pluripotenten

Pluripotenten refers to cells that have the ability to differentiate into cell types derived from all three primary germ layers (ectoderm, mesoderm, and endoderm). Pluripotent cells can give rise to nearly any cell type in the body, but they cannot form extraembryonic tissues such as the placenta.

In mammals, pluripotent cells occur naturally during early development in the inner cell mass of the blastocyst. The most widely studied pluripotent cells are embryonic stem cells (ESCs), derived from that inner cell mass, and induced pluripotent stem cells (iPSCs), which are adult cells reprogrammed to a pluripotent state by transcription factors (originally Oct4, Sox2, Klf4, and c-Myc).

Pluripotency is assessed by the ability to differentiate into derivatives of the three germ layers in vitro, often demonstrated by directed differentiation or the formation of embryoid bodies; in vivo, teratoma formation in immunodeficient animals is used as a demonstration. Markers such as Oct4, Nanog, Sox2, and surface antigens like SSEA-3/4 or Tra-1-60 are commonly evaluated to confirm a pluripotent state.

Applications and challenges: Research uses include disease modeling, drug screening, and potential regenerative therapies. Translating pluripotent cells to clinical use faces obstacles such as genomic instability, risk of tumorigenicity, and immune compatibility, as well as ethical considerations around embryo use. Induced pluripotent stem cells offer routes that alleviate some ethical concerns but introduce issues related to reprogramming signatures and genetic alterations.