Lab grown embryo raises new possibilities for regenerative medicine

Scientists have grown embryo-like structures in the laboratory that produced human blood cells, raising new possibilities for regenerative medicine.

The discovery could one day enable patients who need bone marrow transplants to receive cells grown from their own tissue, avoiding compatibility issues.

The embryo models were made from stem cells, without using eggs or sperm, providing new insight into early human development.

Researchers at the University of Cambridge’s Gurdon Institute developed the structures, which self-organised to produce blood cells by day 13.

Dr Jitesh Neupane is a researcher at the Gurdon Institute and first author of the study.

Neupane said: “It was an exciting moment when the blood-red colour appeared in the dish – it was visible even to the naked eye.”

The team is using the model system to explore the earliest stages of heart and blood development.

The human stem cells used to create the embryo-like structures can be derived from any cell in the body, meaning the approach could produce blood fully compatible with a patient’s immune system.

Unlike other laboratory methods that rely on adding protein cocktails, this model mimics natural developmental processes, allowing the structures to self-organise and drive cell formation.

The scientists used human stem cells to replicate some of the cells and structures that would normally appear during the third and fourth week of pregnancy.

The model was specifically designed to exclude the tissues that form the placenta and yolk sac in natural embryos, meaning it lacked the potential to develop into a foetus and did not form brain tissue.

Under the microscope, the three-dimensional structures began to self-organise by day two, forming three germ layers – the ectoderm, mesoderm and endoderm – which form the foundations of the human body.

By day eight, beating heart cells had formed – the cells that eventually give rise to the heart in a developing embryo. By day 13, red patches of blood were visible.

Blood stem cells taken from the model were shown to differentiate into various blood cell types, including oxygen-carrying red blood cells and white blood cells vital to the immune system.

This ability to mature into different cell types highlights their potential for future treatments.