RESUMO
Randall's plaque theory is regarded as the most plausible mechanism of urinary stone formation; however, we speculated that urine proteins are necessarily involved in the process of stone formation. We focused on alpha 1-antitrypsin (alpha1-AT), a protein verified to be present in urinary calculi, and which is considered as a protein of inflammation, comparing its presence in healthy subjects and patients with urolithiasis. Quantitative analysis of alpha1-AT was performed with ELISA, whereas qualitative analysis was performed with SDS PAGE, two-dimensional electrophoresis, and western blotting. The results revealed a molecular heterogeneity in alpha1-AT, which can be classified into four patterns, a concentration-independent difference in alpha1-AT molecules found in the urine of patients and healthy subjects. A wider distribution of protein isoelectric points was found in urolithiasis (3.0-8.0) than in healthy subjects (4.0-5.0). We suggest that this new finding with molecular heterogeneity was due to the urolithiasis.
