Lab-grown kidney appears functional in animals

We are getting better in optimizing the compatibility of organs, and have thereby made transplantations feasible, but the lack of available donors is a huge problem. Attempts are being made to get people signed up for donor programs, but this is not enough to cover the gap. Novel attempts are being made to grow artificial organs in the lab. While it has been possible to grow tissues for quite some time, creating a fully-fledged organ suitable for transplantation has so far been impossible. Scientists from the UK and Italy have however succeeded in getting a functional lab-grown kidney transplanted in an animal.

Development

Growing a functional kidney in the lab is not an easy feat, especially because custom-made tissues refuse to create their own blood vessel network, which the kidney obviously needs to filter the blood, and for its own nutrients and oxygen. Your editor has experience with doing this kind of research, and even collaborated with the UK scientists in an earlier stage in order to make this concept functional. The technique is based on getting kidney cells from a mouse embryo, which means the cells are still in an early developmental phase, allowing for greater flexibility. 

Organoid

Incubation of such cells leads to the formation of kidney tissues, much in the same way it does when the mouse embryo would have been left alone. Once the clumps of cells reached a certain size and developmental stage, the scientists 'bathed' them in a solution containing VEGF molecules. This particular substance functions in the body by 'calling' for blood vessel growth. After the bathing procedure, the organoids were transplanted into rats. Even though the tissue is of mouse origin, previous research already showed the embryonic kidneys of mice and rats are exchangeable. In order to further stimulate the development of a blood vessel network after transplantation, the scientists injected the rats with an extra dose of VEGF.

Small, bean-sized ordinary kidneys coming from either a rat or a mouse.

Function

After implanting, the researchers noted that blood vessels started to appear within days, and that the transplanted kidneys showed structures typical for the development of kidneys. Also functionally the kidneys appeared to do their jobs: when a light-emitting version of the protein albumin was injected into the bloodstream, the scientists showed that the kidneys were able to filter it properly, much in the same way an ordinary kidney does. This means the transplant does not only look like a kidney, it also functions like a kidney.

Outlook

The newly developed technique solves several issues regarding lab-grown organs. By being able to grow a vascularised kidney, meaning it contains blood vessels, and also getting it ready for animal transplantation, the scientists made a huge step forward in the development of custom-made organs ready for clinical use. Obviously, the technique needs to be refined before any use in human beings can be considered. In addition, it would be necessary to work with human embryos, which is considered to be unethical.