Restoration versus reconstruction: cellular mechanisms of skin, nerve and muscle regeneration compared

Regenerative Medicine Research

卷:1

关键词: Damage;    Necrosis;    Regeneration;    Differentiation;    Epithelial tissue;    Nervous tissue;    Skeletal muscle tissue;    Skin scar;    Stem cells;    Extra cellular matrix;   

DOI  :  10.1186/2050-490X-1-4

来源: DOAJ

【 摘 要 】

In tissues characterized by a high turnover or following acute injury, regeneration replaces damaged cells and isinvolved in adaptation to external cues, leading to homeostasis of many tissues during adult life. An understandingof the mechanics underlying tissue regeneration is highly relevant to regenerative medicine-based interventions. Inorder to investigate the existence a leitmotif of tissue regeneration, we compared the cellular aspects ofregeneration of skin, nerve and skeletal muscle, three organs characterized by different types of anatomical andfunctional organization. Epidermis is a stratified squamous epithelium that migrates from the edge of the woundon the underlying dermis to rebuild lost tissue. Peripheral neurons are elongated cells whose neurites are organizedin bundles, within an endoneurium of connective tissue; they either die upon injury or undergo remodeling andaxon regrowth. Skeletal muscle is characterized by elongated syncytial cells, i.e. muscle fibers, that can temporarilysurvive in broken pieces; satellite cells residing along the fibers form new fibers, which ultimately fuse with the oldones as well as with each other to restore the previous organization. Satellite cell asymmetrical division grants areservoir of undifferentiated cells, while other stem cell populations of muscle and non-muscle origin participate inmuscle renewal. Following damage, all the tissues analyzed here go through three phases: inflammation,regeneration and maturation. Another common feature is the occurrence of cellular de-differentiation and/ordifferentiation events, including gene transcription, which are typical of embryonic development. Nonetheless,various strategies are used by different tissues to replace their lost parts. The epidermis regenerates ex novo,whereas neurons restore their missing parts; muscle fibers use a mixed strategy, based on the regrowth of missingparts through reconstruction by means of newborn fibers. The choice of either strategy is influenced by theanatomical, physical and chemical features of the cells as well as by the extracellular matrix typical of a given tissue,which points to the existence of differential, evolutionary-based mechanisms for specific tissue regeneration. Theshared, ordered sequence of steps that characterize the regeneration processes examined suggests it may bepossible to model this extremely important phenomenon to reproduce multicellular organisms.

【 授权许可】

Unknown