Human Nephron Filtration (HNF) artificial kidney device

The future’s so bright, 8)


The Human Nephron Filter: Toward a Continuously Functioning, Implantable Artificial Nephron System
Allen R. Nissenson(a), Claudio Ronco(b), Gayle Pergamit©, Martin Edelsteinc, Richard Wattsc

aDepartment of Medicine, Division of Nephrology, David Geffen School of Medicine, Los Angeles, Calif., USA;
bDepartment of Nephrology, St. Bortolo Hospital, Vicenza, Italy, and
cBiophiltre, Inc., Burlingame, Calif., USA

Address of Corresponding Author

Blood Purification 2005;23:269-274 (DOI: 10.1159/000085882)


Background: Nearly 900,000 patients worldwide have end-stage renal disease and require dialysis or kidney transplantation, and this number is expected to more than double by 2010, placing considerable stress on healthcare systems throughout the world. Despite the availability of these forms of renal replacement therapy for nearly four decades, mortality and morbidity is high and patients often have a poor quality of life. Methods: We have developed a human nephron filter (HNF) utilizing nanotechnology that would eventually make feasible a continuously functioning, implantable artificial kidney. The device consists of two membranes operating in series within one device cartridge. The first membrane mimics the function of the glomerulus, while the second membrane mimics the function of the renal tubules. Findings: The device has been computer-modeled and operating 12 h/day, 7 days/week, the HNF provides the equivalent of 30 ml/min glomerular filtration rate (compared to half that amount for conventional thrice weekly hemodialysis). Conclusions: The HNF system, by eliminating dialysate and utilizing a novel membrane system created through applied nanotechnology may represent a breakthrough in renal replacement therapy based on the functioning of native kidneys. The enhanced solute removal and wearable design should substantially improve patient outcomes and quality of life.

Copyright © 2005 S. Karger AG, Basel

Full Article (pdf)

Author Contacts

Allen R. Nissenson
UCLA Medical Center
200 Medical Plaza, Suite 565
Los Angeles, CA 90095 (USA)
Tel. +1 310 825 9464, Fax +1 310 206 2985, E-Mail

Article Information

Accepted: September 10, 2004
Published online: May 20, 2005
Number of Print Pages : 6
Number of Figures : 6, Number of Tables : 2, Number of References : 21

Oh wow, this is fantastic! Just as I thought, …“Think Small”…the smaller the better… 8)

Nanotech is gonna bring some incredible good to be true miracles!!

“Nano to the Rescue!”

Thanks for sharing Michael!

Just wish everything didn’t take so long.

It’s getting closer…just around the corner…

Here is a lot more information presented in five videos - no dialysate required. Cross posted from
The future of dialysis: T and G membranes

This is a great lecture class forum: Quest for a Wearable Kidney: Will Nanotechnology Make a Difference? presented as five videos. Totaling about two hours in length the videos present a comprehensive look at the sort of technology being developed to improve the effectiveness of hemodialysis. Specifically they look at nanotechnology, surveying where the field has been and where nanotechnology is going, with particular emphasis on hemodialysis.

This comes from the Center for Integration of Medicine & Innovative Technology (CIMIT). CIMIT’s mission is to improve patient care by bringing scientists, engineers, and clinicians together to catalyze development of innovative technology, emphasizing minimally invasive diagnosis and therapy. The presentation seems to be to an audience of no particular background - I believe the forum is open to the public - so for the most part the information is accessible. Over all it is well done.

The first video is Joseph Bonventre, MD, PhD, Robert Ebert Professor of Medicine and Health Sciences and Technology, Harvard Medical School; Director, Renal Division, Brigham and Women’s Hospital. He gives the background explanation of dialysis and outlines the clinical need for improved hemodialysis.

The second video is Theodore I. Steinman, MD, Clinical Professor of Medicine, Harvard Medical School; Beth Israel Deaconess Medical Center. His presentation on Human Nephron Filters and a Continuous Functioning Artificial Nephron is pretty exciting. A lot of new information. One concept I had not heard before is the idea that this could work without dialysate - on a nano-scale solute transport would occur due to convection. So called passive transport. One concern I have always had regarding a wearable kidney is the blood access. Towards the end of the video he shows a slide and references a “double lumen needle and immobilization device” the slide is intriguing. It shows that there is a proposed solution but the details remain to be seen.

