Optimizing isolation culture and freezing methods to preserve Wharton's jelly's mesenchymal stem cell (MSC) properties: an MSC banking protocol validation for the Hellenic Cord Blood Bank.

BACKGROUND: Mesenchymal stem or stromal cells (MSCs) are a heterogeneous population that can be isolated from many tissues including umbilical cord Wharton's jelly (UC-WJ). Although initially limited in studies such as a hematopoietic stem cell transplantation adjuvant, an increasing number of clinical trials consider MSCs as a potential anti-inflammatory or a regenerative medicine agent. It has been proposed that creating a repository of MSCs would increase their availability for clinical applications. The aim of this study was to assess the optimal isolation and cryopreservation procedures to facilitate WJ MSC banking. STUDY DESIGN AND METHODS: Cells were isolated from UC-WJ using enzymatic digestion or plastic adhesion methods. Their isolation efficacy, growth kinetics, immunophenotype, and differentiation potential were studied, as well as the effects of freezing. Flow cytometry for common MSC markers was performed on all cases and differentiation was shown with histocytochemical staining. Finally, the isolation efficacy on cryopreserved WJ tissue fragments was tested. RESULTS: MSC isolation was successful using both isolation methods on fresh UC-WJ tissue. However, UC-WJ MSC isolation from frozen tissue fragments was impossible. Flow cytometry analysis revealed that only MSC markers were expressed on the surface of the isolated cells while differentiation assays showed that they were capable of trilinear differentiation. All the above characteristics were also preserved in isolated UC-WJ MSCs over the cryopreservation study period. CONCLUSION: These data showed that viable MSCs can only be isolated from fresh UC-WJ tissue, setting the foundation for clinical-grade banking.

Antagonists of retinoic acid and BMP4 affect fetal mouse osteogenesis and odontoblast differentiation.

Retinoic acid and bone morphogenetic protein (BMP4) are endogenous factors indispensable for the physiological development of vertebrates. The proximate aim of the present study was to investigate whether the natural compound citral (a retinoic acid synthesis inhibitor) and a monoclonal, anti-BMP4 antibody, administered to pregnant mice affect in the fetuses cranial osteogenesis and odontoblast differentiation. The present investigation was motivated by the fact that, retinoic acid inhibitors and BMP4 neutralizers may frequently contact human tissues (both intentional and unintentional, and/or unconsciously) inducing unanticipated effects. Our ultimate goal is the prevention of side effects and, future clinical implementation of the results. To this end, pregnant, white mice (balb-c Mus musculus) were intra-abdominally injected with either citral or anti-BMP4 antibody at the 9th gestational day. Newborns were processed within 5h, postnatal. Results were evaluated (a) macroscopically, (b) stereoscopically, following histochemical double staining of cartilage and osseous tissues and, (c) microscopically after (c(1)) histological staining of paraffin sections, and, (c(2)) immunohistochemical detection of apoptosis. Data indicate that in vivo administration of citral (biomimicking hypovitaminosis A) caused restriction/retardation of cranial chondrogenesis and osteogenesis. Apoptosis was not detected in teeth tissues. In vivo administration of anti-BMP4 antibody resulted in a transitory interference with the normal course of odontoblast differentiation and the production of pre-dentin, whereas, delay in the ossification also included the alveoli. Animals inspected in adulthood displayed a fairly normal phenotype. It is concluded that those two substances, under their concentrations experienced, are quite safe for the public.

Cranial and postcranial skeletal variations induced in mouse embryos by mobile phone radiation.

This study focuses on foetal development following mild daily exposure of pregnant mice to near field electromagnetic radiation emitted by a mobile phone. The investigation was motivated by the fact that the potentially hazardous electromagnetic radiation emitted by mobile phones is currently of tremendous public interest. Physically comparable pregnant mice were exposed to radiofrequency radiation GSM 900MHz emitted by a mobile phone. Within 5h after birth most cubs were fixed followed by double staining in toto, and conventional paraffin histology. Other cubs remained with their mothers until teeth eruption. Structural development was assessed by examining newborns for the presence of anomalies and/or variations in soft tissues and skeletal anatomy. Electromagnetic radiofrequency exposed newborns, externally examined, displayed a normal phenotype. Histochemical and histological studies, however, revealed variations in the exposed foetuses with respect to control ones concerning the ossification of cranial bones and thoracic cage ribs, as well as displacement of Meckelian cartilage. Littermates examined after teeth eruption displayed normal phenotypes. It is concluded that mild exposure to mobile phone radiation may affect, although transiently, mouse foetal development at the ossification level. The developmental variations observed could be explained by considering the different embryonic origin and mode of ossification of the affected skeletal elements.

A curriculum vitae of teeth: evolution, generation, regeneration.

The ancestor of recent vertebrate teeth was a tooth-like structure on the outer body surface of jawless fishes. Over the course of 500,000,000 years of evolution, many of those structures migrated into the mouth cavity. In addition, the total number of teeth per dentition generally decreased and teeth morphological complexity increased. Teeth form mainly on the jaws within the mouth cavity through mutual, delicate interactions between dental epithelium and oral ectomesenchyme. These interactions involve spatially restricted expression of several, teeth-related genes and the secretion of various transcription and signaling factors. Congenital disturbances in tooth formation, acquired dental diseases and odontogenic tumors affect millions of people and rank human oral pathology as the second most frequent clinical problem. On the basis of substantial experimental evidence and advances in bioengineering, many scientists strongly believe that a deep knowledge of the evolutionary relationships and the cellular and molecular mechanisms regulating the morphogenesis of a given tooth in its natural position, in vivo, will be useful in the near future to prevent and treat teeth pathologies and malformations and for in vitro and in vivo teeth tissue regeneration.