A new way to grow blood in a laboratory
A new method of producing red blood cells from stem cells.
A new way to produce transfusable blood in the laboratory is being developed by UK researchers. Every day, a country the size of ours gets through about 2 tonnes of donated blood. At the moment, all of it needs to come out of someone else’s arm. But now researchers have found a way to grow more blood cells from donated blood that could be used to supplement traditional supplies. Cedric Ghevaert, from Cambridge University’s Department of Haematology, is one of the team behind a trial to put these lab-grown blood cells through their paces in real patients…
Cedric - What we have to do is to take stem cells that are present in anyone's blood, including donated blood, and we put them in special solutions with growth factors. It's a bit like growing plants and feeding your plants. And then over a period of 20 days thereabout, they will multiply, but they will also change their nature from a stem cell to a mature red cell.
Chris - And do they, to all intents and purposes, look like, smell like, taste like, and work like a normal red blood cell?
Cedric- Absolutely. We put them through their paces in laboratories through a series of tests before the clinical trial to make sure they absolutely behaved the same way as a donor derived red blood cell.
Chris - And you are obviously sufficiently happy that this works well enough and safely enough. You're now going to put these into real patients.
Cedric - We are actually starting very small with healthy volunteers and we only produce two teaspoons of those red cells to then do this clinical trial that is currently ongoing. We want to check whether these labs produce red cells that last longer in a circulation compared to donor derived red cells.
Chris - Why should they?
Cedric - It's simply because donated blood contains red cells that are newly born, but also red cells that have been circulated for two, three months that are very old and they will disappear from circulation quite promptly. Whereas the cells that are being produced in the laboratory all are born at the same time. So they're all young, so they should survive in a circulation average much longer than a donated blood.
Chris - These cells that we're talking about though they are fractions of a millimeter across. How on earth are you going to track a teaspoon full of those over time to work out how long they are there?
Cedric - We label them with a very, very small amount of radioactivity before we reinject them. And then we take a series of blood samples from the volunteers taking part in a trial who are receiving those blood cells. And then we use a machine to detect these very, very small amounts of radioactivity. Over time that radioactivity will fade because those red cells will gradually disappear from circulation. And as we measured the fade, that gives us an idea of how long those cells are surviving circulation.
Chris - And the advantage would be, if you have cells that live longer, a patient who needs a blood donation wouldn't need their blood transfusion as frequently because what you're giving them would last longer.
Cedric - Absolutely. This is absolutely transformational for patients who have got genetic disorders whose life really depends on being transfused regularly. At the moment they're transfused every two to three weeks. We could potentially transfuse them every six to eight weeks.
Chris - You're obviously comfortable that these cells are safe. One always worries when you take stem cells and then you grow them and stimulate them in the lab that they then turn into things that you would rather they didn't, like cancer cells for example. What checks and balances are there to make sure that can't happen?
Cedric - One of the big advantages is that red cells don't contain a nucleus, so they can't multiply, they can't become cancerous
Chris - But the stem cells can
Cedric - The stem cells can, but the purification of the product that we make in the lab is the last step and it takes away any cell that contains a nucleus.
Chris - So it's just the blood that's left over. So it should, in theory, be very safe. How much can you make? I know you're saying in this case that it's gonna be a couple of teaspoons full for the purpose of experimentation, but if this is gonna be practically used, you're gonna have to make a lot of blood. How scalable is this?
Cedric - It is scalable. Absolutely. And manufacturing a large quantity of cells is something that has really taken off in the last decade. But in particular, the pandemic has shown us how much more we can scale cell cultures. In this case it was to produce the vaccine, but some of those technologies are directly applicable to what we want to do with the red blood cells.