The third video is Greg Erman, MBA, Serial Entrepreneur and former President & CEO, Renalworks Medical Corporation who goes over the business challenges of bring a continuous mode of dialysis to market and he addresses the issue of blood access by pointing out that implanting the device solves the issues around needles and catheters. I can’t understand his point about dialysis costing Medicare 100,000 a year - that would have to be total costs, Medicare’s share is about $70,000. However, he contends that there isn’t enough money to be saved through more dialysis. I look at those numbers and reach the opposite conclusion.

The forth video is Jeffrey Borenstein, PhD, Director, Biomedical Engineering Center; Distinguished Member of the Technical Staff, Charles Stark Draper Laboratory; Program Leader for Biomaterials and Tissue Engineering and Draper Laboratory Site Miner. He goes over where the technology is and what is left to do - the slides are not in view through most of the video.

The fifth video is a question and answer session with some good questions and a bit of industry gossip.

This is all very encouraging.

Cross posted from

CKD overview video: Dr. Bonvertre

On Saturday I wrote The future of dialysis: T and G membranes about CIMIT’s forum: Quest for a Wearable Kidney: Will Nanotechnology Make a Difference? . This forum seems to be one of a series of forums on various medical topics. They’re open to the public (wish I lived in Boston) and are put on by CIMT to further their mission of improving medical care by spreading knowledge. The forum weaves in an evaluation of the technology from a business perspective which is critical. As was seen with the Aksys PHD and early efforts to improve the artificial kidney the speakers mention.

Quest for a Wearable Kidney: Will Nanotechnology Make a Difference? looks at work to improve dialysis by improving the artificial kidney, the dialyzer. The whole forum is very good and there is a lot to it - five video segments; I thought this week I would review one video segment a day. The first video, about ten minutes, long features Joseph Bonventre, MD, PhD, Robert Ebert Professor of Medicine and Health Sciences and Technology, Harvard Medical School; Director, Renal Division, Brigham and Women’s Hospital.

Dr. Bonvertre gives the overview of the kidney, CKD, and previous “new approaches” to improving the dialysis experience. I think Dr. Bonvetre is presenting the case for relevance and establishing that there is a market for new and better devices: the US already spends a lot of money treating this disease; there are a lot of people in the dialysis pipeline. Usually I see this sort of presentation it is at a renal industry event so often the relevance piece is taken for granted or addressed in passing.

CIMIT is trying to catalyze development of innovative technology, emphasizing minimally invasive diagnosis and therapy. If any therapy is invasive it’s hemodialysis, particularly incenter hemodialysis, so welcome CIMIT we can use the help. Video one gives a good overview of CKD and dialysis but it misses one salient point. After 45 years the incenter dialysis model has worn a deep rut in the course of CKD; it will take a novel approach to get the provision of dialysis out of that rut.

Cross posted from
Dialysis: a future with nanotechnology

                  On Saturday I wrote [The future of dialysis: T and G membranes]( about [CIMIT]('s forum: [Quest for a Wearable Kidney: Will Nanotechnology Make a Difference?]( . The forum is broken up into five video segments; I thought this week I would review one video segment a day. On Monday I wrote[CKD overview video: Dr. Bonvertre]( about the first video segment of the forum.  This [second video]( is about 45 minutes long and features Theodore I. Steinman, MD, Clinical Professor of Medicine, Harvard Medical School; Beth Israel Deaconess Medical Center.

Dr. Steinman gives a fascinating talk picking up the story where Dr. Bonvertre left it. Dr. Steinman looks to what the future of dialysis may hold as work proceeds on “developing a new type of functioning artificial nephron”. At one point in the video he gives a tour of the human nephron but for the most part this video segment covers nanotechnology and the sort of impact nanotechnology is expected to make on the provision of dialysis.

Dr. Steinman goes over some of the common clinical impacts of standard dialysis; he suspects that chronic inflammation may be at the heart of the cardiovascular problems associated with dialysis. He makes the point that “advances at the margin” in the provision of dialysis do not address some of the major problems that we need to address to improve the quality of patients lives.

Dr. Steinman gives some nanotechnology background. Which for the most part I feel hopeful when he talks about manipulating pore size of the semipermeable membrane to make a better dialyzer but when he talks about microscopic nano-robots, nano drug delivery devices and multipurpose nano particles … well I wonder if society is prepared for injectable nano particles, let alone nano-robots. Thankfully that is not an issue dialyzors will have to pioneer. The nanotechnology that will revolutionize dialysis has to do with a nano-engineered dialysis membrane with specially devised nanoscale pores.

