Actually it is
surprising just how far along this all is.
Some pretty significant milestones have been reached to the point it may
well be down to biochemistry. This is
something we can be pleased about.
Expanding budgets can well deliver us real success in a decade and this
is extraordinary news.
It means of
course that simple heart replacement becomes a viable option in the face of a
failing circulatory system. It also
means that vein and artery replacement will become an important protocol.
Of course none
of this actually extends ones biological lifespan but it makes it plausible
that one can actually reach it. All this
technology is arriving rather quickly and I expect that the following two
decades will allow total replacement of all tissues including parts of the
brain. Thus by 2035, it will be possible
to sustain oneself in one’s prime to the end of biological lifespan.
I do then
anticipate that we will have also long since learned how to reverse cellular
aging itself to allow for very long lifespans.
Thus as humanity actually reaches its peak population our lifespans will
extend that population into the centuries ahead. We have plenty of work to do anyway.
Bioengineer: the
heart is one of the easiest organs to bioprint, we'll do it in a decade
A team of cardiovascular scientists has announced it
will be able to 3D print a whole heart from the recipients' own cells within a
decade.
"America put a man on the Moon in less than a
decade. I said a full decade to provide some wiggle room," Stuart K
Williams told Wired.co.uk.
Williams is heading up the hugely ambitious project
as executive and scientific director of the Cardiovascular
Innovation Institute at the
University of Louisville. Throughout his prestigious career spanning four
decades he has focused on researching surgical devices and bioengineering, and
the idea for printing the heart whole from scratch was inspired by the work of
one of the pioneers in both these fields -- Charles Lindbergh. Lindbergh might
be best known for flying solo across the Atlantic and for the Crime of the
Century (when his infant son was kidnapped and murdered) but he also created a
glass perfusion pump with Alexia Carrel that would keep the human heart alive
outside the body, paving the way for heart surgery. The pair also discussed
regenerative medicine in their book The Culture of Organs.
"For bioprinting it is the end of the beginning
as bioprinted structures are now under intense study by biologists"
Some 70 plus years after the publication of that
book, Williams' predictions shouldn't sound all that incredulous, but he admits
it's been met with resistance. "That's why we are excited," he tells
Wired.co.uk. "Funding is very limited as this is a new area. But as
bioprinting successes occur the interest will increase and then funding -- so
many breakthroughs have occurred in this way with a new untested idea that is
moved forward with limited resources.
"For bioprinting it is the end of the beginning
as bioprinted structures are now under intense study by biologists."
Williams says he and his team of more than 20 have
already bioengineered a coronary artery and printed the smallest blood vessels
in the heart used in microcirculation. "These studies have reached the
advanced preclinical stage showing printed blood vessels will reconnect with
the recipient tissue creating new blood flow in the printed tissue."
The team has also worked on other methods of
bioengineering tissue, including electrospinning for the creation of large
blood vessel scaffolds that can then be joined with bioprinted microvessels.
But why print the parts, when you can print the
whole in one go? We shouldn't just be able to repair the heart using
bioengineering, but replace it.
The Cardiovascular Innovation Institute is now
developing bespoke 3D printers for the job with a team of engineers and
vascular biologists -- "if you do not understand the biology, you solve
only half the problem" explains Williams. Though for now those printers
are focusing on replicating the parts, the plan is to print the whole in one go
in just three hours, with a further week needed for it to mature outside of the
body. Certain parts will need to be printed and assembled beforehand, including
the valves and the biggest blood vessels. "Final construction will then be
achieved by bioprinting and strategic placement of the valves and big
vessels," says Williams, who asserts that they are "on schedule"
to build the bioficial heart within the decade marker. The bioprinter he says
will be capable of achieving all the forementioned work, is under construction
now in Louisville.
"Dare I say the heart is one of the easiest to
bioprint? It's just a pump with tubes you need to connect"
Giving a simplified breakdown of the process, he
explains: "a patient enters the operating room and tissue is removed (we
think fat is the best source) and regenerative cells isolated. The cells are
then mixed with solutions that contain extracellular matrix molecules and other
factors and placed in the bioprinter. The bioprinter then prints the
heart."
Bioengineers have already 3D printed a tiny functioning liver, but the problem is keeping it alive. The liver,
for instance, was just a millimetre thick and four millimetres wide, and
survived only five days.
The key to Williams' heart surviving could be in
encouraging the natural self-organising of cells in that heart, that drives a
process called inosculation he describes as the "knitting together"
of cells. It's how surgeons explain the connection made between skin grafts and
tissue. "The bioprinted vessels [will] inosculate with the recipient blood
vessels, and blood flows into the printed vessels," says Williams. This is
how those various parts of the whole will stitch together, with microvessels
connecting the parts of the whole to get the nutrients where they need to be.
Kevin Shakesheff, director of the Wolfson Centre for
Stem Cells, Tissue Engineering and Modelling and the UK Regenerative Medicine
Platform Hub in Acellular Technologies, is in agreement that these final stages
of the process will be integral to the group's success. "The foundations
of the project are solid but there needs to be rapid progress in printing of
such a complex tissues, in creating enough cells to print and in the maturation
of the final tissue -- the fine connections between cells that make a heart
functional." Nevertheless, Shakesheff told Wired.co.uk he does
believe that a printed heart in ten years is possible.
Compared to something like the liver, which relies
on complex cellular processes for filtration, Williams believes starting with
3D printing a whole heart is actually a bit of a no-brainer. "Dare I say
the heart is one of the easiest to bioprint? It's just a pump with tubes you
need to connect. A kidney is much more complex. And then the
brain…"
He is confident that the increased interest in the
field will naturally support projects such as these as the field expands -- not
least because of all the related technologies that will offshoot from the
research. And this is what will keep them on schedule.
"There is great interest and support [because]
everyone understands this technology will lead to ancillary discoveries and new
therapies to treat just part of the heart or part of the circulatory
system." Of course, he admits, the early versions will be expensive --
something flagged up by skeptics of the technology. But that's the same for any
groundbreaking technology.
"The big issue is money," Shakesheff tells
Wired.co.uk. "To do this in ten years needs a massive amount of
funding and the money needs to be spent properly and quickly."
We've already seen the cost of consumer-ready 3D
printers plummet, and with the infinite possibilities provided by a biological
3D printer, it's only a matter of time before the latter follows suit.
One day, the bioprinter might be as ubiquiotus in
hospitals as an X-ray machine.
Update: This article was amended on 22
November to include additional comment from professor Kevin Shakesheff.
No comments:
Post a Comment