Can Toxoplasma gondii Pave the Road for Dementia?

ABSTRACT: Dementia is an ominous neurological disease. Scientists proposed a link between its occurrence and the presence of Toxoplasma gondii (T. gondii). The long-term sequels of anti-Toxoplasma premunition, chiefly dominated by TNF-?, on the neurons and their receptors as the insulin-like growth factor-1 receptor (IGF-1R), which is tangled in cognition and synaptic plasticity, are still not clear. IGF-1R mediates its action via IGF-1, and its depletion is incorporated in the pathogenesis of dementia. The activated TNF-? signaling pathway induces NF-?? that may induce or inhibit neurogenesis. This study speculates the potential impact of anti-Toxoplasma immune response on the expression of IGF-1R in chronic cerebral toxoplasmosis. The distributive pattern of T. gondii cysts was studied in association with TNF-? serum levels, the in situ expression of NF-??, and IGF-1R in mice using the low virulent ME-49 T. gondii strain. There was an elevation of the TNF-? serum level (p value ? 0.004) and significant upsurge in NF-?? whereas IGF-1R was of low abundance (p value < 0.05) compared to the controls. TNF-? had a strong positive correlation with the intracerebral expression of NF-?? (r value ? 0.943, p value ? 0.005) and a strong negative correlation to IGF-1R (r value -0.584 and -0.725 for area% and O.D., respectively). This activated TNF-?/NF-?? keeps T. gondii under control at the expense of IGF-1R expression, depriving neurons of the effect of IGF-1, the receptor's ligand. We therefore deduce that T. gondii immunopathological reaction may be a road paver for developing dementia.

SUBMITTER: El Saftawy EA 

PROVIDER: S-EPMC7414348 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature