[Correlative study of distribution of brain tumor stem cell with micro-vascular system]

To investigate the expressions of putative brain tumor stem cell (BTSC) marker CD133, Nestin and blood vessel endothelial cell marker CD31 in 65 cases of formalin fixed paraffin embedded gliomas. The relationship of BTSC distribution with micro-blood vessels was analyzed using morphometry.

(1) The expression levels of Nestin and CD133 proteins were detected using SABC immunohistochemical analysis. Then we calculated the percentage of CD133(+) cells, CD133(+) blood vessels, Nestin(+) cells and Nestin(+) blood vessels among 65 tumors, grade II (n = 18), grade III (n = 23) and grade IV (n = 24), according to WHO 2000 classification of nervous system tumors. (2) Double immunofluorescence staining was used to detect the co-expressions of CD133/CD31, CD133/Nestin and Nestin/CD31. Then the correlation of two different marked cells with the corresponding positive vascular endothelial cells were determined.

CD133(+) cells and Nestin(+) cells could be observed in all glioma tissues. Furthermore they could also be observed expressing in the endothelial cells. In low-grade group, there were fewer CD133(+) blood vessels or Nestin(+) blood vessels in the regions which CD133(+)cells or Nestin(+) cells distributed compared with the high-grade group. The CD133(+)/CD31(+) and Nestin(+)/CD31(+) cells could be found co-expressed in the endothelial cells by using double immunofluorescence staining. Positive correlation was observed between the CD133(+) cells and CD133(+) blood vessels (r = 0.945, P < 0.01). It was similar to the correlation between the Nestin(+) blood vessels and Nestin(+) cells (r = 0.727, P < 0.01).

In gliomas, the endothelial cells express brain tumor stem cells markers. Therefore the capillaries in gliomas may come from the differentiation of BTSCs. And the BTSCs are accumulated around the capillaries. Along with the rank of tumor grades, positive correlation is observed between CD133(+) cells or Nestin(+) cells with the corresponding blood vessels.