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University of Stirling scientists have discovered cells in the skin of Atlantic salmon that offer new insights into how wounds heal, tissues regenerate, and cellular transitions support long-term skin health.

By understanding how skin cells remodel and heal tissue, researchers hope to develop new strategies to enhance tissue integrity and reduce non-healing wounds, potentially improving salmon farming mortality rates.

Research led by Dr. Rose Ruiz Daniels of the University's Institute of Aquaculture uncovered the previously unknown population of stem cells.

Published in BMC Biology, the , "Transcriptomic characterization of transitioning cell types in the skin of Atlantic salmon," reveals that fibroblast-like stem cells—known as mesenchymal stromal cells (MSCs)—play a central role in the remodeling phase of wound healing, which is critical for restoring skin integrity following injury.

Using advanced cell profiling technologies—single-nucleus RNA sequencing and spatial transcriptomics—the researchers profiled skin cells during a wound healing time course.

Dr. Rose Ruiz Daniels said, "We found MSCs at both the wound site and in intact skin, suggesting these adult stem cells are a stable and functional part of salmon skin, and likely to be involved in maintaining its barrier and structural properties.

"These cells become more transcriptionally active during the remodeling stage of healing and show signs of differentiating into multiple tissue types including bone and fat.

"This hints at a broader regenerative capacity in fish skin than previously understood, potentially linking repair processes in the skin to those in deeper tissues like muscle, scales, and connective tissue."

MSC-like cells are well characterized in mammals, but this study suggests that in teleost fish such as salmon, these cells may retain higher pluripotency—or stemness—meaning they can take on a wider range of regenerative roles.

This raises the possibility that fish skin regeneration may operate through more flexible cellular pathways than in terrestrial vertebrates.

The study also maps the spatial niches of various MSC subclusters, laying the groundwork for future studies aimed at manipulating these cells to improve tissue repair, resilience, and overall fish health.

Dr. Ruiz Daniels added, "These findings have potentially far-reaching implications for aquaculture. Barrier tissue health, particularly of the skin and gills, is a major challenge in Atlantic salmon farming and a leading cause of mortality in sea cages.

"There is an urgent need for innovative biotechnological approaches to enhance fish health, as aquaculture also faces mounting challenges from climate change, including heightened disease risks and increased thermal uncertainties.

"By understanding how skin cells remodel and heal tissue, we hope to develop new strategies to enhance tissue integrity and reduce non-healing wounds at barrier tissues."

This study is a collaborative effort across institutions including the University of Stirling, the Roslin Institute, Nofima, and the University of Prince Edward Island.