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The cause of Alzheimer’s may be gum disease
This means the disease may be curable and a vaccine possible.
- Bacteria in periodontitis seems to be the culprit.
- Reported amyloid and tau buildups may be a response, not a cause.
- Compelling research offers a genuine reason for optimism.
Update, 1/31/2019: Science News has reported on the funding of this study, unpublished contradictory evidence, and the broad conclusions made in media headlines. Whenever new research claims a breakthrough, it's wise to reserve judgment just a bit, as we do. According to Rudolph Tanzi, Alzheimer's researcher at Massachusetts General Hospital in Boston, while it's true that gum disease may lead to Alzheimer's, it's far from proven. You can read his concerns here.
Dementia is now the fifth leading cause of death around the world, and 70 percent of that is due to Alzheimer's disease. Until now, experts have been baffled by what causes it, and powerless at slowing or reversing the cruel progress of this condition. Alzheimer's pulls its victims away from reality as their families watch, hearts breaking, until death delivers the final blow. That may be about to change, though, thanks to new research that suggests the cause of Alzheimer's is actually bacteria.
Porphyromonas gingivalis, to be specific — the inflamer of gum disease.
Has the role of protein deposits in patients’ brains been misunderstood?
Brain exhibiting plaque build-up, in blue. Image source: NIH Image Gallery
It's been known for a while that the brains of Alzheimer's victims have unusually high amounts of amyloid and tau proteins.This has led, naturally, to a suspicion that these proteins cause the disease. However, it turns out that some older people with exceptionally good memories have significant amounts of amyloid and tau proteins in their brains. This has called into question their causal role in the disease, and has led scientists to investigations of the possibility that the proteins may be appearing as a response to the actual culprit.
Gum disease in mice
P. gingivalis. Image source: NIH Image Gallery
Research from 2009 had identified a gum-disease bacteria, P. gingivalis IgG, as a frequent malady of Alzheimers suffers and frequently present in their brains. It was unclear, however, whether the patients' periodontitis had something to do with the disease or was simply a condition sufferers acquired after its onset.
A number of research teams conducted P. gingivalis experiments and found that its presence worsens Alzheimer's symptoms — including amyloid buildup — in mice bred to have the disease, and actually causes Alzheimer's in healthy mice.
An early clue
A few years back, Massachusetts General Hospital's Robert Moir started looking into the behaviors of a particular sequence of amino acids in beta amyloids. It exists in 70 percent of vertebrates, as well as some other animals, intriguing Moir, who told New Scientist, "This is a very old peptide doing something that's important." He found that the protein was a bacterial microbe killer. This suggested that the familiar buildups could be defending the brain against invading bacteria.
The smoking gun
(Dominy, et al)
The new study, which was published in Science Advances on January 23, reveals that toxic enzymes, gingipains, which allow P. gingivalis to feed on human flesh, were found in 96 percent of the tissue they examined from 54 Alzheimers' victims. Also, when they examined the DNA of three Alzheimer brains they found the P gingivalis in them all. Researcher Sim Singhrao of University of Central Lancashire, not involved in the study, tells New Scientist, "This is the first report showing P. gingivalis DNA in human brains, and the associated gingipains, co-lococalising with plaques."
As further confirmation, there was more of both the bacteria and its gingipains — and amyloid and tau buildup — in patients experiencing more advanced dementia.
The study also found that the gingipains mangle tau proteins so that they begin killing neurons. The result? Dementia.
What this means
Altogether, this may finally be the Alzheimer's breakthrough scientists have been waiting for.
- First off, the researchers discovered P. gingivalis in the spinal fluid of living patients, suggesting a means of early diagnosis since Alzheimer's may take from 10 to 20 years to develop before becoming symptomatic.
- Second, the bacteria may be vulnerable to treatment. Pharmaceutical firm Cortexyme is testing gingipain blockers that has resulted in improvement for Alzheimer's patients. Larger trials are imminent.
- Third, another team in Melbourne, Australia is working on a vaccine against gum disease and thus Alzheimer's.
The beginning of the end of Alzheimer’s?
