The interaction between brain ischemia and Alzheimer’s disease (AD) has been intensively investigated recently. Nevertheless, we have not yet understood the nature and mechanisms of the ischemic episodes triggering the onset of AD and how they influence its slow progression. The assumed connection between brain ischemia and the accumulation of amyloid-β (Aβ) peptide awaits to be clearly explained. In our research, we employed a rat cardiac arrest model to study the changes in gene expression of amyloid-β protein precursor (AβPP) and its cleaving enzymes, β- and γ -secretases (including presenilins) in hippocampal CA1 sector, following transient 10-min global brain ischemia. The quantitative reverse-transcriptase PCR assay demonstrated that the expression of all above genes that contribute to Aβ peptide generation was dysregulated during 30 days in postischemic hippocampal CA1 area. It suggests that studied Aβ peptide generation-related genes can be involved in AβPP metabolism, following global brain ischemia and will be useful to identify the molecular mechanisms underpinning that cerebral ischemia might be an etiological cause of AD via dysregulation of AβPP and its cleaving enzymes, β- and γ -secretases genes, and subsequently, it may increase Aβ peptide production and promote the gradual and slow development of AD neuropathology. Our data demonstrate that brain ischemia activates delayed neuronal death in hippocampus in an AβPP-dependent manner, thus defining a new and important mode of ischemic cell death.
Introduction and objective: Using the concepts of Ulrich’s theory of supportive design and Malkin’s healing environment, an eye tracking experiment was designed in order to measure respondents’ reactions while looking at visualisations of various interiors, with the aim of verifying...
Understanding the mechanisms underlying the selective susceptibility to ischemia of the CA3 region is very important to explain the neuropathology of memory loss after brain ischemia. We used a rat model to study changes in gene expression of the amyloid protein precursor and its cleaving enzymes and tau protein in the hippocampal CA3 sector, after transient 10-min global brain ischemia with survival times of 2, 7, and 30 days. The expression of the α-secretase gene was below control values at all times studied. But, the expression of the β-secretase gene was below the control values at 2–7 days after ischemia and the maximal increase in its expression was observed on day 30. Expression of the presenilin 1 gene was significantly elevated above the control values at 2–7 days after ischemia and decreased below the control values at day 30. Expression of the presenilin 2 gene showed an opposite trend to the expression of presenilin 1. Expression of the amyloid protein precursor gene after ischemia was at all times above the control values with a huge significant overexpression on day 7. Additionally, the expression of the tau protein gene was below the control values 2 days after ischemia, but the significant increase in its expression was observed on days 7–30. Data show that brain ischemia activates neuronal changes and death in the CA3 region of the hippocampus in a manner dependent on amyloid and tau protein, thus determining a new and important way to regulate the survival and/or death of ischemic neurons.
These authors contributed equally to this work. These authors are co-senior authors. Ischemic brain damage is a pathological incident that is often linked with medial temporal lobe cortex injury and finally its atrophy. Post-ischemic brain injury ass