On January 7, the world's first pig heart transplant was successful!

David Bennett, 57, has had an 'experimental' heart transplant

The heart came from a 1-year-old, 240-pound "transgenic" pig

Gene modification is the use of molecular biology techniques to remove parts of animal genes that are prone to rejection, so that the transplanted animal organs can be compatible with the human body and survive for a long time

The University of Maryland Medical Center (UMMC), which performed the operation, officially announced that this is the world's first transgenic pig heart transplant

On January 10, local time, the third day after the operation

"Die or transplant a pig's heart," Bennett said the day before the surgery, who knew his condition very well

He said he had a valve transplant from a pig and his favorite food was bacon

Bennett developed end-stage heart failure due to a complex genetic heart condition

His treatment plan was difficult to formulate

Even if he's on the list, Bennett's chances of getting an organ in time are slim

According to the United Network for Organ Sharing (UNOS), approximately 41,354 Americans will receive organ transplants in 2021, including more than 3,800 heart transplants

According to U.

UMMC proposes "another possibility": xenotransplantation, life-saving surgery using animal organs

According to the BBC, xenotransplantation dates back to 1682

At the time, Dutch surgeon Jan Zorn van Mickelen said he used a fragment of a dog bone to repair a soldier's skull

The soldier's follow-up is unclear

Since the 20th century, relevant surgical reports have emerged in an endless stream
.

In 1905, France completed the world's first human transplant of rabbit kidney slices
.
The recipient is a child with kidney failure
.
16 days after surgery, the patient died of lung infection due to rejection
.

The following year, also in France, a pig kidney and a goat liver were transplanted into two female patients
.
Both died shortly after surgery from serious infections caused by taking immunosuppressive drugs
.

In 1984 and 1992, doctors performed human transplants using baboon hearts and livers, respectively
.
The patient died of rejection within a few weeks of surgery
.

In 2003, xenotransplantation entered a new phase
.
The American company Revivicor creatively carried out genetic modification on cloned pigs and cultivated the first generation of "medical pigs"
.
This is listed as one of the 100 major scientific discoveries of the year by the American "Discovery" magazine
.

The name Revivicor may not be widely known, but its predecessor PPL Therapeutics, a biotech company, has made a name for itself - it created the world's first cloned sheep "Dolly"
.

The question is, why did Revivicor choose cloven-hoofed pigs for the study, and forgo primates that are species and anatomically similar to humans, such as orangutans and baboons?

The analysis of Revivicor pointed out that because "Second Brother" is very useful
.

Pigs and humans have similar dietary habits and metabolic levels, as well as similar body temperature and heart rate
.

The "performance parameters" of some organs in pigs are also similar to those in humans
.
For example, a pig's heart is about the same size as a human heart and has a similar distribution of conduits and power output
.

Also, primates have a long generation gap
.
In particular, orangutans and baboons have a 10-year-old generation, one litter and one cub, and raising them is expensive
.
Pigs are raised in one litter and mature for more than one year, which is suitable for directional breeding and large-scale breeding
.

More importantly, orangutans and baboons are "close relatives" of humans
.
Some viruses in it, such as simian immunodeficiency virus, are easily transmitted to humans
.
More powerful viruses may hatch when their organs are transplanted into humans
.

Viruses in pigs are less likely to infect humans
.
In 2015, a research team from Harvard University in the United States used gene editing technology to knock out the endogenous retrovirus PERV (endogenous retrovirus) in the genome of the pig population, eliminating the hidden danger of pig organ transplantation
.

Previous studies have shown that pig cells containing PERV viroids are at risk of being activated and infecting human cells when incubated with human tissue
.

It has become an international consensus that pigs are the best choice for xenotransplantation
.

At present, pig heart valve and pig pancreas cells have successfully entered the human body
.
Pig skins are also used as temporary transplant organs for burn patients
.

In December 2018, the journal Nature published the amazing results of Bruno Reichart's team successfully transforming the heart of a transgenic pig, transplanting it into a baboon, and the longest survival time was 6 months
.

