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Matrix metalloproteinases-9 and -2 in secondary vasculitic neuropathies
Susanne Renaud1, Beat Erne, Peter Fuhr
1Department of Neurology, University Hospitals, Petersgraben 4, 4031 Basel, Switzerland.
Abstract:
Matrix metalloproteinases (MMPs) are a family of zinc-dependent endoproteinases that play an important role in inflammation and tissue degradation. MMP-9 and MMP-2 are gelatinases that have been implicated in the degradation of the blood-brain or blood-nerve barrier. We present an immunohistochemical study on 11 nerve biopsy samples of inflammatory and non-inflammatory polyneuropathies. Perineurium and endothelium were positive for MMP-2 in all tissue sections. In addition, there was a specific up-regulation of MMP-2 in stromal cells of chronic inflammatory demyelinating polyneuropathy (CIDP) and even more in vasculitic neuropathies. MMP-9-positive cells were detected in vessel walls, infiltrates, epineurium and endoneurium of vasculitic neuropathies. In CIDP, MMP-9-positive cells were prominent in vessel walls. Only a few MMP-9-positive cells were detected in noninflammatory controls in blood vessels and adhering to vessel walls. Double staining indicated that the infiltrating cells were T cells and macrophages. Our findings suggest that MMP-9 plays an important role in inflammatory peripheral neuropathy probably as means for inflammatory cell invasion.
Insights
Matrix metalloproteinases (MMPs), specifically MMP-9 and MMP-2, are implicated in peripheral nerve inflammation. This study found MMP-9 is crucial for inflammatory cell invasion in neuropathies.
Area of Science:
- Neuroscience
- Immunology
- Biochemistry
Background:
- Matrix metalloproteinases (MMPs) are enzymes involved in tissue degradation and inflammation.
- MMP-2 and MMP-9 are gelatinases linked to the breakdown of protective barriers, including the blood-nerve barrier.
Purpose of the Study:
- To investigate the role of MMP-2 and MMP-9 in inflammatory and non-inflammatory peripheral neuropathies using immunohistochemistry.
- To determine the specific localization and cellular expression of MMP-2 and MMP-9 in nerve biopsy samples.
Main Methods:
- Immunohistochemical analysis of 11 nerve biopsy samples from patients with polyneuropathies.
- Detection and localization of MMP-2 and MMP-9 expression in perineurium, endothelium, stromal cells, and infiltrating immune cells.
- Double staining to identify the cell types expressing MMP-9, including T cells and macrophages.
Main Results:
- MMP-2 was consistently found in perineurium and endothelium across all samples.
- MMP-2 showed increased expression in stromal cells of chronic inflammatory demyelinating polyneuropathy (CIDP) and vasculitic neuropathies.
- MMP-9-positive cells, identified as T cells and macrophages, were significantly elevated in vessel walls, infiltrates, and nerve tissues of vasculitic neuropathies and CIDP compared to controls.
Conclusions:
- MMP-2 is broadly expressed in nerve tissue, with enhanced stromal cell expression in inflammatory conditions.
- MMP-9 plays a significant role in inflammatory peripheral neuropathies, likely facilitating inflammatory cell infiltration into nerve tissues.
- Targeting MMP-9 may offer a therapeutic strategy for managing inflammatory peripheral neuropathies.