Bone regrowth in young mice stimulated by nail organ

Abstract

Recent studies of postamputational repair following digit-tip amputation revealed an unexpected correlation between nail regrowth and bone regrowth in mice. To examine putative effects of nail on bone regrowth, phalangeal tips were amputated such that nail was artificially removed from distal levels or retained following proximal level amputations. In the absence of nail, bone did not regrow at distal levels. Conversely, when nail was surgically retained bone regrew from proximal levels. The nail organ profoundly influences bone regrowth.

A histomorphologic study of the normal healing response following digit amputation in C57bl/6 and MRL/MpJ mice

“…This study complements a series of studies on mouse digit healing (Schotte and Smith, 1959;Neufeld, 1983Neufeld, , 1985Neufeld, , 1989Zhao, 1993, 1995;Zhao and Neufeld, 1995;Mohammad and Neufeld, 2000;Han et al, 2003;Said et al, 2004;Chadwick et al, 2007;Han et al, 2008) which document the temporal aspects of healing in amputated mouse digits, with the addition of data on stem and progenitor cell infiltration, cell proliferation and angiogenesis. The comparative healing response of two strains of mice are described, specifically the C57bl/6 and MRL/MpJ strains.…”

Digit regeneration is regulated byMsx1andBMP4in fetal mice

“…Regeneration studies on the mature mammalian digit tip have focused almost exclusively on the role of the nail organ and the distal growth of the terminal phalanx (see Zhao and Neufeld, 1995). This association is derived from both clinical studies in humans and experimental studies on rodents (Douglas, 1972;Illingworth, 1974;Borgens, 1982).…”

“…In humans, regenerative potential is restricted to the distal tip of the finger in a region associated with the nail organ (Douglas, 1972;Illingworth, 1974). Experimental studies using rodent models demonstrate that regenerative capacity is level specific and, similarly, is associated with the proximal extent of the nail forming organ (Borgens, 1982;Zhao and Neufeld, 1995). A role for the nail organ in the regeneration response is supported by experiments showing that excluding the nail organ from the amputation wound results in no regenerative response; however, nail organ grafts result in ectopic bone formation and do not induce regeneration (Zhao and Neufeld, 1995;Mohammad et al, 1999).…”

“…Experimental studies using rodent models demonstrate that regenerative capacity is level specific and, similarly, is associated with the proximal extent of the nail forming organ (Borgens, 1982;Zhao and Neufeld, 1995). A role for the nail organ in the regeneration response is supported by experiments showing that excluding the nail organ from the amputation wound results in no regenerative response; however, nail organ grafts result in ectopic bone formation and do not induce regeneration (Zhao and Neufeld, 1995;Mohammad et al, 1999). These experimental results, together with clinical studies in humans, provide evidence that the nail organ plays some role in the stimulation of adult digit tip regeneration.…”

La régénération des appendices chez les vertébrés : un modèle expérimental ancien pour étudier les cellules souches chez l’adulte

“…Chez les oiseaux, la régénération des pattes n'a lieu in ovo que si l'amputation porte sur l'extrémité non différenciée et si la voie FGF (fibroblast growth factor) est stimulée artificiellement; en effet, il semble que la re-formation de la crête ectodermique apicale ou AER (apical epidermal ridge) ne soit pas possible [10,11]. Chez les souriceaux nouveau-nés, il est possible d'observer une régénération de la dernière phalange des doigts [12][13][14]. Chez l'homme, ce phénomène est restreint aux sept premières années et dépend de la présence des cellules souches de l'ongle qui fournissent un ensemble de cellules aptes à proliférer [15] ou -de manière plus générale -stimulent la croissance osseuse [16].…”