We've gotten our hopes up before, but the new research provides genuine reason for optimism. The cause of this tragic condition may finally have been identified. As Cortexyme's Casey Lynch says, "We believe this is a universal hypothesis of pathogenesis."
Andy Samberg and Cristin Milioti get stuck in an infinite wedding time loop.
- Two wedding guests discover they're trapped in an infinite time loop, waking up in Palm Springs over and over and over.
- As the reality of their situation sets in, Nyles and Sarah decide to enjoy the repetitive awakenings.
- The film is perfectly timed for a world sheltering at home during a pandemic.
In more than a dozen countries as far apart as Portugal and Russia, 'Smith' is the most popular occupational surname
- 'Smith' is not just the most common surname in many English-speaking countries
- In local translations, it's also the most common occupational surname in a large part of Europe
- Ironically, Smiths are so ubiquitous today because smiths were so special a few centuries ago
Meet the Smiths, Millers, Priests and Imams - the most popular occupational surnames across Europe.
Image: Marcin Ciura<p>Although very few people are smiths by profession these days, there are millions of Smiths by surname the world over. It's the most popular surname in Britain, Australia, New Zealand and the United States, as well as the second most popular surname in Canada and the fifth most popular one in Ireland. And they're a thriving bunch, at least in the U.S.: the 2010 Census (1) counted 2,442,977 Americans called Smith, 2.8% more than in 2000.</p><p>Curiously, 'Smith' also is one of the most popular surnames across most of Europe –translated in the various local vernaculars, of course. This map shows the most common occupational surnames in each country. By colour-coding the professions, this map shows a remarkable pro-smith consistency across Europe – as well as some curious regional exceptions.</p>
‘Smith’ popular throughout Europe<p>'Smith', in all its variations, is the most popular occupational surname throughout Europe. Not just in the UK, but also in:</p> <ul><li>Belgium (<em>Desmet</em>) and Luxembourg, (<em>Schmitt</em>);</li> <li>France (<em>Lefebvre</em>), Italy (<em>Ferrari</em>) and Portugal (<em>Ferreira</em>);</li> <li>Slovenia (<em>Kovačič</em>), Croatia (<em>Kovačevič</em>), Hungary (<em>Kovács</em>), Slovakia (<em>Kováč</em>), Poland (<em>Kowalski</em>), Lithuania (<em>Kavaliauskas</em>), Latvia (<em>Kalējs</em>) and Belarus (<em>Kavalyov</em>);</li> <li>Estonia (<em>Sepp</em>); and</li> <li>Russia (<em>Kuznetsov</em>).</li></ul>
‘Miller’ on top in many Germanic-language countries<p>'Miller' is the most popular occupational surname in many Germanic-language countries, but also in Spain and Ukraine (perhaps because the grain in both countries is mainly in the plain):</p> <ul><li>There's <em>Müller</em> (in Germany and Switzerland), <em>M</em><em>ø</em><em>ller</em> (in Denmark and Norway) and <em>Möller</em> (Sweden);</li> <li><em>Molina</em> (in Spain – the map also shows the most popular surname in Catalonia/Catalan: <em>Ferrer</em>, i.e. 'Smith'); and</li> <li><em>Melnik</em> (in Ukraine).</li></ul>
Clergy surnames rule in the Balkans<p>Catholic clergy must remain celibate, so 'Priest' as a surname is rare to non-existent throughout Europe. Except in the Balkans, where Catholicism is largely absent. Here, the Orthodox and Islamic clergies have passed on the title from father to son, eventually as a surname, to popular effect. Orthodox clergy are addressed as <em>papa</em> or <em>pope</em> (which means 'father' – so the surname rather redundantly translates to 'father's son'). Islamic teachers or imams are known by the Turkish/Persian term <em>hodzha</em>. An overview:</p> <ul><li><em>Popov</em> (in Bulgaria), <em>Popovic</em> (in both Serbia and Montenegro), <em>Popovski</em> (in Macedonia);</li> <li><em>Popa</em> (in Romania); </li> <li><em>Papadopoulos</em> (in Greece); and</li> <li><em>Hodžić</em> (in Bosnia-Herzegovina), <em>Hoxha</em> (in both Kosovo and Albania).</li></ul>
