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J J G Geurts

Publications and source records attributed to J J G Geurts.

6 recordsLinked to original sources
PubMed2006

Grey matter pathology in multiple sclerosis.

Although multiple sclerosis (MS) has been considered a white matter disease, MS lesions are known to occur in grey matter. Recent immunohistochemical studies have demonstrated extensive grey matter demyelination in chronic MS. The most common lesion type consists of purely cortical lesions extending inward from the surface of the brain, this lesion subgroup is grossly underestimated by standard histochemical myelin staining methods. Some MS patients have subpial demyelination in all cortical areas of the brain; this pattern has been termed ''general cortical subpial demyelination''. Extensive cortical demyelination is associated with the progressive phases of disease, as less cortical demyelination has been detected in relapsing-remitting MS. The pathology of grey matter lesions differs from that of white matter lesions; grey matter lesions are less inflammatory, with less macrophage and lymphocyte infiltration. In purely cortical lesions there is no significant increase in lymphocytes compared with non-demyelinated adjacent cortical areas in MS patients or cerebral cortex in control patients. Significant axonal transection and neuronal loss have been demonstrated in grey matter MS lesions. Current magnetic resonance imaging (MRI) methods are not sensitive for purely cortical MS lesions. The clinical significance of cortical MS lesions may not be characterised until more sensitive MRI methods are developed.

Cerebral Cortex↗
PubMed2006

Normal-appearing white matter changes vary with distance to lesions in multiple sclerosis.

BACKGROUND AND PURPOSE: Multiple sclerosis (MS) disease processes in normal-appearing white matter (NAWM) may be different close to MR-visible lesions than farther from these lesions. We aimed to investigate the relationship of NAWM changes to the distance to the lesions. METHODS: We measured B(1)-corrected T1 and magnetization transfer ratio (MTR) maps in 63 patients with MS (11 primary progressive, 34 relapsing-remitting, 18 secondary progressive). We used histogram analyses to assess the global properties of lesions, of 4 consecutive 1-mm pixel layers of NAWM around the lesions, and of distant NAWM located at least 4-mm from lesions in all directions. In 22 healthy controls, we measured white matter MTR and T1 histograms. Histogram parameters were statistically analyzed by using a linear mixed model. RESULTS: The first and second NAWM pixel layers around the lesions had a significantly lower MTR histogram peak position than distant NAWM, whereas T1 histogram peak position was similar between all types of NAWM. Furthermore, MTR histograms of distant NAWM were statistically indistinguishable from those of control white matter, whereas T1 histograms of distant NAWM had significantly decreased peak height for relapsing-remitting MS and secondary progressive MS and significantly increased peak position for secondary progressive MS. CONCLUSION: Our results may suggest that axonal damage and demyelination in NAWM mainly arise as a secondary result of visible lesions, with the largest effect close to these lesions. NAWM disease farther from the lesions may be mainly characterized by subtle blood-brain barrier damage, with leakage of fibrinogen into the parenchyma and microplaque formation, processes that are detected with T1 but not with MTR.

Adult↗
PubMed2005

Expression patterns of Group III metabotropic glutamate receptors mGluR4 and mGluR8 in multiple sclerosis lesions.

Recent evidence supports a role for metabotropic glutamate receptors (mGluRs) in neuroinflammatory diseases. In the present study, we have investigated whether the group III mGluR subtypes mGluR4 and mGluR8 are expressed in MS lesions at various stages of evolution. In control patient tissue and in normal-appearing MS white matter (NAWM), no microglial or astrocyte staining was detected. In contrast, in active lesions, mGluR8 immunoreactivity (IR) was detected in cells of the microglia/macrophage lineage. Fewer macrophage-like cells were positive for mGluR8 in chronic active and inactive lesions. No mGluR4 IR was detected in cells of the microglia/macrophage lineage in the MS lesions studied. In chronic active lesions, however, a population of reactive astrocytes localized in the rim of the lesions expressed both mGluR4 and mGluR8. Our results suggest a role for these receptor subtypes in the inflammatory response in MS that involves both astrocytes and cells of the microglia/macrophage lineage.

Brain↗
PubMed2004

Magnetic resonance imaging as a tool to examine the neuropathology of multiple sclerosis.

Magnetic resonance imaging (MRI) has significantly extended the understanding of multiple sclerosis (MS), owing to its ability to sensitively depict the dynamics of the disease process in vivo. The subject of this review is the use of MRI in the post-mortem setting, with emphasis on how it may be used to improve the specimen selection process at autopsy. Lesions with active demyelination are highly interesting in the study of MS pathogenesis, but are rare in a typical autopsy material of chronic MS. The yield of MS lesions in autopsy specimen selection can be increased by the use of MRI-guided tissue sampling, as a significant proportion of abnormalities detected by post-mortem MRI are not macroscopically visible/palpable. The majority of these MRI abnormalities have been found to represent either discrete areas of microglial activation with no demyelination (so-called (p)reactive lesions), or active demyelinating MS lesions by further histopathological examination. The presence and extent of MS pathology outside of the focal demyelinated lesions is more readily appreciated by MRI-guided specimen sampling, as has been shown in the study of extensive areas of partial myelin loss in the spinal cord. A further advantage of MRI-guided specimen sampling is the ability to use three-dimensional and quantitative measures. The potential of correlating these with histopathological data may be further exploited in the future. The technical procedure for MRI-guided tissue sampling at autopsy is presented, and the limitations of the technique are discussed.

Autopsy↗
PubMed2003

Altered expression patterns of group I and II metabotropic glutamate receptors in multiple sclerosis.

Recent evidence supports a role for glutamate receptors in the pathophysiology of multiple sclerosis. In the present study, we have focused specifically on the expression of metabotropic glutamate receptors (mGluRs) in multiple sclerosis brain tissue. The expression of group I (mGluR1alpha and mGluR5) and group II (mGluR2/3) mGluRs was studied using immunohistochemistry in tissue from 12 multiple sclerosis cases and seven non-neurological controls. The expression patterns of both group I and II mGluRs in multiple sclerosis tissue differed significantly from those in control tissue. Strong mGluR1alpha immunoreactivity was observed in axons of the subcortical white matter, particularly in the centre of actively demyelinating lesions and in the borders of chronic active lesions. mGluR1alpha axonal immunopositivity was also found in normal appearing multiple sclerosis white matter, but axons in control white matter were generally negative. mGluR1alpha axonal labelling was associated with the presence of non-phosphorylated neurofilaments and beta-amyloid precursor protein, which are sensitive markers for axonal injury and disturbed axonal transport. Changes in mGluR immunoreactivity were also observed in glia. A diffuse increase in the expression of mGluR5 and mGluR2/3 was detected in reactive astrocytes in multiple sclerosis lesions. However, only a subpopulation of reactive astroglial cells expressed mGluR1alpha. In addition, labelling with antibodies to mGluR2/3 and, to a lesser extent labelling with antibodies to mGluR1alpha, was detected in a population of cells of the microglial/macrophage lineage that displayed a macrophage-like morphology. Our data suggest that mGluRs, like ionotropic glutamate receptors, play a role in the complex processes that are associated with the progressive brain damage in multiple sclerosis, including both glial activation and pathological changes in axons.

Adult↗