The isoform A of reticulon-4 (Nogo-A) in cerebrospinal fluid of primary brain tumor patients: influencing factors

// Olga Martyna Koper 1 , Joanna Kaminska 1 , Anna Milewska 2 , Karol Sawicki 3 , Zenon Mariak 3 , Halina Kemona 1 and Joanna Matowicka-Karna 1 1 Department of Clinical Laboratory Diagnostics, Medical University of Bialystok, Bialystok, Poland 2 Department of Statistics and Medical Informatics, Medical University of Bialystok, Bialystok, Poland 3 Department of Neurosurgery, Clinical Hospital of the Medical University of Bialystok, Bialystok, Poland Correspondence to: Olga Martyna Koper, email: o.koper@wp.pl Joanna Matowicka-Karna, email: matowic@umb.edu.pl Keywords: cerebrospinal fluid; isoform A of reticulon-4 (Nogo-A); primary brain tumor Received: August 24, 2017 Accepted: April 06, 2018 Published: May 18, 2018 ABSTRACT Background: The influence of isoform A of reticulon-4 (Nogo-A), also known as neurite outgrowth inhibitor, on primary brain tumor development was reported. Therefore the aim was the evaluation of Nogo-A concentrations in cerebrospinal fluid (CSF) and serum of brain tumor patients compared with non-tumoral individuals. Results: All serum results, except for two cases, obtained both in brain tumors and non-tumoral individuals, were below the lower limit of ELISA detection. Cerebrospinal fluid Nogo-A concentrations were significantly lower in primary brain tumor patients compared to non-tumoral individuals. The univariate linear regression analysis found that if white blood cell count increases by 1 × 10 3 /μL, the mean cerebrospinal fluid Nogo-A concentration value decreases 1.12 times. In the model of multiple linear regression analysis predictor variables influencing cerebrospinal fluid Nogo-A concentrations included: diagnosis, sex, and sodium level. The mean cerebrospinal fluid Nogo-A concentration value was 1.9 times higher for women in comparison to men. In the astrocytic brain tumor group higher sodium level occurs with lower cerebrospinal fluid Nogo-A concentrations. We found the opposite situation in non-tumoral individuals. Conclusions: Univariate linear regression analysis revealed, that cerebrospinal fluid Nogo-A concentrations change in relation to white blood cell count. In the created model of multiple linear regression analysis we found, that within predictor variables influencing CSF Nogo-A concentrations were diagnosis, sex, and sodium level. Results may be relevant to the search for cerebrospinal fluid biomarkers and potential therapeutic targets in primary brain tumor patients. Materials and methods: Nogo-A concentrations were tested by means of enzyme-linked immunosorbent assay (ELISA).