Microbes are the dominant life form of Earth. Bacterial organisms living on our planet they outnumbered all others combined. Microbes dominate not only the planet, however, but also new people. Few know that the body of each of us is 10 times more microbial cells than the cells that compose the human body, and the number of microbial genes is 150 times than that of human genes. All these beings living in our body and its surface form an ecosystem that is called “microbiome” and symbiosis of these small beings with human cells creates a true “super-organism”.
The term “microbiome” was developed by Joshua Lederberg, one of the giants of molecular biology to designate all microbes, their genetic elements and their interactions in an environment. In 1958, Lederberg became one of the youngest Nobel laureates, receiving the largest award in medicine just 33 years.
Bacteria that form our digestive tract microbiome colonized as early as 24 hours after birth and stabilized around the age of two years, becoming a permanent presence in our lives and forming a true “body”.
Our microbiome varies from birth: scientists have discovered that babies are covered with microbes naturally present in the birth canal, and those who are born by caesarean section are covered with germs that are normally on the skin of adults.
Experts estimate that trillions of microbes that live in our body weighing a total of almost 2 kg. Most of them live in the intestines, and their destruction can have unpleasant consequences, such as obesity or development of diseases of the colon.
Our relationship with bacteria that live in us is symbiotic: in exchange for food, they help us digest food, produce vitamins that we need to strengthen our immune system. To coexist with our microbiome, the immune system must tolerate thousands of species of bacteria harmless. Instead, these bacteria play an important role in the fight against pathogens – bacteria “bad”.
Knowing the microbes that live in our bodies, scientists hope to give everyone a better life through personalized diet, disease diagnosis and faster treatment of their custom.
Why are essential microbes of us
Numerous studies in recent years have shown that disruption microbiome may have unpleasant consequences for human health, among them are allergies, eczema, asthma and obesity.
In recent decades, it was observed that in industrialized areas of the planet increased number of patients with allergies in a fast pace. After years of study, researchers concluded that “obsession with cleanliness” is the main cause. The hypothesis was confirmed by a Swiss study last year in which researchers have reached a firm conclusion: the dramatic increase of allergic diseases in industrial societies is related to rapid disappearance of organisms that inhabit the human body. According to a study by experts in microbiology and immunology in the Stanford School of Medicine, people with Helicobacter pylori bacteria in the body has a lower risk of asthma, allergic rhinitis or skin allergies, compared with the other. Also, scientists say that Helicobacter pylori plays an important role in the functioning of the hormone ghrelin, the disappearance of bacteria contributing to obesity, type 2 diabetes and other metabolic disorders.
Two American researchers, Jeffrey Gordon and Ruth Ley of Washington University have conducted several experiments on mice that had interesting results. Thus, they found that mice genetically predisposed to obesity have the intestinal flora bacteria that absorb nutrients from food more than other mice in the cage. The same was observed in humans. The two researchers monitored 12 obese volunteers for one year, during which they followed a diet. As volunteers have weakened the structure of their gut bacteria changed.
Also, Gordon and Ley have shown that when mice living in a sterile environment are colonized with bacteria extracted from the body of obese mice, tend to put on weight more than when they are colonized with bacteria extracted from the body weight of mice with normal . This study seems to explain the contagious effect of obesity seen among men. Thus, obesity is not only genetically transmitted, but also socially, exchange of bacteria that occurs between friends and relatives.
So, we can say that man, being a super-organism, is like a forest ecosystem, depending on the presence of many creatures which by their diversity maintain a balance system.
The 3 enterotypes of people
Recently, a large European project called MetaHIT led to the discovery that people are different and bacteria that live in them, not only by factors such as blood group. Scientists have discovered that there are three types of microbial populations, each man of one of these enterotipuri. However, researchers found that enterotipurile unrelated to age, sex, nationality or persons diet.
The 3 enterotype dominant microbial group are named Bacteroides, Prevotella and Ruminococcus. Bacteroides type microbes are more effective in breaking down carbohydrates, which may explain why people with this enterotip are more prone to weight problems. Type bacteria Prevotella tend to break down mucus in the gut, and Ruminococcus facilitates the absorption of sugar, which can promote weight gain.
People belonging enterotipului intestinal Bacteroides have a better environment to synthesize vitamins B2, B5, C and H, and those who belong have more bacteria Prevotella enterotipului efficient synthesis of folic acid and vitamin B1.
A study last year showed that Bacteroides enterotipul is associated with diets high in fat and protein, while Prevotella enterotipul is associated with a diet rich in carbohydrates.
Another study conducted by Oluf Pedersen, a specialist in molecular genetics at Steno Diabetes Center in Gentofte, Denmark, showed that obese people or those suffering from metabolic disorders usually belonged enterotipului Bacteroides. In fact, researchers found that 90% of cases can deduce whether a person is obese or analyzing only its microbiome.
A study conducted in Denmark showed that the microbiome analysis allows physicians to predict accurately whether a patient will suffer from diabetes, multiplying microbe Bacteroides group is a better marker than body mass index of the person studied.
Enterotype discovery, another step toward personalized medicine
Scientists believe the discovery will transform medicine enterotipurilor as was done for blood groups. Enterotipului and personalized diets based on appropriate prescribing for patients are the first changes enterotipul homegrown specialists.
Also, scientists believe that enterotipurile will play an important role in finding alternative treatments to antibiotics have become ineffective in recent years, as the bacteria have become resistant. Thus, instead of trying to eliminate all bacteria in the gut, including the harmful, doctors will be useful to stimulate bacteria to restore bacterial balance existing before the disease to develop. In time, will allow development enterotipurile personalized medicine where every patient will receive treatment tailored to their needs, as identified by its microbiome.
Bacterioterapia (also known less euphemistically as “fecal transplant”) is a treatment that has already begun to be applied with encouraging results in patients for antibiotics and other treatments do not work. Bacteria transplantation is performed for decades, but only in recent years it has become possible genetic analysis of bacteria in the intestine before and after transplant.
Dusko Ehrlich, project coordinator in MetaHIT, explains why microbiome will play an important role in personalized medicine, “our genomes differ by up to 0.1% from person to person, but metagenomic difference can be 50%” . Thus, by analyzing genes organisms living in us, doctors can identify unique aspects of each patient, allowing the design of personalized treatments.
Researchers are also expected in the future, children will be vaccinated only against viruses, but will be subjected to detailed analysis of the microbiome, to be identified bacteria missing key to their return.
Research on Microbiome is still in its infancy, but doctors hope to gain a better understanding of it, to turn it into an ally against disease. Thus, bacteria that live in us will play a key role in ensuring our health, as scientists will come to understand them better.
Specialists involved in studying the potential benefits of microbiome say its understanding are enormous. Julian Davies, a microbiologist at the University of British Columbia, says that “the effort to better understand the microbiome is the most important scientific project of all time. If this project succeeds, everyone will benefit. “So coming years promise to bring remarkable news about essential beings living in super-organism.