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Gerred K, Kapoor A. A fit-for-purpose validation of a commercial radioimmunoassay for measurement of human peripheral oxytocin. Biochem Biophys Rep 2024; 38:101666. [PMID: 38434143 PMCID: PMC10907144 DOI: 10.1016/j.bbrep.2024.101666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/07/2023] [Accepted: 02/12/2024] [Indexed: 03/05/2024] Open
Abstract
Oxytocin (OT) is a peptide hormone synthesized in the hypothalamus and released into systemic circulation or other areas of the brain. Its physiological roles include action as a hormone with stimulation of uterine contractions and that as a neuromodulator with involvement in social behaviors and regulation of mood. Its small size and low levels within biological matrices make it challenging to accurately measure. The goal of this study was to demonstrate the specificity of the antibody, sensitivity, and reproducibility of the Phoenix Pharmaceuticals (PP) OT radioimmunoassay (RIA) for use in human urine, serum, and saliva. Specificity of the antibody was assessed by high pressure liquid chromatography with ultraviolet (HPLC-UV) separation and assay of the fractions. Immunoreactivity was evaluated using the percent OT bound, and the fraction retention times were compared to the retention time of an intact OT standard to determine which fractions contained OT in the extracted samples. Reproducibility was assessed by running replicates of pools of each biomatrix over several assays. Sensitivity was assessed by repeated measurement of physiologically relevant low-concentration specimens. In all tested specimens the greatest reactivity in assay corresponded to the same fraction(s) as the OT standard. Only minimal reactivity was found in the other fractions, suggesting that in an unfractionated sample the antibody reacts mostly with intact OT. Reproducibility was acceptable for all specimens and the coefficient of variation (CV) ranged from 3.72 to 8.04% and 5.89-12.8%, for intra and inter-assay, respectively. The limits of quantitation (LOQ) were sufficient for measurement of normal values in urine (0.643 & 1.43 pg/mL), serum (1.90 pg/mL), and saliva pools (0.485 & 4.42 pg/mL). In conclusion, the PP OT RIA is specific and sensitive enough for reproducible measurement of intact OT in human peripheral biological matrices.
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Affiliation(s)
- Keenan Gerred
- Wisconsin National Primate Research Center, University of Wisconsin-Madison, 1220 Capitol Court, Madison, WI, 53715, USA
| | - Amita Kapoor
- Wisconsin National Primate Research Center, University of Wisconsin-Madison, 1220 Capitol Court, Madison, WI, 53715, USA
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2
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Bijttebier S, Nguyen TH, McIntosh MP, Kirkpatrick C, Remmerie B, Dillen L, Lambert P. Application of immunocapture and nanoflow LC-MS/MS to overcome the barriers to the quantitation of oxytocin in plasma of women in third stage labour. Br J Clin Pharmacol 2024. [PMID: 38890002 DOI: 10.1111/bcp.16135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 02/19/2024] [Accepted: 02/23/2024] [Indexed: 06/20/2024] Open
Abstract
AIMS Postpartum haemorrhage (PPH) is the leading cause of maternal mortality worldwide. To prevent PPH, the WHO recommends administration of oxytocin (OT) immediately after birth, i.e. during the third stage of labour (TSL). Previous studies demonstrate that methods to quantify OT in biological matrices, e.g. enzyme-linked immunosorbent assays (ELISA), radioimmunoassays (RIA) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) lack the specificity and/or sensitivity to accurately quantify OT in plasma from women administered OT during TSL. This is due to increased metabolic clearance of OT in late-stage pregnancy and at the time of childbirth, resulting in extremely low OT plasma concentrations. This study describes the development of an ultra-sensitive bioanalytical method that overcomes the issues previously reported and enables accurate pharmacokinetic analyses of exogenously administered OT in TSL. METHODS A selective and sensitive assay to quantify OT in TSL plasma was developed. Immunoprecipitation (IP) was applied to selectively extract OT from the TSL plasma, thereby generating clean extracts compatible with nanoflow LC (nLC). nLC-MS/MS was chosen for its high sensitivity and ability to differentiate between OT and potentially co-captured OT-like immunoreactive products. RESULTS The presented methodology is accurate and precise, with a good linear fit between 100-10 000 fg mL-1 OT. TSL plasma samples from a clinical phase 1 study (NCT02999100) were analysed successfully, enabling OT quantification down to 100 fg mL-1. CONCLUSIONS The presented IP-nLC-MS/MS method succeeded in overcoming the sensitivity challenge related to the assay of OT in TSL plasma and thereby revealing the PK profiles of OT in TSL plasma clinical study samples.
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Affiliation(s)
- Sebastiaan Bijttebier
- Janssen Pharmaceutica, Bioanalytical Discovery & Development Sciences, Beerse, Belgium
| | - Tri-Hung Nguyen
- Drug Delivery Disposition and Dynamics, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia
| | - Michelle P McIntosh
- Drug Delivery Disposition and Dynamics, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia
| | - Carl Kirkpatrick
- Drug Delivery Disposition and Dynamics, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia
| | - Bart Remmerie
- Janssen Pharmaceutica, Clinical Pharmacology, Beerse, Belgium
| | - Lieve Dillen
- Janssen Pharmaceutica, Bioanalytical Discovery & Development Sciences, Beerse, Belgium
| | - Pete Lambert
- Drug Delivery Disposition and Dynamics, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia
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3
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Wen X, Zhang X, Qiu Y, Wang Y, Zhu L, Liu T, Ruan Z. The Minhang Pediatric Biobank cohort study: protocol overview and baseline characteristics. BMC Pediatr 2024; 24:282. [PMID: 38678186 PMCID: PMC11055290 DOI: 10.1186/s12887-024-04763-6] [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: 10/09/2023] [Accepted: 04/15/2024] [Indexed: 04/29/2024] Open
Abstract
BACKGROUND Little has been done to establish biobanks for studying the environment and lifestyle risk factors for diseases among the school-age children. The Minhang Pediatric Biobank (MPB) cohort study aims to identify factors associated with health and diseases of school-aged children living in the urban or suburban area of Shanghai. METHODS This population-based cohort study was started in all sub-districts/towns of Minhang district of Shanghai in 2014. First-grade students in elementary school were enrolled during the time of their routine physical examinations, with self-administered questionnaires completed by their primary caregivers. Additional information was extracted from multiple health information systems. Urine and saliva samples were collected during the baseline survey and follow-up visits. RESULTS At the end of 2014 academic year, a total number of 8412 children and their parents were recruited, including 4339 boys and 4073 girls. All the participants completed the baseline survey and physical examination, and 7128 urine and 2767 saliva samples were collected. The five most prevalent childhood diseases in this population were dental caries, bronchitis, pneumonia, asthma and overweight/obese. CONCLUSIONS The MPB cohort has been successfully established, serving as a useful platform for future research relating to the genetic, environmental and lifestyle risk factors for childhood diseases.
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Affiliation(s)
- Xiaosa Wen
- Minhang District Center for Disease Control and Prevention, Shanghai, China
| | - Xinyue Zhang
- Key Laboratory of Environmental Medicine and Engineering of Ministry of Education, and Department of Epidemiology & Health Statistics, School of Public Health, Southeast University, 87 Dingjiaqiao, Gulou District, Jiangsu, Nanjing, 210096, China
| | - Yun Qiu
- Department of Public Health, School of Medicine, Nanjing University of Chinese Medicine, Nanjing, China
| | - Yaqin Wang
- School of Health and Life Sciences, University of Health and Rehabilitation Sciences, Qingdao, China
| | - Liujie Zhu
- Key Laboratory of Environmental Medicine and Engineering of Ministry of Education, and Department of Epidemiology & Health Statistics, School of Public Health, Southeast University, 87 Dingjiaqiao, Gulou District, Jiangsu, Nanjing, 210096, China
| | - Tao Liu
- Department of Biochemistry and Molecular Biology, School of Medicine, Southeast University, Jiangsu, Nanjing, 210096, China.
