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Liu Z, Zhao X, Liu Y, Shi L, Wu L, Yuan H, Jin Y. Development of an insulin-like growth factor-1 certified reference material by SI-traceable isotope-dilution mass spectrometry. Talanta 2024; 273:125812. [PMID: 38452589 DOI: 10.1016/j.talanta.2024.125812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/29/2024] [Accepted: 02/17/2024] [Indexed: 03/09/2024]
Abstract
In this study, an insulin-like growth factor-1 (IGF-1) certified reference material (CRM) was developed by the National Institute of Metrology (NIM), and two different principles for evaluating the IGF-1 CRM were established. After optimisation of the acid hydrolysis conditions (110 °C, 36 h), quantitative determination of peptide purity, and chromatographic separation and mass spectrometric detection, amino acid analysis-based high-performance liquid chromatography combined with isotope-dilution tandem mass spectrometry (AAA-HPLC-IDMS/MS) and peptide analysis-based HPLC-IDMS/MS (Peptide-HPLC-IDMS/MS) were used for certified value assignment; the results obtained were 136.28 and 135.01 μg/g, respectively, which were in good agreement. These results were subjected to the normal distribution test, outlier test, and method consistency test. The homogeneity and stability of the reference materials were also examined, and the uncertainty introduced in the experimental process was calculated. The final certified value was (136 ± 15) μg g-1 (k = 2). The CRM was found to be stable for at least six months when stored at -70 °C and for 7 d when stored at higher temperatures (-20 °C, 4 °C, 25 °C, or 40 °C). The CRM is expected to be used as a primary calibrator for quality control in biopharmaceutical production and clinical diagnostics.
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Affiliation(s)
- Zihan Liu
- National Institute of Metrology, Beijing, China; Department of Clinical Laboratory, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Xu Zhao
- National Institute of Metrology, Beijing, China
| | - Yahui Liu
- National Institute of Metrology, Beijing, China
| | - Lianhua Shi
- National Institute of Metrology, Beijing, China
| | - Liqing Wu
- National Institute of Metrology, Beijing, China
| | - Hui Yuan
- Department of Clinical Laboratory, Beijing Anzhen Hospital, Capital Medical University, Beijing, China.
| | - Youxun Jin
- National Institute of Metrology, Beijing, China.
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Vilar L, Naves LA, Martins MRA, Ribeiro-Oliveira A. "Micromegaly": Acromegaly with apparently normal GH, an entity on its own? Best Pract Res Clin Endocrinol Metab 2024; 38:101878. [PMID: 38519400 DOI: 10.1016/j.beem.2024.101878] [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] [Indexed: 03/24/2024]
Abstract
A small proportion of the patients with acromegaly present with apparently normal basal GH levels and suppressible GH levels despite increased IGF-1 levels, a pattern called micromegaly by some authors. Whether this pattern represents a distinct entity or is just an expression of acromegaly in its early stages is still a matter of debate. Nevertheless, these patients have some peculiar characteristics such as being more likely older and male, mostly harbour microadenomas or small macroadenomas, and have lower IGF-1 and postglucose GH levels. Even though, the frequency and severity of clinical signs and comorbidities are similar to those of patients with classic acromegaly. In conclusion, micromegaly seems to be a distinct clinical entity with a different biological behavior characterized by a low GH output.
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Affiliation(s)
- Lucio Vilar
- Federal University of Pernambuco Medical School, Recife, PE, Brazil.
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Motorykin I, Mu J, Miller BS, Li A, Clarke NJ, McPhaul MJ, Wu Z. Detection rate of IGF-1 variants and their implication to protein binding: study of over 240,000 patients. Clin Chem Lab Med 2024; 62:484-492. [PMID: 37811857 DOI: 10.1515/cclm-2023-0709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/25/2023] [Indexed: 10/10/2023]
Abstract
OBJECTIVES To determine the detection rate of IGF-1 variants in a clinical population and assess their implications. METHODS IGF-1 variants were detected based on their predicted mass-to-charge ratios. Most variants were distinguished by their isotopic distribution and relative retention times. A67T and A70T were distinguished with MS/MS. Patient specimens with a detected variant were de-identified for DNA sequencing to confirm the polymorphism. RESULTS Of the 243,808 patients screened, 1,099 patients containing IGF-1 variants were identified (0.45 %, or 4,508 occurrences per million). Seven patients were identified as homozygous or double heterozygous. Majority of variants (98 %) had amino acid substitutions located at the C-terminus (A62T, P66A, A67S, A67V, A67T, A70T). Isobaric variants A38V and A67V were detected more frequently in children than in adults. Six previously unreported variants were identified: Y31H, S33P, T41I, R50Q, R56K, and A62T. Compared with the overall population, z-score distribution of patients with IGF-1 variants was shifted toward negative levels (median z-score -1.4); however, it resembled the overall population when corrected for heterozygosity. Chromatographic peak area of some variants differed from that of the WT IGF-1 present in the same patient. CONCLUSIONS In the IGF-1 test reports by LC-MS, the concentrations only account for half the total IGF-1 for patients with heterozygous IGF-1 variants. An IGF-1 variant may change the binding to its receptor and/or its binding proteins, affecting its activity and half-life in circulation. Variants located in or close to the C-domain may be pathogenic. Cross-species sequence comparison indicates that A38V and A70T may have some degree of pathogenicity.
