Friday, June 21, 2013

Human organs 'could be grown in animals within a year'

http://www.telegraph.co.uk/science/science-news/10132347/Human-organs-could-be-grown-in-animals-within-a-year.html


Human organs 'could be grown in animals within a year'
Japanese scientists are expecting to be granted approval to grow human organs in animals and then harvest them for transplant within the next year.
Surgeons perform a transplant as it was announced today that Japanese scientists are expecting to be granted approval to grow human organs in animals and then harvest them for transplant within the next year Photo: Alamy

By Julian Ryall, Tokyo 2:41PM BST 20 Jun 2013

  A panel of scientists and legal experts appointed by the government has drawn up a recommendation that will form the basis of new guidelines for Japan's world­leading embryonic research.
There is widespread support in Japan for research that has raised red flags in other countries. Scientists plan to introduce a human stem cell into the embryo of an animal – most likely a pig – to create what is termed a "chimeric embryo" that can be implanted into an animal's womb.
That will then grow into a perfect human organ, a kidney or even a heart, as the host animal matures.

When the adult creature is slaughtered, the organ will then be harvested and transplanted into a human with a malfunctioning organ.
"This recommendation is a very important step forward and one that has taken us three years to achieve," Professor Hiromitsu Nakauchi, head of the centre for stem cell biology and regenerative medicine at the University of Tokyo, told The Daily Telegraph.
Prof Nakauchi's team have already succeeded in injecting stem cells from rats into the embryos of mice that had been genetically altered.
"We can apply the same principles to human stem cells and pigs, although the guidelines have not permitted us to do this yet," he said.
At present, the Japanese guidelines permit scientists to develop chimeric embryos in laboratory conditions for a maximum of 14 days, but the next stage in the process – the embryos being implanted into an animal's womb – is prohibited.
As soon as government officials agree on the details of the revised guidelines – a process that is expected to take 12 months – Prof Nakauchi believes the first pig carrying a human organ can be produced "quite quickly, because the technique has been established already."
The scientists plan to initially breed a pig with a human pancreas as it is a relatively easy organ to create, Prof. Nakauchi said, and perfecting the technique will bring relief to millions of people with diabetes.
Creating kidneys and a human heart will be far more complicated, he said, but are feasible. He suggested that practical use for the organs may be as little as five years away.
Eventually, he hopes to be able to have numerous human organs within each donor animal that can be harvested all at the same time.
© Copyright of Telegraph Media Group Limited 2013 

Monday, April 15, 2013

Researchers develop implantable, bioengineered rat kidney (w/ video)

http://medicalxpress.com/news/2013-04-implantable-bioengineered-rat-kidney-video.html



Researchers develop implantable, bioengineered rat kidney (w/ video)

April 14th, 2013 in Medical research 
Mass. General team develops implantable, bioengineered rat kidney

Removal of all living cells from a rat kidney leaves a collagen scaffolding, ready for repopulation with new kidney and vascular cells. Credit: Massachusetts General Hospital Center for Regenerative Medicine.
Bioengineered rat kidneys developed by Massachusetts General Hospital (MGH) investigators successfully produced urine both in a laboratory apparatus and after being transplanted into living animals. In their report, receiving advance online publication in Nature Medicine, the research team describes building functional replacement kidneys on the structure of donor organs from which living cells had been stripped, an approach previously used to create bioartificial hearts, lungs and livers.
"What is unique about this approach is that the native organ's architecture is preserved, so that the resulting graft can be transplanted just like a  and connected to the recipient's vascular and urinary systems," says Harald Ott, MD, PhD, of the MGH Center for Regenerative Medicine, senior author of the Nature Medicine article. "If this technology can be scaled to human-sized grafts, patients suffering from  who are currently waiting for donor kidneys or who are not  could theoretically receive new organs derived from their own ."
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Around 18,000 kidney transplants are performed in the U.S. each year, but 100,000 Americans with end-stage  are still waiting for a . Even those fortunate enough to receive a transplant face a lifetime of , which pose many health risks and cannot totally eliminate the incidence of eventual .
The approach used in this study to engineer donor organs, based on a technology that Ott discovered as a research fellow at the University of Minnesota, involves stripping the living cells from a donor organ with a detergent solution and then repopulating the collagen scaffold that remains with the appropriate cell type – in this instance  to replace the lining of the vascular system and kidney cells from newborn rats. The research team first decellularized rat kidneys to confirm that the organ's complex structures would be preserved. They also showed the technique worked on a larger scale by stripping cells from pig and human kidneys.
Making sure the appropriate cells were seeded into the correct portions of the collagen scaffold required delivering vascular cells through the renal artery and  through the ureter. Precisely adjusting the pressures of the solutions enabled the cells to be dispersed throughout the whole organs, which were then cultured in a bioreactor for up to 12 days. The researchers first tested the repopulated organs in a device that passed blood through its vascular system and drained off any urine, which revealed evidence of limited filtering of blood, molecular activity and urine production.
Mass. General team develops implantable, bioengineered rat kidney
This is a previously decellularized rat kidney after reseeding with endothelial cells, to repopulate the organ's vascular system, and neonatal kidney cells. Credit: Massachusetts General Hospital Center for Regenerative Medicine
Bioengineered kidneys transplanted into living rats from which one kidney had been removed began producing urine as soon as the blood supply was restored, with no evidence of bleeding or clot formation. The overall function of the regenerated organs was significantly reduced compared with that of normal, healthy kidneys, something the researchers believe may be attributed to the immaturity of the neonatal cells used to repopulate the scaffolding.
"Further refinement of the cell types used for seeding and additional maturation in culture may allow us to achieve a more functional organ," says Ott. "Based on this inital proof of principle, we hope that bioengineered kidneys will someday be able to fully replace kidney function just as donor kidneys do. In an ideal world, such grafts could be produced 'on demand" from a patient's own cells, helping us overcome both the organ shortage and the need for chronic immunosuppression. We're now investigating methods of deriving the necessary cell types from patient-derived cells and refining the cell-seeding and organ culture methods to handle human-sized organs."
Ott's team focuses on the regeneration of hearts, lungs, kidneys and grafts made of composite tissues, while other teams – including one from the MGH Center for Engineering in Medicine – are using the decellularization technique to develop replacement livers. Lead author of the Nature Medicine paper is Jeremy Song, MGH Center for Regenerative Medicine; additional co-authors are Jacques Guyette, PhD, Sarah Gilpin, PhD, Gabriel Gonzalez, PhD, and Joseph Vacanti, MD, all of the MGH Center for Regenerative Medicine. The study was supported by National Institute of Health Director's New Innovator Award DP2 OD008749-01.
More information: dx.doi.org/10.1038/nm.3154
Provided by Massachusetts General Hospital
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