Question

Rntroduction of reprogrammed cells necessary, rather than directly injecting retroviruses carrying tegarding induced pluripotent stem cells (iPSCs), why are steps involving the removal and re-iranscription factors into the target area in vivo?

A) In vivo conditions lack suitable culture environments for reprogramming or differentiation, hindering successful iPSC generation.
B) Retroviruses injected directly into the target area may face immune responses or insufficient delivery, leading to ineffective reprogramming.
C) Variation in the timing of cell transfection and surrounding cellular environments can cause immediate differentiation, limiting iPSC formation.
D) The understanding of reprogrammed cell behavior suggests that all iPSCs form from a blastocyst, not directly from retroviral transfection in vivo.

Answer 1

The steps involving removal and reprogramming of cells for iPSCs are crucial due to the lack of suitable in vivo environments for reprogramming, potential immune responses, risks of non-specific cell targeting, and the necessity of a controlled environment to ensure proper reprogramming and minimize health risks.

Step-by-step explanation:

Regarding induced pluripotent stem cells (iPSCs), the necessity of steps involving the removal and reprogramming of cells, rather than directly injecting retroviruses carrying transcription factors into the target area in vivo, stems from several considerations. In vivo conditions, for one, lack suitable environments for cell reprogramming and differentiation, which are necessary for the successful generation of iPSCs. Direct injection of retroviruses can lead to immune responses or insufficient delivery, both of which hinder effective reprogramming.

Additionally, the direct in vivo application of retroviruses can pose significant risks. The interaction with the immune system can induce an inflammatory response, potentially leading to organ failure. Retroviruses also have the potential for non-specific cell targeting, which could harm cells not intended for therapy, with the possibility of leading to illnesses such as cancer. There is also a risk that the retrovirus could revert to an infectious state or cause the inactivation of other essential genes in the patient's genome, potentially causing tumor formation.

To circumvent these issues, ex vivo gene therapy approaches are used where somatic cells are collected, reprogrammed in culture, and then injected back into the patient. This controlled environment for cell reprogramming allows for screening and selecting properly reprogrammed cells and minimizes the risks mentioned earlier. Moreover, these reprogrammed cells are more likely to be accepted by the patient's body without triggering an immune response, especially when customized to each patient.