- Jiangsu Provincial Key Laboratory of Critical Care Medicine and Department of Critical Care Medicine, School of Medicine, Zhongda Hospital, Southeast University, Nanjing, China.
| | - Zengliang Ruan
- Key Laboratory of Environmental Medicine and Engineering of Ministry of Education, and Department of Epidemiology & Health Statistics, School of Public Health, Southeast University, 87 Dingjiaqiao, Gulou District, Jiangsu, Nanjing, 210096, China.
- Department of Epidemiology, School of Public Health, Sun Yat-Sen University, Guangzhou, China.
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
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4
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López-Arjona M, Cerón JJ, Mateo SV, Contreras-Aguilar MD, Martínez-Subiela S. Validation of two immunoassays for oxytocin measurements in human saliva. PLoS One 2024; 19:e0297539. [PMID: 38635553 PMCID: PMC11025789 DOI: 10.1371/journal.pone.0297539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 01/09/2024] [Indexed: 04/20/2024] Open
Abstract
The objective of this research was to develop and validate two immunoassays for oxytocin measurement in human saliva, one using a monoclonal and the other a polyclonal antibody against oxytocin, whose affinity for oxytocin was tested by an antibody mapping epitope analysis. These assays were analytically validated and used to compare oxytocin concentrations with those obtained with a commercial kit before and after the extraction or reduction/alkylation (R/A) treatments to saliva samples. The assays were also used to evaluate changes in salivary oxytocin concentrations following a physical effort and an induced psychological stress, which have previously been described as situations that cause an increase in salivary oxytocin. Both assays showed to be precise and accurate in the validation studies, and the antibodies used showed a defined binding region in case of the monoclonal antibody, whereas the polyclonal antibody showed binding events through all the oxytocin sequence. Although the monoclonal and polyclonal assays showed a positive correlation, they give results in a different range of magnitude. Both assays showed significant increases in oxytocin concentrations when applied after the physical effort and the psychological stress. This study shows that a variability in the reported values of oxytocin can occur depending on the assay and indicates that the use of different types of antibodies can give a different range of values when measuring oxytocin in saliva.
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Affiliation(s)
- Marina López-Arjona
- Department of Animal and Food Science, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - José Joaquín Cerón
- Interdisciplinary Laboratory of Clinical Analysis of the University of Murcia (Interlab-UMU), Regional Campus of International Excellence ‘Campus Mare Nostrum’, University of Murcia, Murcia, Spain
| | - Sandra V. Mateo
- Molecular Inflammation Group, University Clinical Hospital Virgen de la Arrixaca, Biomedical Research Institute of Murcia (IMIB-Pascual Parrilla), Murcia, Spain
| | - María Dolores Contreras-Aguilar
- Interdisciplinary Laboratory of Clinical Analysis of the University of Murcia (Interlab-UMU), Regional Campus of International Excellence ‘Campus Mare Nostrum’, University of Murcia, Murcia, Spain
| | - Silvia Martínez-Subiela
- Interdisciplinary Laboratory of Clinical Analysis of the University of Murcia (Interlab-UMU), Regional Campus of International Excellence ‘Campus Mare Nostrum’, University of Murcia, Murcia, Spain
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5
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Ramö Isgren A, Carlhäll S, Dennis Retrato M, Kodikara C, A. Ubhayasekera K, Kjölhede P, Bergquist J, Blomberg M. The association between maternal body mass index and serial plasma oxytocin levels during labor. PLoS One 2023; 18:e0290038. [PMID: 37566578 PMCID: PMC10420366 DOI: 10.1371/journal.pone.0290038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 08/01/2023] [Indexed: 08/13/2023] Open
Abstract
OBJECTIVE To evaluate the association between maternal body mass index (BMI) and plasma oxytocin (OT) levels at different OT infusion rates in labor. METHODS A prospective observational study analyzing serial plasma samples in laboring women with OT infusion. The women were categorized into three groups, women with non-obesity (BMI 18.5-29.9, n = 12), obesity (BMI 30.0-34.9, n = 13), and morbid obesity (BMI ≥ 35.0, n = 15). Plasma OT was analyzed using tandem mass spectrometry. RESULTS Except for a low positive correlation between OT levels and BMI and significantly increased plasma OT levels in women with morbid obesity at the OT infusion rate of 3.3 mU/min, no significant differences in OT levels between the BMI groups were found. Further, the inter-individual differences in OT levels were large and no dose-dependent increase of OT levels was seen. CONCLUSIONS Other factors than plasma OT levels may be more likely to determine the clinical response of OT infusion in women with obesity. Perhaps the observed clinical need and individual response would be a better predictor of plasma OT levels than a pre-determined OT infusion rate. The OT dosage guidelines for labor augmentation should be individualized according to clinical response rather than generalized. TRIAL REGISTRATION Clinical trial registration: ClinicalTrials.gov ID NCT04093479.
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Affiliation(s)
- Anna Ramö Isgren
- Department of Obstetrics and Gynecology and Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Sara Carlhäll
- Department of Obstetrics and Gynecology and Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Mark Dennis Retrato
- Department of Chemistry-BMC, Analytical Chemistry and Neurochemistry, Uppsala University, Uppsala, Sweden
| | - Chamali Kodikara
- Department of Chemistry-BMC, Analytical Chemistry and Neurochemistry, Uppsala University, Uppsala, Sweden
| | - Kumari A. Ubhayasekera
- Department of Chemistry-BMC, Analytical Chemistry and Neurochemistry, Uppsala University, Uppsala, Sweden
| | - Preben Kjölhede
- Department of Obstetrics and Gynecology and Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Jonas Bergquist
- Department of Chemistry-BMC, Analytical Chemistry and Neurochemistry, Uppsala University, Uppsala, Sweden
| | - Marie Blomberg
- Department of Obstetrics and Gynecology and Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
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6
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Gan HW, Leeson C, Aitkenhead H, Dattani M. Inaccuracies in plasma oxytocin extraction and enzyme immunoassay techniques. COMPREHENSIVE PSYCHONEUROENDOCRINOLOGY 2023; 15:100188. [PMID: 37360277 PMCID: PMC10285453 DOI: 10.1016/j.cpnec.2023.100188] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 06/01/2023] [Accepted: 06/04/2023] [Indexed: 06/28/2023] Open
Abstract
Numerous studies have reported extensive associations between plasma oxytocin (OXT) concentrations and various human physiological and neurobehavioral processes. Measurement of OXT is fraught with difficulty due to its low molecular weight and plasma concentrations, with no consensus as to the optimal conditions for pre-analytical sample extraction, standards for immunoassay validation or the ideal protease inhibitors to prevent OXT degradation. Previous attempts at determining the efficacy of various purification techniques such as solid phase extraction (SPE) or ultrafiltration have only utilized human plasma samples, making it difficult to dissect out whether the effect of interference comes from the extraction process itself or cross-reactivity with other proteins. By testing these on pure OXT solutions, we demonstrate poor recovery efficacy and reliability of reversed phase SPE (maximum 58.1%) and ultrafiltration (<1%) techniques, and the potential for the former to introduce interference into enzyme immunoassay (EIA) measurements. The clonality of antibodies used in EIA kits also potentially contributes to the differences in the readings obtained, and we validate an EIA kit which did not require pre-analytical sample extraction with low cross-reactivity and high reliability (intraclass correlation coefficient 0.980 (95% CI 0.896-0.999). Biochemical techniques used for measuring plasma OXT concentrations must therefore be internally validated prior to translation into clinical studies.
