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Regenerating human limbs on demand

September 03, 2015

Excerpted from "Out on a limb: Pioneering scientists grow monkey arms in the lab," CNN. August 11, 2015 — In a U.S. laboratory, a monkey arm is stripped down as far as its individual cells. All that's left behind is a bare, frail scaffold. But that's not the end of the road for this arm. The scaffold is rebuilt with infusions of cells from another being -- be it a monkey, or a human -- which grow and transform the limb.

The aim is ultimately to restore the limb to its fully functional form. But this transformed limb will contain the blood, bones, muscles, cartilage -- and more -- not of the animal it once was, but instead, the animal providing these new cells. The hope is to eventually use human cells to make limbs that can be transplanted in humans -- and the technology is already being trialled in monkeys.

"There are no good options to replace lost limbs," says Harald Ott, director of the organ repair and regeneration lab at Massachusetts General Hospital (MGH), in Boston, who is leading this research.

The current options for amputees are a diverse range of prosthetics -- incorporating many new forms of technology to help them feel real -- or transplants, when matching donors are available. But with these options come limitations in terms of movement and control. In the case of transplants, the limiting factor is the need for life-long immunosuppressive drugs to stop a recipient's immune system from attacking their new limb. Suppressing immunity in this way opens up the risk of new infections and certain cancers.

Ott's ambitious technique therefore has an ambitious goal -- to one day provide amputees with fully functional limbs that can be transplanted as if they were their own. The idea is to create limbs made up of cells from the amputee's own body to produce an arm -- or one day leg -- tailored to them and therefore unlikely to be attacked by their immune system. "If it works out you could regenerate ... on demand," says Ott.

To date, Ott has managed to use this technique to grow organs -- including lungs and a beating heart -- and in June 2015, successfully extended it further to regenerate the arm of a rat in his lab.

He has now scaled things up -- to monkeys.

To do this, Ott is using what is known as progenitor cells, which have the ability to differentiate into a wide range of cell types -- such as blood or muscle cells -- within the body. They are similar to stem cells but slightly more specialized making them more easily pushed into creating the specific cells desired by the team.


Dr. John Fulginiti IIIInstitute for Human Flourishing Founder John Fulginiti III, MD, FACS, MA(CT): “Truly, truly remarkable and truly hopeful! CNN’s report on the work of Dr. Ott is exciting news for patients debilitated, often severely, by amputations, spinal cord injuries and dementia, all of whom now have more hope of receiving definitive treatment one day. It appears that this work is an exemplar of the ethically unproblematic use of adult stem cell/progenitor cells.

“Not to be naïve, we recognize that this work has antecedents in ethically problematic areas such as embryonic stem cell technologies, ART and abortion. The web of related issues is complex. This announcement is a stark bookend to the recent revelations about fetal harvesting by Planned Parenthood.

“Despite the ethical ambiguities surrounding many biotechnical advances, we do well to remember that God works providentially through His image bearers. His love, power and wisdom are displayed through Dr. Ott’s team, his image bearers, given that they are acting: in accord with positive aspects of the sixth commandment, in love, knowledge, wisdom, creativity and artistry.

“All of these reflect God’s gracious character. Recognizing that we are imaging (as well as commanded to glorify) God as we help others flourish should ground and guide us as we develop and use these powerful, life enhancing biotechnologies. Dr. Ott’s remarkable accomplishment seems to be consistent with ethically licit practices and glorifies God in working toward helpful therapies. It adds to the growing body of positive outcomes using adult stem/progenitor cells. This type of work should continue and be funded preferentially over embryonic stem cell research.”


CMDA’s Ethics Statement on Human Stem Cell Research
Scientific Demagoguery in the Stem Cell Wars by David Stevens, MD, MA (Ethics)
Standards for Life – Stem Cell Research

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