Kei Sonoyama

Exploring the Relation between Intestinal Microorganisms and Our Health

Kei Sonoyama , Associate Professor

Graduate School of Life Science, Research Faculty of Agriculture (Department of Bioscience and Chemistry, School of Agriculture)

High school : Shimane Prefectural Izumo High School

Academic background : Doctorate from Hokkaido University

Research areas
Digestive system physiology
Research keywords
intestinal microorganisms, allergy, metabolic syndrome, hibernation

What is your goal?

My goal is to prevent diseases and promote health by controlling the composition of intestinal microorganisms with food.

Figure 1. Intestinal microorganisms are
associated with the physiology of the host.

Intestinal microorganisms, with over 1,000 types in existence and numbering 100 trillion, do not live in our intestine independently but rather are deeply associated with the physiology of the host and part of our body in a sense. Therefore, the risk of various diseases also changes when the composition of the microbial community (microbiota) changes. In other words, a composition of microbiota that is able to prevent certain diseases may exist.

Food compositions that are not digested and absorbed, such as dietary fiber, affect the activity of intestinal microorganisms. In our laboratory, we aim to elucidate whether various diseases can be prevented or improved by such constitutive changes in the intestinal microbiota caused by food composition, as well as elucidating the mechanism thereof.

Incidentally, the condition of the intestines of hibernating animals, which do not intake any food at all, along with the intestinal microorganisms thereof, has not been elucidated, with few researchers worldwide studying this subject. By studying them, I believe an unknown relationship between intestinal microorganisms and the host can be discovered.


How do you conduct your research?

We conduct experiments using animals such as mice, rats, and hamsters, as well as cultured cells. In order to investigate the impact of intestinal microbial changes on diseases, we use animal models with various diseases including allergies (atopic dermatitis; Figure 2), autoimmune diseases (rheumatoid arthritis; Figure 3), and metabolic syndromes (obesity; Figure 4, diabetes mellitus).

Figure 2. Atopic dermatitis model mouse

Figure 3. Rheumatoid arthritis model mouse

Figure 4. Obese model mouse (left)

Figure 5. Dormant Mesocricetus auratus


Figure 6. Endoscopic observation of the intestine of Ursus thibetanus japonicus.


In addition to Mesocricetus auratus (Figure 5), Ursus thibetanus japonicus are also used as dormant animals. An endoscope is inserted into the anus of an anesthetized bear, allowing videography of the intestine and collection of intestinal mucosa tissues (Figure 6).

Blood and various tissue samples from these animal models are collected, after which we analyze the composition thereof, observe them with a microscope, or measure the gene expression levels. Moreover, in some cases, cells are segregated from the collected tissues and cultured. Of course, intestinal microorganisms may be investigated upon cultivation; however, recently they are usually molecular biologically analyzed based on differences in the base sequence of genes.

Figure 7. Scanning electron microscopic image of the small-intestinal mucosa of a hamster (left) and the optical microscopic image thereof (right)

Figure 8. Lactobacillus (green) incorporated into the cecal lymph nodes (blue) of a mouse



What is your next goal?

Intestinal microorganisms are deeply associated with the physiology of the host, i.e., our body. For example, intestinal microorganisms may be associated with immune system disorders such as allergies and autoimmune diseases, because of their significant role in developing and modulating the immune system. An enormous number of unknown relations between intestinal microorganisms and the physiology of the host are expected to exist. Our goal is to discover the roles of unrecognized intestinal microorganisms and achieve greater human well-being.