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Adult human dental pulp stem cells differentiate toward functionally active neurons under appropriate environmental cues

The definitive version may be found at www.wiley.comHuman adult dental pulp stem cells (DPSCs) reside within the perivascular niche of dental pulp and are thought to originate from migrating cranial neural crest (CNC) cells. During embryonic development, CNC cells differentiate into a wide variety of cell types, including neurons of the peripheral nervous system. Previously, we have demonstrated that DPSCs derived from adult human third molar teeth differentiate into cell types reminiscent of CNC embryonic ontology. We hypothesized that DPSCs exposed to the appropriate environmental cues would differentiate into functionally active neurons. The data demonstrated that ex vivo-expanded human adult DPSCs responded to neuronal inductive conditions both in vitro and in vivo. Human adult DPSCs, but not human foreskin fibroblasts (HFFs), acquired a neuronal morphology, and expressed neuronal-specific markers at both the gene and protein levels. Culture-expanded DPSCs also exhibited the capacity to produce a sodium current consistent with functional neuronal cells when exposed to neuronal inductive media. Furthermore, the response of human DPSCs and HFFs to endogenous neuronal environmental cues was determined in vivo using an avian xenotransplantation assay. DPSCs expressed neuronal markers and acquired a neuronal morphology following transplantation into the mesencephalon of embryonic day-2 chicken embryo, whereas HFFs maintained a thin spindle fibroblastic morphology. We propose that adult human DPSCs provide a readily accessible source of exogenous stem/precursor cells that have the potential for use in cell-therapeutic paradigms to treat neurological disease.Agnes Arthur, Grigori Rychkov, Songtao Shi, Simon Andrea Koblar, Stan Grontho

Future dentistry: cell therapy meets tooth and periodontal repair and regeneration

Cell-based tissue repair of the tooth and - tooth-supporting - periodontal ligament (PDL) is a new attractive approach that complements traditional restorative or surgical techniques for replacement of injured or pathologically damaged tissues. In such therapeutic approaches, stem cells and/or progenitor cells are manipulated in vitro and administered to patients as living and dynamic biological agents. In this review, we discuss the clonogenic potential of human dental and periodontal tissues such as the dental pulp and the PDL and their potential for tooth and periodontal repair and/or regeneration. We propose novel therapeutic approaches using stem cells or progenitor cells, which are targeted to regenerate the lost dental or periodontal tissue

Hominins do not share a common postnatal facial ontogenetic shape trajectory

This paper examines the hypothesis raised by recent studies that postnatal trajectories of shape change in the facial skeleton are parallel between, at least, chimpanzees, modern humans and also fossil hominins, specifically australopithecines and possibly Neanderthals. In contrast, other studies point to divergences in postnatal shape trajectories within diverse groups of primates. As such there is some debate regarding the relative contributions of pre and postnatal ontogeny to adult morphological differences. This paper presents a series of geometric morphometric studies of the ontogeny of facial shape in hominins with the specific aim of resolving these issues. The results indicate that many differences in facial shape between hominins are established prenatally, however highly significant divergences of postnatal facial ontogeny are found among living hominins. Our studies point to possible differences between the shape ontogeny of the Australopithecus africanus face and that of African apes on the one hand and humans on the other. However, sampling experiments indicate that the small sample size of available specimens of A. africanus does not permit any conclusions to be drawn regarding comparative shape ontogeny of the face