Landowners and other professions<p>Austria and the Czech Republic have different national languages but are neighbours and share a lot of history. Could that explain why they have a similar most popular occupational surname, for 'landowner'?</p> <ul><li><em>Huber</em> (in Austria) and</li> <li><em>Dvořák</em> (in the Czech Republic).</li></ul> <p>Just four professions, that wraps up all but five countries on this map. Those five each have their very own most popular occupational surname:</p> <ul><li><em>Bakker</em> (in the Netherlands): 'Baker'</li> <li><em>Kinnunen</em> (in Finland): 'Skinner'</li> <li><em>Ceban</em> (in Moldova): 'Shepherd'</li> <li><em>Avci</em> (in Turkey): 'Hunter'</li> <li><em>Murphy</em> (in Ireland): 'Sea Warrior' </li></ul>
Even more Smiths<p>Judging from the popularity of these surnames, your generic European village of a few centuries ago really couldn't do without a smithy. It was a much more essential craft even than that of the miller (or the baker, who put the miller's flour to good use) – except in the Balkans, where spiritual sustenance apparently sated a greater need. On the outskirts of <em>Anytown, Europe</em> live the shepherd and the hunter, the skinner and the pirate.<br></p><p>A bit too simplistic? Perhaps not simplistic enough. This map could have been dominated by even more Smiths. As the original poster explains, he always picked the most frequent version of an occupational surname, even if multiple variants point to a more popular alternative. </p><p>In the Netherlands, for instance, people with the surnames <em>Smit, Smits, Smid, de Smit, Smet </em>and <em>Smith</em> collectively outnumber those with the surnames <em>Bakker, Bekker, de Bakker</em> and <em>Backer</em>. So, the Netherlands could be considered another win for 'Smith' – except that the variant <em>Bakker</em> is more frequent than any other single variant.</p><p>Same story in Germany: added up, there are more people named <em>Schmidt, Schmitt, Schmitz </em>and <em>Schmid</em> than <em>Müller</em>. Ditto for Spain: <em>Herrero, Herrera </em>and <em>Ferrer</em> together outnumber <em>Molina</em>. Also in Finland, where <em>Seppä</em>, <em>Seppälä</em> and <em>Seppänen</em> together have a higher count than <em>Kinnunen</em>. </p>
Smiths in other cultures<p>'Smith' was a crucial occupation in other cultures too, judging from the familiar ring it has in these languages:<br></p><ul><li><em></em><em>Demirci</em> (Turkish)</li><li><em>Hadad</em> (Syriac, Aramaic, Arabic)</li><li><em>Nalbani</em> (Albanian)</li><li><em>McGowan</em> (Gaelic)</li><li><em>Faber</em> (Latin)<span></span></li></ul>
Other most popular surnames<p>Take note, though: 'Smith' may be the most popular surname in in the Anglosphere, this map does not mean to show that its variants in French, Russian and other languages also are the most popular surnames in the countries marked grey. They are merely the most popular <em>occupational</em> surnames.<br></p><p>As this sample of most common ones for each country shows, surnames can refer to a host of other things. Personal qualities or physical attributes, for example:</p> <ul><li>Russia: <em>Smirnov</em> ('the quiet one')</li> <li>Turkey: <em>Yilmaz</em> ('unflinching')</li> <li>Hungary: <em>Nagy</em> ('big')</li> <li>Italy: <em>Rossi/Russo</em> ('red', in northern and southern Italy, respectively)</li></ul> <p>Another option: the origin of the name-bearer (be it a place or a person):</p> <ul><li>Sweden: <em>Andersson</em> ('son of Anders')</li> <li>Slovakia: <em>Horvath</em> ('Croat')</li> <li>Kosovo: <em>Krasniqi</em> (refers to the Krasniq tribe and their mountainous home region)</li> <li>Portugal: <em>Silva</em> ('woodland')</li> <li>Latvia: <em>Bērziņš</em> ('little birch tree')</li> <li>Estonia: <em>Tamm</em> ('oak')</li></ul> <p>But sometimes, even for the most popular ones, the exact origin of the surname is lost in time:</p> <ul><li>Spain: <em>Garcia</em> (originally Basque, possibly meaning 'young', 'bear' or 'young bear')</li> <li>Finland: <em>Korhonen</em> ('hard of hearing' or 'dim-witted'; 'village elder'; 'proud'; 'upright'). </li></ul>
