Novel Coating Might Curb Organ Transplant Rejection

Using immunosuppressive polymers to coat blood vessels of organs for transplant can substantially diminish rejection, according to a new study.

Developed at the University of British Columbia (UBC; Vancouver, Canada), Simon Fraser University (Burnaby, Canada), and other institutions, the new synthetic polymer is designed to mimic glycocalyx, an immune-modulating protein that lines blood vessels, which tends to break down during organ procurement as a result of enzymatic ligation of the glycopolymers used during cold ischemic storage. In addition, this ligation subsequently attenuates the acute and chronic rejection of the grafts after transplantation.

For the study, conducted in syngeneic and allogeneic mice that received kidney transplants, the steric and immunosuppressive properties of the ligated polymers largely protected the transplanted grafts from ischaemic reperfusion injury and immune-cell adhesion. A mouse artery coated with the polymer and then transplanted exhibited strong long-term resistance to inflammation and rejection. According to the researchers, the polymer-mediated shielding of endothelial glycocalyx could also reduce the damage and rejection of transplanted organs after surgery. The study was published on August 9, 2021, in Nature Biomedical Engineering.

“We demonstrated that the technology works for blood vessel and complex kidney transplantation in mice. However, the immune system of these animals is slightly different than in humans,” said senior author Jayachandran Kizhakkedathu, PhD, who developed the polymer at the UBC Centre for Blood Research. “Our next step is to investigate the protective effect of the technology in large animal transplantation, including non-human primates. We’re hopeful that this breakthrough will one day improve quality of life for transplant patients and improve the lifespan of transplanted organs.”

The cornerstone of traditional organ preservation is cold ischemic storage. Although this method is intended to reduce the extent of organ damage during transport, significant deterioration of the donated organ still occurs; the longer the organ is kept on ice, the greater the damage.

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University of British Columbia
Simon Fraser University