OpenAI CEO Sam Altman has invested nearly $180 million (over ₹1,740 crore) in Retro Biosciences, a startup aiming to slow ageing and fight diseases like Alzheimer's and cancer. The firm is trying to reset ageing cells into a younger biological state without fully converting them into stem cells. Retro is collaborating with OpenAI for an AI model called GPT-4b micro.