The astrocytic response towards invasive meningiomas
L Zeltner1, J Schittenhelm, M Mittelbronn
1Institute of Brain Research, University of Tübingen, Tübingen, Germany.
Abstract:
meningiomas disrupt the pial-glial basement membrane. This membrane is closely attached to the subpial glial endfeet forming the glia limitans. The fate of subpial astrocytes during the course of brain invasion by meningiomas is not known. In the present study we immunolabelled sections of 35 brain-invasive meningiomas (14 meningothelial meningiomas WHO grade I, 11 atypical WHO grade II and 10 anaplastic WHO grade III) using anti-collagen IV to label basement membrane material, and antibodies against astrocytic markers CD44, SPARC (secreted protein, acidic and rich in cysteine) and glial fibrillary acidic protein (GFAP). Astrocytes were present at the tumour-brain interface of 14/14 WHO grade I meningiomas, 9/11 WHO grade II tumours and 9/10 WHO grade III tumours. The presence of astrocytes was associated with an intact basement membrane in 11/14 WHO grade I meningiomas (P < 0.01), 6/9 WHO grade II tumours, and 6/9 WHO grade III tumours. However, tumour embedded in deep brain parenchyma lacked both an astrocytic reaction and basement membrane material. In conclusion, astrocytes eventually disappear from the tumour-brain interface during the course of meningioma infiltration. This observation might indicate that the survival of subpial astrocytes is dependent on an intact pial-glial basement membrane.
Insights
Subpial astrocytes disappear as brain-invasive meningiomas infiltrate, suggesting their survival depends on an intact pial-glial basement membrane. This study examined astrocyte presence and basement membrane integrity in various meningioma grades.
Area of Science:
- Neuroscience
- Oncology
- Cell Biology
Background:
- Meningiomas can invade brain tissue, disrupting the pial-glial basement membrane.
- The behavior of subpial astrocytes at the tumor-brain interface during invasion is not well understood.
Purpose of the Study:
- To investigate the fate of subpial astrocytes and the integrity of the basement membrane in brain-invasive meningiomas.
- To correlate astrocyte presence and basement membrane status with meningioma grade (WHO I, II, III).
Main Methods:
- Immunolabeling of 35 brain-invasive meningioma samples (WHO grades I, II, III).
- Used anti-collagen IV for basement membrane, and CD44, SPARC, GFAP for astrocytic markers.
- Analyzed astrocyte presence and basement membrane integrity at the tumor-brain interface and in deep brain parenchyma.
Main Results:
- Astrocytes were present at the tumor-brain interface in most meningiomas across all WHO grades.
- Astrocyte presence correlated with an intact basement membrane in lower-grade meningiomas.
- Meningiomas invading deep brain parenchyma lacked both astrocytes and basement membrane material.
Conclusions:
- Subpial astrocytes disappear from the tumor-brain interface during meningioma infiltration.
- The survival of subpial astrocytes may be dependent on an intact pial-glial basement membrane.
