engleski

Serum gangliosides in patients with brain tumors

Introduction: Gangliosides, lipid constituents of cell membranes, are involved in various significant processes such as cell growth, proliferation, differentiation, oncogenesis etc. Specific changes of gangliosides pattern in brain tumors reflecting tumor histopathological origin, malignancy and progression, have been extensively studied. Also, it has been observed that tumor cells of neuroectodermal origin may shed their gangliosides into circulation, resulting in higher ganglioside concentrations in serum. The aim of this study was to analyze gangliosides isolated from preoperative and postoperative sera of patients with brain tumors in order to determine possible differences in serum gangliosides content and composition before and after surgical removal of tumor. Materials & Methods: In this study, blood samples were collected from patients with glioblastoma (N=3), meningioma (N=3), acoustic neurinoma (N=1), haemangioma (N=1), oligodendroglioma (N=1) and astrocytoma (N=1), one week before and one week after surgical removal of the tumor. Gangliosides were extracted and purified from serum samples. Qualitative analysis was performed by high performance thin layer chromatographic (HPTLC) separation of individual gangliosides on silica gel plate. HPTLC plates with separated and visualized ganglioside fractions were analyzed by laser densitometry, enabling direct quantification of total and individual gangliosides in each sample. The concentrations of gangliosides were expressed as nanomoles of ganglioside-bound sialic acids (GG-SA) in mililiter of serum. Results: Quantitative analysis of serum gangliosides showed in average higher total gangliosides concentrations in preoperative sera comparing to postoperative sera. Approximately 2-fold decrease of ganglioside concentrations was observed in patients in which tumor was completely removed (meningioma, acoustic neurinoma, haemangioma). Interestingly, in the case of partial tumor removal (glioblastoma, astrocytoma, oligodendroglioma), concentrations of serum gangliosides increased postoperatively. Qualitative analysis of ganglioside pattern in sera showed the fractions migrating as GT1b, GD1a, GD3, GM2 and GM3. Several unknown minor fractions with migrating properties of disialoganglioside and monosialoganglioside structures were also observed. Comparison of ganglioside pattern in preoperative and postoperative serum samples did not reveal significant differences. However a postoperative decrease in GD3 proportion was observed in sera derived from patients with successful and complete tumor removal. Conclusions: Higher preoperative concentrations of serum gangliosides in patients with brain tumors are most probably a consequence of ganglioside release from tumor cells. Postoperative decrease of serum gangliosides may indicate successful outcome of a surgical treatment, thus representing an additional biochemical prognostic marker of brain tumors.

gangliosides; serum; brain tumors

Časopis je indeksiran u Neuroscience Citation indeksu i EMBASE/Excerpta Medica.