Xenotransplantation: The Future of Organ Transplantation
Healthcare | Feb, 2022
The increasing life expectancy of humans has led to
a rising number of patients living with chronic disorders, which may ultimately
require organ transplantation for the treatment of their condition and prevent
end-stage organ failure. Although clinical transplantation is an effective
solution to save lives, the imbalance between organ supply and demand for human
organs remains a challenge for the medical community.
According to organ donation statistics, 17 people
die each day waiting for an organ transplant. Hence, xenotransplantation, or
cross-species transplantation, is considered a promising alternative to resort
to the shortage of human tissues, prohibiting most patients from undergoing
transplants. The possibility of transplanting animal cells, tissues, or organs
in humans could improve mortality rates for conditions such as chronic
obstructive pulmonary disorders, diabetes, liver cirrhosis, polycystic kidney
diseases, etc.
Domestic Pigs: Optimum Organ Donor
Domestic pigs are considered the best donors of
biological materials for xenotransplantation due to their anatomical and
physiological similarities to humans, low risk of xenozoonosis, short
maturation period, and large litter size. One major obstacle with
xenotransplantation is transplant failure, as the body mounts an immune
response against the xenografts (transplanted organ or tissue) and rejects it,
which could result in the recipient's death.
Hence, the genes of domestic pigs are modified to
prevent the recognition of their organs by the human recipient’s immune system
and inhibit the process leading to xenograft rejection. Genetically engineered
proteins express the human CD47 protein that reduces the risk of organ
rejection, and the immune-suppressing drugs target coagulation and
inflammation, which increase the duration of organ function. Several techniques
that enable precise genetic modification of animals include pronuclear or
cytoplasmic microinjection, somatic cell nuclear transfer, viral transduction
of DNA.