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Bielohuby M, Bidlingmaier M, Schwahn U. Control of (pre)-analytical aspects in immunoassay measurements of metabolic hormones in rodents. Endocr Connect 2018; 7. [PMID: 29540488 PMCID: PMC5881432 DOI: 10.1530/ec-18-0035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The measurement of circulating hormones by immunoassay remains a cornerstone in preclinical endocrine research. For scientists conducting and interpreting immunoassay measurements of rodent samples, the paramount aim usually is to obtain reliable and meaningful measurement data in order to draw conclusions on biological processes. However, the biological variability between samples is not the only variable affecting the readout of an immunoassay measurement and a considerable amount of unwanted or unintended variability can be quickly introduced during the pre-analytical and analytical phase. This review aims to increase the awareness for the factors 'pre-analytical' and 'analytical' variability particularly in the context of immunoassay measurement of circulating metabolic hormones in rodent samples. In addition, guidance is provided how to gain control over these variables and how to avoid common pitfalls associated with sample collection, processing, storage and measurement. Furthermore, recommendations are given on how to perform a basic validation of novel single and multiplex immunoassays for the measurement of metabolic hormones in rodents. Finally, practical examples from immunoassay measurements of plasma insulin in mice address the factors 'sampling site and inhalation anesthesia' as frequent sources of introducing an unwanted variability during the pre-analytical phase. The knowledge about the influence of both types of variability on the immunoassay measurement of circulating hormones as well as strategies to control these variables are crucial, on the one hand, for planning and realization of metabolic rodent studies and, on the other hand, for the generation and interpretation of meaningful immunoassay data from rodent samples.
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Affiliation(s)
| | - Martin Bidlingmaier
- Endocrine Research LaboratoriesMedizinische Klinik und Poliklinik IV, Klinikum der Universität München, Munich, Germany
| | - Uwe Schwahn
- Sanofi-Aventis Deutschland GmbHR&D, Industriepark Höchst, Frankfurt, Germany
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Stock P, Bielohuby M, Staege MS, Hsu MJ, Bidlingmaier M, Christ B. Impairment of Host Liver Repopulation by Transplanted Hepatocytes in Aged Rats and the Release by Short-Term Growth Hormone Treatment. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:553-569. [PMID: 28088007 DOI: 10.1016/j.ajpath.2016.11.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 10/21/2016] [Accepted: 11/28/2016] [Indexed: 12/28/2022]
Abstract
Hepatocyte transplantation is an alternative to whole liver transplantation. Yet, efficient liver repopulation by transplanted hepatocytes is low in livers of old animals. This restraint might be because of the poor proliferative capacity of aged donor hepatocytes or the regenerative impairment of the recipient livers. The age-dependent liver repopulation by transplanted wild-type hepatocytes was investigated in juvenile and senescent rats deficient in dipeptidyl-peptidase IV. Repopulation was quantified by flow cytometry and histochemical estimation of dipeptidyl-peptidase IV enzyme activity of donor cells in the negative host liver. As a potential pathway involved, expression of cell cycle proteins was assessed. Irrespective of the age of the donor hepatocytes, large cell clusters appeared in juvenile, but only small clusters in senescent host livers. Because juvenile and senescent donor hepatocytes were likewise functional, host-derived factor(s) impaired senescent host liver repopulation. Growth hormone levels were significantly higher in juvenile than in senescent rats, suggesting that growth hormone might promote host liver repopulation. Indeed, short-term treatment with growth hormone augmented senescent host liver repopulation involving the growth hormone-mediated release of the transcriptional blockade of genes associated with cell cycle progression. Short-term growth hormone substitution might improve liver repopulation by transplanted hepatocytes, thus augmenting the therapeutic benefit of clinical hepatocyte transplantation in older patients.
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Affiliation(s)
- Peggy Stock
- Division of Applied Molecular Hepatology, Clinics and Policlinics of Visceral, Transplantation, Thoracic, and Vascular Surgery, University of Leipzig, Leipzig, Germany.
