Optical detection of plasma chitotriosidase activity in healthy Chinese children using fluorescence spectrophotometry

Plasma chitotriosidase had been proposed as a biochemical marker of macrophage accumulation in several lysosomal storage disorders. The selection of wavelength and possible interferences and errors have not yet been explored in the assay of chitotriosidase activity. We evaluated the feasibility of measurement of plasma chitotriosidase activity by fluorescence spectrophotometry and established pediatric reference values for earlier diagnosis of related diseases.

We assayed plasma chitotriosidase activity in 104 healthy Chinese children by a fluorometric approach which combines 3-dimension scan spectra, wavelength scan spectra, time scan spectra and fluorescence intensity analysis.

The optimal excitation wavelength and emission wavelength were 358 and 448 nm, respectively. A change of enzyme activity over time was observed fluorometrically, The reference value was 13.04+/-4.94 nmol/ml/h (12.45+/-4.37 nmol/ml/h for boys and 14.04+/-3.99 nmol/ml/h for girls).

We present an integrated application of the fluorescence spectrophotometry as an ideal tool to determine enzymatic activity with 4-methylumbelliferyl triacetylchitotrioside as labeled substrates in clinical laboratory. The function of 3D scan was proved powerful in determination of plasma chitotriosidase activity. The establishment of plasma chitotriosidase activity reference pediatric values was potentially useful for the evaluation of all related diseases.