MONDAY, Sept. 19 (HealthDay News) -- Lineage-restricted, tissue-resident stem cells are involved in the regeneration of the distal digits in mice, according to an experimental study published online Aug. 25 in Nature.
Yuval Rinkevich, Ph.D., from the Stanford University School of Medicine in California, and colleagues investigated the different tissues involved in the regeneration of the mouse digit-tip and whether these cells are derived from pluripotent blastema or lineage-restricted stem cells. The contributions of the ectoderm and mesoderm, and hematopoietic stem cells (HSCs) were analyzed using genetic fate mapping and lineage tracing of tissues of transgenic mice whose digits were amputated and then allowed to heal without suturing for two to three months.
The investigators found that germ-layer restriction is maintained by classes of ectodermal stem cells during digit-tip regeneration, and that ectoderm is further restricted into dorsal and ventral fates and contributions to the nail plate. Analysis of the contribution of mesoderm identified green fluorescent protein-expression in mesodermal tissues in bone tendons, nail bed, dermis, and mesenchyme. Throughout regeneration of the distal digits, germ-layer restriction of mesoderm and ectoderm was maintained by the respective stem and progenitor cells. HSC-derived and other circulating cells did not contribute to the major tissues of the digit.
"Tissue stem cells rather than pluripotent blastema cells are an evolutionarily conserved cellular mode for limb regeneration after amputation," the authors write.
Abstract
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