Detectable concentrations of urinary trypsin inhibitor in cerebrospinal fluid

Urinary trypsin inhibitor (UTI) is a physiological protease inhibitor produced in the liver and excreted into urine. Urinary trypsin inhibitor-like antigen has been demonstrated on glial cells in the brain. This study measured cerebrospinal UTI levels in various conditions. Seven subjects in each of the following groups were studied: patients undergoing spinal anesthesia for minor surgery, spinal anesthesia for cesarean section, removal of meningioma, or at postoperative day 3 after ruptured intracranial aneurysm clipping. Cerebrospinal fluid was collected from a spinal needle, a needle puncturing the sylvian fissure, or a drainage tube from the optical carotid cistern. Urine was collected from a urinary catheter. Cerebrospinal and urinary UTI concentrations were measured by radioimmunoassay, and the urinary UTI concentration was divided by urinary creatinine concentration to give the systemic UTI concentration. The cerebrospinal UTI concentration in the brain tumor and postoperative state groups was significantly higher than in the spinal anesthesia and cesarean section groups. The systemic UTI concentration in the cesarean section and postoperative state groups was significantly higher than in the spinal anesthesia and brain tumor groups. The present results demonstrate that UTI can be detected in the cerebrospinal fluid, and suggest that cerebrospinal UTI increases in patients with a brain tumor or inflammation and is not affected by systemic UTI.