Another article about the artificial kidney

Thanks for the info but please refrain from posting links, when possible. The links go dead after some time and the news is no longer available.

December 13, 2012
Implantable Artificial Kidney Could Help Tens of Thousands: An Interview with Shuvo Roy, PhD

With nearly 100,000 patients awaiting a kidney transplant and fewer than one-fifth likely to undergo the procedure each year, a promising hybrid device that works from the inside to provide renal functions beyond dialysis 24 hours a day, seven days a week, has the potential to change a lot of lives, not to mention substantially lower Medicare costs.

Shuvo Roy, PhD, associate professor in the Department of Bioengineering and Therapeutic Sciences at the University of California–San Francisco School of Pharmacy and technical director of The Kidney Project (http://pharmacy.ucsf.edu/kidney-project/; Facebook.com/ArtificialKidney) updates Renal & Urology News on his group's work.

How did you begin to develop the artificial kidney?
Dr. Roy: In the early 2000's, we proved that the science worked. We took off-the-shelf, bulky, large, technology that we hooked up in a circuit to mimic how our kidneys work, and my colleague at the University of Michigan, Dr. David Humes, applied this to about 60 intensive care unit (ICU) patients who were suffering from acute renal failure. About half of them survived beyond six months—longer than they would have lasted on dialysis.

That clinical trial gave us a lot of confidence that this concept of a filter plus a bioreactor actually does provide a therapeutic benefit. But then the question became, “How do we take this concept from the large-scale technologies of the ICU and apply it to people who go to the dialysis center three times a week?”

And what was the answer?
Dr. Roy: The medical director on our team, William Fissell, MD, who is a nephrologist [with an engineering degree from Massachusetts Institute of Technology—Eds.], said we'd have to shrink the technology into something smaller that could be implanted; that could allow patients the freedom of mobility and the ability to eat and drink normally; and that could operate continuously, 24/7, to provide the benefit of toxin removal as well as the biological functions of the kidney that dialysis does not provide, such as help regulate blood pressure, help produce vitamins, and help with the acid levels of the blood.

How does the function of the artificial kidney differ from dialysis?
Dr. Roy: The five-year survival rate for dialysis hovers around 35%, but for kidney transplantation, it is well beyond 80%. The reason for that is dialysis simply does not provide the biological functions of a healthy kidney.

Our device mimics the native kidney, with a filter serving as the glomerulus. The filter is followed by a tubule—the bioreactor—which is lined with cells, to provide the full functions of a kidney. In typical dialysis you just do the filtration part; you don't mimic the cell part at all.

Our device will be connected to the blood vessels, as a kidney transplant would be. One very exciting aspect is the membrane technology we have developed for the hemofilter: It's so efficient that it will allow for filtration without the need for an electrical power supply, connections to the outside, or a battery. So just based on the blood pressure, we will be able to get therapy that's sufficient to keep the patient alive 24/7.

What is the status of the artificial kidney now?
Dr. Roy: Over the last 10 years, we have been on a journey to miniaturize the components of our device to the size of a small to-go coffee cup using silicon nanotechnology. We enclosed the cells of the bioreactor in a container with tiny windows that allow for interaction between the body and cells but prevent the body's immune system from getting to these cells.

We showed this to work on the bench, in small animals, in sheep, and in pigs with much success; it is all working in principle. The next step, which is what we are starting now, is to integrate the filter and the bioreactor into a single compact unit and do the animal testing that will let us validate this for subsequent human study.

I think we will be ready to test in humans by 2017, if not before. We are collaborating closely with the FDA as part of the agency's Innovation Pathways 2.0 program to design this research.

How temporary or permanent would the implanted artificial kidney be?
Dr. Roy: It's hard to say prospectively without doing the studies, but we hope that it will be one surgery to implant it, and that should be it. But we also recognize that you have to plan for maintenance or replacement: The filter could get clogged up, or the cells could die.

So, we have thought of a strategy where the artificial kidney gets implanted right underneath the skin. That way, components can be replaced in a minimally invasive procedure, which would probably be performed by a vascular surgeon. We do not anticipate the whole device having to be removed.

Based on our lab studies and what we can project, we think that no maintenance will be needed for at least one year.

Which patients would be eligible to receive the artificial kidney?
Dr. Roy: Today, 95,000 people are on the wait list for kidney transplants, which are still the gold standard for treating end-stage renal disease. In this country we do about 17,000 or 18,000 transplants per year, meaning that more than 75,000 people who require transplants won't get one this year.

So, the best candidates for us are probably people who are already on that list, but are low enough that the likelihood of them getting a transplant is not that great. If they are physically able to withstand the surgery for our device, they would qualify.

Where will the artificial kidney fall in terms of cost?
Dr. Roy: A typical dialysis patient today costs Medicare about $85,000 annually, and a transplant patient, after the initial surgery, costs Medicare about $30,000. Most of that $30,000 is spent on immunosuppressant medications to prevent rejection.

Our device will require surgery probably like a transplant surgery, although maybe not as complicated. But the patient will likely not require immunosuppressive drugs because our cells are protected from the patient's immune system. Maybe our device will cost about $10,000 to $20,000 a year in maintenance. I think if we're completely successful and enough patients on dialysis receive our device, we could lower the $30 billion Medicare currently spends on patients who have kidney failure to at least half that amount.

How do you expect survival rates to compare?
Dr. Roy: I do feel confident that our device will provide better survival than dialysis. Would it be as good as transplant? Again, prospectively it's hard to say, but we can hope the survival rates will be closer to those seen with transplants than those seen with dialysis because our device would provide many of the functions of a transplant.

http://www.renalandurologynews.com/implantable-artificial-kidney-could-help-tens-of-thousands-an-interview-with-shuvo-roy-phd/article/272364/