Limb Development

Skeletal development, bone remodeling, and hematopoiesis

“…This triggers active osteoblastogenesis from mesenchymal progenitors, whose origin has not been completely defined. The newly generated osteoblasts differentiate into osteocytes and produce a bone‐specific extracellular matrix using the degraded cartilage matrix as scaffold (38, 39). This initial stage in the formation of bone is the first coordinated developmental process in which bone‐forming and hematopoietic cells interact actively, and disruption by any of the parts is deleterious for survival.…”

Caspase‐3 mediates retinoid‐induced apoptosis in the organogenesis‐stage mouse limb

“…As organogenesis proceeds, paracrine and autocrine messages shuttle between the embryonic cell layers and the regions that start to define themselves by differential protein expression. Many of these areas, such as the apical ectodermal ridge (AER), the interdigital ectoderm, and the polarizing region are the source of crucial signals that support limb patterning and outgrowth and provide positional cues ensuring that structures form with an appropriate cell and tissue organization (for review, see Francis‐West and Tickle, 1996). In the limb bud, retinoids are emerging as key pieces of this network, and have been implicated in the control of patterning and differentiation and in the regulation of apoptosis.…”

“…In the mouse, these areas begin to become apparent about gestation day 10.5 during organogenesis and peak at gestation day 14.5 (Zakeri and Ahuja, 1997). The precise spatiotemporal control of both the extent and the localization of apoptosis during development is critical for normal morphogenesis (for review, see Francis‐West and Tickle, 1996).…”

Aspectos celulares, teciduais e moleculares da osteogênese ectópica e ortotópica induzida pela matriz alogênica óssea e dentinária

“…A importância do VEGF é salientada pela possibilidade de vários fatores de crescimento e de transformação, além de, hormônios, e da própria hipóxia poderem induzir a produção de VEGF por vários tipos celular. culminando com a produção da matriz óssea e medular (FRANCIS- WEST P;TICKLE, 1996;OLSEN;. Por outro lado, o contato osteoclastos-osteoblastos, a comunicação intercelular e a coordenação são cruciais para o controle da diferenciação, ativação e função de ambas as linhagens, tanto no desenvolvimento, quanto no reparo ósseo, mantendo a massa óssea e preservando a estrutura óssea durante a vida do indivíduo (ROODMAN, 1996);SUDA et al, 1997;MANOLAGAS;Jika, 1995).…”