Stem-cell-based embryo model mimics human blood development

A stem-cell-based embryo model (SCBEM) capable of producing human blood stem cells has been created in the lab, mimicking early embryonic development.

Scientists from the University of Cambridge have created the SCBEM – which they call a 'hematoid' – from human embryonic stem cells. It demonstrates features of early human development, including the production of red blood cells.

'It was an exciting moment when the blood red colour appeared in the dish – it was visible even to the naked eye,' said Dr Jitesh Neupane, co-first author of the study, published in Cell Reports. Dr Neupane previously discussed his work in this area in 2023, at the annual meeting of the International Society for Stem Cell Research (see BioNews 1195).

Other methods of generating blood cells in the laboratory have required extra proteins to direct cell differentiation (see BioNews 1258). Hematoids emulate natural developmental processes, as they form self-organising structures to support the growth of blood cells.

'Hematoids capture the second wave of blood development that can give rise to specialised immune cells or adaptive lymphoid cells, like T cells, opening up exciting avenues for their use in modelling healthy and cancerous blood development,' said co-first author Dr Geraldine Jowett.

The generation of hematoids could help to advance understanding of blood cell formation, and of blood-associated disorders such as leukaemia. Human blood stem cells are specialised cells that can develop into multiple blood cell types. In future, hematoids could be developed from adult body cells, opening up possibilities for generating a patient's own blood stem cells for transplantation.

'The ability to produce human blood cells in the lab marks a significant step towards future regenerative therapies – which use a patient's own cells to repair and regenerate damaged tissues,' said senior author Professor Azim Surani.

As well as allowing researchers to visualise and characterise blood cell production, hematoids also offer a window into understanding early human development. The stages at which blood cells are produced in natural human embryos are not generally amenable to study or visualisation as they occur after implantation in the womb, around weeks three and four of pregnancy.

Hematoids do not contain tissues that produce the placenta and yolk sac, required for normal embryo development. Research involving hematoids, like all UK research involving SCBEMs that contain human cells, is governed by the UK's Code of Practice for the Generation and Use of Human Stem-Cell-Based Embryo Models (see BioNews 1246a and 1246b).