The continued excessive use of antibiotics in the treatment of adults and children, changes in the method of delivery and the huge doses of drugs that are given to farm animals inevitably have an effect on our bacteria – both friendly and hostile. More than fifteen years ago, I began to think about what the consequences might be, and to articulate the idea that the loss of ancient, functionally preserved microbial inhabitants led to the “plague of modernity,” which has already been mentioned: obesity, juvenile diabetes, asthma, etc.
The following chapters examine the results of experiments carried out in my laboratory, first at Vanderbilt University and since 2000 at new York University, to confirm the hypothesis. The experiments had many unexpected twists, failures and successes, hard work and disappointments of all kinds. Nevertheless, the work continues: interesting days are no less than boring, and we really have achieved something. Some days the results are so clear and beautiful (thanks to the excellent students who are able to present their discoveries artistically) that I can not even believe in their truth. But good results come again and again, and that is why we understand that they are real. I’m hurrying as fast as I can.
My guide for thirty years is the ancient gastric bacterium Helicobacter pylori. When they were discovered, or rather rediscovered in 1979, the impact on human health was not obvious. Only later it became clear that they lead to specific diseases. But for the last eighteen years, my research has been devoted to the ways in which our health is preserved.
Causes disease and maintains health – it is very similar to the apparent contradiction, but such a dual nature is often found in nature. More than fifty years ago, microbiologist Theodore rosbury coined the term amphibiosis, a condition where two forms of life are in a relationship that, depending on the context of, may be symbiotic or parasitic. One day the body helps: let’s say, drives away intruders. The other day, he turns against it. Or both at the same time. One example is the above colonization of people with green streptococci. This process is all around us, even in our working relationships and marriages. It lies at the very heart of biology, where the action of the law of natural selection leads to a myriad of nuances in the interaction of organisms.
Amphibios is a more accurate term than commensalism. The second describes the guests who come to the dining table to eat; prepare an extra portion for them is not difficult, but the cost of maintaining the kitchen they do not participate. Until recently, such “guests” were considered microbes that live in the human body, the so-called normal flora. It is now known that amfibios Rosebery best describes the complex relationship between our bodies and living in us and on us organisms. Helicobacter pylori is the best model of such interaction known to me. By studying its biological interactions with humans, we can better understand the vast world of microbial life.
So, these are curved bacteria that occur, in fact, only in one place: the human stomach. Billions live on the wall in a thick layer of protective mucus, which is lined with the entire digestive tract, from the nose to the anus. It is a gel that helps food slip down and protects the gastrointestinal tract from digestive processes. In each part of the mucus varies in chemical composition and, importantly, in each zone lives its own kind of bacteria. The gel layer in the stomach is especially thick: it creates a barrier against the acidic environment necessary for digestion of food and fight against pathogens. This is where we find the pylori.
It has deep roots in evolution. The first primitive mammal ancestor had a single stomach, which laid the pattern for everyone else. Mice, monkeys, zebras and dolphins went in different evolutionary directions, separated and stomachs – they produce different acid, have a different composition of mucus, which is home to different germs. Today we found a lot of species of Helicobacter in animals: H. suis in pigs, H. acinonyx in cheetahs, H. cetorum – the dolphins of H. pylori in humans.
From genetic research, we know that people have been wearing pylori for at least 100,000 years – we can not look further because of the lack of the necessary methods. It can be assumed that the microbe has lived in us since the birth of the species Homo sapiens about 200 000 years ago in Africa. This is clearly a long-term relationship, not a one-night stand.
In addition, genetic analysis suggests that all modern populations of H. pylori originate from five ancient populations, two from Africa, two from Eurasia, and one from East Asia. We can track the movement along with the migration of people around the world – the body, this invisible passenger, carried in the stomachs. Research in my lab shows that when people crossed the Bering Strait about 11,000 years ago and entered the New World, there was an East Asian version. Now in the coastal cities of South America dominates the European strain – the result of mixing races after the arrival of the Spaniards. But pure East Asian strains are still found in South American Indians living in the depths of the jungle and in the highlands.
Until recently, pylori colonized almost all children in the early stages of life, forming the immune response of the stomach in ways that are beneficial to both the microbe and the child. Having settled in the body, microorganisms show remarkable resistance. Many other microbes that we come in contact with, like from a dog’s mouth or from yogurt, and viruses that cause colds, are not so resistant. They pass through us without stopping for long. But pylori has created a survival strategy for herself, even if part of the colony is taken out of the body by peristalsis. This movement, which pushes mucus, food and waste through the digestive tract and removes them from the body. Pylori is able to swim and reproduce quickly enough to maintain the population for a greater part of human life. For millennia, the bacterium successfully resisted any attacks and until recently absolutely dominated in the stomach. But nothing could have prepared H. pylori to the XX century, which is a big part of my story. However, to begin with, let’s go back a little.
