XB-ART-41352Int J Dev Biol January 1, 2010; 54 (5): 851-6.
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Cardiomyocytes have been induced from various pluripotent cells, such as embryonic stem cells and myeloid stem cells; however, the generation of cardiac tissues beyond two-dimensional cell-sheets has not been reported. Creating higher order, three-dimensional structures that are unique to heart is the long-awaited next step in realizing cardiac regenerative medicine. We have previously shown that cardiomyocytes can be induced in vitro from undifferentiated cells (animal caps) excised from Xenopus embryos. Cardiomyocytes were induced by first dissociating the animal caps and then reaggregating them following treatment with activin. Here, we describe an interesting method for creating a complete ectopic heart in vivo, involving the introduction of in vitro-created tissue during early embryogenesis. Thus, animal cap reaggregates were transplanted into the abdomen of late-neurula-stage embryos, resulting in two-chambered hearts being formed. The dual-heart larvae matured into adult animals with transplanted hearts intact. Involvement of transplanted hearts in systemic circulation was demonstrated. Moreover, the ectopic hearts possessed higher order structures such as atrium and ventricle, and were morphologically, histologically, and electrophysiologically identical to original hearts. This system should facilitate the study of heart organogenesis and may promote a shift from tissue to organ engineering for clinical applications.
PubMed ID: 20336605
Article link: Int J Dev Biol
Species referenced: Xenopus laevis
Genes referenced: nppa tbx2
Antibodies: Nppa Ab1
Article Images: [+] show captions
|Fig. 4. Electron microscopy and immunohistochemical observations of the heart chambers. (A,D) Electron micrographs of ventricular myocardium in the normal and ectopic hearts. Ectopic hearts showed similar structures to those observed in normal hearts. No ANP granules are apparent in either image. (B,E) Electron micrographs of atrial myocardium in the normal and ectopic hearts. Numerous ANP granules (arrows) are present in both. (C,F) Immunostaining of normal and ectopic hearts with anti-ANP antibody showed strong ANP expression in the atrium (a) and atrium-like region (a, but not in the ventricle (v) or ventricle-like region (v. Scale bars are 1 μm in (A,B,D and E); 200 μm in (C,F).|
|nppa( natriuretic peptide a ) gene expression in sections of hearts from 1 year-old Xenopus laevis adults, as assayed by immunohistochemistry. Key :a: atrium, v: ventricle|