(Waking Times | Karen Foster) Researchers have long suggested a link between the gut-brain axis and neuropsychiatric disorders such as autism, depression, and eating disorders. Using probiotics and prebiotics to alter the gut microbiota and influence the gut-brain axis may open up new ways of influencing neuropsychological conditions, says a new review.
The majority of the science for probiotics has focused on gut health, but as the understanding of the gut and the microbiome increases, probiotics are increasing linked to a range of beneficial effects, from weight management to immune support and allergy response, and from oral health to cholesterol reduction.
The gut contains microorganisms that share a structural similarity with the neuropeptides involved in regulating behavior, mood, and emotion – a phenomenon known as molecular mimicry.
At the “forefront of current research” is work on the gut-brain axis – the two direction communication between the gut microbiota and the brain. Data from rodent studies has indicated that modification of the gut microbiota can alter signaling mechanisms, emotional behavior, and instinctive reflexes.
Researchers have long postulated that gut bacteria influence brain function. A century ago, Russian embryologist Elie Metchnikoff surmised that a healthy colonic microbial community could help combat senility and that the friendly bacterial strains found in sour milk and yogurt would increase a person’s longevity.
According to a new review in Neuropsychiatric Disease and Treatment by Linghong Zhou and Jane Foster from McMaster University in Canada, communication channels between the gut and the brain include sympathetic and parasympathetic nerves and the enteric nervous system (ENS).
“The role of the sympathetic nervous system in the gut-brain axis includes regulating motility, blood flow, barrier function, and immune system activation”, they said. “Bidirectional communication via the vagus nerve, a component of the parasympathetic nervous system, is a well-established pathway for gut-brain signaling and, in recent years, has emerged as an important microbiota to brain communication pathway.“The ENS, sometimes referred to as “the second brain” comprises intrinsic primary afferent neurons, motor neurons, and glial cells contained within the myenteric plexus and the submucosal plexus that extends along the entire length of the gut. The ENS plays an essential role in normal intestinal function including motility and secretion.”
The body can’t tell the difference between the structure of these mimics and its own cells, so antibodies could end up attacking both, potentially altering the physiology of the gut-brain axis. The bacteria present in the gut affects the communication between belly and brain, they said, and the lack of healthy gut microbiota lead to dysfunction in the gut-brain axis, which in turn may lead to neuropsychological, metabolic, and gastrointestinal disorders.
Intervention trials with select strains of probiotics have revealed that supplementation may influence mood (Lactobacillus casei Shirota), and anxiety and depression (L. helveticus and B. longum). There is also some data to support an effect with prebiotics, with improvements in stress hormone levels and attention in health volunteers taking oligosaccharides.
The role of the gut microbiota in the development of neuropsychological disorders is also a focus for many researchers around the world, with data supporting an association between dysbiosis (microbial imbalance) in the gut and disorders including depression and autism spectrum disorder, metabolic disorders such as obesity, and gastrointestinal disorders including IBD and IBS.
“Fortunately, studies have also indicated that gut microbiota may be modulated with the use of probiotics, antibiotics, and fecal microbiota transplants as a prospect for therapy in microbiota-associated diseases”, wrote Zhou and Foster. “This modulation of gut microbiota is currently a growing area of research as it just might hold the key to treatment.”
The power of probiotics
Probiotics offset other intestinal bacteria that produce putrefactive and carcinogenic toxins. If harmful bacteria dominate the intestines, essential vitamins and enzymes are not produced and the level of harmful substances rises leading to cancer, liver and kidney disease, hypertension, arteriosclerosis and abnormal immunity. Harmful bacteria can proliferate under many different circumstances including peristalsis disorders, surgical operations of the stomach or small intestine, liver or kidney diseases, pernicious anaemia, cancer, radiation or antibiotic therapies, chemotherapy, immune disorders, emotional stress, poor diets and aging
The best known of the probiotics are the Lactobacilli, a number of species of which (acidophilus, bulgaricus, casei and sporogenes) reside in the human intestine in a symbiotic relationship with each other and with other microorganisms (the friendly Streptococci, E. coli and Bifidobacteria). Lactobacilli are essential for maintaining gut microfloral health, but the overall balance of the various microorganisms in the gut is what is most important.
