Figure 2.

Summary of age-related neuroglial response(s) in the brain (hippocampus). The hippocampus is involved in the retrieval and consolidation of memory, and with advanced aging hippocampal function progressively deteriorates. These changes correlate with underlying hallmark neuroglial cell response, typified by the activation of microglial and astroglial cells, robust morphological changes, and an increase in phenotypic expression of antigen activation markers (MHCII, CD68, CD45, GFAP). In addition, activated neuroglial cells in aging also display increased production of pro-inflammatory cytokines and their signaling profiles, phagocytic/lysosomal activity, toxic oxidative-lipid products and a reduction in the production of anti-inflammatory cytokines and neurotrophic factors. In microglial cells, these changes are thought to contribute to their priming (and possible senescence), reducing their threshold of tolerability and therefore shifting the balance to increased age-related neuroinflammation and hence neurotoxicity. Astroglial cells, which are essential in metabolic support of neurons and vascular cells, progressively relinquish these supportive roles leading to deterioration in brain function. Together this culminates in subtle impairments in dendritic integrity, synaptic function, neurogenesis, increased oxidative metabolism, diminished protein clearance, and microvascular deterioration. Abbreviation: (ROS) reactive oxygen species such as nitric oxide, superoxide.