If you have a terminal heart attack, you can only survive with a heart transplant. At this time, the doctor told you that you could transplant a heart from a pig for you, would you agree?
Recently, the University of Maryland Medical Center in the United States completed this unprecedented operation.
The surgical team successfully completed a heart transplant for a 57-year-old man with a late heart attack, the donor came from a genetically modified pig heart, 4 days after the operation, the patient's personal condition was stable, and the heart worked well after transplantation.
(The world's first swine heart transplant patient and doctor.) Source: University of Maryland School of Medicine website)
This is another major breakthrough in the history of human medicine. But there are still many people who want to ask: why choose the heart of the pig? Do you have to transplant the heart of a pig?
Today's article, we will come to popularize the "pig heart transplantation" thing.
First of all, you must want to ask: why not use the human heart? Won't there be a question of medical ethics?
This is because, all along, the heart source donor has been extremely scarce, coupled with the difficulty of matching, which seriously restricts the development of heart transplantation technology, often so that many heart disease patients fall into the desperate situation of "no heart to move".
It was precisely because there was no matching suitable human donor heart that in the end, the doctors at the University of Maryland School of Medicine decided to adopt a "pig heart" transplant for him.
(Source: University of Maryland School of Medicine website)
So why choose the heart of a pig instead of a primate like a monkey or an orangutan that is more like a human?
The first is because of the tight time and long cycle. Monkeys, orangutans and other primates grow for a very long time, often more than 10 years of cultivation time to reach a similar level with the human body, and they themselves are nationally protected animals, the reproductive rate is not high, not to mention a litter, the cost of breeding is also very high.
Heart patients with severe heart failure and heart transplants often find it difficult to wait that long. Patients who need heart transplants are often in a very urgent state, and it can be said that a little earlier transplantation will have more possibilities to survive.
The patient who received a pig heart transplant, who had been bedridden for months before the transplant, said himself:
"Die or have a transplant. I want to live. It was an attempt in the dark, but it was my last resort. ”
Secondly, the size of the pig heart, cardiovascular, atrial distribution and other anatomical structures, hemodynamic level are very similar to the human body. In addition, the breeding and breeding costs of pigs are relatively low, so it has become the best "heart" choice for animal organ transplantation at present.
You may be thinking: Since the heart of the pig can save life, if you eat the heart of the pig in the future, is it too "wasteful"?
No! Pigs, which are donors of pig hearts, are not a kind of pig and what we usually buy in the wet market.
All organ transplants, even those of humans as donors, fear "immune rejection" [7].
The doctor dared to use the "pig heart" this time, and the reason was: this donor pig is not simple!
The "pig heart transplant" of the University of Maryland School of Medicine in the United States, as of 4 days after the operation, the patient's condition is still good.
This is because the pig hearts used in the operation are not ordinary pigs from pig farms, but "special pigs" that have been carefully prepared by medical companies nearly a year in advance.
The researchers carried out 10 gene modifications on this donor pig, not only knocking out 3 genes that will quickly cause human immune rejection, but also artificially adding 6 human-specific genomes to enhance the pig's tolerance to the human immune system, which has today's miracle.
It can be said that behind this seemingly simple operation is the deep support of modern technology and the magnificent development of medical treatment.
You may also want to ask: Good people do not need to use the heart of a pig, why bother with the heart of a pig?
One of the most important reasons is simple: there are not enough human donors.
Academician Zheng Shusen, president of the Organ Transplant Physician Branch of the Chinese Medical Doctor Association, said in an interview: "At present, the number of organ donations in China has ranked first in Asia and second in the world. In 2021, a total of 4163 cases of organ donation were carried out in China, and 4620 cases of liver transplantation, 9392 cases of kidney transplantation, 602 cases of lung transplantation, and 583 cases of heart transplantation were carried out. ”
If you take a closer look, it's not hard to see that heart transplants account for the smallest proportion.
Regardless of the liver, kidneys, lungs, part of the organ donation can be realized, that is, to donate one side, half, part of the organ, but also to meet the use and life support of the donor.
But heart transplantation is different, if you want to donate, you must donate the entire heart. This means that the donor must be dead, so the "heart source" is extremely scarce.
Behind the so-called "smart woman is difficult to cook without rice", behind the lack of heart sources, there are many patients who are struggling on the line of life and death, waiting for heart donors.
At present, there are about 300 to 400 cases of heart transplantation in China every year, and the average survival time of patients after heart transplantation is 13 years, with a three-year survival rate of more than 90% and a five-year survival rate of more than 85% [6].
That is to say, if they can successfully receive a heart transplant, the patient is still very hopeful to continue to live, have a good quality of life, have more time to complete their wishes, and spend time with their families, rather than lying in a hospital bed and looking forward to the miracle.
(In 2018, the number of heart transplant cases in China ranked among the top 10 medical institutions.)
Source: Report on the Development of Organ Transplantation in China (2019))
Heart transplantation seems to be very easy to carry out, but in fact, there are still great difficulties, including lack of donors, difficulty in matching, complicated surgery, and many postoperative complications [8].
Therefore, whether it is a medical practitioner, or a heart disease patient and his family, I believe that many people are paying attention to the follow-up development of this patient who has received a pig heart transplant.
What will happen to the 57-year-old man and how old will he live? Can this technology be widely used in the future? Will it be expensive or have other problems? We don't know yet.
