Context:

• In cases such as bone marrow transplantation, which involves the transplantation of hematopoietic stem cells, namely stem cells that give rise to other types of blood cells, a younger donor age results in a better outcome. A group of Indian scientists have now developed a mechanism that can rejuvenate stem cells from older donors, making them useful for transplantation.
• The mechanism developed by researchers at the National Centre for Cell Science (NCCS), Pune, involves rejuvenating aged hematopoietic stem cells in a short-term culture using micro-vesicles secreted by young stromal cells.

Relevance:

• The finding has relevance in clinical bone-marrow transplantation, wherein aged donors are usually not preferred as their stem cells could have compromised engraftment ability due to ageing.
• With the new mechanism, it might be possible to rejuvenate aged stem cells and thereby expand the donor pool.

Stromal cells:

• Stromal cells are support cells present in the micro-environment of stem cells.
• These cells display activated AkT signalling as they age.
• This leads to a loss of autophagy-inducing mRNAs in their micro-vesicles.
• If this signalling is blocked by using chemical inhibitors in aged stromal cells in culture, they become ‘young-like’ and secrete good quality micro-vesicles containing autophagy-inducing mRNA that can rejuvenate aged stem cells.

Source:TH