Researchers have successfully regenerated skeletal and connective tissue \u2014 even if not perfectly formed \u2014 demonstrating the next, critical step in limb regeneration.<\/p>\n
For centuries, the inability to regrow lost body parts has been considered a defining limitation of humans and other mammals. While animals like salamanders can regenerate entire limbs, humans are left with scar tissue.<\/p>\n
But\u00a0new research<\/a>\u00a0from the\u00a0Texas A&M College of Veterinary Medicine and Biomedical Sciences (VMBS)<\/a>\u00a0suggests that this limitation may not be permanent. Instead, the capacity for regeneration may still exist \u2014 hidden within the body\u2019s normal healing process.<\/p>\n \u201cWhy some animals can regenerate and others, particularly humans, can\u2019t is a big question that has been asked since Aristotle,\u201d said\u00a0Dr. Ken Muneoka<\/a>, a professor in the VMBS\u2019\u00a0Department of Veterinary Physiology & Pharmacology (VTPP).<\/a>\u00a0\u201cI\u2019ve spent my career trying to understand that.\u201d<\/p>\n In their study, published in\u00a0Nature Communications, Muneoka and his colleagues detail a newly developed two-step treatment that led to the regeneration of bone, joint structures and ligaments. While the results were imperfect, the team believes this approach could be used more immediately to reduce scarring and improve tissues repair after amputations.<\/p>\n In mammals, injuries typically trigger fibrosis, a process in which fibroblast cells rapidly close the wound and form scar tissue. This response prioritizes survival by sealing the injury quickly, but also limits the body\u2019s ability to rebuild missing structures.<\/p>\n In regenerative species, like salamanders that can regrow lost limbs, those same types of cells organize into a blastema, a temporary structure that enables tissue regrowth.<\/p>\n \u201cIt\u2019s as if these cells can move in two different directions,\u201d Muneoka said. \u201cThey could either make a scar or make a blastema. Our research focused on redirecting the behavior of fibroblasts already present at the injury site.\u201d<\/p>\n To test whether mammalian healing could be shifted toward regeneration, researchers developed a sequential treatment using two well-studied growth factors.<\/p>\n The first step involved applying fibroblast growth factor 2 (FGF2) after a wound had already closed. This timing allowed the body to complete its typical healing response, and then the team \u201cchanged what happens next,\u201d Muneoka said.<\/p>\n FGF2 stimulated the formation of a blastema-like structure \u2014 something that does not normally occur in mammals following this type of injury; several days later, a second treatment \u2014 using bone morphogenetic protein 2 (BMP2) \u2014 was applied, triggering those cells to begin forming new structures.<\/p>\n \u201cThis is really a two-step process,\u201d Muneoka said. \u201cYou first shift the cells away from scarring, and then you provide the signals that tell them what to build.\u201d<\/p>\nRedirecting the body\u2019s natural response<\/h2>\n