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Affiliation(s)
- Hoong-Wei Gan
- Genetics & Genomic Medicine Research and Training Department, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, United Kingdom
- Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, United Kingdom
| | - Clare Leeson
- Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, United Kingdom
| | - Helen Aitkenhead
- Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, United Kingdom
| | - Mehul Dattani
- Genetics & Genomic Medicine Research and Training Department, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, United Kingdom
- Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, United Kingdom
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7
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Bienboire-Frosini C, Marcet-Rius M, Orihuela A, Domínguez-Oliva A, Mora-Medina P, Olmos-Hernández A, Casas-Alvarado A, Mota-Rojas D. Mother-Young Bonding: Neurobiological Aspects and Maternal Biochemical Signaling in Altricial Domesticated Mammals. Animals (Basel) 2023; 13:ani13030532. [PMID: 36766424 PMCID: PMC9913798 DOI: 10.3390/ani13030532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/27/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
Mother-young bonding is a type of early learning where the female and their newborn recognize each other through a series of neurobiological mechanisms and neurotransmitters that establish a behavioral preference for filial individuals. This process is essential to promote their welfare by providing maternal care, particularly in altricial species, animals that require extended parental care due to their limited neurodevelopment at birth. Olfactory, auditory, tactile, and visual stimuli trigger the neural integration of multimodal sensory and conditioned affective associations in mammals. This review aims to discuss the neurobiological aspects of bonding processes in altricial mammals, with a focus on the brain structures and neurotransmitters involved and how these influence the signaling during the first days of the life of newborns.
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Affiliation(s)
- Cécile Bienboire-Frosini
- Department of Molecular Biology and Chemical Communication, Research Institute in Semiochemistry and Applied Ethology (IRSEA), 84400 Apt, France
| | - Míriam Marcet-Rius
- Animal Behaviour and Welfare Department, Research Institute in Semiochemistry and Applied Ethology (IRSEA), 84400 Apt, France
| | - Agustín Orihuela
- Facultad de Ciencias Agropecuarias, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Mexico
| | - Adriana Domínguez-Oliva
- Neurophysiology, Behavior and Animal Welfare Assessment, DPAA, Universidad Autónoma Metropolitana, Xochimilco Campus, Mexico City 04960, Mexico
| | - Patricia Mora-Medina
- Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de Mexico (UNAM), Cuautitlán Izcalli 54740, Mexico
| | - Adriana Olmos-Hernández
- Division of Biotechnology—Bioterio and Experimental Surgery, Instituto Nacional de Rehabilitación-Luis Guillermo Ibarra Ibarra (INR-LGII), Tlalpan, Mexico City 14389, Mexico
| | - Alejandro Casas-Alvarado
- Neurophysiology, Behavior and Animal Welfare Assessment, DPAA, Universidad Autónoma Metropolitana, Xochimilco Campus, Mexico City 04960, Mexico
| | - Daniel Mota-Rojas
- Neurophysiology, Behavior and Animal Welfare Assessment, DPAA, Universidad Autónoma Metropolitana, Xochimilco Campus, Mexico City 04960, Mexico
- Correspondence:
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8
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Tabak BA, Leng G, Szeto A, Parker KJ, Verbalis JG, Ziegler TE, Lee MR, Neumann ID, Mendez AJ. Advances in human oxytocin measurement: challenges and proposed solutions. Mol Psychiatry 2023; 28:127-140. [PMID: 35999276 PMCID: PMC9812775 DOI: 10.1038/s41380-022-01719-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 07/18/2022] [Accepted: 07/21/2022] [Indexed: 01/09/2023]
Abstract
Oxytocin, a neuropeptide known for its role in reproduction and socioemotional processes, may hold promise as a therapeutic agent in treating social impairments in patient populations. However, research has yet to uncover precisely how to manipulate this system for clinical benefit. Moreover, inconsistent use of standardized and validated oxytocin measurement methodologies-including the design and study of hormone secretion and biochemical assays-present unresolved challenges. Human studies measuring peripheral (i.e., in plasma, saliva, or urine) or central (i.e., in cerebrospinal fluid) oxytocin concentrations have involved very diverse methods, including the use of different assay techniques, further compounding this problem. In the present review, we describe the scientific value in measuring human endogenous oxytocin concentrations, common issues in biochemical analysis and study design that researchers face when doing so, and our recommendations for improving studies using valid and reliable methodologies.
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Affiliation(s)
- Benjamin A Tabak
- Department of Psychology, Southern Methodist University, Dallas, TX, USA.
| | - Gareth Leng
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Angela Szeto
- Department of Psychology, University of Miami, Coral Gables, FL, USA
| | - Karen J Parker
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Department of Comparative Medicine, Stanford University, Stanford, CA, USA
| | - Joseph G Verbalis
- Division of Endocrinology and Metabolism, Department of Medicine, Georgetown University Medical Center, Washington, DC, USA
| | - Toni E Ziegler
- Assay Services Unit and Institute for Clinical and Translational Research Core Laboratory, National Primate Research Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Mary R Lee
- Veterans Affairs Medical Center, Washington, DC, USA
| | - Inga D Neumann
- Department of Behaviour and Molecular Neurobiology, University of Regensburg, Regensburg, Germany
| | - Armando J Mendez
- Diabetes Research Institute, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL, USA
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9
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Leng G, Leng RI, Ludwig M. Oxytocin—a social peptide? Deconstructing the evidence. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210055. [PMID: 35858110 PMCID: PMC9272144 DOI: 10.1098/rstb.2021.0055] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In this paper, we analyse the claim that oxytocin is a ‘social neuropeptide’. This claim originated from evidence that oxytocin was instrumental in the initiation of maternal behaviour and it was extended to become the claim that oxytocin has a key role in promoting social interactions between individuals. We begin by considering the structure of the scientific literature on this topic, identifying closely interconnected clusters of papers on particular themes. We then analyse this claim by considering evidence of four types as generated by these clusters: (i) mechanistic studies in animal models, designed to understand the pathways involved in the behavioural effects of centrally administered oxytocin; (ii) evidence from observational studies indicating an association between oxytocin signalling pathways and social behaviour; (iii) evidence from intervention studies, mainly involving intranasal oxytocin administration; and (iv) evidence from translational studies of patients with disorders of social behaviour. We then critically analyse the most highly cited papers in each segment of the evidence; we conclude that, if these represent the best evidence, then the evidence for the claim is weak. This article is part of the theme issue ‘Interplays between oxytocin and other neuromodulators in shaping complex social behaviours’.
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Affiliation(s)
- Gareth Leng
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, Edinburgh EH8 9XD, UK
| | - Rhodri I. Leng
- Department of Science, Technology and Innovation Studies, University of Edinburgh, Edinburgh, UK
| | - Mike Ludwig
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, 15 George Square, Edinburgh EH8 9XD, UK
- Faculty of Health Sciences, Centre for Neuroendocrinology, University of Pretoria, Pretoria, South Africa
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10
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Carter CS, Kingsbury MA. Oxytocin and oxygen: the evolution of a solution to the ‘stress of life’. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210054. [PMID: 35856299 PMCID: PMC9272143 DOI: 10.1098/rstb.2021.0054] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Oxytocin (OT) and the OT receptor occupy essential roles in our current understanding of mammalian evolution, survival, sociality and reproduction. This narrative review examines the hypothesis that many functions attributed to OT can be traced back to conditions on early Earth, including challenges associated with managing life in the presence of oxygen and other basic elements, including sulfur. OT regulates oxidative stress and inflammation especially through effects on the mitochondria. A related nonapeptide, vasopressin, as well as molecules in the hypothalamic–pituitary–adrenal axis, including the corticotropin-releasing hormone family of molecules, have a broad set of functions that interact with OT. Interactions among these molecules have roles in the causes and consequence of social behaviour and the management of threat, fear and stress. Here, we discuss emerging evidence suggesting that unique properties of the OT system allowed vertebrates, and especially mammals, to manage over-reactivity to the ‘side effects’ of oxygen, including inflammation, oxidation and free radicals, while also supporting high levels of sociality and a perception of safety. This article is part of the theme issue ‘Interplays between oxytocin and other neuromodulators in shaping complex social behaviours’.
