Wyss-Coray’s group identified changes in the hippocampus, a structure key for forming certain types of memories, notably the recollection and recognition of spatial patterns. Both experience and aging modulate hippocampal activity and anatomy; veteran London cabdrivers have a larger than average hippocampus while normal aging deteriorates the hippocampus. In Alzheimer’s disease, this hippocampal deterioration is accelerated, leading to an inability to form new memories. When researchers compared hippocampi from old mice who received the young mice plasma with those from old mice that had received plasma from other old mice, they found consistent differences in a number of biochemical, anatomical and electrophysiological measures known to be important to nerve-cell circuits’ encoding of new experiences for retention in the cerebral cortex. It is unclear what factors present in the blood from young mice caused these changes or if similar results will occur in humans. However, in the future these results may mean new therapeutic approaches for treating Alzheimer’s disease and other aged-associated cognitive disorders.
Tuesday, July 8, 2014
How a blood transfusion may one day recharge your brain
Wyss-Coray’s group identified changes in the hippocampus, a structure key for forming certain types of memories, notably the recollection and recognition of spatial patterns. Both experience and aging modulate hippocampal activity and anatomy; veteran London cabdrivers have a larger than average hippocampus while normal aging deteriorates the hippocampus. In Alzheimer’s disease, this hippocampal deterioration is accelerated, leading to an inability to form new memories. When researchers compared hippocampi from old mice who received the young mice plasma with those from old mice that had received plasma from other old mice, they found consistent differences in a number of biochemical, anatomical and electrophysiological measures known to be important to nerve-cell circuits’ encoding of new experiences for retention in the cerebral cortex. It is unclear what factors present in the blood from young mice caused these changes or if similar results will occur in humans. However, in the future these results may mean new therapeutic approaches for treating Alzheimer’s disease and other aged-associated cognitive disorders.
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Speculation...
ReplyDeleteOne could speculate that metabolic factors are at play in the hippocampal regeneration in treated animals. From what I understand neurons receive metabolic support from oligodendrocytes which are the blood brain barrier. Is it possible that plasma from young animals provides oligodendrocytes with more and higher quality metabolic precursors? If so this may enable oligodendrocytes to more adequately support their neurons.
Thoughts?
Austin, I think you raise an interesting speculation on dosing mice with glial cells. I was a bit confused at first. I think you are explaining the perivascular feet of Astrocytes. I am most-likely mistaken, but it is my understanding that oligiodendrocytes create the myelin on neurons in the CNS?
DeleteDaniel,
DeleteThat is correct. oligodendrocytes comprise the the blood brain barrier as well as the myelin of the CNS. because of their physical location they shuttle nutrients from the blood to the neurons. They also shuttle waste products from the neurons to the blood. I suspect that blood plasma may provide the existing glial cells that are supporting neurons with precursors that they have not received since their younger days.
Speculation as well.
ReplyDeleteHippocampal regeneration, specifically the regeneration of neurons from progenitor cells in the dentate gyrus, was demonstrated by using DNA markers (bromodeoxyuridine) in murine subjects over a decade ago (Eriksson, et. al., 1998). Dr. Campisi explains that the recent increased longevity in the human population illustrates that neurodegenerative diseases are more prevalent in the aging populations. It is clear that some chemical that is carried in the blood (hormonal) of "young" mice, that is absent or in low concentration in "aged" mice, might be responsible for the hippocampal fortification. Testosterone is a hormone whose concentration diminishes with age. Could "young" mice, who have a higher concentration of testosterone, be affording "aged" mice the needed boost to see noticeable changes in the hippocampal anatomy and cognitive improvements? If testosterone is this component in the plasma, then it raises the questions of how old are "young mice" and what concentration of testosterone must be maintained to create neurogeneration. What about female "young" mice donors and their effect on the data? Spritzer, M., et. al explains that testosterone does serve to enhance hippocampal regeneration (2007).
Eriksson, P., Perfilleva, E., Bjork-Eriksson, T., Alborn, A., Nordborg, C., Peterson, D., Gage, F. 1998. Neurogenesis in the Adult Human Hippocaampus. Nature Medicine [Internet]. 4(10):1313-1317. Avalible from: http://www.nature.com/nm/journal/v4/n11/full/nm1198_1313.html
Spritzer, M., Galea, L. 2007. Testosterone and Dihydrotestosterone, but not Estradiol, Enhance Survival of New Hippocampal Neurones in Adult Male Rates. Wiley Interscience [Interenet]. Avalible from: http://onlinelibrary.wiley.com/store/10.1002/dneu.20457/asset/20457_ftp.pdf;jsessionid=D1B6C57FC1DE2023B8EF3D8418B70FCD.f04t01?v=1&t=hzc9wrtt&s=dfb6e9f166ce01b97a0ce6d7315b44a9e7a8dc96
It is interesting to think that measures related to the creation of memories might one day be restored, however what are the other effects. Introduction of a foreign substance, even a substance our bodies may actually make, can cause a shift in homeostatic balance. It has been shown (http://www.ncbi.nlm.nih.gov/pubmed/25070042) that long-term use of a substance may cause certain glands to stop producing. Most of the time, secretion will resume once the foreign substance is removed from the body, but in this case, if the patient misses a dose will they not most certainly revert to an amnesia-like state since it is suggested that their bodies no long make the serum component to retain memories/information? Secondly, how much injected serum will it take to be therapeutic? Hematocrit is a prime example: a small increase has a huge physiological benefit, too much may lead to Ischemia or a MI. Even so, this study has huge potential and will be fascinating to follow.
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ReplyDeleteAustin, I think you make a solid point regarding metabolic factors. The plasma, while being comprised mostly of H20, has invaluable salts, enzymes, immunoglobulins, and carrier proteins. Perhaps, these components comprising the plasma help with hippocampal neurogenesis in patient's with neurodegenerative diseases. There was another study conducted (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3777974/) that supports Dr. Campisi's findings as well regarding the efficacy of plasma neurogensis in murine models affected by Alzheimer's disease (AD). The study effectively proved that plasma along with other plasma growth factors could help stimulate neurogenesis in the hippocampus thereby enhancing cognitive functioning in AD patient's. It also appears that plasma is a viable treatment option since this type of technology has already been successfully used in patient's suffering from life-threatening burns, trauma, and hemophilia with FDA approval. In addition, there are also numerous plasma donation centers across the country that make plasma readily available while efficiently screening donors so that high quality plasma can be administered to patients. This study is interesting to consider and will hopefully yield ground breaking treatments in the neurodegenerative disease arena.
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