Stem cells from human exfoliated deciduous tooth exhibit stromal-derived inducing activity and lead to generation of neural crest cells from human embryonic stem cells

The neural crest is a transient structure of early vertebrate embryos that generates neural crest cells [NCCs]. These cells can migrate throughout the body and produce a diverse array of mature tissue types. Due to the ethical and technical problems surrounding the isolation of these early human embryo cells, researchers have focused on in vitro studies to produce NCCs and increase their knowledge of neural crest development. In this experimental study, we cultured human embryonic stem cells [hESCs] on stromal stem cells from human exfoliated deciduous teeth [SHED] for a two-week period. We used different approaches to characterize these differentiated cells as neural precursor cells [NPCs] and NCCs. In the first co-culture week, hESCs appeared as crater-like structures with marginal rosettes. NPCs derived from these structures expressed the early neural crest marker p75 in addition to numerous other genes associated with neural crest induction such as SNAIL, SLUG, PTX3 and SOX9. Flow cytometry analysis showed 70% of the cells were AP2/P75 positive. Moreover, the cells were able to self-renew, sustain multipotent differentiation potential, and readily form neurospheres in suspension culture. SHED, as an adult stem cell with a neural crest origin, has stromal-derived inducing activity [SDIA] and can be used as an NCC inducer from hESCs. These cells provide an invaluable resource to study neural crest differentiation in both normal and disordered human neural crest development

Chromosomal abnormalities in Iranian infertile males who are candidates for assisted reproductive techniques

The present study offers our contribution on the topic by a retrospective analysis of the prevalence of chromosomal abnormalities in a population of Iranian infertile men attending assisted reproduction programs. Cytogenetic analysis was performed according to standard methods on cultured cells obtained from the patient peripheral blood. In all, 874 files belonging to male partner of each couple were classified as follows: azoospermic, oligozoospermic and patients with low sperm quality in respect of morphology and motility. Chromosomal abnormalities were observed in 136[15.5%] individuals of the whole population studied including 12.0%, 1.2% and 2.0% of azoospermic, oligozoospermic and patients with low sperm quality, respectively. Of those, 116 [13.2%] had sex chromosome abnormalities and 20[2.3%] had autosomal chromosome abnormalities. We observed high frequency of aneuploidy and sex chromosomal mosaicism in azoospermic men and high structural aberrations in males with low sperm quality. We suggested that type of chromosomal abnormalities had an inverse relation to sperm count. So that, high chromosomal aneuploidy was detected in males with lower sperm count and high structural aberration was detected in males with low sperm quality. Chromosomal abnormalities are a major cause of male infertility. Consequently, Genetic testing and counselling is indicated for infertile men with abnormal semen parameters with either abnormal karyotype or normal karyotype before applying assisted reproductive techniques