The Impact of Various Culture Conditions on Human Mesenchymal Stromal Cells Metabolism

In vitro and in vivo analyses are closely connected, and the reciprocal relationship between the two comprises a key assumption with concern to the conducting of meaningful research. The primary purpose of in vitro analysis is to provide a solid background for in vivo and clinical study purposes. The fields of cell therapy, tissue engineering, and regenerative medicine depend upon the high quality and appropriate degree of the expansion of mesenchymal stromal cells (MSCs) under low-risk and well-defined conditions. Hence, it is necessary to determine suitable alternatives to fetal bovine serum (FBS—the laboratory gold standard) that comply with all the relevant clinical requirements and that provide the appropriate quantity of high-quality cells while preserving the required properties. Human serum (autologous and allogeneic) and blood platelet lysates and releasates are currently considered to offer promising and relatively well-accessible MSC cultivation alternatives. Our study compared the effect of heat-inactivated FBS on MSC metabolism as compared to its native form (both are used as the standard in laboratory practice) and to potential alternatives with concern to clinical application—human serum (allogeneic and autologous) or platelet releasate (PR-SRGF). The influence of the origin of the serum (fetal versus adult) was also determined. The results revealed the key impact of the heat inactivation of FBS on MSCs and the effectiveness of human sera and platelet releasates with respect to MSC behaviour (metabolic activity, proliferation, morphology, and cytokine production)

Developmental variability channels mouse molar evolution

International audienceDo developmental systems preferentially produce certain types of variation that orient phenotypic evolution along preferred directions? At different scales, from the intra-population to the interspecific, the murine first upper molar shows repeated anterior elongation. Using a novel quantitative approach to compare the development of two mouse strains with short or long molars, we identified temporal, spatial and functional differences in tooth signaling center activity, that arise from differential tuning of the activation-inhibition mechanisms underlying tooth patterning. By tracing their fate, we could explain why only the upper first molar reacts via elongation of its anterior part. Despite a lack of genetic variation, individuals of the elongated strain varied in tooth length and the temporal dynamics of their signaling centers, highlighting the intrinsic instability of the upper molar developmental system. Collectively, these results reveal the variational properties of murine molar development that drive morphological evolution along a line of least resistance

One Odontogenic Cell-Population Contributes to the Development of the Mouse Incisors and of the Oral Vestibule

<div><p>The area of the oral vestibule is often a place where pathologies appear (e.g., peripheral odontomas). The origin of these pathologies is not fully understood. In the present study, we traced a cell population expressing Sonic hedgehog (<i>Shh</i>) from the beginning of tooth development using Cre-LoxP system in the lower jaw of wild-type (WT) mice. We focused on <i>Shh</i> expression in the area of the early appearing rudimentary incisor germs located anteriorly to the prospective incisors. The localization of the labelled cells in the incisor germs and also in the inner epithelial layer of the vestibular anlage showed that the first very early developmental events in the lower incisor area are common to the <i>vestibulum oris</i> and the prospective incisor primordia in mice. Scanning electron microscopic analysis of human historical tooth-like structures found in the vestibular area of jaws confirmed their relation to teeth and thus the capability of the vestibular tissue to form teeth. The location of labelled cells descendant of the early appearing <i>Shh</i> expression domain related to the rudimentary incisor anlage not only in the rudimentary and functional incisor germs but also in the externally located anlage of the oral vestibule documented the odontogenic potential of the vestibular epithelium. This potential can be awakened under pathological conditions and become a source of pathologies in the vestibular area.</p></div

Tooth-like structures in a historical skull confirm the odontogenic potential of the vestibular epithelium.

<p>During rescue archaeological research in 2007 and 2008 at the Gan locality (Galanta district, Slovak Republic, the Migration Period, 5th - 6th c. AD), three tooth-like structures were found in a female skull excavated from grave AH19 (<b>A-F</b>). Two tooth-like structures were located in the mandible (<b>A-B</b>) externally to the alveoli (a), one on the surface of the mandibular bone (orange arrowhead, <b>A, C, E</b>) and one within the mandibular bone (black arrowhead, <b>B</b>). One dental particle was found free among the bone fragments (blue arrowhead, <b>C, D, F</b>). Scanning electron microscopy (<b>D-F</b>) showed aprismatic (Ap) and prismatic enamel (p) with tubercles (t) and fossae (f) or grooves (g) formation on the surface of the scanned denticles. Openings (o) presumably for vessels or nerves were detected.</p

Oral vestibule in the mouse.

<p>In the mouse lower jaw (<b>A</b>), the anterior lower oral vestibule (VO) is a free space of oral cavity bounded externally (labial) by the mucosa of the lips and orally by the alveolar mucosa, gingiva, and teeth (<b>B, C</b>). It originates as a vestibular lamina (VE) adjacent to the dental epithelium (DE), which is a developmental base of functional incisors (FI) comprising epithelial (yellow) and mesenchymal (orange) material. Vestibular lamina itself gives rise to the epithelial lining of the oral vestibule space in an adult mouse lower jaw.</p

Table of the used material—Cre-loxP system Nr.2.

<p>Numbers of harvested embryos (obtained using the tamoxifen inducible Cre-loxP system Nr.2: LacZ x B6.129S6-Shh/J) 24/48/72/96 and 120 hours (h) after tamoxifen injection at embryonic day (E)11.5 positive for X-gal staining.</p

Table of the used material—Cre-loxP system Nr.1.

<p>Numbers of harvested embryos (obtained using the Cre-loxP system Nr.1: LacZ x B6.Cg-<i>Shh</i>^tm1(EGFP/cre)Cjt/J) positive for X-gal staining.</p