Another probiotic which has recently generated a great deal of interest is the friendly yeast known as Saccharomyces boulardii, an organism that belongs to the Brewer’s Yeast family, not the Candida albicans group. S. boulardii is not a permanent resident of the intestine but, taken orally, it produces lactic acid and some B vitamins, and has an overall immune enhancing effect. In fact, it has been used therapeutically to fight candida infections.
Six surprising facts about microbes in your gut 1. What’s in your gut may affect the size of your gut
Need to lose weight? Why not try a gut bacteria transplant?New research published in the journal Sciencesuggests that the microbes in your gut may play a role in obesity.
2. Probiotics may treat anxiety and depression
Scientists have been exploring the connection between gut bacteria and chemicals in the brain for years. New research adds more weight to the theory that researchers call “the microbiome–gut–brain axis.”Research published in Proceedings of the National Academy of Science shows that mice fed the bacterium Lactobacillus rhamnosus showed fewer symptoms of anxiety and depression. Researchers theorize that this is because L. rhamnosus acts on the central gamma-aminobutyric acid (GABA) system, which helps regulate emotional behavior. L. rhamnosus, which is available as a commercial probiotic supplement, has also been linked to the prevention of diarrhea, atopic dermatitis, and respiratory tract infections.
3. The more bacteria the better
While bacteria on the outside of your body can cause serious infections, the bacteria inside your body can protect against it. Studies have shown that animals without gut bacteria are more susceptible to serious infections.Bacteria found naturally inside your gut have a protective barrier effect against other living organisms that enter your body. They help the body prevent harmful bacteria from rapidly growing in your stomach, which could spell disaster for your bowels. To do this, they develop a give-and-take relationship with your body. “The host actively provides a nutrient that the bacterium needs, and the bacterium actively indicates how much it needs to the host,” according to research published in The Lancet.
4. Gut bacteria pass from mother to child in breast milk
It’s common knowledge that a mother’s milk can help beef up a baby’s immune system. New research indicates that the protective effects of gut bacteria can be transferred from mother to baby during breastfeeding. Work published in Environmental Microbiology shows that important gut bacteria travels from mother to child through breast milk to colonize a child’s own gut, helping his or her immune system to mature.
5. Lack of gut diversity is linked to allergies
Too few bacteria in the gut can throw the immune system off balance and make it go haywire with hay fever.
Researchers in Copenhagen reviewed the medical records and stool samples of 411 infants. They found that those who didn’t have diverse colonies of gut bacteria were more likely to develop allergies. But before you throw your gut bacteria a proliferation party, know that they aren’t always beneficial.
6. Gut bacteria can hurt your liver
Your liver gets 70 percent of its blood flow from your intestines, so it’s natural they would share more than just oxygenated blood. Italian researchers found that between 20 and 75 percent of patients with chronic fatty liver disease–the kind not associated with alcoholism–also had an overgrowth of gut bacteria. Some believe that the transfer of gut bacteria to the liver could be responsible for chronic liver disease.
Denkfouten zorgen ervoor dat de landbouw en veehouderij een moeizame toekomst tegemoet gaan. Het roer moet om, vindt Jan Feersma Hoekstra van Agriton. Het kortetermijndenken, met de nadruk op een zo hoog mogelijke productie, heeft geen toekomst.
De aandacht moet gaan naar een goede gezondheid van bodem en vee. Microbiologie lijkt hierbij het toverwoord.
The rich array of microbiota in our intestines can tell us more than you might think.
Eighteen vials were rocking back and forth on a squeaky mechanical device the shape of a butcher scale, and Mark Lyte was beside himself with excitement. ‘‘We actually got some fresh yesterday — freshly frozen,’’ Lyte said to a lab technician. Each vial contained a tiny nugget of monkey feces that were collected at the Harlow primate lab near Madison, Wis., the day before and shipped to Lyte’s lab on the Texas Tech University Health Sciences Center campus in Abilene, Tex.