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Affiliation(s)
- Ievgen Motorykin
- Quest Diagnostics Nichols Institute, San Juan Capistrano, CA, USA
| | - Jianying Mu
- Quest Diagnostics Nichols Institute, San Juan Capistrano, CA, USA
| | - Bradley S Miller
- University of Minnesota Medical School, MHealth Fairview Masonic Children's Hospital, Minneapolis, MN, USA
| | - Allison Li
- Quest Diagnostics Nichols Institute, San Juan Capistrano, CA, USA
| | - Nigel J Clarke
- Quest Diagnostics Nichols Institute, San Juan Capistrano, CA, USA
| | | | - Zengru Wu
- Quest Diagnostics Nichols Institute, San Juan Capistrano, CA, USA
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Giustina A, Biermasz N, Casanueva FF, Fleseriu M, Mortini P, Strasburger C, van der Lely AJ, Wass J, Melmed S. Consensus on criteria for acromegaly diagnosis and remission. Pituitary 2024; 27:7-22. [PMID: 37923946 PMCID: PMC10837217 DOI: 10.1007/s11102-023-01360-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/17/2023] [Indexed: 11/06/2023]
Abstract
PURPOSE The 14th Acromegaly Consensus Conference was convened to consider biochemical criteria for acromegaly diagnosis and evaluation of therapeutic efficacy. METHODS Fifty-six acromegaly experts from 16 countries reviewed and discussed current evidence focused on biochemical assays; criteria for diagnosis and the role of imaging, pathology, and clinical assessments; consequences of diagnostic delay; criteria for remission and recommendations for follow up; and the value of assessment and monitoring in defining disease progression, selecting appropriate treatments, and maximizing patient outcomes. RESULTS In a patient with typical acromegaly features, insulin-like growth factor (IGF)-I > 1.3 times the upper limit of normal for age confirms the diagnosis. Random growth hormone (GH) measured after overnight fasting may be useful for informing prognosis, but is not required for diagnosis. For patients with equivocal results, IGF-I measurements using the same validated assay can be repeated, and oral glucose tolerance testing might also be useful. Although biochemical remission is the primary assessment of treatment outcome, biochemical findings should be interpreted within the clinical context of acromegaly. Follow up assessments should consider biochemical evaluation of treatment effectiveness, imaging studies evaluating residual/recurrent adenoma mass, and clinical signs and symptoms of acromegaly, its complications, and comorbidities. Referral to a multidisciplinary pituitary center should be considered for patients with equivocal biochemical, pathology, or imaging findings at diagnosis, and for patients insufficiently responsive to standard treatment approaches. CONCLUSION Consensus recommendations highlight new understandings of disordered GH and IGF-I in patients with acromegaly and the importance of expert management for this rare disease.
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Affiliation(s)
- Andrea Giustina
- San Raffaele Vita-Salute University and IRCCS Hospital, Milan, Italy
| | | | | | | | - Pietro Mortini
- San Raffaele Vita-Salute University and IRCCS Hospital, Milan, Italy
| | | | | | | | - Shlomo Melmed
- Cedars-Sinai Medical Center, 8700 Beverly Blvd, NT 2015, Los Angeles, CA, 90048, USA.
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Ezra S, Winstone TML, Singh R, Orton DJ. Agreement of LC-MS assays for IGF-1 traceable to NIST and WHO standards permits harmonization of reference intervals between laboratories. Clin Biochem 2023; 116:75-78. [PMID: 37031902 DOI: 10.1016/j.clinbiochem.2023.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 03/27/2023] [Accepted: 04/06/2023] [Indexed: 04/11/2023]
Abstract
OBJECTIVES In this study, we aimed to determine the feasibility of transferring IGF-1 reference intervals between two liquid chromatography-mass spectrometry assays with distinct assay formats and calibration traceability. DESIGN AND METHODS To adopt a reference interval (RI) for our new assay we have conducted RI transference and verification studies according to the CLSI C28-A3 and EP9c guidelines. Specifically, the analytical agreement between the assays was evaluated using the linear model and the appropriateness of the linear model for RI transference was assessed using Deming regression, correlation coefficients, Q-Q plot, difference plot and studentized residues for the LC-MS/MS against DiaSorin LiaisonXL IGF-1 immunoassay and the liquid chromatography-high resolution mass spectrometry (LC-MS/HRMS) IGF-1 assay. Both Diasorin immunoassay and LC-MS/HRMS assays are traceable to WHO, 02/254. RESULTS Our study showed a strong correlation (R2>0.93) and agreement (slope=1.006, negligible intercept) between LC-MS/MS and LC-MS/HRMS regardless of their traceability and all statistical criteria were met per CLSI guidelines. Conversely, while the LC-MS/MS and Diasorin immunoassay results showed a strong correlation (R2>0.97, slope=1.055), they failed to meet all statistical criteria for RI transference due to the bias (-44.91) and non-normal distribution of the residues. The RI verification study showed that 95% of the local LC-MS results fell within the RIs transferred from the reference LC-MS method, thus meeting CLSI C28-A3 guidelines and permitting the transference of the reference LC-MS RIs. CONCLUSIONS Taken together, this study provides data to suggest excellent agreement between assays traceable to distinct reference standards for IGF-1.
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Affiliation(s)
- Sally Ezra
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB, Canada; Alberta Precision Laboratories, Calgary, AB, Canada
| | | | - R Singh
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Dennis J Orton
- Department of Pathology and Laboratory Medicine, University of Calgary, Calgary, AB, Canada; Alberta Precision Laboratories, Calgary, AB, Canada.
