2023-10-12 11:48:29
A kidney, transplanted from a dwarf pig [1] genetically modified, was implanted into a monkey who was able to stay alive for ” more than two years “. It is ” one of the longest survival times for an interspecies organ transplant », Say the researchers.
For Wenning Qin, molecular biologist at eGenesisa biotechnology company in Cambridge, Massachusetts, and co-author of the study published in Nature October 11 [2]It’s regarding a ” proof of principle in non-human primates » : « Our organ [génétiquement modifié] is safe and life-sustaining », he assures (see 17 macaques grafted with pig kidneys).
69 genetic modifications
The researchers edited 69 genes, “ which represents the largest edition carried out on live pigs for xenotransplantation » (cf. Human-animal chimeras: animal defense associations rise up). Three modifications target molecules related to shedding, and 59 modifications target retrovirus genomes that can produce viral particles that can infect human cells. The last seven modifications are “ additions of human genes » which contribute to « keep the transplanted organ healthy “. Two genes, for example, encode proteins that prevent coagulation inutile » you sang.
However, scientists wonder regarding the possibility of “ mass produce » pigs having undergone “ modification so extensive » (cf. A German researcher launches into breeding pigs for xenografts). Megan Sykes, transplant immunologist at Columbia University Medical Center of New York, also questions the need to carry out such numerous genetic modifications. The survival time is not much better than those previously obtained with “ much less genetic modification “, she assures.
More than 20 macaques transplanted
More than 20 cynomolgus macaques have undergone pig kidney transplants. They also received “ a cocktail of immunosuppressive drugs ».
None of the monkeys given kidneys lacking all seven human genes survived more than 50 days. In contrast, 9 of 15 monkeys given kidneys with human genes survived. Five of these monkeys lived more than a year, and one of them more than two years.
Wenning Qin acknowledges that survival times have been “ more varied than the team expected ».
Towards a trial on humans?
According to the researchers, this study will provide more data to regulatory bodies such as the Food and Drug Administration (FDA), which is currently studying the possibility of approving the first transplant trials of “ non-human organs » on humans (cf. A new patient transplanted with a pig’s heart).
Jayme Locke, a transplant surgeon at the University of Alabama at Birmingham, believes, however, that ” the transition to humans will not be trivial ». « Humans weigh much more and have higher blood pressure than these apes, and it’s unclear whether pig organs will withstand this environment. “, she argues.
[1] A species of pig also called pygmy pig. The researchers used kidneys from dwarf pigs because “ organs transplanted from conventional pigs grow rapidly in recipients, potentially compromising the grafts “. Some researchers have tried to deactivate the porcine genes responsible for this growth, which induced “ complications “, specifies Muhammad Mohiuddin, surgeon specializing in xenotransplantation at the University of Maryland School of Medicine, in Baltimore. The organs of dwarf pigs develop more slowly.
[2] Anand, R.P., Layer, J.V., Heja, D., Hlrose, T. et al. (2023). Design and testing of a humanized porcine donor for xenotransplantation. Nature.
Source : Nature, Max Kozlov (11/10/2023)
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