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Khosravi-Maharlooei M.,Cell science Research Center | Khosravi-Maharlooei M.,University of British Columbia | Hajizadeh-Saffar E.,Cell science Research Center | Tahamtani Y.,Cell science Research Center | And 14 more authors.
European Journal of Endocrinology | Year: 2015

Over the past decades, tremendous efforts have been made to establish pancreatic islet transplantation as a standard therapy for type 1 diabetes. Recent advances in islet transplantation have resulted in steady improvements in the 5-year insulin independence rates for diabetic patients. Here we review the key challenges encountered in the islet transplantation field which include islet source limitation, sub-optimal engraftment of islets, lack of oxygen and blood supply for transplanted islets, and immune rejection of islets. Additionally, we discuss possible solutions for these challenges. © 2015 European Society of Endocrinology. Source

Jafari S.,University Putra Malaysia | Jafari S.,Royan Institute for Animal Biotechnology | Hosseini M.S.,Royan Institute for Animal Biotechnology | Hajian M.,Royan Institute for Animal Biotechnology | And 15 more authors.
Molecular Reproduction and Development | Year: 2011

In this study, fibroblast cells were stably transfected with mouse POU5F1 promoter-driven enhanced green fluorescent protein (EGFP) to investigate the effect of S-adenosylhomocysteine (SAH), the reversible non-toxic inhibitor of DNA-methyltransferases (DNMTs), at different intervals post-fusion on in vitro development of cloned bovine embryos. Treatment with SAH for 12hr resulted in 54.6±7.7% blastocyst production, which was significantly greater than in vitro fertilized embryos (IVF: 37.2±2.7%), cloned embryos treated with SAH for 72hr (31.0±7.6%), and control cloned embryos (34.6±3.6%). The fluorescence intensities of the EGFP-POU5F1 reporter gene at all intervals of SAH treatment, except of 72hr, were significantly higher than control somatic cell nuclear transfers (SCNT) embryos. The intensity of DNA-methylation in cloned embryos treated with SAH for 48hr was similar to that of IVF embryos, and was significantly lower than the other SCNT groups. The levels of H3K9 acetylation in all SCNT groups were significantly lower than IVF embryos. Real-time PCR analysis of gene expression revealed significantly higher expression of POU5F1 in cloned versus IVF blastocysts. Neither embryo production method (SCNT vs. IVF) nor the SAH treatment interval affected expression of the BCL2 gene. Cloned embryos at all intervals of SAH treatment, except for 24hr, had significantly increased VEGF transcript compared to IVF and control SCNT embryos. It was suggested that the time interval of DNMT inhibition may have important consequences on different in vitro features of bovine SCNT, and the improving effects of DNMT inhibition on developmental competency of cloned embryos are restricted to a specific period of time preceding de novo methylation. © 2011 Wiley-Liss, Inc. Source

Hosseini S.O.,Royan Institute for Animal Biotechnology | Aghaee F.,Shahrekord University | Hosseini S.M.,Royan Institute for Animal Biotechnology | Hajian M.,Royan Institute for Animal Biotechnology | And 6 more authors.
Small Ruminant Research | Year: 2011

This study was carried out to evaluate the pattern of reactive oxygen species (ROS) production variation during in vitro oocyte development and maturation and embryonic development in sheep, and to investigate whether embryo culture conditions and the presence of cell-permeable superoxide dismutase mimetic [Manganese (III) meso-tetrakis (4-benzoic acid) porphyrin (MnTBAP)] can influence the ROS production pattern. Oocytes at the germinal vesicle (GV), germinal vesicle breakdown (GVBD) and metaphase II (MII) stages and fertilized embryos at different stages of development (2, 4, 8 and 16-cell, morula, blastocyst and hatching) in two embryo culture media [modified synthetic oviductal fluid (mSOF) or tissue culture medium (TCM199)] were used for assessment of the ROS levels, using a 2,7-dichloro dihydro flourescein diacetate (DCHFDA) probe. A dose of 200 μM MnTBAP was added to the mSOF before, after or before/after embryo arrest (4th embryonic cell cycle) or to the TCM199 media throughout the culture period. ROS levels in immature and unfertilized oocytes were significantly lower, when compared to all fertilized embryonic stages (P<0.05). Maximum ROS levels were detected in the morula stage embryos with TCM199 (77.9 ± 1.7) and for the 16-cell stage embryos in mSOF (75.2 ± 2.6). Blastocyst formation was concomitant with a sharp decrease in the ROS production level. The addition of MnTBAP did not significantly decrease the ROS levels and embryonic development. In conclusion it can be said that (i) fertilization triggers an increase in ROS levels, which peaked around the embryo arrest time window, (ii) embryo culture conditions do not confer significant changes in the ROS production pattern, accompanied by a subtle change in surge time, and (iii) MnTBAP does not affect the ROS levels and embryo yield rate. © 2011 Elsevier B.V. Source

