title: Analogous cellular contribution and healing mechanisms following digit amputation and phalangeal fracture in mice.
abstract: Regeneration of amputated structures is severely limited in humans and mice, with complete regeneration restricted to the distal portion of the terminal phalanx (P3). Here, we investigate the dynamic tissue repair response of the second phalangeal element (P2) post amputation in the adult mouse, and show that the repair response of the amputated bone is similar to the proximal P2 bone fragment in fracture healing. The regeneration-incompetent P2 amputation response is characterized by periosteal endochondral ossification resulting in the deposition of new trabecular bone, corresponding to a significant increase in bone volume; however, this response is not associated with bone lengthening. We show that cells of the periosteum respond to amputation and fracture by contributing both chondrocytes and osteoblasts to the endochondral ossification response. Based on our studies, we suggest that the amputation response represents an attempt at regeneration that ultimately fails due to the lack of a distal organizing influence that is present in fracture healing.
authors: Department of Cell and Molecular Biology Tulane University New Orleans Louisiana 70118 USA; Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine Texas A&M University College Station Texas 77843 USA.
authors: Lindsay A
authors: LA
authors: Dawson
authors: Department of Cell and Molecular Biology Tulane University New Orleans Louisiana 70118 USA; Department of Biology University of Kentucky Lexington Kentucky 40506 USA.
authors: Jennifer
authors: J
authors: Simkin
authors: Department of Cell and Molecular Biology Tulane University New Orleans Louisiana 70118 USA; Department of Orthopedics University of Colorado Denver Aurora Colorado 80010 USA.
authors: Michelle
authors: M
authors: Sauque
authors: Department of Cell and Molecular Biology Tulane University New Orleans Louisiana 70118 USA.
authors: Maegan
authors: M
authors: Pela
authors: Department of Cell and Molecular Biology Tulane University New Orleans Louisiana 70118 USA.
authors: Teresa
authors: T
authors: Palkowski
authors: Department of Cell and Molecular Biology Tulane University New Orleans Louisiana 70118 USA; Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine Texas A&M University College Station Texas 77843 USA.
authors: Ken
authors: K
authors: Muneoka
keywords: Digit; endochondral ossification; fracture; mouse; periosteum; regeneration