Israeli surgeons first to freeze, defrost and transplant limb on rat

Procedure could lead to ‘organ banks’ for new types of human organ replacement surgeries.

By
April 26, 2017 18:36
3 minute read.
rat

A rat . (photo credit: REUTERS)

Plastic surgeons at Tel Aviv Sourasky Medical Center have reportedly become first in the world to freeze and re-implant a complete limb on rats. The breakthrough achievement has just been published in the American Journal of Transplantation.

The advance could lead to “organ banking” of complex organs and tissues – perhaps even faces and whole hands – for reconstructive procedures.

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Researchers at the plastic surgery lab at Sourasky’s Ichilov Hospital used two methods: slow freezing and vitrification – also known as cryopreservation, which solidifies without forming ice crystals – of a whole and complex organ. The achievement elicited great curiosity in the medical world, as the research success may lead to innovative technologies for the preservation of complex tissues, limbs and whole organs for future transplants.

A large number of transplants using hands and faces from foreign donors have been performed worldwide in recent years. This has created enormous potential for restoring quality of life to people with missing limbs or who need donor organs. However, limited availability of such organs and the need for immunosuppressive therapy to prevent rejection has limited face and hand transplants, and created a long queue for organ transplants in general.

Long-term preservation of organs in an organ bank could increase the availability of organs that are suitable aesthetically and functionally and may even improve immunological adaptation of tissues between donors and recipients.

The Sourasky research was a first step toward realizing that goal.

Plastic surgery department director Dr. Eyal Gur noted that “the need to replace ‘similar with similar’ is the principle guiding plastic surgeons in choosing the appropriate recovery option. So for complex deficiencies of different body regions, the patient’s own tissues can be used and restored with microsurgery.”

Where the situation is urgent, as for example in breast reconstruction, skin tissue and fat can be transferred from the abdomen to form a breast, which is now done on a daily basis.

But for larger or more complex deficits, such as restoring a complete hand or face, there are not yet ideal solutions, said Prof. Amir Arav, a world leader in cryo-biology.

Arav developed a method for the slow freezing of organs that made it possible to preserve the rat limb. Despite the enormous challenge of preserving a limb consisted of different tissues – bone, muscle, nerve and fat – the hospital researchers succeeded in proving the viability of the limb after freezing, defrosting and reconnecting it to the rat.

Dr. Nir Shani, head of the plastic surgery laboratory at Ichilov Medical Center, explained: “In the study, whole hind limbs of rats were frozen in a slow-freezing or vitrification method and kept frozen for one to four weeks.

After the freezing, the limbs were warmed and transplanted into the rats using a gentle micro-surgical technique for connecting the blood vessels. Immediately after the blood vessels were connected, hemorrhage ended and a change in color indicated proper blood flow and vitality. Three days later it was shown that the limb survived the process.”

Dr. Or Friedman, who wrote the paper, developed the experimental model and won the Kahn Fellowship, said that “the unique combination of the maturation of science and cryology technology developed by Prof. Arav, as well as the micro-surgical reconstruction capabilities developed by Prof. Gur, enabled us to become pioneers in the field.”

Last year, more than five million reconstructive procedures were performed in the US alone. The recent clinical successes of vascularized composite allotransplantations, including hand and face transplantations, established the tremendous potential of these life-enhancing reconstructions, the authors wrote in their paper.

“Nevertheless, due to limited availability and lifelong immunosuppression, application is limited. Long-term banking of composite transplants may increase the availability of aesthetically compatible parts with partial or complete HLA matching, reducing the risk of rejection and the immunosuppressive burden.”

HLA stands for human leukocyte antigen, the genetic tissue compatibility complex in the human body.

The authors concluded, “We believe that with further research and development, cryopreservation may lead to composite tissue banks.

This may lead to a paradigm shift” from occasional surgeries to wide-scale, well-planned, and better-controlled elective surgeries.


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