Lyte’s interest was not in the feces per se but in the hidden form of life they harbor. The digestive tube of a monkey, like that of all vertebrates, contains vast quantities of what biologists call gut microbiota. The genetic material of these trillions of microbes, as well as others living elsewhere in and on the body, is collectively known as the microbiome. Taken together, these bacteria can weigh as much as six pounds, and they make up a sort of organ whose functions have only begun to reveal themselves to science. Lyte has spent his career trying to prove that gut microbes communicate with the nervous system using some of the same neurochemicals that relay messages in the brain.
Inside a closet-size room at his lab that afternoon, Lyte hunched over to inspect the vials, whose samples had been spun down in a centrifuge to a radiant, golden broth. Lyte, 60, spoke fast and emphatically. ‘‘You wouldn’t believe what we’re extracting out of poop,’’ he told me. ‘‘We found that the guys here in the gut make neurochemicals. We didn’t know that. Now, if they make this stuff here, does it have an influence there? Guess what? We make the same stuff. Maybe all this communication has an influence on our behavior.’’
Since 2007, when scientists announced plans for a Human Microbiome Project to catalog the micro-organisms living in our body, the profound appreciation for the influence of such organisms has grown rapidly with each passing year. Bacteria in the gut produce vitamins and break down our food; their presence or absence has been linked to obesity, inflammatory bowel disease and the toxic side effects of prescription drugs. Biologists now believe that much of what makes us human depends on microbial activity. The two million unique bacterial genes found in each human microbiome can make the 23,000 genes in our cells seem paltry, almost negligible, by comparison. ‘‘It has enormous implications for the sense of self,’’ Tom Insel, the director of the National Institute of Mental Health, told me. ‘‘We are, at least from the standpoint of DNA, more microbial than human. That’s a phenomenal insight and one that we have to take seriously when we think about human development.’’
Given the extent to which bacteria are now understood to influence human physiology, it is hardly surprising that scientists have turned their attention to how bacteria might affect the brain. Micro-organisms in our gut secrete a profound number of chemicals, and researchers like Lyte have found that among those chemicals are the same substances used by our neurons to communicate and regulate mood, like dopamine, serotonin and gamma-aminobutyric acid (GABA). These, in turn, appear to play a function in intestinal disorders, which coincide with high levels of major depression and anxiety. Last year, for example, a group in Norway examined feces from 55 people and found certain bacteria were more likely to be associated with depressive patients.
At the time of my visit to Lyte’s lab, he was nearly six months into an experiment that he hoped would better establish how certain gut microbes influenced the brain, functioning, in effect, as psychiatric drugs. He was currently compiling a list of the psychoactive compounds found in the feces of infant monkeys. Once that was established, he planned to transfer the microbes found in one newborn monkey’s feces into another’s intestine, so that the recipient would end up with a completely new set of microbes — and, if all went as predicted, change their neurodevelopment. The experiment reflected an intriguing hypothesis. Anxiety, depression and several pediatric disorders, including autism and hyperactivity, have been linked with gastrointestinal abnormalities. Microbial transplants were not invasive brain surgery, and that was the point: Changing a patient’s bacteria might be difficult but it still seemed more straightforward than altering his genes.
When Lyte began his work on the link between microbes and the brain three decades ago, it was dismissed as a curiosity. By contrast, last September, the National Institute of Mental Health awarded four grants worth up to $1 million each to spur new research on the gut microbiome’s role in mental disorders, affirming the legitimacy of a field that had long struggled to attract serious scientific credibility. Lyte and one of his longtime colleagues, Christopher Coe, at the Harlow primate lab, received one of the four. ‘‘What Mark proposed going back almost 25 years now has come to fruition,’’ Coe told me. ‘‘Now what we’re struggling to do is to figure out the logic of it.’’ It seems plausible, if not yet proved, that we might one day use microbes to diagnose neurodevelopmental disorders, treat mental illnesses and perhaps even fix them in the brain.
In 2011, a team of researchers at University College Cork, in Ireland, and McMaster University, in Ontario, published a study in Proceedings of the National Academy of Science that has become one of the best-known experiments linking bacteria in the gut to the brain. Laboratory mice were dropped into tall, cylindrical columns of water in what is known as a forced-swim test, which measures over six minutes how long the mice swim before they realize that they can neither touch the bottom nor climb out, and instead collapse into a forlorn float. Researchers use the amount of time a mouse floats as a way to measure what they call ‘‘behavioral despair.’’ (Antidepressant drugs, like Zoloft and Prozac, were initially tested using this forced-swim test.)
