Abstract
Purpose: :
N-acetyl aspartate (NAA) is an amino acid present in high concentrations in neurons and is thus a putative neuronal marker. In vivo proton magnetic resonance spectroscopy (H-MRS) studies have shown lower NAA concentrations in patients with various neurodegenerative disorders (Alzheimer, schizophrenia). Recently has been developed a method to measure the serum levels of NAA, as a marker of central neuronal loss, making it possible to detect indirectly neurological diseases by means of the increase of serological levels of NAA. This method was applied to detect the retinal neuronal loss in glaucomatous patients.
Methods: :
the study was performed on glaucomatous patients aging 45 to 65 y, and with perimetric Mean Defect (MD) between -5 and -25 dB; normal subjects age and sex-matched were also recruited as controls. All the subjects selected hadn’t any present or previous neurological diseases. NAA was determined using "combined gas chromatography-mass spectrometry" (GC/MS) on fresh whole blood samples, taken from the antecubital vein.
Results: :
10 normal subjects(6M/4F) and 30 glaucoma patients(21M/9F) were recruited. In the group of glaucomatous patients the distribution of NAA showed a range of variation between 68 to 204 (median 93,5) mmol/L, while in the control group the distribution range was 24 to 76 (median 35,5) mmol/L (p<0.001).
Conclusions: :
these preliminary data suggest that NAA blood levels are increased in glaucomatous patients with perimetric damage. This finding could represent decreased neuronal density or neuronal dysfunction as well as in other neurodegenerative pathologies.
Keywords: clinical laboratory testing • optic nerve • ganglion cells