Multiple sclerosis is a chronic inflammatory disease with primary demyelination and neurodegeneration in the central nervous system. In our study we analysed demyelination and neurodegeneration in a large series of multiple sclerosis brains and provide a map that displays the frequency of different brain areas to be affected by these processes. Demyelination in the cerebral cortex was related to inflammatory infiltrates in the meninges, which was pronounced in invaginations of the brain surface (sulci) and possibly promoted by low flow of the cerebrospinal fluid in these areas. Focal demyelinated lesions in the white matter occurred at sites with high venous density and additionally accumulated in watershed areas of low arterial blood supply. Two different patterns of neurodegeneration in the cortex were identified:oxidative injury of cortical neurons and retrograde neurodegeneration due to axonal injury in the white matter. While oxidative injury was related to the inflammatory process in the meninges and pronounced in actively demyelinating cortical lesions, retrograde degeneration was mainly related to demyelinated lesions and axonal loss in the white matter. Our data show that accumulation of lesions and neurodegeneration in the multiple sclerosis brain does not affect all brain regions equally and provides the pathological basis for the selection of brain areas for monitoring regional injury and atrophy development in future magnetic resonance imaging studies.
In our study they analysed predilection sites of demyelination and neurodegeneration and how these relate to arterial and venous anatomy and inflammation or demyelination in multiple sclerosis.
Where are the lesions located?
Around the ventricles and around the cortex and in the sulci.
Areas with a high venous density are likely to harbour demyelinated white matter lesions, but not all brain areas with high venous density are equally affected. This is because the damaging cells enter the CNS via venules/vein. It is not because of blocked veins
In this study they distinguished between two different patterns of neurodegeneration. The first was oxidative injury and is a problem leading to energy problems for nerves.The second pattern of neuronal pathology represented retrograde neurodegeneration.