Season 2 - Episode 1

Helpful Links

The Northwestern Digestive Disease Center provides integrated programs to prevent, diagnose, and treat disorders of the digestive tract and associated organs. 

Donate here: ⁠https://nmgive.donordrive.com/index.cfm?fuseaction=donate.event&eventID=1171

Transcript

Gut Microbiome: 

Hello, welcome to mirroring medicine with Kodi and Isabel! Today we will be discussing the human gut and its prospective microbiome. This includes going over the intricacies through famous cases of the bacterial species of the gut microbiome and definitions of what are probiotics and antibiotics. 

This podcast is meant to provide an overview and it is not comprehensive, we will be going over the tip of the iceberg in regards to this topic and we recommend the audience researching this topic even further. 

Origins of Life: 

So starting off our podcast, I would like to introduce the idea of what a bacteria actually is. The exact scientific definition according to the NIH is that bacteria are single-celled organisms in which they come in various shapes. Some are pathogenic - meaning that these would cause disease, however there is some good bacteria to help aid in regular bodily processes. Fun fact, we have 10x more bacterial cells than we have human cells. Most bacteria are harmless, some helpful, and some cause disease. [1]

Bacteria is different from Eukarya. Eukaryotes are organisms that contain a nucleus and membrane bound organelles. Can either be single celled or multicellular. These differ from prokaryotes in which bacteria are classified because eukaryotes have internal membranes separating eukaryotic cells from the cytoplasm. Additionally, some examples of eukaryotes that you may know are animals, humans, and plants. These are bigger than the traditional bacteria (prokaryote). [2]

Probiotics Vs. Antibiotics:

What is the difference between probiotics and antibiotics? So probiotics, according to the mayo clinic, are foods/supplements that contain live organisms intended to maintain or improve “good” bacteria in the body. These can also contribute live, beneficial microbes to the populations within your gut and elsewhere, in order to strengthen those communities. These good bacteria are bacteria that allow for the smooth physiological processes to occur like a well-oiled engine. Probiotics are foods that are fermented like yogurt or kimchi or kombucha. This is known for the survival of the bacteria. Additionally, there is another word also known as prebiotics, in which it is foods containing a high amount of fiber so that it can improve the balance in your system also known as the body. These function as kind of like a food source for the bacteria. Some foods that are known as prebiotics are found in foods like whole grains, bananas, greens, onions, soybeans, garlic, and artichokes according to the mayo clinic. [3 & 4]

Antibiotics, on the other hand, are usually medications given to prevent the spread or growth of bacteria. This can include dangerous ones, good ones, or even regular non-impacting bacteria. Additionally, antibiotics are used a lot within the medical field and scientific field alike. A way that scientists actually prevent the spread of unwanted bacteria is through the placement of antibiotic treatment of bacterial cells without the antibiotic resistance marker gene. Antibiotics in the medical perspective are medicines that fight bacterial infections in people and animals, working by killing bacteria or making it hard for bacteria to grow and multiply according to medline plus. Furthermore, antibiotics can be taken in different ways: orally, topically (on the skin), or through injection or IV. Antibiotics should not be confused for antivirals. Antibiotics only treat bacterial infections but not viral infections. [5]

Charity of the Podcast:

The Northwestern Digestive Disease Center provides integrated programs to prevent, diagnose, and treat disorders of the digestive tract and associated organs. This organization conducts research on conditions such as colon cancer, gastroesophageal reflux disease, hepatitis and chronic liver disease, inflammatory bowel diseases like Crohn's disease and ulcerative colitis, and irritable bowel syndrome.

The center aims to study the impact of environmental factors, including lifestyle and the microbiome, on disease causation and treatment. You can support the digestive health program at Northwestern directly through their website via the link in the description.

Changes in the Microbiome Overtime

How does one acquire a gut microbiome? This process, known as inoculation, begins at birth and influences the maturation of the immune system, nutrient absorption, metabolism, and the prevention of pathogen colonization. To simplify, the beneficial bacteria, fungi, and archaea in your gut promote good health, while harmful pathogens can disrupt this balance, potentially leading to dysbiosis.

Research has attempted to quantify the impact of the gut microbiome on health. As of 2024, it is known that negative changes in the gut microbiome throughout life can lead to both short- and long-term consequences, such as overweight and obesity, atopic manifestations, asthma, metabolic syndromes, and chronic inflammatory diseases (Derrien et al., 2019).

Interestingly, studies on infants have shown that gut microbiota composition differs between formula-fed and breastfed infants. Breastfed infants exhibit higher levels of Bifidobacterium species, which are the most abundant and thrive on human milk oligosaccharides (HMOs). Research on the microbiome of children in Venezuela, Malawi, and the United States has also indicated significant gut microbiome maturation during the first three years of life, with high levels of inter-individual variation in all populations. This means there is substantial person-to-person variation (Derrien et al., 2019).

Overall, this highlights the idea that diet plays a crucial role in shaping the gut microbiome. The microbiome is a dynamic and constantly evolving part of the body, directly influenced by what you eat and the environment you are exposed to.  