In the XIX century, the first pathologists used microscopes to compare normal and abnormal tissues of sick people – with this began the medical discipline of pathology. Doctors immediately saw the difference. Normal tissues were of normal shape, very symmetrical-perfectly smooth rows of cells. But in infected, e.g., wounds, inflamed joints and the swollen appendices, was observed in white blood cells, which sometimes formed the whole leaf, similar to the view of the endless army of soldiers. In other cases, they formed a border around the ulcer, which contained tissue residues destroyed in the battle between white blood cells and the pathogen.
Such invasions, which we call inflammations, correlate with swelling, redness, heat and hypersensitivity, which are felt with infection or arthritis. Sometimes the inflammation is very large, such as with an abscess. In other cases, hardly noticeable, as, for example, in the muscles that hurt the day after a serious workout.
These same the first pathologists and clinicians peeked and in stomach, where virtually have all saw a huge number of bacteria, bent like comma or rolled in S-shaped spiral. But they required peculiar conditions for growth, they could not be isolated in cultures that microbiologists usually use in Petri dishes. Because these organisms could not be grown in laboratories, unlike many other gastrointestinal microbes, they could not be identified, which is why they were ignored and considered normal commensals that everyone has. After what and at all forgotten.
After a few decades, doctors began to teach that the stomach is sterile and completely free of bacteria. Of course, it was necessary to find the reason why the organ, located in the neighborhood with a rich intestine of microorganisms, they are not. Completely forgetting about the strange curved microbes, the professors came up with a reason. Since gastric juice is about the same strong acid as from the car battery, it begs a logical conclusion: in such an environment, nothing can live. Then looks at the microcosm was limited; we had no idea that bacteria could live and thrive in volcanoes, hot springs, granite, deep-sea geysers, and salt plains.
In addition, doctors knew that too acidic environment in the stomach leads to problems. It can be injured, inflammation can develop. And when it is too strong, the surface of the stomach wall can break, and get an ulcer. This disease, which is also able to form in the duodenum, which begins with the small intestine, causes severe pain. The blood vessel can suffer, than strong, sometimes deadly, bleeding is caused. Or the wall of the stomach is torn, forming a perforation that connects the inner part of the body with the usually sterile space of the abdominal cavity. In the old days from a perforated ulcer, often died. Between meals and night hours, patients with ulcers feel aching or burning abdominal pain, suffer from nausea and bloating. Ulcers can stay long, and can disappear and return.
In 1910, the German physiologist Dragutin Schwartz discovered that acidic environment is necessary for its formation. In the elderly, the acid in the stomach which broke naturally, ulcers were not formed. The scientist concluded: no acid – no ulcer. So doctors “found” the best ” way to cure an ulcer – to reduce acidity. Generations of patients have been advised to drink milk, take antacids, or have surgery that interfered with stomach acid production. In addition, under stress, the suffering increased-it is considered an explanation for why the disease disappear and return. People were urged to control not only acidity, but also emotions. When I was a medical student, I was taught that men with ulcers have problems with their mothers. So this is one of the best examples of psychosomatic disease. This lecture was given by an outstanding psychiatrist who used psychotherapy in the treatment of this disease. Each popular remedy had its own important limitations, so the peptic ulcer, as it was called, remained a big problem.
Then, in 1979, Dr. Robin Warren, a pathologist from Perth, Australia, again noticed bacteria in the gastric mucosa. Using conventional, and then specialized dyes, saw microorganisms in the form of a comma and the letter “S”. In addition, I noticed that on the walls of the stomachs of people who have these bacteria, under the microscope there are signs of inflammation. Pathologists like Warren used to call him gastritis. Almost a century later, after the first discovery of bacteria in the stomach, the scientist realized that this internal organ is still not sterile, which is why inflammation occurs. But what are these bacteria? Why they didn’t kill the gastric juice?
A few years later he shared his observations with Dr. Barry Marshall, a young Intern who also had his own “Eureka”. Reading medical literature, he noticed that almost everyone who suffered from peptic ulcer, was also gastritis. If the germs are associated with gastritis, he decided, so can be associated with an ulcer. And can even cause it.
Two scientists examined biopsies of patients with and without ulcer. Almost all patients were found and S-shaped bacteria, and gastritis. But many healthy people also had gastritis and bacteria. Scientists have concluded that the mysterious microorganisms-a necessary but not sufficient condition for the formation of ulcers, as well as increased acidity.
Doctors (including me) were taught that gastritis is a pathological inflammation of the stomach. But now, looking back, I wonder: is it a pathology or a normal state of an organ that reacts to coexistence with bacteria? Soon we will return to this difference – it is not just formal, but also the key to understanding our relationship with pylori.
