Urinary RBP is a type of low-molecular protein existing in the blood, and research has found that the elevated excretion can sensitively reflect the damage degree of renal proximal tubule.
In normal healthy persons, the content of urinary RBP is very small, while in a lot of diseases, such as Diabetes, high blood pressure(High Blood Pressure and Kidney Disease), Lupus Erythematosus, and urinary infection, urinary RBP could also sensitively the damage of renal tubule in these diseases.
Urinary RBP is stable and not easy to destroy in the urine acid environment, and moreover, it is more superior than the traditional markers, such as β-2 Microglulin(β-2 MG) and micro-albumin(Malb), so it has vital clinical values in the assessment of early damages of renal tubule’ function in such diseases as Diabetes, high blood pressure, and Immunotherapyatic lupus erythematosus(SLE).
Urine NAG is contained mainly in the kidneys, especially in the epithelial cells of proximal tubule. Due to it is a high-molecular protein, so serum NAG cannot get through the glomerular membrane, thereby, the urine NAG mainly come from the lysosome of the proximal tubule. The elevation of the urine NAG is a sensitive marker with strong specificity.
The significance of the detection of elevated urine NAG includes many aspects: 1. Early detection for kidney damage caused by some medications; 2. Location diagnosis for the urinary infection, that is to say, urine NAG increases when there are some kidney infections or inflammations, or renal tubule diseases; 3. Detection of rejection responses caused by kidney transplant.
Urine GGT is similar to urine NAG in many aspects, the only point that we need to pay attention to is that urine GGT would not increase in the disease of Chronic Nephritis, while in Acute Glomerular Nephritis or Lupus Nephritis, urine GGT could increase.
From the above, we can see that whether urinary RBP, or urine enzymes such as NAG, GGT, both of which could effectively reflect the damage in the part of kidney tubule.
