Reacción a "Reactions to study in which 'mini-brains' derived from human cells were implanted into newborn rats"

This study from Stanford University is very interesting. It is not the first time that human tissues manufactured in the laboratory have been integrated into adult animals, rats or athymic mice (i.e. immunodeficient, unable to reject the tissues and cells of another species). This has been done numerous times with different tissues (muscle, skin, blood, nerve tissue, etc.). But yes, to my knowledge, this is the first case of a human organoid brain tissue transplanted into the brain of a newborn rat, with its brain in full development, which shows not only that it is not rejected but that it integrates with the rat's own brain functions, interconnecting with each other (the authors activate the human cells by rubbing the rat's whiskers, demonstrating that these human brain organoid cells have managed to connect to this somatosensory circuit), and illustrating a new way of looking at functional deficits of brain tissue in organoids from patients with neurological disease (the authors demonstrate this with organoids derived from cells of patients with Timothy syndrome, a rare disorder with multiple organ involvement and cardiac impairment as a hallmark symptom).

It is a surprising experiment and a very significant breakthrough, combining laboratory studies (organoids) with animal studies (transplantation of organoids into the brains of athymic rats). This experiment also raises relevant ethical aspects of this research, which will have to be taken into account and discussed in future similar procedures, as brains are somehow generated in these animals that are partially hybrids between neurons from the rat and neurons from the patient used in the process.