For several weeks, the team, led by John Cryan, the neuroscientist who designed the study, fed a small group of healthy rodents a broth infused with Lactobacillus rhamnosus, a common bacterium that is found in humans and also used to ferment milk into probiotic yogurt. Lactobacilli are one of the dominant organisms babies ingest as they pass through the birth canal. Recent studies have shown that mice stressed during pregnancy pass on lowered levels of the bacterium to their pups. This type of bacteria is known to release immense quantities of GABA; as an inhibitory neurotransmitter, GABA calms nervous activity, which explains why the most common anti-anxiety drugs, like Valium and Xanax, work by targeting GABA receptors.
Cryan found that the mice that had been fed the bacteria-laden broth kept swimming longer and spent less time in a state of immobilized woe. ‘‘They behaved as if they were on Prozac,’’ he said. ‘‘They were more chilled out and more relaxed.’’ The results suggested that the bacteria were somehow altering the neural chemistry of mice.
Until he joined his colleagues at Cork 10 years ago, Cryan thought about microbiology in terms of pathology: the neurological damage created by diseases like syphilis or H.I.V. ‘‘There are certain fields that just don’t seem to interact well,’’ he said. ‘‘Microbiology and neuroscience, as whole disciplines, don’t tend to have had much interaction, largely because the brain is somewhat protected.’’ He was referring to the fact that the brain is anatomically isolated, guarded by a blood-brain barrier that allows nutrients in but keeps out pathogens and inflammation, the immune system’s typical response to germs. Cryan’s study added to the growing evidence that signals from beneficial bacteria nonetheless find a way through the barrier. Somehow — though his 2011 paper could not pinpoint exactly how — micro-organisms in the gut tickle a sensory nerve ending in the fingerlike protrusion lining the intestine and carry that electrical impulse up the vagus nerve and into the deep-brain structures thought to be responsible for elemental emotions like anxiety. Soon after that, Cryan and a co-author, Ted Dinan, published a theory paper in Biological Psychiatry calling these potentially mind-altering microbes ‘‘psychobiotics.’’
It has long been known that much of our supply of neurochemicals — an estimated 50 percent of the dopamine, for example, and a vast majority of the serotonin — originate in the intestine, where these chemical signals regulate appetite, feelings of fullness and digestion. But only in recent years has mainstream psychiatric research given serious consideration to the role microbes might play in creating those chemicals. Lyte’s own interest in the question dates back to his time as a postdoctoral fellow at the University of Pittsburgh in 1985, when he found himself immersed in an emerging field with an unwieldy name: psychoneuroimmunology, or PNI, for short. The central theory, quite controversial at the time, suggested that stress worsened disease by suppressing our immune system.
By 1990, at a lab in Mankato, Minn., Lyte distilled the theory into three words, which he wrote on a chalkboard in his office: Stress->Immune->Disease. In the course of several experiments, he homed in on a paradox. When he dropped an intruder mouse in the cage of an animal that lived alone, the intruder ramped up its immune system — a boost, he suspected, intended to fight off germ-ridden bites or scratches. Surprisingly, though, this did not stop infections. It instead had the opposite effect: Stressed animals got sick. Lyte walked up to the board and scratched a line through the word ‘‘Immune.’’ Stress, he suspected, directly affected the bacterial bugs that caused infections.
To test how micro-organisms reacted to stress, he filled petri plates with a bovine-serum-based medium and laced the dishes with a strain of bacterium. In some, he dropped norepinephrine, a neurochemical that mammals produce when stressed. The next day, he snapped a Polaroid. The results were visible and obvious: The control plates were nearly barren, but those with the norepinephrine bloomed with bacteria that filigreed in frostlike patterns. Bacteria clearly responded to stress.
Then, to see if bacteria could induce stress, Lyte fed white mice a liquid solution of Campylobacter jejuni, a bacterium that can cause food poisoning in humans but generally doesn’t prompt an immune response in mice. To the trained eye, his treated mice were as healthy as the controls. But when he ran them through a plexiglass maze raised several feet above the lab floor, the bacteria-fed mice were less likely to venture out on the high, unprotected ledges of the maze. In human terms, they seemed anxious. Without the bacteria, they walked the narrow, elevated planks.
