Scientists at the University of Cambridge have created a lab-grown human embryo-like structure that replicates early human development, including the production of blood stem cells. The breakthrough could help researchers produce blood stem cells for transplants, screen drugs, and understand blood disorders such as leukaemia.
Named 'hematoids', these embryo-like structures start producing blood after around two weeks of development in the lab, mimicking the natural process in human embryos. Dr Jitesh Neupane, a researcher at the University of Cambridge’s Gurdon Institute and first author of the study published in Cell Reports, said: 'It was an exciting moment when the blood red colour appeared in the dish – it was visible even to the naked eye.'
Unlike real embryos, hematoids lack several embryonic tissues and the supporting yolk sac and placenta needed for further development. However, they capture the second wave of blood development that can give rise to specialised immune cells, such as T cells. Dr Geraldine Jowett, co-first author, noted this opens avenues for modelling healthy and cancerous blood development.
The human stem cells used to create hematoids can be derived from any cell in the body, offering potential for patient-compatible blood. This method mimics natural development without requiring extra proteins for stem cell growth. By day eight, beating heart cells had formed, and by day thirteen, red patches of blood were visible. The blood cells developed to a stage corresponding to week four to five of human embryonic development, a period that cannot be directly observed in real embryos.
