Why Scientists Are Excited - Meet the Podocyte
Breakthroughs Coming at Fast Pace

At a meeting co-sponsored by the NephCure Foundation, scientists from around the world shared their findings about the podocyte, a strange-looking cell with tentacle-like "feet," that seems to be a key in glomerular disease.

The meeting discussed a wave of new discoveries in which researchers have learned of new molecules that are key to podocyte function. As they better understand how the podocytes work, scientists are hopeful of finding better ways to treat - and some day cure - conditions such as Nephrotic Syndrome and FSGS.

Kidney experts have known for decades about the existence of the podocytes, which sit on the surface of the glomerulus, the collection of capillaries found in each of the one million filtering units in the kidney. The podocytes and their many branches of foot-like extensions (foot processes) create a lattice-type network around the capillaries and play a huge role in filtering the waste-laden blood coming through the glomerulus. (See more on the glomerular filtering function here.)

"In the past 18 months, some of the molecules that cause the inherited forms of FSGS have been identified," said Martin R. Pollak, M.D., of the Harvard Institutes of Medicine, a podocyte researcher and member of the NCF Science Advisory Board.

"These molecules exist in everyone, but in the familial form of FSGS, they are altered. The identification of these molecules which when altered cause the disease is very important in helping us understand how the podocyte works. Finding these molecules helps find other molecules and I think things are going to happen very rapidly now."

"Not all kinds of Nephrotic Syndrome are products of podocyte problems", said Dr. Pollak,"but the most common forms, including Minimal Change Nephrotic Syndrome and FSGS are." (He calls these "overlapping" diseases, since patients with FSGS may or may not have Nephrotic Syndrome and vice versa.)

Dr. Pollak uses the analogy of a car to illustrate the importance of the podocyte discoveries involving inherited forms of FSGS.

"There are many parts to a car and a lot of reasons it might not work," he said. "That's why it's important to find out that taking out a certain part can keep the car from operating. Similarly, there are a lot of different proteins in the podoycte that work together and if you remove any one of them or alter one of them, then the podocyte won't work."

Finding altered podocyte proteins that cause inherited forms of FSGS is like discovering that a missing or altered engine part causes a malfunction of the car, he said. Because of the altered protein, the podocyte does not work correctly and the kidney filtering mechanism is abnormal.

The protein discoveries were discussed during the Podocyte Symposium at the University of Michigan last Fall, an event co-sponsored by NCF which brought together world leaders in glomerular injury research. For a list of speakers at the symposium, visit here International Symposium on Podocyte Biology.
Also discussed during the meeting, said Dr. Pollak, was the development of new tools to study podocytes in mice.

"Every lab animal is a compromise in some sort, but what's good about mice is both that they have kidneys that are not much different from humans, and that you can genetically engineer mice to do a more detailed explanation of what these podocyte molecules are doing."

Dr. Pollak, who has been studying in the field for four years, said the new discoveries were generating excitement among researchers, but more funding would help research efforts to grow. "There is never enough funding to do all the good clinical and laboratory research that needs to be done," he said.