Credit Illustration by Andrew Rae
Each of these results was fascinating, but Lyte had a difficult time finding microbiology journals that would publish either. ‘‘It was so anathema to them,’’ he told me. When the mouse study finally appeared in the journal Physiology & Behavior in 1998, it garnered little attention. And yet as Stephen Collins, a gastroenterologist at McMaster University, told me, those first papers contained the seeds of an entire new field of research. ‘‘Mark showed, quite clearly, in elegant studies that are not often cited, that introducing a pathological bacterium into the gut will cause a change in behavior.’’
Lyte went on to show how stressful conditions for newborn cattle worsened deadly E. coli infections. In another experiment, he fed mice lean ground hamburger that appeared to improve memory and learning — a conceptual proof that by changing diet, he could change gut microbes and change behavior. After accumulating nearly a decade’s worth of evidence, in July 2008, he flew to Washington to present his research. He was a finalist for the National Institutes of Health’s Pioneer Award, a $2.5 million grant for so-called blue-sky biomedical research. Finally, it seemed, his time had come. When he got up to speak, Lyte described a dialogue between the bacterial organ and our central nervous system. At the two-minute mark, a prominent scientist in the audience did a spit take.
‘‘Dr. Lyte,’’ he later asked at a question-and-answer session, ‘‘if what you’re saying is right, then why is it when we give antibiotics to patients to kill bacteria, they are not running around crazy on the wards?’’
Lyte knew it was a dismissive question. And when he lost out on the grant, it confirmed to him that the scientific community was still unwilling to imagine that any part of our neural circuitry could be influenced by single-celled organisms. Lyte published his theory in Medical Hypotheses, a low-ranking journal that served as a forum for unconventional ideas. The response, predictably, was underwhelming. ‘‘I had people call me crazy,’’ he said.
But by 2011 — when he published a second theory paper in Bioessays, proposing that probiotic bacteria could be tailored to treat specific psychological diseases — the scientific community had become much more receptive to the idea. A Canadian team, led by Stephen Collins, had demonstrated that antibiotics could be linked to less cautious behavior in mice, and only a few months before Lyte, Sven Pettersson, a microbiologist at the Karolinska Institute in Stockholm, published a landmark paper in Proceedings of the National Academy of Science that showed that mice raised without microbes spent far more time running around outside than healthy mice in a control group; without the microbes, the mice showed less apparent anxiety and were more daring. In Ireland, Cryan published his forced-swim-test study on psychobiotics. There was now a groundswell of new research. In short order, an implausible idea had become a hypothesis in need of serious validation.
Late last year, Sarkis Mazmanian, a microbiologist at the California Institute of Technology, gave a presentation at the Society for Neuroscience, ‘‘Gut Microbes and the Brain: Paradigm Shift in Neuroscience.’’ Someone had inadvertently dropped a question mark from the end, so the speculation appeared to be a definitive statement of fact. But if anyone has a chance of delivering on that promise, it’s Mazmanian, whose research has moved beyond the basic neurochemicals to focus on a broader class of molecules called metabolites: small, equally druglike chemicals that are produced by micro-organisms. Using high-powered computational tools, he also hopes to move beyond the suggestive correlations that have typified psychobiotic research to date, and instead make decisive discoveries about the mechanisms by which microbes affect brain function.
Two years ago, Mazmanian published a study in the journal Cell with Elaine Hsiao, then a graduate student and now a neuroscientist at Caltech, and others, that made a provocative link between a single molecule and behavior. Their research found that mice exhibiting abnormal communication and repetitive behaviors, like obsessively burying marbles, were mollified when they were given one of two strains of the bacterium Bacteroides fragilis.