Jafari S.,University Putra Malaysia | Jafari S.,Royan Institute for Animal Biotechnology | Hosseini S.M.,Royan Institute for Animal Biotechnology | Hajian M.,Royan Institute for Animal Biotechnology | And 13 more authors.
Journal of Assisted Reproduction and Genetics | Year: 2011

Purpose: To investigate the effect of epigenetic modification on pattern, time and capacity of transcription activation of POU5F1, the key marker of pluripotency, in cloned bovine embryos. Methods: Bovine fibroblasts were stably transfected with POU5F1 promoter-driven enhanced green fluorescent protein (EGFP). This provided a visible marker to investigate the effect of post-activation treatment of cloned bovine embryos with trichostatin A (TSA) on time and capacity of POU5F1 expression and its subsequent effect on in vitro development of cloned bovine embryos. Results: Irrespective of TSA treatment, POU5F1 expression was not detected until 8-16 cell stage, but was detected in both inner cell mass and trophectoderm at the blastocyst stage. TSA treatment significantly increased POU5F1 expression, and the yield and quality of cloned embryo development compared to control. Conclusion: The POU5F1 expression of cloned embryos is strictly controlled by the stage of embryo development and may not be altered by TSA-mediated changes occur in DNA-methylation and histone-acetylation of the genome. © 2011 Springer Science+Business Media, LLC. Source

Hajian M.,Royan Institute for Animal Biotechnology | Hosseini S.M.,Royan Institute for Animal Biotechnology | Forouzanfar M.,Islamic Azad University at Marvdasht | Abedi P.,Royan Institute for Animal Biotechnology | And 12 more authors.
European Journal of Wildlife Research | Year: 2011

Among the wide range of bio-conservational strategies envisaged, recent accomplishments in the field of interspecies somatic cell nuclear transfer (iSCNT) hold considerable promise due to its unique potential to decelerate or prevent rapid loss of animal genetic resources, and even to revive extinct species. Accordingly, this study was carried out to investigate if in vitro matured and enucleated oocytes of domestic sheep could be used for interspecies conservation cloning of Esfahan mouflon (Ovis orientalis isphahanica), a vulnerable species classified by the International Union for Conservation of Nature. Cryo-banked fibroblasts of a mouflon (derived from a genome resource bank) and a domestic sheep (prepared during a recent study) were cultured in vitro and used for karyotyping. Prior to SCNT, fibroblast donor cells were serum starved for 5 days. Using the zona-free SCNT technique, in vitro matured and enucleated domestic sheep oocytes were reconstituted with nuclei donor cells of mouflon and domestic sheep, and their competencies for in vitro development to the blastocyst stage were compared. The cloned mouflon blastocysts were then surgically transferred into the uterus of the synchronized domestic sheep. Karyotype analysis confirmed that fibroblasts of the Esfahan mouflon had the correct number of diploid chromosomes (2n = 54). Evaluation of 907 activated reconstructs [Esfahan mouflon (n = 667), domestic sheep (n = 240)] revealed no significant difference in the term of blastocyst development (7.6 ± 0.5% vs. 9.3 ± 0.5%, respectively). After the transfer of 12 cloned Esfahan mouflon blastocysts to five domestic sheep recipients, two (40.0%) pregnancies were established in which both (100%) were sustained until caesarean section (days 147 and 150 of pregnancy, respectively) and culminated in the live births of cloned Esfahan mouflon lambs. However, the newborns did not survive and died soon after birth. Karyotype and genetic analyses confirmed that both clones had correct diploid chromosome number (2n = 54), and were genetically identical to each other in addition to their original cell donor. This study highlighted the importance of "conservation cloning" using closely related abundant alternate species. © 2011 Springer-Verlag. Source

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