(ORDO NEWS) — In the organ, before and after transplantation, there were malfunctions in the operation of cellular systems responsible for the transmission of electrical signals.
Doctors studied the heart rate of a pig implanted in 57-year-old David Bennett in January of this year.
The team identified previously unknown anomalies in the functioning of the organ that arose after transplantation into the patient’s body.
Xenotransplantation (transplantation of organs from an animal to a person) has long been hampered by the fact that the immune system rejects foreign tissues.
Biologists solved the problem when they adapted the CRISPR/Cas9 genomic editor to remove the genes responsible for the operation of the “friend or foe” system.
CRISPR/Cas9 is a kind of molecular scissors that cut DNA. With the help of this system, a fragment can be deleted, changed or inserted in the genome – as a result, the features of the organism will change.
Thanks to this, the researchers were able to transplant the heart of a pig, first into the body of a baboon, and then into the chest of 57-year-old David Bennett.
Initially, the team found no problems with the implanted heart, but two months after the operation, the man died unexpectedly. This has caused controversy surrounding the safety of xenotransplantation.
Electrical anomalies in the work of the heart
The team looked at the options that caused the patient to develop diastolic heart failure. However, they were unable to detect physical or biochemical traces showing that the volunteer’s immune system had rejected the transplanted heart.
For this reason, the researchers continued to search for the cause of death of the volunteer. To do this, they re-examined the ECG taken after heart implantation. Scientists compared the indicators with measurements of healthy pig organs.
The comparison revealed anomalies in the implanted heart’s heart rhythms that escaped the attention of scientists during the operation.
The team found that three ECG parameters – PR, QRS and QT – were significantly higher in the transplanted heart than similar values found not only in healthy pig organs, but also in humans.
They remained abnormally high for two months after the operation, which indicates the presence of serious malfunctions in the cellular systems responsible for the transmission of electrical signals inside the heart.
The researchers hope that subsequent experiments, as well as a detailed study of the consequences of DNA editing and the transplant procedure itself, will help to identify the causes of electrical and other anomalies in the heart.
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