The study added to a working hypothesis in the field that microbes don’t just affect the permeability of the barrier around the brain but also influence the intestinal lining, which normally prevents certain bacteria from leaking out and others from getting in. When the intestinal barrier was compromised in his model, normally ‘‘beneficial’’ bacteria and the toxins they produce seeped into the bloodstream and raised the possibility they could slip past the blood-brain barrier. As one of his colleagues, Michael Fischbach, a microbiologist at the University of California, San Francisco, said: ‘‘The scientific community has a way of remaining skeptical until every last arrow has been drawn, until the entire picture is colored in. Other scientists drew the pencil outlines, and Sarkis is filling in a lot of the color.’’
Mazmanian knew the results offered only a provisional explanation for why restrictive diets and antibacterial treatments seemed to help some children with autism: Altering the microbial composition might be changing the permeability of the intestine. ‘‘The larger concept is, and this is pure speculation: Is a disease like autism really a disease of the brain or maybe a disease of the gut or some other aspect of physiology?’’ Mazmanian said. For any disease in which such a link could be proved, he saw a future in drugs derived from these small molecules found inside microbes. (A company he co-founded, Symbiotix Biotherapies, is developing a complex sugar called PSA, which is associated with Bacteroides fragilis, into treatments for intestinal disease and multiple sclerosis.) In his view, the prescriptive solutions probably involve more than increasing our exposure to environmental microbes in soil, dogs or even fermented foods; he believed there were wholesale failures in the way we shared our microbes and inoculated children with these bacteria. So far, though, the only conclusion he could draw was that disorders once thought to be conditions of the brain might be symptoms of microbial disruptions, and it was the careful defining of these disruptions that promised to be helpful in the coming decades.
The list of potential treatments incubating in labs around the world is startling. Several international groups have found that psychobiotics had subtle yet perceptible effects in healthy volunteers in a battery of brain-scanning and psychological tests. Another team in Arizona recently finished an open trial on fecal transplants in children with autism. (Simultaneously, at least two offshore clinics, in Australia and England, began offering fecal microbiota treatments to treat neurological disorders, like multiple sclerosis.) Mazmanian, however, cautions that this research is still in its infancy. ‘‘We’ve reached the stage where there’s a lot of, you know, ‘The microbiome is the cure for everything,’ ’’ he said. ‘‘I have a vested interest if it does. But I’d be shocked if it did.’’
Lyte issues the same caveat. ‘‘People are obviously desperate for solutions,’’ Lyte said when I visited him in Abilene. (He has since moved to Iowa State’s College of Veterinary Medicine.) ‘‘My main fear is the hype is running ahead of the science.’’ He knew that parents emailing him for answers meant they had exhausted every option offered by modern medicine. ‘‘It’s the Wild West out there,’’ he said. ‘‘You can go online and buy any amount of probiotics for any number of conditions now, and my paper is one of those cited. I never said go out and take probiotics.’’ He added, ‘‘We really need a lot more research done before we actually have people trying therapies out.’’
If the idea of psychobiotics had now, in some ways, eclipsed him, it was nevertheless a curious kind of affirmation, even redemption: an old-school microbiologist thrust into the midst of one of the most promising aspects of neuroscience. At the moment, he had a rough map in his head and a freezer full of monkey fecals that might translate, somehow, into telling differences between gregarious or shy monkeys later in life. I asked him if what amounted to a personality transplant still sounded a bit far-fetched. He seemed no closer to unlocking exactly what brain functions could be traced to the same organ that produced feces. ‘‘If you transfer the microbiota from one animal to another, you can transfer the behavior,’’ Lyte said. ‘‘What we’re trying to understand are the mechanisms by which the microbiota can influence the brain and development. If you believe that, are you now out on the precipice? The answer is yes. Do I think it’s the future? I think it’s a long way away.’’
Correction: June 25, 2015
An earlier version of this article described incorrectly the affiliation of Elaine Hsiao, an author of a study published in the journal Cell that linked bacteria to behavioral changes. At the time, she was a graduate student in the lab of Paul Patterson, another author of the study, not in the lab of Sarkis Mazmanian.
(Agus Judistira) In deze verbazingwekkende lezing legt Rob Knight uit waarom de bacteriën die we in ons lichaam hebben zeer bepalend zijn voor onze gezondheid, ons uiterlijk en zelfs onze voorkeuren. Ze zijn zelfs meer bepalend dan ons DNA.
