As Charissa and I begin to plan Gut Instincts, our virtual exhibit which will be hosted by SciArt Center, I have been reviewing some of the existing literature about the gut microbiome and human health. Specifically, I have been interested in a question that I often ask my student. How do we know what we know? For this burgeoning field of research, the answer is complex.
In some cases, the link between our microbiota and our health is quite clear. As an example, let’s consider vaginal yeast infections. The usual culprit, Candida albicans, often is found in the vagina. Typically, though, it is present in small numbers and does not cause any signs or symptoms of disease. So what causes the population explosion associated with a yeast infection? Under typical conditions, other microbes present in the vagina control the growth of C. albicans. Certain resident bacteria produce acidic by-products, which lower the pH of the vagina. This low pH environment inhibits the growth of C. albicans. If the growth of these bacteria is inhibited, perhaps as a result of the person taking antibiotics for a bacterial infection, then the pH of the vagina may increase, making it more hospitable for the growth of C. albicans.
In this example, the effects of our microbial partners on our health can be demonstrated very clearly and conclusively. We can show that C. albicans is the cause of a yeast infection. We can show that C. albicans grows better in alkaline conditions. We can show that bacteria normally create a slightly acidic environment that, in turn, regulates the growth of the yeast. The data are fairly clear.
What about more complex situations? To investigate the role of gut microbes on food utilization and weight gain, Dr. Jeff Gordon and his colleagues at Washington University at St. Louis took a reductionist approach. They began their experiments with germ-free, or gnotobiotic, mice. These mice have not been colonized by microbes and are raised under germ-free conditions to prevent their colonization. Researchers can colonize these animals with specific microbes under controlled conditions and determine the effects of the introduced microbes on the health of the animals.
Gordon et al. showed that germ-free mice co-colonized with the bacterium Bacteroides thetaiotaomicron and the archaeon Methanobrevibacter smithii derived more energy from their diet than germ-free mice or mice colonized only with B. thetaiotaomicron. Based on these results, the researchers hypothesized that M. smithii increases the ability of mice to extract calories from the food that they eat. The implications for human health are significant. It might be possible to reduce obesity by decreasing the amount of M. smithii in a person’s GI tract. Conversely, M. smithii could be used in resource-poor regions to help people extract more calories from their limited food intake. This preliminary research led to another interesting observation. When comparing the microbes present in the GI tracts of lean people and people with anorexia, researchers observed significantly more Methanobrevibacter in people with anorexia. They hypothesized that this increase may reflect an adaptation by the body to maximize the usable calories in the face of a very low caloric diet.
This example, in which researchers compared the microbes present in two different groups of people, represents another approach to investigating the relationship between our microbiota and our health. In several studies, this approach has been used to examine the link between our microbiome and our behavior. Researchers, for example, have compared the microbiomes of children with autism spectrum disorder (ASD) and neurotypical children. Differences seem to exist. Moreover, in studies of mice that display some aspects of ASD, researchers have shown that oral administration of certain bacterial species to these mice alleviates some of the symptoms. Taken together, these studies provide very preliminary, yet compelling, evidence supporting the idea that the microbes in our gut can affect our behavior and cognitive functions.
These few examples provide just a glimpse into this developing field. To investigate the link between our microbiome and our health, researchers are using several different approaches, each of which provides us with different kinds of information. So let’s return to my opening question. How do we know what we know? When we are talking about the effects of our microbiome on our health, it’s complicated. In an earlier post, Charissa very eloquently wrote, “One understands the working function of any given system…in terms of a network of forces rather than looking to an element singly on its own.” This description applies perfectly to microbiome research. And it’s this complexity that I hope we can explore in our upcoming exhibition.
Art and the Brain-Gut Axis: What is an Art of the Gut Microbiome?
Dave Wessner and I are inching our way toward curating an online exhibition on the gut microbiome called Gut Instinct. We face several exciting challenges. First, do we want to present the idea to artists for their free interpretation? Or would we rather very carefully choose artists and their works and leave nothing open to chance? Do we want freely created analyses and translations of the gut microbiome? Or do we want instructional and illustrative examples? Art occupies a different place in each answer.
In the recent show Chirality: Defiant Mirror Images in Dallas at Gray Matters Gallery, I gathered artists, presented the idea, and let them freely decode and decipher it into various media and forms. By and large it was a great success, which I blogged about here last week. While there was only one artist, who sadly in bad faith went forward with his piece admitting to have never understood the concept of chirality, the others did understand the idea, make great works of art, and expand the criteria by which we understand art-and-science visualization.
For our upcoming exhibition Gut Instinct, I hope to have a mixture of both, with more work being materializations of free interpretations, conversions, and transformations of the gut microbiome and only a few being works of art that forthrightly and literally illustrate the gut microbiome.
Curating is all about presenting art that exudes, embodies, and enlivens a thesis about art, society, or the world. Bearing this in mind, and perhaps most important of all, Wessner and I must articulate our thesis. Why are we so interested in gut microbiota and the gut microbiome?
There are many reasons for me. I am fascinated by the elegant functionalism and extreme diversity of life in our gut with respect to microbiota (the actual bacteria) and the microbiome (their DNA). Our complexity pales in comparison to its. Distilling this wonderful intricacy, Margaret J. McFall-Ngai explains, “plants and animals are a patina on the microbial world.” The microbiome helps our own DNA function properly. Their health and well-being is our health and well-being.
What really gets me excited is the relationship between the brain and gut. The brain-gut axis is the information feedback loop between the gastrointestinal tract, the nervous system, and the microbiota living in the gut. The microbiota and their microbiome are connected to our mood. Disruption and disequilbrium in one area reciprocally affects the other. I would like to see a group of art works riffing on the brain-gut axis – thinking through the role of gut as the second brain and, by connection, the function of “gut instinct” as a mode of unconscious ratiocination.
The Hungarian artist László Moholy-Nagy seemed to be getting at some of this thinking a century ago. In the late 1920s, he described the creation-reception-perception of objects according to the instinctual in The New Vision:
“In every creative work there is a sphere in which a certain freedom is left to the intuition. The creative problem enters at the point where the freedom begins, where the visible function no longer determines, or at least not wholly determines, the form. In such cases an instinctive sureness of perception is required, and this is nothing more than the end result of complicated processes going on the subconscious, but in the last determined biologically.” (Moholy-Nagy, László, The New Vision (1938) (Mineola, NY: 1975) 62.)
Let us understand the word “biologically” here to connect to his interests also in the enteroceptive, the feelings “arising from the internal organs and viscera,” or what might succinctly translate into “gut instinct.” (Moholy-Nagy, 24.)