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Affiliation(s)
- C. Sue Carter
- Kinsey Institute, Indiana University, Bloomington, IN 47405, USA
- Department of Psychology, University of Virginia, Charlottesville, VA 22904, USA
| | - Marcy A. Kingsbury
- Lurie Center for Autism, Mass General Hospital for Children, Harvard University Medical School, Charlestown, Boston, MA 02129, USA
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11
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Hering A, Jieu B, Jones A, Muttenthaler M. Approaches to Improve the Quantitation of Oxytocin in Human Serum by Mass Spectrometry. Front Chem 2022; 10:889154. [PMID: 35755255 PMCID: PMC9218718 DOI: 10.3389/fchem.2022.889154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 05/03/2022] [Indexed: 11/26/2022] Open
Abstract
The neuropeptide oxytocin (OT) regulates several peripheral and central functions and is a molecule of interest in psychiatric diseases such as autism spectrum disorder, schizophrenia, anxiety and depression. The study of OT in human serum samples is however hampered by inconsistent sample preparation and analysis as well as low endogenous blood concentration (1-10 pM). This results in varying reports on OT's blood levels and interpretation of OT's role in different (patho)physiological states. Quantitative mass spectrometry (MS) is a highly promising technology to address this problem but still requires large sample volumes to achieve adequate sensitivity and reliability for the quantitation of compounds at low concentrations. We therefore systematically evaluated sample preparation methods for MS to achieve a reliable sample preparation protocol with good peptide recovery, minimal matrix effects and good overall method efficiency in line with FDA guidelines for bioanalytic method development and validation. Additionally, we investigated a strategy to improve the ionization efficiency of OT by adding charged and/or hydrophobic moieties to OT to improve the lower limit of quantitation. Optimized sample preparation in combination with OT modification with a quaternary pyridinium ion improved the sensitivity of OT by ∼40-fold on a tandem triple quadrupole mass spectrometer (API4000 QTRAP), resulting in a lower limit of quantitation of 5 pM in water (linear range 5 pM - 1 mM) and 2 nM in human serum (linear range 2 nM - 1 mM) compared to 200 pM in water and 86 nM in serum with unmodified OT. This approach and protocol provide a solid foundation towards method development for OT quantitation using MS, which should be of high value for fundamental research as well as clinical monitoring of OT upon drug treatments.
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Affiliation(s)
- Anke Hering
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Beverly Jieu
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Alun Jones
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Markus Muttenthaler
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
- Institute of Biological Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria
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12
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Triki Z, Daughters K, De Dreu CKW. Oxytocin has 'tend-and-defend' functionality in group conflict across social vertebrates. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210137. [PMID: 35369742 PMCID: PMC8977669 DOI: 10.1098/rstb.2021.0137] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Across vertebrate species, intergroup conflict confronts individuals with a tension between group interests best served by participation in conflict and personal interest best served by not participating. Here, we identify the neurohormone oxytocin as pivotal to the neurobiological regulation of this tension in distinctly different group-living vertebrates, including fishes, birds, rodents, non-human primates and humans. In the context of intergroup conflict, a review of emerging work on pro-sociality suggests that oxytocin and its fish and birds homologues, isotocin and mesotocin, respectively, can elicit participation in group conflict and aggression. This is because it amplifies (i) concern for the interests of genetically related or culturally similar ‘in-group’ others and (ii) willingness to defend against outside intruders and enemy conspecifics. Across a range of social vertebrates, oxytocin can induce aggressive behaviour to ‘tend-and-defend’ the in-group during intergroup contests. This article is part of the theme issue ‘Intergroup conflict across taxa’.
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Affiliation(s)
- Zegni Triki
- Department of Zoology, Stockholm University, Stockholm, Sweden
| | | | - Carsten K W De Dreu
- Institute of Psychology, Leiden University, Leiden, The Netherlands.,Center for Research in Experimental Economics and Political Decision Making, University of Amsterdam, Amsterdam, The Netherlands
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13
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Sasaki S, Oba K, Kodera Y, Itakura M, Shichiri M. ANGT_HUMAN[448–462], an Anorexigenic Peptide Identified using Plasma Peptidomics. J Endocr Soc 2022; 6:bvac082. [PMID: 35702602 PMCID: PMC9184509 DOI: 10.1210/jendso/bvac082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Indexed: 11/19/2022] Open
Abstract
Abstract
The discovery of bioactive peptides is an important research target that enables the elucidation of the pathophysiology of human diseases and provides seeds for drug discovery. Using a large number of native peptides previously identified using plasma peptidomics technology, we sequentially synthesized selected sequences and subjected them to functional screening using human cultured cells. A 15-amino-acid residue proangiotensinogen-derived peptide, designated ANGT_HUMAN[448–462], elicited cellular responses and bound to cultured human cells. Synthetic fluorescent-labeled and biotinylated ANGT_HUMAN[448–462] peptides were rendered to bind to cell- and tissue-derived proteins and peptide-cell protein complexes were retrieved and analyzed using liquid chromatography-tandem mass spectrometry, revealing the β-subunit of ATP synthase as its cell-surface binding protein. Because ATP synthase mediates the effects of anorexigenic peptides, the ability of ANGT_HUMAN[448–462] to modulate eating behavior in mice was investigated. Both intraperitoneal and intracerebroventricular injections of low doses of ANGT_HUMAN[448–462] suppressed spontaneous food and water intake throughout the dark phase of the diurnal cycle without affecting locomotor activity. Immunoreactive ANGT_HUMAN[448–462], distributed throughout human tissues and in human-derived cells, is mostly co-localized with angiotensin II and is occasionally present separately from angiotensin II. In this study, an anorexigenic peptide, ANGT_HUMAN[448–462], was identified by exploring cell surface target proteins of the human native peptides identified using plasma peptidomics.
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Affiliation(s)
- Sayaka Sasaki
- Department of Endocrinology, Diabetes and Metabolism, Kitasato University School of Medicine Kanagawa 252-0374, Japan
| | - Kazuhito Oba
- Department of Endocrinology, Diabetes and Metabolism, Kitasato University School of Medicine Kanagawa 252-0374, Japan
| | - Yoshio Kodera
- Department of Physics, Kitasato University School of Science, Kanagawa 252-0373, Japan
- Center for Disease Proteomics, Kitasato University School of Science, Kanagawa 252-0373, Japan
| | - Makoto Itakura
- Department of Biochemistry, Kitasato University School of Medicine, Kanagawa 252-0374, Japan
| | - Masayoshi Shichiri
- Department of Endocrinology, Diabetes and Metabolism, Kitasato University School of Medicine Kanagawa 252-0374, Japan
- Department of Diabetes, Endocrinology and Metabolism, Tokyo Kyosai Hospital, Tokyo 153-8934, Japan
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14
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Pichugina YA, Maksimova IV, Berezovskaya MA, Afanaseva NA, Pichugin AB, Dmitrenko DV, Timechko EE, Salmina AB, Lopatina OL. Salivary oxytocin in autistic patients and in patients with intellectual disability. Front Psychiatry 2022; 13:969674. [PMID: 36506430 PMCID: PMC9729552 DOI: 10.3389/fpsyt.2022.969674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 10/27/2022] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Assessing the role of oxytocin (OT) in the regulation of social interaction is a promising area that opens up new opportunities for studying the mechanisms of developing autism spectrum disorders (ASD). AIM To assess the correlation between the salivary OT level and age-related and psychopathological symptoms of children with intellectual disability (ID) and ASD. METHODS We used the clinical and psychopathological method to assess the signs of ASD based on International Classification of Diseases (ICD-10), the severity of ASD was specified by the selected Russian type version "Childhood Autism Rating Scale" (CARS). Patients of both groups had an IQ score below 70 points. RESULTS The median and interquartile range of salivary OT levels in patients with ID and ASD were 23.897 [14.260-59.643] pg/mL, and in the group ID without ASD - Me = 50.896 [33.502-83.774] pg/mL (p = 0.001). The severity of ASD on the CARS scale Me = 51.5 [40.75-56.0] score in the group ID with ASD, and in the group ID without ASD-at the level of Me = 32 [27.0-38.0] points (p < 0.001). According to the results of correlation-regression analysis in the main group, a direct correlation was established between salivary OT level and a high degree of severity of ASD Rho = 0.435 (p = 0.005). There was no correlation between the salivary OT level and intellectual development in the group ID with ASD, Rho = 0.013 (p = 0.941) and we have found a relationship between oxytocin and intellectual development in the group ID without ASD, Rho = 0.297 (p = 0.005). There was no correlation between salivary OT and age, ASD and age. CONCLUSION The results of this study indicate that patients in the group ID with ASD demonstrated a lower level of salivary OT concentration and a direct relationship between the maximum values of this indicator and the severity of autistic disorders, in contrast to patients in the group ID without ASD.
