Nadia Galal Elhefnawy
1*, Nermine Mohamed Adb Raboh
1* , Ola Hassan Nada
1, Esraa Adel Mahmoud
1, Waleed Anwar Abd El Mohsen
21 Department of Pathology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
2 Department of Nephrology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
Abstract
Background: Focal segmental
glomerulosclerosis (FSGS) and Minimal change disease (MCD) are two disease
entities presented mainly by nephrotic syndrome. While 95% of MCD cases showed
complete remission on steroid therapy, 50% of FSGS cases progress to end stage
renal disease. Early sclerotic lesions in FSGS can be missed in routine H&E
examination.
Objective: To differentiate early FSGS from MCD by detection of
activated parietal epithelial cells (PECs) in early glomerular sclerotic
lesions using Claudin-1 immunohistochemical (IHC) staining and by examining
podocyte ultrastructural changes.
Materials and Methods: This retrospective study included 28
cases diagnosed as MCD and 20 cases diagnosed as early FSGS. Clinicopathologic data collection, claudin-1
IHC staining and reviewing ultrastructural changes were performed and the
results were statistically analyzed.
Results: A
statistically significant correlation was detected between claudin-1 expression
and the initial diagnosis of the studied groups (P=0.005). Claudin-1 was
expressed in a visceral location in (39.28%) of the biopsies initially
diagnosed as MCD thus were reevaluated as early FSGS lesions. 63.64% of these positive cases
were presented by steroid resistant nephrotic syndrome and 63.6% of which showed some ultrastructural
changes of FSGS in podocytes including abnormalities in mitochondrial shapes,
endoplasmic reticulum changes and a decreased number of autophagic vacuoles.
Conclusion: Claudin-1 is a novel diagnostic marker that can
differentiate between confusing cases of early FSGS versus MCD. Defective autophagy plays a role in the pathogenesis
of FSGS.