Humanized Kidney Grows in Pig Embryos

By Angelina W.

Each day, countless people wait for available organs to be transplanted into them so that they can continue living. However, as a result of a limited number of organs, those people are being tortured in eternal waiting. According to the United States Health Resources and Service Administration, an organization that provides fair health care to communities with the greatest needs in the country, approximately seventeen people die each day as a result of not being able to get an organ transplant in time (“Organ Donation Statistics”). The organization estimated that every ten minutes, a person is added to the transplant waiting list. Following the HRSA’s calculation, around 144 people are added to the transplant waiting list daily (“Organ Donation Statistics”). 

Organ transplantation poses a significant challenge in the world due to the constrained availability of viable organs. Transplanting organs can only occur through both live and deceased donors as long as blood and oxygen are maintained throughout the organs until the organs recover sufficiently. It is not guaranteed that doctors are able to successfully retrieve the organ in a healthy and undamaged state. Hence, the limited number of organs continues to contribute to an organ donor shortage crisis worldwide. 

Scientists have responded to this problem with a unique solution: growing organs and tissues in animals that can be transplanted into humans. Many challenges have arisen from this method, mainly concerning the question of whether human cells can endure and grow inside a foreign host. As a result of the different anatomy and biological needs of an animal compared to a human body, scientists attempted to induce pluripotent stem cells, cells that have the ability to undergo self-renewal and to give rise to all cells of the tissues of the body (Romito). Despite the scientists’ efforts, pluripotent stem cells often die when introduced into the animal, which pushed scientists to discover another method that ensures the complete transplantation of pluripotent stem cells. 

They turned to using pig embryos, genetically edited to grow human stem cells that later could be used for organ transplants for human bodies. Stem cell biologist Liangxue Lai, of the Guangzhou Institutes of Biomedicine and Health in China, has held numerous trials to improve the human’s adaptability and survivability and has succeeded in the perfect development of human cells in an animal. When the pig embryos were only single cells, the team genetically edited the cells to lack the two essential genes for kidney development by using the gene-editing tool CRISPR. The National Library of Medicine defines clustered regularly interspaced short palindromic repeats (CRISPR) as a gene editing technology that scientists use to modify and add genetic material to an organism’s DNA with little to no complications (Redman). This is a necessary step for the development of kidney cells since once pluripotent stem cells are injected into that space, kidney cells are able to start developing (Heidt). According to Genetic Engineering & Biotechnology News, a scientific magazine that specifically focuses on genetic engineering and technologies in the biotechnology industry, in September 2023, approximately 1820 embryos were transferred into 13 pigs, and after waiting for 25 to 28 days, scientists terminated gestation and extracted the embryos to determine whether the chimeras had successfully produced humanized kidneys. Micheal Le Page, a science journalist, defines chimeras as organisms or tissues that contain genetically different cells, often derived from other organisms (Le Page). In this study, the embryos would be considered chimeric as they are composed of human cells and other cells from different species to generate humanized kidneys. Researchers collected five chimeric embryos on different dates after implantation, two on the 25th day and three on the 28th day, where they found that the embryos contained 50 to 60 percent human cells and had structurally normal kidneys in their stage of development. 

Researchers have successfully experimented with pig embryos and have been able to develop a solid human organ inside a different biological animal. This has shown an innovative solution to address the problem of human organ shortage for transplantation. Although scientists are still in the process of investigating and developing a complete protocol for growing humanized organs in different species, this milestone ultimately advances the field of regenerative medicine and raises the possibility of eliminating organ scarcity in the world. The researchers’ scientific triumph in genetic engineering could potentially revolutionize organ transplantation as it could offer an endless supply of organs for those in need. 

Despite scientists’ proposed alternatives to mitigate the issue of organ shortage, they must discern the public’s perception of having an organ that grew in a different biological animal transplanted in them. Some people may be concerned about the welfare of animals being experimented on and the ethical ramifications of carrying out an experiment that may contradict the laws of nature. Others will undoubtedly recognize the remarkable achievements of developing a humanized kidney in a pig’s embryo as it serves as a groundbreaking stride in the field of genetic engineering and a viable alternative for hospitals to offer to people who need organ transplantation in the future.

References

Bhadramani, Rasi. “In a First, Solid Humanized Kidneys Grown Inside Pigs.” Genetic Engineering & Biotechnology News. 8 Sept. 2023. www.genengnews.com/topics/translational-medicine/in-a-first-solid-humanized-kidneys-grown-inside-pigs/#:~:text=Now%2C%20researchers%20have%20successfully%20created,tubule%20formation%20after%2028%20days. 

Heidt, Amanda. “Scientists Grow Humanized Kidneys in Pig Embryos.” ScienceNews. 7 Sept. 2023. www.sciencenews.org/article/grow-human-kidney-pig-embryo. 

“Organ Donation Statistics.” Health Resources & Services Administration. www.organdonor.gov/learn/organ-donation-statistics. 

Redman, Melody, et al. “What is CRISPR/Cas9?” National Library of Medicine. 8 April.  2016. www.ncbi.nlm.nih.gov/pmc/articles/PMC4975809/

Romito, Antonio and Gilda Cobellis. “Pluripotent Stem Cells: Current Understanding and Future Directions.”National Library of Medicine. 20 Dec. 2015. www.ncbi.nlm.nih.gov/pmc/articles/PMC4699068/. 

 Le Page, Michael. “What is a Chimera?” NewsScientist. www.newscientist.com/question/what-is-a-chimera/