title: Wound repair during arm regeneration in the red starfish Echinaster sepositus.
abstract: Starfish can regenerate entire arms following their loss by both autotomic and traumatic amputation. Although the overall regenerative process has been studied several times in different asteroid species, there is still a considerable gap of knowledge as far as the detailed aspects of the repair phase at tissue and cellular level are concerned, particularly in post-traumatic regeneration. The present work is focused on the arm regeneration model in the Mediterranean red starfish Echinaster sepositus; to describe the early cellular mechanisms of arm regeneration following traumatic amputation, different microscopy techniques were employed. In E. sepositus, the repair phase was characterized by prompt wound healing by a syncytial network of phagocytes and re-epithelialisation followed by a localized subepidermal oedematous area formation. Scattered and apparently undifferentiated cells, intermixed with numerous phagocytes, were frequently found in the wound area during these first stages of regeneration and extensive dedifferentiation phenomena were seen at the level of the stump, particularly in the muscle bundles. A true localized blastema did not form. Our results confirm that regeneration in asteroids mainly relies on morphallactic processes, consisting in extensive rearrangement of the existing tissues which contribute to the new tissues through cell dedifferentiation, redifferentiation, and/or migration.
authors.affiliation: Laboratory of Genetics, Biodiversity and Valorization of Bioresources, Higher Institute of Biotechnology, University of Monastir, Monastir, Tunisia.
authors.forename: Yousra
authors.initials: Y
authors.lastname: Ben Khadra
authors.affiliation: Department of Biosciences, University of Milan, Milan, Italy.
authors.forename: Cinzia
authors.initials: C
authors.lastname: Ferrario
authors.affiliation: Department of Biosciences, University of Milan, Milan, Italy.|King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences and Engineering Division, Thuwal, Saudi Arabia.
authors.forename: Cristiano
authors.initials: C
authors.lastname: Di Benedetto
authors.affiliation: Laboratory of Genetics, Biodiversity and Valorization of Bioresources, Higher Institute of Biotechnology, University of Monastir, Monastir, Tunisia.
authors.forename: Khaled
authors.initials: K
authors.lastname: Said
authors.affiliation: Department of Biosciences, University of Milan, Milan, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Bonasoro
authors.affiliation: Department of Biosciences, University of Milan, Milan, Italy.
authors.forename: M Daniela Candia
authors.initials: MD
authors.lastname: Carnevali
authors.affiliation: Department of Biosciences, University of Milan, Milan, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Sugni
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004817:Epidermis / Q000293:injuries / Q000648:ultrastructure*; D017348:Microscopy, Electron, Scanning Transmission; D062326:Re-Epithelialization / Q000502:physiology*; D013215:Starfish; D014945:Wound Healing / Q000502:physiology*; D014947:Wounds and Injuries / Q000473:pathology*
keywords: Echinaster sepositus; arm regeneration; morphallaxis; repair phase; subepidermal oedematous area; wound healing