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Alstrup AKO, Busk M, Dittrich A, Hansen K, Wang T, Damkjær M, Andersen JB, Lauridsen H. Special Challenges in PET Imaging of Ectothermic Vertebrates. Semin Nucl Med 2023; 53:577-585. [PMID: 37438172 DOI: 10.1053/j.semnuclmed.2023.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 06/18/2023] [Indexed: 07/14/2023]
Abstract
The bulk of biomedical positron emission tomography (PET)-scanning experiments are performed on mammals (ie, rodents, pigs, and dogs), and the technique is only infrequently applied to answer research questions in ectothermic vertebrates such as fish, amphibians, and reptiles. Nevertheless, many unique and interesting physiological characteristics in these ectothermic vertebrates could be addressed in detail through PET. The low metabolic rate of ectothermic animals, however, may compromise the validity of physiological and biochemical parameters derived from the images created by PET and other scanning modalities. Here, we review some of the considerations that should be taken into account when PET scanning fish, amphibians, and reptiles. We present specific results from our own experiments, many of which remain previously unpublished, and we draw on examples from the literature. We conclude that knowledge on the natural history and physiology of the species studied and an understanding of the limitations of the PET scanning techniques are necessary to avoid the design of faulty experiments and erroneous conclusions.
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Affiliation(s)
- Aage Kristian Olsen Alstrup
- Department of Nuclear Medicine and PET, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
| | - Morten Busk
- Experimental Clinical Oncology, Aarhus University, Denmark; Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark
| | - Anita Dittrich
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Kasper Hansen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Forensic Medicine, Aarhus University, Aarhus, Denmark; Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Tobias Wang
- Zoophysiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Mads Damkjær
- Department of Paediatrics and Adolescent Medicine, Lillebaelt Hospital, University Hospital of Southern Denmark, Kolding, Denmark; Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
| | | | - Henrik Lauridsen
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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Tajer B, Savage AM, Whited JL. The salamander blastema within the broader context of metazoan regeneration. Front Cell Dev Biol 2023; 11:1206157. [PMID: 37635872 PMCID: PMC10450636 DOI: 10.3389/fcell.2023.1206157] [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: 04/15/2023] [Accepted: 07/26/2023] [Indexed: 08/29/2023] Open
Abstract
Throughout the animal kingdom regenerative ability varies greatly from species to species, and even tissue to tissue within the same organism. The sheer diversity of structures and mechanisms renders a thorough comparison of molecular processes truly daunting. Are "blastemas" found in organisms as distantly related as planarians and axolotls derived from the same ancestral process, or did they arise convergently and independently? Is a mouse digit tip blastema orthologous to a salamander limb blastema? In other fields, the thorough characterization of a reference model has greatly facilitated these comparisons. For example, the amphibian Spemann-Mangold organizer has served as an amazingly useful comparative template within the field of developmental biology, allowing researchers to draw analogies between distantly related species, and developmental processes which are superficially quite different. The salamander limb blastema may serve as the best starting point for a comparative analysis of regeneration, as it has been characterized by over 200 years of research and is supported by a growing arsenal of molecular tools. The anatomical and evolutionary closeness of the salamander and human limb also add value from a translational and therapeutic standpoint. Tracing the evolutionary origins of the salamander blastema, and its relatedness to other regenerative processes throughout the animal kingdom, will both enhance our basic biological understanding of regeneration and inform our selection of regenerative model systems.
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Affiliation(s)
| | | | - Jessica L. Whited
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, United States
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Uemasu H, Ikuta H, Igawa T, Suzuki M, Kyakuno M, Iwata Y, Tazawa I, Ogino H, Satoh Y, Takeuchi T, Namba N, Hayashi T. Cryo-injury procedure-induced cardiac regeneration shows unique gene expression profiles in the newt Pleurodeles waltl. Dev Dyn 2021; 251:864-876. [PMID: 34964213 DOI: 10.1002/dvdy.450] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/09/2021] [Accepted: 12/13/2021] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Cardiac regeneration in the adult mouse is not substantial. Some vertebrates, such as newts and zebrafish, regenerate the heart throughout their lives. To understand how regenerative abilities differ among animal species, comparative research has been conducted in animals like mouse, zebrafish, and newt. For those purposes, cryo-injury is suitable as an experimental model for the pathological condition of human myocardial infarction. In fact, cryo-injury procedures are common in mouse and zebrafish. RESULTS In the present study, we induced cryo-damage on the ventricle in Iberian ribbed newts using a liquid nitrogen-chilled probe. We observed that the injured area recovered within 8 weeks, with remodeling of scar tissue and proliferation of cardiomyocytes. We investigated the subsequent recovery of cryo-injured and amputated tissues by comparative analysis of the gene expression profiles following these two procedures. CONCLUSION Notably, we established a cryo-injury procedure for the newt and confirmed that regeneration of the cryo-damaged myocardial tissue is achieved by changes in gene expression that are milder than those observed in the amputation model. Our results suggest that the cryo-injury method is suitable for comparing the process of cardiac regeneration in the newt with that in other animal models. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Hitoshi Uemasu
- Division of Pediatrics and Perinatology, School of Medicine, Faculty of Medicine, Tottori University Yonago, Tottori, Japan
| | - Hiromi Ikuta
- Amphibian Research Center, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan.,Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Takeshi Igawa
- Amphibian Research Center, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan.,Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Makoto Suzuki
- Amphibian Research Center, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan.,Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Mitsuki Kyakuno
- Amphibian Research Center, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan.,Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Yui Iwata
- Amphibian Research Center, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan.,Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Ichiro Tazawa
- Amphibian Research Center, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan.,Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Hajime Ogino
- Amphibian Research Center, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan.,Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Yukio Satoh
- Department of Biomedical Sciences, School of Life Sciences, Faculty of Medicine, Tottori University, Yonago, Tottori, Japan
| | - Takashi Takeuchi
- Department of Biomedical Sciences, School of Life Sciences, Faculty of Medicine, Tottori University, Yonago, Tottori, Japan
| | - Noriyuki Namba
- Division of Pediatrics and Perinatology, School of Medicine, Faculty of Medicine, Tottori University Yonago, Tottori, Japan
| | - Toshinori Hayashi
- Amphibian Research Center, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan.,Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
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