]
Abstract
OBJECTIVE Data on the effect of gender on the interpretation of the GHRH plus arginine stimulation test (GHRH+ARG test) is controversial. We validated the GHRH+ARG stimulation test in control subjects and patients with organic or idiopathic pituitary disease and a suspicion of adult growth hormone deficiency (AGHD) using the Immulite 2000 XPi GH assay. DESIGN We studied 126 apparently healthy adults (median age 38.8years) and 34 patients with a suspicion of AGHD (median age 42.2years). Identification of AGHD with the GHRH+ARG test was investigated with commonly accepted BMI-related consensus cut-off limits for peak GH concentrations. Serum samples collected during the GHRH+ARG test were analysed for GH in 2014-2015. Serum IGF-1 concentrations were studied as a reference. RESULTS In 14 of 65 (22%) control males the GH peak value was below the BMI-related cut-off limits for GH sufficiency indicating a false diagnosis of AGHD. All control females had a normal GHRH+ARG response. Median peak GH response was significantly (p<0.001) higher in female (39.3μg/L) than in male controls (21μg/L). According to consensus cut-offs all but one young female patient had a deficient response compatible with a diagnosis of AGHD. CONCLUSIONS The GH response to stimulation by GHRH+ARG is gender-dependent, being lower in healthy males than in females. Gender should be considered when defining cut-off limits for peak GH concentrations in the GHRH+ARG test. The presently used BMI-related cut-off levels will lead to a significant misclassification of males as GH deficient.
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Affiliation(s)
| | - Tuula Pekkarinen
- HUS Abdominal Centre, Endocrinology, Helsinki University Hospital, Helsinki, Finland
| | - Esa Hämäläinen
- Helsinki University Central Hospital, HUSLAB, Helsinki, Finland; Department of Clinical Chemistry, Helsinki University Central Hospital, Helsinki, Finland
| | - Matti J Välimäki
- HUS Abdominal Centre, Endocrinology, Helsinki University Hospital, Helsinki, Finland
| | - Henrik Alfthan
- Helsinki University Central Hospital, HUSLAB, Helsinki, Finland
| | - Ulf-Håkan Stenman
- Department of Clinical Chemistry, Helsinki University Central Hospital, Helsinki, Finland
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