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Pluripotent stem cells offer unprecedented potential not only for human medicine but also for veterinary medicine, particularly in relation to the horse. Induced pluripotent stem cells (iPSCs) are particularly promising, as they are functionally similar to embryonic stem cells and can be generated in vitro in a patient-specific manner. In this study, we report the generation of equine iPSCs from skin fibroblasts obtained from a foal and reprogrammed using viral vectors coding for murine Oct4, Sox2, c-Myc, and Klf4 sequences. The reprogrammed cell lines were morphologically similar to iPSCs reported from other species and could be stably maintained over more than 30 passages. Immunostaining and polymerase chain reaction analyses revealed that these cell lines expressed an array of endogenous markers associated with pluripotency, including OCT4, SOX2, NANOG, REX1, LIN28, SSEA1, SSEA4, and TRA1-60. Furthermore, under the appropriate conditions, the equine iPSCs readily formed embryoid bodies and differentiated in vitro into cells expressing markers of ectoderm, mesoderm, and endoderm, and when injected into immunodeficient mice, gave raise to tumors containing differentiated derivatives of the 3 germ layers. Finally, we also reprogrammed fibroblasts from a 2-year-old horse. The reprogrammed cells were similar to iPSCs derived from neonatal fibroblasts in terms of morphology, expression of pluripotency markers, and differentiation ability. The generation of these novel cell lines constitutes an important step toward the understanding of pluripotency in the horse, and paves the way for iPSC technology to potentially become a powerful research and clinical tool in veterinary biomedicine.

Basaltic lavas from Grenada, Lesser Antilles, may be divided into two series on the basis of CaO-MgO relations. The C-series roughly corresponds to the ankaramites or high-Sr series of the earlier literature and may be distinguished from the M-series basalts by higher CaO at a given MgO and by their strongly augite-phyric nature. Compositional variation within the C-series is dominated by fractional crystallization of augite and plagioclase but this was accompanied by assimilation of sedimentary material from the island arc crust. The assimilation-fractional crystallization process is well illustrated by an increase in 206 Pb/ 204 Pb from 18.6 to 19.4 with fractionation, and correlated increases in Nd/Sr, Zr/Sm and Rb/Ba. The most primitive members of the C-series can not be generated from erupted M-series near-primary basalts, but instead show evidence for an origin by olivine fractionation from high-Mg basalts never seen at the surface. These appear to have been derived from a source similar to that of MORB, but enriched in 87 Sr and other hydrophile elements by dehydration of subducted lithosphere, and in REE and radiogenic Pb by a small component of subducted sediment.

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