More on herpes simplex virus and Alzheimer's
Nearly all of us acquire herpes simplex virus at some point and then carry it. When we are young most of us can apparently control these infections more so than when we age. Some people, though, have recurrent outbreaks, usually as fever blisters, or for some, genital lesions. Some people with active virus show no outward symptoms at all. Reactivation of the virus produces inflammation in the brain. Most of the episodes are mild, but over time the effects could be cumulative. An infection such as this could explain why Alzheimer's begins in certain parts of the brain and eventually spreads to other areas. It could also explain the fluctuations that we often see in symptoms - when the virus is latent the person may do a little better, when there is a reactivation and greater inflammation, the person may get worse, a sort of two steps forward (worsening) and one step back (improvement) kind of process.
Steve has a long time history of lengthy outbreaks of fever blisters on his mouth, and had an outbreak around his eye and was quite sick at age 29. I strongly believe that, at least in his case, herpes simplex may be the cause of his Alzheimer's disease and this particularly bad episode could explain why he became symptomatic so early.
Now another group led by Dr. Nancy Sawtell at Cincinnati Children's Medical Center is providing more proof that herpes simplex may be the culprit for some people. She was inspired to do this work after Dr. Ruth Itzhaki visited her lab a few years ago. They have been working with mice in which the Apoe4 allele has been "knocked in" and infected them with the virus. They found that a lot more virus got into the brains of the Apoe4 mice than the non-Apoe4 mice. They are now trying to learn what makes some people more susceptible to the virus. She has found that the viral protein VP 16 is essential in triggering the virus's reactivation. So now they are trying to find substances that may inhibit VP 16 and therefore keep the virus from reactivating.
Dr. Itzhaki, in the meantime, is having difficulty getting funding for continuing her vital research. One skeptic on a review board can keep the board from approving a grant. I believe she and Dr. Sawtell are on the right path - their work needs to continue.