Tag Archives: Oral

Impact of Abnormal Oral Microbiome on Obesity: Key Characteristics and Insights

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Bacteria in the oral cavity

Oral Bacteria (Blue) on Human Cheek Cells (Yellow) in Scanning Electron Micrograph

Steve Gschmeisner/Science Photo Library

Recent research has revealed that individuals with obesity exhibit unique oral microbiome characteristics. This finding could pave the way for early detection and prevention strategies for obesity.

The diverse community of microorganisms in our gut significantly impacts weight gain, being commonly linked to obesity and various metabolic conditions. Notably, up to 700 species of bacteria have been implicated in obesity and overall health.

“Given that the oral microbiome is the second largest microbial ecosystem in the human body, we aimed to investigate its association with systemic diseases,” says Ashish Jha, from New York University, Abu Dhabi.

Jha and his team analyzed saliva samples from 628 adults in the United Arab Emirates, 97 of whom were classified as obese. They compared these samples with a control group of 95 individuals of healthy weight, similar in age, gender, lifestyle, oral health, and tooth brushing habits.

The analysis showed that the oral microbiome of obese individuals has a higher abundance of inflammation-causing bacteria, such as Streptococcus parasanguinis and Actinobacterium oris. Additionally, Oribacterium sinus produces lactic acid, which is linked to poor metabolic health.

Jha and his colleagues identified 94 distinct differences in metabolic pathways between the two groups. Obese participants demonstrated enhanced mechanisms for carbohydrate metabolism and the breakdown of histidine, while their capability to produce B vitamins and heme—crucial for oxygen transport—was reduced.

Metabolites notably generated in obese individuals include lactate, histidine derivatives, choline, uridine, and uracil, which are associated with metabolic dysfunction indicators such as elevated triglycerides, liver enzymes, and blood glucose levels.

“When we analyze these findings collectively, a metabolic pattern surfaces. Our data indicates that the oral environment in obesity is characterized by low pH, high carbohydrate levels, and pro-inflammatory conditions,” notes Lindsey Edwards from King’s College London. “This study offers compelling evidence that the oral microbiome may reflect and contribute to the metabolic changes associated with obesity.”

Currently, these findings suggest a correlation rather than causation. “While some associations are surprising, we cannot determine cause and effect as of now, which remains our next focus,” Jha states.

To explore whether the oral microbiome contributes to obesity or is modified by it, Jha and his team plan further experiments analyzing both saliva and gut microbiomes to investigate potential microbial and metabolic transfers.

Professor Jha believes this is plausible, as the mouth’s extensive blood vessel network facilitates nutrient absorption and taste sensing, potentially allowing metabolites direct access to the bloodstream, influencing other bodily systems.

Establishing a causal connection will also necessitate randomized controlled trials and detailed metabolic pathway analyses, according to Edwards.

As dietary patterns evolve, specific food components may become more readily metabolized by certain bacteria, leading to increased microbial activity that can influence cravings and potentially lead to obesity, Jha explains. For instance, uridine has been shown to promote higher calorie intake.

If oral bacteria are demonstrated to influence obesity, Edwards suggests it could lead to innovative interventions, such as introducing beneficial oral microbes through gels, using prebiotics to foster specific bacterial growth, or employing targeted antimicrobials. “Behavioral strategies, like reducing sugar intake, can also significantly contribute to obesity prevention,” she adds.

Even if the oral microbiome acts as a consequence rather than a cause of obesity, its assessment can still provide valuable insights. Saliva tests can easily detect distinct microbial changes, which Jha believes could be useful for early obesity detection and prevention strategies.

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Source: www.newscientist.com

Significant Shifts in Oral Microbiome During Pregnancy Could Contribute to Tooth Loss

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Maintaining good oral hygiene may be especially important during pregnancy

Chondros Eva Catalin/Getty Images

A popular saying suggests that “if you give birth to a child, your teeth will fall out.” While pregnancy is known to elevate the risk of dental issues, the underlying reasons remain somewhat unclear. Recent studies indicate that the oral microbiome alters during pregnancy, becoming less diverse and potentially more susceptible to inflammation.

Hormonal changes during pregnancy are often cited as the main culprits for the increased risk of conditions like periodontal disease and tooth decay. Moreover, there’s a widespread belief that the fetus extracts calcium from the mother’s teeth, a notion that lacks scientific backing.