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Bias in IGF-1 concentrations and interpretation across three different clinical laboratory assays. Clin Biochem 2022; 108:14-19. [PMID: 35772500 DOI: 10.1016/j.clinbiochem.2022.06.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 06/17/2022] [Accepted: 06/24/2022] [Indexed: 11/22/2022]
Abstract
In this study, we compared the DiaSorin LiaisonXL IGF-1 immunoassay to both the Roche Elecsys IGF-1 immunoassay and to the liquid chromatography-high resolution mass spectrometry (LC-MS) IGF-1 assay. Our study shows a constant positive bias in DiaSorin compared to the Roche immunoassay (mean 42 μg/L, 24%), and a proportional positive bias in DiaSorin compared to the LC-MS method (mean 49 μg/L, 29%). Further, we demonstrate the potential clinical impact of this bias by evaluating 43 adult samples, collected over a 2-month period, which were shown to be discrepant based on a chart review. Despite the positive analytical bias in the Diasorin assay compared to the LC-MS assay, the Diasorin assay upper reference limits were lower than those of the LC-MS assay. This effect caused nine out of forty-three samples to show falsely elevated results when they were clinically diagnosed as negative for acromegaly. Discussed in the context of previous literature, our findings emphasize the importance of adjusting reference intervals for IGF-1 assays based on the clinical needs of a patient population.
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Cocchiara F, Campana C, Nista F, Corica G, Ceraudo M, Milioto A, Criminelli Rossi D, Zona G, Ferone D, Gatto F. Evaluation of acromegaly treatment direct costs with respect to biochemical control and follow-up length. Pituitary 2022; 25:246-257. [PMID: 34757473 DOI: 10.1007/s11102-021-01193-w] [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] [Accepted: 10/30/2021] [Indexed: 11/29/2022]
Abstract
PURPOSE Acromegaly is a severe chronic endocrine disease. Achieving biochemical control often needs a multimodal treatment approach, including prolonged medical treatment. Aim of the study is to evaluate the burden of treatment direct costs with respect to the different therapeutic strategies, disease control, and follow-up length. METHODS Single center retrospective study on 73 acromegaly patients. Costs of acromegaly treatments were computed based on a detailed revision of patients' clinical charts. RESULTS Median total treatment cost/patient was €47,343 during the entire follow-up (8 years), while median treatment cost/patient/year was €6811. The majority of patients received medical therapy (71/73, 97.3%). Median cost for first-line medical treatment (first-generation somatostatin receptor ligands) was lower compared to second-line treatments (pegvisomant monotherapy or combination therapies), considering both total (€22,824 vs €76,140; p < 0.001), and yearly cost/patient (€4927 vs €9161; p < 0.001). Sixty patients (82.2%) reached biochemical control at last follow-up (IGF-1 ≤ 1 xULN). The percentage of patients treated with first- or second-line medical therapies was comparable between controlled and uncontrolled patients (p = 1.000), and the yearly cost/patient did not significantly differ between the two groups (€6936 vs €6680; p = 0.829). Follow-up duration was significantly longer in controlled patients compared to the uncontrolled ones (8.7 vs 3.5 years; p = 0.019). CONCLUSIONS Direct costs for the management of acromegaly have a significant burden on the healthcare systems. However, more than 80% of our patients reached biochemical control using multimodal approaches. Treatment modalities and yearly costs did not significantly differ between controlled and uncontrolled patients, while follow-up length represented a major determinant of biochemical outcome.
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Affiliation(s)
- Francesco Cocchiara
- Endocrinology Unit, Department of Internal Medicine and Medical Specialties (DIMI) and Centre of Excellence for Biomedical Research (CEBR), University of Genoa, Genoa, Italy
- Endocrinology Unit, IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi, 10, 16132, Genoa, Italy
| | - Claudia Campana
- Endocrinology Unit, Department of Internal Medicine and Medical Specialties (DIMI) and Centre of Excellence for Biomedical Research (CEBR), University of Genoa, Genoa, Italy
| | - Federica Nista
- Endocrinology Unit, Department of Internal Medicine and Medical Specialties (DIMI) and Centre of Excellence for Biomedical Research (CEBR), University of Genoa, Genoa, Italy
| | - Giuliana Corica
- Endocrinology Unit, Department of Internal Medicine and Medical Specialties (DIMI) and Centre of Excellence for Biomedical Research (CEBR), University of Genoa, Genoa, Italy
| | - Marco Ceraudo
- Neurosurgery Unit, Department of Neurosciences (DINOGMI), IRCCS Ospedale Policlinico San Martino, University of Genoa, Genoa, Italy
| | - Angelo Milioto
- Endocrinology Unit, Department of Internal Medicine and Medical Specialties (DIMI) and Centre of Excellence for Biomedical Research (CEBR), University of Genoa, Genoa, Italy
| | - Diego Criminelli Rossi
- Neurosurgery Unit, Department of Neurosciences (DINOGMI), IRCCS Ospedale Policlinico San Martino, University of Genoa, Genoa, Italy
| | - Gianluigi Zona
- Neurosurgery Unit, Department of Neurosciences (DINOGMI), IRCCS Ospedale Policlinico San Martino, University of Genoa, Genoa, Italy
| | - Diego Ferone
- Endocrinology Unit, Department of Internal Medicine and Medical Specialties (DIMI) and Centre of Excellence for Biomedical Research (CEBR), University of Genoa, Genoa, Italy
- Endocrinology Unit, IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi, 10, 16132, Genoa, Italy
| | - Federico Gatto
- Endocrinology Unit, IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi, 10, 16132, Genoa, Italy.
