A review on urinary proteins in outflow disease of the upper urinary tract

INYRODUCTION: No review articles on outflow disease of the upper urinary tract discuss urinary protein excretion. DISCUSSION: Following acute partial and/or complete ureteral obstruction (UO) or chronic partial UO, alpha-1-microglobulin excretion is significantly higher than in the reference population or patients with proven renal dilatation without obstruction, but is not found to be diagnostic for these conditions as such. Chronic partial UO is followed first by a destructive and then by a steady-state phase in renal damage. The observed increase in tubular proteinuria during the destructive phase correlates with the decrease in absolute dimercaptosuccinic acid (DMSA) uptake. If the destructive phase is not followed by a stable phase, a mixed tubular and glomerular proteinuria is seen. Urinary alpha-1-microglobulin excretion is found to be diagnostically useful in vesico-ureteral reflux (VUR) patients, increases with higher intravesical-intrapyelic pressure, correlates with the decrease in absolute DMSA uptake or with urinary epidermal growth factor excretion (both markers of the number of functioning nephrons) and predicts the outcome after treatment. CONCLUSION: alpha-1-Microglobulin is useful in the detection of renal tubular damage in patients with outflow disease of the upper tract, is diagnostic for VUR but is not so for ureteral obstruction.