Ludo wanted to let us know he loves his new home Ludo (formerly Fizziwig) has been in his forever home for over 6 months. 
Toby (Gabriel) was adopted w Ludo. Look at how precious they are.  Twins. 
Callie (aka Olivia, my foster mini Australian puppy) lives there too.  We love this family.  
They have kid siblings and also other dog friends.  Their home is a happy place. 

I’m so glad the boys were adopted together! ❤️❤️

Her sister, Scout, wears glasses during her laser treatment. 

Let’s talk about this paper, which has made quite a splash. The authors present data for the hypothesis that one of the causes of Alzheimer’s disease is lithium deficiency, and I have to say, I had not run across that one before. But I am alway ready to hear about new approaches in Alzheimer’s, which really, really needs some and has for many years now. So how well does this idea hold up? The next couple of paragraphs are some analytical chemistry background, then we'll get into the biology.

The work starts off by using ICP-MS (inductively coupled plasma mass spectroscopy) to measure the levels of 27 different metallic elements in the brain, and that’s fine. ICP-MS is just what people use for trace metals analysis. The business end of this instrument is a set of quartz tubes where argon gas is pass through a powerful induction coil that operated at a ridiculously high frequency (millions of cycles per second). An electric spark starts things off by adding some free electrons into this gas stream, and the magnetic field of the induction coil sends this violently whipping back and forth at that high frequency. As these whack into more argon atoms, more electrons can be released from them, and these now join the induction party, releasing still more electrons from the argon atoms, and so on. You take that up to the point where the rate of electron production is balanced out by the rate of recombination (argon atoms picking up free electrons and getting back to neutral), and that plasma state occurs at around 10,000 degrees.

As you’d imagine, molecules in the sample get ripped to pieces under such conditions, and the resulting atoms get ionized in turn, even though they’re typically flowing through a slightly cooler zone in the middle of the plasma flame. You can adjust the plasma temperature for the best signal/noise, which generally means tuning things for the first (single-charged) ions with less of the multiply-charged ones for the element of interest. Most everything is easier to ionize than argon! The flow takes these ions into the mass spec portion of the instrument, and calibrating with reference standards lets you read off the concentrations of each ion. You need to be mindful of the possibility of contamination of your sample, because ICP-MS ionizes and spares not, but the work flows for this stuff are well established, and this is the instrumentation used for suspected cases of heavy metal poisoning and the like.

In this work, the authors compare brain tissue samples from people with no signs of Alzheimer’s to those with a definite diagnosis of mild cognitive impairment (MCI) and to samples from full-blown Alzheimer’s disease (AD) patients. Inside these they compare samples from the prefrontal cortex (PFC) region, which is heavily affected in the disease, to samples from back in the cerebellum, which is not. In all of these cases they also look at metal levels on a tissue-to-serum ratio basis, checking for discrepancies.

And lithium appears to be the only metal that really jumps out as having strange concentrations. This will come as a surprise to those of us who are old enough to remember the aluminum-causes-Alzheimer’s headlines from decades past, but given the awful solubility of aluminum species under physiological conditions that story had an uphill climb to plausibility anyway. But no one has ever complained about the solubility of lithium ions. It also helps put to rest some other metal-toxicity theories that have cropped up over the years, many of which were kept going due to large-error-bar measurement techniques. It’s worth noting that several metals do have changes in tissue/serum ratios in Alzheimer’s tissues as compared to nonimpaired controls (lead, copper, arsenic, vanadium and zinc in particular), but of these only lithium shows up as a statistical oddity in the mildly impaired group as well (and it is way off in the AD samples). You can find these numbers in the paper’s Supplementary Information, Table 1.

Li appears to be significantly reduced in the PFC samples of both the MCI and AD cohorts. Zooming in closer on a histopathological level, doing the ICP-MS analysis with a laser absorption sampling front end (where you aim small energetic laser spots at different regions of a sample) shows that the lithium seems to be piling up in the Alzheimer’s plaques themselves, an effect that gets stronger as you go from the mild-impairment samples to the full AD ones. That ties in with a great deal of literature suggesting metal ion sequestration in the plaques (which is where some of the previous metal theories had their start). So the lower lithium levels are especially noticeable in the non-plaque tissue workup, which is after all the more soluble fraction (and explains why the initial readouts were indeed for low Li levels). What’s more, low lithium levels in the non-plaque tissue seem to correlate significantly with cognitive function scores of the patients themselves, particularly episodic memory (Supplementary Information, Table 2).

Putting mice on a deliberate low-lithium diet caused some very interesting problems in the brain tissue. Animals bred with mutations that make them susceptible to amyloid or tau deposition show notably increased amounts of both on low-Li diets, and even wild-type mice show increased levels of beta-amyloid 1-42. Both the mutant lines and wild-type mice showed significant memory deficits in cognitive tests (such as the good ol’ Morris water maze) on the low-Li diets as compared to normally fed counterparts. The paper has an extended discussion of the transcriptional effects that ensue as well, and this particularly implicates elevation of the levels of the kinase GSK3-beta under Li deficiency. That one will be quite familiar to Alzheimer’s research aficionados, as it has been implicated by several other lines of evidence.

