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Microbes & Immunity Characterizing low-grade CNS tumors

with mild midline shift and compression effects. MRS angiogenic potential of these tumors through VEGFR2-
indicated increased choline and predominantly reduced targeted immunofluorescence using TRITC-conjugated
NAA levels. Intracranial diffuse astrocytoma (Figure 1I) antibodies. Qualitative examination revealed enhanced
demonstrated an ill-marginated region of altered signal neovascularization in astrocytoma (Figure 2N)
intensity in the left temporo-parietal region, appearing compared to meningioma (Figure 2M) and spinal
hypointense on T1 and hyperintense on T2-weighted ependymoma (Figure 2L). Quantitative analysis of MFI
images. The lesion was associated with a distinct mass values demonstrated statistically significant differences:
effect and midline shift. MRS showed highly elevated astrocytoma (59.66 ± 2.55), ependymoma (30.10 ± 2.38),
choline levels and significantly reduced NAA peaks. and meningioma (21.35 ± 2.35) (Figure 2O).
Across all tumor types, consistently increased choline and These findings collectively indicate a progressive
reduced NAA levels reflected altered cellular metabolism increase in angiogenic activity that correlates with the
characteristic of neoplastic transformation. Among these, observed proliferative indices. This suggests a coordinated
astrocytoma displayed the most pronounced metabolic upregulation of both proliferative and angiogenic signaling
disruption, consistent with its higher malignant potential.
pathways in astrocytoma, distinguishing it from other low-
GFAP immunofluorescence revealed extensive grade CNS tumor types.
astrocytic involvement in low-grade astrocytoma
(Figure 1L), with numerous GFAP-positive cells indicating 3.3. MMP-2 expression and invasive potential in
glial hypercellularity. Spinal ependymoma exhibited low-grade tumor types
significantly fewer GFAP-positive cells (Figure 1D), while Flow cytometric analysis revealed that the MFI of
meningioma demonstrated minimal GFAP expression MMP-2-PE was highest in ependymoma (Figure 3A),
(Figure 1H), consistent with its origin from GFAP-negative followed by astrocytoma (Figure 3C), and with the
meningio-epithelial cells. lowest expression observed in meningioma (Figure 3B).
To further assess gelatinase-dependent invasiveness, we
3.2. Immunocytochemistry and immunofluorescence conducted immunofluorescence using MMP-2-FITC.
assay corroborates cell-cycle, proliferation, and
neo-angiogenesis Ependymoma (Figure 3D) exhibited intense, regionally
clustered MMP-2 expression, in contrast to the sparse and
Immunohistochemical analysis of Ki-67 expression scattered signal in meningioma (Figure 3E) and the diffuse
revealed distinct proliferative profiles among the three moderate expression pattern in astrocytoma (Figure 3F).
tumor types. Astrocytoma demonstrated the highest Ki-67 Quantitative analysis of MFI values showed statistically
expression (Figure 2C), whereas ependymoma (Figure 2A) significant differences in MMP-2 expression across tumor
and meningioma (Figure 2B) exhibited comparatively types (Figure 3G). Notably, ependymoma, despite its lower
lower expression. Quantitative assessment of Ki-67- proliferative index, demonstrated the highest MMP-2
positive cell indices yielded mean values of 0.62 ± 0.09 for expression (62.03 ± 9.50), followed by astrocytoma
ependymoma, 1.34 ± 0.36 for meningioma, and 2.1 ± 0.16 (40.90 ± 2.04) and meningioma (21.30 ± 2.62).
for astrocytoma. Statistical analysis confirmed significant
differences in proliferative indices across all tumor These findings suggest an inverse relationship between
types, with the most marked disparity observed between proliferative activity and MMP-2-mediated invasive
ependymoma and astrocytoma (Figure 2D). potential, with ependymomas demonstrating the highest
gelatinase-dependent invasiveness despite limited
Flow cytometric analysis using PI staining corroborated proliferation. This observation highlights ependymomas as
the Ki-67 findings. Cell cycle distribution analysis a potentially underexplored therapeutic target for MMP-2
demonstrated that astrocytoma exhibited the highest inhibitors. Furthermore, profiling MMP-2 expression
percentage of cells in active proliferative phases (S+G2/M: may serve as a diagnostic tool for personalized treatment
20.40 ± 2.06%) (Figure 2I and 2J), followed by meningioma strategies for low-grade CNS tumors.
(S+G2/M: 12.60 ± 0.70%) (Figure 2G and 2H) and
ependymoma (S+G2/M: 8.63 ± 0.51%) (Figure 2E and 2F). 3.4. Immune cell infiltration profiles in the studied
Comparative analysis revealed statistically significant low-grade CNS tumors based on silver-gold staining,
differences, confirming that astrocytoma displayed CD11b, and Iba1 expression
markedly elevated proliferative activity relative to the other SG histochemical staining was employed to visualize
two tumor types (Figure 2K). electron-dense mononuclear immune cell populations
Given that neoangiogenesis represents a fundamental within the tumor microenvironment, leveraging the
hallmark of malignancy, we further assessed the differential affinity of metallic ions for cytoplasmic

Volume 2 Issue 3 (2025) 135 doi: 10.36922/MI025190040