I think its important to mention that the particulars of memory storage in the brain are still being worked out. I think what we do know about it is that memory storage depends a lot on the physical configuration of the neurons in the brain. They move about and make new connections as they process information (and probably also when they are not processing information!). Different regions of the brain store short vs long term memory and different sorts of memories. They neurons themselves have a lot of internal cell physiology that can change as well - there are many different neuroreceptors that constitute the synaptic junctions.
All these things may not be a comprehensive list. But at the basis of all these processes, the cell expresses new proteins in mRNA and these proteins are doing all this work. beta-actin and histone de-acetylase, as mentioned in your link, are responsible for the cell rearranging itself in the cell shape and in terms of its internal transport processes and in the nucleus respectively.
I'm pretty sure that exactly what is happening here is not really well understood. monitoring the interior of the cell is difficult. The work where histone deacetylase is inhibited is a fresh new thought, showing that the arrangement of the chromosomes in the nucleus is involved in hiding memories. Its still the equivalent to getting a stopped watch to start again by shaking it - there are parts there that fell into place and started ticking again, but we don't really know what the parts are doing in any detail yet.
This hints that if you were to disrupt the cells in some ways you might be able to free up memory, but its a long way from guaranteeing that any given approach will work. I'd be surprised even if Dr Tsai's cell treatment worked even 70% of the time in her experiment. Hypnosis or a focused meditation session might still be just as effective. I think that its a bit too much to expect that Alzheimer's memories are completely preserved and recoverable. In some cases probably, but categorical statements rarely hold in bioscience.
Like a lot of neuroscience, this work is suggestive, but still just progress towards a clearer understanding of these processes.