Dysbiosis

(Cleveland Clinic) Dysbiosis is defined as an imbalance of microorganisms living in the body. The goal is to maintain a balanced microbiome in which no bacteria, virus, or fungus dominates. When a “bad” pathogen takes over the microbiome, it can lead to various issues, including gastrointestinal diseases such as H. pylori infection, C. difficile infection, small intestinal bacterial overgrowth, inflammatory bowel disease, diarrhea, constipation, and gas.

Beyond these gastrointestinal issues, the gut microbiome is believed to interact with the immune system, nervous system, and endocrine system. Other common conditions associated with microbiome dysbiosis include food intolerances, irritable bowel syndrome, fatty liver disease, metabolic syndrome, and many more.

The future of this research

In recent years, fecal transplants to alter the gut microbiome have become a hot topic. Fecal microbiota transplants (FMTs) involve the transfer of feces from a healthy donor into an animal’s gut to combat pathogens and promote microbial recovery.

Just three days ago, at the time of this recording, a study published in Nature by Bornbusch et al. revealed promising findings about FMTs in cheetahs. The study showed significant recovery of gut flora after gut infections, antibiotic treatment, and microbiota alterations caused by captivity.

In humans, a common concern is the alteration of the gut microbiome following antibiotic use. Currently, FMTs are approved for use in cases of C. difficile infections in humans. The general understanding is that FMTs facilitate the recovery and re-stabilization of disrupted microbial communities.

This particular study examined 21 healthy, ex-situ cheetahs divided into four groups:

6 untreated controls

5 treated with antibiotics alone (a 7-day course of doxycycline)

5 treated with antibiotics followed by a single FMT

5 treated with antibiotics followed by three bi-weekly FMTs

The results showed that antibiotic treatment reduced bacterial richness and evenness but did not significantly affect phylogenetic diversity.

Bacterial richness refers to the total number of different bacterial species in an ecosystem.

Bacterial evenness refers to the relative abundance of each species in the ecosystem.

The study found that in the antibiotic-treated groups receiving multiple FMTs, bacterial richness remained decreased after the second FMT. However, the groups receiving only one FMT recovered bacterial richness more effectively.

While these findings are intriguing, we cannot assume the results will directly apply to humans, as research has shown significant differences in gut microbiomes between carnivorous and omnivorous animals. It is believed that omnivorous gut microbiomes are more resilient to changes in diversity and richness due to the wide variety of foods consumed, whereas carnivores may experience larger impacts from changes in their gut environment.

Nevertheless, this study underscores how complex and rapidly evolving this field is. The future of treating digestive issues might one day rely on innovative interventions like FMTs.

Conclusion:

In conclusion, the gut microbiome plays a vital role in our overall health. Bacteria exist in every environment we interact with and are also an integral part of us. Today, we explored the roles of probiotics in health and how antibiotics can alter the gut microbiome. We highlighted the importance of gut inoculation in early life and discussed how gut dysbiosis can occur. Lastly, we touched on current research in this field and speculated on where future studies might lead.

Be sure to check out the Northwestern Digestive Disease Center, which is pioneering research in this area. We hope you enjoyed this episode, and we’ll see you next time!

Citations

1. National Human Genome Research Institute. "Bacteria." Genetics Glossary, www.genome.gov/genetics-glossary/Bacteria. Accessed 31 Dec. 2024.

2. Nature Education. "Eukaryote (Eucariote)." Scitable by Nature Education, www.nature.com/scitable/definition/eukaryote-eucariote-294/. Accessed 31 Dec. 2024.

3. Mayo Clinic Staff. "Probiotics: What You Need to Know." Mayo Clinic, www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/probiotics/faq-20058065. Accessed 31 Dec. 2024.

4. Cleveland Clinic Health Essentials. "What Are Prebiotics?" Cleveland Clinic, health.clevelandclinic.org/what-are-prebiotics. Accessed 31 Dec. 2024.

5. MedlinePlus. "Antibiotics." MedlinePlus, medlineplus.gov/antibiotics.html. Accessed 31 Dec. 2024.

6. Derrien, Muriel, Anne-Sophie Alvarez, and Willem M. de Vos. "The Gut Microbiota in the First Decade of Life." Trends in Microbiology, vol. 27, no. 12, 2019, pp. 997–1010. ScienceDirect, https://doi.org/10.1016/j.tim.2019.08.001.

7. Cleveland Clinic. "Dysbiosis." Cleveland Clinic, www.my.clevelandclinic.org/health/diseases/dysbiosis. Accessed 31 Dec. 2024.

8. Bornbusch, S. L., A. Crosier, L. Gentry, et al. "Fecal Microbiota Transplants Facilitate Post-Antibiotic Recovery of Gut Microbiota in Cheetahs (Acinonyx Jubatus)." Communications Biology, vol. 7, 2024, p. 1689. https://doi.org/10.1038/s42003-024-07361-5.