Skip to main content



Xenotransplantation is the process of transplanting viable organs or tissues between two different species. Organs from ordinary pigs are rejected almost immediately when transplanted into other species, including humans. To overcome rejection and make organs suitable for transplant into human patients, Revivicor has edited 10 genes in the pig genome. Three of these genes were silenced to prevent rejection, one was silenced to limit organ growth after transplant, and six human genes were inserted to prevent rejection, inflammation, and blood clot formation in the transplanted organ.

Xeno organs are development-stage technologies.

Precision Gene Editing

Revivicor uses precision gene editing technologies to silence or insert genes in the pig genome. Gene editing is carried out in pig cells cultured in a petri dish. The cells are screened and analyzed to ensure accurate gene editing.

Somatic Cell Nuclear Transfer

Somatic cell nuclear transfer (SCNT) is used to generate pigs from the gene edited cells. Based on a method developed in sheep, Revivicor pioneered the technique of SCNT in pigs over two decades ago. As the name implies, SCNT involves the transfer of a nucleus from a gene edited pig cell into a pig egg from which the egg nucleus has been removed. The eggs are then transferred to surrogate sows where they develop and grow until natural birth. All pigs born are composed of cells bearing the gene edits inherited from the edited nuclei used for SCNT. The organs of resulting pigs will express the characteristics and benefits of the edited genes.

Screening and Analysis

Prior to transplant, pigs are screened and analyzed to confirm the presence and integrity of the intended gene edits. In addition, cells from each pig are evaluated to confirm that each edit functions as intended.

Designated Pathogen-Free Pigs

Revivicor will raise organ donor pigs in a designated pathogen-free facility to eliminate microorganisms that could transmit disease to human transplant recipients.


Xenohearts are genetically engineered pig hearts that provide a scalable heart transplant solution for end-stage cardiac disease.


Xenokidneys are genetically engineered pig kidneys that provide a scalable kidney transplant solution for end-stage renal disease.

UHeart™ and UKidney™ are development-stage products not approved for sale in any jurisdiction.

GalSafe™ Gene Editing

GalSafe™ Application

Products derived from the GalSafe™ pig are intended as sources of food or human therapeutics including excipients, devices, drugs or biological products that are free of detectable alpha-gal sugars. Tissues and organs from GalSafe™ pigs could address the issue of immune rejection in patients receiving xenografts, as alpha-gal sugar is believed to be a cause of rejection in patients. Food products made from GalSafe™ pigs may provide a red meat option for people with alpha-gal syndrome. People with alpha-gal syndrome have mild to severe allergic reactions to alpha-gal sugars found in red meat (e.g., beef, pork, and lamb).

Standard Pig DNA

Active GGTA1 Gene

GalSafe™ Pig DNA

Inactivated GGTA1 Gene

Alpha-Gal Syndrome Red Meat Allergy

All food producing mammals have an active GGTA1 gene and express galactose-alpha-1,3-galactose sugar moieties commonly known as "alpha-gal" on organs, tissues, cells including all food and therapeutic products. The GGTA1 gene in the GalSafe™ pig has been inactivated and has undetectable levels of alpha-gal.

Lonestar tick
  • feeds on blood
  • spread by deer
2 Humans encounter ticks
3 ~1-3 months after a tick bite the affected person develops elevated IgE levels to alpha-gal
4 Exposure to food or medical products from food producing mammals
5 Delayed response 2-6 hours later
  • hives and itching
  • swollen tongue or throat
  • trouble breathing
  • weak and rapid heartbeat
  • nausea, vomiting, or diarrhea
  • dizziness or fainting

Image adapted from The alpha-gal story: lessons learned from connecting the dots

GalSafe™ Food Products

The FDA has approved the GalSafe™ pig as a source of food for human consumption. The USDA review resulted in our GalSafe™ food products bearing the label claim:

Galsafe Label 1
Galsafe Label 2


Xenokidneys are kidneys from galsafe pigs which have been genetically engineered to be transplanted into patients with end-stage renal disease.

More information about UThymoKidney™

UThymoKidney™ is a development-stage product not approved for sale in any jurisdiction.