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Donegan D, Algeciras-Schimnich A, Ashrafzadeh-Kian S, Erickson D. Insulin-Like Growth Factor 1 in the Early Postoperative Assessment of Acromegaly. Am J Clin Pathol 2022; 157:595-601. [PMID: 34665848 DOI: 10.1093/ajcp/aqab168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/31/2021] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Assessment of surgical outcome in acromegaly is typically recommended at 3 to 6 months following surgery. The purpose of this study was to determine if insulin-like growth factor 1 (IGF-1) concentrations at 6 weeks were equally predictive of surgical outcomes compared with IGF-1 concentrations at 3 to 6 months postoperatively applying newer IGF-1 assays. METHODS Retrospective review of patients with newly diagnosed acromegaly who had surgery between 2013 and 2020 and had postoperative IGF-1 measured by 6 weeks and 3 to 6 months. RESULTS At 6 weeks, 20 (35%) of the total 57 had normal IGF-1 and became abnormal in 1 at 3 to 6 months, whereas 37 (65%) of 57 had abnormal IGF-1 concentrations at 6 weeks, which normalized in 1 patient by 3 to 6 months. In patients who changed clinical status, IGF-1 at 6 weeks was within ±0.1-fold of normal. Although a difference was seen between median IGF-1 concentrations (286 vs 267 ng/mL, P = .009) at 6 weeks and 3 to 6 months, the mean reduction was small (-19.9 ng/mL). CONCLUSIONS Compared with 3 to 6 months, use of IGF-1 at 6 weeks was associated with a change in clinical status in 3.5% of patients. Therefore, in most patients, IGF-1 at 6 weeks can be used to assess clinical outcome via newer assays.
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Affiliation(s)
- Diane Donegan
- Department of Endocrinology Diabetes and Metabolism, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Endocrinology, Diabetes and Metabolism, Mayo College of Medicine, Rochester, MN, USA
| | | | | | - Dana Erickson
- Department of Endocrinology, Diabetes and Metabolism, Mayo College of Medicine, Rochester, MN, USA
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Ershadinia N, Tritos NA. Diagnosis and Treatment of Acromegaly: An Update. Mayo Clin Proc 2022; 97:333-346. [PMID: 35120696 DOI: 10.1016/j.mayocp.2021.11.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 10/16/2021] [Accepted: 11/04/2021] [Indexed: 01/01/2023]
Abstract
Acromegaly is typically caused by a growth hormone-secreting pituitary adenoma, driving excess secretion of insulin-like growth factor 1. Acromegaly may result in a variety of cardiovascular, respiratory, endocrine, metabolic, musculoskeletal, and neoplastic comorbidities. Early diagnosis and adequate treatment are essential to mitigate excess mortality associated with acromegaly. PubMed searches were conducted using the keywords growth hormone, acromegaly, pituitary adenoma, diagnosis, treatment, pituitary surgery, medical therapy, and radiation therapy (between 1981 and 2021). The diagnosis of acromegaly is confirmed on biochemical grounds, including elevated serum insulin-like growth factor 1 and lack of growth hormone suppression after glucose administration. Pituitary magnetic resonance imaging is advised in patients with acromegaly to identify an underlying pituitary adenoma. Transsphenoidal pituitary surgery is generally first-line therapy for patients with acromegaly. However, patients with larger and invasive tumors (macroadenomas) are often not in remission postoperatively. Medical therapies, including somatostatin receptor ligands, cabergoline, and pegvisomant, can be recommended to patients with persistent disease after surgery. Select patients may also be candidates for preoperative medical therapy. In addition, primary medical therapy has a role for patients without mass effect on the optic chiasm who are unlikely to be cured by surgery. Clinical, endocrine, imaging, histologic, and molecular markers may help predict the response to medical therapy; however, confirmation in prospective studies is needed. Radiation therapy is usually a third-line option and is increasingly administered by a variety of stereotactic techniques. An improved understanding of the pathogenesis of acromegaly may ultimately lead to the design of novel, efficacious therapies for this serious condition.
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Affiliation(s)
- Nazanin Ershadinia
- Neuroendocrine Unit and Neuroendocrine and Pituitary Tumor Clinical Center, Massachusetts General Hospital, Boston
| | - Nicholas A Tritos
- Neuroendocrine Unit and Neuroendocrine and Pituitary Tumor Clinical Center, Massachusetts General Hospital, Boston; Harvard Medical School, Boston, MA.
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Сахнова ЕЕ, Пржиялковская ЕГ, Белая ЖЕ, Мельниченко ГА. [Discordant parameters of insulin-like growth factor 1 and growth hormone in the diagnosis and monitoring of acromegaly]. PROBLEMY ENDOKRINOLOGII 2021; 68:40-48. [PMID: 35262296 PMCID: PMC9761869 DOI: 10.14341/probl12791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 12/16/2021] [Accepted: 12/16/2021] [Indexed: 01/09/2023]
Abstract
Acromegaly is a rare endocrine disorder associated with multiple complications and increased mortality. Timely diagnosis and adequate treatment can bring the life expectancy of patients with acromegaly closer to the general population level. The tests for the diagnosis of acromegaly are measurement of both serum GH, and GH after oral glucose administration; serum insulin-like growth factor-1 (IGF-1). However, in clinical practice, up to 39% of patients with discordant results are found. The patients with discordant GH and IGF-1levels, are the most difficult to manage. This review discusses the prevalence of discordant GH and IGF-1 outcomes in patients with acromegaly; factors causing this discrepancy; the impact of hormone levels on treatment outcomes. Although endocrinologists are used to dealing with this discrepancy in clinical practice for many years, discordant patients'outcome remains uncertain and undefined The optimal treatment should be individually tailored for each patient, taking into account all clinical parameters.
