A real artificial kidney… Come on, you know that sounds funny.   But, oh, so critical.  Because transplantation needs kidney donors that are compatible- and we- not just America, but the world- find kidneys in short supply, and compatibility an even tougher hurdle.

There are 100,000 folks or so on the waiting list for a kidney transplant, with about 10,000 of them dying each year- before reaching the top of the list, because we only manage to provide about 18,000 transplants annually.  (And, 40% of those transplants fail in less than a decade, leading to even more deaths.)

Dialysis keeps the patient alive.  But, it drains hours and energy from the lives of each of the patients. So, we really do need artificial kidneys.  Which is what Dr. Harald Ott’s group (with Drs. J. Song, J. Guyette, S. Gilpin, G. Gonalez, and J. Vacantia) at Mass General Hospital are trying to deliver to us. Right now, it’s only for rats, but it’s a great big step.

Ott’s group takes an existing kidney and subjects it to a chemical cleaning, stripping away all the cells, leaving only the superstructure- the collagen scaffolding. The fibrous protein structure has all the “functional plumbing” of the kidney.   (I’ve reported that other folks – such as Dr. Anthony Atala, are using 3D printers to make the scaffolding.) This is then the substrate upon which neonatal kidney cells and endothelial cells are grown (pumping the vascular and renal cells through the renal artery, which is part of the scaffold)  to reproduce a new, functioning kidney.  If we did this with human organs, then a patient could get the organ- comprised of his or her own cells.

The “regrowth” process for the rat kidneys takes less than a week, typically three to five days. And, these ‘new’ kidneys produced urine and filtered waste. And, the condition of the kidney that was ‘scrapped” down to the scaffold is not terribly critical- it’s the scaffold itself that is the key factor.  (In other words, the original kidney does not have to be in perfect shape- which is the criteria for normal transplants.)

The testing to determine how the kidney function was effected in vitro (literally this means under glass, but we use the term to mean not in “real” conditions)– and also via implantation into the rats.  Note- these new devices were not as efficient as the “real” kidneys, but the artificial ones did provide better results than one would get from dialysis. Moreover, there may be better “mixes” of cells to use that would provide better functioning kidneys.

Another key factor is that since the patient’s own cells would be used to make the kidney, there is no need for immune suppression drugs.  Since rejection is not an issue, the omission of such therapy won’t leave the patient at risk for those other diseases that the immune suppression therapy often does.

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