Leslie Spry, M.D., FACPNational Kidney Foundation spokesperson; Medical director, Dialysis Center of Lincoln, Neb.
Posted: 05/02/2013 5:46 pm
The city of Boston made front page news over the last few weeks due to the tragic marathon bombings and the events that followed. While this coverage has been extensive, there’s some other news from Boston — good news — that hasn’t been as widely broadcast. Massachusetts General Hospital, one of the major research institutions in the United States and the same hospital that treated many victims of the Boston Marathon bombings, recently released a big breakthrough. Researchers created an artificial rat kidney in the laboratory that was then transplanted into another rat and ultimately produced urine — a huge advance in the field of bioengineering.
Prior studies at the University of Minnesota produced an artificial rat heart by using a special solution to dissolve the cells from one rat heart while leaving the scaffold of tissue intact. In medical terms, this would be the connective tissue of the heart. This scaffold or skeleton of the heart was then perfused, or “flushed,” with stem cells from another rat and the new heart started beating. Researchers at Massachusetts General Hospital used this same technique to create the skeleton of the artificial rat kidney. This skeleton was then re-populated with cells from a different rat and a new kidney was grown in a bioreactor, which is a sterile vessel that can be used to grow tissues and cells. In what may have seemed straight out of a sci-fi film years ago, this “artificial,” or manufactured, kidney was then transplanted into the second rat and produced urine.
Good News for Rats, but What Does That Mean for Humans?
If instead of using a rat, we could perform this procedure on a pig kidney — which is about the size needed for a human kidney — then we could use the pig scaffold to create a kidney with human cells and ultimately create enough organs to meet the need of everyone on the waiting list. Obviously, bringing this to full scale and actually performing such a transplant is many years into the future, but perhaps it is not as far off as we thought.
By comparison, in an artificial heart, only muscle cells and nerve cells are needed to make a heart beat, so it’s possible to use only two or three different cell types to grow a new ticker. Creating a functioning kidney requires many different cell types because kidneys are complex organs that perform multiple functions. Kidneys consist of filters, called glomeruli, made from four different cell types. The kidney also consists of tubules, blood vessels, nerves, collecting ducts and specialized cells, all of which form an integrated but very sophisticated organ.
Given the organ’s complexity, this urine-producing artificial kidney represents a major leap forward in regenerative medicine. At the same time, it also represents a move away from efforts using stem cells to grow an entire organ from scratch. By creating a skeleton or “shell” of the organ to be produced and then re-populating this skeleton with kidney cells from another individual, it would not be necessary to use drugs that suppress the immune system. These are the drugs that must currently be taken for the lifetime of an organ transplant to prevent the body from attacking the new organ as a “foreign object” or invader in the body. Since the “artificial” organ would be created from the patient’s own cells, it could then be transplanted into that patient without fear of rejection or the need to take these medications.
While an artificial kidney may be the long-term solution to this problem, in the meantime, we at the National Kidney Foundation encourage you to learn more about organ donation and becoming an organ donor. Did you know that the kidney is one of the only organs that you can donate while you’re still living?
There are nearly 118,000 people waiting for lifesaving organ transplants in the United States and of these, over 81 percent await kidney transplants.
Due to rising rates of high blood pressure and diabetes — the two leading causes of chronic kidney disease — more and more people are added to the transplant list each year. In the U.S., we are currently only performing about 16,500 kidney transplants per year. Unfortunately, due to the lack of viable organs for transplant, the yearly number of kidney transplants performed has not changed in the past 10 years. Suffice it to say that we have a huge kidney shortage, and the gap continues to widen.
Got a question about this research advancement or kidney transplantation in general? Ask me in the comments below.