Regenerative medicine was the term coined by William A. Haseltine in 2000. This tries to heal the body by stimulation of endogenous cells to repair damaged tissues, or transplantation of cells or engineered tissues to replace diseased or injured.
Tissue injuries are normally repaired by formation of fibrous scar tissue in humans. But a number of tissues in mammals including epithelia, bone marrow, and muscle undergo regeneration to keep tissue integrity after cell loss .
Some lower animals can undertake full organ regeneration.Though not entirely clear, two mechanisms play roles in regeneration.
- Stem cells mediation
- Dedifferentiation of lineage specified cells
In the freshwater planarian, pluripotent, stem-like cells called neoblasts distributed throughout the body divide and differentiate into the approximately 40 cell types necessary to regenerate the planarian body from small fragments.
Activation of preexisting stem cells in mammals is responsible for the limited regeneration seen in tissues such as muscle and blood
The extracts of the newt regenerating limb render dedifferentiation of multinucleated mouse myotubes into mononucleated myoblasts in vitro. This suggests that some of the pathways involved in regeneration are conserved. This area of dedifferentiation is being actively pursued. Aparticular strain of mice confers the ability to regenerate, resembling that of amphibians. This raises the hope that humans may also have untapped regeneration capacity.
Stem cell biologists study the molecular pathways involved in self-renewal and lineage-specific differentiation to generate specific cell types required for clinical applications.
About Arun Pal Singh