Structural Anatomy of the Nephron and Its Clinical Implications in Early Kidney Disease Detection

Abstract

The structural alterations in the nephron, which form the functional unit of the kidney, are closely related to chronic kidney disease (CKD) progression. The cross-sectional design was used, and the healthy individuals and patients with CKD in stages 1-3 participated. The structure of nephrons was determined by non-invasive imaging (ultrasound and Computed Tomography, CT), and biopsies were performed when needed. Clinical data such as serum creatinine and estimated glomerular filtration rate (eGFR) were taken to be able to correlate structural changes with the kidney function. The findings showed that there is substantial structural damage in early stages of kidney disease, where glomerulosclerosis and tubular atrophy were present in 5% and 10% of the participants at mild stages, respectively. The higher the disease severity, the higher the percentage of affected persons by 35% of the glomerulosclerosis and 50% of the tubular atrophy. In severe CKD, nephron size has reduced to 120 μm compared to the normal kidney of 150 μm. There was also no interstitial fibrosis in normal kidneys, but in 8% of mild cases of the disease and 45% of severe disease. It was found that the nephron structural changes were strongly correlated with the markers of kidney function, which indicates that early changes in the nephron could be used to be reliable biomarkers to diagnose CKD at the early stages. These results highlight the significance of the nephron structural analysis in the early detection and management of kidney disease.