Science & technology

Scientists Grow Human Hearts in Pig Embryos for 21 Days

JUN 13 2025·Updated JUN 15 2025

Story

Above: Oocytes prepared for genetic modification injection at Revivicor Labs in Virginia on Nov. 22, 2024. Image credit: ANDREW CABALLERO-REYNOLDS/AFP/Getty Images

The Facts

Researchers at the Guangzhou Institutes of Biomedicine and Health successfully grew beating human hearts inside pig embryos for 21 days, marking the first time human heart cells have survived in pig embryos for this duration.
Nature
Slashdot
The hybrid embryos contained fingertip-sized hearts that began beating after human stem cells were reprogrammed to survive in pigs and introduced into pig embryos with two heart development genes knocked out.
Nature
Slashdot
The research team, led by Lai Liangxue, used luminescent biomarkers to tag human cells, making them visible as glowing components within the developing pig hearts during the 21-day survival period. To create heart organs suitable for transplantation, researchers must construct them entirely from human cells — it's unclear to what extent the hearts in this study were composed of human cells.
Nature
Slashdot
Lai and his colleagues presented the findings — which haven't been peer-reviewed — this week at the International Society for Stem Cell Research annual meeting in Hong Kong.
Nature
Slashdot
Previous xenotransplantation attempts — the transplantation of cells, tissues, or organs between species — have shown mixed results, with David Bennett surviving 60 days after receiving a genetically modified pig heart in 2022, while Lawrence Faucette lived 40 days before rejection occurred in 2023. Pigs are considered promising donor animals due to the size and anatomical similarity of their organs to those of humans.
Medschool
NCBI
Nature
More than 100,000 Americans are currently on organ transplant waiting lists, with an estimated 17 people dying each day while waiting. These persistent shortages have led researchers to explore human-animal chimeras as a potential source of transplantable organs.
nytimes
guardian
Science News

Sources Split

LEFT

CENTER

RIGHT

ESTAB
CRIT

CENTER

PRO
ESTAB

The Spin

Techno-optimist narrative

This breakthrough represents a monumental leap toward solving the organ shortage crisis that kills thousands annually. Growing human hearts in pig embryos for three weeks proves the concept works and brings hope to desperate patients on transplant lists. The technology could revolutionize medicine by providing unlimited organ supplies.

Singularity Hub

Techno-skeptic narrative

These experiments raise serious ethical concerns about creating human-animal hybrids and exploiting animals for human benefit. The research involves genetic manipulation of sentient beings and could lead to unforeseen consequences, including potential viral transmission between species. Playing God with nature's boundaries demands extreme caution.

BBC Science Focus Magazine

guardian

Metaculus Prediction

Editor's Note

This story currently has limited coverage. We will continue to monitor all major outlets and update our reporting as additional information becomes available.