This week, Luke rolls up his sleeves to tackle a listener request from Danny and Caroline. Caroline’s living with osteoarthritis, so stem cells seemed like just the ticket for discussion. We start with the basics: stem cells are the body’s precursors, the young all-rounders that can grow into brain neurons, cartilage-makers, or insulin-producing pancreatic cells. In theory, they can be coaxed into replacing damaged tissue—making them, as Luke puts it, a sort of “living drug.” The story begins with leukemia treatment, where donor bone marrow can regrow an entire immune system, sometimes with cure rates of up to 90%. We also meet “bubble baby disease” (SCID), where stem cells can give a child the immune system they never had. From fertilised eggs (the ultimate stem cell) to Nobel prize-winning frog cloning, Luke traces the remarkable science that shows every cell in your body carries the full blueprint for making you. He explains the controversies over embryonic stem cell research, the promise of adult-derived mesenchymal stem cells, and the exciting rise of induced pluripotent stem cells (iPSCs) which are adult cells reprogrammed to behave like embryonic ones. No FDA-approved stem-cell therapies for major diseases just yet, but Parkinson’s trials are showing some glimmers of hope. For osteoarthritis, Luke’s verdict is: stem cells “might help a bit,” but the science isn’t slam-dunk yet, especially when you’re injecting cells into a joint that never stops moving. Other targets, like heart and lung disease, may turn out to be better bets. The market for stem-cell therapies could hit a billion dollars by 2031, so expect plenty of hype and, hopefully, plenty of progress. In the meantime, we’ve got real breakthroughs, fascinating biology, and Luke’s usual mix of optimism and caution. Got a topic you’d like Luke to tackle? Email [email protected] and your idea might make it onto the show.

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“What did the council decide on item 42?” — answered with the speaker and the moment.