Neuroinflammatory penumbra in Parkinson’s disease

To date, the etiology and pathogenesis of Parkinson’s disease (PD) are not fully understood. In this publication, we present a critical review of the available international data on the involvement of inflammation processes in the etiopathogenesis of the disease in the context of our research results. The data obtained by us during modeling of parkinsonian syndrome of neuroinflammatory origin (lipopolysaccharide endotoxin was used) in laboratory rats (basic group, n = 21; control group, n = 7) indicate that intranasal administration of lipopolysaccharide in all three studied doses (1, 10 and 100 μg/kg/ml) seven days after the end of the experiment (21 injections) causes the same moderate morphological degenerative and inflammatory changes in the histostructure of the substantia nigra, extending to the striatum area (p > 0.05). This fact can be best explained by the all-or-none law. The staged, sequential transition of primary reversible (neuroinflammatory) pathomorphological changes to secondary irreversible (neurodegenerative) ones in PD, as well as secondary activation of microglia during neuronal degeneration, allows proposing the term “neuroinflammatory penumbra”, which will best help understand the pathogenesis of the disease and the development of therapies that change the course of Parkinson’s disease. Our data on the use of mesenchymal multipotent stromal cells in rats with neurotoxic (rotenone) parkinsonian syndrome (n = 10) and in PD individuals (n = 10) demonstrate a decrease in motor impairment, overall improvement of patients and an effect on laboratory parameters compared with control groups. We associate the early positive effect, observed already in the first week after the administration of mesenchymal multipotent stromal cells, with their paracrine action, including on the neuroinflammatory penumbra.