Disruption of the oral microbiome, which comprises over 700 bacterial species, can lead to dental issues regardless of pregnancy status. However, Yoram Luzon and his team from Bar-Ilan University in Israel aimed to explore whether this typically stable ecosystem shifts during pregnancy. They collected saliva samples from 346 Israeli women across all three trimesters: 11-14 weeks, 24-28 weeks, and 32-38 weeks.

Their investigation revealed a decrease in species diversity in saliva samples starting from the transition between the first and second trimesters, continuing to decline throughout the pregnancy. A notable characteristic was the reduction in the number of species, with Akkermansia muciniphila, often hailed as a beneficial bacterium, declining alongside an increase in pro-inflammatory bacteria like Gammaproteobacteria and Synergystobacteria.

“While the oral microbiome is generally stable, we have noted a gradual decrease in its diversity over the years,” Louzoun observes. “Pregnancy accelerates this slow evolution, allowing changes that typically take years to manifest in just nine months.”

Despite being relatively minor overall, numerous factors may contribute to these changes. “Pregnancy involves a multitude of hormonal shifts and inflammation, leading to alterations in your microbiome,” explains Lindsay Edwards from King’s College London. “Dietary changes are frequent during pregnancy, and various factors such as nausea, medication cessation, and altered eating habits all play a role.”

The participants filled out questionnaires regarding their diets and health, allowing the researchers to identify similar yet distinct effects among different women. This included those who followed a gluten-free diet, took antibiotics, experienced stress, or were current or former smokers. “Many women quit smoking during pregnancy, but their prior smoking habits can impact their microbiome,” notes Dr. Luzon, emphasizing the potential long-term effects.

A parallel study found similar changes in the oral microbiomes of 154 pregnant women in Russia during their second and third trimesters.

Although pregnancy heightens the risk of dental complications, particularly in the early stages, Luzon does not definitively link oral microbiome changes to these issues. “We can’t conclude whether these microbiome alterations are beneficial or detrimental, but they are undoubtedly changing rapidly,” he states.

Conversely, Edwards suggests that shifts in microbial composition might be a contributing factor, highlighting that saliva tends to become more acidic during pregnancy, altering the types of bacteria present.

Valentina Biagioli and her colleagues from the University of Genoa in Italy assert that changes in the oral microbiome may correlate with variations in systemic hormone levels, as both systems potentially influence each other. “There exists a plausible biological link connecting the observed microbiome changes to prevalent dental issues during pregnancy, such as tooth loss,” she comments.

Disruption in the oral microbiome has been noted to relate to pregnancy complications. Consequently, establishing what constitutes an optimal microbiome during pregnancy could serve as a benchmark for monitoring pregnancy progression. “Once we establish the baseline oral microbiome of pregnancy, deviations can be detected,” Louzoun states.

Moreover, ongoing research aims to elucidate this microbiome’s role in the immune system, affecting both the health of the pregnant woman and her unborn child. “The microbiome is instrumental in shaping the immune system, fostering a reciprocal relationship,” Edwards explains.

In light of this, enhancing our understanding of how to sustain a healthy oral microbiome (e.g., via good dental hygiene and a balanced, nutritious diet) could yield significant benefits. “Microbiome changes may influence the inflammatory state of expectant parents and better prepare the child’s immune system, potentially affecting long-term health, allergies, infection susceptibility, and chronic inflammatory conditions,” cautions Edwards.

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Source: www.newscientist.com

Richard III’s Oral Microbiome Indicates Severe Periodontal Disease

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Richard III’s skull

Carl Vivian/University of Leicester

The oral microbiome extracted from King Richard III, derived from analysis of his dental plaque, indicates he may have suffered from a condition that could lead to jaw deterioration.

In 2012, the skeletal remains of Richard III were found beneath a parking lot at the former Greyfriars Church in Leicester, England. Initially thought to be Richard III—who was killed in the Battle of Bosworth Field in 1485 and interred in Leicester—dental and skeletal evidence, including a head wound and spinal curvature, correlated with descriptions from his death. Subsequent genetic tests confirmed the identity of the remains.

Although Richard’s reign only lasted two years amid the Wars of the Roses, he significantly impacted English history, with allegations of plotting against his nephews while they were imprisoned in the Tower of London, alongside William Shakespeare’s portrayal of him as a malevolent figure in his famous play.

Nevertheless, details of Richard’s daily existence are scarce. To uncover more, Turi King and fellow researchers at the University of Bath, UK, collected samples of tartar—hardened dental plaque—from three of his well-preserved teeth.

