Balkan nephropathy (BN) is an endemic disease, which leads to
end-stage renal failure and artificial
renal replacement therapy. Pathologically it is characterized by progressive
interstitial nephritis in a large population of villages situated in the proximity of a bend of the Danube up to a distance of 100 km from the river in several parts of Bulgaria, Romania, and the former Yugoslavia. The urinary
proteins of 19 patients with BN from the region of Vratza, Bulgaria were examined using ultrathin layer
sodium dodecyl sulfate (SDS) pore-graduated
polyacrylamide gel electrophoresis (PAGE) and
silver staining. The documentation of urinary
proteins pattern was performed using
laser densitometry and consecutive electronic processing for the purpose of characterizing and quantifying
protein excretion. Our results show that the
proteinuria of BN is predominantly tubular, consisting of low molecular weight species (10-65 kilodaltons). The amount of tubular
protein changes with the progression of the disease. SDS-
polyacrylamide gel electrophoresis (PAGE) is a diagnostic method for early diagnosis of tubular failure in BN. Using our method of SDS-PAGE, tubular failure can be detected even at a total
protein concentration below 0.1 g/L and when the serum
creatinine concentration is normal. Additionally, our method of SDS-PAGE supports the differentiation of BN from glomerular disease.