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Affiliation(s)
- Е. Е. Сахнова
- Национальный медицинский исследовательский центр эндокринологии
| | | | - Ж. Е. Белая
- Национальный медицинский исследовательский центр эндокринологии
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Motorykin I, Li H, Clarke NJ, McPhaul MJ, Wu Z. Isotopic Peak Index, Relative Retention Time, and Tandem MS for Automated High Throughput IGF-1 Variants Identification in a Clinical Laboratory. Anal Chem 2021; 93:11836-11842. [PMID: 34461729 DOI: 10.1021/acs.analchem.1c02566] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Measuring insulin-like growth factor-1 (IGF-1) is useful for assessing and managing growth-related disorders, such as acromegaly and growth hormone deficiency. High-resolution liquid chromatography-mass spectrometry (LC-MS) is used for measuring IGF-1 due to its molecular specificity, quantitative performance, well-characterized reference materials, and detailed age/sex-specific reference intervals. However, polymorphisms in the IGF1 gene may cause mass shifts in the polypeptide, which can impede quantitation and cause errors in clinical interpretation. We (1) developed a concept of "isotopic peak index", which allows simultaneous monitoring of 15 IGF-1 variants by using only four m/z ratios; (2) developed a "relative retention time" parameter that allows distinction of previously unresolved variants; and (3) utilized tandem mass spectrometry (MS/MS) to distinguish between the most common pair of variants: isobaric A67T and A70T. All methods were validated with DNA sequencing. This approach identified six variants from the ExAC database, P66A, A67S, S34N, A38 V, A67T, and A70T; two previously reported V44M and A67V variants; and discovered six unreported variants, Y31H, S33P, R50Q, R56K, T41I, and A62T. Major improvements in our workflow include enhanced automation, avoiding detailed manual calculations that are prone to human error, and the ability to monitor more, and discover new, IGF-1 variants. The workflow provides a profile of a patient's IGF-1 status and can be used to explore genotype-phenotype relationships in IGF-1 variants.
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Affiliation(s)
- Ievgen Motorykin
- Quest Diagnostics, 33608 Ortega Highway, San Juan Capistrano, California 92690, United States
| | - Hua Li
- Quest Diagnostics, 33608 Ortega Highway, San Juan Capistrano, California 92690, United States
| | - Nigel J Clarke
- Quest Diagnostics, 33608 Ortega Highway, San Juan Capistrano, California 92690, United States
| | - Michael J McPhaul
- Quest Diagnostics, 33608 Ortega Highway, San Juan Capistrano, California 92690, United States
| | - Zengru Wu
- Quest Diagnostics, 33608 Ortega Highway, San Juan Capistrano, California 92690, United States
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12
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Akirov A, Masri-Iraqi H, Dotan I, Shimon I. The Biochemical Diagnosis of Acromegaly. J Clin Med 2021; 10:jcm10051147. [PMID: 33803429 PMCID: PMC7967116 DOI: 10.3390/jcm10051147] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/03/2021] [Accepted: 03/05/2021] [Indexed: 12/20/2022] Open
Abstract
Background: The diagnosis of acromegaly still poses a clinical challenge, and prolonged diagnostic delay is common. The most important assays for the biochemical diagnosis and management of acromegaly are growth hormone (GH) and insulin-like growth factor-1 (IGF-1). Objective: Discuss the role of IGF-1, basal serum GH, and nadir GH after oral glucose tolerance test (OGTT) for the diagnosis, management, and treatment of patients with acromegaly. Methods: We performed a narrative review of the published data on the biochemical diagnosis and monitoring of acromegaly. An English-language search for relevant studies was conducted on PubMed from inception to 1 January 2021. The reference lists of relevant studies were also reviewed. Results: Serum IGF-1 levels, basal GH values, and nadir GH after OGTT play a major role in the diagnosis, management, and treatment of patients with acromegaly. Measurement of IGF-1 levels is the key factor in the diagnosis and monitoring of acromegaly, but basal and nadir GH following OGTT are also important. However, several factors may significantly influence the concentrations of these hormones, including assay methods, physiologic and pathologic factors. In some cases, discordant GH and IGF-1 levels may be challenging and usually requires additional data and monitoring. Conclusion: New GH and IGF-1 standards are much more precise and provide more accurate tools to diagnose and monitor patients with acromegaly. However, all these biochemical tools have their limitations, and these should be taken under consideration, along with the history, clinical features and imaging studies, when assessing patients for acromegaly.
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Affiliation(s)
- Amit Akirov
- Institute of Endocrinology, Beilinson Hospital, 49100 Petach Tikva, Israel; (H.M.-I.); (I.D.); (I.S.)
- Correspondence: ; Tel.: +972-524650760
| | - Hiba Masri-Iraqi
- Institute of Endocrinology, Beilinson Hospital, 49100 Petach Tikva, Israel; (H.M.-I.); (I.D.); (I.S.)
- Sackler School of Medicine, Tel Aviv University, 39040 Tel Aviv, Israel
| | - Idit Dotan
- Institute of Endocrinology, Beilinson Hospital, 49100 Petach Tikva, Israel; (H.M.-I.); (I.D.); (I.S.)
- Sackler School of Medicine, Tel Aviv University, 39040 Tel Aviv, Israel
| | - Ilan Shimon
- Institute of Endocrinology, Beilinson Hospital, 49100 Petach Tikva, Israel; (H.M.-I.); (I.D.); (I.S.)