Dental plaque is effectively a time capsule, retaining DNA from microorganisms and remnants of food. “The quantity of DNA obtained from Richard III’s tartar is among the highest recorded in archaeological contexts,” the researchers stated, noting the detection of over 400 million DNA sequences.

“No one has previously sequenced 400 million ancient DNA fragments; it’s an astonishing figure,” remarks Laura Weyrich from Pennsylvania State University. “This indicates that our capabilities with ancient DNA are likely more extensive than previously thought.”

Dr. King and his team identified almost 400 microbial species from the DNA, comparable in variety to samples from well-preserved dental tartar across Britain, Ireland, Germany, and the Netherlands over the last 7,000 years, spanning from the Neolithic to modern times. “It suggests that elite populations shared microbial strains akin to those of the broader populace, despite their affluent lifestyles and experiences,” Weyrich notes.

However, the research team could not collect adequate plant or animal DNA to determine Richard’s dietary habits. Nevertheless, previous studies on his bones from his last two years indicated he drank non-local wine and consumed large quantities of game, fish, and birds, including swans and herons.

Professor Weyrich indicated that results regarding the microbiome could vary if the team obtained samples from more than one tooth and compared them to similar teeth from groups in Germany or the Netherlands. She also mentioned that their limited sampling does not provide a comprehensive view of Richard’s oral microbiome, as distinct bacteria inhabit different areas of the mouth and different surfaces of the teeth.

The king’s well-preserved teeth may provide insights into his oral microbiome.

Carl Vivian/University of Leicester

One particularly prevalent bacterium identified is Tannerella forsythia, which is linked to periodontal disease, a serious gum infection that can lead to bone loss around the teeth. Given the poor oral hygiene of the 15th century, Richard had a cavity when he died at age 32, though this does not automatically indicate he had periodontal disease.

“Many individuals may harbor potentially harmful bacteria without becoming ill, while others could become infected,” explains Pierre Stollforth from the Leibniz Institute for Natural Products Research and Infection Biology in Germany. Weyrich adds that examining bone loss in the jaw could reveal if Richard suffered from periodontal disease.

“I’m particularly passionate about bridging social science, history, and genetics,” Stallforth states. “Having access to the dental tartar of historical figures is extraordinary as it enables us to gain deeper insights into their lives.”

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Source: www.newscientist.com

The Timing of Your Oral Exam Can Influence Your Success or Failure

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Certain university courses, such as language, have oral assessments

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A study involving more than 100,000 ratings shows that university students tend to have a higher success rate in oral exams when tested around noon.

Carmelo Vicario from the University of Messina in Italy began investigating this trend after noting similar findings in a prior research study on how jury decisions can be affected by meal times. “We aimed to explore if this phenomenon also extends to educational settings,” Vicario stated.

Along with his team, Vicario examined data from a public database, analyzing the results and timings of over 104,500 oral assessments from approximately 19,000 university students in Italy. These assessments took place from October 2018 to February 2020, starting with the 1243 course.

The researchers discovered an average pass rate of 54% at 8 AM, which increased to 72% by noon, before dropping to 51% by 4 PM. “We observed a remarkable bell-shaped distribution in our findings,” Vicario noted.

This trend was consistent across various types of oral assessments, including language examinations and research presentations. However, it’s uncertain whether this trend is applicable to written tests.

“Numerous external factors influence student performance,” according to Thomas Lancaster from Imperial College London. “Scheduling can make a difference—be it the time of day or even the intervals between exams.”

The reasons behind these variations are complex and often difficult to untangle. They could relate to natural patterns of sleep among students.

Research indicates that younger individuals often lean toward being night owls, which can misalign with the chronotypes of older examiners. The closest alignment tends to occur around noon.

During this time, there may be a balance between students who perform optimally and those who are more lenient with their grading. “As always, the best outcomes tend to find a middle ground,” Vicario shared, expressing hope that this research will inform universities in scheduling oral exams.

“Personally, I believe we should utilize this data to advocate that students avoid scheduling Vivas (oral defenses of their theses) or presentations before 10 AM,” Lancaster recommended.

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Source: www.newscientist.com

A New Perspective on Oral Healing: Paving the Way to a “Woundless World”

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Fibroblast cells that play a role in forming connective tissue and are also involved in scarring

Dr. Torsten Wittmann/Science Photography Library

Recent discoveries about how mouth injuries heal without bruising could lead to treatment methods that prevent permanent scars and improve skin appearance.