As a dialysis geek or wonk I have to say, I was in heaven when he started talking about membrane pores. This is where dialysis actually happens. Right there at the semi permeable membrane a molecule moves across from the blood space into the dialysate. That moment is the key, repeated many times. Here Dr. Steinman talks about unselective pores v highly selective pores and his plan to selectively filter and then selectively reabsorb just the molecules we want, he describes a pore library that will offer just the right membrane pore for each component of plasma, good and bad.

He lists the faults of today’s modern dialyzers:[ul]
[li]unselective transport; wide distribution of pore sizes leads to statistical filtration[/li][li]relatively thick, often low flux[/li][li]no opportunity for precise atomic placement[/li][li]long pore pathways[/li][li]tortuous path[/ul]Thats an interesting concept “statistical filtration”. Today dialysis is based on the concept that it’s bound to work. That the size and shape of the membrane pores vary enough that statistically you’re bound have some proportion of pores that are suitable. heh[/li]
If that wasn’t enough for one video he then comes to the meat of his talk on the Continuous Functioning Artificial Nephron (CFAN). This is the device that uses the G and T membranes to create a highly efficient dialyzer. G stands for glomerulus, T stands for tubular together the mimic the human nephron. Dialysis using this new technology (and running 12 hours a day 7 days a week) could provide a GFR equivalent to 30 - that’s barely stage 4 CKD. Someday the technology could provide a GFR equivalent of 60 - barely stage 3.

So the G membrane would take stuff out, the T membrane would put stuff back. What each membrane would do exactly would depend on which pores you incorporate into the membrane - the membranes would be customized based on prescription. Fluid removal based on pores chosen. This could work on a standard machine but the technology opens up many possibilities in design because it doesn’t use dialysate. Solute transport occurs by convection - passive transport.

With no dialysate an implantable device looks more practical and certainly a wearable kidney is easier to create. However a wearable kidney again brings cannulation into play and about five slide from the end Dr. Steinman shows what a double lumen needle and immobilization device looks like. Double lumen so you use one needle for venous and arterial duties but how can it be immobilize? It looks to be a tape based contraption with a portal in the tape that presumable is centered on a buttonhole. Then once the needle is in, it looks like a cap disengages from the tape to snap over the needle “locking” it to the tape? Maybe. And then there might be a tab of sur-seal material in a circle that covers the cannulation site on ex-cannulation. It would be helpful to see this system demonstrated. I’m good at making stuff up. Still not sure about wearing it for 12 hours a day. Maybe.

So many things come to mind but for one thing they’re imagining a waste bag taped to the thigh. Clearly the better way would be to wear it like a shoulder holster and run the drain line down to the zipper. I hope that highly efficient, engineered membranes are coming; the next video segment touches on the business side of the equation. One problem Dr. Steinman mentions is coagulation and how to keep it from clotting up. I guess that is where the nano-robots come in or maybe nano heparin dispensers. Unless cost is prohibitive we should be seeing nano-engineered membranes someday. Maybe they can be reused if they are expensive. Cleaned between treatments by nano pore cleaners. Endless possibilities. All very hopeful.

Hi Bill,

Thanks so much for cross-posting your very interesting observations. We’re very glad to have them here, too! (And I love your blog site). I remember how exciting it was to hear about nanotechnology–especially membrane pore specificity at the Annual Dialysis Conference about 3 years ago. Actually, it was the International Society for Hemodialysis (, which has as its membership most of the international thought leaders who truly are dialysis experts. They held a session that was a preconference workshop, and it was awesome.

I keep forgetting to mention that the Nissenson artificial kidney that someone referred to earlier (it uses live cells) is meant only for acute, not chronic, dialysis, or at least that was the case when I heard about it last.

	 		Cross posted from [](

Dialysis nanotechnology forum, video 3

On Saturday I wrote The future of dialysis: T and G membranes about CIMIT’s forum: Quest for a Wearable Kidney: Will Nanotechnology Make a Difference? . The forum is broken up into five video segments; I thought this week I would review one video segment a day. On Monday video one CKD overview video: Dr. Bonvertre. Tuesday video two Dialysis: a future with nanotechnology. Video three (about 23 minute run time) looks at the business side of improving the provision of dialysis.

Greg Erman, MBA, Serial Entrepreneur and former President & CEO, Renalworks Medical Corporation is featured in video three. He goes over the business challenges of bring a continuous mode of dialysis to market. He is speaking from a private equity perspective, a venture capital perspective. This is a critical point of view since funding is required to bring any product to market. However, I was surprised that his presentation missed many of the ESRD program’s funding subtleties.

