La microbiota intestinal o por qué "hay un amigo dentro de mí"

Gut Microbiota: You’ve Got a Friend in You

21.1.2021
Stool Story bacterias
Photo: Arek Socha / Pixabay

The terms "microbiota" and "microbiome" have risen from obscurity in recent years, taking on a pivotal role in marketing strategies in the food and cosmetics industries. Slogans like "Boost your microbiome" and "Good for your microbiota" are now commonplace in advertisements for many products. But what do these terms mean and why are they so trendy?

The first thing you need to understand is that microbiota and microbiome are not synonyms, even though people sometimes get them mixed up or use them interchangeably. Microbiota refers to all the microorganisms—mainly bacteria, viruses and fungi—that inhabit a specific part of the body, whereas microbiome refers to all the genetic material contained within that community.

Our bodies provide a habitat for trillions of microorganisms that are essential to our existence. They live all over our skin and mucous membranes, protecting these surfaces and helping to maintain their properties. The largest such community of microorganisms—known as the gut microbiota or faecal microbiota—lives in our intestines (mainly the colon). Although the gut microbiota has been studied for quite some time, the association between these microorganisms and health was discovered only relatively recently.

Although the gut microbiota has been studied for quite some time, the association between these microorganisms and health was discovered only relatively recently

The millions of microorganisms that make up a person’s gut microbiota represent more than 1,000 different species and can weigh up to two kg. They perform essential functions such as breaking down our food to obtain key nutrients and producing vitamins and substances essential to our metabolism, as well as playing a fundamental role in the regulation of the immune system.

We acquire our faecal microbiota at birth. Throughout our lives, it evolves with us, reflecting our lifestyle, our environment and the food we eat. It is therefore considered a "second fingerprint". Undergoing certain treatments, such as chemotherapy, or taking certain medications, especially antibiotics, can disturb the stability of this community. Occasionally, an imbalance in a person’s gut microbiota can facilitate the overgrowth of an opportunistic pathogen or allow a new pathogen to gain a foothold.

 

Photo: Nick Bondarev / Pexels

 

Nevertheless, one of the key features of our gut microbiota is resilience. In most cases, the microbiota eventually returns to its normal state and the balance is restored.

Undergoing certain treatments, such as chemotherapy, or taking certain medications, especially antibiotics, can disturb the stability of the microbiota. Occasionally, an imbalance in a person’s gut microbiota can facilitate the overgrowth of an opportunistic pathogen or allow a new pathogen to gain a foothold

But what happens if the imbalance does not go away on its own? One treatment option that has been gaining popularity is faecal microbiota transplant (FMT), also known as stool transplant. This approach restores the balance by taking the faecal microbiota from a healthy donor’s stool and transferring it to the patient’s colon. At present, the procedure is usually performed by colonoscopy or via nasogastric tube and using faeces from a relative of the patient. However, there is a growing trend towards oral administration by capsules containing faeces from universal donors.

Perhaps surprisingly, FMT is nothing new. Then known as "yellow soup", it was first used in 4th-century China to treat severe cases of food poisoning and diarrhoea. Use of the technique was recorded in the first Chinese medical manual, Zhou Hou Bei Ji Fang , by the sage Ge Hong.

With efficacy exceeding 90%, FMT is now regarded as a treatment of choice for recurrent Clostridioides difficile infection, the leading cause of infectious diarrhoea in hospitalised patients worldwide.

With efficacy exceeding 90%, faecal microbiota transplant is now regarded as a treatment of choice for recurrent Clostridioides difficile infection, the leading cause of infectious diarrhoea in hospitalised patients worldwide

More than 200 active clinical trials all over the world are currently studying the use of FMT to treat various conditions, including inflammatory bowel disease, urinary tract infections, multidrug-resistant bacteria decolonisation, metabolic diseases such as diabetes and obesity, neurological diseases and behavioural disorders.

What are the limitations of this procedure? Not all hospitals are currently able to recruit stool donors when samples are needed. Moreover, the comprehensive screening protocols in place to ensure the safety of transplant recipients reduces the size of the potential donor pool. Stool banks have emerged as a solution to this problem. These institutions select healthy donors and store stool samples, which they then supply to hospitals and other health care facilities. However, the number of stool banks worldwide remains very small. In addition, hospitals need to have a team of experts on hand to assess the need for the procedure and its potential benefit in each patient. If the route of administration is colonoscopy, the team must also include gastroenterologists capable of performing the procedure.

One of the major hurdles faced by groups working in this area is the lack of widespread knowledge about faecal donation. Besides not being widely publicised, the subject is taboo in our society, so fewer volunteers come forward to donate faeces than blood

One of the other major limitations faced by groups working in this area is the lack of widespread knowledge about faecal donation. Besides not being widely publicised, the subject is taboo in our society, so fewer volunteers come forward to donate faeces than blood. By raising awareness about the importance of the gut microbiota and its potential for treating many diseases, perhaps we can get people thinking and help them understand that donating faeces is just like any other altruistic act—a way for us to help each other.

In short, your gut microbiota could save lives. Without a doubt, "you’ve got a friend in you"!