Xenotransplantation is CCP's "Great Leap Forward" in Technology Field
By Sean Lin
(Jennifer’ note: Sean Lin is a microbiologist and a former lab director of the viral disease branch of the Walter Reed Army Institute of Research. Below are his comments when I asked him to comment on the Xenotransplants from pigs, which I discussed in my latest show. )
Porcine industry often suffers from waves of economic loss from death or diseases caused by various pathogen infections. The diseases associated with swine often include ringworm, erysipelas, leptospirosis, streptococcosis, campylobacterosis, salmonellosis, cryptosporidiosis, giardiasis, balantidiasis, infection with pathogenic E. coli, brucellosis, as well as diseases caused many viral pathogens such as swine influenza virus, swine fever virus, porcine reproductive and respiratory syndrome virus (PRRSV), etc. So, one of the major risks associated with xenotransplantation with pig organs is whether the recipients would become more susceptible to various infections, or whether the recipients would carry swine-related pathogens that are with pig organs prior to the xenotransplant.
In addition, scientists do not always know the full spectrum of the consequences of genetic editing. For example, PRRSV is a nasty infection that causes huge economic losses across Europe, Asia, and North America. PRRSV uses CD163 receptor, which is the receptor for the hemoglobin-haptoglobin complex or hemoglobin alone. Scientists have used genetic editing tools to knock down or alter CD163 in pig embryos and the pig offspring becomes resistant to PRRSV infection. However, one potential consequence is that the genetically edited pig might become more vulnerable for other bacteria infection since CD163 functions as an innate immune sensor for some gram-positive and gram-negative bacteria.
The scary part of the work done by scientists at Qihan Biotech and eGenesis is the extensive genetic editing (13 genes and 42 alleles) without comprehensive knowledge on the multifaceted consequence of the edits. The porcine endogenous retroviruses (PERVs) genes were inactivated in this experiment, but it is not known whether this would lead to any aberrant expression of partial viral genes or host genes. This experiment used a combination of CRISPR–Cas9 and transposon technologies to eliminate three xenoantigens and to express nine human transgenes that enhance the pigs’ immunological compatibility and blood-coagulation compatibility with humans. Although the engineered pigs exhibit normal physiology and fertility, it is not clear whether the engineered pigs can lead to unexpected cell or organ damages and pathogenesis associated with dysregulated coagulation.
The Chinese government has invested heavily to drive forward the gene editing experiments, just as they carried out the political “Great-Leap forward” movement in history. Xenotransplants from pigs to primates are subject to vigorous immunologic rejection involving both innate and adaptive immune responses. It is unavoidable that more extensive genetic editing will need to be engineered down this road. And since the bioethics review process is nearly nonexistent in national priority projects driven by Chinese regime, the paramount risk is that xenotransplantation to humans could be prematurely conducted, based on limited knowledge on xenotransplant of pig organs to non-human primates.
7/6/2021*