He starts with the premise that Medicare spends on average $100,000 a year per dialysis patient. That’s not the number. Medical expenses for all dialyzors form a bi-modal distribution. There is the average cost for people that are Medicare primary and another average cost (much higher) for people with private insurance primary. The United States Renal Data System publishes Medicare’s dialysis cost data. The 2005 data is available here (pdf link). There is a lot of detail available.

From USRDS table K2: Total Medicare cost for ESRD (dialysis and transplant) is 19.3 billion dollars in 2005: total outpatient 7.15 billion (almost all dialysis); total inpatient 6.96 billion (transplant and dialysis); total physician/supplier 4.1 billion (transplant and dialysis, includes post transplant medications). 75% of the people on dialysis have this cost profile (remembering that Medicare pays 80% so total medical cost per Medicare primary patient would be 125% of Medicare expenditures).

On the per patient per year level it’s $24,000 outpatient, $20,000 inpatient and $14,000 physician/supplier. To get to that $100,000 per patient average for the whole program you can work backwards to calculate the average cost to private insurers to support someone who is on dialysis. With just 10% of the patient population their average cost would be on the order of $300,000 with the about the same distribution among inpatient, outpatient and physician. A classic bimodal distribution with very few people in between the two modes.

The problem from the equity perspective is that you have to work under the Medicare cost structure. The private pay cost structure is far more generous but Medicare is the ESRD rule setter in the United States. Many products could thrive under the private reimbursement constraints but in the US it has to work under the Medicare reimbursement framework. Instead of $100,000 the relevant number is Medicare’s share of the their beneficiary’s cost, a more modest $55 -$60,000 for those not in skilled nursing facilities.

One thing that Mr. Erman said that was wrong and offensive was his description of the ESRD program under Medicare as “the last social welfare program left in the country for healthcare. Anybody is entitled to get covered for dialysis if they lose their kidney function.” Medicare is insurance. It is not means tested, you earn it through working enough quarters. If you don’t have the quarters of paid employment (and therefor the quarters of paying FICA taxes) you don’t qualify for the Medicare ESRD program. True it is subsidized insurance but Erman mischaracterizes the program.

Beyond implying that dialyzors are uniquely on the dole he states that dialyzors are “very suicidal” and “a large percentage of patients are suicidal”. Now it is true that depression is a problem in many chronic illnesses but it is wrong to imagine that dialyzors need to be on a suicide watch. Depression can be a consequence of Chronic Renal Under Dialysis and/or untreated anemia but I haven’t seen data to suggest “a large percentage of patients are suicidal”. Mr. Erman seems to take this as a given and a reason why NxStage and other healthier home modalities don’t have more adopters.

Australia and New Zealand have much higher adoption rates of home hemodialysis (13%) and peritoneal dialysis (25%) than the US. Her in teh US the Northwest Kidney Centers in Seattle has 5% on home hemodialysis and 9% on PD. Obviously there is something else generally preventing people in the United States from adopting home therapies. Home Dialysis Central works hard to promote home therapies, compiles and studies the barriers to going home and being suicidal is not on the list.

Another point Erman makes is that unlike cardiovascular patients, dialysis patients don’t offer savings from fewer hospitalizations. That was a surprise to hear. The USRDS data shows that Medicare spends nearly as much on inpatient ESRD procedures as it does on outpatient procedures. Looking at the sample Dialysis Facility Report the national average number of days in the hospital per admission for people on dialysis is 8.1 days. On average dialyzors spend 16 days a year in the hospital. A significant number of those admissions are due to access issues but over half are for something else.

The problem isn’t that there isn’t money to be saved it’s that because of the artificial accounting wall between Medicare Part A and Medicare Part B savings on hospitalizations can not pay for additional Part B dialysis. The problem is not with the dialyzors. I think the problem is that our system of venture capitol funded innovation does not work when it comes to a condition dominated by Medicare. The difference between the cardiac market and the dialysis market isn’t based on the personalities of the patients and doctors, the difference is due to the funding models.

Venture capitalists look to replace labor expenses with technology expenses. I believe on average a dialysis patient consumes 5 to 10 hours of labor a week. How many hours of labor would continuous dialysis consume a week? Currently home therapies like NxStage have an economic model that depends on labor savings. The bigger pot of money to be saved would be in hospitalizations but for Part A spending to enter the calculus it would require a change in DC.