Isolation and characterization of stem cells from pancreatic islet: pluripotency, differentiation potential and ultrastructural characteristics.

BACKGROUND AIMS: Stem cells (SC) in different locations have individual characteristics. Important questions to be answered include how these specialties are generated, what the mechanism underlying their generation is, and what their biologic and clinical merits are. A basic approach to answering these questions is to make comparisons between the differences and similarities among the various SC types. They may focus on aspects of biologic marker discovery, capacity of proliferation and differentiation, along with other characteristics. The aim of this study was to characterize in detail the SC isolated from pancreatic islet (PI) and compare their properties with bone marrow (BM)-derived mesenchymal stromal cells (MSC) of the rat. METHODS: Immunophenotypic characteristics, proliferation capacities, telomerase activities, pluripotent-related gene expressions, ultrastructure and the potential for multilineage differentiation of PI SC and BM MSC were studied. RESULTS: We found that PI SC expressed markers of embryonic SC (Oct-4, Sox-2 and Rex-1) and had a high proliferation capacity, proven also by high telomerase activities. Surprisingly, markers belonging to differentiated cells were expressed by these cells in a constitutive manner. PI SC ultrastructure showed more developed and metabolically active cells. CONCLUSIONS: The immunocytochemical identification of both PI SC and BM MSC was demonstrated to be typical MSC. Without stimulation of differentiation markers of adipogenic, chondrogenic, neurogenic, myogenic and osteogenic cells in these SC, the expression of those markers might explain their multilineage differentiation potential. We suggest that, by reason of the respectively high telomerase activity in PI SC, they could be better candidates than BM MSC for cell replacement therapy of type 1 diabetes.

Effect of cigarette smoke and alpha-tocopherol (vitamin E) on fertilization, cleavage, and embryo development rates in mice: an experimental in vitro fertilization mice model study.

OBJECTIVE: The objective was to elucidate the effects of cigarette smoke per se or vitamin E on mice exposed to cigarette smoke, with regard to fertility and cleavage rates, and embryo development in an experimental in vitro fertilization (IVF) mice model. STUDY DESIGN: Female and male mice, weighing 18-25 g and aged 14-16 weeks, were separated and divided into cigarette smoke-exposed (SE) and non-smoke-exposed (NSE) groups. A specially designed cage with a cigarette smoking machine was constructed. The SE (20 cigarettes/day) group was put in the cage for 10 weeks. SE and NSE female and male mice were given 50mg/kg of vitamin E intraperitoneally for 10 weeks and were cross-mated thereafter so as to produce seven different subgroups of mice population as follows: group I-NSE male and female mice (control); group II-SE female mice and NSE male mice; group III-NSE female with SE male mice; group IV-SE male and SE female mice; group V-SE female mice treated with vitamin E and SE only male mice; group VI-SE only female and male mice treated with vitamin E; and finally group VII-vitamin E-treated SE male and female mice. Following superovulation with FSH, follicles of female mice were obtained via laparotomy under high-dose ether. Male mice testicles were retrieved via the same surgical procedure. Both gametes were obtained and used for IVF. Fertilization, cleavage rates, and day 3 embryo grading were assessed in four groups. RESULTS: With regard to fertilization rate, group II (36%) significantly differed from group I (85%, p=0.002), group III (68.7%, p=0.04), but not from group IV (20.6%, p=0.34). Taking embryo development rate into consideration, group II (32%) had a lower percentage of embryo development compared with group I (75%, p<0.01) and group III (62.5%, p<0.001), but not group IV (17.2%, p=0.42). Percentages of embryo cleavage, embryo development, and day 3 grade I embryos did differ among four of the groups (p>0.05). CONCLUSIONS: Fertilization and cleavage rates were mainly affected in the SE female mice population. The impact of vitamin E on fertilization, cleavage, and embryo development rates was not relevant among SE male and SE female mice.