Aging and its 11 hippocampal genes

Aging is being quite extensively studied these days and here is another advance in the field. Pardo et al. (2017) looked at what happens in the hippocampus of 2-months old (young) and 28-months old (old) female rats. Hippocampus is a seahorse shaped structure no more than 7 cm in length and 4 g in weight situated at the level of your temples, deep in the brain, and absolutely necessary for memory.

First the researchers tested the rats in a classical maze test (Barnes maze) designed to assess their spatial memory performance. Not surprisingly, the old performed worse than the young.

Then, they dissected the hippocampi and looked at neurogenesis and they saw that the young rats had more newborn neurons than the old. Also, the old rats had more reactive microglia, a sign of inflammation. Microglia are small cells in the brain that are not neurons but serve very important functions.

After that, the researchers looked at the hippocampal transcriptome, meaning they looked at what proteins are being expressed there (I know, transcription is not translation, but the general assumption of transcriptome studies is that the amount of protein X corresponds to the amount of the RNA X). They found 210 genes that were differentially expressed in the old, 81 were upregulated and 129 were downregulated. Most of these genes are to be found in human too, 170 to be exact.

But after looking at male versus female data, at human and mouse aging data, the authors came up with 11 genes that are de-regulated (7 up- and 4 down-) in the aging hippocampus, regardless of species or gender. These genes are involved in the immune response to inflammation. More detailed, immune system activates microglia, which stays activated and this “prolonged microglial activation leads to the release of pro-inflammatory cytokines that exacerbate neuroinflammation, contributing to neuronal loss and impairment of cognitive function” (p. 17). Moreover, these 11 genes have been associated with neurodegenerative diseases and brain cancers.


These are the 11 genes: C3 (up), Cd74  (up), Cd4 (up), Gpr183 (up), Clec7a (up), Gpr34 (down), Gapt (down), Itgam (down), Itgb2 (up), Tyrobp (up), Pld4 (down).”Up” and “down” indicate the direction of deregulation: upregulation or downregulation.

I wish the above sentence was as explicitly stated in the paper as I wrote it so I don’t have to comb through their supplemental Excel files to figure it out. Other than that, good paper, good work. Gets us closer to unraveling and maybe undoing some of the burdens of aging, because, as the actress Bette Davis said, “growing old isn’t for the sissies”.

Reference: Pardo J, Abba MC, Lacunza E, Francelle L, Morel GR, Outeiro TF, Goya RG. (13 Jan 2017, Epub ahead of print). Identification of a conserved gene signature associated with an exacerbated inflammatory environment in the hippocampus of aging rats. Hippocampus, doi: 10.1002/hipo.22703. ARTICLE

By Neuronicus, 25 January 2017




100% Effective Vaccine

A few days ago I was reading random stuff on the internet, as is one’s procrastination proclivity, catching up after the holiday, and I exclaimed out loud: “They discovered an 100% effective Ebola Vaccine!”. I expected some ‘yeay’-s or at least some grunts along the lines of ‘that’s nice’ or ‘cool’. Naturally, I turned around from my computer to check the source of unaccustomed silence to the announcement of such good news or, at least, to make sure that everybody is still breathing and present in the room. What met my worried glare was a gloom face and a shaking head. That’s because news like that are misleading, because, duh, it finally dawned on me, there is no such thing as ‘100% effective vaccine’.

And yet…, and yet this is exactly what Henao-Restrepo et al. (2016) say they found! The study is huge, employing more that 10 000 people. Such a tremendous endeavor has been financed by WHO (World Health Organization) and various departments from several countries (UK, USA, Switzerland, South Africa, Belgium, Germany, France, Guinea, and Norway) and, I’m assuming, a lot of paid and unpaid volunteers. I cannot even imagine the amount of work and the number of people that made this happen. And the coordination required for such speedy results!

The successful vaccine in rodents and non-human primates, called the recombinant, replication-competent, vesicular stomatitis virus-based vaccine expressing the glycoprotein of a Zaire Ebolavirus (rVSV-ZEBOV) has been taken to the Republic of Guinea and rapidly administered to volunteers who were in contact with somebody that had Ebola symptoms. And their contacts. I mean the contacts and the contacts of contacts of the Ebola patient. Who were contacted by the researchers within 2 days of a new Ebola case based on the patient’s list of contacts. And of contacts of contacts. Is not that complicated, honest.

After vaccinations, the “vaccinees were observed for 30 min post-vaccination and at home visits on days 3, 14, 21, 42, 63, and 84” (p.4). Some volunteers received the vaccine immediately, others after 3 weeks. No one who received the vaccine immediately developed Ebola, which lead the researchers to claim that the vaccine is 100% effective. Only 9 from the delayed vaccination group developed Ebola within 10 days of vaccination, but the researchers figured that these people probably contacted Ebola prior to the vaccination, since the disease requires typically about 10 days to show its ugly  horns.

So this is great news. Absolutely great. Even if, as always, I could nitpick thorough the paper, squabble over the “typically” 10-day incubation period, and cock an eyebrow at the new-fangled ring vaccination design as opposed to the old-fashioned placebo approach. Even after these minor criticisms this is – I repeat – GREAT NEWS!

P.S. Don’t ever say that the UN didn’t do anything for you.


Reference: Henao-Restrepo AM, Camacho A, Longini IM, Watson CH, Edmunds WJ, Egger M, Carroll MW, Dean NE, Diatta I, Doumbia M, Draguez B, Duraffour S, Enwere G, Grais R, Gunther S, Gsell PS, Hossmann S, Watle SV, Kondé MK, Kéïta S, Kone S, Kuisma E, Levine MM, Mandal S, Mauget T, Norheim G, Riveros X, Soumah A, Trelle S, Vicari AS, Røttingen JA, Kieny MP. (22 Dec 2016). Efficacy and effectiveness of an rVSV-vectored vaccine in preventing Ebola virus disease: final results from the Guinea ring vaccination, open-label, cluster-randomised trial (Ebola Ça Suffit!). Lancet. pii: S0140-6736(16)32621-6. doi: 10.1016/S0140-6736(16)32621-6. PMID: 28017403 [Epub ahead of print] ARTICLE | FREE FULLTEXT PDF | Good Nitpicking in The Conversation

By Neuronicus, 18 January 2017