How do zebrafish regenerate their organs? 

Injuries to human organs, such as the limbs and the heart, result in persistent pathologic conditions. By contrast, zebrafish can completely reconstitute parts of their fins, hearts, retinas and spinal cords. Regeneration in zebrafish predominantly relies on the intrinsic plasticity of mature tissues. This property involves activation of the remaining tissue at the site of injury to promote cell division, cell migration and replacement of the missing structures. Which biological mechanisms guide the mature cells through the regeneration process? How do systemic factors modulate this process? Do regenerative programs of different organs rely on conserved mechanisms? In our research, we address these questions focusing on heart and fin regeneration in zebrafish. Our methods rely on pharmacological approaches and transgenic animals.

  • Self-repairing broken hearts

    Adult zebrafish can regenerate their hearts within 1 to 2 months after damage. Several years ago, our laboratory established a cryoinjury-induced myocardial infarction model in zebrafish, whereby a freezing-thawing procedure destroys approx. 20% of the ventricle. We have since identified several signaling pathways that are required for heart restoration. We also found specific extracellular matrix components that are beneficial for regeneration. Our experiments revealed that the myocardium adjacent to the injury undergoes dedifferentiation, during which embryonic cardiac programs become reactivated to give rise to new tissue. We also reported that the natural power of heart regeneration in zebrafish can be suppressed by a daily hour of stress, such as crowding. By contrast, preconditioning, the application of a small remote noxious stimulus before injury, boosts heart regeneration. We are currently investigating the regenerative capacity of specific cardiac cell populations and comparing the restorative programs of different fish species.

  • The art of fin regeneration

    The zebrafish fin is a multi-tissue appendage, the correct pattern and size of which can be restablished within 3 weeks after amputation. First, the fin margin is covered by a wound epithelium, and next a proliferative blastema arises by dedifferentiation of stump tissues near the amputation. Our laboratory identified signalling pathways that orchestrate proliferation, migration and patterning of different tissues in the regenerating fin. Furthermore, we identified that chromatin modification is critical for redifferentiation of blastema cells. Regarding extracellular matrix, we characterized the dynamics and regulation of the regeneration of actinotrichia, which are fin-specific skeletal structures. Our fate mapping experiments demonstrated that the activated mesenchyme of the stump gives rise to the blastema. We are currently investigating which adhesion mechanisms organize the different cells types during fin regeneration.

  • Research profile and curriculum vitae

    The lab of Anna Jazwinska investigates the biological processes of organ regeneration in zebrafish. Her lab established the cryoinjury model system for inducing myocardial infarction in adult fish. Her research identified the preconditioning phenomenon in the zebrafish heart. The focus of her studies includes the coordination of wound repair and functional regeneration of tissues in fish. Her work combines cell and molecular biology, genetics, microscopy, imaging and statistics. Ultimate goal is an improved understanding of the cellular plasticity of mature functional organs in vertebrates.


    Curriculum Vitae


    Nationality:    Swiss and Polish


    1990 – 1995     Study of biology at the University of Warsaw, Poland

    1995 – 1996     Study of biology at the King’s College London England

    June 1996         Master’s degree in biology at the University of Warsaw, Poland


    1996 – 2000     work for PhD in the lab of Prof. Siegried Roth at the Max-Planck Institut für Entwicklungsbiologie in Tübingen, Germany

    June, 2000        PhD degree in developmental biology at the University of Cologne, Germany

     “The role of brinker during embryogenesis and patterning of imaginal discs in Drosophila”

    2000 – 2003     Postdoctoral fellow in the lab of Markus Affolter at the Biozentrum of the University Basel, Switzerland

    2004 – 2005     Postdoctoral fellow in Mark T. Keating’s lab at Children’s Hospital Boston, Harvard Medical School, Boston, USA

    2005 – 2007     Instructor at the Department of Pediatrics, Harvard Medical School and Associate Researcherat the Department of Cardiology, Children’s Hospital Boston, USA

    2008 – 2010     Lecturer at the Department of Medicine, University of Fribourg, Switzerland

    Since 08/2010  Associate Professor at the Department of Biology at the University of Fribourg

    Organizational activities:

    2017 – 2021      Chair of the Swiss Stem Cell Network, organization of the SSCN website

    2019 – 2022      Scientific Delegate of Switzerland to the council of European Molecular Biology Organization (EMBO)

    2019 – 2022      Scientific Delegate of Switzerland to the council of European Molecular Biology Laboratory (EMBL)

    Since 2019       Representative of the University of Fribourg in the Strategic Board of the Swss Animal Facilities Network (SAFN)



Department of Biology

Chemin du Musée 10 
CH-1700 Fribourg