Two years later, the journal Circulation published an article at Massachusetts General Hospital saying pig hearts were promising donors for human heart transplants
.

The article predicts that humans may receive pig heart transplants as early as the end of 2021
.
 

This prediction now seems accurate
.

On December 31, 2021, the U.
S.
Food and Drug Administration (FDA) granted an "emergency authorization" for David Bennett's experimental surgery through a "compassionate use" provision
.

The pig heart donor used in the surgery was from Revivicor
.

The dedicated pig received 10 unique genetic modifications, UMMC said
.
Including knockout of 3 genes to reduce aggressive rejection by the human immune system
.

Knockout of 1 growth gene prevents the pig heart from continuing to grow after transplantation
.

In addition, six human genes were edited and inserted into the donor pig genome
.
The goal is to make pig organs more resistant to the human immune system
.

UMMC also uses an innovative drug to prevent rejection after organ transplants
.

The genetically modified animal organs worked in Bennett's body and were not immediately rejected, UMMC said
.
The results of this surgery could change the fate of many people around the world
.

"We've never done anything like that in humans
.
I think we've given him a better treatment option than continuing to take medication
.
All the risks and rewards are unknown .
Will
he live a day, a week, a month or a month.
Years, I don't know
.
"

"This was a watershed event," said Robert A Montgomery, director of the Transplant Institute at NYU Langone Medical Center
.

In October 2021, with the consent of the patient's family, Montgomery also completed a xenograft operation
.

He transplanted the kidney of a genetically modified pig into a brain-dead patient with end-stage renal disease
.

This surgical method is different from an actual transplant
.
The pig kidney was not implanted in the patient, but was attached to the outer thigh vessel of the patient's abdomen
.

This is because in xenograft surgery, problems often occur at the anastomosis site of human blood vessels and animal organs
.

"The transplanted organ worked almost immediately," Montgomery told The New York Times.
"
The fact that the organ worked outside the body is a strong indication that it also worked well inside the body
.
"

In response to the widespread concern of patients and the media "when will xenotransplantation be widely promoted", the UMMC team said that there are still many questions that need to be answered
.

According to the opinion of the International Xenotransplantation Steering Committee, the precondition for xenotransplantation research to enter the clinic is that 60% of the animal experimental recipients survive for more than 3 months, and there are at least 10 consecutive transplantation experiments
.

The goal of this clinical trial is to permanently replace the original organ, and more than 50 percent of recipients must survive for more than 6 months
.

The next six months will be especially important for Bennett and the transplant community
.

"If successful, genetically modified pigs could become a sustainable, renewable source of organs equivalent to the solar and wind energy that organs provide," Montgomery told The New York Times
.

At present, the production capacity and production license of these "medical pigs" are guaranteed
.

In December 2020, the US FDA issued a sales license to Revivicor's genetically modified pig GalSafe
.

Unlike conventional pigs, GalSafe pigs are knocked out of the alpha-galactose molecule on the cell surface
.
This molecule is widely found on the cell surface of pigs, sheep, cattle and other "red meat" animals
.
Some people have allergic reactions to red meat, and they all rely on it
.

In addition to being allergenic, alpha-galactose molecules are also one of the main causes of immune rejection
.
Because after evolution to primates, there is no galactose in the body
.

According to the FDA, GalSafe pigs can be eaten directly or used to process and produce galactose-free medical products, such as the blood-thinning drug heparin
.

Revivicor's best hope for GalSafe pigs is to produce organs for xenotransplantation
.

In 2017, Smithfield Foods, the world's largest pork producer, announced the creation of a new independent bioscience unit dedicated to raising "medical pigs" in hopes of forming a chain of pig organs for human transplants
.

The pigs were allegedly delivered by caesarean section, separated from their mothers immediately after birth, and sent to ultra-clean pig houses for captivity
.

The pig house is sterile and non-toxic, and the breeding staff should take a bath and change clothes before entering the pig house
.
All in all, it's cleaner than some places
.

(Source: Internet, reference only)