In Canada and around the world, a lot of people need a new kidney.
In fact, nearly 80 per cent of Canadians waiting for an organ donation are looking for a kidney, according to the Kidney Foundation of Canada, and donor rates have dropped in recent years to only 14-17 donors per million people.
Well, a new breakthrough might offer some hope in the long term. For the first time, researchers have "grown" a kidney in a lab and successfully transplanted it into a lab rat.
Scientists at Massachusetts General Hospital in Boston took the kidney of a recently dead rat and used detergent to strip away the cells, leaving behind connective tissues, including the existing blood vessels.
A chamber used for growing organs outside the body (Photo: Nature)
The team then injected cells from human umbilical veins to line the blood vessels, alongside kidney cells from newborn rats to help regrow other tissues.
The organ was grown in a chamber that simulated the inside of a body, regenerating the kidney, which was then transplanted into a living rat.
So far, the lab-grown kidney hasn't worked perfectly. In tests before it was transplanted, it produced about a third as much urine as a normal kidney, and once inside the rat's body, efficiency dropped to five per cent.
But Dr. Harald Ott, the lead researcher, told the BBC that restoring even a small fraction of kidney function could allow patients to get off dialysis machines: "If you're on hemodialysis then kidney function of 10% to 15% would already make you independent of hemodialysis. It's not that we have to go all the way."
The ultimate goal is to grow replacement kidneys for people but it won't be easy.
Human kidneys are large, making it tough to get the cells in the right place so it all works properly. Plus, researchers have to prove that lab-grown kidneys will work over the long run.
A kidney in a bioreactor after seeding with cells (Photo: Nature)
Although this is a breakthrough, successfully transplanting a lab-grown kidney into a person is probably a long way off, according to one specialist.
Elaine Davies, head of research at Kidney Research UK, told the Guardian the new research is "fascinating science," but that it may not be practical for humans any time soon: "I'm not saying we won't get there but it could be in [many] decades' time."
Lab-grown organs have been successfully transplanted into people before.
In 2006, bladders made from patients' own cells were implanted, and windpipes have been transplanted. But the kidney is a "solid" organ, meaning it's more complex than a "hollow" organ like a bladder.
Here are some facts from the Kidney Foundation of Canada:
An estimated 2.6 million Canadians have kidney disease or are at risk of having it.
The two leading causes of kidney failure in new patients are diabetes and renal vascular disease (including high blood pressure).
The number of Canadians receiving treatment for kidney disease has more than tripled in the past 20 years.
Hemodialysis, the treatment used in most dialysis cases, costs about $60,000 a year per patient.
Kidney patients waited an average of 3.5 years in 2010 for a deceased-donor kidney transplant.
Also in 2010, a third of people who died while waiting for an organ donation were waiting for a kidney.
The need for organs outpaces the supply.