[Source: Nature]
[Source: Nature]
Imagine a future in which no one died anymore waiting for an organ. Harvard researchers have taken a major step toward that reality by not only growing an organ in the lab, already a common practice, but transplanting it into an animal and showing that it works. They did it with a regrown kidney transplanted into a mouse, but say their method has the potential to be used with all sorts of organs.

The first step in the procedure involved taking a donor rat kidney and using a detergent to wash away its functional cells. What remained was the extracellular matrix scaffold, a protein structure that preserved the kidney’s underlying three-dimensional architecture. They then placed kidney and blood vessel cells taken from newborn rats onto the scaffold, using pressure generated from a vacuum to move the cells to the right areas. The “seeded” organ was then placed in a bioreactor to allow the cells to grow up and form a healthy, functional kidney.

Cells from a cadaver kidney (left) are first washed of its cells, leaving a protein scaffold (right). [Source: Nature Medicine]
Cells from a cadaver kidney (left) are first washed of its cells, leaving a protein scaffold (right). [Source: Nature Medicine]
The researchers first checked to see if it functioned the way it was supposed to in the lab. It performed as a normal kidney should, reabsorbing nutrients and sugar and producing urine. They then transplanted the lab-grown kidney into a live rat. Compared with a kidney gotten from a cadaver rat – the experimental equivalent of a donated kidney – the lab-grown kidney fell short. It wasn’t able to process substances quite as well as the cadaver kidney. Despite this, it was able to produce urine. The researchers think that allowing the kidney more time in the bioreactor to mature may improve its performance.

The study was published in the April 14 issue of Nature Medicine.

Although it might not work as well as a cadaver kidney, the fact that it generated urine in a breathing, eating rat is a major proof-of-principle. Harald Ott, the study’s senior author, plans to optimize the cell-seeding procedures to improve performance. And as he states in the video below, they’re not just thinking about kidneys: “The reason I’m most excited about this recent publication is because it shows the platform character of this technology. The technology can be applied to any tissue, any organ that can be perfused by its own vascular system.”

[Source: NatureVideoChannel via YouTube]

Almost a million people in the United States are living with end-stage kidney disease. Another 100,000 are diagnosed every year. As yet there is no way to restore a failed kidney to good health. Hemodialysis is the most common treatment, but while dialysis prolongs a person’s life, it burdens the patient with time lost, limits on how much fluid they can drink, and often low energy. The only curative treatment is receiving a new kidney. Approximately 100,000 people in the US are waiting for a new kidney, but each year only 18,000 kidney transplants are performed here. Average wait time for a new kidney is three to five years. During that time, 10 to 15 percent of patients die.

The day this technology impacts humans is still a long way off. When it does, however, it will bring those in need to the front of very long waiting lists.

Peter Murray was born in Boston in 1973. He earned a PhD in neuroscience at the University of Maryland, Baltimore studying gene expression in the neocortex. Following his dissertation work he spent three years as a post-doctoral fellow at the same university studying brain mechanisms of pain and motor control. He completed a collection of short stories in 2010 and has been writing for Singula...
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