OHIO STATE UNIVERSITY
We know that what happens in the mouth does not stay in the mouth, but the connection of the oral cavity with the rest of the body goes beyond chewing, swallowing and digesting.
The healthy human oral microbiome consists not only of clean teeth and firm gums, but also of energy-efficient bacteria that live in a blood vessel-rich environment that allows constant communication of the organisms with the cells and proteins of the immune system.
A growing body of evidence has shown that this system that seems so separate from the rest of our bodies is actually very influential and influenced by our overall health, said Purnima Kumar, professor of periodontology at Ohio State University, speaking at a conference. of science this week.
For example, type 2 diabetes has long been known to increase the risk of gum disease. Recent studies showing how diabetes affects bacteria in the mouth help explain how periodontitis treatment that changes oral bacteria also reduces the severity of diabetes itself.
Connections have also been found between oral microbes and rheumatoid arthritis, cognitive abilities, pregnancy outcomes, and heart disease, supporting the idea that a sick mouth can go hand in hand with a sick body.
"What happens in your body impacts your mouth, and that in turn impacts your body. It’s really a life cycle," Kumar said.
When the American Association for the Advancement of Science (AAAS) introduced this year’s annual meeting theme around dynamic ecosystems, Kumar saw an opportunity to put his mouth on the map, so to speak, as a vibrant microbial community. that can tell us a lot about ourselves. .
"What’s more dynamic than the gateway to your body: the mouth? It’s so overlooked when you think about it, and it’s the most forward-facing part of your body that interacts with the environment, and is connected to this entire system of tubes," she said. "And yet, we study everything except the mouth."
Kumar hosted a session at today’s (February 8, 2021) AAAS meeting titled "Killer Smile: The Link Between the Oral Microbiome and Systemic Diseases."
The oral microbiome refers to the collection of bacteria, some useful to humans and some not, that live inside our mouths.
Kumar has led and collaborated on recent research that further explains the link between oral health and type 2 diabetes, which was first described in the 1990s. She was the lead author of a 2020 study that compared microbiomes of people with and without type 2 diabetes and how they responded to non-surgical treatment of chronic periodontitis.
Subgingival host-microbial interactions in hyperglycemic individuals Summary Type 2 diabetes mellitus (T2DM) is an established risk factor for periodontitis, however, its contribution to creating a host-bacterial imbalance in the subgingival cleft is poorly understood. The present investigation aimed to quantify the impact of hyperglycemia on host-bacterial interactions in established periodontitis and to map changes in these dynamics after non-surgical mechanical therapy. 17 subjects with T2DM and 17 without T2DM with severe generalized chronic periodontitis were recruited along with 20 periodontally healthy individuals. Subjects with periodontitis were treated with scaling and root planing (SRP). Subgingival biofilm and gingival crevicular fluid samples were collected at baseline and at 1, 3, and 6 months postoperatively. Correlations were generated between 13.7 million 16S ribosomal DNA sequences and 8 immune mediators. Intermicrobial and host-microbial interactions were modeled using differential network analysis. Periodontal health was characterized by a sparse interbacterial and highly connected cytokine-bacteria network, while both normoglycemic and T2DM subjects with periodontitis demonstrated strong congeneric and intergeneric centers, but significantly fewer cytokine-bacterial connections. After SRP, cytokine-bacterial borders demonstrated a 2-fold increase at 1 month postoperatively and a 10-fold increase at 6 months in normoglycemics. In hyperglycemic patients , it doubled after a month but there were no further changes thereafter. These changes are accompanied by an increasingly sparse interbacterial network. In normoglycemics, ganglia anchored by interleukin (IL)-4, IL-6, and IL-10 showed increased rewiring, while in hyperglycemics, IL-1β, IL-6, INF-γ, and IL-17 exhibited progressive rewiring. . Therefore, the present investigation points to a breakdown in bacterial-host mutualism in periodontitis, with interbacterial interactions rather than bacterial interactions primarily determining community assembly. Hyperglycemia further exacerbates this uncoupled mutualism. Our data also demonstrate that, while nonsurgical therapy may not consistently alter microbial abundance or reduce proinflammatory molecules, it "resets" the interaction between the immune system and the newly colonizing microbiome, restoring the role of the immune system in determining bacterial colonization. However, this result is lower and delayed in hyperglycemic patients. |
The team discovered that periodontitis allows bacteria, rather than the human host, to take over the kidneys to determine the mix of microbes and inflammatory molecules in the mouth. Treatment of gum disease led to the eventual restoration of a normal host-microbiome relationship, but it occurred more slowly in people with diabetes.
"Our studies have led to the conclusion that people with diabetes have a different microbiome than people who are not diabetic," Kumar said. "We know that changing the bacteria in your mouth and restoring it to what your body knows as healthy, friendly bacteria actually improves your glycemic control."
Although much remains to be learned, the basics of this relationship between the oral microbiome and systemic disease have become clear.
Oral bacteria use oxygen to breathe and break down simple carbohydrate and protein molecules to stay alive. Something as simple as not brushing your teeth for a few days can trigger a cascade of changes, disrupting oxygen supply and causing microbes to shift into a fermentative state.