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Affiliation(s)
- Yulia A Pichugina
- Department of Psychiatry and Narcology, Prof. V.F. Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Irina V Maksimova
- Department of Psychiatry and Narcology, Prof. V.F. Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Marina A Berezovskaya
- Department of Psychiatry and Narcology, Prof. V.F. Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Natalya A Afanaseva
- Department of Psychiatry and Narcology, Prof. V.F. Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Aleksey B Pichugin
- Social Neuroscience Laboratory, Prof. V.F. Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Diana V Dmitrenko
- Department of Medical Genetics of Clinical Neurophysiology, Institute of Postgraduate Education, Prof. V.F. Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, Russia.,Medical Genetic Laboratory, Prof. V.F. Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Elena E Timechko
- Medical Genetic Laboratory, Prof. V.F. Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Alla B Salmina
- Laboratory of Experimental Brain Cytology, Department of Brain Studies, Research Center of Neurology, Moscow, Russia.,Research Institute of Molecular Medicine and Pathobiochemistry, Prof. V.F. Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, Russia
| | - Olga L Lopatina
- Social Neuroscience Laboratory, Prof. V.F. Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, Russia.,Department of Biochemistry, Medical, Pharmaceutical and Toxicological Chemistry, Prof. V.F. Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, Russia
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15
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Grønbæk-Thorsen F, Jensen C, Østergaard J, Møller LH, Gammelgaard B. Comparison of external calibration and isotope dilution LC-ICP-MS/MS for quantitation of oxytocin and its selenium analogue in human plasma. Anal Bioanal Chem 2021; 413:6479-6488. [PMID: 34458946 DOI: 10.1007/s00216-021-03611-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 06/22/2021] [Accepted: 08/09/2021] [Indexed: 12/17/2022]
Abstract
In the present study, a method for quantitation of the pharmaceutical peptide oxytocin (OT) and its diselenide-containing analogue (SeOT) in human plasma was developed using gradient elution LC-ICP-MS/MS. Plasma samples were precipitated with acetonitrile containing 1.0% TFA in a volume ratio of 1+3 (sample+precipitation agent) before analysis. Post-column isotope dilution analysis (IDA) was applied for quantitation and was compared with external calibration. Both calibration methods appeared to be fit for purpose regarding figures of merit including linearity, precision, LOD, LOQ and recovery. Analysis of OT and SeOT showed that selenium-based analysis is considerably more sensitive and selective compared to the sulfur-based analysis. Despite the relatively simpler setup of external calibration, IDA can be advantageous because it compensates for instrument drift and changes in organic solvent concentration. The method was applied for a stability study showing the degradation of OT and SeOT in plasma. The degradation of SeOT was faster than the degradation of OT in plasma. Thus, possible stability effects should be considered before replacing a disulfide bridge with a diselenide bridge or introducing a diselenide label in a potential drug.
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Affiliation(s)
- Freja Grønbæk-Thorsen
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark
| | - Camilla Jensen
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark
| | - Jesper Østergaard
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark
| | - Laura Hyrup Møller
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark
| | - Bente Gammelgaard
- Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark.
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16
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Kerem L, Lawson EA. The Effects of Oxytocin on Appetite Regulation, Food Intake and Metabolism in Humans. Int J Mol Sci 2021; 22:7737. [PMID: 34299356 PMCID: PMC8306733 DOI: 10.3390/ijms22147737] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 07/13/2021] [Accepted: 07/16/2021] [Indexed: 12/18/2022] Open
Abstract
The hypothalamic peptide oxytocin and its receptor are involved in a range of physiological processes, including parturition, lactation, cell growth, wound healing, and social behavior. More recently, increasing evidence has established the effects of oxytocin on food intake, energy expenditure, and peripheral metabolism. In this review, we provide a comprehensive description of the central oxytocinergic system in which oxytocin acts to shape eating behavior and metabolism. Next, we discuss the peripheral beneficial effects oxytocin exerts on key metabolic organs, including suppression of visceral adipose tissue inflammation, skeletal muscle regeneration, and bone tissue mineralization. A brief summary of oxytocin actions learned from animal models is presented, showing that weight loss induced by chronic oxytocin treatment is related not only to its anorexigenic effects, but also to the resulting increase in energy expenditure and lipolysis. Following an in-depth discussion on the technical challenges related to endogenous oxytocin measurements in humans, we synthesize data related to the association between endogenous oxytocin levels, weight status, metabolic syndrome, and bone health. We then review clinical trials showing that in humans, acute oxytocin administration reduces food intake, attenuates fMRI activation of food motivation brain areas, and increases activation of self-control brain regions. Further strengthening the role of oxytocin in appetite regulation, we review conditions of hypothalamic insult and certain genetic pathologies associated with oxytocin depletion that present with hyperphagia, extreme weight gain, and poor metabolic profile. Intranasal oxytocin is currently being evaluated in human clinical trials to learn whether oxytocin-based therapeutics can be used to treat obesity and its associated sequela. At the end of this review, we address the fundamental challenges that remain in translating this line of research to clinical care.
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Affiliation(s)
- Liya Kerem
- Neuroendocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA;
- Division of Pediatric Endocrinology, Massachusetts General Hospital for Children, Boston, MA 02114, USA
| | - Elizabeth A. Lawson
- Neuroendocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA;
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17
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Masaki T, Kodera Y, Terasaki M, Fujimoto K, Hirano T, Shichiri M. GIP_HUMAN[22-51] is a new proatherogenic peptide identified by native plasma peptidomics. Sci Rep 2021; 11:14470. [PMID: 34262109 PMCID: PMC8280211 DOI: 10.1038/s41598-021-93862-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 07/01/2021] [Indexed: 12/25/2022] Open
Abstract
We recently established a new plasma peptidomic technique and comprehensively identified a large number of low-molecular weight and low-abundance native peptides using a single drop of human plasma. To discover a novel polypeptide that potently modulates the cardiovascular system, we performed a bioinformatics analysis of the large-scale identification results, sequentially synthesized the selected peptide sequences, tested their biological activities, and identified a 30-amino-acid proatherogenic peptide, GIP_HUMAN[22-51], as a potent proatherosclerotic peptide hormone. GIP_HUMAN[22-51] has a common precursor with the glucose-dependent insulinotropic polypeptide (GIP) and is located immediately N-terminal to GIP. Chronic infusion of GIP_HUMAN[22-51] into ApoE-/- mice accelerated the development of aortic atherosclerotic lesions, which were inhibited by co-infusions with an anti-GIP_HUMAN[22-51] antibody. GIP_HUMAN[22-51] increased the serum concentrations of many inflammatory and proatherogenic proteins, whereas neutralising antibodies reduced their levels. GIP_HUMAN[22-51] induced IκB-α degradation and nuclear translocation of NF-κB in human vascular endothelial cells and macrophages. Immunoreactive GIP_HUMAN[22-51] was detected in human tissues but there was no colocalization with the GIP. The plasma GIP_HUMAN[22-51] concentration in healthy humans determined using a stable-isotope tagged peptide was approximately 0.6 nM. This study discovered a novel endogenous proatherogenic peptide by using a human plasma native peptidomic resource.