In April 1982, using methods developed over the past few years to isolate Campylobacter organisms from stool samples {106}, Warren and Marshall were able to grow a culture of S-shaped bacteria for the first time. They managed to do what German, Dutch and Japanese scientists failed to do a century before. As mentioned in the first Chapter, the name was first GIT – “gastric Campylobacter-like organism”, then – Campylobacter pyloridis, then – Campylobacter pylori. A few years later, after more thorough research, it became clear that this is not Campylobacter, and their previously unknown relatives. It was then that the bacteria were called: Helicobacter pylori. A few months after the first publication of Warren and Marshall’s article in Lancet, other scientists began to find “new” organisms in the stomachs and confirm their connection with gastritis.
But Marshall wanted to prove that they caused an ulcer, not just live as passengers, so he used himself as a Guinea pig in 1984. When the test showed that there was no pylori in his stomach, he drank the culture of this organism. Nothing happened at first. But a few days later began indigestion. A new biopsy showed the presence of bacteria. And, more importantly, began gastritis: stomach ache, bad breath.
A few days later, a new biopsy showed that gastritis is almost gone. But because the scientist was worried about his body, he took an antimicrobial agent – tinidazole – just in case, and judging by further publications, he was never disturbed by pylori.
The experiment showed that the bacterium causes gastritis, and not just thrives in favorable conditions. But acute gastritis manifested itself only a few days, after which he passed. The disease was not like the usual chronic gastritis, which has been present in the stomachs of humans for decades. In addition, Marshall took antibiotics, which we now know to be, ineffective in the fight against H. pylori when taken alone. So, looking back, it’s clear that the infection started spontaneously and ended just as spontaneously. And, more importantly, a stomach ulcer, the scientist has not begun.
Nevertheless, a dramatic experiment convinced many skeptics that this common organism is indeed a pathogen. Because H. pylori causes inflammation, then it is a bad germ. Most people have the experiment remained in the memory of the picture as”crazy, but brave Australian drank culture of bacteria, and he began an ulcer, than he proved his theory.” This was of course untrue, but the attention of the world to attract managed.
To test, plays a direct role in the development of gastric ulcer or just present at it, Marshall and Warren began to treat some patients with drugs with bismuth (antibacterial agent), and others – without it. The results were obvious: those who received bismuth, relapse occurred much less frequently. Other scientists received similar results.
Now doctors could treat the ulcer with antibacterial agents, including antibiotics. It was revolutionary. Stomach ulcer was curable. Goodbye, stress, Hello, germs.
In 2005, Marshall and Warren received the Nobel prize in physiology or medicine for the isolation of H. pylori in pure culture, the discovery of its Association with gastritis and peptic ulcer, and the modification of treatment methods for peptic ulcer. This recognition has finally fixed in the minds of the idea that it is a dangerous human pathogen, and anyone who has it in the stomach, will not live very comfortably.
But many mysteries remained unsolved. Why does peptic ulcer develop in men much more often than in women, although pylori occurs in the stomachs with the same frequency? Why, despite the fact that the bacterium lives in us all life, the disease manifests itself only in the third ten, goes to the peak in the next twenty years, and then goes on a decline?
Why does it appear, then in a few days or weeks it heals, and then in a few weeks, months or years it returns? Finding a link with pylori, we have learned to treat ulcer disease and prevent its recurrence, but still know very little about the biology of the disease.
When I first saw the work of Warren and Marshall at the international conference on Campylobacter infections in Brussels in 1983, I was skeptical, especially about Marshall’s statements. Yes, they did find a new microorganism, but his words about the ulcer were not very convincingly confirmed by the evidence presented. Nevertheless, the scientist and his colleagues continued to find new evidence of the connection of bacteria with gastritis and ulcer, so together with my laboratory I decided to take part in the research. In 1985, they began to study the organisms themselves (then still considered campylobacteria) and found that they are quite diverse. But in those whose stomachs microorganisms live, antibodies are produced in the blood.
In 1987, I and my long-time co-author Guillermo Perez developed the first blood test to accurately determine the antibody carriers of H. pylori {109}. Like most scientists, we conducted an experiment on ourselves. My analysis was positive. I admit I was quite surprised. Like most carriers, there were no symptoms. My stomach is fine, although I felt a little nauseous when I heard the results. This has opened up many opportunities for us. It was possible to obtain blood samples from people of all ages from all over the world, sick and healthy, using our analysis to determine whose stomachs are hiding bacteria, and try to track the relationship with various diseases.
