Causes of Focal Segmental Glomerulosclerosis
The segmental sclerosis of glomeruli reflects the result of damage reparation of local inflammation. The simple episodic sclerosis itself cannot reflect the feature of primary damage. Primary FSGS is often accompanied by the harms of glomrular epithelial cells. The epithelial cells of visceral layer, or you can call it podocyte, plays an important function in the onset of the primary FSGS.
Under the function of various factors such as toxins, inflammation harms, the epithelial cells happen with damage and podocyte happens with coalesce, and also, the glomerular filtration membrane permeability would increase, thus leading to the heavy proteinuria. Epithelial cells can produce various kinds of cell factor and growth factor, especially the TGF-B. TGF-B promotes the increase of synthesis of collagen from epithelial and mesangial cells and also lead to the decrease of degradation, therefore leading to the glomerular sclerosis.
Besides, the high filtration and high perfusion also play an important function in the formation of FSGS. High filtration and high perfusion irritate the renin-angiotensin system, thus leading to the increase of proliferation of mesangial cells and the ECM, so glomerular sclerosis is aggravated.