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Affiliation(s)
- Tsuguto Masaki
- Department of Endocrinology, Diabetes and Metabolism, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
| | - Yoshio Kodera
- Department of Physics, Center for Disease Proteomics, Kitasato University School of Science, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Michishige Terasaki
- Division of Diabetes, Metabolism and Endocrinology, Department of Medicine, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555, Japan
| | - Kazumi Fujimoto
- Department of Endocrinology, Diabetes and Metabolism, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
- Department of Physics, Center for Disease Proteomics, Kitasato University School of Science, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Tsutomu Hirano
- Division of Diabetes, Metabolism and Endocrinology, Department of Medicine, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555, Japan
| | - Masayoshi Shichiri
- Department of Endocrinology, Diabetes and Metabolism, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan.
- Tokyo Kyosai Hospital, 2-3-8 Nakameguro, Meguro-ku, Tokyo, 153-8934, Japan.
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18
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Wirobski G, Schaebs FS, Range F, Marshall-Pescini S, Deschner T. Analytical and physiological validation of an enzyme immunoassay to measure oxytocin in dog, wolf, and human urine samples. Sci Rep 2021; 11:12793. [PMID: 34140610 PMCID: PMC8211859 DOI: 10.1038/s41598-021-92356-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/31/2021] [Indexed: 02/03/2023] Open
Abstract
Oxytocin (OT) promotes pro-sociality, bonding, and cooperation in a variety of species. Measuring oxytocin metabolite (OTM) concentrations in urine or saliva provides intriguing opportunities to study human and animal behaviour with minimal disturbance. However, a thorough validation of analytical methods and an assessment of the physiological significance of these measures are essential. We conducted an analytical validation of a commercial Enzyme Immunoassay (EIA; Arbor OT assay kit) to measure OTM concentrations in dog, wolf, and human urine samples. To test the assay's ability to detect changes in OTM concentrations, we administered oxytocin intranasally to 14 dogs. Assay performance with regard to parallelism was acceptable. Assay accuracy and extraction efficiency for dog and wolf samples were comparable to a previously validated assay (Enzo OT assay kit) but variation was smaller for human samples. Binding sensitivity and antibody specificity were better in the Arbor assay. Average OTM concentrations were more than twice as high as in comparable samples measured with the Enzo assay, highlighting a lack of comparability of absolute values between different assays. Changes in OTM concentrations after intranasal treatment were detected reliably. The Arbor assay met requirements of a "fit-for-purpose" validation with improvement of several parameters compared to the Enzo assay.
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Affiliation(s)
- G Wirobski
- Domestication Lab, Wolf Science Center, Konrad-Lorenz-Institute for Ethology, University of Veterinary Medicine, Veterinaerplatz 1, 1210, Vienna, Austria.
| | - F S Schaebs
- University of Leipzig, ZLS, Prager Str. 34, 04317, Leipzig, Germany
| | - F Range
- Domestication Lab, Wolf Science Center, Konrad-Lorenz-Institute for Ethology, University of Veterinary Medicine, Veterinaerplatz 1, 1210, Vienna, Austria
| | - S Marshall-Pescini
- Domestication Lab, Wolf Science Center, Konrad-Lorenz-Institute for Ethology, University of Veterinary Medicine, Veterinaerplatz 1, 1210, Vienna, Austria
| | - T Deschner
- Interim Group Primatology, Max-Planck-Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany
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19
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Carter CS, Kenkel WM, MacLean EL, Wilson SR, Perkeybile AM, Yee JR, Ferris CF, Nazarloo HP, Porges SW, Davis JM, Connelly JJ, Kingsbury MA. Is Oxytocin "Nature's Medicine"? Pharmacol Rev 2021; 72:829-861. [PMID: 32912963 PMCID: PMC7495339 DOI: 10.1124/pr.120.019398] [Citation(s) in RCA: 187] [Impact Index Per Article: 62.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Oxytocin is a pleiotropic, peptide hormone with broad implications for general health, adaptation, development, reproduction, and social behavior. Endogenous oxytocin and stimulation of the oxytocin receptor support patterns of growth, resilience, and healing. Oxytocin can function as a stress-coping molecule, an anti-inflammatory, and an antioxidant, with protective effects especially in the face of adversity or trauma. Oxytocin influences the autonomic nervous system and the immune system. These properties of oxytocin may help explain the benefits of positive social experiences and have drawn attention to this molecule as a possible therapeutic in a host of disorders. However, as detailed here, the unique chemical properties of oxytocin, including active disulfide bonds, and its capacity to shift chemical forms and bind to other molecules make this molecule difficult to work with and to measure. The effects of oxytocin also are context-dependent, sexually dimorphic, and altered by experience. In part, this is because many of the actions of oxytocin rely on its capacity to interact with the more ancient peptide molecule, vasopressin, and the vasopressin receptors. In addition, oxytocin receptor(s) are epigenetically tuned by experience, especially in early life. Stimulation of G-protein–coupled receptors triggers subcellular cascades allowing these neuropeptides to have multiple functions. The adaptive properties of oxytocin make this ancient molecule of special importance to human evolution as well as modern medicine and health; these same characteristics also present challenges to the use of oxytocin-like molecules as drugs that are only now being recognized.
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Affiliation(s)
- C Sue Carter
- Kinsey Institute, Indiana University, Bloomington, Indiana (C.S.C., W.M.K., A.M.P., H.P.N., S.W.P.); School of Anthropology, Department of Psychology, and College of Veterinary Medicine, University of Arizona, Tucson, Arizona (E.L.M.); Department of Chemistry, University of Oslo, Oslo, Norway (S.R.W.); Institute of Animal Welfare Science, University of Veterinary Medicine, Vienna, Austria (J.R.Y.); Departments of Psychology and Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (C.F.F.); Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois (J.M.D.); Department of Psychology, University of Virginia, Charlottesville, Virginia (J.J.C.); and Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Charleston, Massachusetts (M.A.K.)
| | - William M Kenkel
- Kinsey Institute, Indiana University, Bloomington, Indiana (C.S.C., W.M.K., A.M.P., H.P.N., S.W.P.); School of Anthropology, Department of Psychology, and College of Veterinary Medicine, University of Arizona, Tucson, Arizona (E.L.M.); Department of Chemistry, University of Oslo, Oslo, Norway (S.R.W.); Institute of Animal Welfare Science, University of Veterinary Medicine, Vienna, Austria (J.R.Y.); Departments of Psychology and Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (C.F.F.); Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois (J.M.D.); Department of Psychology, University of Virginia, Charlottesville, Virginia (J.J.C.); and Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Charleston, Massachusetts (M.A.K.)
