FSGS Pathophysiology: Podocyte Injury Across the Lifespan

Welcome back to another Managed Healthcare Executive Between The Lines series. In "FSGS Pathophysiology: Podocyte Injury Across the Lifespan," moderator Kirk Campbell, MD is joined by Howard Trachtman, MD to open the series by unpacking the podocyte injury at the center of focal segmental glomerulosclerosis.

In this opening episode, Dr. Kirk Campbell and Dr. Howard Trachtman lay out the biology behind focal segmental glomerulosclerosis, or FSGS. Dr. Campbell explains that FSGS is not one disease but a histologic pattern: segmental scarring of glomeruli, the kidney's basic filtering units. He walks through the range of underlying causes, including diabetes, obesity, sickle cell disease, infections, and a growing list of genetic factors. Regardless of etiology, Dr. Campbell notes, injury converges on the podocyte, the key cell implicated in FSGS pathogenesis. He describes how the clinical presentation is often nonspecific. Many patients are identified incidentally through proteinuria on routine urinalysis, and the disease can present anywhere from nephrotic to nephritic syndrome, with variable degrees of renal insufficiency.

Dr. Trachtman builds on this overview with an important caveat: FSGS strikes patients of every age, from children to older adults, and its adverse consequences are consistent whether a patient is 10, 30, or 50 years old. He argues this should keep the condition top of mind for nephrologists treating both pediatric and adult populations, since the underlying risk doesn't diminish with age. The two physicians frame this foundational discussion as the entry point for the rest of the series, which will trace FSGS from mechanism through the pivotal DUPLEX trial data to payer coverage policy. Their exchange sets up why a single unifying pathophysiologic thread, podocyte injury, matters clinically: it explains why treatments targeting that injury pathway, rather than the specific upstream cause, have become central to how the field now approaches management, a theme the panel returns to repeatedly as the conversation moves toward FSGS's evolving treatment landscape.

The next episode in this series, "FSGS Subtypes and Genetics: Why Classification Still Falls Short," features the panel breaking down FSGS's genetic and immunologic subtypes and the regulatory path that led to sparsentan's approval.