- Sackler School of Medicine, Tel Aviv University, 39040 Tel Aviv, Israel
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Campana C, Cocchiara F, Corica G, Nista F, Arvigo M, Amarù J, Rossi DC, Zona G, Ferone D, Gatto F. Discordant GH and IGF-1 Results in Treated Acromegaly: Impact of GH Cutoffs and Mean Values Assessment. J Clin Endocrinol Metab 2021; 106:789-801. [PMID: 33236108 DOI: 10.1210/clinem/dgaa859] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Indexed: 11/19/2022]
Abstract
CONTEXT Discordant growth hormone (GH) and insulin-like growth factor-1 (IGF-1) values are frequent in acromegaly. OBJECTIVE To evaluate the impact of different GH cutoffs on discordance rate. To investigate whether the mean of consecutive GH measurements impacts discordance rate when matched to the last available IGF-1 value. DESIGN Retrospective study. SETTING Referral center for pituitary diseases. PATIENTS Ninety acromegaly patients with at least 3 consecutive evaluations for GH and IGF-1 using the same assay in the same laboratory (median follow-up 13 years). INTERVENTIONS Multimodal treatment of acromegaly. MAIN OUTCOME MEASURES Single fasting GH (GHf) and IGF-1 (IGF-1f). Mean of 3 GH measurements (GHm), collected during consecutive routine patients' evaluations. RESULTS At last evaluation GHf values were 1.99 ± 2.79 µg/L and age-adjusted IGF-1f was 0.86 ± 0.44 × upper limit of normality (mean ± SD). The discordance rate using GHf was 52.2% (cutoff 1 µg/L) and 35.6% (cutoff 2.5 µg/L) (P = 0.025). "High GH" discordance was more common for GHf <1.0 µg/L, while "high IGF-1" was predominant for GHf <2.5 µg/L (P < 0.0001). Using GHm mitigated the impact of GH cutoffs on discordance (GHm <1.0 µg/L: 43.3%; GHm <2.5 µg/L: 38.9%; P = 0.265). At receiver-operator characteristic curve (ROC) analysis, both GHf and GHm were poor predictors of IGF-1f normalization (area under the curve [AUC] = 0.611 and AUC = 0.645, respectively). The prevalence of disease-related comorbidities did not significantly differ between controlled, discordant, and active disease patients. DISCUSSION GH/IGF-1 discordance strongly depends on GH cutoffs. The use of GHm lessen the impact of GH cutoffs. Measurement of fasting GH levels (both GHf and GHm) is a poor predictor of IGF-1f normalization in our cohort.
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Affiliation(s)
- Claudia Campana
- Endocrinology Unit, Department of Internal Medicine and Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
- Endocrinology Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Francesco Cocchiara
- Endocrinology Unit, Department of Internal Medicine and Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
- Endocrinology Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Giuliana Corica
- Endocrinology Unit, Department of Internal Medicine and Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
- Endocrinology Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Federica Nista
- Endocrinology Unit, Department of Internal Medicine and Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
- Endocrinology Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Marica Arvigo
- Endocrinology Unit, Department of Internal Medicine and Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
| | - Jessica Amarù
- Endocrinology Unit, Department of Internal Medicine and Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
| | - Diego Criminelli Rossi
- Division of Neurosurgery, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Gianluigi Zona
- Division of Neurosurgery, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Diego Ferone
- Endocrinology Unit, Department of Internal Medicine and Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
- Endocrinology Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Federico Gatto
- Endocrinology Unit, Department of Internal Medicine and Center of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
- Endocrinology Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
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Ucan B, Kizilgul M, Karci AC, Duger H, Erkam Sencar M, Imga NN, Demirci T, Berker D, Erman Cakal. THE PREVALENCE OF CANCER AND ITS RELATION TO DISEASE ACTIVITY IN PATIENTS WITH ACROMEGALY: TWO CENTERS' EXPERIENCE. Endocr Pract 2021; 27:51-55. [PMID: 33475501 DOI: 10.4158/ep-2020-0398] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE Acromegaly is characterized by increased serum concentrations of growth hormone (GH) and insulin-like growth factor 1 (IGF-1). Although animal studies have demonstrated a relationship between these hormones and cancer risk, the results of human studies evaluating cancer prevalence in acromegaly are inconsistent. We aimed to investigate the prevalence of malignant neoplasms in patients with acromegaly. METHODS Cancer risk was evaluated in a cohort of 280 patients (male/female: 120/160; mean age: 50.93 ± 12.07 years) with acromegaly. Patients were categorized into 2 groups according to the presence or absence of cancer. Standard incidence ratios were calculated as compared to the general population. RESULTS From 280 patients, cancer was diagnosed in 19 (6.8%) patients; 9 (47%) of them had thyroid cancer, which was the most common cancer type. Standard incidence ratios of all cancers were 0.8 (95% CI, 0.5-1.1) and 1.0 (95% CI, 0.8-1.3) in men and women, respectively. Compared to patients without cancer, the current age was higher in patients with cancer (59 [49-65] to 51 [42-59], P = .027). In contrast, the age at diagnosis was similar in both groups. Not only was the time to diagnosis and disease duration similar in both groups but also the basal and current GH and IGF-1 levels. The prevalence of active disease was also similar between the groups (32% to 23%, P = .394). CONCLUSION Our findings were not consistent with the studies suggesting that patients with acromegaly encounter an increased cancer risk. Furthermore, there were similar basal and current GH and IGF-1 levels in patients with acromegaly, both with and without cancer.