| | - Evan L MacLean
- Kinsey Institute, Indiana University, Bloomington, Indiana (C.S.C., W.M.K., A.M.P., H.P.N., S.W.P.); School of Anthropology, Department of Psychology, and College of Veterinary Medicine, University of Arizona, Tucson, Arizona (E.L.M.); Department of Chemistry, University of Oslo, Oslo, Norway (S.R.W.); Institute of Animal Welfare Science, University of Veterinary Medicine, Vienna, Austria (J.R.Y.); Departments of Psychology and Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (C.F.F.); Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois (J.M.D.); Department of Psychology, University of Virginia, Charlottesville, Virginia (J.J.C.); and Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Charleston, Massachusetts (M.A.K.)
| | - Steven R Wilson
- Kinsey Institute, Indiana University, Bloomington, Indiana (C.S.C., W.M.K., A.M.P., H.P.N., S.W.P.); School of Anthropology, Department of Psychology, and College of Veterinary Medicine, University of Arizona, Tucson, Arizona (E.L.M.); Department of Chemistry, University of Oslo, Oslo, Norway (S.R.W.); Institute of Animal Welfare Science, University of Veterinary Medicine, Vienna, Austria (J.R.Y.); Departments of Psychology and Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (C.F.F.); Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois (J.M.D.); Department of Psychology, University of Virginia, Charlottesville, Virginia (J.J.C.); and Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Charleston, Massachusetts (M.A.K.)
| | - Allison M Perkeybile
- Kinsey Institute, Indiana University, Bloomington, Indiana (C.S.C., W.M.K., A.M.P., H.P.N., S.W.P.); School of Anthropology, Department of Psychology, and College of Veterinary Medicine, University of Arizona, Tucson, Arizona (E.L.M.); Department of Chemistry, University of Oslo, Oslo, Norway (S.R.W.); Institute of Animal Welfare Science, University of Veterinary Medicine, Vienna, Austria (J.R.Y.); Departments of Psychology and Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (C.F.F.); Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois (J.M.D.); Department of Psychology, University of Virginia, Charlottesville, Virginia (J.J.C.); and Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Charleston, Massachusetts (M.A.K.)
| | - Jason R Yee
- Kinsey Institute, Indiana University, Bloomington, Indiana (C.S.C., W.M.K., A.M.P., H.P.N., S.W.P.); School of Anthropology, Department of Psychology, and College of Veterinary Medicine, University of Arizona, Tucson, Arizona (E.L.M.); Department of Chemistry, University of Oslo, Oslo, Norway (S.R.W.); Institute of Animal Welfare Science, University of Veterinary Medicine, Vienna, Austria (J.R.Y.); Departments of Psychology and Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (C.F.F.); Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois (J.M.D.); Department of Psychology, University of Virginia, Charlottesville, Virginia (J.J.C.); and Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Charleston, Massachusetts (M.A.K.)
| | - Craig F Ferris
- Kinsey Institute, Indiana University, Bloomington, Indiana (C.S.C., W.M.K., A.M.P., H.P.N., S.W.P.); School of Anthropology, Department of Psychology, and College of Veterinary Medicine, University of Arizona, Tucson, Arizona (E.L.M.); Department of Chemistry, University of Oslo, Oslo, Norway (S.R.W.); Institute of Animal Welfare Science, University of Veterinary Medicine, Vienna, Austria (J.R.Y.); Departments of Psychology and Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (C.F.F.); Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois (J.M.D.); Department of Psychology, University of Virginia, Charlottesville, Virginia (J.J.C.); and Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Charleston, Massachusetts (M.A.K.)
| | - Hossein P Nazarloo
- Kinsey Institute, Indiana University, Bloomington, Indiana (C.S.C., W.M.K., A.M.P., H.P.N., S.W.P.); School of Anthropology, Department of Psychology, and College of Veterinary Medicine, University of Arizona, Tucson, Arizona (E.L.M.); Department of Chemistry, University of Oslo, Oslo, Norway (S.R.W.); Institute of Animal Welfare Science, University of Veterinary Medicine, Vienna, Austria (J.R.Y.); Departments of Psychology and Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (C.F.F.); Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois (J.M.D.); Department of Psychology, University of Virginia, Charlottesville, Virginia (J.J.C.); and Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Charleston, Massachusetts (M.A.K.)
| | - Stephen W Porges
- Kinsey Institute, Indiana University, Bloomington, Indiana (C.S.C., W.M.K., A.M.P., H.P.N., S.W.P.); School of Anthropology, Department of Psychology, and College of Veterinary Medicine, University of Arizona, Tucson, Arizona (E.L.M.); Department of Chemistry, University of Oslo, Oslo, Norway (S.R.W.); Institute of Animal Welfare Science, University of Veterinary Medicine, Vienna, Austria (J.R.Y.); Departments of Psychology and Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (C.F.F.); Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois (J.M.D.); Department of Psychology, University of Virginia, Charlottesville, Virginia (J.J.C.); and Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Charleston, Massachusetts (M.A.K.)
| | - John M Davis
- Kinsey Institute, Indiana University, Bloomington, Indiana (C.S.C., W.M.K., A.M.P., H.P.N., S.W.P.); School of Anthropology, Department of Psychology, and College of Veterinary Medicine, University of Arizona, Tucson, Arizona (E.L.M.); Department of Chemistry, University of Oslo, Oslo, Norway (S.R.W.); Institute of Animal Welfare Science, University of Veterinary Medicine, Vienna, Austria (J.R.Y.); Departments of Psychology and Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (C.F.F.); Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois (J.M.D.); Department of Psychology, University of Virginia, Charlottesville, Virginia (J.J.C.); and Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Charleston, Massachusetts (M.A.K.)
| | - Jessica J Connelly
- Kinsey Institute, Indiana University, Bloomington, Indiana (C.S.C., W.M.K., A.M.P., H.P.N., S.W.P.); School of Anthropology, Department of Psychology, and College of Veterinary Medicine, University of Arizona, Tucson, Arizona (E.L.M.); Department of Chemistry, University of Oslo, Oslo, Norway (S.R.W.); Institute of Animal Welfare Science, University of Veterinary Medicine, Vienna, Austria (J.R.Y.); Departments of Psychology and Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (C.F.F.); Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois (J.M.D.); Department of Psychology, University of Virginia, Charlottesville, Virginia (J.J.C.); and Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Charleston, Massachusetts (M.A.K.)
| | - Marcy A Kingsbury
- Kinsey Institute, Indiana University, Bloomington, Indiana (C.S.C., W.M.K., A.M.P., H.P.N., S.W.P.); School of Anthropology, Department of Psychology, and College of Veterinary Medicine, University of Arizona, Tucson, Arizona (E.L.M.); Department of Chemistry, University of Oslo, Oslo, Norway (S.R.W.); Institute of Animal Welfare Science, University of Veterinary Medicine, Vienna, Austria (J.R.Y.); Departments of Psychology and Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts (C.F.F.); Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois (J.M.D.); Department of Psychology, University of Virginia, Charlottesville, Virginia (J.J.C.); and Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Charleston, Massachusetts (M.A.K.)
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20
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Abstract
The hypothalamic peptide oxytocin has been increasingly recognized as a hormone and neurotransmitter with important effects on energy intake, metabolism, and body weight and is under investigation as a potential novel therapeutic agent for obesity. The main neurons producing oxytocin and expressing the oxytocin receptor are strategically located in brain areas known to be critically involved in homeostatic energy balance as well as hedonic and motivational aspects of eating behavior. In this chapter, we will review the central and peripheral physiology of oxytocin and the interaction of oxytocin with key hormones and neural circuitries that affect food intake and metabolism. Next, we will synthesize the available data on endogenous oxytocin levels related to caloric intake, body weight, and metabolic status. We will then review the effects of exogenous oxytocin administration on eating behavior, body weight, and metabolism in humans, including in healthy individuals as well as specific populations with suspected perturbations involving oxytocin pathways. Finally, we will address the promise and fundamental challenges of translating this line of research to clinical care.
