As regenerative medicine and stem cell technologies continue to progress, so the list of tissues and organs that can be grown from scratch – and potentially replaced – continues to grow. In the past few years, researchers have used stem cells to grow windpipes, bladders, urethras and vaginas in the lab, and, in some cases, successfully transplanted them into patients.
Others are making progress in growing liver and heart tissue; one team in London is busy growing blood vessels, noses and ears; and some have even managed to grow tiny chunks of brain tissue, the most complex of all the tissues in the human body. Now, researchers in Germany report that they have grown complete spinal cords from embryonic stem cells.
Most efforts to grow tissues and organs rely on biodegradable scaffolds. When ‘seeded’ with a patient’s stem cells, these scaffolds provide a surface for the cells to latch on to and provide them with nutrients. The scaffold delivers the signals needed for the stem cells to differentiate along the correct path, and its structure coaxes them to form tissue of the right shape.
Nervous tissue is extremely complex, however. It starts off as a flat sheet of cells on the top surface of the embryo, called the neural plate, which, through a series of elaborate deformations, buckles and folds in on itself to form a hollow tube. One end of this neural tube will eventually form the brain, and the other the spinal cord. This complexity makes scaffolds unsuitable for growing nervous tissue, as they cannot be manufactured in the intricate shapes needed.
Andrea Meinhardt of the Dresden University of Technology and her colleagues therefore exploited a property of stem cells known as self-directed morphogenesis, first discovered by the late Yoshiki Sasai. About 10 years ago, Sasai and his colleagues developed a method for growing embryonic stem cells in three-dimensional suspension, and found that cells grown in this way can, when fed the right combination of signalling molecules, go through the motions of development and organize themselves to form complex tissues such as eyes, glands and bits of brain.
Meinhardt and her colleagues used a variation of Sasai’s technique, and embedded single-cell suspensions of mouse embryonic stem cells within a three-dimensional nutrient gel on Petri dishes. When left untreated, the cells begin to differentiate into immature neurons, giving rise to spherical structures containing immature cells resembling those found in the neural plate. Read the rest of this entry »
Randal Koene is recruiting top neuroscientists to help him make humans live forever
By mapping the brain, reducing its activity to computations, and reproducing those computations in code, humans could live indefinitely…
On stage, a speaker with a shaved head and a thick, black beard held forth on DIY sensory augmentation. A group called Science for the Masses, he said, was developing a pill that would soon allow humans to perceive the near-infrared spectrum. He personally had implanted tiny magnets into his outer ears so that he could listen to music converted into vibrations by a magnetic coil attached to his phone.
The concept of brain emulation has a long, colorful history in science fiction, but it’s also deeply rooted in computer science.
None of this seemed particularly ambitious, however, compared with the claim soon to follow. In the back of the audience, carefully reviewing his notes, sat Randal Koene, a bespectacled neuroscientist wearing black cargo pants, a black T-shirt showing a brain on a laptop screen, and a pair of black, shiny boots. Koene had come to explain to the assembled crowd how to live forever. ”As a species, we really only inhabit a small sliver of time and space,”Koene said when he took the stage. ”We want a species that can be effective and influential and creative in a much larger sphere.”
Koene’s solution was straightforward: He planned to upload his brain to a computer. Read the rest of this entry »
The narrator talks fast. I like that. Look for the phrase “Hormonal Rodeo”.
Being a teenager is hard. Especially when hormones play their part in wreaking havoc on the teenage body and brain. In this episode, Hank explains what is happening to the during the angsty-time.