Smith popularity theory<p>So why exactly is Smith – and not Miller, for example – the most popular surname in many English-speaking countries? The theory propounded by historian C.M. Matthews in <em>History Today</em> (July 1967) probably also holds for the other-language variants so popular throughout Europe:<br></p><blockquote>"The reason for (the) multiplicity (of the surname 'Smith') is not so much that metal-workers were numerous as that they were important and widespread. On the skill of the smith, both rich and poor depended for the most essential things of life, the tools of husbandry and the weapons of hunting and war. Every community in the land must have one, every castle, every manor; and so distinctive was his trade that he would seldom need another name".<em></em></blockquote><p>That does not mean all people with the surname have a forefather who forged iron into weapons and farm tools. Especially in North America, 'Smith' was adopted by many people precisely because it was already common – as a secret identity or to blend in, for example by natives, slaves and immigrants.</p>
A recent analysis of a 76-million-year-old Centrosaurus apertus fibula confirmed that dinosaurs suffered from cancer, too.
- The fibula was originally discovered in 1989, though at the time scientists believed the damaged bone had been fractured.
- After reanalyzing the bone, and comparing it with fibulas from a human and another dinosaur, a team of scientists confirmed that the dinosaur suffered from the bone cancer osteosarcoma.
- The study shows how modern techniques can help scientists learn about the ancient origins of diseases.
Centrosaurus apertus fibula
Royal Ontario Museum<p>In the recent study, the team used a combination of techniques to analyze the fibula, including taking CT scans, casting the bone and studying thin slices of it under a microscope. The analysis suggested that the dinosaur likely suffered from osteosarcoma, a type of bone cancer that affects modern humans, typically young adults.</p><p>For further evidence, the team compared the damaged fibula to a healthy fibula from a dinosaur of the same species, and also to a fibula that belonged to a 19-year-old human who suffered from osteosarcoma. Both comparisons supported the osteosarcoma diagnosis.</p>
Evans et al.<p style="margin-left: 20px;">"The shin bone shows aggressive cancer at an advanced stage," Evans said in a <a href="https://www.rom.on.ca/en/about-us/newsroom/press-releases/rare-malignant-cancer-diagnosed-in-a-dinosaur" target="_blank">press release</a>. "The cancer would have had crippling effects on the individual and made it very vulnerable to the formidable tyrannosaur predators of the time."</p><p style="margin-left: 20px;">"The fact that this plant-eating dinosaur lived in a large, protective herd may have allowed it to survive longer than it normally would have with such a devastating disease."</p><p>The fossilized fibula was originally unearthed in a bonebed alongside the remains of dozens of other <em>Centrosaurus </em><em>apertus</em>, suggesting the dinosaur didn't die from cancer, but from a flood that swept it away with its herd.</p>
Dinosaur fibula; the tumor mass is depicted in yellow.
Royal Ontario Museum/McMaster University<p>The new study highlights how modern techniques can help scientists learn more about the evolutionary origins of modern diseases, like cancer. It also shows that dinosaurs suffered through some of the same terrestrial afflictions humans face today.</p><p style="margin-left: 20px;">"Dinosaurs can seem like mythical creatures, but they were living, breathing animals that suffered through horrible injuries and diseases," Evans said, "and this discovery certainly makes them more real and helps bring them to life in that respect."</p>
Join the lauded author of Range in conversation with best-selling author and poker pro Maria Konnikova!
UPDATE: Unfortunately, Malcolm Gladwell was not able to make the live stream due to scheduling issues. Fortunately, David Epstein was able to jump in at a moment's notice. We hope you enjoy this great yet unexpected episode of Big Think Live. Our thanks to David and Maria for helping us deliver a show, it is much appreciated.