Nota promissária: amputados poderão regenerar membros perdidos

quinta-feira, dezembro 17, 2009

How Do Salamanders Grow a New Leg? Protein Mechanisms Behind Limb Regeneration

ScienceDaily (Dec. 15, 2009) — The most comprehensive study to date of the proteins in a species of salamander that can regrow appendages may provide important clues to how similar regeneration could be induced in humans.

Researchers at the School of Science at Indiana University-Purdue University Indianapolis and colleagues investigated over three hundred proteins in the amputated limbs of axolotls, a type of salamander that has the unique natural ability to regenerate appendages from any level of amputation, with the hope that this knowledge will contribute to a better understanding of the mechanisms that allow limbs to regenerate.


A female wild-type axolotl (Ambystoma mexicanum). The most comprehensive study to date of the proteins in a species of salamander that can regrow appendages may provide important clues to how similar regeneration could be induced in humans. (Credit: iStockphoto/Armin Hinterwirth

"In some ways this study of the axoltol's proteins was a fishing expedition. Fishing expedition can be a derogatory term in biology but for us it was positive, since we caught some important "fish" that enable us to formulate hypotheses as to how limb regeneration occurs," said David L. Stocum, Ph.D., professor of biology and director of the Indiana University Center for Regenerative Biology and Medicine, both in the School of Science at IUPUI, who led the study.

"Comparison of these proteins to those expressed in the amputated frog limb, which regenerates poorly, will hopefully allow us to determine how we might enhance limb regeneration in the frog and ultimately in humans, Dr. Stocum said.
With few exceptions -- notably the antlers of moose, deer and their close relatives, the tips of the fingers and toes of humans and rodents, and the ear tissue of certain strains of mice and rabbits -- the appendages of mammals do not regenerate after amputation.

Limb regeneration in the axolotl occurs when undifferentiated cells accumulate under the wound epidermis at the amputation site, a process known as the establishment of a blastema. These cells are derived by the reprogramming of differentiated cells to a less specialized state, and from resident stem cells.
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