An intriguing part of the paper concerns lithium supplementation (as opposed to deliberate lithium deficiencies). The team settled on lithium orotate after measuring the conductivities of a whole list of lithium salts and finding that this one seemed to be the least-ionized of the lot and bound the least to AD plaques in vitro. Indeed, a head-to-head comparison of lithium supplementation in the drinking water of the mutant mice mentioned above showed that when they were given lithium carbonate (the Li salt form used to treat some types of depression) versus lithium orotate that the lithium in the lithium carbonate ended up sequestered in plaques to a much greater degree despite very similar Li plasma concentration for each. Corresponding Li levels in the non-plaque tissue were more elevated in the Li orotate group.

And here’s a real kicker: such lithium orotate supplementation in the 3xTg mutant mice almost completely prevented amyloid plaque formation and accumulation of phosphorylated tau in their brains, whereas supplementation with lithium carbonate (or sodium orotate) had no real effects. A similar effect of lower plaque burdens could be seen in both mutant lines even when started in mice at an age where plaques were already forming. Transcription analysis of these mice showed a whole range of changes in genes known to be associated with memory and neuronal function. And what’s more, these results carried over to wild-type mice: the memory deficits associated with normal aging in these mice were “largely reversed” under lithium orotate supplementation. These effects extend down to the level of analysis of neurons, microglia, and oligodendrocytes at a histopathological and transcriptional level.

I will confess that I did not expect to be as impressed by this paper as I ended up being. There’s a lot of hand-waving in the Alzheimer’s disease hypothesis field, but there seems to be a lot of solid research in here.  This is some of the most interesting work I’ve read in the area for a long time, and I hope it stimulates a lot of effort replicating and extending its findings. The connections (and differences) between lithium deficiency and supplementation are a particular highlight, and as a 63 year old, I would very much like to see some toxicology work commence on lithium orotate as quickly as possible!

Dickens was helping me in the guest room.   Maybe he was afraid it was chaos downstairs.  
Granger said, "I'm not chaos!"  That's true.   He just sweet.  Naps are his thing.
Toasty is still recovering from his back injury.  I am continuing his red-light therapy.  Dickens still gets it too.   Toasty would love to be chaotic, but we limit him.  He needs to heal.
Tuk Tuk would love chaos-- he can't play with Toasty right now-- not allowed- but he's tried to get Cinnamon involved.  She was not amused.  LOLTuk Tuk checked out the lounger in our room but then got on the bed beside me.  
There he is with Granger on the middle part too.  My tall husband's area is definitely being affected. After Granger tried to fit in the flowerpot, I found a box in the attic.  He went right into it.  
Gomez' mom made his box fancy!  He even has a "Peke look out." 🤣Tuk Tuk had to try it out-- and he began chewing on some of it.  Toasty is getting sleepy.   I think it's time for a rest.   I might join him.  They're all spread out around the porch.    Nap breaks are great!! 😴💤
 

Magoo came into rescue almost five years ago.  He was part of the Potomac Six from NC. Since he was adopted, he has traveled so much!  Italy, Germany— and now he has moved to Hawaii!  He visited some friends on the way there. It takes a long time to get your furniture all the way from Italy.  Magoo has a lot of empty space to play in. 

Here’s yet another one of those “Man, biology just will not stop piling on the multitasking” examples. Everyone has heard of serotonin as a signaling molecule and neurotransmitter - it’s one of the few that has name recognition even among people who don’t work in biomedicine at all.  But its effects in vivo are extremely varied and complex, not least because there are 13 subtypes of serotonin receptor stretched across six different families, with these occurring in a bewildering variety of different tissues (cardiovascular, the immune system, and many more). It’s a perfect example of evolution stumbling on a useful tool and then picking it up over and over again.

This new paper proposes, for example, that the serotonin reuptake inhibitors (SSRIs), which are famous as antidepressants among other uses, could have a role in cancer therapy. The reuptake pathway seems to inhibit CD8 T-cell antitumor immunity by keeping serotonin levels inside tumor tissue low (there’s that immune system connection just mentioned). And the paper shows that administration of SSRIs like fluoxetine (famous under the brand name Prozac) or citalopram (widely known as Celexa) at normal therapeutic doses in mouse cancer models significantly reduced tumor growth and improved survival across a range of different types (melanoma, colon, bladder, breast). Closer examination indicated that more active CD8 T cells appear to have been behind these effects. You might expect such a mode of action to synergize with anti-PD-1 immunooncology therapy, and so it proved: giving the SSRI drugs along with antibodies against mouse-type PD-1 showed even greater effects than either treatment alone. 

This would seem to be immediately actionable in clinical trials. One thing to keep in mind, though, is that the number of cancer patients who are already getting SSRIs is not insignificant, so that is going to have to be untangled along the way. Perhaps some of the benefit of that (and other) cancer treatments that we’ve seen have been unexpectedly helped along a bit because we didn’t take this effect into account. And there are of course a lot of other potential mechanisms at work here, given the complexity of serotonin signaling in general. But it should be relatively straightforward to see if adding an SSRI to the treatment regimen patients getting anti-PD-1 cancer therapy improves their outcomes. And if it does, so much the better! These drugs are cheap and widely available.

There are plenty of other immune-modulating pathways that we’re just beginning to get a handle on (or are just beginning to realize that they exist at all). And that’s why I roll my eyes when I hear anyone say that they wonder if immuno-oncology is somehow “played out”. No, we’ve just been messing around with the stuff that we know the most about and running variations on those. It’s going to be a long, long time before we’ve exhausted the possibilities. If you’re looking for a boost to your company’s stock price by the second quarter of next year, then yeah, that’s tougher. But in the long term of the real world out here, there is just so, so much to do.