While there are 18,000 kidney transplants performed annually in the U.S., the sad truth is that another 100,000 persons are waiting for suitable organs (not to mention the 400,000 who are required to undergo dialysis). Hopefully, however, the next decade will bring that figure down to near zero.
In a recent Nature Medicine article, it was disclosed that science is inching ever-closer to manufacturing replacement organs. Investigators at Massachusetts General Hospital (using rats) have developed a procedure whereby the non-functioning or donor organ is removed from the host and then, using a detergent solution, all the living cells of the donor organ are removed, leaving only the organ’s scaffolding. Then, the organ is repopulated with the proper cells (in the case of a kidney, with endothelial cells to replace the vascular system lining, and kidney cells for remaining structure). By adjusting the pressure through which cells are passed through the organ (through the renal artery for repopulating the vascular portions of the organ and through the ureter for populating the kidney tissue), the scientists were able to seed the organ with the appropriate number of cells, which were then implanted in the donee.
While the function of the kidneys were greatly reduced compared to normal kidneys, they did, in fact, start producing urine as soon as the blood supply was restored and there was no evidence of any clotting or bleeding. The researchers believe that the reduced functionality may have to do with the immaturity of the cells used to repopulate the kidney (the scientists in this study used kidney cells from newborn rats). It is possible that by allowing the seed cells to mature longer, full functionality could be obtained.
The positives of this research are many. By using the damaged organ of the individual, the scaffolding upon which the new organ is built is a perfect match, as it is the patient’s own kidney to begin with. Furthermore, through the use of stem cell research (which, by the way, has produced pluripotent cells from adult cells – negating any complaints about fetal stem cell use), science may be able to repopulate the scaffolding with the patient’s own cells – removing any complications from organ rejection and negating the need for anti-rejection drugs.
Scientists have successfully stripped cells from human kidneys to produce viable human scaffolding. This technique has also been done on hearts, lungs and livers. While not perfected and certainly not yet ready for human trial, it does provide hope that the next decade will find science up to the challenge of those in need of new organs.
Regeneration and experimental orthotopic transplantation of bioengineered kidney. Song, J.J., Guyette, J.P., Gilpin, S.E., Gonzalez, G., Vacanti, J.P., and Ott, H.C. Nature Medicine (2013) doi:10.1038/nm.3154 Published online 14 April 2013
See abstract here: http://www.nature.com/nm/journal/vaop/ncurrent/full/nm.3154.html
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