It seems that this is a week for announcing significant progress in tissue engineering. You might recall that one of the groups involved in recellularization research transplanted a trachea into a human recipient a couple of years ago. The organ was from a donor, stripped of all its cells, and the remaining natural scaffold of the extracellular matrix repopulated with cells from the recipient. The end result was a transplanted organ that would not be rejected by the immune system. The same researchers have now gone one step further and successfully transplanted an entirely synthetic trachea grown from the patient's cells on an artificial scaffold - no donor organ required.

Surgeons have performed the first transplant operation using an organ wholly grown in a laboratory to give a man a new windpipe. The 36-year-old is recovering after surgeons implanted the world's first wholly lab-grown organ into his body.

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Professor Paolo Macchiarini, a Spanish expert in regenerative medicine who led the groundbreaking operation, designed the Y-shaped synthetic trachea scaffold with Professor Alexander Seifalian, from University College London. The Y-shaped structure was made from a plastic-like "nanocomposite" polymer material consisting of microscopic building blocks. Two days after stem cells were placed into the scaffold they had grown into tracheal cells ready for transplantation. Since the organ was built from cells originating from the patient, there was no risk of it being rejected by his immune system.

In conjunction with lines of research like organ printing, this pace of work bodes well for the 2030s as a time in which failing or badly injured organs are no longer automatically fatal or the cause of lifelong disability for the young. There is still the question of how best to take advantage of this for the old, however: the frailty that comes with aging brings with it a much lower survival rate and success rate for major surgery - and any significant transplant is major surgery. Regrowth of organs alone is not the way to greatly extend the maximum human lifespan on a timescale that matters. Other technologies are needed as well:

There are many whole-body, multi-organ, or regional biochemical feedback and control loops in the body. There are types of age-related damage that involve the intracellular accumulation of biochemical junk - simply replacing cells doesn't get rid of that. If your only tool is bioprinting (which won't be the case, but let us think inside the box for a while here), then the solution to these problems starts to look like replacing more of the body at one time.

You can't just replace the brain, of course, which remains an important limiting factor and the real driving need for in situ repair technologies that operate at the level of cells, buildup of protein aggregates, and broken cellular machinery.