Current protocols in the generation of pluripotent stem cells: theoretical, methodological and clinical considerations

Abstract

Pluripotent stem cells have been derived from various embryonic, fetal and adult sources. Embryonic stem cells (ESCs) and parthenogenic ESCs (pESCs) are derived from the embryo proper while embryonic germ cells (EGCs), embryonal carcinoma cells (ECCs), and germ-line stem cells (GSC) are produced from germ cells. ECCs were the first pluripotent stem cell lines established from adult testicular tumors while EGCs are generated in vitro from primordial germ cells (PGCs) isolated in late embryonic development. More recently, studies have also demonstrated the ability to produce GSCs from adult germ cells, known as spermatogonial stem cells. Unlike ECCs, the source of GSCs are normal, non-cancerous adult tissue. The study of these unique cell lines has provided information that has led to the ability to reprogram somatic cells into an ESC-like state. These cells, called induced pluripotent stem cells (iPSCs), have been derived from a number of human fetal and adult origins. With the promises pluripotent stem cells bring to cell-based therapies there remain several considerations that need to be carefully studied prior to their clinical use. Many of these issues involve understanding key factors regulating their generation, including those which define pluripotency. In this regard, the following article discusses critical aspects of pluripotent stem cell derivation and current issues about their therapeutic potential.

Coronary Artery Diseases

“…High alkaline phosphatase and telomerase activity, rapid proliferation, lack of contact inhibition and high nucleus to cytoplasmic ratio with prominent nuclear growing in flat colonies are also further confirmatory indices of successful iPSC achievement [Kooreman & Wu, 2010]. The major criterion for pluripotency is demonstration of the cell lineage's ability to reconstitute tissue composed of three layers by creating chimeras, tetraploid complementation or teratoma formation tests [Swelstad & Kerr, 2009]. Teratoma assay in immunodeficient SCID mice is currently used to test pluripotency in vivo for human iPSCs [Tan et al, 2008].…”

“…iPSCs are characterized by the expression of the above mentioned transcription factors and cell surface molecules (e.g. SSEA-3/4, Tra-1-60 and Tra-1-81) [Swelstad & Kerr, 2009]. High alkaline phosphatase and telomerase activity, rapid proliferation, lack of contact inhibition and high nucleus to cytoplasmic ratio with prominent nuclear growing in flat colonies are also further confirmatory indices of successful iPSC achievement [Kooreman & Wu, 2010].…”