It is largely known an important dissociation between the histological data from kidney biopsy and clinical aspects: advanced glomerular lesions may be accompanied by a paucity of clinical impairment and, conversely, important clinical impairments (e.g. important proteinuria) may be accompanied by minimal histological modifications (e.g. minimal change disease). This clinical-morphological divergence might underpin a limited ability of clinical/hematological tests to identify renal diseases or an as yet unsatisfied method for the quantification of renal damage. The objective of this study has been to correlate quantitative morphological features from kidney biopsies with clinical and hematological parameters. Moreover, tubular measures and fractal dimension were also used as morphologic estimators of clinical values.
To this aim we quantified morphological parameters from thirty-six biopsy of patients diagnosed for diabetic nephropathy, hypertensive nephropathy or FSGS, using ImageJ software and specifically designed macros to derive new morphological estimators.
The main result of the present paper is that the relation between eGFR and glomerular density is not valid in the case of diabetic nephropathy. We rather observed that the only morphologic variable correlating with eGFR accross different conditions was the tubular density. We also verified that tubular density predicted for the levels of uric acid in different pathological conditions. We found that the fractal complexity of tubules (measured by the fractal dimension) was correlated to the eGFR but only in hypertensive patients, whereas this was not evident in FSGS and diabetic nephropathy.
These results suggest that the modification of eGFR is a poor predictor of the number of functioning glomeruli in the kidneys, whereas it is more closely related to the tubular density. Moreover, we propose the use of the fractal dimension as a new estimator of nephron integrity in hypertension.