“Millions of individuals experience injuries, surgeries, burns, and various other traumas,” states Ophir Klein from Cedars-Sinai Medical Center in Los Angeles, California. “This represents a significant issue not only in cosmetic terms but also functional terms,” he adds. For instance, he mentions that a major wound can restrict leg movement due to skin tightening.

To explore this, Klein and his team took advantage of the fact that mouth wounds heal without scarring. “Injuries inside the mouth heal more quickly and with fewer scars compared to skin injuries,” he explains.

Upon investigation, the researchers created 2.5mm wide wounds both in the mouth and on the face of mice. They collected tissue samples as these wounds healed over the course of a week.

The team analyzed cells known as fibroblasts that are associated with scarring and discovered that fibroblasts in the mouth exhibited higher activity levels for genes encoding proteins such as Gas6 and Axl than those in the skin. These proteins are known to promote cell growth, migration, and survival.

The Gas6-Axl pathway seemed to inhibit the levels of a protein called FAK, which is involved in depositing proteins on wounds, leading to scar formation. “We were aware of this pathway’s existence, but its role in non-scarring wound healing was unknown,” Klein notes.

The next step for the researchers was to assess whether enhancing the Gas6-Axl pathway could minimize skin scarring. They administered a solution containing Gas6 to freshly created facial scars on mice. After two weeks, these treated wounds exhibited reduced FAK levels and fewer scars compared to those in untreated mice. “They have successfully shown that stimulating this pathway can diminish scarring,” says Jason Wong at the University of Manchester, UK.

“This is certainly a significant step towards what could be a scar-free future,” states Ines Sequeira from Queen Mary University in London. However, he cautions that further research is needed with larger animals like pigs, which have skin more similar to humans, before moving towards human trials.

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Source: www.newscientist.com

The use of oral contraceptives correlates with decreased rates of depression

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One study found that women who currently use oral contraceptives have lower rates of depression than women who previously used them. The study, which included 6,239 American women, suggests that reduced pregnancy concerns and potential “survivor bias” may explain this difference.

Researchers analyzed data from 6,239 women in the United States in the new study.

A recent study revealed that women who use oral contraceptive pills (OCP) are less likely to experience depression.

The study analyzed data from 6,239 U.S. women between the ages of 18 and 55. They found that current OCP users had a significantly lower rate of major depression at 4.6%, compared to 11.4% for women who had previously used OCPs.

The study was led by researchers at Anglia Ruskin University (ARU), along with experts from the Dana-Farber Cancer Institute in Boston and the University of California, Davis.

Possible explanations and observations

The researchers suggest two possible explanations for the study results that run counter to the commonly held belief that OCPs can cause depression.

One is that taking the pill relieves anxiety about unwanted pregnancies and helps OCP users improve their mental health. The results may also have been influenced by “survivor bias,” where women who experienced signs of depression while using OCPs stopped taking them and were placed in the category of former users.

This cross-sectional study used data collected by the Centers for Disease Control and Prevention and controlled for demographic characteristics, chronic conditions, and antidepressant use.

Among both users and former users, women who were widowed, divorced or separated, obese, or had a history of cancer were more likely to report depression. Additionally, among former users, depression was more commonly reported among women who were black or Hispanic, smoked, had lower education, or experienced poverty.

Meaning and comments

Dr Julia Gawronska, lead author and postdoctoral researcher at Anglia Ruskin University (ARU), said: “Contraception is an important component of preventive health care. Most women tolerate oral contraceptives without experiencing symptoms of depression, but some women experience unpleasant side effects and even depression. It is possible to develop a disease, and the reasons for this are not entirely clear.

“Unlike some previous studies, we found that women currently taking oral contraceptives reported more clinically relevant depression than women who previously took oral contraceptives. Turns out it’s much less likely.

“Taking the pill may have positive mental health effects for some women simply by relieving them of anxiety about pregnancy. A ‘survivor effect’ may also be at play. Women who experience symptoms of depression are more likely to stop taking the drug, placing them in a group of former users.

“However, stopping the pill without a suitable alternative increases the risk of unplanned pregnancy. Make sure women are well supported, well informed and provided with alternative contraceptive methods if necessary.” It is important that it be done.”

References: “The Association between Oral Contraceptive Use and Depression in U.S. Women” by Julia Gawronska, Katherine Meese, Lee Smith, Chao Cao, Nan Wang, and Susan Walker, October 11, 2023. Affective Disorders Journal.
DOI: 10.1016/j.jad.2023.10.041

Source: scitechdaily.com