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Affiliation(s)
- Bekir Ucan
- Department of Endocrinology and Metabolism, University of Health Sciences, Dıskapı Yıldırım Beyazıt Training and Research Hospital, Ankara, Turkey
| | - Muhammed Kizilgul
- Department of Endocrinology and Metabolism, University of Health Sciences, Dıskapı Yıldırım Beyazıt Training and Research Hospital, Ankara, Turkey.
| | - Alper Cagri Karci
- Department of Endocrinology and Metabolism, University of Health Sciences, Numune Training and Research Hospital, Ankara, Turkey
| | - Hakan Duger
- Department of Endocrinology and Metabolism, University of Health Sciences, Dıskapı Yıldırım Beyazıt Training and Research Hospital, Ankara, Turkey
| | - Muhammed Erkam Sencar
- Department of Endocrinology and Metabolism, University of Health Sciences, Dıskapı Yıldırım Beyazıt Training and Research Hospital, Ankara, Turkey
| | - Narin Nasiroglu Imga
- Department of Endocrinology and Metabolism, University of Health Sciences, Numune Training and Research Hospital, Ankara, Turkey
| | - Taner Demirci
- Department of Endocrinology and Metabolism, University of Health Sciences, Dıskapı Yıldırım Beyazıt Training and Research Hospital, Ankara, Turkey
| | - Dilek Berker
- Department of Endocrinology and Metabolism, University of Health Sciences, Numune Training and Research Hospital, Ankara, Turkey
| | - Erman Cakal
- Department of Endocrinology and Metabolism, University of Health Sciences, Dıskapı Yıldırım Beyazıt Training and Research Hospital, Ankara, Turkey
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15
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A high-throughput assay for the quantification of intact Insulin-like Growth Factor I in human serum using online SPE-LC-HRMS. Clin Chim Acta 2020; 510:391-399. [DOI: 10.1016/j.cca.2020.07.054] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/27/2020] [Accepted: 07/27/2020] [Indexed: 02/04/2023]
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16
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Bonert V, Mirocha J, Carmichael J, Yuen KCJ, Araki T, Melmed S. Cost-Effectiveness and Efficacy of a Novel Combination Regimen in Acromegaly: A Prospective, Randomized Trial. J Clin Endocrinol Metab 2020; 105:5869881. [PMID: 32754748 DOI: 10.1210/clinem/dgaa444] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/07/2020] [Indexed: 12/17/2022]
Abstract
CONTEXT Combination therapy with somatostatin receptor ligand (SRL) plus pegvisomant for patients with acromegaly is recommended after a maximizing dose on monotherapy. Lower-dose combination regimens are not well studied. OBJECTIVE To compare cost-effectiveness and efficacy of 3 lower-dose combination regimens in controlled and uncontrolled acromegaly. DESIGN AND SETTING Prospective, randomized, open-label, parallel arm study at a tertiary referral pituitary center. PATIENTS Adults with acromegaly regardless of response to prior SRL and biochemical control status at baseline, stratified by an SRL dose required for insulin-like growth factor (IGF)-I normalization during any 3-month period within 12 months preceding enrollment. INTERVENTION Combination therapy for 24 to 32 weeks on arm A, high-dose SRL (lanreotide 120 mg/octreotide long-acting release [LAR] 30 mg) plus weekly pegvisomant (40-160 mg/week); arm B, low-dose SRL (lanreotide 60 mg/octreotide LAR 10 mg) plus weekly pegvisomant; or arm C, low-dose SRL plus daily pegvisomant (15-60 mg/day). MAIN OUTCOME MEASURE Monthly treatment cost in each arm in participants completing ≥ 24 weeks of therapy. RESULTS Sixty patients were enrolled and 52 were evaluable. Fifty of 52 (96%) demonstrated IGF-I control regardless of prior SRL responsiveness (arm A, 14/15 [93.3%]; arm B, 22/23 [95.7%]; arm C, 14/14 [100%]). Arm B was least costly (mean, $9837 ± 1375 per month), arm C was most expensive (mean, $22543 ± 11158 per month), and arm A had an intermediate cost (mean, $14261 ± 1645 per month). Approximately 30% of patients required pegvisomant dose uptitration. Rates of adverse events were all < 10%. CONCLUSIONS Low-dose SRL plus weekly pegvisomant represents a novel dosing option for achieving cost-effective, optimal biochemical control in patients with uncontrolled acromegaly requiring combination therapy.
