Wearable Artificial Kidney Potential Alternative to Dialysis

Pam Harrison

November 07, 2015

SAN DIEGO — A wearable artificial kidney has passed a third proof-of-concept trial: patients receiving hemodialysis who wore the device remained hemodynamically stable for 24 hours, and fluid removal was consistent with prescribed ultrafiltration.

"We do not do a good job at answering the unmet needs of our dialysis patients," said Victor Gura, MD, a nephrologist at the Cedars Sinai Hospital, Los Angeles, who is also from the David Geffen School of Medicine at the University of California, Los Angeles.

"The draconian impositions we make on these patients in terms of not only being tethered to a machine ('doing time' as patients say) but also the limitations of diet — two glasses of orange juice and a bag of potato chips is enough to kill these patients" — don't make for a very good life, he said.

Dr Gura, who invented the wearable device, spoke at a press briefing here at Kidney Week 2015: American Society of Nephrology Annual Meeting.

Dialysis on a Belt

The wearable artificial kidney is a battery-operated belt-like device (think construction workers' belts from Home Depot) that miniaturizes the functions of a 300-pound dialysis machine in just 11 pounds, which is light enough to allow patients the freedom to move.

The device also uses just a half a liter of water compared with the 40 gallons of water required during a normal session of hemodialysis.

In an earlier proof-of-concept study involving eight patients requiring hemodialysis published in the Lancet, Dr Gura and colleagues report that their wearable hemodialysis device showed promising safety and efficacy results, although further studies would be necessary to confirm their findings ( Lancet. 2007;370:2005-2010).

In the current trial, Dr Gura and colleagues tested the wearable artificial kidney on seven more patients receiving hemodialysis at the University of Washington in Seattle. The researchers aimed to determine the safety and efficacy of the device in achieving solute electrolyte and volume homeostasis during a 24- hour period.

"The difference between this trial and the one we did previously was that the regulators allowed patients to wear the [device] for 24 hours for the first time," Dr Gura explained.

Of the seven patients who tested the device, five patients completed the planned 24 hours of study treatment, whereas the remaining two patients completed 4 and 10 hours of treatment, respectively.

Six of the seven patients were mobile while undergoing dialysis with the wearable kidney.

Laboratory and hemodynamic parameters remained stable during the 24-hour test run.

Table. Laboratory and Hemodynamic Parameters During the 24-Hour Study Interval

Laboratory Values Baseline, Posthemodialysis 24 Hours After Dialysis With Wearable Kidney
Sodium, mEq/L 131 135
Potassium, mEq/L 3.8 3.9
Phosphorus, mg/dL 3.1 3.0
Creatinine, mg/dL 3.5 3.9
Hemoglobin, mg/dL 10.4 11.1
Systolic blood pressure, mm Hg 140 127
Diastolic blood pressure, mm Hg 77 78

In addition, patients were purposefully told to eat foods that are high in phosphorous, and all the electrolytes remained stable, even in the absence of phosphate binders, Dr Gura reported.

"Now, 21 patients in the three proof-of-concept trials have worn this device, and nobody died or got sick or had itching or diarrhea or vomiting, and there were no drops in blood pressure, which happen all the time with standard hemodialysis," said Dr Gura.

"The limiting factor to have patients using this device is money," he added. "But we have now proven the concept in Italy, London, and now Seattle, and it's time to get serious and make things happen, and we will."

Change in Lifestyle

Asked by Medscape Medical News to comment on the wearable device, Eli Friedman, MD, distinguished teaching professor from the Downstate Medical Center in Brooklyn, New York, agreed with Dr Gura that the time and effort demanded by a dialysis regimen require a change in lifestyle that impinges on quality of life.

"Because of a decreasing number of donor kidneys in the US, while at the same time the number of kidney failure patients grows, the US confronts the reality that a treatable fatal disease may go either untreated or suboptimally treated," Dr Friedman said.

In fact, all programs treating kidney failure acknowledge that optimal treatment is not available for the majority of patients with end-stage renal disease, he added.

Alternatives to dialysis currently being explored include xenotransplanted kidneys, championed by the Starzl Institute at the University of Pittsburgh; "bionic" kidneys; and simplified dialysis regimens.

Dr Friedman himself has contributed to innovations in the field with the invention of a "suitcase kidney" that could be taken on trips and was easy for patients to use.

"Adventurous patients used the device for trips and at home, but found it cumbersome compared with going to a dialysis center for treatments," he acknowledged.

However, Dr Gura and others have progressively decreased the bulk and complexity of a portable device to the extent that subjects can wear the device while living something close to normal lifestyle, he said.

Probiotic Bacteria

Alternatives to the wearable kidney may still emerge in the form of probiotic bacteria that patients would take orally and that, in theory, would digest the retained wastes of uremia and detoxify patients with end-stage renal disease, said Dr Friedman.

Trials evaluating the use of probiotic bacteria are about to begin, including one at Dr Friedman's Center.

"Thus far, we can convincingly say that if you are a rodent whose kidneys have been destroyed or removed, prolongation of life for months may be attained by treatment with probiotic bacteria," he explained.

"And while Gura's [device] may prove preferable to standard dialysis, my guess is that patients' desire for a more tolerable therapeutic option, such as a probiotic formulation, will continue until we find a way to either grow kidneys from stem cells, as is now being pursued by a team at the Massachusetts General, or perfect a method to turn off the rejection response."

The study was supported by an unrestricted gift from the Wearable Artificial Kidney Foundation and by Blood Purification Technologies, Inc. Dr Gura is chief medical officer and scientific advisor to Blood Purification Technologies, Inc, the developer of the wearable artificial kidney dialyzer. Dr Friedman has disclosed no relevant financial relationships.

Kidney Week 2015: American Society of Nephrology Annual Meeting: Abstract SO-PO1116. Presented November 7, 2015.


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