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Long-term exposure to Porphyromonas gingivalis causes inflammation and degeneration of brain neurons in mice that is similar to the effects of Alzheimer’s disease in human beings, according to the University of Illinois at Chicago (UIC). These findings suggest that periodontal disease may be an initiator of Alzheimer’s disease, researchers there report.

“Other studies have demonstrated a close association between periodontitis and cognitive impairment, but this is the first study to show that exposure to the periodontal bacteria results in the formation of senile plaques that accelerate the development of neuropathology found in Alzheimer’s patients,” said Keiko Watanabe, DDS, professor of periodontics at the UIC College of Dentistry and corresponding author of the study.

“This was a big surprise,” Watanabe said. “We did not expect that the periodontal pathogen would have this much influence on the brain or that the effects would so thoroughly resemble Alzheimer’s disease.”

To study the impact of the bacteria on brain health, the researchers established chronic periodontitis in 10 wild-type mice. Another 10 mice served as the control group. After 22 weeks of repeated oral application of the bacteria to the study group, the researchers studied the brain tissue of the mice and compared brain health.

The mice chronically exposed to the bacteria had significantly higher amounts of accumulated amyloid beta, a senile plaque found in the brain tissue of Alzheimer’s patients. The study group also had more brain inflammation and fewer intact neurons due to degeneration.

These findings were further supported by amyloid beta protein analysis and RNA analysis that showed greater expression of genes associated with inflammation and degeneration in the study group. DNA from the periodontal bacteria was also found in the brain tissue of mice in the study group, and a bacterial protein was observed inside their neurons.

“Our data not only demonstrate the movement of bacteria from the mouth to the brain, but also that chronic infection leads to neural effects similar to Alzheimer’s,” Watanabe said.

The researchers say these findings are powerful in part because they used a wild-type mouse model. Most model systems used to study Alzheimer’s rely on transgenic mice, which have been genetically altered to more strongly express genes associated with the senile plaque and enable Alzheimer’s development.

“Using a wild-type mouse model added strength to our study because these mice were not primed to develop the disease, and use of this model gives additional weight to our findings that periodontal bacteria may kickstart the development of the Alzheimer’s,” Watanabe said.

The researchers say that understanding causality and risk factors for the development of Alzheimer’s is critical to the development of treatments, particularly when it comes to sporadic or late-onset disease, which constitutes more than 95% of cases and has largely unknown causes and mechanisms. Watanabe also said the findings offer lessons for everyone.

“Oral hygiene is an important predictor of disease, including diseases that happen outside the mouth,” she said. “People can do so much more for their personal health by taking oral health seriously.”

Routine oral care to treat periodontitis may play a role in reducing inflammation and toxins in the blood (endotoxemia) and improving cognitive function in people with liver cirrhosis, according to researchers at Virginia Commonwealth University.

Cirrhosis, which the researchers call a growing epidemic in the United States, is the presence of scar tissue on the liver. When severe, it can lead to liver failure. Complications include infections throughout the body and hepatic encephalopathy, a buildup of toxins in the brain caused by advanced liver disease. Symptoms of hepatic encephalopathy include confusion, mood changes, and impaired cognitive function.

Previous research shows that people with cirrhosis have changes in gut and salivary microbiota, which can lead to gum disease and a higher risk or cirrhosis-related complications. Also, studies have found that people with cirrhosis have increased levels of inflammation throughout the body, which is associated with hepatic encephalopathy.

The researchers studied two groups of volunteers who had cirrhosis and mild to moderate periodontitis. One group received periodontal care, including teeth cleaning and removal of bacteria toxins from the teeth and gums. The other group was not treated for gum disease. The researchers collected blood, saliva, and stool samples before and 30 days after treatment. Each volunteer took standardized tests to measure cognitive function before and after treatment.

The treated group, especially those with hepatic encephalopathy, had increased levels of beneficial gut bacteria that could reduce inflammation as well as lower levels of endotoxin-producing bacteria in the saliva when compared to the untreated group. The untreated group, on the other hand, demonstrated an increase in endotoxin levels in the blood over the same time period.

The improvement in the treated group “could be related to a reduction in oral inflammation leading to lower systemic inflammation or due to [less harmful bacteria] being swallowed and affecting the gut microbiota,” the researchers said in the study.

Cognitive function also improved in the treated group, suggesting that the reduced inflammation levels in the body may minimize some of the symptoms of hepatic encephalopathy in people who are already receiving standard-of-care therapies for the condition.