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MESH Headings
- Acromegaly/drug therapy
- Acromegaly/economics
- Adult
- Cost-Benefit Analysis
- Delayed-Action Preparations
- Dosage Forms
- Dose-Response Relationship, Drug
- Drug Administration Schedule
- Drug Costs
- Drug Therapy, Combination/adverse effects
- Drug Therapy, Combination/economics
- Female
- Human Growth Hormone/administration & dosage
- Human Growth Hormone/adverse effects
- Human Growth Hormone/analogs & derivatives
- Human Growth Hormone/economics
- Humans
- Male
- Middle Aged
- Octreotide/administration & dosage
- Octreotide/adverse effects
- Octreotide/economics
- Peptides, Cyclic/administration & dosage
- Peptides, Cyclic/adverse effects
- Peptides, Cyclic/economics
- Receptors, Somatostatin/agonists
- Somatostatin/administration & dosage
- Somatostatin/adverse effects
- Somatostatin/analogs & derivatives
- Somatostatin/economics
- Therapies, Investigational/adverse effects
- Therapies, Investigational/economics
- Therapies, Investigational/methods
- Treatment Outcome
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Affiliation(s)
- Vivien Bonert
- Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California
| | - James Mirocha
- Biostatistics and Bioinformatics Research Center, Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - John Carmichael
- Division of Endocrinology and Metabolism, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Kevin C J Yuen
- Department of Neuroendocrinology and Neurosurgery, Barrow Neurological Institute, University of Arizona College of Medicine and Creighton School of Medicine, Phoenix, Arizona
| | - Takako Araki
- Division of Diabetes, Endocrinology and Metabolism, University of Minnesota, Minneapolis, Minnesota
| | - Shlomo Melmed
- Pituitary Center, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California
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17
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Use of capillary dried blood for quantification of intact IGF-I by LC–HRMS for antidoping analysis. Bioanalysis 2020; 12:737-752. [DOI: 10.4155/bio-2020-0013] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Background: IGF-I is used as a biomarker to detect Growth Hormone doping in athletes’ blood samples. Objective: Our aim was to develop and validate a fast, high-throughput and accurate quantification of intact IGF-I from volumetric absorptive microsampling (VAMS) dried blood using LC coupled to high resolution mass spectrometry (LC–HRMS). Methodology & results: IGF-I was extracted from the VAMS, released from its binding proteins, concentrated using microelution SPE and analyzed by LC–HRMS. The method was successfully validated in accordance with the World Anti-Doping Agency's requirements. Subsequently, IGF-I measurements from capillary dried blood and serum were compared. Conclusion: The combination of VAMS, microelution SPE and LC–HRMS is a promising strategy applicable to IGF-I quantification in athletes’ samples.
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Klont F, Kieneker LM, Gomes-Neto AW, Stam SP, ten Hacken NHT, Kema IP, van Beek AP, van den Berg E, Horvatovich P, Bischoff R, Bakker SJL. Female Specific Association of Low Insulin-Like Growth Factor 1 (IGF1) Levels with Increased Risk of Premature Mortality in Renal Transplant Recipients. J Clin Med 2020; 9:jcm9020293. [PMID: 31973007 PMCID: PMC7073643 DOI: 10.3390/jcm9020293] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/14/2020] [Accepted: 01/17/2020] [Indexed: 01/08/2023] Open
Abstract
Associations between insulin-like growth factor 1 (IGF1) and mortality have been reported to be female specific in mice and in human nonagenarians. Intervention in the growth hormone (GH)-IGF1 axis may particularly benefit patients with high risk of losing muscle mass, including renal transplant recipients (RTR). We investigated whether a potential association of circulating IGF1 with all-cause mortality in stable RTR could be female specific and mediated by variation in muscle mass. To this end, plasma IGF1 levels were measured in 277 female and 343 male RTR by mass spectrometry, and their association with mortality was assessed by Cox regression. During a median follow-up time of 5.4 years, 56 female and 77 male RTR died. In females, IGF1 was inversely associated with risk (hazard ratio (HR) per 1-unit increment in log2-transformed (doubling of) IGF1 levels, 95% confidence interval (CI)) of mortality (0.40, 0.24-0.65; p < 0.001), independent of age and the estimated Glomerular filtration rate (eGFR). In equivalent analyses, no significant association was observed for males (0.85, 0.56-1.29; p = 0.44), for which it should be noted that in males, age was negatively and strongly associated with IGF1 levels. The association for females remained materially unchanged upon adjustment for potential confounders and was furthermore found to be mediated for 39% by 24 h urinary creatinine excretion. In conclusion, low IGF1 levels associate with an increased risk of all-cause mortality in female RTR, which may link to conditions of low muscle mass that are known to be associated with poor outcomes in transplantation patients. For males, the strongly negative association of age with IGF1 levels may explain why low IGF1 levels were not found to be associated with an increased risk of all-cause mortality.
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Affiliation(s)
- Frank Klont
- Department of Analytical Biochemistry, Groningen Research Institute of Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands; (P.H.); (R.B.)
- Correspondence:
| | - Lyanne M. Kieneker
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands; (L.M.K.); (A.W.G.-N.); (S.P.S.); (E.v.d.B.); (S.J.L.B.)
| | - Antonio W. Gomes-Neto
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands; (L.M.K.); (A.W.G.-N.); (S.P.S.); (E.v.d.B.); (S.J.L.B.)
| | - Suzanne P. Stam
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands; (L.M.K.); (A.W.G.-N.); (S.P.S.); (E.v.d.B.); (S.J.L.B.)
| | - Nick H. T. ten Hacken
- Department of Pulmonary Diseases, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands;
| | - Ido P. Kema
- Department of Laboratory Medicine, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands;
| | - André P. van Beek
- Department of Endocrinology, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands;
| | - Else van den Berg
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands; (L.M.K.); (A.W.G.-N.); (S.P.S.); (E.v.d.B.); (S.J.L.B.)
| | - Péter Horvatovich
- Department of Analytical Biochemistry, Groningen Research Institute of Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands; (P.H.); (R.B.)
| | - Rainer Bischoff
- Department of Analytical Biochemistry, Groningen Research Institute of Pharmacy, University of Groningen, 9713 AV Groningen, The Netherlands; (P.H.); (R.B.)
| | - Stephan J. L. Bakker
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands; (L.M.K.); (A.W.G.-N.); (S.P.S.); (E.v.d.B.); (S.J.L.B.)
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19
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Granada ML. Biochemical following-up of treated acromegaly. Limitations of the current determinations of IGF-I and perspective. MINERVA ENDOCRINOL 2019; 44:143-158. [DOI: 10.23736/s0391-1977.18.02922-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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