De onderlinge overeenkomsten in DNA tussen twee willekeurige mensen is gemiddeld 99,9%, terwijl in het zelfde geval er gemiddeld maar slechts 10% overeenkomsten zijn in de bacteriële populatie.
Welke bacteriën we hebben hangt af van welke bacteriën in de vagina van de moeder aanwezig zijn geweest tijdens onze geboorte. Babies die geboren zijn d.m.v. een keizersnede, en dus de gang langs de vagina missen, missen de beschermende bacteriën en hebben daardoor statistisch meer last van astma, allergieën, overgewicht, etc.
Het blijkt dat gedurende ons leven ons bacteriepopulatie vrij onveranderlijk blijft, zelfs als we in een dichte gemeenschap leven met mensen van totaal andere bacteriële samenstelling. Een uitzondering is natuurlijk wanneer we bewust de samenstelling van de populatie veranderen.
In laboratoriumtesten is aangetoond dat muizen die dik zijn weer slank gemaakt kunnen worden, door de bacteriële populatie van een slanke muis of een slanke mens over te nemen.
Door de verschillende bevindingen over het belang van de bacteriën komt het wetenschappelijk team met enkele nieuwe, vooruitstrevende manieren om (ernstige) chronische ziekten te voorkomen en te genezen.
In de lezing worden ook enkele verrassende gegevens getoond waardoor we kunnen begrijpen waarom bacteriën zo bepalend zijn voor ons welzijn.
Hierna zult u nooit meer met dezelfde ogen naar gezondheid en biochemie kijken. Als gezondheid een belangrijk onderwerp is voor u, is dit een ‘must see’.
Researchers at Cornell University have successfully treated diabetic rats by engineering a strain of lactobacillus, a rod-shaped bacteria common in the human gut, resulting in up to 30 percent lower blood glucose levels. The technology could pave the way for a new treatment for both type 1 and type 2 diabetes that could one day see managing diabetes be as easy as taking a daily probiotic pill..
According to the World Health Organisation (WHO), diabetes is one of the leading causes of death and disability worldwide. In the US, the Centers for Disease Control (CDC) reports that around 29 million people have the disease, many of whom aren’t even aware they have it. The Cornell study could take us one step closer to a safe, effective way for people to control the disease.
In their proof of principle study the researchers modified a strain of human lactobacillus to secrete a protein called Glucagon-like peptide 1 (GLP-1), which helps manage blood sugar levels, and administered it orally to diabetic rats for 90 days.
The upper intestinal epithelial cells of the diabetic rats were converted into cells that acted very much like pancreatic beta cells, which in healthy people monitor blood glucose levels and secrete insulin to balance glucose levels.
The rats with high blood glucose developed insulin-producing cells within the upper intestine in numbers sufficient to replace 25 to 33 percent of the insulin capacity of nondiabetic healthy rats.
“The amount of time to reduce glucose levels following a meal is the same as in a normal rat, … and it is matched to the amount of glucose in the blood, just as it would be with a normal-functioning pancreas,” says John March, professor of biological and environmental engineering at Cornell University and the paper’s senior author. “It’s moving the center of glucose control from the pancreas to the upper intestine.”
Conversely, the engineered probiotic did not appear to affect the blood glucose levels of healthy rats.
The technology is being licensed by biopharmaceutical company BioPancreate, which is working to get the therapy into production for human use.
“Since this has not been tested in humans we do not know the extent to which it will replace needed insulin making capacity,” March told Gizmag. “It is possible that someone who currently injects insulin will not have to anymore, but it is perhaps more likely that it will be used in conjunction with other methods to maintain healthy glucose levels.”
Future work will test higher doses to see if a complete treatment can be achieved, and the team is looking at many avenues for improving this technology for both diabetes and several other diseases, says March.
Diatomist Kemp dankt zijn titel aan de eencelige algen diatomen of kiezelwieren, waar er ongeveer 100.000 verschillende vormen en kleuren van bestaan. Kemp interesseerde zich in diatomen – net als de vroegere wetenschappers – omdat zij zich bedekken met juweelachtige kristalschelpen, die glinsterend oplichten onder een microscoop. Klemp gebruikt een ouderwets analoge setup om zijn diatomen te rangschikken als mandala’s: een microscoop en een pincet. De gedetailleerde patronen zijn een resultaat van zijn ongelofelijke behendigheid, geduld en de natuurlijke schoonheid van de geometrische schelpvormen.