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Affiliation(s)
- Liya Kerem
- Neuroendocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States; Division of Pediatric Endocrinology, Massachusetts General Hospital for Children, Boston, MA, United States
| | - Elizabeth A Lawson
- Neuroendocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States.
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21
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Development of Magnetic Nanobeads Modified by Artificial Fluorescent Peptides for the Highly Sensitive and Selective Analysis of Oxytocin. SENSORS 2020; 20:s20205956. [PMID: 33096804 PMCID: PMC7588987 DOI: 10.3390/s20205956] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 10/20/2020] [Indexed: 12/18/2022]
Abstract
We describe two novel fluorescent peptides (compounds 1 and 2) targeting oxytocin with a boron-dipyrromethenyl group as the fluorophore bound to an artificial peptide based on the oxytocin receptor, and their application for the analysis of oxytocin levels in human serum using nanometer-sized magnetic beads modified by fluorescent peptides (FMB-1 and FMB-2). Under the optimized experimental protocols, FMB-1 and FMB-2 emitted low levels of fluorescence but emitted much higher levels of fluorescence when associated with oxytocin. The detection limit of oxytocin by FMB-2 was 0.4 pM, which is approximately 37.5 times higher than that of conventional methods, such as ELISA. Using these fluorescent sensors, oxytocin was specifically detected over a wide linear range with high sensitivity, good reusability, stability, precision, and reproducibility. This fluorescent sensor-based detection system thus enabled the measurement of oxytocin levels in human serum, which has widespread applications for oxytocin assays across varied research fields.
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22
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Harvey AR. Links Between the Neurobiology of Oxytocin and Human Musicality. Front Hum Neurosci 2020; 14:350. [PMID: 33005139 PMCID: PMC7479205 DOI: 10.3389/fnhum.2020.00350] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 08/04/2020] [Indexed: 12/22/2022] Open
Abstract
The human species possesses two complementary, yet distinct, universal communication systems—language and music. Functional imaging studies have revealed that some core elements of these two systems are processed in closely related brain regions, but there are also clear differences in brain circuitry that likely underlie differences in functionality. Music affects many aspects of human behavior, especially in encouraging prosocial interactions and promoting trust and cooperation within groups of culturally compatible but not necessarily genetically related individuals. Music, presumably via its impact on the limbic system, is also rewarding and motivating, and music can facilitate aspects of learning and memory. In this review these special characteristics of music are considered in light of recent research on the neuroscience of the peptide oxytocin, a hormone that has both peripheral and central actions, that plays a role in many complex human behaviors, and whose expression has recently been reported to be affected by music-related activities. I will first briefly discuss what is currently known about the peptide’s physiological actions on neurons and its interactions with other neuromodulator systems, then summarize recent advances in our knowledge of the distribution of oxytocin and its receptor (OXTR) in the human brain. Next, the complex links between oxytocin and various social behaviors in humans are considered. First, how endogenous oxytocin levels relate to individual personality traits, and then how exogenous, intranasal application of oxytocin affects behaviors such as trust, empathy, reciprocity, group conformity, anxiety, and overall social decision making under different environmental conditions. It is argued that many of these characteristics of oxytocin biology closely mirror the diverse effects that music has on human cognition and emotion, providing a link to the important role music has played throughout human evolutionary history and helping to explain why music remains a special prosocial human asset. Finally, it is suggested that there is a potential synergy in combining oxytocin- and music-based strategies to improve general health and aid in the treatment of various neurological dysfunctions.
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Affiliation(s)
- Alan R Harvey
- School of Human Sciences, The University of Western Australia, Perron Institute for Neurological and Translational Science, Perth, WA, Australia
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23
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Franke AA, Li X, Dabalos C, Lai JF. Improved oxytocin analysis from human serum and urine by orbitrap ESI-LC-HRAM-MS. Drug Test Anal 2020; 12:846-852. [PMID: 32100408 DOI: 10.1002/dta.2783] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 02/21/2020] [Accepted: 02/23/2020] [Indexed: 01/30/2023]
Abstract
Native circulating oxytocin (OT) levels in non-pregnant/non-lactating/non-medicated humans are very low (≤ 8 pg/mL). The lower limit of detection (LLOD) of our previous liquid chromatography mass spectrometry (LC-MS) method (10-25 pg/mL) precluded their quantification in serum and urine. Thus, we sought to improve the LC-MS sensitivity of OT measurements in these matrices by hydrophobic tagging and solid phase extraction (SPE). In the former approach, OT was reduced then alkylated with N-alkyl acetamide (C12, C14, C16, and C18) tags or derivatized using sulfonyl chloride-based reagents. In the latter approach, native OT in serum and urine was concentrated by offline SPE using gradient acetonitrile washings after first crashing with acetonitrile. Peak urinary eluate fractions were further concentrated online then analyzed by orbitrap-based LC-MS with electrospray ionization. All hydrophobic OT derivatives had lower sensitivity than native OT. Washing with a water-acetonitrile gradient during SPE improved the LLOD of OT in spiked serum to 2.5 pg/mL, while adding a subsequent online-concentration step improved the LLOD in spiked urine to 1-5 pg/mL and allowed us to detect OT in urine from lactating women. We were unable to improve the sensitivity of OT measurements by hydrophobic tagging or by derivatization using sulfonyl chloride-based reagents. However, we were successful in improving the sensitivity of native OT measurements in serum and urine 2- and 5-fold, respectively, from our previous orbitrap-based LC-MS method. Offline SPE was mandatory for both matrices and a subsequent online-concentration step was required for urine.
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Affiliation(s)
- Adrian A Franke
- University of Hawaii Cancer Center, Analytical Biochemistry Shared Resource, Honolulu, Hawaii
| | - Xingnan Li
- University of Hawaii Cancer Center, Analytical Biochemistry Shared Resource, Honolulu, Hawaii
| | - Chester Dabalos
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii
| | - Jennifer F Lai
- University of Hawaii Cancer Center, Analytical Biochemistry Shared Resource, Honolulu, Hawaii
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24
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MacLean EL, Wilson SR, Martin WL, Davis JM, Nazarloo HP, Carter CS. Challenges for measuring oxytocin: The blind men and the elephant? Psychoneuroendocrinology 2019; 107:225-231. [PMID: 31163380 PMCID: PMC6634994 DOI: 10.1016/j.psyneuen.2019.05.018] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/10/2019] [Accepted: 05/14/2019] [Indexed: 12/31/2022]
Abstract
Since its discovery more than a century ago, oxytocin has become one of the most intensively studied molecules in behavioral biology. In the last five years, Psychoneuroendocrinology has published more than 500 articles with oxytocin in the title, with many of these articles including measures of endogenous oxytocin concentrations. Despite longstanding interest, methods of measuring endogenous oxytocin are still in active development. The widely varying oxytocin concentrations detected by different approaches to measurement - and lack of correlation among these techniques - has led to controversy and confusion. We identify features of oxytocin that may help to explain why various approaches may be differentially sensitive to diverse conformational states of the oxytocin molecule. We propose that discrepancies in data generated by different methods of measurement are not necessarily an indicator that some methods are valid whereas others are not. Rather, we propose that current challenges in the measurement of oxytocin may be analogous to the parable of the blind men and the elephant, with different methods of sample preparation and measurement being sensitive to different states in which the oxytocin molecule can exist.
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Affiliation(s)
- Evan L MacLean
- School of Anthropology, Department of Psychology, Cognitive Science Program, University of Arizona, United States.
| | - Steven Ray Wilson
- Department of Chemistry, Hybrid Technology Hub, Centre of Excellence, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Norway
| | | | - John M Davis
- Psychiatric Institute, University of Illinois at Chicago, United States
| | | | - C Sue Carter
- The Kinsey Institute, Indiana University, United States
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