But at the time of writing this article, DianGe consulted the materials on the situation of organ transplantation in our country and found that:
China completed 19,454 organ transplants in 2020, ranking second in the world in the number of annual organ transplants.
However, due to the shortage of organ donors, the development of various transplants is still very limited. In recent years, the number of organ donations after death in China has been insufficient, far from meeting the demand for about 300,000 organ transplants in China every year [10].
(Report on the Development of Organ Transplantation in China (2019))
Therefore, to see you here, Dian Ge would like to say:
If you wish, after full consideration, you may choose to register as an organ donor volunteer.
After all, while looking forward to the development of "pig heart" transplants and other technologies, more patients with similar experiences are still waiting for the miracle of their lives.
In the current field of organ transplantation, more people's kindness and kindness are still needed.
It is a gift from one life to another, and it is also a transmission of love.
Expert reviews
Review expert: Zhang Haibo
Chief Physician of the Department of Cardiac Surgery, Beijing Anzhen Hospital, Capital Medical University
(Slide down to see more)
One of the reasons for the more restrictive donation of heart transplant donors is that surgical techniques and perioperative management are complex and can only be performed in large experienced cardiac surgery teams.
The number of hospitals that carry out heart transplants is far less than the number of hospitals for liver and kidney transplants. In addition, the heart tolerates ischemia for about six hours, and the shortest in organ transplantation, so it is limited by geographical area.
Xenotransplantations similar to "pig heart" transplants, from the early stages of heart transplantation in the 1970s, have been tried by baboons and pig hearts, but both have failed due to severe super rejection.
Later, xenotransplantation made great progress under the advancement of gene editing and knockout technology, and gradually became a research hotspot in these years, until this operation made a breakthrough.
In addition, regarding artificial heart technology, in recent years, because of the lack of heart transplant donors, in addition to xenotransplantation research, artificial heart assistive technology has also developed rapidly, and there have been some successful cases for more than a decade, but because the price is very expensive, and there is a risk of bleeding and thrombosis, most patients with artificial heart assistance have to transition to heart transplantation, so the success rate of artificial heart technology is not as good as heart transplantation.
At present, this case has just been successful for a few days, which means that it has basically passed the super rejection stage, and now faces the most common acute rejection test in a few months.
At this stage, the use strategy of immunosuppressive drugs is also a major test and accumulation of experience. We'll all be waiting to see and look forward to a deeper understanding of the success of xenotransplantation.
Special Author: Liu Pengran
Doctoral student of Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology
Review expert: Han Bo
Attending physician of the Department of Cardiac Surgery, Beijing Anzhen Hospital affiliated to Capital Medical University
bibliography
[1]https://www.medschool.umaryland.edu/news/2022/University-of-Maryland-School-of-Medicine-Faculty-Scientists-and-Clinicians-Perform-Historic-First-Successful-Transplant-of-Porcine-Heart-into-Adult-Human-with-End-Stage-Heart-Disease.html
Chen Pengfei,Nie Huirong,Dai Yifan,Cai Zhiming,Mou Lisha. Research progress of genetically modified pigs in xenotransplantation[J].Chinese Journal of Transplantation (Electronic Edition), 2017,11(02):119-124.
Deng Fuying,Xu Jiali,Wei Xiaoqiu,Zeng Xiaohui,Wen Hong,Zhu Ruiping. Nursing coordination of in-situ heart transplantation of Bama small pigs without stopping jumping[J].Chinese Journal of Clinical New Medicine,2014,7(12):1163-1165.
[4] Han let the transplanted pig heart and pig kidney monkeys survive for more than 20 days[J].Teaching of Biology,2012,37(12):74.
[5] Mohiuddin MM, Singh AK, Corcoran PC, Thomas Iii ML, Clark T, Lewis BG, Hoyt RF, Eckhaus M, Pierson Iii RN, Belli AJ, Wolf E, Klymiuk N, Phelps C, Reimann KA, Ayares D, Horvath KA. Chimeric 2C10R4 anti-CD40 antibody therapy is critical for long-term survival of GTKO.hCD46.hTBM pig-to-primate cardiac xenograft. Nat Commun. 2016 Apr 5;7:11138.
Zheng Shusen. Current situation of organ donation and transplantation in China[J].Journal of Wuhan University (Medical Scienc),2016,37(04):523-525.
Zou Junyi, Zhang Hui, Zhang Xinjie, Li Zijia, Xu Minglei, Wang Dong.Clinical experience of 110 cases of in situ heart transplantation[J].Journal of Shandong University (Medical Edition),2021,59(08):86-91.
Jing Qiming,Wang Rui,Chen Xin. Clinical analysis of 36 cases of allogeneic in situ heart transplantation[J].Chinese Clinical Journal of Thoracic and Cardiovascular Surgery,2019,26(10):968-972.
Chen Meifang. Chinese Standards for diagnosis and treatment of postoperative complications of heart transplantation (2019 edition)[J].Chinese Journal of Transplantation (Electronic Edition), 2019,13(01):21-23.
[10] Jiefu Huang, China Organ Transplant Development Foundation, China Organ Transplant Development Report (2015-2018)
Editors: Ye Zhengxing, Di Hao, Zhang Liang
Typesetting: Han Ningning | Proofreader: Wu Yihe
Operations: Li Yongmin | Coordinator: Wu Wei