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Figure 2 mTORC1 activation, neuronal quantity and gliosis. A. - D. mTOR activation was present in all cortical tuber types as well as in perituberal cortex (pS6-Ser235/236 staining). E. Gradient mTOR activation among the tuber types. F. - I. Loss in neuronal cell density could be observed in type B tubers (NeuN staining). J. Neurons were significantly depleted (p= 0.015). K. - N. Gli- osis was present in all tuber types (GFAP staining). O. Increase of gliosis reached significance (p=0.019). Scale bar in D, I, and N = 100μm and applies also to F, G, H, K, L, and M. CO = control; PT = perituberal cortex.
The inter-observer agreement was very good (κ= 0.973).
The following quantitative analysis was based on 28 available tuber specimens.
Subsequently, our cohort consisted of 7 type A tubers (median age= 10.00 years, range 3-47 years; 6 males, 1 females; 5 frontal, 2 temporal), 13 type B tubers (median age= 7 years, range 0.83-22 years; 6 males, 7 females; 4 frontal, 6 temporal, 2 parietal, 1 hemi- spheric) and 8 type C tubers (median age= 3 years, range 1-6 years; 5 males, 3 females; 7 frontal, 1 parietal).
mTORC1 activation, neuronal quantity and gliosis
In our cohort we compared with histologically normal cortex to clarify the role of perituberal cortex. Independent-sample Kruskal-Wallis testing revealed no differences in mTORC1 activation among the tuber types and perilesional samples (Fig. 2 A-E). However, mTORC1 activation was significantly increased in all samples compared to con- trols (H[4]= 22.942, p= 0.000). Interestingly, in the distribution of NeuN positive cells/ mm2 varied significantly among the subgroups (H[3]= 10.416, p= 0.015; median and range of all quantification data see Table 1). However, subsequent pairwise comparison did not reveal significant changes. We could however observe a tendency in type B tubers to show decreased neuronal cell counts (Fig. 2 F-J). Quantification of GFAP positivity revealed a variation in distribution among the groups (H[3]= 9.943, p= 0.019; Table 1). Pairwise comparison showed a significant increase of GFAP density in type B tubers when compared to perituberal samples (p= 0.023). All calculations were based upon