This finding is relevant, the researchers said, because there are no further therapies approved by the Food and Drug Administration to alleviate cognition problems in this population, the researchers said. The oral cavity, then, could represent a treatment target for reducing inflammation and endotoxemia in patients who have cirrhosis to improve clinical outcomes, the researchers concluded.

Aleksandra Zuk, a PhD candidate at the Dalla Lana School of Public Health, is the lead author of the study looking at link between vitamin D3, gum disease and Type 2 diabetes. Credit: University of Toronto

In a rare study of its kind, new University of Toronto research has identified how vitamin D3 and periodontitis influence Type 2 diabetes.

Aleksandra Zuk, a PhD candidate in epidemiology at the Dalla Lana School of Public Health, found increased odds of developing Type 2 diabetes among people with gum disease who are also lacking in vitamin D3.

“We know that vitamin D is not only helpful for bone health, but is also shown to have antimicrobial and anti-inflammatory effects. Sufficient vitamin D levels can potentially decrease inflammation and affect oral microbes related to gum disease,” said Zuk, the lead author on the study and a trainee at the Population Health Analytics Laboratory.

The prevalence of pre-diabetes and Type 2 diabetes is rising, but the role of gum disease in the origin of the disease is still unclear. According to Zuk, it’s critical to explore the impact of novel risk factors associated with disease risk.

The study, published in BMJ Open Diabetes Research and Care, uses National Health and Nutrition Examination Survey data on the U.S. population. Participants were over the age of 30, and health interviews and physical measurements were conducted in-home and at a mobile examination centre.

Vitamin D is predominantly produced in the skin from sun exposure or through the consumption of some foods. Gum disease is caused through an excess and persistence of gum inflammation that result from oral microbes. At its worst, poorly controlled diabetes worsens periodontal disease. Researchers have found that half of American adults have some form of gum disease and lack vitamin D sufficiency.

Zuk hopes that by better understanding exposures, targeted treatment can be an additional line of defense against diabetes. For example, by changing the vitamin D status from low to high among adults with periodontitis could affect glucose levels in people living with Type 2 diabetes.

“Because it’s the first study, we really need to look at these two exposures again in other studies and population. It might impact further diabetes research,” said Zuk, who was supervised by Laura Rosella, an associate professor at Dalla Lana.

More information: Aleksandra M Zuk et al. Joint effects of serum vitamin D insufficiency and periodontitis on insulin resistance, pre-diabetes, and type 2 diabetes: results from the National Health and Nutrition Examination Survey (NHANES) 2009–2010, BMJ Open Diabetes Research & Care (2018). DOI: 10.1136/bmjdrc-2018-000535

See also: https://medicalxpress.com/diabetes-news/ – Diabetes news
               https://medicalxpress.com/ – Medical and Health news

The University of Granada School of Dentistry reports that men with severe gum disease are more than twice as likely to suffer from erectile dysfunction, adjusting for biochemical markers and other comorbidities.

The researchers conducted a case-control study involving 80 male subjects with erectile dysfunction, based on the International Index of Erectile Function, and 78 controls. Each subject received a periodontal examination as well.

Also, the researchers gathered socioeconomic data and assessed each subject’s testosterone, lipid profile, C-reactive protein, and glycemic parameters. They then compared all variables between the groups and performed multivariate logistic regression analyses.

According to the researchers, 74% of the subjects with erectile dysfunction also presented chronic periodontitis, including higher numbers of sites with pocket probing depth between 4 and 6 mm and higher numbers of sites with clinical attachment loss of greater than 3 mm.

Triglycerides, C-reactive protein, and glycosylated hemoglobin were higher in these cases as well. The researchers concluded, then, that patients with chronic periodontitis were more likely to have erectile dysfunction independent of other confounders. Treating the periodontitis may result in improved erectile function, the researchers added.

“As startling as these findings may be, it may turn out to be a wakeup call for men to start paying attention to their oral health, particularly their gums,” said Dr. Nigel Carter, OBE, CEO of the Oral Health Foundation.

“In recent years, gum disease has been linked with conditions like diabetes, stroke, and heart disease, but an increased risk of coming up short in the bedroom may be the final straw for men who might have been reluctant to spend a little extra time looking after their gums,” Carter said.

The study, “Chronic Periodontitis Is Associated with Erectile Dysfunction. A Case-Control Study in European Population,” was published in the Journal of Clinical Periodontology.