| | - Maximilian Bielohuby
- Endocrine Research Unit, Department of Internal Medicine IV, Ludwig Maximilian University, Munich, Germany
| | - Martin S Staege
- Department of Pediatrics I, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Mei-Ju Hsu
- Division of Applied Molecular Hepatology, Clinics and Policlinics of Visceral, Transplantation, Thoracic, and Vascular Surgery, University of Leipzig, Leipzig, Germany
| | - Martin Bidlingmaier
- Endocrine Research Unit, Department of Internal Medicine IV, Ludwig Maximilian University, Munich, Germany
| | - Bruno Christ
- Division of Applied Molecular Hepatology, Clinics and Policlinics of Visceral, Transplantation, Thoracic, and Vascular Surgery, University of Leipzig, Leipzig, Germany
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Bielohuby M, Zarkesh-Esfahani SH, Manolopoulou J, Wirthgen E, Walpurgis K, Toghiany Khorasgani M, Aghili ZS, Wilkinson IR, Hoeflich A, Thevis M, Ross RJ, Bidlingmaier M. Validation of serum IGF-I as a biomarker to monitor the bioactivity of exogenous growth hormone agonists and antagonists in rabbits. Dis Model Mech 2014; 7:1263-73. [PMID: 25239917 PMCID: PMC4213730 DOI: 10.1242/dmm.016519] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The development of new growth hormone (GH) agonists and growth hormone antagonists (GHAs) requires animal models for pre-clinical testing. Ideally, the effects of treatment are monitored using the same pharmacodynamic marker that is later used in clinical practice. However, intact rodents are of limited value for this purpose because serum IGF-I, the most sensitive pharmacodynamic marker for the action of GH in humans, shows no response to treatment with recombinant human GH and there is little evidence for the effects of GHAs, except when administered at very high doses or when overexpressed. As an alternative, more suitable model, we explored pharmacodynamic markers of GH action in intact rabbits. We performed the first validation of an IGF-I assay for the analysis of rabbit serum and tested precision, sensitivity, linearity and recovery using an automated human IGF-I assay (IDS-iSYS). Furthermore, IGF-I was measured in rabbits of different strains, age groups and sexes, and we monitored IGF-I response to treatment with recombinant human GH or the GHA Pegvisomant. For a subset of samples, we used LC-MS/MS to measure IGF-I, and quantitative western ligand blot to analyze IGF-binding proteins (IGFBPs). Although recovery of recombinant rabbit IGF-I was only 50% in the human IGF-I assay, our results show that the sensitivity, precision (1.7–3.3% coefficient of variation) and linearity (90.4–105.6%) were excellent in rabbit samples. As expected, sex, age and genetic background were major determinants of IGF-I concentration in rabbits. IGF-I and IGFBP-2 levels increased after single and multiple injections of recombinant human GH (IGF-I: 286±22 versus 434±26 ng/ml; P<0.01) and were highly correlated (P<0.0001). Treatment with the GHA lowered IGF-I levels from the fourth injection onwards (P<0.01). In summary, we demonstrated that the IDS-iSYS IGF-I immunoassay can be used in rabbits. Similar to rodents, rabbits display variations in IGF-I depending on sex, age and genetic background. Unlike in rodents, the IGF-I response to treatment with recombinant human GH or a GHA closely mimics the pharmacodynamics seen in humans, suggesting that rabbits are a suitable new model to test human GH agonists and antagonists.
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Affiliation(s)
- Maximilian Bielohuby
- Endocrine Research Unit, Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians University, 80336 Munich, Germany
| | - Sayyed Hamid Zarkesh-Esfahani
- Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan 81746-73695, Iran. Department of Immunology, Medical School, Isfahan University of Medical Sciences, Isfahan 81746-73461, Iran. The Department of Human Metabolism, The University of Sheffield, Sheffield S10 2JF, UK
| | | | - Elisa Wirthgen
- Ligandis GbR, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany
| | - Katja Walpurgis
- German Sport University Cologne, Institute of Biochemisty/Center for Preventive Doping Research, 50933 Cologne, Germany
| | | | - Zahra Sadat Aghili
- Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan 81746-73695, Iran
| | - Ian Robert Wilkinson
- The Department of Human Metabolism, The University of Sheffield, Sheffield S10 2JF, UK
| | - Andreas Hoeflich
- Leibniz Institute for Farm Animal Biology (FBN), Institute of Genome Biology, 18196 Dummerstorf, Germany
| | - Mario Thevis
- German Sport University Cologne, Institute of Biochemisty/Center for Preventive Doping Research, 50933 Cologne, Germany
| | - Richard J Ross
- The Department of Human Metabolism, The University of Sheffield, Sheffield S10 2JF, UK
| | - Martin Bidlingmaier
- Endocrine Research Unit, Medizinische Klinik und Poliklinik IV, Ludwig-Maximilians University, 80336 Munich, Germany.
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