I wanted to know why only some carriers develop ulcers. We have shown that the strains of H. pylori are quite diverse, but did not know how this diversity affects the production of a particular strain of peptic ulcer. For example, most of us are carriers of the bacteria E. coli (coli), which is mostly harmless. Only very few of its types are dangerous because they carry genes encoding special proteins called virulence factors. They cause diseases. We were wondering if any strains had these same virulence factors. Could the difference between them explain why some get sick and others don’t? Have you identified a variety of clinically important?
After two years of research into H. pylori has been found a protein that came in all points of. It is almost always present in strains that are found in the stomachs of people with ulcers. In healthy was present in 60 % of cases. The condition was again necessary, but not sufficient. Nevertheless, it was important evidence. Can we find the gene encoding this protein? In 1989, the “library” of genes in cells of pylori was created. This means that we used coli as microscopic factories for the production of these proteins. Each cell produced only one or two of 1600 (approximately). We then took a human serum with a positive test for the microbes (again, I had it) and ran a library screening to see if any of the proteins that are producing the E. coli proteins that are recognizing my antibodies. In other words, went fishing, and caught a large prey. The first recognized clone encoded the same protein associated with peptic ulcer disease. We called it CagA – by the abbreviation “cytotoxin-associated gene” (cytotoxin-associated gene).
Later it became clear how clever these microbes are. Virulent strains contain a cluster of genes that not only produce active proteins like CagA, but also form a system for injecting them from bacterial cells into host cells. This meant that my cells of H. pylori CagA protein is produced and continuously injected into the cells of the stomach wall. Hence the inflammation, which, from my then point of view, was not good.
The second discovery is that in all strains there is a pylori protein, which, if contained in sufficient quantities, punches holes in the epithelial cells that line the stomach wall. Some of them are wider than others. In this situation, the protein is released, which is called VacA.
Having studied the works of Marshall and Warren on the connection of pylori with peptic ulcer and gastritis, we decided to consider another possible option: whether the microbe is associated with cancer of the human stomach – its main scourge. It’s terrible. After diagnosis, the patient’s chances of living for at least another five years do not exceed 10 %. In 1900, the death rate of this disease was in the US in the first place among all cancers. It still ranks second in cancer mortality in the world, second only to the lungs.
In 1987, we tried to convince the national cancer Institute to conduct a joint study on the relationship of H. pylori with gastric cancer, but we were refused. Two years later, I was contacted by Dr. Abraham Nomura, head of the Japan-Hawaii cancer research center in Honolulu. He and his colleagues pioneered the study of the risks of diseases that await Japanese-Americans living in Hawaii. The scientist asked permission to use our analysis to study the risk of stomach cancer in the presence of pylori. I jumped at the chance.
In 1965-1968, more than 7,400 Japanese-American men born in 1900-1919 enrolled in the Honolulu Cardiology research center. Veterans of the 442nd regiment, who fought valiantly on the side of the United States in world war II, have been heroes to me ever since I read James Michener’s book Hawaii about them as a child. When employees living on the West coast of the United States were placed in correctional camps, these people risked their lives and health (some lost either one or the other) to protect the country. One of them was the late Senator Daniel Inoui.
By 1989, nearly 6,000 of these veterans had been able to collect and freeze blood samples. By this time, at least 137 had developed stomach cancer; 109 were available for study. We compared them to the 109 men who had no gastric cancer, and tested the blood for antibodies to H. pylori. One of the achievements was that blood samples were collected on average more than twelve years before the diagnosis of “cancer”. Such a time period could serve as evidence of a causal relationship.
We were interested in two simple questions:who lived in the stomach of pylori already in the 60s, and who influenced the subsequent development of cancer?
The results were stunning. We found that the long-standing owners of H. pylori gastric cancer in the last 21 years evolved six times more often. I presented this discovery as a “belated breakthrough” at the same conference that Marshall had presented his data on peptic ulcer eight years earlier. Parallel studies conducted in California and England, gave the same result. Later we learned that the native strains with the cagA protein, the risk is higher in two times.
It soon became clear that pylori was in the stomach for a reason. His presence was a prerequisite for the development of cancer. In 1994, based, among other things, on our work, the world health organization declared the class I carcinogen to H. pylori because of its Association with the disease. It turned out as with Smoking and lung cancer: in the presence of a causal relationship there was no doubt.
It is not surprising that the world may believe, “the only good Helicobacter pylori a dead Helicobacter pylori”. From peptic ulcer to cancer, everything indicated that the bacterium was harmful to humans. Doctors began to look for it in patients with any symptoms of diseases of the gastrointestinal tract, and, if found, destroyed by courses of antibiotics. This was partly justified by the fear of cancer, partly by the need to cure the symptoms. But with the exception of peptic ulcer disease, clinical trials have shown no improvement except for the occasional one. Nevertheless all happily destroyed the H. pylori, barely finding her.