Volgens Klemp komen deze fascinerende eencelligen vrijwel overal in de natuur voor. “Het maakt niet uit of het een paardentrog is, of een greppel of een goot. Je kan het zo gek niet verzinnen, waar er water is, is het de moeite waard te gaan kijken,” zegt hij in de korte documentaire van Matthew KillipThe Diatomist. In de film laat Killip Klemps herontdekking van de kunst zien, net zoals het tijdrovende proces van de diatomen verzamelen, schoonmaken, bewaren en rangschikken.
Geniet hieronder van Kemps zorgvuldige werk, veel van deze werken passen makkelijk op het hoofd van een slak. En bekijk ook de volledige documentaire van Metthew Killip over de man achter deze microstructuren, The Diatomist.
Verse bijenhoning vertoont echt een antibacteriële werking, en dat is is te danken aan melkzuurbacteriën in het inwendige van de bij. Die symbionten maken een metabolietencocktail aan waarmee je in principe zelfs de meest beruchte antibioticaresistente ziekenhuisbacteriën plat kunt krijgen, schrijven Zweedse onderzoekers in het International Wound Journal.
Het is tevens het eerste wetenschappelijke bewijs dát honing werkt tegen bacteriële infecties. Als zodanig wordt het al duizenden jaren ingezet als huismiddeltje maar niemand wist ooit of het echt iets deed – en anno 2014 doet het inderdaad niets meer omdat die melkzuurbacteriën allang dood zijn eer de honing de consument bereikt.
Een jaar of tien geleden ontdekten de Zweden al dat de honingmaag van bijen een uitgebreide bacteriepopulatie bevat, die in symbiose leeft met de gastvrouw. In de honing vind je diezelfde bacteriën ook terug. Inmiddels zijn ze er achter dat het gaat om dertien goed van elkaar te onderscheiden melkzuurbacteriën: negen soorten Lactobacillus en vier soorten Bifidobacterium. De onderlinge getalsverhoudingen hangen onder meer af van de beschikbare nectar, maar het lijken wel altijd dezelfde dertien soorten te zijn.
En zulke melkzuurbacteriën produceren niet alleen melkzuur, maar ook enzymen en antimicrobiële peptides plus kleine hoeveelheden van een hele reeks kleine moleculen zoals organische zuren, vetzuren, ethanol, benzeen en andere aromaten en waterstofperoxide.
De Zweden hebben nu die dertien soorten geïsoleerd uit bijen, ze elk afzonderlijk gekweekt in petrischaaltjes en gekeken wat voor metabolieten ze aanmaakten. Dat bleek van soort tot soort te verschillen. Maar elke soort bleek antimicrobieel actief, en als je ze allemaal tegelijk inzet krijg je een synergistisch effect waar tot nu toe geen enkel pathogeen tegen bestand is gebleken. Methicillineresistente Staphylococcus aureus(MRSA), Pseudomonas aeruginosa en vancomycineresistente Enterococcus (VRE) gaan er allemaal aan dood.
Het eeuwenoude volksgeloof dat honing de genezing van met name open wonden stimuleert, is dus wel degelijk ergens op gebaseerd. De Zweden hebben de bacteriekweekjes (met wat honing om ze smeerbaar te maken) uitgeprobeerd op een tiental paarden met hardnekkige wonden: ze genazen allemaal. Het vermoeden lijkt gerechtvaardigd dat dit natuurproduct een grote toekomst tegemoet kan gaan in een klinische setting.
Maar, zo voegen ze er aan toe, het werkt alleen als je honing gebruikt die zó uit de bijenkorf komt. De honing die tegenwoordig in de EU wordt verkocht is gerijpt, ingedikt en soms zelfs gesteriliseerd. Ze bevat nog hooguit 20 procent water, te weinig voor melkzuurbacteriën om te overleven, en de meeste antimicrobiële componenten zijn er tegen die tijd ook allang uitgedampt. Daar heb je dus medisch gezien helemaal niets meer aan.